Key: 3 Medline: Authors: Abdulkader N;Brun JL Title: Induction, detection and isolation of temperature-sensitive lethal and/or sterile mutants in nematodes. I. The free-living nematode C. elegans. Citation: Revue de Nematologie 1: 27-37 1978 Type: ARTICLE Genes: Abstract: Applying a series of techniques intended to induce, detect and isolate lethal and/or sterile temperature-sensitive mutants, specific to the self-fertilizing hermaphrodite nematode Caenorhabditis elegans, Bergerac strain, 25 such mutants have been found. Optimal conditions for the application of mutagenic treatment and the detection of such mutations are discussed. ------------------- Key: 5 Medline: Authors: Abi-Rached M;Brun JL Title: Etude ultrastructurale des relations entre ovocytes et rachis au cours de l'ovogenese du nematode C. elegans. Citation: Nematologica 21: 151-162 1975 Type: ARTICLE Genes: Abstract: Before diakinesis, the development of the oocytes of C. elegans takes place in the presence of a specific anatomical structure: the rachis. This is an undivided, anucleated cytoplasmic mass placed in the central part of the ovary. Electron microscopy shows that, at first, in the gonial region, it is made of two branches which infiltrate themselves between the oogonia and then converge in a single axial column. Afterwards, this column will be pushed to the outside of the gonad and will disappear when the great oocyte increase takes place. Until then, the rachis is limited by its own envelope and connects each germinal cell through a pore present in the double layered membrane. The cytoplasmic bridge established between the oogonia and the rachis, the presence of a typical Golgi apparatus and of numerous mitochondria in the rachis strongly suggest that the rachis plays a role in the oocyte ------------------- Key: 6 Medline: Authors: Abi-Rached M;Brun JL Title: Ultrastructural changes in the nuclear and perinuclear regions of the oogonia and primary oocytes of C. elegans, Bergerac strain. Citation: Revue de Nematologie 1: 63-72 1978 Type: ARTICLE Genes: Abstract: Electron microscope studies in and around the nucleus of C. elegans oogonia and primary oocytes showed fibrogranular formations whose presence is not always constant. The nucleolus, very large in the first oogenetic stages, disappeared during early diakinesis. In pachytene and diplotene, it underwent a vacuolization phase in its central part. Perinuclear corpuscules and groups of granules were limited to the vitellogenetic phase of meiotic I prophase: they were localized in the vicinity of the nuclear membrane and nucleolus. The perinuclear formations, detectable as early as germigene, remained until full ooplasmic growth. Their localization at the limit of the nucleus led to their involvement in the exchange processes which took place between the nucleolus and the cytoplasm, by way of the perinucleolar granules and ------------------- Key: 7 Medline: Authors: Abi-Rached M;Brun JL Title: Changes in the synaptonemal complex in the oocyte nucleus in meiotic prophase of C. elegans. Citation: C.R. des Seances de l'Academie des Sciences Serie D 288: 425-428 1979 Type: ARTICLE Genes: Abstract: During oogenesis in the hermaphroditic nematode C. elegans, the synaptonemal complex is not detectable until the homologous chromosomes are at least partly paired (that is until meiotic prophase synapsis). In the pachytene stage, the complex has a typically classic organization. At the separation phase, the complex persists in certain places, in the diplotene stage and even in early diakinesis. These zones which persist during separation of the homologous chromosomes are believed to correspond to chiasma. This interpretation therefore implicates the complex in the recombination mechanism. ------------------- Key: 8 Medline: 78127686 Authors: Albertson DG;Sulston JE;White JG Title: Cell cycling and DNA replication in a mutant blocked in cell division in the nematode C. elegans. Citation: Developmental Biology 63: 165-178 1978 Type: ARTICLE Genes: lin-5 nuc-1 Abstract: The postembryonic development of the nematode Caenorhabditis elegans has been described at the level of individual cell lineages. A mutant of postembryonic development, lin-5 II, causes a failure of postembryonic nuclear and cell divisions. Mitosis in living animals is seen by light microscopy to proceed through prophase and nuclear envelope breakdown, but an abnormal-looking metaphase plate forms in the mutant, after which the interphase nuclear morphology reappears until the next attempted round of division. The precursor cells which give rise to the ventral nerve cord have been studied in lin-5. In the wild type these cells divide asymmetrically to give six descendants (one hypodermal cell and five neurons). In the mutant these precursors accumulate approximately six times the diploid quantity of DNA within a single nucleus, while attempting mitosis up to three times. These polyploid cells display characteristics of cells they would have produced ordinarily. ------------------- Key: 9 Medline: 76269913 Authors: Albertson DG;Thomson JN Title: The pharynx of C. elegans. Citation: Philosophical Transactions of the Royal Society of London 275B: 299-325 1976 Type: ARTICLE Genes: Abstract: The anatomy of the pharynx of Caenorhabditis elegans has been reconstructed from electron micrographs of serial sections. The pharynx is used for pumping food into the gut, and is composed of 34 muscle cells, 9 marginal cells, 9 epithelial cells, 5 gland cells and 20 neurones. Three regions of specialization in the cuticle lining of the pharyngeal lumen may aid in the accumulation of food particles. A basement membrane isolates the pharynx from the rest of the animal, making the pharyngeal nervous system a nearly self-contained unit which is composed primarily of five classes of motor neurones and six classes of interneurones. Three other classes have also been described, which by their morphology appear to be neurosecretory and motor, motor and interneuronal, and lastly one pair that only innervates three of the marginal cells. Some classes of neurone have free endings just under the cuticle lining the lumen of the pharynx, suggesting that these are mechano- or proprio-receptive endings. The connectivity of these neurones has been described at the level of individual synaptic regions, and after combining this information with video taped observations of the pharynx pumping, some interpretations of how these neurones function have been offered. ------------------- Key: 10 Medline: Authors: Ali M;Wahab A;El-Kifel AH Title: Nematodes associated with Coleoptera species in Egypt Part 2. Citation: Parasitologia Hungarica 6: 169-188 1973 Type: ARTICLE Genes: Abstract: ------------------- Key: 11 Medline: Authors: Anderson GL Title: Responses of dauerlarvae of C. elegans (Nematoda: Rhabditidae) to thermal stress and oxygen deprivation. Citation: Canadian Journal of Zoology 56: 1786-1791 1978 Type: ARTICLE Genes: Abstract: Larval forms of the free-living nematode Caenorhabditis elegans possess the ability to enter a developmental stage which is thought to be specialized for survival in harsh environmental conditions, i.e. the dauerlarval stage. In this study the responses of dauerlarvae to thermal stress and oxygen deprivation are investigated. Oxygen consumption of dauerlarvae is less sensitive to temperature change than that of adults, with Q10 values of 1.7 and 2.6 respectively. The upper thermal tolerance limit of dauerlarvae is also different from that of adults; dauerlarvae survive approximately three times longer than adults when exposed to 37C. In addition to differences in thermal tolerance, dauerlarvae surrvive longer under anaerobic conditions than adults, 7 days and 2 days respectively. On recovery from anaerobic stress dauerlarvae exhibit behavior changes which are suggestive of emergence from the dauerlarval stage. The responses of dauerlarvae to thermal stress and oxygen deprivation appear to be important aspects of the specialization for survival ------------------- Key: 12 Medline: Authors: Anderson GL;Dusenbery DB Title: Critical oxygen tension of C. elegans. Citation: Journal of Nematology 9: 253-254 1977 Type: ARTICLE Genes: Abstract: Regulators are able to maintain a stable oxygen consumption, despite variations in ambient tension, down to a characteristically low "critical" oxygen tension. Below this tension, oxygen consumption is a function of ambient oxygen tension. Free-living nematodes are generally reported to have low critical oxygen tensions; i.e., they generally behave as regulators with respect to oxygen consumption. Caenorhabditis briggsae, a commonly studied free-living nematode, behaves as a regulator with a reported critical oxygen tension of 38 mm Hg. A closely related species, Caenorhabditis elegans, is reported to have a much higher critical oxygen tension, approximately 122 mm Hg. Caenorhabditis elegans would, therefore, be an exception to the generalization that free-living nematodes are regulators. The current study was undertaken to re-evaluate the influence of oxygen tension upon oxygen consumption in this species. A more accurate estimate of its critical oxygen tension may be useful in view of the increasing use of the species as an experimental model. ------------------- Key: 14 Medline: Authors: Andrew PA;Nicholas WL Title: Effect of bacteria on dispersal of C. elegans Citation: Nematologica 22: 451-461 1976 Type: ARTICLE Genes: Abstract: The dispersal and behavior of Caenorhabditis elegans in the presence of various species of bacteria were studied on agar plates. Several species proved attractive to the nematode, the proximity of colonies of living bacteria increasing the rate of dispersal of the nematodes, which on contact tended to remain within the colonies feeding on the bacteria. Other species showed little attraction, or proved repellent. Escherichia coli, Pseudomonas fluorescens and P. aeruginosa were attractive as well as supporting growth and reproduction of the nematode. Dead bacteria were unattractive. Bacillus megatherium repelled ------------------- Key: 15 Medline: Authors: Ward S Title: Genetic studies of chemotaxis mutants in nematodes. Citation: Experimental Neurology 48: 58-59 1975 Type: NEWS Genes: Abstract: The precision of neuronal development is programmed genetically. The genes involved must be expressed in an orderly sequence so that their products appear in the right cell at the right time. By studying mutants in which this sequence is altered, it should be possible to dissect the development and recognize the steps controlled by individual genes.... ------------------- Key: 16 Medline: Authors: Babu P Title: Biochemical genetics of C. elegans. Citation: Molecular & General Genetics 135: 39-44 1974 Type: ARTICLE Genes: flu-1 flu-2 flu-3 flu-4 Abstract: A new method of isolating mutants of the free-living nematode Caenorhabditis elegans is described. This method utilizes the fluorescence of the nematode as the phenotype. 15 mutants belonging to four genes obtained using this technique have been characterised. Mutants in two of these genes are shown to have blocks in tryptophan catabolism. It is suggested that this method could be used to obtain mutants corresponding to blocks in other metabolic pathways with fluorescent end products. ------------------- Key: 21 Medline: 72243209 Authors: Beguet B Title: The persistence of processes regulating the level of reproduction in the herm nematode C. elegans, despite parental aging/ Citation: Experimental Gerontology 7: 207-218 1972 Type: ARTICLE Genes: Abstract: Starting with a laboratory strain of C. elegans, a self-fertilizing hermaphrodite nematode, 2 experimental series (Y from young parents and O from old parents) were selectively maintained over 9 consecutive generations. Each series was characterized by the age of the parents from which each generation was derived (5 and 8 days respectively). The differential behaviour of the average fecundity in these two series was studied systematically in each generation. First of all it could be shown that fecundity was significantly reduced in the first 4 generations of the O series. Then, in the 5th generation, the fecundity of the O series returned to a level similar to that of the Y series. The regulation thus demonstrated in C. elegans contrasts with the results obtained in most work on aging, from which it would appear rather to be linked to a disorganization of the homeostatic processes. The regulatory processes noted were identified by means of the comparative analysis of the various lines maintained in individual cultures. Two explanatory hypotheses are put forward to try to link the regulation seen with the selection obtained. ------------------- Key: 22 Medline: Authors: Beguet B Title: Un exemple de derive meiotique chez un nematode libre autofecond C. elegans. Citation: C.R. des Seances de l'Academie des Sciences Serie D 279: 2115-2118 1974 Type: ARTICLE Genes: Abstract: In French. ------------------- Key: 23 Medline: Authors: Beguet B Title: Cryoconservation de mutants "femelle-steriles" d'un nematode libre hermaphrodite C. elegans a la temperature de l'azote liquide. Citation: Bulletin de la Societe Zoologique de France 101: 137-137 1976 Type: ARTICLE Genes: Abstract: In French. ------------------- Key: 24 Medline: Authors: Beguet B Title: Genetique de la physiologie ovocytaire chez un nematode libre autofecond C. elegans. I. Influence du genotype et selection/ Citation: Genetica 45: 405-424 1975 Type: ARTICLE Genes: Abstract: In the free-living hermaproditic autogamous nematode C. elegans, a strain heterozygous at one locus, which controls size but also has a pleiotropic effect on fecundity, was created artificially. We have studied the inbreeding effects on fecundity and viability for the three genotypes obtained by self-fertilization with controlled cultures submitted to intensive inbreeding. An effect which produced a 10% significant reduction in homozygote wild type fecundity was found. After four generations, the fecundity of homozygous wild type returned to the heterozygous level. The initial reduction in fecundity is caused by the low viability of the homozygous eggs. This is an expression of the genetic load. A hypothesis is suggested concerning the next homozygous generations: the regulatory processes specific to inbreeding would contribute to maintaining the best genetic state. ------------------- Key: 25 Medline: Authors: Beguet B Title: Etude genetique d'un mutant meiotique dominant chez C. elegans, souche Bergerac. Citation: Revue de Nematologie 1: 39-45 1978 Type: ARTICLE Genes: Abstract: In Caenorhabditis elegans, wild-type hermaphrodites produce by self-fertilization hermaphrodites mainly with only a low frequency of males (10*-3). This XO male progeny is produced by nullo-X gametes. A mutant with increased frequency of males was found during a search for ethane-methane-sulfonate induced mutants. This mutation f69 dm is dominant and is located in an autosomal linkage group. Homozygous him/him or heterozygous him/+ hermaphrodite for this mutation gave rise to approximatively 20% males. They also produced 17% sterile hermaphrodites. Such mutants might allow analysis of meiosis in this organism because it reflects some kind of chromosomal abnormality. Probably, X loss occurs by a meiotic nondisjunction mechanism in both gametic lines. ------------------- Key: 26 Medline: 72243208 Authors: Beguet B;Brun JL Title: Influence of parental aging on the reproduction of the F1 generation in a hermaphrodite nematode C. elegans. Citation: Experimental Gerontology 7: 195-206 1972 Type: ARTICLE Genes: Abstract: In the free-living hermaphrodite autogamous nematode C. elegans, parental senescence generally leads to a significant reduction in the number of F2 adults derived from F1 parents. Indeed, this reduction is seen in 70 per cent of lines. It is related to changes in the reproductive mechanisms of the F1 generation, affecting both the physiology of the gonad and the products of the ovotestis: Earlier sexual maturation of the F1 O hermphrodite derived from elderly parents (4 1/4 days instead of 4 1/2 days); A 15 per cent reduction in the number of spermatozoa produced by the F1 O; An increase in the mortality of F2 O eggs, rising to 50 per cent in eggs laid on the last day. These findings suggest that the causes of the reduction of fecundity arise during oogenesis in the F1 O subjects. It is principally the cytoplasm of the ooctye that appears to be affected. Various hypotheses are put forward concerning the way in which this prolonged ------------------- Key: 27 Medline: Authors: Beguet B;Gibert M-A Title: Obtaining a self-fertilizing hermaphrodite mutant with a male copulatory bursa in the free-living nematode C. elegans var. Bergerac. Citation: C.R. des Seances de l'Academie des Sciences Serie D 286: 989-992 1978 Type: ARTICLE Genes: tra-2 Abstract: The ethylmethanesulfonate, acting on larva of the wild type strain of Caenorhabditis elegans, allowed us to isolate a recessive mutant, f70, with an abnormal sexual differentiation. Both the gonad and genital tractus which are phenotypically hermaphrodite and functional and the copulatory bursa which is typical of the rare males (1/1000) usually observed in such a population are found on this self-fertilizing mutant. The mutation threw off the repression of the mitotic division mechanisms in some postembryonic cellular lineages normally blocked in the hermaphrodite wild type. ------------------- Key: 28 Medline: 70112698 Authors: Behme R;Pasternak J Title: DNA base composition of some free living nematode species. Citation: Canadian Journal of Genetics & Cytology 11: 993-1000 1969 Type: ARTICLE Genes: Abstract: The mean base compositions (% GC) of DNA samples from five free-living nematodes were determined by CsCl equilibrium buoyant-density centrifugation and thermal denaturation studies. Both methods gave similar results indicating that there is no extensive replacement of the usual bases in nematode DNA. From the ultracentrifugation studies the % GC content of the DNA of Caenorhabditis briggsae, Turbatrix aceti, Rhabditis (Rhabditis) anomala, Panagrellus redivivus, and Panagrellus silusiae was 36, 40, 42, 44 and 44, respectively. The sample of DNA from T. aceti showed two distinct ultraviolet absorbing bands in a CsCl gradient. The band at 1,688 g/cm3 proved to be a polysaccharide. It gave a distinctive refractive index pattern when viewed with the schlieren optical system, was insensitive to DNase treatment and was removed by a-amylase treatment. On the other hand, the material banding at 1,699 g/cm3 was shown to be DNA. This band produced no disturbance in the refractive index gradient. It was not altered by a-amylase treatment, but it was DNase sensitive. Since P. redivivus and P. silusiae were found to have the same DNA base composition their ability to interbreed was examined. These two forms were cross-fertile and the ------------------- Key: 29 Medline: Authors: Bird AF Title: A method of distinguishing between living and dead nematodes by enzymatically induced fluorescence. Citation: Journal of Nematology 11: 103-105 1979 Type: ARTICLE Genes: Abstract: Since it is sometimes difficult to distinguish between living and dead nematodes, dyes are used, such as New Blue R, Chrysoidin, Eosin-Y, and several fluorochromes, with varied success. A method is described here that is rapid (results in 15 min) and has a mechanism of staining that is understood. The technique was described first by Rotman and Papermaster, working with living mammalian cells, and later by Heslop-Harrison and Heslop-Harrison, working with plant material. It takes advantage of the presence of esterases which hydrolyse nonfluorescent fatty acid esters of fluorescein to yield fluorescein, which accumulates and is detectable by its fluorescence. Since esterases are known to be present in quantity in nematodes, concentrated principally in the nervous system, male spicules, and gut, this technique seemed worth testing as a rapid means of distinguishing between living and dead nematodes. ------------------- Key: 30 Medline: 76207304 Authors: Brenner S Title: The genetics of behaviour. Citation: British Medical Bulletin 29: 269-271 1973 Type: REVIEW Genes: unc-5 unc-30 Abstract: There is growing interest in the study of the genetics of behaviour. No one can doubt that the behaviour patterns of higher organisms are central for their existence and survival and that changes in these patterns have accompanied evolutionary diversification. Micro-organisms pursue a mode of existence close to the molecular level and very little is interposed between the environment and the biochemical machinery of uptake, biosynthesis and replication. The opposite is true of higher organisms, where we find an elaborate apparatus that is responsible for the generation and control of movement, for the detection of food and for mating. Much of this is genetically determined and, particularly in invertebrates, there are complex sequences of behaviour which are not learnt but are programmed by the genes. ------------------- Key: 31 Medline: 74271161 Authors: Brenner S Title: The genetics of Caenorhabditis elegans. Citation: Genetics 77: 71-94 1974 Type: ARTICLE Genes: bli-1 bli-2 bli-3 bli-4 bli-5 dpy-1 dpy-2 dpy-3 dpy-5 dpy-6 dpy-7 dpy-8 dpy-9 dpy-10 dpy-11 dpy-13 dpy-14 dpy-17 dpy-18 lev-1 lon-1 lon-2 rol-1 rol-3 sma-1 sma-2 sma-3 sma-4 sqt-3 unc-1 unc-2 unc-3 unc-4 unc-5 unc-6 unc-7 unc-8 unc-9 unc-10 unc-11 unc-13 unc-14 unc-15 unc-16 unc-17 unc-18 unc-20 unc-23 unc-24 unc-25 unc-26 unc-27 unc-29 unc-30 unc-31 unc-32 unc-33 unc-34 unc-35 unc-36 unc-37 unc-38 unc-39 unc-40 unc-41 unc-42 unc-43 unc-44 unc-45 unc-46 unc-47 unc-49 unc-50 unc-51 unc-53 unc-55 unc-57 unc-58 unc-59 unc-60 unc-61 unc-62 unc-63 unc-64 unc-65 unc-67 unc-68 unc-69 unc-70 unc-71 unc-73 unc-74 unc-75 unc-76 unc-77 vab-1 vab-2 vab-5 Abstract: Methods are described for the isolation, complementation and mapping of mutants of Caenorhabditis elegans, a small free-living nematode worm. About 300 EMS-induced mutants affecting behavior and morphology have been characterized and about one hundred genes have been defined. Mutations in 77 of these alter movement of the animal. Estimates of the induced mutation frequency of both the visible mutants and X chromosome lethals suggest that, just as in Drosophila, the genetic units in C. elegans are large. ------------------- Key: 33 Medline: Authors: Brun J Title: Evolution de la prophase meiotique chez C. elegans Maupas 1900, sous l'influence de temperature elevees. Citation: Bulletin Biologique de la France et de la Belgique 89: 326-346 1955 Type: ARTICLE Genes: Abstract: In French. ------------------- Key: 34 Medline: Authors: Brun J Title: Genetic adaptation of C. elegans (Nematoda) to high temperatures. Citation: Science 150: 1467- 1965 Type: ARTICLE Genes: Abstract: When taken directly from a strain kept for several years at 18C in the laboratory, Caenorhabditis elegans cannot reproduce indefinetely at temperatures higher than 22C. By progressive and very slow increments of the breeding temperature, a strain fecund at 24.5C was obtained. ------------------- Key: 36 Medline: Authors: Brun JL Title: L'adaptation aux temperatures elevees chez un nematode C. elegans Maupas 1900. I. L'adaptation et son evolution. Citation: Annales de Biologie Animale, Biochimie, Biophysique 6: 127-158 1966 Type: ARTICLE Genes: Abstract: Caenorhabditis elegans is a Nematode strain of almost exclusively hermaphroditic self-fertilizing animals. Since they are kept individually on an agar medium, it is easy to determine their fertilities. The Bergerac strain experimented upon had been kept for 700 generations at 18C when this investigation was started. Average fertility was 141 progeny per hermaphrodite. Under our experimental conditions, the animals could never be kept on after the 1st generation if they were raised from 18 to 24.5C straight off. But, they could lastingly withstand this temperature if a certain number of generations were previously kept at intervening temperatures, viz. 22, 23, 23.5 and 24. Shortly after the transfers to any one of these intermediate temperatures - or to 24.5C as well - , we noticed a gradual slowing down of fertility; a minimum was reached at the 5th or 6th generation. After this initial stage of sensitiveness, fertility was gradually increased in relation with the duration of breeding. The adaptive modification is very slow. At 23.5C for instance, it is after 100 generations only that a fertility four times greater than that of the first generation transferred is reached. It is only after 1000 generations that the Nematodes can withstand exposure to 24.5C. When a strain has become acclimatized to a higher temperature, it shows an intrinsic fertility greater than that of a strain acclimatized to a lower temperature. This can be observed when 23.5C adapted animals are taken down to 18C: their average fertility (=230) can then be compared with that of the animals kept at 18C throughout (=140). So, both the possible acclimatization to a higher temperature and the fertility at normal or lower temperatures are conditionned by the duration of breeding at a high temperature. Therefore, it appears that acclimatization results from a cumulative effect in the action of temperature. In the second part of this report, we shall see that these conclusions are enforced by the results of our investigations upon the durability of the acclimatization. ------------------- Key: 37 Medline: Authors: Brun JL Title: L'adptation aux temperatures elevees chez un nematode C. elegans Maupas 1900. II. Stabilite et physiologie de l'adaptation. Citation: Annales de Biologie Animale, Biochimie, Biophysique 6: 267-300 1966 Type: ARTICLE Genes: Abstract: From a 'psychrophile' Bergerac stock of C. elegans can be obtained strains genetically adapted to high temperatures (22 to 24.5C). The adaptive processes thus established can be most enduring. This appears in the following way: -a sufficiently heat acclimatized strain taken down to a low temperature (18C) does not recover, after 18 generations, the fertility rate typical of the strain kept at this low temperature throughout. -the same strain, raised again to its acclimatization temperature, always shows a fertility rate higher than that of the strain raised to this temperature for the first time. -the animals, raised again to their acclimatization temperature, quickly recover. Moreover stability depends on: -the magnitude of the alterations in the acclimatization conditions (lowest temperature and duration of breeding at this temperature). -the level of acclimatization to high temperatures of the nematodes. The stabilization of adaptive modifications finally results from a cumulative effect in the action of temperature as well as the adaptation itself. From an investigation at the cell level upon modifications in gametogenesis, we can draw the conclusion that acclimatization makes two differences: 1. the production of the abnormal figures characteristic of the senescence of the ovary is delayed in acclimatized animals. 2. non-acclimatized animals react to high temperatures by blocking meiosis, what acclimatized nematodes no longer do. High temperatures seem to induce a speeding up of the senescence phenomena. It could cumulatively act upon several generations. The acclimatization process seems to result from a new physiological balance showing itself, under constant conditions, in a slowing down of the senescence phenomena. ------------------- Key: 38 Medline: Authors: Brun JL Title: L'adaptation aux temperatures elevees chez un nematode C. elegans Maupas 1900. III. Role des facteurs autres que la temperature/ Citation: Annales de Biologie Animale, Biochimie, Biophysique 6: 439-466 1966 Type: ARTICLE Genes: Abstract: Under experimental conditions, Caenorhabditis elegans stocks kept at 18C could never survive a direct transfer to 24.5C. However, they can bear this temperature if they have been kept for many generations at intermediate temperatures: 22 - 23 - 23.5 and 24C. An experimental analysis entitles us to consider negligible the part played in this adaptation process by the nutritive medium. At intermediate temperatures, fertility increases with the duration of breeding: so does the ability to bear the next higher temperature. On another hand, the stability of the acclimatization appears to depend on the duration of breeding at a given temperature. The longer the nematodes are bred at a high temperature, the stronger the inurement is and the quicker the readaptation. Thus is undisputably defined the fundamental characteristic of the genetic adaptation of Caenorhabditis elegans: the acclimatization results from a cumulative effect in the action of temperature. This effect is very slow; at 23.5C for instance, it was only after 100 generations at least that the fertility of the animals was 4 times what it was in the first generation following the transfer from 23C. It was only after 1081 generations that the nematodes raised from 18C were able to bear 24.5C. If temperature is indeed the determining factor in the setting up and development of adaptive processes, its role may be conceived either as that of a selective agent of pre-adapted forms or as that of an instigator of adaptive modifications. Theoretically, the application of the first hypothesis is limited. As a matter of fact, the strictly autogamous fertilization of this nematode forbids, in a highly heterozygous state, to investigate upon a basis of genetic variability that might be used in order that the acclimatization process be progressively set up. In practice, a number of experimental data led us to think that this effect is almost unconceivable as far as our case is concerned. The most important of these data are: a) At any new-borne temperature, the acclimatization always begins with a short period of sensitization during which fertility decreases before progressively increasing. Now, at the minimum level it reaches, firstly the classes of high fertility are never present; secondly, there are never less than 50 per cent fertile animals. b) A positive selection of begetters is next to inefficient for it may induce either a decrease or an increase in fertility. The action of heat must therefore be considered responsible for the working out of adaptive processes. From this viewpoint, the progressive character of the modifications noticed in fertility, the fact that these modifications seem to take place in the same way at every stage of acclimatization, lead us to think that the corresponding genetic alterations are made of a sequence of stages of little moment distributed throughout the generations under experiment. The whole of our observations lead us to suppose that there is a progressive production of adapted and transmittable cytoplasmic states which would be responsible for the begetting of lineages fertile at high temperatures. ------------------- Key: 39 Medline: Authors: Brun JL Title: Influence des conditions de milieu sur la fecondite de C. elegans a diferentes temperatures. Citation: Nematologica 12: 539-556 1966 Type: ARTICLE Genes: Abstract: When grown under xenic conditions, the fertility of the free living nematode C. elegans is somewhat insensitive to the living part of the oligidic agar-medium. However, the influence of the total concentration of the inert fraction of the medium is important. For a given temperature, there is an ideal concentration, below and above which the fertility decreases significantly. This ideal concentration is much higher at elevated temperatures (23-23.5C) than at 13C. Among the constituents of the agar-medium, only the variations in concentration of the agar seemed to have an effect comparable to that of the total concentration. Variations in mineral salt and organic compound concentration showed no effect. Hence, we are led to hypothesize that changes in concentration of the agar upset the nature of the physiological exchanges between the animal and the medium by completely transforming the physical properties of the nutrient medium in which the nematode lives and reproduces. It appears possible that the increase in concentration of the medium causes a decrease in percentage of the free water of proteins. This dehydration, in turn, could account for an ------------------- Key: 41 Medline: Authors: Brun JL Title: Structure, organisation et variation du materiel genetique du nematode libre hermaphrodite autofecond C. elegans. Citation: Ann. Rep. Univ. CB/Lyon Fr : 68-78 1973 Type: REVIEW Genes: Abstract: ------------------- Key: 42 Medline: Authors: Brun JL;Lebre D Title: Influence of parental aging on the fecundity of 1st generation descendants in a self-fertilizing hermaphrodite nematode: C. elegans. Citation: C.R. des Seances de l'Academie des Sciences Serie D 266: 2149-2152 1968 Type: ARTICLE Genes: Abstract: In French. ------------------- Key: 44 Medline: Authors: Bryant C;Nicholas WL;Jantunen R Title: Some aspects of the respiratory metabolism of C. briggsae (Rhabditidae). Citation: Nematologica 13: 197-209 1967 Type: ARTICLE Genes: Abstract: A method is described for the production of large numbers of C. briggsae free from culture medium. Various aspects of the respiratory metabolism of these worms have been examined using a variety of techniques. The respiration of the worms increased rapidly as the amount of oxygen in the gaseous phase of the incubation vessels increased, until a level of 5% O2 was attained. After this no increase was observed. Cyanide in high concentrations and carbon monoxide inhibited respiration. The effect due to carbon monoxide was reduced in daylight. These substances also inhibited the development and reproduction of the worms, but the effect due to carbon monoxide was reversible. Preparations of worms subjected to sonic disruption utilised radioactive succinate, converting it to fumaric, malic, lactic and aspartic acids and to alanine. Spectrophotometric studies of washed homogenates of C. briggsae suggested the presence of pigments similar to a cytochrome b present in parasitic helminths, cytochrome c and traces of cytochrome a. Flavoprotein was detected in the washings. The implications of these results are ------------------- Key: 45 Medline: 69256313 Authors: Buecher EJ;Hansen EL Title: Yeast extract as a supplement to chemically defined medium for axenic culture of C. briggsae. Citation: Experientia 25: 656- 1969 Type: ARTICLE Genes: Abstract: Caenorhabditis briggsae, a free living soil nematode, can be grown axenically in a chemically defined medium if this is supplemented with proteinaceous materials. Only a few such materials, derived from chick embryo, bacteria, and liver have been found to be effective supplements. Since yeast cultures on agar support nematodes in vitro it seemed probable that an effective supplement could also be made from extracts of yeast. ------------------- Key: 46 Medline: Authors: Buecher EJ;Hansen EL Title: Mass culture of axenic nematodes using continuous aeration. Citation: Journal of Nematology 3: 199-200 1971 Type: ARTICLE Genes: Abstract: Biochemical and physiological studies of nematodes often require sufficient material for analysis. Two important limitations of axenic culture methods are the need for proteinaceous components and proper gas exchange. Proteinaceous supplements are tedious to prepare. Suitable gas exchange is obtained by using thin layers of medium, necessitating glassware of considerable size if large populations are desired.... ------------------- Key: 47 Medline: Authors: Buecher EJ;Hansen EL;Gottfried T Title: Yeast ribosomes as a source of growth factor for nematodes. Citation: Nematologica 15: 619-620 1969 Type: ARTICLE Genes: Abstract: There is a current interest in the study of nematodes in axenic (pure) culture. One aspect of these studies is the purification and identification of the proteinaceous growth factor added to the defined medium for maintenance of these cultures. The activation of nematode growth factor isolated from liver has been interpreted as changes in molecular structure of the soluble protein. This postulate appears to be erroneous since treatments used for activation not only cause a portion of the protein to precipitate but, in fact, the biological activity resides in the precipitate rather than in the soluble portion of ------------------- Key: 48 Medline: Authors: Buecher EJ;Hansen EL;Gottfried T Title: A nematode growth factor from baker's yeast. Citation: Journal of Nematology 2: 93-98 1970 Type: ARTICLE Genes: Abstract: An extract prepared from commercially available yeast supported maturation of the free-living nematode Caenorhabditis briggsae. The extract can be used to supplement a chemically defined medium or, after a limited dialysis, as a complete medium. Several biologically active fractions were prepared; those containing larger amounts of ribonucleic acid (RNA) had greater biological activity, the most active being a pellet resuspended after centrifugation at 30,000 X g for 30 min. This fraction could be substituted for serum in a medium which supports the maturation of the animal parasites Trichinella spiralis and Hymenolepis nana. Addition of protamine sulfate decreased the RNA content, leaving inactive protein fractions which could be reactivated by specific treatments that caused protein precipitation. It is postulated that biological activity is associated with protein sedimented with ribosomes. ------------------- Key: 49 Medline: 66132686 Authors: Buecher EJ;Hansen E;Yarwood EA Title: Ficoll activation of a protein essential for maturation of the free-living nematode Caenorhabditis briggsae. Citation: Proc. Society for Experimental Biology & Medicine 121: 390-393 1966 Type: ARTICLE Genes: Abstract: Previous work with axenic culture of the free living nematode, Caenorhabditis briggsae, led to isolation of a heat labile fraction from liver which was essential for maintenance of these cultures in an otherwise chemically defined medium. Subsequently, this fraction has been further separated by chromatography on hydroxylapatite. The globulin recovered has the interesting property of being "activated", that is, certain specific treatments increased the biological activity 30-fold. This phenomenon may have a bearing on the availability of proteinaceous materials in biological systems. This proteinaceous growth factor is present in most animal tissues as well as in bacteria. Preliminary studies show that the material is effective in a wide range of biological systems. ------------------- Key: 50 Medline: Authors: Buecher EJ;Hansen EL;Yarwood EA Title: Growth of nematodes in defined medium containing hemin and supplemented with commercially available proteins. Citation: Nematologica 16: 403-409 1970 Type: ARTICLE Genes: Abstract: It has been shown that several free-living nematodes, the insect parasite Neoaplectana carpocapsae, and the plant parasite Aphelenchus avenae, will grow and reproduce in axenic culture in defined medium containing hemin and supplemented with y-globulin. In addition, other commercially available proteins were tested with Caenorhabditis briggsae and A. avenae. Activity was less than that of liver growth factor. Proper precipitation of the protein was important in determining the effectiveness of the supplements for C. briggsae. Hemin added to growth factor had no stimulatory effect. These results extend the range of proteins suitable as supplements for growing nematodes. ------------------- Key: 51 Medline: Authors: Buecher EJ;Hansen EL;Yarwood EA Title: Cultivation of C. briggsae and Turbatrix aceti with defined proteins. Citation: Journal of Nematology 3: 89-90 1971 Type: ARTICLE Genes: Abstract: Following the report that addition of hemin and cholesterol allowed reproduction of Caenorhabditis briggsae in media containing autoclaved bacteria, we showed that by addition of hemin certain commercially available proteins could be used successfully in the culture medium. We now report that when both hemin and cholesterol are added, certain completely characterized proteins are effective supplements to media for cultivation of C. briggsae and Turbatrix ------------------- Key: 52 Medline: 70042388 Authors: Buecher EJ;Perez-Mendez G;Hansen EL Title: The role of precipitation during activation treatments of growth factor for C. briggsae. Citation: Proc. Society for Experimental Biology & Medicine 132: 724-728 1969 Type: ARTICLE Genes: Abstract: Axenic cultures of Caenorhabditis briggsae, a free living hermaphroditic nematode, have been maintained in chemically defined media supplemented with a proteinaceous growth factor. It has been found that this factor was increased in effectiveness as much as thirtyfold by treatment with a variety of specific processes termed "activation". An explanation for the mechanism of this increase has been sought. It had previously been observed that the complete medium containing Ficoll-activated growth factor lost activity upon filtration suggesting that a partially precipitated material might be of importance in nutrition of the nematode. It had also been observed that when other methods of activation were used there was a noticeable increase in turbidity. We therefore attempted to determine if precipitation in the medium occurred in all activation processes, and if so, whether the precipitated portion of the protein carried the biological activity. The specificity of growth factor from this point of view was examined. ------------------- Key: 53 Medline: 75140489 Authors: Byerly L;Cassada RC;Russell RL Title: Machine for rapidly counting and measuring the size of small nematodes. Citation: Review of Scientific Instruments 46: 517-522 1975 Type: ARTICLE Genes: Abstract: A machine has been developed to accurately count and size large populations of the small nematode Caenorhabditis elegans with minimal effort. Like the related Coulter counter, this machine detects the change in electrical current which a particle (nematode) produces as it passes between two electrodes in a small transducer. Despite the use of alternating current, detailed analysis shows that detection is based primarily on resistance changes. The machine also employs a sheathed-flow system to orient the long thin animals reproducibly in the transducer, so that resistance changes correspond directly to animal size. Accurate, non-destructive measurements of live nematodes which have a 20-fold length-to-width ratio and vary over a 10*3 range in volume can be achieved at a counting rate of 10*3 per minute with 1% coincidence. Sources of measurement errors have been identified and controlled or eliminated. The machine has been calibrated against the optically measured lengths of nematodes in all stages of the life cycle. ------------------- Key: 54 Medline: 76235893 Authors: Byerly L;Cassada RC;Russell RL Title: The life cycle of the nematode C. elegans. I. Wild type growth and reproduction. Citation: Developmental Biology 51: 23-33 1976 Type: ARTICLE Genes: Abstract: The growth and reproduction of the small nematode Caenorhabditis elegans has been studied using an electronic nematode counter recently developed in our laboratory. At 20C, the usual growth temperature, size increases in a smooth sigmoidal manner with time, linear growth being the most rapid around the time of the fourth molt and nearly ceasing by the end of the period of egg-laying. Growth of populations is highly synchronous; the small residual size heterogeneity is maximal at about the time of maximal growth. The four molts do not involve major interruption of growth, but they do entail slight shape changes (elongating upon escape from the old cuticle). Egg-laying begins shortly after the fourth molt, the rate rising rapidly at first, then more gradually to a peak followed by a relatively rapid fall. Comparable measurements at 16 and 25C establish that these are acceptable limit temperatures for work with temperature-sensitive mutants, although egg yield is somewhat reduced and the kinetics of egg-laying are altered at 25C. Developmental chronologies for all three temperatures are presented. ------------------- Key: 55 Medline: 76235894 Authors: Byerly L;Scherer S;Russell RL Title: The life cycle of the nematode C. elegans. II. A simplified method for mutant characterization. Citation: Developmental Biology 51: 34-48 1976 Type: ARTICLE Genes: dpy-10 dpy-13 tax-1 tax-4 Abstract: A simple method for characterizing the development and reproduction of mutant strains of the small nematode Caenorhabditis elegans has been developed. "3-egg" populations of nematode, started with three synchronously laid eggs and allowed to develop undisturbed for about two generations, are measured on the electronic nematode counter, and the resulting size distributions are interpreted by a computer. The computer compares the observed distribution to an expected distribution, generated by assuming the developmental curves previously measured for the wild-type C. elegans; if the distributions do not agree, the computer independently varies scale factors for developmental rate, size, egg-laying rate, and spread until the expected distribution best approximates the observed one. The resulting factors quantify any mutant defect of growth or reproduction, and the poorness of fit tells how greatly the mutant's development differs from that of the wild-type in ways other than those allowed for by the four scale changes. The computer program is shown to be able to fit wild-type C. elegans 3-egg populations grown for various lengths of time at 20C. Three-egg populations of wild-type animals grown at 16 and 25C are fitted by the computer and give altered developmental parameters consistent with those previously measured by more direct means. Nine behavioral and morphological mutants have been analyzed by this method. All show some developmental alterations from the wild-type. Fertility seems to be more adversely affected than growth. One mutant has been studied in more detail to determine the ------------------- Key: 58 Medline: 76044301 Authors: Cassada RC;Russell RL Title: The dauerlarva, a post-embryonic developmental variant of the nematode C. elegans. Citation: Developmental Biology 46: 326-342 1975 Type: ARTICLE Genes: Abstract: In the postembryological development of the free-living nematode Caenorhabditis elegans, a morphologically recognizable, nongrowing stage, called the dauerlarva, may arise. Using synchronous populations and following growth and molting, it has been shown that the dauerlarva is formed by a facultative, reversible arrest at a specific point in the life cycle, the second of four cuticle molts, in response to external conditions. At each molt a normal animal passes through "lethargus", a stage in which feeding and locomotion are transiently arrested. In the dauerlarva stage, feeding is arrested indefinitely and locomotion is markedly reduced. A simple quantitative assay, based on the exceptional resistance of dauerlarvae to sodium dodecyl sulfate (SDS), has been developed to study dauerlarva formation and its reversal. The SDS resistance of dauerlarvae requires both non-feeding and an especially impermeable cuticle. Dauerlarva formation can be efficiently induced by limiting the concentration of bacteria (the food supply), but not by complete starvation. Quantitative recovery to normal development can be induced by transfer to fresh medium with excess bacteria. Simpler stimuli can elicit recovery at slower rates, the principal factors besides nutrition being optimal ionic and osmotic conditions and a noninhibitory concentration of animals. There are identifiable stages in recovery, beginning with a resumption of feeding. The cuticle, ultrastructurally very different from normal cuticle, is shed at the next molt, after which development appears as normal. A temperature-sensitive mutant, which forms dauerlarvae at high temperature despite the presence of abundant food, is described, and the use of dauerlarvae for futher mutant isolation is discussed. ------------------- Key: 60 Medline: Authors: Castillo JM;Kisiel MJ;Zuckerman BM Title: Studies on the effects of 2 procaine preparations on C. briggsae. Citation: Nematologica 21: 401-407 1975 Type: ARTICLE Genes: Abstract: Concentrations below 0.36 mM procaine had no significant effect on several developmental parameters of Caenorhabditis briggsae; growth, fecundity, time of inception of the reproductive period and duration of the reproductive period. In old C. briggsae, significant differences in osmotic fragility occurred to concentrations as low as 0.18 mM. Using cationized ferritin for evaluating membrane negative surface charge, at 33 mM partial lysis of the cuticle surface membrane occurred and negative charge was lost from unlysed areas. At 7.2 mM the negative charge was present in some areas of the membrane but not in others, while at 0.18 mM negative charge density did not differ significantly from that of untreated nematodes. Since the osmotic fragility effect persisted at procaine concentrations which did not affect surface charge, these results suggest two separate modes of action ------------------- Key: 61 Medline: Authors: Cayrol JC;Brun J Title: Etude, a differentes temperatures, de l'activite predatrice de quelques champignons nematophages vis-a-vis du nematode C. elegans/ Citation: Revue de Zoologie Agricole et de Pathologie Vegetale 74: 139-146 1975 Type: ARTICLE Genes: Abstract: In French. ------------------- Key: 63 Medline: Authors: Cayrol JC;Dreyfus B Title: Etudes preliminaires sur les relations entre nematodes libres et bacteri es dans le sol. Citation: C.R. des Seances de la Societe Biologie 169: 166-172 1975 Type: ARTICLE Genes: Abstract: At first we have proved that the free-living nematodes are unable to live in axenic conditions without bacteria. Then we have demonstrated that each species of nematode is associated with a typical bacterial complex. It has been later noticed that the nutritious properties of the bacteria greatly change for each species of nematode: some of them give to the animal an abundant food (favourable bacteria). Other provide only a poor food and are not favourable for the nematodes development (tolerant bacteria). Lastly, others are unable to provide the indispensable nutritious factors and the nematodes die (unfavourable bacteria). The formation of a bacterial complex associated with each species of nematode seems in relation with the nutritious properties of the different ------------------- Key: 65 Medline: 80006803 Authors: Chalfie M;Thomson JN Title: Organization of neuronal microtubules in the nematode C. elegans. Citation: Journal of Cell Biology 82: 278-289 1979 Type: ARTICLE Genes: Abstract: We have studied the organization of microtubules in neurons of the nematode Caenorhabditis elegans. Six neurons, which we call the microtubule cells, contain bundles of darkly staining microtubules which can be followed easily in serial-section electron micrographs. Reconstruction of individual microtubules in these cells indicates that most, if not all, microtubules are short compared with the length of the cell process. Average microtubule length varies characteristically with cell type. The arrangement of microtubules gives an overall polarity to each bundle: the distal ends of the microtubules are on the outside of the bundle, whereas the proximal ends are preferentially inside. The distal and proximal ends each have a characteristic appearance indicating that these microtubules may have a polarity of their own. Short microtubules in processes of other neurons in C. elegans ------------------- Key: 66 Medline: 79116354 Authors: Cheng AC;Lu NC;Briggs GM;Stokstad ELR Title: Effect of particulate materials on population growth of the free living nematode C. briggsae. Citation: Proc. Society for Experimental Biology & Medicine 160: 203-207 1979 Type: ARTICLE Genes: Abstract: Recent investigations have shown that ingestion of particulate material has promoted population growth of amoebas and ciliates. The authors have suggested that particulate material in nutrient media induces formation of food vacuoles and thus permits faster uptake of nutrients. Previous work with an axenic culture of free-living nematodes demonstrated that particulate protein stimulates earlier maturation of Caenorhabditis briggsae. However, when polystyrene latex beads were added to the chemically defined medium in place of the particulate protein, no stimulation was observed. Later, Vanfleteren observed larger population increases with acid-precipitated heme and also proposed the idea that acid-precipitated heme can replace the particulate protein. This study of the effects of particulate material on population growth of C. briggsae was prompted by the observation that population growth was greater when the organism was cultured in a turbid medium prepared by the addition of a separately heat-sterilized salt mixture which had become turbid on autoclaving, than when they were cultured in a clear medium prepared by the addition of a separately sterile-filtered salt mixture which remained clear after Millipore filtering. This led to the hypothesis that the particles themselves could stimulate population growth and that the particulate material does not necessarily have to be a protein moiety. Experiments were conducted to examine the effect of various inert particles on population growth, and to determine whether there is any particular size or size range that is most stimulatory. Finally, we wished to see if various particulates could replace casamino acids, which are commonly used in our laboratory as a source of proteinaceous growth factor(s) for the test organism. ------------------- Key: 67 Medline: Authors: Chitwood BG Title: Studies on some physiological functions and morphological characters of Rhabditis (Rhabditidae, Nematoda). Citation: Journal of Morphology 49: 251-275 1930 Type: REVIEW Genes: Abstract: Intravitam stains were used to determine the functions of several organs in two species of nemas (Rhabditis strongyloides and Rhabditis elongata). The organs were also studied in section. From the results obtained it is concluded that the amphids are not excretory in function, but more probably sensory, for definite connections were observed to extend to the nerve ring. No migratory cells, such as those described by Stefanski, were seen. The phasmids stained with all intravitam stains used, but were never observed to secrete. It seems doubtful that they serve as excretory organs. The excretory system was seen to consist of a typical X system. Actual excretion was observed. Deirids were seen for the first time in both species. Oesophageal glands were also described. A study was made of the structure of the intestinal cells, rectal glands, and anal muscles. Attention was called to the fact that there are two kinds of ejaculatory glands, one of which probably serves as a 'cement gland', while the function of the other is still in doubt. ------------------- Key: 69 Medline: 76060401 Authors: Colonna WJ;McFadden BA Title: Isocitrate lyase from parasitic and free living nematodes. Citation: Archives of Biochemistry & Biophysics 170: 608-619 1975 Type: ARTICLE Genes: Abstract: Isocitrate lyase and malate synthase were demonstrated in the soil nematode Caenorhabditis elegans and the isocitrate lyase partially characterized and compared with that from embryos of the hog roundworm Ascaris lumbricoides. Both enzymes have similar pH optima, molecular weights and K(m)s for isocitrate. Isocitrate lyase from A. lumbricoides consists of a single species of pI 6.6; the lyase from C. elegans consists of a major fraction of pI 5.1 and two lesser species of pI 4.4 and 4.1, suggestive of multiple enzymes. Oxalate, a reversible inhibitor, protects isocitrate lyase from both sources against thermal inactivation; protection is better in the case of the Ascaris enzyme. Antibodies to highly purified C. elegans isocitrate lyase inhibit catalysis by the enzyme from either nematode and form precipitin bands in gels with lyase-containing extracts from both organisms, implying common evolutionary ancestry. Isocitrate lyase from C. elegans, unlike that from A. lumbricoides, can be detected in adult forms of the nematode. ------------------- Key: 70 Medline: Authors: Cooper AF;Van Gundy SD Title: Senescence, quiescence, and cryptobiosis. Citation: "Plant Parasitic Nematodes, Volume II. Cytogenetics, Host-Parasite Interactions, and Physiology." Zuckerman BM, Mai WF and Rohde RA (eds), Academic Press, NY. 2: 297-315 1971 Type: REVIEW Genes: Abstract: The words senescence, quiescence, and cryptobiosis describe quantitatively decreasing levels (time rates of change) of metabolic activity which may occur during the aging of an organism. Which mode is operative depends upon the metabolic status and adaptability of the individual and upon the kinds and intensities of environmental stress. Senescence ("normal" aging) is characterized by an average pattern of metabolic activities whereby the life cycle can be completed in a given environment. When the environment balance shifts unfavorably, some organisms experience a metabolic "slowdown" called quiescence: movement slows or ceases, and the normal sequence of life cycle functions is delayed. With further increase or continuation of environmental stress a few biological systems enter cryptobiosis which is a "shutdown" of metabolism to levels not detectable by currently available biochemical methods or physical instrumentation. Structural integrity is maintained (or only slowly declines) and the potential for resumption of quiescence, motility, and even the normal patterns of senescence is retained, often for extended periods of time.... ------------------- Key: 72 Medline: Authors: Cooper AF Jr;Van Gundy SD Title: Metabolism of glycogen and neutral lipids by Aphelenchus avenae and Caenorhabditis sp. in aerobic, microaerobic, and anaerobic environments. Citation: Journal of Nematology 2: 305-315 1970 Type: ARTICLE Genes: Abstract: Starving Aphelenchus avenae survived 3-4 weeks in microaerobic and anaerobic environments, but Caenorhabditis sp. survived less than 80 hr. Aerobically, both nematodes metabolize neutral lipid reserves: there was no microaerobic (<5% 02) or anaerobic neutral lipid catabolism. Early in anaerobiosis both nematodes utilized endogenous glycogen. Caenorhabditis sp. depleted the glycogen and died. A. avenae under oxygen stress longer than 120 hr entered cryptobiosis, during which there was neither measurable O2 uptake nor glycogen or neutral lipid utilization. Only when re-aerated, did A. avenae recover and resume "normal" metabolism. ------------------- Key: 73 Medline: Authors: Cooper AF;Van Gundy SD Title: Ethanol production and utilization by Aphelenchus avenae and Caenorhabditis sp. Citation: Journal of Nematology 3: 205-214 1971 Type: ARTICLE Genes: Abstract: In microaerobic and anaerobic environments the principle glycolytic end-product of A. avenae and Caenorhabditis sp. was lactic acid during the first 12-16 hr, after which it was ethanol. Upon return to aerobiosis, 11C-labeled ethanol in the medium was utilized by the nematodes; 14CO2 and some 14C-labeled glycogen was detected. Total dry weight loss of nonfeeding nematodes was 25% greater in the absence of alcohol than in the presence of ethanol or n-propanol. Physical movement and respiration increased and reproduction was extended by alcohol in the bathing ------------------- Key: 74 Medline: Authors: Cooper AF Jr;Van Gundy SD;Stolzy LH Title: Nematode reproduction in environments of fluctuating aeration. Citation: Journal of Nematology 2: 182-188 1970 Type: ARTICLE Genes: Abstract: Reproduction of Aphelenchus avenae, reared on Rhizoctonia solani growing on steamed wheat seeds and Caenorhabditis sp., reared on a mixed bacterial culture grown on oatmeal, was significantly reduced at 5% oxygen and inhibited at 4% oxygen and below. Aeration ranging from atmospheric air (21%) to 10% oxygen had no effect on reproduction. Close interval (5 days or less) fluctuations between high and low oxygen concentrations, inhibited population buildup of Hemicycliophora arenaria on tomato in soil, and of A. avenae and Caenorhabditis sp. in vitro. In soil tests with H. arenaria exposed to 12 hr of nitrogen every three days (in air) inhibited the rate of buildup compared to controls maintained in continuous air. With the in vitro studies, as little as 4 hr nitrogen every 3 days (stored in air) significantly influenced the population numbers. ------------------- Key: 75 Medline: Authors: Croll NA Title: Components and patterns in the behaviour of the nematode C. elegans. Citation: Journal of Zoology 176: 159-176 1975 Type: ARTICLE Genes: Abstract: The behavioural activities during movement, feeding and defaecation have been recorded and measured in adult females of Caenorhabditis elegans. The postures and components of recognizable wave forms are described. Stress has been laid on the machanism of antagonistic interaction of backward and forward movement, and the rates and characteristics of "spontaneous" and "induced" reversal periods. During feeding, rapid rates of pharyngeal activity are invariably related to low rates of somatic muscle wave propagation. Head oscillations are considered to be separate events not directly linked with feeding or foraging. The combination of certain wave forms, together with other measurements have been used to develop a hypothesis to describe a co-ordinating mechanism to the nematode level of organization. ------------------- Key: 76 Medline: 75185266 Authors: Croll NA Title: Indolealkylamines in the coordination of nematode behavioral activities. Citation: Canadian Journal of Zoology 53: 894-903 1975 Type: ARTICLE Genes: Abstract: Nematode movements result from spontaneous myogenic depolarizations, neuromuscular coordination, and localized hydrostatic changes. These components are integrated into activities which are mutually exclusive or interdependent. Nervous connection is not known between all the organ systems, and the pharynx and female tract are somewhat autonomous. This problem is discussed, as is the limitation of a theory involving only cholinergic transmission. Serotonin, 5-hydroxytryptophan (5HTP), and epinephrine were all found to induce rapid and prolonged contractions in the female vagina/vulva of Caenorhabditis elegans, Aphelenchus avenae, Panagrellus redivivus, and Oswaldocruzia filiformis. It also caused spicule extension in males of P. redivivus. The responses are fully described together with dose-response data and the effect of adult age. The potential significance of indolealkylamines in nematode behavioral coordination is discussed, together with the relevance of anthelmintic formulation and the basis of immunological rejection. ------------------- Key: 77 Medline: Authors: Croll NA Title: When C. elegans (Nematoda: Rhabditidae) bumps into a bead. Citation: Canadian Journal of Zoology 54: 566-570 1976 Type: ARTICLE Genes: Abstract: When C. elegans bumps into a bead, it stops moving, withdraws a short distance, and then resumes forward movement, often in a new direction. This series of events has been analysed in its constituent parts and the features making up the 'stimulus' have been compared numerically with those making up the 'response'. No significant correlations were found that support the interpretation that this is a simple stimulus-response phenomenon. It is argued that the data support an alternative view that when forward movement is interrupted, C. elegans is primed to undergo a short, rapid reversal and that this is not mediated through sensory mechanoreceptors. ------------------- Key: 78 Medline: Authors: Croll NA Title: Behavioral coordination of nematodes. Citation: "The Organization of Nematodes." Croll NA (ed), Academic Press, NY. : 343-364 1976 Type: REVIEW Genes: Abstract: ------------------- Key: 79 Medline: Authors: Croll NA Title: Sensory mechanisms in nematodes. Citation: Annual Review of Phytopathology 15: 75-89 1977 Type: REVIEW Genes: cat-1 cat-2 unc-5 unc-30 Abstract: There have recently been unprecedented advances in our knowledge of senses and responses in nematodes. As this review is being published data on sensory mechanisms in nematodes continue to flood in from laboratories all over the world. Developments have not come directly from electrophysiology, but rather indirectly, through detailed neuroanatomy and through interpretations based on the behavior of the entire organism. Studies of free-living bacteriophagous species Caenorhabditis elegans have led to many of these advances and are the basis for a major part of this review.... ------------------- Key: 80 Medline: Authors: Croll NA;Smith JM Title: Integrated behaviour in the feeding phase of C. elegans (Nematoda). Citation: Journal of Zoology 184: 507-517 1978 Type: ARTICLE Genes: Abstract: Caenorhabditis elegans spends most of its life feeding. When feeding, it moves only short distances but intestinal contents are moved to and fro and thus mixed. The nematodes also defaecate and lay eggs during the feeding phase in bacterial culture. Defaecation is one of a series of events which causes the forward and backward movement of intestinal contents. These rhythmic movements, once initiated, appear to be controlled by a pacemaker and are unrelated to feeding rates. Oviposition is associated with movements of the genital tract and it can occur at any posture and does not influence the rate of other activities. After food-deprivation, C. elegans shows no measureable hunger response on being returned to bacteria. Experiments with excised parts of worms showed that isolated anterior ends will feed both in and out of bacteria and move forward and backward. Isolated posterior halves without a pharynx or circumpharyngeal commissure ------------------- Key: 81 Medline: 78024049 Authors: Croll NA;Smith JM;Zuckerman BM Title: The aging process of the nematode C. elegans in bacterial and axenic culture. Citation: Experimental Aging Research 3: 175-189 1977 Type: ARTICLE Genes: Abstract: While much is known of the morphological and some physiological changes which occur during the aging of Caenorhabditis elegans, little attempt has been made to measure the changes in behavior. Wild type C. elegans (var. Bristol) were cultured axenically, individually observed each day for 15 minutes and their behavioural actions recorded on a multi-channel event recorder or on a video tape recorder of a closed circuit TV. Particular attention was paid to the rate of backwardly directed somatic waves, pharyngeal bulb pulsations, the interval between defecations and oviposition. C. elegans lived significantly longer in axenic culture than in bacteria. A gradual linear decline occurred in the rate of backward waves between maturation (day 4) and death (day 20) for those worms in axenic culture. In striking contrast, the mean maximum rate of pharyngeal bulb pulsations maintained a plateau from day 4 to 18, while the mean interval between defecations doubled from 60 sec (days 4 to 8) to 120 sec (days 10-20). These results are discussed in the context of nematode coordination and the mechanisms of aging. ------------------- Key: 82 Medline: 79086923 Authors: Culotti JG;Russell RL Title: Osmotic avoidance defective mutants of the nematode C. elegans. Citation: Genetics 90: 243-256 1978 Type: ARTICLE Genes: che-1 che-3 daf-10 osm-1 osm-3 osm-5 osm-6 Abstract: A wild-type strain of the nematode Caenorhabditis elegans has been shown to avoid high concentrations of a number of sugars and salts. Individual and population assays for this response were developed and mutants were selected for their inability to avoid high concentrations of fructose or NaCl. Seven nonavoiding mutants representing six complementation groups were isolated and characterized. Genetic studies indicate that the mutants each carry a single recessive mutation responsible for the defective osmotic avoidance behavior. The map locations of the six complementation groups identified by these mutations have been determined. Mutants isolated for their inability to avoid fructose are also unable to avoid NaCl and vice versa. The mutants move normally, exhibit normal touch sensitivity, and, like wild type, follow isotherms in a radial thermal gradient. All of the mutants are at least partially defective in the attraction to sodium chloride exhibited by wild type. None of the mutants is temperature sensitive, and all exhibit defective osmotic avoidance behavior as young L1 larvae. Preliminary anatomical studies indicate selective sensory neuron changes in at ------------------- Key: 83 Medline: Authors: Delavault R Title: La teneur en acide desoxyribonucleique des noyaux sexuels chez un Rhabditis hermaphrodite. Citation: C.R. des Seances de l'Academie des Sciences Serie D 234: 884-885 1952 Type: ARTICLE Genes: Abstract: In French. ------------------- Key: 84 Medline: Authors: Delavault R Title: Etude cytologique des acides nucleiques chez un nematode libre (Rhabditis elegans Maupas 1900). Citation: Archiv. Anat. Micro. Morphol. Exp. 41: 41-68 1952 Type: ARTICLE Genes: Abstract: In French. ------------------- Key: 85 Medline: Authors: Delavault R Title: Croissance des ovotestis puis des ovaires chez un nematode libre hermaphrodite: C. elegans Maupas 1900. Citation: Bulletin de la Societe Zoologique de France : 321-325 1957 Type: ARTICLE Genes: Abstract: In French. ------------------- Key: 86 Medline: Authors: Delavault R Title: Developpement, croissance et fonctionnement des glandes genitales chez les nematodes libres. Citation: Archives de Zoologie Experimentale et Generale 97: 109-208 1959 Type: ARTICLE Genes: Abstract: In French. ------------------- Key: 87 Medline: Authors: DeNiro MJ;Epstein S Title: Influence of diet on the distribution of carbon isotopes in animals. Citation: Geochimica et Cosmochimica Acta 42: 495-506 1978 Type: ARTICLE Genes: Abstract: The influence of diet on the distribution of carbon isotopes in animals was investigated by analyzing animals grown in the laboratory on diets of constant carbon isotopic composition. The isotopic composition of the whole body of an animal reflects the isotopic composition of its diet, but the animal is on average enriched in *13C by about 1% relative to the diet. In three of the four cases examined, the 13C enrichment of the whole body relative to the diet is balanced by a 13C depletion of the respired CO2. The isotopic relationships between the whole bodies of animals and their diets are similar for different species raised on the same diet and for the same species raised on different diets. However, the *13C values of whole bodies of individuals of a species raised on the same diet may differ by up to 2%. The relationship between the 13C/12C ratio of a tissue and the 13C/12C ratio of the diet depends both on the type of tissue and on the nature of the diet. Many of the isotopic relationships among the major biochemical fractions, namely the lipid, carbohydrate and protein fractions, are qualitatively preserved as diet carbon is incorporated into the animal. However, the difference between the *13C values of a biochemical fraction in an animal and in its diet may be as large as 3%. The *13C values of the biochemical components collagen, chitin and the insoluble organic fraction of shells, all of which are often preserved in fossil material, are related to the isotopic composition of the diet. These results indicate that it will be possible to perform dietary analysis based on the determination of the 13C/12C ratio of animal carbon. Analysis of the total animal carbon will in most cases provide a better measure of diet than the analysis of individual tissues, biochemical fractions, or biochemical components. The limits of accuracy of this method will generally restrict its application to situations in which the diet is derived from sources with relatively large differences in their *13C values, such as terrestrial vs aquatic organisms or C3 vs C4 plants. This method should be applicable to fossil ------------------- Key: 88 Medline: 78116013 Authors: Deppe U;Schierenberg E;Cole T;Krieg C;Schmitt D;Yoder B;von Ehrenstein G Title: Cell lineages of embryo of nematode C. elegans. Citation: Proceedings of the National Academy of Sciences USA 75: 376-380 1978 Type: ARTICLE Genes: Abstract: Embryogenesis of the free-living soil nematode Caenorhabditis elegans produces a juvenile having about 550 cells at hatching. We have determined the lineages of 182 cells by tracing the divisions of individual cells in living embryos. An invariant pattern of cleavage divisions of the egg generates a set of stem cells. These stem cells are the founders of six stem cell lineages. Each lineage has its own clock-i.e., an autonomous rhythm of synchronous cell divisions. The rhythms are maintained in spite of extensive cellular rearrangement. The rate and the orientation of the cell divisions of the cell lineages are essentially invariant among individuals. Thus, the destiny of cells seems to depend primarily on their lineage history. The anterior position of the site of origin of the stem cells in the egg relates to the rate of the cell cycle clock, suggesting intracellular preprogramming of the uncleaved egg. We used a technique that allows normal embryogenesis, from the fertilized egg to hatching, outside the parent under a cover glass. Embryogenesis was followed microscopically with Nomarski interference optics and high-resolution vidoe recording. ------------------- Key: 89 Medline: Authors: Deubert KH;Zuckerman BM Title: The histochemical demonstration of cytochrome oxidase in fresh-frozen sections of nematodes. Citation: Nematologica 14: 453-455 1968 Type: ARTICLE Genes: Abstract: Histochemical procedures for the demonstration of cytochrome oxidase in fresh-frozen sections prepared from nematodes are described. ------------------- Key: 90 Medline: 72030103 Authors: Dion M;Brun JL Title: Genetic mapping of the free-living nematode C. elegans Maupas 1900, var. Bergerac. I. Study of two dwarf mutants. Citation: Molecular & General Genetics 112: 133-151 1971 Type: ARTICLE Genes: Abstract: The genetic study of two dwarf and spontaneous mutants of the diploid free-living nematode C. elegans has been realised according to the particular methods imposed by the unbalanced self-fertilizing hermaphroditism usual to this animal by the absence of fertility of the male mutants. By combining crosses of hermaphrodite homozygous dwarfs with exceptional heterozygous males and the study of the progeny by automixis of the hermaphrodite hybrids, it can be shown: 1. Dwarfism in each mutant strain is a recessive and single factor character. 2. Characteristics of the two types of mutants are controlled by two different genes which are independant (phenotype ratio of complementary hermaphrodites progeny: 9N/7n) and not sex-linked. 3. Expression of dwarfness requires that at least one gene should be double recessive. The embryonic determination of dwarfness could correspond to a perturbation of the eutelie characteristic of the nematode. ------------------- Key: 92 Medline: Authors: Dougherty EC Title: Sterile pieces of chick embryo as a medium for the indefinite cultivation of Rhabditis briggsae Dougherty & Nigon, 1949 (Nematoda: Rhabditidae). Citation: Science 111: 2880- 1950 Type: ARTICLE Genes: Abstract: During the past eight months (i.e., since December, 1948) it has been possible to rear successive generations of a rhabditid nematode, Rhabditis briggsae, on sterile pieces of chick embryo. This medium may be termed "axenic" (without strange [life]), inasmuch as the pieces of chick embryo are nonliving. Moreover, in some cases the pieces have been frozen, thawed, and then used; in others they have undergone a certain amount of autolysis before use by reason of being stored at 4C for up to a month's time..... ------------------- Key: 93 Medline: Authors: Dougherty EC Title: The axenic cultivation of Rhabditis briggsae Dougherty & Nigon, 1949 (Nematoda: Rhabditidae) II. Some sources and characteristics of "factor Rb". Citation: Experimental Parasitology 1: 34-45 1951 Type: ARTICLE Genes: Abstract: It is obvious that success in the cultivation in vitro of parasitic helminths would open up important new experimental approaches in the fight against diseases caused by them, but it is also obvious that such cultivation presents many difficulties. The study of free-living forms that can be grown axenically (i.e., free of other living forms) may well provide important clues to the problem of the growing of parasites free from their hosts. Moreover, such free-living forms constitute potentially valuable subjects for experiments on helminth metabolism, with such practical consequences as the testing ------------------- Key: 94 Medline: Authors: Dougherty EC Title: The axenic cultivation of Rhabditis briggsae Dougherty & Nigon, 1949 (Nematoda: Rhabditidae) III. Liver preparation with various supplementations. Citation: Journal of Parasitology 39: 371-380 1953 Type: ARTICLE Genes: Abstract: The axenic cultivation (i.e., growth in the absence of other living organisms) of the free-living soil nematode, Rhabditis briggsae, requires a complex medium including one or more heat-labile, protein-like substances which have been termed "factor Rb". It has been shown that factor Rb can be provided by preparations from liver or chick embryo juice or by human plasma or certain of its fractions. Moreover, it has recently been reported in abstract that a dialysed fraction of buffered aqueous liver extract will support excellent growth of R. briggsae when supplemented with known substances only. The present paper reports the results of recent studies on the nature and properties of factor Rb in liver protein and on various supplementations of certain unheated liver preparations as media for R. briggsae. Aqueous, unheated horse liver extract (hereinafter referred to as LE), prepared by centrifuging liver homogenate and taking supernatant, has been treated in various ways to provide information on the properties of factor Rb. Such preparations have been variously supplemented and tested as media for the axenic cultivation of R. briggsae. The principle supplementation used has been the supernatant (ALE) from autoclaved LE. Both partly and completely defined supplementations have also been employed. From these studies some advance has been made in the direction of a completely defined medium for R. ------------------- Key: 95 Medline: Authors: Dougherty EC Title: The genera of the subfamily Rhabditinae Micolitzky 1922 (Nematoda). Citation: G.S. Thepar Commemoration Volume (Lucknow) : 69-76 1953 Type: ARTICLE Genes: Abstract: ------------------- Key: 96 Medline: Authors: Dougherty EC Title: The genera & species of the subfamily Rhabditinae Micoletzky, 1922(Nematoda): A nomenclatorial analysis-including an addendum on the composition of the family Rhabditidae Orley, 18 Citation: Journal of Helminthology 29: 105-152 1955 Type: REVIEW Genes: Abstract: Osche (1952) has recently published a sorely needed, comprehensive revision of the genus Rhabditis Dujardin [1844] (sensu lato) including detailed study of certain features of the cephalic end, especially of the stoma or mouth cavity. For some time to come his study will surely be the point of departure for morpholigical and systematic work on the group. On the basis principally of the structure of the metastom (a subdivision of the stoma) and of the esophagus, he recognizes some eight subgenera in the genus Rhabditis, which are as follows: Rhabditis Dujardin [1844] (sensu stricto), Choriorhabditis Osche, 1952, Telorhabditis Osche, 1952, Caenorhabditis Osche, 1952, Mesorhabditis Osche, 1952, Teratorhabditis Oshce, 1952, Protorhabditis Osche, 1952, and Parasitorhabditis Fuch, 1937. For all of these save the last he lists the species recognized by him. For a revision of Parasitorhabditis he refers to an unpublished manuscript by Ruhm..... ------------------- Key: 97 Medline: Authors: Dougherty EC Title: Introduction to axenic culture of invertebrate metazoa: A goal*. Citation: Annals of the New York Academy of Sciences 77: 27-54 1959 Type: REVIEW Genes: Abstract: As consulting editor, I saw and now take the opportunity to amalgamate concepts scattered in the papers that follow. My hope also is to bring a certain unity to the heterogeneous studies contributed by the imaginative and resourceful workers who created the program of the conference on which this monograph is based. Axenic cultivation, the rearing of one or more individuals of a single species on a nonliving medium, dominates microbiology. Axenic cultures, usually referred to as "pure cultures", are fundamental to identification of many protists (bacteria, algae, fungi, and protozoa) and to their exploitation in research... ------------------- Key: 98 Medline: Authors: Dougherty EC Title: Cultivation of Aschelminths, especially Rhabditid Citation: "Nematology." Sasser JN and Jenkins WR (eds), University of North Carolina Press, Chapel Hill. : 297-318 1960 Type: REVIEW Genes: Abstract: For the purpose of the present chapter the noun 'cultivation' is to be taken as the maintenance, in the laboratory, of a population of organisms belonging to a desired species through successive generations and subcultures over a prolonged period of time (weeks, months, or years). This is a deliberate restriction of the term. The noun 'culture' is most aptly used for a population within a circumscribed vessel or container (test-tube, Petri dish, U.S. Bureau of Plant Industry watch glass, etc.); it is also used in a looser, more general way (as "in culture") to cover conditions of substantial growth whether or not leading to cultivation in the strict sense ------------------- Key: 100 Medline: Authors: Dougherty EC;Calhoun HG Title: Possible significance of free-living nematodes in genetic research. Citation: Nature 161: 29-29 1948 Type: ARTICLE Genes: Abstract: The free-living nematodes of the sub-order Rhabditina are widespread in the soil and relatively easily cultivable on nutrient agar in the presence of bacteria and have short life-cycles (3-7 days from hatching to sexual maturity), with adult sizes up to 3 mm in length. They offer, in our estimation, certain very interesting possibilities for the study of basic genetic phenomena-morpholical, cytogenetic and physiological. ------------------- Key: 102 Medline: Authors: Dougherty EC;Hansen EL Title: Axenic cultivation of Caenorhabditis briggsae (Nematoda: Rhabditidae). V. Maturation on synthetic media. Citation: Proc. Society for Experimental Biology & Medicine 93: 223-227 1956 Type: ARTICLE Genes: Abstract: The free-living, soil-dwelling, hermaphroditic rhabditid nematode, C. briggsae, can mature under axenic conditions on a variety of media containing ingredients of complex, undefined composition-for example, certain liver fractions, plasma protein fractions, chick embryo juice, and extracts of equine pancreas, thymus, or spleen. Some of these media have also contained a large number of added known substances, but, until recently, all have included at high levels certain of the complex, crude substances mentioned. However, we have recently recorded success in rearing C. briggsae from larva to larva on a defined medium containing only a trace of the standard liver medium used by us in maintenance of stock axenic cultures of this organism. Now we are able to describe limited success following elimination of even this trace, such that C. briggsae can be reported as passing one generation on certain media of synthetic composition. ------------------- Key: 103 Medline: Authors: Dougherty EC;Hansen EL Title: The folic acid requirement and its antagonism by aminopterin in the nematode C. briggsae (Rhabditidae). Citation: Anatomical Record 128: 541-542 1957 Type: ARTICLE Genes: Abstract: Recently we have reported a high folic acid (FA) requirement for C. briggsae (by comparison with many lower organisms) when grown axenically in a simply prepared liver medium: autoclaved liver extract (ALE). It can now be stated that in this medium AF cannot be replaced by biopterin (one form of the "crithidia factor" - viz., 2-amino-4-hydroxy-6-[1,2,3-trihydroxypropyl-(L-erythro)]-pt eridine) or by pABA... ------------------- Key: 104 Medline: Authors: Dougherty EC;Hansen EL;Nicholas WL;Mollett JA;Yarwood EA Title: Axenic cultivation of Caenorhabditis briggsae (Nematoda: Rhabditidae) with unsupplemented and supplemented chemically defined media. Citation: Annals of the New York Academy of Sciences 77: 176-217 1959 Type: REVIEW Genes: Abstract: A detailed summary of methods for axenic cultivation of Caenorhabditis briggsae is given. Results of axenic culture on chemically defined basal media (GM and GS) and on these media supplemented with undefined preparations of horse liver and chick embryos are reported in detail, with a review of the formulation of the GM and GS designs and of the chronology of changes made therein. The best growth so far realized with C. briggsae in axenic culture is suboptimal as compared with growth in the presence of bacteria, and maturation takes longer (4 to 5 days instead of about 3 days at 20C). Suitable media of the GM design give good axenic growth with relatively low levels of complex supplements-Liver Protein Fraction C (LPF-C) and chick embryo extract (CEE), both of which presumably include a protein-linked requirement, Factor Rb. With GM-16 plus CEE or certain GSs plus CEE, requirements have been variously demonstrated for 6 B-vitamins: folic acid, niacinamide, pantothenic acid, pyridoxine, riboflavin, and thiamine; one of these-folic acid-had already been shown to be required. Only niacinamide is also demonstrated as a requirement in the presence of low levels of LPF-C. In the presence of CEE we have tested the essentiality of the other 5 vitamins only by omitting them singly from vitamin mixes added at increased (5 to 50 times GS) levels to media of GM or GS type. Preliminary evidence is given that the ten "rat-essential" amino acids are required. Improvement of nutritional balance with respect to amino acid levels and to relative levels of amino acids in relation to vitamins or salts is discussed as an explanation of differential growth on different media. Possibly the variations of DM-GS so far tested contain unnecessarily high amino acid levels. The definition of nutritional requirements for C. briggsae still presents many ------------------- Key: 105 Medline: Authors: Dougherty EC;Keith DF Title: The axenic cultivation of Rhabditis briggsae Dougherty & Nigon, 1949 (Nematoda: Rhabditidae) IV. Plasma protein fractions with various supplementations. Citation: Journal of Parasitology 39: 381-384 1953 Type: ARTICLE Genes: Abstract: The immediately preceding paper (Dougherty, 1953) has been confined to an account of work with liver as a source of factor Rb. In the present paper we deal with studies using human plasma as a source of this substance (or substances). A preliminary note briefly reporting a part of the results has already appeared (Dougherty, 1951). Whole plasma and its protein fractions and certain subfractions (See Haurowitz, 1950, pp. 148-160) have been tested. These studies throw additional light on the nature of factor Rb. ------------------- Key: 106 Medline: Authors: Dougherty EC;Nigon V Title: The effect of "acriflavine" (a mixture of 2,8-diaminoacridine and 2,8-diamino-10-methyl-acridinium-chloride) on the growth of the nematode C. elegans. Citation: International Congress of Zoology 14: 247-249 1953 Type: ARTICLE Genes: Abstract: "Acriflavine" (in the form of hydrochlorides of its two components) has a remarkable effect on the growth of C. elegans at 13C. It may be readily incorporated in a wide range of concentrations into the peptone-lecithin-mineral agar customarily used by us in rearing this species. Concentrations of 1:250, 1:500, 1:1000, 1:10,000, and 1:100,000 have been tested. Of these, the 1:1000 concentration has proved the most interesting. When adult hermaphrodites are allowed to lay on agar mounds containing acriflavine at 1:1000, larvae hatch from the eggs and grow, but in no case reach maturity if confined strictly to the agar. Moreover, if left 3 or more days on this medium, they fail in most cases to mature when transferred to normal medium. On the latter some have survived immature for over 35 days after transfer, far longer than the usual life expectancy of the normal worm growing with adequate food and without inhibitory substances present..... ------------------- Key: 107 Medline: Authors: Dougherty EC;Raphael JC;Alton CM Title: The axenic cultivation of Rhabditis briggsae I. Experiments with chick embryo juice and chemically defined media/ Citation: Proc. Helminthological Society of Washington 17: 1-10 1950 Type: ARTICLE Genes: Abstract: ------------------- Key: 108 Medline: Authors: Drechsler C Title: A new species of Stylopage preying on nematodes. Citation: Mycologia 28: 241-246 1936 Type: ARTICLE Genes: Abstract: In Zopf's account of tha capture of nematodes by Arthrobotrys oligospora Fres. and Monosporidium repens Zopf were described, apparently for the first time, instances of a biological habit comparable in part to the carnivorous habit of insectivorous flowering plants. More recently nearly a score of additional fungi occurring in soil, in leaf mold, and in solid decaying materials generally, have been found to capture and consume nematodes in large numbers; evidently, indeed, subsisting in nature entirely through such predacious activity. By far most of these fungi are closely related to those dealt with by Zopf, being referable to a group of interrelated genera including Arthrobotrys, Trichothecium, Cephalothecium, Dactylaria, Dactylella and Monacrosporium. The relatively few nematode-capturing forms alien to this hyphomycetous series are conidial phycomycetes belonging to a Zoopagaceae, a family whose known members are mostly destructive to terricolous amoebae, some operating in parasitic, other predacious relationships. Of the few species preying on nematodes, only one, Stylopage hadra Drechsl., has hitherto been described in detail; so that the description offered herein, of a second species of like biological habit, may be of interest even in the absence of pronounced departures in morphology. ------------------- Key: 109 Medline: Authors: Drechsler C Title: Three fungi destructive to free-living terricolous nematodes. Citation: Journal of the Washington Academy of Sciences 30: 240-254 1940 Type: ARTICLE Genes: Abstract: In several earlier papers comparative treatment was accorded to 24 fungi that had been observed to subsist on free-living nematodes infesting old agar cultures started from diseased rootlets or from other decaying vegetable materials. As the agar media employed were of a concentration sufficient to insure a rather firm consistency together with relative freedom from liquid water, the cultures provided approximately terrestrial rather than aquatic conditions, and therefore not only encouraged the multiplication of eelworms mainly terrestrial with respect to source and adaptation, but also permitted development of the similarly terrestrial fungi habitually destructive to them under natural conditions.... ------------------- Key: 110 Medline: Authors: Drechsler C Title: Three new Hyphomycetes preying on free-living terricolous nematodes. Citation: Mycologia 32: 448-470 1940 Type: ARTICLE Genes: Abstract: In an earlier paper was given a comparative account of 18 interrelated mucedinaceous fungi found to subsist habitually on nematodes that they capture by means of vegetative parts variously adapted for prehension. These fungi had come to light in agar cultures started from discolored rootlets or from other affected vegetable materials, and later often further planted with pinches of friable leaf mold. Similar cultures prepared as circumstances permitted during the last few years have revealed 3 additional mucedinaceous forms obviously belonging in the same series as those previously discussed, and like them observed subsisting by the capture of free-living terricolous eelworms. As the forms appear not to have been recorded hitherto in mycological literature, they are described herein as a species new to science. ------------------- Key: 111 Medline: Authors: Drechsler C Title: Some hyphomycetes parasitic on free-living terricolous nematodes. Citation: Phytopathology 31: 773-802 1941 Type: ARTICLE Genes: Abstract: Agar plate cultures, prepared in the isolation of parasitic oomycetes from discolored roots or other decaying plant materials, often permit abundant multiplication of free-living nematodes, which then are frequently destroyed in large numbers by various predaceous and parasitic fungi. As the parasitic manner of attack, wherein infection comes about from germination of affixed or ingested spores, is shared widely among fungi, it is not surprising that the parasitic forms destructive to eelworms are rather diverse in their taxonomic relationships. Thus, while the 3 parasites that I described earlier under the binomials Euryancale sacciospora, Haptoglossa heterospora, and Meristacrum asterospermum, all belong in the Phycomycetes, they are referable to 3 different groups within that class. Ten additional species, similarly parasitic, but, from their septate vegetative mycelium, obviously belonging with the higher rather than with the lower fungi, are described herein. Important or conspicuous differences in the morphology of their conidial apparatus divide these species into 4 catagories, only one of which is represented by more than a single genus. ------------------- Key: 112 Medline: Authors: Drechsler C Title: Three hyphomycetes that capture nematodes in adhesive networks. Citation: Mycologia 36: 138-171 1944 Type: ARTICLE Genes: Abstract: In several previous papers descriptive treatment was given to 22 interrelated hyphomycetes found subsisting by the capture and destruction of eelworms infesting transparent agar plate cultures started from diseased rootlets or from other decaying vegetable materials. Similar treatment is devoted herein to 3 additional fungi of like biological habit and manifestly belonging to the same predaceous series. Capture of eelworms is accomplished, in all 3 fungi, by means of adhesive bail-like hyphal loops, which, as in allied forms, may occur singly, or may be compounded into networks of variable intricacy. Two of the fungi are referred to Arthrobotrys, one being presented as a new variety, while the other is identified with a long-established though somewhat unfamiliar species of that genus. The third fungus is described as a new species of Dactylaria. In relation to a subsidiary spore form apparently connected with the new species, preliminary discussion is devoted to a delicate Trichothecium found producing stalked adhesive knob-cells. ------------------- Key: 113 Medline: Authors: Drechsler C Title: A species of Harposporium invading its nematode host from the stoma. Citation: Bulletin of the Torrey Botanical Club 73: 557-564 1946 Type: ARTICLE Genes: Abstract: In 1874 Lohde briefly described a hyphomycete that he found growing parasitically on numerous eelworms belonging to a species of Anguillula. To this hyphomycete he applied the binomial Harposporium Anguillulae; the generic term then presented for the first time having reference to the crescentically curved, sickle-shaped conidia which the fungus produced terminally on delicate sterigmata arising singley from peculiar round protuberances formed laterally on the hyphal branches or hyphal prolongations that were extended from the multicellular mycelial filaments, from 2 to 4 in number, passing through the animals body.... ------------------- Key: 114 Medline: Authors: Dropkin VH;Lower WR;Acedo J Title: Growth inhibition of C. elegans and Panagrellus redivivus by selected mammalian and insect hormones. Citation: Journal of Nematology 3: 349-355 1971 Type: ARTICLE Genes: Abstract: Caenorhabditis elegans and Panagrellus redivivus were cultured in axenic medium in microwells. The addition of selected steroids and terpenoids to the medium caused quantitative inhibition of numbers of offspring produced per well. Three out of 14 vertebrate sex hormones and analogs, and seven out of 10 insect juvenile hormones and analogs inhibited growth at 25 or 50 micrograms per ml. In addition, two insecticide synergists which mimic juvenile hormones, propyl 2-propynyl phenyl phosphonate and piperonyl butoxide, inhibited growth at 7 ug/ml. Total lipids from Panagrellus and from Nematospiroides dubius were inhibitory. Separation by silicic acid column chromatography yielded active and inactive portions. We concluded that the inhibition observed was non-specific. ------------------- Key: 115 Medline: 73197027 Authors: Dusenbery DB Title: Countercurrent separation: A new method for studying behavior of small aquatic organisms. Citation: Proceedings of the National Academy of Sciences USA 70: 1349-1352 1973 Type: ARTICLE Genes: Abstract: A new method for the analysis of behavior in small free-swimming aquatic organisms is described. In this procedure, called countercurrent separation, a dense solution flows down along the bottom of an inclined chamber while a light solution flows in the opposite direction, upward along the top of the chamber. The attraction of animals (injected into the center of the chamber) to one solution or the other is then determined by observing the proportion of animals that emerges from the chamber in that solution. When used with the nematode Caenorhabditis elegans, it is estimated that the apparatus is equivalent to at least nine theoretical plates. ------------------- Key: 116 Medline: 74143587 Authors: Dusenbery DB Title: Analysis of chemotaxis in the nematode C. elegans by countercurrent separation. Citation: Journal of Experimental Zoology 188: 41-47 1974 Type: ARTICLE Genes: Abstract: C. elegans responds to several common chemicals. Comparisons of pairs of ions at equivalent concentrations indicated orders of attractiveness of: Na+ > K+ > 1/2 Mg++ > 1/2 Ca++. Cl- > 1/2 SO4-- > NO3- > CH3COO-. The least attractive pair of ions, calcium acetate, is attractive, indicating all these ions are attractive. The most attractive pair, sodium chloride, was attractive from a threshold of 0.1 mM to at least 50 mM. The response to NaCl was maximal throughout the temperature range 15 to 25C and the pH range 3.0 to 9.0. Acid was avoided and base was attractive from concentrations of 0.1 to 1 mM. Dissolved CO2 in the concentration range 0.1 to 1 mM was attractive in 10 mM sodium borate buffer, pH 8.8, but avoided in 25 mM potassium phosphate, pH 6.0. All these responses are likely to affect the distribution of C. elegans in nature and they also provide a tool for promising studies in ------------------- Key: 117 Medline: 76026434 Authors: Dusenbery DB Title: The avoidance of D-Tryptophan by the nematode C. elegans. Citation: Journal of Experimental Zoology 193: 413-418 1975 Type: ARTICLE Genes: Abstract: In chemotactic studies employing countercurrent separation the nematode Caenorhabditis elegans was found to avoid D-tryptophan with a threshold in the range 10(-4) to 10(-3) M. There was no response to L-tryptophan up to 10(-2) M although it appeared to partially inhibit the response to D-tryptophan. ------------------- Key: 118 Medline: 76138995 Authors: Dusenbery DB Title: Attraction of the nematode C. elegans to pyridine. Citation: Comparative Biochemistry & Physiology 53C: 1-2 1976 Type: ARTICLE Genes: Abstract: 1. The nematode C. elegans is attracted to pyridine. 2. The threshold is about 0.1 mM. 3. At concentrations above 1 mM the response weakens. 4. No indication of avoidance of high concentrations could be found. ------------------- Key: 119 Medline: Authors: Dusenbery DB Title: Chemotactic behavior of mutants of the nematode C. elegans that are defective in their attraction to NaCl. Citation: Journal of Experimental Zoology 198: 343-352 1976 Type: ARTICLE Genes: tax-1 tax-2 tax-3 tax-4 tax-5 Abstract: Wild-type C. elegans and 16 derivative strains previously selected for defective attraction to NaCl and shown to carry single-gene mutations were tested for their responses to nine chemical stimuli to which the wild-type responds. These were the attractants Na+, Cl-, OH-, cyclic AMP, CO2 in borate buffer, and pyridine and the repellents D-tryptophan, CO2 in phosphate buffer, and acid. All together 563 measurements were performed. Most strains were defective in most responses but responded normally to some chemical stimuli. In a few cases mutant strains avoided a chemical that attracted the wild-type. Analysis of the patterns of defective responses among these mutants indicates that there are probably at least four different receptors. If results previous reported are included, the minimum number of receptors is increased to six. These mutations appear to have rather discrete effects on ------------------- Key: 120 Medline: Authors: Dusenbery DB Title: Chemotactic responses of male C. elegans. Citation: Journal of Nematology 8: 352-355 1976 Type: ARTICLE Genes: lon-2 Abstract: Cultures of C. elegans containing a high proportion of males were subjected to chemotactic tests by using the method of countercurrent separation. The responses of males and hermaphrodites were determined. Both types of worms preferred Na+ over 1/2 Ca++, Cl- over NO3-: they were attracted to NaCl, OH-, cyclic AMP, pyridine, CO2 in borate buffer (pH 8.8); and avoided CO2 in phosphate buffer (pH 6.0), D-tryptophan, and acid. It was thus concluded that male C. elegans have the same chemotactic responses that hermaphrodites of this species are known to have. ------------------- Key: 121 Medline: Authors: Dusenbery DB;Anderson GL;Anderson EA Title: Thermal acclimation more extensive for behavioral parameters than for oxygen consumption in the nematode C. Citation: Journal of Experimental Zoology 206: 191-198 1978 Type: ARTICLE Genes: Abstract: Thermal acclimation in the free-living soil nematode, Caenorhabditis elegans was studied by determining effects of both growth and test temperatures on oxygen consumption and behavior. Growth temperature (15, 20, or 25C) had no significant influence on oxygen consumption in the range 10-30C, although cold-grown worms had higher consumption at 5C. In contrast, measurements of the fraction of worms moving at any instant and of chemotaxic ability both showed nearly complete thermal acclimation (in the sense that activity-temperature relationships were shifted nearly as much as the differences in growth temperature). Measurements of the rates of acclimation using the behavioral assays indicated acclimation is half complete in about two hours. ------------------- Key: 122 Medline: 75168771 Authors: Dusenbery DB;Sheridan RE;Russell RL Title: Chemotaxis-defective mutants of the nematode C. elegans. Citation: Genetics 80: 297-309 1975 Type: ARTICLE Genes: tax-1 tax-2 tax-3 tax-4 tax-5 Abstract: The technique of countercurrent separation has been used to isolate 17 independent chemotaxis-defective mutants of the nematode Caenorhabditis elegans. The mutants, selected to be relatively insensitive to the normally attractive salt NaCl, show varying degrees of residual sensitivity; some are actually weakly repelled by NaCl. The mutants are due to single gene defects, are autosomal and recessive, and identify at least five complementation groups. ------------------- Key: 123 Medline: 78054765 Authors: Edgar RS;Wood WB Title: The nematode C. elegans a new organism for intensive biological study. Citation: Science 198: 1285-1286 1977 Type: NEWS Genes: Abstract: At a recent conference in Woods Hole, Massachusetts, investigators met to discuss the nematode Caenorhabditis elegans. This free-living worm may, according to some workers, become the Escherichia coli or at least the bacteriophage T4 of the animal world. Small (about 1mm in length) and semitransparent, C. elegans provides for research the advantages of a short life cycle (3 days) and a simple anatomy-it contains about 810 nongonadal nuclei. It is both easy to cultivate, on E. coli as a food source, and convenient for genetic analysis. Its genes are carried on five autosomes and a sex chromosome (X), and it has a genome size about 20 times that of E. coli. It generally reproduces as a self-fertilizing hermaphrodite (XX), but occasional males (XO), which arise by nondisjunction, permit sexual reproduction as well.... ------------------- Key: 124 Medline: 79180186 Authors: Emmons SW;Klass MR;Hirsh D Title: Analysis of the constancy of DNA sequences during development and evolution of the nematode C. elegans. Citation: Proceedings of the National Academy of Sciences USA 76: 1333-1337 1979 Type: ARTICLE Genes: Abstract: In order to test for the occurrence of rearrangements in DNA during development and to assess the rate of DNA divergence during evolution, we have compared restriction fragments derived from DNA from four sources: sperm cells and somatic tissues of one strain of the nematode Caenorhabditis elegans, somatic tissues of a second strain of the same species, and whole animals of a closely related species. Restriction fragments were detected by hybridizing radioactive cloned fragments to restriction digests that had been fractionated by size on agarose gels and transferred to nitrocellulose sheets. In this way, approximately 50 BamHI restriction fragments were visualized and compared. Fragments from sperm and somatic DNAs were found to be identical; 15% differed in size between the two strains. Little cross homology was found between the two species. We conclude that, if rearrangements occur in C. elegans DNA during development, they must affect fewer than a few percent of the restriction fragments or restriction sites. The difference found between the two strains and the two species is ------------------- Key: 125 Medline: Authors: Epstein HF;Schachat FH;Wolff JA Title: Molecular genetics of nematode myosin. Citation: "Pathogenesis of the Human Muscular Dystrophies." Rowland LP (ed), Excerpta Medica, Amsterdam. : 460-467 1976 Type: REVIEW Genes: unc-54 Abstract: The genetics of a small, free-living nematode, Caenorhabditis elegans, has been utilized recently to characterize many mutants affecting the development, function and structure of nerve and muscle. A number of mutants induced by ethyl methane sulfonate (EMS) have been discovered and specifically disrupt the myofibrillar elements of body wall muscle cells, leading to paralysis. One of these mutants, E675, produces an abnormal myosin heavy chain in body wall muscles. Several other mutants as well as E675 are the results of mutation within unc-54, a gene on chromosome I.... ------------------- Key: 126 Medline: Authors: Epstein HF;Harris HE;Schachat FH;Suddleson EA;Wolff JA Title: Genetic and molecular studies of nematode myosin. Citation: CSH Conference on Cell Proliferation 3: 203-214 1976 Type: REVIEW Genes: unc-54 Abstract: The organization of any contractile system requires a series of regulated interactions between genes, structural proteins and movement to occur in a precise manner. The goal of our studies is to understand, at least in outline, some of the principles governing these interactions within the muscle cells of the nematode Caenorhabditis elegans. Our approach has been to analyze the consequences of mutations in the unc-54 gene upon the movement of animals, the arrangement of contractile filaments within body wall muscle cells and the molecular properties of myosin. ------------------- Key: 127 Medline: Authors: Epstein HF;Isachsen MM;Suddleson EA Title: Kinetics of movement of normal and mutant nematodes. Citation: Journal of Comparative Physiology A 110: 317-322 1976 Type: ARTICLE Genes: che-2 dpy-10 unc-4 Abstract: The nematode, Caenorhabditis elegans, is strongly attracted towards secretions of Escherichia coli. The movement of a population of nematodes from the center of an agar plate through a gradient of these secretions towards bacteria at the circumference can be represented by a series of first-order rate processes. Normal and mutant strains of various kinds demonstrate marked differences in their rates of movement. This method of kinetic analysis appears to have a useful potential in the characterization of mutants in nerve and muscle as to whether sensory or locomotive machinery is affected and in the isolation of new mutants of these types. ------------------- Key: 128 Medline: 74284321 Authors: Epstein HF;Thomson JN Title: Temperature sensitive mutation affecting myofilament assembly in C. elegans. Citation: Nature 250: 579-580 1974 Type: ARTICLE Genes: unc-45 Abstract: The assembly of contractile and calcium-related regulatory proteins into functioning myofilament arrays within muscle cells and the genetic control of muscle differentiation are still largely unknown processes. Here we present evidence that a particular gene may regulate such lattice assembly in the body wall muscle cells of the nematode Caenorhabditis elegans. A temperature-sensitive mutation in this gene can prevent the appearance of normal myofilament lattices in this muscle without affecting the amounts of major contractile proteins present. The organised or defective adult structures once formed in mutant muscle are stable to changes in temperature. ------------------- Key: 129 Medline: 75116750 Authors: Epstein HF;Waterston RH;Brenner S Title: A mutant affecting the heavy chain of myosin in C. elegans. Citation: Journal of Molecular Biology 90: 291-300 1974 Type: ARTICLE Genes: unc-54 Abstract: A set of non-complementing, closely-linked, ethyl methanesulphonate-induced mutations in Caenorhabditis elegans specifically affects the structure and function of body-wall muscle cells but not the pharyngeal musculature. One of these mutations, e675, is semidominant and results in the production of a new protein of about 203,000 molecular weight in addition to normal myosin at about 210,000 Mr. The abnormal polypeptide chain is structurally very similar to normal myosin heavy chain when maps of iodinated peptides are compared. The E675 mutant shows a clear relation between defective movement, disruption of the body-wall muscle structure, and the molecular defect in the myosin heavy chains. The altered chain is snythesized in heterozygotes, suggesting that the e675 mutation is either in a structural gene for the heavy chain or in a cis acting control element. The hypothesis that there are two classes of myosin heavy chain within the same cells is ------------------- Key: 130 Medline: Authors: Epstein J;Castillo J;Himmelhoch S;Zuckerman BM Title: Ultrastructural studies on C. briggsae. Citation: Journal of Nematology 3: 69-78 1971 Type: ARTICLE Genes: Abstract: A study of the fine structure of Caenorhabditis briggsae revealed several features not previously described in free-living nematodes. These were: chambered walls of the stoma, zonula adherens in the esophagus, daedaloid folds in the inner surface of the uterus and openings in the terminal web of the intestinal epithelium. Other structures observed in these studies were similar to those described from other free-living nematodes. ------------------- Key: 131 Medline: Authors: Epstein J;Gershon D Title: Studies on ageing in nematodes IV. The effect of antioxidants on cellular damage and life span. Citation: Mechanisms of Ageing & Development 1: 257-264 1972 Type: ARTICLE Genes: Abstract: The effect of the antioxidant a-tocopherolquinone (a-TQ) on the free-living nematode Caenorhabditis briggsae was studied. a-TQ was found to prolong markedly the life span of the animals. The 50% survival of treated animals was extended by 11 days to 46 +/- 2 days as compared with 35 +/- 2 days in control populations. a-TQ also caused a marked delay in the appearance of age-pigment in the intestinal tissue of ageing animals and partially prevented its accumulation. A positive correlation between the delay in age-pigment accumulation and the prolongation of life span was shown. The significance of the effect of antioxidant on the life span and cell damage, and the possible role of peroxidation reactions in senescence, are ------------------- Key: 132 Medline: Authors: Epstein J;Himmelhoch S;Gershon D Title: Studies on ageing in nematodes III. Electronmicroscopical studies on age-associated cellular damage. Citation: Mechanisms of Ageing & Development 1: 245-255 1972 Type: ARTICLE Genes: Abstract: The free-living nematode Caenorhabditis briggsae was used as a model for the study of the phenomenon of ageing. Electronmicroscopical examination of cross-sections through animals of different ages revealed severe damage to certain tissues of aged Caenorhabditis briggsae. Progressive age-dependent accumulation of pigment granules containing acid phosphatase activity was demonstrated in the intestinal epithelium of ageing animals. It is suggested that these granules are age-pigment which is the product of peroxidation of cellular constituents. These pigment granules eventually occupy most of the cytoplasmic volume and appear to lead to the breakdown of the entire tissue. At the terminal period of the animal's life, extensive damage to body muscle tissue and nerve complexes is observed. ------------------- Key: 135 Medline: 67135803 Authors: Fatt HV Title: Nutritional requirements for reproduction of a temperature-sensitive nematode, reared in axenic culture. Citation: Proc. Society for Experimental Biology & Medicine 124: 897-903 1967 Type: ARTICLE Genes: Abstract: 1. Temperature-sensitivity in C. elegans Bergerac is a complex system, composed of a combination of factors, i.e., a) the production of an inhibitory factor in response to higher temperatures, and b) nutritional requirements consisting of proper mineral balance and certain vitamins. 2. Temperature-sensitivity can be overcome by growing the worms at 17C in 50% heated liver extract + 30% partially defined (peptone) medium and heat-treating them at 27C for 27 hours in distilled water or in cold blooded Ringers solution. Worms grown in 50% liver extract + water and heat-shocked in distilled water do not reproduce. Deletion and addition of groups of nutrients to the medium indicates that both vitamins and salts are required for protection against heat-shock in distilled water. 3. The need for extra vitamins is eliminated when the worms are grown at 17C in 50% liver extract + water and heat-shocked in Ringers solution. Comparison of the salts in the peptone medium and Ringers solution suggests that either Na+ or (less likely) HCO3- could be responsible for protection against higher temperatures. ------------------- Key: 137 Medline: Authors: Fatt HV;Dougherty EC Title: Genetic control of differential heat tolerance in two strains of the nematode Caenorhabditis elegans. Citation: Science 141: 266-267 1963 Type: ARTICLE Genes: Abstract: Two strains (Bergerac and Bristol) of the nematode Caenorhabditis elegans, with different temperature tolerances, were reared axenically at 23C to 25C. The Bergerac strain is heat sensitive (that is, it is sterile at maturity), whereas the Bristol strain is heat resistant (that is, it matures and reproduces normally). Hybrid hermaphrodites (F1), produced by crossing Bristol males and Bergerac hermaphrodites, are heat tolerant. Heat sensitivity segregates as a simple Mendelian recessive in the F2 and F3 generations. ------------------- Key: 138 Medline: Authors: Fiakpui EZ Title: Some effects of piperazine and methyridine on the free-living nematode C. briggsae (Rhabditidae). Citation: Nematologica 13: 241-255 1967 Type: ARTICLE Genes: Abstract: Some biological effects of methyridine and piperazine on Caenorhabditis briggsae have been investigated using in vitro techniques on intact worms. It has been found that methyridine produces a contracted paralysis which is not reversed in drug-free medium and piperazine produces a flaccid paralysis reversible in drug-free medium. Methyridine and piperazine negate the action of each other competitively. Different types of evidence have been presented and discussed to show that drugs affect the neuromuscular system of C. briggsae, methyridine being a depolarizing agent and piperazine a neuro-muscular junction blocking agent. ------------------- Key: 140 Medline: Authors: Friedman PA;Platzer EG;Eby JE Title: Species differentiation in C. briggsae and C. elegans. Citation: Journal of Nematology 9: 197-203 1977 Type: ARTICLE Genes: Abstract: Identification of five laboratory strains (1-5) of putative Caenorhabditis briggsae was undertaken. Examination of the male bursal ray arrangement, mating tests with males of Caenorhabditis elegans, malate dehydrogenase zymograms, and SDS polyacrylamide electrophoresis demonstrated that strain 4 was C. briggsae and the others were C. elegans. ------------------- Key: 141 Medline: Authors: Fuchs AC Title: Neue parasitische und halbparasitische Nematoden bei Borkenkafern und einige andere Nematoden I. Teil. Citation: Zoologische Jahrbucher - Abt. Zool. Phys. der Tiere 70: 291-380 1937 Type: ARTICLE Genes: Abstract: ------------------- Key: 142 Medline: Authors: Galsky AG;Monoson HL;Williams SA Title: A bioassay for measuring crude nematode extract which induced trap formation in a predaceous fungus. Citation: Nematologica 20: 39-42 1974 Type: ARTICLE Genes: Abstract: A bioassay for quantitatively measuring the ability of a nematode to induce trap formation in a predaceous fungus is described. The bioassay was sensitive to changes in the crude nemin concentration and is specific for the crude nemin. In addition, the bioassay can be performed rapidly and inexpensively. The bioassay provides an important tool that can be used in measuring nematode-predaceous fungus interrelationships. ------------------- Key: 143 Medline: 79063845 Authors: Garcea RL;Schachat F;Epstein HF Title: Coordinate synthesis of two myosins in wild-type and mutant nematode muscle during larval development. Citation: Cell 15: 421-428 1978 Type: ARTICLE Genes: unc-54 Abstract: In this paper we examine the role of two myosins in body-wall muscle cells of the nematode Caenorhabditis elegans. Large populations of nematodes are synchronized, and the synthesis and accumulation of myosin heavy chains and total protein are followed through postmitotic larval development. Growth is exponential with time for both the wild-type N2 and the body-wall muscle-defective mutant E675, with a longer doubling time for the mutant. Utilizing the electrophoretic polymorphism of the E675 myosin heavy chains, we show that distinguishable classes of heavy chains accumulate differentially throughout development. Immunochemical measurements confirm a similar result in N2. Total myosin heavy chain accumulation is also quantitatively similar for the two chains. Myosin heavy chain relative synthetic rates as determined by pulse-labeling are constant throughout development and are equivalent for the two strains. The final fraction of accumulated unc-54 to total heavy chains of approximately 0.63 equals the constant synthetic fraction of approximately 0.62. Since myosin heavy chain accumulation and relative synthesis are equivalent, we conclude that the turnover of heavy chains is also similar in N2 and E675 despite the extensive structural and functional disruption within body-wall muscle cells of the latter strain. Since the accumulated fraction of unc-54 myosin heavy chains reaches a plateau at the constant synthetic fraction, myosin accumulation in the body-wall muscle cells may be attributed to a constant ratio of synthetic rates of the two body-wall myosin species. The coordinate synthesis of two myosins in the same body-wall muscle cells is ------------------- Key: 146 Medline: 70042404 Authors: Ghiselin M Title: The evolution of hermaphroditism among animals. Citation: Quarterly Review of Biology 44: 189-208 1969 Type: REVIEW Genes: Abstract: Possible selective advantages, including some new ones, for hermaphroditism are reviewed. It is proposed that hermaphroditism should evolve under the following conditions: (a) where it is hard to find a mate; (b) where one sex benefits from being larger or smaller than the other; or (c) where there are small, genetically isolated populations. Some conceptual problems and a comparative means of study are discussed. The literature is reviewed to show the conditions under which hermaphroditism may have evolved. It is concluded that all three explanations have some validity. ------------------- Key: 147 Medline: Authors: Golovin E Title: Nabliudeniia nad nematodami (Okonchanie). Citation: Uchenye Zapiski Kazan. 68: 1-50 1901 Type: ARTICLE Genes: Abstract: ------------------- Key: 148 Medline: Authors: Gochnauer MB;McCoy E Title: Responses of a soil nematode. Rhabditis briggsae to antibiotics. Citation: Journal of Experimental Zoology 125: 377-406 1954 Type: ARTICLE Genes: Abstract: The two main phases of research on antibiotics have been their modes of action on bacteria and their toxicity measurements which are necessary to determine toxic properties of the drug and to assay extraneous toxic contaminants contained in the commercial product. If at least a part of the preliminary toxicity screening could be made with an organism that is inexpensive to obtain and easy to culture in the laboratory, yet as sensitive and reliable as the mouse as a test animal, production costs could be reduced considerably. Because Rhabditis briggsae, a free-living soil nematode, can be maintained in the laboratory as inexpensively as bacterial culture, it was chosen as a possible test organism for toxicity studies. To obtain a comprehensive value for toxicity, antibiotics known to have different toxicity levels for higher animals were chosen for this investigation. Listed in order of increasing toxicity they are penicillin, streptomycin, and streptolin. ------------------- Key: 149 Medline: 71116308 Authors: Guerrero J;Silverman PH Title: Ascaris suum: Immune reactions in mice II. Metabolic and somatic antigens from in vitro cultured larvae. Citation: Experimental Parasitology 29: 110-115 1971 Type: ARTICLE Genes: Abstract: The immunologic activity of somatic and metabolic antigens derived solely from in vitro cultured second- and early third-stage Ascaris suum larvae was studied in mice. Eagle's Minimum Essential Medium and Caenorhabditis briggsae medium 75 were used. The results demonstrate for the first time that metabolic and somatic antigens harvested after 12 days from in vitro cultures were capable of inducing resistance to reinfection. The effect on immunity to A. suum in mice of somatic and metabolic antigens from: (1) second- and third-stage in vitro cultured A. suum larvae; (2) metabolic and somatic antigens from third- and fourth-stage A. suum; (3) C. briggsae metabolic antigens; and (4) desalted Haemonchus contortus third-stage larvae exsheathing fluid are described. ------------------- Key: 151 Medline: 76065244 Authors: Haight M;Frim J;Pasternak J;Frey H Title: Freeze-thaw survival of the free-living nematode C. briggsae. Citation: Cryobiology 12: 497-505 1975 Type: ARTICLE Genes: Abstract: For a long time nematodes have been noted for their ability to survive drastic environmental challenges such as severe dessication and low temperatures. The properties that enable a fully differentiated, postembyronic multicellular organism to recover from such treatment are of interest. In addition to the intrinsic need to examine the cryobiological behavior of such a hardy organism, the value of the nematode in other research areas has been described. Therefore, a reliable and successful method for long-term preservation would be an advantage for maintaining diverse stock cultures.... ------------------- Key: 152 Medline: Authors: Hansen EL;Berntzen AK Title: Development of C. briggsae and Hymenolepsis nana in interchanged media. Citation: Journal of Parasitology 55: 1012-1017 1969 Type: ARTICLE Genes: Abstract: Chemically defined media supplemented with proteinaceous growth factos have been developed for axenic culture of Caenorhabditis briggsae and Hymenolepis nana. The chemical compositions of the media and characteristics of the growth factors are compared. Either growth factor was found to be an effective supplement for each organism. The chemically defined portions of the media can be interchanged if suitable adjustments are made in the salts and buffers. It therefore appears possible to develop a single basal medium for both types of organism, and to use the convenience of the C. briggsae bioassay for further isolation and the characterization of growth factors for helminths. ------------------- Key: 153 Medline: Authors: Hansen EL;Buecher EJ Title: Biochemical approach to systematic studies with axenic nematodes. Citation: Journal of Nematology 2: 1-6 1970 Type: ARTICLE Genes: Abstract: The application of biochemical systematics to nematology can provide a much needed tool to resolve problems of taxonomy and phylogeny. These problems are most apparent when the morphological characteristics merge between species, when characteristics occur in the rare form, e.g. male in a hermaphroditic species, or when strains show no morphological differences. Biochemical systematics depends on elucidation of the subtle molecular differences which underlie taxonomic variation. The challenge for the nematologist is to recognize the biochemical processes that can yield information for this differentiation and then to prepare sufficient material for investigation..... ------------------- Key: 154 Medline: 72098726 Authors: Hansen EL;Buecher EJ Title: Effect of insect hormones on nematodes in axenic culture. Citation: Experientia 27: 859-860 1971 Type: ARTICLE Genes: Abstract: Insect juvenile hormones (JH) or JH mimetics have been shown to affect development of nematodes: Trichinella spiralis larvae and fourth stage Phocanema decipiens were inhibited, and abnormal morphology was seen in Heterodera schactii. The effects of insect hormones and analogues on development of several free-living and parasitic nematodes cultured axenically are described in the present paper. ------------------- Key: 155 Medline: Authors: Hansen EL;Buecher EJ;Yarwood EA Title: Development and maturation of C. briggsae in response to growth factor. Citation: Nematologica 10: 623-630 1964 Type: ARTICLE Genes: Abstract: Cultural characteristics of Caenorhabditis briggsae were examined in a medium composed of a chemically defined basal medium and a supplement consisting of a proteinous growth factor. In each of the separate components used as a medium, larvae developed through only one molt. Development was resumed when the medium was restored to completeness. In the complex medium maturation was slower and reproduction somewhat reduced compared with that in monoxenic cultures with E. coli. ------------------- Key: 156 Medline: Authors: Hansen EL;Cryan WS Title: Continuous axenic culture of free-living nematodes. Citation: Nematologica 12: 138-142 1966 Type: ARTICLE Genes: Abstract: A new method for continuous thin film axenic culture of nematodes involving a minimum of handling permits attainment of larger populations and higher proportions of adults than is attained in test tube cultures with identical media. The increase in population may be attributable to improved physiological conditions which enhance gas exchange. These observations suggest that results obtained in test tube cultures have led to an underestimation of the nutritional adequacy of the medium. ------------------- Key: 157 Medline: 72095201 Authors: Hansen EL;Perez-Mendez G;Buecher EJ Title: Glycogen as a supplement in media for axenic cultivation of nematodes. Citation: Proc. Society for Experimental Biology & Medicine 137: 1352-1354 1971 Type: ARTICLE Genes: Abstract: Free-living nematodes have been cultured continuously under axenic conditions for several years. The culture medium consists of a chemically defined portion and an organic supplement. All supplements reported thus far, such as liver growth factor and serum y-globulin are proteinaceous and heat-labile. We now report the use of a polysaccharide, glycogen, as an effective heat-stable ------------------- Key: 158 Medline: 77134682 Authors: Harris H;Tso M-Y W;Epstein HF Title: Actin and myosin-linked calcium regulation in C. elegans. Biochemical and structural properties of native filaments and purified proteins. Citation: Biochemistry 16: 859-865 1977 Type: ARTICLE Genes: Abstract: Calcium regulation of actomyosin activity in the nematode, Caenorhabditis elegans, has been studied with purified proteins and crude thin filaments. Actin and tropomyosin have been purified from C. elegans and shown to be similar in most respects to actin and tropomyosin from rabbit skeletal muscle. The actin comigrates with rabbit actin on polyacrylamide-sodium dodecyl sulfate gel electrophoresis, forms similar filaments and paracrystals, and activates the Mg2+-ATPase of rabbit myosin heads as efficiently as rabbit actin. Nematode tropomyosin has a greater apparent molecular weight (estimated by mobility on polyacrilamide-sodium dodecyl sulfate gels) than the rabbit protein, yet it forms Mg2+-paracrystals with a slightly shorter periodicity. Native thin filaments extracted from nematodes activate rabbit myosin subfragment 1 Mg2+-ATPase in a calcium sensitive manner; the extent of activation is threefold greater in 0.2 mM CaCl2 than in the absence of calcium. This observation suggests that the thin filaments contain components which are functionally equivalent to vertebrate troponins. Calcium is also required for maximal activation of the Mg2+-ATPase of purified nematode myosin and thin filament-linked calcium regulatory systems. The origin of the actin, tropomyosin, and myosin from different tissues and the use of genetic analysis to answer questions about assembly and function in vivo are discussed. ------------------- Key: 159 Medline: 77183614 Authors: Harris HE;Epstein HF Title: Myosin and paramyosin of C. elegans: Biochemical and structural properties of wild-type and mutant proteins. Citation: Cell 10: 709-719 1977 Type: ARTICLE Genes: unc-54 Abstract: Myosin and paramyosin have been purified from the nematode, Caenorhabditis elegans. The properties of the myosin in general resemble those of other myosins. The native molecule is a dimer of heavy (210,000 dalton) polypeptide chains and contains 18,000 and 16,000 dalton light chains. When rapidly precipitated from solution, it forms small, bipolar aggregates, about 150 nm long, consistent with the expected molecular structure of a rigid rod with a globular head region at one end. Its ATPase activity is stimulated by Ca2+ and EDTA. The myosin binds to F actin in a polar and ATP-sensitive manner, and the Mg2+-ATPase is activated by either F actin or nematode thin filaments. Dialysis of myosin to low ionic strength produces very long filaments. When a myosin-paramyosin mixture is dialyzed under the same conditions, co-filaments form which consist of a myosin cortex, surrounding a paramyosin core. Some properties of myosins from the mutants E675 and E190, which have functionally and structurally altered body wall muscles, are compared with those of wild-type myosin. These myosins behave normally in in vitro tests. The implications of these results are discussed in terms of the myosin heavy chain composition. ------------------- Key: 160 Medline: Authors: Hedgecock EM Title: The mating system of C. elegans: Evolutionary equilibrium between self- and cross-fertilization in a facultative hermaphrodite. Citation: American Naturalist 110: 1007-1012 1976 Type: ARTICLE Genes: Abstract: Many hermaphroditic species, including the small soil nematode Caenorhabditis elegans, have an evolutionary option not available to strictly dioecious species or to organisms committed exclusively to monoparental reproduction. The ratio of self-fertilization to cross-fertilization can be adjusted in a nearly continuous fashion to obtain the maximum reproductive potential in a constant or changing environment. In C. elegans, this involves modulating the frequency of male production and the efficiency of their mating. Since a single hermaphrodite produces nearly 300 fertile eggs, whether by selfing or by mating, the advantage of sexual reproduction must be balanced against the dilution of the maternal genetic material which accompanies mating. This paper derives the frequency of male production and the efficiency of mating in C. elegans from a simple deterministic model of a population with discrete generations at approximate equilibrium. Both parameters are experimentally ------------------- Key: 161 Medline: 76078399 Authors: Hedgecock EM;Russell RL Title: Normal and mutant thermotaxis in the nematode C. elegans. Citation: Proceedings of the National Academy of Sciences USA 72: 4061-4065 1975 Type: ARTICLE Genes: tax-1 tax-2 tax-3 tax-4 tax-5 Abstract: When grown at a temperature from 16C to 25C and placed on a thermal gradient, the nematode Caenorhabditis elegans migrates to its growth temperature and then moves isothermally. Behavioral adaptation to a new temperature takes several hours. Starved animals, in contrast, disperse from the growth temperature. Several mutants selected for chemotaxis defects have thermotaxis defects as well; these behaviors depend on some common gene products. New mutants selected directly for thermotaxis defects have unusual phenotypes which suggest mechanims for thermotaxis. ------------------- Key: 162 Medline: 76188534 Authors: Herman RK;Albertson DG;Brenner S Title: Chromosome rearrangements in C. elegans. Citation: Genetics 83: 91-105 1976 Type: ARTICLE Genes: dpy-6 him-1 unc-1 unc-7 mnDp1 mnDp2 mnDp3 mnDp4 mnDp5 Abstract: A method for selecting unlinked duplications of a part of the X chromosome of C. elegans is described. Five such duplications have been identified. One of them, Dp(X;V)1, is translocated to linkage group V, where it suppresses crossing over along the left half of linkage group V. Dp(X;V)1 homozygotes grow slowly and are sterile. The other four duplications are associated with chromosome fragments, as observed cytologically by fluorescence microscopy, and tend to be lost. Their frequency of loss is higher in strains homozygous for a mutation that promotes nondisjunction of X chromosomes. The recombination frequencies between two of these duplications and the X have been measured: the frequencies are at least 50 times less than for X-X recombination in the same region. The duplications may prove useful as balancers of recessive lethal mutations. ------------------- Key: 163 Medline: 78128036 Authors: Herman RK Title: Crossover suppressors and balanced recessive lethals in C. elegans. Citation: Genetics 88: 49-65 1978 Type: ARTICLE Genes: dpy-10 let-19 let-22 let-23 let-24 let-25 let-26 let-27 let-28 let-30 let-31 let-32 unc-4 unc-6 unc-13 unc-24 unc-32 unc-42 mnC1 mnDf71 Abstract: Two dominant suppressors of crossing over have been identified following X-ray treatment of the small nematode C. elegans. They suppress crossing over in linkage group II (LG II) about 100-fold and 50-fold and are both tightly linked to LG II markers. One, called C1, segregates independently of all other linkage groups and is homozygous fertile. The other is a translocation involving LG II and X. The translocation also suppresses crossing over along the right half of X and is homozygous lethal. C1 has been used as a balancer of LG II recessive lethal and sterile mutations induced by EMS. The frequencies of occurrence of lethals and steriles were approximately equal. Fourteen mutations were assigned to complementation groups and mapped. They tended to map in the same region where LG II visibles are clustered. ------------------- Key: 164 Medline: 80025646 Authors: Herman RK;Madl JE;Kari CK Title: Duplications in C. elegans. Citation: Genetics 92: 419-435 1979 Type: ARTICLE Genes: dpy-6 dpy-7 dpy-10 dpy-13 unc-2 unc-6 unc-18 unc-78 mnC1 mnDp1 mnDp2 mnDp8 mnDp9 mnDp10 mnDp25 mnDp26 mnDp27 mnDp30 mnDp31 mnDp32 mnDp33 mnDp34 mnDp35 mnDp36 Abstract: Thirteen chromosomal duplications, all unlinked to their linkage group of origin, have been identified following X-irradiation. Ten are X-chromosome duplications, of which six are half-translocations on three autosomal linkage groups and four are free fragments. Five of the half-translocations are homozygous fertile and two are recognizable cytologically as chromosome satellites, both of which show some mitotic instability. The free-X duplications show varying tendencies for loss. Three appear not to overlap in extent previously identified for free-X duplications. The fourth carries genes from linkage group V, as well as X. Three duplications of a portion of linkage group II were identified and found to be free and quite stable in hyperploids. Some of the free duplications tend to disjoin from the X chromosome in males. New X-chromosome map data are presented. ------------------- Key: 165 Medline: 68199211 Authors: Hieb WF;Rothstein M Title: Sterol requirement for reproduction of a free-living nematode. Citation: Science 160: 778-780 1968 Type: ARTICLE Genes: dpy-7 Abstract: The free-living, hermaphroditic nematode Caenorhabditis briggsae has a nutritional requirement for sterols. It will reproduce indefinitely in a liquid medium containing only bacterial cells (Escherichia coli) and salts if various sterols are present. Several other lipid-soluble materials are ineffective in supporting reproduction. ------------------- Key: 166 Medline: Authors: Hieb WF;Rothstein M Title: Isolation from liver of a heat-stable requirement for reproduction of a free-living nematode. Citation: Archives of Biochemistry & Biophysics 136: 576-578 1970 Type: ARTICLE Genes: Abstract: Free-living nematodes grown in axenic culture require, in addition to a chemically defined medium, a heat-labile "growth factor" which is present in various tissues and bacteria. A purified form of the factor derived from liver extract was reported by Sayre et al to be a discrete protein of high molecular weight which exists in multiple active forms of similar amino acid composition. ------------------- Key: 167 Medline: 70129908 Authors: Hieb WF;Stokstad ELR;Rothstein M Title: Heme requirement for reproduction of a free-living Citation: Science 168: 143-144 1970 Type: ARTICLE Genes: Abstract: The free-living hermaphroditic nematode Caenorhabditis briggsae has a nutritional requirement for heme. The organism can be subcultured repeatedly in a chemically defined axenic medium that contains autoclaved bacterial cells (Escherichia coli) and sterols if a hemeprotein-containing fraction from liver is present. Pure myoglobin, hemoglobin, cytochrome c and hemin, respectively, can substitute effectively for the liver ------------------- Key: 168 Medline: 77099952 Authors: Higgins BJ;Hirsh D Title: Roller mutants of the nematode C. elegans. Citation: Molecular & General Genetics 150: 63-72 1977 Type: ARTICLE Genes: bli-2 dpy-1 dpy-2 dpy-5 dpy-9 dpy-10 dpy-11 dpy-13 lon-2 rol-1 rol-3 Abstract: The wild type nematode, Caenorhabditis elegans, moves in a sinusoidal wave pattern and leaves sinusoidal paths behind it on a bacterial lawn. The nematode crawls on its side on a special cuticular tread that extends straight down the length of its body. Wild type worms also have rows of musculature and a ventral nerve cord that extend straight down the body. Roller mutants rotate around their long axis as they crawl and move in circular paths. Three roller mutants have been studied. Two mutants are left rollers and one is a right roller. The left rollers have left-handed helical treads, body musculatures, and ventral nerve cords whereas these structures are right-handed in the right roller. Double mutants constructed from roller mutants and long mutants indicate that long rollers have helices of the same pitch as normal length rollers. Double mutants constructed from rollers and dumpy mutants that are short and fat indicate dumpy phenotype is epistatic to roller. Double mutants constructed from rollers and blister mutants that have cuticular swelling indicate roller phenotype is epistatic to blister. The results suggest that the roller phenotypes are due to cuticular lesions. Rollers can chemotaxe up a gradient of an attractant by turning off their body muscle movement and continuing their head movements. ------------------- Key: 169 Medline: 78238979 Authors: Himmelhoch S;Zuckerman BM Title: C. briggsae: Aging and the structural turnover of the outer cuticle surface and the intestine. Citation: Experimental Parasitology 45: 208-214 1978 Type: ARTICLE Genes: Abstract: The exposed surface of Caenorhabditis briggsae was examined for the presence of neuraminic acid, hyaluronic acid, and glucuronic acid. None of these molecules was detected. In young nematodes the presence of a surface coat was demonstrated. This surface coat appeared to shrink with age. Ruthenium red staining suggested the presence of acid mucopoly-saccarides on the outer surface. Feeding the nematodes on cationized ferritin enabled visualization of a matrix surrounding the intestinal brush border. Experiments with an inhibitor of acid mucopolysaccharide synthesis suggested that there is no turnover of acid mucopolysaccharides after the final molt of C. briggsae. ------------------- Key: 170 Medline: 77116054 Authors: Himmelhoch S;Kisiel MJ;Zuckerman BM Title: C. briggsae: Electron microscope analysis of changes in negative surface charge density of the outer cuticular membrane. Citation: Experimental Parasitology 41: 118-123 1977 Type: ARTICLE Genes: Abstract: The negative surface charge density of the outer cuticular membrane of Caenorhabditis briggsae was visualized by use of cationized ferritin. When grown axenically in a medium which contained liver extract, the net negative surface charge density was significantly less in nematodes 21-24 days old than in nematodes 6-7 days old. Nematodes grown in heat-treated medium, in which liver enzyme activities were presumably inactivated, did not show lower surface charge densities at 21 days. These findings indicate that the decrease in net negative surface charge was caused by a receptor-destroying enzyme present in the liver extract. The relation of the membrane charge changes observed in vitro to those which might occur in nature is discussed. Further studies showed that the negative charges are evenly distributed over the surface of the nematode except in the tail area, where they are lower. ------------------- Key: 172 Medline: Authors: Hirsh D Title: Patterns of gene expression during development of the nematode C. eleganss. Citation: "Microbiology-1975." Schlessinger D (ed), American Society for Microbiology, Washington DC. : 508-514 1975 Type: REVIEW Genes: Abstract: Much of the discussion in this symposium has addressed the question of how a single cell differentiates into two different daughter cells. Considerable effort is being made to understand the ability of cells to regulate protein synthesis either by temporal regulation at the level of the genome or through the inherent order of assembly of macromolecules, as is seen in the case of T4 bacteriophage late functions. We now turn to consideration of the genetic control of development in an organism which is complex relative to those prokaryotes and unicellular eukaryotes which have been discussed so far. Studies on the development of prokaryotes or simple eukaryotes rely upon the extensive knowledge of how genes are replicated, transcribed, and translated as deciphered over the past 15 years of molecular biology. An alternative approach is required in studying an organism with several cell types and asymmetries in which there is complex development. I have chosen the small nematode Caenorhabditis elegans for studying genetic control of development because it lends itself to detailed morphological studies and because its genetics is now well defined through the elegant work of Brenner...... ------------------- Key: 174 Medline: 76140556 Authors: Hirsh D;Oppenheim D;Klass M Title: Development of the reproductive system of C. elegans. Citation: Developmental Biology 49: 200-219 1976 Type: ARTICLE Genes: Abstract: A morphological study of the growth and the development of the reproductive system of the nematode Caenorhabditis elegans has been carried out. When the first stage larva hatches from the egg it contains four primordial gonadial cells. These cells proliferate and form the entire adult reproductive system, consisting of approximately 2500 nuclei, in 45 h at 25C. Several distinctive morphological features of gonadogenesis and early embryogenesis that are recognizable in the compound microscope can be used to chart the development of the nematode. The mature gonad presents a linear developmental axis both temporally and morphologically of the formation of oocytes, fertilization, and the early stages of embryogenesis. The structure of the adult ovary indicates that the cytoplasm of each newly formed oocyte is derived from a common core of cytoplasm within the multinuclear ovary. ------------------- Key: 175 Medline: 76140557 Authors: Hirsh D;Vanderslice R Title: Temperature-sensitive developmental mutants of C. elegans. Citation: Developmental Biology 49: 220-235 1976 Type: ARTICLE Genes: Abstract: About 200 temperature-sensitive mutants of the nematode Caenorhabditis elegans have been isolated. At restrictive temperature, the mutants are blocked in the reproductive life cycle. They have been placed into six broad categories based on their defective phenotypes. The six categories are: (1) mutants blocked in embryogenesis; (2) mutants defective in gonadogenesis; (3) mutants defective in spermatogenesis; (4) mutants that accumulate at an intermediate growth stage; (5) mutants that produce sterile adult progeny; (6) mutants that have a temperature-sensitive morphological defect that interrupts the reproductive life cycle. The critical times of temperature sensitivity have been measured using temperature-shift experiments. Most of the gonadogenesis and spermatogenesis mutants are temperature sensitive during the period of cellular differentiation rather than proliferation. The temperature responses of the gonadogenesis and zygote-defective mutants indicate a common association between functions in gonadogenesis and early embryogenesis. Many of the mutants placed in different categories share other temperature-sensitive phenotypes upon close examination. This implies that many of the functions required for development are general metabolic reactions under increased demand during ------------------- Key: 176 Medline: 78131001 Authors: Hirsh D;Wood WB;Hecht R;Carr S;Vanderslice R Title: Expression of genes essential for early development in the nematode, C. elegans. Citation: "Molecular Approaches to Eucaryotic Genetic Systems" ICN-UCLA Symposia on Molecular & Cellular Biology, Volume 8. Wilcox G, Abelson J and Fox CF (eds), Academic Press, NY. 8: 347-356 1977 Type: REVIEW Genes: Abstract: Genetic tests for maternal effects have been performed on 25 temperature-sensitive zygote-defective mutants of the nematode Caenorhabditis elegans. For most of the genes defined by these mutants (22 out of 25), maternal expression is sufficient for zygote survival, even if the gene is not expressed in the zygote. Twelve of these 22 genes must be expressed in the mother for zygote survival (strict maternals). For the remaining ten, expression either in the mother or in the zygote is sufficient for survival. One mutant shows a paternal effect in which wild-type sperm cytoplasm appears to rescue mutant zygotes. Maternal effect tests on mutants that block as late as the second larval stage after hatching indicate that in 3 of 11 mutants maternal contributions still can rescue mutant progeny. Temperature shift experiments on the zygote-defective embryos show that all but one of the strict maternal mutants are temperature sensitive only before gastrulation. One of the mutants that can be rescued by gene expression in the zygote is temperature sensitive prior to gastrulation, suggesting that some zygote genes can function in early embryogenesis. ------------------- Key: 177 Medline: Authors: Hitcho PJ;Thorson RE Title: Behavior of free-living and plant-parasitic nematodes in a thermal gradient. Citation: Journal of Parasitology 58: 599-599 1972 Type: ARTICLE Genes: Abstract: Positive thermotactic behavior has been demonstrated in certain parasitic helminths. Unlike most organsims, these parasites did not seek a temperature preferendum, but rather migrated in the gradient until thermal damage and death occurred... ------------------- Key: 178 Medline: 77226072 Authors: Hodgkin JA;Brenner S Title: Mutations causing transformation of sexual phenotype in the nematode C. elegans. Citation: Genetics 86: 275-287 1977 Type: ARTICLE Genes: dpy-21 dpy-22 him-1 lin-4 tra-1 tra-2 tra-3 Abstract: Ten mutations are described that transform genotypic hermaphrodites of the nematode Caenorhabditis elegans into phenotypic males. These fall into three autosomal complementation groups, termed tra-1, tra-2, and tra-3. Two alleles of tra-1 produce almost complete transformation, to a fertile male phenotype; such transformed animals are useful for analyzing sex-linked genes. All alleles of tra-1 and tra-2 are recessive; the one known allele of tra-3 is both recessive and maternal in effect. Where tested, both XX and XXX hermaphrodites are transformed into males, but XO males (true males) are unaffected by these mutations. It is suggested that these genes are actually involved in hermaphrodite development and have no role in male development. ------------------- Key: 179 Medline: Authors: Hodgkin J;Horvitz HR;Brenner S Title: Nondisjunction mutants of the nematode C. elegans. Citation: Genetics 91: 67-94 1979 Type: ARTICLE Genes: dpy-21 him-1 him-2 him-3 him-4 him-5 him-6 him-7 him-8 him-9 unc-86 Abstract: The frequency of males (5AA;XO) among the self progeny of wild-type Caenorhabditis elegans hermaphrodites (5AA;XX) is about one in 500. Fifteen him (for "high incidence of males") mutations have been identified that increase this frequency by a factor of ten to 150, as a result of increased X-chromosome non-disjunction. The mutations define ten complementation groups, which have been mapped: nine are autosomal, and one sex linked. Most of the him mutants are superficially wild type in anatomy and behavior; however, him-4 mutants display gonadal abnormalities, and unc-86 mutants, which have a Him phenotype, exhibit a variety of anatomical and behavioral abnormalities. All the mutants segregate fertile 3X hermaphrodite progeny as well as XO male progeny. Some produce large numbers of inviable zygotes. Mutants in all ten genes produce diplo-X and nullo-X exceptional ova, and in the four strains tested, diplo-X and nullo-X exceptional sperm are produced by 2X "transformed" males. It appears likely that most of the mutants have defects in both gamete lines of the hermaphrodite. XO males of him strains other than him-4 and unc-86 are similar to wild-type males in anatomy and behavior, and all produce equal or almost equal numbers of haplo-X and nullo-X sperm, and no diplo-X sperm. Male fertility is reduced to varying extents in all him mutants. In four of the strains, nondisjunction during oogenesis has been shown to occur at a reductional division, and in three of these strains, abnormalities in recombination have been demonstrated. One mutant also exhibits autosomal nondisjunction, but many of the others probably do not. Therefore, the X chromosome of C. elegans may differ from the autosomes in the machanisms controlling its meiotic behavior. 3X hermaphrodites are shorter and less fertile than 2X hermaphrodites, and they produce many inviable zygotes among their self progeny; these are probably 4X zygotes. Haplo-X and diplo-X ova are produced in 2:1 ratio by 3X hermaphrodites. him mutations are expressed in these animals, increasing the frequency of self-progeny males and 2X hermaphrodites. ------------------- Key: 180 Medline: 75181614 Authors: Johnson CD;Russell RL Title: A rapid, simple radiometric assay for cholinesterase, suitable for multiple determinations. Citation: Analytical Biochemistry 64: 229-238 1975 Type: ARTICLE Genes: Abstract: A rapid and simple radiometric assay for cholinesterase, suitable for multiple determinations, has been developed. (3H-acetyl) choline is enzymatically hydrolyzed in a small reaction volume in a scintillation vial. The released 3H-acetate is then extracted into a toluene-based scintillator added directly to the vial, without removing the reaction volume. The extracted 3H-acetate counts efficiently but the unhydrolyzed 3H-acetylcholine remains unextracted in the small aqueous reaction volume, from which its weak B-particles of decay do not escape to excite the scintillator. The assay is highly reproducible, quite sensitive, and useful for applications in which multiple samples must be quickly assayed. ------------------- Key: 181 Medline: Authors: Hogger CH;Estey RH Title: Cryofracturing for scanning electron microscope observations of internal structures of nematodes. Citation: Journal of Nematology 9: 334-337 1977 Type: ARTICLE Genes: Abstract: Nematodes were prepared for scanning electron microscopy by cryofracturing in ethanol and then by critical-point drying in carbon dioxide. Cross sections of Caenorhabditis briggsae and Xiphinema americanum showed the arrangement of the intestine, ovaries, muscle cells, and some layers of the cuticle. The technique is complementary to transmission electron microscopy and facilitates the interpretation of results from thin sections. ------------------- Key: 182 Medline: Authors: Hogger CH;Estey RH;Kisiel MJ;Zuckerman BM Title: Surface scanning observations of changes in C. briggsae during aging. Citation: Nematologica 23: 213-216 1977 Type: ARTICLE Genes: Abstract: SEM observations of adult Caenorhabditis briggsae females showed differences between young and old nematodes. In young nematodes the cuticle was generally smooth, whereas in old ones it was wrinkled. Deirids were located at the level of the excretory pore in the lateral field. They were distinct in young nematodes but indistinct in old ones. The oral opening was formed by six lips, which were closed in old nematodes and open in young ones. The vulva possessed two semi-circular lips and was bordered by two lateral flaps. These lips were smooth in young specimens and wrinkled in old ones. Cryofractures of old nematodes showed cavities in the intestinal epithelium corresponding to areas in which age pigment granules normally occur. No such cavities were seen in young nematodes. ------------------- Key: 183 Medline: Authors: Honda H Title: Experimental and cytological studies on bisexual and hermaphroditic free-living nematodes with special reference to the problem of sex. Citation: Journal of Morphology 40: 191-233 1925 Type: ARTICLE Genes: Abstract: Hermaphrodite gonads of Rahbditis elegans can be distinguished in early developmental stages, but oogonia cannot be told from spermatogonia. Certain peculiar males show developmental processes approaching those of hermaphrodites. More eggs are produced by a hermaphrodite than there are sperm with which to fertilize them. Such exhausted hermaphrodites may be mated with males and produce fertile eggs, but convincing evidence of cross-fertilization is lacking. Unmated females of Diplogaster serivora live longer than mated ones, but no difference was found in the males. Sexual instinct seems to be lacking in males of R. dolichura and R. elegans. Hermaphrodites mated with males produce many more male offspring than by self-fertilization, but these do not exhibit sexual instincts. Females produced by cross-fertilization are not pure females, nor have they been found at all in R. elegans or R. dolichura. After fertilization in these two species, both polar bodies are fomed and the pronuclei fuse. Sex is determined by the ------------------- Key: 184 Medline: 80077302 Authors: Horvitz HR;Brenner S;Hodgkin J;Herman RK Title: A uniform genetic nomenclature for the nematode C. elegans. Citation: Molecular & General Genetics 175: 129-133 1979 Type: ARTICLE Genes: Abstract: A uniform system of genetic nomenclature for the nematode Caenorhabditis elegans is described. Convenient ways are specified to designate genes, mutations and strains, and to attempt to avoid name duplications. ------------------- Key: 185 Medline: 78148168 Authors: Hosono R Title: Age dependent changes in the behavior of C. elegans on attraction to Escherichia coli. Citation: Experimental Gerontology 13: 31-36 1978 Type: ARTICLE Genes: Abstract: A method to analyze the response of Caenorhabditis elegans to Escherichia coli as food was devised. Age dependency of the response was purchased with this method chronologically. Although the activity of sinusoidal movement and the utilization of bacteria as food began to decrease rapidly in previous to maximum growth, the attraction potency in young adults was maintained ------------------- Key: 186 Medline: 79107291 Authors: Hosono R Title: Sterilization and growth inhibition of C. elegans by 5-fluorodeoxyuridine. Citation: Experimental Gerontology 13: 369-374 1978 Type: ARTICLE Genes: Abstract: Free living nematodes have often been used for the study of ageing as model organisms, because they have a limited number of somatic cells and a short life-span. The study on ageing has been usually carried out with an age-synchronized population of nematodes. For this purpose, the nematode Caenorhabditis elegans seems to be suitable, because its physiological and genetical characters have been most extensively studied among the nematodes. One of the methods for producing the age-synchrony is the use of a specific inhibitor of DNA synthesis. It has been reported that 5-fluorodeoxyuridine (FdUrd) prevents a maturation of reproductive systems without affecting a growth and a life-span of a nematode Turbatrix aceti. This method is convenient for obtaining a small number of synchronously aged worms. However, recently an apparent increase in cell number during the postembryonic development has been observed in other nematodes. Therefore, it is possible that somatic cells in some nematodes are also sensitive to DNA synthesis inhibitors. The effect of FdUrd on the growth and the production of progeny of C. elegans is as yet unknown. For this report, the effect of FdUrd on the life-cycle of C. elegans has been studied with viable or heat-killed ------------------- Key: 187 Medline: Authors: Hosono R Title: Sinusoidal movement of C. elegans in liquid phase. Citation: Zoologica Magazine 87: 191-195 1978 Type: ARTICLE Genes: Abstract: The nematode Caenorhabditis elegans propagates sinusoidal waves along the body with much higher frequency in a liquid phase than on an agar plate. The sinusoidal movement in a liquid is rhythmic and its frequency varies depending on ages of the nematode or on temperature in the assay. Mutants with affected musculature, show marked differences in their frequency from wild strains. The process of paralysis by an anesthetic and the recovery from the paralytic state are expressed by an alteration of frequency. This method appears to be a useful means for the characterization of chemicals influencing on the behavior and isolation of a new type of mutant. ------------------- Key: 188 Medline: Authors: Hwang SW Title: Freezing and storage of nematodes in liquid nitrogen. Citation: Nematologica 16: 305-308 1970 Type: ARTICLE Genes: Abstract: Free-living nematodes of the genera Aphelenchoides, Panagrellus, Turbatrix, and Caenorhabditis were successfully frozen in heat-sealed glass ampoules using dimethyl sulfoxide as a protectant. After 6 months storage in liquid nitrogen refrigerator (below -160C), living nematodes were recovered after thawing. The nematodes were slowly cooled to -22 +/- 1C and immediately transferred to liquid nitrogen at -196C. ------------------- Key: 189 Medline: 69225355 Authors: Jakstys BP;Silverman PH Title: Effect of heterologous antibody on Haemonchus contortus development in vitro. Citation: Journal of Parasitology 55: 486-492 1969 Type: ARTICLE Genes: Abstract: Double diffusion tests of sera obtained from rabbits immunized with somatic extracts of the free-living nematodes, Caenorhabditis briggsae and C. elegans, resulted in cross-reactions with metabolic and somatic extracts of the sheep parastic stomach worm, Haemonchus contortus. In vitro culture experiments demonstrated that H. contortus development was retarded by the same heterologous antisera. The possibility of complement playing a role in the heterologous immune cross-reactions is suggested. ------------------- Key: 190 Medline: Authors: Jantunen R Title: Moulting of C. briggsae (Rhabditidae). Citation: Nematologica 10: 419-424 1964 Type: ARTICLE Genes: Abstract: The moulting of Caenorhabditis briggsae was observed under axenic conditions in hanging drop cultures. From these observations, and from a statistical analysis of the dimensions of "sheaths" taken from a mass culture, it is concluded that there are four moults. The process of moulting is described. ------------------- Key: 191 Medline: 79214177 Authors: Johnson K;Hirsh D Title: Patterns of proteins synthesized during development of C. elegans. Citation: Developmental Biology 70: 241-248 1979 Type: ARTICLE Genes: Abstract: Two-dimensional gel electrophoresis has been used to analyze proteins synthesized during postembryonic development of the nematode Caenorhabditis elegans. This organism is favorable for these studies because it has a limited number of cells, it is genetically well-defined, and its development is currently under investigation in several laboratories. 35S-labeled E. coli was used for continuous and pulse labeling of C. elegans during its four juvenile larval stages and as a gravid adult. After continuous labeling or pulse labeling for 1 hr, 600-800 individual spots can be resolved on a 2D gel using fluorography and 2 weeks of exposure. Proteins that represent 0.0017% of the total sample can be detected. Exposure for 12 weeks reveals only 100 additional spots even though the films are not saturated. It therefore appears that the frequency distribution of proteins decreases significantly beyond these 800 most abundant proteins that can be frationated on an O'Farrell gel. When the patterns of pulse-labeled proteins of the five developmental stages were compared, 113 proteins could be seen to undergo modulation at one or more of the developmental stages. A maximum number of changes was seen in the transition from the L4 to the adult stages when 11% of the total spots either appeared, disappeared, or changed in intensity. As controls, different preparations of the same developmental stage were compared and revealed considerable fluctuation, 2.6-4.8%. These fluctuations are presumed to be due to variations in growth conditions during culture of the organism. Continuous label experiments reveal a distinct set of proteins that undergo turnover and/or modification during development. Some of these proteins are absent in only one stage, indicating that stable proteins are also modulated. But nearly all of the proteins seen in a continuous label are also seen in a pulse label indicating that most of the major proteins are ------------------- Key: 192 Medline: Authors: Kermarrec A Title: Recherches sur les ennemis du champignon de couche. I. Zoocenose des composts de champignonniere a Agaricus bisporus Lange/ Citation: Annales de Zoologie - Ecologie Animale 5: 425-464 1973 Type: ARTICLE Genes: Abstract: Investigations on the enemies of the cultivated mushroom. I. Study of the zoocenoses of cultivated composts (Agaricus bisporus Lange). The study of zoocenoses of cultivated composts (Agaricus bisporus Lange) and these of graphical and mathematical tools show up an ecologically "extreme" character of these biotopes according to the nematodes. The analysis of the dynamics of the nematodes fauna reveals successions of species, spatial migrations and escaping behaviours, accompagned by phoresy. The relations between nematodes and the biotical and abiotical phases of the medium are compound and discussed. In particular, animal and especially vegetal predatism allows to envisage the adjusting of biological control methods. ------------------- Key: 193 Medline: 80004565 Authors: Kimble J;Hirsh D Title: The postembryonic cell lineages of the hermaphrodite and male gonads in Caenorhabditis elegans. Citation: Developmental Biology 70: 396-417 1979 Type: ARTICLE Genes: Abstract: The ancestry of the cells in the hermaphrodite and male gonadal somatic structures of C. elegans has been traced from the two gonadal somatic progenitor cells (Z1 and Z4) that are present in the newly hatched larvae of both sexes. The lineages of Z1 and Z4 are essentially invariant. In hermaphrodites, they give rise to a symmetrical group of structures consisting of 143 cells, and in males, they give rise to an asymmetrical group of structures consisting of 56 cells. The male gonad can be distinguished from the hermaphrodite gonad soon after the first division of Z1 and Z4. However, the development of Z1 and Z4 in hermaphrodites shares several features in common with their development in males suggesting that the two programs are controlled by similar mechanisms. In the hermaphrodite lineage, a variability in the positions of two cells is correlated with a variability in the lineages of four cells. This variability suggests that cell-cell interaction may play a more significant role in organisms that develop by invariant lineages than has hitherto been considered. None of the somatic structures (e.g., uterus, spermatheca, vas deferens) develops as a clone of a single cell. Instead, cells that arise early in the Z1-Z4 lineage generally contribute descendants to more than one structure, and individual structures consist of descendants ------------------- Key: 194 Medline: Authors: Kimpinski J Title: Nematodes associated with vegetables in Prince Edward Island Canada. Citation: Plant Disease Reporter 59: 37-39 1975 Type: ARTICLE Genes: Abstract: Twenty-five genera of nematodes were identified in six vegetable crops (carrot, pea, broccoli, rutabaga, Brussels sprouts, cauliflower) at fifty-six locations in Prince Edward Island (P.E.I.). Root lesion nematodes, Pratylenchus penetrans, were found in the soil at all locations and accounted for about 19% of the total nematode fauna. Meloidogyne hapla were recovered in only a few samples in low numbers, as were nematodes in the order Dorylaimida which accounted for about 5% of the total population. Non-stylet bearing nematodes made up 55% of the total and most of these were in two genera, Caenorhabditis spp. and Cephalobus spp. Carrot soils harbored the highest number of root lesion nematodes and pea soils had the least; 4726 and 547/kg of dry soil, respectively. Pea roots, however, had 2647/g dry root of these nematodes. No root lesion or other endoparasitic nematodes were recovered from the tap roots of carrots or from rutabagas. Some carrot and pea fields appeared to have lower than average yields where root lesion nematodes were recovered from soil and roots in very high numbers. ------------------- Key: 196 Medline: 75193113 Authors: Kisiel MJ;Castillo JM;Zuckerman LS;Zuckerman BM;Himmelhoch Title: Studies on ageing Turbatrix aceti. Citation: Mechanisms of Ageing & Development 4: 81-88 1975 Type: ARTICLE Genes: Abstract: Morphologic and physiologic changes which occur during senescence in the free-living nematode Turbatrix aceti are described. With age areas of the interchordal hypodermis containing nerve elements thickened, electron-dense aggregates formed within the pseudocoelom and age pigment granules accumulated within the intestinal epithelium. Specific gravity did not change with age. Old nematodes which had reproduced showed increased osmotic fragility, but this change was not observed in virgin females. The parameters characterizing senescence in T. aceti are compared with those of Caenorhabditis briggsae, another nematode being used as a model to study biological ageing. ------------------- Key: 197 Medline: 77115881 Authors: Kisiel MJ;Deubert KH;Zuckerman BM Title: Biogenic amines in the free-living nematode C. briggsae. Citation: Experimental Aging Research 2: 37-44 1976 Type: ARTICLE Genes: Abstract: Dopamine, epinephrine, norepinephrine and serotonin were demonstrated from homogenates of Caenorhabditis briggsae by two-dimensional thin layer chromatography and the identifications confirmed by gas liquid chromatography. In Vitro studies with 14C precursors of these biogenic amines demonstrate the ability of C. briggsae to synthesize each compound. The results provide required preliminary data for studying the neurophysiology of aging utilizing the nematode as a model. ------------------- Key: 198 Medline: 75039050 Authors: Kisiel MJ;Himmelhoch S;Zuckerman BM Title: C. briggsae: Effects of aminopterin. Citation: Experimental Parasitology 36: 430-438 1974 Type: ARTICLE Genes: Abstract: The characteristic features of senescence developed prematurely in Caenorhabditis briggsae treated with the DNA synthesis inhibitor aminopterin at the minimum dosage which inhibits gonad formation. In addition, aminopterin induced other changes which thus far have not been associated with normal aging of C. briggsae. Interpretations of these results are given based on current knowledge of the mode action of aminopterin and an extant theory of aging. ------------------- Key: 199 Medline: Authors: Kisiel MJ;Nelson B;Zuckerman BM Title: Influence of a growth factor from bacteria on the morphology of C. briggsae. Citation: Nematologica 15: 153-153 1969 Type: ARTICLE Genes: Abstract: Several investigators have reported that nutritional or environmental factors induce morphological variations in the "so-called' bacteriophagous nematodes. For example, Nigon & Dougherty described a morphological mutant of the free-living, self-fertilizing, hermaphroditic nematode Rhabditis (Caenorhabditis) briggsae that ensued following heat-treatment of progeny cultured on bacteria. Also Anderson reported that certain diagnostic features of an Acrobeloides sp., specifically the shape of the labial probolae and tail, varied significantly when the nematodes were grown on bacterial cultures as compared to those grown in soil. The current paper describes a consistent morphological variation in Caenorhabditis briggsae grown axenically on a meridic medium containing a growth factor from a bacterium as compared with nematodes reared on a growth factor from liver extract. ------------------- Key: 200 Medline: Authors: Kisiel MJ;Nelson B;Zuckerman BM Title: Effects of DNA synthesis inhibitors on C. briggsae and Turbatrix aceti. Citation: Nematologica 18: 373-384 1972 Type: ARTICLE Genes: Abstract: The effects of three DNA synthesis inhibitors on axenically grown Caenorhabditis briggsae and Turbatrix aceti were evaluated. Lower dosages of aminopterin sometimes prevented vagina formation and the eggs hatched within the oviduct. Concentrations of aminopterin, 5-fluorodeoxyuridine and hydroxyurea which prevented reproduction, caused significant growth inhibition, prevented maturation past the third larval stage, and reduced longevity. A difference in physiologic state was induced by the inability of aminopterin treated Caenorhabditis briggsae to adjust to osmotic pressures tolerated by untreated nematodes. These studies indicate the difficulties inherent in utilizing age-synchronous nematode cultures produced by the application of DNA ------------------- Key: 202 Medline: Authors: Kisiel MJ;Zuckerman BM Title: Effects of centrophenoxine on the nematode C. briggsae. Citation: Age 1: 17-20 1978 Type: ARTICLE Genes: Abstract: Concentrations below 13.6 mM centrophenoxine in the culture medium had no inhibitory effect on several developmental parameters of Caenorhabditis briggsae: specifically growth, fecundity and longevity. The effects on two parameters which characterize senescence in this nematode, increased osmotic fragility and increased specific gravity, were also evaluated. Above 6.8 mM old nematodes showed significantly less osmotic fragility and reduced specific gravity. Evaluation of the effects on negative charge of the cuticle surface membrane showed that neither 6.8 mM nor 17 mM affected negative surface charge density. Electron microscope studies showed that age-pigment accumulation was significantly retarded by a concentration of 6.8 mM centrophenoxine. It is suggested that the specific gravity effect is correlated with the retardation of lipofuscin accumulation with age. If this proves correct, then specific gravity will be another parameter for measuring the effects of centrophenoxine on aging tissues. This study also demonstrated that the effects of drugs on the retardation of age pigment formation can be visualized in three weeks by utilizing C. briggsae as a model. ------------------- Key: 203 Medline: 78049700 Authors: Klass MR Title: Aging in the nematode C. elegans: Major biological and environmental factors influencing life span. Citation: Mechanisms of Ageing & Development 6: 413-429 1977 Type: ARTICLE Genes: Abstract: The free-living nematode Caenorhabditis elegans is an excellent experimental system for the study of aging. The present study identifies some of the major biological and environmental factors influencing life span as a prelude to more detailed genetic and biochemical analyses. Life span can be altered during any part of the life cycle by a change in either temperature or food concentration. Parental age and parental life span both have relatively small effects on progeny life span. The nematode accumulates fluorescent pigment resembling lipofuscin, and becomes less sensitive to ultra-violet radiation as it ------------------- Key: 204 Medline: 76174434 Authors: Klass M;Hirsh D Title: Nonaging developmental variant of C. elegans. Citation: Nature 260: 523-525 1976 Type: ARTICLE Genes: Abstract: The study of mechanisms affecting the rate of ageing can be facilitated by naturally occurring phenomena, innate to some organisms, that enable the species to retard its ageing rate and extend its life span. Such a phenomenon exists in certain species of nematode. Larval forms of the free-living soil nematode, Caenorhabditis elegans, possess the ability to enter a semi-dormant, quiescent state referred to as the dauer larval stage (German, "enduring" larva). Newly hatched larvae of C. elegans undergo four larval stages (L1-L4) punctuated by moulting. If larvae are starved, they will enter the dauer state during the second larval moult. At this time, the old cuticle is replaced by a special, relatively impermeable cuticle unique to dauer larvae. ------------------- Key: 205 Medline: 77003912 Authors: Klass M;Wolf N;Hirsh D Title: Development of the male reproductive system and sexual transformation in the nematode C. elegans. Citation: Developmental Biology 52: 1-18 1976 Type: ARTICLE Genes: tra-2 Abstract: The small free-living nematode Caenorhabditis elegans is usually found as a hermaphrodite, but occasionally true males appear in the population. This study provides an account of gonadogenesis in the normal male and in a mutant that is a temperature-sensitive sex transformer. Male and hermaphrodite gonads develop from morphologically identical primordia. The small primordial gonad lies on the ventral side of the worm in the coelomic cavity. The gonadial primordium contains four nuclei at parturition. As this primordium develops in a hermaphrodite, it produces a double-armed, mirror symmetrical gonad that produces first sperm and then eggs. In the male, however, this primordium develops into an asymmetrical structure composed of a ventrally located testis, a loop region, a seminal vesicle, and a vas deferens. The male gonad presents a linear sequence of nuclei in successive stages of spermatogenesis with a mitotic region in the testis, followed by clearly distinguishable stages of meiosis throughout the loop region to the seminal vesicle. A temperature-sensitive sex transformer mutant, tsB202, has been isolated. tsB202 carries an autosomal recessive mutation in linkage group II that at restrictive temperature transforms an XX hermaphrodite into a phenotypic male, complete with a normal male gonad and vestigial external genitalia. These transformed males are classified as pseudomales because they do not exhibit mating behavior. Temperature shift experiments have determined the specific temporal sequences of gonadogenesis, oogenesis, and spermatogenesis. Proper manipulation of the temperature regimen causes the production of intersexes. In one intersex, a male gonad complete with sperm, seminal vesical, and vas deferens also contains oocytes. In another intersex produced by the complementary temperature shift, a hermaphrodite-shaped gonad develops that produces only sperm and no oocytes. ------------------- Key: 206 Medline: 79192248 Authors: Klass MR;Wolf N;Hirsh D Title: Further characterization of a temperature-sensitive transformation mutant in C. elegans. Citation: Developmental Biology 69: 329-335 1979 Type: ARTICLE Genes: tra-2 Abstract: The temperature-sensitive sex transformer tra-2(b202)II of the nematode Caenorhabditis elegans causes the tranformation of genotypically hermaphrodite worms into phenotypic males and sterile intersexes at restrictive temperature. In this note, we show that the entire gonad structure is transformed and that oocyte development is autonomous of the form of the gonad and of the presence of a cellular sheath. Four oocyte-specific proteins are present in male intersexes that produce oocytes but are lacking in transformed males and hermaphrodite intersexes ------------------- Key: 207 Medline: Authors: Klefenz HF;Zuckerman BM Title: Review: a comparative analysis of studies of enzyme changes with age, with comments on possible sources of error. Citation: Age 1: 60-67 1978 Type: REVIEW Genes: Abstract: Studies on enzyme changes during aging from rodents, nematodes and tissue culture cells have been reviewed. In the rodent and tissue culture studies, conflicting results on aging of specific enzymes have been reported from several laboratories. These works have been analyzed, with the aim of stressing the different findings and analyzing possible reasons for the discrepancies. With regard to the nematode studies, the authors suggest that the examination of the concept of general failure of protein synthesis mechanisms as a basic cause of cellular senescence requires more rigorous methods than have been utilized in previous studies. ------------------- Key: 208 Medline: Authors: Korner H Title: Die Nematoden-fauna des vergehenden Holzes und ihre Beziehungen zu den Insekten. Citation: Zoolyst 82: 245-353 1954 Type: ARTICLE Genes: Abstract: ------------------- Key: 209 Medline: Authors: Kreis HA Title: Freilebende terristrische Nematoden aus der Umgebung von Peking (China). Citation: Zoologischer Anzeiger 84: 283-294 1929 Type: ARTICLE Genes: Abstract: ------------------- Key: 210 Medline: Authors: Kreis HA Title: A. Freilebende terrestrische Nematoden aus der Umgebung von Peking (China) II. Citation: Zoologischer Anzeiger 87: 67-87 1930 Type: ARTICLE Genes: Abstract: ------------------- Key: 211 Medline: Authors: Kreis HA;Faust EC Title: Two new species of Rhabditis (Rhabditis macrocerca & R. clavopapillata) associated with dogs and monkeys in experimental Strongyloides studies. Citation: Transactions of the American Microscopical Society 52: 162-172 1933 Type: ARTICLE Genes: Abstract: From time to time during our studies on experimental Strongyloides infections, freshly passed stools of dogs have been contaminated with species of Rhabditis. At first it was believed that the contaminations resulted from improper sterilization of the Petri dishes used in collecting the feces, but after this possibility was eliminated the worms appeared with equal consistency. Sterilization of the cages in which the animals were housed also failed to reduce the contamination. Studies were then made of the animals themselves and it was found that the worms were developing in abundance among the perianal hairs, particularly in those dogs which had loose bowel movements. To a lesser extent the hairs of the abdomen, legs and even the face were also discovered to be favorable breeding places for these rhabditids. Thorough cleansing of the dogs externally with cresol solutions reduced the contamination appreciably but did not completely eliminate ------------------- Key: 212 Medline: 78239496 Authors: Krieg C;Cole T;Deppe U;Schierenberg E;Schmitt D;Yoder B;von Ehrenstein G Title: The cellular anatomy of embryos of the nematode C. elegans. Analysis and reconstruction of serial section electron micrographs. Citation: Developmental Biology 65: 193-215 1978 Type: ARTICLE Genes: Abstract: As described from light microscopy, embryogenesis of the free-living soil nematode Caenorhabditis elegans follows a strictly determinate cleavage pattern, producing a newly hatched juvenile with about 550 cells arranged quite predictably. In this communication we present results on the electron microscopy of C. elegans embryos and introduce methods for fixing, embedding, and serially sectioning embryos encased in the egg shell. Fixation at elevated temperature either with osmium tetroxide alone or with glutaraldehyde followed by osmium tetroxide gives reproducible results with embryos in all developmental stages so far tested, from the fertilized egg to hatching. Eighteen wild-type eggs at various stages have been sectioned to date. We have achieved using newly developed procedures for analyzing electron micrographs of serial sections detailed reconstructions of the cellular anatomy of complete embryos of a metazoan organism. Three-dimensional serial section reconstructions were made with a computer system. We characterize and map the 24 cells of an early-stage embryo in this report. Additionally, we can specify the lineage history of all cells of this embryo by matching the reconstructed three-dimensional arrangement of this series to a living embryo at this stage, where cell lineage has been observed with Nomarski optics and analyzed using videotape. In addition, cytoplasmic and nuclear morphological features such as incomplete membranes between sister cells, rounding-off of the cytoplasm, and chromatin condensation patterns have been correlated with cell division. Mapping of such structures presents a new method by which supplementary lineage information can be obtained directly ------------------- Key: 214 Medline: 77119003 Authors: Lewis JA;Hodgkin JA Title: Specific neuroanatomical changes in chemosensory mutants of the nematode C. elegans. Citation: Journal of Comparative Neurology 172: 489-510 1977 Type: ARTICLE Genes: che-1 che-2 che-3 che-5 che-6 che-7 mec-1 mec-2 mor-1 mor-2 unc-7 vab-1 vab-2 vab-3 vab-5 Abstract: Eight of nineteen chemotactic mutants of the nematode, Caenorhabditis elegans have morphological defects in the sensory endings of neurons at the tip of the head. The mutants were obtained as worms swimming away from attractant or found amongst male potency mutants or mutants exhibiting erractic behavior. The nineteen mutants fall into at least twelve complementation groups. Mutants E1034 and E1035, alleles of che-1, show morphological alterations in the sensory endings of amphidial neurons and inner labial type 2 neurons, both prospective chemosensory neurons. Both mutants contain non-complementing ts sterile mutations linked to the chemosensory mutation. E1066 shows abnormalities in all the sheath cells associated with the sensory neurons and in the bundling pattern of the amphidial neurons. E1126 is structurally abnormal only in the sensory endings of inner labial type 2 neurons, supporting a chemosensory role for these neurons. E1033 (che-2) and E1124 (che-3) cause defects in the ciliary structure of all but one type of ciliated sensory neuron in the head. E1062 is grossly defective in head structure and the structure of the male copulatory organ, suggesting these opposite ends of the nematode rich in sensory structures share gene functions in embryogenesis. Our study illustrates the possibilities for genetic dissection of the development of a small set of nerves in a simple ------------------- Key: 215 Medline: 76209326 Authors: Liu A;Rothstein M Title: Nematode biochemistry XV. Enzyme changes related to glycerol excretion in C. briggsae. Citation: Comparative Biochemistry & Physiology 54B: 233-238 1976 Type: ARTICLE Genes: Abstract: 1. In the free-living nematode, Caenorhabditis briggsae, several enzymes involved in glycolysis change markedly in activity when the organism is incubated under different nutritional conditions. 2. Activities of phosphofructokinase and glycerol phosphate dehydrogenase increase sharply in worms incubated in "growth medium". 3. After incubation in buffer, the organisms show higher activities in aldolase, fructose-1,6-diphosphatase and glycerol phosphate dehydrogenase in the reverse direction (glycerol phosphate as substrate). 4. These shifts in enzyme levels can explain the differences in excretion products under both sets of conditions. 5. When C. briggsae is incubated with [2-14C]-acetate in buffer, glucose is the main radioactive product, but trehalose and small amounts of glycerol and fructose are also found; in whole medium, glycerol is most highly labeled, though detectable amounts of glucose and trehalose are present. 6. Extracts of the worms yield similar products in both cases, namely, trehalose and glucose along with small amounts of ribose and glycerol. ------------------- Key: 217 Medline: Authors: Lower WR;Buecher EJ Title: Axenic culturing of nematodes: an easily prepared medium containing yeast extract. Citation: Nematologica 16: 563-566 1970 Type: ARTICLE Genes: Abstract: An aqueous extract from ruptured baker's yeast added as a required supplement to a soy-peptone, Bacto-yeast solution constitutes an easily prepared, inexpensive and stable medium for the axenic culture of some nematodes. Cell walls and unbroken cells were removed by centrifugation and the supernatant was sterilized by filtration. Medium containing the supplement supported growth of three species of free-living nematodes and two species of Neoaplectana, a nematode parasite of insects. ------------------- Key: 218 Medline: 67011548 Authors: Lower WR;Hansen EL;Yarwood EA Title: Assay of a proteinaceous growth factor required for maturation of the free-living nematode, C. briggsae. Citation: Journal of Experimental Zoology 161: 29-36 1966 Type: ARTICLE Genes: Abstract: The time to maturation of a free-living, protandrous, self-fertilizing nematode, Caenorhabditis briggsae, was used to assay preparations of a proteinaceous growth factor and the effects of different treatments. Development was measured as time of the production of F1 offspring against concentration of growth factor. The data were tranformed to the reciprocal of F1 time against logarithm of the dose and analyzed by regression analysis. Estimates were made of the dose of growth factor required for maturation in seven days, and relative potencies were determined for assays whose regression coefficients did not significantly differ from one another. The dose of growth factor required for maturation in seven days fell within range from 8 ug/ml to 28 ug/ml. The methods of treatment for activation of growth factor studied were freezing overnight at -23C, dialysis to low phosphate, and addition of the sucrose polymer, FICOLL. Reproducibility of results was shown for controls made for each experiment and for assays repeated at different times. Inocula of various numbers of larvae per tube, 1 through 30, were compared; significant increase in maturation time occurred when inocula were ------------------- Key: 219 Medline: Authors: Lower WR;Hansen EL;Yarwood EA Title: The use of nematodes cultured axenically on defined medium for biological studies. Citation: American Naturalist 100: 367-370 1966 Type: ARTICLE Genes: Abstract: Nematodes cultured axenically (bacteria free) on defined media represent useful additions to the list of organisms available for genetic studies. Axenic culturing eliminates an important source of confusion, which is present in bacterial cultures: metabolic and other changes in the bacteria themselves. The use of defined instead of crude media allows for more precise analyses of growth and development, and permits determination of the nutrient factors needed. ------------------- Key: 220 Medline: 71292582 Authors: Lower WR;Hansen EL;Yarwood EA Title: Selection for adaptation to increased temperatures in free-living nematodes. Citation: Life Sciences 7: 139-146 1968 Type: ARTICLE Genes: Abstract: Adaptation to high temperature, whether a physiological adaptation of the individual or genetic adaptation of a population, represents one of the adjustments which organisms must make to their environment. The current report represents a time cross-sectional examination of a continuing experiment that deals with the progress in adaptation to high temperature and examination of some of the differences observed. Populations in thin film continuous cultures were incubated at increasing temperatures, and at intervals the reproductive characteristics of individuals were determined. Two species of free-living nematodes were used which differ in their mating system and may differ in their amount of genetic variability: Panagrellus redivivus, a dioecious species, and Caenorhabditis briggsae, a protandrous, self-fertilizing hermaphrodite which produces an occasional male. Populations of P. redivivus may have more genetic variability than populations of C. briggsae. C. briggsae, though largely self-fertilizing, cannot, a priori, be considered highly homozygous, since facultative inbreeding, balanced polymorphism and heterozygote superiority are capable of maintaining genetic variability. ------------------- Key: 223 Medline: 74098203 Authors: Lu NC;Hieb WF;Stokstad ELR Title: Accumulation of formimino-L-glutamic acid in the free-living nematode C. briggsae as related to folic acid Citation: Proc. Society for Experimental Biology & Medicine 145: 67-69 1974 Type: ARTICLE Genes: Abstract: Formimino-L-glutamic acid (FIGLU), which is an intermediate of histidine degradation, is excreted in large amounts in the urine of folic acid deficient rats and humans. Urinary excretion of FIGLU can be raised by increasing the level of dietary histidine in rats. Luhby and Cooperman have used the "histidine load" test for diagnosis of folic acid deficiency in humans. However, very little is known about histidine degradation in folic acid deficiency in lower animals. The present study was conducted with the axenically grown free-living nematode, Caenorhabditis briggsae, which requires folic acid for reproduction. ------------------- Key: 224 Medline: 76176610 Authors: Lu NC;Hieb WF;Stokstad ELR Title: Effect of vitamin B-12 & folate on biosynthesis of methionine from homocysteine in the nematode C. briggsae. Citation: Proc. Society for Experimental Biology & Medicine 151: 701-706 1976 Type: ARTICLE Genes: Abstract: The roles of dietary vitamin B12 and folic acid in methionine biosynthesis from homocysteine were first observed in higher animals. Jukes, Stokstad, and Broquist noted that the growth of vitamin B12-deficient chicks were increased by either methionine or homocysteine and vitamin B12 but not by homocysteine alone. It was also reported that rats were able to utilize homocysteine in lieu of methionine when folic acid or choline was added to the diet. In microorganisms, Escherichia coli is known to possess two alternative pathways for methionine biosynthesis: the vitamin B12-dependent pathway and the vitamin B12-independent one. In the present study, we show evidence that dietary vitamin B12 and folic acid were required for the biosynthesis of methionine from homocysteine in an axenic free-living nematode, Caenorhabditis briggsae. Information related to biochemical nutrition in invertebrates in sparse. Therefore, this study has particular relevance to the fields of comparative nutrition and biochemistry. ------------------- Key: 225 Medline: 78226453 Authors: Lu NC;Hubenberg G Jr;Briggs GM;Stokstad ELR Title: The growth-promoting activity of several lipid-related compounds in the free-living nematode C. briggsae. Citation: Proc. Society for Experimental Biology & Medicine 158: 187-191 1978 Type: ARTICLE Genes: Abstract: During the past decade, much progress has been made in the search of growth factors for the free-living nematode, C. briggsae. In 1968 Hieb and Rothstein showed a sterol requirement in C. briggsae. Hieb, Stokstad and Rothstein further reported a requirement for heme in 1970. These discoveries have led to the use of heme and sterol supplements in a chemically defined medium, the C. briggsae Maintenance Medium (CbMM), for the cultivation of C. briggsae. For many years another unidentified growth factor has been known to be required for C. briggsae. A variety of proteinaceous sources has been used to provide this unidentified growth factor(s), including commercially available products such as soy peptone, egg albumin, and casamino acids, "defined" proteins such as insulin and TMV-protein, and yeast ribosomes. However, attempts at isolating the unidentified growth factor(s) from the proteinaceous sources have not been successful yet. Vanfleteren has recently suggested that an acid-precipitated hemin could replace the proteinaceous growth factor in C. briggsae due to the stimulation of phagocytosis by the precipitates. Also, Pinnock, Shane and Stokstad reported that a dipeptide (leu-phe) can partially replace the growth factor activity of casamino acids (acid hydrolysate of casein). ------------------- Key: 226 Medline: Authors: Lu NC;Newton C;Stokstad ELR Title: The requirement of sterol and various sterol precursors in free-living nematodes. Citation: Nematologica 23: 57-61 1977 Type: ARTICLE Genes: Abstract: The quantitative sterol requirements were studied in C. briggsae, C. elegans (Be), C. elegans (Br), and T. aceti. It was shown that all four nematodes had similar minimal sterol requirements (0.1-2.0 ug/ml) and toxicity appeared in T. aceti at 50 ug/ml. Cholesterol and five precursors were tested for population growth. We found that acetic acid, DL-mevalonic acid lactone, and farnesol did not support population growth; while squalene, lanosterol, and cholesterol supported significant population growth in all four nematodes. Our results suggest that the major metabolic block in the pathway of sterol biosynthesis occurs between the step of farnesol and squalene. ------------------- Key: 228 Medline: Authors: Lyons JM;Keith AD;Thomason IJ Title: Temperature-induced phase transitions in nematode lipids and their influence on respiration. Citation: Journal of Nematology 7: 98-104 1975 Type: ARTICLE Genes: Abstract: Temperature-induced phase transitions estimated by electron spin resonance (ESR) technique were observed in the lipids of several nematode species. In both Meloidogyne javanica and Caenorhabditis elegans, there was a phase transition in their phospholipids from a liquid-crystalline state to a solid gel state at about 10 C. Aphelenchus avenae also had a phase transition, but at about 20 C. With this species, the spin-label motion parameters indicated the transition was from the liquid-crystalline state below 20 C to a more liquid or disordered state above 20 C. Anguina tritici and Meloidogyne hapla, in contrast, had no phase transitions over the entire temperature range studied. Each phase transition detected by ESR was reflected in the respiratory rates of the nematodes, and the temperature of the transition coincides with the environmental adaptation of these species. ------------------- Key: 230 Medline: 79084145 Authors: Mackenzie JM Jr;Garcea RL;Zengel JM;Epstein HF Title: Muscle development in C. elegans mutants exhibiting retarded sarcomere construction. Citation: Cell 15: 751-762 1978 Type: ARTICLE Genes: unc-52 Abstract: We have studied the structural changes within the body-wall muscle cells of Caenorhabditis elegans during postmitotic development. In wildtype, the number of sarcomeres progressively increases, and each sarcomere appears to grow in length and depth continuously during this period. In mature wild-type cells, the anterior-most body-wall muscle cells have 6--7 sarcomeres; the rest have 9--10 sarcomeres per cell. Twelve mutants in the unc-52 II gene exhibit markedly retarded sarcomere construction and progressive paralysis. Several unc-52 mutants, such as the severely paralyzed SU200, produced only 2--3 sarcomeres per body-wall muscle cell, while the other mildly paralyzed unc-52 mutants, such as SU250, build 3--4 sarcomeres per muscle cell. Other structures such as the pharynx and even the noncontractile organelles of the body-wall muscle cells do not appear to be structurally or functionally altered. The unc-52 body-wall sarcomeres become moderately disorganized as they are outstripped by cell growth; sufficient order is preserved, however, so that the majority of thick and thin filaments still interdigitate. The myosin heavy chains of SU200 body-wall muscle fail to accumulate normally, while the pharyngeal myosin heavy chains do not appear to be specifically affected. This biochemical result correlates well with the specificity of morphological changes in the mutant. A model is discussed in which the biochemical and morphological deficits are explained by a simple regulatory mechanism. ------------------- Key: 231 Medline: 79063844 Authors: Mackenzie JM Jr;Schachat F;Epstein HF Title: Immunocytochemical localization of two myosins within the same muscle cells in C. elegans. Citation: Cell 15: 413-419 1978 Type: ARTICLE Genes: unc-54 Abstract: Nematodes synthesize two major classes of myosin heavy chains. These heavy chains associate to form only homodimeric myosin molecules, and these myosin homodimers are antigenically different from one another. The two myosins may be designated unc-54 myosin, since this species is altered in mutants of the unc-54 locus, and non-unc-54 myosin, since this class is not affected in unc-54 mutants. We present here experiments in which specific anti-myosin IgG and anti-unc-54 myosin IgG are used to locate the two myosins within the same body-wall muscle cells of Caenorhabditis elegans. These results are necessary for further evaluation of the possible functions of the two myosin homodimers in the thick filaments of these muscles. Myosin can be localized to all body-wall and pharyngeal muscle cells using anti-myosin antibody. In longitudinal sections of body-wall muscle, the staining with anti-myosin coincides with the birefringence of A bands that contain thick filaments. Anti-unc-54 myosin stains all body-wall A bands uniformly but does not react with the pharynx. This result demonstrates that unc-54 is located exclusively in body-wall muscle cells of the wild-type strain N2. Non-unc-54 myosin is localized with anti-myosin in all body-wall muscle cells of the unc-54 null mutant E190, as expected; however, unc-54 myosin could not be detected by anti-unc-54 myosin antibody in this mutant. Since we can localize unc-54 myosin and non-unc-54 myosin in all body-wall muscle cells of wild-type and E190, respectively, we conclude that the two myosins must be present in the same muscle cells. In addition, since unc-54 myosin is located in all body-wall A bands, at least some sarcomeres must contain both myosins. This conclusion is consistent with the observations of Garcea, Schachat and Epstein that wild-type and E190 synthesize similar amounts of non-unc-54 myosin. Within the limits of resolution of our methods, unc-54 myosin is distributed throughout body-wall A bands. We conclude, therefore, that the majority of thick filaments within these A bands must contain unc-54 myosin along their entire length. Possible roles for unc-54 and non-unc-54 myosins in the assembly and organization of thick filaments are discussed. ------------------- Key: 232 Medline: 78094402 Authors: MacLeod AR;Waterston RH;Brenner S Title: An internal deletion mutant of a myosin heavy chain in C. elegans. Citation: Proceedings of the National Academy of Sciences USA 74: 5336-5340 1977 Type: ARTICLE Genes: unc-54 Abstract: unc-54 I is the structural gene for a myosin heavy chain present in a major fraction of the total myosin of Caenorhabditis elegans. The allele e675, which possesses a normal amount of myosin but fails to assemble thick filaments, has been shown previously to contain a novel heavy chain of molecular weight 2 X 10*5, shorter by 10*4 than the wild-type (N2) unc-54 gene product. The structural alteration of the E675 heavy chain is an internal deletion of 10*4 molecular weight near the COOH terminus of the molecule. This has been determined by mapping the partial digestion products of heavy chain fragments labeled specifically at the NH2 termini. ------------------- Key: 233 Medline: 78007960 Authors: MacLeod AR;Waterston RH;Fishpool RM;Brenner S Title: Identification of the structural gene for a myosin heavy-chain in C. elegans. Citation: Journal of Molecular Biology 114: 133-140 1977 Type: ARTICLE Genes: unc-54 Abstract: Mutants in the unc-54 gene of Caenorhabditis elegans have been characterized by cyanylation and sodium dodecyl sulphate/polyacrylamide gel electrophoresis of the total myosin present in each mutant. In the recessive mutants lacking a major fraction of the total myosin, the high molecular weight doublet of 15 X 10*4 and 14 X 10*4 which dominates the cyanylation pattern of the total wild-type myosin is absent. In the mutant E675, which possesses a novel heavy-chain with a molecular weight of 2 X 10*5, each component of the cyanylation doublet is reduced by 10*4 daltons, indicating that the doublet is derived from partial cleavage of a single polypeptide chain. This suggests that unc-54 is the structural gene for a myosin heavy-chain present in a major fraction of the total ------------------- Key: 235 Medline: Authors: Manning A Title: The place of genetics in the study of behaviour. Citation: "Growing Points in Ethology" Conference, Cambridge, England, 1975. Bateson PPG and Hinde RA (eds), Cambridge University Press, NY. : 327-343 1975 Type: REVIEW Genes: Abstract: Studies in behaviour genetics have covered a wide field: motivation, development, sensory capacities, intelligence, learning, evolution, neuromorphology and neurochemistry have all been approached using genetic techniques, and there are probably others. Whilst it is at present impossible to construct any unities one must accept that many such studies have as their common aim one of the most fundamental problems in biology: how is behavioral potential encoded in genetic terms and expressed in the course of development? The relative enormity of this problem is often matched by its inaccessibilty. It cannot be claimed that there is any agreed view of the way forward and much of the work has frankly to be opportunistic-seizing on some favourable material or a useful new analytical technique to gain a limited objective. Consequently, behaviour genetics often presents a confusing picture of numerous disjointed studies, with ------------------- Key: 236 Medline: Authors: Marks CF Title: Respiration responses of a Caenorhabditis sp. and Aphelencus avenae to the nematicide 1,2-dibromoethane Citation: Journal of Nematology 3: 113-118 1971 Type: ARTICLE Genes: Abstract: The respiration rate of third stage larvae of Caenorhabditis sp. exposed to 0.53 X 10(-2) M EDB was 120% greater than in untreated checks and was highest shortly after the exposure began. Similarly-treated third- and fourth-stage Aphelenchus avenae exhibited no marked respiratory response. Different responses of these animals to EDB probably reflect basic physiological differences ------------------- Key: 237 Medline: Authors: Marks CF;Sorensen O Title: Measurement of nematode respiration with the biological oxygen monitor. Citation: Journal of Nematology 3: 91-92 1971 Type: ARTICLE Genes: Abstract: Cartesian Diver and manometric techniques have frequently been used to measure the respiration rates of nematodes. However, the sensitivity and ease of operation of the polarographic oxygen-sensing equipment currently available offers a technique of great future value to plant nematologists. Our recent experience with the YSI Model 53 Biological Oxygen Monitor (Yellow Springs Instrument Co., Yellow Springs, Ohio 45387) has shown it is quite satisfactory for measuring the respiration rates of a Caenorhabditis sp. and Aphelenchus avenae Bastian...... ------------------- Key: 239 Medline: Authors: Maupas E Title: Modes et formes de reproduction des nematodes. Citation: Archives de Zoologie Experimentale et Generale 8: 463-624 1900 Type: ARTICLE Genes: Abstract: ------------------- Key: 240 Medline: Authors: Maupas E Title: Essais d'hybridisation chez les nematodes. Citation: Bulletin Biologique de la France et de la Belgique 52: 466-498 1918 Type: ARTICLE Genes: Abstract: In French. ------------------- Key: 241 Medline: 80047782 Authors: Meneely PM;Herman RK Title: Lethals, steriles and deficiencies in a region of the X chromosome of C. elegans. Citation: Genetics 92: 99-115 1979 Type: ARTICLE Genes: let-1 let-2 let-3 let-4 let-5 let-6 let-7 let-9 let-10 let-11 let-12 let-14 let-16 unc-3 eDf2 mnDf1 mnDf2 mnDf5 mnDf6 mnDf7 mnDf9 mnDf10 mnDf13 mnDf15 mnDf18 mnDf20 mnDf21 Abstract: Twenty-one X-linked recessive lethal and sterile mutations balanced by an unlinked X-chromosome duplication have been identified following EMS treatment of the small nematode, Caenorhabditis elegans. The mutations have been assigned by complementation analysis to 14 genes, four of which have more than one mutant allele. Four mutants, all alleles, are temperature-sensitive embryonic lethals. Twelve mutants, in ten genes, are early larval lethals. Two mutants are maternal-effect lethals; for both, oocytes made by mutant hermaphrodites are rescuable by wild-type sperm. One of the maternal-effect lethals and two larval lethals are allelic. One mutant makes defective sperm. The lethals and steriles have been mapped by recombination and by complementation testing against 19 deficiencies identified after X-ray treatment. The deficiencies divide the region, about 15% of the X-chromosome linkage map, into at least nine segments. The deficiencies have also been used to check the phenotypes of hemizygous lethal and ------------------- Key: 242 Medline: 79100296 Authors: Messner B;Kerstan U Title: The histochemical evidence of peroxidase in invertebrate animals (nematoda and insecta). Citation: Acta Histochemica 62: 244-253 1978 Type: ARTICLE Genes: Abstract: In 15 species of nematodes and 3 species of insects an activity of peroxidase was proofed histochemically in various organs and cells using the benzidine-method. ------------------- Key: 244 Medline: 79089359 Authors: Mitchell DH;Stiles JW;Santelli J;Sanadi DR Title: Synchronous growth and aging of C. elegans in the presence of fluorodeoxyuridine. Citation: Journal of Gerontology 34: 28-36 1979 Type: ARTICLE Genes: Abstract: Fluorodeoxyuridine (FUdR), an inhibitor of DNA synthesis, was examined for its ability to prevent a synchronous population of C. elegans from reproducing without otherwise interfering with the organism's post-maturational development and aging. When a synchronized population was exposed to 400 micrometer FUdR just as the population reached sexual maturity, the FUdR induced complete sterility within five hours by preventing eggs from hatching. Any larvae that hatched from eggs made before the FUdR was added remained small in the presence of FUdR and were easily removed by filtration or sedimentation. FUdR-sterilized adults showed no morphological abnormalities. Age-associated changes seen in controls also occurred in FUdR-treated worms, including atrophy of the gonads, increased pigmentation, sluggishness and increased transparency. Life span was not shortened by FUdR treatment. Our observations suggest that treatment with FUdR under carefully controlled conditions is a reasonable way to maintain synchronously aging populations of C. ------------------- Key: 245 Medline: Authors: Moerman DG;Baillie DL Title: Genetic organization in C. elegans: Fine-structure analysis of the unc-22 gene. Citation: Genetics 91: 95-104 1979 Type: ARTICLE Genes: unc-22 Abstract: Fine-structure analysis of the unc-22 gene of Caenorhabditis elegans has revealed a number of sites that are separable by recombination. Eight new ethyl methanesulfonate-induced recessive mutations of the unc-22 gene have been isolated. Using these new alleles, as well as e66, a number of separable sites have been identified and positioned relative to one another. The map distances obtained are found to be comparable to those associated with intragenic recombination in Drosophila melanogaster, indicating that genetic fine-structure analysis is feasible in Caenorhabditis elegans. Evidence of possible gene conversion is presented. A preliminary estimate of the unc-22 gene size is 2.4 X 10(-2) map units. ------------------- Key: 247 Medline: Authors: Monoson HL;Williams SA Title: Endoparasitic nematode-trapping fungi of Mason State Citation: Mycopathologia et Mycologia Applicata 49: 177-183 1973 Type: ARTICLE Genes: Abstract: An initial survey involving the endoparasitic nematode-trapping fungi of Mason State Forest in Illinois was conducted from 15 May to 26 July 1971. Three endoparasitic forms were isolated from the soil samples collected; one non-endoparasitic form was also isolated. Soil pH's and soil nutrient levels were determined for the investigation period. ------------------- Key: 248 Medline: Authors: Monoson HL;Galsky AG;Stephano RS Title: Studies on the ability of various nematodes to induce trap formation in a nematode-trapping fungus Monacrosporium doedycoides. Citation: Nematologica 20: 96-102 1974 Type: ARTICLE Genes: Abstract: Nemin extracted from five different species of nematodes induced the production of predaceous structures by the nematode-trapping fungus, Monacrosporium doedycoides. Quantitative differences in the ability of the different nematodes to induce trap formation were noted. The RNA synthesis inhibitor 6-methyl purine when applied at the same time with the various nemins completely inhibited trap formation by the fungus. Application of the 6-methyl purine 1 hour after the addition of the various nemins had no effect on the number of traps formed. Two compounds that inhibit normal protein synthesis (5-fluorouracil and p-flourophenylalanine) also exhibited a similar trap inhibition effect. The mechanism of nemin-induced trap formation in M. doedycoides seemd to be at the level of transcription. ------------------- Key: 250 Medline: Authors: Mulvey RH Title: Oogenesis in some free-living nematodes. Citation: "Nematology." Sasser JN and Jenkins WR (eds), University of North Carolina Press, Chapel Hill. : 321-322 1960 Type: REVIEW Genes: Abstract: I would like to introduce my lecture on this subject with a brief consideration of meiosis in the female. The oogonial cells in the anterior part of the ovary in a nematode are small and multiply by mitosis. As they move down the ovary they increase in size with corresponding increase in the size of the nucleus. The chromatin is a single spherical mass located in the center of the nucleus. Eventually the chromatin mass is resolved into individual chromosomes. During prophase of meiosis the homologous chromosomes come together. All diploid cells possess identical chromosomes with the exception of the sex chromosomes and at synapsis these homologous chromosomes pair or come together. Paternal and maternal gametes each contribute a complement of identical chromosomes. ------------------- Key: 251 Medline: 76164376 Authors: Murfitt RR;Vogel K;Sanadi DR Title: Characterization of the mitochondria of the free-living nematode, C. elegans. Citation: Comparative Biochemistry & Physiology 53B: 423-430 1976 Type: ARTICLE Genes: Abstract: 1. Conditions are discussed for obtaining population levels of 200,000/ml in 6 days using axenic cultures of the nematode, Caenorhabditis elegans. Lifespan and growth data under these conditions are presented. 2. An isolation procedure which results in high quality mitochondria is presented, and metabolic data on respiration rates, respiratory control ratios, and ADP:O ratios using various substrates are given. 3. The effects of inhibitors of respiration and ATPase activity and of uncouplers of oxidative phosphorylation are presented. 4. Cytochrome content of the mitochondria as determined from difference spectra is given. No indication of the large amounts of the b type pigment reported in Turbatrix aceti was found. 5. The metabolism and respiratory chain of C. elegans appear to be similar to the classic mammalian systems. The only gross difference noted was the absence of ATPase stimulation by traditional uncouplers of oxidative phosphorylation. In this respect, the C. elegans mitochondria resemble more closely those of Ascaris. ------------------- Key: 252 Medline: 79025333 Authors: Nelson GA;Lew KK;Ward S Title: Intersex, a temperature-sensitive mutant of the nematode C. elegans. Citation: Developmental Biology 66: 386-409 1978 Type: ARTICLE Genes: fem-1 Abstract: A temperature-sensitive mutation, isx-1(hc17), is reported in the nematode Caenorhabditis elegans which alters the sexual phenotypes of both genotypic sexes. At the restrictive temperature, XX animals are functionally female rather than hermaphroditic due to the absence of spermatogenesis, and XO animals develop as intersexes. These intersexes have normal male head and tail structures and exhibit some mating behavior, but possess hermaphrodite-like gonads which produce no sperm and usually contain a few oocytes. An abortive vulva is usually present and evidence is presented which suggests that the formation of the vulva by the hypodermis is induced by the underlying gonad. The direct effects of the mutation are confined to the descendants of four primordial gonad cells. Gametogenesis and gonad sheath development do not seem to be tightly coupled and are shown to differ in their responses to X-chromosome dosage. The interaction of the intersex mutation with mutant alleles of two transformer genes tra-1 and tra-2 is discussed and a model for the action of these genes in gonad development and sex determination is proposed. ------------------- Key: 253 Medline: 78036192 Authors: Neuschulz N Title: Axenic culture of free living nematodes a literature Citation: Zeitschrift fur Versuchstierkunde 19: 241-247 1977 Type: REVIEW Genes: Abstract: In German. ------------------- Key: 254 Medline: Authors: Nicholas WL Title: The cultural and nutritional requirements of free-living nematodes of the genus Rhabditis and related genera. Citation: Technical Bulletin Min. Agric. London 7: 161-168 1959 Type: REVIEW Genes: Abstract: ------------------- Key: 255 Medline: Authors: Nicholas WL Title: The biology of free-living nematodes. Citation: Clarendon Press, Oxford : 1-219 1975 Type: MONOGR Genes: Abstract: ------------------- Key: 256 Medline: Authors: Neuschulz N Title: Axenische Kultivierung freilebender Nematoden. Citation: Wissenschaftliche Zeitschrift der Ernst-Moritz . . . 26: 87-102 1977 Type: ARTICLE Genes: Abstract: The nutritive substratum for axenic nematode cultivation consists of a chemically known basal media and a small supplement of cell or tissue extract. The latter contains an essential growth factor, which has been substituted only recently by sterols, heme and various proteins or glycogen as heme adsorbent. As the population growth in chemically defined media is still insufficient, further research is necessary to clear up the nature of the growth factor. For non-nutritive investigations peptone-yeast-liver-media and other extract mixtures are suitable. Besides giving new research results the present paper contains an historical outline and discusses some points of interest for the selection of test animals. By a detailed description of axenization, inoculation and supplement preparation the paper will also be of use as the first instruction for axenic cultivation of free-living nematodes written in German. ------------------- Key: 257 Medline: Authors: Nicholas WL;Dougherty EC;Hansen EL Title: Axenic cultivation of C. briggsae (Nematoda: Rhabditidae) with chemically undefined supplements; comparative studies with related nematodes. Citation: Annals of the New York Academy of Sciences 77: 218-236 1959 Type: REVIEW Genes: Abstract: This paper is addressed primarily to the unsolved problems of culturing Caenorhabditis briggsae axenically. Included also are some comparative studies of related rhabditid nematodes. ------------------- Key: 258 Medline: Authors: Nicholas WL;Dougherty EC;Hansen EL;Holm-Hansen O;Moses V Title: The incorporation of 14C from sodium acetate-2-14C into the amino acids of the soil-inhabiting nematode, Caenorhabditis briggsae. Citation: Journal of Experimental Biology 37: 435-443 1960 Type: ARTICLE Genes: Abstract: 1. The nematode, Caenorhabditis briggsae, was cultured axenically in a mixture of chick embryo extract, autoclaved liver extract and sodium acetate-2-14C. A protein hydrolysate was prepared from the worms and the eggs which were collected from the cultures. 2. Chromatography and radioautography were carried out in a study of the amino acid composition of the hydrolysate. The following amino acids were found labelled: aspartic acid, glutamic acid, alanine, proline, glycine, serine. Cystein and cystine were oxidized to cysteic acid which was also labelled. The following amino acids were not labelled: arginine, histidine, lysine, methionine, threonine, tyrosine, valine and the combined spot representing phenylalanine, leucine and isoleucine. Tryptophane would have been destroyed by our method of hydrolysis. 3. Since the labelled amino acids are synthesized by the worm, it is suggested, tentatively, that they are not required in an otherwise adequate diet. So far as the unlabelled amino acids are concerned, it is suggested, on the basis of the results of certain culture experiments (published separately) that, with the probable exception of tyrosine, they are essential in the diet of C. briggsae. ------------------- Key: 259 Medline: Authors: Nicholas WL;Grassia A;Viswanathan S Title: The efficiency with which C. briggsae (Rhabditidae) feeds on the bacterium, Escherichia coli. Citation: Nematologica 19: 411-420 1973 Type: ARTICLE Genes: Abstract: The rate of removal of the bacterium E. coli from aqueous suspensions by C. briggsae in feeding has been studied. The decrease in bacteria with time follows a negative exponential equation when bacterial multiplication was restricted and nematode growth was minimal. It was inferred that the feeding activity of the nematodes is maintained at a constant level over a wide range of bacterial concentrations. Other experiments supported the contention that C. briggsae requires dense suspensions of bacteria for the maintenance of cultures and gave estimates of the efficiency of conversion of bacterial protoplasm to worm protoplasm. ------------------- Key: 260 Medline: Authors: Nicholas WL;Hansen EL;Dougherty EC Title: The B-Vitamins required by Caenorhabditis briggsae (Rhabditidae). Citation: Nematologica 8: 129-135 1962 Type: ARTICLE Genes: Abstract: To find which of the B vitamins are required by Caenorhabditis briggsae Dougherty & Nigon, it was cultured axenically in a known medium together with chick embryo extract. The concentration of each vitamin added to the medium was varied, and each was omitted in turn. Omitting thiamine, riboflavin, folic acid, calcium pantothenate, niacinamide and pyridoxine was deleterious. ------------------- Key: 261 Medline: Authors: Nicholas WL;Jantunen R Title: A biotin requirement for C. briggsae (Rhabditidae). Citation: Nematologica 9: 332-336 1963 Type: ARTICLE Genes: Abstract: Caenorhabditis briggsae can be cultured axenically in a biotin-free basal medium supplemented with chick embryo extract. The addition of avidin, which is known to combine with biotin, is inhibiting. The effect of avidin is nullified by the addition of excess biotin. It is concluded that biotin is a vitamin required by C. briggsae. ------------------- Key: 262 Medline: Authors: Nicholas WL;Jantunen R Title: C. briggsae (Rhabditidae) under anaerobic conditions. Citation: Nematologica 10: 409-418 1964 Type: ARTICLE Genes: Abstract: The effect of anaerobic conditions on the eggs, larval stages and adults of C. briggsae was investigated. Anaerobic conditions were produced by exposing the eelworms, in drops of media, to a stream of carefully purified moist N2 or H2. Temperature, the osmotic properties of the media in which the worms were suspended, and pH were considered in designing the experiments. The nematodes were maintained under axenic conditions while anaerobic. It is concluded that swimming is impaired by O2 lack, rapidly leading to complete paralysis. Eelworms recover when returned to aerobic conditions after a short period of paralysis, but after longer periods, of the order of 24 hours, they fail to recover. Eggs survive for several days under anaerobic conditions, but hatching is inhibited until conditions become aerobic. ------------------- Key: 263 Medline: Authors: Nicholas WL;Jantunen R Title: The effect of different concentrations of oxygen and of carbon dioxide on the growth and reproduction of C. briggsae (Rhabditidae). Citation: Nematologica 12: 328-336 1966 Type: ARTICLE Genes: Abstract: The effect of different partial pressures of oxygen on the survival, growth and reproduction of Caenorhabditis briggsae was investigated under axenic conditions. Small volumes of culture medium were inoculated with young larvae, equilibrated with mixtures of oxygen and nitrogen and of oxygen, nitrogen and carbon dioxide, and the development of the cultures followed under the microscope. It was concluded that growth was progressively retarded as the partial pressure of oxygen was reduced below 30 mm Hg and stopped at low levels (below about 1.2 mm HG). The addition of carbon dioxide to the gas mixture probably retarded growth slightly. ------------------- Key: 264 Medline: Authors: Nicholas WL;McEntegart MG Title: A technique for obtaining axenic cultures of rhabditid nematodes. Citation: Journal of Helminthology 31: 135-144 1957 Type: ARTICLE Genes: Abstract: The ultimate purpose of our experiments is to study the nutritional and cultural requirements of free-living nematodes. Before this can be achieved it is essential to develop methods by which the nematodes can be cultured in media free from other organisms, i.e. axenically. Dougherty and Calhoun have reviewed the earlier literature on attempts to obtain axenic cultures of nematodes, and they have developed a method of rendering several species of Rhabditinae axenic. Dougherty and his co-workers have shown that, starting with worms which have been axenized by this method, the growth and reproduction of one species, Caenorhabditis briggsae (=Rhabditis briggsae), can be maintained satisfactorily by subculture in axenic media. However, this method of axenizing the worms is apparently not always equally satisfactory for axenizing other species of Rhabditinae and we have found that it frequently gives unsatisfactory results with the three species which we have worked, see below. ------------------- Key: 265 Medline: Authors: Nicholas WL;Stewart AC Title: The calorific value of C. elegans (Rhabditidae). Citation: Nematologica 24: 45-50 1978 Type: ARTICLE Genes: Abstract: The calorific value of populations of Caenorhabditis elegans was measured by bomb-calorimetry. A value of 27.59 kJ per g ash-free dry weight was obtained (=6,316 calories per g). This value is high, but agrees well with calculations based on previously published analyses of lipid and glycogen reserves in Caenorhabditis sp. It is suggested that when harvested from a rich culture of bacteria Caenorhabditis has substantial lipid reserves accounting for its high calorific value. ------------------- Key: 266 Medline: Authors: Nicholas WL;Viswanathan S Title: A study of the nutrition of C. briggsae (Rhabditidae) fed on Carbon-14 and Phosphorus-32 labelled bacteria. Citation: Nematologica 21: 385-400 1975 Type: ARTICLE Genes: Abstract: Cultures of Caenorhabditis briggsae were fed on Escherichia coli pre-labelled with 14C or 32P. Budgets were constructed to show what proportions of the digested 14C or 32P were retained by the nematode, excreted and, with 14C, respired. A substantial part of the digested C and P appear as soluble metabolites in the medium. Data are also presented on the distribution of 14C and 32P in major tissue fractions of the nematode, and on the rate of loss of radioactivity from nematodes in culture. The percentage of 14C from digested E. coli retained within the nematodes' tissue varied with the substrate used to label E. coli from 17% to 51%. It is suggested that the percentage retained when feeding on E. coli labelled with {14D]NaHCO3, about 20%, in the experiments reported may be a useful criterion in studies of the ecological energetics of baceria-feeding ------------------- Key: 267 Medline: Authors: Nickle WR;Ayre GL Title: C. dolichura in the head glands of the ants Camponotus herculeanus (L.) and Acanthomyops claviger (Roger) in Ontario/ Citation: Proceedings of the Entomological Society of Ontario 96: 96-98 1966 Type: ARTICLE Genes: Abstract: ------------------- Key: 269 Medline: Authors: Nigon V Title: Le determinisme du sexe chez un Nematode libre hermaphrodite Rhabditis dolichura Schneider. Citation: Bulletin de la Societe Zoologique de France 71: 78-86 1947 Type: ARTICLE Genes: Abstract: ------------------- Key: 270 Medline: Authors: Nigon V Title: Effects de la polyploidie chez un nematode libre. Citation: C.R. des Seances de l'Academie des Sciences Serie D 228: 1161-1162 1949 Type: ARTICLE Genes: Abstract: In French. ------------------- Key: 271 Medline: Authors: Nigon V Title: Les modalites de la reproduction et le determinisme du sexe chez quelques nematodes libres. Citation: Annales de Sciences Naturelles - Zool. Biol. Anim. 11: 1-132 1949 Type: ARTICLE Genes: Abstract: ------------------- Key: 272 Medline: Authors: Nigon V Title: Contributions a la critique experimentale des theories de la continuite germinale et de la lignee pure. Citation: Acta Biologica Academiae Scientiarum Hungaricae 5: 96-117 1954 Type: ARTICLE Genes: Abstract: In French. ------------------- Key: 273 Medline: Authors: Nigon V Title: Developpement et reproduction des nematodes. Citation: "Traite de Zoologie, Tome IV." Grasse PP (ed), Masson et Cie, Paris, France. : 218-294 1965 Type: REVIEW Genes: Abstract: In French. ------------------- Key: 274 Medline: Authors: Nigon V;Arcel R Title: Effets d'une elevation de temperature sur la prophase meiotique d'un nematode libre. Citation: C.R. des Seances de l'Academie des Sciences Serie D 232: 1032-1034 1951 Type: ARTICLE Genes: Abstract: In French. ------------------- Key: 275 Medline: Authors: Nigon V;Brun J Title: L'evolution des structures nucleaires dans l'ovogenese de C. elegans Maupas 1900. Citation: Chromosoma 7: 129-169 1955 Type: ARTICLE Genes: Abstract: In French. ------------------- Key: 276 Medline: 68040168 Authors: Nigon V;Brun J Title: Genetique et evolution des nematodes libres. Perspectives tirees de l'etude de C. elegans. Citation: Experientia 23: 161-170 1967 Type: REVIEW Genes: Abstract: Free-living nematodes are endowed with a set of properties that make them specially attractive for experimental work. Geneticists and evolutionists may be especially interested in their easy cultivation, great fecundity and polymorphism. As an example, some results are brought concerning Caenorhabditis elegans and related species: (1) Sex determination occurs as the expression of a genic balance involving differences in the number of chromosomes. The alternatives gynogenesis, amphimixis, or auto-heterofecundation take a prominant place in the reproduction processes of these species. (2) Polyploidy may be obtained by heat-shock, giving rise to individuals showing characteristic chromosomal unbalance and variability. (3) C. elegans, which cannot normally be raised at a higher temperature than 22C, has been gradually adapted to temperatures up to 24.5C. This acclimatization implies an adaptive transformation of the ovarian physiology; this effect is obtained after long training, taking more than 1000 generations. Study of the process of acclimatization shows that its genetical basis may be partly of a non-genic nature, partly of a genic type. Hypotheses are developed for explaining this phenomenon and for the understanding of the evolution from free-living to parasitic nematodes. ------------------- Key: 277 Medline: Authors: Nigon V;Dougherty EC Title: Reproduct patterns and attempts at reciprocal crossing of Rhabditis elegans Maupas, 1900, and Rhabditis briggsae Dougherty & Nigon, 1949 (Nematoda: Rhabditidae). Citation: Journal of Experimental Zoology 112: 485-503 1949 Type: ARTICLE Genes: Abstract: For a long time the definition of a species has been the subject of numerous controversies related to the relative weighting that should be accorded to a number of criteria-morphological, ecological, and genetic-that today serve as a guide in the separation of related species. Morphological criteria, the importance of which is evident at the outset, involve, however, some refinement of application in the case of animals in which the anatomy offers only a limited number of possible variations. This is particularly the case with free-living nematodes belonging to the genus Rhabditis, in which the over 100 species named up to the present are differentiated largely on the basis of minimal characters. It was for this reason that early in the 1900's, Maupas ('18), tried to test species differences by attempts at hybridization. Among the experiments performed, several involved hermaphroditic species...... ------------------- Key: 278 Medline: Authors: Nigon V;Dougherty EC Title: A dwarf mutation in a nematode. A morphological mutant of Rhabditis briggsae, a free-living soil nematode. Citation: Journal of Heredity 41: 103-109 1950 Type: ARTICLE Genes: Abstract: 1. A morphological mutant of the self-fertilizing, hermaphroditic, free-living nematode species Rhabditis briggsae Dougherty and Nigon, 1949, is described in detail-the first to be reported in the phylum Nematoda. 2. It is designated micro and affects the gross appearance of the homozygous individuals by a general reduction in size, impairment of the egg-laying mechanism so that the ova are laid so slowly that they accumulate and kill the hermaphroditic parent, and alteration in the structure of the male copulatory bursa. 3. The mutation appeared after heat treatment among descendants of one of a series of isolated hermaphrodites kept at a temperature of 25C for 18 hours during the time of sexual maturation. It is not yet possible to state whether or not a causal mechanism between heat and mutation may exist in these forms. The inheritance of the micro gene is shown to follow a single-factor pattern and to be recessive and not sex-linked. 4. Experiments are described in which micro hermaphrodites have been successfully outcrossed with wild type males. The self-fertilized progeny of the micro parent can be readily distinguished from the cross-fertilized hybrid progeny by the mutant phenotype of the former vs. the wild phenotype of the latter. 5. The theoretical consequences of the production of this mutant are discussed in relation to the general taxonomy of the group, to the phenomenon of eutely (cell-constancy), to the practical usefulness of the micro gene as a chromosome marker and a test of cross-fertilization in linkage and other genetic experiments, and to the general potential importance of free-living nematodes in genetic research. ------------------- Key: 280 Medline: Authors: Nigon V;Guerrier P;Monin H Title: L'Architecture polaire de l'oeuf et les movements des constituants cellulaires au cour des premieres etapes du developpement chez quelques nematodes. Citation: Bulletin Biologique de la France et de la Belgique 94: 132-201 1960 Type: ARTICLE Genes: Abstract: In French. ------------------- Key: 281 Medline: Authors: Nolan RA Title: Asteromyces cruciatus from North America. Citation: Mycologia 64: 430-433 1972 Type: ARTICLE Genes: Abstract: The hyphomycete Asteromyces cruciatus F. & Mme Moreau was described without a Latin diagnosis or a designated type. The taxon was validated by Hennebert. The known distribution of this monotypic genus has been limited. F. and Mme Moreau found the fungus in sand dunes at Point du Siege (under Psamma sp.) and between Franceville and Le Home (under Agropyrum sp.) on the Normandy coast of France. Brown found A. cruciatus in open sand in the intertidal zone at Studland, Dorset and Sandwich, Kent, England; and Nicot found it in sand dunes and beach samples at Malo-les-Bains on the North Sea coast of France. ------------------- Key: 282 Medline: Authors: Nonnemacher-Godet J;Dougherty EC Title: Incorporation of tritiated thymidine in the cells of C. briggsae (Nematoda) reared in axenic culture. Citation: Journal of Cell Biology 22: 281-290 1964 Type: ARTICLE Genes: Abstract: In the rhabditid nematode Caenorhabditis briggsae the incorporation of thymidine-H3 has been studied by autoradiography after Feulgen staining, with animals maintained under axenic conditions in a medium of only partly defined composition. Labeling has been followed in adults left in the presence of thymidine-H3 for periods of from 1/2 to 24 hours, as well as in adults reared from larvae in the presence of the tritiated nucleoside. A massive incorporation is found in the nuclei of the gonads and intestine; also a less intense particulate cytoplasmic incorporation is clear in certain cells, especially those of the intestine. In general, all labeling has proved to be sensitive to DNase, but resistant to RNase. The label's stability has been tested by the transfer of adults into a medium containing "cold" thymidine. They remain there for up to 48 hours. A transfer for 24 hours results in a considerable decrease in the intensity of nuclear and cytoplasmic labeling; a stay of 48 hours leads to its complete disappearance from non-dividing (intestinal) as well as dividing (gonadal) nuclei. A phenomenon of DNA turnover is envisaged and discussed as a possible physiological attribute of C. briggsae. ------------------- Key: 283 Medline: 75151562 Authors: O'Farrell PH Title: High-resolution two-dimensional electrophoresis of Citation: Journal of Biological Chemistry 250: 4007-4021 1975 Type: ARTICLE Genes: Abstract: A technique has been developed for the separation of proteins by two-dimensional polyacrylamide gel electrophoresis. Due to its resolution and sensitivity, this technique is a powerful tool for the analysis and detection of proteins from complex biological sources. Proteins are separated according to isoelectric point by isoelectric focusing in the first dimension, and according to molecular weight by sodium dodecyl sulfate electrophoresis in the second dimension. Since these two parameters are unrelated, it is possible to obtain an almost uniform distribution of protein spots across a two-dimensional gel. This technique has resolved 1100 different components from Escherichia coli and should be capable of resolving a maximum of 5000 proteins. A protein containing as little as one disintegration per min of either 14C or 35S can be detected by autoradiography. A protein which constitutes 10-4 to 10-5% of the total protein can be detected and quantified by autoradiography. The reproducibility of the separation is sufficient to permit each spot on one separation to be matched with a spot on a different separation. This technique provides a method for estimation (at the described sensitivities) of the number of proteins made by any biological system. This system can resolve proteins differing in a single charge and consequently can be used in the analysis of in vivo modifications resulting in a change in charge. Proteins whose charge is changed by missense mutations can be identified. A detailed description of the methods as well as the characteristics of this system are presented. ------------------- Key: 284 Medline: Authors: Osche G Title: Systematik und phylogenie der gattung Rhabditis (Nematoda). Citation: Zoologische Jahrbucher - Abteilung Fur Allgemeine Zoologie Und Physiologie Der Tiere 81: 190-280 1952 Type: ARTICLE Genes: Abstract: ------------------- Key: 287 Medline: Authors: Ouazana R Title: A morphological temperature-sensitive mutant of the nematode C. elegans var. Bergerac. Citation: Experientia 34: 170-171 1978 Type: ARTICLE Genes: Abstract: A morphological temperature-sensitive mutant of Caenorhabditis elegans displays 2 overlapping temperature-sensitive periods, both occurring during the post-embryonic development. Data prove that these 2 phenotypes are controlled by the same locus and are not inherited as maternal factors. ------------------- Key: 288 Medline: 75207685 Authors: Ouazana R;Brun JL Title: Intracistronic recombination at a dwarfing locus in the free living self fertilizing nematode C. elegans. Citation: C.R. des Seances de l'Academie des Sciences Serie D 280: 1895-1898 1975 Type: REVIEW Genes: Abstract: In French. ------------------- Key: 289 Medline: Authors: Ouazana R;Brun J Title: Effect of dumpiness on the development and functioning of eutelic and noneutelic organs in the nematode C. elegans. Citation: Genetica 49: 45-52 1978 Type: ARTICLE Genes: Abstract: We analyze, in the wild-type strain of the Bergerac variety of Caenorhabditis elegans and in eight dumpy mutations distributed among the genome, the morphological and physiological characteristics of two organogenetically different organs: -the intestine, a typically eutelic organ (i.e. an organ whose cell number and disposition are theoretically constant), -the ovotestis, a non-eutelic organ. The ovotestis of all mutants can be distinguished from the wild-type by: -reduced fecundity and productivity, -a different distribution for adult progeny according to daily laying, -slowing of gonadic organogenesis during post-embryonic development. Mutants bearing alleles of the same locus (dpy-e) are similar in their gonad development and function, but mutants at other loci may differ in this respect. Several hypotheses concerning the relationship between ovotestis development and function are discussed. As the male phase of its hermaphroditic gonad does not seem to be affected in dumpy mutants, the observed slowing would mainly affect oocyte multiplication and differentiation. We show that intestinal development is independent of dumpiness which does not affect either the number or the positional ------------------- Key: 290 Medline: Authors: Ouazana R;Gibert M-A Title: Cuticular collagen composition of the nematode C. elegans, Bergerac wild-type strain. Citation: C.R. des Seances de l'Academie des Sciences Serie D 288: 911-914 1979 Type: ARTICLE Genes: Abstract: We describe a technique allowing us to isolate the cuticles of Caenorhabditis elegans. The good condition of purification is verified by Electron Microscopy. The amino acid composition of the cuticular collagen, compared with that of Ascaris lumbricoides, shows two important differences only: the first one is the ratio hydroxyproline/proline which is 0,47 for C. elegans but only 0,065 for A. lumbricoides; the second one is the alanine which is near by twice as much for C. elegans. ------------------- Key: 291 Medline: 72135442 Authors: Ozerol NH;Silverman PH Title: Exsheathment phenomenon in the infective-stage larvae of Haemonchus contortus. Citation: Journal of Parasitology 58: 34-44 1972 Type: ARTICLE Genes: Abstract: The nature of exsheathment of 3rd-stage larvae of Haemonchus contortus was investigated further using a new simplified technique for the study of cuticular ring formation. The presence of a second ring on the 2nd-stage larval cuticle, 8 to 9 u from the anterior, is described. Exsheathing activity was observed to occur in 4 consecutive steps on isolated sheaths of H. contortus. Metabolic fluid and somatic extract of Ascaris suum and Caenorhabditis briggsae were investigated for their ability to stimulate exsheathment in H. contortus. Scanning electron microscopy revealed some aspects of the fine structure of cuticle. Exsheathing factor(s) was found to be thermostable, to require no metal ion activation, and to be active over a broad range of pH. Temperature appeared to be an important factor for the exsheathment activity. ------------------- Key: 292 Medline: 76251418 Authors: Pak WL;Pinto LH Title: Genetic approach to the study of the nervous system. Citation: Annual Review of Biophysics & Bioengineering 5: 397-448 Type: REVIEW Genes: Abstract: Beadle & Tatum first showed that single step mutants may be used to elucidate complex physiological processes other than the mechanism of inheritance. These workers used mutants to analyze the biochemical pathways of the fungus Neurospora. It has long been realized that mutants may also be helpful in the study of the nervous system. However, the early approaches relied on spontaneously occurring mutations or on behavioral changes brought about by selective breeding. Benzer proposed that, instead, single step mutations should be induced and appropriate mutants should be screened for use in the study of the nervous system. In the past few years, the technique of induced mutation has been gaining acceptance as potentially one of the most powerful tools available to ------------------- Key: 294 Medline: 76182459 Authors: Patel TR;McFadden BA Title: A simple spectrophotometric method for measurement of nematode populations. Citation: Analytical Biochemistry 70: 447-453 1976 Type: ARTICLE Genes: Abstract: An ordinary spectrophotometer was used to study growth rates and increases in population size of nematodes by optical density measurements of nematodes suspended in 30-40% sucrose (w/v) solutions. The sucrose solution retarded the movement of nematodes in suspension and thereby decreased the fluctuations normally observed in optical density. This method was effectively used to study growth rates and increases in population numbers of a free-living nematode, Caenorhabditis elegans. This procedure was also used to quantitate Ascaris lumbricoides eggs in a given sample. The limitations of this method when employed for establishing total nematode counts in a growing culture by direct spectrophotometric readings are ------------------- Key: 295 Medline: 78018746 Authors: Patel TR;McFadden BA Title: Particulate isocitrate lyase and malate synthase in C. elegans. Citation: Archives of Biochemistry & Biophysics 183: 24-30 1977 Type: ARTICLE Genes: Abstract: Biochemical evidence is presented suggesting the particulate nature of some of the glyoxylate cycle enzymes in the free-living nematode Caenorhabditis elegans. A crude homogenate of freshly grown nematodes was prepared by gentle grinding. Isopycnic sucrose gradient centrifugation of the supernatant fraction obtained by low-speed centrifugation yielded four protein bands. The glyoxylate cycle enzymes, isocitrate lyase and malate synthase, appeared in the lowermost band at a density of 1.25 g/cm3, while the mitochondrial enzymes, fumarase and NADH oxidase, equilibrated at a density of 1.18 g/cm3. The glyoxylate cycle and the mitochondrial enzymes were released differentially from the particulate fraction either by sonic treatment or by treatment with 0.1% Triton X-100. The specific activities of isocitrate lyase and malate synthase in the supernatant fraction obtained after a sonic treatment of the particulate fraction were always higher than those observed in the parent fraction. ------------------- Key: 296 Medline: Authors: Patel TR;McFadden BA Title: Axenic and synchronous cultures of C. elegans. Citation: Nematologica 24: 51-62 1978 Type: ARTICLE Genes: Abstract: A technique to axenize cultures of Caenorhabditis elegans on a large scale is described. This procedure has enabled the isolation of eggs of C. elegans in quantities sufficient to perform biochemical tests. Adults from monoxenic cultures were used to isolate eggs. When egg-bearing worms were suspended for 2-3 hr at 25C n an alkaline (0.4 M) solution of NaOH, the worm cuticle was partially digested, releasing free eggs. The high alkalinity rendered the eggs bacteria-free. Eggs were then isolated from a linear sucrose gradient. Eggs from the least dense band (1.13 g/cm3) hatched within 10-13 hr when resuspended in a liquid medium and yielded a synchronous culture. The hatchability of these eggs ranged from 20-35%. Inhibitory effects of 5-fluorodeoxyuridine and hydroxyurea on freshly hatched (L1 stage) worms are described. Levels of isocitrate lyase were determined in ------------------- Key: 297 Medline: 78107010 Authors: Patel TR;McFadden BA Title: C. elegans and Ascaris suum: Fragmentation of isocitrate lyase in crude extracts. Citation: Experimental Parasitology 44: 72-81 1978 Type: ARTICLE Genes: unc-13 Abstract: It is well known that proteolysis often occurs after rupture of metazoan cells. Thus proteins isolated from extracts may not be representative of their native cellular counterparts. In the present research, extensive proteolysis was observed in crude extracts of the free-living soil nematode Caenorhabditis elegans and the parasitic nematode Ascaris suum. Phenylmethylsulfonyl fluoride (PMSF) reduced the loss in activity of isocitrate lyase (EC 4.1.3.1), fumarase (EC 4.2.1.2), and citrate synthase (EC 4.1.3.7) in extracts of C. elegans but had little or no effect upon loss of malate synthase (EC 4.1.3.2). Catalase (EC 1.11.1.6) was stable. The loss of isocitrate lyase and citrate synthase was less pronounced in extracts of 22-day-old embryos of A. suum. Catalase decayed in these extracts. The addition of PMSF reduced the loss in all three of these activities. Fumarase was stable. The number of active fragments of isocitrate lyase recovered after filtration on Sephadex G-200 increased with the length of storage of crude extracts in the absence of PMSF at 4C. Even in the presence of PMSF five activity peaks were observed after storage of extracts of C. elegans at 4C for 72 hr. The molecular weights of active species ranged between 549,000 and 128,000 for isocitrate lyase in extracts of either C. elegans or A. suum. The 549,000- and 214,000-dalton species of isocitrate lyase from A. suum were much more labile at 50C than the 543,000- and ------------------- Key: 298 Medline: 78190959 Authors: Patel TR;McFadden BA Title: C. elegans and Ascaris suum: Inhibition of isocitrate lyase by itaconate. Citation: Experimental Parasitology 44: 262-268 1978 Type: ARTICLE Genes: Abstract: The largest forms of isocitrate lyase from Caenorhabditis elegans and Ascaris suum of 543,000 and 549,000 daltons, respectively, can be purified from three- to five-fold in excellent yield by pelleting from extracts at 160,000g for 4 hr. Isocitrate lyase in the pellet is much more stable toward proteolysis. Itaconate which both inhibits isocitrate lyase and suppresses the level of this enzyme in bacteria inhibits the partially purified isocitrate lyase from both C. elegans and A. suum. The inhibition is noncompetitive with respect to D(s)-isocitrate at one itaconate concentration. The Ki values at 30C, pH 7.7, are 19 and 7.3 uM for the enzyme from C. elegans and A. suum, respectively. Itaconate inhibits the growth of C. elegans in random axenic as well as monoxenic cultures. At a concentration of 10 mM, itaconate is more effective in the inhibition of random axenic cultures than is oxalate, maleate, or succinate. At 60 mM itaconate, reproduction of C. elegans larvae is completely abolished. ------------------- Key: 299 Medline: Authors: Pertel R Title: Axenic cultivation of two species of rhabditid nematodes on a commercial medium. Citation: Nematologica 10: 343-343 1964 Type: ARTICLE Genes: Abstract: A commercially available crude liver medium capable of supporting the axenic cultivation of Caenorhabditis briggsae and Caenorhabditis elegans has been found. It is Bacto-Liver (manufactured by Difco Laboratories Incorporated) - a desiccated and powdered form of fresh liver that has been found to sustain the growth and reproduction of these species. The medium is prepared by Seitz-filtering a 10% suspension of the powdered liver. ------------------- Key: 302 Medline: 76187597 Authors: Pertel R;Paran N;Mattern CFT Title: C. elegans: Localization of cholinesterase associated with anterior nematode structures. Citation: Experimental Parasitology 39: 401-414 1976 Type: ARTICLE Genes: Abstract: By employing a histochemical procedure on adult nematodes, the base of the Caenorhabditis elegans amphid appears to contain acetylcholinesterase and a nonspecific cholinesterase. Some precipitation was observed in the kinetosome region of the inner labial papilla with acethylthiocholine (AtCh) as substrate but not, in limited observations, in the absence of substrate or with butyrylthiocholine (BtCh). The amphidial tips, the tips of the inner labial papillae, and the lining of the buccal cavity contained substantial reaction product at the ultrastructural level, with or without substrates and inhibitors and therefore cannot be related to the presence of a cholinesterase. ------------------- Key: 303 Medline: 75148966 Authors: Pertel R;Wilson SH Title: Histamine content of the nematode, C. elegans. Citation: Comparative & General Pharmacology 5: 83-85 1974 Type: ARTICLE Genes: Abstract: 1. The histamine contect in axenically grown nematodes was found to be 350 ng. per g. wet weight. 2. Histamine content was determined in extracts from the free-living nematode, Caenorhabditis elegans var. Bristol (strain B1-Pl) by an isotope dilution procedure which obviated error encountered in a conventional fluorescence assay. 3. This is the first report of histamine in the Nematoda. ------------------- Key: 305 Medline: Authors: Pinnock CB;Hieb WF;Stokstad ELR Title: A mass culture bioassay method for C. briggsae using population growth rate as a response parameter. Citation: Nematologica 21: 1-4 1975 Type: ARTICLE Genes: Abstract: A bioassay method for C. briggsae using population growth rate as a response parameter is described in which the nematodes are rotated at 1.0 rpm in 5.0 ml medium in 18 mm tubes on a tissue culture rotator. This method permits higher peak populations of nematodes than a previous mass culture method and also allows nephelometric monitoring of population growth. Population growth rate during the initial phase of growth is an effective index of growth and avoids the variations due to inoculum size and accumulation of metabolites associated with use of direct population counts at fixed time intervals. ------------------- Key: 306 Medline: 75158496 Authors: Pinnock C;Shane B;Stokstad ELR Title: Stimulatory effects of peptides on growth of the free-living nematode C. briggsae. Citation: Proc. Society for Experimental Biology & Medicine 148: 710-713 1975 Type: ARTICLE Genes: Abstract: Recent work on ageing and genetics of higher organisms using nematodes as model systems has focused attention on the need for completely defined axenic culture media for these organsisms. The free-living nematode Caenorhabditis briggsae requires the addition of a proteinaceous factor to a medium containing amino acids, vitamins, minerals, nucleotides, heme and a sterol. Proteins from widely different sources have been found to be active. A recent paper has proposed that such proteins derive their sole activity from facilitation of uptake of the essential nutrient heme, possibly by stimulation of phagocytosis. This theory is supported by the activating effect of precipitation on proteins and on heme itself. The evidence presented, however, has not been supported by experimental work in our own laboratory and we feel alternative modes of action of protein growth factors should be considered. The possibility that such factors may derive their activity from peptide fragments produced by gut hydrolysis was investigated and evidence for this is presented here. Peptides are already known to be of considerable importance in the nutrition of bacteria and mammals, however this is the first indication that they may play a role in the nutrition of invertebrate metazoa. ------------------- Key: 307 Medline: Authors: Pinnock CB;Stokstad ELR Title: The effect of heme source on growth of C. briggsae in peptide and carbohydrate supplemented chemically defined medium. Citation: Nematologica 21: 258-260 1975 Type: ARTICLE Genes: Abstract: A recent paper described the stimulatory effects of mixtures of peptides on population growth of C. briggsae in C. briggsae Maintenance Medium (CbMM) supplemented with B-sitosterol and cytochrome C. We describe here preliminary evidence that the nature of the heme source influences the activity of such supplements, and also that a previously unsuspected class of nutrients, guar gum, can stimulate growth. ------------------- Key: 310 Medline: 79001394 Authors: Popham JD;Webster JM Title: An alternative interpretation of the fine structure of the basal zone of the cuticle of the dauerlarva of the nematode C. elegans (Nematoda). Citation: Canadian Journal of Zoology 56: 1556-1563 1978 Type: ARTICLE Genes: Abstract: The fine structure of the basal zone of the cuticle of the dauerlarva of Caenorhabditis elegans was examined in order to help resolve controversies regarding its structure. The results show that the striated layer in the basal zone consists of two sets of laminae oriented at right angles to each other. One set of laminae consists of longitudinally oriented, alternately thick and thin, osmiophilic strips with the distance between similar strips measuring 19 nm. The other set of laminae consists only of thick strips spaced about 14.5 nm apart which are oriented circumferentially about the larva. It is speculated that the striated layer of the basal zone of the cuticle consists of blocks of protein separated by this apparent network of interconnecting osmiophilic laminae. ------------------- Key: 311 Medline: Authors: Popham JD;Webster JM Title: Aspects of the fine structure of the dauer larva of the nematode C. elegans. Citation: Canadian Journal of Zoology 57: 794-800 1979 Type: ARTICLE Genes: Abstract: Examination of the ultrastructure of the dauer larva of Caenorhabditis elegans showed that cells in the lateral cord and body wall muscle had irregular profiles, few Golgi bodies, and cisternae of endoplasmic reticulum, but they contained abundant lipid and glycogen. These cells and the esophageal cells had mitochondria in the condensed conformation. The intestinal lumen was small and the brush border was so compact that individual microvilli were difficult to discern. Intestinal cells had cytosomes with irregular profiles and unhomogeneous matrices. The striated layer was absent from the cuticle covering the lips and papillae. These ultrastructural features are correlated with the dauer larva's low metabolic rate, its resistance to toxic chemicals and to adverse environmental conditions, and its ability to detect food and to feed soon after exposure to a hospitable environment. ------------------- Key: 312 Medline: Authors: Popham JD;Webster JM Title: The use of osmium mixtures in localizing ions in C. Citation: Nematologica 25: 67-75 1979 Type: ARTICLE Genes: Abstract: Electron microscopy of Caenorhabditis elegans fixed in an aqueous solution of osmium tetroxide mixed with potassium pyroantimonate, silver lactate or lead nitrate revealed the following. Calcium is localised in the median and basal layers of the cuticle, in the myofibrils of the body wall muscle, in mitochondria, and in intestinal cytosomes. Chloride ions are localised in the cortical zone of the cuticle along the apical membrane infoldings of the hypodermal cells and in the ground substance of the cytoplasm and vesicles of intestinal cells. Orthophosphate ions are localised in nucleoli and heterochromatin, in cytosomes of the intestinal cells, in foldings of the external membranes of the hypodermis, and in the intracristal space of mitochondria. Orthophosphates and/or sulphates surround the microvilli of intestinal cells. The results suggest that chloride ion regulation may occur in the hypodermal cells and intestinal cells rather than in the excretory tubules of C. elegans. ------------------- Key: 313 Medline: Authors: Potts FA Title: Notes on the free-living nematodes I. The hermaphrodite species. Citation: Quarterly Journal of Microscopical Science 55: 433-484 1910 Type: REVIEW Genes: Abstract: Orley divided the Nematoda into three groups, roughly corresponding to differences of habitat found in the phylum. (1) Nematozoa embracing all parasitic forms, (2) Rhabditiformae which live free in "decomposing organic substances or in earth saturated with such substances", and (3) Anguillulidae, the rest of the free-living nematodes, found in soil or water. Such a classification, grounded on ecology, pays no attention to the facts of morphology, and is naturally out of place in zoological arrangement, which aims at expressing the relationship of animals by descent. ------------------- Key: 314 Medline: 79114489 Authors: Quinn WG;Gould JL Title: Nerves and genes. Citation: Nature 278: 19-23 1979 Type: REVIEW Genes: Abstract: It is the business of scientists to explain away the magic in the world. The largest coherent body of magic remaining is the behaviour of men and animals. Behavioural geneticists try to construct plausible explanations for behaviour patterns by studying genetic variants. Historically, they have sought to compare inbred strains, or to cross them and examine the progeny. Such comparisons inevitably involve many genetic differences, making the results virtually impossible to interpret. A more recent approach initiated by Delbruck and Benzer has been to generate single-gene mutations which affect behaviour, to analyse the mutants, and to try to infer general principles about how normal behaviour is created. One advantage of such single-gene changes is that now behavioural patterns can be dissected into their component parts. This genetic extension of traditional ethology should have something important to say about how behaviour is organised and regulated, and has been reviewed recently. A more ambitious and potentially more powerful strategy is to examine the effects of single-gene mutations on the ultimate common denominator of behaviour-the physiology of nerve cells and the wiring patterns of neural circuits. This review traces the recent progress of this approach, selecting the work which seems to offer the best prospects ------------------- Key: 315 Medline: Authors: Rammeloo J Title: Harposporium anguillulae Lohde (moniliales), espece nematophage, trouve en Belgique. Citation: Biologisch Jaarboek 41: 180-182 1973 Type: ARTICLE Genes: Abstract: In French. ------------------- Key: 316 Medline: Authors: Riddle DL Title: A genetic pathway for dauer larva formation in C. elegans. Citation: Stadler Genetics Symposium 9: 101-120 1977 Type: REVIEW Genes: daf-1 daf-2 daf-3 daf-4 daf-6 daf-7 daf-8 daf-9 daf-10 Abstract: C. elegans is a roundworm, a free-living soil nematode. The dauer larva is a non-feeding, non-growing larval stage which is formed under conditions of starvation. It possesses a relatively impermeable cuticle and differs from all other larval stages in behavior and morphology. Dauer larva formation is a "developmental switch" in the life cycle which offers special advantages for genetic study. A partial genetic pathway for dauer larva formation has been established. Genetic characterization of additional mutants should reveal more details of this pathway. One class of mutants already characterized exhibits morphological alterations in sensory neurons, as determined by electron microscopy. Such mutants are useful for the study of nerve morphogenesis. ------------------- Key: 317 Medline: Authors: Riddle DL Title: The genetics of development and behavior in C. elegans. Citation: Journal of Nematology 10: 1-16 1978 Type: REVIEW Genes: sup-3 unc-40 Abstract: The current genetic research on Caenorhabditis elegans and the application of genetic techniques to the analysis of development and behavior in this animal are reviewed. Some aspects of the work are emphasized more than others and this inevitably reflects the author's own interests and prejudices. An effort was made to point out the advantages that C. elegans offers for certain types of investigations and to point out, in general terms, the relevance of this work to other areas of biological research. ------------------- Key: 318 Medline: 78215868 Authors: Riddle DL;Brenner S Title: Indirect suppression in C. elegans. Citation: Genetics 89: 299-314 1978 Type: ARTICLE Genes: sup-3 unc-1 unc-15 unc-24 unc-41 unc-42 unc-52 unc-87 eDf1 Abstract: Two cases of indirect suppression have been characterized. One case involves suppressors compensating for defects in muscle structure. Nine independent suppressor mutations were judged to lie in a single suppressor gene, sup-3. Suppression is dominant, but dose dependent, and results in improved locomotion, as well as in an increase in the ability of mutant animals to lay eggs. Mutations in six genes known to affect muscle structure were tested for suppression by representative sup-3 mutations. Alleles of three of the six genes are suppressed, two of which are known to code for thick filament proteins. One suppressor allele was identified as a deletion by genetic criteria. A second case of indirect suppression is not associated with muscle defects, but involves two mutant genes producing uncoordinated phenotypes very similar to one another. As in the first case, suppression is domiant but dose dependent and is not allele specific. ------------------- Key: 320 Medline: Authors: Rose AM;Baillie DL Title: The effect of temperature and parental age on recombination and nondisjunction in C. elegans. Citation: Genetics 92: 409-418 1979 Type: ARTICLE Genes: dpy-11 unc-68 Abstract: The effect of temperature and parental age on recombination frequency in C. elegans was studied between pairs of closely linked markers on linkage groups I and IV. In the regions studied, recombination frequency varied threefold over the temperature range 13.5C to 26C. Temperature-shift experiments indicated that a temperature-sensitive recombination event occurs approximately 50 oocytes prior to fertilization. Recombination frequency was observed to decrease with maternal age. The greatest decrease was observed in the first 24 hours of egg production. The frequency of male progeny, a measure of X-chromosome nondisjunction was also studied. This frequency increased with elevated temperature and age of the parent. ------------------- Key: 321 Medline: 80032926 Authors: Rose AM;Baillie DL Title: A mutation in C. elegans that increases recombination frequency more then threefold. Citation: Nature 281: 599-600 1979 Type: ARTICLE Genes: dpy-5 dpy-11 dpy-14 rec-1 unc-13 unc-29 unc-42 unc-43 Abstract: In higher organisms the rate of recombination between genetic loci is presumably responsive to selective pressure. Recently, selective pressures and mutational events that influence recombination have been reviewed. Mutational sites and chromosomal rearrangements that enhance or suppress recombination frequency in specific regions are known, but general mechanisms that enhance recombination have not yet been discovered. We describe here the isolation and characterisation of a strain of the hermaphroditic nematode, Caenorhabditis elegans, that has a recombination frequency at least threefold higher than that found in the wild type. In this strain, rec-1, the number of reciprocal recombination events between linked loci is increased. This is true for all pairs of linked loci studies so far. The high recombination strain behaves as if it carries a classical recessive mutation, although a second mutation exists which can alter the recessive ------------------- Key: 323 Medline: Authors: Rothstein M Title: Nematode biochemistry - III. Excretion products. Citation: Comparative Biochemistry & Physiology 9: 51-59 1963 Type: ARTICLE Genes: Abstract: 1. The free-living nematode, Caenorhabditis briggsae, after incubation with various radioactive substrates, excretes nitrogen chiefly in the form of ammonia and amino acids. No significant amounts of urea, uric acid, allantoin or creatinine are produced. 2. Highly radioactive acidic and neutral components are excreted into the incubation media. 3. The results obtained are in general agreement with the known excretion products of a number of parasitic ------------------- Key: 324 Medline: Authors: Rothstein M Title: Nematode biochemistry - V. Intermediary metabolism and amino acid interconversions in C. briggsae. Citation: Comparative Biochemistry & Physiology 14: 541-552 1965 Type: ARTICLE Genes: Abstract: 1. Formate-C14 is readily incorporated into serine by Caenorhabditis briggsae, presumably by a one-carbon addition to glycine. The reverse reaction (conversion of serine to glycine) appears to take place only to a limited degree. The formate-carbon is also incorporated into glutamate, aspartate and alanine. 2. C(14)O(2) is incorporated, as expected, into the amino acids related to the tricarboxylic acid cycle, probably by way of C02 fixation via malic enzyme. A number of unidentified radioactive acids were also formed, suggesting the existence of additional metabolic pathways. 3. Other findings demonstrated the production of glutamine and asparagine in the incubation medium of worms fed acetate-2-C14; the identification of y-aminobutyric acid in the worms; the conversion of phenylalanine to tryosine, and the inability of the worms to form taurine from labeled acetate or methionine. 4. Products found in the incubation medium of C. briggsae depend upon the substrate and show a direct metabolic relationship to the latter. ------------------- Key: 325 Medline: 71030457 Authors: Rothstein M Title: Nematode biochemistry - IX. Lack of sterol biosynthesis in free-living nematodes. Citation: Comparative Biochemistry & Physiology 27: 309-317 1968 Type: ARTICLE Genes: Abstract: 1. Under axenic conditions, the free-living nematodes, Caenorhabditis briggsae, Turbatrix aceti and Panagrellus redivivus, are unable to synthesize cholesterol from acetate-2-C14 or DL-mevalonate-2-C14. 2. No evidence could be found that sterols other than cholesterol are synthesized by any of the organisms. ------------------- Key: 326 Medline: 70054080 Authors: Rothstein M Title: Nematode biochemistry - X. Excretion of glycerol by free-living nematodes. Citation: Comparative Biochemistry & Physiology 30: 641-648 1969 Type: ARTICLE Genes: Abstract: 1. The free-living nematode, Caenorhabditis briggsae, excretes labeled glycerol as a major product when incubated with acetate-14C in "whole medium". 2. When incubated in water of buffer solution, little or no glycerol is formed, glucose and trehalose being the major products. 3. Turbatrix aceti yields similar results. Panagrellus redivivus shows similar behavior when incubated in water, but in "whole medium" other neutral products, presumably sugars, are formed, in addition to glycerol. ------------------- Key: 327 Medline: Authors: Rothstein M Title: Nematode biochemistry XI, biosynthesis of fatty acids by C. briggsae and Panagrellus redivivus. Citation: International Journal of Biochemistry 1: 422-428 1970 Type: ARTICLE Genes: Abstract: 1. The free-living nematodes, Caenorhabditis briggsae and Panagrellus redivivus, are capable of synthesizing polyunsaturated fatty acids de novo. Acetate-2-14C yields labelled linoleic acid (18:2), linolenic acid (18:3), and C20 fatty acids with up to 5 double bonds. Evidence is presented which shows that these acids are labelled throughout the chain and not formed by simple addition of a labelled 2-carbon unit to pre-existing precursors. 2. Stearate-1-14C and oleate-1-14C are also converted directly to polyunsaturated fatty acids in C. briggsae, providing further proof that oleate can be desaturated to linoleate. Of all the multicellular animals studied so far, only free-living nematodes have this biosynthetic capability. ------------------- Key: 328 Medline: 75057195 Authors: Rothstein M Title: Practical methods for the axenic culture of the free-living nematodes Turbatrix aceti and C. briggsae. Citation: Comparative Biochemistry & Physiology 49B: 669-678 1974 Type: ARTICLE Genes: Abstract: 1. Media are described which are suitable for the axenic culture of large numbers of the free-living nematodes, Turbatrix aceti and Caenorhabditis briggsae. 2. T. aceti grows to a population of over 250,000 worms/ml in 18 days at 30C in a defined basal medium to which is added acetic acid (4%), myoglobin or hemoglobin (500 ug/ml) and cholesterol or other sterols (50 ug/ml). For convenience, a mixture of cholesterol, B-sitosterol and ergosterol is used. 3. C. briggsae grows consistently to over 50,000 worms/ml in 8 days at 20C in the same medium, but without the acetic acid and with the replacement of the amino acids by 4% soy-peptone. Cytochrome c can substitute for myoglobin or hemoglobin. ------------------- Key: 330 Medline: 66161633 Authors: Rothstein M;Cook E Title: Nematode biochemistry - VI. Conditions for axenic culture of Turbatrix aceti, Panagrellus redivivus, Rhabditis anomala and C. briggsae. Citation: Comparative Biochemistry & Physiology 17: 683-692 1966 Type: ARTICLE Genes: Abstract: 1. The small, free-living nematodes, Turbatrix aceti, Rhabditis anomala and Panagrellus redivivus, can be readily grown in axenic culture on a scale suitable for biochemical studies. 2. A number of observations related to the growth requirements of the organisms are reported. 3. An improved yield of Caenorhabditis briggsae has been attained by addition of autoclaved casein to the medium, permitting a reduction in the amount of liver extract required. This procedure also appears to be effective for T. aceti. ------------------- Key: 331 Medline: 89275708 Authors: Rothstein M;Coppens M Title: Nutritional factors and conditions for the axenic culture of free-living nematodes. Citation: Comparative Biochemistry & Physiology 61B: 99-104 1978 Type: ARTICLE Genes: Abstract: 1. Soy-peptone has been fractionated to yield a series of increasingly purified components which sharply increase the populations of Caenorhabditis briggsae and Caenorhabditis elegans when added to the basal medium. The nutritionally active material appears to be a small polypeptide. 2. C. briggsae and C. elegans routinely reach populations of 150,000/ml or greater in 9 days in still culture, starting from an inoculum of only 500 organisms per ml. C. elegans is particularly sensitive to the depth of the medium. However, large populations can be achieved in deep cultures if continuous shaking is carried out. 3. Panagrellus silusiae shows improved populations if the basal medium is supplemented with the nutritional factor from soy-peptone. However, 0.5% acetic acid or 1% ethanol added to the medium serves equally well. There is no additive effect of ethanol and the factor. ------------------- Key: 332 Medline: 66020574 Authors: Rothstein M;Mayoh H Title: Glycine synthesis and isocitrate lyase in the nematode, C. briggsae. Citation: Biochemical and Biophysical Research Communications 14: 43-47 1964 Type: ARTICLE Genes: Abstract: The metabolism of the nematode Caenorhabditis briggsae differs substantially from that expected of an "animal" species. This organism has at least a limited ability to synthesize "essential" amino acids and, although it utilizes the tricarboxylic acid cycle, does not appear to have a typical cytochrome system. This paper presents evidence for the existence of another interesting metabolic feature, namely the presence of the enzyme "isocytrate lyase" and its utilization by C. briggsae to synthesize the amino acid, glycine. The existence of this pathway was first suspected when it was found that the organism excreted glycine as a major radioactive product after ------------------- Key: 333 Medline: Authors: Rothstein M;Mayoh H Title: Nematode biochemistry IV. On isocitrate lyase in C. briggsae. Citation: Archives of Biochemistry & Biophysics 108: 134-142 1964 Type: ARTICLE Genes: Abstract: The small, free-living nematode, Caenorhabditis briggsae, converts aspartic acid-4-C14 to labeled glycine. Evidence is presented which suggests that the mechanism for this conversion involves the formation of isocitrate and its subsequent splitting by isocitrate lyase to yield glyoxalate and hence, glycine. In support of this mechanism, the enzyme "isocitrate lyase" has been demonstrated in sonic extracts of C. briggsae. ------------------- Key: 334 Medline: Authors: Rothstein M;Mayoh H Title: Nematode biochemistry - VIII. Malate synthetase. Citation: Comparative Biochemistry & Physiology 17: 1181-1188 1966 Type: ARTICLE Genes: Abstract: 1. The presence of malate synthetase has been demonstrated in the four small free-living nematodes, Caenorhabditis briggsae, Panagrellus redivivus, Rhabditis anomala and Turbatrix aceti. Since the organisms possess isocitrate lyase, the complete glyoxalate cycle appears to be present. 2. A sensitive procedure for the detection of labeled malate has been employed to confirm unequivocally the presence of this acid as a product of malate synthetase. ------------------- Key: 335 Medline: Authors: Rothstein M;Nicholas WL Title: Culture methods and nutrition of nematodes and Acanthocephala. Citation: "Chemical Zoology, Volume III. Echinodermata, Nematoda, and Acanthocephala." Florkin M and Scheer BT (eds), Academic Press, NY. : 289-328 1969 Type: REVIEW Genes: Abstract: In order to study properly the nutrition and culture of nematodes, it is desirable to establish the organisms in axenic culture. Only in this way can the metabolic abilities of the nematodes be separated from those of coexisting and interacting organisms. One may settle for a mono-axenic culture, but the best way to attain this is to obtain axenic nematodes and then add the second organism or tissue, for example, alfalfa callus tissue for plant parasitic nematodes (Krusberg, 1961). This chapter will devote itself, in the main, to recent work on the culture and nutrition of nematodes, free-living and parasitic, and will refer only in passing to work already thoroughly reviewed (Dougherty et al., 1959; Nicholas, et al., 1959; Dougherty, 1960). ------------------- Key: 336 Medline: Authors: Rothstein M;Tomlinson GA Title: Biosynthesis of amino acids by the nematode C. briggsae. Citation: Biochimica et Biophysica Acta 49: 625-627 1961 Type: ARTICLE Genes: Abstract: We wish to report what we believe to be the first demonstration of the biosynthesis of "essential amino acids" by a multicellular animal species. Axenic cultures of Caenorhabditis briggsae, a small free-living nematode, were grown at 20C in a chemically defined medium supplemented with a heated liver extract. The amino acid moiety of the medium was replaced with soy-peptone. After two weeks, protein which precipitated was solubilized by treatment of the medium with trypsin for approx. 20 h and the worms were then isolated by centrifugation under sterile conditions....... ------------------- Key: 337 Medline: Authors: Rothstein M;Tomlinson GA Title: Nematode biochemistry II. Biosynthesis of amino acids. Citation: Biochimica et Biophysica Acta 63: 471-480 1962 Type: ARTICLE Genes: Abstract: Axenic cultures of the free-living nematode, Caenorhabditis briggsae, were incubated in water for 6 days in the presence of [1-14C]acetate, [2-14C]acetate, [1-14C]glucose and [2-14C]glycine, respectively. From the last three substrates the worms were found to biosynthesize not only the "non-essential" amino acids represented by glutamic acid, aspartic acid, alanine, glycine, serine and arginine, but also the "essential" amino acids, threonine, tyrosine, valine, leucine, isoleucine, histidine and lysine. This appears to be the first report of such syntheses in an animal species. ------------------- Key: 338 Medline: 78131102 Authors: Russell RL;Johnson CD;Rand JB;Scherer S;Zwass MS Title: Mutants of acetylcholine metabolism in the nematode C. elegans. Citation: "Molecular Approaches to Eucaryotic Genetic Systems" ICN-UCLA Symposia on Molecular & Cellular Biology, Volume 8. Wilcox G, Abelson J and Fox CF (eds), Academic Press, NY. 8: 359-371 1977 Type: REVIEW Genes: ace-1 Abstract: Radiochemical assays based on the selective extraction of either substrate or product from an aqueous reaction volume into an organic scintillator have been developed for acetylcholinesterase and choline acetyltransferase. These rapid, convenient assays have made it possible to screen large numbers of mutant lines for potential enzymatic defects. One mutant with a partial acetylcholinesterase defect and two more with choline acetyltransferase defective mutants have been identified. The acetylcholinesterase defective mutant lacks two of the four isozymic forms of acetylcholinesterase found in wild type C. elegans. Behaviorally, it is selectively defective in the propagation of contractile waves in the body region. Of the two mutants with choline acetyltransferase defects, one is remarkabley paralyzed and uncoordinated, while the other is behaviorally nearly normal. ------------------- Key: 339 Medline: Authors: Rutherford TA;Croll NA Title: Wave forms of C. elegans in a chemical attractant and repellent and in thermal gradients. Citation: Journal of Nematology 11: 232-240 1979 Type: ARTICLE Genes: Abstract: The wave forms and activity patterns of Caenorhabditis elegans were examined on agar in the presence of known chemical attractants (NaCl) and repellents (D-tryptophan), and in thermal gradients. Total activity was reduced in both attractants and repellents. Different combinations of transfers between chemicals were investigated. Two thresholds were found for NaCl: 10-3 M NaCl caused reduced activity; 10-5 M NaCl increased reversals. D- or L-tryptophan influenced neither orientation nor the ability of thermally acclimatized individuals to remain at their eccritic temperatures. ------------------- Key: 341 Medline: 68245408 Authors: Sayre FW;Fishler MC;Humphreys GK;Jayko ME Title: Growth factor studies; changes in reactivity of sulfhydryl groups with activation. Citation: Biochimica et Biophysica Acta 160: 63-68 1968 Type: ARTICLE Genes: Abstract: Observed changes in the reactivity of the essential sulfhydryl groups of a protein growth factor correlate with changes in its biological activity. In activated and nonactivated growth factor, the maximal number of sulfhydryl groups reacting with parachloromercuribenzoate was the same; while the spatial arrangement of the sulfhydryl groups appeared to differ, as evidenced by their different rates of chemical reaction. It is believed that these changes in sulfhydryl reactivity reflect structural changes in the protein molecule and that these structural changes are responsible for the observed changes in its biological activity. ------------------- Key: 342 Medline: Authors: Sayre FW;Hansen EL;Starr TJ;Yarwood EA Title: Isolation and partial characterization of a growth-control factor. Citation: Nature 190: 1116-1117 1961 Type: ARTICLE Genes: Abstract: A growth-promoting factor in liver extracts has been reported in work on a chemically defined medium for the axenic cultivation of the nematode, Caenorhabditis briggsae. An active fraction has now been isolated from horse liver by salt precipitation and column chromatography. The purified material emerged from the column as a discrete protein peak.... ------------------- Key: 343 Medline: Authors: Sayre FW;Hansen EL;Yarwood EA Title: Biochemical aspects of the nutrition of Caenorhabditis briggsae. Citation: Experimental Parasitology 13: 98-107 1963 Type: ARTICLE Genes: Abstract: In an attempt to establish a biochemical and biological tool of multiple potential, we have sought to define the absolute and limited nutritional requirements of Caenorhabditis briggsae. The following has thus far been done: (1) a chemically defined basal medium has been obtained, which sustains life and partial growth but not reproduction, (2) certain biological supplements, which enable the organism to reproduce, have been comparatively evaluated, (3) unexplained freeze-activation of one such supplement has been observed, and (4) through the use of analogues, preliminary suggestions have been derived regarding the action of certain metabolites. ------------------- Key: 344 Medline: Authors: Sayre FW;Reiko TL;Sandman RP;Perez-Mendez G Title: Studies of a growth factor: Fractionation studies and amino acid composition of derived fractions. Citation: Archives of Biochemistry & Biophysics 118: 58-72 1967 Type: ARTICLE Genes: Abstract: A protein growth factor for the nematode, Caenorhabditis briggsae, has been shown, by means of electrophoretic and chromatographic separations, to exist in multiple active forms. The amino acid composition of nine of these active fractions has been shown to be essentially identical, although they were of differing specific activities. It is proposed that these active forms have basically the same primary chemical structure and that the major differences between them is their molecular size. Biological specific activity appears to increase as molecular size increases. Maximal biological activity of most of these fractions could be demonstrated only after the protein was subjected to an activation process. Activation is believed to result from a reversible conformational change within the protein molecule. ------------------- Key: 345 Medline: 79063843 Authors: Schachat F;Garcea RL;Epstein HF Title: Myosins exist as homodimers of heavy chains: Demonstration with specific antibody purified by nematode mutant myosin affinity chromatography. Citation: Cell 15: 405-411 1978 Type: ARTICLE Genes: unc-54 Abstract: The body-walls of Caenorhabditis elegans contain two different myosin heavy chains that associate to form at least two species of myosin. To better define the distribution of these heavy chains in myosin molecules, we have characterized the myosin of C. elegans by immunochemical methods. Specific, precipitating anti-myosin antibody has been prepared in rabbits using highly purified nematode myosin as the immunogen. The difference in reactivity of the anti-myosin antibody with wild-type myosin containing both kinds of heavy chains (designated unc-54 and non-unc-54 heavy chains on the basis of genetic specification) and myosin from the mutant E190 that lacks unc-54 heavy chains indicates that there are antigenic differences between myosin molecules containing unc-54 heavy chains and myosin molecules containing only non-unc-54 heavy chains. Antibody specific for the unc-54 myosin determinants has been prepared by immunoadsorption of anti-myosin antibody with E190 myosin. This specific anti-unc-54 myosin antibody precipitates myosin that contains only unc-54 heavy chains. At the limits of resolution of our immunoprecipitation techniques, we could detect no heterodimeric myosin molecules containing both unc-54 and non-unc-54 heavy chains. The body-wall myosins of C. elegans therefore exist only as homodimers of either class of heavy chain. This specific anti-unc-54 myosin antibody promises to be a valuable tool in elucidating the role of two myosins in body-wall muscle and in molecular characterizations of mutant myosins in C. elegans. We report here the use of this antibody to detect antigenic differences between unc-54 myosin from the wild-type and the muscle mutant E675. In conjuction with the original anti-myosin antibody, other studies show that both unc-54 and non-unc-54 myosins exist within the same body-wall muscle cells and that both myosins are coordinately synthesized during muscle development in C. elegans. We discuss the implications of the self-association of unc-54 and non-unc-54 myosin heavy chains into homodimeric myosins within the same body-wall muscles with respect to the assembly of thick filaments and their organization into a regular lattice. ------------------- Key: 346 Medline: 77242494 Authors: Schachat FH;Harris HE;Epstein HF Title: Actin from the nematode, C. elegans, is a single electrofocusing species. Citation: Biochimica et Biophysica Acta 493: 304-309 1977 Type: ARTICLE Genes: Abstract: We have purified actin from wild type Caenorhabditis elegans animals by three procedures: a purification dependent on the ability of actin to form F-actin, affinity chromatography which preferentially binds G-actin, and co-precipitation of an actin-myosin complex by antimyosin antibodies. Each preparation yields a single elecrofocusing species of actin. Comparison of actin from C. elegans embryos and animals reveals that embryos also have the same single electrofocusing species of actin. ------------------- Key: 347 Medline: 77183615 Authors: Schachat FH;Harris HE;Epstein HF Title: Two homogeneous myosins in body-wall muscle of C. elegans. Citation: Cell 10: 721-728 1977 Type: ARTICLE Genes: unc-54 Abstract: Myosin purified from the body-wall muscle-defective mutant E675 of the nematode, Caenorhabditis elegans, has heavy chain polypeptides which can be distinguished on the basis of molecular weight. On SDS-polyacrylamide gels, bands are found at 210,000 and 203,000 daltons. This is in contrast to myosin from the wild-type, N2, which has a single heavy chain band at 210,000 daltons. Both heavy chains of E675 are found in body-wall muscle. When native myosin from E675 is fractionated on hydroxyapatite, it is separated into myosin containing predominantly one or the other molecular weight heavy chain and myosin containing a mixture of the heavy chains. Comparison of the CNBr fragments of myosin that contains predominantly 210,000 dalton heavy chains with those that contains predominantly 203,000 dalton heavy chains reveals multiple differences. These differences are not explained by the difference in molecular weight of the heavy chains, but may be explained if each type of heavy chain is the product of a different structural gene. Furthermore, because there are fractions which exhibit >80% 210,000 or >80% 203,000 dalton heavy chain, there is myosin which is homogeneous for each of the heavy chains. Although N2 myosin has only a single molecular weight heavy chain, it too is fractionated by hydroxyapatite. By comparing the CNBr fragments of different myosin fractions, we show that N2, like E675, has two kinds of heavy chains. E190, a body-wall muscle-defective mutant in the same complementation group as E675, is lacking the myosin heavy chain affected by the e675 mutation. This property has allowed us to determine by co-purification of labeled E190 myosin in the presence of excess, unlabeled E675 myosin that most, if not all, of the myosin that contains two different molecular weight heavy chains is due to the formation of complexes between homogeneous myosins and not to a heterogeneous myosin. ------------------- Key: 348 Medline: 78131223 Authors: Schachat FH;Harris HE;Garcea RL;LaPointe JW;Epstein HF Title: Studies on two body-wall myosins in wild type and mutant nematodes. Citation: "Molecular Approaches to Eucaryotic Genetic Systems" ICN-UCLA Symposia on Molecular & Cellular Biology, Volume 8. Wilcox G, Abelson J and Fox CF (eds), Academic Press, NY. 8: 373-380 1977 Type: REVIEW Genes: unc-54 Abstract: Native myosin purified from the wild-type, N2, and a body-wall defective mutant, E675, of the nematode contains two myosins, each homogeneous for different heavy chains. These myosins can be resolved from one another on hydroxyapatite and, when cleavaged with CNBr, they yield different peptide-fragments. In E190, one of the homogeneous myosins is absent. e190 and e675 are alleles of the same gene, unc-54. The myosin lacking in E190 is the same one affected in E675. This suggests that unc-54 is the structural gene for a myosin heavy chain. In order to determine the role of these different myosins, we plan to use antibodies to locate the myosins on thick filaments from body-wall muscle. Additionally, we are studying the patterns of synthesis and degradation of the two myosins in the wild-type and muscle-defective mutants in order to discover how the observed stoichiometry is maintained. ------------------- Key: 349 Medline: 79062367 Authors: Schachat F;O'Connor DJ;Epstein HF Title: The moderately repetitive DNA sequences of C. elegans do not show short-period interspersion. Citation: Biochimica et Biophysica Acta 520: 688-692 1978 Type: ARTICLE Genes: Abstract: In these studies we show that the moderately repetitive DNA sequences of Caenorhabditis elegans are not arranged in the characteristic short-period interspersion pattern of most eukaryotes. Rather, the moderately repetitive sequences are arranged in long arrays as in Drosophila and Apis. These findings indicate that this type of arrangement is more phylogenetically diverse and hence less exceptional than previously believed. ------------------- Key: 350 Medline: Authors: Schmidt GD;Kuntz RE Title: Nematode parasites of Oceanica. XVIII. Caenorhabditis avicola sp. n. (Rhabditidae) found in a bird from Taiwan. Citation: Proceedings of the Helminthological Society of Washington 39: 189-191 1972 Type: ARTICLE Genes: Abstract: Caenorhabditis avicola sp. n. is described from one male and three female nematodes from the intestine of a plumbeous water redstart, Rhyacornis fuliginosus (Passeriformes, Turdidae), from Taiwan. It is characterized by the extension of the anterior margins of the peloderan bursa into sharp points, giving the male posterior end an arrowheadlike shape in ventral view, and by the spicules, which are 95 u long. It is postulated that the worms were pseudoparasites, possibly symbionts of an insect ingested by the bird. ------------------- Key: 351 Medline: Authors: Schneider A Title: "Monographie der Nematoden" Citation: Berlin : 1-357 1866 Type: MONOGR Genes: Abstract: ------------------- Key: 352 Medline: 77115898 Authors: Searcy DG;Kisiel MJ;Zuckerman BM Title: Age-related increase of cuticle permeability in the nematode C. briggsae. Citation: Experimental Aging Research 2: 293-301 1976 Type: ARTICLE Genes: Abstract: The external cuticular surface of nematodes, which resembles cellular membranes in certain ways, appears to deteriorate with age. For example, when the permeabilities to radioactive water of young and old nematodes were compared, and the data were corrected for the different surface:volume ratios, the older nematodes were significantly more permeable. In both living and dead nematodes, the same rates of water exchange were observed, indicating that the major route of exchange was probably by passive diffusion through the cuticle rather than by active processes such as swallowing or excreting water. ------------------- Key: 353 Medline: Authors: Searcy DG;MacInnis AJ Title: Measurements by DNA renaturation of the genetic basis of parasitic reduction. Citation: Evolution 24: 796-806 1970 Type: ARTICLE Genes: Abstract: It has been suggested that parasitic organisms have a simpler genome than their free-living counterparts. Measurements by reciprocal DNA hybridizations in vitro have shown that the parasitic plant Cuscuta californica has a smaller genome than several closely related autotrophic plants. These studies have the shortcoming of detecting only the hybridization of the highly repetitive sequences of DNA; the non-repetitive sequences react too slowly to hybridize significantly under the conditions used. The size of the genome may also be determined by DNA renaturation. Denatured DNA fragments can be made to renature in vitro, forming a specifically base-paired structure as in native DNA. As predicted theoretically, and as confirmed empirically, the rate of renaturation is inversely related to the molecular weight of the entire DNA molecule of phages and bacteria. The DNA of higher organisms renatures faster than would be predicted from the haploid complement of DNA because of the presence of highly repetitive DNA sequences. However, the rate of renaturation of the slowest reacting components can be used to measure the "kinetic complexity" of an organism, which is a measure of the total number of different sequences in the DNA of an organism. The rate of renaturation of the non-repetitive DNA of higher organisms is much slower than the rate with simpler organisms. Some published experiments have taken 20 days. Therefore we modified the conditions so that significant renaturation can be obtained in a much shorter time. Since there are several different ways to plot the data, we will show why we have used the rate plot suggested by Wetmur and Davidson. Measurements on the rates of renaturation of the plant DNA's show that the parasitic plant Cuscuta has a simpler genome than closely related autotrophic plants; these measurements confirm the results of the earlier hybridization studies. Measuring the rate of renaturation has the added advantage that the size of the genome can be determined in units of molecular weights, thus allowing comparisons between distantly related organisms. Our measurements on parasitic and free-living nematodes and flatworms show that a ------------------- Key: 354 Medline: Authors: Singh RN;Sulston JE Title: Some observations on molting in C. elegans. Citation: Nematologica 24: 63-71 1978 Type: ARTICLE Genes: lin-5 lin-6 Abstract: Moulting of Caenorhabditis elegans has been observed by Nomarski interference contrast microscopy, and by electron microscopy of animals at selected stages. The wild type, cell division mutants and animals in which cells had been ablated by a laser microbeam were examined. The median lateral hypodermis, or "seam", is required for the formation of alae and for dauer larva maturation. During cuticle deposition, large Golgi bodies are seen in the seam cells. The excretory system is not essential for moulting. ------------------- Key: 355 Medline: Authors: Smith RM;Peterson WH;McCoy E Title: Oligomycin, a new antifungal antibiotic. Citation: Antibiotics & Chemotherapy 4: 962-970 1954 Type: ARTICLE Genes: Abstract: Although the majority of antibiotics are of interest because of their activity against bacteria, a vigorous search is underway for antifungal agents. This effort stems from the resistance of many animal and plant pathogens to the known antibiotics. As a result of this effort, there are already about 50 well-defined antibiotics that are more or less active against the filamentous fungi, and because of the active search now in progress, many more such agents will undoubtedly be uncovered in the near future. These antibiotics can be classified into three groups based on the microorganisms that produce them. Among bacteria, the genus Bacillus has so far proved the most fruitful source of antibiotics. Examples of such antibiotics are bacillomycin, fungistatin, mycosubtilin, and toximycin. Those that have been sufficiently purified to judge are of polypeptide nature. Antifungal antibiotics derived from fungi are produced by a number of genera. Examples of such antibiotics are alternaric acid, aspergillic acid, gladiolic acid, glutinosin, griseofulvin, patulin, tricothecin, and viridin. The actinomycetes have yielded the largest number of antifungal agents, among them actinomycin, Actidione, antimycin, ascosin, candicidin, endomycin, fradicin, helixin, Rimocidin, and thiolutin. The antifungal antibiotics have not found widespread use because of inherent toxicity or other unfavorable properties. A few have been tried with some success against the agents of plant disease, and it may be in this and other nonmedical fields that they will have their greatest use. The purpose of this paper is to report a presumably new antifungal antibiotic, oligomycin. ------------------- Key: 356 Medline: Authors: Soos A Title: Rhabditis carpathicus spec. nov. eine neue in Sphagnum-Mooren lebende Nematode/ Citation: Fragmenta Faun. Hungarica 4: 115-119 1941 Type: ARTICLE Genes: Abstract: ------------------- Key: 357 Medline: Authors: Spaull VW Title: Qualitative and quantitative distribution of soil nematodes of Signy Island South Orkney Islands. Citation: British Antarctic Survey Bulletin 33: 177-184 1973 Type: ARTICLE Genes: Abstract: ------------------- Key: 358 Medline: Authors: Starck J Title: Radioautographic study of RNA synthesis in C. elegans (Bergerac variety) oogenesis. Citation: Biology of the Cell 30: 181-182 1977 Type: ARTICLE Genes: Abstract: Each of two ovarian tubes of Caenorhabditis elegans represents an extremely simple organization being totally deprived of follicular or nutrient cells and showing a linear progression of the oocytes. In this organ, syntheses take place with a very high rate. At 18C, two eggs are formed in one hour, and the whole volume of the ovary is transformed into eggs every seven hours. Therefore, the metabolism of RNA in this exceptionally active organ deserves to be better known. Until now, only a cytological study with Unna staining has been devoted to this subject. This preliminary work describes the original method of incubation allowing the use of radioactive precursor for RNA synthesis study. ------------------- Key: 359 Medline: Authors: Stromberg BE;Soulsby EJL Title: Heterologous helminth induced resistance to Ascaris suum in Guinea pigs. Citation: Veterinary Parasitology 3: 169-175 1977 Type: ARTICLE Genes: Abstract: The protection inducing capacity of Toxocara canis, Ancylostoma caninum, Haemonchus cortortus, Caenorhabditis briggsae and Turbatrix aceti given via the mesenteric vein to a challenge infection with Ascaris suum was evaluated. Embryonated eggs and second stage larvae of T. canis and infective larvae of A. caninum were able to induce a statistically significant level of protective immunity, while the other nonrelated helminths were unable to protect against a challenge infection. ------------------- Key: 361 Medline: Authors: Sudhaus W Title: Zur Systematik, Verbreitung, Okologie und Biologie neuer und wenig bekannter Rhabditiden (Nematoda) 2. Teil. Citation: Zool. Jb. Syst. Bd. 101: 417-465 1974 Type: ARTICLE Genes: Abstract: Five new species of the genus Rhabditis are described (Rh. riemanni n. sp., Rh. remanei n. sp., Rh. reciproca n. sp., Rh. blumi n. sp., and Rh. valida n. sp.) belonging to five subgenera (Crustorhabditis, Caenorhabditis, Rhabditis, Cephaloboides, and Pellioditis). The descriptions of four additional species are revised (Rh. ocypodis Chitwood, Rh. scanica Allgen, Rh. plicata Volk, and Rh. bengalensis Timm). The new subgenus Crustorhabditis n. subgen. derives from the paraphyletic subgenus Mesorhabditis. The species of the former group show a transition from living in littoral seaweed deposits to an obligate association with amphibious crabs (Crustacea). Information about the distribution, ecology, biology and ethology of all these species is presented (with two distribution maps, one for Rh. marina for comparison). Supplementary notes are given from Protorhabditis oxyuroides Sudhaus and Rhabditis tripartita von Linstow. ------------------- Key: 362 Medline: Authors: Sukul NC;Croll NA Title: Influence of potential difference and current on the electrotaxis of C. elegans. Citation: Journal of Nematology 10: 314-317 1978 Type: ARTICLE Genes: Abstract: C. elegans responds directionally to a DC current. The response may be to the anode or cathode, depending on the current, potential difference, and ionic concentration of KCl. Tracks of the responding nematodes show that electrotaxes are genuine orientation phenomena. The directional movement is not due to the passive movement of nematodes or to the influence of currents on the muscular physiology; electrotaxes are mediated sensorily. Details of the response are described. ------------------- Key: 363 Medline: 76269912 Authors: Sulston JE Title: Post-embryonic development in the ventral cord of C. elegans. Citation: Philosophical Transactions of the Royal Society of London 275B: 287-298 1976 Type: ARTICLE Genes: nuc-1 Abstract: 56 nerve cells are added to the ventral cord and associated ganglia of Caenorhabditis elegans at about the time of the first larval moult. These cells are produced by the uniform division of 13 neuroblasts followed by a defined pattern of cell deaths. Comparison with the data in the previous paper suggests that there is a relationship between the ancestry of a cell and its function. The significance of programmed cell death is discussed. ------------------- Key: 364 Medline: 74271162 Authors: Sulston JE;Brenner S Title: The DNA of C. elegans. Citation: Genetics 77: 95-104 1974 Type: ARTICLE Genes: Abstract: Chemical analysis and a study of renaturation kinetics show that the nematode, Caenorhabditis elegans, has a haploid DNA content of 8 X 10(7) base pairs (20 times the genome of E. coli). Eighty-three percent of the DNA sequences are unique. The mean base composition is 36% GC; a small component, containing the rRNA cistrons, has a base composition of 51% GC. The haploid genome contains about 300 genes for 4S RNA, 110 for 5S RNA, and 55 for (18 + 28)S RNA. ------------------- Key: 365 Medline: 76025558 Authors: Sulston J;Dew M;Brenner S Title: Dopaminergic neurons in the nematode Caenorhabditis Citation: Journal of Comparative Neurology 163: 215-226 1975 Type: ARTICLE Genes: cat-1 cat-2 cat-3 cat-4 cat-5 flu-4 unc-18 unc-51 Abstract: Dopamine is the putative transmitter of eight neurons in the hermaphrodite form of the nematode Caenorhabditis elegans. These include the cephalic and deirid neurons, which are believed to be mechanosensory. The male has an additional six dopaminergic neurons in the tail. Mutants have been selected which have defects in the formaldehyde induced fluorescence and lack dopamine to varying degrees, but they are not insensitive to touch. The dopaminergic neurons of C. elegans are compared with the homologous neurons in Ascaris lumbricoides. ------------------- Key: 366 Medline: 77116565 Authors: Sulston JE;Horvitz HR Title: Post-embryonic cell lineages of the nematode, Caenorhabditis elegans. Citation: Developmental Biology 56: 110-156 1977 Type: ARTICLE Genes: Abstract: The number of nongonadal nuclei in the free-living soil nematode Caenorhabditis elegans increases from about 550 in the newly hatched larva to about 810 in the mature hermaphrodite and to about 970 in the mature male. The pattern of cell divisions which leads to this increase is essentially invariant among individuals; rigidly determined cell lineages generate a number of progeny cells of strictly specified fates. These lineages range in length ------------------- Key: 367 Medline: Authors: Tattar TA;Stack JP;Zuckerman BM Title: Apparent nondestructive penetration of C. elegans by microelectrodes. Citation: Nematologica 23: 267-269 1977 Type: ARTICLE Genes: Abstract: Free-living nematodes are sometimes used as models for fundamental studies of biological problems such as aging, genetics and behavior. In these it would be advantageous if measured amounts of drugs, nematicides or other substances could be introduced into parts of nematodes. One possibility is injection by a glass microcapillary inserted through the cuticle. However, nematodes have a high turgor pressure and when the body is pierced the nematode usually bursts. We report penetration of Caenorhabditis elegans (Maupas) without apparent harm. ------------------- Key: 368 Medline: 76043799 Authors: Tilby MJ;Moses V Title: Nematode ageing. Automatic maintenance of age synchrony without inhibitors. Citation: Experimental Gerontology 10: 213-223 1975 Type: ARTICLE Genes: Abstract: A technique is described for the continuous growth of an age-synchronized population of Caenrohabditis elegans. After initial isolation of newly hatched individuals from a mixed age culture, synchrony through the reproductive phase was sufficiently well maintained to ensure that over 90% of the post-reproductive population belonged to the original generation. The technique is based on culturing the nematodes on the upper surface of a fine stainless steel mesh through which only larvae, but not adults, are small enough to burrow. It largely overcomes serious disadvantages of the two previously used methods for maintaining synchrony which were based on the use of inhibitors or the manipulation of individual worms. Supplementary techniques are described for the handling and initial synchronization of the worms which are cultured in a sterile completely defined medium. General features of the development and senescence of the worms under our conditions are reported. Mean life span (50% survival) was approx. 58 days and maximum longevity in excess of 80 days. Reproduction lasted from the 5th to about the 26th day of age and its termination coincided with a short period of high mortality. Growth in size of the worms ceased during the reproductive period but recommenced for about 25 days in worms surviving the post-reproductive mortality. ------------------- Key: 369 Medline: Authors: Tiner JD Title: A preliminary in vitro test for anthelminthic activity. Citation: Experimental Parasitology 7: 292-305 1958 Type: ARTICLE Genes: Abstract: The rate of discovery of new anthelmintics has increased but little during the past two decades. The same interval has been characterized by accelerated progress in chemotherapy, and especially by the appearance of various and diverse antibiotics discovered with in vitro screening tests. Lamson and Brown (1936) stated that both in vitro and in vivo anthelmintic tests aid in determining the probable action of chemicals in the host. Subsequently, in vivo tests have been increasingly emphasized by helminthologists, even for the initial evaluation of untried substances. Steward discussed screening methods, and described a preliminary test using rats doubly infected with intestinal and caecal nematodes. Choices of methods by various investigators have been influenced by an assumption that the antinematode activity of phenothiazine is detectable only in vivo, but this assumption is no longer entirely tenable. Anthelmintic tests should be sensitive enough to permit recognition of inhibitors of single vital enzymes. An ideal test would require only minute quantities of chemicals for titration against representative species and stages of the more economically important parasites. The present paper describes a procedure that begins to meet these requirements. It consumes less than 10 mg of each substance, and one operator can process about 100 samples per month. Phenothiazine serves as a standard of reference if developing trichostrongyle nematodes are utilized as test organisms. That chemical is characterized by a general ineffectiveness against members of the nematode subfamily Rhabditinae, together with a high toxicity for embryos and ------------------- Key: 371 Medline: Authors: Tomlinson GA;Rothstein M Title: Nematode Biochemistry I. Culture Methods. Citation: Biochimica et Biophysica Acta 63: 465-470 1962 Type: ARTICLE Genes: Abstract: A simple procedure has been developed by which the nematode Caenorhabditis briggsae can be routinely grown and handled in sufficient numbers for biochemical studies. Culture of the nematode was carried out in media based on either soy-peptone or soy-peptone-yeast extract, both supplemented with liver extract. ------------------- Key: 372 Medline: Authors: Turner RH;Green CD Title: Preparation of biological material for scanning electron microscopy by critical point drying from water miscible solvents. Citation: Journal of Microscopy 97: 357-363 1973 Type: ARTICLE Genes: Abstract: Nematodes and mildew-infected barley leaves when examined in the scanning electron microscope after critical point drying (CPD) from sulphur dioxide (critical temperature 157.7C) showed no obvious physical damage, but the specimens had a surface deposit which was probably heat damaged natural waxes. The nematode Caenorhabditis elegans and clover roots (Trifolium subterraneum) showed no physical or heat damage after CPD from monochlorodifluoromethane (Freon 22, critical temperature 96C). The hyphae and conidia of unfixed mildew on barley were damaged after CPD from Freon 22, probably due to the Freon extracting lipids from the cell walls. Freon 22 was preferred for most specimens as it is cheap, easy to get ------------------- Key: 373 Medline: 76140558 Authors: Vanderslice R;Hirsh D Title: Temperature-sensitive zygote defective mutants of C. elegans. Citation: Developmental Biology 49: 236-249 1976 Type: ARTICLE Genes: zyg-1 zyg-2 zyg-3 Abstract: Three generally complementing temperature-sensitive mutants of Caenorhabditis elegans have been studied. Each of the three mutants has two critical times of temperature sensitivity and two distinct corresponding phenotypes. Exposure to high temperature during gonadogenesis blocks the production of zygotes. Exposure of adults to high temperature interrupts embryogenesis of the zygotes being produced. Each of the mutants carries an autosomal mutation with a maternal effect. These mutants indicate that the individual temperature-sensitive functions are required at least twice during development and that early embryogenesis is dependent on the contribution of these functions from the maternal gonad. ------------------- Key: 374 Medline: Authors: Vanfleteren JR Title: Amino acid requirements of the free-living nematode C. briggsae. Citation: Nematologica 19: 93-99 1973 Type: ARTICLE Genes: Abstract: Washed yeast ribosomes promote growth and reproduction of C. briggsae, even when supplemented to the basal medium at dosages too low to provide the organisms with sufficient amounts of essential amino acids. Hence, a re-investigation of the amino acid requirements of C. briggsae by single and multiple omission of amino acids from the basal medium revealed unambiguously that arginine, histidine, lysine, tryptophan, phenylalanine, methionine, threonine, leucine, isoleucine and valine are not synthesized at levels to permit reproduction; they are called essential amino acids. The requirement for arginine and isoleucine however appears to be less clear-cut. On the contrary, evidence is presented that alanine, asparagine, cysteine, glutamate, glutamine, glycine, proline, serine and tyrosine can be synthesized at adequate levels; they are called non-essential amino acids. In addition it was shown that multiple omission of the non-essential amino acids in not deleterious. This is believed to be an important step towards the development of a minimum essential medium (MEM) for growth and ------------------- Key: 375 Medline: 74132550 Authors: Vanfleteren JR Title: Nematode growth factor. Citation: Nature 248: 255-257 1974 Type: ARTICLE Genes: Abstract: Free-living nematodes, grown axenically in a chemically defined medium, might be of considerable interest as model systems for studying the fundamental aspects of genetics and differentiation of higher organisms. Several species of free-living nematodes have been cultured serially in axenic media. Unfortunately, the chemically defined medium in current use, Caenorhabditis briggsae Maintenance Medium (CbMM), does not support continuous growth unless supplemented with a 'growth factor' that can be derived from various biological sources. ------------------- Key: 376 Medline: Authors: Vanfleteren JR Title: The nature of a nematode growth factor I. Growth and maturation of C. briggsae on ribonucleoprotein particles. Citation: Nematologica 21: 413-424 1975 Type: ARTICLE Genes: Abstract: The biological activity of ribonucleoprotein (RNP) particles from yeast, E. coli, mammalian liver, HeLa cells and pea seedlings on maturation and reproduction of the free-living nematode Caenorhabditis briggsae has been evaluated. RNP particles from yeast, E. coli, mammalian liver and HeLa cells are biologically highly active. The minimum doses permitting maturation and reproduction within 7 days were 3.4, 13, 9.8, and 3.2 ug protein/ml respectively. The addition of haemin chloride at a final concentration of 10 ug/ml did not improve biological activity. RNP particles from E. coli, washed with 1M salt were inactive. Pea seedling particles were inactive, but became active upon addition of haemin chloride to the medium. It is assumed that the activity of RNP preparations is due to a contaminating haem protein. ------------------- Key: 377 Medline: Authors: Vanfleteren JR Title: The nature of a nematode growth factor II. Growth and maturation of C. briggsae on haem proteins. Citation: Nematologica 21: 425-437 1975 Type: ARTICLE Genes: Abstract: The growth promoting activity of cytochrome c, catalase, haemiglobin, myoglobin, horse radish peroxidase, yeast L-lactate dehydrogenase and cytochrome c reductase on maturation and reproduction of Caenorhabditis briggsae has been evaluated. Cytochrome c, catalase, haemiglobin, myoglobin, and horse radish peroxidase were biologically active when properly precipitated. The biological activity of horse radish peroxidase (assayed as the peroxidase-antiperoxidase immunoprecipitate) was greatly increased upon addition of haemin to the medium. This is easily explained on the assumption that much haem could have been split off from the protein during the activation treatment. Yeast L-lactate dehydrogenase and cytochrome c reductase did not contain sufficient amounts of haem after the activation treatment. They were inactive in haemin lacking basal medium, but highly active in basal medium supplemented with haemin. These experiments support the idea that the third and so far unknown component (the other components being sterols and haem) of the growth factor complex is not a protein of particular nature, but rather any convenient vector for the haem component. ------------------- Key: 378 Medline: Authors: Vanfleteren JR Title: The nature of a nematode growth factor. III. Growth and maturation of C. briggsae on protein-haemin Citation: Nematologica 22: 103-112 1976 Type: ARTICLE Genes: Abstract: The growth promoting activity of protein-haemin co-precipitates from ferritin, apoferritin, transferrin, bovine serum albumin, conalbumin and egg white on maturation and reproduction of C. briggsae has been evaluated. Ferritin, apoferritin and transferrin were found to be biologically highly active in the presence of haemin. Bovine serum albumin, conalbumin and egg white were slightly active. Maturation and reproduction of C. briggsae on the coagulates from bovine serum albumin and egg white were nearly independent of the dose administered, probably because the limited availability of haemin from these coagulates permits but slow growth, even in the presence of abundant proteinaceous material. Bovine serum albumin, egg white and conalbumin failed to support continuous growth of C. briggsae. It is supposed that the limited availability of haemin from these coagulates inhibits normal maturation and reproduction of the F1 progeny. These experiments clearly demonstrate the requirement for particulate haem. The requirement for ------------------- Key: 379 Medline: 76257725 Authors: Vanfleteren JR Title: Large scale cultivation of a free-living nematode (C. elegans). Citation: Experientia 32: 1087-1088 1976 Type: ARTICLE Genes: Abstract: A method is presented for the large scale cultivation of the free-living nematode Caenorhabditis elegans, using continuous aeration and agitation in glass ware (stirrer flasks) developed for the continuous culture of suspended cells. With this technique, populations up to 10e9 nematodes may be obtained in a 10 l culture in less than 6 weeks with an inoculum of some 50 worms. Costs can be reduced by using an inexpensive yeast extract, available from the food industry. ------------------- Key: 380 Medline: Authors: Vanfleteren JR Title: Axenic culture of free-living, plant-parasitic, and insect-parasitic nematodes. Citation: Annual Review of Phytopathology 16: 131-157 1978 Type: REVIEW Genes: Abstract: Two excellent reviews, one of them recent, are available on the axenic culture of nematodes. Therefore, the present article is mainly an outline of the present state of nematode culture research and is limited to surveying reports that have a significant bearing on our understanding of nematode growth in axenic culture. The first section covers nutritional requirements with special attention to the material needed for growth and reproduction in repeated subculture. Since nematode nutrition has largely been studied on the free-living nematode Caenorhabditis briggsae, I first scrutinize the dietary requirements of this species and extend our knowledge to other nematodes in axenic culture thereafter. In particular, I demonstrate how a general understanding of the nature of the growth factor emerges from a discriminatory analysis of existing knowledge and I support this concept with experimental evidence; also I attempt to reconcile this concept with some older as well as more recent controversial findings. The next section is devoted to culture methodology and covers some new techniques that render nematodes convenient as model organisms for scientific research. Throughout this review I use the terminology proposed by Dougherty for describing culture conditions with respect to the number of coexisting species and the different degrees of chemical differentiation of the media. The term axenic means free of contaminating organisms and supersedes the less suitable adjectives sterile or aseptic. Monoxenic cultures contain one additional species or tissue (e.g. alfalfa callus tissue), dixenic two and so on. Species that are studied in xenic cultures are reared in interaction with several unidentified organisms. Media that are chemically undefined are called oligidic. Those consisting of a defined basal portion and a less defined supplement are meridic. Holidic media are fully defined and contain ------------------- Key: 381 Medline: 77246411 Authors: Vanfleteren JR;Avau H Title: Selective inhibition of reproduction in aminopterin-treated nematodes. Citation: Experientia 33: 902-904 1977 Type: ARTICLE Genes: Abstract: Aminopterin was applied to the free-living nematode Caenorhabditis briggsae and subsequent growth was recorded. Nematode populations, containing all developmental stages and selected juvenile stages, were exposed to the drug in both growth-promoting and non-promoting media. It is suggested that aminopterin creates a specific requirement for thymine in thymine-free medium. In otherwise growth-promoting medium, aminopterin-induced thymine deficiency will lead to progressively unbalanced growth and maturation and hence to sterility even after removal of the drug. The omission of essential amino acids from the medium during thymine starvation prevents larval growth and results in better reproduction and faster proliferation in animopterin-free medium. The 4 juvenile stages exhibit a different response to thymine starvation created by aminopterin. ------------------- Key: 382 Medline: 89337642 Authors: Vanfleteren JR;Neirynck K;Huylebroeck D Title: Nematode chromosomal proteins-I. Isolation of chromatin and preliminary characterization of the chromosomal proteins of C. elegans. Citation: Comparative Biochemistry & Physiology 62B: 349-354 1979 Type: ARTICLE Genes: Abstract: 1. A procedure is described which gives clean chromatin preparations from the free-living nematode Caenorhabditis elegans. It involves homogenization using glass beads, collection of the precipitate from a low speed centrifugation, removal of cell membranes with Triton X- 100, several washes with 0.14 M NaCl, sucrose density gradient centrifugation, a cycle of extraction and reprecipitation using dilute Tris buffer and 0.14 M NaCl respectively, and final extraction of the purified deoxyribonucleoprotein in 10 mM Tris-HCl (pH 8). 2. Acidic urea gel electrophoresis of the histones from C. elegans yielded 4 main groups which were preliminary identified as H1, H2a (+ H3?), H2b, H4 and moved on the gels in that order of increasing mobility. the coincidence of histone H3 with H2a was putative, but its presence was firmly suggested by the generation of a dimeric form in oxidizing conditions. 3. By SDS-Tris-glycine gel electrophoresis of the non-histone chromosomal proteins of C. elegans, about 18 proteins were distinguished with molecular weights ranging from 15,000 to 100,000 daltons. ------------------- Key: 383 Medline: Authors: Vanfleteren JR;Roets DE Title: The influence of some anthelmintic drugs on the population growth of the free-living nematodes C. briggsae and Turbatrix aceti (Nematoda: Rhabditida). Citation: Nematologica 18: 325-338 1972 Type: ARTICLE Genes: Abstract: Drugs with specific and intensive toxicity to nematodes, termed nematicides, might be suitable for the isolation of nematicide-resistant mutants. For this purpose, several medical anthelmintics, namely ascaridol, bephenium, d-tubocurarine chloride, piperazine adipate, piperazine hydrate, phenothiazine, n-hexylresorcinol, dithiazanine iodide, pyrvinium pamoate and thiabendazole have been tested for their influence on the population growth of Caenorhabditis briggsae and Turbatrix aceti. Ascaridol, bephenium, d-tubocurarine chloride, piperazine adipate, piperazine hydrate, phenothiazine and n-hexylresorcinol were shown to have a small to moderate toxicity. The effect of thiabendazole on population growth of C. briggsae is moderate, but its action on T. aceti is intense. Finally, dithiazanine iodide and pyrvinium pamoate are very toxic to both nematodes. It is concluded that dithiazanine iodide, pyrvinium pamoate and thiabendazole (restricted to T. aceti) might be suitable for the isolation of resistant ------------------- Key: 385 Medline: Authors: von Ehrenstein G Title: A model system for developmental biology and behavioral genetics. Citation: Jahrbuch der Max-Planck-Gesellschaft : 38-60 1973 Type: REVIEW Genes: Abstract: In German. ------------------- Key: 386 Medline: Authors: Wahab A Title: Untersuchungen uber Nematoden in den Drusen des Kopfes der Ameisen (Formicidae). Citation: Zeitschrift fur Morphologie und Oekologie der Tiere 52: 33-92 1962 Type: ARTICLE Genes: Abstract: ------------------- Key: 387 Medline: 73209591 Authors: Ward S Title: Chemotaxis by the nematode C. elegans: Identification of attractants and analysis of the response by use of mutants. Citation: Proceedings of the National Academy of Sciences USA 70: 817-821 1973 Type: ARTICLE Genes: bli-1 bli-4 unc-23 Abstract: The nematode Caenorhabditis elegans is attracted by at least four classes of attractants: by cyclic nucleotides, cAMP and cGMP; by anions, Cl-, Br-, I-; by cations, Na+, Li+, K+, Mg+; and by alkaline pH values. The nematode's behavioral response to gradients of these attractants involves orientation and movement up the gradient, accumulation, and then habituation. Comparison of the tracks of wild-type and mutant animals responding to gradients of attractants indicates that sensory receptors in the head alone mediate the orientation response and that the direction of orientation is determined by the lateral motion of the head. Therefore, the orientation response is ------------------- Key: 388 Medline: Authors: Ward S Title: The use of mutants to analyze the sensory nervous system of C. elegans. Citation: "The Organization of Nematodes." Croll NA (ed), Academic Press, NY. : 365-382 1976 Type: REVIEW Genes: che-1 che-2 che-3 mec-1 sma-1 unc-23 unc-52 Abstract: The isolation of behavioural mutants of an organism can provide a variety of strains that are somehow altered in normal neural function. By physiological, anatomical, and biochemical analysis of such alterations it should be possible to correlate the behavioural defect with an underlying neurological defect. From such correlations, the functional role of the defective elements of the nervous system can be deduced. For such analysis the mutations can be thought of as a dissecting tool used to cut parts of the nervous system to determine the behavioural consequences of such cuts. Pursuit of the underlying defects in behavioural mutants leads rapidly beyond just the analysis of neural function. One is let to ask what kinds of cuts are made by the genetic dissecting tool? What alterations in a nervous system can be introduced by single gene mutations? How did the defective gene product cause such an alteration? Such questions about the genetic specification of the development of the nervous system may also be approached by the study of behavioural mutants. In this chapter, I will first illustrate some of the ways that behavioural mutants of Caenorhabditis elegans can be used to study the function of the sensory nervous sytem and then show how the anatomical analysis of such mutants leads to questions about neural ------------------- Key: 389 Medline: 78079173 Authors: Ward S Title: Invertebrate neurogenetics. Citation: Annual Review of Genetics 11: 415-450 1977 Type: REVIEW Genes: Abstract: In 1967, Benzer demonstrated that phototactic mutants in Drosophila melanogaster could be induced and readily isolated by countercurrent selection. This demonstration stimulated further experimentation in selection and characterization of behavioral mutants in inbred organisms. In the ten years since Benzer's paper, hundreds of mutants altering the nervous system have been identified and studied, not only in Drosophila, but also in nematodes, protozoa, crickets, mice, and other organisms. This review describes recent studies of such mutants and attempts to assess the current status of this genetic approach to neurobiological problems...... ------------------- Key: 390 Medline: Authors: Ward S Title: Use of nematode behavioral mutants for analysis of neural function and development. Citation: "Approaches to the Cell Biology of Neurons" Society for Neuroscience Symposia, Vol. II Sixth Annual Meeting, Toronto, Nov. 1976. Cowan WM and Ferrendelli JA (eds), Society for Neuroscience. : 1-26 1977 Type: REVIEW Genes: che-1 che-2 che-3 mec-1 unc-23 Abstract: The soil nematode Caenorhabditis elegans was selected 11 years ago by Sydney Brenner as an experimental organism suitable for the isolation of many behavioral mutants and small enough for anatomical analysis of such mutants with the electron microscope. Two distinct goals motivated the initial studies of this organism: first, the hope that some of the mutants would have simple anatomical alterations that could be directly correlated with their behavioral defects, allowing the assignment of specific functions to specific neurons, and second, the hope that the detailed analysis of the kinds of alterations induced by individual mutations and the classes of cells affected by given mutations would reveal general features of the genetic program that specifies the development of the organism. Over the past 11 years the number of investigators working on C. elegans has increased to about 75 and is still growing. Nearly 3,000 different mutants have been isolated and different investigators are pursuing their effects on different cells. My own research is in the development of the nervous system. In particular, I would like to learn something about the workings of the complex black box that connects individual genes to the determination of the morphology of developing neurons. Are there gene products whose specific function is to determine the morphology of cells? If so, what are these gene products and how do they act in the developing cell? One would anticipate that mutations in such hypothetical genes would cause specific morphological alterations in cells. Because the morphology of a neuron determines its function, by selecting behavioral mutants altered in the function of the nervous system one might commonly find mutants that alter the morphology of neurons, and some of these might be in specific morphological genes. It is my hope that it will be possible to compare such mutants to the wild type in order to identify the defective gene products and thereby learn something about the role of normal gene products in determining the development of neurons. In this paper I will first summarize the results of several years' work on one specific class of mutants in the nematode, sensory mutants, work performed both in my laboratory and that of my colleagues Jim Lewis and Jonathan Hodgkin. Second, I will discuss frankly some of the difficulties and frustrations we have experienced in trying to interpret the effects of these specific mutants. Some of these difficulties illustrate problems endemic to genetic studies of development. Third, I will describe the more recent work performed in my labortory that is being directed toward genetic analysis of the structure and function of a ------------------- Key: 391 Medline: Authors: Ward S Title: Nematode chemotaxis and chemoreceptors. Citation: "Receptors and Recognition Series B. Taxis and Behavior. Elementary Sensory Systems in Biology." Hazelbauer GL (ed), Halsted Press, Wiley NY. : 141-168 1978 Type: REVIEW Genes: che-1 che-3 unc-23 Abstract: A small sightless worm crawling among particles of soil and decaying vegetation must have a variety of chemical senses to locate bacteria for food and to avoid poisons and predators. What chemicals are sensed? How many different kinds of receptor molecules are there? On which neurons are the receptors located? How sensitive are these neurons? How is the detection of a chemical communicated to the worm's central nervous system and converted into a behavioral response? All of these questions have been addressed in studies of the soil nematode Caenorhabditis elegans. This organism has recently become the subject of intensive genetic, behavioral and anatomical studies. The behavior that has been examined in most detail is chemotaxis. This chapter will review what is known about C. elegans chemotaxis and will present a number of new observations. The results will be interpreted in terms of a specific model of chemoreceptor function. The problem of analysis of central nervous system processing of chemosensory neuron information will be discussed briefly. ------------------- Key: 392 Medline: 80047624 Authors: Ward S;Carrel JS Title: Fertilization and sperm competition in the nematode C. elegans. Citation: Developmental Biology 73: 304-321 1979 Type: ARTICLE Genes: fem-1 fer-1 Abstract: The process of fertilization by hermaphrodite and male sperm is described. In the hermaphrodite fertilization occurs in the spermatheca by the first sperm to contact the oocyte. Other sperm that contact the oocyte are swept into the uterus but they crawl back into the spermatheca to fertilize subsequent oocytes so that every sperm fertilizes an oocyte. Not every oocyte is fertilized because oocytes are made in excess. Fertilization triggers active movement of oocyte cytoplasmic granules. Sperm penetration is not required for this activation because fertilization-defective mutant sperm trigger activation without penetration. When males copulate with hermaphrodites, their sperm is deposited in the uterus beneath the vulva. These sperm crawl up the uterus to the spermatheca where they displace the hermaphrodite sperm from the spermathecal walls and preferentially fertilize the oocytes. This preferential fertilization appears to be due in part to inhibition of hermaphrodite sperm fertility by the male sperm. The male sperm competition ensures male sperm utilization and thus some outcrossing in a population ------------------- Key: 393 Medline: 78149180 Authors: Ward S;Miwa J Title: Characterization of temperature-sensitive, fertilization-defective mutants of the nematode C. elegans. Citation: Genetics 88: 285-303 1978 Type: ARTICLE Genes: che-1 fer-1 Abstract: The isolation and characterization of three Caenorhabditis elegans temperature-sensitive mutants that are defective at fertilization are described. All three are alleles of the gene fer-1. At the restrictive temperature of 25C, mutant hermaphrodites make sperm and oocytes in normal numbers. No oocytes are fertilized, although they pass through the spermatheca and uterus normally. The oocytes can be fertilized by sperm transferred by wild-type males, indicating that the mutant defect is in the sperm. The temperature-sensitive period for the mutants coincides with spermatogenesis. Sperm made by mutants at 25C cannot be distinguished from wild-type sperm by light microscopy. The sperm do contact oocytes in mutant hermaphrodites, but do not fertilize. Mutant sperm appear to be nonmotile. Mutant males are also sterile when grown at 25C. They transfer normal numbers of sperm to hermaphrodites at mating, but these sperm fail to migrate to the spermatheca and are infertile. The phenotype of these mutants is consistent with a primary defect in sperm motility, but the cause of this defect is not known. ------------------- Key: 394 Medline: 75095932 Authors: Ward S;Thomson N;White JG;Brenner S Title: Electron microscopical reconstruction of the anterior sensory anatomy of the nematode C. elegans. Citation: Journal of Comparative Neurology 160: 313-337 1975 Type: ARTICLE Genes: Abstract: The complete structure of the anterior sensory nervous system of the small nematode C. elegans has been determined by reconstruction from serial section electronmicrographs. There are 58 neurons in the tip of the head. Fifty-two of these are arranged in sensilla. These include six inner labial sensilla, six outer labial sensilla, four cephalic sensilla and two amphids. Each sensillum consists of ciliated sensory neurons ending in a channel enclosed by two non-neuronal cells, the sheath and socket cells. The amphidial channel opens to the outside as does that of the inner labial sensilla so that these probably contain chemoreceptive neurons. The endings of the other sensilla are embedded in the cuticle and may be mechanoreceptive. The cell bodies of all neurons lie near the nerve ring and their axons project into the ring or into ventral ganglia. One of the ciliated sensory neurons in each of the six inner labial sensilla makes direct chemical synapses onto a muscle making these sensory-motor neurons. The anatomy of four isogenic animals was compared in detail and found to be largely invariant. The anatomy of juveniles is nearly identical to that of the adult, but males have four additional neuron processes. ------------------- Key: 395 Medline: Authors: Ware RW;Clark D;Crossland K;Russell RL Title: The nerve ring of the nematode C. elegans: Sensory input and motor output. Citation: Journal of Comparative Neurology 162: 71-110 1975 Type: ARTICLE Genes: Abstract: The general organization and structure of the nerve ring, the main mass of central nervous system neuropil, in the small soil nematode Caenorhabditis elegans is described. The nerve ring receives sensory input from the anterior tip of the animal by means of six nerve bundles, all nerve fibers of which have centrally located cell bodies. The anterior sensory structures are classically divided into two types, papillary and amphidial, and are assumed responsible for mechano- and chemoreception, respectively. Papillary fibers enter directly into the nerve ring, whereas amphidial fibers enter the ventral ganglion, a posterior extension of the nerve ring, in a circuitous manner which is not discussed in detail. Of those papillary fibers which project into the nerve ring neuropil, 22 end in easily characterized sensory structures whereas 14 terminate distally near sensory organs but have no function which can be deduced on the basis of comparative morphology. After entering the ring the fibers maintain their identity and do not anastamose with one another. Cell bodies of each papillary sensory neuron have been mapped around the nerve ring. The cephalic musculature is shown to consist of 32 muscle cells which form four longitudinal submedial groups of eight muscles each. Innervation of this musculature occurs wholly within the CNS by means of processes of the muscle cells which are sent centrally. The anterior 16 cephalic muscle cells are innervated by the ring only, in well delimited regions termed muscle plates. The posterior 16 are dually innervated by means of processes sent both to the nerve ring plates and to their nearest medial longitudinal nerve cord. The nerve ring neuropil is characterized as having fibers containing one of four morphologically distinct vesicle types. Gap junction contacts are observed within the main neuropil involving one of these fiber types and within the muscle plate regions among muscle processes, which do not contain vesicles. An evolutionarily primitive sensory-motor synapse within the nerve ring is described from an identified sensory neuron onto an identifed cephalic muscle cell process. Comparisons are made with the nervous system of Ascaris lumbricoides, the only other nematode to be extensively studied, to illustrate the ------------------- Key: 397 Medline: 79032165 Authors: Waterston RH;Brenner S Title: A suppressor mutation in the nematode acting on specific alleles of many genes. Citation: Nature 275: 715-719 1978 Type: ARTICLE Genes: cat-1 dpy-18 nuc-1 sup-5 Abstract: A suppressor mutation has been isolated in Caenorhabditis elegans through reversion analysis of a muscle-defective mutant. The suppressor mutation acts on specific alleles of at least six genes and in one case we have been able to show that it partially restores functional gene product to a mutant otherwise lacking that product. These and other features of the suppressor suggest that it acts at some step in information transfer, perhaps through mechanisms similar to those described previously in microorganisms. ------------------- Key: 398 Medline: 75116749 Authors: Waterston RH;Epstein HF;Brenner S Title: Paramyosin of C. elegans. Citation: Journal of Molecular Biology 90: 285-290 1974 Type: ARTICLE Genes: Abstract: Paramyosin has been isolated from the nematode, Caenorhabditis elegans. Its identity has been established by a variety of criteria, including purification, molecular weight, immunological cross reactivity with known paramyosin and formation of characteristic paracrystals. The presence of paramyosin in both pharyngeal and body-wall musculature was shown by a technique that allows analysis by sodim dodecyl sulphate gels of the protein in a single worm. The possibility of defining the role of paramyosin in the structure and function of the invertebrate muscle through the isolation of mutants in this protein is ------------------- Key: 399 Medline: 78132937 Authors: Waterston RH;Fishpool RM;Brenner S Title: Mutants affecting paramyosin in C. elegans. Citation: Journal of Molecular Biology 117: 679-697 1977 Type: ARTICLE Genes: unc-15 Abstract: Four mutants of Caenorhabditis elegans with abnormal muscle structure are described which are alleles of a single locus unc-15. In one of the mutants, E1214, paramyosin is completely absent from both body-wall and pharyngeal musculature. In the other three mutants paramyosin is present but does not assemble into thick filaments. Instead paramyosin paracrystals are formed in the body-wall muscle cells. Myosin filaments lacking paramyosin cores are present in all four mutants, but these filaments fail to integrate stably into the myofilament lattice. One mutant is temperature-sensitive; all four are semi-dominant in their effect on muscle structure. The hypothesis that unc-15 is the structural gene for paramyosin is discussed. ------------------- Key: 400 Medline: 74297483 Authors: Watson JE;Pinnock CB;Stokstad ELR;Hieb WF Title: A nephelometer for measurement of nematode populations. Citation: Analytical Biochemistry 60: 267-271 1974 Type: ARTICLE Genes: Abstract: A nephelometer for measuring nematode populations is described in which a standard 18 mm culture tube is illuminated from below, and four selenium photocells are placed radially at 90 degrees about the tube. This design minimizes fluctuations in readings due to movement of the nematodes at low population densities. ------------------- Key: 401 Medline: 78114101 Authors: White JG;Albertson DG;Anness MAR Title: Connectivity changes in a class of motoneurone during the development of a nematode. Citation: Nature 271: 764-766 1978 Type: ARTICLE Genes: lin-6 Abstract: The ventral nerve cord of the nematode Caenorhabditis elegans contains a linear array of motoneurones which innervate the body muscles that mediate locomotion. The adult ventral cord has about three times as many cells as that of the first stage larva. The development events that generate the adult complement of cells occur in a period preceding the first larval moult. During this period we find that a class of pre-existing, juvenile motoneurones changes its pattern of connectivity. Neuromuscular junctions are removed from ventral muscles and are reformed onto dorsal muscles. Similarly the dendritic input to these neurones changes over from the dorsal to the ventral side. The structure and connectivity of ventral cord motoneurones in adult hermaphrodites has been determined by serial section reconstruction of electron micrographs. The salient features of the structure are summarised below: ------------------- Key: 402 Medline: 76269914 Authors: White JG;Southgate E;Thomson JN;Brenner S Title: The structure of the ventral nerve cord of C. elegans. Citation: Philosophical Transactions of the Royal Society of London 275B: 327-348 1976 Type: ARTICLE Genes: Abstract: The nervous system of Caenorhabditis elegans is arranged as a series of fibre bundles which run along internal hypodermal ridges. Most of the sensory integration takes place in a ring of nerve fibres which is wrapped round the pharynx in the head. The body muscles in the head are innervated by motor neurones in this nerve ring while those in the lower part of the body are innervated by a set of motor neurones in a longitudinal fibre bundle which joins the nerve ring, the ventral cord. These motor neurones can be put into five classes on the basis of their morphology and synaptic input. At any one point along the cord only one member from each class has neuromuscular junctions. Members of a given class are arranged in a regular linear sequence in the cord and have non-overlapping fields of motor synaptic activity, the transition between fields of adjacent neurones being sharp and well defined. Members of a given class form gap junctions with neighbouring members of the same class but never to motor neurones of another class. Three of the motor neurone classes receive their synaptic input from a set of interneurones coming from the nerve ring. These interneurones can in turn be grouped into four classes and each of the three motor neurone classes receives its synaptic input from a unique combination of interneurone classes. The possible developmental and functional significance of these ------------------- Key: 403 Medline: Authors: Wilson PAG Title: Nematode growth patterns and the moulting cycle: the population growth profile. Citation: Journal of Zoology 179: 135-151 1976 Type: ARTICLE Genes: Abstract: Population growth profiles of Caenorhabditis elegans and Panagrellus redivivus constructed from length frequencies have a number of steps in them coinciding with the number of extrauterine moults. Each step has a constant size in relationship with that of one of the midmoults measured directly. The profiles could only have the shape they do if there are corresponding steps in the true growth curve of individual worms: the fact that previous workers have been unable to detect these steps being due to the limitations of techniques available for the study of synchronous and individual growth curves. Nevertheless, a synchronous system with Trichostrongylus retortaeformis gives qualitative support to the findings from population profiles. The population growth profile is a new tool in the study of environmental effects on moulting, though there are theoretical reasons why the true growth curve cannot be derived from it. Abandonment of the "continuous growth" model for post-embryonic development simplifies the framing of hypotheses to explain ecdysis in nematodes. ------------------- Key: 404 Medline: 78220824 Authors: Wolf N;Hirsh D;McIntosh JR Title: Spermatogenesis in males of the free-living nematode, C. elegans. Citation: Journal of Ultrastructure Research 63: 155-169 1978 Type: ARTICLE Genes: Abstract: We have studied the morphology of spermatogenesis in the free-living nematode Caenorhabditis elegans with the light and electron microscopes. The gonad of the adult male is a single, reflexed cylindrical structure containing all stages of spermatogenesis arranged in a single wave of development. The primary spermatocytes are at the end of the gonad most distal from its opening into the cloaca. In this region, the cells are syncytial, and there is a central core containing cytoplasm common to all the neighboring cells, an organization reminiscent of the ovary in the hermaphrodite. Moving towards the cloaca one encounters the stages of meiotic prophase. At diplotene and diakinesis the cells contain many Golgi complexes. Some of these Golgi complexes are associated with an urn-shaped vesicle with a dark amorphous collar about its neck. Other Golgi complexes are seen next to aggregates of microfilaments. These "fibrous bodies" become enveloped with a flattened vesicle that forms a boundary two membranes thick. After these two structures have grown in size, their membranes fuse to form a composite structure. The membranes at the site of fusion then develop dark-staining thickenings as they fold into convoluted sacs and tubes. At about this time, the cells go through the two meiotic divisions. At telophase II the composite structures and fibrous bodies cluster at the spindle poles and cleavage furrows not only separate the daughter cells, but they also slough off a substantial volume of cytoplasm. In the resulting spermatid the nucleus condenses to form the small mass of dark-staining chromatin characteristic of sperm. The microfilaments of the fibrous bodies now disappear while the membranes of the composite structures continue to fold. The texture of the cytoplasm becomes more dense and now contains numerous slender, wavy tubular elements. A part of each composite structure now fuses with the plasma membrane of the sperm to make an almost spherical invagination of extracellular space partially filled by the tortuous bits of membrane-bound cytoplasm ------------------- Key: 405 Medline: Authors: Wood WB Title: Summary of workshop on nematodes. Citation: "Molecular Approaches to Eucaryotic Genetic Systems" ICN-UCLA Symposia on Molecular & Cellular Biology, Volume 8. Wilcox G, Abelson J and Fox CF (eds), Academic Press, NY. 8: 357-358 1977 Type: NEWS Genes: Abstract: The workshop on nematodes presented current research from four laboratories on the development and physiology of C. elegans. ------------------- Key: 406 Medline: Authors: Wright DJ;Awan FA Title: Acetylcholinesterase activity in the region of the nematode nerve ring: Improved histochemical specificity using ultrasonic pretreatment. Citation: Nematologica 22: 326-331 1976 Type: ARTICLE Genes: Abstract: Panagrellus redivivus, Caenorhabditis elegans, Prionchulus punctatus, Aphelenchus avenae and Ditylenchus dipsaci were stained for cholinesterase activity using the 'direct-colouring' thiocholine method. Enzyme activity was concentrated in the region of the nerve ring in each species. Ultrasonic pretreatment of intact or cut nematodes was found to greatly improve the staining consistency at the nerve ring, and using two substrates (acetylthiocholine and butyrylthiocholine) and three inhibitors (eserine, BW 284C51, and iso-OMPA) this staining was found to be due to acetlycholinesterase (E.C. 3.1.1.7) ------------------- Key: 407 Medline: Authors: Yarwood EA;Hansen EL Title: Dauer larvae of Caenorhabditis briggsae in axenic culture. Citation: Journal of Nematology 1: 184-189 1969 Type: ARTICLE Genes: Abstract: The free-living hermaphroditic nematode, Caenorhabditis briggsae, enters a dauer stage under certain conditions in axenic culture. Dauer larvae differ from directly-developing third-stage larvae in internal structure, size at time of second molt, morphology of second and third cuticles, separation zone of cuticular caps, and survival at 4C and 37C, temperatures fatal to other stages. Males, which occur rarely in liquid medium, may mature under conditions which cause most of the hermaphrodites to go into the dauer stage, resulting in a culture with increased male-to-hermaphrodite ratio. ------------------- Key: 409 Medline: Authors: Zuckerman BM Title: The effects of procaine on aging and development of a nematode. Citation: "Theoretical Aspects of Aging." Rockstein M (ed), Academic Press, NY. : 177-186 1974 Type: REVIEW Genes: Abstract: The free-living nematode, Caenorhaditis briggsae, is being used in our laboratory to study the complex events associated with biological aging. Our approach to this problem involved first the defining of parameters characterizing senescence in this animal, and then evaluating the effects on these aging signs of a drug reported to have a modifying effect on some aspects of the aging processes. Reference in this report to this preparation, Gerovital H3 (2% procaine hydrochloride, 0.16% benzoic acid, 0.14% potassium metabisulfite, buffered to pH 3.3 from Rom-Amer Pharmaceuticals, Ltd., Beverly Hills, California) is by its active ingredient, "Procaine". ------------------- Key: 410 Medline: Authors: Zuckerman BM Title: Nematodes as models for aging studies. Citation: "The Organization of Nematodes." Croll NA (ed), Academic Press, NY. : 211-241 1976 Type: REVIEW Genes: Abstract: ------------------- Key: 411 Medline: 78168994 Authors: Zuckerman BM;Barrett KA Title: Effects of P-chlorophenoxy acetic acid and dimethylaminoethanol on the nematode C. briggsae. Citation: Experimental Aging Research 4: 133-139 1978 Type: ARTICLE Genes: Abstract: Concentrations of 6.8 mM DMAe did not retard age pigment accumulation in Caenorhabditis briggsae. However, when the nematodes were exposed to 6.8 mM PCA + 6.8 mM DMAE combined, the accumulation of age pigment was significantly retarded. A combination of 3.4 mM DMAE + 3.4 mM PCA had no effect on age pigment. It is concluded from this study that PCA and DMAE act in concert to produce the observed effect on age pigment. In respect to this parameter neither molecule was effective alone. The results indicate that the effect of centrophenoxine on age pigment might be enhanced by retarding the hydrolysis of centrophenoxine. The accumulation of electron dense aggregates, thought to be aggregates of cross-linked molecules, was reduced by 6.8 PCA + 6.8 DMAE. It is suggested that centrophenoxine be tested for its ability to remove random, unwanted cross-linkages in higher animals. ------------------- Key: 412 Medline: Authors: Zuckerman BM;Castillo JM;Deubert KH;Gunner HB Title: Studies on a growth supplement for C. briggsae from freeze-dried bacteria. Citation: Nematologica 15: 543-549 1969 Type: ARTICLE Genes: Abstract: Freeze-dried bacteria isolated from Panagrellus redivivus, contained a growth supplement that initially supported rapid growth and reproduction of Caenorhabditis briggsae. However, after four serial subcultures, the nematodes became sluggish and eventually died. Evidence is given that C. briggsae utilizes the bacterial cell as a food source, thereby showing that the bacterium-nematode relation is not one of mutualism. ------------------- Key: 415 Medline: Authors: Zuckerman BM;Himmelhoch S;Kisiel M Title: Fine structure changes in the cuticle of adult C. briggsae with age. Citation: Nematologica 19: 109-112 1973 Type: ARTICLE Genes: Abstract: The cuticle of young, adult Caenorhabditis briggsae contains seven layers. In old nematodes fine structure changes related to aging were observed in two layers. The outer osmiophilic membrane became more defined and in a few cases separated from the external cortical layer. Also, an electron-dense material and electron-dense balls occurred within the fluid-filled layer. The possible significance of these observations is discussed. ------------------- Key: 417 Medline: Authors: Zuckerman BM;Himmelhoch S;Nelson B;Epstein J;Kisiel M Title: Aging in C. briggsae. Citation: Nematologica 17: 478-487 1971 Type: REVIEW Genes: Abstract: Caenorhabditis briggsae was used as a model to study aging of a metazoan under gnotobiotic conditions. At higher temperatures nematodes were shorter-lived and had a shorter generation time. Nematodes moved more slowly as they aged. Physiologic aging was marked by a decreased ability to withstand osmotic stress, a possible increase in the body's internal solute concentration, and increased sensitivity to formaldehyde. These results suggest that the ability to osmoregulate and the permeability of the body wall are altered during senescence. The interchordal hypodermis, as well as the chordal hypodermis, contained fairly abundant structures having biosynthetic activity. During aging mitochondria of the hypodermis degenerated, some areas of the thin hypodermal band thickened and lysosome-like bodies formed in the interchordal hypodermis. Changes in osmoregulatory and excretory mechanisms are probably associated with deterioration of hypodermis organelles. ------------------- Key: 419 Medline: 79191599 Authors: Zuckerman BM;Kahane I;Himmelhoch S Title: C. briggsae and C. elegans: Partial characterization of cuticle surface carbohydrates. Citation: Experimental Parasitology 47: 419-424 1979 Type: ARTICLE Genes: Abstract: The presence of galactose, glucose, mannose, and N-acetylglucosamine on the exposed surface of the nematodes Caenorhabditis briggsae and C. elegans was indicated by specific binding of three iodinated plant lectins. Proteolysis experiments suggested the absence of digestible glycoproteins on the exposed surfaces of the two nematode species. High resolution micrographs of cuticle surface preparations labeled with cationized ferritin indicated that the negative charge-bearing molecules are more densely packed on the nematode surface than on animal plasma membranes. ------------------- Key: 420 Medline: Authors: Zuckerman BM;Nelson B;Kisiel M Title: Specific gravity increase of C. briggsae with age. Citation: Journal of Nematology 4: 261-262 1972 Type: ARTICLE Genes: Abstract: The specific gravity of old Caenorhabditis briggsae was shown to be greater than that of young nematodes. The possible explanations for this age-associated change are discussed. ------------------- Key: 422 Medline: 79136487 Authors: Cortese R;Melton D;Tranquilla T;Smith JD Title: Cloning of nematode tRNA genes and their expression in the frog oocyte. Citation: Nucleic Acids Research 5: 4593-4611 1978 Type: ARTICLE Genes: Abstract: Transfer RNA genes of the nematode Caenorhabditis elegans have been cloned in E. coli using the plasmid Col E1 as vector. The tRNAs coded by 3 hybrid plasmids were purified by hybridisation of labelled nematode tRNA with the plasmid DNAs. Each plasmid appears to code for a single distinct tRNA species. The expression of the cloned DNAs was analysed in vivo by injection into nuclei of Xenopus laevis oocytes. Evidence is presented which suggests that these nematode tRNA genes are accurately transcribed and processed in frog oocytes. Analysis of one hybrid plasmid shows that a 300 base pair DNA fragment contains both the structural gene and those regions required for its transcription in vivo. The results show that cloned eukaryotic DNAs from a heterologous source can be tested for functional gene activity in X. laevis oocytes. ------------------- Key: 424 Medline: Authors: Cassada RC Title: The dauer larva of C. elegans: A specific developmental arrest, inducible environmentally and genetically. Citation: "Developmental Biology: Pattern Formation and Gene Regulation." McMahon DM and Fox CF (eds), WA Benjamin. : 539-547 1975 Type: ARTICLE Genes: Abstract: In the development of the nematode, Caenorhabditis elegans, a recognizable, non-growing stage, the dauerlarva, may arise. It is formed in response to adverse environmental conditions including starvation by an arrest just before the second of four cuticle molts. A quantitative assay for dauerlarva based on their resistance to sodium dodecyl sulfate has been developed. Resistance requires both non-feeding and an especially impermeable cuticle, containing a paracrystalline proteinaceous sheet 1600-1800 A thick. Quantitave, synchronous recovery to normal development can be induced by transfer to fresh medium with excess food; there is a soluble, heat-stable arrest factor in starved cultures. Using the resistance property, mutants have been selected that conditionally (temperature-sensitivity) enter the dauerlarva state even when food is abundant. ------------------- Key: 425 Medline: 80090059 Authors: Melton DA;Cortese R Title: Transcription of cloned tRNA genes and the nuclear partitioning of a tRNA precursor. Citation: Cell 18: 1165-1172 1979 Type: ARTICLE Genes: Abstract: The transcription of transfer RNA genes (tDNAs) and processing of the transcripts have been studied by injecting cloned tDNAs into Xenopus oocyte nuclei. Three main conclusions can be drawn. First, eucaryotic nuclear tRNA genes, but neither procaryotic nor mitochondrial tRNA genes, are expressed in injected oocytes. While both nematode and yeast tDNAs direct the synthesis of authentic tRNAs, neither E. coli tDNA nor human mitochondrial tDNAs support the synthesis of defined tRNAs when injected into oocytes. Second, competition experiments with co-injected 5S genes and inhibition experiments with a-amanitin show that injected tDNAs are transcribed by RNA polymerase III. Third, oocytes injected with a nematode tDNA synthesize a tRNA precursor which is processed post-transcriptionally by removal of a 5' leader sequence. This precursor is found exclusively in the nucleus and is processed in the nucleus before the mature tRNA enters the cytoplasm. ------------------- Key: 426 Medline: 80180014 Authors: Wood WB;Hecht R;Carr S;Vanderslice R;Wolf N;Hirsh D Title: Parental effects and phenotypic characterization of mutations that affect early development in C. elegans. Citation: Developmental Biology 74: 446-469 1980 Type: ARTICLE Genes: emb-7 emb-9 zyg-1 zyg-2 zyg-3 zyg-5 zyg-7 zyg-8 zyg-9 zyg-10 zyg-11 zyg-12 zyg-13 Abstract: Genetic tests for parental effects were performed on 24 temperature-sensitive embryonic-lethal mutants of the nematode Caenorhabditis elegans. For 21 of these mutants, maternal expression of the wild-type allele is sufficient for embryonic survival, regardless of the embryo's genotype. For 11 of these 21 mutants, maternal expression of the wild-type allele is necessary for embryonic survival (strict maternals). For the remaining 10, either maternal or embryonic expression is sufficient for survival (partial maternals). One mutant shows a paternal effect; that is, a wild-type extragenic sperm function appears to rescue homozygous mutant embryos. Similar parental-effect tests were performed on 11 larval-lethal mutants. In 4 mutants, 1 of which blocks as late as the second larval stage after hatching, maternal contributions still can rescue mutant larvae. The remaining 3 embryonic lethals and 8 larval lethals show no parental effects; that is, zygotic expression of the wild-type allele is necessary and sufficient for embryonic survival. Temperature-shift experiments on embryonic-lethal embryos showed that all but 1 of the strict maternal mutants are temperature sensitive only before gastrulation. One of the partial maternal mutants is temperature sensitive prior to gastrulation, suggesting that some zygotic genes can function early in embryogenesis. At the nonpermissive temperature, 7 of the strict maternal mutants either show cleavage abnormalities in early divisions or stop cleavage at less than 100 cells, or both. ------------------- Key: 427 Medline: 81261881 Authors: Rose AM;Baillie DL Title: Genetic organization of the region around unc-15(I), a gene affecting paramyosin in C. elegans. Citation: Genetics 96: 639-648 1980 Type: ARTICLE Genes: dpy-14 dpy-24 let-75 let-77 let-78 let-79 let-80 let-81 let-82 let-83 let-84 let-85 let-86 let-87 let-88 let-89 let-90 mec-8 unc-13 unc-15 unc-29 unc-37 unc-87 Abstract: In the nematode Caenorhabditis elegans mutants in the gene unc-15 (I) affect the muscle protein paramyosin (Waterston, Fishpool and Brenner 1977). We have characterized 20 ethyl methanesulfonate-induced mutations in essential genes closely linked to unc-15. These lethals defined 16 new complementation groups. In the 0.65 map-unit interval around unc-15 defined by dpy-14 and unc-56, seven newly identified genes have been mapped relative to five existing genes. At present, the average distance between genes in this region is approximately 0.05 map units. Two genes, unc-15 and unc-13, are only 0.025 map units apart. Partial fine-structures maps of alleles of these two genes have been constructed. This analysis of unc-15 and genes adjacent to it is the first in a series of genetic and biochemical studies directed towards understanding the control of unc-15 expression. ------------------- Key: 429 Medline: Authors: Kampfe L Title: The consumption of oxygen by nematodes as a characteristic of zootic activity. Citation: Pedobiologica 18: 355-365 1978 Type: ARTICLE Genes: Abstract: The features of respiration in soil-inhabiting nematodes are discussed and some autecological findings on the respiratory rate under normal conditions and those with deviating O2-partial pressure are compiled. Lack of oxygen leads to different reactions by the inhabitants of variable hatitats. They also show a different utilization of their reserve substances. The respiratory quotient differs in the species under consideration, it may change during starvation. Considering the consumption of oxygen the investigations known on the bioenergetic role of nematodes in soil are discussed. Conversions show clues to the catabolism of protein by nematodes per hectare and per year. The values fluctuate between 43 and 250 kg protein ha-1 year-1. The difficulties in these estimations are pointed out. Finally a reference is made to the fact that the respiratory efficiency of nematodes is influenced by the presence of pesticides in the medium. The effects of the new generation of systemic nematicides are particularly interesting because of their relatively small influence on the free-living soil nematodes which is the consequence of the relatively slight immediate efficacy. Herbicides do not seem to be without any effect on the soil nematode ------------------- Key: 430 Medline: Authors: Brun J;Abdulkader N;Abirached M;Beguet B;Gibert M-A;Mounier N;Starck J;Bosch C Title: Controle genetique de la gametogenese et de la differenciation ovocytaire chez C. elegans, souche Citation: Ann. Rep. Univ. CB/Lyon Fr : 25-43 1978 Type: ARTICLE Genes: Abstract: ------------------- Key: 431 Medline: Authors: Hansen EL;Yarwood EA;Nicholas WL;Sayre FW Title: Differential nutritional requirements for reproduction of two strains of Caenorhabditis elegans in axenic culture. Citation: Nematologica 5: 27-31 1959 Type: ARTICLE Genes: Abstract: Caenorhabditis elegans (Maupas) has been maintained in axenic culture for more than three years. Two separate isolations, one in France and one in England, have been made and are here designated as Bergerac strain and Bristol strain respectively. Although morphologically similar and successfully crossed by Nigon, the two strains have shown different cultural requirements. This difference was first observed in 1958, using a supplemented chemically defined medium, and has now been investigated in a wider range of media. ------------------- Key: 432 Medline: 71034132 Authors: Hansen EL;Perez-Mendez G Title: Large scale preparation of liver growth factor for cultivation of nematodes. Citation: Proc. Society for Experimental Biology & Medicine 135: 487-489 1970 Type: ARTICLE Genes: Abstract: Cultivation of metazoa under bacteria-free conditions is valuable for biochemical and nutritional studies and avoids the complexity introduced by associated organisms. For such studies the nematode has particular advantages. Investigation of the nutritional requirements of the free-living nematode Caenorhabditis briggsae led to the development of a chemically defined medium which required addition of a low level of an organic supplement to obtain continued reproduction. One very effective supplement is a partially purified protein designated growth factor (GF). This has been used in the culture of free-living nematodes and parasitic helminths. GF was originally prepared by a slow, laborious, stepwise elution from hydroxylapatite columns. In the present paper a rapid, efficient "batch" technique is described. Using this new method, batches yielding more than 2 g of GF have been prepared easily in a day. ------------------- Key: 433 Medline: Authors: Hirsh D Title: Temperature sensitive maternal effect mutants of early development in C. elegans. Citation: "Determinants of Spatial Organization" Meeting, Society for Developmental Biology, Madison, WI June 1978. Subtelny S and Konigsberg IR (eds), Academic Press, NY. : 149-166 1979 Type: REVIEW Genes: emb-7 emb-9 zyg-1 zyg-2 zyg-3 zyg-7 zyg-8 zyg-9 zyg-10 zyg-12 Abstract: We have isolated temperature sensitive maternal effect mutants in the free-living nematode Caenorhabditis elegans. We use C. elegans for several basic reasons. It is easy to culture in the laboratory and it has a rapid life cycle. The genetics of C. elegans have been elucidated by Brenner and more recently have been refined by the lethal analysis of Herman et. al. Both embryonic and postembryonic development can be observed directly and conveniently on the living worm with Nomarski differential interference optics because egg shell and worm cuticle are transparent. The precise embryonic cell lineages of C. elegans are known from fertilization to the 200 blastomere stage. All of the postembryonic somatic cell lineages are precisely known. It ... ------------------- Key: 434 Medline: Authors: Kunz P;Klingler J Title: A method for direct or microscopic observation and photography of nematode tracks during orientation behaviour studies. Citation: Nematologica 22: 477-479 1976 Type: ARTICLE Genes: Abstract: Considerable progress in the study of orientation behaviour of nematodes was achieved as soon as their tracks could be made visible on agar surfaces from which the free water had evaporated.... ------------------- Key: 435 Medline: Authors: Laskey R;Lawrence P;De Robertis E Title: Genes in development. Citation: Nature 270: 477-478 1977 Type: NEWS Genes: Abstract: Participants in two days of talks held at the Accademia Lincei in Rome-the oldest scientific foundatin in the modern world, tried to tackle the ancient problem of how eggs plus genes produce animals. It was symptomatic of the renewed interest in Drosophila that the whole of the first day was devoted to that fly... ------------------- Key: 436 Medline: Authors: MacLeod AR;Karn J;Waterston RH;Brenner S Title: The unc-54 myosin heavy chain gene of C. elegans: A model system for the study of genetic suppression in higher eukaryotes. Citation: "Nonsense Mutations and tRNA Suppressors" Proc. EMBO Lab Course & Aarhus Univ. 50 Yr. Anniv. Symp. July 1978. Celis CE and Smith JD (eds), Academic Press, London. : 301-312 1979 Type: ARTICLE Genes: unc-54 Abstract: The small free living soil nematode Caenorhabditis elegans, has been the subject of genetical and other studies in this laboratory for several years. Mutants have been isolated in many genes affecting its morphology and behaviour and a considerable amount is now known about its cellular anatomy and development. A subset of mutants with defective movement have severe alterations in the structure of body wall muscle cells. There are 95 muscle cells disposed in four quadrants which run the length of the animal beneath the cuticle. The musculature is obliquely striated and the sarcomeres are oriented parallel to the long axis of the animal. Disruption of the band structure can easily be detected in the living animal by polarized light microscopy and the defects can be more carefully analysed by electron microscopy. Two of the ten genes with altered muscle phenotypes have been shown to specify major structural proteins of muscle; unc-54 codes for a major heavy chain of mysoin, while unc-15 codes for paramyosin, the core protein of the thick filaments. As work with these genes developed, it became evident that it might be possible to use them as models for studying gene-protein relationships in a multicellular higher organism. This notion has been reinforced by the isolation of a large number of suppressors in the organism, some of which suppress specific alleles of the myosin and para-myosin genes. Although the molecular mechanism of these suppressors are unknown, it will be seen that their detailed study can now ------------------- Key: 437 Medline: 80046643 Authors: Popham JD;Webster JM Title: Cadmium toxicity in the free living nematode C. elegans. Citation: Environmental Research 20: 183-191 1979 Type: ARTICLE Genes: Abstract: The effect of cadmium on the fecundity, growth, and fine structure of the free-living nematode Caenorhabditis elegans was studied. High concentrations of cadmium significantly decreased the fecundity and growth of these organisms. Electron microscopy showed that cadmium modifies the structure of the mitochondria in the esophagus and intestine, causes the formation of inclusion bodies in the nucleus of esophageal cells, and alters the morphology of cytosomes in the intestinal cells. The results suggest that the decreased fecundity and growth of cadmium-exposed C. elegans may be due to cadmium interfering with nutrient uptake or assimilation or both. ------------------- Key: 438 Medline: 79010541 Authors: Smith SJ Title: The structural gene for myosin, a closer look. Citation: Nature 272: 495-496 1978 Type: REVIEW Genes: unc-54 Abstract: The humble soild nematode Caenorhabditis elegans has proved a useful tool for the extension of the study of gene-protein relationships from prokaryotic to eukaryotic organisms. A variety of uncoordinated (unc) mutants can be isolated by their behavioral characteristics, and electron micrographs show that such mutations are associated with disorganisation of muscle structure. One such mutant of the unc-54 gene (e675) has a normal amount of myosin but the number of thick filaments (myosin-containing ------------------- Key: 439 Medline: Authors: Sulston JE;Hodgkin J Title: A diet of worms. Citation: Nature 279: 758-759 1979 Type: NEWS Genes: sup-5 sup-7 unc-15 unc-22 unc-54 Abstract: Five years ago Brenner published an extensive genetic characterisation of the small free-living nematode Caenorhabditis elegans. Largely as a result of his pioneering work, this organism has become the subject of many different lines of research. Last May more than 120 researchers met at Cold Spring Harbor to discuss recent findings in C. elegans biology. ------------------- Key: 440 Medline: Authors: von Ehrenstein G;Schierenberg E;Miwa J Title: Cell lineages of wild type and temperature sensitive embryonic arrest mutants of C. elegans. Citation: "Cell Lineage, Stem Cells and Cell Determinations." Le Douarin N (ed), Elsevier, NY. : 49-58 1979 Type: REVIEW Genes: emb-1 emb-2 emb-3 emb-4 emb-5 emb-6 emb-7 emb-8 emb-9 Abstract: Caenorhabditis elegans, a free-living nematode, is the subject of intensive genetic and developmental studies. Embryogenesis in C. elegans, like other nematodes, is strictly determinate and virtually invariant among individuals. The newly hatched juvenile has only about 550 cells arranged quite predictably. Postembryonic development is also quite regular and the number of nongonadal cells increases to only about 810 in the adult hermaphrodite. Here we will summarize results of embryonic cell lineage studies in our laboratory including the wild type and temperature-sensitive embryonic arrest mutants. We will also compare the developmental mechanisms of C. elegans to those of higher animals, and speculate about the possible role of histones in the timing of cell divisions in embryogenesis. ------------------- Key: 442 Medline: 80145768 Authors: Zengel JM;Epstein HF Title: Mutants altering coordinate synthesis of specific myosins during nematode muscle development. Citation: Proceedings of the National Academy of Sciences USA 77: 852-856 1980 Type: ARTICLE Genes: unc-52 unc-54 Abstract: Mutations in the unc-52 gene on linkage group II retard the construction of body-wall muscle sarcomeres during larval development in the nematode Caenorhabditis elegans. Unc-52 mutants show decreased accumulation of myosin heavy chains relative to other polypeptides during larval development, correlating with the structural retardation. Pulse radiolabeling experiments show that decreased synthesis of specific body-wall myosin heavy chains that are encoded by the unc-54 gene on linkage group I is responsible for the defective myosin accumulation. In the wild type, a constant ratio of the synthesis of the unc-54-coded myosin B to myosin A, about 2:1, is maintained during the larval stages in which the synthesis of both myosins increases exponentially and rapid sarcomere growth and addition ensues. During the first 26 hr of larval development, before any structural or behavioral effects of unc-52 mutations are apparent, the synthesis of myosin heavy chains is also normal. By 38 hr, decreased synthesis of myosin B is detected in the unc-52 mutant SU200, when sarcomere growth slows considerably. The effects of mutations in the unc-52 locus are trans acting upon the synthesis of unc-54-coded myosin in a specific set of muscle cells during a defined period of larval development. ------------------- Key: 443 Medline: Authors: Herman RK;Horvitz HR;Riddle DL Title: The nematode Caenorhabditis elegans. Citation: Genetic Maps 1: 183-193 1980 Type: REVIEW Genes: Abstract: ------------------- Key: 444 Medline: Authors: Kimble J;Sulston J;White J Title: Regulative development in the post-embryonic lineages of C. elegans. Citation: "Cell Lineage, Stem Cells and Cell Determinations." Le Douarin N (ed), Elsevier, NY. : 59-68 1979 Type: ARTICLE Genes: lin-1 lin-2 mab-5 Abstract: In many invertebrates, cell lineages are apparently invariant from individual to individual. A given precursor cell follows a specific pattern of cell divisions, and its descendants follow fates that correspond to their respective positions in the lineage tree. Such a reproducible sequence of events provides an excellent system for studying how cells come to pursue particular fates during development. We have been interested to know if a cell's fate is specified by factors intrinsic to the cell, or if it is influenced by interactions between the cell and its environment. C. elegans is a particularly suitable organism for lineage studies because it is transparent throughout its life cycle, and because it consists of relatively few cells. Furthermore, C. elegans is a favorable organism for genetics, so the control of cell lineages can be studied by characterizing mutations that are defective in known lineages. The cell lineages of C. elegans have been described in the embryo to the 182 cell stage and after hatching. Approximately 50 cells resume divisions post-embyronically. In the somatic tissues, the number of cells (or nuclei) is increased from about 550 to about 950 in hermaphrodites and to about 1025 in males. These post-embryonic lineages are essentially invariant from worm to worm. As the worm enlarges and matures sexually, cells (or nuclei) are added to previously existing tissues (hypodermis, muscle, gut, and nervous system), and structures necessary for reproduction are elaborated. The latter include a gonad in both sexes, a vulva in hermaphrodites, and a tail specialized for copulation in males. This paper summarizes the results of laser ablation experiments performed on cells in the post-embryonic lineages of C. elegans. In particular, we focus on those experiments that demonstrate a regulative capacity in the cells of this predominantly invariant system. The post-embyronic lineages have the practical advantage for these studies that they can be traced by direct observation of the cells as they divide and assume their final fate. The regulative response, therefore, can be described at a level of cellular detail that has not been possible in other deletion studies. Our aim in performing these experiments is to infer how cells are controlled during normal development from their behavior in ------------------- Key: 445 Medline: Authors: White JG;Horvitz HR Title: Laser microbeam techniques in biological research. Citation: Electro-Optical Systems Design AUG: 23-24 1979 Type: ARTICLE Genes: Abstract: Microirradiation has been used as a tool for probing cells and subcellular organelles for the last fifty years. It is possible with good, high numerical aperture optics to obtain spot sizes of less than 1 um, which allows microsurgery to be performed at the cellular and subcellular levels. Valuable information has been obtained in this way concerning the functions of various cellular ------------------- Key: 446 Medline: Authors: Hirsh D;Emmons SW;Files JG;Klass MR Title: Stability of the C. elegans genome during development and evolution. Citation: "Eucaryotic Gene Regulation" ICN-UCLA Symposia on Molecular and Cellular Biology, Volume 14. Axel R, Maniatis T and Fox CF (eds), Academic Press, NY. 14: 205-218 1979 Type: ARTICLE Genes: Abstract: Recombinant DNA methods have been used to characterize the genome of Caenorhabditis elegans. To determine if DNA rearrangements occur during somatic differentiation, fifteen randomly cloned Bam H1 fragments of somatic DNA were hybridized to Bam H1 digests of germ and somatic DNA's on Southern filters. In this way, 50 fragments representing 0.3% of the genome were compared and no size differences were detected. The DNA's of two interbreeding strains of C. elegans were also compared to determine the degree of evolutionary divergence. Fifteen percent of the fragments differed between the two strains. However, no differences could be found between the rDNA's. The DNA's of C. elegans and C. briggsae were compared and very little homology could be detected even though these species are morphologically very similar. The fragments that differ in size between the two interbreeding strains are being genetically mapped. These experiments suggest that non-random segregation of chromosomes might be occurring in ------------------- Key: 447 Medline: 80132495 Authors: Nelson GA;Ward S Title: Vesicle fusion, pseudopod extension and amoeboid motility are induced in nematode spermatids by the ionophore monensin. Citation: Cell 19: 457-464 1980 Type: ARTICLE Genes: fer-2 him-5 Abstract: The sodium- and potassium-transporting ionophore monensin induces the maturation of Caenorhabditis elegans spermatids to spermatozoa in vitro. Rearrangement of cytoplasm, fusion of membranous organelles with the plasma membrane and growth of pseudopodia, all characteristic of in vivo spermiogenesis, occur within five minutes after exposure to monensin at concentrations of 0.1-1.0 micronM. This activation is dependent upon external Na+ and K+ ions but not Ca2+ ions. Monensin-activated spermatozoa have normal morphology and normal amoeboid motility. During activation spermatids twitch and rotate prior to pseudopod extension. Analysis of intermediates by transmission and scanning electron microscopy reveals that the sequence of morphogenetic events leading from the spherical spermatid to the polarized spermatozoan involves microvilli rearrangement and membranous organelle fusion, cytoplasmic polarization, then pseudopod extension. ------------------- Key: 448 Medline: 80202192 Authors: Schierenberg E;Miwa J;von Ehrenstein G Title: Cell lineages and developmental defects of temperature-sensitive embryonic arrest mutants in C. elegans. Citation: Developmental Biology 76: 141-159 1980 Type: ARTICLE Genes: emb-1 emb-2 emb-3 emb-4 emb-5 emb-6 emb-7 emb-8 emb-9 Abstract: The cellular phenotypes of 11 temperature-sensitive mutants (emb-1 - emb-9) arresting in embryogenesis in Caenorhabditis elegans are described, including early embryonic cell lineages and developmental defects and the terminal phenotypes at the stage of arrest at the nonpermissive temperature (25C), as well as residual phenotypes at the permissive temperature (16C). By Nomarski microscopy of living embryos, the behavior of individual cells in mutant embryos is compared to that of the same cells in wild-type embryos. All mutants but one (emb-9) have visible defects before the 50-cell stage, even if they arrest much later. Cell proliferation continues in the absence of normal morphogenesis. The terminal phenotype of the late-arresting mutants looks grossly abnormal. The overall rate of cell division is faster than in the wild-type in two mutants, emb-3 and emb-5(hc67), and slower in five mutants, emb-2, emb-4, emb-5(hc61), emb-6 and emb-7. In five of these mutants, emb-3, emb-4, emb-5 (both alleles), and emb-7, the rate and the sequence of divisions of specific cell lines is altered. For all mutants with timing defects, maternal gene expression is at least sufficient. Gastrulation is abnormal in the two emb-5 mutants. A premature division of the intestine precursor cells occurs in close temporal coincidence with the defective execution stage (determined by temperature-shift experiments). The order of migration and division of the intestine precursor cells is reversed in gastrulation, and the cell pattern of the intestine primordium is abnormal. It seems possible that the timing error is responsible for the pattern defect. The cleavage behavior of emb-3 eggs indicates that germ line ------------------- Key: 449 Medline: 80202194 Authors: Miwa J;Schierenberg E;Miwa S;von Ehrenstein G Title: Genetics and mode of expression of temperature-sensitive mutations arresting embryonic development in C. elegans. Citation: Developmental Biology 76: 160-174 1980 Type: ARTICLE Genes: emb-1 emb-2 emb-3 emb-4 emb-5 emb-6 emb-7 emb-8 emb-9 Abstract: Eleven temperature-sensitive mutations causing arrest of embryogenesis in Caenorhabditis elegans have been mapped. The mutations define nine genes (emb-1 to emb-9) on four chromosomes. The functions of six genes seem to be required exclusively for embryogenesis. Mutants in these genes have no other detectable phenotype at the permissive (16C) or nonpermissive (25C) temperature. The function of the other three genes is also required for postembryonic development. As shown by progeny tests for parental effects, for seven genes, maternal gene expression is necessary and sufficient for normal embryogenesis; for one gene, emb-2, either maternal or zygotic expression is sufficient; for one gene, emb-9, zygotic expression is necessary and sufficient. The high proportion of emb genes with maternal expression is consistent with the model of intracellular preprogramming of the egg of C. elegans. Two developmental stages have been defined by temperature-shift experiments: (1) the normal execution stage indicating the time of execution of the normal event at the permissive temperature; (2) the defective execution stage indicating the time of the execution of an irreversible defect at the nonpermissive temperature. The classes of mutants defined by the progeny tests have corresponding stages, but the maternal necessary and sufficient class is subdivided into mutants executing during oogenesis or embryogenesis. ------------------- Key: 450 Medline: 80155174 Authors: Laufer JS;Bazzicalupo P;Wood WB Title: Segregation of developmental potential in early embryos of C. elegans. Citation: Cell 19: 569-577 1980 Type: ARTICLE Genes: Abstract: We have followed the appearance of differentiation markers in cleavage-inhibited and uninhibited early blastomeres of C. elegans and have compared the cleavage patterns of blastomeres in partial and complete embryos. The results indicate that at least some primary differentiation of embryonic cells is determined by internal factors that segregate in early cleavages, whereas patterns of cleavage are dictated by both internally segregating determinants and external cues. ------------------- Key: 451 Medline: Authors: Cryan WS Title: A method for axenizing large numbers of nematodes. Citation: Journal of Parasitology 49: 351-352 1963 Type: ARTICLE Genes: Abstract: Studies with parasitic and free-living nematodes in this laboratory have required large numbers of bacteria-free organisms. A procedure has been developed in which both larval and adult stages free themselves of debris by migrating through paper and glass beads, while the axenizing of concentrated antibiotics followed by prolonged holding in dilute antibiotics is achieved automatically without manipulation of the worms. ------------------- Key: 452 Medline: 81008630 Authors: Pong SS;Wang CC;Fritz LC Title: Studies on the mechanism of action of avermectin B1a: Stimulation of release of GABA from brain synaptosomes. Citation: Journal of Neurochemistry 34: 351-358 1980 Type: ARTICLE Genes: Abstract: Avermectin B1a, a novel macrocyclic lactone antiparasitic agent, causes a marked and sustained increase of gamma-aminobutyric acid from rat brain synaptosomes. A concentration of 8-10 um of avermectin B1a produced the maximal effect (310 +/- 30% of the control), while the half-maximal level was achieved at 2-3 um. The drug also stimulated gamma-aminobutyric acid release (251 +/- 11% of the basal level) from synaptosomes in calcium-free medium, which was 28 +/- 4% lower than that in the 1.8 mm-Ca2+ medium. The compound did not, however, affect the synaptosomal release of glutamate. At the lobster neuromuscular junction, avermectin B1a reduced the input resistance of muscle fibers in control Ringer's solution as well as in Ringer's solution in which Co2+ was substitited for Ca2+. This observation is in accord with the Ca2+ -independent stimulation of gamma-aminobutyric acid release seen with synaptosomes. A good correlation between antiparasitic activity and gamma-aminobutyric acid-releasing activity has been found among various derivatives of avermectin B1a, which suggests that the ability of the drug to release this neurotransmitter may be the basis of its antiparasitic action. ------------------- Key: 453 Medline: 80135165 Authors: Madl JE;Herman RK Title: Polyploids and sex determination in C. elegans. Citation: Genetics 93: 393-402 1979 Type: ARTICLE Genes: mnDp8 mnDp9 mnDp10 mnDp25 mnDp27 mnDp30 Abstract: Tetraploid stocks of Caenorhabditis elegans var. Bristol carrying autosomal and X-linked markers have been produced. Tetraploid hermaphrodites fall into two categories: those that give about 1% male self-progeny and those that give 25 to 40% male self-progeny. The former are basically 4A;4X--four sets of autosomes and four sex chromosomes--and the latter are 4A;3X. Males are 4A;2X. (Diploid hermaphrodites are 2A;2X; males are 2A;1X.) Triploids were produced by crossing tetraploid hermaphrodites and diploid males. Triploids of composition 3A;3X are hermaphrodites; 3A;2X animals are fertile males. Different X-chromosome duplications were added to a 3A;2X chromosome constitution to increase the X-to-autosome ratio. Based on the resulting sexual phenotypes, we conclude that there exists on the C. elegans X chromosome at least three (and perhaps many more) dose- sensitive sites that act cumulatively in determining sex. ------------------- Key: 455 Medline: Authors: Dusenbery DB Title: Responses of nematode C. elegans to controlled chemical stimulation. Citation: Journal of Comparative Physiology 136: 327-331 1980 Type: ARTICLE Genes: Abstract: A new method is described for studying the behavioral responses of nematodes to controlled chemical stimulation. The worm is held by the tail with a suction pipet. Behavior is recorded by an array of light sensors connected to a multichannel recorder. Several types of behavior can be detected in addition to the normal backward propagating waves of about 2 Hz that propel untethered worms forward. The most dramatic of these is the reversal bout, consisting of forward propagating waves of about 0.7 Hz, that propel untethered worms backward. The latter waves are easily distinguished from the former by the large amplitude motion caused by the fact that they contain a sharper bend at the tail. This technique was used to demonstrate that a purely temporal change in chemical stimulation can cause a large change in the probability of occurrence of a reversal bout. These altered probabilities adapt back to the basal level in about one minute. Increased probabilities adapt faster than decreased. Stronger stimulation causes slower adaptation. Since the reversal bout is associated with changes in direction of locomotion, these observations suggest that klinokinesis with adaptation plays a role in the movement of nematodes in chemical gradients. ------------------- Key: 456 Medline: Authors: Dusenbery DB Title: Appetitive response of the nematode C. elegans to oxygen. Citation: Journal of Comparative Physiology 136: 333-336 1980 Type: ARTICLE Genes: Abstract: Using a technique of recording the behavior of individual nematodes during exposure to various solutions, it was demonstrated that C. elegans made more reversal behaviors after transfer to solutions of lower oxygen tension than higher. The response was stronger after the first hour in the apparatus than initially. This change was not dependent on reduced oxygen availability during the initial period. Starvation is the most likely cause of this change. A variety of mutant strains of C. elegans that are defective in response to most known chemotactic stimuli, including two strains that have been shown to be severely abnormal in the ciliated endings of all sensory neurons of the worm's snout, all responded to changes in oxygen tension. This observation suggests that oxygen is sensed internally rather than by specialized receptor cells. ------------------- Key: 457 Medline: 80254943 Authors: Lewis JA Title: Commentary on the uses of small nematode worms. Citation: Neuroscience 5: 961-966 1980 Type: REVIEW Genes: ace-1 ace-2 unc-17 Abstract: Genetics in the study of less complicated organisms like bacteria has been a tremendously powerful way of recognizing individual elements hidden within a process, mutationally tagging them in ways easier to recognize by the biochemist. Identifying the elements used in the construction and function of nervous systems might be easier if genetics were readily applicable. The problem has been that the larger organisms with cells most suitable for impaling with microelectrodes and for obtaining isolated tissue for biochemical studies are the organisms most cumbersome genetically. Smaller, simpler organisms which can be raised rapidly and in the myriad quantity required for genetics usually lack the favorable attributes for study of the nervous system that come with size. One notable exception to this rule is the lowly, single-celled paramecium, which combines physiological accessibility with reasonably good genetics. But otherwise, for those interested in the genetics of multicellular nervous systems, it has been a matter of catch-as-catch-can. The attention of a few scientists has come to rest on the nematode, a worm not too many steps up the evolutionary ------------------- Key: 458 Medline: 80228804 Authors: Gossett LA;Hecht RM Title: A squash technique demonstrating embryonic nuclear cleavage of the nematode C. elegans. Citation: Journal of Histochemistry & Cytochemistry 28: 507-510 1980 Type: ARTICLE Genes: Abstract: A simple squash technique was developed which permits the observation of individual nuclei during embryogenesis of Caenorhabditis elegans. The technique consists of placing several two-cell stage embryos on a subbed slide in a droplet of M-9 salt buffer and incubating them in a sealed humidity chamber at 16.4 degrees C for increasing time intervals. The embryos are then squashed, fixed, and stained with Hoechst 33258. Rate of cleavage at 25.0 degrees C is 1.8 times faster than that at 16.4 degrees C. This yields superimposable growth curves upon correction for temperature. An initial lag in the rate of nuclear cleavage is followed by a burst of cell proliferation, which continues and then slows before 550-580 cells are produced at 4 to 5 hr at 25 degrees C. The squash size increases with cell number and reaches a maximum at about the 400-cell stage when early morphogenesis begins. The second half of embryogenesis is characterized by histogenesis in which the cells are held more tightly together, individual nuclei become less distinct, and the squash size decreases to a minimum as a small worm is ------------------- Key: 459 Medline: Authors: Abdulkader N;Brun JL Title: Caracterist genet et physiol de thermosensibilite du developpement embryon chz un mutant a letalite condition C. elegans/ Citation: Revue de Nematologie 3: 11-19 1980 Type: ARTICLE Genes: Abstract: Genetic physiological studies have been made on a 0.1 M E.M.S.-induced temperature-sensitive (ts) mutation affecting the embryonic development of the hermaphrodite nematode C. elegans, Bergerac strain. This mutation lts is Mendelian monofactorial recessive and autosomal. Using shift up and shift down experiments between permissive (18C) and non permissive (24C) temperatures, and brief heat shock at 24C, it can be seen that the mutant differs from the wild strain by a monophasic temperature-senstive lethal period situated between the 6th (+/- 1/2) and 18th (+/- 1/2) hours of the embryogenesis. During this period (TSP), 4 hours - exposure to the non-permissive temperature (24C) may be sufficient for a complete expression of the mutation, i.e. lethality of all the 1ts nematodes. However, two lethal phases may be observed, according to the TSP time at which embryos are subjected to 24C. In early TSP, the embryos fail to hatch, (= lethal phase I) while in late TSP the L1 normal larvae die before moulting ------------------- Key: 460 Medline: 80164135 Authors: Gandhi S;Santelli J;Mitchell DH;Stiles JW;Sanadi DR Title: A simple method for maintaining large aging populations of C. elegans. Citation: Mechanisms of Ageing & Development 12: 137-150 1980 Type: ARTICLE Genes: Abstract: This paper describes a technique capable of establishing and maintaining large, age-synchronous populations of the nematode Caenorhabditis elegans. The technique has three essential components: a rich chemical medium; a method for producing and harvesting mass quantities of eggs; and 5-fluorodeoxyuridine (FUdR), an inhibitor of DNA synthesis. A culture of worms is filtered through glass wool or a wire screen to isolate young larvae. Eggs laid by these worms after they mature are collected over a period of 4-6 hours and allowed to hatch. A low level of FUdR (25 microM) is added just before the larvae reach maturity. This timing is important to avoid developmental abnormalities. The adults lay eggs in the presence of FUdR but the eggs do not hatch, which maintains the synchrony of the culture. Many aging characteristics appear to be similar in treated and untreated worms, such as the time of cessation of egg production, the appearance of visible and behavioral age-related changes, and the mean lifespan. This system thus seems suitable for large-scale biochemical analysis of certain aspects of aging in C. elegans. ------------------- Key: 461 Medline: 80247148 Authors: Waterston RH;Thomson JN;Brenner S Title: Mutants with altered muscle structure in C. elegans. Citation: Developmental Biology 77: 271-302 1980 Type: ARTICLE Genes: unc-4 unc-11 unc-13 unc-15 unc-18 unc-22 unc-23 unc-26 unc-29 unc-31 unc-32 unc-33 unc-41 unc-42 unc-44 unc-45 unc-51 unc-52 unc-54 unc-60 unc-69 unc-78 unc-82 unc-87 unc-89 unc-90 Abstract: In the small nematode, Caenorhabditis elegans, mutants with disorganized myofilament lattice structure have been identified by polarized light microscopy. Genetic analysis places the mutations in 12 complementation groups which are distributed over the six linkage groups of C. elegans. The phenotypes are described for the mutants from the 9 complementation groups not previously reported on in detail. Most are paralyzed, but some exhibit essentially normal movement; mutants of two loci show changes only in later larval stages and adulthood. Morphological studies show that, in general, all the members of a complementation group show similar changes in muscle structure and that these changes are distinctive for that group. In mutants of several genes, disorganization of the myofilament lattice is general with no one component of the lattice more obviously altered than the others. In mutants of other genes specific structures are prominently altered. In one of the instances where thick filaments appear to be abnormal, double mutants combining mutations in this gene (unc-82 IV) with mutations in the gene for a myosin heavy chain or paramyosin were used to show that the unc-82 gene product probably affects thick filament assembly through its actions on paramyosin. Some possible implications of the morphological features of the mutants as well as the conclusions derived from the genetic studies are discussed. ------------------- Key: 462 Medline: 81004836 Authors: Sulston JE;Albertson DG;Thomson JN Title: The C. elegans male: Postembryonic development of nongonadal structures. Citation: Developmental Biology 78: 542-576 1980 Type: ARTICLE Genes: Abstract: The nongonadal cells in the male nematode Caenorhabditis elegans have been followed through maturation by Nomarski microscopy. Many of the cells are incorporated into the copulatory apparatus, which includes the cloaca, copulatory spicules, sensilla, and musculature. This region has been reconstructed by serial section electron microscopy in order to identify the cell types that arise from known lineages. With the exception of certain bilaterally symmetrical pairs the cells have invariant fates. The development involves a variety of well-defined cell interactions, individual and collective cell movements, cell deaths mediated by designated killers, and the reorganisation of a muscle. The male structures overlie an almost unchanged hermaphrodite tail; their development is more complex than that of the hermaphrodite, and more ------------------- Key: 463 Medline: 81004837 Authors: Sulston JE;White JG Title: Regulation and cell autonomy during postembryonic development of C. elegans. Citation: Developmental Biology 78: 577-597 1980 Type: ARTICLE Genes: Abstract: The role of cell-cell interaction in the postembryonic development of nongonadal tissues in the nematode Caenorhabditis elegans has been explored by selective cell ablation with a laser microbeam. Examples have been found of induction and of regulation in cell lineage and fate. Regulation in which one cell precisely or partially replaces another is seen, but only in certain groups of hypodermal cells which resemble one another closely; cells which are unique are not replaced in this way. The regulation of cell form is more widespread and less ------------------- Key: 464 Medline: 80254944 Authors: Lewis JA;Wu CH;Levine JH;Berg H Title: Levamisole-resistant mutants of the nematode C. elegans appear to lack pharmacological acetylcholine receptors. Citation: Neuroscience 5: 967-989 1980 Type: ARTICLE Genes: ace-1 ace-2 cha-1 lev-1 lev-8 lev-9 lev-10 lev-11 unc-17 unc-18 unc-22 unc-29 unc-30 unc-38 unc-50 unc-51 unc-57 unc-63 unc-68 unc-74 Abstract: The body muscles of the nematode Caenorhabditis elegans contract when the animal is cut in solutions of cholinergic agonists. The pharmacological specificty of the apparent nematode cholinergic receptor is most like a vertebrate nicotinic ganglionic receptor. The anthelmintic levamisole resembles nicotine in its effects and acts directly or indirectly as both a cholinergic agonist and antagonist. Mutants at 7 loci conferring extreme resistance to levamisole respond very poorly to cholinergic agonists effective on the wild type. These mutants all share the same uncoordinated motor behavior and contract like the wild type in response to the noncholinergic muscle agonist ouabain. The uncoordinated motor behavior of the mutants and the resistance to levamisole and cholinergic agonists can be copied by exposing the wild type to the cholinergic blocking agent mecamylamine. Another class of mutants (8 loci, 5 corresponding to loci also producing extremely resistant alleles) possess intermediate resistance to levamisole and cholinergic agonists and behaves pharmacologically and genetically like mutants moderately impaired in the levamisole-senstive function. A third class of mutants (2 loci) with spasmodic muscle twitching is partially resistant to cholinergic agonists and to ouabain and probably represents defects in the muscle-contraction cycle physiologically downstream from the levamisole-sensitive function. Meta-phenyl-substituted derivatives of levamisole retain considerable biological activity and may be useful in the molecular analysis of our mutants. a-bungarotoxin, benzyltrimethylammonium, and 3-quinuclidinyl benzilate, potential probes of cholinergic receptor function, do not show significant activity in our cut worm assay. The nature of the observed cholinergic response and the neuroanatomy of C. elegans suggests that the primary response occurs at muscle synapses. We believe that the physiological defect the extremely resistant mutants share is a severe lack of functional muscle acetylcholine receptors and that most of the wild type function of this molecule is not essential to the life of C. elegans. The ability to obtain such mutants may result from there being more than one pharmacological type of nematode cholinergic muscle receptor and/or from the coexistence of a noncholinergic motor mechanism. More generally, the ease with which levamisole-resistant mutants can be isolated (up to 74 mutants in one gene) makes these mutants a favorable system for understanding how a small group of related genes functions in a simple animal. ------------------- Key: 465 Medline: Authors: Cox GN;Laufer JS;Kusch M;Edgar RS Title: Genetic and phenotypic characterization of roller mutants of C. elegans. Citation: Genetics 95: 317-339 1980 Type: ARTICLE Genes: bli-1 bli-2 dpy-2 dpy-3 dpy-4 dpy-7 dpy-8 dpy-10 dpy-11 rol-1 rol-3 rol-4 rol-6 sqt-1 sqt-2 sqt-3 Abstract: Eighty-eight mutants of C. elegans that display a roller phenotoype (a helically twisted body) have been isolated and characterized genetically and phenotypically. The mutations are located in 14 different genes. Most genes contain a number of alleles. Their distribution among the chromosomes appears nonrandom, with seven of the genes being located on linkage group II, some very closely linked. The phenotypes of the mutants suggest that there are five different classes of genes, each class representing a set of similar phenotypic effects: Left Roller (four genes), Right Roller (one gene), Left Squat (one gene), Right Squat (two genes) and Left Dumpy Roller (six genes). The classes of mutants differ with respect to a number of characteristics that include the developmental stages affected and the types of aberrations observed in cuticle structure. A variety of gene interactions were found, arguing that these genes are involved in a common developmental process. The presence of alterations in cuticle morphology strongly suggests that these genes are active in the formation of the nematode cuticle. ------------------- Key: 466 Medline: Authors: Abdulkader N;Brun J Title: A temperature-sensitive mutant of C. elegans var Bergerac affecting morphological and embryonic development. Citation: Genetica 51: 81-92 1979 Type: ARTICLE Genes: Abstract: Genetic, physiological, morphological and anatomical studies have been made on a 0.1 M EMS-induced temperature sensitive (ts) mutation affecting development and morphology of the hermaphroditic nematode C. elegans, var. Bergerac. The three mutated characters; (1) ts recessive lethality at temperature greater than or equal to 22.5C; (2) ts recessive body length at sublethal temperature 20C; (3) temperature-dependent semi-dominant abnormal tail form, show an absolute linkage. Ts lethal and body length periods are embryonic, monophasic and almost completely overlapping. Animals blocked in the lethal phase, which occurs during the first larval stage, are 'dumpy' with abnormal enlarged anterior regions and zig-zag intestines. The variation of these abnormalities at different permissive (13 and 18C) and restrictive (20, 22.5, 24 and 26C) tempertures shows (1) a decrease in the length of newly-hatched larvae with increased temperature, the decreae being particularly marked between 18 and 20C; (2) an increase in morphological and anatomical abnormalities with temperature. The evolution of the mutated phenotypes with temperature suggests that the activity of the ts genic product, which could take part in the production of the cuticle, decreases gradually with temperature. The origin of the ts genic product and its temperature-sensitivity are discussed in terms of the results of heat shock ------------------- Key: 467 Medline: Authors: Dusenbery DB;Barr J Title: Thermal limits and chemotaxis in mutants of the nematode C. elegans defective in thermotaxis. Citation: Journal of Comparative Physiology 137: 353-356 1980 Type: ARTICLE Genes: Abstract: Four mutant strains of the nematode Caenorhabditis elegans previously isolated as defective in thermotaxis were compared to the wild type in tests of their thermal range of activity and chemotaxis. The cold side of the temperature-activity curves of all four strains were different from wild type. The curves of the two cryophilic strains (EH65 and EH67) were shifted to colder temperatures. The curves of the other two mutant strains were shifted to warmer temperatures. In tests of chemotaxis to a variety of stimuli, strain EH61 made no response to any, EH71 made weak responses to all, and the remaining two strains made responses equal to wild type except for weaker responses to three chemical stimuli. It is concluded that thermotaxis shares specific gene requirements with processes controlling both thermal limits ------------------- Key: 468 Medline: Authors: Hosono R Title: A study of morphology of C. elegans: A mutant of C. elegans with dumpy and temperature-sensitive roller phenotype. Citation: Journal of Experimental Zoology 213: 61-67 1980 Type: ARTICLE Genes: dpy-10 dpy-13 Abstract: The wild-type nematode Caenorhabditis elegans has an elongated and spindle-shaped body, whereas the dumpy mutant has a shorter body with approximately the same diameter. Although the wild-type nematode moves forward by producing sinusoidal waves along the body, the roller mutant moves by rotating the body left or right around its long-body axis. A temperature-sensitive morphological mutant which develops into an adult with dumpy phenotype at 15C, but with roller phenotype at 25C, in addition to dumpy phenotype, was isolated. The dumpy phenotype appeared at the first larval stage and was complete at the fourth larval stage; the roller behavior was also expressed at the fourth larval stage. The heterozygous offspring (F1), produced by crossing the mutant hermaphrodite with wild-type males, were rollers in both hermaphrodites and males. Therefore, the dumpy character is autosomal recessive, and the roller character is dominant in heterozygote but cold-sensitive in homozygote. The dumpy mutation was mapped as allele of dpy-10 gene of linkage group II (LG II). The F2 progeny, produced by self-fertilization of the F1 roller hermaphrodite, segregated to wild, dumpy, and roller animals in a ratio of 1:1:2. An attempt to isolate from the F2 generation the roller mutant which produces no dumpy progeny was entirely unsuccessful. Therefore, the dumpy and the roller phenotypes are produced by closely linked mutations or perhaps by a single mutation. ------------------- Key: 469 Medline: 81004191 Authors: Hosono R;Sato Y;Aizawa SI;Mitsui Y Title: Age-dependent changes in mobility and separation of the nematode C. elegans. Citation: Experimental Gerontology 15: 285-289 1980 Type: ARTICLE Genes: Abstract: It has generally been believed that a senescent state is brought about by the loss of division ability of essential cells or the disappearance of irreplaceable components. Since aging shows considerable individual variations, it is difficult to pursue the problem in any single species. Analysis of population aging have been mainly done by measuring a decrease in the population size. However, the decrease in population size involves not only senescent death but also death due to other changes, and it is not suitable for defining the aging process precisely. Therefore, the study of aging should be carried out in the populations with genetic and environmental similarity, and select several characteristics which are closely related to the senescent process. The nematode Caenorhabditis elegans is easy to handle and it is possible to obtain many individuals with identical genetic background. Information on aging phenotypes of the nematode has been accumulated. But in spite of their identical genetic background in synchronous cultures, individual differences in life span are conspicuous. The maximum life span of wild hermaphrodites at 20C was double the minimum life span in C. elegans. Since aging reflects various biological histories following maturation, individual death has many causes. One way to identify sub-groups is to classify an aged population on the basis of other aging parameters. Previously one of the authors (R.H.) has reported behavioral changes accompanying aging of C. elegans. In this report, we classified the worm population on the basis of difference in movement activity and examined some aging parameters of these fractionated populations. ------------------- Key: 470 Medline: 81033740 Authors: Siddiqui SS;Babu P Title: Genetic mosaics of C. elegans: A tissue-specific fluorescent mutant. Citation: Science 210: 330-332 1980 Type: ARTICLE Genes: flu-3 Abstract: Genetic mosaics can be generated by x-irradiation in the simple nematode Caenorhabditis elegans. A mutation in the gene flu-3 alters the characteristic autofluorescence of intestinal cells under ultraviolet light and can be used as a cell- and tissue-specific marker. Embryos heterozygous for flu-3 give rise to adults with patches of these altered intestinal cells. The previously established intestinal cell lineage in Caenorhabditis elegans and the distribution and sizes of the fluorescent patches are consistent with a somatic segregation of the flu-3 allele. ------------------- Key: 471 Medline: 81054930 Authors: Karn J;Brenner S;Barnett L;Cesareni G Title: Novel bacteriophage lambda cloning vector. Citation: Proceedings of the National Academy of Sciences USA 77: 5172-5176 1980 Type: ARTICLE Genes: unc-54 Abstract: A simple method for generating phage collections representing eukaryotic genomes has been developed by using a novel bacteriophage lambda vector, lambda1059. The phage is a BamH1 substitution vector that accommodates DNA fragments 6-24 kilobases long. Production of recombinants in lambda1059 requires deletion of the lambda red and gamma genes. The recombinants are therefore spi- and may be separated from the spi+ vector phages by plating on strains lysogenic for bacteriophage P2. Random fragments suitable for insertion into lambda1059 are obtained by partial digestion of high molecular weight eukaryotic DNA with Sau3a. This restriction enzyme cleaves at the sequence G-A-T-C and leaves a 5'-tetranucleotide "sticky end." Because G-A-T-C extensions are also produced by BamH1 cleavage, these fragments may be annealed directly to BamH1-cleaved lambda1059. By using these methods, a set of clones covering the entire Caenorhabditis elegans genome was constructed. DNA segments which include the unc-54 myosin heavy chain gene have been isolated from this ------------------- Key: 473 Medline: Authors: von Ehrenstein G;Schierenberg E Title: Cell lineages and development of C. elegans and other nematodes. Citation: "Nematodes as Biological Models, Volume 1: Behavioral and Developmental Models." Zuckerman BM (ed), Academic Press, NY. 1: 1-72 1980 Type: REVIEW Genes: Abstract: Studies on the development of nematodes began about 100 years ago. Nematodes have a unique combination of favorable properties for the microscopic observation of development. These include transparent small eggs and a reproducible cleavage leading to an animal with a constant number of cells and a relatively simple anatomy. Nematodes have been classic models for studying the processes of egg maturation, meiosis, fertilization, zygote formation, and early cleavage... ------------------- Key: 474 Medline: Authors: Zengel JM;Epstein HF Title: Muscle development in C. elegans: A molecular genetic approach. Citation: "Nematodes as Biological Models, Volume 1: Behavioral and Developmental Models." Zuckerman BM (ed), Academic Press, NY. 1: 73-126 1980 Type: REVIEW Genes: Abstract: Muscle contraction is one of the fundamental processes of animal life. Although biochemical, biophysical, and electron microscopic studies have yielded much valuable information about the structure and function of muscle and its component proteins, there are still many unanswered questions. For example, little is known about the molecular basis for gene expression during the development of muscle, the regulation of synthesis and function of muscle proteins, and the in vivo assembly of the myofilament lattice. Progress in answering these types of questions has been hindered in the past by the lack of a system in which one could use biochemical, biophysical, and cytological techniques in analyzing an animal also suitable for genetic and developmental studies of muscle. However, recent work has demonstrated rather convincingly that the nematode, Caenorhabditis elegans, will be very useful for attacking these problems. ------------------- Key: 475 Medline: Authors: Dusenbery DB Title: Behavior of free-living nematodes. Citation: "Nematodes as Biological Models, Volume 1: Behavioral and Developmental Models." Zuckerman BM (ed), Academic Press, NY. 1: 127-158 1980 Type: REVIEW Genes: Abstract: The nematodes form a very important group of animals that have received much less study than deserved. They appear to be nearly as important in human health and agriculture as insects, and yet there are ten times as many entries in Biological Abstracts for the latter. Even from a less ethnocentric point of view, nematodes are significant. Hyman (1951) estimates 500,000 nematode species, which is of the same order as is the number of insect species. In soil, where comparisons have been made, the biomass of the two groups is roughly equal. The great disparity in research effort is simply because nematodes are much less visible to the casual observer. As a consequence of this situation, there is a need for basic biological research on nematodes. Much of the required work could be done on any typical nematode species, and since the free-living microphagous forms are most convenient to work with, they are of great interest. One of the areas in which basic knowledge is lacking for this group is that of behavior. This void is particularly surprising in view of the fact that behavior is presumably one of the more important aspects of parasitic lifestyles. It is also unfortunate from the point of view of basic behavioral biology. Nematodes and their close relatives occupy a unique place in the evolution of the nervous system. They are the only readily studied organisms that have been shown to have a centralized nervous system made up of a specific and countable number of neurons. The nematodes that have been examined have about 200 neurons depending on the species. In contrast, two annelids that have been studied have 10*4 and 10*5 neurons, and an arthropod is estimated to have 10*5 neurons. On the other hand, more primitive nervous systems are apparently not eutelic and often consist of a dispersed nerve net. Thus, it is of general biological interest to determine the behavioral capacities of ------------------- Key: 476 Medline: Authors: Johnson CD;Stretton AOW Title: Neural control of locomotion in Ascaris: anatomy, electrophysiology, and biochemistry. Citation: "Nematodes as Biological Models, Volume 1: Behavioral and Developmental Models." Zuckerman BM (ed), Academic Press, NY. 1: 159-196 1980 Type: REVIEW Genes: Abstract: Locomotory behavior has been investigated in a wide variety of animals, including nematodes. Many studies have concluded that locomotory behavior is under neurogenic control, i.e., during locomotion the coordinated contractions of relevant muscles results from a coordinated firing of motoneurons. Nematodes have long been known to have only a small number of neurons (about 250 in the adult female), an attribute which should make them an attractive simple system in which to examine the control of locomotion. It should be possible, for example, to examine the role of individual neurons in the control of locomotion and also to determine which interactions between neurons are responsible for locomotory behavior. These studies have not been previously attempted primarily because the anatomy of nematode motoneurons had not been determined (a situation recently remedied, see Section IV, B). In the absence of this knowledge, the analysis of nematode locomotion has concentrated on the role of interconnections between muscle cells, and has been dominated by the suggestion that the coordinated contraction of muscle cells results from these interconnections (i.e., myogenic control of locomotion). In these models, the nervous system is relegated to switching the musculature between different patterns of contraction (i.e., directions of wave propagation). This type of organization has been called neurocratic. It is not yet clear whether the control of locomotion in nematodes in neurogenic or myogenic. Our bias (which will be clear) is that it is the nervous system which plays the major role, but the crucial experiments ------------------- Key: 477 Medline: Authors: Willett JD Title: Control mechanisms in nematodes. Citation: "Nematodes as Biological Models, Volume 1: Behavioral and Developmental Models." Zuckerman BM (ed), Academic Press, NY. 1: 197-226 1980 Type: REVIEW Genes: Abstract: Complete information regarding the detailed control mechanisms involved in any specific aspect of nematode physiology or biochemistry is currently not available. There are, however, numerous examples of physiological responses and biochemical changes taking place during the course of the nematode life cycle which will give indications of being under neural and/or hormonal control. In some instances, experimental evidence exists of a particular control system. Though relatively simple in cellular architecture, nematodes possess a number of morphologically and functionally distinct tissues. It is not unreasonable to expect that with this diveristy in tissue function nematodes will be found to possess a system of inter- and intracellular controls not unlike those encountered in higher metazoa. Nematodes display specific behavior in response to both external as well as internal signals. Alterations in its external environment can be detected, recorded, and responded to by the nematode. The response can be reflected in behavioral, physiological, and/or long-term biochemical changes within the organism. Several processes inherent to the nematode life cycle must of necessity reflect the operation of a system of controls. Some experimental evidence concerning the nature of these control systems is available. Neglecting the contol processes involved in embryogenesis and concentrating on postembryonic development and reproduction, there are a number of specific events likely to be under the control of neural and/or hormonal processes... ------------------- Key: 478 Medline: Authors: Herman RK;Horvitz HR Title: Genetic analysis of C. elegans. Citation: "Nematodes as Biological Models, Volume 1: Behavioral and Developmental Models." Zuckerman BM (ed), Academic Press, NY. 1: 227-262 1980 Type: REVIEW Genes: Abstract: Largely through the efforts of Sydney Brenner, many investigators have been attracted to Caenorhabditis elegans as a model organism for asking questions about the genetic basis of eucaryotic development and animal behavior. The philosophy underlying this interest is that of molecular genetics, which has relied heavily on the analysis of single-step mutants to elucidate such genetically controlled processes as metabolic pathways, the regulation of procaryotic gene expression, and the in vivo assembly of bacteriophages. Development and behavior also make use of genetic programs, and it may help to mutate the program steps to discern their nature. At present this seems an enormous undertaking because morphogenesis and behavior, as we now understand them, seem very remote from the genes that control them. Clearly other techniques--physiological, biochemical, anatomical--will be required. But the philosophy behind much C. elegans research is that mutant analysis will ultimately play a valuable role in understanding development and behavior. With this philosophy in mind, the attraction of C. elegans is twofold: suitability for genetic analysis and relative cellular simplicity. The latter feature is reviewed by others in this volume. The purpose of this review is to summarize the current status of the genetics of C. elegans; the applications of genetic analysis to the problems of development and behavior will be left to other reviewers and future work. ------------------- Key: 479 Medline: Authors: Riddle DL Title: Developmental genetics of C. elegans. Citation: "Nematodes as Biological Models, Volume 1: Behavioral and Developmental Models." Zuckerman BM (ed), Academic Press, NY. 1: 263-284 1980 Type: REVIEW Genes: Abstract: Caenorhabditis elegans is widely accepted as an important model organism for the study of animal development and behavior. A dozen new research groups studying this nematode have been established within the past five years. Caenorhabditis elegans offers many advantages for studying a variety of biological processes, but the most important of these advantages is the ability to carry out all types of genetic manipulations. Virtually all of the research utilizing C. elegans relies in some way on its genetics. This research is primarily long term, since much of it is aimed at an understanding of the molecular basis of developmental and behavioral processes. ------------------- Key: 480 Medline: Authors: Siddiqui SS;von Ehrenstein G Title: Biochemical genetics of C. elegans. Citation: "Nematodes as Biological Models, Volume 1: Behavioral and Developmental Models." Zuckerman BM (ed), Academic Press, NY. 1: 285-312 1980 Type: REVIEW Genes: Abstract: In addition to the extensively studied class of mutants with alterations of muscle organization (this volume, Chapter 2), mutants with enzymatic defect are being investigated in Caenorhabditis elegans. This chapter reviews mutants affecting kynurenine hydrolylase, kynureninase, acetylcholinesterase, choline acetyltransferase, and endodeoxyribonuclease. Also included are mutants altered in the metabolism of ------------------- Key: 481 Medline: Authors: Dusenbery DB Title: Chemotactic behavior of mutants of the nematode C. elegans that are defective in osmotic avoidance. Citation: Journal of Comparative Physiology 137: 93-96 1980 Type: ARTICLE Genes: che-3 daf-10 osm-1 osm-5 osm-6 Abstract: Wild-type C. elegans and seven derivative strains previously selected for absence of the wild-type tendency to avoid highly concentrated solutions were tested for responsiveness in 11 assays of chemotaxis, including 6 attractant and 3 repellent stimuli. The two strains altered in the gene osm-1 (P808 and P816) did not respond in any test except, possibly, one or two weak responses. Strain P801 responded to one attractant and two repellents. Strain P802 made moderately strong responses to most stimuli and avoided CO2 in phosphate buffer weakly, if at all, but did respond to the attractants Na+ and Cl-. Conversely, strains P813 and P811 made little if any response to any attractant but did respond to the two strong repellents. Taken together with other results, these findings suggest that the osmotic response has more gene requirements in common with both attractive and repellent chemical stimuli than with thermal or mechanical stimuli. In addition, they indicate that the known chemical stimuli and the osmotic stimulus are probably ------------------- Key: 482 Medline: 81077343 Authors: Kass IS;Wang CC;Walrond JP;Stretton AOW Title: Avermectin B1a, a paralyzing anthelmintic that affects interneurons and inhibitory motoneurons in Ascaris. Citation: Proceedings of the National Academy of Sciences USA 77: 6211-6215 1980 Type: ARTICLE Genes: unc-29 Abstract: Avermectin B1a (AVM) is an antiparasitic agent that paralyzes nematodes without causing hypercontraction or flaccid paralysis. Using selective stimulation techniques, we have shown that AVM blocks transmission between interneuron(s) and excitatory motorneurons in the ventral nerve cord of Ascaris. It also inhibits transmissin between inhibitory motoneurons and muscle but has little effect on excitatory neuromuscular transmission. Picrotoxin can reverse the AVM- induced block of interneuron-excitatory motoneuron transmission but has no effect on the inhibitory motoneuronal synapse in either the presence or absence of AVM. Our results provide an explanation of how AVM may cause paralysis of nematodes. ------------------- Key: 483 Medline: 81054813 Authors: Stinchcomb DT;Thomas M;Kelly J;Selker E;Davis RW Title: Eukaryotic DNA segments capable of autonomous replication in yeast. Citation: Proceedings of the National Academy of Sciences USA 77: 4559-4563 1980 Type: ARTICLE Genes: Abstract: A selective scheme is presented for isolating sequences capable of replicating autonomously in the yeast Saccharomyces cerevisiae. YIp5, a vector that contains the yeast gene ura3, does not transform a ura3 deletion mutant to Ura+. Hybrid YIp5-Escherichia coli DNA molecules also fail to produce transformants. However, collections of molecular hybrids between YIp5 and DNA from any of six eukaryotes tested (S. cerevisiae, Neurospora crassa, Dictyostelium discoideum, Caenorhabditis elegans, Drosophila melanogaster, and Zea mays) do transform the deletion mutant. The Ura+ transformants grow slowly, are unstable under nonselective conditions, and carry transforming DNA as autonomously replicating, supercoiled circular molecules. Such a phenotype is qualitatively identical to that of strains transformed by molecules containing a yeast chromosomal origin of replication. Thus, these DNA hybrid molecules may contain eukaryotic origins of replication. The isolated sequences may be useful in determining the signals controlling DNA replication in yeast and in studying both DNA replication and transformation in other eukaryotic organisms. ------------------- Key: 484 Medline: 81139611 Authors: Lewis JA;Wu CH;Berg H;Levine JH Title: The genetics of levamisole resistance in the nematode C. elegans. Citation: Genetics 95: 905-928 1980 Type: ARTICLE Genes: dpy-4 dpy-13 lev-1 lev-8 lev-9 lev-10 lev-11 sup-5 unc-22 unc-26 unc-29 unc-38 unc-50 unc-51 unc-57 unc-63 unc-68 unc-74 Abstract: We have characterized a small group of genes (13 loci) in the nematode Caenorhabditis elegans that, when mutated, confer resistance to the potent anthelmintic levamisole. Mutants at the 7 loci conferring the most extreme resistance generally possess almost identical visible and pharmacological phenotypes: uncoordinated motor behavior, most severe in early larval life, extreme resistance to cholinergic agonists and sensitivity to hypo-osmotic shock. Mutants with exceptional phenotypes suggest possible functions for several of the resistance loci. The most extreme mutants can readily be selected by their drug resistance (211 mutants, as many as 74 alleles of one gene). The more common resistance loci are likely to be unessential genes, while loci identified by only a few alleles may be essential genes or genes conferring resistance only when mutated in a special way. We propose that these mutants represent a favorable system for understanding how a small group of related genes function in a simple animal. The extreme drug resistance of these mutants makes them useful tools for the genetic manipulation of C. elegans. And, as the most resistant class of mutants might lack pharmacologically functional acetyl-choline receptors (LEWIS et al. 1980), these mutants may also be of some neurobiological significance. ------------------- Key: 485 Medline: 81112143 Authors: Mackenzie JM Jr;Epstein HF Title: Paramyosin is necessary for determination of nematode thick filament length in vivo. Citation: Cell 22: 747-755 1980 Type: ARTICLE Genes: unc-15 Abstract: Nematodes construct thick filaments in body-wall muscle cells using three major protein components: two kinds of myosin and paramyosin. We report the isolation and enrichment of thick filaments from wild type and mutant strains of the nematode, Caenorhabditis elegans, and their examination by electron microscopy. We have compared the morphology and distribution of lengths of isolated filaments from the wild type N2, the unc-15 mutant lacking paramyosin E1214 and the unc-54 mutant lacking specific body-wall mysoin E190. Our studies indicate that very long filaments can be isolated from both N2 and the E190 lacking 60% of the normal amount of myosin and that the mean length of these isolated filaments and filament fragments in these strains is 3.2 and 3.3 um, respectively. However, when similar preparations of thick filaments isolated from E1214 were examined, no long filaments were observed and the mean length was 1.0 um. Most of the E1214 filaments exhibited prominent central bare zones and double tapered ends. The mean length of this normally distributed subpopulation was 1.53 um. For comparison, we determined the in situ length of wild type N2 thick filaments (by polarized light microscopy of body-wall muscle) to be 9.7 um. The diameters of the wild type N2 and the myosin mutant E190 thick filaments were 25 nm uniformly along their length, whereas the paramyosin mutant E1214 filaments showed wider diameters of 32 nm along most of their length. We conclude that functional paramyosin is necessary for the determination of thick filament length and diameter in nematode body-wall muscle cells in vivo. The presence of both body-wall myosins and other myofibrillar components appear insufficient for determination of thick filament structure in these muscles. Both body-wall myosins are unnecessary for the formation of long thick filaments of normal diameter: the presence of one form of myosin, paramyosin and other myofibrillar components is sufficient. We discuss the relevance of these findings to thick filament assembly and myofibrillar organization in general. ------------------- Key: 486 Medline: 81139614 Authors: Greenwald IS;Horvitz HR Title: unc-93(e1500): A behavioral mutant of C. elegans that defines a gene with a wild-type null phenotype. Citation: Genetics 96: 147-164 1980 Type: ARTICLE Genes: daf-2 daf-7 dpy-1 dpy-17 lin-8 lon-1 sup-9 sup-10 unc-3 unc-79 unc-85 unc-93 nDf2 nDf3 nDf4 nDf5 nDf6 nDf7 nDf8 nDf9 mnDf1 mnDf4 mnDf8 nDf10 nDf11 nDf12 nDf13 nDf14 nDf15 mnDf11 mnDf19 Abstract: The uncoordinated, egg-laying-defective mutation, unc-93(e1500) III, of the nematode Caenorhabditis elegans spontaneously reverts to a wild-type phenotype. We describe 102 spontaneous and mutagen-induced revertants that define three loci, two extragenic (sup-9 II and sup- 10 X) and one intragenic. Genetic analysis suggests that e1500 is a rare visible allele that generates a toxic product and that intragenic reversion, resulting from the generation of null alleles of the unc-93 gene, eliminates the toxic product. We propose that the genetic properties of the unc-93 locus, including the spontaneous reversion of the e1500 mutation, indicate that unc-93 may be a member of a multigene family. The extragenic suppressors also appear to arise as the result of elimination of gene activity; these genes may encode regulatory functions or products that interact with the unc-93 gene product. Genes such as unc-93, sup-9 and sup-10 may be useful for genetic manipulations, including the generation of deficiencies and mutagen testing. ------------------- Key: 487 Medline: 81087907 Authors: Mounier N;Brun J Title: A cytogenetical analysis of sterile mutants in C. elegans. Citation: Canadian Journal of Genetics & Cytology 22: 391-403 1980 Type: ARTICLE Genes: Abstract: The regulation of gametogenesis in the hermaphrodite and proterandrous nematode Caenorhabditis elegans is introduced here through the analysis of nonconditional sterile mutants. To investigate the mechanisms which allow the two gametogenetic phases to succeed each other in the same ovotestis, three mutants were studied cytogenetically. Two of the mutants exhibit only the spermatocyte phase and the third shows a greatly reduced and disturbed oogenesis. These three mutations all produce large decreases in ovotestis size and gonocyte number. Each of the three is monofactorial, recessive, autosomal and independent. Homozygous mutant males are also sterile. The gametogenesis phases which could be disturbed by mutation were determined by cytological analysis of the ovotestis of 12 other sterile strains. These phases occur during mitotic divisions of the genital primordium, zygotene chromosome pairing, male meiosis and spermiogenesis, oogenesis induction and oocyte maturation. These steps of gametogenesis need a wild-type genic activity to occur normally. It appears that spermatogenesis and oogenesis are two genetically independent processes, and that oogenesis is rather autonomous and its induction would depend on a hormonal factor. ------------------- Key: 488 Medline: 83077080 Authors: Zengel JM;Epstein HF Title: Identification of genetic elements associated with muscle structure in the nematode C. elegans. Citation: Cell Motility 1: 73-97 1980 Type: ARTICLE Genes: unc-27 unc-45 unc-52 unc-60 unc-78 unc-82 unc-87 unc-89 unc-90 unc-94 unc-95 unc-96 unc-97 unc-98 unc-100 Abstract: A search for new mutants with altered body-wall muscle cell structure has been undertaken in the nematode C elegans. One-hundred seventeen mutants were isolated after mutagenesis with ethyl methanesulfonate or ultraviolet light, enrichment by a motility-requiring test, and screening by polarized light microscopy; 102 of these mutants were in ten previously established genes, whereas 15 mutants permitted the identification of seven new complementation groups in C elegans. Two of the new genes map on linkage group I (unc-94 and unc-95) and four genes are sex linked (unc-96, unc-97, unc-98, and unc-99). One complementation group (unc-100) could not be mapped because of the special characteristics of its cohort mutants. Representative mutants of the mapped genes were examined by polarized light and electron microscopy. All of the mutants exhibit disruptions of the normal A and I band organization of thick and thin filaments. Several of the mutants produce collections of thin filament-like structures. In one of these cases, HE177 demonstrated collections of somewhat wider, intermediate-sized filaments as well, and the HE195 mutant produces paracrystalline aggregates of thin filaments amidst looser arrangements of similar structures. The mutants in newly identified genes, as well as the new mutants in previously established genetic loci, have promise as tools in the study of myofibrillar assembly and function. Among the 22 complementation groups associated with body- wall structure in C elegans, it is likely that some genes code for regulatory and morphogenetic functions in addition to the well- studied structural, contractile, and calcium-associated proteins in muscle. ------------------- Key: 489 Medline: 81177051 Authors: Laufer JS;von Ehrenstein G Title: Nematode development after removal of egg cytoplasm: Absence of localized unbound determinants. Citation: Science 211: 402-404 1981 Type: ARTICLE Genes: Abstract: Embryos of Caenorhabditis elegans develop into fertile adults after cell fragments, containing presumptive cytoplasm of somatic and germ line precursors, are extruded from uncleaved eggs or early blastomeres through laser-induced holes in the eggshells. This suggests that the determinate development of this worm is not dependent on the prelocalization of determinants in specific regions of the egg cytoplasm. ------------------- Key: 490 Medline: Authors: Willett JD;Rahim I;Geist M;Zuckerman BM Title: Cyclic nucleotide exudation by nematodes and the effects on nematode growth, development and longevity. Citation: Age 3: 82-87 1980 Type: ARTICLE Genes: Abstract: The levels of cyclic nucleotides, cAMP and cGMP, in the medium of aging mass cultures of Panagrellus redivivus were determined, respectively, by a protein binding assay and a radioimmunoassay. The amount of cGMP increased as the mass cultures aged while the amount of cAMP remained stable. Since premature death and an inhibition of development have been observed in aging mass cultures, investigators have speculated that a build-up of excretory products in the medium might be toxic to the nematodes and cause abnormal development. To examine this possibility, small cultures containing fixed numbers of the nematode Caenorhabditis elegans were exposed to levels of cGMP analagous to the levels found in aging mass cultures of P. redivivus. Significant increases in growth and longevity occurred with no effect on fecundity, timing or the duration of the reproductive period. It appears then that cGMP is not responsible for the toxic effects observed in mass culture and, in fact, cGMP apparently enhances nematode longevity at concentrations which do not alter development. ------------------- Key: 491 Medline: Authors: Edgar RS Title: The genetics of development in the nematode C. elegans. Citation: "The Molecular Genetics of Development." Leighton T and Loomis WF (eds), Academic Press, NY. : 213-235 1980 Type: REVIEW Genes: osm-3 Abstract: The free-living nematode Caenorhabditis elegans has attracted attention in recent years as an organism for the study of the genetic control of development. This chapter briefly describes the present state of this work. Many of the studies reported on here have not yet been published but have been described in "The Worm Breeder's Gazette", an informal newsletter I edit, and at a C. elegans meeting held at Cold Spring Harbor in May 1979. A previous review of this field was written by Riddle (1978). The use of free-living nematodes in genetic studies was first suggested by Dougherty and Calhoun in 1948. Early studies of C. elegans by Dougherty and co-workers (1959) emphasized methods of axenic cultivation while the sexual cycle was described by Nigon (1949). The present interest in C. elegans, however, was triggered by Sydney Brenner who took up the organism in the late 1960s as a possibly useful organism for the study of the genetic control of the nervous system and of behavior (Brenner, 1973). It was largely due to Brenner (1974) that the present methods of cultivation and of genetic analysis were developed. ------------------- Key: 492 Medline: 81242433 Authors: Emmons SW;Rosenzweig B;Hirsh D Title: Arrangement of repeated sequences in the DNA of the nematode C. elegans. Citation: Journal of Molecular Biology 144: 481-500 1980 Type: ARTICLE Genes: Abstract: The arrangement of repeated sequences in the DNA of the nematode Caenorhabditis elegans has been studied by electron microscopy and reassociation kinetics. Inverted repeats observed in the electron microscope are mostly less than 1000 base-pairs in length and are distributed randomly with an average separation of 33,000 bases. Comparison of the number and distribution of these inverted repeats with the amount of DNA in the foldback fraction isolated by hydroxyapatite chromatography suggests that much of the material in the foldback fraction contains a sequence distinct from the class of inverted repeats observed in the electron microscope. Cot analysis of DNA fragments several thousand nucleotides in length shows that moderately repetitive sequences are interspersed with unique sequences. Most of these interspersed, repeated sequences are a few hundred nucleotides in length, as determined from electron micrographs. DNA sequence arrangement in C. elegans is therefore similar to the arrangement found in most other eukaryotes. ------------------- Key: 493 Medline: 81122166 Authors: Bhat SG;Babu P Title: Mutagen sensitivity of kynureninase mutants of the nematode C. elegans. Citation: Molecular & General Genetics 180: 635-638 1980 Type: ARTICLE Genes: flu-2 Abstract: Mutants in the gene flu-2 of the free-living nematode Caenorhabditis elegans are characterised by an altered autofluorescence of the intestine cells, from the light blue of wild-type to a dull green colour. The properties of flu-2 mutants have been investigated. L- kynureninase activity has been detected in wild-type C. elegans. The flu-2 mutants have markedly reduced kynureninase activity, as predicted earlier from chromatographic analysis of tryptophan catabolites of wild-type and mutant worms. Associated with this enzymatic block, all flu-2 mutants have enhanced sensitivity to ethyl methane sulfonate (EMS) ------------------- Key: 494 Medline: 81139247 Authors: Kimble JE;White JG Title: On the control of germ cell development in C. elegans. Citation: Developmental Biology 81: 208-219 1981 Type: ARTICLE Genes: Abstract: After hatching, the germ line progenitor cells in C. elegans begin to divide mitotically; later, some of the germ line cells enter meiosis and differentiate into gametes. In the adult, mitotic germ cells, or stem cells, are found at one end (the distal end) and meiotic cells occupy the rest of the elongate gonad. Removal of two somatic gonadal cells, the distal tip cells, by laser microsurgery has a dramatic effect on germ cell development. In either sex, this operation leads to the arrest of mitosis and the initiation of meiosis in germ cells. The function of the distal tip cell in the intact animal appears to be the inhibition of meiosis (or stimulation of mitosis) in nearby germ cells. During development, this permits growth and, in the adult, it maintains the germ line stem cell population. A change in the position of the distal tip cell in the gonad at an early point in development is correlated with a change in the axial polarity of the germ line tissue. This suggests that the localization of the distal tip cell's inhibitory activity at the distal end of the gonad establishes the ------------------- Key: 495 Medline: 81261868 Authors: Argon Y;Ward S Title: C. elegans fertilization-defective mutants with abnormal sperm. Citation: Genetics 96: 413-433 1980 Type: ARTICLE Genes: fem-1 fer-1 fer-2 fer-3 fer-4 fer-6 fer-7 eDf1 Abstract: Seven new fertilization-defective mutants of C. elegans have been isolated and characterized; six are temperature sensitive, one is absolute and all are autosomal recessive. One mutation is in a previously described gene, while the other six define six new fer genes that appear to code for sperm-specific functions necessary for normal fertilization. In all fer mutants, both males and hermaphrodites accumulate sperm in near normal numbers. In hermaphrodites, mutant sperm contact the oocytes, but fail to fertilize them. Instead, the sperm are swept into the uterus by the passing oocytes and are expelled when oocytes are laid. Males of two fer mutants do not transfer sperm during copulation, but the other mutant males transfer sperm that fail to move to the spermatheca. Spermatozoa from fer-1 and fer-4 mutants are motility-defective in vitro as well as in vivo, and their pseudopods have an altered morphology. The period of development during which mutant hermaphrodites are temperature sensitive for fertility overlaps the time of sperm development. Some mutants are temperature sensitive throughout the entire period, and others are temperature sensitive during or just prior to spermiogenesis. In fer-4/+ and fer-7/+ males, the fertility of the mutation-bearing sperm is diminished, reducing the transmission ratio. This implies some post-meiotic expression of these genes.--This set of mutants provides a variety of functional and structural alterations in nematode sperm that should help identify and analyze gene products involved in sperm morphogenesis and ------------------- Key: 496 Medline: 81261869 Authors: Horvitz HR;Sulston JE Title: Isolation and genetic characterization of cell-lineage mutants of the nematode C. elegans. Citation: Genetics 96: 435-454 1980 Type: ARTICLE Genes: dpy-18 lin-1 lin-2 lin-3 lin-4 lin-5 lin-6 lin-7 lin-8 lin-9 lon-1 sup-5 sup-7 unc-59 unc-83 unc-84 unc-85 unc-86 Abstract: Twenty-four mutants that alter the normally invariant post-embryonic cell lineages of the nematode Caenorhabditis elegans have been isolated and genetically characterized. In some of these mutants, cell divisions fail that occur in wild-type animals; in other mutants, cells divide that do not normally do so. The mutants differ in the specificities of their defects, so that it is possible to identify mutations that affect some cell lineages but not others. These mutants define 14 complementation groups, which have been mapped. The abnormal phenotype of most of the cell-lineage mutants results from a single recessive mutation; however, the excessive cell divisions characteristic of one strain, CB1322, require the presence of two unlinked recessive mutations. All 24 cell-lineage mutants display incomplete penetrance and/or variable expressivity. Three of the mutants are suppressed by pleiotropic suppressors believed to be specific for null alleles, suggesting that their phenotypes result from the complete absence of gene activity. ------------------- Key: 497 Medline: 81261913 Authors: Meneely PM;Herman RK Title: Suppression and function of X-linked lethal and sterile mutations in C. elegans. Citation: Genetics 97: 65-84 1981 Type: ARTICLE Genes: let-1 let-2 let-3 let-4 let-5 let-6 let-7 let-9 let-10 let-11 let-12 let-14 let-15 let-16 let-18 let-33 let-34 let-35 let-36 let-37 let-38 let-39 let-40 let-41 unc-3 mnDf1 mnDf2 mnDf4 mnDf5 mnDf6 mnDf7 mnDf8 mnDf9 mnDp1 mnDp8 mnDp9 mnDf10 mnDf11 mnDf13 mnDf15 mnDf17 mnDf18 mnDf19 mnDf20 mnDf21 mnDf41 mnDf42 mnDf43 mnDp10 mnDp25 mnDp27 Abstract: We have expanded our collection of recessive lethal and sterile mutants in the region of the X chromosome balanced by mnDp1(X;V), about 15% of the X linkage map, to a total of 54 mutants. The mutations have been mapped with respect to 20 overlapping deficiencies and five X duplications, and they have been assigned to 24 genes by complementation testing. Nine mutants are hermaphrodite- sterile: one of these is a sperm-defect mutant, two have abnormal gonadogenesis and six, in five genes, are maternally influenced mutants, producing inviable zygote progeny. One of the gonadogenesis mutants and two of the maternally influenced mutants are male fertile. All but one of the maternally influenced mutants give cross progeny when mated with wild-type males. Forty-three mutants were tested for suppression by homozygous sup-5 (e1464), which is believed to be specific for null alleles. Ten mutants that were judged by independent criteria not to be null mutants are not suppressed. Nine of the other 33 mutants, in nine genes, are suppressed, five in both heterozygous and homozygous suppressor stocks and four only in homozygous suppressor stocks. ------------------- Key: 498 Medline: 81261882 Authors: Hodgkin J Title: More sex-determination mutants of C. elegans. Citation: Genetics 96: 649-664 1980 Type: ARTICLE Genes: dpy-21 fem-1 her-1 him-5 tra-1 tra-2 tra-3 vab-7 eDf1 eDf2 eDp6 Abstract: Sex determination in Caenorhabditis elegans is controlled by the X chromosome : autosome ratio, i.e. 2A;XX animals are hermaphrodite, and 2A;XO animals are male. A procedure for isolating 2A;XO animals that are transformed in;to hermaphrodites has been developed. Nine mutations causing this transformation have been obtained: eight are recessive, and all of these fall into a new autosomal complementation group, her-1 V. The remaining mutation (her-2) is dominant and has a genetic map location similar to that of tra-1 III. Recessive mutations of tra-1 cause the reverse transformation, transforming 2A;XX animals into males. Therefore, the her-2 mutation may result in constitutive expression of tra-1. Mutations in her-1 are without effect on XX animals, but the her-2 mutation prevents sperm production in both XX and XO animals, in addition to its effect on the sexual phenotype of XO animals. The epistatic relationships between tra and her genes are used to deduce a model for the action of these genes in controlling sex determination. ------------------- Key: 499 Medline: 81148607 Authors: Moerman DG;Baillie DL Title: Formaldehyde mutagenesis in the nematode C. elegans. Citation: Mutation Research 80: 273-279 1981 Type: ARTICLE Genes: dpy-4 let-51 let-53 let-56 let-58 let-59 let-60 unc-5 unc-22 sDf1 sDf2 Abstract: We have found that formaldehyde is capable of inducing mutations in the nematode Caenorhabditis elegans. 4 concentrations of formaldehyde were tested. At a concentration of 1%, formaldehyde is lethal to the nematode, and 0.01% formaldehyde did not induce any mutations in approx. 60 000 tested chromosomes. 2 concentrations of formaldehyde, 0.1% and 0.07%, were found to be mutagenic, inducing both point mutations and deficiencies in the unc-22 region of linkage group IV. 4 of the point mutations have been demonstrated to be alleles of the unc-22 gene and have been mapped within the locus. 2 of the putative deficiencies have been confirmed. Each spans the unc-22 gene and at least 2 other genes in the region. A rough estimate of the forward mutation frequency using 0.1% formaldehyde in this region is 3 X 10(- 5), while for 0.07% ------------------- Key: 500 Medline: 81189438 Authors: Sulston JE;Horvitz HR Title: Abnormal cell lineages in mutants of the nematode C. elegans. Citation: Developmental Biology 82: 41-55 1981 Type: ARTICLE Genes: lin-1 lin-2 lin-3 lin-4 lin-5 lin-6 lin-7 lin-8 lin-9 unc-59 unc-83 unc-84 unc-85 unc-86 Abstract: The phenotypes of cell lineage mutants of the nematode Caenorhabditis elegans are described. The mutants, which define 14 genes, differ in the breadth and nature of their phenotypic defects. Mutants in four genes display very general abnormalities in cell division and may be altered either in cellular maintenance and growth or in the mechanics of cell division and/or DNA replication. Mutants in two genes are specifically defective in the movements and divisions of certain hypodermal nuclei. Mutants in six genes are affected in vulva development in the hermaphrodite and, in some cases, in homologous aspects of sexual maturation in the male; some of these mutants are blocked in vulval cell divisions, wherease others under go extra divisions to generate multiple ectopic pseudovulvae; these genes appear to specify which of two alternative fates is assumed by a set of six cells involved in vulva development. Mutants in two genes produce reiteration in certain cell lineages, i.e., specific cells generate descendants similar to themselves in both their division patterns and the fates of their progeny; these genes may control primary determinative events that occur during the course of a cell lineage. ------------------- Key: 501 Medline: 81237401 Authors: Cassada R;Isnenghi E;Culotti M;von Ehrenstein G Title: Genetic analysis of temperature-sensitive embryogenesis mutants in C. elegans. Citation: Developmental Biology 84: 193-205 1981 Type: ARTICLE Genes: emb-1 emb-2 emb-3 emb-4 emb-5 emb-6 emb-7 emb-8 emb-9 emb-11 emb-12 emb-13 emb-14 emb-15 emb-16 emb-17 emb-18 emb-19 emb-20 emb-21 emb-22 emb-23 emb-24 emb-25 emb-26 emb-27 emb-28 emb-29 emb-30 emb-31 emb-32 emb-33 emb-34 emb-35 let-2 zyg-1 zyg-2 zyg-3 zyg-7 zyg-8 zyg-9 zyg-10 Abstract: A large set of temperature-sensitve (ts) embryonic arrest mutants in the nematode Caenorhabditis elegans has been isolated. Following ethylmethane sulfonate mutagenesis, ts mutants were identified from 10,000 segregated clones by replica plating from 16 to 25C. At least 54 independent ts developmental mutants showed embryonic arrest when the appropriate developmental stage was shifted up. These represent 28% of the independent developmental mutants from 294 ts clones from 155 mutagenized animals. Initial characterization of this subset of emb mutants is reported. Most of them arrest in middle or late embryogenesis with abnormal terminal phenotypes. Additional nonembryonic arrest stages (depending on shift-up regimen) suggest that many emb genes are also required for pre- or postembryonic development. For most of the emb mutants parental gene expression is sufficient for embryonic development at 25C. Based on complementation analysis of 37 new emb mutants together with 32 isolated by other investigators, 25 new emb genes are reported. This brings the total of embryonic arrest genes defined in C. elegans to 54. The new genes have been mapped approximately. In the present set, 10 emb genes map in the middle of linkage group III. The frequency of occurrence of second alleles gives on estimate (by Poisson analysis) for the number of genes required for embryogenesis of about 200. A second estimate is obtained from the fraction of 28% emb mutants among all ts lethal mutants in the screen; for an estimated 2000 essential genes in C. elegans, this corresponds to 560 genes required for embryogenesis. A small subset of highly mutable genes is also described. Results of the present screen for emb mutants are compared to those of others. Several ts mutants gave complex linkage results (apparently not due to double mutations), suggesting chromosome rearrangements. ------------------- Key: 502 Medline: 81189457 Authors: Chalfie M;Sulston J Title: Developmental genetics of the mechanosensory neurons of C. elegans. Citation: Developmental Biology 82: 358-370 1981 Type: ARTICLE Genes: mec-1 mec-2 mec-3 mec-4 mec-5 mec-6 mec-7 mec-8 mec-9 mec-10 mec-12 sup-5 sup-7 unc-86 eDf1 mnDf1 mnDf2 mnDf4 mnDf8 mnDf11 mnDp30 Abstract: Touch sensitivity in the nematode Caenorhabditis elegans is mediated by a set of six sensory neurons, the microtubule cells, of well-characterized anatomy and connectivity. The normal touch response is eliminated when these cells are killed by laser microsurgery. The identification of the microtubule cells as the mediators of touch sensitivity allows us to examine the effects of mutations on the development and differentiation of these cells. Forty-two touch-insensitive mutants have been isolated. These fall into 13 complementation groups. Mutations in five of the complementation groups have recognizable effects on the microtubule cells. These phenotypes include alterations of characteristic cellular ultrastructure, absence of neuronal process growth, and the absence of the cell (either by alterations in the patterns of cell divisions that give rise to the cells or by degeneration or death of existing cells). Because it is likely that we are approaching saturation of genes affecting primarily the microtubule cells, there appear to be relatively few genes that affect the growth and function of this class of cells and no ------------------- Key: 503 Medline: 81216070 Authors: Albert PS;Brown SJ;Riddle DL Title: Sensory control of dauer larva formation in C. elegans. Citation: Journal of Comparative Neurology 198: 435-451 1981 Type: ARTICLE Genes: che-3 daf-1 daf-2 daf-6 daf-10 Abstract: As a sensory response to starvation or overcrowding, Caenorhabditis elegans second-stage larvae may molt into a developmentally arrested state called the dauer larva. When environmental conditions become favorable for growth, dauer larvae mold and resume development. Some mutants unable to form dauer larvae are simultaneously affected in a number of sensory functions, including chemotaxis and mating. The behavior and sensory neuroanatomy of three such mutants, representing three distinct genetic loci, have been determined and compared with wild-type strain. Morphological abnormalities in afferent nerve endings were detected in each mutant. Both amphid and outer labial sensilla are affected in the mutant CB1377 (daf-6)X, while another mutant, CB1387 (daf-10)IV, is abnormal in amphidial cells and in the tips of the cephalic neurons. The most pleitropic mutant, CB1379 (che- 3)I, exhibits gross abnormalities in the tips of virtually all anterior and posterior sensory neurons. The primary structural defect in CB1377 appears to be in the nonneuronal amphidial sheath cells. The disruption of neural organization in CB1377 is much greater in the adult than in the L2 stage. Of all the anterior sense organs examined, only the amphids are morphologically affected in all three mutants. Thus, one or more of the amphidial neurons may mediate the sensory signals for entry into the dauer larva stage in normal animals. Using temperature-sensitive mutants we determined that the same defects which block entry into the dauer stage also prevent recovery of dauer larvae. ------------------- Key: 504 Medline: 81173090 Authors: Riddle DL;Swanson MM;Albert PS Title: Interacting genes in nematode dauer larva formation. Citation: Nature 290: 668-671 1981 Type: ARTICLE Genes: daf-1 daf-2 daf-3 daf-4 daf-5 daf-6 daf-7 daf-8 daf-10 daf-11 daf-12 daf-13 daf-14 daf-16 daf-18 daf-20 Abstract: The dauer larva of Caenorhabditis elegans is a developmentally arrested stage induced by starvation or overcrowding. Mutant genes controlling the ability to form dauer larvae interact in a way which allows them to be ordered in a pathway. Mutant phenotypes suggest that the pathway corresponds to neural processing of environmental stimuli. ------------------- Key: 505 Medline: 81237410 Authors: Swanson MM;Riddle DL Title: Critical periods in the development of the C. elegans dauer larva. Citation: Developmental Biology 84: 27-40 1981 Type: ARTICLE Genes: daf-1 daf-2 daf-4 daf-7 daf-8 daf-10 daf-14 Abstract: The dauer larva of Caenorhabditis elegans is a developmentally arrested stage formed at the second molt under conditions of starvation or overcrowding. It is specialized for long-term survival and dispersal. Dauer-constitutive (daf) mutants form dauer larvae even in an environment favorable for growth. Temperature-sensitive (ts) mutants representing six different genes have been subjected to temperature-shift and -pulse experiments in order to define the times of temperature sensitivity (TSPs). The results for five of the mutants, including one mutant with a maternal effect, show TSPs which bracket the first molt. The exceptional mutant, daf-14, has its TSP within the first larval stage. The TSPs of two mutants, daf-8 and daf-14, exhibit distinct major and minor phases. Temperature-pulse experiments discriminate between alternative interpretations of the temperature-shift data. All the results can be interpreted on the basis of normal and defective execution stages for the ts functions at permissive and restrictive temperatures. ------------------- Key: 506 Medline: 81243723 Authors: Bolanowski MA;Russell RL;Jacobson LA Title: Quantitative measures of aging in the nematode C. elegans. I. Population and longitudinal studies of two behavioral parameters. Citation: Mechanisms of Ageing & Development 15: 279-295 1981 Type: ARTICLE Genes: Abstract: As a first step in the quantitative characterization of senescence in the nematode Caenorhabditis elegans, we have studied movement wave frequency, defecation frequency, and whole-body water efflux as a function of age. Populations of C. elegans, strain N2, were cultured monoxenically on E. coli lawns at 20 degrees C. The median lifespan in such populations was approximately 12 days. Population mean movement wave frequency declined linearly with age (slope = -4.66 waves/minute per day). The decline in population mean defecation frequency (defecations per minute) was multiphasic, consisting of (1) a rapid decline (slope = -0.233 defecations/minute per day) from day 3 to day 6, (2) no apparent trend from day 6 to day 9, and (3) a gradual decline (slope = -0.089 defecations/minute per day) from 9 to day 14. Animals alive on or after day 15 were not observed to defecate. In longitudinal studies, individual animals exhibited linear declines in movement wave frequency and multiphasic declines in defecation frequency. For future population studies, the age- dependent declines in movement and defecation frequency appear sufficiently large and reproducible to a multiparametric description of senescence in C. elegans. One physiological parameter, 3H2O efflux, was found to be age-independent and to consist of two first- order rates. The half-times of the slow and fast efflux rates were approximately 15 and approximately 2.1 minutes, respectively. The two half-times and the fractions of 3H2O exhibiting the two half-times were invariant with ------------------- Key: 507 Medline: 81210196 Authors: Chalfie M;Horvitz HR;Sulston JE Title: Mutations that lead to reiterations in the cell lineages of C. elegans. Citation: Cell 24: 59-69 1981 Type: ARTICLE Genes: lin-4 unc-86 Abstract: Cells in the nematode Caenorhabditis elegans arise from invariant cell lineages. Mutations in two genes, unc-86 and lin-4, alter multiple and mutually exclusive sets of these lineages. In these mutants, particular cells repeat division patterns normally associated with their parental or grandparental progenitors. The effects of unc-86 are highly specific, altering in equivalent ways the lineages of three post-embryonic neuroblasts that in the wild- type undergo similar division patterns. The effects of lin-4 are more varied, resulting in a number of types of lineage reiterations as well as in supernumerary molts and the continued synthesis of larval- specific cuticle. The reiteration of a given cell division or pattern of cell divisions leads to the repeated generation of cells indistinguishable (by both light and electron microscopy) from those produced after the same division or pattern of cell divisions in the wild-type. This correlation between lineage history and cell fate suggests that in C. elegans a particular sequence of cell divisions may be necessary for the generation of a particular cell type. Reiterative lineages, often referred to as stem cell lineages, may be basic to the development of nematodes and other organisms. We suggest that the wild-type unc-86 and lin-4 genes act to modify latent reiterative cell lineages, which are revealed when the activity of one of these genes is eliminated. ------------------- Key: 508 Medline: 81240715 Authors: Hecht RM;Schomer DF;Oro JA;Bartel AH;Hungerford III EV Title: Simple adaptations to extend the range of flow cytometry five orders of magnitude for DNA analysis of uni- and multicell systems. Citation: Journal of Histochemistry & Cytochemistry 29: 771-774 1981 Type: ARTICLE Genes: Abstract: Procedures and instrumentation are described to extend the capability of a cytometry system to record samples that exhibit a wide range of fluorescence such as multicellular systems. The methods employs a log amplifier in combination with a set of neutral density filters that reduces the incident light reaching the photomultiplier tube. With any given filter, signals within an intensity range of 200-fold can be measured; different filters can be used to obtain an extended overall range. Polystyrene fluorescent microspheres and a variety of mithramycin stained biological samples ranging from yeast cells to Paramecium were processed by the system. The relative DNA content of individual multicellular embryos was determined for a heterogeneous population of embryonic stages isolated from the nematode, Caenorhabditis elegans. As part of the evaluation of the procedure, the practical upper limit of range extension was determined. The most intense fluorescent signal was produced when untreated pecan pollen stained with ethidium bromide fluoresced with a factor (8.4 +/- 1.3) x 10*4 more than ethidium bromide stained with E. coli cells. ------------------- Key: 509 Medline: 81220935 Authors: MacLeod AR;Karn J;Brenner S Title: Molecular analysis of the unc-54 myosin heavy-chain gene of C. elegans. Citation: Nature 291: 386-390 1981 Type: ARTICLE Genes: unc-54 Abstract: The properties of a small internal deletion mutant, E675, have been exploited in the molecular cloning of the unc-54 gene. This mutation uniquely identifies unc-54 sequences as molecules of altered length in E675 and provides a genetic and physical marker for the active gene, its messenger RNA and its protein product. ------------------- Key: 510 Medline: 81213193 Authors: Hecht RM;Gossett LA;Jeffery WR Title: Ontogeny of maternal and newly transcribed mRNA analyzed by in situ hybridization during development of C. elegans. Citation: Developmental Biology 83: 374-379 1981 Type: ARTICLE Genes: Abstract: In the present investigation we have examined the titer of poly(A) in squashes prepared from oocytes and variously staged embryos of the nematode Caenorhabditis elegans var. Bristol (N2) by in situ hybridization with a [3H]poly(U) probe. As shown by control experiments in which squashes were treated with dilute alkali and RNase prior to in situ hybridization, this probe interacts specifically with poly(A) sequences which are presumably present in poly(A)+ RNA. Using this method and saturating concentrations of the probe, it was shown that isolated oocytes and embryos up to the 125-cell stage exhibited substantial levels of poly(A) in their cytoplasms but no detectable amounts of this sequence within their nuclei. Nuclear poly(A) was first detected at the 90-cell stage and afterward increased at a linear rate through the 550-cell stage. The titer of total embryonic poly(A) also increased at a linear rate up to larval hatching. The results suggest that the major transcriptional effort for poly(A)+ RNA begins at the 90- to 125-cell stage of C. elegans embryogenesis and that the poly(A)+ RNA present in the cytoplasm prior to this time is primarily of maternal origin. ------------------- Key: 511 Medline: Authors: Cox GN;Kusch M;DeNevi K;Edgar RS Title: Temporal regulation of cuticle synthesis during development of C. elegans. Citation: Developmental Biology 84: 277-285 1981 Type: ARTICLE Genes: fer-1 Abstract: The pattern of cuticle protein synthesis during development of the nematode Caenorhabditis elegans has been studied using NaH(14)CO3. Both pulse-labeling and pulse-chase-labeling experiments indicate that synthesis of cuticle components occurs at high levels during the molting periods and at much reduced rates during the intermolt periods. No such discontinuous pattern is observed for the synthesis of total noncuticle macromolecules during development. The soluble and insoluble proteins of the cuticle, which comprise the inner and outer cuticle layers, respectively, follow similar patterns of synthesis during the two molts examined. At each molt the structural components of the cuticle account for approximately 10% of the total macromolecules labeled by NaH(14)CO3. No evidence is found for reuse of cuticle material between successive developmental stages of C. elegans. ------------------- Key: 512 Medline: Authors: Klass MR;Hirsh D Title: Sperm isolation and biochemical analysis of the major sperm protein from C. elegans. Citation: Developmental Biology 84: 299-312 1981 Type: ARTICLE Genes: him-1 him-8 Abstract: In order to facilitate the biochemical analysis of spermatogenesis in the nematode Caenorhabditis elegans methods have been developed for obtaining large quantities of males and for the isolation of sperm. Males are isolated by a passive filtration method from strains producing high proportions of males and sperm are isolated by physical pressure followed by filtration and differential centrifugation. Biochemical analyses show that sperm contain a major protein component that represents 17% of the total sperm protein. This protein has a molecular weight of 15,600, an isoelectric pH of 8.6, and exists as a dimer. It is shown by immunocytochemical techniques to be a specific product of spermatogenesis. It is localized in the proximal arm of the male gonad and in the sperm of both the male and hermaphrodite but it is not detected in other tissues of the nematode. It is not a nuclear binding protein. Pulse-labeling studies show that this major sperm protein is first synthesized in the proximal arm of the male gonad beginning at 39-42 hr after hatching at 20C. Poly(A) mRNA coding for this protein is first detected in a translatable form just before synthesis of this sperm protein suggesting transcriptional control. ------------------- Key: 513 Medline: 82005153 Authors: Johnson CD;Duckett JG;Culotti JG;Herman RK;Meneely PM;Russell RL Title: An acetylcholinesterase-deficient mutant of the nematode C. elegans. Citation: Genetics 97: 261-279 1981 Type: ARTICLE Genes: ace-1 ace-2 lon-1 mec-4 osm-1 unc-1 unc-3 unc-7 unc-24 unc-64 mnDf4 mnDf8 mnDp1 mnDp8 mnDp9 mnDf41 mnDf42 mnDp25 mnDp27 Abstract: Within a set of five separable molecular forms of acetylcholinesterase found in the nematode Caenorhabditis elegans, previously reported differences in kinetic properties identify two classes, A and B, likely to be under separate genetic control. Using differences between these classes in sensitivity to inactivation by sodium deoxycholate, a screening procedure was devised to search for mutants affected only in class A forms. Among 171 previously isolated behavioral and morphological mutant strains examined by this procedure, one (PR946) proved to be of the expected type, exhibiting a selective deficiency of class A acetylcholinesterase forms. Although originally isolated because of its uncoordinated behavior, this strain was subsequently shown to harbor mutations in two genes; one in the previously identified gene unc-3, accounting for its behavior, and one in a newly identified gene, ace-1, accounting for its selective acetylcholinesterase deficiency. Derivatives homozygous only for the ace-1 mutation also lacked class A acetylcholinesterase forms, but were behaviorally and developmentally indistinguishable from wild type. The gene ace-1 has been mapped near the right end of the X chromosome. Gene dosage experiments suggest that it may be a structural gene for a component of class A acetylcholinesterase forms. ------------------- Key: 514 Medline: 82005154 Authors: Culotti JG;von Ehrenstein G;Culotti MR;Russell RL Title: A second class of acetylcholinesterase-deficient mutants of the nematode C. elegans. Citation: Genetics 97: 281-305 1981 Type: ARTICLE Genes: ace-1 ace-2 unc-11 unc-35 unc-38 unc-57 unc-63 unc-73 unc-74 unc-89 Abstract: In JOHNSON et al. (1981), the Caenorhabditis elegans mutant strain PR1000, homozygous for the ace-1 mutation p1000, is shown to be deficient in the class A subset of acetylcholinesterases, which comprises approximately one-half of the total C. elegans acetylcholinesterase activity. Beginning with this strain, we have isolated 487 new behavioral and morphological mutant strains. Two of these, independently derived, lack approximately 98% of the wild-type acetylcholinesterase activity and share the same specific uncoordinated phenotype; both move forward in a slow and uncoordinated manner, and when mechanically stimulated to induce reversal, both hypercontract and become temporarily paralyzed. In addition to the ace-1 mutation, both strains also harbor recessive mutations in the same newly identified gene, ace-2, which maps to chromosome I and is therefore not linked to ace-1. Gene dosage experiments suggest that ace-2 is a structural gene for the remaining class B acetylcholinesterases, which are not affected by ace-1.--The uncoordinated phenotype of the newly isolated, doubly mutant strains depends on both the ace-1 and ace-2 mutations; homozygosity for either mutation alone produces normally coordinated animals. This result implies functional overlap of the acetylcholinesterases controlled by ace-1 and ace-2, perhaps at common synapses. Consistent with this, light microscopic histochemical staining of permeabilized whole mounts indicates some areas of possible spatial overlap of these acetylcholinesterases (nerve ring, longitudinal nerve cords). In addition, there is at least one area where only ace-2-controlled acetylcholinesterase activity appears (pharyngeo-intestinal ------------------- Key: 515 Medline: 82005155 Authors: Waterston RH Title: A second informational suppressor, sup-7 X, in C. elegans. Citation: Genetics 97: 307-325 1981 Type: ARTICLE Genes: dpy-18 sup-5 sup-7 unc-13 unc-15 unc-52 Abstract: More than 30 independent suppressor mutations have been obtained in the nematode C. elegans through reversion analysis of two unc-13 mutants. Many of the new isolates map to the region of the previously identified informational suppressor, sup-5 III (WATERSTON and BRENNER 1978). Several of the other suppressor mutations map to the left half of the X-linkage group and define a second suppressor gene, sup-7 X. In tests against 40 mutations in six genes, the sup-7(st5) allele was found to suppress to a greater extent the same alleles acted on by sup-5(e1464). Like sup-5(e1464), sup-7(st5) acts on null alleles of the myosin heavy-chain gene unc-54 I (MACLEOD et al. 1977; MACLEOD, WATERSTON and BRENNER 1977) and the putative paramyosin gene unc-15 I (WATERSTON et al. 1977). Chemical analysis of unc-15(e1214); sup- 7(st5) animals show that paramyosin is restored to more than 30% of the wild-type level.--As was observed for sup-5(e1464), suppression by sup-7(st5) is dose dependent and is greater in animals grown at 15 degrees than at 25 degrees. However, associated with this increased suppression is a decreased viability of sup-7(st5) homozygotes. Reversion of the lethality has resulted in the isolation of deficiency mutations that complement st5 lethality, but lack suppressor function. These properties of sup-7(st5) suggest that it, like sup-5(e1464), is an information suppressor of null alleles, and its reversion via deficiencies further narrows the possible explanations of its action. ------------------- Key: 516 Medline: 82078058 Authors: Files JG;Hirsh D Title: Ribosomal DNA of C. elegans. Citation: Journal of Molecular Biology 149: 223-240 1981 Type: ARTICLE Genes: Abstract: We have characterized the organization of the genes encoding for 18 S, 5.8 S and 26 S ribosomal RNAs in the nematode Caenorhabditis elegans. These ribosomal genes, present in about 55 copies per haploid genome, alternate in a repeating tandem array. The repeating unit is only 7000 base-pairs, containing a nontranscribed spacer of no more than 1000 base-pairs. Most of the repeating units have identical restriction maps, but one repeat contains a delection of 2900 base-pairs, which eliminates all or part of the 18 S coding region. We have found no difference in the major ribosomal DNA restriction endonuclease cleavage patterns between two interbreeding strains of C. elegans, but found differences between C. elegans and the closely related Caenorhabditis briggsae. ------------------- Key: 517 Medline: 81239808 Authors: Cox GN;Kusch M;Edgar RS Title: Cuticle of C. elegans: Its isolation and partial characterization. Citation: Journal of Cell Biology 90: 7-17 1981 Type: ARTICLE Genes: fer-1 him-8 Abstract: The adult cuticle of the soil nematode, Caenorhabditis elegans, is a proteinaceous extracellular structure elaborated by the underlying layer of hypodermal cells during the final molt in the animal's life cycle. The cuticle is composed of an outer cortical layer connected by regularly arranged struts to an inner basal layer. The cuticle can be isolated largely intact and free of all cellular material by sonication and treatment with 1% sodium dodecyl sulfate (SDS). Purified cuticles exhibit a negative material in the basal cuticle layer. The cuticle layers differ in their solubility in sulfhydryl reducing agents, susceptibility to various proteolytic enzymes and amino acid composition. The struts, basal layer, and internal cortical layer are composed of collagen proteins that are extensively cross-linked by disulfide bonds. The external cortical layer appears to contain primarily noncollagen proteins that are extensively cross- linked by nonreducible covalent bonds. The collagen proteins extracted from the cuticle with a reducing agent can be separated by SDS-polyacrylamide gel electrophoresis into eight major species differing in apparent molecular weight. ------------------- Key: 518 Medline: 81270494 Authors: Babu P;Brenner S Title: Spectrum of 32P-induced mutants of C. elegans. Citation: Mutation Research 82: 269-273 1981 Type: ARTICLE Genes: unc-17 unc-22 Abstract: Mutants of the free living nematode C. elegans were isolated by using 32P as a mutagen. It is shown that most of these mutants arise from 32P suicide. A comparison of EMS-induced and 32P-induced autosomal recessive mutations shows that there are no large regions of C. elegans genome which are protected from chemical mutagenic action of EMS. ------------------- Key: 520 Medline: Authors: Yeargers E Title: Effect of gamma-radiation on dauer larvae of C. elegans. Citation: Journal of Nematology 13: 235-237 1981 Type: ARTICLE Genes: Abstract: Caenorhabditis elegans is an ideal organism for studying the process of aging. It is easy to culture and has a short lifespan and specific aging symptoms. At 20 C the adult, reproductive stage occurs about 3 d after hatching; 4 d later egg laying ceases and degenerative changes begin. Death occurs about 10 d later. The postdauer lifetime is independent of the duration of the dauer stage of less than 60d; this suggests that dauer larvae do not age. The purpose of this study was to examine the notion that the lack of aging in dauer larvae is due to an intrinsic resistance to environmental stress, specifically ionizing radiation. ------------------- Key: 521 Medline: Authors: Bollinger JA;Willett JD Title: A method for synchrony of adult C. elegans. Citation: Nematologica 26: 491-493 1980 Type: ARTICLE Genes: Abstract: There are two ways of obtaining populations of adults from cultures of nematodes. The first is to treat juveniles with an inhibitor of DNA synthesis or shift them to a higher culture temperature to prevent subsequent reproduction. The second is to separate the adults from juveniles by settling. Inhibitors of DNA synthesis are non-specific and high temperatures may damage the nematodes. Therefore, the second method is preferable. This paper describes a method that uses settling and filtration to obtain synchronized populations of adults in sufficient quantity for life history studies. ------------------- Key: 522 Medline: Authors: Khan FR;McFadden BA Title: A rapid method of synchronizing developmental stages of C. elegans. Citation: Nematologica 26: 280-282 1980 Type: ARTICLE Genes: Abstract: Biochemical studies of the free-living nematode C. elegans require large numbers grown axenically and synchronously. Patel & MacFadden developed a procedure using alkali at 25C to axenize cultures of C. elegans after which eggs were separated into three bands in a sucrose gradient, one of which contained eggs that hatched in 10-13 hrs yielding a synchronous culture. We now report an improvement which is faster, does not require density-gradient sedimentation and markedly increases hatchability. ------------------- Key: 523 Medline: 82028246 Authors: Cox GN;Staprans S;Edgar RS Title: The cuticle of C. elegans. II. Stage-specific changes in ultrastructure and protein composition during postembryonic development. Citation: Developmental Biology 86: 456-470 1981 Type: ARTICLE Genes: daf-2 fer-1 lin-4 lin-14 Abstract: The cuticle of the free-living nematode Caenorhabditis elegans is a proteinaceous extracellular structure that is replaced at each of four postembryonic molts by the underlying hypodermis. The cuticles of the adult and three juvenile stages (L1, Dauer larva, L4) have been compared ultrastructurally and biochemically. Each cuticle has an annulated surface and comprises two main layers, an inner basal layer and an outer cortical layer. The adult cuticle has an additional clear layer which separates the basal and cortical layers and is traversed by regularly arranged columns of electron-dense material. The fine structure of the cortical layer is similar in cuticles from different stages while that of the basal layer is stage specific. Purified cuticles were obtained by sonication and treament with sodium dodecyl sulfate (SDS) and their component proteins solubilized with a sulfhydryl reducing agent. The degree of cuticle solubility is stage specific and the insoluble structures for each cuticle were localized by electron microscopy. Analysis of 35S-labeled soluble cuticle proteins by SDS-polyacrylamide gel electrophoresis yields unique banding patterns for each stage. Most proteins are of high molecular weight (100-200K) and are restricted to particular stages. Sixteen of the nineteen major proteins characterized are specifically degraded by bacterial collagenase. The results indicate that the different molts are not reiterative, but require the integration of both unique and shared gene functions. The potential use of stage-specific cuticle differences to identify and characterize regulatory genes controlling cuticle-type switching during development is discussed. ------------------- Key: 524 Medline: 82028281 Authors: Kimble J Title: Alterations in cell lineage following laser ablation of cells in the somatic gonad of C. elegans. Citation: Developmental Biology 87: 286-300 1981 Type: ARTICLE Genes: Abstract: The postembryonic cell lineage of the somatic gonad is essentially invariant in Caenorhabditis elegans. The two exceptions to this rule of invariance involve a natural ambiguity in the ancestry of certain cells such that each of the two precursor cells assumes one of two alternative fates in a given animal. In this paper, experiments are reported in which laser microsurgery is used to kill individual cells in the developing somatic gonad. Such intervention perturbs the normal environment of the remaining cells; a change observed in the expected behavior of these cells suggests that extrinsic cues may normally play a role in controlling that behavior. Several different lineage alterations have been observed after laser microsurgery in the somatic gonad. These include switches in the type of lineage followed by a given precursor cell, reversals in lineage polarity, duplications of a lineage, and alterations in the number of cells produced in the lineage. The only cases in which cells switch from one lineage type to another involve pairs of cells which exhibit natural ambiguity. In most cases, the interactions inferred from these changes seem to occur between neighboring somatic gonadal cells. In one case, induction of the vulva, the interaction occurs between a single somatic gonadal cell, the anchor cell, and the precursors to the vulva in a neighboring tissue, the hypodermis. The roles of intrinsic and extrinsic cues in ------------------- Key: 525 Medline: 82060653 Authors: Kimble JE Title: Strategies for control of pattern formation in C. elegans. Citation: Philosophical Transactions of the Royal Society of London 295B: 539-551 1981 Type: REVIEW Genes: Abstract: In this paper, strategies for controlling pattern formation in Caenorhabditis elegans are reviewed. The somatic tissues of this small nematode develop, in large part, by invariant cell lineages, whereas the germ-line tissue arises primarily by a variable pattern of divisions. The spatial organization of the germ-line tissue depends on special regulatory cells, the distal tip cells, which appear to influence nearby germ cells to remain in mitosis. In somatic tissues, the problem of specifying that a cell in a particular position assumes a particular fate seems to be controlled by a number of different strategies. These include the production of non-equivalent cells in particular positions of the lineage tree, local interactions between apparently equivalent cells in close contact, and the influence of another special regulatory cell, the anchor cell, over certain neighbouring cells. ------------------- Key: 526 Medline: Authors: Mounier N Title: Location of neurosecretory-like material in C. elegans. Citation: Nematologica 27: 160-166 1981 Type: ARTICLE Genes: Abstract: The distribution of neurosecretory-like material was investigated in C. elegans, var. Bergerac and Bristol by classical histochemical methods. No nerve cells of the anterior nervous system and the cords contained such material but the two gland cells in the excretory system possessed paraldehyde-fuschin positive granules. Fixation in osmium tetroxide and in hot chromic acid were essential before PF treatment. The nature of the granules and their role are discussed. ------------------- Key: 527 Medline: Authors: Russell RL Title: Mutants of neurotransmitter metabolism and action in the nematode C. elegans. Citation: "Genetic Research Strategies in Psychobiology and Psychiatry. Psychobiology and Psychopathology Volume I." Gershon ES, Matthysse S, Breakefield XO and Ciaranello RD (eds), Boxwood Press, Pacific Grove, CA. I: 113-128 1981 Type: REVIEW Genes: ace-2 cat-1 cat-2 cat-3 cat-4 cat-5 cha-1 unc-29 unc-38 unc-40 unc-63 unc-74 unc-86 Abstract: This chapter is in part a review of the work of others and in part a summary of recent results from our own laboratory. It attempts to cover the currently available information on apparent neurotransmitters in the small soil nematode Caenorhabditis elegans, whose advantages of genetic manipulability and cellular simplicity have recently gained it some favor in investigations of genetic control mechanisms in neural development (for review, see Riddle, 1978). Particular attention is given to mutants that affect either the level or the action of apparent neurotransmitters, since it seems likely that such mutants may have the most to offer toward the understanding of human genetic neuropathies. The general features of C. elegans are described briefly at the outset, then each apparent neurotransmitter is considered in turn, and finally a few potential implications for other organisms ------------------- Key: 528 Medline: 82028297 Authors: Sternberg PW;Horvitz HR Title: Gonadal cell lineages of the nematode Panagrellus redivivus and implications for evolution by the modification of cell lineage. Citation: Developmental Biology 88: 147-166 1981 Type: ARTICLE Genes: Abstract: To explore the nature of cell lineage modifications that have occurred during evolution, the gonadal cell lineages of the nematode Panagrellus redivivus have been determined and compared to the known gonadal lineages of Caenorhabditis elegans. Essentially invariant lineages generate the 143 somatic cells of the male gonad and at least 326 somatic cells of the female gonad of P. redivivus. The basic program of gonadogenesis is strikingly similar among both sexes of both species. For example, the early division patterns of the somatic gonad precursors Z1 and Z4 are almost identical. Later division patterns are more divergent and, in a few cases, generate structures that are species specific. In general, similar cell types are produced after similar patterns of cell divisions. Differences among Z1 and Z4 cell lineages appear to reflect phylogenetic modifications of a common developmental program. The nature of these differences suggests that the evolution of cell lineages involves four distinct classes of alterations: switches in the fate of a cell to that normally associated with another cell; reversals in the polarity of the lineage generated by a blast cell; alterations in the number of rounds of cell division; and an "altered segregation" of developmental potential, so that a potential normally associated with one cell instead becomes associated with its sister. A number of cell deaths occur during gonadogenesis in P. redivivus. The death of Z4.pp, a cell that controls the development of the posterior ovary in C. elegans, probably prevents the development of a posterior ovary in P. redivivus and hence is responsible for the gross differences in the morphologies of the gonads of the P. redivivus female and the C. elegans hermaphrodite. As exemplified by the death of Z4.pp, an alteration in the fate of a "regulatory cell" could facilitate rapid and/or discontinous evolutionary ------------------- Key: 529 Medline: 82053219 Authors: Ward S;Argon Y;Nelson GA Title: Sperm morphogenesis in wild-type and fertilization-defective mutants of C. elegans. Citation: Journal of Cell Biology 91: 26-44 1981 Type: ARTICLE Genes: fer-1 fer-2 fer-3 fer-4 fer-6 Abstract: Taking advantage of conditions that allow spermatogenesis in vitro, the timing and sequence of morphological changes leading from the primary spermatocyte to the spermatozoon is described by light and electron microscopy. Together with previous studies, this allows a detailed description of the nuclear, cytoplasmic, and membrane changes occurring during spermatozoan morphogenesis. By comparison with wild type, abnormalities in spermatogenesis leading to aberrant infertile spermatozoa are found in six fertilization-defective (fer) mutants. In fer-1 mutant males, spermatids appear normal, but during spermiogenesis membranous organelles (MO) fail to fuse with the sperm plasma membrane and a short, though motile. pseudopod is formed. In fer-2, fer-3, and fer-4 mutants, spermatids accumulate 48-nm tubules around their nuclei where the centriole and an RNA containing perinuclear halo would normally be. In all three mutants, spermatids still activate to spermatozoa with normal fusion of their MOs, but the pseudopods formed are aberrant in most fer-2 and fer-4 spermatozoa and in some fer-3 spermatozoa. In fer-5 mutant males, spermatozoa do not form. Instead, defective spermatids with crystalline inclusions and abnormal internal laminar membranes accumulate. In fer-6 mutant males, only a few spermatozoa form and these have defective pseudopods. These spermatozoa retain their fibrous bodies, a structure which normally disassembles in the spermatid. The time of appearance of developmental abnormalities in all of these mutants correlates with the temperature-sensitive periods for development of infertility. The observation that each of these mutants has a different and discreet set of morphological defects, a structure which normally disassembles in the spermatid. The time of appearance of developmental abnormalities in all of these mutants correlates with the temperature-sensitive periods for development of infertility. The observation that each of these mutants has a different and discreet set of morphological defects, a structure which normally disassembles in the spermatid. The time of appearance of developmental abnormalities in all of these mutants correlates with the temperature-sensitive periods for development of infertility. The observation that each of these mutants has a different and discreet set of morphological defects shows that the strict sequence of morphogenetic events that occurs during wild-type spermatogenesis cannot arise because each event is dependent on previous events. Instead, spermatozoa, like bacteriophages, must be formed by multiple independent pathways of morphogenesis. ------------------- Key: 530 Medline: 82089292 Authors: Rand JB;Johnson CD Title: A single-vial biphasic liquid extraction assay for choline acetyltransferase using [3H]choline. Citation: Analytical Biochemistry 116: 361-371 1981 Type: ARTICLE Genes: Abstract: A single-vial liquid extraction assay for choline acetyltransferase that uses [3H]choline as the labeled substrate has been devised. [3H]Choline is incubated with an excess of acetyl-CoA in a small reaction vial which also serves as a scintillation vial. After a suitable reaction period, unreacted [3H]choline is quickly and quantitatively converted to phosphoryl-[3H]choline by the addition of an excess of choline kinase. This treatment is followed by the addition of scintillation fluid containing sodium tetraphenylboron after which the vial is capped, shaken, and counted. A two-phase system is produced in which product [3H]acetylcholine is selectively extracted into the scintillation fluid, where it is counted. Phosphoryl-[3H]choline remains in the aqueous phase and is not counted. This assay is rapid, simple, and quite sensitive. In comparison to assays using acetyl-CoA as the labeled substrate, it is less sensitive to interference by other enzymes and thus more suitable for measuring choline acetlytransferase in crude extracts and in the initial stages of purification. Similar single-vial radiometric assays are described for choline kinase and acetyl-CoA hydrolases. ------------------- Key: 531 Medline: Authors: Wright KA;Thomson JN Title: The buccal capsule of C. elegans (Nematoda: Rhabditoidea): An ultrastructural study. Citation: Canadian Journal of Zoology 59: 1952-1961 1981 Type: ARTICLE Genes: Abstract: The buccal cavity of the free-living nematode Caenorhabditis elegans has been analysed by serial section electron microscopy. Whereas the regions classically identified in the rhabditid buccal capsule can be distinguished, the cuticle lining does not constitute separate cuticular plates, but rather, structural-functional differentiations within a cuticle continuous with that of the esophagus. Only the lip region (cheilostom) is lined by body wall cuticle. The prostom cuticle is underlain by two rings of syncytial arcade cytoplasm connected to nine cell bodies. The mesostom cuticle is underlain by the nonmuscular epithelial cells of the esophagus, whereas the cuticle of the metastom and telostom is underlain by esophageal muscle cells m1 and m2. During moulting, buccal cuticle is produced later than body cuticle and its formation is characterized by accumulation of dense granules in both arcade and esophageal cytoplasm. It is concluded that the buccal capsule should be considered as "astomatous" in the terminology of K.A. ------------------- Key: 532 Medline: 82024235 Authors: Ouazana R;Herbage D Title: Biochemical characterization of the cuticle collagen of the nematode C. elegans. Citation: Biochimica et Biophysica Acta 669: 236-243 1981 Type: ARTICLE Genes: Abstract: Proteins of purified cuticles from adults of the small free-living nematode Caenorhabditis elegans are solubilized by reduction in the presence of a strong denaturing agent and then carboxymethylated. As in the large parasitic nematode Ascaris lumbricoides, these soluble proteins appeared to be collagens by their amino acid compositions. C. elegans cuticle collagen is separated into seven major components with different apparent molecular weights by molecular sieve chromatography and sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The two main components, which together account for more than 64% of the total cuticle collagen, were extracted from gel after electrophoresis and analyzed. They differ in their amino acid compositions and would seem to represent genetically distinct collagen chains. The results presented lead to the hypothesis of the presence in this collagen of at least two different chains. ------------------- Key: 533 Medline: 81098344 Authors: Siddiqui SS;Babu P Title: Kynurenine hydroxylase mutants of the nematode C. elegans. Citation: Molecular & General Genetics 179: 21-24 1980 Type: ARTICLE Genes: flu-1 Abstract: The relation of intestinal autofluorescence to tryptophan catabolism in the free-living nematode Caenorhabditis elegans has been investigated. L-Kynurenine hydroxylase (EC 1.14.13.9) activity has been detected in normal (wild-type) individuals. Mutants in the gene flu-1 which are characterized by an altered autofluorescence of the intestine cells, i.e., more intense than wild type and bluish purple instead of light blue have also been examined. They show a markedly reduced activity of kynurenine hydroxylase. The finding supports the previously proposed model for altered fluorescence based on chromatographic identification of tryptophan catabolites ------------------- Key: 534 Medline: 82185819 Authors: Goldstein P;Slaton DE Title: The synaptonemal complexes of C. elegans: Comparison of wild-type and mutant strains and pachytene karyotype analysis of wild-type. Citation: Chromosoma 84: 585-597 1982 Type: ARTICLE Genes: him-8 Abstract: Normal synaptonemal complexes (SCs), consisting of two lateral elements and a central element, are present in wild-type, him-4 and him-8 mutant strains in both hermaphrodites and males of caenorhabditis elegans. Thus, the increase in rate of nondisjunction in the him mutants is not related to aberrant SC morphology. The wild- type hermaphrodite has six SCs, as determined from 3-D reconstruction analysis of serial section from electron microscopy. Thus, n=6 and this confirms early reports based on cytological studies with the light microscope. Only one end of the SC is attached to the nuclear envelope while the other end is free in the nucleoplasm and there is no apparent bouquet formation. Either end of the SC can attach to the nuclear envelope. The pairing behavior of the XX bivalent is normal and occurs synchronously with the autosomes. Electron dense bodies, or knobs, are associated with the SC via the central element and displace the chromatin for a distance of 200 nm. Each pachytene nucleus of the wild-type hermaphrodite has six such structures that are randomly dispersed along the bivalents such that some SCs have one or two knobs while others have none. Their function is unknown. ------------------- Key: 535 Medline: 82145562 Authors: Butler MH;Wall SM;Luehrsen KR;Fox GE;Hecht RM Title: Molecular relationships between closely related strains and species of nematodes. Citation: Journal of Molecular Evolution 18: 18-23 1981 Type: ARTICLE Genes: Abstract: Electrophoretic comparisons have been made for 24 enzymes in the Bergerac and Bristol strains of Caenorhabditis elegans and the related species, Caenorhabditis briggsae. No variation was detected between the two strains of C. elegans. In contrast, the two species, C. elegans and C. briggsae exhibited electrophoretic differences in 22 of 24 enzymes. A consensus 5S rRNA sequence was determined for C. elegans and found to be identical to that from C. briggsae. By analogy with other species with relatively well established fossil records it can be inferred that the time of divergence between the two nematode species is probably in the tens of millions of years. The limited anatomical evolution during a time period in which proteins undergo extensive changes supports the hypothesis that anatomical evolution is not dependent on overall protein ------------------- Key: 536 Medline: 82120291 Authors: Nelson GA;Roberts TM;Ward S Title: C. elegans spermatozoan locomotion: Amoeboid movement with almost no actin. Citation: Journal of Cell Biology 92: 121-131 1982 Type: ARTICLE Genes: fer-2 unc-15 unc-22 unc-23 unc-45 unc-52 unc-60 unc-78 unc-82 unc-87 unc-89 unc-90 Abstract: The pseudopods of Caenorhabditis elegans spermatozoa move actively causing some cells to translocate when the sperm are dissected into a low osmotic strength buffered salts solution. On time-lapse video tapes, pseudopodial projections can be seen moving at 20-45 micrometers/min from the tip to the base of the pseudopod. This movement occurs whether or not the cell is attached to a substrate. Translocation of the cell is dependent on the substrate. Some spermatozoa translocate on acid-washed glass, but a better substrate is prepared by drying an extract of Ascaris uteri (the normal site of nematode sperm motility) onto glass slides. On this substrate more than half the spermatozoa translocate at a velocity (21 micrometers/min) similar to that observed in vivo. Translocating cells attach to the substrate by their pseudopodial projections. They always move toward the pseudopod; changes in direction are caused by changes in pseudopod shape that determine points of detachment and reattachment of the cell to the substrate. Actin comprises less than 0.02% of the proteins in sperm, and myosin is undetectable. No microfilaments are found in the sperm. Immunohistochemistry shows that some actin is localized in patches in the pseudopod. The movement of spermatozoa is unaffected by cytochalasins, however, so there is no evidence that actin participates in locomotion. Fertilization-defective mutants in genes fer-2, fer-4, and fer-6 produce spermatozoa with defective pseudopodial projections, and these spermatozoa are largely immotile. Mutants in the spermatozoa do not translocate. Thus pseudopod movement is correlated with the presence of normal projections. Twelve mutants with defective muscles have spermatozoa with normal movement, so these genes do not specify products needed for both muscle and nonmuscle cell motility. ------------------- Key: 537 Medline: 82120292 Authors: Roberts TM;Ward S Title: Centripetal flow of pseudopodial surface components could propel the amoeboid movement of C. elegans spermatozoa. Citation: Journal of Cell Biology 92: 132-138 1982 Type: ARTICLE Genes: fer-1 fer-2 Abstract: Latex beads and wheat germ agglutinin (WGA) were used to examine the movement of membrane components on amoeboid spermatozoa of Caenorhabditis elegans. The behavior of beads attached to the cell revealed continuous, directed movement from the tip of the pseudopod to its base, but no movement on the cell body. Lectin receptors are also cleared from the pseudopod (4). Blocking preexisting lectin receptors with unlabeled WGA followed by pulse-labeling wih fluorescent WGA showed that new lectin receptors are continuously inserted at the tip of the pseudopod. Like latex beads, these new lectin receptors move continuously over the pseudopod surface to the cell body-pseudopod junction where they are probably internalized. Mutants altering the rate of membrane flow, and eliminating its topographical asymmetry, have been identified. Together with the observation that fluorescent phospholipids are cleared from the pseudopod of developing spermatozoa at the same rate as lectin receptors (25), these results show that there is bulk membrane flow over the pseudopod with assembly at the tip and apparent disassembly at the base. There are no vesicles visible at either the pseudopodial tip or base, so these spermatozoa must have a novel mechanism for insertion and uptake of membrane components. This membrane flow could provide the forward propulsion of spermatozoa attached to a substrate by their pseudopods. ------------------- Key: 538 Medline: 82140057 Authors: Fodor A;Deak P;Kiss I Title: Competition between juvenile hormone antagonist precocene II and juvenile hormone analog: Methoprene in the nematode C. elegans. Citation: General & Comparative Endocrinology 46: 99-109 1982 Type: ARTICLE Genes: che-1 che-2 dpy-11 lev-1 lev-8 lon-2 unc-3 Abstract: Precocene II causes a high adult mortality and a drastic growth reduction of growing Caenorhabditis elegans larvae. Symptoms caused by precocene II were partly reversible by the insect juvenile hormone analog methoprene, suggesting a physiological role of juvenile hormones in nematodes. ------------------- Key: 539 Medline: 82197609 Authors: Ciliberto G;Traboni C;Cortese R Title: Relationship between the two components of the split promoter of eukaryotic tRNA genes. Citation: Proceedings of the National Academy of Sciences USA 79: 1921-1925 1982 Type: ARTICLE Genes: Abstract: Plasmids containing eukaryotic tRNA genes are faithfully transcribed in the nucleus of Xenopus laevis oocytes. It has been established that two separated regions within the coding sequence of a tRNA gene are essential and sufficient for the promotion of transcription. We have constructed a hybrid tRNA gene containing one essential region from tDNA*Leu and the other from tDNA*Pro, both from Caenorhabditis elegans. This hybrid gene is efficiently transcribed, thus showing that the essential regions are independent transcriptional signals regardless of overall regularities of the structure of tRNA genes. We have also constructed mutants of the tRNA*Pro gene in which the distance between the two essential regions is changed; optimal transcription occurs when this distance is about 40-50 nucleotides. ------------------- Key: 540 Medline: 82174562 Authors: Ciliberto G;Castagnoli L;Melton DA;Cortese R Title: Promoter of a eukaryotic tRNApro gene is composed of three noncontiguous regions. Citation: Proceedings of the National Academy of Sciences USA 79: 1195-1199 1982 Type: ARTICLE Genes: Abstract: The 71-base-pair coding sequences of the tRNAPro gene from Caenorhabditis elegans contains all of the information required for transcription and processing in the injected oocytes. Several subclones of the DNA coding for the tRNAPro were constructed, carrying deletions or insertions, or both. Their transcriptional properties lead to the hypothesis that the tRNAPro gene promoter is composed of three discontinuous regions within the coding sequence. ------------------- Key: 541 Medline: 82174639 Authors: Strome S;Wood WB Title: Immunofluorescence visualization of germ-line-specific cytoplasmic granules in embryos, larvae, and adults of C. elegans. Citation: Proceedings of the National Academy of Sciences USA 79: 1558-1562 1982 Type: ARTICLE Genes: Abstract: By using fluorescent antibody staining, we have followed cytoplasmic granules unique to germ-line cells throughout the life cycle of Caenorhabditis elegans. These elements, designated P granules, are segregated exclusively to germ-line precursor cells during early embryogenesis. Prior to mitosis at each of the early cleavages that produce a somatic and germ-line daughter cell, the granules become localized in the region of cytoplasm destined for the germ-line daughter. After the 16-cell stage, the granules appear to be associated with the nuclear envelope. P granules persist in the germ cells throughout the larval and adult stages. The P granules are similar in number, size, and distribution to germ-line-specific structures identified as "germinal plasm" by electron microscopy in C. elegans embryos. ------------------- Key: 542 Medline: 82055726 Authors: Mackenzie JM Jr;Epstein HF Title: Electron microscopy of nematode thick filaments. Citation: Journal of Ultrastructure Research 76: 277-285 1981 Type: ARTICLE Genes: Abstract: Thick filaments have been isolated from the body-wall muscle cells of the nematode Caenorhabditis elegans. Their protein constituents were shown by SDS-polyacrylamide gel electrophoresis to be myosin, paramyosin, several previously unidentified protein bands and small amounts of actin and tropomyosin from contaminating thin filaments. These thick filaments have been studied by electron microscopy using two different methods of preparation: (a) unfixed filaments, negatively stained with uranyl acetate and (b) glutaraldehyde-fixed filaments, critical-point dried and shadowed with platinum-carbon. The latter method has permitted resolution of crossbridges in many different orientations about the cylindrical shaft of the thick filament. These observations support the hypothesis that the myosin crossbridges are flexibly connected to myosin rods within muscle thick filaments. Myosin heads were visualized in individual nematode myosin oligomers. The morphology and dimensions of the myosin heads are very similar to those of the crossbridge in the native filaments. Our results present a direct visual demonstration of the flexible arrangement of crossbridges with respect to the cylindrical backbones of structurally intact thick filaments. ------------------- Key: 543 Medline: Authors: Cassada R;Isnenghi E;Denich K;Radnia K;Schierenberg E;von Ehrenstein G Title: Genetic dissection of embryogenesis in C. elegans. Citation: "Developmental Biology Using Purified Genes" ICN-UCLA Symposia on Molecular and Cellular Biology, Volume 23. Brown DD (ed), Academic Press, NY. 23: 209-227 1981 Type: REVIEW Genes: emb-1 emb-2 emb-3 emb-4 emb-5 emb-6 emb-7 emb-8 emb-9 emb-10 emb-11 emb-12 emb-13 emb-14 emb-15 emb-16 emb-17 emb-18 emb-19 emb-20 emb-21 emb-22 emb-23 emb-24 emb-25 emb-26 emb-27 emb-28 emb-29 emb-30 emb-31 emb-32 emb-33 emb-34 emb-35 let-2 zyg-1 zyg-2 zyg-3 zyg-7 zyg-8 zyg-9 Abstract: The complex process of embryogenesis in the simple nematode Caenorhabditis elegans is invariant from animal to animal. Cell lineages have been studied by direct observation of individual cells in living embryos using Nomarski differential-interference-contrast microscopy. To dissect events genetically involved in embryogenesis, we have isolated a set of 36 recessive temperature-sensitive (ts) mutants in 30 separate emb-genes, which cause arrest of embryonic development. The fraction of emb mutants among total ts lethals and the recurrence frequency (second alleles) allowed two independent estimates of 200-500 genes essential for embryogenesis (of a total of about 2000 essential genes). So far 54 emb genes have been detected, still far from genetic saturation. We have mapped 25 new emb genes (resolution of 1 recombination unit). Surprisingly, 10 emb genes are clustered near gene unc-32 on linkage group III. Higher resolution mapping here, using deletions, is under way. We have tested the mode of expression (the necessity and/or sufficiency for normal embryogenesis) of the wild-type alleles of these 30 genes in the parents and zygote by performing genetic crosses in which a wild-type allele appears in various configurations, and then determining at the restrictive temperature (25C) the effect on the viability of the resulting progeny genotypes. A majority of the emb genes are of maternal-expression-necessary class (18 of 30 genes studied), in agreement with the results from other similar mutants. For 3 genes, neither maternal nor zygotic expression is sufficient (both necessary?). We have also found 2 zygotic-necessary-and-sufficient genes. For 1 gene paternal expression is partially sufficient. The remaining 7 are of the parental-or-zygotic-expression-sufficient class. We have ordered the ts mutants sequentially in development by temperature shift experiments and according to their arrest stage (terminal phenotypes). Their cellular and subcellular properties are being studied to identify the cellular processes defective in the mutants, and ultimately the mechanisms for genetic control of cell behavior in embryogenesis. We are finding a variety of defects in early cell lineages, including the timing of embryonic cell divisions similar to those already described in another set of mutants. ------------------- Key: 544 Medline: Authors: Edgar RS;Cox GN;Kusch M;Politz JC Title: The cuticle of C. elegans. Citation: Journal of Nematology 14: 248-258 1982 Type: REVIEW Genes: lin-4 lin-14 Abstract: The nematode cuticle is among the most complex extracellular structures produced by a living organism. For the last few years the work in our laboratory has been devoted to the study of the cuticle of the free-living nematode, Caenorhabditis elegans. Studies so far largely have been of a descriptive nature, involving attempts to characterize the morphology and composition of the cuticle and to isolate and study mutants altered in genes that control and regulate cuticle formation. Our long-term interest is to understand the genetic control and regulation of complex processes such as cuticle formation. ------------------- Key: 545 Medline: Authors: Ward S;Roberts TM;Nelson GA;Argon Y Title: The development and motility of C. elegans spermatozoa. Citation: Journal of Nematology 14: 259-266 1982 Type: REVIEW Genes: fer-1 fer-2 Abstract: Nematode sperm have puzzled zoologists for nearly a century because they are not flagellated. Their morphology is amoeboid, but there have been only a few descriptions of their actual movement. We have undertaken an intensive examination of the spermatozoa of Caenorhabditis elegans in order to learn how they develop their specialized morphology. This nematode was chosen because it is easily cultured in the laboratory and it has become the subject of detailed studies of its genetics, development, and behavior. In this paper we summarize our recent results which demonstrate that these spermatozoa have a novel mechanism of amoeboid motility. ------------------- Key: 546 Medline: Authors: Wood WB;Laufer JS;Strome S Title: Developmental determinants in embryos of C. elegans. Citation: Journal of Nematology 14: 267-273 1982 Type: REVIEW Genes: Abstract: C. elegans is proving uuseful for the study of cell determination in early embryos. Breeding experiments with embryonic lethal mutants show that abnormal embryogenesis often results from defective gene function in the maternal parent, suggesting that much of the information for normal embryonic development is laid down during oogenesis. Analysis of a gut-specific differentiation marker in cleavage-arrested embryos has provided evidence that the potential for this differentiation behaves as a cell-autonomous internally segregating developmental determinant, which is present at the 2-cell stage onward and is partitioned into the gut precursor cell during early cleavage divisions. Visible prelocalized cytoplasmic granules that segregate with a particular cell lineage have been observed in the embryonic germline precursor cells by fluorescent antibody staining. Whether these granules play a role in germline determina... ------------------- Key: 547 Medline: Authors: Riddle DL Title: Developmental biology of C. elegans: Symposium Citation: Journal of Nematology 14: 238-239 1982 Type: REVIEW Genes: Abstract: Many nematologists do not seem to be interested in nematodes for the nematodes' sake, but instead are concerned primarily with the plants or animals they may parasitize and the economic importance of nematode control. Perhaps as a consequence of this and other factors, nematology has developed along paths which were, in a sense, long ago predetermined by the historical divisions between plant and animal scientists. Obviously, a crucial role for the Society in the development of nematology as a scientific discipline is to bridge the natural gap that has been laid down by historical precedent. ------------------- Key: 548 Medline: Authors: Horvitz HR;Sternberg PW Title: Nematode postembryonic cell lineages. Citation: Journal of Nematology 14: 240-248 1982 Type: REVIEW Genes: Abstract: The complete postembryonic cell lineages of the free-living nematodes Caenorhabditis elegans and Panagrellus redivivus are known. Postembyronic cell divisions lead to substantial increases in the number of cells, and in most cases, in the number of types of cells in the neuronal, muscular, hypodermal, and digestive systems. The patterns of postembryonic cell divisions are essentially invariant and generate a fixed number of progeny cells of strictly specified fates. Cell fates depend upon both lineage history and cell-cell interactions: lineage limits the developmental potential of each cell and, for certain cells, cell-cell interactions specify which of a small number of alternative potential fates is acquired. Relatively simple differences in cell lineage account for some of the striking differences in gross morphology both between sexes and between species. Genetic studies indicate that these cell lineage differences reflect one or a few relatively simple mutational events. Interspecific differences in cell lineage are likely to be good indicators of evolutionary distance and may be helpful in defining taxonomic relationships. Both the techniques utilized in, and the information acquired from, studies of cell lineages in C. elegans and P. redivivus may prove useful to other nematologists. ------------------- Key: 549 Medline: 82176753 Authors: Lew KK;Chritton S;Blumberg PM Title: Biological responsiveness to the phorbol esters and specific binding of 3H phorbol 12, 13-dibutyrate in C. elegans, a manip gen sys/ Citation: Teratogenesis, Carcinogenesis & Mutagenesis 2: 19-30 1982 Type: ARTICLE Genes: Abstract: Because of its suitability for genetic studies, the nematode Caenorhabditis elegans was examined for its responsiveness to the phorbol esters. Phorbol 12-myristate 13-acetate had three effects. It inhibited the increase in animal size during growth; it decreased the yield of progeny; and it caused uncoordinated movement of the adult. The effects on nematode size, progeny yield, and movement were quantitated. Concentrations of phorbol 12-myristate 13-acetate yielding half-maximal responses were 440, 460, and 170 nM, respectively. As was expected from the biological responsiveness of the nematodes, specific, saturable binding of phorbol ester to nematode extracts was found. [3H]phorbol 12,13-dibutyrate bound with a dissociation constant of 26.8 +/- 3.9 nM. At saturation, 5.7 +/- 1.4 pmole/mg protein was bound. ------------------- Key: 550 Medline: 82167789 Authors: Chalfie M;Thomson JN Title: Structural and functional diversity in the neuronal microtubules of C. elegans. Citation: Journal of Cell Biology 93: 15-23 1982 Type: ARTICLE Genes: mec-7 Abstract: Tannic acid fixation reveals differences in the number of protofilaments between microtubules (MTs) in the nematode Caenorhabditis elegans. Most cells have MTs with 11 protofilaments but the six touch receptor neurons (the microtubule cells) have MTs with 15 protofilaments. No 13-protofilament (13-p) MT has been seen. The modified cilia of sensory neurons also possess unusual structures. The cilia contain nine outer doublets with A subfibers of 13 protofilaments and B subfibers of 11 protofilaments and a variable number of inner singlet MTs containing 11 protofilaments. The 15-p MTs but not the 11-p MTs are eliminated by colchicine-treatment or by mutation of the gene mec-7. Concomitantly, touch sensitivity is also lost. However, whereas colchicine treatment leads to the loss of all MTs from the microtubule cells, mutations in mec-7 result in the partial replacement of the 15-p MTs with 11-p MTs. Benzimidazoles (benomyl and nocodazole) have more general effects on C. elegans (slow growth, severe uncoordination, and loss of processes from the ventral cord) but do not affect the 15-p MTs. Benomyl will, however, disrupt the replacement 11-p MTs found in the microtubule cells of mec-7 mutants. The 11-p and 15-p MTs also respond differently to temperature and fixation conditions. It is likely that either type of MT will suffice for the proper outgrowth of the microtubule cell process, but only the 15-p MT can function in the specialized role of sensory transduction of the microtubule ------------------- Key: 551 Medline: Authors: Robertson AMG;Thomson JN Title: Morphology of programmed cell death in the ventral nerve cord of C. elegans larvae. Citation: Journal of Embryology & Experimental Morphology 67: 89-100 1982 Type: ARTICLE Genes: Abstract: In the nematode Caenorhabditis elegans, cells undergoing programmed cell death in the developing ventral nerve cord were identified by Nomarski optics and prepared for ultrastructural study at various times after their birth in mitosis. The sequence of changes observed suggests that the hypodermis recognizes the dying cell before completion of telophase. The dying cell is engulfed and digestion then occurs until all that remains within the hypodermal cytoplasm is a collection of membranous whorls interspersed with condensed chromatin-like remnants. The process shares several features with apoptosis, the mode of programmed cell death observed in vertebrates and insects. The selection of cells for programmed death appears not to involve competition for peripheral targets. ------------------- Key: 552 Medline: 82199429 Authors: Horvitz HR;Chalfie M;Trent C;Sulston JE;Evans PD Title: Serotonin and octopamine in the nematode C. elegans. Citation: Science 216: 1012-1014 1982 Type: ARTICLE Genes: che-3 daf-10 osm-3 unc-86 Abstract: The biogenic amines serotonin and octopamine are present in the nematode Caenorhabditis elegans. Serotonin, detected histochemically in whole mounts, is localized in two pharyngeal neurons that appear to be neurosecretory. Octopamine, identified radioenzymatically in crude extracts, probably is also localized in a few neurons. Exogenous serotonin and octopamine elicit specific and opposite behavioral responses in Caenorhabditis elegans, suggesting that these compounds function physiologically as antagonists. ------------------- Key: 554 Medline: 82211746 Authors: Rosenbluth RE;Baillie DL Title: The genetic analysis of a reciprocal translocation, eT1(III;V), in C. elegans. Citation: Genetics 99: 415-428 1981 Type: ARTICLE Genes: bli-5 dpy-1 dpy-5 dpy-11 dpy-17 dpy-18 sma-2 sma-3 unc-11 unc-13 unc-32 unc-36 unc-42 unc-64 unc-67 eT1 eDf2 Abstract: The Caenorhabditis elegans mutation e873, which results in a recessive uncoordinated phenotype (formerly named Unc-72) and which had been isolated after 32P treatment (Brenner 1974), has now been found to act as a crossover suppressor and to be associated with a translocation between linkage groups (LG's) III and V. The translocation has been named, eT1(III; V); eT1 acts as a dominant crossover suppressor for both the right half of LGIII and the left half of LGV, providing a balancer for a total of 39 map units. The uncoordinated e873 phenotype has been shown to be a consequence of an inactive unc-36III gene. It was possible to demonstrate that, in translocation heterozygotes, eT1 chromosomes marked with either sma-3 or dpy-11 segregate from normal LGIII, while those marked with bli-5, sma-2 or unc-42 segregate from normal LGV. Since bli-5 and sma-2 are normally on LGIII, and dpy-11 is normally on LGV, it is concluded that: (a) eT1 is a reciprocal translocation; (b) there is a breakpoint between sma-3 and sma-2 in LGIII (the region containing unc-36) and one between dpy-11 and unc-42 in LGV; (c) there is no dominant centromere between sma-2 and bli-5 on LGIII, since in eT1 these genes are not linked to a LGIII centromere. Similarly, it is highly unlikely that there is a centromere to the left of dpy-11 on LGV. The new gene order in eT1 was determined by measuring recombination rates between markers in eT1 homozygotes. It is concluded that the new order is: dpy-1 sma-3 (break) dpy-11 unc-60, and bli-5 sma-2 (break) unc-42 unc-51.--This is the first analysis of a C. elegans translocation with respect to reciprocity, breakpoints and new gene order. ------------------- Key: 555 Medline: Authors: Popham JD;Webster JM Title: Ultrastructural changes in C. elegans (Nematoda) caused by toxic levels of mercury and silver. Citation: Ecotoxicology & Environmental Safety 6: 183-189 1982 Type: ARTICLE Genes: Abstract: Mercury toxicity in Caenorhabditis elegans showed as lesions in esophageal muscles and intestinal cells and consisted of degradation of the cytoplasm and the formation of irregularly shaped cytosomes. Specimens intoxicated with silver showed changed cytosomes with a spongy matrix in the intestinal cells and ruffled membranes on the mitochondria of hypodermal cells. General ultrastructural responses reflecting a distress syndrome common to several heavy metals were also noted. The results are discussed with reference to the concept of using free-living nematodes to assist in the diagnosis of the causative toxic heavy metal in a complex. ------------------- Key: 556 Medline: Authors: DeCuyper C;Vanfleteren JR Title: Nutritional alteration of life span in the nematode C. elegans. Citation: Age 5: 42-45 1982 Type: ARTICLE Genes: Abstract: The longevity of the free-living nematode Caenorhabditis elegans was studied under two different nutritional regimes, one axenic and the other monoxenic. Axenic nematodes showed typical sigmoidal survival curves with exceptionally long tailing. Monoxenic worms died off much faster and the maximum life-span in bacterial culture was generally three to four times shorter than that obtained in axenic culture. When nematodes were transferred from axenic to monoxenic culture and vice versa at near adulthood the survival patterns observed were reminiscent of the final medium. These results are in agreement with the hypothesis that worms may die off prematurely in bacterial culture by toxins given off by the bacteria. ------------------- Key: 557 Medline: Authors: Shulkin DJ;Zuckerman BM Title: Spectrofluorometric analysis of the effect of centrophenoxine on lipofuscin accumulation in the nematode C. elegans. Citation: Age 5: 50-53 1982 Type: ARTICLE Genes: Abstract: A 41.3% mean decrease in lipofuscin was found in the nematode Caenorhabditis elegans following treatment of 6.8 mM centrophenoxine for 21 days. It is proposed that the spectrofluorometric technique is a convenient and more accurate method for determining cellular content of lipofuscin than planimetric and histochemical methodologies. This study further demonstrates the similarity of nematode lipofuscin to mammalian age pigment and provides a rapid, inexpensive method for evaluating the effects of pharmaceuticals on age-related lipofuscin ------------------- Key: 558 Medline: 82120290 Authors: Roberts TM;Ward S Title: Membrane flow during nematode spermiogenesis. Citation: Journal of Cell Biology 92: 113-120 1982 Type: ARTICLE Genes: fer-1 fer-15 Abstract: Two distinct types of surface membrane rearrangement occur during the differentiation of Caenorhabditis elegans spermatids into amoeboid spermatozoa. The first, detected by the behavior of latex beads attached to the surface, is a nondirected, intermittent movement of discrete portions of the membrane. This movement starts when spermatids are stimulated to differentiate and stops when a pseudopod is formed. The second type of movement is a directed, continual flow of membrane components from the tip of the pseudopod to its base. Both membrane glycoproteins and fluorescent phospholipids inserted in the membrane flow backward at the same rate, approximately 4 micrometers/min, although their lateral diffusion coefficients in the membrane differ by at least a factor of 5. These observations suggest that pseudopodial membrane movement is due to bulk flow of membrane components away from the tip ------------------- Key: 559 Medline: 82262402 Authors: Ward S;Klass M Title: The location of the major protein in C. elegans sperm and spermatocytes. Citation: Developmental Biology 92: 203-208 1982 Type: ARTICLE Genes: fer-1 fer-2 fer-3 fer-4 fer-6 Abstract: Using an affinity-purified antibody to the major sperm protein (MSP) in Caenorhabditis elegans sperm we have shown by immunofluorescence that the MSP is localized in the fibrous bodies of spermatocytes and early spermatids, in the cytoplasm of late spermatids, and in the pseudopods of spermatozoa. The MSP can also form crystalline inclusions in mutant and wild-type sperm. The function of this protein is still unknown, but its ability to form filaments and its localization in the pseudopod, together with the lack of actin in these sperm suggest that the MSP may be required for amoeboid motility. ------------------- Key: 560 Medline: 82260416 Authors: Chalfie M Title: Microtubule structure in C. elegans neurons. Citation: Cold Spring Harbor Symposia on Quantitative Biology 46: 255-261 1982 Type: REVIEW Genes: mec-7 unc-86 Abstract: Microtubules (MTs) are ubiquitous components of neuronal processes, and although they have been implicated in neurite outgrowth, shape maintenance, axonal transport, and sensory transduction, their function remains unclear. The MTs in the neurons of the nematode Caenorhabditis elegans have unusual structures that permit a comparative approach to the relationship of microtubule structure and function. A set of six touch-receptor neurons (the microtubule cells) contain prominent arrays of large MTs. These MTs have more protofilaments than do MTs in other neurons (15 as opposed to 11), and they respond differently to antimicrotubule drugs, fixation protocols, temperature, and mutation. Studies of C. elegans neurotubules suggest that most MT functions do not require long, continuous MTs or MTs with a specific number of protofilaments. Some functions, however, such as the sensory transduction of the microtubule cells, do require a specific microtubule substructure. A review of these data is presented in this ------------------- Key: 561 Medline: 83025078 Authors: Gossett LA;Hecht RM;Epstein HF Title: Muscle differentiation in normal and cleavage-arrested mutant embryos of C. elegans. Citation: Cell 30: 193-204 1982 Type: ARTICLE Genes: unc-54 zyg-1 Abstract: The differentiation of body-wall muscle cells was studied in the nematode Caenorhabditis elegans. Specific antibodies to myosin and paramyosin, major protein constituents of differentiated muscle, react with mesodermal cells in wild-type embryos towards the end of the first half of embryogenesis. Immunoreactive cells (2-16) first appear in embryos with 400-450 of the 550 cells present at hatching. Such embryos have developed at 25.5 degrees C for 4-4 1/2 hr beyond the two-cell stage. As development proceeds, a maximum of 81 immunoreactive cells forms four columns running anterior-posterior. Each column is composed of two lines of tightly opposed round cells, which then elongate into spindle-shaped cells. Mutant embryos in which cleavage arrests prematurely also generate cells that produce myosin and paramyosin. The initiation of muscle differentiation appears to be independent of the number of cell or nuclear divisions within a lineage or of the proliferation of other cells. These results suggest that the biosynthesis of muscle-specific proteins by nematode embryonic muscle cells is regulated by mechanisms intrinsic to these cells. ------------------- Key: 562 Medline: 83025093 Authors: Hedgecock EM;Thomson JN Title: A gene required for nuclear and mitochondrial attachment in the nematode C. elegans. Citation: Cell 30: 321-330 1982 Type: ARTICLE Genes: anc-1 Abstract: Nuclei occupy characteristic positions in most cells. In Caenorhabditis elegans, nuclei can be observed in living animals. Ordinary movements can distort the cells and displace their nuclei, but the extent of displacement is limited and nuclei return to their resting positions when the muscles relax. We have isolated five mutants in which the nuclei of certain epithelial cells are not elastically anchored but float freely within the cytoplasm. These mutations define a single gene, anc1, on linkage group 1. Mitochondrial positioning, observed by staining live animals with rhodamine 6G, is also disturbed in these cells. Additional defects, including abnormal tonofilaments and inappropriately positioned desmosomes, have been found by electron microscopy. The anc1 product may be a cytoskeletal component of nematode epithelial cells. Although the Anc1 phenotype is fully expressed in the newly hatched larvae, mutants develop and reproduce normally. Despite mispositioning of organelles, cuticle deposition and moulting are essentially normal. These mutations represent the null phenotype of the gene. At least three independent isolates revert spontaneously at high frequency (10(-5) to 10(-4) ). We suggest that anc1 is a member of a family of cytoskeletal genes. ------------------- Key: 563 Medline: 83012962 Authors: Kimble J;Hodgkin J;Smith T;Smith J Title: Suppression of an amber mutation by microinjection of suppressor tRNA in C. elegans. Citation: Nature 299: 456-458 1982 Type: ARTICLE Genes: sup-5 sup-7 tra-3 Abstract: Informational suppression by nonsense suppressor tRNAs has classically been a powerful tool for study of the mechanism of protein synthesis, to obtain conditional mutants and to demonstrate that a gene encodes a given protein product. In the nematode Caenorhabditis elegans, two genetically identified suppressors, sup-5 and sup-7, have recently been shown to be amber suppressor tRNAs. We report here the microinjection of sup-7 tRNA into the gonad of an animal bearing an amber allele of a maternal-effect mutant affecting sex determination (tra-3). We observe phenotypic suppression in the injected parent's offspring. tRNA from wild-type animals does not show this in vivo suppressor activity, and sup-7 tRNA does not cause suppression of a non-amber allele of the same gene. In vivo suppression of an amber mutant by microinjection provides a new means of gene manipulation in C. elegans. ------------------- Key: 564 Medline: 83080421 Authors: Greenwald IS;Horvitz HR Title: Dominant suppressors of a muscle mutant define an essential gene of C. elegans. Citation: Genetics 101: 211-225 1982 Type: ARTICLE Genes: lin-17 sup-5 sup-7 sup-9 sup-10 sup-11 unc-93 Abstract: The sup-11 1 locus of C. elegans was defined by rare dominant suppressors of unc-93(e1500) III, a mutation that affects muscle structure. All ten of these dominant suppressors have a recessive "scrawny" phenotype. Two additional classes of sup-11 alleles were identified. One class, null alleles, was obtained by reversion of the dominant suppressor activity. These null alleles are recessive embryonic lethals, indicating that sup-11 is an essential gene. Members of the second class, rare semidominant revertants of the "scrawny" phenotype, are partial suppressors of unc-93(e1500). The genetic properties of the dominant suppressor mutations suggest that they are rare missense mutations that confer a novel activity to the sup-11 protein. We consider some of the ways that sup-11 alleles might suppress unc-93(e1500), including the possibilities that the altered sup-11 proteins restore function to a protein complex or are modified products of a gene that is a member of an unc-93 ------------------- Key: 565 Medline: 83106425 Authors: Hartman PS;Herman RK Title: Radiation-sensitive mutants of C. elegans. Citation: Genetics 102: 159-178 1982 Type: ARTICLE Genes: flu-2 him-1 him-2 him-3 him-5 him-6 him-7 him-8 him-9 him-10 nuc-1 rad-1 rad-2 rad-3 rad-4 rad-5 rad-6 rad-7 rad-8 rad-9 rec-1 unc-58 Abstract: Nine rad (for abnormal radiation sensitivity) mutants hypersensitive to ultraviolet light were isolated in the small nematode Caenorhabditis elegans. The mutations are recessive to their wild- type alleles, map to four of the six linkage groups in C. elegans and define nine new games named rad-1 through rad-9. Two of the mutants-- rad-1 and rad-2--are very hypersensitive to X rays, and three--rad-2, rad-3 and rad-4--are hypersensitive to methyl methanesulfonate under particular conditions of exposure. The hypersensitivity of these mutants to more than one DNA-damaging agent suggests that they may be abnormal in DNA repair. One mutant--rad-5, a temperature-sensitive sterile mutant--shows an elevated frequency of spontaneous mutation at more than one locus; rad-4, which shows a cold-sensitive embryogenesis, reduces meiotic X-chromosome nondisjunction tenfold and partially suppresses some but not all mutations that increase meiotic X-chromosome nondisjunction; the viability of rad-6 hermaphrodites is half that of rad-6 males at 25 degrees; and newly mature (but not older) rad-8 hermaphrodites produce many inviable embryo progeny. Meiotic recombination frequencies were measured for seven rad mutants and found to be close to ------------------- Key: 566 Medline: 83028183 Authors: Klass M;Dow B;Herndon M Title: Cell-specific transcriptional regulation of the major sperm protein in C. elegans. Citation: Developmental Biology 93: 152-164 1982 Type: ARTICLE Genes: him-8 Abstract: The major protein found in nematode sperm exhibits a distinct pattern of developmental regulation. In the nematode Caenorhabditis elegans, the synthesis of the major sperm protein (15K) begins with the onset of spermatogenesis in both the male and hermaphrodite. Both spermatogenesis and 15K synthesis continue for the life of the male while in the protandrous hermaphrodite the major sperm protein is synthesized only during the fourth larval stage. Inhibitor studies using actinomycin D and a-actinin as well as Northern blot analysis have shown that the primary regulatory mechanism of this gene is at the transcriptional level. Recombinant molecules have been selected bearing the 15K genomic sequence by a positive hybridization translation assay. Using one of these cloned fragments as a probe for in situ hybridization, 15K transcripts have been localized to a specific region of the male gonad. These studies indicate that the gene for the major sperm protein is regulated by a cell-specific transcriptional control mechanism coincidental with the onset of sexual differentiation in the nematode. ------------------- Key: 567 Medline: 83028185 Authors: Sternberg PW;Horvitz HR Title: Postembryonic nongonadal cell lineages of the nematode Panagrellus redivivus: Description and comparison with those of C. elegans. Citation: Developmental Biology 93: 181-205 1982 Type: ARTICLE Genes: Abstract: The postembryonic nongonadal cell lineages of the nematode Panagrellus redivivus are described and compared with those of Caenorhabditis elegans. The newly hatched larvae of P. redivivus females and males and C. elegans hermaphrodites and males are very similar. An almost identical set of blast cells divides postembryonically in P. redivivus and C. elegans to produce similar changes in the neuronal, muscular, hypodermal, and digestive systems. Most of these cell lineages are invariant; however, there is substantial variablility in the number of cell divisions in the relatively extensive lineages of the lateral hypdermis of P. redivivus. Typically, in P. redivivus females, 55 blast cells generate 635 surviving progeny and 29 cell deaths; in P. redivivus males, 59 blast cells generate 758 surviving progeny and 35 cell deaths. The lineages generating the cells of the male tails of P. redivivus and C. elegans are almost identical; thus, the grossly different characteristics of these structures must reflect differences in the morphogenesis of cells equivalent in lineage history. Laser ablation experiments demonstrate that the gonad induces vulva development and that cell-cell interactions are important in specifying the fates of hypodermal precursor cells. The lateral hypodermal lineages provide striking examples of the apparent construction of complex lineages from modular sublineages; one simple pattern of cell divisions and cell fates occurs 70 times in the P. redivivus female. The differences in cell lineage between P. redivivus and C. elegans are relatively minor, and many appear to have involved two types of evolutionary change: the replacement of sublineages, and the modification of sublineages by the four classes of lineage transformations previously proposed based on a comparison of P. redivivus and C. elegans gonadal cell lineages. These types of differences suggest that the genetic programming of cell lineage includes instructions specifying where and when a particular sublineage is utilized, and other instructions specifying ------------------- Key: 568 Medline: Authors: Horvitz HR;Ellis HM;Sternberg PW Title: Programmed cell death in nematode development. Citation: Neuroscience Commentaries 1: 56-65 1982 Type: REVIEW Genes: ced-1 ced-2 ced-3 Abstract: The phenomenon of programmed cell death, which occurs during the normal development of many organisms and is particularly common in neural development, is intriquing. Why should organisms generate cells only to destroy them? We believe that studies of the cell deaths that occur in nematodes have provided some answers to this question. Programmed cell death is a prominent feature of nematode development. For example, the generation of the 816 nongonadal cells of the hermaphroditic free-living nematode Caenorhabditis elegans is accompanied by the generation and death of an additional 131 cells. Most of these deaths appear to involve cells that are neural in character. Neural cell death is similarly common during the development of C. elegans males and during the postembryonic development of both females and males of another nematode species, Panagrellus redivivus. Overall, for both sexes of these two nematode species, approximately 20% of all presumptive neural cells produced undergo ------------------- Key: 569 Medline: 83050944 Authors: Kramer JM;Cox GN;Hirsh D Title: Comparisons of the complete sequences of two collagen genes from C. elegans. Citation: Cell 30: 599-606 1982 Type: ARTICLE Genes: col-1 col-2 col-3 Abstract: Several collagen genes have been isolated from the nematode Caenorhabditis elegans. The complete nucleotide sequences of two of these genes, col-1 and col-2, have been determined. These collagen genes differ from vertebrate collagen genes in that they contain only one or two introns, their triplehelical regions are interrupted by nonhelical amino acid sequences and they are smaller. A high degree of nucleotide and amino acid homology exists between col-1 and col-2. In particular, the regions around cysteines and lysines are most highly conserved. The C. elegans genome contains 50 or more collagen genes, the majority of which probably encode cuticle collagens; col-1 and col-2 apparently are members of this large family of cuticle collagen genes. ------------------- Key: 570 Medline: 82272395 Authors: McLachlan AD;Karn J Title: Periodic charge distributions in the myosin rod amino acid sequence match cross-bridge spacings in muscle. Citation: Nature 299: 226-231 1982 Type: ARTICLE Genes: unc-54 Abstract: The amino acid sequence of the rod portion of nematode myosin, deduced from the sequence of the unc-54 heavy chain gene of Caenorhabditis elegans, is highly repetitive and has the characteristics of an a-helical coiled coil. The molecular surface contains alternate clusters of positive and negative charge. Interactions between charge clusters on adjacent molecules could account for the observed spacings of the myosin cross-bridges in muscle. Calculations also suggest that the N-terminal of the rod is only loosely associated with the thick filament backbone. Bending of the rod near the end of this region could allow the N-terminal section to act as a hinged arm during muscle contraction. ------------------- Key: 571 Medline: 83103105 Authors: Moerman DG;Plurad S;Waterston RH;Baillie DL Title: Mutations in the unc-54 myosin heavy chain gene of C. elegans that alter contractility but not muscle structure. Citation: Cell 29: 773-781 1982 Type: ARTICLE Genes: unc-22 unc-54 Abstract: Reversion analysis of mutants of unc-22 IV, a gene affecting muscle structure and function in Caenorhabditis elegans, led to the isolation of six extragenic dominant suppressors of the "twitching" phenotype of unc-22 mutants. All six suppressors are new alleles of unc-54 I, the major body wall myosin heavy chain gene. Homozygous suppressor strains are slow, stiff and have normal muscle structure, whereas previously identified unc-54 alleles confer flaccid paralysis and drastic reduction in thick filament number and organization. Placement of the three suppressor mutations s74, s77 and s95 on the genetic fine structure map of unc-54 demonstrates that they are clustered near the right end of the map. Since this end of the gene corresponds to the 5' end of the coding sequence, these suppressor mutations probably result in amino acid substitutions in the globular head of the myosin molecule, and should be of value in studies of myosin force ------------------- Key: 572 Medline: Authors: Horvitz HR Title: Factors that influence neural development in nematodes. Citation: "Repair and Regeneration in the Nervous System" Dahlem Workshop Report Series Proceedings, Berlin, 1981. Nicholls JG (ed), Springer-Verlag, NY. 24: 41-55 1982 Type: REVIEW Genes: lin-14 Abstract: Neurons in nematodes are generated by invariant cell lineages. The lineage history of a cell appears to limit its developmental potential, often to a unique fate. Some cells have multiple potential fates; the fate each expresses depends either upon interactions with other cells or upon specific genetically controlled temporal signals. If the principles of neural development in nematodes are similar to those in other organisms, specific conditions involving available cell types and positional and/or temporal cues must be satisfied for neural regeneration to ------------------- Key: 573 Medline: Authors: Epstein HF;Miller DM III;Gossett LA;Hecht RM Title: Immunological studies of myosin isoforms in nematode development. Citation: "Muscle Development: Molecular and Cellular Control." Pearson M and Epstein HF (eds), Cold Spring Harbor Laboratory. : 7-14 1982 Type: REVIEW Genes: Abstract: Much of this meeting is devoted to the study of multi-gene families and the differential expression of various members during muscle development. Structural analysis of myosin and then other muscle proteins by peptide mapping and amino acid sequencing first suggested that these isoforms are the products of different genes. The use of antibodies specific to distinct structural gene products has permitted detailed investigations of myosin structure, biosynthesis and degradation, and cellular location as muscle development proceeds. The small nematode, Caenorhabditis elegans, is a laboratory animal which offers genetic dissection and manipulation as tools in deciphering of gene regulation in terms of specific protein synthesis during muscle development. The examination of specific mutants by protein chemistry and immunochemistry has already proved a powerful comination in many fields. ------------------- Key: 574 Medline: 83105996 Authors: Hecht RM;Wall SM;Schomer DF;Oro JA;Bartel AH Title: DNA replication may be uncoupled from nuclear and cellular division in ts embryonic lethal mutants of C. elegans. Citation: Developmental Biology 94: 183-191 1982 Type: ARTICLE Genes: emb-7 emb-9 zyg-1 zyg-2 zyg-8 zyg-9 zyg-10 zyg-12 Abstract: The nuclear and DNA contents of 18 temperature-sensitive embryonic lethal mutants of Caenorhabditis elegans have been determined at the time of arrest. After each mutant was shifted to restrictive temperature, the embryonic arrest stage was recorded by the number of nuclei counted in embryonic squashes and as DNA nuclear equivalents recorded by flow cytometry. Together the two methods complemented each other and provided qualitative and quantitative information concerning the nuclear number, DNA content, morphological stage of arrest, and presence of anucleate embryonic cells. The arrest stage for most of the embryonic lethal mutants demonstrated their potential to continue nuclear division and DNA replication beyond their respective temperature-sensitive periods. These results suggested that the mutants' primary defect did not reside on a pathway closely coupled to DNA replication or nuclear division. For example, B65 contained up to 650 DNA nuclear equivalents beyond the end of its temperature-sensitive period at the 20- to 30-cell stage. B65 is of additional interest because it continued DNA synthesis beyond the normal 550-cell stage and at the same time failed to progress beyond the morphogenetic period. The presence of enlarged nuclei that contained extra DNA demonstrated that DNA replication was independent of nuclear and cellular division. For example, B1 and B244 arrested with 1 to 50 and 1 to 200 nuclei, respectively. However, they both contained 250 to 400 nuclear equivalents of DNA. Conversely, the presence of embryonic cells without nuclei suggested that cell division may also be independent of nuclear division or nuclear migration. The enlarged nuclear and anucleate embryonic cells were observed only in those mutants requiring a normal parental ------------------- Key: 575 Medline: Authors: Waterston RH;Moerman DG;Baillie DL;Lane TR Title: Mutations affecting myosin heavy chain accumulation and function in the nematode C. elegans. Citation: "Disorders of the Motor Unit." Schotland DM (ed), J. Wiley & Sons. : 747-760 1982 Type: REVIEW Genes: sup-3 unc-22 unc-54 Abstract: The small nematode Caenorhabditis elegans is the subject of intensive investigation into the genetic specification of muscle structure and function. Many mutations affecting muscle structure have been identified, and more than 20 genes have been defined by complementation and recombinational analysis. Biochemical and genetic studies have proved that one of these loci, unc-54 I, is the structural gene for a 210,000-dalton myosin heavy chain in the body-wall musculature. Specific mutations in this gene could help us to understand the role of the myosin heavy chain in the assembly and contraction of muscle. Additional myosin heavy chains, the products of other genes, are present in the body wall and pharyngeal musculature. Alterations in the tissue-specific expression of this family of genes might be useful in studying gene regulation. The classic genetic approaches of reversion and intracistronic recombinational analysis can be applied to these problems in C. elegans because of the ease of handling the large number of animals necessary for systematic application of these methods, and because of the strong phenotype associated with most unc-54 mutations. Reversion analysis can reveal intragenic suppressors of a variety of types and could be especially powerful in the study of the genetic specification of muscle where many gene interactions may be involved. We have, in other work, described allele-specific generalized suppressors in C. elegans that are likely to be informational suppressors. Riddle and Brenner reverted unc-54 mutants and uncovered a gene-specific suppressor, sup-3 V. Part of our current work has been directed toward understanding the molecular basis for sup-3 action on unc-54 mutants. We have also carried out reversion analysis on unc-22 mutants and, surprisingly, have found new alleles of unc-54 that suppress unc-22 expression. In addition, a genetic intracistronic map of the unc-54 gene has been constructed, and we have begun to position these new alleles on this ------------------- Key: 576 Medline: Authors: Fodor A;Deak P Title: Isolation and phenocritical period-analysis of conditional and non-conditional developmental mutants in C. elegans. Citation: Acta Biologica Academiae Scientiarum Hungaricae 32: 229-239 1982 Type: ARTICLE Genes: szT1 Abstract: Forty-five conditional, non-conditional and deletion mutants located on the X chromosome of the nematode Caenorhabditis elegans (C. elegans) were isolated by using a duplication (mnDp1) and a balancer chromosome (szT1). Phenocritical periods of three conditional and two non-conditional mutants were determined; their relation to the actual gene activities is discussed. ------------------- Key: 577 Medline: 83080440 Authors: Herman RK;Kari CK;Hartman PS Title: Dominant X-chromosome nondisjunction mutants of C. elegans. Citation: Genetics 102: 379-400 1982 Type: ARTICLE Genes: mnT2 mnT3 mnT6 mnT7 mnT8 mnT9 mnT10 mnT11 mnDp11 Abstract: Eight dominant X-chromosome nondisjunction mutants have been identified and characterized. Hermaphrodites (XX) heterozygous for any one of the mutations produce 20-35% male (XO) self-progeny compared with the wild-type frequency of 0.2%. Seven of the eight mutants carry X-autosome translocations. Three of these, represented by mnT2, involve linkage group (LG) II and show severe crossover suppression for X-linked markers. The two half-translocations comprising mnT2 are separable and of very unequal size. The smaller one includes the left tip of X and the right end of LGII and can exist as a free duplication, being present in addition to the normal chromosome complement, in either hermaphrodites or males; it has no effect on X nondisjunction. The reciprocal half-translocation of mnT2 includes the bulk of both LGII and X chromosomes; it disjoins regularly from a normal LGII and confers the property of X-chromosome nondisjunction. A fourth translocation, mnT10(V;X), is also reciprocal and consists of half-translocations that recombine with V and X, respectively. Either half-translocation of mnT10 can exist in heterozygous form in the absence of the other to give heterozygous duplication-deficiency animals; the property of X-chromosome nondisjunction is conferred, in homozygotes as well as heterozygotes, solely by one of the half-translocations, which is deficient for the left tip of the X. The final three translocations have X breakpoints near the right end of X and autosomal breakpoints near the right end of LGIV, the left end of LGV and the right end of LGI, respectively. All three are homozygous inviable. Males hemizygous for the X portion of any of the seven translocations are viable and fertile. The final mutant, mn164, maps as a point at or near the left tip of the X and causes X-chromosome nondisjunction in both heterozygotes and homozygotes. In heterozygotes, mn164 promotes equational nondisjunction of itself but not its wild-type allele. The mutants are discussed in light of the holocentric nature of the C. elegans chromosomes. It is proposed that the left end of the X chromosome plays a critical structural role in the segregation of X ------------------- Key: 578 Medline: 82220013 Authors: White JG;Horvitz HR;Sulston JE Title: Neurone differentiation in cell lineage mutants of C. elegans. Citation: Nature 297: 584-587 1982 Type: ARTICLE Genes: lin-5 unc-59 unc-85 Abstract: The nematode Caenorhabditis elegans develops by an essentially invariant sequence of cell divisions leading to an adult complement of 959 somatic cells. In this organism cell fate is correlated with cell lineage, suggesting that genealogy may be a determining factor for the differentiated state of a cell. The study of mutants with altered cell lineages may help elucidate the precise mechanisms by which cell fate is decided. Several cell lineage mutants have been isolated and characterized, some having more and some fewer cell divisions than wild type. We have now investigated the cell types produced by two cell lineage mutants; these mutants exhibit blocks in certain terminal or near terminal cell divisions, which in normal animals generally give rise to daughter cells that differentiate into distinctly different cell types. We find that the blocked cells in the mutants generally exhibit the differentiated characteristics of only one of the two daughter cells that normally would be produced. The differentiated state of the blocked precursors may be due to an intrinsic dominance of one cell type over another in what is essentially a fused cell, and/or it may reveal the state of commitment of the precursor in wild-type ------------------- Key: 579 Medline: 83010290 Authors: Waterston RH;Smith KC;Moerman DG Title: Genetic fine structure analysis of the myosin heavy chain gene unc-54 of C. elegans. Citation: Journal of Molecular Biology 158: 1-15 1982 Type: ARTICLE Genes: let-49 let-50 lev-11 sup-3 sup-5 sup-7 unc-54 Abstract: Taking advantage of the relative ease of detecting single wild-type animals among large numbers of Unc-54 mutant animals, rare intragenic recombinants were recovered between mutations of unc-54 I, the gene coding for the myosin heavy chain of Caenorhabditis elegans body wall musculature. Appropriate closely linked marker mutations were used to improve screening efficiency, to distinguish recombination and conversion events, and to establish the relative order of unc-54 mutations in the gene. From the analysis of more than 400 exceptional chromosomes recovered from tests involving 91 heteroallelic strains, 27 unc-54 mutations have been separated into ten distinct sites. Null mutations, comprising the majority of the mutations studied, are scattered throughout the map with the e1300 and st60 mutations located at the left and right ends, respectively. Three small deficiencies are clustered at an internal site nearer the left end. Two missense mutations lie to the right of these deficiencies. By correlating these results with molecular investigations of specific mutations, we conclude that the 5' end of the coding sequence is at the right end of the gene and is located distally on the chromosome. These correlations also demonstrate that the map includes at least 80% of the structural sequence. The genetic map allows us to infer the approximate location of mutations in the coding sequence, and should aid in the genetic dissection of ------------------- Key: 580 Medline: 82261911 Authors: Hosono R;Mitsui Y;Sato Y;Aizawa S;Miwa J Title: Life span of the wild and mutant nematode C. elegans. Effects of sex, sterilization and temperature. Citation: Experimental Gerontology 17: 163-172 1982 Type: ARTICLE Genes: emb-5 emb-9 Abstract: The survival of Caenorhabditis elegans was studied comparing animals of different sexes, sterilized animals, and animals grown at different temperatures as a prelude to more detailed cytological and genetic analysis of aged nematodes. Temperature-sensitive sterile mutants, animals sterilized by 5-fluorodeoxyuridine treatment, and wild-type males showed little difference in life span from that of wild-type hermaphrodites, although slight changes in P (time of beginning of the dying phase) or T1/2 (half-life of the population in the early dying phase) values were observed. At higher temperatures, P and T1/2 values markedly decreased, indicating a shortened life span. Temperature shift between 16 degrees C and 25 degrees C revealed that an increase in life span always involved low temperatures after the adult phase. High temperature treatment during the growing phase or after the adult phase caused an earlier start of the dying phase, but a downward temperature during the adult phase resulted in a great increase in the half-life of the population (T1/2). The results suggest that the life span of C. elegans is rigidly determined by somatic cells and markedly influenced by the effects of temperature on the cells during the post-mitotic ------------------- Key: 581 Medline: 82260464 Authors: Roberts TM;Ward S Title: Directed membrane flow on the pseudopods of C. elegans spermatozoa. Citation: Cold Spring Harbor Symposia on Quantitative Biology 46: 695-702 1982 Type: REVIEW Genes: fer-1 fer-2 him-5 Abstract: The capping of cross-linked surface receptors on lymphocytes and other cells and the centripetal movement of surface-attached particles on crawling cells are examples of directed surface membrane movement. One possible mechanism for moving membrane components is that cytoskeletal proteins recognize cross-linked surface receptors and drag them through the membrane bilayer to one pole of the cell. Favoring this theory are the localization of actin and/or myosin under capped or mobile cross-linked surface molecules and the biochemical coisolation of actin with capped proteins. Another possibility is that movement results from flow of bulk membrane or membrane lipid between an assembly point at one pole of the cell to a disassembly point elsewhere on the surface. Capping on sessile cells and rearward membrane movement on crawling cells have different functions. The clustering of surface receptors that occurs during capping seems to play a role in the transmission of signals from surface-bound ligands across the membrane. As pointed out by Abercrombie, membrane movement on crawling cells may participate in locomotion. Crawling requires continuous assembly of new cell-substrate contact sites at the leading edge of the cell. Rearward membrane movement would result from this polarized membrane assembly. Thus, it is reasonable that these two types of direct membrane movement could be driven by different mechanisms, with cytoskeletal linkage operating in sessile cells and membrane flow occurring on crawling cells. This notion is supported by studies showing two distinct mechanisms for capping, one occurring spontaneously on motile cells and the other requiring ligand cross-linkage on lymphocytes. Here we examine the surface membrane movements on the amoebid spermatozoon of the free-living nematode Caenorhabditis elegans. This cell exhibits a pronounced morphological asymmetry, with the cellular organelles segregated into a hemispherical cell body (3-4 um dia). The cell forms a single persistent pseudopod, filled with granular cytoplasm, that extends about 4 um. Three features make the C. elegans spermatozoon ideal for studying the crawling movements of metazoan cells. First, differentiation of sessile, spherical spermatids into spermatozoa can be activated in vitro with the monovalent ion ionophore monensin so that the onset of motility can be controlled. Second, the asymmetry of the cell is clearly defined with the cell-body-pseuodopod junction visible both externally and internally. Third, sperm-defective mutants can be isolated, allowing cellular motility to be analyzed genetically. We now report that surface membrane movement on C. elegans spermatozoa occurs exclusively on the pseudopod. This movement comprises centripetal bulk-membrane flow and is not restricted to rearrangement of cross-linked membrane components. Furthermore, surface ------------------- Key: 582 Medline: 82236182 Authors: Khan FR;McFadden BA Title: C. elegans: Decay of isocitrate lyase during larval development. Citation: Experimental Parasitology 54: 47-54 1982 Type: ARTICLE Genes: Abstract: Changes in the levels of isocitrate lyase, malate synthase, catalase, fumarase, and NADP+-isocitrate dehydrogenase have been investigated during larval development of the free-living nematode Caenorhabditis elegans in the presence and absence of Escherichia coli. The specific activities of isocitrate lyase, malate synthase, and catalase are maximal at the time of egg hatching and, thereafter, decline during larval development when larvae feed on E. coli, whereas in the absence of E. coli specific activities of the same enzymes increase for 12 hr and subsequently remain constant. There is, however, no change in specific activity of fumarase or NADP+-isocitrate dehydrogenase during the same developmental period, in either case. Cycloheximide at 100 uM arrests the decline of isocitrate lyase during development of feeding larvae but has no effect upon the appearance of isocitrate lyase during starvation. The latter is true also for 15 mM itaconate. There is inactivation of isocitrate lyase in crude extracts of frozen worms in comparison to that in analogous extracts prepared from freshly harvested nematodes. ------------------- Key: 583 Medline: 83030936 Authors: Miwa J;Tabuse Y;Furusawa M;Yamasaki H Title: Tumor promoters specifically and reversibly disturb development and behavior of C. elegans. Citation: Journal of Cancer Research & Clinical Oncology 104: 81-88 1982 Type: ARTICLE Genes: Abstract: The effect of phorbol ester tumor promoters on the development and behavior of a free-living soil nematode, Caenorhabditis elegans, was studied. When young developing C. elegans were grown on E. coli- seeded agar with low concentrations (0.1 microgram/ml) of 12-0- tetradecanoyl-phorbol-13-acetate or phorbol-12,13-didecanoate, their growth was arrested. These tumor promoters reduced the brood size when gravid adults were treated and caused uncoordinated movement in animals treated at any stage of development. The effects of these tumor promoters on nematode development and behavior were partially reversible. The nonpromoting derivatives phorbol and 4 alpha-phorbol- 12,13-didecanoate showed no effect on the animals. ------------------- Key: 584 Medline: 82236186 Authors: Huang S-P;Tattar TA;Rohde RA;Zuckerman BM Title: C. elegans: Effects of 5-hydroxytryptophan and dopamine on behavior and development. Citation: Experimental Parasitology 54: 72-79 1982 Type: ARTICLE Genes: Abstract: 5-Hydroxytryptophan (5-HTP) was introduced iontophoretically into the vulva region of Caenorhabditis elegans to examine behavioral responses to this putative neurotransmitter. Responses in esophageal basal bulb pulsation and/or vulval contractions occurred. Little relation was observed between dosage and behavioral response. Similar behavioral responses followed topical applications of 5-HTP. An inverse relationship between the rates of esophageal pumping and vulval contraction was recorded following both iontophoretic injection and topical application. Following iontophoretic application, young nematodes resumed body movement sooner than old nematodes did. Growth significantly increased when 5-HTP or dopamine was added to the culture medium, but neither chemical influenced fecundity or life span. ------------------- Key: 585 Medline: 83023040 Authors: Davis BO;Anderson GL;Dusenbery DB Title: Total luminescence spectroscopy of fluorescence changes during aging in C. elegans. Citation: Journal of Biochemistry 21: 4089-4095 1982 Type: ARTICLE Genes: Abstract: Total luminescence spectroscopy was employed to characterize and quantitate age-related changes in fluorescence in the nematode Caenorhabditis elegans, an established model for aging research. The excitation wavelength was varied between 250 and 590 nm in 10-nm increments. At each excitation wavelength, the emission wavelength was varied between 300 and 600 nm. Contour plots of corrected spectra were made. All fluorescence increased severalfold with age, except for that ascribed to tryptophan of soluble protein fractions. This general increase included fluorescence due to flavins, which is not expected to increase with age but has previously been observed to do so in this species. Blue emission peaks that approximated Schiff base product fluorescence were detected in whole aqueous homogenates, chloroform/methanol extracts, and detergent-cleaned cuticle preparations. Age-related increases in emission intensities of these peaks were demonstrated in aqueous homogenates and isolated cuticles. Cuticle preparations, known to be rich in collagenous protein, exhibited a fluorescence peak that approximated the recently described pyridinoline cross-link of vertebrate collagen. This peak, as well as the entire cuticle emission spectrum between 300 and 500 nm, increased dramatically with age. A fluorescence peak tentatively identified as cuticle tyrosine, characteristic of collagenous protein, also increased in older worms. The effectiveness of the spectroscopic technique in distinguishing individual fluorescence peaks in complex mixtures was demonstrated, and the potential of the ------------------- Key: 587 Medline: Authors: Shepherd AM Title: Interpretation of sperm development in nematodes. Citation: Nematologica 27: 122-125 1981 Type: REVIEW Genes: Abstract: With the increased use of the electron microscope to study nematode spermatogenesis and the cytology and physiology of sperm, interpretation of the processes and the terms applied to various stages have not been consistent. ------------------- Key: 588 Medline: 83065222 Authors: Johnson TE;Wood WB Title: Genetic analysis of life-span in C. elegans. Citation: Proceedings of the National Academy of Sciences USA 79: 6603-6607 1982 Type: ARTICLE Genes: Abstract: Crosses between Bristol and Bergerac strains of the self-fertilizing hermaphroditic nematode Caenorhabditis elegans do not show the heterosis effects for life-span that complicate analysis of interstrain crosses with Drosophila or mice. Instead they yield F1 progeny with life-spans similar to those of the parent strains. By analysis of life-span variation among progeny F2 populations from such crosses and by two independent analyses of life-spans among recombinant inbred lines derived from F2 individuals by 18 rounds of self-fertilization, we estimate that the heritability of life-span in C. elegans is between 20% and 50%. Recombinant inbred lines show a range in mean life-spans of 10 days to 31 days compared to life-spans of about 18 days for each of the two parental strains. We conclude that life-span variation in C. elegans has a substantial genetic component and that this organism offers promising opportunities for selective breeding of longer-lived strains and genetic ------------------- Key: 589 Medline: Authors: Ohba K;Ishibashi N Title: Effects of procaine on the development, longevity and fecundity of C. elegans. Citation: Nematologica 27: 275-284 1981 Type: ARTICLE Genes: Abstract: In medium containing 20 mg/ml of procaine-HCl, juvenile development of Caenorhabditis elegans almost ceased, and juveniles entered a dauer-like state. After transfer to procaine-free medium, the nematodes resumed growth and matured in about 4 days. After transfer to drug-free medium the fecundity of the treated nematodes was markedly reduced even by a one-day exposure to the drug, and unlike longevity the decline proceeded stepwise. Procaine-treated nematodes resisted desiccation less but resisted freezing as did juveniles in the dauer state from monoxenic cultures. Under the electron microscope procaine-treated juveniles had empty intestinal lumens but unlike dauer juveniles the morphology of this region had a thick cuticle ------------------- Key: 590 Medline: 83016664 Authors: Golden JW;;Riddle DL Title: A pheromone influences larval development in the nematode C. elegans. Citation: Science 218: 578-580 1982 Type: ARTICLE Genes: Abstract: A Caenorhabditis-specific pheromone and the food supply influence both entry into and exit from a developmentally arrested juvenile stage called the dauer larva. The pheromone increases the frequency of dauer larva formation and inhibits recovery but does not affect adult behavior such as chemotaxis and egg laying. The fatty acid-- like pheromone has been partially purified and characterized by a new bioassay. If similar developmental control mechanisms are used by parasitic nematodes, such mechanisms might be exploited to develop highly selective anthelmintic agents. ------------------- Key: 591 Medline: Authors: Abdulkader N;Gibert M-A;Starck J;Bosch C;Brun J Title: Temperature-sensitive mutations in C. elegans: A sterile mutation affecting oocyte I core relations. Citation: Revue de Nematologie 3: 201-212 1980 Type: ARTICLE Genes: Abstract: ------------------- Key: 592 Medline: 84059034 Authors: Rogalski TM;Moerman DG;Baillie DL Title: Essential genes and deficiencies in the unc-22 IV region of C. elegans. Citation: Genetics 102: 725-736 1982 Type: ARTICLE Genes: let-51 let-52 let-53 let-54 let-55 let-56 let-58 let-59 let-60 let-61 let-63 let-64 let-65 let-66 let-67 unc-22 unc-30 unc-31 unc-43 sDf2 sDf7 sDf8 sDf9 sDf10 Abstract: Five formaldehyde-induced deficiencies that uncover unc-22 IV, a gene affecting muscle structure in the nematode Caenorhabditis elegans were isolated and positioned. The largest deficiency, sDf2, extends in both directions from unc-22 and is approximately 1.0-2.0 map units in length. The other four deficiencies, sDf7, sDf8, sDf9 and sDf10, are all smaller than sDf2 and are located within the region uncovered by this deficiency. Thirty-seven ethyl methane-sulfonate-induced lethal and sterile mutations linked to unc-22 were isolated and tested for complementation with sDf2. Nineteen lethal mutations failed to complement sDf2. Sixteen of these were further positioned by recombination mapping and also by deficiency mapping with sDf7, sDf8, sDf9 and sDf10. These sixteen mutations define 11 new essential genes in this region. Eight of the genes lie in a 0.9-map unit interval to the left of unc-22, whereas the three remaining genes lie in a region of about 0.2 map units to the right of unc-22. We believe that two of the essential genes identified in this study, let-56 and let-52, are the adjacent genes on either side of unc-22. The lethal mutations exhibit a wide range of terminal phenotypes: from first stage larva to sterile ------------------- Key: 593 Medline: Authors: Rinker DL;Bloom JR Title: Phoresy between a mushroom-infesting fly and two free-living nematodes associated with mushroom culture. Citation: Journal of Nematology 14: 599-602 1982 Type: ARTICLE Genes: Abstract: Free-living nematodes are pests of commercial mushroom production. On occasions they contribute significantly to mushroom yield reductions; however, their role in decreased production is not fully understood. Control has been achieved through effective sanitation and good cultural practices. Pasteurization of the old crop has been practiced to kill nematodes in compost and structural framework. Proper preparation of compost, casing soil, and spawn effectively produces nematode-free materials, but despite these precautions, crops are often infested with nematodes. Hussey suggested that nematodes are transported into the houses by mushroom-infesting flies. Members of the Rhabditidae, Diplogasteridae, Chambersiellidae, Cephalobidae, Aphelenchidae, Aphelenchoididae, Cylindrocorporidae, Dorylaimidae, Neotylenchidae, Monochidae, Panagrolaimidae, Plectidae, Strongylidae, and Tylenchidae are reported to have phoretic associations with insects. Thus, the objective of this study was to determine if certain free-living nematode pests of commercial mushrooms could be transported by mushroom ------------------- Key: 594 Medline: Authors: Chitwood DJ;Lusby WR;Lozano R;Thompson MJ;Svoboda JA Title: Sterol metabolism in the nematode C. elegans. Citation: Lipids 19: 500-506 1984 Type: ARTICLE Genes: Abstract: The metabolism of various dietary sterols and the effects of an azasteroid on sitosterol metabolism in the free-living nematode Caenorhabditis elegans was investigated. The major unesterified sterols of C. elegans in media supplemented with sitosterol, cholesterol or desmosterol included 7-dehydrocholesterol (66.5%, 40.5%, 31.2%, respectively), cholesterol (6.7%, 52.3%, 26.9%), lathosterol (4.4%, 3.6%, 1.7%) and 4a-methylcholest-8(14)-en-3B-ol (4.2%, 2.1%, 3.8%). Esterified sterols, representing less than 20% of the total sterols, were somewhat similar except for a significantly higher relative content of 4a-methylcholest-8(14)-en-3B-ol (23.3%, 23.4%, 10.6%). Thus C. elegans not only removes the substituent at C24 of dietary sitosterol but possesses the unusual ability to produce significant quantities of 4a-methylsterols. When C. elegans was propagated in medium supplemented with sitosterol plus 5 ug/ml of 25-azacoprostane hydrochloride, the azasteroid stronly interfered with reproduction and motility of C. elegans and strongly inhibited the delta24-sterol reductase enzyme system; excluding sitosterol, the major free sterols of azacoprostane-treated C. elegans were cholesta-5,7,24-trien-3B-ol (47.9%), desmosterol (9.4%), fucosterol (2.1%) and cholesta-7,24-dien-3B-ol (2.0%). These 4 sterols are likely intermediates in the metabolism ------------------- Key: 596 Medline: 83138965 Authors: Nelson FK;Albert PS;Riddle DL Title: Fine structure of the C. elegans secretory-excretory Citation: Journal of Ultrastructure Research 82: 156-171 1983 Type: ARTICLE Genes: dpy-5 Abstract: The secretory-excretory system of C. elegans, reconstructed from serial-section electron micrographs of larvae, is composed of four cells, the nuclei of which are located on the ventral side of the pharynx and adjacent intestine. (1) The pore cell encloses the terminal one-third of the excretory duct which leads to an excretory pore at the ventral midline. (2) The duct cell surrounds the excretory duct with a lamellar membrane from the origin of the duct at the excretory sinus to the pore cell boundary. (3) A large H- shaped excretory cell extends bilateral canals anteriorly and posteriorly nearly the entire length of the worm. The excretory sinus within the cell body joins the lumena of the canals with the origin of the duct. (4) A binucleate, A-shaped gland cell extends bilateral processes anteriorly from cell bodies located just behind the pharynx. These processes are fused at the anterior tip of the cell, where the cell enters the circumpharyngeal nerve ring. The processes are also joined at the anterior edge of the excretory cell body, where the excretory cell and gland are joined to the duct cell at the origin of the duct. Secretory granules may be concentrated in the gland near this secretory-excretory junction. Although the gland cells of all growing developmental stages stain positively with paraldehyde-fuchsin, the gland of the dauer larva stage (a developmentally arrested third-stage larva) does not stain, nor do glands of starved worms of other stages. Dauer larvae uniquely lack secretory granules, and the gland cytoplasm is displaced by a labyrinth of large, transparent spaces. Exit from the dauer stage results in the return of active secretory morphology in fourth-stage larvae. ------------------- Key: 597 Medline: 83141017 Authors: Hartman PS;Herman RK Title: Somatic damage to the X chromosome of the nematode C. elegans induced by gamma radiation. Citation: Molecular & General Genetics 187: 116-119 1982 Type: ARTICLE Genes: her-1 tra-1 Abstract: Wild-type male embryos and young larvae of the nematode Caenorhabditis elegans were more sensitive than wild-type hermaphrodites to inactivation by gamma rays; wild-type males have one X chromosome per cell (XO), whereas wild-type hermaphrodites have two (XX). Furthermore, after transformation into fertile hermaphrodites by a her-1 mutation, XO animals were more radiosensitive than XX her-1 animals; and XX animals transformed into fertile males by a tra-1 mutation did not show increased radiosensitivity. It is concluded that wild-type males are more radiosensitive than wild-type hermaphrodites because they have one X chromosome rather than two, and the predominant mode of inactivation of XO animals involves damage to the single X chromosome. No sex- specific differences in survival were observed after UV irradiation. ------------------- Key: 598 Medline: 83027644 Authors: Himmelhoch S;Zuckerman BM Title: Xiphinema index and C. elegans: Preparation and molecular labeling of ultrathin frozen sections. Citation: Experimental Parasitology 54: 250-259 1982 Type: ARTICLE Genes: Abstract: A method for the orientation of nematodes for cryoultramicrotomy is described. Comparison of cryosections with sections prepared by conventional electron microscopic procedures showed satisfactory resolution of structural details in frozen sections. Labeling of frozen sections en face was achieved by cationized ferritin and colloidal iron. Actin was localized in cryosections of somatic muscle by immunoferritin labeling. The current study is a practical example of the application potential of cryoultramicrotomy to examination of nematode cytochemistry at a molecular ------------------- Key: 599 Medline: Authors: DeCuyper C;Vanfleteren JR Title: Oxygen consumption during development and aging of the nematode C. elegans. Citation: Comparative Biochemistry & Physiology 73A: 283-289 1982 Type: ARTICLE Genes: Abstract: 1. The oxygen consumption was measured in all four juvenile stages, the reproductive stage and the aged postreprodutive stage of the free-living nematode Caenorhabditis elegans, using the Cartesian diver method. 2. The uptake of oxygen as a function of body weight was VO2 = 1.66 W*0.70 for all stages except the aged stage and VO2 = 1.62 W*0.58 when both first stage juveniles and aged organisms were excluded (VO2 = nl O2/ug hr; W = wet weight). 3. The metabolic rate (VO2/W) was significantly lower in both first stage juveniles and aged adults. This is ascribed to utilization of fat stores by way of the glyoxylate cycle during embryogenesis and early morphogenesis and to a general failure of the metabolic machinery during senescence. 4. A comparison of the actual oxygen consumption with the amount of oxygen available to the nematodes by diffusion through the cuticle showed that the weight-specific coefficient b (0.70 or 0.58) could not be explained by decreasing ability to provide oxygen to body tissues with increasing worm size. 5. It is suggested that ATP dependent activities which occur at the cell surface might greatly determine the magnitude of the weight-specific coefficient in nematodes. ------------------- Key: 600 Medline: 83078557 Authors: Goldstein P Title: The synaptonemal complexes of C. elegans: Pachytene karyotype analysis of male and hermaphrodite wild-type and him mutants. Citation: Chromosoma 86: 577-593 1982 Type: ARTICLE Genes: him-8 Abstract: Only five synaptonemal complexes (SC), representing the 5 autosomes, are present in wild-type, him-4 and him-8, Caenorhabditis elegans males, whereas there are six SCs, accounting for 5 autosomal bivalents and the XX bivalent, in the C. elegans hermaphrodite. The univalent X chromosome of the male is present as a heterochromatic 'X- body' in spermatocyte pachytene nuclei. The XX bivalent in wild-type, him-4 and him-8 hermaphrodites (SC1, 2.5 microns in length) represented 6% of the total karyotype length and a SC of this size is missing from the respective male karyotypes. This corresponds with the fact that the total male karyotype length is only approximately 94% that of the hermaphrodite. Associated with the central element of the SC are structures termed 'SC knobs' that were first described in the wild-type hermaphrodite. The six SC knobs present in the wild- type hermaphrodite oocyte pachytene nuclei and the two SC knobs in the male spermatocyte pachytene nuclei are apparently randomly placed with the exception that they are never found at the ends of the SC. This is also true in him-4 and him-8 in which case there are 3 and zero SC knobs in the hermaphrodites, respectively, and one SC knob each in the male pachytene nuclei. The decrease in number of SC knobs in hermaphrodite to male represents a true sex difference. The presence or absence of the SC knobs may influence the X chromosome nondisjunction process and this effect is not localized to the region of the SC on which the SC knob is located. ------------------- Key: 601 Medline: 83114617 Authors: Rose AM;Baillie DL;Candido EPM;Beckenbach KA;Nelson D Title: The linkage mapping of cloned restriction fragment length differences in C. elegans. Citation: Molecular & General Genetics 188: 286-291 1982 Type: ARTICLE Genes: dpy-5 dpy-10 dpy-11 unc-22 unc-36 Abstract: The genomic DNA of two closely related strains of the nematode, Caenorhabditis elegans, Bristol (N2), and Bergerac (Bo), has different restriction endonuclease sites. Since these two strains interbreed, it is possible to regard the restriction length differences (RFLDs) as mutant variants. The N2 and Bo pattern can be segregated and mapped using classical genetic techniques. Utilizing a number of genetic markers existing in the N2 strain, we have constructed hybrid populations homozygous for either Bristol or Bergerac over a given chromosomal region with random Bristol-Bergerac composition for the remainder of the genome. Genomic restriction digests from these hybrid populations were probed with random cloned fragments of Bristol DNA. In this way, fragments were mapped to genetically well characterized regions of the C. elegans genome. 27 probes which hybridize to a total of 310 Kb of DNA were found to exhibit six restriction fragment differences. Four of these differences have been mapped, providing probes for four different genomic regions. We have combined classical genetics and recombinant DNA technology to construct linkage maps of cloned DNA fragments using restriction length differences. We are pursuing this approach in order to advance the knowledge of the genetic organization of C. elegans and to provide an experimental model for the study of many biological systems. It is hoped that this approach will also provide a practical solution to some difficult problems in nematode strain identification. Furthermore, the characterization of the families of transposable elements responsible for generating many of the RFLDs will undoubtedly contribute to the understanding of the biological significance of these ------------------- Key: 602 Medline: 83129414 Authors: Emmons SW;Yesner L;Ruan K-S;Katzenberg D Title: Evidence for a transposon in C. elegans. Citation: Cell 32: 55-65 1983 Type: ARTICLE Genes: Abstract: The C. elegans genome contains a 1.7 kb repeated DNA sequence (Tc1) that is present in different numbers in various strains. In strain Bristol and 10 other strains analyzed, there are 20 +/- 5 copies of Tc1, and these are located at a nearly constant set of sites in the DNA. In Bergerac, however, there are 200 +/- 50 interspersed copies of Tc1 that have arisen by insertion of Tc1 elements into new genomic sites. The interspersed copies of Tc1 have a conserved, nonpermuted structure. The structure of genomic Tc1 elements was analyzed by the cloning of a single Tc1 element from Bergerac and the comparison of its structure with homologous genomic sequences in Bristol and Bergerac. Tc1 elements at three sites analyzed in Bergerac undergo apparently precise excision from their points of insertion at high frequency. ------------------- Key: 603 Medline: 83078550 Authors: Albertson DG;Thomson JN Title: The kinetochores of C. elegans. Citation: Chromosoma 86: 409-428 1982 Type: ARTICLE Genes: mnDp2 Abstract: Light microscopy of the mitotic chromosomes of Caenorhabditis elegans suggests that non-localized kinetochores are present, since the chromosomes appear as stiff rods 1 to 2 micrometers in length and lack any visible constriction. The holokinetic structure was confirmed by reconstructions of electron micrographs of dividing nuclei in serially sectioned embryos. In prophase the kinetochore appears as an amorphous projection approximately 0.18-0.2 micrometer in diameter in cross section and in longitudinal section it appears to be continuous along the chromatin. At prometaphase and metaphase the kinetochore is a convex plaque covering the poleward face of the chromosome and extending the length of the chromosome. In longitudinal section the kinetochore is a trilaminar structure with electron dense inner and outer layers of 0.02 micrometer, and an electron lucent middle layer of 0.03 micrometer. The inner layer is adjacent to a more electron dense region of chromatin. The kinetochore was also seen as a band extending the length of the chromosome in whole mount preparations of chromosomes stained with ethanolic phosphotungstic acid. Most gamma ray induced chromosome fragments segregate normally in embryonic mitoses, but some fragments display aberrant behavior. Similar behavior was seen in embryos carrying a genetically characterized free duplication. It is suggested that mitotic segregation of small fragments may be inefficient because the probability of attachment of microtubules to the kinetochore is proportional to ------------------- Key: 604 Medline: 83090455 Authors: Kumazaki T;Hori H;Osawa S;Ishii N;Suzuki K Title: The nucleotide sequences of 5S rRNAs from a rotifer, Brachionus plicatilis, and two nematodes, Rhabditis tokai and C. elegans. Citation: Nucleic Acids Research 10: 7001-7004 1982 Type: ARTICLE Genes: Abstract: The nucleotide sequences of 5S rRNAs from a rotifer, Brachionus plicatilis, and two nematodes, Rhabditis tokai and Caenorhabditis elegans have been determined. The rotifer has two 5S rRNA species that are composed of 120 and 121 nucleotides, respectively. The sequences of these two 5S rRNAs are the same except that the latter has an additional base at its 3'-terminus. The 5S rRNAs from the two nematode species are both 119 nucleotides long. The sequence similarity percents are 79% (Brachionus/Rhabditis), 80% (Brachionus/Caenorhabditis), and 95% (Rhabditis/Caenorhabditis) among these three species. Brachionus revealed the highest similarity to Lingula (89%), but not to the nematodes (79%). ------------------- Key: 605 Medline: Authors: Hutzell PA;Krusberg LR Title: Fatty acid compositions of C. elegans and C. briggsae. Citation: Comparative Biochemistry & Physiology 73B: 517-520 1982 Type: ARTICLE Genes: Abstract: 1. Lipid accounted for 19.6 and 22.1% of the dry weight of Caenorhabditis elegans and C. briggsae, respectively. 2. The major portion of the fatty acids of both nematodes contained 18 or 20 carbon atoms. Seventy-eight per cent of the total fatty acid of C. elegans was unsaturated, as was 56% of that of C. briggsae. 3. The same 26 fatty acids occurred in both species; however, relative quantities of certain fatty acids varied. 4. The principal fatty acid fraction in both nematodes was 18:1. Vaccenic acid comprised 44.7 and 74.1% of the total 18:1 of C. briggsae and C. elegans, respectively. ------------------- Key: 606 Medline: 83103971 Authors: Vanfleteren JR Title: Nematode chromosomal proteins II. Fractionation and identification of the histones of C. elegans. Citation: Comparative Biochemistry & Physiology 73B: 709-718 1983 Type: ARTICLE Genes: Abstract: 1. Whole histone of the nematode Caenorhabditis elegans has been fractionated into the five main histone fractions by a combination of techniques including selective extraction, gel filtration, ion- exchange chromatography and electrophoresis. 2. The histones were identified on acid urea gels by a comparison of the electrophoretic profiles with those of calf thymus histone. 3. Acid urea gel electrophoresis of histone fraction H1 revealed one major and several minor bands. 4. At least three of these were most likely derived from H1 degradation, however. 5. Stepwise elution with 0.01 and 0.02 N HCl of the slightly lysine rich histones from carboxymethyl cellulose resolved two subfractions of H2B, designated H2B1 and H2B2 respectively. 6. Both H2B subtypes co-electrophoresed in acid urea gels containing 2.5 and 6.25 M urea. 7. The electrophoretic mobility of H2A was marginally higher at 2.5 M urea and identical with that of H2B1 and H2B2 at 6.25 M urea. 8. Molecular interaction considerably reduced the usefulness of molecular size fractionation of nematode histones. ------------------- Key: 607 Medline: Authors: Spence AM;Malone KMB;Novak MMA;Woods RA Title: The effects of mebendazole on the growth and development of C. elegans. Citation: Canadian Journal of Zoology 60: 2616-2623 1982 Type: ARTICLE Genes: Abstract: Mebendazole inhibits growth, reproductive capacity, and motility of Caenorhabditis elegans. Maximum reduction of length (50%) and volume (80%) was observed at 6.25 ug/mL mebendazole. At this concentration vulva formation was delayed by 18 h and egg production was reduced from 8 eggs/worm per hour to less than 1. The critical period for the effect of mebendazole on length was from 40 to 50 hours after hatching. The drug did not affect the viability of eggs, larvae, or adults. L1 and L2 larvae were motile in the presence of mebendazle (6.25 ug/mL); paralysis became apparent during the L3 and was completed in L4 and adult stages. Paralysed worms coiled into a ring and moved feebly and spasmodically. The first two moults occurred at the same time in control and treated worms, the L3/L4 and L4/adult moults were delayed by less than 1 h in the presence of the drug. Evidence is presented that these observed effects are caused by mebendazole and were not the consequence of partial starvation resulting from paralysis. ------------------- Key: 608 Medline: Authors: Hodgkin J Title: Male phenotypes and mating efficiency in C. elegans. Citation: Genetics 103: 43-64 1983 Type: ARTICLE Genes: ace-1 ace-2 act-1 act-2 act-3 bli-1 bli-2 bli-3 bli-4 bli-5 cat-1 cat-2 cat-4 cha-1 che-1 che-2 che-3 che-5 che-6 che-7 daf-3 daf-5 daf-6 daf-10 daf-12 daf-13 daf-16 daf-18 daf-20 dpy-1 dpy-2 dpy-3 dpy-4 dpy-5 dpy-6 dpy-7 dpy-8 dpy-9 dpy-13 dpy-14 dpy-17 dpy-18 dpy-19 dpy-20 dpy-21 dpy-22 dpy-23 dpy-25 dpy-26 flu-1 flu-2 flu-3 flu-4 him-1 him-2 him-3 him-5 him-6 him-7 him-8 him-9 lev-1 lev-11 lin-1 lin-2 lin-3 lin-4 lin-7 lin-10 lin-15 lin-18 lon-1 lon-2 mab-2 mab-3 mab-4 mab-5 mab-6 mab-7 mab-8 mab-9 mab-10 mec-1 mec-2 mec-3 mec-4 mec-5 mec-6 mec-7 mec-8 mec-9 mec-10 mec-12 mor-1 mor-2 nuc-1 osm-1 osm-3 osm-5 osm-6 rol-1 rol-3 rol-4 rol-6 sma-1 sma-2 sma-3 sma-4 smg-1 sqt-1 sqt-2 sqt-3 unc-1 unc-2 unc-3 unc-4 unc-5 unc-6 unc-7 unc-8 unc-9 unc-10 unc-11 unc-13 unc-14 unc-15 unc-16 unc-17 unc-18 unc-20 unc-22 unc-23 unc-24 unc-25 unc-26 unc-27 unc-29 unc-30 unc-31 unc-32 unc-33 unc-34 unc-35 unc-36 unc-37 unc-38 unc-39 unc-40 unc-41 unc-42 unc-43 unc-44 unc-45 unc-46 unc-47 unc-49 unc-50 unc-51 unc-52 unc-53 unc-54 unc-55 unc-57 unc-58 unc-59 unc-60 unc-61 unc-62 unc-63 unc-64 unc-65 unc-67 unc-68 unc-69 unc-70 unc-71 unc-73 unc-74 unc-75 unc-76 unc-77 unc-78 unc-79 unc-80 unc-81 unc-82 unc-83 unc-84 unc-85 unc-86 unc-87 unc-89 unc-93 unc-94 unc-95 unc-96 unc-97 unc-98 unc-100 unc-103 unc-104 vab-1 vab-2 vab-3 vab-6 vab-7 vab-8 vab-9 vab-10 Abstract: Mating behavior in adult male nematodes can be assayed by mating efficiency, i.e., the number of cross progeny sired by males under standard conditions. Mutant males from 220 strains, representing most known complementation groups of C. elegans, have been examined for mating efficiency and for anatomical abnormalities of the specialized male copulatory organs. These data extend the phenotypic description of these mutants and indicate what anatomical and behavioral components are necessary for the ability to mate successfully. Also, mutants with specific defects in the male were sought by establishing superficially wild-type hermaphrodite stocks after mutagenesis and testing the males segregated by these stocks for mating efficiency. Forty-nine of 1119 stocks yielded abnormal males. Seventeen were characterized in detail and found to be abnormal in sensory behavior (carrying mutations in the genes che-2 or che-3) or male genital anatomy (carrying mutations in one of the genes mab-1 to mab-10). Four of the mab (male abnormal) genes affect specific postembryonic ------------------- Key: 609 Medline: Authors: Hosono R;Hirahara K;Kuno S;Kurihara T Title: Mutants of C. elegans with Dumpy and Rounded head Citation: Journal of Experimental Zoology 224: 135-144 1982 Type: ARTICLE Genes: dpy-1 dpy-20 sma-1 Abstract: Mutations bearing morphological alterations in both head and body are reported in Caenorhabditis elegans. Although most dumpy mutants so far isolated have shorter bodies with normal head form, the mutants presented in this paper have rounded heads in addition to dumpy bodies. On examination with light- and scanning electron microscopes, defects in organs attached to the tip of head were not detected. The mutations were mapped as alleles of the dpy-20 gene on linkage group IV. Segregation of the head abnormality from dumpy body was not detected upon examination of over 10,000 descendants from heterozygous offspring (F1) produced by crossing mutant hermaphrodites with wild-type males. Revertants of dpy-20(cn142) allele were found to be almost wild-type in both head and other body morphology, supporting the possibility that both phenotypes in these alleles have been produced by a single mutation. Genetic analysis of two other revertants are also presented in this ------------------- Key: 610 Medline: 83143266 Authors: Tranquilla TA;Cortese R;Melton D;Smith JD Title: Sequences of four tRNA genes from C. elegans and the expression of C. elegans tRNA Leu (anticodon IAG) in Xenopus oocytes. Citation: Nucleic Acids Research 10: 7919-7934 1982 Type: ARTICLE Genes: Abstract: Four tRNA genes have been identified in cloned segments of Caenorhabditis elegans DNA by tRNA hybridisation and expression after injection into Xenopus laevis oocyte nuclei. From DNA sequencing these are (with DNA anticodon sequences) tRNAAsp (GTC), tRNALeu (AAG), tRNALys (CTT) and tRNAPro (TGG). Their flanking DNA sequences are compared. Two identical tRNALys (CTT) genes from different regions of the genome have quite unrelated 5' flanking sequences. The tRNA synthesised in Xenopus oocytes after injection of the tRNALeu cloned DNA has the modified anticodon IAG. The tRNALeu gene precursor transcript from injected oocytes has short 5' and 3' additional sequences and lacks certain of those modified bases found in the processed tRNA. ------------------- Key: 611 Medline: 83189113 Authors: Files JG;Carr S;Hirsh D Title: Actin gene famly of C. elegans. Citation: Journal of Molecular Biology 164: 355-375 1983 Type: ARTICLE Genes: act-1 act-2 act-3 Abstract: Four actin genes have been isolated from Caenorhabditis elegans that account for all of the major actin hybridization to total genomic DNA. Actin genes I, II and III are clustered within a 12 X 10(3) base region; gene IV is unlinked to the others. All four genes have been sequenced from at least nucleotide -109 to +250. Genes I and III are identical for the first 307 coding nucleotides. Genes I and II differ in 14 positions within the first 250 coding nucleotides; one difference substitutes an aspartic acid for a glutamic acid at codon 5. Genes I and IV differ in 18 positions within the first 259 coding nucleotides without causing any amino acid differences. Genes I, II and III have introns after the first nucleotide of codon 64 and gene IV has an intron between codons 19 and 20. The four nucleotide sequences thus far define two different amino acid sequences. Both of the amino acid sequences resemble vertebrate cytoplasmic actin more than vertebrate muscle actin. A DNA polymorphism between the Bristol and Bergerac strains has been used as a phenotypic marker in genetic crosses to map the cluster of actin genes within a 2% recombination interval on linkage group V between unc-23 and sma-1 in order to begin a molecular genetic analysis of the actin loci. ------------------- Key: 612 Medline: 83189127 Authors: McLachlan AD;Karn J Title: Periodic features in the amino acid sequence of nematode myosin rod. Citation: Journal of Molecular Biology 164: 605-626 1983 Type: ARTICLE Genes: unc-54 Abstract: Properties of the amino acid sequence of the nematode myosin rod region, deduced from cloned DNA, are analysed. The rod sequence of 1117 residues contains a regular region of 1094 residues, which has features typical of an alpha-helical coiled coil, followed by a short non-helical tailpiece at the carboxyl end. The hydrophobic amino acids show the expected seven-residue pattern a, b, c, d, e, f, g, which is modulated by a longer repeat of 28-residue zones. In addition, there are four one-residue insertions, or skip residues, at the ends of zones, at positions 351, 548, 745 and 970. Myosin is considerably less hydrophobic than tropomyosin or alpha-keratin and the outer surface of the coiled coil is covered by clusters of positive and negatively charged amino acid side-chains. Molecular models suggest that the coiled coil is continuous throughout the rod, with an approximately uniform left-handed twist, except for a few turns of helix near each skip region, where the twist flattens out to accommodate the extra residue. Fourier transforms of the amino acid profiles show strong periodicities based on repeats of seven residues (7/2 and 7/3) and 28 residues (especially 28/3 and 28/9). The positive and negative charges each have strong 28/3-residue periodicities that are out of phase with one another. The negative charges also show a 196/9-residue modulation frequency, which may reflect the presence of a 196-residue structural unit in muscle, approximately 2 X 143 A long. The distribution of charged amino acids suggests that electrostatic forces are dominant in forming the thick filament structure. Models that allow regular patterns of interacting charges are restricted and the simplest types are discussed. ------------------- Key: 613 Medline: Authors: Waterston RH;Bolten S;Sive HL;Moerman DG Title: Mutationally altered myosins in C. elegans. Citation: "Muscle Development: Molecular and Cellular Control." Pearson M and Epstein HF (eds), Cold Spring Harbor Laboratory. : 119-127 1982 Type: REVIEW Genes: sup-5 sup-7 unc-54 Abstract: In studies of myogenesis and muscle contraction in Caenorhabditis elegans, more than 20 genes have been found that affect muscle structure. Of these, one gene, unc-54 I, has proved to be especially well suited for a detailed molecular genetic analysis. The unc-54 gene codes for the major myosin heavy chain of the body-wall musculature, with one or more unidentified genes coding for a minor body-wall myosin as well as pharyngeal and other myosins. More than 100 independently isolated mutations have been found for the unc-54 gene, and these have served as the basis for an increasingly sophisticated analysis of the gene and its products. Whereas others have focused on the cloning and sequencing of the gene or the effects of mutants on thick filament formation, our efforts have concentrated on a thorough genetic analysis of the gene. These studies include the isolation of new alleles of unc-54, the construction of a fine-structure map of the gene, and the interpretation of this genetic map in physical terms. ------------------- Key: 614 Medline: 83132844 Authors: Sharrock WJ Title: Yolk proteins of C. elegans. Citation: Developmental Biology 96: 182-188 1983 Type: ARTICLE Genes: Abstract: A group of proteins judged on several criteria to be yolk proteins have been isolated from a homogenate of the nematode Caenorhabditis elegans. Comparison of partial proteolysis fragments indicates that the two bands of a 170,000-dalton doublet (yp170) are closely related; bands observed at 115,000 daltons (yp115) and 88,000 daltons (yp88) appear to be structurally distinct. All three yolk protein species are glycoproteins, as judged by binding of the lectin concanavalin A. The yp170 doublet has been purified by gel filtration in the presence of sodium dodecyl sulfate. An antiserum obtained by immunization with the purified yp170 doublet does not bind either of the two smaller proteins. Staining of C. elegans eggs by indirect immunofluorescence with the anti-yp170 serum indicates a dispersed cytoplasmic location for the antigen throughout embryogenesis, with apparent segregation to the intestine immediately prior to hatching. ------------------- Key: 615 Medline: 83132845 Authors: Kimble J;Sharrock WJ Title: Tissue-specific synthesis of yolk proteins in C. elegans. Citation: Developmental Biology 96: 189-196 1983 Type: ARTICLE Genes: fem-1 fem-2 him-1 him-8 tra-1 tra-2 Abstract: The primary site of yolk protein synthesis in the nematode, Caenorhabditis elegans, has been determined. In animals containing no gonadal cells (obtained by laser ablation of the gonadal precursor cells early in development), yolk proteins are present in abundance. This demonstrates that yolk proteins are made outside the gonad. An examination of proteins present in tissues isolated by dissection, and a comparison of proteins synthesized by isolated tissues incubated in vitro have identified the intestine as the major site of yolk protein synthesis. We propose that yolk proteins are synthesized in the intestine, secreted from the intestine into the body cavity, and taken up from the body cavity by the gonad to reach oocytes. The site of yolk protein synthesis has also been examined in four mutants that have largely male somatic tissues, but a hermaphrodite germ line. Here again, yolk proteins are produced by intestines in a hermaphrodite-specific manner. This suggests that sex determination is coordinately regulated in intestinal and germ line tissues. ------------------- Key: 616 Medline: Authors: Schierenberg E Title: Development of the nematode C. elegans. Citation: "Developmental Biology of Freshwater Invertebrates." Harrison FW and Cowden RR (eds), Alan R. Liss, NY. : 249-281 1982 Type: REVIEW Genes: Abstract: Caenorhabditis elegans is a free-living, nonparasitic nematode. It is a self-fertilizing hermaphrodite. Males arise spontaneously by nondisjunction of X-chromosomes. Of all eukaryotic organisms C. elegans has probably been most extensively studied at the cellular level. Within 12 hours the fertilized egg develops into a young larva with 558 nuclei (560 in the male). During postembryonic development the animal proceeds through four larval stages increasing its number of nuclei to 959 (1,031 in the male) plus some 2,000 germ cells (about 1,000 in the male). The cell lineages from fertilization to adulthood have been completely analyzed in living embryos and animals. This and its well-established genetics (more than 300 genes have been mapped on the six linkage groups) make it a suitable model organism to study problems of gene action and development. Various techniques have been used to interfere with normal development (including laser-induced cell ablations) and to analyze development on the subcellular level (including recombinant DNA technology). The characteristic features of rigidly determined development, the low cell number, and the knowledge of cellular events should make it possible to identify molecular action in situ and relate it to the structure and ------------------- Key: 618 Medline: Authors: Wood WB;Strome S;Laufer JS Title: Localization and determination in embryos of C. elegans. Citation: "Time, Space, and Pattern in Embryonic Development." Jeffery WR and Raff RA (eds), Alan R. Liss, NY. : 221-239 1983 Type: REVIEW Genes: Abstract: More than 100 years ago, early European embryologists had posed the two central questions of animal development: First, how is the sameness of cells and organisms maintained during development and reproduction, and what factors transmit this hereditary information? Second, how do the cells of an embryo become different; what factors dictate that a particular cell at a particular time and position becomes committed to a particular developmental pathway? In the intervening century, we have largely answered the first question, acquiring extensive information about the genetic machinery and how it works. By contrast, we have gained little new understanding of the epigenetic process responsible for temporal and positional control of cell determination in embryos. How this process operates remains a central problem of contemporary ------------------- Key: 619 Medline: Authors: Rosenbluth RE;Cuddeford C;Baillie DL Title: Mutagenesis in Caenorhabditis elegans. I. A rapid eukaryotic mutagen test system using the reciprocal translocation eT1(III;V). Citation: Mutation Research 110: 39-48 1983 Type: ARTICLE Genes: eT1 Abstract: The advantages of developing mutagenicity tests using the nematode, Caenorhabditis elegans, are discussed and an efficient in vivo test for detecting heritable autosomal recessive lethals over 40 map units is described. The test uses the reciprocal translocation, eT1(III;V), as a balancer. Dose-response curves for EMS (0.004-0.06 M) and gamma-radiation (500-3000 R) were obtained. The spontaneous induction frequency for lethal mutations in 40 map units was found to be 0.06%. Mutations could be detected within 10 days and confirmed within another 5 days. From the point of view of C. elegans genetics, the EMS and gamma-ray curves demonstrate that eT1 can be used to test the efficacy of a particular mutagen in this organism. Although the present eT1 protocol simultaneously screens hermaphrodite oocyte and sperm chromosomes, variations of the protocol that screen oocyte and sperm ------------------- Key: 620 Medline: 85040332 Authors: Ambros V;Horvitz HR Title: Heterochronic mutants of the nematode C. elegans. Citation: Science 226: 409-416 1984 Type: ARTICLE Genes: lin-4 lin-14 lin-28 lin-29 Abstract: Mutations in the Caenorhabditis elegans genes lin-14, lin-28, and lin- 29 cause heterochronic developmental defects: the timing of specific developmental events in several tissues is altered relative to the timing of events in other tissues. These defects result from temporal transformations in the fates of specific cells, that is, certain cells express fates normally expressed by cells generated at other developmental stages. The identification and characterization of genes that can be mutated to cause heterochrony support the proposal that heterochrony is a mechanism for phylogenetic change and suggest cellular and genetic bases for heterochronic variation. ------------------- Key: 621 Medline: Authors: Schierenberg E;Cassada R Title: Cell division patterns and cell diversification in the nematode C. elegans. Citation: "Stem Cells, Their Identification and Characterization." Potten CS (ed), Churchill Livingstone. : 73-92 1983 Type: REVIEW Genes: Abstract: ------------------- Key: 622 Medline: 83111132 Authors: Culotti JG;Klein WL Title: Occurrence of muscarinic acetylcholine receptors in wild-type and cholingergic mutants of C. elegans. Citation: Journal of Neuroscience 3: 359-368 1983 Type: ARTICLE Genes: ace-1 ace-2 lev-1 lev-8 lev-9 lev-10 lev-11 unc-13 unc-22 unc-29 unc-38 unc-50 unc-63 unc-68 unc-74 Abstract: Crude homogenates of the nematode worm Caenorhabditis elegans were shown to bind the cholinergic antagonists [3H]N-methylscopolamine and quinuclidinyl benzilate ([3H]QBN) with high affinity. The dissociation constant for [3H]N-methylscopolamine binding determined from equilibrium saturation experiments (KD=3.7 X10*-10 M) was in good agreement with that determined from forward and reverse rate constants (KD=koff/kon=5X10*-10M). These binding sites were blocked sterospecifically by the (+) enantiomer of the muscarinic antagonist benzetimide, as would be expected of true muscarinic receptors. Furthermore, competition experiments with unlabeled cholinergic agonists and antagonists indicate that [3H]QNB and [3H]N-methylscopolamine bind to the same sites in nematode homogenates and that these sites are similar but not identical to muscarinic receptors in vertebrates. The concentration of [3H]N-methylscopolamine and [3H]QNB binding sites in adult populations of wild-type nematodes was approximately 10 fmol/mg of protein. This was approximately 4-fold lower than the concentration of binding sites in young (L1 and L2 stage) juveniles. These stage-specific differences in binding site concentrations parallel differences in acetylcholinesterase activity in larval and adult nematodes. Three methods of elevating cholinergic agonist levels in vivo were attempted in order to determine whether regulation of muscarinic receptors occurs in nematodes as it does in vertebrates. Two methods involved prolonged in vivo inhibition of acetylcholinesterase activlty, while the third method involved in vivo treatment with the potent agonist levamisole. All three methods failed to reveal down regulation of muscarinic receptors, suggesting that this regulatory mechanism may not exist in nematodes. Finally, phenotypic revertants of acetylcholinesterase-deficient double mutants as well as a class of agonist-resistant mutants were screened for possible alterations in [3H]QNB or [3H]N-methylscopolamine binding levels. None of these mutants exhibited gross deficiencies in [3H]QNB or [3H]N-methylscopolamine binding, although partial deficiencies might have gone undetected by the methods used here. Our binding studies show that muscarinic receptors, which mediate a large proportion of cholingeric signaling in advanced vertebrates, are also present in the very ------------------- Key: 623 Medline: Authors: Zuckerman BM;Geist MA Title: Effects of vitamin E on the nematode C. elegans. Citation: Age 6: 1-4 1983 Type: ARTICLE Genes: Abstract: Vitamin E at 200 ug/ml significantly extended the mean lifespan and extended maximum lifespan of the nematode Caenorhabditis elegans when supplied early in the prereproductive stage. At this concentration, vitamin E increased growth, but did not affect fecundity or the length of the reproductive period. The vitamin E effect was not passed from the parents to the progeny. Evaluations of the effects of vitamin E on lipofuscin accumulation were inconclusive. The results are compared to previous studies on C. briggsae and Turbatrix aceti. ------------------- Key: 624 Medline: 83267327 Authors: Wolf N;Priess J;Hirsh D Title: Segregation of germline granules in early embryos of C. elegans: An electron microscopic analysis. Citation: Journal of Embryology & Experimental Morphology 73: 297-306 1983 Type: ARTICLE Genes: Abstract: Using an improved fixation method for electron microscopy, we have found germline granules in Caenorhabditis elegans embryos shortly after fertilization and prior to the first cleavage. They are localized in the egg cytoplasm which becomes segregated into the posterior blastomere at the first cleavage. In the following divisions, the granules continue this pattern of asymmetric segregation and are ultimately segregated into the germline precursor cell. The granules are then symmetrically segregated into the germline cells. ------------------- Key: 625 Medline: 83157610 Authors: Gabius HG;Graupner G;Cramer F Title: Activity patterns of amino acyl-tRNA synthetases, tRNA methylases, arginyltransferase and tubulin-tyrosine ligase. Citation: European Journal of Biochemistry 131: 231-234 1983 Type: ARTICLE Genes: Abstract: As a step in the characterization of development and ageing in the nematode Caenorhabditis elegans, the activities of different groups of enzymes that supposedly exert modulating functions in and after protein synthesis have been determined. From embryonic (E), the four juvenile larval stages (L1-L4) and the gravid adult (A,A+), the selection of defined developmental stages extends to two different preparations of aged nematodes (S10, S12). Some aminoacyl-tRNA synthetase activities remain nearly unchanged in all stages up to the adult, some increase continuously during the larval stages and the remaining activities show stage-specific alterations. Upon ageing all activities except the one for tryptophan decrease sharply, tRNA methylase activities increase from E to L4, decrease from L4 to adult and to aged nematodes with only qualitative alterations in substrate specificity. The activity of tubulin: tyrosine ligase exhibits a parallel pattern, while arginyltransferase activity has a plateau between L2 and L4. The results are consistent with the idea of a modulation of protein synthesis and other cellular processes by quantitative activity changes during ------------------- Key: 626 Medline: Authors: Bazzicalupo P Title: C. elegans - A model system for the study of nematodes. Citation: "Molecular Biology of Parasites." Guardiola J, Luzzato L and Trager W (eds), Raven Press, NY. : 73-92 1983 Type: REVIEW Genes: ace-1 ace-2 flu-1 flu-2 flu-3 flu-4 unc-15 unc-54 Abstract: Nematodes are a very large group of animals. The estimated 500,000 species represent an independent phylum, and a very successful one, since they are found, with the exception of the pelagic and aerial habitats, in every type of environment. The great majority of nematodes are free-living and inhabit in large numbers the top few centimeters of the ocean's bed, fresh water muds, and a variety of soils. In the soil, where it has been measured, their biomass is comparable to that of insects. A few hundred species are extremely important in human health and agriculture because of their parasitic relationship to plants and animals. In humans, parasitic nematodes can cause very severe diseases, such as filariasis and river blindness (Oncocercus)... ------------------- Key: 627 Medline: 83223565 Authors: Hedgecock EM;Sulston JE;Thomson JN Title: Mutations affecting programmed cell deaths in the nematode C. elegans. Citation: Science 220: 1277-1279 1983 Type: ARTICLE Genes: ced-1 ced-2 ced-3 mec-4 nuc-1 Abstract: Mutations in two nonessential genes specifically block the phagocytosis of cells programmed to die during development. With few exceptions, these cells still die, suggesting that, in nematodes, engulfment is not necessary for most programmed deaths. Instead, these deaths appear to occur by cell suicide. ------------------- Key: 628 Medline: 83220736 Authors: Russnak RH;Jones D;Candido EPM Title: Cloning and analysis of cDNA sequences coding for two 16 kilodalton heat shock proteins (hsps) in C. elegans: homology with the small hsps of Drosophila. Citation: Nucleic Acids Research 11: 3187-3205 1983 Type: ARTICLE Genes: Abstract: The nucleotide sequences of two different cDNAs, CEHS48 and CEHS41, coding for the 16,000 dalton heat shock proteins (hsps) of Caenorhabditis elegans have been determined. CEHS48 codes for a polypeptide of 135 amino acids, approximately 15 fewer than the complete protein while CEHS41 is missing approximately 46 amino acids. From nucleotide 113 to the TAA termination signal the extent of homology between the sequences is 91%. Toward the 5' ends, the homology drops to 20% and results in completely divergent amino acid sequences. The 3' noncoding regions are only 30% homologous. Only CEHS48 contains a poly(A) signal and a poly(A) tail, suggesting that CEHS41 has an incomplete 3' end. The region from amino acid 43 to amino acid 115 shows extensive homology with corresponding regions in the four small hsps of Drosophila melanogaster and in mammalian alpha- crystallin. Two-dimensional gel analysis of in vitro synthesized hsp16 reveals the existence of five distinct components of identical molecular weights, but with different isoelectric points. ------------------- Key: 629 Medline: 83223597 Authors: Chalfie M;Thomson JN;Sulston JE Title: Induction of neuronal branching in C. elegans. Citation: Science 221: 61-63 1983 Type: ARTICLE Genes: mab-5 Abstract: The two postembryonic touch receptor neurons in the nematode Caenorhabditis elegans arise from essentially identical cell lineages and have the same ultrastructural features. The cells are found in different positions in the animal, however, and differ in neuronal branching, connectivity, and function. These structural and functional differences are not seen when cells are placed in similar positions by mutation or laser-induced damage. Thus, some, but probably not all, of the differentiated properties of these cells are a consequence of their cellular ------------------- Key: 630 Medline: 83245049 Authors: Hodgkin J Title: Two types of sex determination in a nematode. Citation: Nature 304: 267-268 1983 Type: ARTICLE Genes: fem-1 her-1 sup-7 tra-1 tra-2 tra-3 eDf2 Abstract: Sex in the nematode Caenorhabditis elegans is normally determined by a genic balance mechanism, the ratio of X chromosomes to autosomes, so that XX animals are self-fertilizing hermaphrodites and X0 animals are males. However, recessive mutations of the autosomal gene tra-1 III cause both XX and X0 animals to develop into males, and a linked dominant mutation causes both XX and X0 animals to develop into females. Here I show that these two kinds of mutation are allelic, and that stable mutant strains can be constructed in which sex is determined not by X-chromosome dosage but by the presence or absence of a single active gene. In these strains the autosomes carrying the tra-1 locus are in effect homomorphic Z and W sex chromosomes, and the sexes are homogametic ZZ males and heterogametic ZW females, in contrast to the wild-type arrangement of homogametic XX hermaphrodites and heterogametic X0 males. ------------------- Key: 631 Medline: 83221640 Authors: Liao LW;Rosenzweig B;Hirsh D Title: Analysis of a transposable element in C. elegans. Citation: Proceedings of the National Academy of Sciences USA 80: 3585-3589 1983 Type: ARTICLE Genes: Abstract: A transposable element, designated Tc1, has been characterized in Caenorhabditis elegans. Tc1 is 1.7 kilobases long, has an inverted terminal repeat of less than 100 base pairs, and is repeated as a highly conserved element. The copy number and genomic positions of Tc1 are extremely variable among strains, implying that Tc1 is mobile. However, progeny of interstrain crosses did not show hybrid dysgenic traits that might be due to Tc1 transposition. ------------------- Key: 632 Medline: 83233129 Authors: Tabuse Y;Miwa J Title: A gene involved in action of tumor promoters is identified and mapped in C. elegans. Citation: Carcinogenesis 4: 783-786 1983 Type: ARTICLE Genes: dpy-9 tpa-1 Abstract: We isolated mutants of the nematode Caenorhabditis elegans resistant to 12-O-tetradecanoylphorbol-13-acetate (TPA). The TPA-resistant mutants, although they grew somewhat smaller than normal, reproduced well and behaved normally in TPA; they also did similarly in another phorbol ester tumor promoter, phorbol-12,13-didecanoate (PDD), thus proving they are also resistant to PDD. All the mutations defined by these TPA-resistant mutants were semidominant to the wild-type allele. The 15 independently isolated mutants all fell into the same complementation group, defining a single gene, tpa-1. The gene tpa-1 mapped near the marker gene dpy-9 on chromosome IV. ------------------- Key: 633 Medline: 83210585 Authors: Edwards MK;Wood WB Title: Location of specific messenger RNAs in C. elegans by cytological hybridization. Citation: Developmental Biology 97: 375-390 1983 Type: ARTICLE Genes: Abstract: We have developed an autoradiographic technique for detecting specific Caenorhabditis elegans messenger RNA molecules in situ by hybridization of labeled, cloned DNA probes to fixed tissue sections and squashes of embryos and adults. We report analyses with probes of actin and collagen gene sequences from a C. elegans genomic clone library. Hybridization is RNase sensitive and tissue specific. In adults the actin probe, which recognizes cytoplasmic as well as muscle actin mRNA, hybridizes strongly to muscle and distal gonad (ovary), somewhat less strongly to maturing oocytes, and weakly to intestine. The collagen probe hybridizes weakly to distal gonad and intestine and very strongly to subcuticular tissues, in particular to the hypodermal cells and syncytial cytoplasm of the lateral hypodermal ridges, which are the sites of cuticle synthesis. In embryos, hybridization to squashes indicates that actin message is present at fertilization, decreases during early cleavage, and then increases again during morphogenesis. By contrast, collagen message is absent until the 100-cell stage and then increases rapidly during morphogenesis. The number of cells labeled is consistent with the view that the collagen probe hybridizes to hypodermal precursor cells. We estimate that our present methods can detect messages representing about 0.2% or more of the total mRNA population, and increases in this sensitivity should be possible. Therefore, the cytological hybridization technique should be useful for determining temporal and spatial patterns of specific mRNA distributions during development, at least for abundant and ------------------- Key: 634 Medline: 83235332 Authors: Ward S;Hogan E;Nelson GA Title: The initiation of spermiogenesis in the nematode C. Citation: Developmental Biology 98: 70-79 1983 Type: ARTICLE Genes: fem-1 him-5 Abstract: Spermiogenesis in nematodes involves the activation of sessile spherical spermatids to motile bipolar amoeboid spermatozoa. In Caenorhabditis elegans males spermiogenesis is normally induced by copulation. Spermatids transferred to hermaphrodites as well as some of those left behind in the male become spermatozoa a few minutes after mating. Spermiogenesis can also be induced in vitro by the ionophore monensin (G.A. Nelson and S. Ward, 1980, Cell 19, 457-464) and by weak bases such as triethanolamine. Both triethanolamine and monensin cause a rapid increase in intracellular pH from 7.1 to 7.5 or 8.0. This pH increase precedes the subsequent morphological events of spermiogenesis. Triethanolamine or monensin must be present throughout spermiogenesis for all cells to form pseudopods, but once pseudopods are formed the inducers are unnecessary for subsequent motility. The pH induced spermiogenesis is inhibited by drugs that block mitochondria or glycolysis. Protease treatment can also induce spermiogenesis without increasing intracellular pH, apparently bypassing the pH-dependent steps in activation and the requirement for glycolysis. These results show that the initiation of spermiogenesis in C. elegans, like some steps in egg activation and the initiation of sea urchin sperm motility, can be induced by an increase in intracellular pH, but this pH change can be bypassed by proteolysis. ------------------- Key: 635 Medline: 11813735 Authors: Trent C;Tsung N;Horvitz HR Title: Egg-laying defective mutants of the nematode C. elegans. Citation: Genetics 104: 619-647 1983 Type: ARTICLE Genes: ced-3 daf-1 daf-3 daf-4 daf-5 daf-7 daf-8 daf-14 egl-1 egl-2 egl-3 egl-4 egl-5 egl-6 egl-7 egl-8 egl-9 egl-10 egl-11 egl-12 egl-13 egl-14 egl-15 egl-17 egl-18 egl-19 egl-20 egl-21 egl-23 egl-24 egl-25 egl-26 egl-27 egl-28 egl-29 egl-30 egl-31 egl-32 egl-33 egl-34 egl-35 egl-36 egl-37 egl-39 egl-40 her-1 lin-7 lin-10 lin-11 lin-12 lin-15 lin-17 lin-24 lin-25 lin-26 lin-28 lin-29 lin-31 mec-3 sdc-1 sup-17 tra-2 unc-6 unc-31 unc-40 unc-45 unc-51 unc-53 unc-59 unc-85 unc-86 unc-98 Abstract: We have isolated 144 mutants defective in egg-laying and have characterized 58 of these genetically, behaviorally and pharmacologically. Most of the other mutants proved to be alleles of previously identified genes that affect egg-laying. These 58 mutants define 40 new genes called egl, for egg-laying defective. The egl mutants vary with respect to the severity of their egg-laying defects and the presence of behavioral or morphological pleiotropies. We have defined five categories of mutants based on their responses to the pharmacological agents serotonin and imipramine, which stimulate egg-laying by wild-type hermaphrodites. Mutants in 19 egl genes failed to respond to both serotonin and imipramine and are likely to be defective in the functioning of the vulva or the sex muscles. Four mutants (in four different genes) lay eggs in response to serotonin but not imipramine and appear to be egg-laying defective because of defects in the "hermaphrodite-specific neurons" (HSN's), which provide major neural inputs to the vulval muscles. Three of these four were selected specifically for these drug responses. Alleles of 7 egl genes as well as 4 dauer constitutive (daf) genes lay eggs in response to both serotonin and imipramine. One egl mutant responds to imipramine but not serotonin. The remaining egl mutants show variable or intermediate responses to the drugs. Two of the HSN-defective mutants, egl-1 and her-1(n695), lack HSN cell bodies and appear to be expressing the normally male-specific program of HSN cell death. Whereas egl-1 appears to specifically affect HSN development, n695 has multiple morphological pleiotrophies, displaying partial transformation in the sexual phenotype of many cells and tissues. At least two of the egl mutants appear to be defective in the processing of environmental signals that modulate egg-laying and may define new components of the ------------------- Key: 636 Medline: 83273600 Authors: Karn J;Brenner S;Barnett L Title: Protein structural domains in the C. elegans unc-54 myosin heavy chain gene are not separated by introns. Citation: Proceedings of the National Academy of Sciences USA 80: 4253-4257 1983 Type: ARTICLE Genes: unc-54 Abstract: The 1,966-amino acid unc-54 myosin heavy chain sequence was determined from DNA sequence studies of the cloned gene. The gene is split by eight short introns, 48-561 base pairs long, and appears to lack a "TATA" box at its promoter. The physical map of the gene was aligned with the genetic map by locating two point mutations and three internal deletions: 0.01 map units correspond to approximately 5 kilobases. Comparison of the unc-54 protein sequence with the sequence of a second myosin heavy chain from nematode, indicates that the globular head sequence S-1 is more highly conserved than the alpha-helical coiled-coil rod. Major sites of proteolysis in S-1 are associated with variable sequences that have the characteristics of surface loops. In both genes there is no correlation between the positions of introns and the major protein structural ------------------- Key: 637 Medline: Authors: Johnson TE Title: Aging in C. elegans. Citation: "Review of Biological Research in Aging, Volume 1." Rothstein M, Adler W, Cristofalo V, Finch CE, Florini J and Martin G (eds), Alan R. Liss, NY. 1: 37-49 1983 Type: REVIEW Genes: axe-1 Abstract: In 1974, Sydney Brenner published an elegant paper that described the genetic system of Caenorhabditis elegans and led to its use in research on a wide variety of topics, including aging (Brenner, 1974). Its small size (1mm as an adult) and determinate cell lineage has allowed a description of the entire somatic cell lineage from the one-cell stage to the adult (Sulston and Horvitz, 1977; Deppe et al., 1978; Kimble and Hirsh, 1979; Suslton et al., personal communication). Its ease of culture makes it an organism of choice for studies of various aspects of anatomy and physiology, including muscle formation and function (Zengel and Epstein, 1980; Mackenzie and Epstein, 1980), cuticle formation (Cox et al, 1981), neuroanatomy (Ward et al, 1975; Ware et al, 1975; Sulston et al, 1975), and behavior (Dusenbery, 1980). Several genes have been cloned by recombinant DNA techniques ablation (Kimble, 1981; Laufer and von Ehrenstin, 1981) procedures, as well as most of the modern molecular techniques, are in use. ------------------- Key: 638 Medline: Authors: Yamaguchi Y;Murakami K;Furusawa M;Miwa J Title: Germline-specific antigens identified by monoclonal antibodies in the nematode C. elegans. Citation: Development, Growth & Differentiation 25: 121-131 1983 Type: ARTICLE Genes: Abstract: Of 27 monoclonal antibodies identified to react, by indirect immunofluorescent antibody staining, with specific cells and tissues of the nematode Caenorhabditis elegans, we report here three monoclonal antibodies pertaining to the gonadal tissues. One antibody defines an antigen that is distributed over the entire embryo at earlier development and later becomes unique to the gonad, including mature oocytes. The antigens recognized by the other two are distributed asymmetrically in the posterior region of the fertilized egg's cytoplasm destined to become the germline precursor cell. Each antigen is successively segregated only to the germline precursor cells of the developing embryo and, postembryonically, is uniquely localized around the germline cell nuclei of the larvae and ------------------- Key: 639 Medline: 83284540 Authors: Snutch TP;Baillie DL Title: Alterations in the pattern of gene expression following heat shock in the nematode C. elegans. Citation: Canadian Journal of Biochemistry & Cell Biology 61: 480-487 1983 Type: ARTICLE Genes: Abstract: Exposure of the nematode Caenorhabditis elegans to elevated temperatures induces the preferential synthesis of eight major polypeptides of approximate molecular weights 81 000, 70 000, 41 000, 38 000, 29 000, 19 000, 18 000, and 16 000. In pulse-labelled worms these peptides first appear at 29 degrees C and continue to be synthesized up to lethal temperatures. They are heat inducible at every stage of development. While temperature elevation induces the synthesis of the heat-shock polypeptides, the in vivo synthesis of most other proteins present before heat shock is suppressed. In contrast, in vitro translation of mRNA from heat-shocked worms shows no alteration from the pattern of normal 20 degrees C mRNAs except for the appearance of the heat-shock mRNAs. An in vitro study of RNA from control and heat-shocked dauer larvae shows that this developmental variant possesses little translatable mRNA but, upon heat shock, synthesizes a set of messages corresponding to the heat- shock polypeptides. The low background of this system will be especially useful in the analysis and purification of heat-shock mRNA for molecular cloning experiments. Extensive similarities between the Drosophila and C. elegans heat-shock responses are shown, including homology between the 70-kdalton heat-shock genes ------------------- Key: 640 Medline: 83246543 Authors: Rosenzweig B;Liao LW;Hirsh D Title: Sequence of the C. elegans transposable element Tc1. Citation: Nucleic Acids Research 11: 4201-4209 1983 Type: ARTICLE Genes: Abstract: The complete nucleotide sequence was determined for Tc1, a transposable element in the nematode Caenorhabditis elegans. The 1610- base-pair element terminates in 54-base-pair perfect inverted repeats and is flanked by a 2-base-pair duplication of the target sequence. The Tc1 sequence contains two long open reading frames on the same DNA strand but in different translational reading frames. The positions of transcriptional control sequences suggest that a single transcript is made, which could produce two polypeptides, 273 and 112 amino acids in length. These features, i.e. terminal repeats, target site duplication and open reading frames, make Tc1 similar to transposable elements from other species. ------------------- Key: 641 Medline: 83210028 Authors: Himmelhoch S;Zuckerman BM Title: C. elegans: Characters of negatively charged groups on the cuticle and intestine. Citation: Experimental Parasitology 55: 299-305 1983 Type: ARTICLE Genes: Abstract: Partial characterization of carboxyl, sulfate, and phosphate groups on the Caenorhabditis elegans cuticle and intestinal microvilli was achieved by en face labeling of floating cryosections at two pH levels and specific blockage of sulfate groups by Alcian blue. All negatively charged groups on the cuticle and intestinal microvilli labeled heavily at pH 7.2-7.4. Pretreatment to block sulfate groups followed by ferritin labeling at pH 7.2-7.4 gave a 35% reduction of binding on the cuticle and an 80% reduction in binding on the microvilli. At pH 1.8 or 2.5, only the sulfate groups labeled as shown by the complete abolition of labeling on the cuticle and the microvilli following blockage of the sulfate groups. Molecules with accessible sulfate groups were distributed in clusters throughout the cortical layer of the cuticle, were present in the struts of the median layer but were absent from the basal layer. The advantages of applying molecular probes to cryosections as compared to sections prepared by standard electron microscopical techniques are discussed. ------------------- Key: 642 Medline: 83240682 Authors: Johnson CD;Russell RL Title: Multiple molecular forms of acetylcholinesterase in the nematode C. elegans. Citation: Journal of Neurochemistry 41: 30-46 1983 Type: ARTICLE Genes: ace-1 ace-2 Abstract: Extracts of the nematode Caenorhabditis elegans contain five molecular forms of acetylcholinesterase (AChE) activity that can be separated by a combination of selective solubilization, velocity sedimentation, and ion-exchange chromatography. These are called form IA (5.2s), form IB (4.9s), form II (6.7s), form III (11.3s), and form IV (13.0s). All except form III are present in significant amounts in rapidly prepared extracts and are probably native; form III is probably derived autolytically from form IV. Most of forms IA and IB can be solubilized by repeated extractions without detergent, whereas forms II, III, and IV require detergent for effective solubilization and may therefore be membrane-bound. High salt concentrations are not required for, and do not aid in, the solubilization of these forms. For all forms, molecular weights and frictional ratios have been estimated by a combination of gel permeation chromatography and velocity sedimentations in both H2O and D2O. The molecular weight estimates range from 83,000 to 357,000 and only form II shows extensive asymmetry. The separated forms have been characterized with respect to substrate affinity, substrate specificity, inhibitor sensitivity, thermal inactivation, and detergent sensitivity. Judging by these properties, C. elegans is like other invertebrates in that none of its cholinesterase forms resembles either the "true" or the "pseudo" cholinesterase of vertebrates. However, internal comparison of the C. elegans forms clearly distinguishes forms IA, III, and IV as a group from forms IB and II; the former are therefore designated "class A" forms, the latter "class B" forms. Genetic evidence indicates that separate genes control class A and class B forms, and that these two classes overlap functionally. Several factors, including kinetic properties, molecular asymmetry, molecular size, and solubility, all suggest that a molecular model of the multiple cholinesterase forms observed in vertebrate electric organs probably does not apply in C. elegans. Potential functional roles and subunit structures of the multiple AChE forms within each C. elegans class are ------------------- Key: 643 Medline: Authors: Hirsh D;Files JG;Carr SH Title: Isolation and genetic mapping of the actin genes of C. elegans. Citation: "Muscle Development: Molecular and Cellular Control." Pearson M and Epstein HF (eds), Cold Spring Harbor Laboratory. : 77-86 1982 Type: REVIEW Genes: act-1 act-2 act-3 Abstract: The nematode Caenorhabditis elegans contains a small genome of 8 X 10*7 bp of DNA. The adult animal has 953 somatic cells whose complete embryonic and postembryonic cell lineages are known. Many are muscle cells or cells containing thin filaments. C. elegans is a self-fertilizing hermaphrodite that is convenient for genetic analyses, and a detailed genetic map has been constructed. Approximately 20 muscle genes have been identified on the basis of mutant phenotypes that include uncoordinated behavior and defective muscles. Among these 20 muscle genes, only 2 have been connected with functional gene products; unc-54 codes for a major myosin, and unc-15 codes for paramyosin. No actin gene has been identified in C. elegans. It is possible that one of the known muscle genes codes for actin, but actin loci may be difficult to detect genetically. For example, mutations in actin genes might be lethal or cryptic if multiple, identical genes are present. Nevertheless, the actin genes of C. elegans are important objects of study because actin is an abundant protein in C. elegans, because its synthesis is regulated developmentally in specific cell lineages, and because the genetic manipulation of actin genes seems feasible once these genes are recognized and mapped. We therefore began a search for the actin genes of C. elegans using nongenetic ------------------- Key: 644 Medline: Authors: Karn J;McLachlan AD;Barnett L Title: unc-54 myosin heavy-chain gene of C. elegans: Genetics, sequence, structure. Citation: "Muscle Development: Molecular and Cellular Control." Pearson M and Epstein HF (eds), Cold Spring Harbor Laboratory. : 129-142 1982 Type: REVIEW Genes: unc-15 unc-54 Abstract: The small soil nematode Caenorhabditis elegans is an attractive organism for the molecular study of muscle function and development because of its anatomical simplicity and suitability for genetic and biochemical analysis (Brenner 1974; Sulston and Horvitz 1977). The body-wall musculature of C. elegans is composed of 95 cell disposed in four quadrants, which run the length of the animal beneath the cuticle. The musculature is obliquely striated, and the sarcomeres are oriented parallel to the long axis of the animal. Since these cells represent a large reaction of the animal mass, isolation of contractile proteins is comparatively simple (Epstein et al. 1974; Waterston et al. 1974, 1977a; Harris and Epstein 1977; Mackenzie and Epstein 1980). Mutants affecting the characteristic pattern of motility of C. elegans can be easily identified, and microscopic examination of these "uncoordinated," or unc strains, in the living animal by polarized light microscopy or, more carefully, by electron microscopy has led to the identification of 22 genes that produce altered muscle phenotypes (Waterston et al. 1980; Zengel and Epstein 1980). Of these, two are known to code for major structural proteins of muscle: The unc-54 gene codes for the major heavy chain of myosin (Epstein et al. 1974; MacLeod et al. 1977b), whereas the un-15 gene codes for paramyosin, the core protein of the thick filaments (Waterston et al. 1974; MacLeod et al. 1977a; Harris and Epstein 1977). ------------------- Key: 645 Medline: Authors: Epstein HF;Berman SA;Miller DM III Title: Myosin synthesis and assembly in nematode body-wall muscle. Citation: "Muscle Development: Molecular and Cellular Control." Pearson M and Epstein HF (eds), Cold Spring Harbor Laboratory. : 419-427 1982 Type: REVIEW Genes: unc-15 Abstract: Myosin is the central piece in the protein machinery that produces muscle contraction. In this role, the myosin molecule must serve as an energy-transducing enzyme and as the major building block of the thick filament. In differentiated muscle cells, myosin is constantly being synthesized and assembled into thick filaments. Many issues regarding the processes of myosin synthesis and assembly in muscle remain unresolved. Is the synthesis and assembly of myosin coupled? Are additional protein components required for the assembly of myosin into native thick filaments? Do different myosin isoforms play distinct structural or functional roles within thick filaments? The combined approaches of protein biochemistry, immunology, and electron microscopy have proved useful in establishing our present knowledge concerning the roles of myosin within muscle. The nematode Caenorhabditis elegans offers several experimental advantages in addition to these time-honored methods that may provide further insights concerning the process of myosin synthesis and assembly. This animal has an elegantly simple and well-defined development and anatomy of body-wall muscle cells. Genetic analysis has characterized hundreds of specific mutants in over 20 genes affecting the development, structure, and function of body-wall muscle cells. This genetic approach, in combination with biochemical, immunological, and morphological methods, promises to offer significant ------------------- Key: 646 Medline: 84002251 Authors: Greenwald IS;Sternberg PW;Horvitz HR Title: The lin-12 locus specifies cell fates in C. elegans. Citation: Cell 34: 435-444 1983 Type: ARTICLE Genes: lin-12 sup-7 eT1 mnDp37 Abstract: We describe two classes of mutations in the lin-12 locus of the nematode Caenorhabditis elegans. Ten semidominant mutations (lin- 12[d]) appear to elevate the level of lin-12 activity. Thirty-two recessive alleles (lin-12[0]), including two amber mutations, appear to eliminate gene activity. The lin-12(d) and lin-12(0) mutations result in reciprocal homeotic transformations in the fates of defined cells in several different tissues. Gene dosage studies suggest that a high level of lin-12 activity specifies one cell fate and a low level specifies an alternative fate. Temperature-shift experiments indicate that lin-12 acts at the time cell fate is determined in wild type. We propose that lin-12 functions as a binary switch to control decisions between alternative cell fates during C. elegans development. ------------------- Key: 647 Medline: 84002255 Authors: Miller DM III;Ortiz I;Berliner GC;Epstein HF Title: Differential localization of two myosins within nematode thick filaments. Citation: Cell 34: 477-490 1983 Type: ARTICLE Genes: unc-54 Abstract: The body wall muscle cells of the nematode, Caenorhabditis elegans, contain two unique types of myosin heavy chain, A and B. We have utilized an immunochemical approach to define the structural location of these myosins within body wall muscle thick filaments. By immunofluorescence microscopy, myosin B antibodies label the thick filament-containing A-bands of body wall muscle with the exception of a thin gap at the center of each A-band, and myosin A antibodies react to form a medial fluorescent stripe within each A-band. The complexes of these monoclonal antibodies with isolated thick filaments were negatively stained and studied by electron microscopy. The myosin B antibody reacts with the polar regions of all filaments but does not react with a central 0.9 um zone. The myosin A antibody reacts with a central 1.8 um zone in all filaments but does not react with the polar regions. ------------------- Key: 648 Medline: Authors: Ohba K;Ishibashi N Title: A factor inducing dauer juvenile formation in C. elegans. Citation: Nematologica 28: 318-325 1982 Type: ARTICLE Genes: Abstract: Caenorhabditis elegans were induced to form true dauer juveniles by the material lyophilized from a water solution in which living C. elegans (1 g fresh weight/50 ml distilled water) were incubated for 24 hr at 20C. The material best induced dauer formation at 23C, pH 6.0, 2% agar with 1/8 strength of Sayre et al.'s axenic medium. Overcrowding itself exerted no major effect. First and 2nd stage juveniles most actively secreted the dauer inducing substance into the incubating medium. Neither dauer juveniles nor other nematodes such as Bursaphelenchus xylophilus or Neoaplectana carpocapsae secreted the active substance. ------------------- Key: 649 Medline: 84026513 Authors: Strome S;Wood WB Title: Generation of asymmetry and segregation of germ-line granules in early C. elegans embryos. Citation: Cell 35: 15-25 1983 Type: ARTICLE Genes: emb-27 fem-2 fer-1 zyg-9 Abstract: Germ-line granules in C. elegans embryos (P granules) can be visualized by immunofluorescence microscopy using a monoclonal antibody. In mutant zygotes with abnormal spindle orientations and in wild-type zygotes treated with the microtubule inhibitors nocodazole, colcemid, vinblastine, and griseofulvin, both P-granule segregation to the posterior pole and the concomitant pseudocleavage occur apparently normally, but the normally concurrent migration of the pronuclei is inhibited. Conversely, treatment of wild-type embryos with the microfilament inhibitors cytochalasins D and B inhibits P- granule segregation and pseudocleavage, as well as other manifestations of polarity, without preventing pronuclear migration. The results suggest that P-granule segregation does not require either the spindle or cytoplasmic microtubules, but that this process as well as generation of other asymmetries does require cytoskeletal functions ------------------- Key: 650 Medline: 84062370 Authors: Albert PS;Riddle DL Title: Developmental alterations in sensory neuroanatomy of the C. elegans dauer larva. Citation: Journal of Comparative Neurology 219: 461-481 1983 Type: ARTICLE Genes: Abstract: The anterior sensory ultrastructure of the C. elegans dauer larva was examined in several specimens and compared with that of the second- stage (L2) larva, which immediately precedes the dauer stage. In some instances comparisons were made with L3, postdauer L4, and adult stages. Whereas sensory structures in different nondauer stages closely resemble each other, including the inner labial sensilla, amphids, and deirids. The relative positions of the afferent tips of the two types of inner labial neurons are reversed in the dauer stage compared to the L2 and postdauer L4 stages. Inner labial neuron 1 rather than neuron 2 is more anterior in each of the six sensilla, and neuron 1 has an enlarged tip. The neuron 2 cilia are only one- third as long as those in the L2. Amphidial neurons c, d, g, and i and the amphidial sheath cell are altered in shape or position in the dauer stage. Neurons g and i are displaced posteriorly within the dauer amphidial channel. Neuron d has significantly more microvillar projections than do the d cells in L2, L3, or postdauer L4 larvae. Winglike processes of dauer neuron c form a 200 degrees-240 degrees arc in transverse section, including extensive overlap of the two cells. The arc in an L2 seldom spans more than 100 degrees, and overlap does not occur. While L2 larvae possess two separate bilateral amphidial sheath cells, the left and right sheath cells are often continuous in the dauer larva. Deirid sensory dendrites exhibit a dauer-specific structure and orientation. The tip of each neuron is attached to the body wall cuticle by a substructure not observed in L2 or postdauer L4 stages, and the neurons are oriented parallel to the longitudinal axis of the dauer larva. The deirid sensory terminals are oriented perpendicular to the cuticle in other stages. Reversible alterations in neural structure are discussed in ------------------- Key: 651 Medline: 84010852 Authors: McLachlan AD Title: Analysis of gene duplication repeats in the myosin rod. Citation: Journal of Molecular Biology 169: 15-30 1983 Type: ARTICLE Genes: Abstract: The helical coiled-coil region of the myosin rod in the nematode Caenorhabditis elegans is a repetitive sequence 1094 amino acids long which contains 39 repeats of a 28-residue pattern. The repeats are extremely significant when compared with the statistical distributions expected, first for random sequences, and then for sequences with a typical seven-residue coiled-coil periodicity. New and improved statistical tests are used. The repeats are stronger in the first 350 residues of the rod (fragment S-2) than in the remainder. The corresponding DNA sequence of the unc-54 gene shows the same features, but they are less significant when judged by the number of identical bases than are the amino acid similarities, as measured by Dayhoff scores. The rod sequence shows strong evidence for a longer repeat unit of 196 residues, which may be related to the cross-bridge spacing of 143 A in muscle. ------------------- Key: 652 Medline: Authors: Kenyon CJ Title: Pattern, symmetry and surprises in the development of C. elegans. Citation: Trends in Biochemical Sciences 8: 349-351 1983 Type: REVIEW Genes: Abstract: In the course of metazoan development, the generation of multiple cell types from a single cell requires the repeated creation of daughter cells that differ from one another. This production of non-equivalent daughter cells can be called a developmental decision, or switch. The task of understanding development is that of determining how these switches are arranged in space and time, and then how they operate at a molecular level. ------------------- Key: 653 Medline: 84005467 Authors: Sulston JE;Schierenberg E;White JG;Thomson JN Title: The embryonic cell lineage of the nematode C. elegans. Citation: Developmental Biology 100: 64-119 1983 Type: ARTICLE Genes: Abstract: The embryonic cell lineage of Caenorhabditis elegans has been traced from zygote to newly hatched larva, with the result that the entire cell lineage of this organism is now known. During embryogenesis 671 cells are generated; in the hermaphrodite 113 of these (in the male 111) undergo programmed death and the remainder either differentiate terminally or become postembryonic blast cells. The embryonic lineage is highly invariant, as are the fates of the cells to which it gives rise. In spite of the fixed relationship between cell ancestry and cell fate, the correlation between them lacks much obvious pattern. Thus, although most neurons arise from the embryonic ectoderm, some are produced by the mesoderm and a few are sisters to muscles; again, lineal boundaries do not necessarily coincide with functional boundaries. Nevertheless, cell ablation experiments (as well as previous cell isolation experiments) demonstrate substantial cell autonomy in at least some sections of embryogenesis. We conclude that the cell lineage itself, complex as it is, plays an important role in determining cell fate. We discuss the origin of the repeat units (partial segments) in the body wall, the generation of the various orders of symmetry, the analysis of the lineage in terms of sublineages, and evolutionary implications. ------------------- Key: 654 Medline: 84032491 Authors: Sanford T;Golomb M;Riddle DL Title: RNA polymerase II from wild type and alpha-amanitin-resistant strains of C. elegans. Citation: Journal of Biological Chemistry 258: 12804-12809 1983 Type: ARTICLE Genes: ama-1 let-56 nT1 Abstract: DNA-dependent RNA polymerases I, II, and III have been isolated from the soil nematode, Caenorhabditis elegans, and RNA polymerase II has been partially purified. The sensitivities of these enzymes to alpha- amanitin resemble those of the cognate enzymes from vertebrates. RNA polymerase II from C. elegans is 50% inhibited by 7 ng/ml of the amatoxin and RNA polymerase III by 80 micrograms/ml, whereas RNA polymerase I is insensitive to 500 micrograms/ml. We have obtained mutants of C. elegans which can grow and reproduce in concentrations of alpha-amanitin which arrest development of wild type animals. One of these mutants (DR432) has an altered RNA polymerase II which in partially purified extracts is 150 times less sensitive to the drug than the wild type enzyme. The mutation, ama-1(m130), in DR432 is dominant and maps near dpy-13 on linkage group IV. RNA polymerase II isolated from ama-1/+ heterozygotes contains equal proportions of two components, corresponding in alpha-amanitin sensitivity to the enzymes from DR432 and wild type. Thus, ama-1 appears to affect a subunit of RNA polymerase II. ------------------- Key: 655 Medline: Authors: Roberts TM Title: Crawling C. elegans spermatozoa contact the substrate only by their pseudopods and contain 2-nm filaments. Citation: Cell Motility 3: 333-347 1983 Type: ARTICLE Genes: him-5 Abstract: The locomotion of C. elegans spermatozoa resembles, in many respects, the crawling movements of other eukaryotic cells. However, these sperm contain surprising little actin, which plays no apparent role in this cell's motility. Electron microscopy has revealed that crawling spermatozoa retain a strict morphological polarity so that the organelle-filled cell body is separated from the pseudopod by an array of ctyoplasmic laminar membranes. When sperm crawl only the pseudopod contacts the substrate; the cell body is either pulled behind or carried on top of the rear portion of the pseudopod. Fingerlike projections which extend forward from the leading edge of the psuedopod initiate contact with the substrate. The underside of the pseudopod exhibits areas of close (40 nm separation) membrane-substrate association with intervening areas of wide (up to 300 nm) membrane-substrate gaps. The pseudopod cytoplasm contains 2-nm filaments but no filamentous actin has been observed. These 2-nm filaments were detected in thin sections of crawling cells and in negative-stained remnants of spermatozoa disrupted by either hypotonic buffer or Triton X-100. The filaments are found both free in the cytoplasm and closely associated with the cytoplasmic face of the plasma membrane and are usually oriented along the long axis of the cell. Neither the identity nor the function of these filaments has been established although their location and orientation suggest ------------------- Key: 656 Medline: 84064866 Authors: Burke DJ;Ward S Title: Identification of a large multigene family encoding the major sperm protein of C. elegans. Citation: Journal of Molecular Biology 171: 1-29 1983 Type: ARTICLE Genes: fem-1 him-5 Abstract: DNA fragments corresponding to genes encoding the MSP of Caenorhabditis elegans sperm have been isolated by recombinant DNA techniques. Analyses of individual genomic clones suggest that there are multiple MSP genes that are dispersed in the genome. From restriction enzyme digests of genomic DNA fractionated and hybridized with an MSP complementary DNA probe, there appear to be more than 30 MSP genes in the genome. Despite the occurrence of this large dispersed multigene family, the MSP messenger RNA from both males and hermaphrodites is homogene in size. There are at least three different proteins of identical molecular weight but different isoelectric point that cross-react with anti-MSP antisera. Each protein is a primary translation product with no detectable post- translational modifications, suggesting that at least three of the MSP genes are expressed. ------------------- Key: 657 Medline: 84056432 Authors: Vanfleteren JR;Van Beeumen JJ Title: Nematode chromosomal proteins-III. Some structural properties of the histones of C. elegans. Citation: Comparative Biochemistry & Physiology 76B: 179-184 1983 Type: ARTICLE Genes: Abstract: The histones of Caenorhabditis elegans (Nematoda) have been identified by correlating criteria of electrophoresis and amino acid composition with the five main histones from calf thymus. C. elegans H1(1) consists of at least two subtypes with approximate molecular weights of 20,000 and 18,500 daltons as resolved by SDS polyacrylamide gel electrophoresis. They are some 10% smaller than the two subtypes of calf histone H1. The differences are also corrobated by the amino acid composition of the nematode and calf H1 complements. Nematode H2A resembles calf H2A in chromatographic and electrophoretic properties and in the amino acid composition, although it lacks histidine, which seems to be replaced by lysine. Like calf H2A, it is dimorphic as shown by Triton/acid/urea polyacrylamide gel electrophoresis. The H2B complement from C. elegans consists of two proteins with a molecular weight of approximately 12,500. They can be separated by ion-exchange chromatography, but they are very analogous to each other and to calf H2B in amino acid composition. Each form is also resolved into two more subtypes by Triton/acid/urea polyacrylamide gel electrophoresis. Nematode H3 resembles calf thymus H3 in its electrophoretic behaviour; three subfractions can be distinguished in Triton/acid/urea gels. C. elegans H4 is very similar to calf H4 in its chromatographic, electrophoretic and solubility properties, but differs significantly in composition. The meaning of this difference is discussed with regard to the generally observed stringent conservation of H4 sequences between distantly related species. ------------------- Key: 658 Medline: 84038230 Authors: Klass M;Nguyen PN;Dechavigny A Title: Age correlated changes in the DNA template in the nematode C. elegans. Citation: Mechanisms of Ageing & Development 22: 253-263 1983 Type: ARTICLE Genes: fer-15 Abstract: Analysis of DNA from the nematode Caenorhabditis elegans demonstrated a number of significant age-correlated changes. The number of single- strand breaks as assayed by an in vitro assay procedure using Escherichia coli DNA polymerase I increased significantly with age. There was also an exponential increase in the amount of 5- methylcytosine in C. elegans DNA as the worm matured and aged. Furthermore, DNA isolated from older worms exhibited reduced transcriptional capacity when assayed in a HeLa cell in vitro transcription system. Finally, a biological assay to determine age- correlated changes in the DNA of aging sperm demonstrated a significant reduction in the capacity of the sperm to support zygotic development as the age of the male increased. These findings demonstrated significant age-correlated alterations and modifications occurring in the DNA template of the nematode, and their implications to the aging process are discussed. ------------------- Key: 659 Medline: 84038232 Authors: Klass MR Title: A method for the isolation of longevity mutants in the nematode C. elegans and initial results. Citation: Mechanisms of Ageing & Development 22: 279-286 1983 Type: ARTICLE Genes: fer-15 Abstract: The free-living nematode Caenorhabditis elegans is used as a genetically manipulable experimental system for the study of aging. Utilizing a temperature-sensitive sterile strain with a normal life span, a method is described for the isolation of mutant strains with significantly increased life spans. Eight mutant strains were isolated each having increased life spans. Two mutant strains were spontaneous dauer formers, accounting for their increased longevity. Another was chemotaxis-defective, causing reduced food intake which could account for its increased life span. Five mutants suffered from varying degrees of paralysis affecting their rate of pharyngeal pumping and food ingestion. The high correlation of the decreased rate of food ingestion of these mutants with their increased longevity is interpreted as indicating that the increased longevity is most likely due to reduced caloric intake. These results appear to indicate that specific life span genes are extremely rare or, alternatively, life span is controlled in a polygenic fashion. ------------------- Key: 660 Medline: Authors: Starck J;Gibert M-A;Brun J;Bosch C Title: Ribosomal RNA synthesis and processing during oogenesis of the free living nematode C. elegans. Citation: Comparative Biochemistry & Physiology 75B: 575-580 1983 Type: ARTICLE Genes: Abstract: 1. The pattern of RNA synthesis during oogenesis of Caenorhabditis elegans was examined after in vitro labelling of the extruded gonads by ultrastructural radioautography and gel electrophoresis. 2. Nuclear RNA synthesis was found most active during pachytene stage while cells, in late diakinesis, do not transcribe RNA. 3. Labelled RNA molecules accumulate into the cytoplasm during all stages of oogenesis. 4. Most of these molecules apparently result from the processing of large molecular weight RNA into mature ribosomal RNA components. 5. The ribosomal RNA processing studied in vitro differs however to some extent from that observed in vivo. ------------------- Key: 661 Medline: 83262746 Authors: Isnenghi E;Cassada R;Smith K;Denich K;Radnia K;von Ehrenstein G Title: Maternal effects and temperature-sensitive period of mutations affecting embryogenesis in C. elegans. Citation: Developmental Biology 98: 465-480 1983 Type: ARTICLE Genes: emb-5 emb-6 emb-9 emb-11 emb-12 emb-13 emb-14 emb-15 emb-16 emb-17 emb-18 emb-19 emb-20 emb-21 emb-22 emb-23 emb-24 emb-25 emb-26 emb-27 emb-28 emb-29 emb-30 emb-31 emb-32 emb-33 emb-34 emb-35 let-2 zyg-2 Abstract: We have used standard tests to investigate the nature of gene expression of a new set of temperature-sensitive mutants defining 30 emb genes (essential for embryogenesis) in the nematode Caenorhabditis elegans. The mode of gene expression as determined by progeny tests for parental effects divides the genes into four classes. For 18 genes maternal gene expression is necessary and sufficient for normal embryogenesis; for 2 genes zygotic expression is necessary and sufficient; for 7 genes either maternal or zygotic expression is sufficient; for 3 genes both maternal and zygotic expression are necessary. One mutant displayed partial paternal sufficiency. The results of temperature-shift experiments define two "execution stages," corresponding to the limits of the temperature- sensitive period (TSP), and indicate the nature and the time of action or synthesis of the gene products. Most of the maternally expressed genes have very early execution stages indicating translation before fertilization, but some are temperature sensitive late in embryogenesis. Early execution stages for 2 zygotically necessary genes demonstrate that the zygotic genome can be active in the earliest stages of embryogenesis. All taken together, the mode of gene expression, TSP, and arrest stage (terminal phenotype) allow us to classify functionally and begin to order the genes essential for embryogenesis. The results indicate a preeminent role for maternal genes and gene products in embryogenesis, in agreement with the results of ------------------- Key: 662 Medline: 83296078 Authors: Bolanowski MA;Jacobson LA;Russell RL Title: Quantitative measures of aging in the nematode C. elegans: II. Lysosomal hydrolases as markers of senescence. Citation: Mechanisms of Ageing & Development 21: 295-319 1983 Type: ARTICLE Genes: fer-15 Abstract: In an attempt to provide additional quantitative markers of senescence in the nematode Caenorhabditis elegans, we have identified age-dependent increases in four lysosomal enzymes: acid phosphatase, beta-N-acetyl-D-glucosaminidase, beta-D-glucosidase, and alpha-D- mannosidase. These enzymes were judged to be lysosomal on the basis of their resemblance to analogous mammalian lysosomal enzymes with regard to subcellular fractionation, lectin binding, Km, molecular weights, inhibitor sensitivities, and pH optima. In nematode populations which had a median lifespan of 8.9 +/- 0.7 days and a maximum lifespan of 14-16 days, we observed the following increases in acid hydrolase activities per animal from day 3 (early adulthood) to day 10: (1) up to 2.5-fold for acid phosphatase; (2) 8-fold for beta-N-acetyl-D-glucosaminidase; (3) 9-fold for beta-D-glucosidase; and (4) 4-fold for alpha-D-mannosidase. Three forms of acid phosphatase and two forms of beta-D-glucosidase were separated by ion- exchange chromatography, but in each case only one form of the enzyme was primarily responsible for the age-dependent increase in total activity: acid phosphatase I increased 18-fold, while beta-D- glucosidase I increased 100-fold. By contrast, there were only slight age-dependent changes in choline acetyltransferase, acetylcholinesterase, or alpha-D-glucosidase activities after early adulthood. The age-dependent increases in acid phosphatase, beta-N- acetyl-D-glucosaminidase, beta-D-glucosidase, and alpha-D-mannosidase activities are sufficiently large and reproducible to be useful quantitative markers of senescence in C. elegans. ------------------- Key: 663 Medline: 84170641 Authors: Hartman PS Title: UV irradiation of wild type and radiation-sensitive mutants of the nematode C. elegans: Fertilities, survival, and parental effects. Citation: Photochemistry and Photobiology 39: 169-175 1984 Type: ARTICLE Genes: rad-1 rad-2 rad-3 rad-7 Abstract: Survival after UV irradiation was examined in wild type and four radiation-sensitive (rad) mutants of Caenorhabditis elegans. Synchronous populations were employed to assess radiation sensitivities at different developmental stages. In addition, the effects of irradiation on male and hermaphrodite fertilities were measured. Wild-type sensitivity was maximal early in embryogenesis. Different age-dependent patterns of radiation sensitivity were obtained with the rad mutants. The effects of parental genotype were also tested. A parental wild-type allele was capable of quickly elevating the radiation resistance of embryos derived from homozygous rad hermaphrodites. In a second parental-effect test, homozygous rad embryos displayed greater radiation resistance when derived from heterozygous rather than homozygous hermaphrodites. The results indicate that radiation sensitivity in this metazoan is determined by complex interactions of gene ------------------- Key: 664 Medline: 84132366 Authors: Findeis PM;Barinaga CJ;Willett JD;Farwell SO Title: Age-synchronous culture of C. elegans: Technique and applications. Citation: Experimental Gerontology 18: 263-275 1983 Type: ARTICLE Genes: Abstract: The inclusion of mobility to an age synchrony method and the development of an inexpensive filter device resulted in a natural model aging system without resorting to invasive chemical techniques. Large or small cohorts of nematodes with less than 1% offspring contamination are possible. The filter/mobility method is compared to other methods using the same strain and culture temperature. The applicability of the method is shown with a variety of parameters, and a previously reported parameter of aging in nematodes, i.e., specific gravity, is shown not to be an aging parameter of Caenorhabditis elegans. ------------------- Key: 665 Medline: 84109493 Authors: Meneely PM;Wood WB Title: An autosomal gene that affects X chromosome expression and sex determination in C. elegans. Citation: Genetics 106: 29-44 1984 Type: ARTICLE Genes: dpy-21 her-1 him-5 tra-1 tra-2 tra-3 ctDp1 mnDp1 mnDp8 mnDp9 stDp2 mnDp10 mnDp25 mnDp27 mnDp33 Abstract: Recessive mutant alleles at the autosomal dpy-21 locus of C. elegans cause a dumpy phenotype in XX animals but not in XO animals. This dumpy phenotype is characteristic of X chromosome aneuploids with higher than normal X to autosome ratios and is proposed to result from overexpression of X-linked genes. We have isolated a new dpy-21 allele that also causes partial hermaphroditization of XO males, without causing the dumpy phenotype. All dpy-21 alleles show hermaphroditization effects in XO males that carry a duplication of part of the X chromosome and also partially suppress a transformer (tra-1) mutation that converts XX animals into males. Experiments with a set of X chromosome duplications show that the defects of dpy- 21 mutants can result from interaction with several different regions of the X chromosome. We propose that dpy-21 regulates X chromosome expression and may be involved in interpreting X chromosome dose for the developmental decisions of both sex determination and dosage compensation. ------------------- Key: 666 Medline: Authors: Hodgkin J Title: X chromosome dosage and gene expression in C. elegans: Two unusual dumpy genes. Citation: Molecular & General Genetics 192: 452-458 1983 Type: ARTICLE Genes: dpy-21 dpy-22 dpy-23 dpy-26 emb-26 fem-1 her-1 him-8 sup-5 tra-1 sDf2 Abstract: The phenotypes caused by mutations in two autosomal genes of the nematode Caenorhabditis elegans, dpy-21 V and dpy-26 IV, are markedly affected by X chromosome dosage, independent of sexual phenotype. At high X chromosome to autosome ratio, in 2A:3X animals, these dumpy mutations are lethal; at intermediate ratio, in 2A:2X animals, they cause dumpiness or lethality; at low ration 2A:1X animals they cause neither dumpiness nor lethality. One gene, dpy-26, exhibits a strong maternal effect. Interactions between these genes and two major sex-determining genes her-1 V and tra-1 III have been examined. The dumpy mutations partly suppress the masculinization of tra-1 2A:2X animals and also increases the fertility of most her-1 2A:1X hermaphrodites. It is suggested that these dumpy genes are involved in X chromosome dosage compensation, and in some aspect of sexual differentiation. The dpy-26 gene is compared with a similar Drosophila gene, daughterless. ------------------- Key: 667 Medline: 84109239 Authors: Albertson DG Title: Formation of the first cleavage spindle in nematode Citation: Developmental Biology 101: 61-72 1984 Type: ARTICLE Genes: zyg-9 Abstract: The distribution of microtubules and microtubule organizing centers in the events leading up to the establishment of the first asymmetric cleavage furrow in nematode embryos was followed using indirect immunofluorescence of antibodies to tubulin. Oocytes arrest in meiotic prophase then undergo two meiotic reduction divisions after fertilization. At both of these divisions barrel-shaped spindles were observed. Initially a single microtubule organizing center was seen adjacent to the sperm pronucleus following fertilization in Caenorhabditis elegans, but later two sperm asters were distinguished. These increased in size as the egg pronucleus migrated toward the sperm pronucleus and reached maximum size, with fascicles of microtubules extending to the cortex, once the pronuclei had become juxtaposed. The first cleavage spindle formed following rotation and migration of the juxtaposed pronuclei back toward the center of the embryo. The distribution of microtubules in a temperature-sensitive mutant that fails in both pronuclear migration and rotation was also examined. Asters in the mutant embryos at the nonpermissive temperature contained only short microtubules suggesting that the morphology of the asters is important for directing the movement of the pronuclei. In Panagrellus redivivus sperm asters were not detected by anti-tubulin staining until the female pronucleus had migrated to the centrally placed sperm pronucleus. Asters then increased in size and formed the first cleavage spindle. ------------------- Key: 668 Medline: 84109231 Authors: Schierenberg E Title: Altered cell-division rates after laser-induced cell fusion in nematode embryos. Citation: Developmental Biology 101: 240-245 1984 Type: ARTICLE Genes: Abstract: In embryos of Caenorhabditis elegans adjacent cells belonging to different cell lines have been fused by disrupting the cell membrane between them with a single laser pulse. This leads to cytoplasmic mixing. Synchronous mitoses of the two nuclei result in the direct formation of four cells. Subsequent alteration of the cell cycle rhythm in some specific--but not all--descendants of the fused cells is observed, leading to abnormal cell patterns and often embryonic arrest. ------------------- Key: 669 Medline: 84106814 Authors: Traboni C;Ciliberto G;Cortese R Title: Mutations in box B of the promoter of a eukaryotic tRNApro gene affect rate of transcription, processing, and stability of the transcripts. Citation: Cell 36: 179-187 1984 Type: ARTICLE Genes: Abstract: We have constructed a series of single and double base-pair-substitution mutants in and around the second component (Box B) of the promoter of a tRNA(Pro) gene from C. elegans. Their analysis in in vivo and in vitro transcriptional systems establishes the importance of single nucleotides in the promotion of transcription. Most mutants in the region coding for the T*CG stem-loop show a reduced gene expression associated with lack of processing of the primary transcriptional products; in the oocytes these are rapidly degraded, with a half-life considerably shorter than that of wild-type tRNA molecules. In contrast, mutations in the DNA region coding for anticodon stem-loop do not alter the efficiency of transcription or the processing of the transcripts. ------------------- Key: 670 Medline: Authors: Blonston G Title: To build a worm. Citation: Science 84 5: 63-67 1984 Type: NEWS Genes: Abstract: In a dimly lit laboratory room in Gottingen, West Germany, Einhard Schierenberg bent his long, angular frame over his microscope, watching and counting, recording what he saw on charts and videotapes, hour upon hour, day after day, intermittently for six years. Five hundred miles away in a tiny, starkly equipped cubbyhole in Cambridge, England, John Sulston was doing the same thing, hunched over his microscope, earphones on his head to block any sound that might divert him from the image in his eyepiece. Sometimes he would sit watching all day long, diligently marking in a notebook with his colored pens. Schierenberg and Sulston were learning, cell by cell, how to build a worm. ------------------- Key: 671 Medline: 84206573 Authors: Sulston JE Title: Neuronal cell lineages in the nematode C. elegans. Citation: Cold Spring Harbor Symposia on Quantitative Biology 48: 443-452 1983 Type: REVIEW Genes: ced-3 unc-86 Abstract: One of the most attractive properties of the small nematode Caenorhabditis elegans is that the divisions, migrations, and deaths of all its cells can be followed continuously in living individuals from conception to maturity. By means of Nomarski differential interference contract microscopy, the entire cell lineage of the animal has been traced and has been related to the anatomy as reconstructed by electron microscopy. The early embryonic lineages were accurately described at the turn of the century, but, dependent as the observations then were upon comparisons between embryos fixed and stained at different ages, they could not be extended to later divisions and cell movements, or to postembryonic development. In the assignments of early embryonic cells to tissues, the findings of these pioneers have broadly been confirmed; in the later lineages, however, an unpredicted complexity of detail has emerged. In this review, my aim will be to summarize the principal findings concerning the ontogeny of the nervous system. Special attention will be paid to the embryonic stage, postembryonic neurogenesis having been recently reviewed by Horvitz. Before proceeding to an examination of the actual data, it is well to ask: Does the lineage have any significance beyond mere cell proliferation? To go some way towards answering this question, a number of cell ablation experiments, in which chosen cells are killed by means of a laser microbeam, have been carried out. Only a small proportion of the technically feasible experiments have been performed, but on the basis of this limited sample it appears that the nematode is highly mosaic in character: With certain well-defined exceptions, killed cells are not replaced from any other source and the differentiation of their neighbors is unaffected. Thus, if a given precursor is killed, subsequent examination of the animal reveals in most cases that all the cells usually derived from that precursor are missing and that all other cells are present. Particular examples of such experiments are described below; for the moment, it is sufficient to note that the general bona fides of the lineage, as an instrument of specific cell ------------------- Key: 672 Medline: 84206575 Authors: Horvitz HR;Sternberg PW;Greenwald IS;Fixsen W;Ellis HM Title: Mutations that affect neural cell lineages and cell fates during the development of the nematode C. elegans. Citation: Cold Spring Harbor Symposia on Quantitative Biology 48: 453-463 1983 Type: REVIEW Genes: ced-1 ced-2 ced-3 lin-1 lin-4 lin-5 lin-6 lin-8 lin-9 lin-12 lin-14 lin-15 lin-22 lin-26 lin-28 lin-29 lin-32 nuc-1 unc-59 unc-83 unc-84 unc-85 unc-86 Abstract: We have described 19 genes that affect neural cell lineages and cell fates during the development of C. elegans. These genes differ markedly in the nature, breadth, and specificity of their effects. Their only obvious common characteristic is that they all lack specificity for the nervous system, affecting both neural and nonneural development. For some of these genes (lin-5, lin-6, unc-59, unc-85), this nonspecificity probably reflects a general utilization of their products in cellular replication. In contrast, most of these genes appear to be highly specific in their effects, but their specificity is not on the basis of cell type but rather on the basis of some particular aspect of development. Specifically, unc-83 and unc-84 mutations affect certain precursor cells that generate both neural and nonneural descendants; lin-22 and lin-26 mutants lead to the generation of supernumerary neural cells with a concomitant loss of nonneural cells; lin-4, lin-14, lin-28, and lin-29 mutants perturb global aspects of developmental timing, altering the time of appearance (or preventing the appearance) of both neural and nonneural cells; lin-1, lin-8, lin-9, and lin-15 mutations affect the cell lineages of certain nonneuron -producing ectoblasts in hermaphrodites and of homologous neuron-producing ectoblasts in males; lin-12 mutations affect many sets of nonidentical homologs (cells of similar lineage history that express different fates), only some of which are neural; ced-3 mutations prevent all programmed cell deaths, again only some of which are neural. Of these 19 genes, only unc-86 is specific for neural as opposed to nonneural cell lineages. However, some unc-86 mutants are abnormal in chromosome segregation at meiosis, indicating that this gene also may affect nonneural aspects of development. One implication of these observations is that genes (and molecules) involved in neural development are likely to function in nonneural development as well. The genes lin-22, lin-12, unc-86, and ced-3 may play decision-making roles during C. elegans neurogenesis, as mutations in each of these genes cause specific transformations in the fates of particular cells. These genes and others like them may act within a hierarchy to effect decisions at different levels within cell lineages. For example, lin-22 animals display transformations affecting entire postembryonic cell lineages, unc-86 animals are altered at an intermediate level of certain cell lineages, and ced-3 animals are affected only in the ultimate fates of cells produced by terminal cell divisions.(ABSTRACT TRUNCATED AT 400 WORDS) ------------------- Key: 673 Medline: Authors: Zuckerman BM Title: The free-living nematode C. elegans as a rapid screen for compounds to retard aging. Citation: "Intervention in the Aging Process, Part B." Regelson W and Sinex FM (eds), Alan R. Liss, NY. : 275-285 1983 Type: REVIEW Genes: Abstract: The advantages of the free-living nematode Caenrohabditis elegans as a model for pharmacologic, toxicant and anthelmintic testing have become apparent to many companies, and the application of this organism as a primary screen for test compounds or toxic agents has expanded rapidly. It is appropriate to briefly summarize some of this nematode's qualities, to invoke an appreciation of this elegant system. As true of many invertebrate test organisms, C. elegans is small (about 1 mm X 40 u at maturity) and has a short life cycle: reproduction starts on day 3-4, ceases by day 14 and by day 25 it dies. Thus, for aging studies, all the symptoms of senescence are compressed into a short time period. In addition, this nematode has a small, fixed number of cells (about 830 at maturity) and differentiated organ systems: nervous, excretory, muscular, digestive and reproductive. The preceding characteristics are not unique in invertebrate model systems and their enumeration fails to explain the increasing popularity of C. elegans as a test organism. To understand this phenomenon several additional facts must be emphasized. First, the selection of C. elegans for detailed studies on the genetic control and regulation of behavior and developmental processes has fostered a wealth of knowledge on its neuroanatomy, cell lineages, biochemistry and behavior. There is now undoubtedly more accumulated knowledge on C. elegans than on any other multicellular creature. It is also the largest metazoan which can be continuously cultured on a chemically defined medium, and though most studies have proceeded on undefined media or in monoxenic culture (utilizing a bacterium as a food source), this property can be exploited for precise nutritional studies. In regard to aging studies, the question of relevance of aging in the nematode to that in mammals has been answered in respect to some parameters which characterize senescence in humans, and further study will define other features of aging which are common to all metazoa. In practical terms, this means that test which require 24-36 months to rear an aged rat for evaluation of a pharmaceutical, can potentially be accomplished in 21 days using the nematode. The paper emphasizes that the use of the C. elegans system as a primary screen for candidate compounds to intervene in the aging process can save time, effort and money, while ------------------- Key: 674 Medline: Authors: Johnson TE Title: C. elegans: A genetic model for understanding the aging process. Citation: "Intervention in the Aging Process, Part B." Regelson W and Sinex FM (eds), Alan R. Liss, NY. : 287-305 1983 Type: REVIEW Genes: Abstract: The long-term goal of our research is the understanding of the molecular processes that control metazoan aging. We present background material that describes the past difficulties in isolating long-lived mutants and present our results describing the isolation of such long-lived variants. Some of these variants have life spans more than 60% longer than wild types. We point out the genetic advantages of C. elegans which may have made the isolation of these variants possible. We also present indirect data suggesting that, at least for a subclass of these variants, the differences in mean lifespan are ascribable to factors other than those mediated by genetically induced caloric restriction. We discuss the possibility that these factors involve an alteration of what has been termed the "rate of aging". We also discuss the genetic approach to the understanding of senescence. ------------------- Key: 675 Medline: 84133307 Authors: Rand JB;Russell RL Title: Choline acetyltransferase-deficient mutants of the nematode C. elegans. Citation: Genetics 106: 227-248 1984 Type: ARTICLE Genes: ace-1 ace-2 cha-1 unc-17 unc-33 Abstract: We have identified five independent allelic mutations, defining the gene cha-1, that result in decreased choline acetyltransferase (ChAT) activity in Caenorhabditis elegans. Four of the mutant alleles, when homozygous, lead to ChAT reductions of greater than 98%, as well as recessive phenotypes of uncoordinated behavior, small size, slow growth and resistance to cholinesterase inhibitors. Animals homozygous for the fifth allele retain approximately 10% of the wild- type enzyme level; purified enzyme from this mutant has altered Km values for both choline and acetyl-CoA and is more thermolabile than the wild-type enzyme. These qualitative alterations, together with gene dosage data, argue that cha-1 is the structural gene for ChAT. cha-1 has been mapped to the left arm of linkage group IV and is within 0.02 map unit of the gene unc-17, mutant alleles of which lead to all of the phenotypes of cha-1 mutants except for the ChAT deficiency. Extensive complementation studies of cha-1 and unc-17 alleles reveal a complex complementation pattern, suggesting that both loci may be part of a single complex ------------------- Key: 676 Medline: Authors: Goldstein P Title: Triplo-X hermaphrodite of C. elegans: Pachytene karyotype analysis, synaptonemal complexes, and pairing mechanisms. Citation: Canadian Journal of Genetics & Cytology 26: 13-17 1984 Type: ARTICLE Genes: him-4 him-5 him-8 rad-4 mnT6 Abstract: Pairing of the three X chromosomes in the triplo-X strain of Caenorhabditis elegans occurs at pachytene in a two-by-two fashion such that one bivalent and one univalent are formed. The XX bivalent pairs synchronously with the autosomes and the univalent X remains in a similar chromatic state as the rest of the chromosomal complement. Normal tripartite synaptonemal complexes (SC) are formed between all bivalents. The univalent X lacks a SC and an axial core is not observed. The condensation of the univalent X in the triplo-X is different than in the male where the univalent X is heterochromatic. This real difference in condensation states of the chromatin may explain the fact that the univalent X is maintained in the male line yet is easily lost in the triplo-X strain. ------------------- Key: 677 Medline: Authors: Ouazana R;Herbage D;Godet J Title: Some biochemical aspects of the cuticle collagen of the nematode C. elegans. Citation: Comparative Biochemistry & Physiology 77B: 51-56 1984 Type: ARTICLE Genes: Abstract: 1. The collagenous proteins of the Caenorhabditis elegans cuticle exhibit different peptide maps when cleaved with Staphylococcus aureus V8 protease. 2. This result indicates that the cuticle proteins probably represent the products of a family of cuticle collagen genes, rather than the products of the post-translational modification of a small number of proteins. 3. Pepsin treatment of the cuticles solubilized only a low percentage of the proteins. 4. The pepsin resistant material shows an increased content of glycine compared with the purified cuticles and, when solubilized by reducing agents yields proteins of lower molecular weights than those released by non-pepsin-treated cuticles. 5. Reducible covalent cross-links derived from lysine are not present in C. elegans cuticle. ------------------- Key: 678 Medline: 84130170 Authors: Emmons SW;Yesner L Title: High-frequency excision of transposable element Tc1 in the nematode C. elegans is limited to somatic cells. Citation: Cell 36: 599-605 1984 Type: ARTICLE Genes: Abstract: Tc 1 transposable elements in the nematode Caenorhabditis elegans undergo excision at high frequency. We show here that this excision occurs primarily or entirely in the somatic tissues of the organism. Absence of germ-line excision is demonstrated by showing that Tc 1 elements are genetically stable; elements at particular genomic sites, as well as the overall number of elements in the genome, were stably maintained during a year of continuous, nonselective propagation. Somatic excision is demonstrated by showing that empty Tc 1 sites arise during a single generation of growth of a synchronous population and are not inherited by the next generation. These results suggest that excision of Tc 1 elements is under the control of tissue-specific factors. ------------------- Key: 679 Medline: 84191131 Authors: Klass MR;Kinsley S;Lopez LC Title: Isolation and characterization of a sperm-specific gene family in the nematode C. elegans. Citation: Molecular and Cellular Biology 4: 529-537 1984 Type: ARTICLE Genes: Abstract: The major sperm protein (MSP) of the nematode Caenorhabditis elegans is a low-molecular-weight (15,000) basic protein implicated in the pseudopodial movement of mature spermatozoa. Its synthesis occurs in a specific region of the gonad and is regulated at the level of transcription (M. Klass and D. Hirsh, Dev. Biol. 84:299-312, 1981; S. Ward and M. Klass, Dev. Biol. 92:203-208, 1982; Klass et al., Dev. Biol. 93:152-164, 1982). A developmentally regulated gene family has been identified that codes for this MSP. Whole genomic blots, as well as analysis of genomic clone banks, indicate that there are between 15 and 25 copies of the MSP gene in the nematode genome. Southern blot analysis also indicates that there is no rearrangement or amplification within the MSP gene family during development. No evidence was found of methylation at various restriction sites surrounding the MSP gene family, and similarly, no correlation between methylation and expression was observed. Three distinct members of this MSP gene family have been cloned, and their nucleotide sequences have been determined. Differential screening of a cDNA clone bank made from polyadenylated mRNA from adult males yielded 45 male-specific clones, 32 of which were clones of MSP genes. One of these cDNA clones was found to contain the entire nucleotide sequence for the MSP, including part of the 5' leader and all of the 3' trailing sequence. Genomic clones bearing copies of the MSP genes have been isolated. At least one of the members of this gene family is a pseudogene.(ABSTRACT TRUNCATED AT 250 ------------------- Key: 680 Medline: 84144794 Authors: Golden JW;Riddle DL Title: A pheromone-induced developmental switch in C. elegans: Temperature-sensitive mutants reveal a wild-type temperature-dependent process. Citation: Proceedings of the National Academy of Sciences USA 81: 819-823 1984 Type: ARTICLE Genes: daf-1 daf-2 daf-4 daf-7 daf-8 daf-11 daf-14 egl-4 egl-32 egl-40 sup-7 Abstract: Formation of a developmentally arrested dispersal stage called the dauer larva is enhanced by a Caenorhabditis-specific pheromone and is inhibited by increasing amounts of food. Pheromone-induced dauer larva formation of three tested wild-type strains is temperature- dependent, so that an increased percentage of the population forms dauer larvae at 25 degrees C compared to lower temperatures. Dauer- defective mutants fail to respond to added pheromone, and some behavioral mutants affected in thermotaxis or egg-laying also exhibit abnormal responses. Temperature-sensitive (ts) dauer-constitutive mutants form dauer larvae at a restrictive temperature regardless of environmental stimuli. At the permissive temperature (17.5 degrees C), alleles of six out of seven dauer-constitutive genes tested overrespond to the dauer-inducing pheromone. All known mutations in daf-4 (eight alleles) and daf-7 (five alleles) produce a ts dauer- constitutive phenotype. One daf-4 and one daf-7 allele are suppressed by the amber nonsense suppressor, sup-7(st5). At least these two dauer-constitutive mutations are likely to cause production of nonfunctional rather than ts gene products. These mutations appear to indirectly result in a ts phenotype by enhancing the expression of a wild-type ts developmental process. ------------------- Key: 681 Medline: Authors: Ohba K;Ishibashi N Title: A nematode, C. elegans, as a test organism for nematicide evaluation. Citation: Journal of Pesticide Science 9: 91-96 1984 Type: ARTICLE Genes: Abstract: Juveniles of Caenorhabditis elegans were transformed to dumpy in the media containing methomyl (10 ug/ml) or aldoxycarb (500 ug/ml), but not in the media containing methylisothiocyanate (MITC). The dumpy did not recover to its normal structure even after being transferred to fresh medium, but underwent to adulthood with a lower reproduction rate. The progeny from the dumpy forms was normal in structure, however, its reproductivity was as low as one-third of normal ones. Longevity of the dumpy form and its progeny were longer than those of normal worms. Methomyl (1 ug/ml), MITC (1 ug/ml) and aldoxycarb (10 ug/ml) did not suppress population growth, but MITC (10 ug/ml) did for the first two weeks. The population growth was markedly suppressed at 100 ug/ml of methomyl, 20 ug/ml of MITC and 1000 ug/ml of aldoxycarb. ------------------- Key: 682 Medline: Authors: Zuckerman BM;Kahane I Title: C. elegans: Stage specific differences in cuticle surface carbohydrates. Citation: Journal of Nematology 15: 535-538 1983 Type: ARTICLE Genes: Abstract: Stage-specific differences in wheat germ agglutinin (WGA) binding saccharides were demonstrated between the surfaces of eggs, L1 larvae, young adults, and old adults of Caenorhabditis elegans. The WGA binding was to n-acetylglucosamine groups but not to terminally linked n-acetylneuraminic acids. An age-related decrease in WGA binding occurred in adults, supporting previous findings of a decrease in net negative cuticle surface charge during aging. ------------------- Key: 683 Medline: Authors: Munakata N;Morohosh F Title: Effects of alkylating-agents on the nematode, C. elegans. Citation: Journal of Radiation Research 25: 31-31 1984 Type: ARTICLE Genes: Abstract: ------------------- Key: 684 Medline: 84188483 Authors: Blumenthal T;Squire M;Kirtland S;Cane J;Donegan M;Spieth J;Sharrock W Title: Cloning of a yolk protein gene family from C. elegans. Citation: Journal of Molecular Biology 174: 1-18 1984 Type: ARTICLE Genes: Abstract: We have cloned a family of five genes which encode the 170,000 Mr yolk proteins in the nematode Caenorhabditis elegans. The genes and their messenger RNAs are about 5 X 10(3) base-pairs in length. Thus most of the length of each gene is exon, although a few small introns have been discovered. Based on hybridization and restriction mapping experiments, the genes can be subdivided into two subfamilies: YP1- YP2 and YP3-YP4-YP5. Within a subfamily the genes are nearly identical. While most of the genes are not clustered, YP3 and YP4 are tandemly linked. Hybrid-arrest translation experiments demonstrate that the YP3-YP4-YP5 subfamily encodes the yp170A yolk protein, while the YP1-YP2 subfamily encodes the yp170B yolk protein. RNAs homologous to these genes are abundant in the adult hermaphrodite, but missing from larvae and males. Furthermore, RNA isolated from dissected intestines is highly enriched for sequences that hybridize to the genes, whereas RNA from gonad or body wall is nearly devoid of these sequences. Thus, this gene family is apparently expressed only in the intestine of the adult hermaphrodite. ------------------- Key: 685 Medline: Authors: Simpkin KG;Coles GC Title: The use of C. elegans for anthelmintic screening. Citation: Journal of Chemical Technology & Biotechnology 31: 66-69 1981 Type: ARTICLE Genes: Abstract: Caenorhabditis elegans maintained on ampicillin-treated Escherichia coli has been found to be sensitive to the benzimidazole anthelmintics, albendazole, cambendazole, fenbendazole, flubendazole, mebendazole, oxfendazole, oxibendazole, parbendazole, thiabendazole and the non-benzimidazoles, avermectin B1a, bitoscanate, febantel, levamisole, morantel, nitroscanate, oxantel, phenothiazine, pyrantel, pyrvinium pamoate, rafoxanide and stilbazium oxide at concentrations of 50 ug cm-3 or less. It can therefore be used in a high through-put in vitro pre-screen for anthelmintics. It is suggested that C. elegans may also be useful for evaluating the mode of action of drugs and the mechanism of resistance of nematodes to ------------------- Key: 686 Medline: 84159203 Authors: Golden JW;Riddle DL Title: The C. elegans dauer larva: Developmental effects of pheromone, food, and temperature. Citation: Developmental Biology 102: 368-378 1984 Type: ARTICLE Genes: daf-14 Abstract: Three environmental cues influence both the entry into and exit from the developmentally arrested dispersal stage called the dauer larva: a dauer-inducing pheromone, food, and temperature. The pheromone, which is a measure of population density, induces dauer larva formation at the second (L2) molt and inhibits recovery in a dose- dependent manner. Food acts competitively to reduce the frequency of dauer larva formation and to enhance recovery. The pheromone causes a specific extension of the second larval stage, coupled with a transient decrease in the growth rate of the L2. Second-stage larvae grown in the presence of added pheromone are morphologically distinguishable from L2 larvae grown without pheromone. We have named the pre-dauer L2 larva the L2d. Commitment to dauer larva formation can occur at the L2d molt. When L2d larvae are shifted out of pheromone to a lawn of E. coli just before the L2d molt, a few worms complete development into dauer larvae. In contrast, worms are essentially committed to the non-dauer life cycle by the first larval molt if the L1 larvae are not grown in appropriately high levels of pheromone. In the presence of pheromone, the percentage of dauer larva formation is enhanced at higher temperatures within the normal growth range. Temperature down-shifts induce dauer larva recovery. Temperature-shift experiments show that the enhancement of dauer larva formation requires exposure to the higher temperature around the L1 molt. Two sensory mutants defective in thermotaxis are altered in their sensitivity to the dauer-inducing pheromone, but their pheromone response retains temperature dependence. Response of dauer larvae to environmental cues is highly age dependent, with older dauer larvae exhibiting an increased tendency to recover. ------------------- Key: 687 Medline: 84232604 Authors: Gibert M-A;Starck J;Beguet B Title: Role of the gonad cytoplasmic core during oogenesis of the nematode C. elegans. Citation: Biology of the Cell 50: 77-85 1984 Type: ARTICLE Genes: Abstract: In order to elucidate the function of the cytoplasmic core (or rachis: a structure specific of the nematode gonads), we have carried out a cytological study of this structure in the free-living nematode Caenorhabditis elegans, in wild-type and in several mutant strains showing an abnormal gametogenesis. We also performed an ultrastructural radioautographic study of RNA synthesis during oogenesis in order to examine the part played by the rachis in the transport of nutritive substances. Our results evidence for the first time a metabolite transfer from the germ cells to the cytoplasmic core and lead us to assign to the core a trophic role linked to oogenesis. A statistical analysis of silver grain distribution has led us to conclude that there is no accumulation of RNA labelling in any part of the cytoplasmic core. In addition, our studies performed on sterile mutant strains suggest that the cytoplasmic core may have a specific function in oogenesis determination. ------------------- Key: 688 Medline: Authors: Chalfie M Title: Genetic analysis of nematode nerve-cell differentiation. Citation: Bioscience 34: 295-299 1984 Type: ARTICLE Genes: mec-1 mec-3 mec-4 mec-5 mec-7 unc-33 unc-86 Abstract: A small roundworm Caenorhabditis elegans has been the subject of extensive studies on the structure, function, and development of the nervous system. It is the only multicellular organism for which both the cellular anatomy (morphology and connectivity) and cell lineage origin for each of its 302 nerve cells are known. These data and the ability to obtain mutants that are defective in nerve-cell origin, structure, or function allow a detailed examination of the genetic control of nerve-cell production and differentiation. The use of touch-insensitive mutants to study the development of the six touch-receptor neurons of C. elegans is an example of such an analysis. ------------------- Key: 689 Medline: Authors: Denich KTR;Schierenberg E;Isnenghi E;Cassada R Title: Cell-lineage and developmental defects of temperature-sensitive embryonic arrest mutants of the nematode C. elegans. Citation: Roux's Archives of Developmental Biology 193: 164-179 1984 Type: ARTICLE Genes: emb-5 emb-6 emb-9 emb-13 emb-15 emb-16 emb-17 emb-18 emb-21 emb-22 emb-23 emb-24 emb-25 emb-26 emb-27 emb-28 emb-29 emb-30 emb-31 emb-32 emb-33 emb-34 emb-35 let-2 zyg-2 Abstract: The cellular phenotypes are described for 28 temperature-sensitive embryonic arrest mutants in 25 genes in the nematode Caenorhabditis elegans. Cell lineages, and cellular and subcellular properties at the non-permissive tmperature (26C) have been studied by direct observation of individual cells in living embryos using Nomarski microscopy and high-resolution video recordings. The sequence, direction and time of division and the position of the individual cells have been compared to wild-type development up to at least the 100-cell stage (or earlier stage of arrest). Defects are related to the previously reported arrest stage, temperature-sensitive period, and to maternal effects. Most maternal mutants display defects in zygote formation. These include absence of pronuclear fusion or of polar bodies, absence or abnormal position of pseudocleavage or of the first division cleavage, anomalous cytoplasmic streaming, eggshell defects, abnormal cytoplasmic yolk granules, extra (pro)nuclei, endomitosis or arrest at the one-cell stage. During embryogenesis, many mutants show cellular and/or morphological abnormalities, including pseudopodia, blastocoel malformation, prolonged mitosis and membrane reformation, ill-defined membranes, segregation of extra nuclei, and cytoplasmic "plaques" at division. Most mutants display defects in cell lineage features, i.e. slow cell division rate, abnormal division sequence or direction. Three mutants show premature germ-line cell division, one of these also having a supernumerary germ-line division. Nine mutants show defects in the intestinal cell lineage, i.e. in division direction, in timing relative to gastrulation or in intestine anatomy. This survey of the cellular properties of the mutants provides a basis for a more ------------------- Key: 690 Medline: 84188508 Authors: Sharrock WJ Title: Cleavage of two yolk proteins from a precursor in C. elegans. Citation: Journal of Molecular Biology 174: 419-431 1984 Type: ARTICLE Genes: Abstract: Four yolk proteins have been identified previously in the nematode Caenorhabditis elegans. However, only two of these proteins ( yp170A and yp170B ) are found among the products of in vitro translation of nematode RNA. The other two yolk proteins ( yp115 and yp88 ) are apparently cleaved from a precursor polypeptide of approximately 180,000 Mr. This precursor has been identified as an in vitro translation product and as a metabolically unstable polypeptide in vivo. It is bound by immunoglobulin G (IgG) specific for yp115 and by IgG specific for yp88 . The immunoadsorbed material yields the same pattern of fragments on partial digestion with Staphylococcus aureus V8 protease regardless of whether anti- yp115 or anti- yp88 IgG is used in the adsorption. Like the yp170 polypeptides, the yp115 / yp88 precursor is synthesized by the intestine and secreted intact. The precursor is evidently cleaved to yield yp115 and yp88 after secretion from the intestine but independent of the presence of the gonad. Thus, cleavage probably occurs in the body cavity of the nematode. ------------------- Key: 691 Medline: Authors: Brenner S Title: Nematode research. Citation: Trends in Biochemical Sciences 9: 172-172 1984 Type: REVIEW Genes: Abstract: For this 100th issue of TIBS, we were asked to look back at our subjects about eight years to when the journal first appeared and to discuss the important developments since that time. I found myself looking further back and I beg the reader's indulgence for some history that goes back some 21 years to the origins of our work on Caenorhabditis elegans. ------------------- Key: 692 Medline: Authors: Fodor A;Riddle DL;Nelson FK;Golden JW Title: Comparison of a new wild-type Caenorhabditis briggsae with laboratory strains of C. briggsae and C. elegans. Citation: Nematologica 29: 203-217 1983 Type: ARTICLE Genes: Abstract: The hermaphrodite nematode strain G16, isolated from soil in Gujarat, India was identified as Caenorhabditis briggsae by genetic and morphological criteria. By contrast with the Dougherty strain of C. briggsae, in culture since 1944, the behavior of G16 resembles that of the wild-type C. elegans N2. The Gujarat population does not exhibit uncoordinated movement, it produces males which mate efficiently, it exhibits chemotaxis, and it forms dauer larvae in response to crowding or starvation. The G16 animals grow bigger, have a shorter generation time (1.6 days at 25C) and produce larger broods than the Dougherty strain. We conclude that the Dougherty strain has accumulated genetic defects during the years of laboratory cultivation. Genetic analysis using G16-Dougherty hybrids demonstrates that the defects in movements, chemotaxis, and dauer larva formation are all X-linked but genetically separable, while morphological differences in the male copulatory bursa are inherited autosomally. A Caenorhabditis-specific pheromone, which enhances entry into the dauer larva stage, is produced by the N2, G16, and Dougherty strains, but the Dougherty strain does not respond to the pheromone. The new wild-type C. briggsae may be more appropriate than the Dougherty strain for genetic study of C. briggsae or for future comparative ------------------- Key: 693 Medline: 84206965 Authors: Goldstein P Title: Sterile mutants in C. elegans: The synaptonemal complex as an indicator of the stage-specific effect of the mutation. Citation: Cytobios 39: 101-108 1984 Type: ARTICLE Genes: Abstract: Two sterile mutants of Caenorhabditis elegans hermaphrodites have been examined using the electron microscope and serial section analysis. The F4 and F80 mutants were described previously ( Mounier and Brun , 1980), and they were shown to be blocked at the start of oogenesis. In the F4 mutant, normal sperm are produced and the pachytene nuclei contain tripartite synaptonemal complexes (SC) between the homologously paired chromosomes. In the F80 asynaptic mutant, only a few sperm are produced and they have abnormal morphology. Whereas SCs and SC associated structures (termed 'SC knobs') are present in the F4, these structures are absent from the F80 . The mutation in F80 affects gametogenesis prior to the pachytene stage of meiosis and pairing of homologous chromosomes apparently does not occur. The SC knobs may influence the regulation of the disjunction of the chromosomes. For that reason, these structures are now ------------------- Key: 694 Medline: Authors: Yosida TH;Sadaie T;Sadaie Y Title: Somatic and meiotic chromosomes of the small free-living nematode, C. elegans. Citation: Proceedings of the Japan Academy 60B: 54-57 1984 Type: ARTICLE Genes: Abstract: The small free-living nematode, Caenorhabditis elegans, has recently been widely utilized as an attractive organism in molecular biology, since the genetic analysis was carried out by Brenner. In the adult hermaphrodites, only about 800 somatic cells are included in one individual and their cell lineage can easily be recognized in the body. The haploid DNA of this worm was known to be only 20 times as large as that of the genome of the Enterobacteriaceae, Escherichia coli, and also know to have six linkage groups. The meiotic chromosomes stained by the Feulgen method of this nematode have been reported by Nigon and Brun. According to them the haploid number was six in accordance with six linkage groups by genetic analysis. The work of karyotype analysis in this worm by light microscope has not attracted cytogeneticists, because the somatic chromosomes had been shown to be very tiny. Electron microscopic analysis seemed to be necessary for analysis of the somatic chromosomes in this worm as carried out by Goldstein et al and Goldstein. However, the technique for observation of somatic chromosomes in small worms has rapidly developed. By use of this technique we succeeded to observe the chromosomes of the small free-living nematode, C. elegans. In the present paper, the chromosomes of this worm in early embryonic stage of hermaphrodites will be described with special attention to their figures of the somatic and ------------------- Key: 695 Medline: 84255548 Authors: McLachlan AD Title: Structural implications of the myosin amino acid sequence. Citation: Annual Review of Biophysics & Bioengineering 13: 167-189 1984 Type: REVIEW Genes: unc-54 Abstract: Many questions about the action of muscle would be answered if we knew the atomic structures of both myosin and actin. The analysis of complete myosin genes and the sequencing of amino acids are vital steps towards this end. Genetic analysis identifies the different variants of myosin that exist in each animal, and the study of mutants will help to distinguish essential parts of the molecule. New cloned genes with changed functions will soon be constructed. The amino acid sequence places the important active groups and structural units of this very large protein in their correct framework. It also helps to show how the individual molecules form into regular arrays in the thick filaments of muscle. Under the electron miscroscope, individual myosin molecules appear to have long, thin rodlike tails with two globular heads emerging in a forked configuration at one end. Each molecule is a doublet containing two, paired myosin chains. The rod part is approximately 1500 A long and 20 A in diameter, while the heads are elongated, with a diameter of 70 A and length of up to 200 A. The main protein subunit of myosin is called the heavy chain. The unc-54 gene heavy chain from the soil nematode worm Caenorhabditis elegans contains 1966 amino acids (Figures 1 and 2). Figure 1 also shows part of M. Elzinga's chemical sequence from the head of rabbit skeletal muscle for comparison. The rod sequence from nematode alone contains 7-residue and 28-residue repeats, so it is laid out in zones of 28 amino acids with its own local numbering system (1' to 1117') indicated in the rest of this article by primes. Other sequences and special features marked in the Figures are described later. This review concentrates on structural aspects of muscle, excluding chemical kinetics and the dynamics of contraction. We begin with a short account of basic facts. Next we consider the myosin genes and the topography of the active regions in the head. An analysis of regularities in the rod sequence then leads on to questions about thick filaments packing and the mechanical flexibility of the ------------------- Key: 696 Medline: 84261408 Authors: Albertson DG Title: Localization of the ribosomal genes in C. elegans chromosomes by in situ hybridization using biotin-labeled probes. Citation: EMBO Journal 3: 1227-1234 1984 Type: ARTICLE Genes: eDf3 mnT2 sDp1 eDp20 mnT11 mnT12 mnDp10 mnDp11 mnDp35 Abstract: The site of the ribosomal gene cluster on embryonic metaphase chromosomes of Caenorhabditis elegans has been mapped by in situ hybridization using probe DNAs that have been nick-translated to incorporate biotin-labeled UTP. The hybridized probe DNA was detected by a double-layer fluorescent antibody technique. Since chromosomes from wild-type C. elegans embryos are indistinguishable, in situ hybridization was carried out with chromosomes from C. elegans strains carrying cytologically distinct translocation or duplication chromosomes in order to identify the right end of linkage group I as the site of the ribosomal genes. Chromosomes carrying a lethal mutation, let-209 I displayed smaller hybridization signals than wild- type, suggesting that these chromosomes carried a partial deficiency of the ribosomal gene cluster. A duplication of the ribosomal genes, eDp20(I;II) rescued let-209 homozygotes. Chromosomes carrying the alterations in the ribosomal genes were combined with mnT12(IV;X) to facilitate the mapping of genes in C. elegans by in situ hybridization. Linkage groups I and II are then labeled by the distinctive hybridization signals from the ribosomal probes, linkage groups IV and X are together distinguishable morphologically and linkage group V is labeled by hybridization to a 5S gene probe. ------------------- Key: 697 Medline: 84273027 Authors: Fujita H;Ishii N;Suzuki K Title: Effects of 8-methoxypsoralen plus near-ultraviolet light on the nematode C. elegans. Citation: Photochemistry and Photobiology 39: 831-834 1984 Type: ARTICLE Genes: Abstract: Effects of 8-methoxypsoralen plus near-UV light on the nematode Caenorhabditis elegans were studied as a novel example of photosensitized actions at the individual level. Either the eggs or the worms were illuminated with near-UV light in the presence of 8-methoxypsoralen. The treatment decreased hatchability of the eggs depending on light fluence and concentration of the sensitizer. Inhibition of growth and premature death were observed when the larvae in the second stage were illuminated in the presence of 8-methoxypsoralen. When young adults were treated before the beginning of egg-laying, they grew to lay eggs, but the total number of eggs deposited per hermaphrodite was decreased and the life span was shortened. ------------------- Key: 698 Medline: 84223963 Authors: Marx JL Title: C. elegans: Getting to know you. Citation: Science 225: 40-42 1984 Type: REVIEW Genes: lin-12 Abstract: The end of 1983 saw the completion of a major project in developmental biology. All the cell divisions, deaths, and migrations that generate the embryonic, then the larval, and finally the adult forms of the roundworm Caenorhabditis elegans have now been traced. It is the first time the complete cell lineage of an organism of this degree of complexity, one that contains many of the diverse cell types found in all higher animals, has been determined. ------------------- Key: 699 Medline: 85035857 Authors: Rose AM;Baillie DL;Curran J Title: Meiotic pairing behavior of two free duplications of linkage group I in C. elegans. Citation: Molecular & General Genetics 195: 52-56 1984 Type: ARTICLE Genes: sDp1 sDp2 Abstract: In this paper we describe the meiotic pairing behavior of two free duplications in Caenorhabditis elegans. sDp1 is a duplication of approximately 30 map units of the right portion of linkage group I including unc-74 to unc-54. This duplication pairs, recombines, and apparently segregates from one of the normal homologues. A second duplication, sDp2, is a duplication of approximately 15 map units of the left portion of the linkage group. sDp2 was not observed to recombine with the normal homologue but did suppress exchange between the two normal homologues in a sDp2/ ++/ dpy-5 unc-35 heterozygote. Although a number of free duplications have been described previously in Caenorhabditis elegans, none of these have been shown to pair with normal homologues. The meiotic behavior of the duplications described in this paper can be understood assuming the existence in C. elegans chromosomes of pairing sites of the type described in D. melanogaster chromosomes (I. Sandler 1956; Hawley 1980). ------------------- Key: 700 Medline: 85035846 Authors: Snutch TP;Baillie DL Title: A high degree of DNA strain polymorphism associated with the major heat shock gene in C. elegans. Citation: Molecular & General Genetics 195: 329-335 1984 Type: ARTICLE Genes: Abstract: We have searched for sequence variation between the Bristol and Bergerac strains of C. elegans in regions flanking three members of the 70 kilodalton (kd) heat shock peptide (hsp) gene family. No sequence variation was detected in 40 kb of DNA flanking two 70 kd hsp genes which are not stimulated by heat shock. In contrast, analysis of DNA flanking the heat shock inducible 70 kd hsp gene showed an unusually high amount of sequence variation between the two strains. Isolation and restriction map analysis of this gene from both strains revealed that the 5' and 3' flanking regions have diverged by 8.1 and 7.0% in nucleotide sequence, respectively. We have shown that these alterations are not due to large DNA rearrangements and conclude that the majority of sequence difference is the result of point mutations. Our results suggest that the heat shock inducible 70 kd hsp gene region accumulates mutations at a rate 10 to 20 fold higher than other regions of the genome. We propose that the anomalously high accumulation of mutational events is a direct consequence of the special status of the 70 kd hsp gene and its surrounding chromatin domain in the germline of C. elegans. ------------------- Key: 701 Medline: Authors: Strome S;Wood WB Title: Segregation of germ-line-specific antigens during embryogenesis in C. elegans. Citation: "Molecular Aspects of Early Development." Malacinski GM and Klein WH (eds), Plenum Press. : 141-165 1984 Type: REVIEW Genes: emb-27 fer-1 ixs-1 ixs-2 zyg-9 zyg-11 Abstract: Germ cells in a wide variety of invertebrate and vertebrate species contain distinctive cytoplasmic organelles that have been visualized by electron microscopy. The ubiliquity of such structures suggests that they play some role in germ-line determination or differentiation, or both. However, the nature and function of these structures remain unknown. We describe experiments with two types of immunologic probes, rabbit sera and mouse monoclonal antibodies, directed against ctyoplamsic granules that are unique to germ-line cells in the nematode, Caenorhabditis elegans, and that may correspond to the germ-line-specific structures seen by electron microscopy in C. elegans embryos. The antibodies have been used to follow the granules, termed P granules, during early embryonic cleavage stages and throughout larval and adult development. P granules become progressively localized to the germ-line precursor cells during early embryogenesis. We are using conditionally lethal maternal-effect mutations to study this localization process. In addition to providing a rapid assay for P granules in wild-type, mutant, and experimentally maipulated embryos, the antibodies also promise to be useful in biochemically characterizing the granules and in investigating their ------------------- Key: 702 Medline: 84206592 Authors: White JG;Southgate E;Thomson JN;Brenner S Title: Factors that determine connectivity in the nervous system of C. elegans. Citation: Cold Spring Harbor Symposia on Quantitative Biology 48: 633-640 1983 Type: REVIEW Genes: Abstract: The nervous system of C. elegans is arranged as a collection of process bundles. Processes within bundles are generally unbranched and occupy defined positions relative to their neighbors. Small groups of processes are often closely associated together and run adjacent to one another for relatively long distances. We have defined the set of neurons that have processes adjacent to the processes of a given neuron as the neighborhood of that neuron. Synapses in C. elegans are made en passant between adjacent processes. Of the 1165 pairs of adjacent processes that were analyzed, 520 (45%) had synaptic contacts. The set of neurons that make synaptic contact with a given neuron is therefore, on average, 45% of that neuron's neighborhood. Neurons make synaptic contacts with fewer classes of partners than they have the potential for, as they are limited in their choice of partner to those that inhabit their neighborhood. Some classes of neurons have processes that make abrupt transitions from one neighborhood to another. There is usually some identifiable cue at the transition point, such as the termination of a closely associated process or a discontinuity at the junction of one process bundle with another. Neurons that inhabit more than one neighborhood have a more extended set of synaptic partners than those that are confined to a single ------------------- Key: 703 Medline: 84248050 Authors: Ruan K-S;Emmons SW Title: Extrachromosomal copies of transposon Tc1 in the nematode C. elegans. Citation: Proceedings of the National Academy of Sciences USA 81: 4018-4022 1984 Type: ARTICLE Genes: Abstract: Extrachromosomal copies of the 1.6-kilobase transposable element Tc1 are present at the level of between 0.1 and 1.0 copy per cell in Caenorhabditis elegans strain Bergerac. Extrachromosomal elements were detected and studied using Southern hybridizations employing a Tc1-specific probe. The amount of extrachromosomal Tc1 DNA was roughly constant during development in Bergerac, which has approximately 300 integrated chromosomal copies of Tc1 in its haploid genome. Extrachromosomal Tc1 DNA was not detected in strain Bristol, which has 30 chromosomal copies of Tc1. Three forms of extrachromosomal DNA were detected. The predominant form was a 1.6- kilobase linear molecule with ends corresponding to the ends of an integrated Tc1 element. The other two forms were, respectively, relaxed and supercoiled circular copies of the element. Structural assignments were based on electrophoretic mobility, the results of sedimentation velocity and equilibrium density gradient experiments, and on the sizes of the products produced by treatment of purified extrachromosomal DNA with restriction endonucleases. The suggestion is made that these extrachromosomal transposable elements are the products of excision events known to be occurring at high frequency in somatic cells in Bergerac. ------------------- Key: 704 Medline: 84223935 Authors: Lewin R Title: Why is development so illogical? Citation: Science 224: 1327-1329 1984 Type: NEWS Genes: Abstract: "People thought I was crazy," recalls Sydney Brenner, director of the Medical Research Council's Laboratory of Molecular Biology, Cambridge, England. "Jim Watson said he wouldn't give me a penny to do it. He said I was 20 years ahead of my time." But, with the help of a group of extremely dedicated and inventive associates, Brenner is well on the way with his crazy project. He has transformed the tiny nematode Caenorhabditis elegans into a subject of serious science: more is know about the genetics and development of this 1-millimeter roundworm than about any other multicellular creature. ------------------- Key: 705 Medline: 84223981 Authors: Lewin R Title: The continuing tale of a small worm. Citation: Science 225: 153-156 1984 Type: NEWS Genes: Abstract: "We have a complete description of the whole nervous system in terms of all the neurons and the connections they make." This simple statement, by John White of the Medical Research Council's Laboratory of Molecular Biology, Cambridge, England, sums up a brilliantly conceived and doggedly implemented research effort of more than a decade's duration on the 1-mm-long nematode Caenorhabditis elegans. White is currently contemplating the eventual publication of what amounts to a detailed atlas of this modest worm's nervous system, an opus that threatens to exceed the capacity of even the most accommodating journal. A 500-page monograph is the likely compromise. ------------------- Key: 706 Medline: 84291270 Authors: Nelson FK;Riddle DL Title: Functional study of the C. elegans secretory-excretory system using laser microsurgery. Citation: Journal of Experimental Zoology 231: 45-56 1984 Type: ARTICLE Genes: daf-7 unc-32 Abstract: Individual cells of the Caenorhabditis elegans secretory-excretory system were ablated by laser microbeam in various larval stages. Effects on growth, molting, osmoregulation, fertility, longevity, and dauer larva formation were tested. Single-cell ablations did not prevent subsequent molting, but ablation of the pore cell or the duct cell resulted in the absence of the normal cuticular lining of the excretory duct following a molt. When the pore cell, duct cell, or excretory cell was ablated, the animals filled with fluid within 12- 24 hr and died within a few days, producing very few progeny. Ablation of the excretory gland cell, on the other hand, had no obvious developmental or behavioral effects. Excretory activity was monitored in dauer larvae by observing pulsation of the excretory duct in conditions of differing osmolarity. The rate of pulsation was quite variable over time in conditions of low osmotic strength, but average five- to six-fold higher than that observed in buffered saline. These observations, combined with the effects of laser ablation, lead to the conclusion that one ------------------- Key: 707 Medline: 84259343 Authors: Politz JC;Edgar RS Title: Overlapping stage-specific sets of numerous small collagenous polypeptides are translated in vitro from C. elegans RNA. Citation: Cell 37: 853-860 1984 Type: ARTICLE Genes: Abstract: Caenorhabditis elegans synthesizes four morphologically distinct types of collagenous cuticles during its lifetime. We show that in RNA populations isolated early or late during the L4-to-adult molt, chick and nematode collagen DNAs hybridize strongly to RNAs of about 1.2 kb. Different but overlapping classes of correspondingly small collagenous polypeptides (310-460 residues in length) are translated in vitro from these two populations and from RNA isolated at the L2- to-dauer molt. Over 60 different collagenous translation products are identified. These collagenous polypeptides are smaller than mature cuticle collagens and smaller than most vertebrate collagens. They probably represent cuticle collagen precursors and the primary products of the cuticle collagen genes of C. ------------------- Key: 708 Medline: Authors: Chalfie M Title: Neuronal development in C. elegans. Citation: Trends in Neurosciences 7: 197-202 1984 Type: REVIEW Genes: lin-12 mab-5 mec-1 mec-3 mec-4 mec-5 mec-7 mec-12 unc-33 Abstract: Research on the nematode Caenorhabditis elegans has provided a description of the development and structure of a nervous system at an exceptional level of detail. Both the synaptic connectivity and the cell lineage origin of all of the 302 neurons of the adult hermaphrodite are known. This description serves as the background for studies into the genetic control of neuronal development. Numerous mutations have been isolated that affect the production, differentiation, structure and function of the C. elegans neurons. ------------------- Key: 710 Medline: 84272657 Authors: Anderson P;Brenner S Title: A selection for myosin heavy-chain mutants in the nematode C. elegans. Citation: Proceedings of the National Academy of Sciences USA 81: 4470-4474 1984 Type: ARTICLE Genes: let-49 let-50 let-201 let-202 let-203 let-204 let-205 let-206 let-207 let-208 lev-10 lev-11 unc-54 unc-59 unc-75 eDf3 eDf4 eDf5 eDf6 eDf7 eDf9 eDf10 eDf11 eDf12 eDf13 eDf14 eDf15 eDf16 Abstract: The unc-54 gene of Caenorhabditis elegans encodes an abundant myosin heavy chain protein expressed in body-wall muscle cells. We have designed genetic techniques that select directly for unc-54 mutants. This selection is based upon properties of the unc-54 dominant allele e1152. Mutations that eliminate dominance of e1152 are null alleles of unc-54. Deletions have been identified by their genetic properties. We have defined mutationally a number of essential genes near unc-54, and we have described the genetic fine structure of this region of linkage group I. As much as 27% of the unc-54 mutations induced by the bifunctional alkylating agent 1,2,7,8-diepoxyoctane are multisite deletions. Extrachromosomal free duplications that include unc-54 are also described. ------------------- Key: 711 Medline: Authors: Golden JW;Riddle DL Title: A C. elegans dauer-inducing pheromone and an antagonistic component of the food supply. Citation: Journal of Chemical Ecology 10: 1265-1280 1984 Type: ARTICLE Genes: Abstract: The free-living soil nematode Caenorhabditis elegans forms a nonfeeding dispersal stage at the second molt called the dauer larva when exposed to environmental cues indicating crowding and limited food. An improved bioassay, tenfold more sensitive than that used previously, has been used in the characterization of the two chemical cues which act competitively in controlling this developmental process. The pheromone concentration provides a measure of the population density; it enhances dauer larva formation, and inhibits recovery (exit) from the dauer stage. The pheromone is a family of related molecules which are nonvolative, very stable, and possess physical and chromatographic properties similar to those of hydroxylated fatty acids and bile acids. A food signal, with effects on development opposite those of the pheromone, is produced by bacteria, and is also present in yeast extract. In contrast to the pheromone, the food signal is a labile substance which is neutral and hydrophilic. ------------------- Key: 712 Medline: 85004704 Authors: Herman RK Title: Analysis of genetic mosaics of the nematode C. elegans. Citation: Genetics 108: 165-180 1984 Type: ARTICLE Genes: daf-6 flu-3 osm-1 sup-10 unc-3 unc-93 mnDp1 mnDp2 mnDp3 mnDf41 mnDf42 mnDf43 mnDp12 mnDp14 Abstract: A new method for producing genetic mosaics, which involves the spontaneous somatic loss of free chromosome fragments, is demonstrated. Four genes that affect the behavior of C. elegans were studied in mosaic animals. The analysis is known. Two of the mutant genes affect certain sensory responses and prevent uptake of fluorescein isothiocyanate (FITC) by certain sensory neurons. Mosaic analysis indicated that one of these mutant genes is cell autonomous with respect to its effect on FITC uptake and the other is cell nonautonomous. In the latter case, the genotype of a non-neuronal supporting cell that surrounds the processes of the neurons that normally take up FITC probably is critical. The other two mutant genes affect animal movement. Mosaic analysis indicated that the expression of one of these genes is specific to certain neurons (motor neurons of the ventral and dorsal nerve cords are prime candidates and the expression of the other gene is specific ------------------- Key: 713 Medline: Authors: Starck J Title: Synthesis of oogenesis specific proteins in C. elegans: An approach to the study of vitellogenesis in a nematode. Citation: International Journal of Invert. Repro. & Develop. 7: 149-160 1984 Type: ARTICLE Genes: zyg-1 zyg-2 zyg-3 Abstract: In vivo labeled proteins from the nematode Caenorhabditis elegans were analyzed by SDS-polyacrylamide gel electrophoresis and fluorography. The study was performed in the wild-type strain during development and in several mutants displaying altered gametogenesis or altered embryogenesis. The patterns observed during the last larval stage and the beginning of the adult stage show that the synthesis of the 4 adult-hermaphrodite specific proteins described by Klass is tightly correlated to the onset of oogenesis. This synthesis takes place mainly in the intestine and, to a lesser extent, in the two gonadal arms. This synthesis is also observed in all the mutants studied including those which produce no diakinetic growing oocytes. Furthermore, in mutants, a difference in the labeling intensity of the 4 adult-hermaphrodite specific proteins was observed in relation to the ability to lay eggs. These results suggest that these proteins are yolk proteins. Possible interaction between the control of oogenesis and the control of yolk protein synthesis is ------------------- Key: 714 Medline: 84286385 Authors: Kimble J;Edgar L;Hirsh D Title: Specification of male development in C. elegans: The fem genes. Citation: Developmental Biology 105: 234-239 1984 Type: ARTICLE Genes: fem-1 fem-2 him-8 tra-1 Abstract: Mutation of the gene fem-2 causes feminization of both sexes: hermaphrodites make no sperm, and males produce oocytes in an intersexual somatic gonad. A double mutant harboring ts alleles of both fem-1 (formerly named isx-1; G. A. Nelson, K. K. Lew, and S. Ward, 1978, Dev. Biol. 66, 386-409) and fem-2 causes transformation of XO animals (normally male) into spermless hermaphrodites at restrictive temperature. The phenotypes, temperature-sensitive periods, and maternal effects observed in mutants of each fem gene are found to be similar. It is suggested that the fem genes are centrally involved in specification of male development in Caenorhabditis elegans--both in the germ line of hermaphrodites and in somatic and germ line tissues of ------------------- Key: 715 Medline: 85052462 Authors: Sigurdson DC;Spanier GJ;Herman RK Title: Caenorhabditis elegans deficiency mapping. Citation: Genetics 108: 331-345 1984 Type: ARTICLE Genes: bli-1 dpy-2 dpy-10 emb-27 let-19 let-22 let-23 let-24 let-25 let-26 let-27 let-28 let-29 let-30 let-31 let-236 let-237 let-238 let-239 let-240 let-241 let-242 let-243 let-244 let-245 let-246 let-247 let-248 let-249 let-250 let-251 let-252 let-253 let-254 let-255 let-256 let-257 let-258 let-259 let-260 let-261 let-262 let-263 let-264 let-265 let-266 let-267 let-268 let-269 let-270 let-271 lin-5 lin-29 ooc-1 ooc-2 ooc-3 rol-1 rol-6 spe-1 spe-2 spe-3 sqt-1 tra-2 unc-4 unc-15 unc-104 unc-105 vab-9 zyg-11 mnC1 mnDf12 mnDf14 mnDf16 mnDf22 mnDf24 mnDf25 mnDf26 mnDf27 mnDf28 mnDf29 mnDf30 mnDf31 mnDf32 mnDf33 mnDf35 mnDf36 mnDf37 mnDf38 mnDf39 mnDf40 mnDf44 mnDf45 mnDf46 mnDf47 mnDf48 mnDf49 mnDf50 mnDf51 mnDf52 mnDf53 mnDf54 mnDf55 mnDf56 mnDf57 mnDf58 mnDf59 mnDf60 mnDf61 mnDf62 mnDf63 mnDf64 mnDf65 mnDf66 mnDf67 mnDf68 mnDf69 mnDf70 mnDf71 mnDf73 mnDf74 mnDf75 mnDf76 mnDf77 mnDf78 mnDf80 mnDf81 mnDf83 mnDf84 mnDf85 mnDf86 mnDf87 mnDf88 mnDf89 mnDf90 mnDf91 mnDf92 mnDf93 mnDf94 mnDf95 mnDf96 mnDf97 mnDf98 mnDf99 mnDf100 mnDf101 mnDf103 mnDf104 mnDf105 Abstract: Six schemes were used to identify 80 independent recessive lethal deficiencies of linkage group (LG) II following X-ray treatment of the nematode Caenorhabditis elegans. Complementation tests between the deficiencies and ethyl methanesulfonate-induced recessive visible, lethal and sterile mutations and between different deficiencies were used to characterize the extents of the deficiencies. Deficiency endpoints thus helped to order 36 sites within a region representing about half of the loci on LG II and extending over about 5 map units. New mutations occurring in this region can be assigned to particular segments of the map by complementation tests against a small number of deficiencies; this facilitates the assignment of single-site mutations to particular genes, as we illustrate. Five sperm-defective and five oocyte- defective LG II sterile mutants were identified and mapped. Certain deficiency-by-deficiency complementation tests allowed us to suggest that the phenotypes of null mutations at two loci represented by visible alleles are wild type and that null mutations at a third locus confer a visible phenotype. A segment of LG II that is about 12 map units long and largely devoid of identified loci seems to be greatly favored for crossing over. ------------------- Key: 716 Medline: Authors: Vanfleteren JR Title: Nematodes as nutritional models. Citation: "Nematodes as Biological Models, Volume 2: Aging and Other Model Systems." Zuckerman BM (ed), Academic Press, NY. 2: 47-79 1980 Type: REVIEW Genes: Abstract: The use of nematodes as model organisms for the study of metazoan organization assumes a detailed knowledge of all facets of their biology. This chapter covers the nutritional aspects of the nematode model as revealed by studies on Caenorhabditis briggsae and Caenorhabditis elegans and a few other nematode species that have been established in axenic culture. The term axenic, which means "free of other organisms" was proposed by Dougherty (1960) in preference to other terms such as "sterile", "aseptic", and "pure" that would be rather ambiguous in this respect. Since most of the nematodes under discussion are bacteria feeders and some of them fungal-feeding species, it is essential that axenic culture conditions are rigidly maintained when studying nematode requirements. This chapter appraises the present state of nematode nutrition, and refers particularly to those nematodes that are currently used as model organisms for basic research of behavior, development, and aging. Detailed information on the culture methods and specific diets of these and other nematodes in axenic culture may be found in a previous review. ------------------- Key: 717 Medline: 84041508 Authors: Rosenzweig B;Liao LW;Hirsh D Title: Target sequences for the C. elegans transposable element Tc1. Citation: Nucleic Acids Research 11: 7137-7140 1983 Type: ARTICLE Genes: Abstract: The target sequences for two independent insertions of the transposable element Tc1 from Caenorhabditis elegans show homology. Because both insertions are at palindromic TA/AT sequences, the exact boundaries of Tc1 cannot be distinguished; Tc1 could be 1610 bp and flanked by a 2-bp duplication of the target site or it could be 1612 bp and without target site duplication. The latter possibility implies a novel manner for insertion of a transposable element. ------------------- Key: 718 Medline: Authors: Seymour MK;Wright KA;Doncaster CC Title: The action of the anterior feeding apparatus of C. elegans (Nematoda: Rhabditida). Citation: Journal of Zoological Society of London 201: 527-539 1983 Type: ARTICLE Genes: Abstract: From the analysis of cine film, combined with ultrastructural observations, the anterior feeding structures and their behaviour in the free-living microbivorous nematode Caenorhabditis elegans during ingestion in dense and sparse suspensions of Escherichia coli are described. In dense suspensions bacteria accumulate in the buccal cavity against the three metastomal flaps that nearly close it, and are then swallowed down the three tubular apical expansions of the triradiate oesophageal lumen when the flaps open. Excess medium is then expelled, as the oesophageal lumen closes and traps the swallowed bacteria. The flaps and oesophagus operate by contractions in the seven most anterior oesophageal muscle cells, probably coordinated via proprioceptive nerve endings between the cells. About one million nematode hours are needed to extract 1 g of bacteria from 30 ml of medium. With few or no bacteria, the head moves more, the metastomal flaps do not close and the medium seems to pass in and out of the buccal cavity, probably as part of the widespread exploration phase of food-finding behaviour. Abnormal feeding behaviour, control and functions of the metastomal flaps and associated structures, and control of food intake volume ------------------- Key: 719 Medline: Authors: Ward S Title: Genetic analysis of the sensory nervous system of C. elegans. Citation: Proc. Fifth International Congress on Parasitology 2: 28-31 1982 Type: REVIEW Genes: mec-1 mec-3 mec-7 mec-13 unc-86 Abstract: During the past ten years the nematode Caenorhabditis elegans has been subjected to intensive anatomical, genetic, developmental and behavioral analysis. More than 2500 mutants have been isolated; the complete developmental lineages of all embryonic and post embryonic cells have been determined; and the complete wiring diagram of its 300 neurons has been reconstructed by serial electron microscopy. Although C. elegans is a nonparasitic bacteria eating soil nematode and thus is not a proper subject for a parasitology congress, so much has been learned about this worm that it was elevated to honorary parasite status for this meeting. I will review some examples of how the genetic analysis of this helminth has helped established the function of parts of the sensory nervous system. Since the neuroanatomy of nematodes is so highly conserved these results should apply to parasitic nematodes as well. ------------------- Key: 720 Medline: 85012704 Authors: Rose AM;Snutch TP Title: Isolation of the closed circular form of the transposable element Tc1 in C. elegans. Citation: Nature 311: 485-486 1984 Type: ARTICLE Genes: Abstract: The mobilization of Tc1, a transposable element in the genome of the roundworm Caenorhabditis elegans, has been investigated. Genomic blot hybridization has shown that Tc1 exists in very different numbers in the genomes of two closely related strains of C. elegans: there are -30 copies of Tc1 in the Bristol, whereas in the Bergerac strain there are 200-300. Most of these Tc1 elements are structurally highly conserved although there exists a second form which contains a HindIII restriction site (Tc1 (Hin) form) and comprises -10% of the population. Excision of Tc1 from its chromosomal location in the Bergerac strain is indicated by the presence, on genomic blots, of a minor bind corresponding to the size of the uninserted restriction fragment. Here we describe the recovery of extrachromosomal linear and closed circular copies of Tc1 from the Bergerac strain, presumably a result of Tc1 ------------------- Key: 721 Medline: 85030654 Authors: Roberts TM;Streitmatter G Title: Membrane-substrate contact under the spermatozoon of C. elegans, a crawling cell that lacks filamentous actin. Citation: Journal of Cell Science 69: 117-126 1984 Type: ARTICLE Genes: Abstract: Caenorhabditis elegans spermatozoa use a single, persistent pseudopod to crawl at about 20 micrometers/min but, unlike other types of crawling cells, sperm lack both filamentous actin and myosin. Interference reflection microscopy has revealed that sperm form broad grey areas of contact, analogous to the close contacts that have been described underneath other crawling eukaryotic cells, between their pseudopods and their substrate. Individual sperm change the size, shape and pattern of their substrate attachments as they crawl but we found no correlation between the extent of underside of the cell in contact with the substrate and the velocity of locomotion. Two predominant attachment patterns were observed: (1) a single broad contact extending from the front of the pseudopod nearly to the rear of the cell; and (2) two separate contact sites, one under the front of the pseudopod and one under the cell body. Occasionally, under cells exhibiting the second type of attachment pattern, portions of the anterior contact separated and remained stationary relative to the substrate while the cell moved forward. This observation, as well as the continuous change in shape of the contact areas, suggests that sperm continually form new contacts near the tip of the pseudopod and release these contacts backwards. In extreme cases, sperm were able to crawl with only the front of the pseudopod in contact with the substrate. Therefore, we propose that sperm locomotion depends on the interaction of several key events (traction, propulsion, membrane insertion) occurring at the leading edge of the ------------------- Key: 722 Medline: 85085944 Authors: Cox GN;Kramer JM;Hirsh D Title: Number and organization of collagen genes in C. elegans. Citation: Molecular and Cellular Biology 4: 2389-2395 1984 Type: ARTICLE Genes: col-1 col-2 col-12 col-13 col-16 col-18 col-20 daf-2 Abstract: We analyzed the number and organization of collagen genes in the nematode Caenorhabditis elegans. Genomic Southern blot hybridization experiments and recombinant phage library screenings indicated that C. elegans has between 40 and 150 distinct collagen genes. A large number of recombinant phages containing collagen genes were isolated from C. elegans DNA libraries. Physical mapping studies indicated that most phage contained a single small collagen gene less than 3 kilobases in size. A few phage contained multiple collagen hybridizing regions and may contain a larger collagen gene or several tightly linked small collagen genes. No overlaps were observed between phages containing different collagen genes, implying that the genes are dispersed in the C. elegans genome. Consistent with the small size of most collagen genes, we found that the predominant class of collagen mRNA in C. elegans is 1.2 to 1.4 kilobases in length. Genomic Southern blot experiments under stringent hybridization conditions revealed considerable sequence diversity among collagen genes. Our data suggest that most collagen genes are unique or are present in only a few copies. ------------------- Key: 723 Medline: 85050105 Authors: Lozano R;Chitwood DJ;Lusby WR;Thompson MJ;Svoboda JA;Patterson GW Title: Comparative effects of growth-inhibitors on sterol-metabolism in the nematode C. elegans. Citation: Comparative Biochemistry & Physiology 79C: 21-26 1984 Type: ARTICLE Genes: Abstract: An analogous series of dimethylalkyl compounds, consisting of four amines, an amide, and a phosphonate ester, inhibited motility and reproduction of the nematode Caenorhabditis elegans. Dimethylamines with straight-chain lengths of 12, 14, or 16 carbon atoms were equally active nematicides, causing greater than 80% population growth inhibition at a concentration of 25 ppm. The C12 straight- chain amine and its corresponding amide produced similar inhibition and were much more potent than either the corresponding C12 phosphonate or a C12 branched-chain amine. Inhibition of the delta 24- sterol reductase system was exhibited by all four amines, but not by the amide or phosphonate, in the following order of activity: C12 branched-chain amine greater than C12 straight-chain amine greater than C14 amine greater than C16 amine. The C12 branched amine also blocked the C-24(28)-dehydrogenase system in the conversion of sitosterol to fucosterol, the initial step in sitosterol dealkylation. ------------------- Key: 724 Medline: 85028044 Authors: Doniach T;Hodgkin J Title: A sex-determining gene, fem-1, required for both male and hermaphrodite development in C. elegans. Citation: Developmental Biology 106: 223-235 1984 Type: ARTICLE Genes: dpy-21 dpy-26 fem-1 him-8 mor-2 sup-7 tra-1 tra-2 tra-3 unc-7 Abstract: Sex in the nematode Caenorhabditis elegans is normally determined by the X chromosome to autosome (X:A) ratio, with XX hermaphrodites and XO males. Previous work has shown that a set of at least four autosomal genes (her-1, tra-2, tra-3, and tra-1) is signaled by the X:A ratio and appears to act in a regulatory pathway to determine sex. Twenty-one new recessive alleles of the gene fem-1(IV) (formerly isx-1) have been isolated. Seven of these may be null alleles; one of these is an amber mutation. The other 14 alleles are temperature sensitive. The putative null mutations cause both XO and XX animals to develop as females when the mother as well as the zygote is fem-1(- ). Therefore, fem-1(+) is required (a) for the development of the male body and (b) for spermatogenesis in males and hermaphrodites. In addition, fem-1 shows a maternal effect: wild-type fem-1 product partially rescues the development of fem-1(-) progeny. By analyzing double mutants it has been shown that fem-1(+) is part of the sex- determination pathway and has two distinct functions: (1) in the soma it prevents the action of tra-1, thereby allowing male development to occur, and (2) in the germline it is necessary for spermatogenesis in both sexes. ------------------- Key: 725 Medline: Authors: Lu NC;Cheng AC;Briggs GM Title: A study of mineral requirements in C. elegans. Citation: Nematologica 29: 425-434 1983 Type: ARTICLE Genes: Abstract: The quantities of Mg+2, Na+, K+, Mn+2, Ca+2 and Cu+2 required by the free-living nematode C. elegans were determined. An individual mineral deficieny was developed by deleting the mineral from the basal medium. Quantitative requirements of individual minerals were determined respectively by adding each mineral at various concentrations to the depleted medium. Serial subcultures and biological pre-treated media were used for the development of Mn+2, Ca+2 and Cu+2 deficiencies. It was found that most C. elegans were supported at 73 ug/ml Mg+2, 300 ug/ml Na+, 530 Ug/ml K+, 6.3 ug/ml Mn+2, 1500 ug/ml Ca+2 and 7.2 ug/ml Cu+2. ------------------- Key: 726 Medline: 85036460 Authors: Hartman PS Title: Effects of age and liquid holding on the UV-radiation sensitivities of wild-type and mutant C. elegans dauer larvae. Citation: Mutation Research 132: 95-99 1984 Type: ARTICLE Genes: rad-1 rad-2 rad-3 rad-7 Abstract: The dauer larva is a facultative developmental stage in the life cycle of the nematode Caenorhabditis elegans. Dauer larvae, which can survive under starvation for over 60 days, resume normal development when feeding is resumed. Wild-type (N2) and 4 radiation-sensitive (rad) mutant dauer larvae were tested for their abilities to develop into adults after UV-irradiation. The rad-3 mutant was over 30 times as sensitive as N2; rad-1, rad-2 and rad-7 mutants were not hypersensitive. Irradiation also delayed development in survivors. Wild-type dauer larvae did not differ in radiation sensitivity from 0 through 50 days of age. There was no liquid holding recovery (LHR); that is, survival did not increase when wild-type dauer larvae were held in buffer after irradiation. ------------------- Key: 727 Medline: 85077577 Authors: Moerman DG;Waterston RH Title: Spontaneous unstable unc-22 IV mutations in C. elegans var. Bergerac. Citation: Genetics 108: 859-877 1984 Type: ARTICLE Genes: unc-22 Abstract: This paper describes a mutator system in the nematode Caenorhabditis elegans var. Bergerac for the gene unc-22. Of nine C. elegans and two C. briggsae strains tested only the Bergerac BO strain yielded mutant animals at a high frequency and the unc-22 IV gene is a preferred mutational target. The forward spontaneous mutation frequency at the unc-22 locus in Bergerac BO is about 1 X 10(-4), and most of these spontaneous unc-22 mutations revert at frequencies between 2 X 10(-3) and 2 X 10(-4). Both the forward mutation frequency and the reversion frequency are sensitive to genetic background. Spontaneous unc-22 mutations derived in a Bergerac background and placed in a primarily Bristol background revert at frequencies of less than 10(-6). When reintroduced into a Bergerac/Bristol hybrid background the mutations once again become unstable. The mutator activity could not be localized to a discrete site in the Bergerac genome. Nor did mutator activity require the Bergerac unc-22 gene as a target since the Bristol unc-22 homolog placed in a Bergerac background also showed high mutation frequency. Intragenic mapping of two spontaneous unc-22 alleles, st136 and st137, place both mutations in the central region of the known unc-22 map. However, these mutations probably recombine with one another, suggesting that the unstable mutations can occur in more than one site in unc-22. Examination of the phenotypic effect of these mutations on muscle structure indicates that they are less severe in their effect than a known amber allele. We suggest that this mutator system is polygenic and dispersed over the nematode genome and could represent activity of the transposable element Tc1. ------------------- Key: 728 Medline: 85051729 Authors: Jansson H-B;Jeyaprakash A;Damon RA;Zuckerman BM Title: C. elegans and Panagrellus redivivus: Enzyme-mediated modification of chemotaxis. Citation: Experimental Parasitology 58: 270-277 1984 Type: ARTICLE Genes: che-3 daf-6 Abstract: Treatment with mannosidase or sialidase completely inhibited chemotactic responses of Caenorhabditis elegans wild type, C. elegans mutants CB1377 (daf-6)X and CB1379 (che-3)I, and Panagrellus redivivus to a source of attractants. Trypsin (EC3.4.21.4) caused a partial reduction in the level of chemoresponse. Normal chemotaxis was renewed within 20 hr following exposure to the enzymes. Other enzymes tested had no effect. Experimental and supporting evidence is presented that behavioral modification resulted from functional impairments to receptors located within chemosensory sensilla. ------------------- Key: 729 Medline: 85038599 Authors: Bolten SL;Powell-Abel P;Fischhoff DA;Waterston RH Title: The sup-7(st5) X gene of C. elegans encodes a transfer RNA-Trp-UAG amber suppressor. Citation: Proceedings of the National Academy of Sciences USA 81: 6784-6788 1984 Type: ARTICLE Genes: sup-5 sup-7 stDf1 Abstract: In earlier studies, we identified in Caenorhabditis elegans two informational suppressors sup-5 III and sup-7 X and recently showed that these suppressors acted via an altered tRNA to suppress translational termination at amber (UAG) stop codons. We now show that the sup-7 (st5) suppressor is a tRNATrpUAG amber suppressor. These studies utilized a radiolabeled purified tRNA fraction to identify hybridizing genomic sequences in a phage genomic library. DNA sequence analysis of the hybridizing segment of one clone showed that the probe recognized a tRNATrpUGG sequence. The sup-7 gene was shown to be one of an 11 or 12 member tRNATrp family by Southern blot analysis, taking advantage of an Xba I restriction site induced in the anticodon sequence by the mutational event to suppressor. Sequence analysis of a recombinant lambda clone containing sup-7 gene proved that sup-7(st5) is a tRNATrpUAG. This conclusive proof of the nature of sup7(st5) will permit unambiguous interpretation in genetic applications, and the availability of the cloned sequences may allow the sup-7 gene to be used to select for the reintroduction of DNA into C. elegans. ------------------- Key: 730 Medline: 85054957 Authors: Yarbrough PO;Hecht RM Title: Two isoenzymes of glyceraldehyde-3-phosphate dehydrogenase in C. elegans. Isolation, properties, and immunochemical characterization. Citation: Journal of Biological Chemistry 259: 14711-14720 1984 Type: ARTICLE Genes: Abstract: Two glyceraldehyde-3-phosphate dehydrogenases have been separated and purified from the nematode Caenorhabditis elegans. As defined by starch gel electrophoresis, the faster-migrating isoenzyme, glyceraldehyde-3-phosphate dehydrogenase-2, increases its activity during postembryonic development. In contrast, the slower-migrating isoenzyme, glyceraldehyde-3-phosphate dehydrogenase-1, is enriched in isolated embryos. Both isoenzymes were initially purified by ammonium sulfate fractionation, gel filtration, and NAD+-agarose affinity chromatography. The separation of both isoenzymes as well as their purification to homogeneity was obtained by preparative chromatofocusing. The subunit molecular weight of each isoenzyme is 38,500 +/- 500. A tetrameric native molecular weight of 157,000 +/- 2000 was determined for glyceraldehyde-3-phosphate dehydrogenase-2. Monospecific rabbit polyclonal antibodies were initially raised against the major isoenzyme and subsequently used to characterize both isoenzymes. Staphylococcus aureas V8 protease digests of each isoenzyme were separated electrophoretically and stained immunochemically, providing evidence that the two isoenzymes differed in their amino acid sequences. Developmental immunocytochemical studies suggest that the embryonic-enriched isoenzyme, glyceraldehyde- 3-phosphate dehydrogenase-1, is present in all cells. The second isoenzyme, exhibiting the major activity during postembryonic larval development, may define a body-wall-muscle specific activity which is located within the actin-containing I and A zones of the nematode's ------------------- Key: 731 Medline: 85147624 Authors: Sternberg PW;Horvitz HR Title: The genetic control of cell lineage during nematode development. Citation: Annual Review of Genetics 18: 489-524 1984 Type: ARTICLE Genes: ced-3 ced-4 her-1 lin-12 lin-14 lin-17 lin-22 tra-1 unc-86 Abstract: As recognized by T. H. Morgan, the problems of genetics and development are interwoven: understanding how the genotype of an organism specifies its phenotype requires knowing the fundamental mechanism of gene action, how genes interact to specify the properties of cells, and how cells interact to specify each adult character. We now know that the primary effect of a gene is to encode a protein or RNA product. However, little is known about how the genes of a zygote specify a complex pattern of cell divisions, the generation of diverse cell types, and the arrangement of those cells into specific morphological structures. A "favorable material" (as Morgan put it) for investigating these problems would be a simple organism in which development could be analyzed at the level of single genes and single cells. The small free-living soil nematode Caenorhabditis elegans is such an organism. C. elegans is easily grown and handled in the laboratory and is well suited for both genetic and developmental studies. This nematode consists of only about 1,000 (non-germ) cells, and both its anatomy and its development are essentially invariant. The complete anatomy of C. elegans, including the "wiring diagram" of the nervous system, is known at an ultrastructural level. In addition, the developmental origin of every cell is known since the complete cell lineage from the zygote to the adult has been determined. The genetic properties of C. elegans allow researchers to combine the classical Mendelian approach of Morgan and his coworkers with the approach of modern microbial genetics: C. elegans is diploid but microscopic in size (so large numbers of animals can be handled, up to 10*5 on a single petri dish) and has a very rapid life cycle (an egg matures into a fertile adult within two to four days, depending upon temperature; this adult produces 300-400 progeny over the next few days, resulting in an effective organismal doubling time of about 15 hours). Many aspects of the biology of C. elegans have been reviewed. Here we describe how these features have led to an initial understanding of some of the issues concerning genetics and development that Morgan raised fifty years ago. We review the methods underlying and the results derived form four approaches that have been used to study the genetics of nematode development. The first approach, which takes advantage of the genetic diversity generated by evolution, is to compare the development of related species. For example, simple differences in otherwise identical cell lineages may be the result of one or a few mutational events that occurred during the divergence of two species; the nature of these differences can suggest ways in which genes may control development. The second approach is to identify a large set of mutations that affect particular cell lineages; this approach can indicate the number, types, and specificities of genes that affect particular developmental events. The third approach involves the detailed genetic analyses of genes identified by mutations that alter development; such studies can reveal the wild-type functions of those genes and thereby identify genes that play regulatory roles in development. The fourth approach is to examine the interactions among mutations using studies of extragenic suppression and epistasis; this type of analysis can suggest how genes interact during normal development to ------------------- Key: 732 Medline: 85102733 Authors: Eide D;Anderson P Title: The gene structures of spontaneous mutations affecting a C. elegans myosin heavy chain gene. Citation: Genetics 109: 67-79 1985 Type: ARTICLE Genes: unc-54 unc-105 Abstract: We have isolated spontaneous mutations affecting the unc-54 major myosin heavy chain gene of Caenorhabditis elegans (variety Bristol). Spontaneous unc-54 mutants occur in C. elegans populations at a frequency of approximately 3 X 10(-7). We have studied the gene structure of 65 independent unc-54 mutations using filter-transfer hybridization techniques. Most unc-54 mutations (50 of 65) exhibit no abnormalities detected with these techniques; these mutations are small lesions affecting less than 100 base pairs. Approximately 17% of the mutations (11 of 65) are simple deletions, ranging in size from less than 100 base pairs to greater than 17 kilobases. One isolate contains two separate deletions, each of which affects unc- 54. Two mutants contain tandem genetic duplications that include a portion of unc-54 and extend 8-10 kilobases beyond the 5' terminus of the mRNA. Conspicuously absent from our collection of spontaneous unc- 54 mutations are any resulting from insertion of transposable genetic elements. Such mutants, if they occur, must arise at a frequency of less than 5 X 10(-9). ------------------- Key: 733 Medline: 85102734 Authors: Hartman PS Title: Epistatic interactions of radiation-sensitive (rad) mutants of C. elegans. Citation: Genetics 109: 81-93 1985 Type: ARTICLE Genes: rad-1 rad-2 rad-3 rad-7 Abstract: Six double mutants and a quadruple mutant were derived from four UV radiation-hypersensitive single mutants (rad-1, rad-2, rad-3 and rad- 7). Sensitivities of the 11 strains to UV, gamma-radiation and methyl methanesulfonate (MMS) were compared. Of the six double mutants, only the rad-1;rad-2 and rad-3;rad-7 doubles were no more hypersensitive than the most sensitive single mutant to UV-radiation. Thus, rad-1 and rad-2 define one epistasis group, whereas rad-3 and rad-7 define another. Consistent with this model was the observation that rad-1 and rad-2, but not rad-3 and rad-7, were hypersensitive to gamma- radiation. In addition, none of the multiple mutants was more hypersensitive to gamma-radiation than the most sensitive single rad mutant. No synergistic interactions of the rad mutations with respect to MMS sensitivities were ------------------- Key: 734 Medline: 84173237 Authors: Chitwood DJ;Lusby WR;Lozano R;Thompson MJ;Svoboda JA Title: Novel nuclear methylation of sterols by the nematode C. elegans. Citation: Steroids 42: 311-319 1983 Type: ARTICLE Genes: Abstract: Caenorhabditis elegans possesses a unique sterol methylation pathway not reported to occur in any other organism and also removes the C-24 ethyl group of sitosterol (a plant sterol). This nematode produced substantial quantities of 4 alpha-methyl-5 alpha-cholest-8(14)-en-3 beta-ol and smaller amounts of lophenol from dietary cholesterol, desmosterol or sitosterol. When C. elegans was propagated in media containing sitosterol plus 25-azacoprostane hydrochloride (25-aza-5 beta-cholestane hydrochloride), an inhibitor of delta 24-sterol reductase in insects, its 4 alpha-methylsterol fraction largely consisted of equal amounts of 4 alpha-methyl-5 alpha-cholesta-7,24- dien-3 beta-ol and 4 alpha-methyl-5 alpha-cholesta-8(14),24-dien-3 beta-ol. Thus 25-azacoprostane hydrochloride inhibited both a delta 24-sterol reductase and a delta 7-sterol isomerase ------------------- Key: 735 Medline: 85056972 Authors: Rand JB;Russell RL Title: Properties and partial purification of choline acetyltransferase from the nematode C. elegans. Citation: Journal of Neurochemistry 44: 189-200 1985 Type: ARTICLE Genes: Abstract: We have stabilized and studied choline acetyltransferase from the nematode Caenorhabditis elegans. The enzyme is soluble, and two discrete forms were resolved by gel filtration. The larger of these two forms (MW approximately 154,000) was somewhat unstable and in the presence of 0.5 M NaI was converted to a form indistinguishable from the "native" small form (MW approximately 71,000). We have purified the small form of the enzyme greater than 3,300-fold by a combination of gel filtration, ion-exchange chromatography, and nucleotide affinity chromatography. The purified preparation has a measured specific activity of 3.74 mumol/min/mg protein, and is free of acetylcholinesterase and acetyl-CoA hydrolase activities. The Vmax of the purified enzyme is stimulated by NaCl, with half-maximal stimulation at 80 mM NaCl. The Km for each substrate is also affected by salt, but in different manners from each other and the Vmax; the kinetic parameter Vmax/Km thus changes significantly as a function of the salt concentration. ------------------- Key: 736 Medline: 85084899 Authors: Johnson TE;Mitchell DH;Kline S;Kemal R;Foy J Title: Arresting development arrests aging in the nematode C. elegans. Citation: Mechanisms of Ageing & Development 28: 23-40 1984 Type: ARTICLE Genes: Abstract: Larval development of the nematode, Caenorhabditis elegans, can be arrested by either of two different treatment: (1) complete starvation, or (2) growth in a partially defined culture medium (axenic medium) of strains adapted to bacterial growth. The developmental arrest is complete under total starvation and the starved populations live about 10 days. The developmental block is incomplete in axenic medium; most animals mature but maturation takes 10 times longer than normal. If developmentally arrested cultures are returned to growth on E. coli, both the completely starved and the axenically arrested cultures mature at normal rates. Life-span is prolonged by 1 day for each day of complete starvation; life-span is prolonged by 0.7 days for each day of axenic arrest. These results suggest that aging and development are closely coupled in this system. The results are discussed in terms of previous observations on nutritional deprivation in other invertebrates and caloric restriction in mammals and are interpreted in light of theoretical models of senescence. ------------------- Key: 737 Medline: Authors: Marx JL Title: New clues to developmental timing. Citation: Science 226: 425-426 1984 Type: REVIEW Genes: lin-14 lin-28 lin-29 Abstract: Within the past few years researchers have finally begun to be able to peer inside a hitherto impenetrable black box, namely, the development of complex organisms. The genes that control the commitment of embryonic cells to specific fates are now being found and characterized. A case in point is reported in this issue of Science (p. 409). Victor Ambros of Harvard University and H. Robert Horvitz of Massachusetts Institute of Technology have identified genes that affect the timing of developmental events in the roundworm Caenorhabditis elegans. ------------------- Key: 738 Medline: 85163460 Authors: Eide DJ;Anderson P Title: Novel insertion mutation in C. elegans. Citation: Molecular and Cellular Biology 5: 1-6 1985 Type: ARTICLE Genes: unc-54 Abstract: The mutation e1662 is an allele of the Caenorhabditis elegans unc-54 gene induced with the difunctional alkylating agent 1,2,7,8- diepoxyoctane. unc-54 encodes the major myosin heavy chain isozyme of body wall muscle cells. Filter-transfer hybridization and DNA sequence analysis show that e1662 is an insertion of 288 base pairs of DNA within unc-54. The inserted DNA is identical to a 288-base pair region of unc-54 located ca. 600 base pairs from the insertion site. Thus, e1662 is a displaced duplication. A 14-base pair sequence located at one end of the duplicated segment is found adjacent to the site of insertion. These homologous sequences are juxtaposed head-to- tail by the insertion event. e1662 thus contains a tandem direct repeat extending across one of its junctions. ------------------- Key: 739 Medline: 85086059 Authors: Goldstein P Title: The synaptonemal complexes of C. elegans--Pachytene karyotype analysis of the rad-4 radiation-sensitive mutant. Citation: Mutation Research 129: 337-343 1984 Type: ARTICLE Genes: him-4 him-5 him-8 rad-4 mnT6 Abstract: In the rad-4 mutant of C. elegans there is a specific increase in the number of 'Disjunction Regulator Regions' (DDR) present on the synaptonemal complexes (SC) in pachytene nuclei. These DRRs either promote disjunction or inhibit nondisjunction of the X-chromosome as evidenced by the 10-fold decrease in the rate of X-chromosome nondisjunction as compared to the wild-type. The structure of the tripartite SC is normal, thus, the decrease in the rate of X- chromosome nondisjunction in the rad-4 mutant is not related to the structure of the SC but may be related to the number of DRRs. Other changes are also associated with the sensitivity to irradiation, i.e. the pachytene nuclear morphology is altered such that nuclei and nucleoli are 50% the size of wild-type. In addition, the autosomal: X- chromosome size ratio is reduced in the rad-4 mutant. That there are six SCs confirms n = 6 in this mutant and of these six SCs three can be identified: (1) the XX bivalent, SC No. 1, is the shortest and pairs synchronously with the autosomes; (2) the longest bivalent, SC No. 6, carries the nucleolar organizer region at one extreme end; and (3) SC No. 5 has two DRRs located approximately one micron apart from each other. ------------------- Key: 740 Medline: 85077225 Authors: Hedgecock EM;White JG Title: Polyploid tissues in the nematode C. elegans. Citation: Developmental Biology 107: 128-133 1985 Type: ARTICLE Genes: lin-5 Abstract: During larval development, the number of somatic nuclei in C. elegans hermaphrodites increases from 558 to 959 (J. E. Sulston and H. R. Horvitz, Dev. Biol. 56, 110-156, 1977; J. E. Sulston et al., Dev. Biol. 100, 64-119, 1983). At the same time, the animals increase about 60-fold in volume. We have measured the DNA contents of several classes of nuclei by quantitating the fluorescence of Hoescht 33258 stained DNA (D. G. Albertson et al., Dev. Biol. 63, 165-178, 1978). Probably all embryonic nuclei, including those of neurons, muscles, hypodermis, and intestine, are diploid at hatching. Neurons, muscles, and nondividing hypodermal nuclei remain diploid throughout larval development. The DNA content of the intestinal nuclei doubles at the end of each larval stage, reaching 32C by the adult stage. New hypodermal cells, generated by division of seam cells in the larval stages, undergo an additional round of DNA replication before fusing with the major syncytium (hyp7, Sulston et al., 1983). Thus the larval hyp7 syncytium comprises a fixed number of diploid embryonic nuclei plus an increasing number of tetraploid postembryonic nuclei. Some of the endoreduplications that occur in the intestinal and hypodermal lineages of C. elegans may correspond to nuclear or cellular divisions in another nematode Panagrellus redivivus (P. W. Sternberg and H. R. Horvitz, Dev. Biol. 93, 181-205, 1982). ------------------- Key: 741 Medline: 85134867 Authors: Waterston RH;Hirsh D;Lane TR Title: Dominant mutations affecting muscle structure in C. elegans that map near the actin gene cluster. Citation: Journal of Molecular Biology 180: 473-496 1984 Type: ARTICLE Genes: act-1 act-2 act-3 sup-3 eDf1 mDf1 Abstract: By examining F1 progeny of mutagenized Caenorhabditis elegans larvae, we recovered several dominant mutations which affect muscle structure. Five of these new mutations resulted in phenotypes unlike the previously recognized unc-54 and unc-15 dominant alleles. Mapping studies placed all five mutations in the same small region of linkage group V. Polarized light, fluorescence and electron microscopic studies showed that a prominent feature of the disorganized myofilament lattice is the abnormal placement of thin filaments within the body wall muscle cells. Pharyngeal musculature is also affected by three of the mutations when homozygous. Of the five mutations only three are homozygous viable. All three of these have unusually high intragenic reversion rates either spontaneoulsy (10*-6) or after ethyl methanesulfonate mutagenesis (2x10*-5), suggesting that reversion occurs through loss of function mutations. No unlinked suppressor mutations were found. The dominance of the mutations, the effect on thin filaments and the reversion properties suggested that these new dominant mutations lie in a gene or genes specifying a structural component of the thin filament. The positioning of a set of three actin sequences in the same region led us to speculate that these ------------------- Key: 742 Medline: 85134868 Authors: Landel CP;Krause M;Waterston RH;Hirsh D Title: DNA rearrangements of the actin gene-cluster in C. elegans accompany reversion of 3 muscle mutants. Citation: Journal of Molecular Biology 180: 497-513 1984 Type: ARTICLE Genes: act-1 act-2 act-3 Abstract: We present evidence that associates dominant mutations in Caenorhabditis elegans that disrupt muscle structure and motility with a cluster of three actin genes mapped in the same region of linkage group V. We examined spontaneous and mutagen-induced wild-type revertants of these dominant alleles for alterations in the DNA of the actin gene cluster. Four of 73 revertants contain detectable DNA rearrangements within the cluster of actin genes including an insertion, a deletion and gene fusions. We postulate that these rearrangements inactivate or delete at least one gene in the cluster and consequently the original mutations are within the actin gene cluster. ------------------- Key: 743 Medline: 84123650 Authors: Neigauz BM;Ravin VK Title: The effect of physiologically active substances on life duration of a nematode C. elegans. Citation: Zhurnal Obshchei Biologii 44: 835-841 1983 Type: ARTICLE Genes: Abstract: ------------------- Key: 744 Medline: 85080119 Authors: Strehler EE;Mahdavi V;Periasamy M;Nadal-Ginard B Title: Intron positions are conserved in the 5' end region of myosin heavy-chain genes. Citation: Journal of Biological Chemistry 260: 468-471 1985 Type: ARTICLE Genes: unc-54 Abstract: We have determined the 5' end sequence of the rat embryonic skeletal muscle myosin heavy-chain (MHC) gene comprising the first three amino-terminal coding exons. Comparison with the corresponding regions of the rat ventricular a and the nematode Caenorhabditis elegans unc-54 MHC genes shows that the degree of amino acid sequence conservation increases from the first to the third exon. Intron positions between these exons are maintained in all three genes studied, whereas size and sequence of corresponding introns are highly divergent. In contrast to the rat MHC genes where the coding region is highly split throughout its entire length, only the 5' end region is frequently interrupted by introns in the nematode gene indicating the potential importance of these introns in gene structure and expression. The occurrence of "preferential" intron positions in the MHC genes suggests the existence of a highly split ancestral MHC from which different evolutionary lineages removed and/or added specific sets of ------------------- Key: 745 Medline: 85127928 Authors: Schierenberg E;Wood WB Title: Control of cell-cycle timing in early embryos of C. Citation: Developmental Biology 107: 337-354 1985 Type: ARTICLE Genes: Abstract: A technique has been developed for extruding either substantial amounts of cytoplasm without nuclei or individual nuclei with small amounts of cytoplasm from early embryos of C. elegans after perforating the eggshell with a laser microbeam. This technique, in conjunction with laser-induced cell fusion, has allowed the altering of nuclear/cytoplasmic ratios and the exposing of the nucleus of one cell to cytoplasm from another. Using these approaches the roles of nuclei and cytoplasm in determining the different cell-cycle periods of the several blastomere lineages in early embryos have been examined. It was found that nuclei in a common cytoplasm divide synchronously; enucleated blastomeres retain a cycling period characteristic of their lineage; cycling period is not substantially affected by changes in the ratio of nuclear to cytoplasmic volumes or the DNA content per cell; the period of a cell from one lineage can be substantially altered by introduction of cytoplasm from a cell of another lineage with a different period; and short-term effects of foreign cytoplasm on the timing of the subsequent mitosis differ depending on position of the donor cell in the cell cycle. These results are discussed in connection with models for the action of cytoplasmic factors in controlling cell-cycle timing. ------------------- Key: 746 Medline: 85105075 Authors: Kramer JM;Cox GN;Hirsh D Title: Expression of the C. elegans collagen genes col-1 and col-2 is developmentally regulated. Citation: Journal of Biological Chemistry 260: 1945-1951 1985 Type: ARTICLE Genes: col-1 col-2 Abstract: The total collagen gene expression as well as the specific expression of two sequenced Caenorhabditis elegans collagen genes, col-1 and col- 2, has been investigated. Northern blots of RNA isolated from animals at different developmental stages were probed under conditions that allow cross-hybridization of all collagen sequences. The majority of hybridization is to transcripts of 1.1-1.4 kilobases (kb) in length, with weak hybridization to some larger transcripts. Different size patterns, within the 1.1-1.4-kb ranges, are seen in RNAs from different developmental stages. Gene-specific probes were produced from the C. elegans collagen genes col-1 and col-2, and each was shown to hybridize to a single size transcript in the 1.1-1.4-kb region. The col-1 transcript was found in all the developmental stages examined, but its abundance varied between stages. The col-2 transcript was detected only in a single developmental stage, during formation of the dauer larvae. The 5' and the 3' ends of the col-1 and col-2 transcripts were determined by S1 nuclease digestion experiments. Both genes have the common "TATA" and "CAAT" box sequences preceding the 5' end of their transcripts and there is strong sequence homology in their 5' untranslated regions. Multiple copies of an eight-nucleotide repeat sequence were found upstream from both col-1 and col-2. ------------------- Key: 747 Medline: 85140249 Authors: Chandra HS Title: Sex determination: A hypothesis based on noncoding DNA. Citation: Proceedings of the National Academy of Sciences USA 82: 1165-1169 1985 Type: ARTICLE Genes: dpy-26 her-2 tra-1 Abstract: Certain recent models of sex determination in mammals, Drosphila melanogaster, Caenorhabditis elegans, and snakes are examined in the light of the hypothesis that the relevant genetic regulatory mechanisms are similar and interrelated. The proposed key element in each of these instances is a noncoding DNA sequence, which serves as a high-affinity binding site for a repressor-like molecule regulating the activity of a major "sex-determining" gene. On this basis it is argued that, in several eukaryotes, (i) certain DNA sequences that are sex-determining are noncoding, in the sense that they are not the structural genes of a sex-determining protein; (ii) in some species these noncoding sequences are present in one sex and absent in the other, while in others their copy number or accessibility to regulatory molecules is significantly unequal between the two sexes; and (iii) this inequality determines whether the embryo develops into a male or a female. ------------------- Key: 748 Medline: 85137502 Authors: Cox GN;Hirsh D Title: Stage-specific patterns of collagen gene-expression during development of C. elegans. Citation: Molecular and Cellular Biology 5: 363-372 1985 Type: ARTICLE Genes: col-1 col-2 col-3 col-6 col-7 col-8 col-10 col-11 col-12 col-13 col-14 col-15 col-16 col-17 col-18 col-19 Abstract: Collagens are the major protein components of the Caenorhabditis elegans cuticle and are encoded by a large family of 40 to 150 closely related but nonidentical genes. We have determined temporal patterns of mRNA accumulation for a large number of collagen genes by screening recombinant phages and plasmids containing cloned collagen genes under high stringency conditions with 32P-labeled cDNA preparations specific for eggs or three postembryonic molts. We find that collagen mRNA levels are regulated both temporally and quantitatively during C. elegans development. Most genes studied exhibit one of four patterns of mRNA accumulation which correlate with changes in cuticle morphology and collagen protein composition during development. Our results suggest that, in general, there is a progressive activation of new collagen genes during normal development. ------------------- Key: 749 Medline: Authors: Kenyon CJ Title: Heterochronic mutations of C. elegans--their developmental and evolutionary significance. Citation: Trends in Genetics 1: 2-2 1985 Type: REVIEW Genes: lin-14 lin-28 lin-29 Abstract: V. Ambros and R. Horvitz have identified a set of genes that may control the timing of developmental events in the nematode Caenorhabditis elegans. After hatching, C. elegans proceeds to the adult stage via four juvenile stages, each followed by a molt. Each juvenile stage is characterized by a distinct pattern of cell division and differentiation called an S1, S2, S3 or S4 lineage pattern. Ambros and Horvitz have found that the S1-S4 lineage patterns are modular; that is, a lineage pattern (including hypodermal, neuronal, muscle, and intestinal divisions and differentiations) characteristic of one stage can be expressed at a different stage. Each behaves as a complex lineage cassete that can be inserted into one or more of the available temporal slots. ------------------- Key: 750 Medline: 85155449 Authors: Rosenbluth RE;Cuddeford C;Baillie DL Title: Mutagenesis in Caenorhabditis elegans. II. A spectrum of mutational events induced with 1500 R of gamma-radiation. Citation: Genetics 109: 493-511 1985 Type: ARTICLE Genes: let-326 let-327 let-329 let-331 rol-3 unc-46 unc-62 eT1 sT1 sT2 sT3 sT4 sDp3 sDp4 sDf20 sDf26 sDf27 sDf28 sDf29 sDf30 Abstract: We previously established a gamma-ray dose-response curve for recessive lethal events (lethals) captured over the eT1 balancer. In this paper we analyze the nature of lethal events produced, with a frequency of 0.04 per eT1 region, at a dose of 1500 r. To do so, we developed a protocol that, in the absence of cytogenetics, allows balanced lethals to be analyzed for associated chromosomal rearrangements. A set of 35 lethal strains was chosen for the analysis. Although the dosage was relatively low, a large number of multiple-break events were observed. The fraction of lethals associated with rearrangements was found to be 0.76. Currently most X- and gamma-ray dosages used for mutagenesis in C. elegans are 6000- 8000 r. From our data we conservatively estimated that 43% of rearrangements induced with 8000 r would be accompanied by additional chromosome breaks in the genome. With 1500 r the value was 5%. The 35 lethals studied were derived from 875 screened F1's. Among these lethals there were (1) at least two unc-36 duplications, (2) at least four translocations, (3) at least six deficiencies of chromosome V (these delete about 90% of the unc-60 to unc-42 region) and (4) several unanalyzed rearrangements. Thus, it is possible to recover desired rearrangements at reasonable rates with a dose of only 1500 r. We suggest that the levels of ionizing radiation employed in most published C. elegans studies are excessive and efforts should be made to use reduced levels ------------------- Key: 751 Medline: 85155450 Authors: Cox GN;Carr S;Kramer JM;Hirsh D Title: Genetic mapping of C. elegans collagen genes using DNA polymorphisms as phenotypic markers. Citation: Genetics 109: 513-528 1985 Type: ARTICLE Genes: col-2 col-3 col-4 col-5 col-6 col-8 col-9 Abstract: In Caenorhabditis elegans collagens comprise a dispersed family of 40- 150 genes, the majority of which probably code for collagen proteins found in the animal's cuticle. The conserved (Gly-X-Y)n triple helix coding sequence of collagen genes has facilitated the isolation of a large number of C. elegans collagen genes by recombinant DNA methods. We have begun a study of the chromosomal organization of these genes by screening laboratory strains of C. elegans for DNA polymorphisms in the regions surrounding collagen genes. Polymorphisms near seven genes have been identified and have been used as phenotypic markers in genetic crosses to assign the genes to linkage groups II, III, IV, and X. Four genes are shown by multifactor crosses to map to a 2-3 map unit interval between unc-24 and unc-22 on chromosome IV. ------------------- Key: 752 Medline: Authors: Lozano R;Lusby WR;Chitwood DJ;Svoboda JA Title: Dealkylation of various 24-alkylsterols by the nematode C. elegans. Citation: Lipids 20: 102-107 1985 Type: ARTICLE Genes: Abstract: The metabolism of 4 dietary 24-alkylsterols was investigated in the free-living nematode Caenorhabditis elegans. The major unesterified sterols of C. elegans in media supplemented with either campesterol, 22-dihydrobrassicasterol or stigmasterol included cholesta-5,7-dienol, cholesterol, cholest-7-enol, and 4a-methylcholest-8(14)-enol. Dietary stigmastanol yielded cholest-7-enol, cholestanol, cholest-8(14)-enol, and 4a-methylcholest-8(14)-enol as major unesterified sterols. Esterified sterols comprised less than 22% of the total sterol. Removal of a C-24 ethyl substituent of sterols was neither hindered by the presence of a delta22-bond in the sterol side chain nor was it dependent on unsaturation in ring B of the steroid nucleus. C. elegans reduced a delta22-bond during its metabolism of stigmasterol; it did not introduce a delta5-bond during stigmastanol metabolism. C. elegans was capable of removing a C-24 methyl substituent regardless of it stereochemical orientation. Metabolic processes involving the steroid ring system of cholesterol (C-7 dehydrogenation, delta5-reduction, 4a-methylation, delta8(14)-isomerization) in C. elegans were not hindered by the presence of a 24-methyl group; various 24-methylsterol metabolites from campesterol were detected, mostly 24-methylcholesta-5,7-dienol. In contrast, no 24-ethylsterol metabolites from the dietary ethylsterols were found. More dietary 24-methylsterol remained unmetabolized than did dietary 24-ethylsterol. A 24a-ethyl group and a 24B-methyl group were dealkylated to a greater extent by C. elegans than was a 24a-methyl group, perhaps reflecting the substrate specificity of the dealkylation enzyme system, or suggesting different enzymes ------------------- Key: 753 Medline: 85101872 Authors: Jeyaprakash A;Jansson H-B;Marban-Mendoza N;Zuckerman BM Title: C. elegans: Lectin-mediated modification of chemotaxis. Citation: Experimental Parasitology 59: 90-97 1985 Type: ARTICLE Genes: che-3 daf-6 Abstract: Binding of the lectins concanavalin A (Con A) and limulin to Caenorhabditis elegans wild type resulted in consistent, reproducible, partial inhibition of chemoattraction to sterile filtrates of Escherichia coli. Normal chemotaxis resumed within 8 hr following treatment with these lectins. Competitive displacement of Con A or limulin by flooding with the specific sugars resulted in rapid resumption of normal chemotactic behavior. The experimental protocol for Con A applied to three age groups (newly hatched larvae, young adults, and old adults) showed the same response for all groups tested. Two mutant C. elegans with morphological defects in the cephalic chemosensilla showed the same inhibition of chemotactic response after exposure to Con A, and rapidly resumed normal behavior after competitive displacement of the lectin. Limulin and Con A did not affect nematode growth, development, or longevity, demonstrating that the observed results were not attributable to toxic effects. These results and other experimental evidence support the premise that behavioral modification was caused by functional impairments caused by Con A and limulin to chemoreceptors located on sensory dendrites of the cephalic sensilla. ------------------- Key: 754 Medline: Authors: Hosono R;Kuno S Title: Properties of the unc-52 gene and its related mutations in the nematode C. elegans. Citation: Zoological Science 2: 81-88 1985 Type: ARTICLE Genes: lin-7 unc-52 unc-54 cnDp1 Abstract: The mutations in the unc-52 gene show a stage-dependent uncoordinated (Unc) phenotype and belong to either severely or mildly paralyzed Unc. One recessive allele (cn10) of the unc-52 gene, belonging to one of the most severely paralyzed group, and its revertans are depicted. Isolated as a revertant of the severe allele, unc-52 (cn10) cnDp1 (f) produces two types of progeny; parental severe-type and recovered mild-type Unc. Genetic evidence is presented showing that the property of cnDp1 is brought about by the presence (i.e., mild type) or absence (i.e., severe type) of the free chromosomal fragment containing the unc-52 (cn10) gene. Based on the properties of the strain containing cn Dp1 (f), the role of the unc-52 gene is ------------------- Key: 755 Medline: 85166210 Authors: Eide D;Anderson P Title: Transposition of Tc1 in the nematode C. elegans. Citation: Proceedings of the National Academy of Sciences USA 82: 1756-1760 1985 Type: ARTICLE Genes: unc-15 unc-54 unc-105 Abstract: We have identified a strain of Caenorhabditis elegans in which the transposable element Tc1 is genetically active. Most spontaneous mutations affecting the unc-54 myosin heavy chain gene of C. elegans variety Bergerac are due to insertions of Tc1 within unc-54. The Bergerac genome contains an unusually high number of Tc1 elements, but this is not responsible for transpositional activity. Another variety of C. elegans, strain DH424, contains an equally high number of Tc1 elements, but transpositions are not detected. Tc1 insertion mutations are genetically unstable. They revert to unc-54+ in both germ-line and somatic cells. Germ-line revertants are wild type and contain precise or nearly precise excisions of Tc1. Somatic revertants are genetic mosaics; they contain small patches of revertant muscle tissue in otherwise mutant animals. The pattern of mosaicism often allows us to know when and where during muscle development the excisions occur. Somatic reversion can be over 1000- fold more frequent than germ-line reversion. ------------------- Key: 756 Medline: 85133850 Authors: Okamoto H;Thomson JN Title: Monoclonal antibodies which distinguish certain classes of neuronal and support cells in the nervous tissue of the nematode C. elegans. Citation: Journal of Neuroscience 5: 643-653 1985 Type: ARTICLE Genes: ced-3 Abstract: Monoclonal antibodies were generated using mice immunized with total homogenates of Caenorhabditis elegans adults or early larvae. Two of them were shown to distinguish a certain class of neuronal or supporting cells in the nervous tissue of this animal. Their histological specificities were studied in detail by indirect immunofluorescence on a whole mount preparation of animal head (or tail); for one of the antibodies further analysis was done by immunoelectron microscopy with the aid of a colloidal gold probe. An application of this antibody to a mutant of C. elegans is also described. ------------------- Key: 757 Medline: 85187377 Authors: Lozano R;Lusby WR;Chitwood DJ;Thompson MJ;Svoboda JA Title: Inhibition of C-28 and C-29 phytosterol metabolism by N, N-dimethyldodecanamine in the nematode C. elegans. Citation: Lipids 20: 158-166 1985 Type: ARTICLE Genes: Abstract: Effects on the metabolism of campesterol and stigmasterol in Caenorhabditis elegans were investigated using N,N- dimethyldodecanamine, a known inhibitor of growth, reproduction and the delta 24-sterol reductase of this nematode. 7-Dehydrocholesterol was the predominant sterol (51%) of C. elegans grown in stigmasterol- supplemented media, whereas addition of 25 ppm amine resulted in a large decrease in the relative percentage of 7-dehydrocholesterol (23%) and the accumulation of a substantial proportion (33%) of delta 24-sterols (e.g., cholesta-5,7,24-trienol) and delta 22,24-sterols (e.g., cholesta-5,7,22, 24-tetraenol) but yielded no delta 22- sterols. Dealkylation of stigmasterol by C. elegans proceeded in the presence of the delta 22-bond; reduction of the delta 22-bond occurred prior to delta 24-reduction. Addition of 25 ppm amine to campesterol-supplemented media altered the sterol composition of C. elegans by increasing the percentage of unmetabolized dietary campesterol from 39 to 60%, decreasing the percentage of 7- dehydrocholesterol from 26 to 12%, and causing the accumulation of several delta 24-sterols (6%). C. elegans also was shown to be capable of dealkylating a delta 24 (28)-sterol as it converted 24- methylenecholesterol to mostly 7-dehydrocholesterol. The proposed role of 24-methylenecholesterol as an intermediate between campesterol and 7-dehydrocholesterol was supported by the ------------------- Key: 758 Medline: Authors: Johnson TE Title: Analysis of the biological basis of aging in the nematode with special emphasis on C. elegans. Citation: "Invertebrate Models in Aging Research." Mitchell DH and Johnson TE (eds), CRC Press, Boca Raton, FL. : 59-93 1983 Type: REVIEW Genes: dpy-8 her-1 lon-2 unc-2 unc-15 unc-20 unc-54 unc-78 Abstract: In the preparation of this review, I have made the basic assumption that the desire of the reader is to understand the biological basis of organismic aging. Given this premise, the organism of choice should be one that offers the most immediate hope of arriving at such an understanding. An ideal organism should have a short lifespan; be inexpensive to maintain; be experimentally malleable by a variety of techniques including molecular, morphological, genetic, and biological approaches; and be the object of study in a sufficient number of different laboratories to assure the accumulation of a critical mass of data. The nematode, Caenorhabditis elegans, admirably fulfills all of these basic requirememts. Researchers in the field of aging are faced with a large number of different theories which purport to explain the molecular basis of organismic aging. There are two major reasons for this proliferation of theoretical views. First, aging is an extremely complex phenomenon involving changes in a number of different physiological systems; these physiological changes are often detected, but proof that any one of the changes is responsible for aging is lacking. Second, the focus of a great deal of the research in the field has not been so much on understanding the biological basis of the entire aging process as on understanding one or another of the consequences of this process, particularly in humans and other mammals. The mammalian model systems may often be quite inappropriate for addressing the more basic, long-term questions about the ------------------- Key: 759 Medline: Authors: Klass M Title: Cell-specific gene expression in C. elegans. Citation: "Invertebrate Models in Aging Research." Mitchell DH and Johnson TE (eds), CRC Press, Boca Raton, FL. : 45-58 1984 Type: REVIEW Genes: Abstract: ------------------- Key: 760 Medline: Authors: Curran J;Baillie DL;Webster JM Title: Use of genomic DNA restriction fragment length differences to identify nematode species. Citation: Parasitology 90: 137-144 1985 Type: ARTICLE Genes: Abstract: Restriction endonuclease digestion of genomic DNA generates DNA fragments of unique size, dependent upon the particular base sequence. Following fractionation by agarose gel electrophoresis, repetitive DNA can be visualized as distinct bands in stained gels and the restriction fragment length of such bands used as diagnostic characters. Restriction fragment length differences were detected between species within the genera Trichinella, Caenorhabditis, Romanomermis, Steinernema (syn. Neoaplectana) and Meloidogyne. This technique provides a new tool for the taxonomist, which is independent of phenotypic variation and it enables the rapid and reliable separation of closely related species. ------------------- Key: 761 Medline: 85124602 Authors: Herman RK;Kari CK Title: Muscle-specific expression of a gene affecting acetylcholinesterase in the nematode C. elegans. Citation: Cell 40: 509-514 1985 Type: ARTICLE Genes: ace-1 ace-2 daf-6 sup-10 unc-3 unc-93 mnDp14 Abstract: We have generated C. elegans animals that carry a duplication as a free chromosome fragment bearing an ace-1+ gene in an otherwise homozygous ace-1 ace-2 genetic background. The single ace-1+ gene in these animals is responsible for coordinated animal movement and acetylcholinesterase activity in the regions of the nerve ring and ventral and dorsal nerve cords, as judged by histochemical assay. We have used other genes on the free duplication whose cell-specific expressions have already been elucidated to identify particular genetic mosaics produced by spontaneous somatic loss of the duplication. The analysis of these mosaics has led us to conclude that the synthesis of acetylcholinesterase by muscle cells is primarily responsible for the coordinated movement conferred by the ace-1+ gene. ------------------- Key: 762 Medline: 85205300 Authors: Ferguson EL;Horvitz HR Title: Identification and characterization of 22 genes that affect the vulval cell lineages of the nematode C. elegans. Citation: Genetics 110: 17-72 1985 Type: ARTICLE Genes: let-23 let-60 lin-1 lin-2 lin-3 lin-4 lin-7 lin-8 lin-9 lin-10 lin-11 lin-12 lin-13 lin-15 lin-17 lin-18 lin-24 lin-25 lin-26 lin-31 lin-33 nT1 Abstract: Ninety-five mutants of the nematode Caenorhabditis elegans altered in the cell lineages of the vulva have been isolated on the basis of their displaying one of two phenotypes, Vulvaless or Multivulva. In Vulvaless mutants, which define 12 genes, no vulva is present. In Multivulva mutants, which define ten genes, one or more supernumerary vulva-like protrusions are located along the ventral side of the animal. A single recessive mutation is responsible for the phenotypes of most, but not all, of these strains. Fifteen of these 22 genes are represented by multiple alleles. We have shown by a variety of genetic criteria that mutations that result in a Vulvaless or Multivulva phenotype in six of the 22 genes most likely eliminate gene function. In addition, Vulvaless or Multivulva mutations in seven of the other genes most likely result in a partial reduction of gene function; the absence of the activity of any of these genes probably results in lethality or sterility. Our results suggest that we may have identified most, or all, genes of these two classes. ------------------- Key: 763 Medline: Authors: Ouazana R;Garrone R;Godet J Title: Characterization of morphological and biochemical defects in the cuticle of a dumpy mutant of C. elegans. Citation: Comparative Biochemistry & Physiology 80B: 481-483 1985 Type: ARTICLE Genes: dpy-5 dpy-15 Abstract: 1. In this paper, we describe morphological and biochemical cuticle defects in a dumpy mutant of Caenorhabditis elegans. 2. This mutant, FF31, exhibits major alterations in internal cuticle architecture when compared to the wild-type strain. 3. SDS-polyacrylamide gel electrophoresis of the soluble cuticle proteins of this mutant also reveals differences when compared to the proteins of the wild-type. 4. To minimize the possibility that the morphological and biochemical defects are caused by different mutations, we have isolated a revertant strain, FF102, with normal body shape after EMS mutagenesis on FF31 larvae and we have shown that the morphological and biochemical defects revert as well. 5. This suggests that all the modifications displayed by this mutant are the ------------------- Key: 764 Medline: Authors: Swanson MM;Edgley ML;Riddle DL Title: The nematode Caenorhabditis elegans. Citation: Genetic Maps 3: 286-299 1984 Type: REVIEW Genes: Abstract: ------------------- Key: 765 Medline: 85159849 Authors: Chalfie M;Sulston JE;White JG;Southgate E;Thomson JN;Brenner S Title: The neural circuit for touch sensitivity in C. elegans. Citation: Journal of Neuroscience 5: 956-964 1985 Type: ARTICLE Genes: Abstract: The neural pathways for touch-induced movement in Caenorhabditis elegans contain six touch receptors, five pairs of interneurons, and 69 motor neurons. The syaptic relationships among these cells have been deduced from reconstructions from serial section electron micrographs, and the roles of the cells were assessed by examining the behavior of animals after selective killing of precursors of the cells by laser microsurgery. This analysis revealed that there are two pathways for touch-mediated movement for anterior touch (through the AVD and AVB interneurons) and a single pathway for posterior touch (via the PVC interneurons). The anterior touch circuitry changes in two ways as the animal matures. First, there is the formation of a neural network of touch cells as the three anterior touch cells become coupled by gap junctions. Second, there is the addition of the AVB pathway to the pre-existing AVD pathway. The touch cells also synapse onto many cells that are probably not involved in the generation of movement. Such synapses suggest that stimulation of these receptors may modify a number of behaviors. ------------------- Key: 766 Medline: 85239914 Authors: Golden JW;Riddle DL Title: A gene affecting production of the C. elegans dauer-inducing pheromone. Citation: Molecular & General Genetics 198: 534-536 1985 Type: ARTICLE Genes: daf-22 Abstract: A nematode mutant lacking pheromone activity does not enter the developmentally arrested dispersal stage called the dauer larva unless exogenous pheromone is added to the growth medium, indicating that the pheromone is required for wild-type dauer larva formation. In contrast, a class of temperature-sensitive mutant forms dauer larvae even in the absence of detectable pheromone, indicating that such mutants bypass the normal pheromone requirement. A rapid bioassay of pheromone produced by individual nematodes has been developed for genetic analysis of pheromone ------------------- Key: 767 Medline: 85201409 Authors: Karn J;Dibb NJ;Miller DM Title: Cloning nematode myosin genes. Citation: "Cell and Muscle Motility." Shay JW (ed), Plenum Press. 6: 185-237 1985 Type: REVIEW Genes: Abstract: ------------------- Key: 768 Medline: 83232892 Authors: Wills N;Gesteland RF;Karn J;Barnett L;Bolten S;Waterston RH Title: The genes sup-7 X and sup-5 III of C. elegans suppress amber nonsense mutations via altered transfer RNA. Citation: Cell 33: 575-583 1983 Type: ARTICLE Genes: sup-5 sup-7 unc-54 Abstract: The sup-5 III and sup-7 X suppressors in C. elegans have previously been shown to have many genetic properties in common with tRNA nonsense suppressors of microorganisms. We report here the results of two lines of investigation into the molecular basis of these suppressors. In one, which sought to determine the nature of suppressible alleles, we demonstrate through DNA sequencing studies that a suppressible allele, unc-54(e 1300) I, of the myosin heavy chain gene contains a C leads to T substitution, which changes a glutamine codon to amber terminator at residue 1903. In the other approach, which sought to define the nature of the suppressing activity, we show through in vitro translation studies that tRNA fractions from the suppressor strains, but not wild-type, promote the specific readthrough of amber terminators of three different messenger RNAs. We conclude that sup-5 and sup-7 result in readthrough of amber terminators in vivo through an altered ------------------- Key: 769 Medline: 85258981 Authors: Brown SJ;Riddle DL Title: Gene interactions affecting muscle organization in C. elegans. Citation: Genetics 110: 421-440 1985 Type: ARTICLE Genes: dpy-10 dpy-17 dpy-18 lon-1 sqt-1 sup-3 sup-19 sus-1 unc-15 unc-82 Abstract: Revertants of unc-15(e73)I, a paralyzed mutant with an altered muscle paramyosin, include six dominant and two recessive intragenic unc-15 revertants, two new alleles of the previously identified suppressor gene, sup-3 V, and a new suppressor designated sup-19(m210)V. The recessive intragenic unc-15 revertants exhibit novel alterations in paramyosin paracrystal structure and distribution, and these alterations are modified by interaction with unc-82(e1220)IV, another mutation that affects paramyosin. A strain containing both unc-15 and a mutation in sup-3 V that restores movement was mutagenized, and paralyzed mutants resembling unc-15 were isolated. Twenty mutations that interfere with suppression were divided into three classes (nonmuscle, sus-1, and mutations within sup-3) based on phenotype, genetic map position and dominance. The nonmuscle mutations include dumpy and uncoordinated types that have no obvious direct effect on muscle organization. Two recessive mutations define a new gene, sus-1 III. These mutations modify the unc-15(e73) phenotype to produce a severely paralyzed, dystrophic double mutant that is not suppressed by sup-3. Five semidominant, intragenic sup-3 antisuppressor mutations, one of which occurred spontaneously, restore the wild-type sup-3 phenotype of nonsuppression. However, reversion of these mutants generated no new suppressor alleles of sup-3, suggesting that the sup-3 antisuppressor alleles are not wild type but ------------------- Key: 770 Medline: Authors: Epstein HF;Ortiz I;Berliner GC;Miller DM III Title: Nematode thick-filament structure and assembly. Citation: "Molecular Biology of the Cytoskeleton." Borisy G, Cleveland D and Murphy D (eds), Cold Spring Harbor Laboratory. : 275-286 1985 Type: REVIEW Genes: Abstract: Myosins from slime molds to brain cells show a remarkable commonality of general molecular properties. These characteristics include two globular domains or heads that contain ATPase and actin-binding sites and the fibrous, coiled-coil a-helical rod that interacts with other molecules in assembly. Two heavy chains (m.w. 200,000) contribute to both heads, whereas two kinds of light chains bind to each head. In this paper, we consider striated muscles and their myosins. The phylogenetically distant nematode body-wall muscles and rabbit fast skeletal muscles produce myosin heavy chains, with about 47% of the amino acid sequences in the heads and 37% of the amino acids in the rod being identical (Karn et al. 1984). Myosin heavy chains are therefore highly conserved proteins. Contrasting with the phylogenetic conservation of myosin structure and sequence is the diversity of supramolecular arrangements of myosin assemblies in striated muscles, the so-called thick filaments. The lengths of thick filaments range from 1.55 um in vertebrates, 2-4 um in insect flight muscles, 10 um in the nematode to 40 um in certain mollusks. The average diameters of these filaments range from about 15 nm in vertebrates, 20 nm in insects, 25 nm in nematodes to 50-100 nm in some molluscan muscles. The surface arrangements of the myosin heads also vary in these different species. The lattice arrangements between thick filaments and the interdigitating, actin-containing thin filaments differ in terms of symmetry and thick:thin stoichiometry between these muscles. It appears likely that other protein components of these muscles interact with the very similar myosins to produce this structural diversity. The relatively subtle differences between myosin isoforms may also be important in these interactions. We define isoform in the case of myosin, for example, as a protein that is defined as a myosin by biochemical criteria but that can be distinguished on the basis of intrinsic molecular structure from another myosin within the same organism. In this paper, we describe experiments suggesting that two genetically different isoforms of myosin play distinct roles in concert with other proteins during the assembly of thick filaments in ------------------- Key: 771 Medline: 85131340 Authors: Epstein HF;Miller DM III;Ortiz I;Berliner GC Title: Myosin and paramyosin are organized about a newly identified core structure. Citation: Journal of Cell Biology 100: 904-915 1985 Type: ARTICLE Genes: Abstract: Myosin isoforms A and B are differentially localized to the central and polar regions, respectively, of thick filaments in body wall muscle cells of Caenorhabditis elegans (Miller, D.M. III, I. Ortiz, G.C. Berliner, and H.F. Epstein, 1983, Cell, 34: 477-490). Biochemical and electron microscope studies of KCl-dissociated filaments show that the myosin isoforms occupy a surface domain, paramyosin constitutes an intermediate domain, and a newly identified core structure exists. The diameters of the thick filaments vary significantly from 33.4 nm centrally to 14.0 nm near the ends. The latter value is comparable to the 15.2 nm diameter of the core structures. The internal density of the filament core appears solid medially and hollow at the poles. The differentiation of thick filament structure into supramolecular domains possessing specific substructures of characteristic stabilities suggests a sequential mode for thick filament assembly. In this model, the two myosin isoforms have distinct roles in assembly. The behavior of the myosins, including nucleation of assembly and determination of filament length, depend upon paramyosin and the core structure as well as their intrinsic molecular properties. ------------------- Key: 772 Medline: 85295957 Authors: Russnak RH;Candido EPM Title: Locus encoding a family of small heat-shock genes in C. elegans: Two genes duplicated to form a 3.8-kilobase inverted repeat. Citation: Molecular and Cellular Biology 5: 1268-1278 1985 Type: ARTICLE Genes: Abstract: The genes coding for hsp 16-48, previously identified by cDNA cloning, and for another 16-kilodalton heat shock protein designated hsp16-1 were characterized by DNA sequencing. The two genes were arranged in a head-to-head orientation. Both the coding and flanking regions were located within a 1.9-kilobase module which was duplicated exactly to form a 3.8-kilobase inverted repeat structure. The inverted repeat structure ended in an unusual guanine-plus- cytosine-rich sequence 24 nucleotides in length. The identity of the two modules at the nucleotide sequence level implies that the duplication event may have occurred recently. Alternatively, gene conversion between the two modules could also maintain homology of the two gene pairs. The small heat shock genes of Caenorhabditis elegans contained TATA boxes and heat-inducible promoters, the latter agreeing closely with the Drosophila melanogaster consensus sequence described by Pelham (Cell 30:517-528, 1982). Unlike the homologous D. melanogaster genes, each of these C. elegans genes contained a short intron, the position of which has been conserved in a related murine alpha-crystallin gene. The intron separated variable and conserved regions within the amino acid sequences of the encoded heat shock polypeptides. ------------------- Key: 773 Medline: 85223144 Authors: Morgan PG;Cascorbi HF Title: Effect of anesthetics and a convulsant on normal and mutant C. elegans. Citation: Anesthesiology 62: 738-744 1985 Type: ARTICLE Genes: Abstract: The authors have developed a method for studying the action of volatile anesthetics in Caenorhabditis elegans (C.e.), a free living nematode. C.e. appears to be a useful model for the study of the influence of genetics on susceptibility to anesthetics. This worm has a small, completely defined nervous system, easily manipulated genetics, and a large number of nervous system mutants. Under normal conditions C.e. moves almost constantly. When exposed to anesthetics there is an initial phase of increased locomotion, followed by uncoordinated motion that progresses to immobility. Motion returns quickly when the nematodes are removed from the anesthetic. The authors called loss of locomotion "anesthesia." The ED50S of various anesthetics with C.e. are as follows: methoxyflurane 0.45%, chloroform 1.25%, halothane 2.7%, enflurane 4.2%, isoflurane 5.6%, fluroxene 9.9%. The authors also studied the action of a convulsant, flurothyl, on C.e. Flurothyl has anesthetizing properties in these animals with an ED50 of 8.1%. No convulsant activity was noted. However, mixtures of halothane and flurothyl were antagonistic in their effects, while halothane and enflurane were additive. Furthermore, the authors isolated a mutant strain (HS1) of C.e. that shows altered responses to several anesthetics and a convulsant. HS1 is uncoordinated when not exposed to anesthetics. Like the normal strain (N2) HS1 loses mobility when exposed to anesthetics. The ED50S for various anesthetics in HS1 were as follows: methoxyflurane 0.04%, chloroform 0.52%, halothane 0.85%, isoflurane 4.9%, enflurane 6.0%, fluroxene 10.9%.(ABSTRACT TRUNCATED AT 250 WORDS) ------------------- Key: 774 Medline: 85243050 Authors: Burr AH Title: The photomovement of C. elegans, a nematode which lacks ocelli. Proof that the response is to light not radiant heating. Citation: Photochemistry and Photobiology 41: 577-582 1985 Type: ARTICLE Genes: Abstract: Caenorhabditis elegans adults were tested at constant temperature with 10 s periods of monochromatic light alternated with 20 s dark periods. Stimuli at effective intensities and wavelengths caused an increase in the frequency of ecclitic (phobic, avoidance) responses, which was measured as an increase in the probability of a temporary reversal in direction of movement. For monochromatic stimuli ranging from 420 to 680 nm at a constant 56 picoeinsteins s-1 cm-2, only those at 520-600 nm elicited significant responses. At 540 nm the threshold fluence rate was approximately 30 pE s-1 cm-2. At saturating intensities the mean reversal probability was increased to 0.20 in 10 s from a background level of 0.12, approximately. Because C. elegans lacks ocelli and is very sensitive to temperature, possible sources of radiant heating were considered in detail, including (a) infrared present in the stimuli, (b) absorption of light by the arena, and (c) absorption of light by a nematode pigment. All possible sources were found to cause a negligible temperature rise, on the order of or less than the natural temperature fluctuations inside the worm, 1.5 X 10-6 C. A 2 X 10-4 C temperature rise produced by a 1230 nm infrared stimulus had no significant effect on reversal frequency. It was concluded that the response to illumination must have been to light, and not to temperature changes. Large, + or - 2 C changes from the acclimation temperature caused significant increases in the background frequency of ecclitic responses (a thermoecclisis or thermoklinokinesis). However, neither the threshold nor the saturation level of light-induced responses was ------------------- Key: 775 Medline: 85216652 Authors: Stinchcomb DT;Mello C;Hirsh D Title: C. elegans DNA that directs segregation in yeast cells. Citation: Proceedings of the National Academy of Sciences USA 82: 4167-4171 1985 Type: ARTICLE Genes: Abstract: We have isolated seven DNA fragments from Caenorhabditis elegans that enhance the mitotic segregation of autonomously replicating plasmids in the yeast Saccharomyces cerevisiae. These segregators, designated SEG1-SEG7, behave like isolated yeast chromosomes: they increase the stability and simultaneously lower the copy number of circular plasmids during mitotic growth in yeast. During meiosis, plasmids containing the C. elegans segregators show higher levels of precocious or aberrant disjunction than do plasmids bearing isolated yeast centromeres. Yet one of the segregators improved the meiotic segregation of the parental plasmid. We estimate that there may be as many as 30 segregator sequences in the C. elegans genome, a value that is consistent with the polycentric nature of C. elegans chromosomes. Five of the seven segregators are linked to sequences that are repeated in the worm genome, and four of these five segregators cross-hybridize. Other members of this family of repetitive DNA do not contain segregator function. Segregator sequences may prove useful for probing the structure of centromeres of both C. elegans and S. cerevisiae ------------------- Key: 776 Medline: 85204208 Authors: Jameel S;McFadden BA Title: C. elegans: Purification of isocitrate lyase and the isolation and cell-free translation of poly(A+)RNA. Citation: Experimental Parasitology 59: 337-346 1985 Type: ARTICLE Genes: Abstract: Isocitrate lyase (EC 4.1.3.1) from mixed larval populations of Caenorhabditis elegans was stabilized in crude extracts by centrifugation over a 0.2-0.6 M sucrose gradient for 2.5 hr in a vertical rotor (VTi 50) at 210,000g. The peak fractions from this sucrose gradient showed a half-life of 33 hr at 30 C and 225 hr at 4 C in contrast to 2.5 and 52 hr, respectively, for the crude extract. A purification scheme involving (NH4)2SO4 precipitation and chromatography on Sepharose 6B and diethylaminoethyl-cellulose yielded isocitrate lyase that gave one band after electrophoresis in a sodium dodecyl sulfate-gel polymerized from 12% acrylamide. The purified enzyme with a molecular weight of 250,000 and subunit molecular weight of 61,600, had a specific activity of 2 mumoles glyoxylate formed min-1 mg protein-1, and was obtained in a 4% yield. Isocitrate lyase from C. elegans lost 80-85% of its activity in the precipitation by 33-55% (NH4)2SO4, but this step appeared to be necessary for purification to homogeneity. The use of fast protein liquid chromatography appeared to be promising in that it provided an enzyme preparation that was about 50% pure with a specific activity as high as 3 mumoles glyoxylate formed min-1 mg protein-1. Poly(A+)RNA was isolated from C. elegans and translated in wheat germ cell-free system. Analysis on a 10% sodium dodecyl sulfate- polyacrylamide gel showed varied translation products including one or more 60,000-Da polypeptides. ------------------- Key: 777 Medline: Authors: Schierenberg E;Carlson C;Sidio W Title: Cellular development of a nematode: 3-D computer reconstruction of living embryos. Citation: Roux's Archives of Developmental Biology 194: 61-68 1985 Type: ARTICLE Genes: Abstract: Embryos of the free-living soil nematode Caenorhabditis elegans are capable of developing normally outside the mother; we have monitered this process in isolated embryos by light microscopy and recorded it on video tape. The size and position of each nucleus were entered into a computer at short time intervals from the 2- to 102-cell stages. Models were reconstructed in which nuclei are represented by spheres and assigned different colors and patterns according to lineage membership. Three-dimensional reconstructions aid visualization of the spatial arrangement of nuclei and demonstrate the small degree of positional variance among individuals. The dynamic processes of nuclear growth during the cell cycle, division, migration, and pattern formation can be quantitatively analyzed. Our knowledge of the complete embryonic lineage allows the correlation of nuclear ------------------- Key: 778 Medline: Authors: Meheus L;Vanfleteren JR Title: Nematode chromosomal proteins - IV. The nonhistones of C. elegans. Citation: Comparative Biochemistry & Physiology 81B: 377-383 1985 Type: ARTICLE Genes: Abstract: 1. A method has been developed which yields reasonably clean nuclei from the free-living nematode Caenorhabditis elegans. Nonhistones were prepared from these nuclei by gentle extraction with 2 M NaCl and analyzed by one- and two-dimensional electrophoresis using a nonequilibrium pH gradient electrophoresis in the first dimension after removal of nucleic acids by phenol extraction. 2. The extraction procedure yielded nonhistone chromatin proteins and proteins associated with nuclear RNA and a background of polypeptides derived from the nuclear matrix and pore-lamina complex. 3. Over 40 polypeptides were distinguished on silver stained one-dimensional slab gels. 4. The presence of actin, tropomyosin and tubulin was demonstrated by immunoprobing after transfer of the polypeptides to nitrocellulose. 5. Bands co-migrating with myosin and a-actinin gave no specific reaction when probed with antibodies raised against the respective proteins from vertebrate tissues. 6. Over 200 spots were visible on two-dimensional gels stained with silver nitrate. ------------------- Key: 779 Medline: 85264809 Authors: Dibb NJ;Brown DM;Karn J;Moerman DG;Bolten SL;Waterston RH Title: Sequence analysis of mutations that affect the synthesis, assembly and enzymatic activity of unc-54 myosin heavy chain of C. elegans. Citation: Journal of Molecular Biology 183: 543-551 1985 Type: ARTICLE Genes: unc-54 Abstract: We have sequenced 11 representative mutations of the unc-54 myosin heavy chain gene of Caenorhabditis elegans that affect the synthesis, assembly or enzymatic activity of the encoded myosin heavy chain. Six of the sequenced unc-54 mutations cause premature termination of protein synthesis. Four mutations (e1092, e1115, e1213, e1328) were ochre mutations, one mutation (e903) was a frameshift, which caused premature termination at a nearby UGA terminator, and one mutation (e190) was a deletion that altered the reading frame and caused termination at an ochre codon. Two mutations (e675 and s291) were inphase deletions, which resulted in a shortened myosin rod segment. These aberrant myosins fail to assemble into normal thick filaments. The sequence alterations of the missense mutations (e1152, s74, s95) indicated amino acid residues that are critical for myosin function. The mutation e1152 causes the production of a myosin heavy chain that fails to assemble into thick filaments. It had two adjacent amino acid substitutions at the extreme amino terminus of the rod, indicating a role for subfragment-2 in thick filament assembly. Mutants homozygous for s74 or s95 are very slow-moving, although they make myosin heavy chains that assemble normally. The encoded amino acid substitutions of s95 and s74 are in the 23 X 10(3) Mr and 50 X 10(3) Mr domains of the myosin head, flanking the ATP binding site. The sequenced mutations are distributed throughout the gene in the order predicted from genetic fine-structure mapping experiments. Seven of eight point mutations isolated following ethylmethane sulphonate mutagenesis were G X C to A X T transitions. A single X- ray-induced allele proved to be a deletion of two adjacent thymidine residues. The three deletion mutations were found in a region of the myosin rod with numerous direct and inverted nucleotide sequence repeats, but their origin cannot be accounted for by homologous recombination. Instead, a comparison of the deletion junctions suggests that the deletions arose by a site-specific mechanism. ------------------- Key: 780 Medline: 85234504 Authors: Sanford T;Prenger JP;Golomb M Title: Purification and immunological analysis of RNA polymerase II from C. elegans. Citation: Journal of Biological Chemistry 260: 8064-8069 1985 Type: ARTICLE Genes: ama-1 Abstract: We describe a rapid procedure for obtaining highly purified RNA polymerase II from the nematode Caenorhabditis elegans. The structure of the enzyme was examined by denaturing gel electrophoresis and found to consist of three large polypeptides (molecular weights 200,000, 175,000, and 135,000) and eight smaller polypeptides (molecular weights 29,500, 20,000, 16,000, 15,000, 13,000, 11,500, 10,500, and 9,500). As observed for the analogous enzyme from other organisms, the 175,000 polypeptide (II175) appeared to be a degraded form of the 200,000 polypeptide (II200). The structure of nematode RNA polymerase II closely resembles that of the corresponding enzyme from other animals. Four of its larger subunits shared antigenicity with Drosophila RNA polymerase II. Antibody raised against purified RNA polymerase II reacted with several enzyme subunits in "Western" blots of purified polymerase and impure enzyme fractions. Immunofluorescence staining was used to visualize RNA polymerase II in the nuclei of a nematode squash preparation and the nucleoplasm of cultured ------------------- Key: 781 Medline: 85266434 Authors: Johnson TE;McCaffrey G Title: Programmed aging or error catastrophe? An examination by two-dimensional polyacrylamide gel electrophoresis. Citation: Mechanisms of Ageing & Development 30: 285-297 1985 Type: ARTICLE Genes: fer-15 Abstract: We have examined newly synthesized proteins in the young adult and in older populations of the nematode Caenorhabditis elegans using two- dimensional polyacrylamide gel electrophoresis (2D PAGE). A temperature-sensitive mutant strain, DH26, with a mean life span of about 15 days, under our conditions, was used to block progeny development. Nematodes of several different ages were pulse-labeled for 5 h, in vivo, with 35S-labeled E. coli, A subsequent 30-min chase with unlabeled E. coli served to rid the worms of endogenous labeled E. coli proteins. We resolve 700 or more proteins by 2D PAGE polyacrylamide gel electrophoresis of extracts of young nematodes. The patterns of these proteins are highly reproducible in comparisons of independent repeats of identical experiments. No new major proteins are synthesized at any time during the adult phase (4-22 days) nor are any of the most abundant proteins not made during this period. At our level of detectability (estimated as a satellite spot containing 4% of the amount of label in a major spot) we see no misincorporation of radioactive amino acids into newly synthesized proteins. These data are inconsistent with predictions by any one of several, so called, "error catastrophe" models of senescence and also show that modulation of the highest abundancy classes of ------------------- Key: 782 Medline: 85228243 Authors: Cowan AE;McIntosh JR Title: Mapping the distribution of differentiation potential for intestine, muscle, and hypodermis during early development in C. elegans. Citation: Cell 41: 923-932 1985 Type: ARTICLE Genes: Abstract: We have analyzed the differentiation potential of cells in early embryos of Caenorhabditis elegans by assessing the production of markers for intestinal, muscle, and hypodermal cell differentiation in cleavage-arrested blastomeres. Our results show that differentiation potential does not always segregate during cleavage in a linear fashion, i.e., a blastomere can express a differentiation potential that is absent in its parent blastomere and vice versa. Furthermore, the expression of a particular differentiation program by certain cleavage-arrested blastomeres is an exclusive event in that each cell will express only one program of differentiation, even though it may have the potential to express several. ------------------- Key: 783 Medline: 85269643 Authors: Spieth J;Denison K;Kirtland S;Cane J;Blumenthal T Title: The C. elegans vitellogenin genes: short sequence repeats in the promoter regions and homology to the vertebrate Citation: Nucleic Acids Research 13: 5283-5295 1985 Type: ARTICLE Genes: vit-1 vit-2 vit-3 vit-4 vit-5 vit-6 Abstract: The nematode Caenorhabditis elegans contains a small family of vitellogenin genes which is expressed abundantly, but only in the intestine of the adult hermaphrodite worm. In order to identify possible regulatory elements, we have sequenced the DNA surrounding the 5' ends of five of the six genes. Contained within regions which have largely diverged from one another, two different heptameric sequences are found repeated within the first 200 bp upstream of each of the genes. The first sequence, TGTCAAT, is present as a perfect heptamer at least once upstream of each gene. It is repeated in both orientations four to six times in each 5' flanking region, allowing a one-base mismatch. The second sequence, CTGATAA, is also present as a perfect heptamer in a restricted region upstream of each gene. These two sequence elements may be involved in regulation of the vitellogenin genes. Remarkably, the CTGATAA sequence is present in a similar location in the promoter regions of vertebrate vitellogenin genes. In fact, our data reveal a surprising degree of similarity between the nematode and vertebrate vitellogenins. ------------------- Key: 784 Medline: 85281823 Authors: Baillie DL;Beckenbach KA;Rose AM Title: Cloning within the unc-43 to unc-31 interval (LGIV) of the C. elegans genome using Tc1 linkage selection. Citation: Canadian Journal of Genetics & Cytology 27: 457-466 1985 Type: ARTICLE Genes: unc-22 unc-31 unc-43 Abstract: The region around the twitcher gene, unc-22, flanked by unc-43 on the left and by unc-31 on the right, has been intensively studied in our laboratory over the period of the last 8 years. In this paper we describe the identification and isolation of probes specific for several restriction fragment length differences (RFLDs) which lie within this region. Many RFLDs in Caenorhabditis elegans are caused by the insertion of a transposable element, Tc1. The method we used involved the isolation of Tc1-containing genomic fragments. These were recovered from a lambda gt 10 library of DNA from a specially constructed genetic strain containing the unc-43 to unc-31 interval from the BO strain and the rest of the genome from N2. Because the BO strain is rich in Tc1 insertion sites and the N2 strain has few, the majority of Tc1-bearing genomic fragments in the constructed strain were derived from the unc-22 region. Of nine such Tc1-bearing genomic fragments isolated, six were found which mapped within the region of interest. The 350 kilobases of genomic sequences isolated as a result of these studies are being used to study the molecular organization of this region. The method described here for Tc1 linkage selection is one that is rapid, general, and may be targeted to any genetically characterized region of ------------------- Key: 785 Medline: Authors: Waterston RH;Francis GR Title: Genetic analysis of muscle development in C. elegans. Citation: Trends in Neurosciences 8: 270-276 1985 Type: REVIEW Genes: act-1 act-3 myo-3 sup-3 unc-15 unc-45 unc-54 unc-82 unc-87 Abstract: In Caenorhabditis elegans, mutations in about 25 genes are known to alter the normal lattice structure of nematode muscle, and several of these genes have been shown to encode specific contractile proteins including a myosin heavy chain, paramyosin, and actins. These assignments have served as the basis for further genetic, molecular, and ultrastructural studies of the expression of these genes and the roles of their products in muscle assembly and function. These studies are reviewed here, and discussed in the context of the mechanisms directing the assembly of the contractile apparatus during muscle differentiation and growth. ------------------- Key: 786 Medline: Authors: White JG Title: Neuronal connectivity in C. elegans. Citation: Trends in Neurosciences 8: 277-283 1985 Type: REVIEW Genes: Abstract: The connectivity of all the 302 neurones that make up the nervous system of Caenorhabditis elegans has been deduced from reconstructions of electron micrographs of serial sec