Worm Breeder's Gazette 5(2): 14b
These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.
Caenorhabditis n at 20 C in thin films of Caenorhabditis briggsae Maintenance Medium (CbMM). The medium was supplemented with -sitosterol and cytochrome c. Growth of C. elegans was reduced significantly when purines and pyrimidines were removed from CbMM. Although the growth rate of C. elegans was reduced by the absence of exogenous purines and pyrimidines C. elegans grew continuously in axenic cultures for more than 100 generations. The growth rate was restored only by the replacement of adenosylic acid (AMP). The optimum concentration of AMP was 0.5 to 1 M, whereas 5 M inhibited the growth of C. elegans. Adenosine and adenine were equivalent to AMP in restoring the growth of C. elegans. Other purines (guanosine monophosphate, guanosine, guanine, inosine monophosphate, inosine, or hypoxanthine) and pyrimidines, (cytidylic acid, uridylic acid, and thymine) were ineffective in restoration of the growth. These findings suggest that C. elegans has adequate endogenous biosynthesis of pyrimidines but the purine biosynthesis is inadequate to achieve maximal growth of the nematode in CbMM. The lack of effect by exogenous purines other than the adenine group suggests that hypoxanthine (guanosine) phosphoribosyltransferase is absent in C. elegans. --Department of Nematology, University of California, Riverside, CA 92521.