Worm Breeder's Gazette 13(5): 80 (February 1, 1995)
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.
Dept. of Biology, Univ. of Miami, Coral Gables, FL 33124 We have isolated several mutants exhibiting increased life spans by exposing EMS-treated mutants of C. elegans to heat shocks, and selecting among survivors. It has previously been recognized that strains of organisms exhibiting increased life spans are more resistant to various stresses (Service, 1987; Partridge and Fowler, 1992). Our particular selection method is based on an observation made after Hurricane Andrew: power went out in the middle of an experiment comparing life expectancy of the age-1 mutant and control strain. The life expectancy of the control strain was decreased significantly, while that of the age-1 mutant was not as affected, leading to a greatly increased relative life span for the age-1 mutant. This result was shared informally with others at the 1993 meeting of the Gerontological Society of America. We presumed that some other mutants exhibiting increased life expectancy might share this characteristic of heat shock resistance. F2, F3, and F4 progeny from EMS-treated (Brenner, 1974) N2 were exposed to up to 4 rounds of heat shock over a 3-week period. Each heat shock was 38-40 degrees C. for 2-3 hrs. The animals were otherwise maintained at 20 degrees C. Most of the nematodes were killed by the heat shocks, allowing for a smaller population of survivors to be examined for life span. Worms that survived the heat shocks were transferred to fresh plates (1 worm/plate). Life spans were determined for progeny of each of these selected mutants. Several of the mutants showed significant, 10-50% increases in mean life span. Males may exhibit a greater increase in life span than hermaphrodites for one or two of the new, life-extending mutants. We have begun complementation tests with the known age-extending mutant, age-1, and hope to do complementations with the dauer (Kenyon et al, 1993) and sperm defective mutants (Van Vorhies, 1992) which also are known to extend life span. We conclude that heat shock can be used as a selection mechanism to enrich for animals exhibiting life-span extension form among a mutant population of nematodes. The effort involved in selecting for such mutants is greatly reduced from that of Klass, who generated the age-1 mutation (analyzed by Johnson and aco-workers) by searching among 8,000 mutants. We thank the CGC and Tom Johnson for strains of C. elegans, and the American Federation for Aging Research for grant support.