Worm Breeder's Gazette 7(1): 65
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.
Klass and Hirsh (1976) observed that the time a nematode spends in the dauer larval stage prolongs lifespan proportionately. Our studies were designed to determine if blocking development in other larval stages also results in an extension of life proportional to the length of time spent in the blocked state. We have tried two ways of blocking development: use of accumulator mutants (to block development at various larval stages), or starvation. A battery of temperature-sensitive accumulator mutants was picked from the Hirsh collection and screened for stage of block, tightness of block, and reversibility of the block upon return to permissive conditions. Developmental stage was monitored by measuring the length of heat-killed worms with an ocular micrometer. Although many tight mutants were found in the Hirsh collection, none appeared to be readily reversible. We therefore turned to starvation blocks. Larvae can survive long periods of starvation with relatively little mortality. The mean lifespan of L1 larvae starved at the time of hatch by suspension in S Basal with no cholesterol or food is 11 days at 20 C. Upon return to growth conditions the larvae resume normal growth and development. We have found that the time spent under starvation conditions is added to the total lifespan of the worm (see Table 1). The mean lifespans suggest a correspondence between a day of starvation and a day of extra life. The standard survival statistic (Gehan) was incremented by steps of one day in estimating the best fit. [See Figure 1] We are continuing this study by looking at other ways of blocking development, as well as by extending starvation blocks to other larval stages. One problem we have encountered is that starvation after 48 hours blocks further size increase but not development. This results in mature but small adults which are killed by the hatching of unlaid eggs within the body of the mother.