Worm Breeder's Gazette 1(1): 21a
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.
We have been using the sizing nematode counter (Byerly, L., Cassada, R.C., and Russell, R.L., Rev. Sci. Inst. 46, 517-521, 1975) to study the growth and reproduction of the wild type and some mutants of C. elegans. For the wild type we have obtained growth curves and egg- laying curves at 16 C, 20 C, and 25 C; growth rate shows an exponential temperature dependence with a Q10 of 2.1, but egg-laying rate does not, dropping off relative to expectation at 25 C. Egg yield is also reduced by about one-third at 25 C. As a restrictive temperature for ts mutants, 25 C seems on the borderline of acceptability, and certainly should not be exceeded. To simplify the analysis of growth and reproduction in mutants, we have been using a '3-egg' method. Cultures started from three synchronously laid eggs are allowed to develop to the point where the second-generation progeny of the original 3 animals are beginning to hatch. The resulting size distribution is then measured and a computerized fitting procedure is used to fit this distribution as closely as possible, using either wild type growth parameters or simple modifications thereof. The goodness of fit indicates how well a given mutant conforms to the wild type growth and egg-laying pattern, and the modifications indicate quantitative differences from the wild type in growth rate, egg yield, and/or size. We find this to be a very efficient way to screen mutants for growth and/or reproductive differences, and it will probably come as no surprise to learn that almost all mutants so far examined have such changes. We would be happy to examine mutants which anyone would like to send, and if anyone is interested in building a counter of his/her own ( total materials cost ~ $500; needs someone with electronics experience to construct) we would be happy to provide plans and instructions.