Worm Breeder's Gazette 1(2): 16
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.
The group of mutants previously described (Genetics 80: 279, 1975) by Sheridan, Russell and myself have been further characterized. Additional complementation tests indicate that RS2 and RS7 belong to the same group as DD79, that DD72 and DD75 complement with all other groups including one another. RS3 and DD76 remain unclassified. Sixteen of these strains have been tested for their chemotactic responses in 11 different tests. The six strains belonging to the complementation group of DD79 have similar patterns of responsiveness. This pattern is a nearly normal response to C02 in pH 6.0 phosphate buffer, to acid, and to pyridine and little if any response to Na+, Cl- , OH-, CO2 in pH 8.8 borate, cAMP, and D-tryptophan. A particularly interesting observation is that three other strains (representing at least two different complementation groups) avoid cyclic AMP instead of being attracted. All but two of the 16 strains had substantial responses to C02 in phosphate and to acid. Most strains were defective in most other tests. Recently I tested two of Don Riddle's dauer-defective mutants (E1378 and E1382) they also demonstrated relatively normal responses to C02 in phosphate and to acid. This observation prompted me to test the Caltech chemotaxis mutants for defective dauer production. Initial results indicate that RS4 and DD71 do not make dauer larvae in normal numbers and that DD73 makes dauers even in the presence of bacteria. Thus it looks like lack of chemotaxis to NaCl and defective dauer production select for much the same kind of mutants. I hope to collect a much different set of mutants by selecting for those defective in avoidance of acid or C02 in phosphate. We have recently discovered that the worm avoids mM concentrations of glucose, fructose, and mannose. Experiments to further define the specificity are in progress. Questions: 1. Does anyone have suggestions as to the possible adaptive significance of the chemotactic responses such as attraction to ions or pyridine and avoidance of D-tryptophan or certain hexoses? 2. Is anyone presently working on the identification of 'natural' chemical stimuli such as those in bacterial cultures?