Worm Breeder's Gazette 8(1): 25
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 a laser microbeam to study the location of the sense organs used in C. elegans chemotaxis to various chemicals. Electron microscopy has demonstrated that there are two types of likely chemoreceptors. These are the two amphids, one of which is found on each of the lateral lips, and the inner labial sensilla, one of which is located on each of the 6 lips. We do not attempt to selectively destroy the two sensilla located on a lateral lip, but rather damage both lateral lips with the objective of eliminating both amphids but only one-third of the inner labial sensilla. When this is done and the nematodes are tested for response to various chemical stimuli, no change in response to Na+, D-tryptophan, C02 (pH6, phosphate buffer) or high (osmotic) NaCl is found. The only exception to this pattern is that the response to cAMP was weakened or eliminated. When all six lips were targeted, the response to Na+ weakened and even reversed in sign. We conclude that the amphids are not the only chemoreceptor mediating responses to these chemicals, with the exception of cAMP. It is suspected that the amphids detect stimuli that have not yet been tested. The reversed response after all lips have been targeted is not understood and most of the rest lack one. As expected, the HSNs are restored and the egg-laying defect of tra-2(n1106) is largely suppressed by ced-3, whereas other phenotypic indications of maleness are not.