Worm Breeder's Gazette 5(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.
Ultrastructural study of L2 larvae of the non-chemotactic, dauer- defective mutant E1379 have shown that the morphology of amphid and phasmid cilia are both severely affected in this mutant. The cilia are enlarged, irregular in shape and filled with an electron-dense matrix. Microtubules are generally absent from the afferent endings of the neurons, while the basal bodies appear normal. The morphology of E1379 phasmid neurons closely resembles that of the amphids although phasmid microtubules were less severely affected in a second specimen. The amphid morphology of this strain is similar to that exhibited by the che-3 mutant, E1124, studied by Lewis and Hodgkin (J. Comp. Neurol. 172: 489-510, 1977). Both mutations are on LGI. In addition to being dauer-defective and nonchemotactic, E1379 males do not mate successfully although they do contain sperm, and they attempt to copulate. This behavior could be related to chemosensory impairment. The phasmids in the male may respond to a substance released through the hermaphrodite vulva, and this response may be an essential step in successful mating. The fact that a single mutation causes similar amphid and phasmid defects supports the idea suggested by Sam Ward that these structurally similar sense organs share common developmental steps.