Worm Breeder's Gazette 5(1): 19
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.
Halfway along each posterior excretory canal is a small cell, probably secretory in function, that sends processes anteriorly and posteriorly along the canal: [See Figure 1] Laser ablation of these cells in young L1's has an unexpectedly dramatic effect: the animals take on a starved appearance, and die before becoming adult. Although the excretory canals are interrupted at the site of ablation, and consequently their posterior sections disappear, they can be seen to regenerate in the course of the next 24 hours. In any case, it is known that individuals in which the excretory system has been destroyed are capable of becoming adults ( Singh and Sulston, Nematologica, 24, 63-71,1978). Similarly, the other adjacent cells (V3, P5/6, hsn) can be ablated without killing the animal. Therefore, it appears that the canal associated cells are essential to the survival of C. elegans.The mutant vab-87 (E1017) matures into an adult whose anterior half appears normal but whose posterior half is thin, pale and uncoordinated. Nomarski examination shows that all the tissues of the posterior half look starved; the canal associated cells are displaced into the head, and sometimes one of them seems to be missing. These cells are difficult to distinguish from neurons in L1's, but in older larvae they enlarge and can be recognized. One animal was found whose posterior half was of normal size; subsequent Nomarski examination showed that one of the canal associated cells was in the wild type position. Although various other cells are displaced in E1017, these observations suggest that its principal character results from the abnormal position of the canal associated cells.