Worm Breeder's Gazette 2(2): 10b

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.

Some Observations on Moulting

R.N. Singh, J.E. Sulston

Before each moult, the seam cells (i.e.  the lateral hypodermal stem 
cells, together with an extra cell anteriorly) take on a 
characteristic granular appearance in Nomarski optics.  Electron 
microscopy reveals large Golgi bodies in the seam cells at these times.
Presumably this means that the lateral cuticle is specialized in 
some way (maybe mechanically).
The seam is required for ala formation.  When groups of seam cells 
are destroyed by the laser microbeam in the L3 or young L4, 
corresponding gaps appear in the adult alae.  E1348 (lin-5 II) and 
E1466 (lin-6 I) both have defective seams; both have defective alae as 
dauers and usually none as adults.
Regions without a seam fail to undergo the diametric shrinkage-
normally characteristic of dauer maturation.  Thus dauer larvae of 
E1348 and E1466 have a lumpy appearance.  They are also less resistant 
to SDS than N2 dauers.
Laser experiments indicate that the excretory system is not 
essential for moulting.  The g1 pharyngeal glands are very active just 
before ecdysis; their secretions may well be necessary to weaken the 
head cuticle.