Worm Breeder's Gazette 3(2): 19a
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 just completed an EM study of L1 and L2 gonads in hermaphrodite and male worms. Worms were sexed by the presence or absence of the enlarged B cell in the tail before sectioning. Sexing was confirmed by coelomocyte position around the young gonad after sectioning. The major purpose of this study was to see the cytoplasmic boundaries of the gonadal somatic progenitor cells (Z1 and Z4) and their descendants. (The cells in the gonadal primordium are Z1, Z2, Z3, and Z4 from anterior to posterior. Z2 and Z3 are the germ line progenitor cells.) Two findings seem particularly interesting to us. 1) The morphology of young gonads, before Z1 and Z4 divide, is the same in hermaphrodites and males. Z1 possesses a thin cytoplasmic process that extends posteriorly, and Z4 possesses one that extends anteriorly along the ventral surface of the gonad. These processes make contact mid-ventrally. No syncytial interconnection was observed in serial sections of the region where the processes meet. No special junctions were observed between the processes. 2) The somatic cells that occupy the tip positions of the elongating gonadal arms (Z1.aa leads the anterior hermaphrodite arm and Z4.pp leads the posterior hermaphrodite arm; Z1.paa or Z4.aaa leads the single arm in males) have a common ultrastructure. These cells, and only these cells, exhibit distended cisternae of rough ER and an extensive Golgi apparatus. All the other somatic and germ line cells are packed with free ribosomes and mitochondria.