Worm Breeder's Gazette 11(4): 114
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.
As described in WBG 10(3), we have microinjected Lucifer Yellow(LY) into the embryo of C. elegans as a marker for dye coupling. Meanwhile we have extended our studies to other free-living nematodes. In C. elegans LY quickly distributes all over the early embryo. If fluorescently labeled Dextrane is injected, it always remains in the marked cell and its progeny, indicating that the observed dye-coupling is not due to cytoplasmic bridges. Only after the formation of P4 ( primordial germ cell), this cell and its sister temporarily form a dye- coupling compartment by their own. But just P4 and its daughters Z2 and Z3 remain permanently discoupled while D joins again the one large dye-coupling compartment comprising all somatic cells. If LY is injected into P4 it remains restricted to this cell and its descendants. In two other species Rhabditis dolichura and Cephalobus spec. which develop considerably slower, we found in the early embryo similar pattern of dye-coupling as in C. elegans. However, here passage of the injected tracer appears to take place only luring a distinct phase of the cell cycle, i.e. during interphase. In C. elegans the phase of complete coupling of somatic cells extends into late proliferation. Although we have some problems with injecting into small blastomeres, preliminary data indicate that during early morphogenesis tissue-specific compartments form. In Cephalobus this restriction in dye-coupling leading to the establishment of several distinct communication compartments appears to occur considerably earlier. Presently we test the idea that the pattern of dye-coupling is more correlated to absolute time of development rather than to the cell stage reached. This assumption is supported by our finding that in slower developing nematodes we have studied the typical autofluorescence appears visibly earlier in the gut lineage than in C. elegans.