title: [R1 cell and musculature of Filariae; ultrastructural analysis (author's transl)].
abstract: Ultrastructural study of ontogenesis of a filaria, Dipetalonema (M.) dessetea, confirms Bain's (1970) hypothesis, following which the R1 cell plays a role in the elaboration of the musculature of the adult filaria. Anatomical observations related to the hypodermis and musculature of the larva (distribution of the cells, nature of their junctions, presence of intermediate cells between embryonic cells derived from R1 cell and muscle cells) show that the cells derived from R1, which form four longitudinal files, produced successively, from 5th to 13th day, about ten files of muscle cells in each submedian field. The primary musculature of the microfilaria, which corresponds to a single file of muscular cells in each field, is not ectodermic, as supposed before, but mesenchimatic. At the vicinity of R1 daughter cells, this musculature is slightly dedifferenciated (about 5 files of myofilaments instead of 10-20 in the microfilaria and the L3); then its evolution becomes identical to this of new formed muscle cells. The presence as well as the evolution of the R1 cell seem to be identical in every totally heteroxenous Phasmidian Nematodes; both suggest analogy with the imaginal discs of the holometabolic Insects.
mesh_terms: D000818:Animals; D002455:Cell Division; D004153:Dipetalonema / Q000166:cytology / Q000196:embryology / Q000648:ultrastructure*; D008854:Microscopy, Electron; D009132:Muscles / Q000166:cytology / Q000196:embryology
vernacular_title: Cellule R1 et musculature des Filaires; analyse ultrastructurale.