Newly identified 'wanderer' cells in the dicyemid mesozoan Kantharella antarctica: a new mode of reproduction?
In the nematogen of the dicyemid mesozoan Kantharella antarctica two types of germinal cells are present which differ in size and composition of their organelles: the voluminous type A germinal cells, with high amounts of glycogen, small vesicles and a cortically arranged cytoskeleton, which differentiate into migratory 'wanderer' cells and the small type B germinal cells, with polarly arranged bundles of microtubules, which develop asexually into vermiform embryos. Type A germinal cell, however, becomes polarized during its differentiation, whereby the nucleus and all remaining organelles concentrate at one pole and the cytoskeleton organizes into a pseudopod at the other. Now called 'wanderer' cell, it leaves the nematogen by opening the junctions along the contact zones of neighbouring cells using this intercellular space like an excretory duct. This polarized migratory cell exhibits conspicuous morphological features that are similar to mature sperm of nematodes, whereby the characteristics of the cytoskeleton resemble that of amoeboid Protozoa.
Czaker
R
R
Institute of Histology and Embryology, University of Vienna, Austria. renate.czaker@univie.ac.at
D000818:Animals; D000864:Antarctic Regions; D002465:Cell Movement / Q000502:physiology; D005260:Female; D005854:Germ Cells / Q000502:physiology* / Q000648:ultrastructure; D007365:Intercellular Junctions / Q000502:physiology / Q000648:ultrastructure; D007448:Invertebrates / Q000166:cytology / Q000502:physiology*; D008297:Male; D009024:Morphogenesis; D010312:Parthenogenesis / Q000502:physiology; D012098:Reproduction / Q000502:physiology*