Cell proliferation and early differentiation during embryonic development and metamorphosis of Hydractinia echinata.

摘要: The early embryonic development of Hydractinia lasts about 2.5 days until the developing planula larva acquires competence for metamorphosis. Most cells stop cycling on reaching larval stage. In older larvae Hydractinia, that are still proliferating occur exclusively in endoderm a typical distribution along longitudinal axis. During metamorphosis, proliferation activity begins again. number S-phase has increased by 9th hour after induction Proliferative starts middle gastric region and basal parts primary polyps. Tentacles stolon tips always free replicating cells.