title: Stem cell dynamics during growth, feeding, and starvation in the basal flatworm Macrostomum sp. (Platyhelminthes).
abstract: Development, growth, and regeneration in Macrostomum are based--as in all Platyhelminthes--on likely totipotent stem cells (neoblasts), basic for all Bilaterians. We demonstrate dynamics and migration of neoblasts during postembryonic development, starvation, and feeding of Macrostomum sp. Double labeling of S-phase and mitotic cells revealed a fast cell turnover. Conflicting with recent results from planarians, we have some indication of slow cycling neoblasts. As in planarians, starvation dramatically reduced mitotic activity and a very basic level was maintained after 30 days of starvation. Afterward, feeding induced a dramatic immediate proliferative response probably caused by G2-arrested neoblasts. The following 12 hr showed a significant mitotic decline, caused by the depletion of the G2 neoblast pool. Neoblasts that pass through S-phase led to a maximum of mitoses after 48 hr. Our results allow deeper insight into cellular dynamics of an ancestral bilaterian stem cell system of a basal Platyhelminth.
authors.affiliation: Division of Ultrastructure Research and Developmental Biology, Department of Zoology and Limnology, University Innsbruck, Innsbruck, Austria.
authors.forename: Katharina T
authors.initials: KT
authors.lastname: Nimeth
authors.forename: Monika
authors.initials: M
authors.lastname: Mahlknecht
authors.forename: Andrea
authors.initials: A
authors.lastname: Mezzanato
authors.forename: Roland
authors.initials: R
authors.lastname: Peter
authors.forename: Reinhard
authors.initials: R
authors.lastname: Rieger
authors.forename: Peter
authors.initials: P
authors.lastname: Ladurner
mesh_terms: D000818:Animals; D000963:Antimetabolites / Q000494:pharmacology; D001973:Bromodeoxyuridine / Q000494:pharmacology; D002453:Cell Cycle; D002455:Cell Division; D004396:Coloring Agents / Q000494:pharmacology; D005508:Food Deprivation; D016195:G2 Phase; D006657:Histones / Q000378:metabolism; D006918:Hydroxyurea / Q000494:pharmacology; D018613:Microscopy, Confocal; D008938:Mitosis; D010986:Platyhelminths; D016196:S Phase; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism*; D013997:Time Factors
chemical_list: D000963:Antimetabolites; D004396:Coloring Agents; D006657:Histones; D001973:Bromodeoxyuridine; D006918:Hydroxyurea