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Variability and equifinality in the early morphogenesis of the marine hydroid, Dynamena pumilaстатья
Дата последнего поиска статьи во внешних источниках: 28 мая 2015 г.
- Авторы: Kraus Yu A., Cherdantsev V.G.
- Журнал: Russian Journal of Developmental Biology
- Том: 30
- Номер: 2
- Год издания: 1999
- Издательство: Springer Verlag
- Местоположение издательства: Germany
- Первая страница: 118
- Последняя страница: 129
- Аннотация: Embryonic development of a marine hydroid Dynamena pumila was studied using in vivo observations, histology and scanning electron microscopy technique. Analysis of morphological variability (MV) revealed that “variable” developmental stages characterized by the high level of MV alternate with the “nodal” stages characterized by the relatively low level of MV. The MV level at the early cleavage stage is extremely high. At the each following stage MV level depends on the spatial scale of morphogenetic factors arising and acting at this stage. These factors are: passive interactions among the neighboring embryos at the morula stage; cooperative epithelization of cells during the formation of local fragments of superficial epithelial sheet; a feedback between the pattern of mechanical stresses of an embryonic surface, direction of cell movements and embryonic shape. It was shown that planar intercalation of superficial cells plays a key role in the formation of an integral superficial epithelial sheet, ordering of an embryonic shape and differentiation of AP axis. The P-half of a planula is marked by a region in which, for any arbitrary reasons, the closure of an epithelial sheet is delayed. This region does not coincide with the posterior pole of a planula. So, from the morphological point of view, the Dynamena planula has a bilateral symmetry. The general conclusion is that the level of MV gradually decrease during Dynamena early development due to an increase in the spatial scale of cellular (and supercellular) interactions and reduction in the symmetry order of developing system.
- Добавил в систему: Краус Юлия Александровна