Movement of an Epithelial Layer Isolated from Early Embryos of the Newt, Cynops pyrrhogaster I. Development of Folding Movement of the Blastocoelic Wall Isolated from Embryos before and during Gastrulation: (blastocoelic wall/folding movement/submembranous microfilaments layer/amphibian embryos).

The blastocoelic wall (BW) was isolated from embryos of the newt, Cynops pyrrhogaster, before and during gastrulation. The mechanism responsible for the folding movement of the isolated BW toward the basal side was investigated. The BW isolated from the early gastrula was induced to fold toward the basal side by treatment with serum. The folding movement of the isolated BW took place from the late blastula to early gastrula stage. Electron microscopy, rhodamine-phalloidin staining and experiments with inhibitors show that the development of the folding movement was correlated with the appearance of a submembranous microfilaments layer (SML) which was formed beneath the cell membrane on the basal side of the BW and suggest that the contraction of actin filaments in the SML is involved in the folding movement of the isolated BW toward the basal side.