Marina Dan-Sohkawa

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Not only a whole denuded egg, but also blastomeres isolated from 2-, 4- and 8-cell starfish embryos developed into morphologically normal, but dwarf bipinnariae, the sizes of which were roughly proportionate to that of the respective original blastomeres. Some of the blastomeres isolated from the 16-cell stage were also capable of developing into the larval(More)
A process of cell division in the blastular wall of the starfish, Asterina pectinifera, was observed, and an attempt was made to model with a computer simulation the way in which cell number increases in such a tissue. Dividing cells at stages between the 2(11)-cell and the beginning of rotation were observed to shift these positions to the outer surface of(More)
Cells dissociated from swimming embryos of the starfish are able to reconstruct bipinnaria larvae. This process consists of reaggregation (stage 1), formation of the external epithelium (stage 2), development of the internal cavities which will eventually grow either into the blastocoel or the intestinal lumen (stage 3), gastrulation or fusion of the(More)
A starfish egg, denuded of the fertilization membrane and placed on a glass surface, becomes a cell monolayer after several cleavages. This sheet of cells folds and forms a hollow sphere resembling a normal blastula at the 2(9)-2(10)-cell stage ('closing movement'). A marked morphological change was observed in each cell, preceding the closing movement. The(More)
Coelomocytes (blood cells) of the solitary ascidian Halocynthia roretzi were placed in culture to which sheep red blood cells (SRBCs) were introduced. Their reactions against SRBCs were observed by phase-contrast, time-lapse video and scanning electron microscopy. Three cell types, the phago-amoebocyte, the vacuolated cell and the fusogenic phagocyte,(More)
The morphogenetic processes of coelomic pouch (CP) formation in starfish embryos that were experimentally dissociated and induced to undergo reconstruction were studied. An analysis of these embryos randomly chosen from several cultures showed that CP always form on either side of the esophagus, even though the CP formation can differ in timing of(More)
Here we characterize starfish larval mesenchyme cells, in terms of not only their phagocytic behavior, but also their structural and functional properties as a defense system. Our study reveals the following: (1) most mesenchyme cells construct a dynamic network structure beneath the body wall; (2) mesenchyme cells phagocytically respond to almost all(More)
By using a monoclonal antibody (4H11 Mab), we have investigated morphogenetic functions of a fibrous component of the blastocoelic extracellular matrix in relation to cellular activities during early development of the starfish Asterina pectinifera. The 4H11 fibers fill the blastocoele from the late-cleavage to late-gastrula stage and contain the 370-kDa(More)