Cell adhesion and the negative cell surface charges in embryonic cells of the starfish Asterina pectinifera

Abstract

Spherical blastomeres of starfish embryos begin to adhere to neighboring blastomeres and to become columnar in shape from the 7(th) or 8(th) cleavage onward. Studying development of embryos in the presence of LiCl, we found that developmental changes in cell-cell contacts were accelerated by LiCl. In order to learn why LiCl increased the adhesiveness between blastomeres, the negative surface charge density was estimated by the method of cell electrophoresis. It turned out that the electrophoretic mobility (EPM) of all blastomeres isolated from LiCl-treated embryos before the 512-cell stage was remarkably decreased. At the mid-gastrula stage, however, when constituent cells were connected with each other more tightly, the EPM was significantly retarded irrespectively whether the cells had been isolated from control or from LiCl-treated embryos. From these results of cell electrophoresis we conclude that reduction of the negative surface charge density may be one of the important factors that enhance the adhesion of starfish embryonic cells.

Plasma membrane surface potential (ψpm) as a determinant of ion bioavailability: A critical analysis of new and published toxicological studies and a simplified method for the computation of plant ψpm

“…Some ions can be lumped together if they have similar charges and binding strengths (as do most monovalent cations other than H ϩ ), and ions at very small concentrations can be ignored, but micromolar concentrations of Al 3ϩ and La 3ϩ cannot be ignored. Upon speciation, PM can be computed by inserting free ion activities into Equation 11. This computation is much simpler than the iterative techniques required to solve the several equations of the G-C-S model.…”

“…This computation is much simpler than the iterative techniques required to solve the several equations of the G-C-S model. The success of this simpler method of computation will be judged by the similarity of values for PM computed by Equation 11 and by the G-C-S model.…”

“…M3ϩ H In Equation 11, the second coefficient, Ϫ32.2, pertains when activities are expressed in molar units (M), but it can be changed to Ϫ92.5 for millimolar (mM) activities and to Ϫ266 for micromolar (M) activities; it is also necessary to change the coefficient of , 3,230,000, to 102 for millimolar 2 a H activities and 0.00323 for micromolar activities. In the equation, several monovalent cations, including Na ϩ , K ϩ , , and ϩ NH 4 others, are added together, and several divalent cations, including Ca 2ϩ , Mg 2ϩ , Sr 2ϩ , and others, are added together too.…”

Relation of Nodal expression to the specification of the dorsal‐ventral axis and tissue patterning in the starfish Patiria pectinifera

“…Both genes were expressed soon after bastomeres came in close contact (Figs A,B and A,B; Dan‐sohkawa & Satoh ; Masui et al . ). The levels of the PpNodal and PpBmp2/4 mRNAs peaked at 16 and 18 h, respectively, (Figs A,B and A,B).…”

The Surface Potential Variation of Neural Stem/Progenitor Cells during Differentiation Process

“…The electrophoresis of single cells is measured under a microscope. Cell surface electric charges and electrophoretic mobility between various cell types, including cells of the immune system [8], pathological cells [9,10], and cell differentiation [11][12][13]. Cell surface properties can be analyzed by measurable changes in the electrokinetic potential, and changes in their electrophoretic mobilities .…”