. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 214 G. DESSEV AND R. GOLDMAN 100 45K — 29K — Figure 4. SDS PAGE of isolated VE in ')!. gel. The positions of the molecular weight markers are shown. oocyte activation on calcium, using hypertonic solutions (Allen, 1953) such as M glycerol and M NaCl as activating agents. The rationale for these experiments was the initial events that induce the oo- cytes to resume maturation are believed to involve cell depolarization caused by changes in permeability (Fin- kel and Wolf, 1978;Jaffe, 1983, 1985). Our
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 214 G. DESSEV AND R. GOLDMAN 100 45K — 29K — Figure 4. SDS PAGE of isolated VE in ')!. gel. The positions of the molecular weight markers are shown. oocyte activation on calcium, using hypertonic solutions (Allen, 1953) such as M glycerol and M NaCl as activating agents. The rationale for these experiments was the initial events that induce the oo- cytes to resume maturation are believed to involve cell depolarization caused by changes in permeability (Fin- kel and Wolf, 1978;Jaffe, 1983, 1985). Our experiments suggested that calcium, by interacting with the oocyte surface, maintains the latter in a structural state neces- sary for these events to occur. We hypothesized that un- physiological treatments, such as osmotic shock, might disturb the permeability barrier at the oocyte surface and lead to depolarization and activation in the absence of calcium. Furthermore, glycerol, known to "soften" the VE (Rebhun and Sharpless, 1964), might be expected to 90 - 80 - 70 • 60 • 50 - 40 - 30 - 20 - 10 - 001 Ca2+CONCENTRATION (mM) Figure 6. Binding of 45Ca-+ to isolated VE was determined under the same conditions as in Figure 5, but at Ca2+ concentrations up to 40 mM. counteract the EGTA-induced stabilization which was thought to prevent the oocyte activation. We found that the oocytes could be activated in CFSW containing glycerol and 50 mM KG. The proportion of activated oocytes did not change linearly with glycerol concentration, but increased abruptly around 10% ( M) glycerol, suggesting a correlation between activation and hypertonicity (Fig. 8). No activation occurred in CFSW and 50 mM KC1 alone. Activation (30-50%) was also observed in solutions containing M glycerol, 20 mM Na-phosphate (pH ), 50 mM KC1, and 30-80 mM EGTA (not shown). In another series of experiments, we used a procedure involving concentrated solutions of NaCl to activate the cel
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
