. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. Figure 6. Fleetron mierographs of sperm binding to the isolated chorion. One minute after insemination. • (a) A spermatozoon adhering to the outer surface of chorion with the spread acrosomal pro- cess (AP) in artificial ordinary seawater. (h) A spermatozoon attached to the outer surface of the chorion without acrosome reaction in artifi- cial Ca-free seawater. AV: Acrosomal vesicle. sperm bound to the isolated chorion did not undergo the acrosome reaction (Table I. Fig. 6b). The outer acroso- mal membrane of sperm h
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. Figure 6. Fleetron mierographs of sperm binding to the isolated chorion. One minute after insemination. • (a) A spermatozoon adhering to the outer surface of chorion with the spread acrosomal pro- cess (AP) in artificial ordinary seawater. (h) A spermatozoon attached to the outer surface of the chorion without acrosome reaction in artifi- cial Ca-free seawater. AV: Acrosomal vesicle. sperm bound to the isolated chorion did not undergo the acrosome reaction (Table I. Fig. 6b). The outer acroso- mal membrane of sperm head-tip was attached to the chorion surface. No spermatozoon was bound to the in- ner surface of the chorion (the fourth layer) in both ordi- nary and Ca-free seawater. Effect ofpronase treatment of eggs on sperm-egg binding We tried to remove the egg-surface component that binds sperm and induces the acrosome reaction. Unfer- tilized eggs were pretreated with pronase and then fixed. After rinsing, the eggs were inseminated in 30% seawater. Sperm attachment was blocked or greatly reduced (Table II, Fig. 7). The pronase-treated eggs were examined by electron mi- croscopy. The first and the second layers were removed from the chorion in the pronase-treated eggs (Fig. 8). The outer surface of the chorion did not stain with PTA. Acrosome reaction-inducing activity in chorion extract Chorion extracts were prepared by soaking chorions in DW. Sperm were added to the chorion extract diluted with natural seawater. Many of the free swimming sperm underwent acrosome reaction (Fig. 9, Table III). The sperm did not undergo acrosome reactions in control media (30% seawater). After isolated chorions were treated with DW, they were mixed with sperm in 30% seawater. Few sperm were bound to the chorions (Fig. 10). These chorions were ex- amined by electron microscopy. The PTA-positive layer at the outer surface of the chorions became thinner after the DW-treatment (Fig. 11). No morphological c
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
