Russell L D, Peterson R N, Blumershine R, Freund M
Scan Electron Microsc. 1980(3):407-12.
Scanning electron microscopy demonstrated that freshly ejaculated boar sperm bind in large numbers to the cumulus-free zona pellucida of porcine oocytes. Sperm were bound head-first although some portions of the flagellum occasionally made contact with the zona. Scanning microscopy also showed that sperm did not undergo an acrosome reaction or penetrate the zona after binding. Binding of boar sperm was visibly inhibited by pretreatment of the sperm by Fab antibodies to boar sperm plasma membranes. The forgoing indicate that specific receptors for the zona pellucida are present and exposed on the surface of non-capacitated boar sperm. In addition, when soluble components which were extracted from sperm by sedimentation at high speed, were preincubated with oocytes, sperm did not bind. Minor surface changes were noted after these treatments, but the zona remained intact and was not penetrated by sperm. Either this treatment inactivated sperm receptors or the outer layer of the zona, which may be the only portion of the zona containing receptors, was removed. Since binding of the sperm to the zona pellucida involved the sperm plasma membrane, we suggest that this membrane is intact when the sperm reaches the zona. Surface changes accompanying capacitation are apparently not necessary for species-specific sperm-egg binding in vitro in the pig.
扫描电子显微镜显示，刚射出的公猪精子大量结合到猪卵母细胞无卵丘的透明带上。精子以头部先着附，尽管鞭毛的某些部分偶尔会与透明带接触。扫描显微镜还显示，精子在结合后并未发生顶体反应或穿透透明带。用抗公猪精子质膜的Fab抗体预处理精子，可明显抑制公猪精子的结合。上述结果表明，透明带的特异性受体存在于未获能的公猪精子表面并暴露在外。此外，当用高速离心从精子中提取的可溶性成分与卵母细胞预孵育时，精子不发生结合。这些处理后观察到精子表面有微小变化，但透明带保持完整，精子未穿透。这种处理要么使精子受体失活，要么去除了透明带的外层，而外层可能是透明带中唯一含有受体的部分。由于精子与透明带的结合涉及精子质膜，我们认为精子到达透明带时质膜是完整的。在猪的体外，伴随获能的表面变化显然不是物种特异性精卵结合所必需的。
