Acrosome reaction of fowl sperm: evidence for shedding of the acrosomal cap in intact form to release acrosomal enzyme.
Acrosome reaction of fowl sperm: evidence for shedding of the acrosomal cap in intact form to release acrosomal enzyme.
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DOI：
10.3382/ps.2012-02523
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发表时间：
2013-03
期刊：
影响因子：
4.4
通讯作者：
M. U. Ahammad;C. Nishino;H. Tatemoto;Nobuhiko Okura;S. Okamoto;Yasuhiro Kawamoto;T. Nakada
中科院分区：
文献类型：
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作者：
M. U. Ahammad;C. Nishino;H. Tatemoto;Nobuhiko Okura;S. Okamoto;Yasuhiro Kawamoto;T. Nakada
本研究的目的是确定鸡精子顶体反应（AR）过程中顶体酶的释放位点和顶体帽的命运。带晕的明胶底物盖片经过扫描电子显微镜来确定顶体蛋白水解酶释放的位置，从而在单个精子的顶体周围形成晕。采用异硫氰酸荧光素标记花生凝集素荧光染色和扫描电镜分别对含有5 mmol氯化钙(2)的溶解性卵泡内周层（IPL）处理的等分精子进行AR和顶体区域状态的检测。在光晕内，一层无明胶（蛋白水解的明胶）在精子顶体周围延伸了一段距离。所有在明胶上显示光圈形成的精子在顶体帽基部的顶体亚棒周围有一个单一的圆形开放。精子与溶解的IPL在5mmol CaCl(2)的存在下相互作用导致41.4±1.8%的精子发生AR，通过异硫氰酸荧光素标记的花生凝集素进行了评估。同样，通过扫描电镜观察，用溶解IPL加5mmol氯化钙(2)处理的精子中，38.2±2.3%暴露顶体下棒。在所有精子检查中，顶体顶端区域没有发现顶体膜破坏的迹象。相反，发现顶体帽完整地从精子的顶体区域分离，表明鸡精子的AR导致顶体帽完整地去除。基于这些实验观察，我们认为鸡精子的AR过程是独特的；顶体蛋白水解酶的释放可通过顶体帽基部形成的单个圆形开口发生，顶体帽以完整的形式从精子的后顶体区域分离。
The aim of this study was to determine the site of enzyme release from the acrosome and the fate of the acrosomal cap during the process of acrosome reaction (AR) in fowl sperm. Gelatin substrate coverslips with halos were subjected to scanning electron microscopy to determine the site from which acrosomal proteolytic enzyme was released to form a halo around the acrosome of individual sperm. Aliquots of sperm treated with solubilized inner perivitelline layer (IPL) containing 5 mmol CaCl(2) were simultaneously subjected to fluorescent staining with fluorescein isothiocyanate-labeled peanut agglutinin and scanning electron microscopy to evaluate AR of sperm and to examine the status of the acrosomal region, respectively. Inside the halos, a gelatin-free (proteolyzed gelatin) layer was found extending some distance around the acrosome of sperm. All of the sperm showing the formation of halos on gelatin had a single circular opening around their subacrosomal rod at the base of the acrosomal cap. Interaction of sperm with solubilized IPL in the presence of 5 mmol CaCl(2) resulted in 41.4 ± 1.8% of the sperm to undergo AR, as evaluated by fluorescein isothiocyanate-labeled peanut agglutinin. Similarly, as observed using scanning electron microscopy, 38.2 ± 2.3% of the sperm treated with solubilized IPL plus 5 mmol CaCl(2) had exposed subacrosomal rod. In all sperm examined, no sign of disruption of the acrosomal membrane was found in the apical region of the acrosome. Rather, the acrosomal caps were found intact detached from the acrosomal region of the sperm, indicating that AR of fowl sperm resulted in the intact removal of the acrosomal cap. Based on these experimental observations, we suggest that the process of AR in fowl sperm is unique; the release of the acrosomal proteolytic enzyme may occur through a single circular opening formed at the base of the acrosomal cap and the acrosomal cap is detached in intact form from the posterior acrosomal region of the sperm.