透明带处精卵相互作用的机制。
Mechanics of sperm-egg interaction at the zona pellucida.
作者信息
Baltz J M, Katz D F, Cone R A
机构信息
Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218.
出版信息
Biophys J. 1988 Oct;54(4):643-54. doi: 10.1016/S0006-3495(88)83000-5.
Mammalian sperm traverse several layers of egg vestments before fertilization can occur. The innermost vestment, the zona pellucida, is a glycoprotein shell, which captures and tethers the sperm before they penetrate it. We report here direct measurements of the force required to tether a motile human sperm as well as independent calculations of this force using flagellar beat parameters observed for sperm of several species on their homologous zonae. We have compared these sperm-generated forces with the calculated tensile strength of sperm-zona bonds, and found that a motile sperm can be tethered, at least temporarily, by a single bond. Therefore, sperm can be captured by the first bond formed and tethered permanently by a few. The sperm cannot subsequently penetrate the zona unless the bonds are first eliminated. However, premature elimination would simply allow the sperm to escape. Therefore, not only must the bonds be eliminated, but the timing of this must be regulated so that the sperm is already oriented toward the egg and beginning to penetrate as the bonds are broken.
在受精发生之前，哺乳动物的精子要穿过卵的多层附属结构。最内层的附属结构——透明带，是一层糖蛋白外壳，在精子穿透它之前，它会捕获并束缚精子。我们在此报告了直接测量束缚活动中的人类精子所需的力，以及利用在几种物种的精子与同源透明带结合时观察到的鞭毛摆动参数对该力进行的独立计算。我们将这些精子产生的力与计算得出的精子 - 透明带结合的抗张强度进行了比较，发现一个活动中的精子至少可以被单个结合暂时束缚。因此，精子可以被形成的第一个结合捕获，并被少数几个结合永久束缚。除非这些结合首先被消除，否则精子随后无法穿透透明带。然而，过早消除结合只会让精子逃脱。因此，不仅必须消除结合，而且必须对消除的时机进行调节，以便在结合断裂时精子已经朝向卵子并开始穿透。
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