CHARACTERIZATION OF SPERM MEMBRANES

精子在通过附睾的过程中，获得了 通过体外受精试验评估受精卵。 而 很明显，许多精子特征的改变可能是重要的， 从使用许多物种的各种研究来看， 代表了一个本质的变化 许多关于变化的报道 精子进行顶体反应和卵子结合的能力， 一个例子。 该实验室为促进 通过引入新的物理特性来量化膜特征的变化 评估膜状态的方法，并完成对 覆盖在顶体上的质膜的脂质成分。 这些 公布的数据，加上初步数据，结合新推出的 关于脂质组成与 膜稳定性，以产生关于分子的独特假设 精子获得能力所必需的事件， 附睾成熟和射精，进行顶体反应。 用于检验的假设如下： 对于获得顶体的能力至关重要 反应 精子被认为是一个被动的角色， 膜修饰，因为它们的表面的改变是由 与特定脂蛋白供体和脂质交换蛋白的相互作用 在他们周围的液体中发现的。 转让的特殊性是这样的 我们测量到的去除一摩尔 磷脂酰乙醇胺和一摩尔磷脂酰胆碱的插入 再加上覆盖在细胞膜上的三摩尔胆固醇 顶体导致质膜的内半部分“受压”， 双层。 这种应力的释放，在沉积后由未知因素引起， 雌性生殖道，导致顶体反应。 为了验证这一假设，概述了五个项目。 第一个将 比较体外诱导的顶体反应的多种测定。 的 第二个和第三个将产生足以表征脂质的数据 交换蛋白和脂蛋白。 的 第四个项目将建立必要的方法， 精子膜组成的体外（模拟原位变化），而 期末专题将提供一个已知的变化的影响的摘要测试， 脂质成分对未成熟附睾精子接受精子的能力的影响 体外诱导的顶体反应。

Sperm, during transit through the epididymis, acquire the capacity to fertilize ova as assessed via in vitro fertilization assays. While alterations in many spermatozoal features may be important, it is clear from a variety of studies using many species that modification of membranes represents one essential change. The many reports of changes in the ability of sperm to undergo the acrosome reaction and ova binding serves as one example. This laboratory has made major contributions to the quantification of changes in membrane features by introducing new physical methods to assess membrane status and completing the first analysis of the lipid components of the plasma membrane overlying the acrosome. These published data, plus preliminary data, are combined with newly introduced concepts regarding the specific relationship of lipid composition on membrane stability to yield a unique hypothesis regarding the molecular events that are necessary for sperm to acquire the capacity, during epididymal maturation and ejaculation, to undergo the acrosome reaction. The hypothesis presented for test is as follows: Lipid modification is essential to the acquisition of the capacity to undergo the acrosome reaction. Sperm are viewed as serving in a passive role with regard to membrane modifications, in that alteration of their surfaces results from interaction with specific lipoprotein donors and lipid exchange proteins found in their surrounding fluids. The specificity of the transfer is such that the our measured changes of removal of one mole of phosphatidylethanolamine and insertion of one mole of phosphatidylcholine plus three moles of cholesterol in the plasma membrane overlying the acrosome results in a "stressed" inner half of the plasma membrane bilayer. Release of this stress, by unknown factors after deposition in the female tract, results in the acrosome reaction. To test this hypothesis, five projects are outlined. The first will compare multiple assays of the in vitro induced acrosome reaction. The second and third will yield data sufficient to characterize the lipid exchange proteins and lipoproteins of male reproductive tract fluids. The fourth project will establish methods necessary to systematically alter sperm membrane composition in vitro (to mimic in situ changes) while the final project will provide a summary test of the effect of known changes in lipid composition on the capacity of immature epididymal sperm to undergo an in vitro induced acrosome reaction.