Agglutination of jelly coat and cortical granule components and the block to polyspermy in the amphibian Xenopus laevis.
Agglutination of jelly coat and cortical granule components and the block to polyspermy in the amphibian Xenopus laevis.
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两栖动物非洲爪蟾中果冻层和皮质颗粒成分的凝集以及对多精受精的阻碍。
DOI：
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发表时间：
1974
影响因子：
11.1
通讯作者：
J. L. Hedrick
中科院分区：
文献类型：
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作者：
R. E. Wyrick;T. Nishihara;J. L. Hedrick
在两栖动物受精时，通过将卵黄膜转化为受精膜，建立了阻止多精受精的机制。在非洲爪哇，受精时被膜的一个主要超微结构变化是在被膜和最内层的凝胶层J(1)之间出现一个电子致密层，称为F层。F层至少部分来源于皮质颗粒释放的物质。使用分离的皮质颗粒(CG)渗出物和凝胶层J(1)进一步定义F层的来源和化学性质。在双扩散实验中，分离的组分在凝集反应中相互作用，产生一条沉淀带。凝集反应涉及α-半乳糖苷残基和金属离子(Ca(++))。利用化学修饰凝胶，我们证明了凝集过程中不涉及巯基-二硫键交换，并且用(35)S标记的凝胶，凝集的J(1)组分含有硫酸酯。CG渗出物和J(1)组分都含有碳水化合物，凝集素活性证明了这一点。许多离子聚合物，无论是天然的还是合成的，都被测试为CG渗出物和J(1)的化学类似物；没有一种给出凝集带。两种不同种类青蛙卵溶解的凝胶层物质与CG渗出物凝集，而海胆卵的凝胶层和哺乳动物卵的透明质酸不凝集。因此，这种凝集反应在化学和系统发育上是特异的。当胶状未受精卵浸泡在CG渗出液中时，在卵黄膜外层形成的类似于F层的电子致密层；这样的卵是不能受精的。我们认为，在非洲爪哇，也许还有其他生物，皮质颗粒成分和卵子被之间的凝集型反应是建立对多精受精的阻碍的结构和分子事件的参与者。
A block to polyspermy in amphibians is established at fertilization by the conversion of the vitelline envelope to the fertilization envelope. In Xenopus laevis a major ultrastructural change in the envelope at fertilization is the appearance of an electron-dense layer, termed the F layer, between the envelope and the inner-most jelly coat layer, J(1). The F layer is derived, at least in part, from materials released from the cortical granules. Further definition of the origin and chemical nature of the F layer was sought by using isolated cortical granule (CG) exudate and jelly coat layer J(1). In double diffusion experiments, the isolated components interacted in an agglutination reaction producing a band of precipitation. The agglutination involved alpha-galactoside residues and metal ions (Ca(++)). Employing chemically modified jelly, we demonstrated that sulfhydryl-disulfide interchanges were not involved in the agglutination and, with (35)S-labeled jelly, that the agglutinating J(1) component possessed sulfate esters. Both the CG exudate and the J(1) components contained carbohydrate, as evidenced by their lectin reactivity. A number of ionic polymers, both natural and synthetic, were tested as chemical analogs of CG exudate and J(1); none gave an agglutination band. Dissolved jelly coat material from eggs of two different species of frogs agglutinated with CG exudate, while jelly from sea urchin eggs and hyaluronic acid from mammalian eggs did not. Thus, the agglutination reaction was chemically and phylogenetically specific. An electron-dense layer, similar to the F layer, formed on the outer of the vitelline envelope when jellied unfertilized eggs were immersed in CG exudate; such eggs were not fertilizable. We suggest that in Xenopus laevis, and perhaps other organisms as well, an agglutination type of reaction between cortical granule components and egg integuments is a participant in the structural and molecular events establishing a block to polyspermy.