Løvtrup Søren
Department of Histology, University of Göteborg, Schweden.
Wilhelm Roux Arch Entwickl Mech Org. 1965 Jun;156(2):204-248. doi: 10.1007/BF00573873.
The morphology of the cortex of the amphibian egg is discussed, with special reference to the hyaline membrane.The physical properties of the cortex are reviewed, especially those evidenced by the wound healing reaction. The participation of the hyaline membrane in this process is particularly emphasized.An analysis of the activation processes normally associated with fertilization indicates that they may be accounted for by three cortical contractions, two radially symmetrical, with center at the animal pole, and one asymmetrical (or bilaterally symmetrical) originating at the point of sperm entrance. The contractions may be spatially correlated with three wounds normally afflicted on the cortex, viz., the expulsion of the polar bodies and penetration of the sperm. The first cortical contraction leads to separation between egg surface and vitelline membrane, and consequently to rotation of orientation, the second leads to formation of the perivitelline space, and the third to grey crescent formation.The mechanisms of blastula formation and of volume regulation are finally discussed. The strong adhesion between the cells and the hyaline membrane are of special importance in the former process. The hydrostatic pressure exerted through the cortex tension of the individual cells is suggested to account for the transport of water against the osmotic pressure difference from cells to blastocoele. The tension in the hyaline membrane developing in the late blastula and early gastrula is suggested to control the volume of the embryo.
本文讨论了两栖类卵皮质的形态，特别提及了透明膜。回顾了皮质的物理特性，尤其是那些由伤口愈合反应所证明的特性。特别强调了透明膜在这一过程中的参与。对通常与受精相关的激活过程的分析表明，它们可能由三次皮质收缩引起，其中两次呈径向对称，以动物极作为中心，另一次不对称（或双侧对称），起始于精子进入点。这些收缩可能在空间上与皮质上通常出现的三处伤口相关，即极体的排出和精子的穿透。第一次皮质收缩导致卵表面与卵黄膜分离，进而导致方向旋转，第二次导致卵周隙形成，第三次导致灰新月体形成。最后讨论了囊胚形成和体积调节的机制。细胞与透明膜之间的强粘附力在前一过程中尤为重要。有人提出，通过单个细胞的皮质张力施加的静水压力可解释水逆渗透压从细胞向囊胚腔的运输。有人认为，在囊胚晚期和原肠胚早期形成的透明膜中的张力可控制胚胎的体积。
