Wolenski J S, Hart N H
Department of Biological Sciences, Rutgers University, New Brunswick, New Jersey 08903.
J Exp Zool. 1988 May;246(2):202-15. doi: 10.1002/jez.1402460213.
The effects of selected concentrations of cytochalasins B (1-10 micrograms/ml; CB) and D (10, 50 micrograms/ml; CD) on the morphology and fertilization of zebra danio (Brachydanio) eggs were studied primarily with light and scanning electron microscopy. Eggs pretreated with either CB (10 micrograms/ml) or CD (10, 50 micrograms/ml) prepared in Fish Ringer's solution-0.5% DMSO showed a flattened shape, alterations in the form of surface microplicae and microvilli, and occasional spontaneous exocytosis of cortical granules. All eggs preincubated in either CB or CD were activated upon transfer to tap water, showing cortical granule exocytosis, elevation of the chorion, and formation of a fertilization cone. When eggs were pretreated for 5 minutes with 1-5 micrograms/ml CB or 10 micrograms/ml CD and inseminated, they incorporated the fertilizing sperm and typically developed to the two-cell stage. A single sperm cell attached to and fused with the sperm entry site microvilli but failed to enter the cytoplasm in eggs preincubated with 10 micrograms/ml CB. Eggs that were immersed continuously in either CB (10 micrograms/ml) or CD (50 micrograms/ml) 15 seconds after insemination also failed to incorporate the fertilizing sperm. Treatment of eggs after insemination with CD (10 micrograms/ml), however, did not prevent sperm cell incorporation or fertilization cone formation. Our drug data suggest the presence of actin-containing filaments in the danio egg before and following fertilization. These filaments appear to play a role in maintaining the shape of the egg cell and its surface specializations and in the incorporation of the fertilizing sperm. The fertilization cone appears to form independently of actin polymerization.
主要通过光学显微镜和扫描电子显微镜研究了选定浓度的细胞松弛素B（1 - 10微克/毫升；CB）和细胞松弛素D（10、50微克/毫升；CD）对斑马鱼（短担尼鱼）卵形态和受精的影响。用鱼任氏液 - 0.5%二甲基亚砜配制的CB（10微克/毫升）或CD（10、50微克/毫升）预处理的卵呈现扁平形状，表面微褶和微绒毛形态改变，偶尔有皮质颗粒的自发胞吐作用。所有在CB或CD中预孵育的卵转移到自来水中后都会被激活，表现出皮质颗粒胞吐、卵膜升高和受精锥形成。当卵用1 - 5微克/毫升CB或10微克/毫升CD预处理5分钟后进行授精时，它们会结合受精精子并通常发育到二细胞阶段。单个精子细胞附着并与精子入卵点微绒毛融合，但在用10微克/毫升CB预孵育的卵中未能进入细胞质。授精后15秒连续浸入CB（10微克/毫升）或CD（50微克/毫升）中的卵也未能结合受精精子。然而，授精后用CD（10微克/毫升）处理卵并不能阻止精子细胞的结合或受精锥的形成。我们的药物数据表明，在斑马鱼卵受精前后存在含肌动蛋白的细丝。这些细丝似乎在维持卵细胞的形状及其表面特化以及受精精子的结合中起作用。受精锥的形成似乎独立于肌动蛋白聚合。
