Ohta T, Yoshida M, Kato S
Department of Biological Science, Aichi University of Education, Kariya City, Japan.
Cell Struct Funct. 1998 Jun;23(3):179-86. doi: 10.1247/csf.23.179.
The effects of cytochalasin B (CB), which acts on microfilaments, on sperm penetration into eggs of a teleost fish were investigated ultrastructurally. Eggs from the rose bitterling, Rhodeus ocellatus ocellatus, were pre-treated in physiological saline containing CB and inseminated in water also containing CB. Microvilli at the sperm entry site (SES) under the micropyle disappeared or shortened in length following CB treatment. However, a spermatozoon attached to and fused with the SES of CB-treated eggs. The spermatozoon present in a swollen mass (SM) remained at the egg surface even after membrane fusion and did not enter the cortex. It was unclear whether or not sperm movement from the cortex to the inner cytoplasm is CB-sensitive. The SM formed and plugged the micropyle. CB did not inhibit cortical alveolus breakdown. Based on the present experiments with fish eggs, it is concluded that CB inhibits sperm movement from the egg surface to the cortex, but not sperm attachment (binding), membrane fusion and SM formation during the process of sperm penetration.
研究了作用于微丝的细胞松弛素B（CB）对硬骨鱼精子穿透卵子的影响，并进行了超微结构观察。将玫瑰无须鲃（Rhodeus ocellatus ocellatus）的卵子在含有CB的生理盐水中预处理，然后在同样含有CB的水中进行授精。CB处理后，卵膜孔下方精子进入位点（SES）处的微绒毛消失或长度缩短。然而，精子仍能附着并与经CB处理的卵子的SES融合。即使在膜融合后，存在于肿胀团块（SM）中的精子仍停留在卵表面，未进入皮质层。尚不清楚精子从皮质层向卵内细胞质的移动是否对CB敏感。SM形成并堵塞了卵膜孔。CB并未抑制皮质泡破裂。基于目前对鱼卵的实验，得出结论：CB抑制精子从卵表面向皮质层的移动，但不抑制精子在穿透过程中的附着（结合）、膜融合和SM形成。
