Study of Fertillization of the hagfish, Eptatretus burgeri (Agnatha)

盲鳗或粘形目是最原始的脊椎动物群的一员，也是一种系统发育感兴趣的动物，其受精情况尚不清楚。我计划对配子进行研究，目的是成功地使该物种受精，并获得了如下所述的有趣结果。*通过离子霉素和过量Ca2+处理成熟精子，成功地引入了盲鳗（Eptatretus burgeri）精子的顶体反应。精子产生一个顶体突起，从精子头的顶端拉长。这一反应与无脊椎动物精子的相似，而与脊椎动物精子的相似。*反应时，顶体囊泡开口附近形成一些囊泡。这些囊泡在日本和太平洋盲鳗精子顶体囊泡的胞吐过程中被观察到。*首次研究了盲鳗卵发生后期微孔区形成的精细结构，重点研究了微孔底部区域和卵表面。在这些阶段，许多微孔细胞穿透绒毛膜到达卵表面的一个小坑。细胞被一层无定形物质壁与绒毛膜分开，被卵坑中的另一层纤维层与卵表面分开。在后期阶段，微孔细胞的堆叠松动，并且在堆叠和卵表面的层之间出现了空间。这些结构与在硬骨鱼的同一区域观察到的结构明显不同。提出了一种假说，认为原脊索动物到硬骨鱼的卵子和精子形态之间可能存在关系。*我们研究了蛋白酶体通过调节camp依赖的外臂动力蛋白轻链磷酸化来调节鲑科鱼类精子的运动。

Fertilization of the hagfish or myxiniformes, a member of the most primitive vertebrate group and and an animal of phylogenic interest, is unknown. I planned studies of the gametes with the aim of succeeding in fertilization of the species and obtained interesting results as described below.*Introduction of an acrosome reaction for spermatozoa in the hagfish, Eptatretus burgeri, was successfully achieved by treatment of mature spermatozoa with ionomycin and excess Ca2+. The spermatozoon produced an acrosomal process that elongated from the apex of the sperm head. The reaction bears resemblance to thet of invertebrate spermatozoa rather than that of vertebrate spermatozoa.*At the reaction, some vesicles were formed near the opening of the acrosomal vesicle. Such vesicles were observed at the exocytosis of the acrosomal vesicle in both Japanese and Pacific hagfish spermatozoa.*I investigated for the first time the fine structure of formation of the micropylar region in hagfish eggs during late stages of oogenesis, focusing on the bottom region of the micropyle and the egg surface. During these stages many micropylar cells penetrated through the chorion and reached a pit of the egg surface. The cells were separated from the chorion by a wall of amorphous material and from the egg surface by another fibrous layer in the pit. In the later stages, the stack of the micropylar cells loosoned, and a space appeared between the stack and the layer on the egg surface. The structures are markedly different from those observed in the same region of teleost fishes. A hypothesis that a possible relationship between egg and sperm morphology from protochordates to teleosts was suggested.*We investigated that proteasomes regulate the motility of salmonid fish sperm through modulation of cAMP-dependent phosphorylation of an outer arm dynein light chain.