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

盲鳗或粘鱼形目是最原始的脊椎动物群的一员，也是一种具有生殖功能的动物，其受精过程尚不清楚。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。介绍了一种顶体反应的八目鳗，Eptatretus burgeri的精子，成功地实现了处理成熟的精子与离子霉素和过量的Ca ~（2+）。精子产生一个顶体突起，从精子头顶端开始延伸。这种反应类似于无脊椎动物精子的反应，而不是脊椎动物精子的反应。反应时，在顶体囊泡的开口附近形成一些囊泡。在日本和太平洋盲鳗精子的顶体囊泡的胞吐作用中观察到这种囊泡。我调查的第一次的细结构形成的珠孔区域在盲鳗卵在卵子发生的后期阶段，专注于底部区域的珠孔和卵表面。在这些阶段中，许多珠孔细胞穿过绒毛膜到达卵表面的凹坑。细胞与绒毛膜之间被一层无定形物质隔开，与卵表面之间被另一层陷窝中的纤维层隔开。在后期，珠孔细胞堆松散，与卵表面层之间出现空隙。这些结构与硬骨鱼类在同一区域所观察到的结构有明显的不同。提出了一个假说，即从原脊索动物到硬骨鱼类的卵子和精子形态之间可能存在联系。我们研究了蛋白酶体通过调节外臂动力蛋白轻链的cAMP依赖性磷酸化来调节鲑鱼精子的运动。

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.