Sperm chymotrypsin-like enzymes of different inhibitor-susceptibility as lysins in ascidians

Summary Inhibitory effects of three peptidyl phenylalaninals on fertilization and on chymotrypsin-like enzyme activity of sperm in three species of ascidians were examined. The results suggest that a sperm chymotrypsin-like enzyme is indispensable for the fertilization in each of the ascidians, and that these enzymes have different susceptibilities to inhibitors.12 November 1986Acknowledgments. We are indebted to Dr M. Hoshi of Tokyo Institute of Technology for his helpful discussion. This work was supportd by a Grant-in-Aid from the Ministry of Education, Science and Culture of Japan.     

蟾蜍(Bufo japonicus)细胞溶素基因筛选用探针的制备

利用阴离子交换、凝胶过滤和高压液相柱层析对细胞溶素基因进行了纯化,获得了纯度极高的酶样品．经ｌｙｓｉｌ 内肽酶进行定点酶切后,利用高压液相柱层析纯化出了该酶的多个短肽片段．其中,经测序获得了３ 个短肽片段的氨基酸序列．根据两栖动物中密码子的使用频率,可推测出其相应ｃ Ｄ Ｎ Ａ 的核苷酸序列,进而制备出了３ 个ｃ Ｄ Ｎ Ａ 探针．利用这些合成的探针,便可从精子ｃ Ｄ Ｎ Ａ 文库中筛选细胞溶素基因．     

可控性自裂解乳球菌的构建

为阐明发酵乳杆菌温和噬菌体φPYB5编码的由穿孔素(Hyb5)和裂解素(Lyb5)组成的裂解盒在乳酸菌中的作用特征,将hyb5-lyb5基因克隆到E. coli/L. lactis穿梭质粒pSEC的nisin诱导型启动子下游,构建了重组质粒pSEC-hyb5-lyb5。将pSEC-hyb5-lyb5电转入Lactococcus lactis NZ9000,获得重组菌株NZphl。经nisin诱导表达后,Hyb5-Lyb5表现出高的裂解活性,使NZphl菌液的浊度（OD600）急剧下降,并释放出大量胞内蛋白,为利用自裂解菌株生产优质乳制品奠定了基础。     

Localization of vitelline-coat lysin purified from testis of a top shell,Turbo cornutus

Summary The vitelline-coat lysin purified from the testis ofTurbo cornutus was found, by an immunofluorescence technique, to be located in the acrosome of the sperm, which suggested that the lysin reacts with the vitelline-coat in an early phase of fertilization to allow the sperm to penetrate through the coat.We are grateful to Professor M. Akino (Tokyo Metropolitan University) for his helpful advice.     

鲍精子细胞溶素研究进展

鲍精子细胞溶素(lysin)是所有动物繁殖蛋白中了解的最透彻的一种,作为一种非酶蛋白质,lysin可在卵黄膜上特异性地钻1个孔使精子从此孔进入.目前对lysin的研究主要集中在它的结构、生化、功能和进化等方面:lysin是一种由2个单体组成的二聚体分子,其单体为5个α-螺旋组成的螺旋束,lysin以二聚体形式与其糖蛋白受体(VERL)特异性结合,然后单体化,再与受体非特异性结合,这与普通动物细胞表面的分子识别的相关内容相一致;许多鲍lysin的氨基酸序列已经测定出来,并证实lysin是通过正向选择方式进化的,对于其进化的模式也有假设来说明,这对理解海洋新种的形成具有重要作用.