中文摘要：

为探讨七鳃鳗性腺组织中是否含有具有纤溶活性的菌株,以日本七鳃鳗（Lampetra japonica）的性腺组织为材料,筛选分离出1株高效的具有纤维蛋白原水解酶活性的菌株,并通过形态学观察和16SrDNA序列对其进行鉴定及系统发育分析。采用纤维平板法检测了其上清液的纤维蛋白水解酶活性。分离菌株的上清液能够于0.5h内迅速降解纤维蛋白原的Aα链和Bβ链。此外,纤维蛋白平板实验结果显示该上清液不具有纤维蛋白水解酶和纤溶酶原激活剂的活性。形态学观察及16SrDNA序列分析结果表明该活性菌株为革兰氏阴性直杆菌,与中间气单胞菌（Aeromonas media,登录号为AF418217）的同源性最高,其相似度可高达99.7%。该活性菌株被鉴定为气单胞菌,并命名为气单胞菌L1（Aeromonas L1,Genebank登录号为KP255445）。

英文摘要：

In order to clarify whether gonad tissues in lampreys contain bacteria with fibrinogenolytic property,the gonad tissues of Japanese lampreys（Lampetra japonica）were used to separate a bacterium with higher fibrinogenolytic activity in the present study.The bacterium was identified by morphological observation and 16 SrDNA sequence analysis.In addition,phylogenetic tree was also constructed.And its fibrinolytic activity was analyzed by fibrin plate assay.The results show the supernatant of the separated bacterium is able to degrade the Aαand Bβchains of fibrinogen within half an hour.According to the analysis of fibrin plate,the supernatant does not degrade fibrin or activate plasminogen.Morphological observation and 16 SrDNA sequence analysis show that the isolated bacterium is a gram-negative bacillus,which shows high homology with the Aeromonas media（registration number：AF418217）.And the highest similarity is about 99.7%.Thus,this bacterium is identified and named as Aeromonas L1 and its Genebank registration number is KP255445.