一株牙鲆出血症病原菌的分子生物学鉴定

Classification and Molecular Biological Analysis of One Pathogenic Bacterium Associated with Hamorrhages of Cultured Flounder

从患出血症养殖牙鲆分离到一株病原菌M 4 ,革兰氏阴性 ,杆状 ,有极生和侧生鞭毛 ,能运动 ,菌落半透明。进行了常规生理生化和BIOLOG GN细菌鉴定系统测试 ,结果表明菌株M 4与V .carchariae的表型特征非常相似。为了进一步确定M 4的分类学地位 ,测定了其 16SrRNA基因序列 ,分析了相关细菌相应序列的同源性 ,构建了系统发生树 ,结果表明菌株M 4与V .carchariae的亲缘关系最近。综合上述结果 ,菌株M 4可鉴定为Vibirocarchariae。

A pathogenic bacterial strain M4 isolated from the haemorrhagic flounder (Paralichthys olivaceus) was reported in the present paper. Morphology observation showed it to be a motile and translucent gram negative bacterium with rod shape, polar and lateral flagella. The traditional physiological and biochemical methods, together with the BIOLOG-GN (gram negative) system were applied in the bacterial classification. Results showed that strain M4 was similar to Vibrio carchariae in most of the phenotypes. To investigate the phylogenetic position of this pathogen, a 1456 kb of 16S rRNA gene of M4 was sequenced and compared with that of related strains. Molecular phylogenetic dendrogram was constructed based on the genetic distance analysis, which revealed that strain M4 exhibited the highest levels of similarity to the Vibrio carchariae. Based on the results obtained, strain M4 was identified as Vibrio carchariae.