牙鲆与大菱鲆病原迟钝爱德华氏菌生物学特性及系统发育学分析

对从7起牙鲆（Bastard halibut，Paralichthys olivaeeus L．）、3起大菱鲆（Turbot，Scophdudmus maximus L．）病害的病（死）鱼中分离到的相应病原菌较系统地进行了形态特征、理化特性等表观分类学指征的鉴定及代表菌株DNA中G＋Cmol％的测定。同时，择代表菌株进行了16SrRNA基因的分子鉴定，测定了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，分离鉴定的148株菌均为爱德华氏菌属（Edwardsiella Ewing and McWhorter 1965）的迟钝爱德华氏菌（E．tarda），其中128株为迟钝爱德华氏菌野生型（E．tarda wild type）菌株，20株暂定为迟钝爱德华氏菌吲哚阴性变异株。代表菌株（HC010907—1及HC010830-1）的16SrRNA基因序列，与GenBank数据库中的迟钝爱德华氏菌的同源性均在99％。

Biological characterization and phylogenetic analysis of pathogenic E.tarda isolated from flounder (Paralichthys olivaceus) and turbot (Scophthalmus maximus)

Identification of extensive phenotypic information including morphological, physiological and biochemical characteristics of the pathogenic bacteria isolated from seven cases of flounder (Paralichthys olivaceus) and 3 cases of turbot (Scophthalmus maximus) was conducted, and the mol% G+C ratio of the DNA for the representative strains were detected. In addition, the molecular identification of 16S rRNA gene for the representative strains was performed, the 16S rRNA gene was sequenced and compared with that of related strains, and the molecular phylogenetic dendrogram was constructed. The results showed that the isolated 148 strains belonged to E.tarda of Edwardsiella, 128 strains were identified as E.tarda wild type and 20 strains were identified as E.tarda indole-negative. The 16S rRNA gene sequence of the representative strains (HC010907-1 and HC010830-1) exhibited high similarity (99%) with the 16S rRNA gene of E.tarda from GenBank database.