论文部分内容阅读
为研究引起香鱼(Plecoglossus altivelis)出血溃烂症病因及致病菌系统发育地位,本研究从患病香鱼的肝脏、肾脏及体表分离到11株病原菌(编号:X0901-X0911),运用常规细菌生理生化方法鉴定致病菌所属种类;运用16SrRNA基因、recA基因序列分析方法研究致病菌的系统发育地位。细菌生理生化鉴定结果表明:致病菌为鳗利斯顿氏菌,11株细菌生理生化结果相同,均为革兰氏阴性杆菌、氧化酶阳性、接触酶阳性、吲哚阳性、精氨酸脱羧酶阳性、精氨酸双水解酶阳性、硝酸盐还原阳性、甘露醇阳性、MR测定阳性;H2S阴性、V-P测定阴性等。根据16SrRNA基因、recA基因序列分别构建弧菌科常见细菌系统进化树,结果表明:致病菌与鳗利斯顿氏菌(Listonella anguillarum)均聚为一枝,聚类结果与细菌生理生化鉴定结果相符。致病菌与鳗利斯顿氏菌16SrRNA基因、recA基因的同源性分别为99.9%、99.8%。以recA基因构建的系统进化树的拓扑学结构与16SrRNA基因建树结果相类似。此外,与16SrRNA基因相比,recA基因在不同物种之间具有更高的鉴别能力,本研究表明recA基因适合作为弧菌科常见细菌物种间进化关系研究的标记。
In order to study the etiopathogenisis of pathogenic bacteria and pathogenesis of bleeding ulcer in Plecoglossus altivelis, 11 pathogenic bacteria (No.X0901-X0911) were isolated from the liver, kidney and body surface of diseased sweetfish, Bacterial physiological and biochemical methods to identify the types of pathogens; using 16SrRNA gene, recA gene sequence analysis of pathogenic bacteria phylogenetic position. Physiological and biochemical identification of bacteria showed that the pathogens were L. eelinus, and the 11 strains had the same physiological and biochemical results. All were gram-negative bacilli, positive for oxidase, positive for contact enzyme, positive for indole and arginine decarboxylase Enzyme positive, arginine dihydrolase positive, nitrate reduction positive, mannitol positive, MR positive; H2S negative, VP negative and so on. According to 16S rRNA gene and recA gene sequences, the common bacterial phylogenetic tree of Vibrio was constructed respectively. The results showed that both pathogenic bacteria and Listonella anguillarum were clustered into one, and the clustering results were consistent with the results of bacterial biochemical identification . The homology of 16A rRNA gene and recA gene of pathogenic bacteria and L. eining was 99.9% and 99.8%, respectively. The topological structure of phylogenetic tree constructed with recA gene is similar to that of 16S rRNA gene. In addition, compared with the 16SrRNA gene, the recA gene has a higher ability to distinguish between different species. This study shows that the recA gene is suitable as a marker for the evolutionary relationships among common bacterial species in Vibrio.