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为了解云南某渔场罗非鱼大量死亡的原因,通过病原分离纯化,表型鉴定及16SrRNA测序分析,从发病和濒死鱼中分离纯化了4株革兰阴性杆菌(Av1、Av2、Av3、Av4),其培养特性、菌体形态、生化特征与维罗纳气单胞菌相同;用PCR方法扩增4株纯化菌的16SrRNA基因,得到大小相同的片断,选取条带明亮的Av3进行16SrRNA测序分析,与GenBank中的维罗纳气单胞菌B565株核苷酸同源性为100%。用核苷酸同源性99%以上的序列构建系统进化树,Av3与运动性气单胞菌聚类。综合动物回归试验结果,确定维罗纳气单胞菌(Aeromonas veronii)是导致该渔场罗非鱼大量死亡的主要病原之一。
In order to understand the causes of the large number of deaths of tilapias in a fishery in Yunnan, four strains of Gram-negative bacilli (Av1, Av2, Av3, Av4) were isolated and purified from diseased and moribund fish by pathogen isolation and purification, phenotyping and 16S rRNA sequencing analysis ), And its culture characteristics, morphology and biochemical characteristics were the same as that of Aeromonas aeruginosa. The 16SrRNA genes of four strains were amplified by PCR to obtain 16SrRNAs with the same size and bright bands of Av3 Analysis, and GenBank Aeromonas B565 nucleotide homology was 100%. Phylogenetic tree was constructed by using more than 99% homology of nucleotide sequences. Av3 clustered with Aeromonas sobria. Based on the results of the animal regression test, it was confirmed that Aeromonas veronii is one of the major pathogens that caused a large number of deaths of tilapias in this fishing ground.