网箱养殖患病草鱼细菌分离鉴定与回复感染研究

利用常用细菌分离纯化方法从患病草鱼中分离出7株菌株,分别编号为Ⅰ～Ⅶ;对7株菌株的16SrRNA基因序列进行PCR扩增,均得到长约600bp的片段;将扩增结果进行测序,测序结果输入到美国国立生物技术信息中心(NCBI,http://www.ncbi.nlm.nih.gov/),用BLAST工具对序列进行同源性比对分析.结果表明:Ⅰ为沙雷氏菌,同源性达95%;II为腐生葡萄球菌,同源性达99%;III为荧光假单孢菌,同源性达97%;IV为产碱普罗威登斯菌,同源性达99%;V为嗜水气单孢菌,同源性达99%;VI为杀鲑气单孢菌,同源性达97%;VII为不动菌属,同源性达97%.将Ⅰ～Ⅶ号菌株回复感染健康草鱼,结果沙雷氏菌、腐生葡萄球菌、荧光假单孢菌、产碱普罗威登斯菌和嗜水气单孢菌对草鱼的危害较大,而杀鲑气单孢菌和不动菌属的感染症状不明显.

A Preliminary Study of Isolation and Identification of Pathogenic Bacteria from Net Cage-Cultured Ctenopharyngodon idellus and Retrieved Infection

In the present experiment,the traditional microbiology method was used to isolate the endophytic bacteria from Lateolabrax japonicus of net cage culture in the Wujiang River.A total of 7 strains were isolated.Their 16S rRNA gene sequences were amplificated by PCR,and 600 bp fragments were obtained.These 600 bp fragments were successfully sequenced and entered into the NCBI(http: //www.ncbi.nlm.nih.gov /).Alignment analysis was made by BLAST tool to analyse the homology.The results showed that the 7 stains were Serratia proteamaculans(homology of 95%),Staphylococcus saprophyticus(homology of 99%),Pseudomonas fluorescens(homology of 97%),Providencia alcalifaciens(homology of 99%),Aeromonas hydrophila(homology of 99%),Aeromonas salmonicida(homology of 97%),and Acinetobacter(homology of 97%).The bacteria were used for retrieved infection of the healthy C.idellus.S.proteamaculans,S saprophyticus,P.fluorescens,P.alcalifaciens and A.hydrophila were shown to have comparatively large hazard to grass carp,while A.salmonicida,and Acinetobacter induced no obvious infection.