东北三省9株嗜水气单胞菌16S rDNA序列比较研究

Comparison Study on 16S rDNA of Nine Aeromonas hydrophila Isolated from Northeast Provinces

采用特异性引物对采自黑龙江、吉林及辽宁省的9个嗜水气单胞菌分离株的保守基因16SrDNA部分序列进行PCR特异性扩增,对所得686bp扩增产物进行测序并比较研究。序列分析显示,东北三省的9个分离株同源性极高,都在百分之九十以上,测得基因序列共有保守位点613个,变异位点73个,简约信息位点3个。辽宁省与吉林省分离株遗传距离为0.005049;辽宁省与黑龙江省为0.005049;而吉林省与黑龙江省为0.004232。以致伤弧菌为外群的MP及NJ聚类树聚类结果一致,黑龙江省的第一和第二分离株聚成一个分支,而其他各分离株聚成另外一个大的分支,其中辽宁省的第二分离株与吉林省的第一和第二分离株又聚为一个较小的分支。实验结果表明,9个分离株相应保守区16SrDNA片段变化较小,同源性极高,聚类不明显,没有形成明显的区域性或特异性的变化。

A part of 16S rDNA fragments was amplified using specific primers to detect nine Aeromonas hydrophila strains isolated from Heilongjiang Province,Jilin Province and Liaoning Province.As a result,686bp sizes of fragments were sequenced and analyzed between nine Aeromonas hydrophila strains.Sequence alignments showed that the nine isolates from three provinces were highly homologous with more than 90% similarity.Among of the obtained sequences,there existed 613 conservative sites,73 variable sites and 3 parsimony informative sites.The genetic distance calculated by MEGA software indicated that genetic distance was 0.005049 between the isolates from Liaoning and Jilin Provinces,0.005049 between Liaoning and Heilongjiang Provinces,and 0.004232 between Jilin and Heilongjiang Provinces.Cluster analysis also showed that the results were basically consistent with the outside group of Vibro vulnificus using two methods of maximum-parsimony （MP）and Neighbor-joined （NJ）.The results suggested that the first isolate and the second isolate from Heilongjiang Province clustered together,while the other isolates were clustered to a large branch.Additionally,the second isolate from Liaoning Province and the two isolates from Jilin Province clustered to a smaller branch.To sum up,there was a little difference among the conservative sites of 16S rDNA from nine isolates with highly homology.Cluster analysis further confirmed that no regional or specific changes formed among the nine isolates from three provinces.