致病性猪源肠球菌16S rDNA-RFLP研究及系统进化分析

The RFLP investigation and phylogenetic analysis of 16S rDNA of Enterococcus of swine

为探讨分离自河南滑县、武陟等12个地区的猪源肠球菌的亲缘关系,采用对其16SrDNA基因的RFLP分析、序列分析及系统进化树的构建等方法,对12株疑似猪源肠球菌进行了研究;结果显示,12株分离株均与肠球菌同源性最高,同源率达98.1%～100%;而与猪链球菌同源率最高达85.5%,且进化树中12株菌株均位居与猪链球菌并列的肠球菌主干分支中。HandⅢ、XbaⅠ、EcoRⅠ分别对12株球菌的16SrDNA-RFLP分析发现,它们在该片段上有限制性位点,但没有产生限制性片段长度多态性;而HinfⅠ单酶切结果出现了限制性片段长度多态性,且12株分离株可分为两大rDNA图谱类群,与实际测序分析的酶切位点相一致,且找到鉴定肠球菌的350bp的分子标记。说明所分离12株球菌均是肠球菌,且不同地理种群已出现分化。

By the methods of RFLP analysis of 16S rDNA,sequence analysis,the construction of the phylogenetic tree,relationship of the suspect strains of Enterococcus from swine in twelve regions isolated from Huaxian,Wuzhi and etc were investigated.The results showed：All the isolated strains shared 98.1% to 100% sequence homology with Enterococcus and 85.5% homology with the Streptococcus of swine;In the phylogenetic tree,the twelve isolated strains were in the main stem of Enterococcus.In addition,the isolated strains was digested by HandⅢ,XbaⅠ,EcoRⅠ,which produced the same restriction sites,but no RELP appears;In contrast,RELP were found products in the digested by HinfⅠ,which showed two rDNA map group.Both results were consistent with the theoretic restriction enzyme cutting site,and a molecular marker of 350 bp identifying Enterococcus was found.It indicated that the twelve isolated stains were all Enterococci,and the populations of different geography appeared to be differentiation.