Ⅱ型猪链球菌浙江分离株cps2J、ef、mrp基因的克隆及序列分析

Cloning and sequence analysis of the gene cps2J,ef and mrp of Streptococcus suis serotype2 in Zhejiang Province

目的阐明浙江省猪链球菌分离株的血清型分型,分析其与国内外其他猪链球菌Ⅱ型（SS2）菌株cps2J、ef、mrp毒力基因的差异。方法参照GenBank上已发表的cps2J、ef、mrp毒力基因序列,设计引物,对6株浙江省猪链球菌分离株进行cps2J、ef、mrp全基因克隆及序列测定,并与国内外其他分离株的基因序列进行比较。结果 cps2J、ef、mrp基因的完整开放阅读框（ORF）分别为999bp、2532bp、3771bp,各自编码333、843、1256个氨基酸。经对cps2J、ef、mrp毒力基因的序列比较与系统进化分析,6株浙江分离株均分布在SS2发生群中,与国内外其他SS2菌株cps2J、ef、mrp基因核苷酸的同源性均较高,分别为98.39%~100.0%、99.6%~100.0%和99.4%~100.0%,分离的年代和地区对基因的同源性和系统进化分支影响不大。结论 6株浙江省猪链球菌分离株为2型菌株,cps2J、ef、mrp基因序列非常保守,与GenBank上国内及欧洲SS2菌株中相应序列有很高的同源性,可能有着相同的起源。

In order to understand the serotype of Streptococcus suis in Zhejiang,the complete cps2J,ef and mrp gene were sequenced and compared with that of other SS2 strains.The total DNA which was extracted from SS2 Zhejiang strains were prepared.Specific primers were also designed and synthesized according to the sequence of cps2J,ef and mrp gene from GenBank to sequence the gene and compare with those other strains of SS2.All whole open reading fragment of cps2J,ef and mrp gene among 6 isolates of SS2 were 999bp,2 532bp and 3 771bp,encoding 333,843 and 1256 amino acids respectively.With sequence compaction and phylogenetic tree construction,6 strains of Zhejiang isolate were found to be Streptococcus suis serotype 2.The nucleotide of cps2J,ef and mrp gene of the 6 strains had high homology with other SS2 strains.The time and area of strains did not affect the homology and the inherited evolvement.This study shows six SS2 strains of Zhejiang isolate were Streptococcus suis serotype2.Results indicate that the sequences of complete cps2J,ef and mrp gene among 6 isolates of SS2 are very steady and these difference source strains are possibly from same origin.