猪链球菌2型浙江嘉兴株毒力基因序列分析

Sequence analysis of two virulence factors from Streptococcus suis type 2 isolated in Jiaxing,Zhejiang province

目的猪链球菌2型(SS2)浙江嘉兴ZJJX2008分离株毒力基因序列测定与分析。方法提取菌株DNA,应用聚合酶链反应(PCR)扩增菌株Cps2J和EF基因全片段,克隆入质粒载体,纯化后测定序列,并与国内外其他分离株基因进行比较。结果 Cps2J、EF基因完整开放阅读框(ORF)分别为999,2532bp,各自编码333,843个氨基酸,ZJJX2008分离株Cps2J、EF基因与国内外SS2菌株核苷酸同源性分别为99.1%～100%和99.8%～99.9%,氨基酸同源性分别为99.2%～99.7%和99.3%～99.5%;ZJJX2008分离株Cps2J基因与猪链球菌1型荷兰分离株6555核苷酸和氨基酸同源性只有66.7%和51.8%。结论 ZJJX2008分离株为猪链球菌2型菌株,Cps2J、EF基因与国内外其他SS2分离株比较序列非常保守,变异不大。

Objective To analyze the sequences of Cps2J and EF gene of ZJJX2008 strain of Streptococcus suis type 2 isolated in Jiaxing.Methods Total DNA was extracted from SS2 ZJJX2008 strain and amplified by PCR.Cps2J and EF segments of ZJJX2008 strain genome were cloned and sequenced.The sequences were compared with those of other strains of SS2.Results The whole open reading fragments of Cps2J and EF gene of ZJJX2008 strain are 999 bp and 2 532 bp,respectively,encoding 333 and 843 amino acids.The ZJJX2008 strain has high homology with SS2 strains（99.1%-100% for Cps2J segment and 99.8%-99.9% for EF segment at the nucleotide level,99.2%-99.7% for Cps2J segment and 99.3%-99.5% for EF segment at the amino acid level） and low homology with SS1 strain 6 555.Conclusion ZJJX2008 strain is Streptococcus suis type 2.The sequences of complete Cps2J and EF segments are very conservative.