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目的 2型猪链球菌是重要的人畜共患病病原菌,鉴定现有的和发掘新的毒力因子依然是该领域的研究热点。探讨SSU05_0736编码的c AMP受体蛋白在2型猪链球菌(Streptococcus suis serotype 2,S.suis 2)中国强毒株05ZYH33中的作用机制,初步分析SSU05_0736基因敲除株的生物学特性,为进一步研究猪链球菌可能的毒力因子及其致病机制提供研究基础。方法利用同源重组原理构建并筛选由壮观霉素抗性基因(Spcr)替换S.suis 2中SSU05_0736的基因敲除株Δ0736,系统比较分析野毒株与敲除株的生物学特性,同时将BALB/c小鼠作为动物感染模型来探究敲除株的毒力。结果通过组合PCR、反转录PCR(RT-PCR)等方法鉴定并成功构建基因敲除株Δ0736,其在菌落形态、溶血活性及对小鼠致病力等方面与野毒株无显著差异;两者生长速率相比,敲除株的生长较野毒株迟缓但其在对数期增长速率较大。结论 SSU05_0736基因的缺失并未使猪链球菌2型强毒株05ZYH33的毒力发生显著改变,推测SSU05_0736基因并非毒力决定因子,但与野毒株相比敲除株在生长速率尤其对数期增长速率较大这一方面的改变,提示可对其代谢调控能力作进一步分析。
Objective Streptococcus suis type 2 is an important pathogen of zoonosis. Identification of existing and new virulence factors remains a hot topic in this field. To investigate the mechanism of SSU05_0736 encoding cAMP receptor protein in Chinese zoonotic strain 05ZYH33 of Streptococcus suis serotype 2 (S.suis 2), and to analyze the biological characteristics of SSU05_0736 knockout strain further To study the possible virulence factors of Streptococcus suis and its pathogenesis provide the basis for the study. Methods The gene knockout strain Δ0736 of SSU05_0736 was replaced by spectinomycin resistance gene (Spcr) by homologous recombination. The biological characteristics of wild-type and knockout strains were compared and analyzed. At the same time, BALB / c mice were used as an animal model to investigate the virulence of knockout strains. Results The knockout strain Δ0736 was identified and identified by combinatorial PCR and reverse transcription PCR (RT-PCR). The results showed that there was no significant difference between colony morphology, hemolytic activity and virulence in mice. Compared with the growth rate, the growth of knock-out strain was slower than that of wild-type strain, but its growth rate in logarithmic phase was larger. Conclusions The deletion of SSU05_0736 gene did not significantly change the virulence of S. suis type 2 virulent strain 05ZYH33. It was speculated that SSU05_0736 gene was not virulence determinant, but the growth rate of knockout strain was especially increased in logarithmic phase A large rate of change in this area, suggesting that its ability to regulate metabolism for further analysis.