猪链球菌细菌素的筛选及理化特性分析

Screening and physicochemical properties of Streptococcus suis bacteriocin

为研究猪链球菌(SS)产生的细菌素,本研究以不同省份分离到的200株SS为研究对象,采用琼脂扩散法筛选具有抑菌作用的菌株;通过CGE网站进行ST型分型,利用PCR方法进行血清型分型;选出的菌株利用PCR方法检测细菌素相关基因;然后用BAGEL4对细菌素相关基因进行全序列基因功能分析,同时采用PCR分段扩增其基因簇;并分析SS所产细菌素的理化特性。结果显示,从200株SS中筛选出了21株可产生抑菌物质的SS,它们分布于不同的ST型和血清型。其中菌株xj-144和38-3携带SS细菌素编码基因sss基因和suiA基因,经BAGEL4分析菌株xj-144仅存在一个与suicin 65核心肽相同的细菌素,并无其他潜在细菌素,其完整的基因簇含有10个ORFs,产生的细菌素排除有机酸、过氧化氢干扰后,其粗提取液具有一定的耐热性、酸碱耐受性和蛋白酶稳定性,并对部分病原菌具有抑菌作用。本研究为进一步研究SS细菌素奠定了一定的基础,为实现细菌素替代传统抗生素提供了科学参考。

To study the bacteriocin produced by Streptococcus suis(S. suis), 200 strains of S. suis isolated from different provinces were used as the research object, and agar diffusion method was used to screen the bacteriostatic strains. ST typing was performed on CGE website, and serotyping was performed by PCR. The bacteriocin-related genes of the selected strains were detected by PCR. After gene function mining by using the BAGEL4 software, the PCR fragments were amplified to verify the gene cluster. The physicochemical properties of the bacteriocin produced by the selected strains were analyzed. The results showed that21 strains out of 200 isolates of S. suis were verified to produce bacteriostatic substances, they were distributed in different ST and serotypes. Among which strain xj-144 and 38-3 carried S. suis bacteriocin encoding gene sss and suiA. According to BAGEL4 analysis, only one bacteriocin was produced in strain xj-144, and its complete gene cluster was consist of 10 ORFs. After eliminating the interference of organic acid and hydrogen peroxide, the crude extract of bacteriocin displayed certain resistance to heat, acid,base and protease, and had bacteriostatic effect on some pathogenic bacteria. This study laid a certain foundation for further study of the S. suis bacteriocin and provided scientific reference for the replacement of traditional antibiotics with bacteriocin.