氟环境下变形链球菌耐氟菌株ciaH、eno和pykF基因的差异表达及其意义

摘要

Objective:To investigate the relationship between ciaH, eno, pykF genes and fluoride resistance through determining the differential expressions of ciaH, eno and pykF genes of fluoride-resistant Streptococcus mutans cultivated in fluoride environment. Methods:The cultured Streptococcus mutans and their fluoride-resistant strains were divided into UA (Streptococcus mutans subcultured in BHI without NaF), FR (fluoride-resistant Streptococcus mutans subcultured in BHI without NaF) and FFR (fluoride-resistant Streptococcus mutans subcultured in BHI containing 1 g·L-1 NaF) groups.After 11 h (logarithmic phase) and 20 h (platform stage) cultivation, the expression levels of ciaH, eno and pykF mRNA were detected by RT-PCR method.Results:Compared with FR group, the expression levels of ciaH, eno and pykF mRNA in FFR group were increased both in the logarithmic phase and the platform stage(P<0.05 or P<0.01).Compared with UA group, the expression levels of eno and pykF mRNA in FR group were decreased both in the logarithmic phase and the platform stage(P<0.01), whereas the expression level of ciaH mRNA had no significant difference in the logarithmic phase (P>0.05), but it was increased in the platform stage (P<0.01).Conclusion:Fluoride can increase the expression levels of ciaH, eno and pykF genes in fluoride-resistant Streptococcus mutans, indicating that these genes are related to the production of fluoride resistance.%目的:检测变形链球菌耐氟菌株在氟环境下ciaH、eno和pykF基因表达的差异,探讨ciaH、eno和pykF基因与变形链球菌氟抗性的关系.方法:变形链球菌亲代菌株及其耐氟菌株,分为亲代组(变形链球菌亲代菌株生长于无氟BHI培养基中)、耐氟组(耐氟菌株生长于无氟BHI培养基中)和含氟组(耐氟菌株生长于含氟量为1 g·L-1的BHI培养基中).分别选取3组处于生长对数期(11 h)和稳定期(20 h)的菌株,采用RT-PCR法检测ciaH、eno和pykF mRNA表达水平.结果:与耐氟组比较,含氟组的耐氟菌株ciaH、eno和pykF mRNA表达水平在对数期和稳定期均明显升高(P<0.05或P<0.01);与亲代组比较,耐氟组的耐氟菌株eno和pykF mRNA表达水平在对数期和稳定期均明显降低(P<0.01),ciaH mRNA表达水平在对数期差异无统计学意义(P>0.05),在稳定期明显升高(P<0.01).结论:氟能提高耐氟菌株ciaH、eno和pykF基因的表达,该组基因与耐氟菌株氟抗性的产生有关联.