sahH 基因在变异链球菌 LuxS 缺陷株内表达对胞外多糖合成的影响
Function of sahH gene in exopolysaccharides synthesis of Streptococcus mutans LuxS null strain

目的 · 研究 sahH 基因在变异链球菌 LuxS 缺陷株内的表达对其胞外多糖合成的影响。方法 · 以构建的 LuxS 缺陷株转有 sahH 基因的 sahH+ luxSSmUA159、LuxS 缺陷株转有空质粒的 PIB169+ luxSSmUA159（背景对照）及变异链球菌 SmUA159 野生株为研究模型。实时荧光定量 PCR 观察胞外多糖合成相关基因的转录水平，蒽酮法观察生物膜胞外多糖合成情况。结果 · 与 SmUA159 和 PIB169+ luxSSmUA159 菌株相比，sahH 基因转入株 sahH+ luxSSmUA159 的 4 种被检测基因（gtfA、gtfB、gtfC、gtfD）中，gtfA 和 gtfD 转录水平有显著差异（均 P<0.05），而 gtfB 和 gtfC 无明显差异。SmUA159、PIB169+ luxSSmUA159 和 sahH+ luxSSmUA159 胞外多糖合成量无明显差异。结论 · sahH 基因转入可影响变异链球菌胞外多糖合成相关基因的表达，但不影响细菌总体胞外多糖合成量。
：Objective · To investigate the function of sahH gene in exopolysaccharides synthesis of Streptococcus mutans LuxS null strain. Methods · sahH+ luxSSmUA159 was constructed by introducing sahH gene into Streptococcus mutans LuxS null strain, while PIB169+ luxSSmUA159 and its wild strain SmUA159 were used as vector control and blank control. Real-time qPCR and anthrone test were performed to investigate the differences in exopolysaccharides synthesis among sahH+ luxSSmUA159, PIB169+ luxSSmUA159 and the wide-type strain SmUA159. Results · The transcriptional levels of gtfA and gtfD were upregulated in the sahH+ luxSSmUA159, compared to SmUA159 and PIB169+ luxSSmUA159 (both P<0.05), but there was no statistical difference in the transcriptional levels of gtfB and gtfC. The results of the anthrone test showed exopolysaccharides synthesis of the three groups was also similar. Conclusion · sahH gene affects the expression of some genes related to exopolysaccharides synthesis, but it has little effect on the whole content of bacterial exopolysaccharides