中文摘要：

目的检测酸性环境对变形链球菌初始粘附相关基因srtA表达的影响。方法变形链球菌分别在初始pH为5.5和7.0的条件下培养,提取总RNA,逆转录成cDNA,利用TaqMan实时荧光定量PCR技术检测不同环境条件下变形链球菌初始粘附相关基因srtA的表达。结果酸性环境中高粘附能力变形链球菌srtA基因表达明显上调,低粘附能力菌株的srtA基因表达也升高但不具有统计学意义;中性环境中高粘附能力菌株srtA基因表达明显高于低粘附能力菌株,而在酸性环境中这种差异无统计学意义。结论酸性环境促进变形链球菌srtA基因表达可能是变形链球菌抵抗酸性环境的机制之一;变形链球菌对牙面的粘附力可能与其srtA表达的量有关。

英文摘要：

Objective To detect the influence of acidic environment on expression of srtA , the main initial adherence associated gene of S. mutans. Methods Total RNA was extracted from S. mutans after being cultured at initial pH of 5.5 and 7.0 and then reversely transcripted into cDNA. By utilizing TaqMan RT - RCR technique, we checked srtA expression. Results In acidic environment, srtA expression of S. mutans increased, but only the difference of more - adherent strains was significant ; srtA expression of more - adherent S. mutans strains was generally higher than that of less -adherent strains, but the difference in acidic environment was not significant. Conclusion The promotion of srtA expression may be one of the mechanisms underlying S. mutans acid resistance ; There might be some correlation between different expression ofsrtA gene and S. mutans initial adherence.