伤寒沙门菌不同生长期和不同应激下非编码RNA ArpH的表达

［摘要］目的: 探讨伤寒沙门菌(Salmonella enterica serovar Typhi，S. Typhi) 在不同生长时期和不同应激条件下非编码RNA ArpH的表达水平，以及双组分调节系统和氧应激调节因子对ArpH的调控作用。方法: 利用RNA印迹、qRT PCR分析伤寒沙门菌在不同生长期ArpH的表达；利用qRT PCR分析伤寒沙门菌在酸、氧、高渗和热等不同应激环境下ArpH的表达；利用qRT PCR分析伤寒沙门菌双组分调节系统基因(ompR、rcsB)和氧应激调节因子基因(oxyR)对ArpH表达的影响。结果： ArpH在伤寒沙门菌的对数晚期表达量最高，在从对数早期开始到达稳态期的转变中，其表达量逐渐增加，而进入稳态期后明显回落；ArpH表达水平在酸应激下明显下降，氧应激下明显增高，而高渗应激和42℃热应激下ArpH的表达无显著变化；当ompR、rcsB和oxyR基因缺失时，ArpH表达量均明显下降。结论： ArpH参与伤寒沙门菌对酸、氧应激的调节；伤寒沙门菌双组分调节系统OmpR、RcsB和氧应激调节因子OxyR对ArpH均有正向调控作用。

Expression of non-coding RNA ArpH in Salmonella enterica serovarTyphi in the different growth stages and under different stress conditions

[Abstract]Objective: To investigate the expression characteristics of ArpH under different environmental stress conditions and the effects of two component regulatory system genes and oxygen stress regulator gene on the expression of ArpH in Salmonella enterica serovar Typhi （S. Typhi）. Methods: The ArpH expression of S. Typhi in different growth stages were analyzed by Northern blotting and qRT-PCR. qRT-PCR was used to analyze ArpH expression in S. Typhi under different stress conditions, including acidic, oxidative, hyperosmotic and heat stress. Effects of two component regulation system genes (ompR, rcsB) and oxygen stress regulator gene (oxyR) on the expression of ArpH in S. Typhi were analyzed by qRT-PCR. Results: The expression of ArpH was the highest in S. Typhi at the late logarithmic phase. The expression of ArpH increased gradually from the early logarithmic phase to the stable phase, and decreased after the stable phase. The expression level of ArpH decreased significantly under acidic stress and increased under oxidative stress, while the expression of ArpH was not affected by hyperosmotic stress and heat stress. When ompR, rcsB and oxyR genes were deleted separately, the expression of ArpH decreased significantly. Conclusion: The ArpH was beneficial to bacterial growth in the acid and oxidative stress，the genes ompR, rcsB and oxyR of S. Typhi had a positive regulatory effect on ArpH.