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首页> 外文期刊>Infection and immunity >PhoP-PhoQ-Regulated Loci Are Required for Enhanced Bile Resistance in Salmonella spp.
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PhoP-PhoQ-Regulated Loci Are Required for Enhanced Bile Resistance in Salmonella spp.

机译：PhoP-PhoQ调控的基因座是沙门氏菌属中增强胆汁抵抗力所必需的。

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As enteric pathogens, Salmonella spp. are resistant to the actions of bile. Salmonella typhimurium andSalmonella typhi strains were examined to better define the bile resistance phenotype. The MICs of bile for wild-typeS. typhimurium and S. typhi were 18 and 12%, respectively, and pretreatment of log-phase S. typhimurium with 15% bile dramatically increased bile resistance. Mutant strains of S. typhimurium andS. typhi lacking the virulence regulator PhoP-PhoQ were killed at significantly lower bile concentrations than wild-type strains, while strains with constitutively active PhoP were able to survive prolonged incubation with bile at concentrations of >60%. PhoP-PhoQ was shown to mediate resistance specifically to the bile components deoxycholate and conjugated forms of chenodeoxycholate, and the protective effect was not generalized to other membrane-active agents. Growth of both S. typhimurium and S. typhi in bile and in deoxycholate resulted in the induction or repression of a number of proteins, many of which appeared identical to PhoP-PhoQ-activated or -repressed products. The PhoP-PhoQ regulon was not induced by bile, nor did any of the 21 PhoP-activated or -repressed genes tested play a role in bile resistance. However, of the PhoP-activated or -repressed genes tested, two (prgC andprgH) were transcriptionally repressed by bile in the medium independent of PhoP-PhoQ. These data suggest that salmonellae can sense and respond to bile to increase resistance and that this response likely includes proteins that are members of the PhoP regulon. These bile- and PhoP-PhoQ-regulated products may play an important role in the survival of Salmonella spp. in the intestine or gallbladder.
机译：作为肠道病原体，沙门氏菌 spp。抵抗胆汁的作用。检查了鼠伤寒沙门氏菌和鼠伤寒沙门氏菌菌株，以更好地定义胆汁抵抗性表型。野生型 S的胆汁MIC。鼠伤寒和 S。对数期 S的预处理分别使伤寒和18虫分别占18％和12％。含15％胆汁的鼠伤寒显着提高了胆汁抵抗力。 S的突变株。鼠伤寒和 S。缺乏毒力调节剂PhoP-PhoQ的伤寒菌在比野生型菌株低得多的胆汁浓度下被杀死，而具有组成型活性PhoP的菌株能够在浓度> 60％的胆汁中长时间孵育。已显示PhoP-PhoQ介导对胆汁成分脱氧胆酸盐和鹅脱氧胆酸盐的共轭形式的特异性抗性，并且该保护作用并未推广到其他膜活性剂。两个 S的生长。鼠伤寒和 S。胆汁和脱氧胆酸盐中的鼠伤寒导致多种蛋白的诱导或抑制，其中许多蛋白看起来与PhoP-PhoQ激活或抑制的产物相同。 PhoP-PhoQ regulon不受胆汁诱导，测试的21种PhoP激活或抑制基因均未在胆汁抗性中发挥作用。但是，在测试的PhoP激活或抑制基因中，有两个（ prgC 和 prgH ）在不依赖PhoP-PhoQ的培养基中被胆汁转录抑制。这些数据表明沙门氏菌可以感知并响应胆汁以增加抵抗力，并且这种反应可能包括作为PhoP regulon成员的蛋白质。这些受胆汁和PhoP-PhoQ调节的产物可能在沙门氏菌（Salmonella spp）的存活中起重要作用。在肠或胆囊中。

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