An essential feature of the pathogenesis of the Salmonella enterica serovar Enteritidis wild type (WT) is its ability to survive under diverse microenvironmental stress conditions, such as encountering antimicrobial peptides (AMPs) or glucose and micronutrient starvation. These stress factors trigger virulence genes carried on Salmonella pathogenicity islands (SPIs) and determine the efficiency of enteric infection. Although the oligosaccharide/oligonucleotide binding-fold (OB-fold) family of proteins has been identified as an important stress response and virulence determinant, functional information on members of this family is currently limited. In this study, we decipher the role of YdeI, which belongs to OB-fold family of proteins, in stress response and virulence of S. Enteritidis. When ydeI was deleted, the ΔydeI mutant showed reduced survival during exposure to AMPs or glucose and Mg²⁺ starvation stress compared to the WT. Green fluorescent protein (GFP) reporter and quantitative real-time PCR (qRT-PCR) assays showed ydeI was transcriptionally regulated by PhoP, which is a major regulator of stress and virulence. Furthermore, the ΔydeI mutant displayed ∼89% reduced invasion into HCT116 cells, ∼15-fold-reduced intramacrophage survival, and downregulation of several SPI-1 and SPI-2 genes encoding the type 3 secretion system apparatus and effector proteins. The mutant showed attenuated virulence compared to the WT, confirmed by its reduced bacterial counts in feces, mesenteric lymph node (mLN), spleen, and liver of C57BL/6 mice. qRT-PCR analyses of the ΔydeI mutant displayed differential expression of 45 PhoP-regulated genes, which were majorly involved in metabolism, transport, membrane remodeling, and drug resistance under different stress conditions. YdeI is, therefore, an important protein that modulates S. Enteritidis virulence and adaptation to stress during infection.

中文翻译：

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OB折叠蛋白YdeI在肠炎沙门氏菌肠炎沙门氏菌应激反应和毒力中的作用

所述的发病机理的主要特征肠沙门氏菌血清变型肠炎野生型（WT）是其不同的微环境胁迫条件下，例如遇到的抗微生物肽（AMP）或葡萄糖和微量营养素饥饿下存活的能力。这些压力因素触发沙门氏菌致病岛（SPIs）上携带的毒力基因，并确定肠道感染的效率。尽管蛋白质的寡糖/寡核苷酸结合倍数（OB-fold）家族已被确定为重要的应激反应和毒力决定因素，但目前对该家族成员的功能信息仍然有限。在这项研究中，我们破译了蛋白质的OB折叠家族的YdeI在应激反应和毒力中的作用。小号。肠炎。当ydeI缺失时，与WT相比，ΔydeI突变体在暴露于AMPs或葡萄糖和Mg ²⁺饥饿胁迫期间显示出降低的存活率。绿色荧光蛋白（GFP）报告基因和定量实时PCR（qRT-PCR）分析表明ydeI受PhoP转录调节，而PhoP是压力和毒力的主要调节剂。此外，ΔydeI该突变体显示出对HCT116细胞的侵袭降低了约89％，巨噬细胞内存活率降低了约15倍，并且下调了一些编码3型分泌系统装置和效应蛋白的SPI-1和SPI-2基因。与WT相比，该突变体显示出减弱的毒力，这是由C57BL / 6小鼠粪便，肠系膜淋巴结（mLN），脾脏和肝脏中细菌数量减少所证实的。ΔydeI突变体的qRT-PCR分析显示了45个PhoP调控基因的差异表达，这些基因主要参与不同胁迫条件下的代谢，转运，膜重塑和耐药性。因此，YdeI是调节S的重要蛋白质。肠炎毒力和感染期间适应压力的能力。