PDF(Pubmed)
Abstract：
Vibrio fluvialis is an emerging foodborne pathogenic bacterium that can cause severe cholera-like diarrhea and various extraintestinal infections, posing challenges to public health and food safety worldwide. The arginine deiminase (ADI) pathway plays an important role in bacterial environmental adaptation and pathogenicity. However, the biological functions and regulatory mechanisms of the pathway in V. fluvialis remain unclear. In this study, we demonstrate that L-arginine upregulates the expression of the ADI gene cluster and promotes the growth of V. fluvialis. The ADI gene cluster, which we proved to be comprised of two operons, arcD and arcACB, significantly enhances the survival of V. fluvialis in acidic environments both in vitro (in culture medium and in macrophage) and in vivo (in mice). The mRNA level and reporter gene fusion analyses revealed that ArgR, a transcriptional factor, is necessary for the activation of both arcD and arcACB transcriptions. Bioinformatic analysis predicted the existence of multiple potential ArgR binding sites at the arcD and arcACB promoter regions that were further confirmed by electrophoretic mobility shift assay, DNase I footprinting, or point mutation analyses. Together, our study provides insights into the important role of the ArgR-ADI pathway in the survival of V. fluvialis under acidic conditions and the detailed molecular mechanism. These findings will deepen our understanding of how environmental changes and gene expression interact to facilitate bacterial adaptations and virulence.
摘要：
弧菌是一种新兴的食源性致病菌，可引起严重的霍乱样腹泻和各种肠外感染，对全球公共卫生和食品安全构成挑战。精氨酸脱亚胺酶（ADI）途径在细菌环境适应和致病性中起重要作用。然而,该途径的生物学功能和调节机制尚不清楚。在这项研究中,我们证明L-精氨酸上调ADI基因簇的表达并促进河弧菌的生长。ADI基因簇，我们被证明是由两个操纵子组成的，arcD和arcACB，在体外（在培养基中和在巨噬细胞中）和体内（在小鼠中）均显着增强了河弧菌在酸性环境中的存活率。mRNA水平和报告基因融合分析显示ArgR，转录因子，是激活arcD和arcACB转录所必需的。生物信息学分析预测在arcD和arcACB启动子区域存在多个潜在的ArgR结合位点，这通过电泳迁移率变化分析进一步证实。DNaseI足迹，或点突变分析。一起,我们的研究提供了ArgR-ADI通路在酸性条件下的重要作用以及详细的分子机制。这些发现将加深我们对环境变化和基因表达如何相互作用以促进细菌适应和毒力的理解。
