伤寒沙门菌yncD基因参与铁摄取的功能研究

项目名称： 伤寒沙门菌yncD基因参与铁摄取的功能研究

项目编号： No.31500116

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 生物科学

项目作者： 熊坤

作者单位： 中国人民解放军第三军医大学

项目金额： 20万元

中文摘要： 铁是细菌赖以生存的必需元素。革兰阴性菌主要通过释放铁载体从环境中竞争获取铁元素，结合了铁的铁载体向细菌胞内转运铁时需要外膜上TonB依赖性转运蛋白（TBDTs）介导， TBDTs对病原菌在体内的生存和致病至关重要。课题组在前期研究中，筛选并鉴定了一个新的伤寒沙门菌毒力基因yncD，将其敲除后会导致细菌在小鼠体内的生存能力和毒力显著降低低。生物信息学分析显示YncD具有典型的TBDT结构特征，三价铁促生长实验也初步证实yncD基因与铁摄取有关。为深入探讨yncD基因的功能，本项目拟在构建了yncD基因敲除株和回补株的基础上，进一步通过放射性铁元素摄取实验、YncD依赖性铁载体的分离鉴定，以及YncD与TonB蛋白的相互作用及其作用位点分析等研究揭示YncD在伤寒沙门菌铁摄取和致病过程中的作用，为深入认识伤寒沙门菌的铁摄取机制及致病机理奠定理论基础，并为伤寒新型减毒疫苗的研制提供新的靶标。

中文关键词： 伤寒沙门菌；基因功能；铁载体；铁摄取；TonB依赖性转运蛋白

英文摘要： Iron is an essential element for bacterial survival. For Gram-negative bacteria, the transportation of siderophores across outer membrane is mediated by TonB-dependent transporter (TBDT). Previous studies have shown that these TBDTs play a key role in bacterial survival and pathogenesis in vivo. In our previous study of Salmonella Typhi, we screened and identified a noval virulence gene, yncD gene. Deletion of yncD gene led to significant decrease in survival ability and virulence of S. Typhi. Bioinformatics analysis of YncD revealed typical structural features of TBDT. A ferric iron growth-promoting experiment in iron-limited media preliminarily confirmed that the YncD involves in bacterial iron uptake. Based on these works, in this project, we intend to verify the function of yncD gene by performing experiments of radioactive iron uptake, isolation and identification of its siderophore substrate and analyzing the interaction of YncD and TonB. And we also intend to analyze the role that YncD play in the pathogenesis of S. Typhi. The results of our research will provide new ideas for the understanding of typhoid pathogenesis and lay a foundation for the future application of yncD gene in developing typhoid vaccine.

英文关键词： Salmonella Typhi;gene function;siderophore;Iron untake;TonB-dependent transporter