GENETIC REGULATION OF THE TWIN ARGININE TRANSLOCATION SYSTEM IN SALMONELLA ENTERICA SEROVAR TYPHIMURIUM

鼠伤寒沙门氏菌双精氨酸易位系统的遗传调控

• 批准号: 9924230
• 负责人: Jeremy Ryan Ellermeier
• 金额: $ 7.5万
• 依托单位: MIDWESTERN UNIVERSITY (GLENDALE AZ)
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-06-19 至 2020-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9924230
• 关键词: Ampicillin; Antibiotics; Archaea; Arginine; Bacteria; Bile fluid; Cause of Death; Centers for Disease Control and Prevention (U.S.); Cessation of life; Cytoplasm; Disease; Elements; Enterobacteriaceae; Epidemic; Gastroenteritis; Genetic; Gram-Negative Bacteria; Hydrogenase; LacZ Genes; Life; Mus; Organism; Peptidoglycan; Plants; Protein Secretion; Proteins; Publishing; Regulation; Research; Resistance; Salmonella; Salmonella enterica; Stimulus; System; Systemic infection; Twin Multiple Birth; Typhoid Fever; United States; Virulence; Work; amidase; bile salts; combat; foodborne illness; human model; non-typhoidal Salmonella; pathogen; pathogenic bacteria; periplasm; pressure; promoter

Project Summary Salmonella species cause a range of diseases, from self-limiting gastroenteritis to life-threatening systemic infections, in a variety of hosts. The CDC estimates that non-typhoid Salmonella species cause 1.2 million cases of foodborne illness and 450 deaths per year in the United States alone. Salmonella enterica serovar Typhimurium is a leading cause of gastroenteritis worldwide and is used as a model for human typhoid fever in mice. The twin arginine translocation system (Tat) is a protein secretion system that is conserved in bacteria, archaea, and plants. In gram-negative bacteria, it is required for the export of substrate proteins from the cytoplasm to the periplasm of the organism. Tat substrates typically must be properly folded prior to export to the periplasm. In Salmonella, there are about 30 proteins that are substrates of Tat, among these are hydrogenases and amidases. While several studies have demonstrated that Tat is required for virulence in Salmonella and other bacterial pathogens, no published work has shown regulation of the system and tatABC is thought to be constitutively expressed. We have demonstrated that increasing concentrations of bile induce expression of a tatABC-lacZ fusion. Addition of 9% bile salt to LB media induces tatABC-lacZ about three-fold. We also have found that deletions of tatABC are more sensitive than wild type to peptidoglycan targeting antibiotics, though the addition of ampicillin does not activate expression of tatABC-lacZ. These finding leads to several questions: What is the mechanism of bile activation of tat expression? What promoter elements are important for expression of tatABC?

项目摘要 沙门氏菌引起一系列疾病，从自限性胃肠炎到危及生命的全身性 感染，在各种宿主中。疾病预防控制中心估计，非伤寒沙门氏菌物种造成120万 仅在美国每年就有450例食源性疾病和450例死亡。肠道沙门氏菌伤寒血清变型 鼠伤寒是世界范围内胃肠炎的主要原因， 小鼠双精氨酸易位系统（达特）是细菌中保守的蛋白质分泌系统， 古细菌和植物。 在革兰氏阴性菌中，它是将底物蛋白从细胞质输出到周质所必需的 生物体。达特底物通常必须在输出到周质之前正确折叠。沙门氏菌， 大约有30种蛋白质是达特的底物，其中有氢化酶和酰胺酶。而 几项研究表明，达特是沙门氏菌和其他细菌的毒力所必需的 病原体，没有发表的工作表明该系统的调节和tatABC被认为是组成性的 表达。我们已经证明，增加胆汁浓度诱导tatABC-lacZ的表达， 核聚变在LB培养基中加入9%胆汁盐诱导tatABC-lacZ约3倍。我们还发现， tatABC的缺失比野生型对肽聚糖靶向抗生素更敏感，尽管添加了tatABC， 氨苄青霉素不能激活tatABC-lacZ的表达。这些发现引出了几个问题： 胆汁激活达特表达的机制？哪些启动子元件对于表达 tatABC？