Characterization of Clostridium difficile spore germination

艰难梭菌孢子萌发的表征

• 批准号: 8893193
• 负责人: Joe Sorg
• 金额: $ 32.39万
• 依托单位: TEXAS A&M UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2015-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8893193
• 关键词: Air; Amino Acids; Anaerobic Bacteria; Antibiotic Resistance; Antibiotics; Appearance; Bacteria; Bile Acids; Binding; Binding Proteins; Biological Assay; Calorimetry; Cells; Chenodeoxycholic Acid; Cholesterol; Cholic Acids; Clostridium difficile; Computer Simulation; Deposition; Diarrhea; Diffusion; Disease; Environment; Enzymes; Excretory function; Exposure to; Gallbladder; Gastrointestinal tract structure; Genetic Screening; Germination; Glycine; Goals; Growth; Health; Healthcare; Healthcare Systems; Homologous Gene; Hospitals; Human; Immunocompromised Host; In Vitro; Infection; Investigation; Knowledge; Lead; Ligands; Liver; Location; Mediating; Membrane; Molecular; Molecular Target; Morbidity - disease rate; Osmolar Concentration; Pathogenesis; Patients; Peptide Hydrolases; Peptidoglycan; Phase; Production; Proteins; Pyroxylin; Reaction; Reporting; Reproduction spores; Risk; Role; Signal Transduction; Site; Staging; Surface; Symptoms; Taurine; Taurocholic Acid; Testing; Titrations; Toxin; Translating; United States; Water; Work; analog; base; combat; cost; design; hydroxyl group; in vivo; inhibitor/antagonist; mortality; mutant; novel; novel therapeutics; receptor; research study

DESCRIPTION (provided by applicant): Clostridium difficile is the leading cause of antibiotic-associated diarrhea in the hospital and long term health care settings. In addition to the patient toll, the treatment-associated costs of C. difficile infections to the United States healthcare system have been estimated at $3.2 billion. Although the rate of C. difficile infection in the United States is rising, surprisingly little is known about the mechanisms of C. difficile pathogenesis. C. difficile is believed to be acquired by the host in the form of a dormant spore. To cause disease, the spore must respond in the gastrointestinal tract to signals that trigger germination, thereby allowing growth as a vegetative bacterium, toxin production and subsequent spore formation before excretion into the environment. We have shown that taurocholic acid, a bile acid normally found in the GI tract, and glycine are co-germinants for C. difficile spores. Another bile acid, chenodeoxycholic acid, inhibits taurocholic acid-mediated germination and is toxic for C. difficile vegetative growth. We recently identified the molecular target of bile acids on the C. difficile spore thus identifying the first C. difficile spore germinnt receptor. Our long-term goal is to understand the molecular mechanisms of C. difficile germination and use that knowledge to rationally design inhibitors of C. difficile infection. In ths proposal, we propose to: (1) identify how the C. difficile spore germinant receptor interacts with bile acids; (2) identify binding partners and the ultrastructural location of the germinant recepto in the C. difficile spore; and (3) identify other C. difficile germinant receptors. Successful completion of the experiments outlined herein will extend our understanding of the mechanisms of C. difficile germination, open new avenues in the study of C. difficile spore formation and spore germination and lead to the identification of homologs of the newly discovered germinant receptors in other spore-forming bacteria (opening other avenues of investigation).

描述（由申请人提供）：艰难梭菌是医院和长期卫生保健机构抗生素相关性腹泻的主要原因。除了患者死亡人数外，艰难梭菌感染给美国医疗保健系统带来的治疗相关费用估计为32亿美元。尽管艰难梭菌在美国的感染率正在上升，但令人惊讶的是，人们对艰难梭菌的发病机制知之甚少。艰难梭菌被认为是由宿主以休眠孢子的形式获得的。要引起疾病，孢子必须在胃肠道中对触发发芽的信号作出反应，从而允许作为营养细菌生长，产生毒素和随后的孢子形成，然后排泄到环境中。我们已经证明牛磺胆酸（一种通常在胃肠道中发现的胆汁酸）和甘氨酸是艰难梭菌孢子的共同生发物。另一种胆汁酸，鹅去氧胆酸，抑制牛磺胆酸介导的发芽，对艰难梭菌的营养生长有毒。我们最近确定了胆汁酸在艰难梭菌孢子上的分子靶点，从而鉴定了第一个艰难梭菌孢子萌发受体。我们的长期目标是了解艰难梭菌萌发的分子机制，并利用这些知识来合理设计艰难梭菌感染的抑制剂。在本提案中，我们建议：(1)确定艰难梭菌孢子萌发受体如何与胆汁酸相互作用；(2)鉴定艰难梭菌孢子中结合伙伴和萌发受体的超微结构位置；(3)鉴定其他艰难梭菌发芽受体。本文所述实验的成功完成将扩展我们对艰难梭菌萌发机制的理解，为艰难梭菌孢子形成和孢子萌发的研究开辟新的途径，并导致在其他孢子形成细菌中鉴定新发现的萌发受体的同源物（开辟其他研究途径）。