Contribution of the Streptococcus mutans cid and lrg Murein Hydrolase Regulator H

变形链球菌 cid 和 lrg Murein 水解酶调节剂 H 的贡献

• 批准号: 7660922
• 负责人: Kelly Christine Rice
• 金额: $ 10.8万
• 依托单位: UNIVERSITY OF FLORIDA
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-06-01 至 2011-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7660922
• 关键词: Acids; Adherence; Adult; Alleles; Autolysis; Bacteria; Bacterial Physiology; Biological Assay; Blood Circulation; Cell Death; Cells; Child; Chronic Disease; Clinical; Communities; Complement; Confocal Microscopy; Cytolysis; DNA; Dental; Dental Plaque; Dental caries; Development; Disease; Endocarditis; Fluorescence; Galactosidase; Genes; Genetic; Genome; Genomics; Goals; Heart Valves; Homologous Gene; Infection; Infective endocarditis; Laboratories; Measures; Mediating; Membrane Potentials; Metabolic; Microarray Analysis; Microbial Biofilms; Modeling; Molecular; Monitor; Mutation; N-Acetylmuramoyl-L-alanine Amidase; Northern Blotting; Pathogenesis; Patients; Physiological Processes; Physiology; Pit and Fissure Sealants; Prevention strategy; Process; Regulation; Regulator Genes; Research; Research Project Grants; Risk; Role; Schools; Signal Transduction; Staphylococcus aureus; Streptococcus mutans; System; Techniques; Testing; Time; Toothbrushing; Virulence; Water fluoridation; antimicrobial; base; drinking water; extracellular; improved; microorganism; novel; oral streptococci; pathogen; programs; promoter; public health relevance; tooth surface; toothbrush; treatment strategy

DESCRIPTION (provided by applicant): Streptococcus mutans is the primary causative agent of dental caries, which remains the most common chronic disease among children and is untreated in up to 30% of adults over 35 yrs-old. When transiently introduced into the bloodstream following daily dental hygienic practices such as tooth brushing and flossing, this bacterium can also cause potentially lethal endocarditis infections in atrisk patients. S. mutans virulence is intimately related to its ability to form biofilm, but the molecular mechanisms facilitating its initial attachment to the tooth surface, as well as biofilm maturation and dispersal, are not well understood. In this respect, cell death and lysis are aspects of bacterial physiology that have been implicated in S. mutans biofilm formation. Although well-studied in other microorganisms, the molecular mechanisms that regulate cell death and autolysis in S. mutans have not been clearly defined. To this end, a developmental research project is proposed that initiates study of the cid and lrg genes in S. mutans, as these genes have been shown to be important regulators of cell death, autolysis and biofilm development in the pathogen Staphylococcus aureus. The specific aims of this application are (1) to ascertain the role of the cid and lrg genes in regulating S. mutans cell death and lysis during biofilm development, and (2) to examine the genetic and metabolic factors that control expression of the cid and lrg genes in S. mutans. Allele replacement mutations will be created in the cid, lrg, and lytS genes in both laboratory and clinical S. mutans strains. The effect of these mutations on cell death and lysis will be measured by a variety of phenotypic assays. Confocal microscopy will be used to assess their effect on biofilm adherence and development in flow cell and static models, as well as to monitor fluorescence of cid and lrg GFP promoter fusions. The role of metabolic signals and the lytS gene on cid and lrg expression will also be assessed. It is anticipated that this research will delineate a critical aspect of S. mutans physiology and pathogenesis that will help improve strategies of prevention and treatment of dental caries, as well as infective endocarditis. This research is also an important first step in achieving the long-term goal of defining the mechanisms that control cell death and autolysis in the oral streptococci, and how these processes contribute to their ability to grow and survive in dental plaque as well as their ability to colonize heart valves during endocarditis. PUBLIC HEALTH RELEVANCE: Despite wide-spread implementation of preventative measures such as community water fluoridation and school-based dental sealant programs, dental caries remains the most common chronic disease among children, and is also prevalent among adults. Streptococcus mutans, the bacteria that causes dental caries, can also cause infective endocarditis in at-risk patients. Therefore, research that contributes to our understanding of how this pathogen is able to colonize and grow in dental plaque will facilitate the development of novel preventative and/or treatment strategies for both of these diseases.

描述（由申请人提供）：变形链球菌是龋齿的主要病原体，龋齿仍然是儿童中最常见的慢性疾病，在35岁以上的成年人中，高达30%的人未经治疗。当在刷牙和使用牙线等日常牙齿卫生习惯后短暂进入血液时，这种细菌也可能在高危患者中引起潜在致命的心内膜炎感染。S.变形菌的毒力与其形成生物膜的能力密切相关，但促进其最初附着于牙齿表面以及生物膜成熟和扩散的分子机制尚不清楚。在这方面，细胞死亡和溶解是细菌生理学的方面，与沙门氏菌有关。变形菌生物膜形成。尽管在其他微生物中已经得到了很好的研究，但在S。变异体还没有明确定义。为此，提出了一个开发性研究项目，启动了对S.这些基因在病原体金黄色葡萄球菌（Staphylococcus aureus）中是细胞死亡、自溶和生物膜发育的重要调节因子。本申请的具体目的是（1）确定cid和lrg基因在调节S.生物膜形成过程中变形链球菌细胞死亡和裂解的影响，以及（2）检测控制变形链球菌cid和lrg基因表达的遗传和代谢因素。变异人在实验室和临床S.变异株这些突变对细胞死亡和裂解的影响将通过多种表型测定来测量。共聚焦显微镜将用于评估其对流动池和静态模型中生物膜粘附和发展的影响，以及监测cid和lrg GFP启动子融合的荧光。还将评估代谢信号和lytS基因对cid和lrg表达的作用。预计这项研究将描绘一个重要方面的S。变形菌的生理和发病机制，这将有助于改善预防和治疗龋齿的策略，以及感染性心内膜炎。这项研究也是实现长期目标的重要第一步，即确定控制口腔链球菌细胞死亡和自溶的机制，以及这些过程如何有助于它们在牙菌斑中生长和存活的能力以及它们在心内膜炎期间定植心脏瓣膜的能力。 公共卫生相关性：尽管广泛实施了预防措施，如社区饮水加氟和以学校为基础的牙齿密封剂计划，但龋齿仍然是儿童中最常见的慢性疾病，在成年人中也很普遍。变形链球菌是引起龋齿的细菌，也会引起高危患者的感染性心内膜炎。因此，有助于我们了解这种病原体如何能够在牙菌斑中定植和生长的研究将促进这两种疾病的新型预防和/或治疗策略的发展。