DETERMINATION OF THE ROLE OF Smu.833 IN THE FITNESS AND VIRULENCE OF CARIOGENIC STREPTOCOCCUS MUTANS

测定 Smu.833 在致龋性变形链球菌的适应性和毒力中的作用

• 批准号: 9171316
• 负责人: Katherine L. Rainey
• 金额: $ 4.44万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9171316
• 关键词: Adherence; Alabama; Bacteria; Bacterial Adhesins; Binding; Binding Proteins; Biological Assay; Caries prevention; Cell Fraction; Child; Collaborations; Collagen; Communicable Diseases; Complement; Complex; Data; Dental Enamel; Dental caries; Diet; Dietary Sucrose; Dietary Sugars; Disease; Eating; Elderly; Environment; Enzymes; Gel; Genes; Genetic; Glucans; Glucose; Glucosyltransferases; Goals; Health; Homologous Gene; Hydrogen Peroxide; Impairment; In Vitro; Infective endocarditis; Intake; Lactic acid; Length; Mass Spectrum Analysis; Metabolism; Microbial Biofilms; Modeling; Modification; Nutritional; Oral cavity; Oxidative Stress; Pain; Parents; Pathway interactions; Phenotype; Play; Population; Prevalence; Production; Proteins; Proteomics; Rattus; Regulation; Research; Role; Science; Serotyping; Streptococcus mutans; Surface; Testing; Therapeutic Uses; Universities; Virulence; Virulence Factors; bacterial fitness; commensal microbes; demineralization; effective therapy; extracellular; fitness; genetic regulatory protein; genome-wide; glucosyltransferase B; glycosylation; glycosyltransferase; in vivo Model; interest; killings; mutant; new therapeutic target; oral commensal; oral pathogen; pathogenic bacteria; polymerization; protein profiling; protein protein interaction; targeted treatment; therapeutic target; tooth surface

 DESCRIPTION (provided by applicant): Dental caries, more commonly known as tooth decay, is the most common infectious disease worldwide and is increasing in prevalence among young children despite advancements in caries research. Untreated cavities can cause severe pain and impairment of eating, leading to reduced nutritional intake and diet-related ill health especially for children and the elderly. The main etiological agent of dental caries is Streptococcus mutans which can readily form a biofilm on the surface of teeth and produce lactic acid through the metabolism of dietary sugars which is largely responsible for the demineralization and subsequent destruction of tooth enamel. In addition, S. mutans synthesizes extracellular glucosyltransferases (Gtfs) capable of breaking apart dietary sucrose and polymerizing the glucose subunits into the sticky glucan matrix of the biofilm, imperative for the formation of robust, three-dimensional biofilms. Currently used caries therapies are not species-specific and kill pathogenic species as well as commensal species which are protective against the formation of pathogenic biofilms. There are a number of proteins in S. mutans whose function remains unknown but which could present new targets for S. mutans specific anti-caries treatment. One such protein is a conserved, putative glycosyltransferase encoded by the gene smu.833 in S. mutans strain UA159. A homologue of Smu.833 in a different serotype of S. mutans, has been shown to glycosylate an important surface collagen binding protein important for bacterial colonization in infective endocarditis. Thus, this protein makes a good candidate to be studied and analyzed for its potential as a target for caries therapies. In order o characterize this protein in S. mutans, we created a deletion mutant and assayed for phenotypic changes in bacterial fitness and virulence. Initial studies revealed decreased levels of Gtfs and subsequent glucan matrix formation within the mutant, as well as additional intriguing phenotypes including increased bacterial chain length and aggregation, increased sensitivity to oxidative stress, and increased levels of biofilm regulatory protein. The results obtained thus far have led to the hypothesis that Smu.833 is required both for Gtf glycosylation and stability and for an additional role in S. mutans which more globally effects bacterial fitness and virulence. To test this hypothesis, we propose three specific aims: Aim 1: Determine the role of Smu.833 in Gtf expression; Aim 2: Determine the global role Smu.833 plays in bacterial fitness and virulence ; Aim 3: Determine the effect of Smu.833 on bacterial competitiveness. Elucidating the role of Smu.833 in S. mutans will help unravel the complex interactions that govern the fitness and virulence of this bacterium. Furthermore, results from this application may present a new species-specific target for therapeutics used in the prevention of dental caries, a costly and painful disease which effects the vast majority of the world's population.

 描述（由适用提供）：龋齿（通常称为牙齿衰减）是全球最常见的感染，尽管有研究的进步，但幼儿的患病率正在增加。未经处理的腔体会导致严重的疼痛和饮食障碍，从而减少营养摄入量和与饮食有关的健康状况，特别是对于儿童和老年人。龋齿的主要病因是链球菌突变，可以通过饮食中的饮食糖代谢在牙齿表面上很容易形成生物膜，并产生乳酸，这在很大程度上是造成债务和随后破坏牙齿搪瓷的原因。此外，链球菌合成了细胞外葡萄糖基转移酶（GTFS），能够分解饮食中的蔗糖并将葡萄糖亚基分解为生物膜的粘性谷物基质中，这对于鲁棒，三维生物生物生物生物生物生物生物生物生物生物生物生物生物生物生物形成势在必行。目前使用的疗法不是物种特异性的，杀死了致病物种，也是保护病原生物膜形成的共生物种。 S. mutans中有许多蛋白质的功能尚不清楚，但可能会为特定于抗野菜的链球菌提供新的靶标。一种这样的蛋白质是一种保守的，推定的糖基转移酶，该蛋白由smu.833在链球菌菌株UA159中编码。 SMU的同源物833在不同的突变链球菌血清型中，已被证明是糖基化的一种重要的表面胶原蛋白结合蛋白，对感染性心内膜炎中细菌定植很重要。这是该蛋白质成为一个很好的候选者，以研究和分析其作为汽车疗法的靶标的潜力。为了表征该蛋白在链球菌中，我们创建了一个缺失突变体，并测定了细菌适应性和病毒的表型变化的测定。最初的研究表明，突变体内GTF的水平下降以及随后的谷物基质形成，以及其他有趣的表型，包括增加细菌链长度和聚集，对氧化应激的敏感性提高以及生物膜调节蛋白的敏感性增加。到目前为止获得的结果 已经提出了以下假设，即SMU.833既需要GTF糖基化和稳定性，又需要在全球链球菌中发挥额外的作用，该螺旋杆菌在全球范围内影响细菌的适应性和病毒。到 检验该假设，我们提出了三个具体目标：目标1：确定SMU.833在GTF表达中的作用；目标2：确定全球作用SMU.833在细菌健身和病毒中发挥作用；目标3：确定SMU.833对细菌竞争力的影响。阐明SMU的作用833在S. mutans中将有助于揭示控制该细菌的适应性和病毒的复杂相互作用。此外，该应用的结果可能会呈现出针对预防牙齿携带的新物种特异性治疗的靶标，这是一种昂贵而痛苦的疾病，影响了世界绝大多数人口。