MICROBIOLOGIC STUDIES OF HUMAN ORAL STREPTOCOCCI

人类口腔链球菌的微生物学研究

• 批准号: 3218828
• 负责人: BURTON ROSAN
• 金额: $ 23.54万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 1977
• 资助国家: 美国
• 起止时间: 1977-07-01 至 1996-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3218828
• 关键词: Streptococcus sanguis; adhesin; cell adhesion molecules; conformation; endopeptidases; enzyme mechanism; hydroxyapatites; immunochemistry; molecular cloning; pellicle; protein degradation; protein purification; protein structure function; saliva; site directed mutagenesis

Streptococcus sanguis plays a central role in dental plaque formation because of its high affinity for salivary pellicle and its ability to interact with other organisms. An adhesin, designated the A antigen, has been shown to be directly correlated with the attachment of S. sanguis G9B to saliva coated hydroxyapatite (SHA) which is an accepted model for the salivary pellicle. The adhesin is a protein or possibly a glycoprotein and is composed of three polypeptides whose molecular weights are 80, 62 and 52 kDa (the 80 kDa antigen complex). Antibody against the A antigen or the native 80 kDa inhibits attachment of G9B to SHA. Although antibody to the denatured 80 kDa protein reacts with the 80 kDa antigen complex, it does not react with the A antigen nor does it inhibit attachment. These properties suggest that adhesion to SHA is associated with conformational rather than sequential epitopes. Regulation of adhesin activity may be associated with an adhesin protease which was also found in S. sanguis. The objectives of the proposed studies are to determine the function domains of the adhesin and the role of the adhesin protease in governing the ability of S. sanguis strains to attach to salivary pellicle. The studies will utilize a combination of biochemical, immunological and molecular biological approaches to characterize the functional domains of the adhesin molecules. In order to accomplish the latter goal a genomic library of the chromosome of G9B has been constructed in Escherichia coli using an EMBL3 vector. The biological role of the protease in regulating ecological interactions will be explored by creating a protease deficient mutant of G9B by insertional inactivation of the protease gene isolated from this library. Control of dental plaque formation has become a central tenet in new approaches to the reduction of dental caries and periodontal disease. It has become clear that shotgun approaches to controlling plaque formation often results in unwanted side effects and therefore attention has been focused on mechanisms of specifically controlling this process. An understanding of the mechanisms of interaction between the bacterial surface polymers and the salivary proteins involved is the first step in developing biological and chemotherapeutic agents for regulating initial events in dental plaque formation.

血链球菌在牙菌斑形成中发挥核心作用 因为它对唾液膜具有高亲和力并且能够 与其他生物体相互作用。 粘附素，称为 A 抗原，具有 已被证明与 S. sanguis G9B 的附着直接相关 唾液涂层羟基磷灰石（SHA），这是公认的模型 唾液膜。 粘附素是一种蛋白质或可能是一种糖蛋白并且 由分子量分别为80、62和52的三种多肽组成 kDa（80 kDa 抗原复合物）。 针对 A 抗原或 天然 80 kDa 抑制 G9B 与 SHA 的附着。 虽然抗体 变性的 80 kDa 蛋白质与 80 kDa 抗原复合物发生反应，它确实 不与 A 抗原发生反应，也不抑制附着。 这些 特性表明对 SHA 的粘附与构象有关 而不是连续的表位。 粘附素活性的调节可能是 与在血链球菌中也发现的粘附素蛋白酶有关。 拟议研究的目标是确定函数 粘附素的结构域以及粘附素蛋白酶在调控中的作用 血链球菌菌株附着于唾液膜的能力。 这 研究将结合生物化学、免疫学和 分子生物学方法来表征功能域 粘附素分子。 为了实现后一个目标，基因组 大肠杆菌G9B染色体文库已构建 使用 EMBL3 载体。 蛋白酶在调节中的生物学作用 将通过创建蛋白酶缺陷来探索生态相互作用 通过插入失活分离的蛋白酶基因产生 G9B 突变体 来自这个图书馆。 控制牙菌斑形成已成为核心 减少龋齿和牙周病新方法的宗旨 疾病。 很明显，鸟枪法可以控制牙菌斑 形成通常会导致不必要的副作用，因此应引起注意 一直专注于专门控制这一过程的机制。 了解细菌之间相互作用的机制 表面聚合物和所涉及的唾液蛋白是第一步 开发生物和化疗药物来调节初始 牙菌斑形成过程中的事件。