ACID-BASE PHYSIOLOGY OF ORAL STREPTOCOCCI

口腔链球菌的酸碱生理学

• 批准号: 2129316
• 负责人: ROBERT E MARQUIS
• 金额: $ 16.04万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 1983
• 资助国家: 美国
• 起止时间: 1983-03-01 至 1996-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2129316
• 关键词: Actinomyces; Lactobacillus casei; Streptococcus mutans; Streptococcus sanguis; acid base balance; adenosinetriphosphatase; dental plaque; enzyme complex; enzyme reconstitution; glucose; glycolysis; hydrogen; hydrogen transport; ion transport; lactates; liposomes; membrane transport proteins; microorganism culture; oral bacteria; phospholipids; potassium; protein purification; sodium

This application is for support of a project focused on the acid-base physiology of selected bacteria from dental plaque, specifically Lactobacillus casei, Streptococcus mutans, Streptococcus sanguis and Actinomyces viscosus. These organisms were chosen to represent a wide range of acid tolerance from the highly tolerant L. casei to the relatively intolerant A. viscosus. A basic premise of the project is that acid tolerance is directly related to cariogenicity. To be cariogenic, a plaque bacterium must first colonize and become a significant member of the flora. It must then produce acid rapidly from dietary or salivary, sugars. It must be able to carry out glycolysis at the low pH values in plaque that lead to demineralization. The minimum pH value in cariogenic plaque is somewhat less than 4, and it is only the more acid-tolerant organisms that are active in this acid environment, especially the mutans streptococci, but also Lactobacillus organisms. The challenge to tooth integrity is related to the total time of acidification and to the extent of acidification during the acid-base cycles of plaque. An important part of the proposal concerns the abilities of cariogenic bacteria to adapt to acid environments and the mechanisms of adaptation. Preliminary results indicate that phenotypic adaptation does occur in chemostat culture and involves increased activity of F1F0 proton translocating ATPases. Adaptation results in acquired ability to carry out glycolysis at lower pH values. Thus, not only is acid tolerance a cariogenic attribute, but ability to adapt to acid environments may enhance cariogenicity. The major player in acid tolerance appears to be the FlF0 ATPase of cell membranes, and much of the proposed work is on basic enzymology, including isolation and purification of Fl and F0 sectors, separation of sector components, reconstitution of enzymes on membranes, in solution and in liposomes. Work is planned also on secondary systems involved in proton currents across the membrane, especially potassium transporters and proton-organic-acid symporters. The net result of the proposed work and related genetic work will be a clearer picture of the acid-base physiology of cariogenic plaque bacteria, and hopefully, ways to reduce the cariogenicity of plaque.

该应用程序是为了支持一个专注于该项目 牙菌斑中选定细菌的酸碱生理， 特异性乳酸杆菌，链球菌突变，链球菌 Sanguis和放线菌Viscosus。 这些生物被选为 来自高耐受性L。代表广泛的酸耐受性。 相对不宽容的A. viscosi。 一个基本前提 项目是酸的耐受性与致癌性直接相关。 到 是致癌的，斑块细菌必须首先定居并成为一个 菌群的重要成员。 然后必须从 饮食或唾液，糖。 它必须能够在 斑块中的低pH值导致脱矿化。 最小值 pH值的pH值略小于4，只有 在这种酸环境中活跃的更多耐酸的生物， 尤其是突变体链球菌，也是乳酸菌生物。 牙齿完整性面临的挑战与总时间有关 酸化和酸碱酸化的程度 斑块周期。 提案的重要部分是 致癌细菌适应酸环境和机制 适应。 初步结果表明表型适应确实 发生在化学仪培养中，涉及F1F0质子的活性增加 易位ATPases。 适应导致获得的能力 在较低的pH值下糖酵解。 因此，不仅酸耐受性A 致癌属性，但是适应酸环境的能力可能 增强创核性。 酸耐受性的主要参与者似乎是 细胞膜和拟议的大部分工作都是关于基本酶学的， 包括隔离和纯化FL和F0扇区，分离 部门成分，膜上酶的重构，解决方案 和脂质体。 还计划在涉及的二级系统上进行工作 跨膜，尤其是钾转运蛋白的质子电流 和质子和有机酸的分类剂。 拟议工作和相关遗传工作的最终结果将是 致癌斑块的酸碱生理学的清晰图片 细菌，并希望能降低斑块的致牙作用。