Oxidative Stress in Oral Streptococci

描述(申请人提供)：拟议研究的长期目标是更全面地了解口腔链球菌的氧化应激和氧化损伤，并利用这些信息开发有效的抗菌剂来控制牙菌斑的致病性，主要与龋齿有关。该项目的具体目标如下。具体目标1侧重于更详细地确定变形链球菌对氧化应激的适应性反应。该定义将包括对引起反应的因素的确定，包括酸化，但特别是好氧生长和接触巯基试剂。确定这些反应的细节，特别是它们的生理调节，将取决于我们已经开发的遗传工具，包括保护酶和调节蛋白基因的突变。具体目标2涉及口腔链球菌呼吸的基础研究，特别是变形链球菌，包括直接从牙菌斑中分离的菌株，以及单一生物和混合生物生物膜的使用。另一部分目的是更详细地确定氧化损伤的主要细胞靶点，特别是蛋白质，并评估针对氧化应激的保护机制的能量学，其中大多数需要ATP、NADH和/或NADPH来发挥作用。具体目标3侧重于转化研究，调查小分子，如锌离子、苯并咪唑或其他巯基反应剂，如大蒜素、螯合剂、氟化物和其他卤素、过渡金属阳离子和氧化抗菌剂。这项研究将与前两个特定目标的基础研究密切交错，以期利用基本信息开发有效加强对口腔细菌氧化损害的试剂或药物组合。翻译工作将包括对单一生物和混合生物膜的研究，以及细胞/生物膜对测试抗菌剂的渗透性和保留力的测定，以帮助我们评估它们在口腔预防和治疗方面的潜力。这项研究与公共卫生直接相关，主要是对龋齿的控制。龋病是美国年轻人中最常见的传染病，也是美国老年人面临的日益严重的问题。这项工作涉及基础和应用研究，旨在更好地了解牙菌斑细菌的生物学，特别是与氧代谢和活性氧物种造成的损害有关的生物学。

DESCRIPTION (provided by applicant): The long-term objectives of the proposed research are to gain a more complete view of oxidative stress and oxidative damage to oral streptococci and to use this information to develop effective antimicrobial for control of Dental plaque pathogenicity, primarily related to Dental caries. The Specific Aims of the project are the following. Specific Aim 1 is focused on defining in more detail adaptive responses of S. mutans to oxidative stress. The definition will include determinations of factors that induce the responses, including acidification, but particularly aerobic growth and exposure to sulfhydryl agents. Determination of the details of these responses, especially their physiologic regulation, will depend on genetic tools we already have developed, including mutants in genes for protective enzymes and for regulatory proteins. Specific Aim 2 involves basic studies of respiration of oral streptococci, especially mutans streptococci, including strains isolated directly from Dental plaque, and use of mono-organism and mixed-organism biofilms. Another part of the Aim is to define in more detail the major cell targets for oxidative damage, especially proteins, and to assess the energetics of protective mechanisms against oxidative stress, most of which require ATP, NADH and/or NADPH to function. Specific Aim 3 is focused on translational research with investigation of small molecules, such as zinc cations, benzimidazoles or other sulfhydryl-reacting agents, such as allicin, chelators, fluoride and other halogens, transition metal cations and oxidative antimicrobials. The research will be closely interdigitated with the basic studies of the first 2 Specific Aims with a view to using of basic information in developing agents or combinations of agents potent for enhancing oxidative damage to oral bacteria. The translational work will include studies with mono-organism and mixed biofilms and determinations of cell/biofilm permeabilities to, and retentiveness of, the test antimicrobials to help us evaluate their potentials for prophylactic and therapeutic use in the mouth. The research is directly related to public health, primarily the control of Dental caries, which is the most prevalent infectious disease among young people in the American population and a growing problem for older Americans. The work involves basic and applied studies Aimed at a better understanding of the biology of Dental plaque bacteria related especially to oxygen metabolism and damage caused by reactive oxygen species.