Cloning/Characterization of S. mutans Iron Stimulation

变形链球菌铁刺激的克隆/表征

基本信息

批准号：
7413618
负责人：
Grace A. Spatafora
金额：
$ 13.43万
依托单位：
MIDDLEBURY COLLEGE
依托单位国家：
美国
项目类别：
财政年份：
2004
资助国家：
美国
起止时间：
2004-07-15 至 2009-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7413618
关键词：
Acids Address Adolescence Affect Affinity Age American Animals Assimilations Bacteria Bacterial Genes Bacterial Infections Be++ element Beryllium Biological Assay Brevibacterium Cell Death Cell physiology Chemistry Chronic Cloning Communicable Diseases Communities Condition Corynebacterium diphtheriae Cultured Cells DNA-Binding Proteins Dental Plaque Dental Pulp Dental caries Development Diphtheria Toxin Disease Drug Delivery Systems Education Environment Family Fostering Future Gene Expression Gene Expression Regulation Genes Genus Mycobacterium Genus staphylococcus Goals Gram-Negative Bacteria Gram-Positive Bacteria Growth Homologous Gene Human Immunoglobulins Incidence Infection Invaded Ion Transport Ions Iron Iron Chelating Agents Iron-Binding Proteins Knowledge Laboratories Lead Left Link Literature Low income Membrane Membrane Proteins Metabolism Metals Microbe Microbial Biofilms Micronutrients Molecular Profiling Nutrient Oral cavity Organism Oxidative Stress Oxygen measurement, partial pressure, arterial Pathogenesis Pattern Pharmacologic Substance Phylogenetic Analysis Physiological Play Process Production Proliferating Proteins Public Health Reactive Oxygen Species Regulation Regulon Reporting Repression Research Proposals Role Services Siderophores Staphylococcus aureus Staphylococcus epidermidis Streptococcus mutans Sugar Substitute Surface Suspension substance Suspensions System Time Tissues Tooth structure Toxin Transcription Repressor/Corepressor United States United States Centers for Medicare and Medicaid Services Vaccines Virulence Virulence Factors Water fluoridation Work base biological adaptation to stress deprivation extracellular in vivo microbial microorganism microorganism growth oral streptococci pathogen pathogenic bacteria response tooth surface transcription factor uptake

项目摘要

DESCRIPTION (provided by applicant): Iron is an essential micronutrient for bacterial pathogens and their mammalian hosts, and hence competition for this element is an integral component of the infectious process. Extracellular ferrous iron is biologically unavailable to invading pathogens because it is largely sequestered to host proteins, and in its free form rapidly oxidizes to the insoluble ferric state. Bacteria often respond to the iron withholding system of the host by turning on iron scavenging systems and virulence determinants to promote bacterial survival and dissemination. Among the most extensively studied metal ion-dependent regulators in Gram-positive bacteria is DtxR, a DNA-binding protein, in Corynebacterium diphtheriae, and its phylogenetic homologs SirR in Staphylococcus epidermidis and MntR in Staphylococcus aureus. Importantly, these metalloregulators function as transcription factors that modulate the expression of bacterial virulence genes and high affinity metal ion uptake systems related to virulence and oxidative stress. Work conducted in our laboratory on Streptococcus mutans, the principal acidogenic component of human dental plaque, revealed a DtxR homolog that regulates a repertoire of genes, and accumulating evidence is consistent with a role for iron in S. mutans biofilm formation, the oxidative stress response, and acid tolerance. Indeed, the identification and characterization of genes involved in these and other pathogenic processes is a high priority since they can prove to be future drug targets. The major goal of this research proposal will focus on elucidating iron-dependent gene regulation and its role in S. mutans-induced cariogenesis. The specific aims include 1) characterizing iron-responsive genes that belong to a putative S. mutans Dlg regulon; 2) cloning and characterizing other iron-dependent genes in S.mutans that are not subject to Dlg control; 3) examining the expression of S. mutans Dlg- and iron-responsive genes in environments that approximate the human oral cavity; and 4) establishing a correlation between Dlg/iron-regulated gene expression and S. mutans-induced cariogenesis.

描述（由申请人提供）：铁是细菌病原体及其哺乳动物宿主的必需微量营养素，因此对该元素的竞争是感染过程中不可或缺的组成部分。细胞外二价铁在生物学上对于入侵病原体来说是不可利用的，因为它很大程度上被宿主蛋白质隔离，并且其游离形式迅速氧化成不溶性三价铁状态。细菌通常通过开启铁清除系统和毒力决定因素来响应宿主的铁保留系统，以促进细菌的存活和传播。革兰氏阳性菌中研究最广泛的金属离子依赖性调节因子是白喉棒杆菌中的 DtxR（一种 DNA 结合蛋白），以及表皮葡萄球菌中的系统发育同源物 SirR 和金黄色葡萄球菌中的 MntR。重要的是，这些金属调节剂充当转录因子，调节细菌毒力基因的表达以及与毒力和氧化应激相关的高亲和力金属离子摄取系统。我们实验室对变形链球菌（人类牙菌斑的主要产酸成分）进行的研究揭示了一种可调节基因库的 DtxR 同源物，并且积累的证据与铁在变形链球菌生物膜形成（氧化应激反应）中的作用一致。和耐酸能力。事实上，参与这些和其他致病过程的基因的识别和表征是当务之急，因为它们可以被证明是未来的药物靶标。该研究计划的主要目标将集中于阐明铁依赖性基因调控及其在变形链球菌诱导的龋齿发生中的作用。具体目标包括 1) 表征属于假定的变形链球菌 Dlg 调节子的铁反应基因； 2)克隆和表征变形链球菌中不受Dlg控制的其他铁依赖性基因； 3) 在接近人类口腔的环境中检查变形链球菌 Dlg 和铁反应基因的表达； 4)建立Dlg/铁调节基因表达与变形链球菌诱导的龋齿发生之间的相关性。