Role of RNA polymerase in bacterial differentiation

RNA聚合酶在细菌分化中的作用

• 批准号: 8232295
• 负责人: Richard Marc Losick
• 金额: $ 63.71万
• 依托单位: HARVARD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1976
• 资助国家: 美国
• 起止时间: 1976-02-01 至 2016-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8232295
• 关键词: Address; Amino Acids; Amyloid fibers; Animal Model; Antibiotic Resistance; Bacillus anthracis; Bacillus subtilis; Back; Bacteria; Bioterrorism; Cells; Communities; Complex; Cytochrome a; DNA-Directed RNA Polymerase; Development; Devices; Electron Transport; Enterococcus; Environment; Event; Exhibits; Feedback; Frequencies; Funding Mechanisms; Gel; Gene Expression; Genes; Genus staphylococcus; Germination; Goals; Gram-Positive Bacteria; Growth; Human; Individual; Laboratory culture; Life; Life Cycle Stages; Lipoproteins; Measures; Mediating; Memory; Microbial Biofilms; Microfluidic Microchips; Molecular Biology; Organism; Peptidoglycan; Phosphotransferases; Plant Roots; Plants; Production; Progress Reports; Property; Pseudomonas; Public Health; Racemases; Relative (related person); Reproduction spores; Research; Role; Sigma Factor; Signal Transduction; Streptococcus; Structure; Surface; Swimming; System; Testing; Time; base; cell type; derepression; free behavior; insight; novel; pathogen; pathogenic bacteria; prevent; programs; research study; sensor histidine kinase; small molecule; success; time use

DESCRIPTION (provided by applicant): The objectives of the project are to uncover the mechanisms of gene control that turn on, and distinguish between, developmental programs of spore formation and matrix production by Bacillus subtilis. Spore formation has been traditionally viewed as a behavior of free-living cells, but we now understand that differentiation also occurs in the context of structured, multicellular communities (biofilms) consisting of chains of matrix-producing cells as well as spore-forming cells. Indeed, the mechanisms that govern entry into sporulation are intimately interwoven with those that govern matrix production. This proposal addresses important gaps in our understanding of sporulation and multicellularity with four specific aims: (1) We will identify the natural environmental signals that trigger spore formation and multicellularity by two sensor histidine kinases. (2) We will visualize cell fate switching between planktonic and matrix-producing states in real time using a newly devised microfluidic device. We will determine how a double-negative feedback loop controls switching and how cells discriminate between alternative fates of spore formation and matrix production. (3) We will determine how D-amino acids are produced late in the life cycle of the biofilm and how they trigger biofilm disassembly. We will determine the regulatory mechanisms that control the expression of the racemase genes that are responsible for D-amino acid production, how D-amino acids are incorporated into the peptidoglycan and how they trigger the release of an amyloid-fiber component of the matrix. (4) We will determine the full cascade of regulatory events that govern the differentiation of a cell into a spore, including the mechanisms that govern switching from one sigma factor to another. Understanding how D-amino acids cause biofilm disassembly will inform strategies for blocking biofilm formation by pathogenic bacteria. Also, research into gene control by B. subtilis, the principal model organism for Gram-positive bacteria, has provided, and will continue to provide, fundamental insights into the molecular biology of related, pathogenic bacteria, such as Staphylococcus, Enterococcus and B. anthracis. PUBLIC HEALTH RELEVANCE: An important problem in public health is the capacity of pathogenic bacteria to form surface- associated communities known as biofilms, which exhibit high levels of resistance to antibiotics. This research on the bacterium Bacillus subtilis is revealing novel and general approaches to preventing biofilm formation that appear to be applicable to a wide variety of pathogens, including Staphylococcus and Pseudomonas. Also, the research will provide insights into important human pathogens that are close relatives of B. subtilis, such as Staphylococcus, Streptococcus, and Enterococcus and the bioterrorism agent, Bacillus anthracis.

描述（由申请人提供）：该项目的目标是揭示启动并区分枯草芽孢杆菌孢子形成和基质产生的发育程序的基因控制机制。传统上，孢子形成被视为自由生活细胞的一种行为，但我们现在了解到，分化也发生在由基质产生细胞和孢子形成细胞链组成的结构化多细胞群落（生物膜）的背景下。事实上，控制进入孢子形成的机制与控制基质产生的机制密切相关。该提案解决了我们对孢子形成和多细胞性理解中的重要差距，有四个具体目标：（1）我们将通过两种传感器组氨酸激酶识别触发孢子形成和多细胞性的自然环境信号。 (2)我们将使用新设计的微流体装置实时可视化浮游状态和基质产生状态之间的细胞命运切换。我们将确定双负反馈回路如何控制切换以及细胞如何区分孢子形成和基质产生的不同命运。 (3) 我们将确定 D-氨基酸在生物膜生命周期后期如何产生以及它们如何引发生物膜分解。我们将确定控制负责 D-氨基酸生产的消旋酶基因表达的调节机制、D-氨基酸如何掺入肽聚糖以及它们如何触发基质的淀粉样蛋白纤维成分的释放。 (4) 我们将确定控制细胞分化为孢子的完整级联调控事件，包括控制从一种西格玛因子转换为另一种因子的机制。了解 D-氨基酸如何导致生物膜分解将为阻止病原菌形成生物膜提供策略。此外，对枯草芽孢杆菌（革兰氏阳性菌的主要模式生物）基因控制的研究已经并将继续为相关病原细菌（如葡萄球菌、肠球菌和芽孢杆菌）的分子生物学提供基础见解。炭疽病。 公共卫生相关性：公共卫生中的一个重要问题是病原菌形成表面相关群落（称为生物膜）的能力，这种群落对抗生素表现出高水平的耐药性。这项针对枯草芽孢杆菌的研究揭示了防止生物膜形成的新颖且通用的方法，这些方法似乎适用于包括葡萄球菌和假单胞菌在内的多种病原体。此外，该研究还将深入了解与枯草芽孢杆菌近亲的重要人类病原体，例如葡萄球菌、链球菌和肠球菌以及生物恐怖剂炭疽杆菌。