Mechanisms of cellular respiration-dependent cell lysis and its impact on biofilm formation and disassembly in Staphylococcus aureus.

本提案的目的是确定a)调节生物膜形成的因素和机制。 和扩散作为细胞呼吸的函数在金黄色葡萄球菌中，b)决定如何表达 这些因素中的一种是受调节的，以及c)确定调节系统对 细胞呼吸状态的改变。金黄色葡萄球菌是人类的共生菌和主要的 医院和社区获得性感染的原因。金黄色葡萄球菌要想定植并入侵宿主组织，它必须 成功感知和应对环境扰动以及个人主义和 多细胞行为。金黄色葡萄球菌有能力形成称为生物膜的多细胞群落，这是 反复葡萄球菌感染的病原学因素。我们发现金黄色葡萄球菌对生物膜有调节作用 通过呼吸途径形成的电子流量的函数。我们发现，当金黄色葡萄球菌 没有末端电子受体的生长(发酵生长)细胞裂解增加，这是 导致包括DNA在内的细胞内成分的释放。释放的dna对生物膜至关重要。 有助于将生物膜基质中的细胞结合在一起的完整性。我们还发现，添加了 发酵生物膜的末端电子受体导致生物膜的分散。我们已经确定了两个全球 调节发酵生物膜形成的调控系统。这两个监管系统都是 被证明是发病所必需的，但它们的分子刺激目前尚不清楚。最重要的是 这个项目的目标是了解金黄色葡萄球菌内发生的生理变化 细胞呼吸，并研究这些变化如何影响群落结构。我们将使用基因， 生理学、生化和分子技术，以研究一种未被充分研究的导致S。 金黄色葡萄球菌调节细胞裂解，从而影响生物膜的形成和扩散。我们将进一步定义 影响发酵细胞裂解和生物膜形成的因素。我们还将定义因素和 发酵生物膜扩散的分子机制。我们将研究分子刺激 并研究另一个监管系统(SRR)如何控制 改变细胞裂解和生物膜形成的因素。最终，我们希望应用我们的发现来调节 金黄色葡萄球菌使用改变细胞信号的分子的行为，从而积极影响感染 结果。研究的完成将有助于提供有关葡萄球菌的两个要求的知识 发病机制：环境感知和生物被膜形成。

The objectives of this proposal are to determine a) the factors and mechanisms that modulate biofilm formation and dispersal as a function of cellular respiration in Staphylococcus aureus, b) determine how the expression of these factors is regulated, and c) determine the molecular stimuli for a regulatory system that responds to alterations in the cellular respiratory status. Staphylococcus aureus is a human commensal and a leading cause of hospital and community acquired infections. For S. aureus to colonize and invade host tissues, it must successfully sense and respond to environmental perturbations and transition between individualistic and multicellular behaviors. S. aureus has the ability to form multicellular communities called biofilms, which are the etiologic agents of recurrent staphylococcal infections. We have found that S. aureus modulates biofilm formation as a function of electron flux though respiratory pathways. We have found that when S. aureus is growing without a terminal electron acceptor (fermentative growth) there is an increase in cell lysis, which leads to the release of intracellular components including DNA. The DNA that is released is vital to biofilm integrity where it aids in holding the cells together in the biofilm matrix. We also discovered that the addition of a terminal electron acceptor to fermentative biofilms resulted in biofilm dispersal. We have identified two global regulatory systems that mediate fermentative biofilm formation. Both of these regulatory systems have been shown to be necessary for pathogenesis, but their molecular stimuli are currently unknown. The overarching goal of this project is to understand the physiological changes that occur within S. aureus upon changes in cellular respiration, and examine how these changes affect the community structure. We will use genetic, physiologic, biochemical, and molecular techniques to investigate an understudied variable that causes S. aureus to modulate cell lysis, and thereby affect biofilm formation and biofilm dispersal. We will further define the factors involved in fermentative cell lysis and biofilm formation. We will also define the factors and molecular mechanisms involved in the dispersal of fermentative biofilms. We will examine the molecular stimuli of one regulatory system (Sae) and examine how another regulatory system (Srr) controls the expression of factors that alter cell lysis and biofilm formation. Ultimately, we would like to apply our findings to modulate the behavior of S. aureus using molecules that alter cell signaling, and thereby, positively affect infection outcomes. Completion of the studies will help provide knowledge about two requirements for staphylococcal pathogenesis: environmental sensing and biofilm formation.