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Biological mechanisms and consequences of efficient extracellular electron transfer in Pseudomonas aeruginosa

铜绿假单胞菌有效细胞外电子转移的生物学机制和后果

基本信息

批准号：
10660729
负责人：
Dianne K Newman
金额：
$ 74.75万
依托单位：
CALIFORNIA INSTITUTE OF TECHNOLOGY
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-05-08 至 2028-06-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10660729
关键词：
Affect Aminoglycosides Animals Antibiotic Therapy Antibiotics Bacteria Bioenergetics Biological Burn injury Cells Charge Clinic Clinical Colistin Consumption Cystic Fibrosis Cystic Fibrosis sputum Cytolysis DNA Defense Mechanisms Development Diffusion Electron Transport Electrons Equilibrium Excision Eye Infections Fluoroquinolones Foundations Homeostasis Infection Knowledge Lead Link Lung Measures Mediating Metabolic Methods Microbial Biofilms Modeling Nutrient Oxidants Oxidation-Reduction Oxygen Patients Pharmaceutical Preparations Physiological Pigments Polymers Predisposition Property Pseudomonas Pseudomonas Infections Pseudomonas aeruginosa Pseudomonas aeruginosa infection Pyocyanine Reaction Role Signal Transduction Signaling Molecule Specific qualifier value System Techniques Technology Testing Virulence Factors Work acute infection antibiotic tolerance beta-Lactams burn wound cell type chronic infection clinically relevant design diabetic ulcer effective therapy experimental study extracellular fitness foot improved in vivo insight opportunistic pathogen response skin wound tool treatment strategy ventilator-associated pneumonia wound

项目摘要

PROJECT SUMMARY Pseudomonas aeruginosa is an opportunistic pathogen found in acute infections (burns, wounds, ventilator associated pneumonia, eye infections) and chronic infections of the foot (diabetic ulcers) and lung (cystic fibrosis). This bacterium commonly survives in these contexts as a biofilm, the formation and high-level antibiotic tolerance of which interferes with effective patient treatment. A defining aspect of P. aeruginosa is its ability to make pyocyanin, a colorful redox-active pigment that contributes to biofilm development and its fitness in the context of infection. Pyocyanin has been detected at appreciable concentrations in skin wounds and in cystic fibrosis sputum, and pyocyanin has been shown to be a virulence factor in animal infection models. Pyocyanin exerts a range of effects over the cells that produce it, ranging from toxic in the presence of oxygen to beneficial in its absence; under oxygen-limited conditions, pyocyanin serves as an electron acceptor that promotes redox-balancing and long-term survival. These toxic and beneficial roles are important at different times in biofilm development, with early pyocyanin -promoted lysis generating extracellular DNA (eDNA), a key component of the biofilm matrix together with exopolysaccharides. Recently, we determined that eDNA underpins pyocyanin’s ability to promote extracellular electron transfer (EET) within biofilms, facilitating metabolic activity in the oxygen-limited interior. We found that eDNA enables both the retention of pyocyanin and charge transfer to pyocyanin. Critical to making these discoveries was our development of new bioelectrochemical technologies and approaches and the application of advanced spectroscopic techniques to directly probe EET in biofilms. We now seek to extend our interdisciplinary work to gain a mechanistic understanding of how biofilm EET efficiency is tuned by the composition of the matrix and the consequences this may have for antibiotic tolerance. Does the ratio of certain exopolysaccharides (Pel, Psl) to eDNA modulate pyocyanin diffusivity in the matrix, controlling EET efficiency? Does EET efficiency correlate with the rate of redox balancing in the biofilm interior? How do pyocyanin-mediated cellular effects, including EET, contribute to antibiotic tolerance in biofilms, and do these mechanisms differ according to the amount of oxygen in the microenvironment? Does the relative sensitivity of diverse pyocyanin-producing P. aeruginosa isolates to antibiotics correlate with their matrix composition and EET efficiency? Aim1 will explore how the matrix composition, particularly the ratio of Pel and Psl exopolysaccharides to eDNA, determines EET efficiency. Aim 2 will test the hypothesis that pyocyanin is a versatile intrinsic tolerance factor, where PYO-EET helps P. aeruginosa biofilms tolerate mechanistically distinct and clinically important antibiotic classes via bioenergetic effects and/or by inducing defense mechanisms; we predict the dominant mechanism by which PYO impacts tolerance will differ as a function of oxygen concentration. Attainment of these objectives will lay the foundation of basic knowledge necessary to design better strategies to control P. aeruginosa biofilms.

项目摘要铜绿假单胞菌是一种机会致病菌，在急性感染（烧伤，创伤，呼吸机相关性肺炎、眼部感染）以及足部（糖尿病溃疡）和肺部（囊性纤维化）。这种细菌通常以生物膜的形式在这些环境中生存，其形成和高水平的其抗生素耐受性干扰有效的患者治疗。铜绿假单胞菌的一个定义方面是其绿脓菌素是一种彩色的氧化还原活性色素，有助于生物膜的发育，在感染的背景下，绿脓菌素已被检测到在皮肤伤口的可观浓度和囊性纤维化痰中，绿脓菌素已被证明是动物感染中的毒力因子模型绿脓菌素对产生它的细胞有一系列的影响，从在存在的情况下有毒，氧在它的缺席是有益的;在氧限制的条件下，绿脓菌素作为电子受体促进氧化还原平衡和长期生存。这些有毒和有益的作用是重要的，在生物膜发育的不同时期，早期绿脓菌素促进裂解产生胞外DNA DNA是生物膜基质的关键组分，与胞外多糖一起。最近，我们确定， eDNA支持绿脓菌素促进生物膜内细胞外电子转移（EET）的能力，在氧气有限的内部进行代谢活动。我们发现eDNA既能保留绿脓菌素，并将电荷转移到绿脓菌素。做出这些发现的关键是我们开发了新的生物电化学技术和方法以及先进的光谱技术在直接探测生物膜中的EET。我们现在寻求扩展我们的跨学科工作，以获得一个机械的了解生物膜EET效率如何通过基质的组成和结果来调节这可能导致了抗生素耐药性。某些胞外多糖（Pel，Psl）与eDNA的比例调节绿脓菌素在基质中的扩散，控制EET效率？EET效率是否与在生物膜内部的氧化还原平衡率？绿脓菌素介导的细胞效应，包括EET，有助于生物膜中的抗生素耐受性，并且这些机制是否根据抗生素的量而不同？微环境中的氧气不同绿脓杆菌的相对敏感性是否分离株对抗生素的敏感性与其基质组成和EET效率相关吗？AIM 1将探索如何基质组成，特别是Pel和Psl胞外多糖与eDNA的比例，决定了EET 效率目的2将检验绿脓菌素是一种多功能的内在耐受因子的假设，其中PYO-EET 帮助铜绿假单胞菌生物膜耐受机械上不同的和临床上重要的抗生素类，生物能量效应和/或诱导防御机制;我们预测的主导机制， PYO影响耐受性将作为氧浓度的函数而不同。这些目标的实现，为设计更好的控制铜绿假单胞菌生物膜的策略奠定基础。