Molecular mechanisms of adaptive diversity in Burkholderia biofilms

伯克霍尔德杆菌生物膜适应性多样性的分子机制

基本信息

批准号：
9258441
负责人：
Vaughn Cooper
金额：
$ 26.86万
依托单位：
UNIVERSITY OF PITTSBURGH AT PITTSBURGH
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-01-01 至 2019-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9258441
关键词：
Adhesions Adverse effects Affect Archives Bacteria Binding Biochemistry Biology Biophysics Burkholderia Chronic Communities Complex Cystic Fibrosis Development Diffuse Environment Evolution Foundations Generations Genetic Goals Growth Guanosine Monophosphate Hereditary Disease In Vitro Infection Learning Life Life Style Mass Spectrum Analysis Metabolism Methods Microbial Biofilms Modeling Molecular Molecular Genetics Mutate Mutation Periodicity Persons Phenotype Physiological Physiology Population Population Genetics Predisposition Process Production Productivity Proteins Pseudomonas aeruginosa Regulation Resistance Second Messenger Systems Signal Transduction Structure Surface System Tertiary Protein Structure Testing Time Treatment Cost Variant antimicrobial bacterial resistance burden of illness cost diguanylate cyclase experimental study fitness in vitro Model in vivo mortality multidisciplinary mutant novel pathogen phosphoric diester hydrolase public health relevance reconstruction screening structural biology trait transcriptome sequencing

项目摘要

DESCRIPTION (provided by applicant): Biofilms are associated with hundreds of thousands of infections each year and greatly increase treatment costs and mortality. These adverse effects are caused not only by increased resistance of bacteria living in the biofilm matrix but likely also by adaptive evolution of mutants into different, recalcitrant forms. To study this evolutionary process in biofilms we devised a method enabling long-term selection of populations of the opportunistic pathogen Burkholderia cenocepacia that undergo a cycle of attachment, biofilm assembly, and dispersal. Selection repeatedly favored mutations in loci commonly mutated during chronic infections, suggesting that biofilm adaptation recapitulates aspects of evolution during infections. This proposal focuses on two genetic loci that coordinate the sensing of a secreted signal (BDSF) with internal regulation of a switch governing biofilm production (cyclic-di-GMP). Mutations in different protein domains led to different ecological strategies and together different mutants produced a more robust biofilm. The overarching goal of this project is to precisely define the selective advantages of mutants with different strategie of signaling, adhesion, and dispersal in diverse biofilm environments. To tackle this complex problem we have assembled a multidisciplinary team with expertise in molecular genetics and evolutionary biology, biochemistry and mass spectrometry, and biophysical structure-function analysis. Our objectives are to 1) quantify how mutants that vary in sensing BDSF and producing cyclic-di-GMP are adaptive in biofilm communities, 2) determine how BDSF mechanistically controls the activity of the primary locus under selection, and the effects of adaptive mutations on this process, and 3) to develop an ecological model of how these processes operate in mixed-mutant and mixed-species communities. We expect to learn how this system may be manipulated to induce dispersal from biofilms and increase their susceptibility, which could be broadly relevant for developing novel antimicrobials.

描述（由申请人提供）：生物膜每年与数十万例感染相关，并大大增加治疗成本和死亡率。这些不利影响不仅是由生活在生物膜基质中的细菌抵抗力增加引起的，而且可能是由突变体适应性进化成不同的顽固形式引起的。为了研究生物膜中的这种进化过程，我们设计了一种方法，能够长期选择经历附着、生物膜组装和扩散循环的机会性病原体新洋葱伯克霍尔德菌种群。选择反复有利于慢性感染期间常见突变的基因座的突变，这表明生物膜适应概括了感染期间进化的各个方面。该提案重点关注两个基因位点，它们协调分泌信号（BDSF）的传感与控制生物膜产生的开关（环二-GMP）的内部调节。不同蛋白质结构域的突变导致不同的生态策略，不同的突变体共同产生了更强大的生物膜。该项目的总体目标是精确定义在不同生物膜环境中具有不同信号、粘附和分散策略的突变体的选择优势。为了解决这个复杂的问题，我们组建了一个多学科团队，拥有分子遗传学和进化生物学、生物化学和质谱以及生物物理结构功能分析方面的专业知识。我们的目标是 1) 量化在感知 BDSF 和产生环二 GMP 方面不同的突变体如何在生物膜群落中适应，2) 确定 BDSF 如何机械地控制选择下的主要基因座的活性，以及适应性突变对生物膜群落的影响。这个过程，以及3）开发一个生态模型来解释这些过程如何在混合突变体和混合物种群落中运作。我们希望了解如何操纵该系统来诱导生物膜分散并增加其敏感性，这可能与开发新型抗菌药物广泛相关。