COBRE: UID: PROJ 1: EVOLUTION OF ANTIBIOTIC RESISTANCE PLASMID HOST RANGE

COBRE：UID：项目 1：抗生素抗性质粒宿主范围的进化

• 批准号: 8359572
• 负责人: Eva M. Top
• 金额: $ 18.61万
• 依托单位: UNIVERSITY OF IDAHO
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-02-01 至 2012-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8359572
• 关键词: Address; Affect; Antibiotic Resistance; Bacteria; Centers of Research Excellence; Communicable Diseases; DNA Sequence; Drug resistance; Effectiveness; Evolution; Funding; Genes; Goals; Grant; Human; Multi-Drug Resistance; National Center for Research Resources; Parasites; Pharmacotherapy; Plasmids; Principal Investigator; Process; Proteins; Public Health; Replication Initiation; Replicon; Research; Research Infrastructure; Resistance; Resources; Source; Testing; Time; United States National Institutes of Health; Work; cost; fight against; helicase; improved; mathematical model; mutant; pathogen

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Conjugative transfer of antibiotic resistance genes by plasmids has greatly contributed to the rapid spread of drug resistance among bacterial pathogens, thereby decreasing the effectiveness of various treatment options for infectious diseases in humans. While some plasmids only transfer and stably replicate in a narrow range of hosts (NHR), so-called broad-host-range (BHR) plasmids transfer and replicate in distantly related bacteria, thereby shuffling resistance genes across taxonomic barriers. Our long-term goal is to limit the rapid spread of multi-drug resistance to important human pathogens, but first a fundamental understanding of the evolution of plasmid host range is essential. Our overall hypothesis is that the host range of plasmids can evolve, much like that of parasites, to become wider or narrower over evolutionary time. To test this hypothesis, we propose the following specific aims: 1) To elucidate evolutionary changes that permit a narrow-host-range plasmid to expand or shift its host range, and 2) To elucidate evolutionary changes that cause host range contraction of a broad-host-range plasmid as a result of long-term association with a single host. To address the first aim, we will evolve the NHR mini-replicon mini-F in four bacterial hosts that show different initial levels of plasmid stability. The DNA sequences of the evolved plasmids will be determined to identify genotypic changes that cause a host range shift or expansion. We postulate that plasmid adaptation resulting in improved stability in one poor host will also improve the stability in other hosts. Under Specific Aim 2, we will examine evolved mutants of the BHR mini-replicon mini-pBP136 that were recently shown to have undergone a shift in host-range. We postulate that the observed shift is due to changes in the interaction of the replication initiation protein TrfA1 with the host helicase. For both Aims mathematical models and statistical analyses will be developed and used to identify the parameters that affect these evolutionary processes. Relevance to public health: This work will unravel the mechanisms of plasmid-host interactions that determine the host range of multi-drug resistance plasmids. This may reveal attractive targets for specific drug therapy in the fight against the alarming spread of drug resistance in human pathogens.

该子项目是利用资源的众多研究子项目之一 由 NIH/NCRR 资助的中心拨款提供。子项目的主要支持 并且子项目的首席研究员可能是由其他来源提供的， 包括其他 NIH 来源。 子项目可能列出的总成本 代表子项目使用的中心基础设施的估计数量， NCRR 赠款不直接向子项目或子项目工作人员提供资金。 通过质粒接合转移抗生素抗性基因极大地促进了细菌病原体中耐药性的快速传播，从而降低了人类传染病的各种治疗方案的有效性。虽然一些质粒仅在窄范围宿主（NHR）中转移和稳定复制，但所谓的宽宿主范围（BHR）质粒在远缘相关细菌中转移和复制，从而跨越分类学障碍改变抗性基因。我们的长期目标是限制对重要人类病原体的多重耐药性的快速传播，但首先对质粒宿主范围的进化有一个基本的了解是至关重要的。我们的总体假设是，质粒的宿主范围可以进化，就像寄生虫一样，随着进化的时间变得更宽或更窄。为了检验这一假设，我们提出以下具体目标：1）阐明允许窄宿主范围质粒扩大或改变其宿主范围的进化变化，2）阐明导致宽宿主范围收缩的进化变化。 -由于与单一宿主长期结合而产生的宿主范围质粒。为了实现第一个目标，我们将在四种细菌宿主中进化 NHR 迷你复制子 mini-F，这些细菌宿主表现出不同的初始质粒稳定性水平。进化质粒的 DNA 序列将被确定，以识别导致宿主范围转移或扩展的基因型变化。我们假设质粒适应导致一种不良宿主的稳定性提高，也将提高其他宿主的稳定性。在具体目标 2 下，我们将检查 BHR 迷你复制子 mini-pBP136 的进化突变体，最近显示该突变体经历了宿主范围的转变。我们假设观察到的转变是由于复制起始蛋白 TrfA1 与宿主解旋酶相互作用的变化所致。对于这两个目标，将开发数学模型和统计分析，并用于识别影响这些进化过程的参数。与公共卫生的相关性：这项工作将揭示质粒与宿主相互作用的机制，该相互作用决定了多药耐药质粒的宿主范围。这可能会揭示特定药物治疗的有吸引力的目标，以对抗人类病原体中令人震惊的耐药性蔓延。