Intra- and interspecific siderophore cheating in bacteria

细菌种内和种间铁载体作弊

• 批准号: 1616967
• 负责人: Martin Schuster
• 金额: $ 56.92万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-01 至 2021-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1616967&HistoricalAwards=false
• 关键词: Intra; interspecific; siderophore; cheating; bacteria

The goal of this project is to study mechanisms that help maintain cooperative iron acquisition in bacterial communities. Cooperative iron acquisition is crucial to the survival of many microbial communities, but it is vulnerable to exploitation by social cheaters that reap the benefits of iron acquisition without paying the cost. Cooperative iron acquisition is widespread in microbial communities, including communities that are important for soil ecology, agriculture, and medicine. This work will provide important information about the conditions and circumstances that stabilize such communities and general information about how more complex communities are stabilized. This project will contribute to the training and career development of students at the graduate, undergraduate and high school levels.Much has been learned about the molecular mechanisms of microbial cooperative behaviors such as biofilm formation, virulence, and nutrient acquisition. However, only recently have microbiologists also begun to investigate these behaviors from the perspective of social evolution. The focus of this project is on the evolutionary stability of cooperative iron acquisition in pseudomonads. Several Pseudomonas species acquire iron by secreting pyoverdines, a structurally diverse class of non-ribosomal peptide siderophores that are internalized by cognate receptors. The evolutionary stability of pyoverdine cooperation is challenged by intraspecific cheating between P. aeruginosa pyoverdine producers and non-producers, and by interspecific cheating between two Pseudomonas species, P. aeruginosa and P. protegens, in which the latter recognizes the pyoverdine produced by the former but not vice versa. Both cases involve the potential exploitation of cooperative pyoverdine production by cells that reap the benefits without paying the costs. Based on preliminary experimental and modeling data, it is hypothesized that bacterial growth physiology, specifically the nature of the growth-rate limiting nutrient, and asymmetric competition, specifically pyoverdine receptor affinity, are two important factors that determine the costs and benefits of cheating. These hypotheses will be tested with a combination of modeling and experimental work. Modeling will involve whole-genome metabolic models and dynamic population growth models. Experimental work will involve batch and chemostat growth of single and co-cultures under defined nutrient conditions, as well as measurements of pyoverdine receptor binding affinities and expression levels. These studies will provide insights into the mechanisms that contribute to the evolutionary stability of cooperative iron acquisition. Cooperative iron acquisition and other microbial social behaviors are of great relevance to natural ecosystems and have implications for the evolution of sociality in general. Graduate, Undergraduate and high school students will be trained in a wide range of skills in microbial genetics, physiology, biochemistry, evolutionary biology, and mathematical modeling. High school students will be hosted through the Apprenticeship for Science and Engineering, a summer internship program at Oregon State University.

该项目的目的是研究有助于维持细菌群落中合作铁的机制。合作铁的获取对于许多微生物群落的生存至关重要，但是它很容易受到社会作弊者的剥削，从而在不支付成本的情况下获得了铁的好处。合作铁的采集在微生物社区中广泛存在，包括对土壤生态学，农业和医学重要的社区。这项工作将提供有关稳定此类社区的条件和环境的重要信息，以及有关更复杂社区如何稳定的一般信息。该项目将有助于研究生，本科和高中级的学生的培训和职业发展。但是，直到最近，微生物学家也开始从社会进化的角度研究这些行为。该项目的重点在于假单胞菌中合作铁的进化稳定性。几种假单胞菌物种通过分泌Pyoverdines来获取铁，这是一种结构上多样化的非核糖体肽铁载体，被同源受体内化。 Pyoverdine合作的进化稳定性受到铜绿假单胞菌Pyoverdine生产商和非生产者之间的种内作弊的挑战，以及两个假单胞菌（P. eruginosa p. eruginosa and P. p. prodegens）之间的种间作弊，而后者则识别以前但不是Vice Vice Versa所产生的2015年的pyoverdine。这两种情况都涉及通过在不支付费用的情况下获得收益的细胞对合作式Pyoverdine生产的潜在剥削。基于初步实验和建模数据，假设细菌生长生理学，特别是生长速率限制营养素的性质，以及不对称的竞争，特别是Pyoverdine受体亲和力，是确定作弊成本和收益的两个重要因素。这些假设将通过建模和实验工作的结合进行测试。建模将涉及全基因组代谢模型和动态种群增长模型。实验性工作将涉及在定义的养分条件下单个和共培养的批处理和化学仪表生长，以及对Pyoverdine受体结合亲和力和表达水平的测量。这些研究将提供有关有助于合作铁的进化稳定性的机制的见解。合作铁的获取和其他微生物社会行为与自然生态系统具有很大的相关性，并且对一般的社会发展具有影响。毕业生，本科和高中生将接受各种技能，以了解微生物遗传学，生理学，生物化学，进化生物学和数学建模。高中生将通过俄勒冈州立大学的暑期实习计划的科学与工程学徒制托管。