Environmental modulation of microbial conflict and cooperation

项目总结：微生物冲突与合作的环境调控 微生物对人类健康有巨大的影响，因为肠道往往是有益的 微生物群对病原菌的有害影响。这些健康结果的一个关键决定因素是 微生物群落内部以及群落与环境之间的相互作用 主持人。例子包括细菌群体集体灭活抗生素和交换 微生物种群中的营养物质。尽管这些互动显然很重要，但我们有能力 操纵它们来改善健康往往是最基本的。提高对……认识的主要障碍 微生物群落一直缺乏生态学理论模型和 实验上易驯化的微生物模型群落。我建议使用定量实验 微生物群落，探索环境变化如何改变 社区内的特殊互动。 在这笔赠款的过程中，我们将采取自下而上的方法来探索环境 变化将影响微生物群落内三种典型的相互作用形式。首先，我们会 探讨人口内部的简单合作，特别是这种合作是否可以限制 人口在不断恶化的环境中生存的能力。作为一个模型系统，我们将探索 萌芽酵母可以进化以在高盐浓度下生存，以及这种存活概率是如何决定的 取决于糖源是否需要人口内部的合作。接下来我们将研究营养素是如何 浓度调节互惠共生的性质，在这种共生中，两种微生物菌株交叉. 喂食必需的营养素。我们将证明，增加营养浓度可以改变 从互惠互利到寄生的互动，其中一个伙伴实际上受到另一个伙伴的伤害。 最后，我们将研究这样一种情况，在这种情况下，两个种群各自进行合作，但在某种程度上 这会伤害到其他人口。我们将证明，在低营养环境中，这些种群 可以共存，因为种群规模足够低，可以防止过度的负面互动，但作为 营养浓度增加，实际上可能会造成多样性的丧失。 我的目标是改变我们对微生物群落的理解，同时开发出具体的 可以用来对理论生态中的想法进行定量测试的模型社区。的领域 在过去的30年里，生态学和生物医学几乎没有什么思想交流，但我相信有很多 人类健康面临的关键挑战将需要生态方法。例如，许多概念 微生物群落生态学的发展可能对研究其他相互作用的研究人员有用 从免疫系统到癌症。

Project Summary: Environmental modulation of microbial conflict and cooperation Microorganisms have tremendous impacts on human health, from the often beneficial effects of the gut microbiome to the deleterious effects of pathogenic bacteria. A key determinant of these health outcomes is the interactions within the microbial community and between the community and the environment of the host. Examples include the collective inactivation of antibiotics by a bacterial population and exchange of nutrients within the microbial population. Despite the clear importance of these interactions, our ability to manipulate them to improve health is often rudimentary. A major obstacle to improved understanding of microbial communities has been the lack of feedback between theoretical models in ecology and experimentally tractable microbial model communities. I propose to use quantitative experiments of microbial communities to explore how environmental changes can transform the consequences of a particular interaction within the community. Over the course of this grant we will take a bottom-up approach to explore how environmental changes will influence three canonical forms of interactions within a microbial community. First we will explore simple cooperation within a population, and in particular whether this cooperation can limit the ability of the population to survive deteriorating environments. As a model system we will explore whether budding yeast can evolve to survive high salt concentrations, and how this survival probability depends upon whether the sugar source requires cooperation within the population. Next we will study how nutrient concentration modulates the properties of a mutualism in which two strains of micro-organism are cross- feeding essential nutrients. We will demonstrate that increasing nutrient concentrations can transform the interaction from a beneficial mutualism into a parasitism, where one partner is actually harmed by the other. Finally, we will study a situation in which two populations are each cooperating with themselves but in a way that harms the other population. We will demonstrate that in low nutrient environments these populations can coexist because population sizes are sufficiently low to prevent excessive negative interaction, but as nutrient concentrations increase there can actually be a loss of diversity. My goal is to transform our understanding of microbial communities while also developing concrete model communities that can be used to quantitatively test ideas from theoretical ecology. The fields of ecology and biomedicine have had little exchange of ideas over the last thirty years, but I believe that many key challenges to human health will require ecological approaches. For example, many of the concepts developed in microbial community ecology may be useful to researchers studying other interacting populations, from the immune system to cancer.