Interactions between envelope stress responses, bacteriophages and the environment

像动物和植物一样，细菌也容易受到病毒感染。细菌病毒被称为噬菌体，它们被认为生活在地球上所有环境中，其浓度比它们感染的细菌高得多。其中一个原因是，一种被称为温带噬菌体的细菌病毒可以感染细菌并整合到它们的染色体中，在那里它们可以安静地生活很多代，然后再次活跃起来。大多数细菌被认为在它们的基因组中含有温和的噬菌体。温和的噬菌体从细菌染色体上解放出来，导致许多新病毒的产生，并感染和杀死邻近的敏感微生物，从而为携带此类病毒的细菌群体提供了竞争优势。这一点很重要，因为大多数细菌与许多其他微生物生活在表面相关的群落中，在那里它们争夺空间和资源，并暴露在威胁其生计的环境压力源中。对于动物大肠中的一种居民--大肠杆菌来说，情况就是如此。在进入肠道的途中和肠道内，大肠杆菌必须经受住许多潜在的致命条件，包括我们身体产生的有毒抗菌物质和常驻共生微生物产生的噬菌体。为了生存，大肠杆菌使用多个包膜应激反应来检测和响应这些潜在的致命物质。我假设细菌包膜应激反应对噬菌体很敏感，它们改变微生物细胞的方式影响噬菌体感染的过程和/或生存压力的能力。我进一步预测，噬菌体与大肠杆菌的包膜及其遗传网络相互作用并改变，从而影响压力适应功能。我的实验室在最近从一只小鼠的消化道分离出的一株“野生”大肠杆菌中发现了一种名为Kapi1的新的温带噬菌体，并对其进行了鉴定。我们将利用我们在细菌遗传学和包膜应激反应研究方面的专业知识，启动一项新的研究计划，以调查噬菌体和细菌如何相互作用，影响微生物的适应性和应激适应。我们的工作将为未来控制和利用环境中的细菌、用于工业用途以及改善人类和动物健康的努力提供信息。

Like animals and plants, bacteria are subject to viral infections. Bacterial viruses are called bacteriophages and they are thought to inhabit all environments on Earth in concentrations much higher than those of the bacteria they infect. One reason for this is that a type of bacterial viruses called temperate bacteriophages can infect bacteria and integrate into their chromosomes, where they can live quiescently for many generations before becoming active again. Most bacteria are thought to contain temperate bacteriophages in their genomes. The liberation of temperate bacteriophages from the bacterial chromosome results in the production of many new viruses and the infection and killing of neighbouring susceptible microbes, thus providing a competitive advantage to bacterial populations harbouring such viruses. This is important, since most bacteria live in surface-associated communities with many other microbes where they compete for space and resources and are exposed to environmental stressors that threaten their livelihoods. This is true for Escherichia coli, an inhabitant of the large intestine of animals. En route to, and within the intestine, E. coli must withstand many potentially lethal conditions, including toxic antimicrobial substances produced by our bodies and bacteriophages produced by resident commensal microbes. In order to survive, E. coli uses multiple envelope stress responses to detect and respond to these potentially lethal substances. I hypothesize that bacterial envelope stress responses are sensitive to bacteriophage and that they alter the microbial cell in ways that impact the course of bacteriophage infection and/or the ability to survive stress. I further predict that bacteriophages interact with and alter the E. coli envelope and its genetic network to impact stress adaptive functions. My lab discovered and characterized a new temperate bacteriophage called Kapi1 in a recently isolated "wild" strain of E. coli from a mouse digestive tract. We will use our expertise in bacterial genetics and the study of envelope stress responses to initiate a new research program to investigate how bacteriophages and bacteria interact with each other to influence microbial fitness and stress adaptation. Our work will inform future efforts to control and harness bacteria in the environment, for industrial use, and to improve human and animal health.