Phage resistance and mobile genetic elements in Vibrio cholerae

霍乱弧菌等水传播病原体对全球健康构成重大威胁。霍乱弧菌可持续存在 水环境，它可能在流行地区和#年造成毁灭性的霍乱暴发。 基础设施受损、人口流离失所的脆弱地区。东道主- 决定疾病结果和霍乱传播动态的病原体相互作用发生在 包括捕食性细菌病毒(噬菌体)的复杂微生物生态系统。关于分子的知识 噬菌体捕食对流行菌株选择的影响是必要的，以加强我们的 了解影响霍乱弧菌进化和流行病学的因素。我们发现有一本小说 一组称为PLE(噬菌体可诱导的染色体岛状元件)的可移动遗传元件是关键 霍乱弧菌用来防御噬菌体攻击的武器。我们的假设是PLE是 有效的、高度特异的抗病毒屏障，通过两种不同的机制确保噬菌体不会 繁殖并传播到邻近的霍乱弧菌细胞。我们的数据表明，PLE通过抑制 通过在所有子代噬菌体之前破坏受感染的细菌细胞来产生必需的噬菌体蛋白 完成它们的复制周期。为了理解PLE活动的机械性细节，我们将追求以下几点 具体目标：1)我们将定义允许快速刺激PLE活动的调控网络。 霍乱弧菌受到噬菌体的攻击，并确定如何赋予PLE与噬菌体相互作用的特异性。2) 我们将确定PLE如何干扰噬菌体产生必需蛋白质的能力。在这一目标下，我们 将结合使用功能基因组方法和突变分析来分离这一方面的 PLE介导的细胞裂解的PLE活性。3)我们将确定PLE介导的细菌的分子基础 细胞裂解。我们将表征对细胞毒性PLE编码产物不敏感的抑制物 了解PLE如何有效地杀死感染霍乱弧菌的噬菌体。拟议的研究将确定如何 噬菌体捕食形成流行霍乱弧菌的基因组。这一知识将增进我们的理解 在健康和患病状态下，噬菌体对微生物种群的干扰，以及进一步提高我们的能力 为了治疗或预防的利益而操纵这些社区。

Waterborne pathogens like Vibrio cholerae pose significant threats to global health. V. cholerae can persist in the aquatic environment, and it can emerge to cause devastating cholera outbreaks in endemic regions and in vulnerable areas where infrastructure has been compromised and populations have been displaced. The host- pathogen interactions that dictate disease outcome and cholera transmission dynamics occur in the context of a complex microbial ecosystem that includes predatory bacterial viruses (phages). Knowledge of the molecular consequences of phage predation on the selection of epidemic strains is needed to enhance our understanding of the forces impacting the evolution and epidemiology of V. cholerae. We found that a novel group of mobile genetic elements called PLEs (phage-inducible chromosomal island-like elements) are a key weapon that epidemic V. cholerae uses to protect against phage attack. Our hypothesis is that PLEs are potent, highly specific, antiviral barriers that act through two distinct mechanisms to ensure that phage do not propagate and spread to neighboring V. cholerae cells. Our data indicate that PLEs act by inhibiting the production of essential phage proteins and by rupturing the infected bacterial cell before all progeny phage complete their replication cycle. To understand PLE activity in mechanistic detail we will pursue the following specific aims: 1) We will define the regulatory network that permits the rapid stimulation of PLE activity when V. cholerae is under attack by phage and determine how specificity is imparted onto PLE-phage interactions. 2) We will determine how PLE interferes with the ability of phage to produce essential proteins. Under this aim we will use a combination of functional genomic approaches and mutational analyses to separate this aspect of PLE activity from PLE-mediated cell lysis. 3) We will determine the molecular basis for PLE-mediated bacterial cell lysis. We will characterize suppressors that are insensitive to cytotoxic PLE-encoded products to understand how PLE efficiently kills phage-infected V. cholerae. The proposed studies will establish how phage predation shapes the genome of epidemic V. cholerae. This knowledge will enhance our understanding of phage-mediated perturbations to microbial populations in healthy and diseased states, and further our ability to manipulate these communities for therapeutic or prophylactic benefit.