Phage Manipulation of Bacterial Quorum-Sensing-Mediated Communication

摘要/项目总结 细菌因引起疾病而声名狼借，并且由于其有益的生物学特性而越来越受到人们的重视。 健康中的角色。细菌可以作为自由游动的细胞或作为表面附着的群落的成员存在， 生物膜生物膜对人体健康特别有害。这些生活方式之间的转换是受控的 通过称为群体感应（QS）的细胞间通信过程。QS依赖于生产、放行、 积累和检测细胞外信号分子称为自诱导物（AI）。QS使细菌能够 协调集体行为，包括生物膜的形成和扩散。一种噬菌体最近在 发现劫持细菌QS AI并使用其中编码的信息来驱动裂解之间的转换 和溶原性，首次报道噬菌体-细菌QS介导的界间通讯。噬菌体QS 称为VqmAPhage的受体使噬菌体能够"调谐"同源宿主QS AI，3，5- 二甲基吡嗪-2-醇（DPO）。这种窃听机制允许噬菌体执行其裂解周期 仅在高宿主细胞密度下，推测最大化噬菌体扩散。此外，这一机制使 驱动宿主细菌生物膜扩散程序的噬菌体。我的目标是了解 以及这种新发现的噬菌体QS交叉通讯过程的生物学意义， 模拟性质：非均匀空间结构的噬菌体-细菌生物膜群落。我假设噬菌体 QS受体在感染后立即产生，提供了进入宿主的第一个指示 细胞密度，使得噬菌体能够在进入时适当地启动裂解或溶原性程序。我会 定义感染后该途径何时被激活。其次，我假设自然的，宿主产生的 vqmA噬菌体表达的诱导剂启动了一个正反馈环，该环促进噬菌体的快速转化 仅在高宿主细胞密度下进入裂解期。我将鉴定vqmA噬菌体的内源性诱导物 转录并探索诱导物在噬菌体和宿主生物学中的作用。最后，我预测噬菌体介导的 裂解主要发生在生物膜的最高细胞密度区域，促进宿主扩散和增加 噬菌体扩散到新的宿主细胞。我将定义空间和时间动态噬菌体QS介导的裂解， 生物膜和我将监测对生物膜、噬菌体传播和宿主细胞扩散的影响。 总的来说，我的工作将定义通过QS发生的噬菌体-细菌界间相互作用。我的发现 也有助于开发新的方法来控制细菌感染，无论是通过噬菌体 治疗、生物膜破坏策略或两种方法的组合。为了实现这一目标， 项目，我将成为分子生物学，细菌遗传学，成像技术，科学写作， 研讨会演讲，教学和指导。作为一名博士后研究员， 将是至关重要的准备我建立自己的独立的学术实验室，专注于调查 噬菌体-细菌群落

ABSTRACT / PROJECT SUMMARY Bacteria are notorious for causing disease and increasingly becoming appreciated for their beneficial roles in health. Bacteria can exist as free-swimming cells or as members of surface-attached communities called biofilms. Biofilms are particularly detrimental to human health. Transitions between these lifestyles are controlled by the cell-cell communication process called quorum sensing (QS). QS relies on the production, release, accumulation, and detection of extracellular signal molecules called autoinducers (AIs). QS enables bacteria to orchestrate collective behaviors including biofilm formation and dispersal. A bacteriophage was recently discovered that hijacks a bacterial QS AI and uses the information encoded in it to drive transitions between lysis and lysogeny, the first report of phage-bacterial QS-mediated inter-kingdom-communication. The phage QS receptor called VqmAPhage enables the phage to “tune into” the accumulation of the cognate host QS AI, 3,5- dimethylpyrazin-2-ol (DPO). This eavesdropping mechanism allows the phage to execute its lytic cycle exclusively at high host cell density, presumably maximizing phage spread. Moreover, this mechanism enables the phage to drive the host bacterial biofilm dispersal program. My aims are to understand the molecular basis and biological significance of this newly-discovered phage QS cross-communication process in contexts that mimic nature: non-uniform spatially structured phage-bacterial biofilm communities. I hypothesize that the phage QS receptor is produced immediately following infection providing incoming phages the first indication of host cell density, enabling the phage to appropriately launch either the lysis or the lysogeny program upon entry. I will define when this pathway is activated following infection. Second, I hypothesize that the natural, host-produced inducer of vqmAPhage expression primes a positive feedback loop that promotes the rapid transition of the phage to the lytic phase exclusively at high host cell density. I will identify the endogenous inducer of vqmAPhage transcription and explore the role of the inducer in phage and host biology. Finally, I predict that phage-mediated lysis occurs primarily at the highest cell density regions of biofilms, promoting both host dispersal and increased phage spread to new host cells. I will define the spatial and temporal dynamics of phage QS-mediated lysis in biofilms and I will monitor the consequences to the biofilm, to phage transmission, and to host cell dispersal. Collectively, my work will define phage-bacterial inter-kingdom interactions that occur through QS. My findings could also contribute to the development of new approaches to control bacterial infections, either through phage therapies, biofilm disruption strategies, or a combination of the two approaches. To accomplish the goals of this project, I will become expert in molecular biology, bacterial genetics, imaging technologies, scientific writing, seminar speaking, teaching, and mentoring. The skills I master as I make discoveries as a postdoctoral fellow will be crucial to prepare me to establish my own independent academic laboratory focused on investigations of phage-bacterial communities.