A Continuous Culturing Device for use in Bacteriophage Evolution

在地表水中，每个海洋微生物大约有10个病毒颗粒，细菌细胞的病毒感染在驱动种群结构方面发挥着重要作用，反过来也是全球碳生物地球化学的基本组成部分。绝大多数海洋细菌和它们的病毒都非常小，而且很稀薄。人们对其共同进化的后果知之甚少。例如，直到最近，人们还认为超小型细菌的大小，如无处不在的Pelagibacter spp。通过“神秘逃逸”避免了病毒感染。然而，在2013年，这个想法被证明是错误的，因为发现了感染全球海洋的Pelagibacter的病毒。这个项目将调查宿主和病毒的共同进化，以及它们是如何受到它们大小的生物学和物理后果以及海洋环境中的生命的影响的。这个项目的目的是调查由于海洋中的流体流动而导致的宿主/病毒大小和复杂的相遇模式的共同进化结果。为了实现这一目标，学生将比较Pelagibacter及其病毒的共同进化与一系列不同大小的宿主和病毒对的共同进化。在普利茅斯海洋实验室的环境单细胞基因组学设施中，将使用单细胞基因组分析和原子力显微镜分别研究共同进化适应，以可视化基因型和表型变化(重点是细胞膜适应)。在第二步，将在一系列不同的流体环境中进行共同进化实验。特别是，通过对分隔的微流体环境的精细控制，将在实验室模拟细菌和病毒在海洋中相遇的不同场景。如果学生感兴趣，这种方法背后的理论考虑可以用来从理论上研究流体流动对共同进化的影响。虽然工作的重点将是实验共同进化，但该项目可能包含不同数量的技术开发和理论工作。经过一段时间的初步培训后，学生将被鼓励与主管一起开发项目设计。

With approximately 10 viral particles for every marine microbe in surface water, viral infection of bacterial cells plays a significant role in driving population structure and, in turn, is a fundamental component of global carbon biogeochemistry. The vast majority of marine bacteria and their viruses are extremely small and dilute. The co-evolutionary consequences thereof are poorly understood. For example, it was thought until recently that the size of ultra-small bacteria such as the ubiquitous Pelagibacter spp. enabled avoidance of viral infection through 'cryptic escape'. Yet, in 2013, this idea was proved false by the discovery of viruses infecting Pelagibacter, which dominate global oceans.This project will investigate the coevolution of host and virus and how they are shaped by the biological and physical consequences of their sizes as well as by life in a marine environment.The aim of this project is to investigate the co-evolutionary consequences of host / virus size and complex encounter patterns due to fluid flow in the ocean. To achieve this goal, the student will compare co-evolution of Pelagibacter and its virus with co-evolution of a range of host and virus pairs with varying size. Co-evolutionary adaptations will be investigated using single-cell genomic analysis and atomic force microscopy to visualise genotypic and phenotypic changes (focusing on cell-membrane adaptations), respectively, within the environmental single cell genomics facility at Plymouth Marine Laboratory.In a second step, co-evolution experiments will be performed in a range of different fluidic environments. In particular, different scenarios of encounters of bacteria and virus in the ocean will be mimicked in the laboratory through the exquisite control of compartmentalised microfluidic environments. The theoretical considerations underlying this approach can be used to study the consequences of fluid flow on co-evolution theoretically if the student is interested.While the focus of the work will be on experimental co-evolution, the project can contain a varying amount of technology development and theory work. Following a period of initial training, the student will thus be encouraged to develop the project design together with the supervisors.