Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark.
Department of Biology, University of Copenhagen, DK-2200 Copenhagen, Denmark
Proc Natl Acad Sci U S A. 2018 Jan 9;115(2):337-342. doi: 10.1073/pnas.1708954115. Epub 2017 Dec 19.
Bacteria form colonies and secrete extracellular polymeric substances that surround the individual cells. These spatial structures are often associated with collaboration and quorum sensing between the bacteria. Here we investigate the mutual protection provided by spherical growth of a monoclonal colony during exposure to phages that proliferate on its surface. As a proof of concept we exposed growing colonies of to a virulent mutant of phage P1. When the colony consists of less than [Formula: see text]50,000 members it is eliminated, while larger initial colonies allow long-term survival of both phage-resistant mutants and, importantly, colonies of mostly phage-sensitive members. A mathematical model predicts that colonies formed solely by phage-sensitive bacteria can survive because the growth of bacteria throughout the colony exceeds the killing of bacteria on the surface and pinpoints how the critical colony size depends on key parameters in the phage infection cycle.
细菌形成菌落并分泌包围单个细胞的细胞外聚合物质。这些空间结构通常与细菌之间的协作和群体感应有关。在这里，我们研究了在暴露于在其表面增殖的噬菌体时，单细胞菌落的球形生长提供的相互保护。作为概念验证，我们将生长中的菌落暴露于噬菌体 P1 的一种毒性突变体中。当菌落由少于[公式：见文本]50,000 个成员组成时，它会被消灭，而较大的初始菌落允许噬菌体抗性突变体和重要的主要是噬菌体敏感成员的菌落长期存活。一个数学模型预测，仅由噬菌体敏感细菌形成的菌落可以存活，因为整个菌落中细菌的生长超过了表面细菌的杀伤，并且指出了关键的菌落大小如何取决于噬菌体感染周期中的关键参数。
