Wang Liyun, Fan Daming, Chen Wei, Terentjev Eugene M
School of Food Science and Technology, Jiangnan University, Wuxi 214122, China.
Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, UK.
Sci Rep. 2015 Oct 14;5:15159. doi: 10.1038/srep15159.
In medicine and food industry, bacterial colonisation on surfaces is a common cause of infections and severe illnesses. However, the detailed quantitative information about the dynamics and the mechanisms involved in bacterial proliferation on solid substrates is still lacking. In this study we investigated the adhesion and detachment, the individual growth and colonisation, and the cell size control of Escherichia coli (E. coli) MG1655 on polyethylene terephthalate (PET) surfaces. The results show that the bacterial growth curve on PET exhibits the distinct lag and log phases, but the generation time is more than twice longer than in bulk medium. Single cells in the lag phase are more likely to detach than clustered ones in the log phase; clustered bacteria in micro-colonies have stronger adhesive bonds with surfaces and their neighbours with the progressing colonisation. We show that the cell size is under the density-dependent pathway control: when the adherent cells are at low density, the culture medium is responsible for coordinating cell division and cell size; when the clustered cells are at high population density, we demonstrate that the effect of quorum sensing causes the cell size decrease as the cell density on surfaces increases.
在医学和食品工业中，表面的细菌定植是感染和严重疾病的常见原因。然而，关于细菌在固体基质上增殖的动力学和机制的详细定量信息仍然缺乏。在本研究中，我们研究了大肠杆菌MG1655在聚对苯二甲酸乙二酯（PET）表面的粘附与脱离、个体生长与定植以及细胞大小控制。结果表明，PET表面的细菌生长曲线呈现出明显的延迟期和对数期，但代时比在液体培养基中长两倍多。延迟期的单个细胞比对数期的聚集细胞更容易脱离；随着定植的进行，微菌落中的聚集细菌与表面及其相邻细菌具有更强的粘附键。我们表明，细胞大小受密度依赖性途径控制：当贴壁细胞处于低密度时，培养基负责协调细胞分裂和细胞大小；当聚集细胞处于高群体密度时，我们证明群体感应效应导致细胞大小随着表面细胞密度的增加而减小。
