Smith William P J, Davit Yohan, Osborne James M, Kim Wook, Foster Kevin R, Pitt-Francis Joe M
Department of Computer Science, University of Oxford, Oxford OX1 3QD, United Kingdom.
Institut de Mécanique des Fluides de Toulouse (IMFT), Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Institut National Polytechnique de Toulouse (INPT), Université Paul Sabatier (UPS), F-31400 Toulouse, France.
Proc Natl Acad Sci U S A. 2017 Jan 17;114(3):E280-E286. doi: 10.1073/pnas.1613007114. Epub 2016 Dec 30.
The clearest phenotypic characteristic of microbial cells is their shape, but we do not understand how cell shape affects the dense communities, known as biofilms, where many microbes live. Here, we use individual-based modeling to systematically vary cell shape and study its impact in simulated communities. We compete cells with different cell morphologies under a range of conditions and ask how shape affects the patterning and evolutionary fitness of cells within a community. Our models predict that cell shape will strongly influence the fate of a cell lineage: we describe a mechanism through which coccal (round) cells rise to the upper surface of a community, leading to a strong spatial structuring that can be critical for fitness. We test our predictions experimentally using strains of Escherichia coli that grow at a similar rate but differ in cell shape due to single amino acid changes in the actin homolog MreB. As predicted by our model, cell types strongly sort by shape, with round cells at the top of the colony and rod cells dominating the basal surface and edges. Our work suggests that cell morphology has a strong impact within microbial communities and may offer new ways to engineer the structure of synthetic communities.
微生物细胞最明显的表型特征是其形状，但我们并不清楚细胞形状如何影响被称为生物膜的密集群落，许多微生物生活在生物膜中。在这里，我们使用基于个体的建模方法来系统地改变细胞形状，并研究其在模拟群落中的影响。我们在一系列条件下让具有不同细胞形态的细胞相互竞争，并探究形状如何影响群落中细胞的分布模式和进化适应性。我们的模型预测，细胞形状将强烈影响细胞谱系的命运：我们描述了一种机制，通过这种机制，球菌（圆形）细胞会上升到群落的上表面，从而导致一种对适应性至关重要的强大空间结构。我们使用大肠杆菌菌株通过实验来检验我们的预测，这些菌株生长速率相似，但由于肌动蛋白同源物MreB中的单个氨基酸变化而在细胞形状上有所不同。正如我们的模型所预测的，细胞类型按形状强烈分类，圆形细胞位于菌落顶部，杆状细胞则主导基部表面和边缘。我们的工作表明，细胞形态在微生物群落中具有强大影响，并可能为设计合成群落的结构提供新方法。
