Abstract：
Here, employing computer simulation tools, we present a study on the development of a bacterial biofilm from a single starter cell on a flat inert surface overlaid by an aqueous solution containing nutrients. In our simulations, surface colonization involves an initial stage of two-dimensional cell proliferation to eventually transition to three-dimensional growth leading to the formation of biofilm colonies with characteristic three-dimensional semi-ellipsoids shapes. Thus, we have introduced the influence of the nutrient concentration on bacterial growth, and calculated the cell growth rate as a function of nutrient uptake, which in turn depends on local nutrient concentration in the vicinity of each bacterial cell. Our results show that the combination of cell growth and nutrient uptake and diffusion leads to the formation of stratified colonies containing an inner core in which nutrients are depleted and cells cannot grow or divide, surrounded by an outer, shallow crust in which cells have access to nutrients from the bulk medium and continue growing. This phenomenon is more apparent at high uptake rates that enable fast nutrient depletion. Our simulations also predict that the shape and internal structure of the biofilm are largely conditioned by the balance between nutrient diffusion and uptake.
摘要：
这里,采用计算机模拟工具，我们提出了一个细菌生物膜的发展的研究，从一个单一的启动细胞在一个平坦的惰性表面覆盖的水溶液含有营养物质。在我们的模拟中,表面定植涉及二维细胞增殖的初始阶段，最终过渡到三维生长，导致形成具有特征性三维半椭球形状的生物膜菌落。因此，我们介绍了营养浓度对细菌生长的影响，并计算了细胞生长速率作为营养吸收的函数，这又取决于每个细菌细胞附近的局部营养浓度。我们的结果表明，细胞生长与营养吸收和扩散的结合导致形成分层菌落，其中含有内核，营养物质耗尽，细胞无法生长或分裂，被一个外部包围，浅壳，细胞可以从散装培养基中获得营养并继续生长。这种现象在高吸收速率下更为明显，可以快速消耗养分。我们的模拟还预测，生物膜的形状和内部结构在很大程度上取决于养分扩散和吸收之间的平衡。
