DU Huijing, Xu Zhiliang, Shrout Joshua D, Alber Mark
Department of Applied and Computational Mathematics and Statistics, University of Notre Dame, Notre Dame, IN 46637, USA.
Math Models Methods Appl Sci. 2011;21 Suppl 1:939-954. doi: 10.1142/S0218202511005428.
Experiments have shown that wild type P. aeruginosa swarms much faster than rhlAB mutants on 0.4% agar concentration surface. These observations imply that development of a liquid thin film is an important component of the self-organized swarming process. A multiscale model is presented in this paper for studying interplay of key hydrodynamical and biological mechanisms involved in the swarming process of P. aeruginosa. This model combines a liquid thin film equation, convection-reaction-diffusion equations and a cell-based stochastic discrete model. Simulations demonstrate how self-organized swarming process based on the microscopic individual bacterial behavior results in complicated fractal type patterns at macroscopic level. It is also shown that quorum sensing mechanism causing rhamnolipid synthesis and resulting liquid extraction from the substrate lead to the fast swarm expansion. Simulations also demonstrate formation of fingers (tendrils) at the edge of a swarm which have been earlier observed in experiments.
实验表明，在琼脂浓度为0.4%的表面上，野生型铜绿假单胞菌群体迁移的速度比rhlAB突变体快得多。这些观察结果表明，形成液体薄膜是自组织群体迁移过程的一个重要组成部分。本文提出了一个多尺度模型，用于研究铜绿假单胞菌群体迁移过程中关键的流体动力学和生物学机制之间的相互作用。该模型结合了液体薄膜方程、对流-反应-扩散方程和基于细胞的随机离散模型。模拟结果展示了基于微观个体细菌行为的自组织群体迁移过程如何在宏观层面上产生复杂的分形图案。研究还表明，群体感应机制导致鼠李糖脂的合成，并从底物中提取液体，从而导致群体快速扩张。模拟结果还展示了在群体边缘形成的指状结构（卷须），这在之前的实验中已经观察到。
