Cells and microorganisms adopt various strategies to migrate in response to different environmental stimuli. To date, many modeling research has focused on the crawling-based Dictyostelium discoideum (Dd) cells migration induced by chemotaxis, yet recent experimental results reveal that even without adhesion or contact to a substrate, Dd cells can still swim to follow chemoattractant signals. In this paper, we develop a modeling framework to investigate the chemotaxis induced amoeboid cell swimming dynamics. A minimal swimming system consists of one deformable Dd amoeboid cell and a dilute suspension of bacteria, and the bacteria produce chemoattractant signals that attract the Dd cell. We use the mathematical amoeba model to generate Dd cell deformation and solve the resulting low Reynolds number flows, and use a moving mesh based finite volume method to solve the reaction–diffusion–convection equation. Using the computational model, we show that chemotaxis guides a swimming Dd cell to follow and catch bacteria, while on the other hand, bacterial rheotaxis may help the bacteria to escape from the predator Dd cell.

细胞和微生物采用各种策略来响应不同的环境刺激。迄今为止，许多建模研究都集中在由趋化性诱导的基于爬行的盘基网柄菌(Dd) 细胞迁移上，但最近的实验结果表明，即使没有粘附或接触底物，Dd 细胞仍然可以游动以跟随趋化信号。在本文中，我们开发了一个建模框架来研究趋化性诱导的变形虫细胞游泳动力学。一个最小的游泳系统由一个可变形的 Dd 变形虫细胞和稀释的细菌悬浮液组成，细菌产生吸引 Dd 细胞的化学引诱信号。我们使用数学变形虫模型生成 Dd 单元变形并求解由此产生的低雷诺数流动，并使用基于移动网格的有限体积法求解反应-扩散-对流方程。使用计算模型，我们表明趋化性引导游泳的 Dd 细胞跟随和捕捉细菌，而另一方面，细菌的趋化性可能帮助细菌逃离捕食者 Dd 细胞。