Department of Mathematics, State University of New York at New Paltz, New York, NY, USA.
Department of Mathematics, University of Iowa, Iowa City, IA, USA.
Bull Math Biol. 2021 Nov 27;84(1):9. doi: 10.1007/s11538-021-00965-6.
Bacteria are often exposed to multiple stimuli in complex environments, and their efficient chemotactic decisions are critical to survive and grow in their native environments. Bacterial responses to the environmental stimuli depend on the ratio of their corresponding chemoreceptors. By incorporating the signaling machinery of individual cells, we analyze the collective motion of a population of Escherichia coli bacteria in response to two stimuli, mainly serine and methyl-aspartate (MeAsp), in a one-dimensional and a two-dimensional environment, which is inspired by experimental results in Y. Kalinin et al., J. Bacteriol. 192(7):1796-1800, 2010. Under suitable conditions, we show that if the ratio of the main chemoreceptors of individual cells, namely Tar/Tsr, is less than a specific threshold, the bacteria move to the gradient of serine, and if the ratio is greater than the threshold, the group of bacteria moves toward the gradient of MeAsp. Finally, we examine the theory with Monte Carlo agent-based simulations and verify that our results qualitatively agree well with the experimental results in Y. Kalinin et al. (2010).
细菌经常在复杂的环境中暴露于多种刺激下，它们高效的趋化决策对于在其原生环境中生存和生长至关重要。细菌对环境刺激的反应取决于它们相应的趋化受体的比例。通过整合单个细胞的信号机制，我们分析了受两种刺激（主要是丝氨酸和甲基天冬氨酸（MeAsp））影响的大肠杆菌种群在一维和二维环境中的集体运动，这是受 Y. Kalinin 等人的实验结果启发的，J. Bacteriol. 192(7):1796-1800, 2010。在适当的条件下，如果单个细胞的主要趋化受体 Tar/Tsr 的比例小于特定阈值，则细菌会向丝氨酸梯度移动，如果比例大于阈值，则细菌群体会向 MeAsp 梯度移动。最后，我们用基于蒙特卡罗代理的模拟来检验这个理论，并验证了我们的结果与 Y. Kalinin 等人的实验结果（2010）定性上非常吻合。
