Phan Trung V, Mattingly Henry H, Vo Lam, Marvin Jonathan S, Looger Loren L, Emonet Thierry
Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT.
Center for Computational Biology, Flatiron Institute, New York, NY.
bioRxiv. 2023 Jun 5:2023.06.01.543315. doi: 10.1101/2023.06.01.543315.
Chemotactic bacteria not only navigate chemical gradients, but also shape their environments by consuming and secreting attractants. Investigating how these processes influence the dynamics of bacterial populations has been challenging because of a lack of experimental methods for measuring spatial profiles of chemoattractants in real time. Here, we use a fluorescent sensor for aspartate to directly measure bacterially generated chemoattractant gradients during collective migration. Our measurements show that the standard Patlak-Keller-Segel model for collective chemotactic bacterial migration breaks down at high cell densities. To address this, we propose modifications to the model that consider the impact of cell density on bacterial chemotaxis and attractant consumption. With these changes, the model explains our experimental data across all cell densities, offering new insight into chemotactic dynamics. Our findings highlight the significance of considering cell density effects on bacterial behavior, and the potential for fluorescent metabolite sensors to shed light on the complex emergent dynamics of bacterial communities.
趋化细菌不仅能在化学梯度中导航，还能通过消耗和分泌引诱剂来塑造它们的环境。由于缺乏实时测量趋化引诱剂空间分布的实验方法，研究这些过程如何影响细菌种群动态一直具有挑战性。在这里，我们使用一种针对天冬氨酸的荧光传感器，在集体迁移过程中直接测量细菌产生的趋化引诱剂梯度。我们的测量结果表明，用于集体趋化细菌迁移的标准帕特拉克-凯勒-西格尔模型在高细胞密度下会失效。为了解决这个问题，我们对模型提出了修改，考虑了细胞密度对细菌趋化性和引诱剂消耗的影响。通过这些改变，该模型解释了我们在所有细胞密度下的实验数据，为趋化动力学提供了新的见解。我们的研究结果突出了考虑细胞密度对细菌行为影响的重要性，以及荧光代谢物传感器揭示细菌群落复杂涌现动态的潜力。
