Jose Ajesh, Pérez-Estay Benjamín, Bendori Shira Omer, Eldar Avigdor, Kearns Daniel B, Ariel Gil, Be'er Avraham
The Albert Katz International School for Desert Studies, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Midreshet Ben-Gurion, Israel.
Laboratoire PMMH-ESPCI Paris, PSL Research University, Sorbonne University, University Paris-Diderot, 7, Quai Saint-Bernard, Paris, 75005, France.
ArXiv. 2024 Nov 26:arXiv:2411.17842v1.
Bacterial swarming is a complex phenomenon in which thousands of self-propelled rod-shaped cells move coherently on surfaces, providing an excellent example of active matter. However, bacterial swarming is different from most studied examples of active systems because single isolated cells do not move, while clusters do. The biophysical aspects underlying this behavior are unclear. In this work we explore the case of low local cell densities, where single cells become temporarily immobile. We show that immobility is related to local depletion of liquid. In addition, it is also associated with the state of the flagella. Specifically, the flagellar bundles at (temporarily) liquid depleted regions are completely spread-out. Our results suggest that dry models of self-propelled agents, which only consider steric alignments and neglect hydrodynamic effects, are oversimplified and are not sufficient to describe swarming bacteria.
细菌群体游动是一种复杂现象，其中数千个自行推进的杆状细胞在表面上协同移动，这是活性物质的一个典型例子。然而，细菌群体游动与大多数已研究的活性系统例子不同，因为单个分离的细胞不会移动，而细胞簇会移动。这种行为背后的生物物理方面尚不清楚。在这项工作中，我们探讨了局部细胞密度较低的情况，此时单个细胞会暂时静止不动。我们表明，静止不动与液体的局部耗尽有关。此外，它还与鞭毛的状态有关。具体而言，（暂时）液体耗尽区域的鞭毛束完全展开。我们的结果表明，仅考虑空间排列而忽略流体动力学效应的自推进体的干燥模型过于简化，不足以描述群体游动的细菌。
