多鞭毛性促进细菌逆流运动
Multiflagellarity facilitates bacterial upstream motility
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中文总结 AI 辅助
本研究通过实验与模拟揭示，多鞭毛性通过稳定近壁停留和剪切驱动的风向标效应促进细菌逆流运动，而非依赖游泳速度。
中文摘要 AI 辅助
逆流游泳驱动细菌的扩散和表面定殖。许多病原体在感染肠道、肺部和泌尿道时会遇到流体流动，因此细菌如何利用其鞭毛来对抗这些流动对疾病和治疗具有重要意义。然而，形态和鞭毛排列如何控制逆流运动仍不清楚。在此，我们通过结合微流控、定向进化、遗传学、全息术和流体动力学模拟来研究趋流性的生物物理决定因素。利用逆流游泳竞争实验，我们发现周毛菌大肠杆菌和肠道沙门氏菌迅速胜过单毛菌铜绿假单胞菌和霍乱弧菌，在上游积累的密度高出多达五个数量级，尽管弧菌的游泳速度快三倍。运动选择实验表明，趋流性随鞭毛数量和长度的增加而增强，这通过过表达主调控因子flhD/C得到证实。三维全息术和单细胞追踪揭示，多鞭毛性稳定了表面停留并促进了风向标效应，该效应使细胞重新定向至上游，这一机制得到了完全解析鞭毛排列和流体-结构相互作用的模拟的进一步支持。这些结果确立了多鞭毛性是逆流导航的关键促进因素，其受近壁停留和剪切驱动的重定向而非游泳速度的支配。
英文摘要
Upstream swimming drives bacterial spreading and surface colonization. Many pathogens encounter fluid flows as they infect the intestines, lungs, and urinary tract, so how bacteria use their flagella to counter these flows matters for disease and treatment. Yet how morphology and flagellar arrangement govern motility against flow remains unknown. Here, we investigate the biophysical determinants of rheotaxis by combining microfluidics, directed evolution, genetics, holography, and hydrodynamics simulations. Using upstream swimming competitions, we find that peritrichous E. coli and S. enterica rapidly outcompete monotrichous P. aeruginosa and V. cholerae, accumulating upstream at densities up to five orders of magnitude higher, even though Vibrio swims three times as fast. Motility selection experiments show that rheotaxis increases with flagellar number and length, confirmed by overexpressing the master regulator flhD/C. Three-dimensional holography and single-cell tracking reveal that multiflagellarity stabilizes surface residence and promotes the weathervane effect that reorients cells upstream, a mechanism further supported by simulations that fully resolve flagellar arrangement and fluid-structure interactions. These results establish multiflagellarity as a key facilitator of upstream navigation, governed by near-wall residence and shear-driven reorientation rather than by swimming speed.
发表机构
- University of Pennsylvania（宾夕法尼亚大学）
- National Institute for Mathematical Sciences（韩国数学科学国立研究所）
- Chung-Ang University（中央大学）
- University of Cincinnati（辛辛那提大学）
机构由 AI 辅助整理，请以论文原文为准。
