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复杂液体的胶体性质可增强细菌的运动能力
2022-04-04 12:18

美国明尼苏达大学Xiang Cheng、北京师范大学Xinliang Xu等研究人员合作发现,复杂液体的胶体性质可增强细菌的运动能力。这一研究成果于2022年3月30日发表在国际学术期刊《自然》上。

研究人员表明,在稀释的胶体悬浮液中的鞭毛细菌显示出与稀释的聚合物溶液中的运动行为在数量上相似,特别是普遍的颗粒大小相关的运动能力增强,高达80%,伴随着细菌摆动的强烈抑制。由于胶体的硬球性质,其大小和体积分数在不同的实验中有所不同,这些结果揭示了复杂流体中细菌运动能力增强的长期争议,并表明聚合物动力学可能不是捕捉该现象的关键。一个包含了复杂流体的胶体性质的物理模型定量地解释了细菌在胶体和聚合物流体中的摆动动力学和移动性增强。这些发现有助于理解细菌在复杂流体中的运动行为,这与广泛的微生物过程和复杂环境中的细菌游泳工程有关。
 
据了解,人类微生物组、海洋和土壤生态系统中的微生物的自然栖息地充满了胶体和大分子。这种环境表现出非牛顿流动特性,极大地影响了微生物的运动。尽管简单的牛顿流体中游动的鞭毛细菌的低雷诺数流体动力学已经得到很好的发展,但人们对复杂的非牛顿流体中细菌运动的理解却不那么成熟。即使经过六十年的研究,关于细菌在聚合物溶液中运动能力增强的性质和起源的基本问题仍在辩论之中。
 
附:英文原文
 
Title: The colloidal nature of complex fluids enhances bacterial motility

Author: Kamdar, Shashank, Shin, Seunghwan, Leishangthem, Premkumar, Francis, Lorraine F., Xu, Xinliang, Cheng, Xiang

Issue&Volume: 2022-03-30

Abstract: The natural habitats of microorganisms in the human microbiome, ocean and soil ecosystems are full of colloids and macromolecules. Such environments exhibit non-Newtonian flow properties, drastically affecting the locomotion of microorganisms1,2,3,4,5. Although the low-Reynolds-number hydrodynamics of swimming flagellated bacteria in simple Newtonian fluids has been well developed6,7,8,9, our understanding of bacterial motility in complex non-Newtonian fluids is less mature10,11. Even after six decades of research, fundamental questions about the nature and origin of bacterial motility enhancement in polymer solutions are still under debate12,13,14,15,16,17,18,19,20,21,22,23. Here we show that flagellated bacteria in dilute colloidal suspensions display quantitatively similar motile behaviours to those in dilute polymer solutions, in particular a universal particle-size-dependent motility enhancement up to 80% accompanied by a strong suppression of bacterial wobbling18,24. By virtue of the hard-sphere nature of colloids, whose size and volume fraction we vary across experiments, our results shed light on the long-standing controversy over bacterial motility enhancement in complex fluids and suggest that polymer dynamics may not be essential for capturing the phenomenon12,13,14,15,16,17,18,19,20,21,22,23. A physical model that incorporates the colloidal nature of complex fluids quantitatively explains bacterial wobbling dynamics and mobility enhancement in both colloidal and polymeric fluids. Our findings contribute to the understanding of motile behaviours of bacteria in complex fluids, which are relevant for a wide range of microbiological processes25 and for engineering bacterial swimming in complex environments26,27.

DOI: 10.1038/s41586-022-04509-3

Source: https://www.nature.com/articles/s41586-022-04509-3

Nature:《自然》,创刊于1869年。隶属于施普林格·自然出版集团,最新IF:69.504
官方网址:http://www.nature.com/
投稿链接:http://www.nature.com/authors/submit_manuscript.html


本期文章:《自然》:Online/在线发表

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