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首页> 外文期刊>Proceedings of the National Academy of Sciences of the United States of America >Bacterial rheotaxis
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Bacterial rheotaxis

机译：细菌流变

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摘要

The motility of organisms is often directed in response to environmental stimuli. Rheotaxis is the directed movement resulting from fluid velocity gradients, long studied in fish, aquatic invertebrates, and spermatozoa. Using carefully controlled microfluidic flows, we show that rheotaxis also occurs in bacteria. Excellent quantitative agreement between experiments with Bacillus subtilis and a mathematical model reveals that bacterial rheotaxis is a purely physical phenomenon, in contrast to fish rheotaxis but in the same way as sperm rheotaxis. This previously unrecognized bacterial taxis results from a subtle interplay between velocity gradients and the helical shape of f lagella, which together generate a torque that alters a bacterium's swimming direction. Because this torque is independent of the presence of a nearby surface, bacterial rheotaxis is not limited to the immediate neighborhood of liquid-solid interfaces, but also takes place in the bulk fluid. We predict that rheotaxis occurs in a wide range of bacterial habitats, from the natural environment to the human body, and can interfere with chemotaxis, suggesting that the fitness benefit conferred by bacterial motility may be sharply reduced in some hydrodynamic conditions.
机译：生物的运动性通常是响应环境刺激而定向的。流变是由流体速度梯度引起的定向运动，长期以来在鱼类，水生无脊椎动物和精子中已有研究。使用精心控制的微流体流动，我们表明流变性也发生在细菌中。枯草芽孢杆菌实验与数学模型之间的极佳定量一致性表明，细菌流变行为是纯粹的物理现象，与鱼类的流变行为相反，但与精子的流变行为相同。这种先前无法识别的细菌滑行是由速度梯度和无花果螺旋形之间的微妙相互作用造成的，它们共同产生改变细菌游动方向的扭矩。因为此扭矩与附近表面的存在无关，所以细菌流变作用不仅限于液-固界面的紧邻，而且还发生在本体流体中。我们预测，从自然环境到人体，流变发生在广泛的细菌栖息地中，并且会干扰趋化性，这表明在某些水动力条件下，细菌运动赋予的健身益处可能会急剧降低。

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  • 作者

    Marcos; Henry C. Fu; Thomas R. Powers; Roman Stocker;

  • 作者单位

    School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798, Singapore,Department of Mechanical Engineering, Ralph M. Parsons Laboratory, Massachusetts Institute of Technology, Cambridge,MA 02139;

    Department of Civil and Environmental Engineering, Ralph M. Parsons Laboratory, Massachusetts Institute of Technology, Cambridge,MA 02139,Department of Mechanical Engineering, University of Nevada, Reno, NV 89557;

    Department of Mechanical Engineering, University of Nevada, Reno, NV 89557;

    School of Engineering and Department of Physics, Brown University, Providence, Rl 02912;

  • 收录信息 美国《科学引文索引》(SCI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    low reynolds number; directional motion; chirality;

    机译：雷诺数低;定向运动手性;

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