Department of Cell Biology and Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, Connecticut 06030-6406, USA.
Phys Rev Lett. 2011 Dec 23;107(26):268101. doi: 10.1103/PhysRevLett.107.268101.
Spirochetes are a unique group of motile bacteria that are distinguished by their helical or flat-wave shapes and the location of their flagella, which reside within the tiny space between the bacterial cell wall and the outer membrane (the periplasm). In Borrelia burgdorferi, rotation of the flagella produces cellular undulations that drive swimming. How these shape changes arise due to the forces and torques that act between the flagella and the cell body is unknown. It is possible that resistive forces come from friction or from fluid drag, depending on whether or not the flagella are in contact with the cell wall. Here, we consider both of these cases. By analyzing the motion of an elastic flagellum rotating in the periplasmic space, we show that the flagella are most likely separated from the bacterial cell wall by a lubricating layer of fluid. This analysis then provides drag coefficients for rotation and sliding of a flagellum within the periplasm.
螺旋体是一组独特的运动细菌，其特征是其螺旋或扁平波形状以及鞭毛的位置，鞭毛位于细菌细胞壁和外膜（周质空间）之间的微小空间内。在伯氏疏螺旋体中，鞭毛的旋转产生细胞波动，从而推动游泳。由于鞭毛和细胞体之间的力和扭矩的作用，这些形状变化是如何产生的尚不清楚。阻力可能来自摩擦或流体阻力，具体取决于鞭毛是否与细胞壁接触。在这里，我们考虑这两种情况。通过分析在周质空间中旋转的弹性鞭毛的运动，我们表明鞭毛很可能与细菌细胞壁之间存在一层润滑的流体层。然后，该分析为鞭毛在周质中旋转和滑动提供了阻力系数。
