Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania.
Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania.
Biophys J. 2021 Jun 15;120(12):2454-2460. doi: 10.1016/j.bpj.2021.04.019. Epub 2021 Apr 29.
Using self-trapped Escherichia coli bacteria that have intact flagellar bundles on glass surfaces, we study statistical fluctuations of cell-body rotation in a steady (unstimulated) state. These fluctuations underline direction randomization of bacterial swimming trajectories and plays a fundamental role in bacterial chemotaxis. A parallel study is also conducted using a classical rotation assay in which cell-body rotation is driven by a single flagellar motor. These investigations allow us to draw the important conclusion that during periods of counterclockwise motor rotation, which contributes to a run, all flagellar motors are strongly correlated, but during the clockwise period, which contributes to a tumble, individual motors are uncorrelated in long times. Our observation is consistent with the physical picture that formation and maintenance of a coherent flagellar bundle is provided by a single dominant flagellum in the bundle.
利用固着在玻璃表面上的、具有完整鞭毛束的内共生大肠杆菌细菌，我们研究了在稳定（未受刺激）状态下细胞体旋转的统计涨落。这些涨落强调了细菌游动轨迹的方向随机化，并且在细菌趋化性中起着基本作用。我们还使用经典的旋转测定法进行了平行研究，其中细胞体的旋转是由单个鞭毛马达驱动的。这些研究使我们能够得出一个重要的结论，即在逆时针方向的马达旋转期间（这有助于奔跑），所有的鞭毛马达都强烈相关，但在顺时针方向的旋转期间（这有助于翻滚），各个马达在长时间内是不相关的。我们的观察结果与物理图像一致，即鞭毛束的相干性的形成和维持是由束中的单个主导鞭毛提供的。
