Holz M, Chen S H
Biophys J. 1978 Jul;23(1):15-31. doi: 10.1016/S0006-3495(78)85429-0.
We report the observation of migrating chemotactic bands of Escherichia coli in a buffer solution. The temporal development of the bacterial density profile is observed by the scattered light intensity as the band migrates through a stationary laser beam. We have made a preliminary analysis of the observed band profile with help of the Keller-Segel theory. The model accounts for only some aspects of the observed time evolution of the density profile. The microscopic motility characteristics of the E. coli in the band are simultaneously studied by photon correlation. The measured correlation functions are analyzed to obtain the spatial dependence of the half-width within the band. A simple analytical model is proposed to account for the contribution of the twiddle motion to the correlation function. By analyzing the correlation function as a superposition of straight-line and twiddle motions, we obtain a satisfactory agreement between the theory and the measured angular dependence of the line shape. As a consequence we are able to extract a parameter beta, which measures the average fraction of twiddling bacteria in the center of the band at a given time.
我们报告了在缓冲溶液中观察到的大肠杆菌趋化带迁移现象。当趋化带穿过固定激光束时，通过散射光强度观察细菌密度分布随时间的变化。我们借助凯勒-西格尔理论对观察到的带分布进行了初步分析。该模型仅解释了密度分布随时间演变的某些方面。同时通过光子相关研究了趋化带中大肠杆菌的微观运动特性。分析测量得到的相关函数，以获得带内半高宽的空间依赖性。提出了一个简单的分析模型来解释旋转运动对相关函数的贡献。通过将相关函数分析为直线运动和旋转运动的叠加，我们在理论与测量得到的线形角度依赖性之间取得了令人满意的一致性。因此，我们能够提取出一个参数β，它测量了在给定时间带中心旋转细菌的平均比例。
