Department of Biochemistry, Stanford University, Stanford, California 94305, USA.
Phys Rev Lett. 2010 Jun 11;104(23):238102. doi: 10.1103/PhysRevLett.104.238102. Epub 2010 Jun 8.
Tracking of fluorescently labeled chromosomal loci in live bacterial cells reveals a robust scaling of the mean square displacement (MSD) as τ(0.39). We propose that the observed motion arises from relaxation of the Rouse modes of the DNA polymer within the viscoelastic environment of the cytoplasm. The time-averaged and ensemble-averaged MSD of chromosomal loci exhibit ergodicity, and the velocity autocorrelation function is negative at short time lags. These observations are most consistent with fractional Langevin motion and rule out a continuous time random walk model as an explanation for anomalous motion in vivo.
在活细菌细胞中追踪荧光标记的染色体位置揭示了均方位移（MSD）随 τ（0.39）的稳健缩放。我们提出，观察到的运动源于 DNA 聚合物在细胞质粘弹性环境中的 Rouse 模式的弛豫。染色体位置的时间平均和总体平均 MSD 表现出遍历性，并且在短时间滞后时速度自相关函数为负。这些观察结果与分数朗之万运动最一致，并排除了连续时间随机行走模型作为体内异常运动的解释。
