Kafri Yariv, da Silveira Rava Azeredo
Department of Physics, Technion, Haifa, Israel.
Phys Rev Lett. 2008 Jun 13;100(23):238101. doi: 10.1103/PhysRevLett.100.238101. Epub 2008 Jun 12.
The bacterium E. coli maneuvers itself to regions with high chemoattractant concentrations by performing two stereotypical moves: "runs," in which it moves in near-straight lines, and "tumbles," in which it does not advance but changes direction randomly. The duration of each move is stochastic and depends upon the chemoattractant concentration experienced in the recent past. We relate this stochastic behavior to the steady-state density of a bacterium population, and we derive the latter as a function of chemoattractant concentration. In contrast to earlier treatments, here we account for the effects of temporal correlations and variable tumbling durations. A range of behaviors is obtained that depends subtly upon several aspects of the system -- memory, correlation, and tumbling stochasticity, in particular.
“游动”，即它沿近似直线移动；以及“翻滚”，即它不前进而是随机改变方向。每次运动的持续时间是随机的，并且取决于近期所经历的化学引诱剂浓度。我们将这种随机行为与细菌群体的稳态密度联系起来，并将后者推导为化学引诱剂浓度的函数。与早期的处理方法不同，在这里我们考虑了时间相关性和可变翻滚持续时间的影响。得到了一系列行为，这些行为微妙地取决于系统的几个方面——特别是记忆、相关性和翻滚随机性。
