Salman H, Zilman A, Loverdo C, Jeffroy M, Libchaber A
Center for Studies in Physics and Biology, The Rockefeller University, New York, New York 10021, USA.
Phys Rev Lett. 2006 Sep 15;97(11):118101. doi: 10.1103/PhysRevLett.97.118101. Epub 2006 Sep 11.
We study the behavior of a bacterial culture in a one-dimensional temperature gradient. The bacteria first accumulate near their natural temperature due to thermotaxis. The maximum of the bacterial density profile then drifts to lower temperature with a velocity proportional to the initial concentration of bacteria (typical velocity 0.5 microm/sec). Above a critical concentration of 10(8) cells/cm(3), a new mode develops from the initial accumulation in the form of a sharp pulse moving at a faster velocity ( approximately 3.5 microm/sec). The time of development of this mode diverges as the concentration approaches its critical value. This mode is a result of a positive feedback mechanism provided by interbacterial communication. A theoretical model shows good agreement with the experimental results.
我们研究了细菌培养物在一维温度梯度中的行为。由于趋温性，细菌首先在其天然温度附近聚集。然后，细菌密度分布的最大值以与细菌初始浓度成正比的速度（典型速度为0.5微米/秒）向较低温度漂移。当细胞浓度超过临界浓度10⁸个/立方厘米时，一种新的模式从初始聚集中发展出来，表现为一个快速移动的尖锐脉冲（速度约为3.5微米/秒）。随着浓度接近其临界值，这种模式的发展时间会发散。这种模式是细菌间通讯提供的正反馈机制的结果。一个理论模型与实验结果显示出良好的一致性。
