Many bacteria communicate using diffusible pheromone signals known as autoinducers. When the autoinducer concentration reaches a threshold, which requires a minimum population density or ‘quorum’, the bacteria activate specific gene regulatory pathways. Simple diffusion of autoinducer can activate quorum-dependent pathways in cells that are located at substantial distances from the secreting source. However, modeling has predicted that autoinducer diffusion, coupled with positive feedback regulation in autoinducer synthesis, could also allow a quorum-regulated behavior to spread more rapidly through a population by moving as a self-sustaining front at constant speed. Here we show that such propagation can occur in a population of bacteria whose quorum pathway operates under its own natural regulation. We find that in unstirred populations of Vibrio fischeri, introduction of autoinducer at one location triggers a wavelike traveling front of natural bioluminescence. The front moves with a well-defined speed ∼2.5mm h⁻¹, eventually outrunning the slower diffusional spreading of the initial stimulus. Consistent with predictions from modeling, the wave travels until late in growth, when population-wide activation occurs due to basal autoinducer production. Subsequent rounds of waves, including waves propagating in the reverse direction, can also be observed late in the growth of V. fischeri under natural regulation. Using an engineered, lac-dependent strain, we show that local stimuli other than autoinducers can also elicit a self-sustaining, propagating response. Our data show that the wavelike dynamics predicted by simple mathematical models of quorum signaling are readily detected in bacterial populations functioning under their own natural regulation, and that other, more complex traveling phenomena are also present. Because a traveling wave can substantially increase the efficiency of intercellular communication over macroscopic distances, our data indicate that very efficient modes of communication over distance are available to unmixed populations of V. fischeri and other microbes.

许多细菌使用称为自诱导剂的可扩散信息素信号进行交流。当自诱导剂浓度达到需要最小种群密度或“法定人数”的阈值时，细菌会激活特定的基因调控途径。自诱导剂的简单扩散可以激活离分泌源很远的细胞中的群体依赖途径。然而，建模预测，自诱导剂扩散与自诱导剂合成中的正反馈调节相结合，也可以通过以恒定速度作为自我维持的前沿移动，使群体调节行为在种群中更快地传播。在这里，我们表明这种传播可以发生在一群细菌中，这些细菌的群体途径在其自身的自然调节下运行。我们发现，在未搅拌的人群中费氏弧菌，在一个位置引入自诱导剂会触发自然生物发光的波浪状行进前沿。前端以明确定义的速度移动~2.5mm h ^-1，最终超过初始刺激的较慢扩散扩散。与建模的预测一致，该波一直传播到生长后期，此时由于基础自诱导剂的产生而发生了全人群激活。随后的几轮波，包括反向传播的波，也可以在V增长的后期观察到。自然调节下的fischeri。使用经过工程设计的lac依赖应变，我们表明除了自诱导剂之外的局部刺激也可以引起自我维持的传播反应。我们的数据表明，通过简单的群体信号数学模型预测的类波动力学很容易在细菌种群中检测到，它们在自身的自然调节下起作用，并且还存在其他更复杂的传播现象。因为行波可以显着提高宏观距离上的细胞间通信效率，我们的数据表明，非常有效的远距离通信模式可用于未混合的V群体。fischeri和其他微生物。