Bihary Dóra, Tóth Marietta, Kerényi Ádám, Venturi Vittorio, Pongor Sándor
Pázmány Péter Catholic University, 1083, Budapest, Hungary.
J Mol Model. 2014 Jul;20(7):2248. doi: 10.1007/s00894-014-2248-y. Epub 2014 Jun 19.
Quorum sensing (QS) is a process of bacterial communication and cooperation mediated by the release of jointly exploited signals and "public goods" into the environment. There are conflicting reports on the behavior of mutants deficient in the release of these materials. Namely, mutants that appear perfectly viable and capable of outgrowing wild type cells in a closed model system such as a culture flask, may not be viable or invasive on open surfaces such as agar plates. Here we show via agent-based computational simulations that this apparent discrepancy is due to the difference between open and closed systems. We suggest that the experimental difference is due to the fact that wild type cells can easily saturate a well-mixed culture flask with signals and public goods so QS will be not necessary after a certain time point. As a consequence, QS-deficient mutants can continue to grow even after the wild type population has vanished. This phenomenon is not likely to occur in open environments including open surfaces and agar plate models. In other words, even if QS is required for survival, QS deficient mutants may grow faster initially in short term laboratory experiments or computer simulations, while only WT cells appear stable over longer time scales, especially when adaptation to changing environments is important.
群体感应（QS）是一种细菌通讯与合作的过程，通过向环境中释放共同利用的信号和“公共物品”来介导。关于缺乏这些物质释放能力的突变体的行为，存在相互矛盾的报道。具体而言，在诸如培养瓶这样的封闭模型系统中看似完全存活且能够比野生型细胞生长得更好的突变体，在诸如琼脂平板这样的开放表面上可能无法存活或具有侵袭性。在此，我们通过基于主体的计算模拟表明，这种明显的差异是由于开放系统和封闭系统之间的不同。我们认为实验差异是由于野生型细胞能够轻易地使信号和公共物品在充分混合的培养瓶中饱和，所以在某个时间点之后群体感应将不再必要。结果，即使野生型群体已经消失，群体感应缺陷型突变体仍能继续生长。这种现象在包括开放表面和琼脂平板模型在内的开放环境中不太可能发生。换句话说，即使群体感应对于生存是必需的，群体感应缺陷型突变体在短期实验室实验或计算机模拟中最初可能生长得更快，而只有野生型细胞在更长的时间尺度上显得稳定，特别是在适应不断变化的环境很重要的情况下。
