Switching and Growth for Microbial Populations in Catastrophic Responsive Environments
Switching and Growth for Microbial Populations in Catastrophic Responsive Environments
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DOI：
10.1016/j.bpj.2009.11.049
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发表时间：
2010-04-07
影响因子：
3.4
通讯作者：
Evans, Martin R.
中科院分区：
文献类型：
--
作者：
Visco, Paolo;Allen, Rosalind J.;Evans, Martin R.
相变，即基因表达不同状态之间的随机切换，在微生物中很常见，并且在应对不断变化的环境方面可能很重要。我们使用一个理论模型来评估这种转换是否是一个很好的战略，偶尔发生灾难性事件的环境中的增长。我们发现，开关可以是有利的，但只有当环境是响应微生物种群。在我们的模型中，微生物在两种表型状态之间随机切换，具有不同的生长速率。环境会发生突发性灾害，其概率取决于人口的构成。我们得到了一个简单的人口增长率的分析结果。对于响应环境，出现了两种替代策略。在无切换策略中，种群最大化其瞬时增长率，而不考虑灾难。在切换策略中，微生物切换速率被调整以最小化环境响应。这些策略中哪一个最有利取决于模型的参数。先前的研究表明，当环境在几个状态之间以无响应的方式变化时，微生物切换可能是有利的。在这里，我们展示了一种替代作用，使微生物在灾难性的响应环境中最大限度地提高其增长的相位变化。
Phase variation, or stochastic switching between alternative states of gene expression, is common among microbes, and may be important in coping with changing environments. We use a theoretical model to assess whether such switching is a good strategy for growth in environments with occasional catastrophic events. We find that switching can be advantageous, but only when the environment is responsive to the microbial population. In our model, microbes switch randomly between two phenotypic states, with different growth rates. The environment undergoes sudden catastrophes, the probability of which depends on the composition of the population. We derive a simple analytical result for the population growth rate. For a responsive environment, two alternative strategies emerge. In the no-switching strategy, the population maximizes its instantaneous growth rate, regardless of catastrophes. In the switching strategy, the microbial switching rate is tuned to minimize the environmental response. Which of these strategies is most favorable depends on the parameters of the model. Previous studies have shown that microbial switching can be favorable when the environment changes in an unresponsive fashion between several states. Here, we demonstrate an alternative role for phase variation in allowing microbes to maximize their growth in catastrophic responsive environments.