Veening Jan-Willem, Smits Wiep Klaas, Kuipers Oscar P
Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom.
Annu Rev Microbiol. 2008;62:193-210. doi: 10.1146/annurev.micro.62.081307.163002.
Clonal populations of microbial cells often show a high degree of phenotypic variability under homogeneous conditions. Stochastic fluctuations in the cellular components that determine cellular states can cause two distinct subpopulations, a property called bistability. Phenotypic heterogeneity can be readily obtained by interlinking multiple gene regulatory pathways, effectively resulting in a genetic logic-AND gate. Although switching between states can occur within the cells' lifetime, cells can also pass their cellular state over to the next generation by a mechanism known as epigenetic inheritance and thus perpetuate the phenotypic state. Importantly, heterogeneous populations can demonstrate increased fitness compared with homogeneous populations. This suggests that microbial cells employ bet-hedging strategies to maximize survival. Here, we discuss the possible roles of interlinked bistable networks, epigenetic inheritance, and bet-hedging in bacteria.
微生物细胞的克隆群体在均匀条件下通常表现出高度的表型变异性。决定细胞状态的细胞成分中的随机波动可导致两个不同的亚群，这一特性称为双稳态。通过将多个基因调控途径相互连接，可以很容易地获得表型异质性，有效地形成一种遗传逻辑与门。虽然状态之间的转换可以在细胞的生命周期内发生，但细胞也可以通过一种称为表观遗传继承的机制将其细胞状态传递给下一代，从而使表型状态得以延续。重要的是，与同质群体相比，异质群体可以表现出更高的适应性。这表明微生物细胞采用风险对冲策略来最大化生存几率。在这里，我们讨论相互连接的双稳态网络、表观遗传继承和风险对冲在细菌中的可能作用。
