Dubnau David, Losick Richard
Public Health Research Institute, 225 Warren Street, Newark, NJ 07103, USA.
Mol Microbiol. 2006 Aug;61(3):564-72. doi: 10.1111/j.1365-2958.2006.05249.x.
Gene expression in bacteria is traditionally studied from the average behaviour of cells in a population, which has led to the assumption that under a particular set of conditions all cells express genes in an approximately uniform manner. The advent of methods for visualizing gene expression in individual cells reveals, however, that populations of genetically identical bacteria are sometimes heterogeneous, with certain genes being expressed in a non-uniform manner across the population. In some cases, heterogeneity is manifested by the bifurcation into distinct subpopulations, and we adopt the common usage, referring to this phenomenon as bistability. Here we consider four cases of bistability, three from Bacillus subtilis and one from Escherichia coli, with an emphasis on random switching mechanisms that generate alternative cell states and the biological significance of phenotypic heterogeneity. A review describing additional examples of bistability in bacteria has been published recently.
传统上，细菌中的基因表达是通过研究群体中细胞的平均行为来进行的，这导致人们假定在特定的一组条件下，所有细胞都以大致均匀的方式表达基因。然而，可视化单个细胞中基因表达方法的出现揭示出，基因相同的细菌群体有时是异质的，某些基因在整个群体中的表达方式并不均匀。在某些情况下，异质性表现为分为不同的亚群，我们采用常用说法，将这种现象称为双稳态。在这里，我们考虑四个双稳态的例子，三个来自枯草芽孢杆菌，一个来自大肠杆菌，重点关注产生替代细胞状态的随机切换机制以及表型异质性的生物学意义。最近发表了一篇综述，描述了细菌中双稳态的其他例子。
