Golovlev E L
Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino, Moscow, Russia.
Mikrobiologiia. 1998 Mar-Apr;67(2):149-55.
This review analyzes data available in the literature and the author's own data on the phenotypic variability of bacteria that occurs within the framework of a genotype unchanging in terms of the genetic information stored. This variability is a form of bacterial adaptation to an unstable environment and results from a specific form of natural selection. This phenomenon arose evolutionarily not as a mechanism to provide genetic diversity for the divergence process but as a mechanism of species stabilization; therefore, it was termed phenotype metastability. It includes, as specific variants, processes known as phase and antigenic variations, R-S-M dissociation, phenotype conversion, etc. The mechanisms of phenotype metastability are extremely diverse. They include alternative expression (of the switch on-switch off type) of individual genes or small groups of genes; variation in the composition of synthesized proteins controlled at the level of transcription; expression of complex phenotypes adapted to different environmental conditions that involves phage transposition, reading-frame-shift mutations, etc. The phenomenon of phenotype metastability is widespread among bacteria.
本综述分析了文献中可用的数据以及作者自己关于细菌表型变异性的数据,这种变异性发生在遗传信息储存方面基因型不变的框架内。这种变异性是细菌适应不稳定环境的一种形式,是特定形式自然选择的结果。这种现象在进化过程中出现,并非作为为分化过程提供遗传多样性的机制,而是作为物种稳定的机制;因此,它被称为表型亚稳定性。作为特定变体,它包括诸如相位和抗原变异、R-S-M解离、表型转换等已知过程。表型亚稳定性的机制极其多样。它们包括单个基因或小基因群的交替表达(开关型);在转录水平控制的合成蛋白质组成的变化;涉及噬菌体转座、移码突变等适应不同环境条件的复杂表型的表达。表型亚稳定性现象在细菌中很常见。