[Deceleration of vital activity as a universal biochemical mechanism ensuring adaptation of microorganisms to stress factors: a review].

The review deals with a major problem of contemporary biology, i.e., the strategy of persistence of organisms affected by stressors. The primary mechanism of biochemical adaptation of cells is their transition to a specific surviving state, which is characterized by deceleration of vital activity (DVA), a process related to decreased metabolism. According to the latest classification, there are four DVA types: quiescence (endogenous or exogenous), cryptobiosis, anabiosys, and latent life. These states are viewed from a new standpoint, as depending on both the stage of growth and development of the organism and the type of stressor. A brief characterization of cryptobiosis and anabiosys is provided. Quiescence, which is a specific type of DVA, is characterized in greater detail, with emphasis on differences between fungi and bacteria. Endogenous and exogenous quiescence is compared in two types of cells (spores). Changes in the composition of quiescent cells (spores) as compared to their vegetating counterparts involve lipids (membrane-associated and neutral), cytosolic carbohydrates (which serve as a reserve supply of nutritives or act as protectors), water content, RNA/protein synthesis, and cyclic nucleotides (e.g., cAMP). Biochemical mechanisms controlling reversion of DVA (the transition from spores to germinating cells) are also analyzed. In conclusion, consideration is given to the role of DVA in evolution and to the implications of DVA studies for biotechnology, cryogenic preservation, utilization of interstellar space and permafrost territories.