The dissertation is devoted to the study of physicochemical, structural, and functional features of cell envelope structures (cell wall (CW), extracellular matrix (ECM), and cytoplasmic membrane (CM)), which play a role in the resistance of microorganisms to stress factors and to create a model of regulation of biosynthesis of the components of CW, ECM, and CM by physical factors. Various chemical and physical factors (nanoparticles, antibiotics, genotoxic compounds, radiofrequency electromagnetic fields (RF-EMF)) caused changes of the cell envelope structures of bacterial and yeast cells. The effect depended on the species and yeast Saccharomyces cerevisiae cell envelopes changed in response to the wide range of factors, including RF-EMF of 40,68 MHz (15 W and 30 W), and 1871 MHz (0.1-10 mkW/cm2), without lacking cell viability. There was a high correlation (up to 99%) between the levels of expression of some CW-proteins (Flo11 and Cwp1) and the content of sugars in the CW and ECM, and with the content of fatty acids and sterols in membranes. In addition, the content of major sugars (glucose and mannose) of CW and ECM changes in a dependent manner indicating an existence of a strong link between these two structures. All these indicate that CW, ECM, and CM form a single system of cell protection from a wide range of stressors. The content of N-acetylglucosamine, N-acetylgalactosamine and Nneuraminic acid in the CW and ECM influence osmotolerance, mechanical stability, and survival of S. cerevisiae cells under the action of peroxide and acidic stresses, genotoxic compounds, and antibiotics. The mechanical properties (stiffness) of yeast cells depend both on the content of CW-proteins and sugars of the CW and ECM. It was found that ergosterol does not play a decisive role in cell resistance to stresses, while the content of two other sterols (silane,[[(3-β-22E)-ergosta-7,22-diene-3-yl] oxy]trimethyl-, and 5-Xi-ergost-7-en-3-β-(trimethylsiloxy)-) significantly correlate with the cell viability under various chemical stresses. S. cerevisiae resistance to stresses is mediated by an activity of polyphosphatases PPN1 and PPX1. Both enzymes participate in the processes of cell response to various stresses, and the PPN1 was shown to be a trigger of the process of adaptive response. The deficiency of cells on the PPN1 and/or PPX1 impact genome stability, gene expression, adhesive properties, and antibiotic resistance of the yeast cells under the action of chemical stresses and RF-EMFs (40.68 MHz, 1871 MHz, and 57-62.5 GHz). Under the simultaneous action of a complex of stress factors, the biological response form to the action of factor with the highest cyto- and genotoxic potential. The biological action of the RF-EMF of meter wave band (40.68 MHz) causes
changes in various parts of the cellular organization but cause no lethal effects. This type of EMF stimulated adaptive response process in yeast cells resulting in an increased resistance of exposed cells to other stresses. RF-EMF of centimeter
(1871 MHz) and millimeter (57-62.5 GHz) wave bands has cyto- and genotoxic potential, has mutagenic effect, and decrease cell viability. The mechanism of action of the RF-EMFs based on an ability to increase the content of intracellular reactive
oxygen species, which, in turn, lead to disruption of protein function, structure and stability of DNA, change intracellular osmolarity and pH that serves as a signal to activate appropriate reparation processes and changes in structure and properties of CW, ECM, and CM, etc. The proposed mechanism of biological action of the RFEMFs can be applied to regulate the composition of cell wall, extracellular matrix, and cytoplasmic membrane.
