[Study of the function of multienzyme systems of Escherichia coli cellular structures in organic media microemulsions by (31)P-NMR and spin probing]. / Issledovanie raboty mul'tifermentnykh sistem kletochnykh struktur Escherichia coli v mikroémul'sionnykh organicheskikh sredakh metodami (31)P-IaMR i spinovogo zondirovaniia.

Dynamics of substrate pools and level of inorganic phosphate P(i) in the course of glucose-6-phosphate (G6P) utilization by Escherichia coli have been studied by 31P NMR and EPR methods on cells immobilised in a three component water-in-oil microemulsion composed from tridecane, nonionic surfactant Tween 81 and a low amount of water. The state of the electron transport chain in cell membranes has been evaluated on the basis of reduction rates of exogenous nitroxide radicals. Low water activity a(w) in the external microemulsion appears to inhibit, to some extent, glycolytic enzymes and electron transport proteins in the membrane structures without disturbing the membrane integrity and solubilization of lipoproteins in reverse micelles. Enzyme activity has been restricted by the micellar substrate diffusion and by decrease in water activity a(w) in the course of the extensive molecular interchange of bound water between the external microemulsion phase and the internal cell structures.

[Physiological activity of Escherichia coli cells studied by the spin exchange method]. / Izuchenie fiziologicheskoi aktivnosti kletok Escherichia coli metodom spinovogo obmena.

The respiration and reducing activity of Escherichia coli M-17 cells was studied at physiological temperatures using the phenomenon of spin exchange between water-soluble nitroxyl radicals and molecular oxygen in liquid bacterial media. The peak intensity of the EPR signal from nitroxyl probes was characterized by a two-stage kinetics. The first stage was due to the rapid uptake of dissolved O2 whereas the second stage was caused by the anaerobic reduction of free radicals. The maximal rates of respiration and radical reduction were found at 45 to 55 degrees C. The rate of cell respiration changed when lipids underwent a gel-liquid crystal structural transition.

[Interaction of divalent copper ions with the cell surface of Escherichia coli studied by spin exchange]. / Izuchenie vzaimodeistviia ionov dvukhvalentnoi medi s kletochnoi poverkhnost'iu Escherichia coli metodom spinovogo obmena.

The binding of cupric ions to the surface ionogenic groups of Escherichia coli was studied by the method of spin exchange. The formation of coordination complexes between these groups and cupric ions inhibited the physiological activity of the cells by interfering with the operation of their electron-transport chain.