[Do nitrite ions participate in regulating systems of intra- and intercellular signalling?]. / Uchastvuiut li nitritnye iony v reguliatsii sistem vnutri- i mezhkletochnoi signalizatsii?

Effect of nitrite ions on content of proteins (hemoglobin, albumin and others), peptides (AKTH and endothelin-1, 2) of total alpha-aminonitrogen and cGMP was studied in rat blood. The data obtained suggest that NO2- may be involved in regulation of these physiologically active substances because NO2- are the deposited form of nitric oxide which may regulate the inter- and intracellular signal systems.

[The nitric oxide cycle in mammals and nitrite reducing activity of heme-containing proteins]. / Tsikl okisi azota v organizme mlekopitaiushchikh i nitritreduktaznaia aktivnost' gemsoderzhashchikh belkov.

A nitric oxide cycle is proposed, which explains numerous experimental data demonstrating that under hypoxic conditions synthesis of NO was elevated. Two pathways appear to be fundamental for activation of NO formation: 1) activation of L-arginine utilization as its content was decreased in blood; 2) transfer of heme-containing proteins hemoglobin, myoglobin, cytochrome oxidase and cytochrome P-450 into their deoxy-form, where these proteins are able to reduce NO2- into NO. This suggests that the nitric oxide cycle may be considered as a compensatory mechanism which allowed the various cells to acquire reduced dependence on overloading under conditions of oxygen and energy deficiency.

[The compensatory-adaptive mechanisms in nitrite-induced hypoxia in rats]. / Kompensatorno-prisposobitel'nye mekhanizmy pri nitritnoi gipoksii u krys.

Concentration of blood proteins, alpha-amino nitrogen, cGMP and endothelin-1,2 was studied in rat's blood at nitric hypoxia. The injection of NaNO2 (5 mg/100 g body weight) was followed by decrease in total protein, albumin and hemoglobin content and by sharp increase in methemoglobin and Hb-NO complexes concentration in rat's blood. Simultaneously, the elevation of free amino acids and peptides with m.w. 2500 D in blood was discovered. One of these peptides was the endothelin-1,2, whose concentration increased twice in plasma at nitric hypoxia. The increase in endothelin and cGMP concentrations is mostly linked with activation of compensative mechanisms, arising as a response to high concentrations of nitro compounds and NO in rats.

[Computer analysis of ESR spectra of spin labels in erythrocyte membranes during genetic hypertension in rats]. / Vychislitel'nyi analiz spektrov élektronnogo paramagnitnogo rezonansa spinovykh metok v membranakh éritrotsitov pri spontannoi geneticheskoi gipertenzii krys.

The investigation of spontaneous hypertension by means of SL-technique is reported. Two component ESR spectra of hypertensive and normotensive rats are simulated. The conventional W/S ratio was shown not to be a measure of relative concentration of two label binding sites ("strongly" and "weakly" immobilized), but it represents alterations in line shapes.

[Decrease in the level and enzymatic activity of cytochrome P-450 during diethylnitrosamine metabolism in vivo and in vitro]. / Snizhenie soderzhaniia i fermentativnoi aktivnosti tsitokhroma P-450 v khode metabolizma diétilnitrozamina in vivo i in vitro.

Diethylnitrosamine (DENA) intoxication of rats was accompanied by a reduction of cytochrome P-450 content in the liver, which correlated well with inactivation of cytochrome P-450 during metabolism of DENA in the liver microsomes.

[Liberation of non-penetrating spin labels from erythrocytes and liposomes after treatment with bacterial protein]. / Osvobozhdenie nepronikaiushchikh spinovykh metok iz éritrotsitov i liposom pod deistviem bakterial'nogo belka.

Liberation of non-penetrating spin labels from erythrocytes and liposomes was studied at their interaction with delta-endotoxin of Bacillus thuringiensis israelensis. The yield of non-penetrating spin labels was shown to be a highly sensitive indicator of the disturbance of the membrane barrier function.

[Computer analysis of electron paramagnetic resonance spectra of spin labels in the study of biological membranes]. / Mashinnyi analiz spektrov élektronnogo paramagnitnogo rezonansa spinovykh metok v issledovanii biologicheskikh membran.

Application of computer analysis to ESR spectra of maleimide spin labels in erythrocyte ghosts and ESR spectra of "spin sacks"--erythrocyte ghosts and liposomes containing concentrated solution of non-penetrating spin label was described. The analysis of the ESR spectra of spin labels gives exhausting information about the parameters of spin hamiltonian, peculiarities of the movement of nitroxyl radicals and their distribution between the cell and medium.

[Effect of indoleacetic acid on the proton conductivity of biological membranes]. / Deistvie indoliluksusnoi kisloty na protonnuiu provodimost' biologicheskikh membran.

The effect of indolylacetic acid (IAA) on proton conductivity of tylacoid membranes of isolated pea chloroplasts at pH 5.5-8.0 and of artificial phospholipid membranes at pH 7.5 were studied. IAA was shown to decrease the stationary proton gradient value and increase those of the dissociation constant and electron transport rate in chloroplasts, while in the artificial phospholipid membranes it increased the proton conductivity. The membrane lipid phase is supposed to be a possible result of phytohormone action, IAA transporting the protons according to the monomeric mechanism.

[Electron paramagnetic resonance of the F1-H+-ATPase complex and adenosine triphosphate synthesis after its irradiation with visible light]. / Elektronnyi paramagnitnyi rezonans kompleksa F1-H+-ATPazy i sintez adenozintrifosfata pri ego osveshchenii vidimym svetom.

Under F1-ATPase irradiation by visible light two characteristic features of flavin main activities were detected: I/ESR signal g = 2.00 appearance which was in favor of flavin photochemical electron reduction and 2/photostimulated O2 consumption by F1-ATPase. The dependence of ESR signal g = 2.00 intensity on visible light wavelength completely coincided with the same dependence obtained for proteinless model riboflavin + ADP. Flavin localization in proximity of ADP bound in the enzyme active site was suggested. Under F1-ATPase irradiation by light lambda greater than 350 nm ATP synthesis was obtained similar to the proteinless model riboflavin + ADP + Pinorg. In this model endogenous flavin was suggested to serve as a photosensitizer, its photoexcitement being a model of dark energization of F1-ATPase in oxidative phosphorylation.

[The effect of highly-dispersed zinc powder on the functional state of blood components and rat liver mitochondria]. / Vliianie vysokodispersnogo poroshka tsinka na funktsional'noe sostoianie komponentov krovi i mitokhondrii pecheni krys.

The functional state of blood components and liver mitochondria have been investigated by means of ESR method and atomic adsorption spectroscopy. The experimental data indicated that injection of highly dispersed Zn-powder in the concentration of 5 mg/kg of weight did not result in disturbance of mitochondria bioenergetic functions, although the functional state of blood components and the level of metal ions in it were changed.

[Redox regulation in ATP synthesis]. / Okislitel'no-vosstanovitel'naia reguliatsiia v sinteze ATF.

Evidence is considered which points to changes of redox potential of the redox-centres in mitochondria during energization, to high sensitivity of ATP-synthetase to redox agents. Examples of ATP-syntheses in model systems stimulated with an electron are discussed. This stimulation is so efficient that it permits weakening of the bond between phosphorus atom and extremely bad leaving group O- in inorganic phosphate-phosphorylating agent in ATP synthesis during oxidative phosphorylation. The sum of these data suggests that function of the redox-centres found in the coupling site may be the accumulation of the intermediate inducing ADP and Phinorg interactions. The electron pool may serve as an intermediate. Thus the redoxcentre function in the coupling site accepting and accumulating the electrons during energization may be compared with chlorophyll function in photosynthesis. Change of redox potential of redox-centres at energization (by protonation, for example) initiates electron transfer in ATP-synthetase, which by the formation of highly reactive-free radical of ADP provides the occurrence of endergonic reaction of ATP synthesis, i.e. storage of energy as a chemical bond.

[Effect of visible light on the ATP synthetase function of mitochondria]. / Vliianie vidimogo sveta na ATF-sintetaznuiu funktsiiu mitokhondrii.

Dependence of oxidative phosphorylation in rat liver mitochondria on redox state of endogenous flavoenzymes was studied. Regulation of the redox state of endogenous flavins in mitochondria was performed by visible light illumination of lambda = 380 nm in oxygen free as well as in oxygenated media. A decrease of oxidative phosphorylation was obtained at full reduction of flavins (respiratory control and ATP synthesis were measured); this effect was partially recovered when flavin was reoxidized by oxygen. Results of ESR measurements of the signal gl = 2.00 associated with semireduced flavins were in accordance with the appearance of diamagnetically completely reduced form of flavin. These facts may be considered as evidence of the regulative role of flavins in oxidative phosphorylation.

[Free radicals and metal paramagnetic ions of the tissues of rats exposed to gamma irradiation and hormones]. / Svobodnye radikaly i paramagnitnye iony metallov tkanei krys pri gamma-obluchenii i deistvii gormonov.

It was shown that gamma-radiation (8-16 Gy) did not influence the number of paramagnetic centers of hemal (g = 2.42, g = 2.25) and nonhemal (g = 1.94) iron of rat tissues: free radicals were significantly reduced 5 min after 16 Gy irradiation. The combined effect of gamma-radiation (8 Gy) and ubiquinone-9 decreased the number of the above-mentioned ESR signals after 48 h. The number of free radicals in the rat liver, kidneys and spleen was almost twice reduced 28 days following castration. The administration of methyl testosterone increased the free radical amount in the heart and was ineffective in other rat organs.

[Electron spin resonance of phosphorylating and non-phosphorylating submitochondrial particles]. / Elektronnyi paramagnitnyi rezonans fosforiliruiushchikh i nefosforiliruiushchikh submitokhondrial'nykh chastits.

Paramagnetic centres related with the work of ATP-synthetase, found earlier on mitochondria were studied on phosphorylating and non-phosphorylating submitochondrial particles (SMP). A complex doublet signal with half-width 38 . 10(-4) T was shown to be recorded only on actively phosphorylating and oligomycin-inhibited SMP. It was found that the signal components were conditioned by different paramagnetic centres, one of which (g = 2.03) seemed to be the metal centre, more probable non-hemeiron. The nature of the second signal characterized by evenly saturating doublet components with g = 2.03 and g = 2.00 is unclear. Studies of flavin signal saturation have also shown that it consists of two components: one of them--saturating, specific for non-phosphorylating SMP, another--non-saturating, mostly observed in phosphorylating SMP, probably conditioned by flavin--the constituent of ATP-synthetase.

[ESR study of interaction between adenylate kinase, substrates and Mn2+ ions]. / Issledovanie vzaimodeistviia adenilatkinazy a substratami i ionami margantsa metodom élektronnogo paramagnitnogo rezonansa.

Plant adenylate kinase was first investigated by ESR technique at room temperature. In contrast to previous studies the measurement conditions corresponded to maximal enzyme activity. It was shown that adenylate kinase addition provoked Mn2+--adenine nucleotide binary complex distribution and rearrangement of components with the formation of ternary Mn2+--adenine nucleotide--adenylate kinase complex. The same results were obtained in the studies on myokinase from rabbit muscle.