Extracellular membrane vesicles derived from Komagataeibacter oboediens exposed on the International Space Station fuse with artificial eukaryotic membranes in contrast to vesicles of reference bacterium.

Membranous Extracellular Vesicles (EVs) of Gram-negative bacteria are a secretion and delivery system that can disseminate bacterial products and interact with hosts and the environment. EVs of nonpathogenic bacteria deliver their contents by endocytosis into eukaryotic cells, however, no evidence exists for a fusion delivery mechanism. Here, we describe the fusion of exposed to space/Mars-like stressors simulated on the International Space Station vesicles (E-EVs) from Komagataeibacter oboediens to different types of model planar membranes in comparison with the EVs of the ground-based reference strain. The most reliable fusion was achieved with PC:PE:ergosterol or sterol-free PC:PE bilayers. The relative permeability ratio (PK+/PCl-) estimated from the shift of zero current potential according to Goldman-Hodgkin-Katz equation consisted of 4.17 ± 0.48, which coincides with preferential cation selectivity of the EV endogenous channels. The increase in membrane potential from 50 mV to 100 mV induced the fusion of E-EVs with all tested lipid compositions. The fusion of model exosomes with planar bilayer lipid membranes was confirmed by separate step-like increases in its conductance. In contrast, the ground-based reference K. oboediens EVs never induced the fusion event. In our study, we show membrane lipidome perturbations and increased protein aggregation occurred in the exposed samples in the harsh environment when outer membranes of K. oboediens acquired the capability of both homo- and heterotypic fusion possibly by altered membrane fluidity and the pore-forming capability.

[The influence of N-stearoylethanolamine on the activity of antioxidant enzymes and on the level of stable NO metabolites in the rat testes and blood plasma at the early stages of streptozotocine-induced diabetes].

The influence of N-stearoylethanolamine was investigated on the activity of enzymes of antioxidant protection and content of stable metabolites of nitric oxide (NO) in the testes and plasma of rats at the early stages of development of streptozotocine-induced diabetes mellitus. It was shown that the activity of superoxide dismutase, catalase is reduced in the plasma and testes of animals with streptozotocin-induced (50 mg/kg) diabetes (blood glucose 8-10 mmol/L). A significant increase in the amount of nitrite and nitrate anions was revealed in the plasma of rats, while only the level of nitrite was significantly changed in the testes of animals. The per os administration of the NSE aqueous suspension in a dose of 50 mg/kg during 10 days to the rats with induced diabetes contributed to the normalization of catalase activity in the testis, which correlated with a decrease in the amount of TBA-reacting products and activity of superoxide dismutase and catalase in the blood plasma of animals; the use of NSE also contributed to the reduction of nitrite content in the gonads and to normalization of both nitrite and nitrate in the blood plasma of rats. The NSE administration to intact animals caused an increase in superoxide dismutase activity and significantly reduced the content of stable NO metabolites in the blood plasma of animals.

[Cardioprotective effect of N-stearoylethanolamine under the anaphylactic shock in guinea pigs].

It was shown for the first time that endogenous cannabimimetic compound N-stearoylethanolamine (NSE) administered at the dose 65 mg/kg of body weight during two weeks before anaphylaxis had cardioprotective properties on the model of anaphylactic shock in the guinea pigs. NSE reliably normalized the content of histamine and nitric oxide, decreased the activity both inducible and constitutive NO-synthases, prevented accumulation of thiobarbituric acid reactive substances (TBARS) and normalized the activity of catalase, superoxide dismutase and glutathione peroxidase in cardiomyocytes of animals under anaphylaxis. About of 70% of the NSE-treated animals survived under the anaphylactic shock. The present work indicates that NSE may influence the allergic reaction of immediate type and can possibly be used for design of a new type of antiallergic preparations and cardioprotective preparations as well.

[Influence of N-palmitoylethanolamine on the phospholipid and fatty acid composition of rat liver in ischemia]. / Vyvchennia vplyvu N-pal'mitoïletanolaminu na sklad fosfolipidiv ta zhyrnykh kyslot pechinky shchuriv za ishemiï

The effect of N-palmitoylethanolamine (NPE, 10(-5) M) on the lipid peroxidation (LPO) processes, phospholipid and fatty acid content in the rat liver at perfusion and ischemia during the liver preservation was estimated. As early as at the 5th min of perfusion by cooled conserving solution "Eurocollins", LPO activation was determined. Simultaneously the content of lysophosphatidylcholine (LPC) and phosphatidylserine increased, the total cholesterol level decreased. The redistribution of saturated and unsaturated fatty acids quantity was detected. The addition of NPE into "Eurocollins" solution reduced the accumulation of malonedialdehyde and LPC, modified the fatty acids content. These effects, evidently, formed the basis of the protective action of NPE on the hepatic tissues under anoxia.

[Effect of carbon dioxide on free radical processes as affected by artificial hypobiosis in rats]. / Vliianie uglekisloty na svobodnoradikal'nye protsessy v usloviiakh iskusstvennogo gipobioza u krys.

High CO2 concentrations in the inspired air have been studied for their effect on the free-radical oxidation of lipids in the lipids in the blood, its serum and mitochondria of the rat liver under artificial hypobiosis. Kinetics of free-radical oxidation of lipids was estimated from the changes in chemiluminescence parameters as well as the content of products which react with thiobarbituric acid. It is found that in animals in the state of artificial hypobiosis the intensity of free-radical oxidation of lipids was rather less as compared with animals which did not fall into hypobiosis because of the exclusion of CO2 from the inspired air. The data obtained permit concluding that the increase of CO2 concentration in the inspired air prevents from the development of the oxidative stress. It is evident that the increase of CO2 in the inspired air occurs before the formation of the adaptational mechanisms, directed to the preventing of lesion of membrane lipids under artificial hypobiosis.