[Inhibitors of the nitrite oxidation of hemoglobin]. / Ingibitory nitritnogo okisleniia gemoglobina.

Different types of active inhibitors of the reaction of nitrite hemoglobin oxidation have been revealed and studied. The dependence of inhibition of methemoglobin formation, on concentration of inhibitors at pH 5.9 and 7.17 has been determined. Differential absorption spectra of the inhibitors in the presence sodium nitrite in UV and visual light has been studied. The values of oxidation-reduction potentials have been estimated. Possible mechanism of action of the inhibitors has been discussed.

[Effect of cycloheximide and actinomycin D on the phospholipid and neutral lipid content of Cunninghamella japonica]. / Vliianie tsiklogeksimida i aktinomitsina D na soderzhanie fosfolipidov i neitral'nykh lipidov Cunninghamella japonica.

Changes in the composition of neutral lipids and phospholipids were studied during the growth of Cunninghamella japonica under the action of cycloheximide and actinomycin D. The data were used to discuss how the synthesis of enzymes catalysing the formation of individual lipid classes was regulated and whether it would be possible to control the composition of phospholipids and neutral lipids using inhibitors of RNA and protein synthesis. The results are also indicative of a certain correlation between growth phases of the fungus and changes in certain characteristics of membrane lipids.

[Inhibitors of nitrite oxidation of hemoglobin]. / Ingibitory nitritnogo okisleniia gemoglobina.

The effects of sodium benzoate, ascorbic acid and cystein on the kinetics of oxidation of oxyhemoglobin in the presence of sodium nitrite were studied. It was shown that sodium benzoate and ascorbic acid suppress nitrite methemoglobin formation more intensively than cystein. Both compounds can also inhibit nitrite oxidation of intraerythrocyte hemoglobin. Possible mechanisms underlying the inhibiting effects of sodium benzoate, ascorbic acid and cystein are discussed.

[Change in lipid-protein interactions in the membranes of bacteria exposed to gramicidin S]. / Izmenenie lipid-belkovykh vzaimodeistvii v membrane bakterii pri deistvii gramitsidina S

Effect of cyclopeptide antibiotic gramicidin S on some enzymes and physical state of isolated Micrococcus lysodeikticus membranes is studied. Malate and lactate dehydrogenases were monotonously inhibited under the increase of gramicidin S concentration, while the activity of NADH-dehydrogenase firstly decreased and then reversed to the initial level under further increase of gramicidin S concentration. The oxygen uptake under oxidation of NADH and malate with membranes almost completely inhibited by the antibiotic, while the activity of ascorbate-TMPD-oxidase activity slightly inhibited by the same concentration of gramicidin. The addition of Triton X-100 completely eliminated the inhibitory effect of gramicidin on malate dehydrogenase. The introduction into the membrane of spine probes (2,2,6,6-tetramethyl-4-palmitoylamidopiperidine-1-oxile and 2(14-carboxytetradecyl)-2-ethyl-4,4-dimethyl-3-oxyazolidinyloxile) revealed that gramicidin caused the condensation of membrane lipid component. It is suggested that ionic interaction of gramicidin S with membrane phospholipids brings to "a freezing" of lipids which is a direct cause of impairing the activity of membrane respiration enzymes and the change of their position in the lipid matrix, thus inhibiting energy-producing processes in cell.