A benzopyrylium dye as a novel effective cationic uncoupler of oxidative phosphorylation.

Benzopyrylium dye BDBP was found to be an effective uncoupler of oxidative phosphorylation. It stimulates state 4 respiration of mitochondria 2-fold at about 2 microM, reveals a maximum stimulation (8-fold) at 30 microM and inhibits the respiration at higher concentrations. BDBP is also an effective proton (hydroxyl) carrier through bilayer lipid membranes (BLM) as is seen from the electrical properties of BLM with BDBP.

[Permeability of bilayer lipid membranes to amphotericin B].

The permeability coefficient of BLM to amphotericin B decreases as cholesterol content of the membrane and KCl concentration of the aqueous medium increases. This effect is supposed to be the result of significant growth of BLM microviscosity caused by sharp increase of BLM half-pores content. The data obtained show the biological effect of amphotericin B to the "two-sided" one.

[Permeability of bilayer lipid membranes to nystatin].

The permeability coefficient of BLM to nystatin was measured as function of cholesterol content of membrane and KCL concentration of aqueous medium. The data obtained were used to demonstrate that leakage of metabolites from microorganisms cytoplasm induced by nystatin may be a result of "two-sided" effect of polyene. This eliminates the known contradication between "two-sided" formation of pores in BLM by nystatin and its "one-sided" biological effect.

[Protonophoric and uncoupling activity of water-soluble pea flavonols].

In the experiments with artificial lipid membranes and mitochondria the watersoluble pea flavonols are demonstrated to possess weak protonophoric and uncoupling activities which correlate with each other. It is concluded that the mechanism of flavonol uncoupling activity is the same as for classical uncouplers. The results support the earlier suggestion that one of the flavonol functions in the plants may be the regulation of the energetics and metabolism.

[Study of the mechanism of action of fasciolocides using bimolecular phospholipid membranes].

The effects of compounds (see article), where M = -S-, -SO-, -SO2- and of some of their derivatives (18 substances) on electroconductivity of bimolecular lipid membranes (BLM) of different composition in 30 mM tris-HCl (pH 7.5) is studied. The results obtained are compared with literature data concerning fasciolocide and toxic effect of these substances.