The paper presents data on changes in model biomembranes (liposomes, erythrocyte shadows, erythrocytes) used as test objects for determining those areas of concentrations of biologically active substances in which these is no violation of the structure or function of experimental objects. As biologically active substances synthetic ones were selected: plant growth regulator-melafen used in small doses in pre-sowing seed treatment and antioxidant derivatives -phenosan, phenoxan and Ihfans. It was shown by DSC method that phenosan derivatives in concentrations equal to 10 -5 M and more destroy microdomain organization in bilayers of phospholipid multilamellar liposomes and reform protein microdomains in the shadows of erythrocytes. Melafen in small and large concentrations changes polymodally the microdomain organization in the bilayers of phospholipid multilamellar liposomes without destroying the structure and does not affect the protein microdomains in the shadows. Spectral analysis revealed an increase in membrane permeability in isolated whole erythrocytes under the action of melafen in large and small concentrations. The method of small-angle diffraction scattering showed the absence of melafen influence in a wide range of concentrations on the thickness of phospholipid bilayers and the order of their packing in multilamellar liposomes.

The paper presents data on changes in model biomembranes (liposomes, erythrocyte shadows, erythrocytes) used as test objects to determine those ranges of concentrations of biologically active substances in which there is no violation of the structure or function of experimental objects. Melaphene, plant growth regulator used in small doses in seed pre-treatment, and antioxidant phenosan derivatives, phenoxane and IHFANs, have been used as biologically active substances. It was shown by DSC that phenosan derivatives at concentrations equal to 10-5 M and higher destroy the microdomain organization in the bilayers of phospholipid multilamellar liposomes and reshape protein microdomains in the shadows of red blood cells. Melaphene in small and large concentrations changes polymodal the microdomain organization in the bilayers of phospholipid multilamellar liposomes without destroying the structure and does not affect the protein microdomains in the shadows. An increase in the membrane permeability in isolated intact erythrocytes in the presence of melaphene in large and small concentrations has been revealed by means of spectral anaslysis. The method of small-angle diffraction scattering showed the absence of the effect of melaphene in a wide range of concentrations on the thickness of phospholipid bilayers and the order of their packaging in multilamellar liposomes.

Perfluorodecalin increased survival rate of Ehrlich ascites tumor cells under pathological conditions of hypoxia in combination with hyperkalemia. High potassium medium increased the content of lysophospholipids in samples, while in the presence of perfluorodecalin, phosphatidylethanolamine level decreased.

This investigation deals with the structural properties of sarcoplasmic reticulum (SR) membranes. SR is the main Ca2+-pool in the rabbit skeletal muscle. The principal Ca2+-pool functions of the vesicles of fragmented sarcoplasmic reticulum greatly varied depending on the source of the vesicles origin. The heavy vesicles are the fragmented terminal cistern SR, which mainly released Ca2+. The light ones are the fragmented longitudinal tubules SR, which mainly pumped Ca2+. All tested vesicles have some similar and some different structural and functional characteristics that depend on the arrangements of their lipid and protein molecules in the membranes. The lipid-protein relationships were tested with the help of tryptophan fluorescence quenchers.

The effects of melafen (plant growth stimulant) on membrane structure and functions of animal cells were studied. The process of signal transduction from cell surface to intracellular structures and conformation changes in membranes in the presence of this substance were studied by light scatter and differential scanning microcalorimetry. Melafen in a wide range of concentrations (10−13-10−3 M) inhibited Ca2+ signal system involved in the function of Ca2+-dependent K+ and Cl− channels in Ehrlich ascitic carcinoma cells. Being a hydrophilic substance, melafen had little effect on the lipid phase of artificial membranes, but impaired the function state of transformed cell. The importance of studies of transformed cells causes no doubt because of increasing incidence of diseases associated with uncontrolled cell division.

Using differential scanning microcalorimetry, which makes it possible to assess general rearrangements in the domain organization of the membrane, we obtained data on changes in relative heat capacity (J/g K) at the maximum of the heat absorption peak of DMPC caused by a large (10 ‐2 M) melafen concentration. Figure 1 shows thermal denaturation curves (thermograms) of liposomes formed from the individual lipid DMPC with a known phase-transition temperature. It can be seen that the differences between the control and samples containing different concentrations of melafen (10 ‐5 , 10 ‐3 , and 10 ‐2 M) are not significant. The characteristic phase-transition peak at 23.7 ° C did not shift; its amplitude changed only slightly (by 4% in the presence of 10 ‐5 and 10 ‐3 M melafen and by 15% in the presence of 10 ‐2 M melafen). Therefore, melafen at concentrations 10 ‐5 and 10 ‐3 M has no effect on thermal

It has been shown that illumination of rod outer segment suspension in the presence of photosensitizers (methylene blue lambda greater than or equal to 620 nm; retinal 370 less than or equal to lambda less than or equal to 390 nm) results in chemical modification of the lipid and protein components of the photo-receptor membranes. This modification can be registered by accumulation of lipid peroxidation (LPO) products as well as oligomerization of rhodopsin and a decrease of rhodopsin thermal stability. These effects are prevented by 'O2-quenchers and free radical scavengers. It has been found that the electric activity (ERG) of isolated frog retina is inhibited due to photosensitized generation of 'O2 which can be overcome by preliminary addition of 'O2-quenchers and free radical scavengers to the incubation medium. The LPO products are accumulated in the retinae of rats exposed to high intensity light in vivo. It is concluded that 'O2 and LPO are involved in light-induced damage of the retina.