Peroxidation of lipids caused rearrangements in physical structure of biomembranes as it was shown by a method of fluorescent probes. These structural rearrangements were accompanied by an increase in the viscosity on the surface and in the depth of the phospholipid bilayer. The increase in the viscosity was apparently due to oxidation and to elimination from the phospholipid bilayer of the unsaturated fatty acid residues. Presence of the unsaturated fatty acids in biomembranes decreases their viscosity. The fraction of saturated fatty acids after peroxidation was respectively increased in the bilayer.

Anilino Naphthalenesulfonates↗

PubMedDate not supplied

[Influence of the fermentative cross-seams on the structure of the microsomal membrane].

In rat liver microsomes freezing with subsequent thawing led to irreversible redistribution of protein-lipid packing. This redistribution was detected by a change in the efficiency of energy transfer between protein aromatic groups of membrane protein and lipid-soluble fluorescent probe pyrene. Transglutaminase pretreatment of microsomes prevented the irreversible redistribution. The enzyme is shown to bind no more than 15 per cent of the whole membrane protein. This smaller part of the microsomal protein is supposed to play the decisive role in the movements of its remaining part.

Acyltransferases↗

PubMedDate not supplied

[Fluorescent probe study of the spatial structure of membranes and lipoproteins].

A review is devoted to principles of studies in spatial structure of the model and biological membranes and lipoproteins on the basis of measuring radiationless energy transfer between fluorescent probes and from proteins to the probes. Recently the theory has been developed for energy transfer in membranes of various geometry and in lipoproteins of different size and structure. Special fluorescent probes are designed and made. The measurement procedure was tested in simulated systems and used to study a series of membranes as well as blood plasma lipoproteins of main classes. Everything above-mentioned resulted in obtaining data on the size of protein molecules in membranes and lipoproteins, proteins location relative to the lipid phase, on the surface area of the membranes (isolated and directly in a cell), association of protein molecules, state of near-protein lipid layer, membrane asymmetry, spreading of proteins on the lipoprotein surface, on the cholesterol effect on the lipid bilayer size etc.

Animals↗

PubMedDate not supplied

[Fluorescent probe--a cholesterol analog: localization in plasma lipoproteins and in model lipid particles].

The absorption spectrum of fluorescent probe--a cholesterol analog cholesta-5,7, 9(11)-trien-3 beta-ol has a vibrational structure with the maximum 326 nm. Its fluorescence spectra maximum is 370 nm. The localization of the probe in lipoproteins of high, low and very low density and in lipid spheres is studied. There are measured the areas, which occupied one molecule of cholesterol and phosphatidyl choline on the surface of lipid spheres and the radius of the lipid spheres. The localization of the probe in lipoproteins and lipid spheres is determined. The areas which occupied one molecule of phosphatidyl choline on the surface of lipid sphere is equal to the same area in mono- and bilayers. Cholesterol has the same condensing action on phosphatidyl choline in lipid spheres as in mono- and bilayers. All the probe molecules are localized on the surface of lipid spheres and lipoproteins and the B-ring of the molecule is immersed on 1.3 +/- 0.2 nm relative to polar groups. The hydroxyl group of cholesterol is arranged near the carbonyl group of phospholipid and the formation of the H-bond between these groups is possible.

Cholestenes↗

PubMedDate not supplied

[Determination of the surface area and viscosity of membranes in T- and B-lymphocytes by means of fluorescent probes].

The surface area of lymphocyte membranes was measured by registering Förster's energy transfer on fluorescent probes. Pyrene served as donor, 4-(n-hydroxystyryl)-N-tetradecylpiridinium (HSP) was the acceptor. The surface area B-lymphocyte membranes was shown to be 1,2 times larger than that of T-lymphocytes. The mean value of lymphocyte membranes viscosity was measured using the excimerization effect of pyrene. This value was the same in all the cells investigated Fluorescence of the probe 3-methoxybenzanthrone (MBA) was 2-2.5 times higher in B-lymphocytes and was not proportional to the surface area of T- and B-cells membranes. MBA fluorescence may imply some differences in physical structures of these cells which are not connected with the viscosity of their membrane lipid phase.

Animals↗

PubMedDate not supplied

[Determination of the radius, volume and surface area of plasma lipoproteins using fluorescent probes].

The effect of radiationless energy transfer between the fluorescent probes was used to determine the radius, volume and surface area of the blood plasma lipoprotein. Anthracene and p-terphenyl, distributed over the whole volume of lipids of a lipoprotein particle, and HSPH-14 localized on its surface served as energy donor and acceptor probes. Human blood lipoproteins of very low (LVLD), low (LLD2), and high (LHD2 and LHD3) density were studied. All the fluorescence-measured lipoprotein volumes were rather close to the data resulted from the weight analysis. The surface areas were equal to 230, 210, 400 and 330 m2 per 1 g of lipoprotein and the radii--11, 11, 7.5, 7.2 nm, respectively. All the measurements were made in solutions, without any denaturating effects on lipoprotein, its concentration being 1 mg/ml and lower.

Chemical Phenomena↗

PubMedDate not supplied

[Biosynthetic incorporation of fluorescently labelled fatty acids in Escherichia coli].

Escherichia coli cells were cultivated in a medium containing 1-pyrene butanoic acid, a fluorescent probe. Total lipids were extracted from the cells, and the extract was separated by thin-layer chromatography. The fluorescent fractions were examined using spectrofluorimetry. The starting 1-pyrene butanoic acid was shown to be biosynthetically incorporated into the bacterial lipid. Four fluorescent fractions appeared as a result; the fractions were derivatives of this compound modified in the chromophore and the fatty acid chain. The results indicate that the formation of 1-pyrene butanoic acid fluorescent metabolites can be used for studying the oxidation-reduction systems of the bacterium.

Cell Membrane↗

PubMedDate not supplied

[Water molecule mobility in the surface layer of a membrane recorded with the fluorescent probe 4-dimethylaminochalcone].

A scheme of the location of a fluorescent probe 4-dimethylaminochalcone (DCM) in a phospholipid membrane has been proposed. According to the scheme the DMC dimethylamino group is located near phosphate groups and the oxygen atom--in the carbonyl groups region of phosphatidylcholine molecules. It is shown that DMC fluorescence is dynamically quenched by water molecules in the membrane. Therefore the quantum yield and, partly the position of DMC fluorescence maximum are determined by the water concentration near the probe, by the ability of water molecules to penetrate into the membrane as far as the carbonyl groups of fatty acid residues and by the water mobility in the membrane layer.

Chalcone↗

PubMedDate not supplied

[Detection of the clusters of negative charges on the surface of erythrocyte cytoplasmic membranes by fluorescent probes].

When charges on the membrane surface are distributed unequally and, especially, when they are in clusters, the concept of Goue-Chapman is not valid. Clusters of the negative charges on the cell surface can be detected by the combination of two fluorescent probes and a polycation which is capable of neutralizing the electrostatic field of the cluster. Clusters of the negative charges have been detected on the membranes of erythrocyte ghosts. Protamine was used as polyanion and fluorescent probes ANS and DSM were used as a fluorescent anion and cation, respectively.

Anions↗

PubMedDate not supplied

[Estimation of the density of the surface charge in lipoproteins from human blood plasma].

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Cholesterol↗

PubMedDate not supplied

[Recording of surface charge changes in erythrocyte and model membranes by means of fluorescent probes].

When staining intact erythrocytes with DSM no quenching of its fluorescence with hems in the membrane was observed. The positively charged fluorescent probe DSM is proposed for estimating a relative change of the charge in phospholipid membrane surface, in erythrocyte ghosts, and in the membranes of some non-hemolyzed erythrocytes. Charged ligands induced a change of the bound probe fluorescence corresponding to the changes in the value and symbol of the charge of the membrane surface. By means of DSM and negatively charged probe of ANS interaction between dimedrol and intact erythrocytes and their ghosts was studied. It has been stated that therewith the ANS binding with the erythrocyte membrane increases, while DSM binding decreases, which points to a decrease of efficient negative charge of the cell surface in the presence of dimedrol. On the basis of cytofluorometric data the binding constant of dimedrol with the membrane of intact erythrocytes was determined.

Anilino Naphthalenesulfonates↗

PubMedDate not supplied

[Interaction between the fluorescent probe 1-anilino-naphthalene-8-sulfonate and chloroplasts].

Interaction between fluorescent probe 1-anilino-naphthalene-8-sulphonate (ANS) and chloroplasts was studied. Parameters of ANS binding with membranes and weakly-bound proteins of chloroplasts were determined. It has been shown that at all pH values the increase of quantum yield of ANS fluorescence with the addition of chloroplasts is mainly determined by the interaction between the probe and weakly-bound chloroplast proteins.

Anilino Naphthalenesulfonates↗