Boris G Tenchov

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By means of differential scanning calorimetry and from a review of published data we demonstrate in this work that low-molecular weight kosmotropic substances (water-structure makers) of different chemical structure such as disaccharides, proline, and glycerol have identical effects on the phase behavior of several kinds of phospholipids and glycolipids.(More)
By means of x-ray diffraction we show that several sodium salts and the disaccharides sucrose and trehalose strongly accelerate the formation of cubic phases in phosphatidylethanolamine (PE) dispersions upon temperature cycling through the lamellar liquid crystalline-inverted hexagonal (Lalpha-HII) phase transition. Ethylene glycol does not have such an(More)
By using time-resolved X-ray diffraction we demonstrate that low amounts (5-10 mol%) of a phospholipid with two saturated hydrocarbon acyl chains 14 carbon atoms long and PEG550 chain covalently attached to its phosphoethanolamine polar head group, DMPE(PEG550), induce spontaneous formation of a cubic phase with lattice constant 20.5 nm (cubic aspect #8,(More)
The sonication procedure of preparation of small unilamellar vesicles is modelled as a process of uniform random fragmentation of the lipid aggregates. The vesicle size distribution evolving in this process is shown to be identical with the Weibull extremal probability distribution. Size histograms of sonicated small vesicles of various phospholipid(More)
The role carbohydrate moieties play in determining the structure and energetics of glycolipid model membranes has been investigated by small- and wide-angle X-ray scattering, differential scanning densitometry (DSD), and differential scanning microcalorimetry (DSC). The dependence of a variety of thermodynamic and structural parameters on the(More)
Several new features of the phase diagram of L-dipalmitoylphosphatidylcholine (DPPC)/palmitic acid mixtures in excess water were established by means of static and time-resolved X-ray diffraction, densitometry and differential scanning calorimetry (DSC). At low temperatures, palmitic acid has a biphasic effect on the lamellar subgel phases: at(More)
The phase transitions in fully hydrated dipalmitoylphosphatidylcholine (DPPC) and DPPC/water/ethanol phases have been studied by lowangle time-resolved x-ray diffraction under conditions similar to those employed in calorimetry (scan rates 0.05-0.5 degrees C/min and uniform temperature throughout the samples). This approach provides more adequate(More)
Heating and cooling phase sequences observed in phospholipid and glycolipid dispersions in excess water have been summarized. Differences between heating and cooling sequences and also with respect to a reference phase sequence "subgel-gel-lamellar liquid crystalline-cubic-inverted hexagonal" have been pointed out. Together with kinetic data obtained by(More)
Dihexadecylphosphatidylcholine (DHPC)/cholesterol binary mixtures in excess of water have been characterized by small-angle X-ray diffraction and differential scanning calorimetry and a temperature-composition phase diagram for this binary has been constructed. The property of cholesterol to perturb the hydrocarbon chain interdigitation in the lamellar gel(More)
Fully hydrated dipalmitoylphosphatidylcholine (DPPC) undergoes liquid crystalline to metastable P(beta), phase transition in cooling. A small angle x-ray scattering study has been performed for obtaining further evidence about the structure of this phase. From a high-resolution observation of x-ray diffraction profiles, a distinct multipeak pattern has(More)