Showing papers in "Chemistry and Physics of Lipids in 1983"

TL;DR: In this article, the authors introduce the concepts of order parameters and correlation functions needed for a description of orientational ordering in a liquid crystal or a membrane bilayer, and the theory of rotational depolarization of fluorescence for a probe in an ordered phase is introduced.

TL;DR: In this paper, the current status of the spin label technique as applied to model and biological membranes, with emphasis on structural and dynamic parameters that can be deduced from ESR and saturation transfer (ST) ESR spectra.

TL;DR: The results suggest that protein concentrations in surfactant mixtures can be minimized for applications such as exogenous lung Surfactant replacement for the neonatal Respiratory Distress Syndrome (RDS).

TL;DR: In this article, α-tocopherol has been used to extract isomeric monohydroperoxides of methyl arachidonate and 2-linoleoyl-1,3-dipalmitoylglycerol.

TL;DR: It was found that small amounts of polyunsaturated fatty acyl chains in a phosphatidylethanolamine disproportionally lower its bilayer to hexagonal transition temperature.

TL;DR: Evidence for enhanced stability of polymerized vesicles is given by treatment with ethanol and detergents showing that trapped markers are released to a much smaller extent than in the case of unpolymerized vESicles.

TL;DR: It is demonstrated that using these soft mass spectrometric ionization techniques, accurate, fast, and sensitive fatty acid profiling of phospholipids can be performed.

TL;DR: There are different mechanisms involved in the L alpha, HII, CII polymorphic transitions, and that different types of 'lipidic particles' representing different molecular organizations may be involved in each case.

TL;DR: The thermotropic behavior of the two synthetic CBSs were compared to each other and to the corresponding components in natural CBS, in order to determine the contribution of the hydroxy fatty acid to intermolecular hydrogen bonding between molecules of the lipid.

TL;DR: This value represents a discontinuity in the positional dependence of the molecular order parameter for the sn-2 chain of PDSPC, indicating that the cyclopropane ring provides a rigid barrier separating the lipid bilayer into two regions: an ordered region from the bilayer surface to the site of the cycling ring and a much more disordered region thereafter to the center of the bilayers.

TL;DR: Equilibrium dialysis experiments are used to measure excluded volumes for the non-electrolyte permeant erythritol in lipid bilayer systems and the finding that the permeant is excluded indicates that the water layers contribute to the permeability barrier.

TL;DR: The neutral alpha-tocopheroxyl radicals, generated in monolayers on silica gel containingalpha-tocopherol and partly autoxidised methyl linoleate at 90 degrees C, were detected and identified by ESR spectroscopy and lend support to the view that ascorbate transfers hydrogen to alpha-ptychopherol thus regenerating alpha-ocopherol.

TL;DR: In this paper, the effect of rotametric isomerism on the orientational disorder of lipid hydrocarbon segments and relate this to the thermodynamic state was considered, with special emphasis on methods sensitive to fluctuation properties.

TL;DR: It is concluded that the rigidifying effect of cholesterol in membranes does not depend on specific sites of interaction and that with respect to physical membrane properties phosphatidylcholine behaves as an achiral molecule.

TL;DR: The specific capacity of the mixed membranes was found to increase with increasing hopanoid content, indicating an interaction between hopanoids and lipids which leads to a reduction of the chemical potential of the solvent in the membranes.

TL;DR: In this paper, the synthesis and physical properties of a new anthracene fatty acid, 9-(2-anthryl)nonanoic acid, and the corresponding anthracenes-phosphatidylcholines which were obtained by condensing the acid with sn -1-palmitoyl-lysophosphatideyl-polymorphic choline (PAPC) and with EAPC, were described, showing that these lipids can undergo a liquid-crystal to gel phase transition at temperatures of 15°C and 18°

TL;DR: In this paper, a method for the chemical synthesis of 1-O-hexadecyl dihydroxyacetone-3-phosphate is described, which can be used to prepare different acyl and alkyl derivatives of dihydroxacetone phosphate in good yield.

TL;DR: The polymerized monolayers were more densely packed and more stable than their monomeric counterparts as indicated by the smaller areas and higher pressures reached before the collapse points.

TL;DR: A rotating quasi-rigid prism model has been used to establish a correlation between the molecular structure, conformation and surface properties of monolayers formed by the two saturated galactolipids as discussed by the authors.

TL;DR: The present fluorimetric assay easily detects hydrolysis of C30PHPC in the pmol min-1 range, indicating a close packing of the phospholipid pyrene moieties in the lipid phase and confirming the absolute requirement for Ca2+ of this enzyme.

TL;DR: In this paper, the difference in phase properties between the two isomers is discussed in relation to differences in the molecular geometry and is related to observations on variations in fat absorption related to positional isomers of triglycerides.

TL;DR: The results indicate that although the orientation and conformations of the membrane lipids in the region of the C-2 position of the chains are qualitatively very similar among the various lipid classes, quantitatively there are some differences, particularly between the glycolipids and the phospholipids.

TL;DR: Different chemical groups of single negatively charged phospholipids or of electrostatically neutral lipids have no significant effect on drug binding which proves that binding is not influenced by steric and bulky head group configurations.

TL;DR: In this article, the two principal hydrocarbon chain conformations (type α or liquid-like and type β or rigid-like) are described for lipid-water phases and several phases, predominantly lamellar, which have interdigitated hydrocarbon chains or in which the α and β conformations are periodically or randomly arranged.

TL;DR: This result argues for lipid-lipid complexing in the "hydrogen belts' of the lysoPC-cholesterol bilayer, specifically, for hydrogen bonding involving the hydroxyl and carbonyl groups of ly soPC and the hydoxyl of cholesterol.

TL;DR: A new thin-layer chromatographic method is developed to study the interaction of monovalent cations and phospholipids and indicates that phosphatidylcholine differentiates relatively better between the monovalENT cations than phosph atidylserine.

TL;DR: Analytically pure 1,2-dipalmitoyl-sn-glycero-3-phosphoric acid was prepared in gram amounts, using a simplified version of a previous procedure, and the interest of the method was illustrated by the synthesis of two dipalmitoysl phosphatidylcholines selectively deuterated on the polar headgroup.

TL;DR: In this paper, the phase transition behavior of solution-grown mono-domain thin layered crystals of Dipalmitoylglycerophosphocholines (dipalmitoysl-GPC) was investigated in a low hydration region at room temperature.

TL;DR: It is thought that sulfatide causes strong side-to-side head-group interactions on the bilayer surface, causing the lipid chains to assemble in a more rigid fashion, though this effect may be balanced in part by the disordered mechanical coupling of glycolipid acyl chains in the apposite faces of the hydrophobic core of the bilayers.

TL;DR: The binding of Eu 3+ to phospholipids was studied by pulsed, time-resolved fluorimetry (phosphorescence) and results in strong enhancement of light emission measured 0.4–0.9 ms after exciting flashes of 0.5 μs duration.