Phospholipid composition

The arrows indicate the effect of increase in the corresponding parameter on fluidity. Depends on membrane phospholipid composition (headgroups negatively charged). 

Yasuda, T., Dancey, G.F., and Kinsky, S.C. (1977) Immunogenicity of liposomal model membranes in mice Dependence on phospholipid composition. Proc. Natl. Acad. Sci. USA 74, 1234-1236. 

Amselem, S., A.J. Domb, C.R. Alving, Lipospheres as Vaccine Carrier Systems Effects of Size, Charge, and Phospholipid Composition, Vaccine Research. 1, 383, 1992. 

An important question arises about the effects of phospholipid composition and the function of membrane-bound enzymes. The phospholipid composition and cholesterol content in cell membranes of cultured cells can be modified, either by supplementing the medium with specific lipids or by incubation with different types of liposomes. Direct effects of phospholipid structure have been observed on the activity of the Ca2+-ATPase (due to changes in the phosphorylation and nucleotide binding domains) [37]. Evidence of a relationship between lipid structure and membrane functions also comes from studies with the insulin receptor [38]. Lipid alteration had no influence on insulin binding, but modified the kinetics of receptor autophosphorylation. 

The region at the surface of membranes and the underlying phospholipid head-group region are of particular interest since these regions can vary considerably with variations in the membrane phospholipid composition and under the influence of external molecules such as ions and hydrophobic molecules. The fluorescence anisotropy parameter tends to be less useful for examining this region since it is already intrinsically disordered and the... 

The AmB/phospholipid ratio was varied between 2.5% and 50% (w/w) and, at a fixed AmB/phospholipid ratio, the phospholipid composition was varied from 100% DMPC to 100% DMPG. As a control, AmB was also precipitated alone, without lipid. 

The mean particle diameter was measured by photon correlation spectroscopy (PCS) with a Nanosizer N4 (Coultronics, Margency, France). The size and polydispersity of AmB lipid preparations depended on both the AmB/phospholipids ratio and the phospholipid composition. At a DMPC/DMPG molar ratio of 7/3, when the AmB content was below 10% w/w, large poly disperse particles were formed. At AmB ratios of 20% to 50% of total weight of phospholipids, a majority of submicronic particles were obtained. The smallest size, around 300 nm, and minimal polydispersity were achieved with AmB at 35% w/w that... 

Changes in phospholipid composition between tiie inner and outer leaflets are brought about by die activity of a membrane enzyme known as a phospholipid translocase (or... 

It is tempting to suggest that the binding of Ras and Raf to membranes may provide a link between diet and tumour development. There is evidence that a chronic alteration in the phospholipid composition of membranes, which can be... 

Amselem S., Domb A.J., and Alving C.R., Lipospheres as vaccine carrier systems effects of size, charge, and phospholipid composition. Vaccine Res., 1, 383, 1992. 

The plasma membrane, a phospholipid bilayer in which cholesterol and protein molecules are embedded. The bottom layer, which faces the cytoplasm, has a slightly different phospholipid composition from that of the top layer, which faces the external medium. While phospholipid molecules can readily exchange laterally within their own layer, random exchange across the bilayer is rare. Both globular and helical kinds of protein traverse the bilayer. Cholesterol molecules tend to keep the tails of the phospholipids relatively fixed and orderly in the regions closest to the hydrophilic heads the parts of the tails closer to the core of the membrane move about freely. This model is not believed to apply to blood or lymph capillaries. (Reprinted with permission from Bretscher MS. The molecules of the cell membrane. Sci Am 1985 253 104. Copyright 1985 by Scientific American, Inc. All rights reserved.)... 

Toxicity assessment. Ethanol extract of the leaf, administered intraperitoneally to mice, was active, LDjf, 0.75 g/kg"" " . Ethanol extract of the fresh leaf and stem, administered intraperitoneally to mice at the minimum toxic dose of 1 mL/animal, was active. Water extract of the fresh leaf and stem, administered intraperitoneally to mice at the minimum toxic dose of 1 mL/ animal, was active " . Aqueous extract of the husk fiber, administered orally to mice, was active, LDjf, 2.30 g/kgf" " . Tricarboxylate carrier influence. Oil, administered to rats at a dose of 15% of the diet for 3 weeks, produced a differential mitochondrial fatty acid composition and no appreciable change in phospholipids composition and cholesterol level. Compared with coconut oil-fed rats, the mitochondrial tricarboxylate carrier activity was markedly decreased in liver mitochondria from fish oil-fed rats. No difference in the Arrhenius plot between the two groups was observed "". 

Adversely affects phospholipid composition and synthesis in roots and microsomes from seedlings by inhibition of choline phosphotransferase (6)... 

Ellingson, J. S., Smith, M., Larson, L. R. Phospholipid composition and fatty acid profiles of the phospholipids of bovine predentin. Calc. Tiss. Res. 24, 127 (1977)... 

Although phospholipids are natural components of nearly all food products, the analysis of the phospholipid composition is of importance mainly in the certification and quality control of lecithins. According to the European Analytical Subgroup of the International Lecithin and Phospholipid Society (ILPS), there is an urgent need for a standard method for the determination of the PL composition, for this would allow a better characterization of lecithin and PL products (15,16). Besides, the nonavailability of good calibration standards is a major problem when comparing analytical results between companies. In order to try to solve the latter problem, the ILPS proposes a calibration standard whose composition is certified by 31P-NMR as an absolute tech-... 

R Przybylski, NAM Eskin. Phospholipid composition of canola oils during the early stages of processing as measured by TLC with flame ionization detector. J Am Oil Chem Soc 68 241-245, 1991. 

MA Murcia, J Villalain. Phospholipid composition of canned peas by P-NMR. J Sci Food Agric 61 345-347, 1993. 

RL Engen, CL Clark. High performance liquid chromatography determination of erythrocyte membrane phospholipid composition in several animal species. Am J Vet Res 51 577-580, 1990. 

Engelmann B., Streich S., SchonthierU. M., Richter W. O., and Duhm J. (1992). Changes of membrane phospholipid composition of human erythrocytes in hyperlipidemias. I. Increased phosphatidylcholine and reduced sphingomyelin in patients with elevated levels of triacylglycerol-rich lipoproteins. Biochim. Biophys. Acta Lipids Lipid Metab. 1165 32-37. 

Hunt A. N. and Postle A. D. (2006). Mass spectrometry determination of endonuclear phospholipid composition and dynamics. Methods 39 104-111. 

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