Egg yolk phosphatidylcholine

DGDG digalactosyl diacylglycerol DHPC dihexadecyl phosphatidylcholine DMPC dimyristoyl phosphatidylcholine DOPC dioleoyl phosphatidylcholine DPPC dipalmitoyl phosphatidylcholine EYPC egg yolk phosphatidylcholine POPC 1-palmitoyl 2-oleoyl-phosphatidylcholine SBPC soya bean phosphatidylcholine... 

Lamellar phases of phospholipids often exhibit myehnic figures when contacted with water. Electron micrographs [24,26] showed that each tubular myehnic figure in the egg-yolk phosphatidylcholine/water system consisted of a water core surrounded by many concentric bilayers. More recently Raman spectroscopy techniques have confirmed the concentric bilayer arrangement [1,18]. Myelinic figures are not equilibrium structures, however, and eventually break up to form vesicles or other lamellar structures. Indeed, adding water to a vessel whose inner walls are coated with a thin layer of a lamellar phase of low water content is a well-known way of forming vesicles. 

Single-compartment egg yolk phosphatidylcholine vesicles Au Nanosized Au particles precipitated in the vesicles 78... 

Egg yolk phosphatidylcholine. [7-3H(N)]-cholesterol. ApoA-I. NaCl. Ethanol. 

For -LCAT activity the apoA-I proteoliposome emulsion is prepared by evaporating 260 pi of 5 mg/ml egg yolk phosphatidylcholine, 150 pi of 1 mg/ml unesteri-fied cholesterol, and 3 pi of 21 Ci/mmol [7-3H(N)]-cholesterol. The dried lipids are dissolved in 125 pi pure ethanol and injected into 10 ml of analysis buffer and vor-texed. The emulsion is concentrated by ultrafiltration to less than 2.5 ml and then filled up to 2.5 ml. A 300-pL aliquot of this emulsion is incubated with 75-150 mg of apoA-I and 1.1 ml analysis buffer. The optimal amount of apoA-I varies from lot to lot and has to be optimized using normal plasma samples. 

Egg yolk phosphatidylcholine. Cholesterol. Cholesteryl oleate. [3H]-cholesteryl oleate. Chloroform. Ethanol. Sodium phosphate. EDTA. NaN3. Sodium cholate. NaCl. 

To prepare proteoliposomes, 7 mg egg yolk phosphatidylcholine, 1.16 pg cholesterol, 77.5 pg cholesteryl oleate and 10 pCi [3H]-cholesteryl oleate, all dissolved in chloroform are mixed. After evaporation of chloroform with nitrogen, the lipids are resolved in 400 pi ethanol. The ethanolic solution is injected into 5 ml of a vortex-ing buffer with 39mmol/l sodium phosphate, 0.01% EDTA, 2 mmol/1 NaN3, and 12 mmol/1 sodium cholate (pH 7.4) 3 mg apoA-I is added. The solution is subsequently dialyzed against a buffer with 39 mmol/1 sodium phosphate, 0.01 % EDTA, 2 mmol/1 NaN3, and 12 mmol/1 sodium cholate (pH 7.4) at 4°C. At the end the solution is filled up with analysis buffer containing 39 mmol/1 sodium phosphate,... 

With different methods one can recognize different hydrates of phospholipids with different properties. Solved in different organic solvents like benzene, xylene etc. egg yolk phosphatidylcholine adsorbed water in an amount of 13.6 water/mol lipid, independently of the used organic solvent165. Studying adsorption isotherms of water vapor on lipids Elworthy166 has found saturation values at 25 °C ... 

Other types of inverse micelles, such as those of egg yolk phosphatidylcholine (87) and a calcium alkylarylsulfonate (88) have also been investigated. As recently discussed (88), the properties of inverse micelles formed by different surfactant molecules should be expected to be quite diverse. As an example, the interaction of a solubilizate (TbCl3) with surfactant headgroups of the calcium sulfonate surfactant mentioned above was found by FT-IR and energy transfer methods to be dramatically slower (10-150 hr) than that found with AOT (milliseconds). 

Moschetta, A., van Berge-Henegouwen, G.P., Portincasa, P., Palasciano, G., Groen, A.K., van Erpecum, K.J. 2000. Sphingomyelin exhibits greatly enhanced protection compared with egg yolk phosphatidylcholine against detergent bile salts. J. Lipid Res. 41, 916-924. 

This method is based on the affinity of the new chemical entity to a membrane, consisting of human serum albumin immobilized on Transil beads. The silica beads are coated with egg yolk phosphatidylcholine and are commercially available under the trademark Transil from Nimbus (Nimbus Leipzig Germany). 

Fig. 40. Fluorescence decay curves recorded at different emission wavelengths for TNS bound to liposomes of egg yolk phosphatidylcholine at 20 C...

A simple method to measure the membrane permeability to specific molecules has been presented by G. Battaglia and coworkers [141], The authors encapsulated highly hydrophilic 3,3, 3//-phosphinidynetris-benzenesulfonic acid (PH) into polyethylene oxidc)-co-poly(butylene oxide) (EB) vesicles and monitored its reaction with 5,5/-dithiobis-2-nitrobenzoic acid (DTNB) penetrating the membrane from the exterior. The reaction rate (amount of the formed product as a function of time after DTNB addition) measured with IJV/Vis was directly correlated to the permeability of the permeating molecule. A comparison of these results with the permeability of egg yolk phosphatidylcholine (PC) vesicles showed that EB membranes have a more selective permeability toward polar molecules than the phospholipids membranes. Also in this case the permeability appeared to depend on the membrane thickness as predicted by Fick s first law. 

Nonlabeled egg yolk phosphatidylcholine vesicles were applied to the DEAE column immediately before the separation step to preequilibrate the column with lipid. The recovery of acceptor vesicles was increased to 80-95%. 

Electron Microscope Studies. Electron microscope studies of phospholipids have been made by many investigators, but in general the material used has been natural phospholipid and particularly egg yolk phosphatidylcholine. Recently we have studied some pure phosphatidyletha-nolamines (8). Fully saturated phospholipids are crystalline at room temperature and show no interaction with the material commonly used for staining purposes—i.e., osmium tetroxide. If these phospholipids are... 

Model phospholipid membranes of bilayer dimensions have been made with egg yolk phosphatidylcholine, but the formation of membranes becomes impossible as the temperature of preparation is lowered from 36° to 20°C. (H). This is probably related to the degree of fluidity of the hydrocarbon chains of the lipid at the temperature of the experiment, and the DTA results on egg yolk phosphatidylcholine are of interest in this respect. 

Figure 15. Plot of 1/7 jn vs approximate fatty acyl chain position for egg yolk phosphatidylcholine dispersions labelled within the C5 and spin labels. The l/ term is due to the relaxation mechanism in the presence of the unpaired electron of the nitroxide (taken from Godici and Landsberger, 1974).

Fatty Acids in 1 -position Fatty Acids in 2-position Egg Yolk Phosphatidylcholine Milk Serum Pig Liver Chicken Muscle Egg Yolk Phosphatidyl ethanolamine... 

Figure 9.25 Polymorphic phases available to hydrated liquid-crystalline phospholipids and the corresponding P-NMR spectra. The bilayer spectrum was obtained from aqueous dispersions of egg-yolk phosphatidylcholine the hexagonal spectrum corresponds to soybean phosphatidyl-ethanolamine the isotropic motion spectrum was obtained from a mixture 15 mol% egg-yolk phosphatidylcholine. The spectra were obtained at 30 °C in the presence of broad-band proton decoupling (from Cullis and deKruijff, 1979).

Figure 10.10. Relative antioxidant aetivities of epicatechin gallate (ECG), epicatechin (EC), quercetin (Q), and a-tocopherol (a-T) on the oxidation of egg yolk phosphatidylcholine liposome in the presence of a water-soluble initiator (AAPH) and in hexane-isopropanol solution in the presence of a lipid-soluble initiator (AMVN). From Terao et al (1994). FLAV, flavonoids.

Phospholipids purchase dioleoyl phosphatidylcholine (DOPC) or egg-yolk phosphatidylcholine (egg PC) (see Note 5)... 

Dioleoylphosphatidylcholine or egg-yolk phosphatidylcholine are used because their phase transition temperatures are low and they maintain a liquid-crystalline state at physiological temperatures. The former lipid is better defined chemically and the affinity of vesicles made from it for retinoids is very consistent between different preparations. The latter lipid is, however, less costly. Lipids can be purchased from Avanti Polar Lipids (Alabaster, AL)... 

In 1981, Helfrich [7] studied the effect of the external osmotic pressure on egg yolk phosphatidylcholine (EPC) giant vesicles by adding 15 mM of salt or glucose in the external medium of the vesicles. The vesicle radius appears to decrease linearly with time according to the law d /dt = -aPAc, where P is the membrane permeability coefficient to water, a, is the water molar volume, and Ac, the difference of molar concentrations. The water permeability coefficient for EPC bilayers was found to be 41 pms . ... 

The platinum wires of the preparation cell [5] were connected on the stage of the light microscope with the function generator, 1 ml of an aqueous solution was added, and the electric field was switched on (2 Vat 10Hz for POPC, and 3 Vat 15Hz for egg yolk phosphatidylcholine). 

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