Phosphatidylcholine, extraction from

SLPC l-stearoyl-2-lauril-5n-glycero-3-phosphatidylcholine SOPC l-stearoyl-2-oleoyl-5 -glycero-3-phosphatidylcholine soybeanPC phosphatidylcholine extracted from soybean T T transcription and translation... 

Winther, B., Hoem, N., Berge, K., and Reubsaet, L. (2011). Elucidation of phosphatidylcholine composition in krill oil extracted from Euphausia superba. Lipids 46,25-36. 

In initial work, L- a-phosphatidylcholine (lecithin) from egg yolk was selected as the phospholipid, and later studies compared other phospholipids and lipid extracts from meat. As the study originated from investigations of cooked meat flavor, the model system reactions were carried out in aqueous solution buffered with phosphate at an initial pH of 5.7 and concentrations of the reactants were selected to approximate their relative compositions in mammalian muscle. The reactions were carried out under pressure... 

The observations on the aromas from cysteine + ribose reaction mixtures have been extended to compare the effect of different lipids triglycerides and phospholipids extracted from beef, and commercial egg lecithin (phosphatidylcholine) and egg cephalin (phosphatidylethanolamine) (L.J. Salter D.S Mottram, unpublished data). The inclusion of the beef triglycerides (TG) did not appear to have any effect on the aroma of the cysteine + ribose reaction mixture, which was sulfurous with an underlying meatiness. However, when beef phospholipids (FL) were used the meaty aroma increased markedly. Similarily, addition of egg lecithin (LEC) or egg cephalin (CEPH) to the cysteine + ribose reaction mixture gave increased meatiness, with the cephalin-containing mixture being judged to have the most meaty character. 

Improvement of membrane separation technology has resulted in the isolation of MFGM-enriched material from commercially available products. A phospholipid-rich fraction can be extracted from whey (Boyd et al., 1999) and buttermilk (Sachedva and Buchheim, 1997) with a reported yield of 0.25 g of phospholipids/g of protein in buttermilk (Sachdeva and Buchheim, 1997). Microfiltration of whey derived from the Cheddar cheese process, using 0.2 pm ceramic filters results in a fraction containing two major phospholipids, phosphatidylcholine and phosphatidylethanolamine, and lesser amounts of phosphatidylinositol, phosphatidylserine, sphingomyelin and cerebrosides (Boyd et al., 1999). The phospholipid fraction separated from the total lipids contains a larger proportion of mono- and polyunsaturated fatty acids (mainly oleic, Cig i and linoleic, C ) compared to the total lipid and the neutral lipid fraction (Boyd et al., 1999). 

Phospholipids (Figure 3) are constituents of membranes and are only minor components of oils and fats, sometimes responsible for cloudiness. They are usually removed during degumming, the residue from soybean oil processing being a source of phospholipids used as food emulsifiers. The term lecithin is used very loosely for such material, and it may variously mean phosphatidylcholine, mixed glycerophospholipids, or cmde phospholipid extracts from various sources. Where possible, more specific nomenclature or the source and purity should be used (14). 

Supercritical CO2 extraction also has been used to selectively extract phosphatidylcholine from de-oiled soybean lecithin (197). The effects of temperature, pressure, and amount of ethanol on phosphatidylcholine extraction were examined, and a high-purity product could be produced with optimized conditions. 

Membrane-filter immobilized-permeability-botanical The assessment of transport properties of 23 drugs and natural product molecules was made by using the in vitro model based on filter-IAM, assembled from phosphatidylcholine in dodecane, in buffer solutions at pH 7.4. Five of the compounds were lactones extracted from the roots of the kava-kava plant. Experiments were designed to test the effects of stirring (0-600 rpm) during assays and the effects of varying the assay times (2-15 hr). 

Fig. 6 Plot of membrane tension t as a function of dilation for a wide range of copolymer amphiphiles as extracted from MD simulations. The computational models, derived from systematic coarse-graining (black symbols), show nearly the same dilational behavior marked by the solid line. The slope of the line, ka, is very close to experimental measurements performed on giant vesicles 0colored symbols). Experimental data for a dimyristoyl phosphatidylcholine lipid membrane are also shown. The point of membrane lysis as observed experimentally for selected lipid and polymersome systems is also shown in the plot with green and red stars, respectively. Reprinted by permission from Macmillan Publishers Ltd Nature Materials, Ref. [85], copyright (2004)...

Fig. 21.6 Typical positive ion MALDI-TOF mass spectra of organic extracts of spermatozoa from a healthy volunteer. Before MS analysis, spermatozoa were separated into annexin V-negative (a) and annexin V-positive (b) spermatozoa. Peaks are labeled according to the corresponding m/z ratios. The most indicative peak groups are marked with grey bars. The asterisk indicates a typical DHB matrix peak (m/z = 551). Abbreviations LPC, lyso-phos-phatidylcholine PC, phosphatidylcholine. Reprinted from Glander et al.. Deterioration of spermatozoal plasma membrane is associated with an increase of sperm lyso-phosphatidyl-cholines, Andrologia, 2002 with permission from Blackwell...

Experiment I. In a time-course experiment, mucosal PGE production and phospholipid fatty acid profile were assessed at d 0,4,8,12, and 16 of dietary treatment in formula-fed and naturally reared piglets (n = 5 piglets per time per dietary treatment). Mucosal cells were scraped from proximal ends of the small intestine and frozen at -80°C for later lipid analysis. Lipids were extracted by a modified Folch procedure (15). Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) were separated by thin-layer chromatography (16), and fatty acids in each phospholipid fraction were analyzed by gas chromatography. For eicosanoid measures, fresh mucosal tissue was incubated in Kreb s Ringer bicarbonate buffer as described previously (17). PGE2 was extracted from the incubation media with ethyl acetate and quantified using a competitive enzyme-linked immunosorbent assay (Cayman Chemical, Ann Arbor, MI). 

The second example represents a large-scale human metabolomics study that was performed with LC/MS [54]. The aim of this study was to identify potential biomarkers from lipid profiles of some 600 human plasma samples. Lipids were extracted from plasma samples and subjected to LC/ESI-MS analysis. Several different classes of lipids, such as phosphatidylcholines, lysophosphatidyl-cholines, triglycerides, diglycerides, sphingomyelins, and cholesterol esters were the target of this study. To detect small differences in metabolic profiles, statistical methods were used to process this large set of data. Partial least-squares discriminant analysis of the data could locate potential biomarkers. 

To understand the mechanism of phospholipid exchange, it is worthwhile to consider the properties of the purified phosphatidylcholine-PLEP extracted from beef liver (Colley et al., 1973). The protein, which has no distinct pH optimum, has an isoelectric point of 5.8. It consists of 190 amino acids, of which 38% contain charged residues and 38% contain nonpolar side chains a disulfide bridge is present, and the N-terminal amino acid is glutamic acid. Lipid analyses on non-lyophilized protein have demonstrated that the protein contains one equivalent of phosphatidylcholine per mole of protein. 

Phospholipids were extracted from erythrocyte membranes and were analyzed along with their lipoxygenase peroxide products using a 40°C aminopropyl column. Phospholipids (phosphatidylcholine [PC], phosphatidylethanolamine [PE], phospha-tidylinositol, phosphatidylserine [PS], and sphingomyelin) were separated using a 67/22/11 acetonitrile/methanol/water (0.2% TFA) mobile phase (A = 2I0nm). Elution was complete in 30 min and excellent resolution was achieved. The peroxide forms of PC, PE, and PS were separated at the same time but monitored at k — 234 nm. All samples were stabilized with 20mg/L BHT solutions [1185]. 

Figure 2. Thin layer chromatogram of total lipids extracted from microsomal membranes (lane 1) and cytosolic lipid-protein particles (lane 2) isolated from cotyledon tissue of Phaseolus vulgaris. PC, phosphatidylcholine PE, phosphatidylethanolamine PG, phosphatidylglycerol PI, phsophatylinositol FFA, free fatty acids TAG, triacylglycerol SE/WE, steryl and wax esters.

Figure 4. Analysis of the different polyphosphoinositides extracted from P-labelled cells. (A) Schematic representation of the expected separation of a mixture of P-labelled phospholipids by thin layer chromatography (TLC). Plates are silica gel 60 and the solvent for phosphoinositide separation is a mixture of CHCI3, CH3COCH3, CH3OH, CH3COOH and H O (80 30 26 24 14, v/v). MP, major phospholipids (phosphatidylserine, phosphatidylcholine and phosphatidylethanolamine). (B) Typical high-performance liquid chromatography profile showing the separation of the various phosphoinositides from a mixture of P-labelled phosphoinositides. A specific gradient must be used to separate PtdIns(4)P and PtdIns(5)P (Rameh et ai, 1997 Niebhur et al., 2002).

There are two ways in which membranes of diacetylenic lipids containing intrinsic membrane proteins can be obtained either proteins extracted from natural membranes with detergent can be reconstituted into synthetic diacetylenic phosphatidylcholines or the growth medium of micro-organisms incapable of synthesizing their own fatty acids can be enriched with diacetylenic fatty acid. In this laboratory, Ca2+-ATPase from sarcoplasmic reticulum and bacteriorhodopsin from the purple membrane of Halobacterium halobium have been reconstituted into diacetylenic phosphatidylcholines. Provided the more reactive mixed-chain lipids are used polymerisation can be achieved before the protein is denatured by the UV irradiation. Both proteins remain active within polymeric bilayers. 

Figure 4.9 Representative ESI-MS analysis of lipid classes resolved by intrasource separation. Lipid extracts from mouse liver samples were prepared by using a modified procedure of Bligh and Dyer [1]. MS analysis was performed with a TSQ Vantage triple-quadrupole mass spectrometer (Thermo Fisher Scientific, San Jose, CA) equipped with an automated nanospray apparatus (i.e., TriVersa, Advion Bioscience Ltd., Ithaca, NY) and Xcalibur system software. Mass spectra were acqnired directly from the diluted hpid extract in the negative-ion mode (a), after addition of 50 nmol LiOH/mg of protein in the diluted lipid extract and analyzed in the negative-ion mode (h), or the identical hpid solution to that in (b) in the positive-ion mode (c). IS denotes internal standard PC, PE, PG, PI, PS, TAG, NEFA, and CL stand for phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidyUnositoL phosphatidylserine, triacylglycerol, nonesterified fatty acid, and doubly charged cardioUpin, respectively.

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