Phosphatidic acid-cholesterol

Fig. 23 Saliva and serum IgA (primary and secondary) response following orally administered soluble antigen Streptococcus mutans cell wall extract (open circles, soluble antigen solid circles, liposome-encapsulated material) (phosphatidylcholine, phosphatidic acid, cholesterol). (From Ref. 277).

Liposomes are multilamellar structures consisting of several bilayers of lipids (several pm) - they are produced by simply shaking an aqueous solution of phospholipids, e.g. egg lecithin. When sonicated, these multilayer structures produce unilamellar structures (with size range of 25-5 nm) that are referred to as liposomes. A schematic picture of liposomes and vesicles is given in Fig. 1.40. Glycerol-containing phospholipids are used for the preparation of liposomes and vesicles phosphatidylcholine phosphat-idylserine phosphatidylethanolamine phosphatidylanisitol phosphatidylglycerol phosphatidic acid cholesterol. In most preparations, a mixture of lipids are used to obtain the most optimum structure. 

FIGURE 12.4 (A) Diagrammatic representation of the separation of major simple lipid classes on silica gel TLC — solvent system hexane diethylether formic acid (80 20 2) (CE = cholesteryl esters, WE = wax esters, HC = hydrocarbon, EEA = free fatty acids, TG = triacylglycerol, CHO = cholesterol, DG = diacylglycerol, PL = phospholipids and other complex lipids). (B) Diagrammatic representation of the separation of major phospholipids on silica gel TLC — solvent sytem chloroform methanol water (70 30 3) (PA = phosphatidic acid, PE = phosphatidylethanolamine, PS = phosphatidylserine, PC = phosphatidylcholine, SPM = sphingomyelin, LPC = Lysophosphatidylcholine). 

PC = phosphatidylcholine, PE = phosphatidylethanolamine, PS = phosphatidylserine, PI = phosphati-dylinositol, Sph = sphingomyelin, FA = fatty acid, PA = phosphatidic acid, LPI = lyso-PI, CL = car-diolipin, LPC = Iyso-PC, CHO = cholesterol, CE = cholesterol ester, TG = triglycerides. 

The lipid component consists primarily of phospholipids and cholesterol. The most important group of phospholipids are phosphoglycerides, based on phosphatidic acid (where X = H), with the formula... 

Acetyl coenzyme A is the precursor of both cholesterol and fatty acids 39 Phosphatidic acid is the precursor of all glycerolipids 42 Sphingolipids are biosynthesized by adding head groups to the ceramide moiety 44... 

Cholesterol 1.2-Diacylglycerol Phosphatidylcholine dilinoleoyl Sulfatlde Phosphatidyl-L-aerine LysO pho phatldylglycerol Phosphalidylglycerol Phosphatidic acid Cardiollpid (E coli) CardioUpid (bovine) Nona... 

Monolayers of dicetyl phosphate-cholesterol follow the additivity rule for average area per molecule, whereas lecithin—cholesterol mono-layers deviate from it. The reverse is true for the additivity rule of average potential per molecule. Thus, the surface potential indicates that there is no interaction (or complex formation) between lecithin and cholesterol, but there is ion-dipole interaction between dicetyl phosphate and cholesterol as well as between phosphatidic acid and cholesterol. 

CH, cholesterol DLPC, dilaurylphosphatidylcholine DMPC, dimyristoyl-phosphatidylcholine DMPG, dimyristoylphosphatidylglycerol DPPC, dipal-mitoylphosphatidylcholine DPPG, dipalmitoylphosphatidylglycerol, DSPC, distearoylphosphatidylcholine DSPG, distearoylphosphatidylglycerol MLV, multilameller vesicle PA, phosphatidic acid PC, phosphatidylcholine TA, triamcinolone acetonide. 

Human carotids Atherosclerosis 4 patients TOF-SIMS Distribution of fatty acids, cholesterol, vitamin. E, phosphatidic acids, phosphatidylinositols, and triglycerides (34)... 

Cochleates can also be used for plasmid delivery. A negatively charged phospholipid such as phosphatidylserine, phosphatidic acid or phosphatidyl glycerol, in the absence or presence of cholesterol, are utilized to produce a suspension of multilamellar vesicles containing plasmids, which are then converted to small unilamellar vesicles by sonication. These vesicles are dialyzed against buffered divalent cations (e.g. calcium chloride) to produce an insoluble precipitate referred to as cochleates. Cochleates have been shown to encapsulate plasmid and enhance plasmid stability and transfection efficiency. 

Bodin S, Giuriato S, Ragab J, Humbel BM, Viala C, Vieu C, Chap H, Payrastre B. Production of phosphatidylinositol 3,4,5-trisphosphate and phosphatidic acid in platelet rafts evidence for a critical role of cholesterol-enriched domains in human platelet activation. Biochemistry 2001 40 15290-15299. 

NCEP National Cholesterol Education Program NHANES National Health and Nutrition Examination Survey NNT Number needed to treat PAP Phosphatidic acid phosphatase... 

Both lipids and polypeptides are implicated in host cell invasion by the related parasite Toxoplasma gondii (for review, see refs. 17,18). The rhoptry lipid composition of T. gondii is unusual (19). The cholesterol (Cho) to PhL ratio is high (1.48), and phosphatidylcholine (PC) accounted for greater than 75% of the rhoptry total lipids (TL). The remaining identifiable species were PE, phosphatidic acid (PA)... 

Liposomes from lecithin, cholesterol+ phosphatidic acid [24] Olive oil 3.6 0.4... 

---