1.2- Dioleoylphosphatidic acid

A modification of this method was described by Aurora et al. (1985). The LUV vesicles (300-600 nm) were prepared by dispersing dioleoylphosphatidic acid (DOPA) and cholesterol at a high salt concentration. The preparation formed contained only about 3% SUV vesicles. 

Compounds 19 and 20 along with some acylated phosphatidic derivatives in addition to 1,2-dioleoylphosphatidic acid, were tested using the particle bioassay [83]. Commercially available l-oleoyl-2-lysophosphatidic acid (21) possessed repellent activity which was enhanced by monomethylation. When A. cochlioides zoospores were pre-treated with an excess of the natural stimulant N-frans-feruloyltyramine (19), and then exposed to Chromosorb W AW particles coated with various test compounds, it was found that 1 -oleoyl-2-lysophosphatidic (21, 100 ppm) and its monomethyl ester (22) (10 ppm), as well as the natural repellent 1-linoleoyl-2-lysophosphatidic acid monomethyl ester (20, 30 ppm), effectively inhibited zoospore motility [83], However, l-oleoyl-2-lysophosphatidic acid dimethyl ester (23) and 1,2-dioleoylphosphatidic acid tested with and without the stimulant (19) showed neither repellent nor motility inhibitory activity. The bioassay revealed that compounds possessing repellent activity are monoacylated phosphatidic acid derivatives containing at least one hydroxy group on the phosphoryl unit [83]. 

Figure 1.5. Correlation between the total amount of protein adsorbed and circulation time before plasma clearance of large unilamellar vesicles (LUVs) containing trace amounts of [3H]cholesteryl-hexadecyl ether administered intravenously in CDl mice at a dose of about 20 pmol of total lipid per 100 g of mouse weight. Results are shown for liposomes containing SM PC ganglioside GMl (72 18 10) (open square), PC CH (55 45) (filled circle), PC CH plant PI (35 45 20) (filled square), SM PC (4 1) (open triangle), PC CH dioleoylphosphatidic acid (DOPA) (35 45 20) (open diamond), and PC CH DPG (35 45 20) (open circle) (SM, sfingomyelin PC, phosphatidyl choline CH, cholesterol PI, phosphatdylinositol DPG, diphosphatidyl glycerol) (data from ref. (55))...

Chloroform solutions of dioleoylphosphatidylcholine (DOPC), dioleoyl-phosphatidylethanolamine (DOPE), dioleoylphosphatidylserine (DOPS), dioleoylphosphatidic acid (DOPA), and phosphatidylinositol (PI) from soybean are purchased from Avanti Polar Lipids (Alabaster, AL). Phosphatidylinositol 4-phosphate (PI4P), phosphatidylinositol 4,5-biphosphate (PIP2), and cytidine 5 -diphosphate-diacylglycerol (CDP-DAG) are obtained from Sigma (St. Louis, MO). Cholesterol is purchased from Nacalai... 

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