The effect of phorbol esters on the light-evoked responses of horizontal cells were studied in the turtle eyecup preparation. Phorbol esters caused a reduction in receptive field size and a significant decrease in the amplitude of responses to annular and full-field illumination; however, they caused only minor changes in responses to small spots in the receptive field centre. The dark membrane...

Previous work has shown that cholesterol esters are relatively insoluble (<5 mol%) in bilayer phosphatidylcholine and sphingomyelin systems, but exhibit greater solubility in hexagonal (HII) phase anhydrous phosphatidylcholine systems obtained above 100°C. We examine here the influence of cholesterol esters of varying unsaturation on fully hydrated egg phosphatidylethanolamine systems, which un...

Wax esters are major constituents of the surface lipids in many terrestrial arthropods, but their study is complicated by their diversity. We developed a procedure for quantifying isomers in mixtures of straight-chain saturated and unsaturated wax esters having the same molecular weights, using single-ion monitoring of the total ion current data from gas chromatography-mass spectrometry. We exa...

The effect of lipid transfer proteins on the exchange and transfer of cholesteryl esters from rat plasma HDL2 to human very low (VLDL) and low density (LDL) lipoprotein populations was studied. The use of a combination of radiochemical and chemical methods allowed separate assessment of [3H]cholesteryl ester exchange and of cholesteryl ester transfer. VLDL-I was the preferred acceptor for trans...

The diacylglycerol signaling pathway, involving protein kinase C (PKC) and RasGRP, is a promising therapeutic target for both cancer and other indications. The phorbol esters, ultrapotent diacylglycerol analogues, bind to and activate PKC and RasGRP. Here, using fluorescent phorbol esters and complementary fluorescent PKC and RasGRP constructs, we determined the localization of the phorbol este...

The formation of N-methylpyridinium salts in the solvothermal synthesis of molybdenum(V) complexes with oxalate in methanol in the presence of pyridine was investigated. It was found that dimethyl oxalate is formed first, which can thereupon alkylate pyridine. Pyridine reacts with a variety of esters, forming N-alkylpyridinium salts. Most reactive in this respect are sulfonates, whereas among c...

Reported is a study evaluating the potential of esterified tannins as plastic additives in poly(lactic acid) (PLA). Tannin esterification using anhydrides was investigated as a route to synthesize tannin esters possessing varying ester chain length and degree of substitution (DS). Esterification decreased the tannin UV absorbance, predominately in the UVB region. However, tannin materials with ...

Volatile esters contribute important floral and fruity sensory properties to wine. Numerous factors influence the biosynthesis and hydrolysis of esters throughout yeast fermentation; however, methods to monitor the dynamic changes in ester production that occur during winemaking processes are limited. In this study, we showed that solid phase microextraction (SPME), a rapid, solventless samplin...