Oxidation of monoterpenes in Protium heptaphyllum oleoresins.

Protium heptaphyllum (Burseraceae) oleoresins are rich in volatile monoterpenes, exhibiting a chemical composition that can be strongly altered with time. The present work aimed to discuss the temporal change of the volatile composition of these oleoresins, and search for related supporting evidence. Samples of P.

Biphasic regulation of type II phosphatidylinositol-4 kinase by sphingosine: cross talk between glycero- and sphingolipids in the kidney.

Phosphatidylinositol-4 kinase (PI-4K) is responsible for the generation of phosphatidylinositol-4 phosphate (PtdIns(4)P), a bioactive signaling molecule involved in several biological functions. In this study, we show that sphingosine modulates the activity of the PI-4K isoform associated with the basolateral membranes (BLM) from kidney proximal tubules. Immunoblotting with an anti-α subunit PI-4K polyclonal antibody revealed the presence of two bands of 57 and 62kDa in the BLM.

Diacylglycerol kinase activity in purified basolateral membranes of kidney tubules. I. Evidence for coupling with phospholipase C.

The diacylglycerol kinase (DGK) catalyzes the phosphorylation of diacylglycerol (DAG) yielding phosphatidic acid (PA) signaling molecules which are involved in the modulation of different cell responses. The aim of this work was to characterize the DGK activity associated to the basolateral membranes (BLM) of kidney proximal tubules, in a native preparation that preserves the membrane microenvironment. The Arrhenius plot of DGK activity was non-linear, indicating a complex influence of the lipid environment of the native membrane.