Impact of substrate material on algal biofilm biomass growth.

Algae are being grown for wastewater purification and biofuels production. Their growth on a substrate facilitates these uses by allowing facile separation of algae from the water. Here, we compare different materials to determine which would best serve this purpose.

A NOVEL ASSAY OF ACYL-COA:DIACYLGLYCEROL ACYLTRANSFERASE ACTIVITY UTILIZING FLUORESCENT SUBSTRATE(1).

Common methods for assaying acyl-CoA:diacylglycerol acyltransferase (DGAT) enzymatic activity rely upon radiolabeled substrates or product assay. We developed a novel assay that directly quantifies endogenous DGAT activity through the use of a fluorescently labeled substrate. We performed this assay with microsomal protein, 2-(6-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)hexanoyl-1-hexadecanoyl-sn-glycero-3-diacylglycerol (NBD-DAG), and oleoyl-CoA substrates.

Lipase and phospholipase inhibitors: design and applications.

Lipases are important drug discovery targets since they play central roles in signal transduction and metabolism. Many inhibitors have been isolated from natural sources and others derived through synthesis of substrate analogs or biomimetics. Because lipids are hydrophobic, there are special procedures needed for their study.

Phospholipase D modulation by ceramide in senescence.

Phospholipase D (PLD) has been implicated in mitotic regulation and has been shown to be defective in cells following replicative senescence. We examined the source of changes in PLD activity in senescent human umbilical vein endothelial cells and in human diploid fibroblasts. Using fractionated cell components we found that the cytosolic components were necessary for maximum PLD activation.

Ceramide induces endothelial cell senescence.

Ceramide has been proposed to be a mediator of replicative senescence. Our aim was to determine whether ceramide induces senescence in vascular endothelial cells. Human umbilical vein endothelial cells were cultured to different population doubling levels and ceramide levels were quantitated.

Shift in sphingolipid metabolism leads to an accumulation of ceramide in senescence.

Ceramide mediates the effects of several agonists leading to differentiation, apoptosis or senescence. We previously showed that ceramide becomes elevated in senescent fibroblasts. In the present study, senescent cultures of Wi-38 fibroblasts and human umbilical-vein endothelial cells were compared to low-passage cultures in order to identify which of the several pathways is predominantly responsible for the increased ceramide.