Search results for "Phospholipase"
showing 10 items of 221 documents
Effect of Light on the Composition of Mitochondrial Lipids from Hypocotyl Hooks of Bean Seedlings (Phaseolus vulgaris L.).
1981
Summary Mitochondria were isolated and roughly purified from bean seedlings (phaseolus vulgaris) treated with different red light (660 nm) irradiation programmes. Etiolated seedlings were irradiated for short terms or grown in red light. The mitochondria from differently treated seedlings were analysed for their phospholipid and fatty acid patterns. The mitochondrial phospholipid patterns from green and etiolated seedlings were rather similar. This was also valid for the fatty acids from the phospholipid fraction whereas the fatty acid patterns of the glycolipids showed differences. Remarkable changes were observed in the phospholipid pattern of the mitochondrial fraction after short-term i…
Modulation of neuronal phospholipase D activity under depolarizing conditions
1999
Neuronal phospholipase D (PLD) activity was hypothesized to be involved in vesicle trafficking and endocytosis and, possibly, transmitter release. We here report that prolonged depolarization of rat hippocampal slices by potassium chloride (KCl) or 4-aminopyridine inhibited PLD activity. Similarly, PLD activity in rat cortical synaptosomes was significantly inhibited by depolarizing agents including veratridine and ouabain. Inhibition of calcium/calmodulin kinase II (CaMKII) which positively modulates synaptosomal PLD activity [Sarri et al. (1998) FEBS Lett. 440, 287-290] by KN-62 caused a further reduction of PLD activity in depolarized synaptosomes. Depolarization-induced inhibition of PL…
The role of lipid metabolism in the acquisition of desiccation tolerance inCraterostigma plantagineum: a comparative approach
2013
Summary Dehydration leads to different physiological and biochemical responses in plants. We analysed the lipid composition and the expression of genes involved in lipid biosynthesis in the desiccation-tolerant plant Craterostigma plantagineum. A comparative approach was carried out with Lindernia brevidens (desiccation tolerant) and two desiccation-sensitive species, Lindernia subracemosa and Arabidopsis thaliana. In C. plantagineum the total lipid content remained constant while the lipid composition underwent major changes during desiccation. The most prominent change was the removal of monogalactosyldiacylglycerol (MGDG) from the thylakoids. Analysis of molecular species composition rev…
Adrenergic modulation of astroglial phospholipase D activity and cell proliferation.
1999
As phospholipase D (PLD) activation has been associated with mitogenic signalling in several cell types, we tested an association between adrenergic activation of PLD and cellular proliferation in primary cultures of rat cortical astrocytes. In 2-week old cultures, PLD activation by noradrenaline (EC50: 0.49 microM) was inhibited by prazosin, a specific antagonist at alpha1-adrenergic receptors (IC50: 0.23 microM). Adrenergic PLD activation was not affected by genistein, an inhibitor of tyrosine kinases, or by Ro 31-8220, an inhibitor of protein kinase C (PKC), but was dose-dependently depressed in the presence of brefeldin A (1-100 microg/ml), an inhibitor of ARF activation. In experiments…
Enhancement of brain choline levels by nicotinamide: mechanism of action
1998
Following the subcutaneous (s.c.) administration of nicotinamide (10 mmol/kg), the brain and CSF levels of nicotinamide were increased to millimolar concentrations, but the concentrations of N-methylnicotinamide (NMN) in the CSF, and of NMN and NAD+ in brain tissue were not significantly altered. Concomitantly, nicotinamide caused increases of the choline levels in the venous brain blood. In hippocampal slices, nicotinamide (1-10 mM) induced choline release in a calcium- and mepacrine-sensitive manner and, in [3H]choline-labelled slices, increased the levels of [3H]lyso-phosphatidylcholine and [3H]glycerophosphocholine. We conclude that nicotinamide enhances brain choline concentrations by …
Engineered microenvironments for synergistic VEGF - Integrin signalling during vascularization
2017
We have engineered polymer-based microenvironments that promote vasculogenesis both in vitro and in vivo through synergistic integrin-growth factor receptor signalling. Poly(ethyl acrylate) (PEA) triggers spontaneous organization of fibronectin (FN) into nanonetworks which provide availability of critical binding domains. Importantly, the growth factor binding (FNIII12-14) and integrin binding (FNIII9-10) regions are simultaneously available on FN fibrils assembled on PEA. This material platform promotes synergistic integrin/VEGF signalling which is highly effective for vascularization events in vitro with low concentrations of VEGF. VEGF specifically binds to FN fibrils on PEA compared to …
Ontogenetic and Pharmacological Studies on Metabotropic Glutamate Receptors Coupled to Phospholipase D Activation
1997
The present study was aimed at characterizing the metabotropic receptor subtype which is involved in the activation of phospholipase D (PLD) by glutamate in rat hippocampal slices. We first observed that the ontogenetic profile of glutamate-induced hydrolysis of phosphoinositides and of phosphatidylcholine was strikingly similar. Both pathways were significantly activated by glutamate in tissue taken from 3-, 8- and 15-day old rats, but not in adult rats. PLD activation was strongest in slices taken from 8-day old rats. At this age, quisqualate had a higher potency for PLD activation (EC50: 0.6 microM) than 1S,3R-ACPD (EC50: 16 microM) and DHPG, a specific activator of group I mGluR, was a …
Palmitoylethanolamide Promotes a Proresolving Macrophage Phenotype and Attenuates Atherosclerotic Plaque Formation
2018
Objective— Palmitoylethanolamide is an endogenous fatty acid mediator that is synthetized from membrane phospholipids by N -acyl phosphatidylethanolamine phospholipase D. Its biological actions are primarily mediated by PPAR-α (peroxisome proliferator-activated receptors α) and the orphan receptor GPR55. Palmitoylethanolamide exerts potent anti-inflammatory actions but its physiological role and promise as a therapeutic agent in chronic arterial inflammation, such as atherosclerosis remain unexplored. Approach and Results— First, the polarization of mouse primary macrophages towards a proinflammatory phenotype was found to reduce N -acyl phosphatidylethanolamine phospholipase D expression …
Type-IIA secreted phospholipase A2 is an endogenous antibiotic-like protein of the host.
2010
International audience; Type-IIA secreted phospholipase A(2) (sPLA(2)-IIA) has been proposed to play a role in the development of inflammatory diseases. It has been shown to release arachidonic acid, the precursor of proinflammatory eicosanoids, to hydrolyze phospholipids of pulmonary surfactant, and to bind to specific receptors located on cell surface membranes. However, the most established biological role of sPLA(2)-IIA is related to its potent bactericidal property in particular toward Gram-positive bacteria. This enzyme is present in animal and human biological fluids at concentrations sufficient to kill bacteria. Human recombinant sPLA(2)-IIA is able to kill Gram-positive bacteria at…
Cross-talk between phosphatidic acid and ceramide during ethanol-induced apoptosis in astrocytes
2005
Background Ethanol inhibits proliferation in astrocytes, an effect that was recently linked to the suppression of phosphatidic acid (PA) formation by phospholipase D (PLD). The present study investigates ethanol's effect on the induction of apoptosis in astrocytes and the formation of ceramide, an apoptotic signal. Evidence is presented that the formation of PA and ceramide may be reciprocally linked during ethanol exposure. Results In cultured rat cortical astrocytes, ethanol (0.3–1 %, v/v) induced nuclear fragmentation and DNA laddering indicative of apoptosis. Concomitantly, in cells prelabeled with [3H]-serine, ethanol caused a dose-dependent, biphasic increase of the [3H]-ceramide/ [3H…