Search Results
Results 301 - 350 of 1241
< 2 3 4 5 6 7 8 9 10 11 12 >
Lin J T - - 1998
We have examined the biosynthetic pathway of triacylglycerols containing ricinoleate to determine the steps in the pathway that lead to the high levels of ricinoleate incorporation in castor oil. The biosynthetic pathway was studied by analysis of products resulting from castor microsomal incubation of 1-palmitoyl-2-[14C]oleoyl-sn-glycero-3-phosphocholine, the substrate of oleoyl-12-hydroxylase, using ...
Boucrot P - - 1998
Compounds able to inhibit phospholipases A2 can be considered as potential anti-inflammatory drugs. In this respect, the inhibitory effect of the phospholipid analogue 1-decyl 2-octyl-rac-glycero-3-phosphocholine (decyloctyl-GPC) added to the culture medium of rat peritoneal macrophages stimulated with ionophore A23187 was determined. (a) The substrate of phospholipase A2 1-octadecanoyl 2-[14C]eicosatetraenoyl-sn-glycero-3-phosphocholine ([14C]20:4-GPC) ...
Haidl G - - 1997
Previously it was demonstrated that immature and immotile human spermatozoa from the caput epididymides developed a good progressive motility after in-vitro stimulation with phosphatidylcholine (PC). In order to define the role of PC and membrane anisotropy in epididymal maturation and to determine the exact lipid composition of human spermatozoa during ...
Athenstaedt K - - 1997
Lipid particles of the yeast Saccharomyces cerevisiae harbor two enzymes that stepwise acylate glycerol-3-phosphate to phosphatidic acid, a key intermediate in lipid biosynthesis. In lipid particles of the s1c1 disruptant YMN5 (M. M. Nagiec et al., J. Biol. Chem. 268:22156-22163, 1993) acylation stops after the first step, resulting in the ...
Appelblad P - - 1997
A new dansylation reaction, where trifluoromethanesulfonic acid is used as catalyst, has been characterized for six ketosteroids by employing experimental design followed by multivariate data analysis. The molar ratio between the steroid and the derivatization reagent was found to be the factor most strongly affecting the reaction. Faster reaction kinetics ...
Hirano K - - 1997
The properties of phospholipase A1 (PLA1) obtained from the white muscle of bonito, Euthynnus pelamis (Linnaeus), were examined. The PLA1 activity had a pH optimum from 6.5 to 7.0 for phosphatidylcholine (PC), and calcium ion was not required. The optimum temperature was from 20 to 30 degrees C. When a ...
Peres C M - - 1997
[14C]-labelled palmitic acid (PA), oleic acid (OA), linoleic (LA) and arachidonic (AA) acids were transferred from macrophages (M phi) to lymphocytes (LY) when equal numbers of the two cell types were co-cultured. The relative degree and amounts of the fatty acids transferred from M phi to LY are as follow: ...
Durante W - - 1997
Lysophosphatidylcholine (lyso-PC) is a major component of atherogenic lipids that stimulate vascular smooth muscle cell (SMC) proliferation. Because cationic amino acids are metabolized to growth-stimulatory polyamines, we examined whether lyso-PC regulates the transcellular transport and metabolism of cationic amino acids by vascular SMC. Treatment of SMC with lyso-PC initially (0-2 ...
Zheng Z - - 1997
Our previous studies with mice showed that chronic ethanol (EtOH) administration affected the incorporation of unsaturated free fatty acids (FFA) into four major brain phospholipids (PL). In the current study, we investigated the effects of ganglioside GM1 pretreatment on EtOH-induced changes in the incorporation of various FFA into cerebral PL ...
Goldberg E M - - 1997
The individual and combined effects of the saturated diacylglycerol (DAG) dipalmitin (DP) and saturated or polyunsaturated unesterified fatty acids (PUFAs) on both the structure of phosphatidylcholine/phosphatidylserine (PC/PS; 4:1 mol/mol) bilayers and on protein kinase C (PKC) activity were studied using 2H nuclear magnetic resonance (NMR) and enzyme activity assays. In ...
de Rudder K E - - 1997
Phosphatidylcholine (PC) is the major membrane-forming phospholipid in eukaryotes. In addition to this structural function, PC is thought to play a major role in lipid turnover and signalling in eukaryotic systems. In prokaryotes, only some groups of bacteria, among them the members of the family Rhizobiaceae, contain PC. To understand ...
Guidot D M - - 1997
We determined that lisofylline, a potent inhibitor of oleate- and linoleate-containing phosphatidic acid formation (half-maximal inhibitory concentration = 40 nM), prevented oxidant-mediated capillary leak in isolated rat lungs given interleukin-8 (IL-8) intratracheally and perfused with human neutrophils. Lung leak was prevented by lung, but not neutrophil, lisofylline pretreatment. Furthermore, although ...
Schmid P C - - 1997
Freshly isolated rat hepatocytes were incubated for 20 min with [U-14C]glycerol in the presence or absence of unlabeled linoleic (18:2n-6), arachidonic (20:4n-6), or docosahexaenoic (22:6n-3) acid, added as albumin complex in 10% ethanol. Most of the radioactivity (approximately 95%) recovered in hepatocyte lipids was present in phosphatidylcholine (PC), phosphatidylethanolamine (PE), ...
Madesh M - - 1997
Mitochondrial damage is one of the prominent features of cell injury during oxidative stress and altered mitochondrial lipids may contribute to this damage. Lipid changes were observed when liver mitochondria were exposed to superoxide generating systems. Phosphatidylcholine and phosphatidylethanolamine contents were decreased with simultaneous formation of lysophospholipids when exposed to ...
Morris A J - - 1997
Phosphodiesteric cleavage of phosphatidylcholine by members of a growing family of phospholipases D produces choline and phosphatidic acid. These enzymes can also catalyse a transphosphatidylation reaction in which the aliphatic chain of a primary alcohol is transferred to the phosphatidyl moiety of the phosphatidic acid product. PLD enzymes are found ...
Vazquez J M - - 1997
We have investigated pathways of lipid metabolism in spermatozoa and generation of various metabolites with potential messenger functions during exocytosis stimulated with A23187/Ca2+. Stimulation of boar spermatozoa resulted in a considerable rapid increase in saturated/unsaturated 1,2-diacylglycerol (1,2-SU-DAG) and, concomitantly, a substantial reduction in disaturated 1,2-diacylglycerol (1,2-DS-DAG), and in phosphatidylcholine (PC). ...
Schroeder Taylor A T - - 1997
Pathogen-triggered generation of reactive oxidants, termed the oxidative burst, contributes to disease resistance in both plant and animal kingdoms. Since phospholipase D plays a key role in the neutrophil oxidative burst signaling cascade and is highly abundant in plants, we investigated its participation in the plant oxidative burst. Thin layer ...
El Bawab S - - 1997
We have previously reported that concanavalin A (ConA) stimulation of rat thymocytes induces an increase in the cellular phosphatidic acid mass as well as a change in its fatty acid composition. An increase in phosphodiesterase (PDE) activity, mostly due to cAMP-specific (PDE4) isoforms, has also been observed in thymocytes stimulated ...
van der Weyden L - - 1997
This is the first report of a phospholipase A2 (PLA2) from the venom of the common death adder, Acanthophis antarcticus. Acanthoxin is a basic, monomeric PLA2 of mol. wt 13,000, consistent with the weight of neurotoxic PLA2s from other Australian elapids. However, preliminary ultracentrifugation experimentation has shown that it is ...
Kovács P - - 1997
Indomethacin an inhibitor of the cyclooxygenase pathway for arachidonate metabolism in vertebrates, totally inhibited 32P incorporation into phospholipids at a dose of 2.0 or 5.0 mM in Tetrahymena. Treatment with 0.1 mM indomethacin caused higher arachidonic acid (AA) incorporation into phosphatidylinositol (PI) and lower incorporation into phosphatidylcholine (PC), phosphatidylethanolamine (PE), ...
Tóth M - - 1997
The effects of 4beta-phorbol-12-myristate-13-acetate (PMA) and 1,2-(sn)-dioctanoylglycerol (DOCG) on the phosphatidylcholine (PC) turnover (defined as degradation to diacylglycerol followed by PC resynthesis) and on the activity of PC-specific phospholipase D were investigated in placental mince incubated with various radiolabelled precursors in vitro. Experiments with [32P]phosphate indicated that 1 microM PMA ...
Gaits F - - 1997
From very recent studies, including molecular cloning of cDNA coding for membrane receptors, lysophosphatidic acid (LPA) reached the status of a novel phospholipid mediator with various biological activities. Another strong argument supporting this view was the discovery that LPA is secreted from activated platelets, resulting in its appearance in serum ...
English D - - 1997
Phosphatidic acid and its derivatives play potentially important roles as extracellular messengers in biological systems. An ecto-phosphatidic acid phosphohydrolase (ecto-PAPase) has been identified which effectively regulates neutrophil responses to exogenous phosphatidic acid by converting the substrate to diacylglycerol. The present study was undertaken to characterize this ecto-enzyme on intact cells ...
Katsuragi Y - - 1997
PURPOSE: We examined the effects of phospholipids such as phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol (PI), and phosphatidic acid (PA) on human taste sensation to various substances. METHODS: The effects were evaluated psychophysically using paid volunteers. RESULTS: PA inhibited the bitterness of various substances dissolved in water without affecting sweetness, saltiness, and sourness, ...
Garda H A - - 1997
The influence of a fat-free diet on the molecular species composition of phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylinositol (PI) of rat liver microsomes was studied by using reversed-phase high-pressure liquid chromatography. In the three phosphoglyceride classes analyzed, the fat-free diet produced a large decrease in the 18:0/20:4n-6 species but less ...
San-Blas G - - 1997
In Paracoccidioides brasiliensis, a dimorphic fungus pathogenic for humans, no significant differences were observed in the phospholipid species of both morphological phases. The species observed were phosphatidylcholine (PC, 30-40%), phosphatidylethanolamine (PE, 27-28%), phosphatidylserine (16-19%), phosphatidylinositol (13-17%) and sphingomyelin (3-5%). The main fatty acids found in the yeast (Y) phase were ...
Vazquez J M - - 1997
We have investigated pathways of lipid metabolism in boar spermatozoa sperm cells incubated for up to 3 days with [14C]palmitic acid, [14C]glycerol, [14C]choline, or [14C]arachidonic acid or incorporated these precursors into diglycerides and/or phospholipids. When spermatozoa were incubated with [14C]palmitic acid or [14C]glycerol, there was first an incorporation into phosphatidic ...
Tang J - - 1997
We report the purification, molecular cloning, and expression of a novel cytosolic calcium-independent phospholipase A2 (iPLA2) from Chinese hamster ovary cells, which lacks extended homology to other phospholipases. iPLA2 is an 85-kDa protein that exists as a multimeric complex of 270-350 kDa with a specific activity of 1 micromol/min/mg. The ...
Gerasimov O V - - 1997
This laboratory has previously shown (Anderson, V.C. and Thompson, D.H. (1992) Biochim. Biophys. Acta 1109, 33-42; Thompson, D.H., Gerasimov, O.V., Wheeler, J.J., Rui, Y. and Anderson, V.C. (1996) Biochim. Biophys. Acta 1279, 25-34), that plasmenylcholine (1-alk-1'-enyl-2-palmitoyl-sn-glycero-3-phosphocholine; PlsPamCho) liposomes release hydrophilic contents upon photooxidation or acid-catalyzed hydrolysis. We now report the ...
Kozawa O - - 1997
In a previous study, we have that endothelin-1 (ET-1) activates phospholipase D independently from protein kinase C in osteoblast-like MC3T3-E1 cells. It is well recognized that phosphatidylycholine hydrolysis by phospholipase D generates phosphatidic acid, which can be further degraded by phosphatidic acid phosphohydrolase to diacylglycerol. In the present study, we ...
Snitko Y - - 1997
Lysophosphatidic acid (LPA) is a potent lipid second messenger which stimulates platelet aggregation, cell proliferation and smooth-muscle contraction. The phospholipase A2 (PLA2)-catalysed hydrolysis of phosphatidic acid (PA) is thought to be a primary synthetic route for LPA. Of the multiple forms of PLA2 present in human tissues, human secretory class-II ...
Fisher A B - - 1997
Dipalmitoyl phosphatidylcholine (deltaPC) synthesis by lung epithelium occurs in part by a deacylation/reacylation pathway utilizing phospholipase A2 (PLA2) and an acyl transferase. The role of acidic Ca2+-independent PLA2 (aiPLA2) in this pathway was investigated using a transition-state analog enzyme inhibitor [1-hexadecyl-3-trifluoroethylglycero-sn-2-phosphomethanol (MJ33)]. Granular pneumocytes were isolated from rat lung with ...
Bugge E - - 1997
Mepacrine (quinacrine) has in a number of studies been shown to protect the heart from ischemic injury, a protection commonly claimed to be due to inhibition of phospholipase A2. The aim of the present study was to investigate the effect of mepacrine 1 microM on isolated, buffer perfused rat hearts ...
Singh I N - - 1997
Amyloid beta protein (25-35) stimulates the phospholipase A2, C and D activation of LA-N-2 cells. Nordihydroguaiaretic acid reduced the phospholipase D activation by 30% (P < 0.008) and indomethacin reduced the phospholipase A2 activation by 58% (P < .001). There were no reductions of the amyloid beta protein activations by ...
Yu B Y - - 1997
The mechanism behind ethanol-induced fatty liver was investigated by administration of [1,1-2H2]ethanol to rats and analysis of intermediates in lipid biosynthesis. Phosphatidic acid and phosphatidylcholine were isolated by chromatography on a lipophilic anion exchanger and molecular species were isolated by high-performance liquid chromatography in a non-aqueous system. The glycerol moieties ...
Kuwae T - - 1997
Glycerophospholipid biosynthesis by the de novo pathway was assessed in mouse peritoneal macrophages by pulse-labeling with [U-14C]glycerol. Phosphatidylcholine (PC), which amounts to about 35% of total cellular phospholipids, exhibited the highest rate of glycerol uptake, followed by phosphatidylinositol (PI) and phosphatidylethanolamine (PE). Remodeling of PC molecular species by deacylation/reacylation was ...
Wang J - - 1997
Human LCAT prefers phosphatidylcholine (PC) with sn-1-palmitoyl-2-oleoyl PC (POPC) as substrate for cholesteryl ester synthesis, whereas rat LCAT (which is 92% similar in amino acid sequence) prefers sn-1-palmitoyl-2-arachidonoyl PC (PAPC). Six recombinant human LCAT cDNA clones were constructed with unique clusters of rat sequence substitutions in the human background spanning ...
Murakami M - - 1997
Phospholipase A2 (PLA2) plays crucial roles in diverse cellular responses, including phospholipid digestion and metabolism, host defense and signal transduction. PLA2 provides precursors for generation of eicosanoids, such as prostaglandins (PGa) and leukotrienes (LTs), when the cleaved fatty acid is arachidonic acid, platelet-activating factor (PAF) when the sn-1 position of ...
Maeda K - - 1997
Phospholipase A2 (PLA2) catalyzes the release of free fatty acids from membrane phospholipids, and its products derived from these fatty acids, such as prostaglandins and leukotrienes, significantly up-regulate the key melanogenic enzyme, tyrosinase, in melanocytes. This has led to suggestions that PLA2 itself triggers melanin synthesis in melanogenesis following UV ...
Weiher B - - 1997
Digestion and absorption of phosphatidylcholine by Aeshna cyanea larvae were studied in vivo and in vitro with the isolated digestive juice and isolated midgut. The experiments were performed with stable ether analogues (1-alkyl-2-acyl-,1,2-dialkyl phosphatidylcholine, and 1-monoalkyl-lysophosphatidylcholine), with radioactive 1,2-diacylphosphatidylcholine alternatively labelled in the acyl- and choline moieties, and with several ...
Mauco G - - 1997
The strong inhibition of thrombin-induced platelet functions induced by okadaic acid is not correlated with the partial modification of pleckstrin phosphorylation, which remains still phosphorylated two min after stimulation, indicating that protein kinase C is not affected by okadaic acid. We then investigated the effect of okadaic acid on platelet ...
Pacini L - - 1997
In the human neuroblastoma cell line SK-N-BE(2), arachidonic acid (AA), supplied in the medium at micromolar concentrations, markedly enhanced [14C]stearic acid (SA) (but not [14C]palmitic acid or [14C]oleic acid) incorporation into phosphatidylinositol (PtdIns). AA failed to stimulate [14C]SA incorporation into PtdIns precursors, namely phosphatidic acid and cytidinediphosphodiacylglycerol: furthermore, enhanced [14C]SA ...
Lyeth B G - - 1996
Hippocampal levels of fatty acids extracted from phosphatidylinositol 4,5-bisphosphate (PIP2), free fatty acids (FFA), and lactate were measured after central fluid percussion traumatic brain injury (TBI) in rats. At 5 min after injury, there was a decrease in fatty acids extracted from PIP2 suggesting a decrease in PIP2. At the ...
Heape A M - - 1996
In vivo glycerolipid metabolism was studied in sciatic nerves of normal and Trembler mice. The results showed that two kinetically independent pathways were implicated in the labeling of diacylglycerophospholipids from [3H]palmitate: the Kennedy pathway and a 'direct acylation' pathway. In normal nerves, 45% of the glycerophospholipids were labeled, with a ...
Huh N W - - 1996
Because proteins and other molecules with a high polyphenol content are commonly involved in adhesion processes, we are investigating the interactions between polyphenols and biological materials. A naturally occurring polyphenol that binds a variety of proteins and lipids is tannic acid (TA), which contains five digallic acid residues covalently linked ...
Olafsson S O - - 1996
The purpose of this study was to examine the availability of arachidonic acid in phosphatdidylcholine (PC) and phosphatidylethanolamine (PE) of mucosa and the stomach wall of adult male Wistar rats fed a standard diet. There were significant differences in the fatty acid composition of PC and PE between various parts ...
Arai H - - 1996
The reactivity of rabbit reticulocyte 15-lipoxygenase (15-LOX) with phosphatidylcholine (PC) possessing linoleic acid (LA-PC), arachidonic acid (AA-PC), or docosahexaenoic acid (DHA-PC) was investigated by measuring oxygen uptake in the suspension of large unilamellar liposomes (LUV). The 15-LOX reaction with PC LUV was found to follow Michaelis-Menten kinetics. The apparent values ...
Nishimaki-Mogami T - - 1996
The effects of bezafibrate and clofibric acid, fibrate hypolipidemic agents, on phosphatidylcholine (PC) synthesis via the phosphatidylethanolamine (PE) methylation pathway were studied. In cultured rat hepatocytes, bezafibrate and clofibric acid added to the medium rapidly and markedly reduced the conversion of ethanolamine-labeled PE to PC (IC50 30 and 150 microM, ...
Lehr M - - 1996
3-(1,4-Diacylpyrrol-2-yl)propionic acids were designed as inhibitors of cytosolic phospholipase A2. Enzyme inhibition was assayed by evaluation of calcium ionophore A23187-induced arachidonic acid release from bovine platelets. While the synthesized bisacyl compound 3-[3,5-dimethyl-4-octadecanoyl-1-(3-phenylpropionyl)pyrrol-2-yl] propionic acid was inactive at 33 microM, the related monoacylated 3-(3,5-dimethyl-4-octadecanoylpyrrol-2-yl)-propionic acid and 3-(1,3,5-trimethyl-4-octadecanoylpyrrol-2-yl)-propionic acid proved to be ...
Savany A - - 1996
The cytosolic cyclic nucleotide phosphodiesterase (PDE) activity from rat thymocytes was resolved into five peaks by HPLC. Only two forms of the cAMP-specific PDE4 were found to be sensitive to physiologically relevant phosphatidic acid (PA) concentrations. PA activated the PDE4-peak 3 form, the fatty acid composition and unsaturation degree determining ...
< 2 3 4 5 6 7 8 9 10 11 12 >