Search Results
Results 201 - 250 of 1228
< 1 2 3 4 5 6 7 8 9 10 >
Zien C A - - 2001
The common plant phospholipase D (PLD), PLDalpha, has been proposed to be involved in wound-induced production of jasmonic acid. To better understand the role(s) of PLDalpha in the wound response, detailed lipid analysis was carried out to determine the in vivo substrates and the contribution of PLDalpha in wound-induced lipid ...
Sultan A - - 2001
An assortment of agents can induce mitochondria to undergo a permeability transition, which results in the inner mitochondrial membrane becoming nonselectively permeable to small (<1500 Da) solutes. This mitochondrial permeability transition (MPT) is characterized by a strict dependence on matrix Ca2+ and sensitivity to cyclosporin A (CsA). However, it is ...
Lee W H - - 2001
Asp49 plays a fundamental role in supporting catalysis by phospholipases A2 by coordinating the calcium ion which aids in the stabilization of the tetrahedral intermediate. In several myotoxins from the venoms of Viperidae snakes, this aspartic acid is substituted by lysine. The loss of calcium binding capacity by these mutants ...
Gangar A - - 2001
Triacylglycerol is one of the major storage forms of metabolic energy in eukaryotic cells. Biosynthesis of triacylglycerol is known to occur in membranes. We report here the isolation, purification, and characterization of a catalytically active cytosolic 10 S multienzyme complex for triacylglycerol biosynthesis from Rhodotorula glutinis during exponential growth. The ...
Schmidt R - - 2001
Impairment of alveolar surfactant function has been documented in the acute respiratory distress syndrome (ARDS) and in severe pneumonia (PNEU); however, the underlying mechanisms are not completely understood. In the current report we present a detailed analysis of fatty acid (FA) profiles of different surfactant phospholipid (PL) classes isolated from ...
Grandbois M - - 2000
Polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS) was used to follow the hydrolysis of phospholipid monolayers at the air-water interface by phospholipase A2 (PLA2). The decrease in the intensity of the nuC=O ester band of dipalmitoylphosphatidylcholine at 1733 cm(-1) and the appearance of two new infrared bands in the 1530-1580 cm(-1) ...
Chatrattanakunchai S - - 2000
Microsomal membrane preparations from Mortierella alpina catalysed the conversion of sn-glycerol 3-phosphate and [(14)C]oleoyl-CoA to radioactive phosphatidic acid, diacylglycerol and triacylglycerol. Experiments with lysophosphatidic acid and [(14)C]oleoyl-CoA gave a similar pattern of radioactivity in the complex lipids. The specific activity of lysophosphatidate acyltransferase was almost eight times greater than sn-glycerol-3-phosphate ...
Morrill G A - - 2000
Progesterone, the physiological inducer of amphibian meiosis, acts within minutes at plasma membrane receptors of the Rana pipiens oocyte to release 1,2-diacylglycerol (DAG) from plasma and intracellular membranes. High-performance liquid chromatography (HPLC) analysis of lipid extracts of uninduced oocytes indicates the presence of at least three classes of DAG with ...
Sarri E - - 2000
We have studied phospholipase D activation in [(32)P]orthophosphoric acid-prelabeled rat pancreatic acini by measuring the formation of (32)P-phosphatidylalcohols as stimulated in the presence of ethanol or butanol. A small but significant and time-dependent basal accumulation of [(32)P]phosphatidylethanol and [(32)P]phosphatidylbutanol was detected, which was further stimulated by phorbol myristate acetate, orthovanadate ...
Banaƛ A - - 2000
We have characterized three CoA-independent types of enzyme, phospholipases, phospholipid:diacylglycerol acyltransferases (PDATs) and cholinephosphotransferases, responsible for the removal of unusual fatty acids from phosphatidylcholine (PC) in microsomal preparations from developing oil seeds. The metabolism of sn-2-[(14)C]acyl-PC was monitored in microsomal preparations from various oilseeds having either medium-chain, acetylenic, epoxy or ...
Fraser T - - 2000
Microsomal membrane preparations from the developing seeds of sunflower (Helianthus annuus L.) catalyse the conversion of sn-glycerol-3-phosphate and acyl-CoA to triacylglycerol via phosphatidic acid and diacylglycerol. The formation of diacylglycerol from phosphatidic acid was Mg2+ dependent and in the presence of EDTA phosphatidic acid accumulated. This property was used to ...
Canavoso L E - - 2000
The pathway for the synthesis of diacylglycerol in larval Manduca sexta midgut was studied. Fifth instar larvae were fed with [9, 10-(3)H]-oleic acid-labeled triolein and the incorporation of the label into lipid intermediates was analyzed as a function of time. The results showed that the triacylglycerol was hydrolyzed to fatty ...
Granier L A - - 2000
BACKGROUND: Neuronal ceroid lipofuscinosis (NCL) is a relatively common group of inherited neurodegenerative disorders characterised by the accumulation of autofluorescent lipopigments (ceroid) similar to lipofuscin. Because of this property, studies have concentrated on fatty acid metabolism and lipid peroxidation. METHODS: In the present study, the fatty acid composition of phosphatidylcholine ...
Rusnak A - - 2000
The incorporation of [1-14C]palmitic or [1-14C]oleic acid into phosphatidylcholine and the effect on blood group antigen expression were examined in human erythrocytes stored at 4 degrees C for 0-3 weeks. Blood drawn into EDTA was obtained by venepuncture from healthy volunteers. A 50% suspension of washed erythrocytes was incubated in ...
Sakamoto T - - 2000
BACKGROUND AND AIMS: Phospholipase D (PLD) hydrolyzes phosphatidylcholine and produces lipid second messengers. Although cellular PLD has recently been recognized as an important signal-transmitting enzyme, the role of PLD in pathophysiologic conditions is largely unknown. In particular, the regulation of PLD in intestinal inflammation has not been previously investigated. The ...
Miyashita M - - 2000
BACKGROUND/AIMS: Phospholipase A2 activity is reported to be related to the physiology of various disorders, and the activity is modified by deoxycholic acid. METHODOLOGY: Serum phospholipase A2 activity was measured by counting the radioactivity of 14C-palmitic acid released from L-3-phosphatidylcholine (1-palmitoyl-2-14C-palmitoyl) in 40 patients with hyperbilirubinemia due to malignant neoplasms ...
El Maghraby G M - - 2000
The aim of this study was to investigate the importance of liposome structure in oestradiol skin delivery as a tool for understanding the delivery mechanism from lipid vesicles. Liposomes of phosphatidylcholine (PC) (1), PC, sodium cholate; 86:14 w/w (II), PC, Span 80; 86.7:13.3 w/w (III) and PC, oleic acid: 84:16 ...
Nishiyama A - - 2000
The proliferation of concanavalin A (Con A)-stimulated rat lymphocytes was markedly inhibited by phosphatidylcholine containing arachidonic and stearic acids (PC(A-S)), but not by phosphatidylcholine containing oleic and stearic acids or phosphatidylinositol containing arachidonic and stearic acids. The concentration of PC(A-S) which inhibited Con A-stimulated proliferation by 50% was 31 microM ...
Saini S S - - 2000
Synthetic melittin mediated the release of [3H]-oleic acid ([3H]-OA) or its acylated lipids from [3H]-OA-labeled E. coli cells exposed to human serum. This phenomenon was not observed in the absence of serum and was calcium independent. The addition of serum was not required for melittin-mediated lysis of erythrocytes, although lysis ...
Chang C Y - - 2000
The synthesis of inflammation mediators produced from arachidonic acid is regulated primarily by the cellular concentration of free arachidonic acid. Since intracellular arachidonic acid is almost totally present as phospholipid esters, the concentration of intracellular arachidonic acid is primarily dependent on the balance between the release of arachidonic acid from ...
Fuly A L - - 2000
An acidic phospholipase A2 isolated from Lachesis muta snake venom denoted LM-PLA2, showed neither toxic nor anticoagulant activities in contrast to a potent inhibitory effect of collagen-induced platelet aggregation [Fuly, A.L., Machado. O.L.T., Alves, E.W. and Carlini, C.R., 1997. Thromb. Haemost 78, 1372-1380.]. Now, the myotoxicity induced by LM-PLA2 was ...
Savitsky A A - - 2000
Covalently bound conjugates of alpha-fetoprotein (AFP) and epidermal growth factor (EGF) with photoheme (PH), 3-desvinyl-3-formylchlorine p6 (Chl p6), chlorine e6 (Chl e6), aluminum disulfochloride phthalocyanine (PC(Al)), and cobalt octa-4,5-carboxyphthalocyanine (teraphthal, TP(Co)) were synthesized. Their molar ratios were 1:4 for AFP-cytotoxin conjugates (cf. 1:10 for AFP-TP(Co)) and 1:2 for EGF conjugates ...
Narita K - - 2000
To better define a therapeutic time window for reducing the extent of damage in ischemic penumbra, the time courses of changes in the glycerophospholipid and free fatty acid (FFA) levels were determined in the rat cerebral cortex following induction of the permanent focal ischemia. Focal ischemia induced a biphasic increase ...
Morita Y S - - 2000
Glycosyl phosphatidylinositol (GPI) anchors in the bloodstream form of Trypanosoma brucei are unusual in that their two fatty acids are myristate. The myristates are added in the final stages of GPI biosynthesis in a remodeling reaction. Remodeling occurs first at the sn-2 position of glycerol, involving removal of a longer ...
Trotter P J - - 2000
Phosphatidic acid is a central intermediate of biosynthetic lipid metabolism as well as an important signaling molecule in the cell. These studies assess the internalization, or retrograde transport, and metabolism of phosphatidic acid in yeast using a fluorescent analog. An analog of phosphatidic acid fluorescently labeled at the sn-2 position ...
Sapirstein A - - 2000
Phospholipases A2 (PLA2s) regulate hydrolysis of fatty acids, including arachidonic acid, from the sn-2 position of phospholipid membranes. PLA2 activity has been implicated in neurotoxicity and neurodegenerative processes secondary to ischemia and reperfusion and other oxidative stresses. The PLA2s constitute a superfamily whose members have diverse functions and patterns of ...
Leondaritis G - - 2000
The unicellular eukaryote Tetrahymena is a popular model for the study of lipid metabolism. Less attention, however, has been given to the inositol phospholipids of the cell, although it is known that this class of lipids plays an important role in eukaryotic cell signaling. Tetrahymena pyriformis phosphatidylinositol was isolated, purified, ...
Ishikawa T - - 2000
Several isozymes of mammalian type 2, Mg(2+)-independent phosphatidic acid phosphatase (PAP-2) have recently been cloned, and they are predicted to have their catalytic sites exposed at the cell surface membranes. We investigated the mode of utilization of extracellular lipid substrates by the human PAP-2b expressed in HEK293 cells as a ...
Utzmann C M - - 2000
While the Maillard reaction of free amino acids and proteins is a well-established process, no defined structures from the nonenzymatic browning of aminophospholipids in foodstuffs have been described so far. Phosphatidylethanolamine (PE)-linked glucosylamines (Schiff-PE), Amadori products (Amadori-PE), 5-hydroxymethylpyrrole-2-carbaldehydes (Pyrrole-PE), and carboxymethyl (CM-PE) as well as carboxyethyl (CE-PE) derivatives were detected ...
Liu J J - - 2000
Digestion of dietary sphingomyelin (SM) is catalyzed by intestinal alkaline sphingomyelinase (SMase) and may have important implications in colonic tumorigenesis. Previous studies demonstrated that the digestion and absorption of dietary SM was slow and incomplete and that the colon was exposed to SM and its hydrolytic products including ceramide. In ...
Parks J S - - 2000
The purpose of this study was to test the hypothesis that lipid fluidity regulates lecithin:cholesterol acyltransferase (LCAT) activity. Phosphatidylcholine (PC) species were synthesized that varied in fluidity by changing the number, type (cis vs. trans), or position of the double bonds in 18 or 20 carbon sn-2 fatty acyl chains ...
Orlati S - - 2000
Sphingosine-1-phosphate (SPP) acts as a first messenger in immortalized human airway epithelial cells (CFNPE9o(-)), possibly interacting with an Edg family receptor. Expression of the SPP receptors Edg-1 and Edg-3, as well as a low level of Edg-5/H218, was detected in these cells, in agreement with their ability to specifically bind ...
Chauhan A - - 2000
Fibrillar amyloid beta-protein (Abeta) is the major protein of amyloid plaques in the brains of patients with Alzheimer's disease (AD). The mechanism by which normally produced soluble Abeta gets fibrillized in AD is not clear. We studied the effect of neutral, zwitterionic, and anionic lipids on the fibrillization of Abeta ...
Grossmann E M - - 2000
Eicosanoids are involved in gallbladder inflammation, epithelial water transport, and mucous secretion. Phospholipase Asubscript2 enzymes liberate arachidonic acid from membrane phospholipids for the synthesis of eicosanoids. The purpose of this study was to determine the effect of selective cytoplasmic and secretory phospholipase A2 inhibitors on basal and stimulated arachidonic acid ...
Mazereeuw-Hautier J - - 2000
Phospholipases A2 (PLA2) catalyse the release of fatty acids from the sn-2 position of phospholipids and have been suggested to play a key part in permeability barrier homeostasis. Using a sensitive and versatile fluorometric method, significant PLA2 activity has been detected in both human skin homogenates and tape strippings of ...
Mongrand S - - 2000
Plastids rely on the import of extraplastidial precursor for the synthesis of their own lipids. This key phenomenon in the formation of plastidial phosphatidylcholine (PC) and of the most abundant lipids on earth, namely galactolipids, is poorly understood. Various suggestions have been made on the nature of the precursor molecule(s) ...
Florin-Christensen J - - 2000
This work examines the lipid composition and metabolism of bovine red blood cells infected by apicomplexan Babesia parasites, organisms closely related to Plasmodium sp. We found that erythrocytes infected with Babesia bovis (i-RBC) accumulate lipids and show striking increases in phosphatidylcholine, phosphatidic acid, diacylglycerol and cholesteryl esters as compared to ...
Baker R R - - 2000
Neuronal nuclei isolated from rabbit cerebral cortex were found to be enriched in an NEM-insensitive lysophosphatidic acid (lysoPA) phosphohydrolase activity. LysoPA is an inhibitor of the nuclear lysophosphatidylcholine (lysoPC) lysophospholipase, and by preserving lysoPC levels, lysoPA boosted the nuclear production of the acyl analogue of platelet-activating factor by promoting the ...
Haftendorn R - - 2000
A series of 1,3-diacylglycero-2-phosphocholines (1,3-PCs) with acyl chain lengths of C8-C18 were synthesised by chemical introduction of the phosphocholine moiety into the regioisomerically pure 1,3-diacylglycerols, which were obtained from glycerol and the vinyl esters of fatty acid by means of lipase from Rhizomucor mihei. The 1,3-PCs being regioisomers of the ...
Kashiwagi T - - 2000
Retinal lipids of crayfish, kept at 4 degrees C under continuous darkness for 3 weeks, consisted mainly of phosphatidylcholine (PC) and phosphatidylethanolamine (PE); sphingomyelin (SM), phosphatidylinositol (PI) and phosphatidylserine (PS) were minor contributors. PI, involved in the phototransduction cascade, never reached greater concentrations than 7% of the total. High concentrations ...
Bertello L E - - 2000
The lipid moiety in the glycosylphosphatidylinositol anchors of glycoproteins of Trypanosoma cruzi consists of an alkylacylglycerol, a lysoalkylglycerol or a ceramide. Previously, we showed that the inositolphosphoceramides (IPCs) are the major components in the precursor inositolphospholipids of epimastigote and trypomastigote forms. Using (3)H-labelled subfractions of IPC, phosphatidylinositol (PI) and glycoinositolphospholipids ...
Florin-Christensen J - - 1999
Phospholipases A(1) and A(2) frequently coexist in biological systems. Generation of lysophosphatidylcholine (LPC) in such systems cannot be assigned to any of these types of enzymes unless the position of the fatty acid in the lysocompound can be unambiguously determined. We here present a simple method to achieve this purpose. ...
Kitsiouli E I - - 1999
The purpose of the present study was the development and evaluation of a fluorimetric method for the screening and differential determination of phospholipase A(2) and PAF-acetylhydrolase in bronchoalveolar lavage (BAL) fluid and serum. Phospholipase A(2) was determined using C(12)-NBD-PC in the presence of Ca(2+), from the slope of the fluorescence ...
Fortes-Dias C L - - 1999
A phospholipase A2 inhibitor has been previously purified and cloned from the blood plasma of the South American rattlesnake, Crotalus durissus terrificus. This inhibitor, named CNF for Crotalus neutralizing factor, interacts with crotoxin, the main neurotoxin from C. d. terrificus venom, abolishing its phospholipase A2 activity. Crotoxin is a heterodimer ...
Lee J Y - - 1999
Brain glycosylphosphatidylinositol-specific phospholipase D (GPI-PLD)-catalyzed conversion of amphiphilic form of Zn2+ -glycerophosphocholine cholinephosphodiesterase (Amp-GPC PDE) into hydrophilic form was investigated in the presence of natural amphiphiles. Monoacylglycerols enhanced considerably the conversion by GPI-PLD of Amp-GPC PDE to hydrophilic form, with the enhancing effect of monoacylglycerols being dependent on the size ...
Rao A M - - 1999
CDP-choline is a rate-limiting intermediate in the biosynthesis of phosphatidylcholine (PtdCho), an important component of the neural cell membrane. The ability of CDP-choline to alter phospholipid metabolism is an important function in the treatment of ischemic injury. Exogenous treatment with CDP-choline stimulates PtdCho synthesis and prevents release of free fatty ...
Pagès C - - 1999
In the present study, we studied the involvement of A2 phospholipases (PLA2) in alpha2-adrenergic receptor-control of preadipocyte actin cytoskeleton. For that, various PLA2 inhibitors were tested on the ability of the selective alpha2-adrenergic agonist UK14304 to induce the spreading in alpha2AF2 preadipocytes. We observed that, whereas several Ca(2+)-dependent PLA2 blockers ...
Sciorra V A - - 1999
Phosphatidylcholine (PC) is a major source of lipid-derived second messenger molecules that function as both intracellular and extracellular signals. PC-specific phospholipase D (PLD) and phosphatidic acid phosphohydrolase (PAP) are two pivotal enzymes in this signaling system, and they act in series to generate the biologically active lipids phosphatidic acid (PA) ...
Chakraborty T R - - 1999
The topography of formation and migration of phosphatidic acid (PA) in the transverse plane of rat liver mitochondrial outer membrane (MOM) were investigated. Isolated mitochondria and microsomes, incubated with sn-glycerol 3-phosphate and an immobilized substrate palmitoyl-CoA-agarose, synthesized both lyso-PA and PA. The mitochondrial and microsomal acylation of glycerophosphate with palmitoyl-CoA-agarose ...
Merkel O - - 1999
The yeast genome contains two genes, designated as PLB2 and PLB3, that are 67% and 62% identical, respectively, to PLB1, which codes for a phospholipase B/lysophospholipase in yeast (Lee, S. K., Patton, J. L., Fido, M., Hines, L. K., Kohlwein, S. D., Paltauf, F., Henry, S. A., and Levin, D. ...
< 1 2 3 4 5 6 7 8 9 10 >