Search Results
Results 351 - 400 of 1228
< 3 4 5 6 7 8 9 10 11 12 13 >
Legrand A B - - 1996
The incorporation of 12-lipoxygenase metabolites into phospholipids (PLs) could modify second messengers such as diacylglycerols (DAG) and phosphatidic acids. Incubation of [(14)C]12(S)-HETE (1 microM) with bovine pulmonary artery endothelial cells (BPAEC), resulted in its incorporation in PLs with concentration-dependent kinetics. After a 4 h incubation, the proportion of radioactive phosphatidylcholine ...
Nixon A B - - 1996
In human neutrophils (PMN) the ethanolamine-containing phosphoglyceride fraction (PE), principally plasmalogen-linked PE (1-O-alk-1'-enyl-2-acyl-sn-glycero-3-phosphoethanolamine), is the major store of arachidonic acid (AA). Exogenous AA is initially incorporated into 1-acyl-linked phosphoglycerides and is believed to be transferred into the 1-ether-linked phosphoglycerides via the action of a CoA-independent transacylase (CoA-IT). We have investigated ...
Riciputo R M - - 1996
The lipophilic dimorphic yeast Malassezia furfur is a common skin commensal and the aetiological agent of pityriasis versicolor. A source of lipids is essential for its growth, and there are already demonstrations of in vitro lipase and lipoxygenase production. In eight wild strains, isolated from patients with pityriasis versicolor, we ...
Zheng Z - - 1996
Chronic ethanol exposure is known to affect deacylation-reacylation of membrane phospholipids (PL). In our earlier studies we have demonstrated that chronic exposure to ethanol (EtOH) leads to a progressive increase in membrane phospholipase A2 (PLA2) activity. In the current study, we investigated the effects of chronic EtOH exposure on the ...
Lusa S - - 1996
The hydrolysis of pyrenylacyl phosphatidylcholines (PyrnPCs)(n indicates the number of aliphatic carbons in the pyrene-chain) by crude lysosomal phospholipases in vitro was investigated. PyrnPCs consist of several sets in which the length of the pyrene-labelled or the unlabelled acyl chain, linked to the sn-1 or sn-2 position, was systematically varied. ...
Morillo M - - 1996
A simple chemical method for the synthesis of 1,2-diacyl-sn-glycerophosphatidylserine (PS), with the same fatty acid composition in the sn-1 and sn-2 glycerol positions as egg phosphatidylcholine (PC), is described. PS synthesis was carried out by a phosphite-triester approach, using 2-cyanoethyl-N,N,N',N'-tetraisopropylphosphorodiamidite (phosphoramiditate) as the phosphorylating agent, for the formation of phosphate ...
Sugiyama K - - 1996
The effect of dietary eritadenine, a hypocholesterolemic compound found in the mushroom Lentinus edodes, on the fatty acid and molecular species profiles of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) in the plasma and liver microsomes was investigated in relation to the hypocholesterolemic action of the compound in rats. Animals were fed ...
Seidler L - - 1996
Phospholipase D of rat brain synaptosomal membranes was tested with phosphatidylcholine as the substrate for its specificity in the use of primary alcohols as transphosphatidylation co-substrates. The efficiency of the reaction was related to the hydrophobicity and the membrane penetrating capacity of the alcohol molecule. Phosphatidylalcohol formation could be detected ...
Kanfer J N - - 1996
An oleate dependent form of phospholipase D is present in rat brain neuronal nuclei and both the hydrolytic and transphosphatidylation activities measured. Several acidic phospholipids were found to inhibit this activity in a dose dependent manner. The IC50 values varied from 3.5 microM for PIP2 to 200 microM for phosphatidic ...
Beckman B S - - 1996
The generation of the lipid signalling molecules, diacylglycerol (DAG) and phosphatidic acid (PA), has been implicated in the transduction events essential for proliferation of murine B6SUt.EP stem cells responsive to erythropoietin (EPO). Some of the responses were rapid and transient while others were slower and sustained. In an attempt to ...
Vogel G. - - 1996
Many oilseed plants accumulate triacylglycerols that contain unusual fatty acyl structures rather than the common 16- and 18-carbon fatty acids found in membrane lipids of these plants. In vitro experiments demonstrate that triacylglycerols are synthesized via diacylglycerols in microsomal preparations and that this same sub-cellular fraction is the site for ...
Powell G L - - 1996
Tetraoleoylpyrophosphatidic acid (bis phosphatidic acid), when hydrated in aqueous buffer, was shown to form an inverted hexagonal phase using 31P NMR. Low-angle x-ray diffraction provided verification of the formation of this phase in dilute aqueous buffer and in 2 M NaCl and permitted comparison of the tube diameter with that ...
Kim H Y - - 1996
Release of specific polyunsaturated fatty acids for cell membranes may have a significant implication in biological function, considering the involvement of various fatty acids in cell signal transduction. In the present study, release of polyunsaturated fatty acids from rat brain synaptosomes by endogenous synaptosomal lipase activity was examined in comparison ...
Patil S - - 1996
Epidermal enzymes play an important role in the process of differentiation of keratinocytes. The present preliminary in vitro study was undertaken to observe if topical enzyme treatment influenced permeation of compounds across the skin. Due to the noted function and importance of phosphatidylcholine metabolism during maturation of the barrier lipids, ...
Pete M J - - 1996
Phosphatidylcholine (PC) metabolism was investigated using cytosol (fraction I) and particulate fractions of bovine brain that were enriched with microsomes (fraction II), plasma membranes (fraction III) or mitochondria (fraction IV). Fractions I-III incubated with 1-palmitoyl-2-[14C]arachidonoyl-sn-glycero-3-phosphocholine yielded [14C]arachidonic acid at near equal rates, whereas only fraction I accumulated significant amounts of ...
Balsinde J - - 1996
When 388D1 cells are incubated in media containing 10 microM [3H]arachidonic acid (delta4Ach), the label is rapidly incorporated into phospholipids and triacylglycerol. However, incorporation of [3H]delta4Ach into phospholipids clearly precedes incorporation into triacylglycerol, indicating that the phospholipid pool constitutes the primary metabolic fate of the delta4Ach via a remodelling pathway. ...
Boskey A L - - 1996
Acidic phospholipids, complexed with calcium and inorganic phosphate, are components of extracellular matrix vesicles. Both the complexed acidic phospholipids and matrix vesicles have previously been shown to serve as hydroxyapatite (HA) nucleators in solution and when implanted in a muscle pouch. The present study supplies evidence that complexed acidic phospholipids ...
Wolf M J - - 1995
The predominant phospholipase activity present in rat hippocampus is a calcium-independent phospholipase A2 (302.9 +/- 19.8 pmol/mg.min for calcium-independent phospholipase A2 activity vs. 14.6 +/- 1.0 pmol/mg.min for calcium-dependent phospholipase A2 activity). This calcium-independent phospholipase A2 is exquisitely sensitive to inhibition by the mechanism-based inhibitor, (E)-6-(bromomethylene)-tetrahydro-3-(1-naphthalenyl)-2H-pyran -2-one (BEL). Moreover, treatment ...
Cao Y Z - - 1995
Tumor-promoting phorbol esters stimulate the production of phosphatidylethanol (PEt) in bovine lymph node lymphocytes through the activation of Phospholipase D (PLD). Sphingosine enhanced the 12-O-tetradecanoylphorbol-13-acetate (TPA)-mediated formation of PEt in lymphocytes, while it had no effect by itself. Interestingly, the incorporation of labeled arachidonic acid into phospholipids was increased by ...
Williger B T - - 1995
Phosphatidic acid (PA) is a putative novel messenger in signal transduction and membrane traffic. We have synthesized a photolyzable derivative of PA, termed caged PA (cPA), which may be utilized as a new tool in studies of PA-mediated cellular events. 1-(2-Nitrophenyl)diazoethane, synthesized from 2-nitroacetophenone, was reacted with dipalmitoyl-PA to yield ...
Linden D J - - 1995
Cerebellar long-term depression (LTD) may be reliably induced in the cultured Purkinje neuron when glutamate pulses and Purkinje neuron depolarization are applied together 6 times. When the number of these conjunctive stimuli was reduced to 2, a short-term depression (STD) lasting 20-40 min was induced in 4/12 cells. The enzyme ...
DiSanto M E - - 1995
The regulation of phosphodiesterase-4 (PDE4) by various phospholipids was explored using PDE4s partially purified from U937 cells. Preincubation (5 min, 4 degrees C) of the large molecular weight PDE4 denoted "Peak 2 PDE4" with mixed phosphatidic acids (PAs) produced a 2-fold increase in its Vmax without changing its Km (approximately ...
Zhang J P - - 1995
Cerebral insult is associated with a rapid increase in free fatty acids (FFA) and arachidonic acid release has been linked to the increase in eicosanoid biosynthesis. In transient focal cerebral ischemia induced by middle cerebral artery (MCA) occlusion, there is an inverse relationship between the increase in FFA and the ...
Zhou D - - 1995
The present study was aimed at defining the chemotactic activity of phosphatidic acid, which is rapidly produced by phagocytes in response to chemotactic agonists. Exogenously added phosphatidic acid induced human monocyte directional migration across polycarbonate filters with an efficacy (number of cell migrated) comparable to that of "classical" chemotactic factors. ...
Lauener R - - 1995
Activation of phosphatidylinositol 3-kinase (PI 3-kinase) is necessary for stimulation of cell division and inhibition of apoptosis in several cell types. We report that a synthetic phosphonolipid, 4-(hexadecyloxy)-3-(S)-methoxybutyl phosphonic acid (PoA), as well as the naturally occurring lipids, phosphatidic acid and lyso-phosphatidic acid, are potent and specific inhibitors of PI ...
Schmid P C - - 1995
Freshly isolated rat hepatocytes were incubated for 20 and 60 min with [U-14C]glycerol and unlabeled palmitic (16:0), oleic (18:1), or arachidonic (20:4) acid, added as albumin complex in 10% ethanol. Each fatty acid increased glycerol incorporation into total lipids by a factor of 8-10 over control, whereas ethanol alone (final ...
Zabłocki K - - 1995
Renal medullary cells are able to accumulate glycerophosphocholine during adaptation to the high extracellular osmolality. The aim of this study was to investigate the effect of hyperosmolality on both phospholipase A2 activity and the rate of choline incorporation into glycerophosphocholine in rabbit renal medulla and Madin-Darby Canine Kidney cells. Phospholipase ...
Mollner S - - 1995
Incubation of human thrombocytes in the presence of [3H]palmitic acid leads to incorporation of this fatty acid into the alpha subunit of Gs as described [Linder et al., Proc. Natl. Acad. Sci. USA 90 (1993) 3675-3679; Degtyarev et al., Biochemistry 32 (1993) 8057-8061] but also into the catalyst of adenylyl ...
Zhang Q - - 1995
The quantitative distribution of phospholipid (PL) fatty acids from ovine endometrial tissues taken at 105 (n = 3) and 131 and 147 (n = 5) days of gestation age (dGA) and in spontaneous labor (SL, n = 3) is reported. Phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI), phosphatidylserine (PS), and lysophosphatidylcholine ...
He Y - - 1995
Fibroblast contraction of stressed collagen matrices results in activation of a cAMP signal transduction pathway. This pathway involves influx of extracellular Ca2+ ions and increased production of arachidonic acid. We report that within 5 min after initiating contraction, a burst of phosphatidic acid release was detected. Phospholipase D was implicated ...
Ryborg A K - - 1995
Various cell stimuli occur via activation of phospholipase A2, which hydrolyses polyunsaturated fatty acids from the sn-2 position of membrane phospholipids, resulting in the formation of polyunsaturated fatty acids and lysophospholipids. The level of lysophospholipids is determined by the balance between phospholipase A2 activity and the rate of catabolism of ...
Balsinde J - - 1995
Cellular levels of free arachidonic acid (AA) are controlled by a deacylation/reacylation cycle whereby the fatty acid is liberated by phospholipases and reincorporated by acyltransferases. We have found that the esterification of AA into membrane phospholipids is a Ca(2+)-independent process and that it is blocked up to 60-70% by a ...
Henry R A - - 1995
Exposure of adult ventricular myocytes to exogenous natural phosphatidic acid results in the production of inositol phosphates by unknown mechanism(s). We characterized stimulation of myocytic phosphoinositide-specific phospholipase C (PLC) by synthetic dioleoyl phosphatidic acid (PA) as a potential mechanism for modulation of inositol phosphate production. Our data demonstrate that exogenous ...
Rouet-Mayer M A - - 1995
Using the spectrofluorimetric method described by Wittenauer et al. [Wittenauer, L.A., Shirai, K., Jackson, R.L., and Johnson, J.D. (1984) Biochem. Biophys. Res. Commun. 118, 894-901] for phospholipase A2 (PLA2) measurement, we have detected a phospholipase activity in Ailsa Craig and in mutant rin tomatoes at their normal harvest time (mature ...
Puente-Fraga J C - - 1995
Gamma- and delta-isomers of hexachlorocyclohexane caused marked decreases in the levels of radioactive phospholipids, and increases in the levels of [3H]arachidonate incorporated into free fatty acids in rat renal tubular cells. The increased radioactivity of free fatty acids arises from the decrease of [3H]arachidonate incorporated into phosphatidylinositol, but not into ...
DiSanto M E - - 1995
Rolipram inhibited U937 cell phosphodiesterase-4 in either the presence or absence of saturating (100 micrograms/ml) phosphatidic acid in an apparently phospholipid-independent manner, exhibiting similar kinetics (Ki values = 0.41 and 0.59 microM, respectively). At low concentrations (10 and 100 nM), however, rolipram caused a rightward shift of the phosphatidic acid ...
Le Petit-Thevenin J - - 1995
Earlier reports have shown that, in human and rat red blood cells (RBC), ethanol modulates acylation reaction sin several membrane glycerolipid components. Little is known, however, about the kinetics and the mechanisms involved in the acylation changes. In the present study, we show that short-term in vitro exposure of intact ...
Tronchère H - - 1995
Phosphatidylcholine synthesis and degradation are tightly regulated to assure a constant amount of the phospholipid in cellular membranes. The chemotactic peptide fMLP and the phorbol ester, phorbol 12-myristate 13-acetate, are known to stimulate phosphatidylcholine degradation by phospholipase D in human neutrophils. fMLP alone triggered phosphatidylcholine breakdown into phosphatidic acid, but ...
Wang J Y - - 1995
To compare the peroxidative susceptibilities of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) in liposomes, multilamellar vesicles (MLVs) were prepared with equimolar L-alpha-dilinoleoyl PC (DLPC) and L-alpha-dilinoleoyl PE (DLPE), and with soya PC and soya PE having a uniform constituent fatty acids. The hydroperoxide formation at 37 degrees C in the presence ...
Street J C - - 1995
The effect of cyclophosphamide on the metabolic profile of a mammary carcinoma implanted on the foot of mouse was studied by 31P NMR spectroscopy both in vivo and in perchloric acid extracts. The ratio nucleotide triphosphate:P(i) was significantly elevated in cyclophosphamide treated tumours relative to untreated tumours after 96 h ...
Kovács P - - 1995
Phorbol 12-myristate 13-acetate (PMA) treatment elicited an increased 32P incorporation into phospholipids namely phosphatidyl-inositol (PI); phosphatidyl-inositol-4-phosphate (PIP); phosphatidyl-inositol-4,5-bis-phosphate (PIP2); phosphatidyl-acid (PA); phosphatidyl-choline (PC) and phosphatidyl-ethanolamine (PE) particularly at the 20-30th min after treatment. The ratio of members of the phosphoinositol system, especially PIP and PI, related to the total phospholipid ...
Kurscheid-Reich D - - 1995
We tested the hypothesis that serotonin activates phospholipase D (PLD) in cultured rat mesangial cells. The formation of phosphatidylethanol (PET) in ethanol was used as a measure of PLD activity. Serotonin [5-hydroxytryptamine (5-HT)] stimulated PET production, with an initial 10-fold increase in PET content within 15-30 s, followed by a ...
Langner M - - 1995
The partition of free fatty acids (FFA) to egg-phosphatidylcholine (egg-PC) and egg-phosphatidylethanolamine (egg-PE) vesicles was studied. Upon the addition of FFA to the suspension of vesicles, the pH of the aqueous phase changed depending on the length and saturation of the FFA hydrocarbon chain, as well as on the vesicle ...
el Bawab S - - 1995
Several studies have shown the potential role of phosphatidic acid (PA) as a second messenger in different cell types. Thus, PA has been shown to mimic physiological agonists leading to various cellular responses, such as neurotransmitter and hormone release, cell proliferation by modulating DNA or RNA synthesis, the expression of ...
Schmid P C - - 1995
In order to assess the relationship between de novo phospholipid synthesis and remodeling by deacylation-reacylation, we have pulse-labeled glycerolipids by incubating rat hepatocytes in media containing either [U-14C]glycerol or H218O. Further incubation for up to 2 h in the absence of the labeled substrates and analysis of phosphatidylcholine (PC) and ...
Salman M - - 1995
Analysis of Mycoplasma penetrans membrane lipids revealed that, in addition to large amounts of unesterified cholesterol, M. penetrans incorporated exogenous phospholipids, preferentially sphingomyelin, from the growth medium. The major phospholipids synthesized de novo by M. penetrans were phosphatidylglycerol (PG) and diphosphatidylglycerol (DPG). In vivo labeling of PG and DPG by ...
Van Veldhoven P P - - 1995
The phosphorylation of ceramide solubilized in octylglucoside/phosphatidylglycerol mixed micelles by E. coli diacylglycerol kinase was evaluated. Ceramide containing non-hydroxy fatty acids appeared to be phosphorylated quantitatively over a broad range from 25 to 2000 pmoles. If a 2-hydroxy fatty acid was present in the ceramide molecule, phosphorylation was not quantitative. ...
Tou J S - - 1995
The signal transduction pathway of leukotriene B4 involves phospholipase D activation in cytochalasin B-primed neutrophils, but leukotriene B4 stimulation of increased phosphatidic acid mass in neutrophils has not been demonstrated. Employing the NIH Image program, we have examined the effect of leukotriene B4 on phosphatidic acid mass in human neutrophils ...
Bhamidipati S P - - 1995
13C and 31P NMR spectroscopy were used to monitor interactions of lyso 1-palmitoylphosphatidylcholine (LPPC) in the interfacial region of egg phosphatidylcholine (PC) bilayers and determine the effect of LPPC on the phospholipid bilayer structure. 13C NMR spectroscopy of small amounts (0.5-10 mol%) of 13C carbonyl-enriched LPPC cosonicated with egg PC ...
Chapman K D - - 1995
N-acylphosphatidylethanolamine (NAPE) was recently shown to be synthesized in vitro in cottonseed microsomes by the direct N-acylation of phosphatidylethanolamine (PE) with unesterfied fatty acids (K.D. Chapman and T. S. Moore, 1993, Plant Physiol. 102, 761-769). Here we examine the relationship of the synthesis and turnover of NAPE in cottonseed microsomes ...
< 3 4 5 6 7 8 9 10 11 12 13 >