Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Diglycerides”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 901 records · Page 50Linked to original sources
PubMed2001

Investigation on the nutritive value and microbiological quality of wild quail carcasses.

Quail meats have many advantages and superiority one the other species of poultry. This study was planned to throw plenty of light on gross chemical composition, lipid fractions, fatty acids composition, amino acids composition, of thigh and breast of male and female wild quail meat as well as the microbiological quality. The mean values of moisture, protein, fat, ash and energy contents ranged from 60.1 to 69.2%, 55.0 to 68.8%, 28.8 to 42.1%, 2.40 to 3.63% and 696 to 1000 kJ, respectively. Seven fractions of lipids (phospholipids, monoglycerides, cholesterol, diglycerides, free fatty acids, triglycerides and hydrocarbons) were estimated. The individual fatty acids were determined. The mean total unsaturated fatty acids represented 73.9, 66.8, 60.2 and 67.5% of the total fatty acids in thigh male, breast male, thigh female and breast female quail, while that of saturated fatty acids were 25.1, 30.1, 32.0 and 30.4%, respectively. The essential fatty acids in thigh and breast males were 34.8 and 29.0% against 25.7 and 28.1% in females. Amino acids composition were varied from 82.6 to 95.2 g/100 g protein in thigh, breast of male and female wild quails. The essential amino acids were illustrated. The mean values of psychotrophic, Pseudomonas, Enterobacteriaceae, coliforms, Streptococci and Staph. aureus were 4 x 10(4), 1 x 10(2), 4 x 10(3), 3 x 10(3), 6 x 10(2) and 1 x 10(3) cfu/g, respectively. E. coli, Enterobacter agglumerans, E. cloacae, Morganella morgani, Proteus mirabilis, and P. vulgaris could be isolated in varying percentages. Neither Salmonellae nor Clostridium perfringens could be isolated from the examined quails. The public health aspects for the estimated and isolated criteria were outlined.

Amino Acids↗
PubMed1993

Phenytoin-lipid conjugates as potential prodrugs of phenytoin.

Phenytoin-1-triglycerides and phenytoin-2-triglycerides were synthesized as potential prodrugs of phenytoin by covalent binding of 3-hydroxymethylphenytoin by succinic acid to the positions 1 and 2 of diglycerides, respectively. The corresponding 1- and 2-monoglycerides were prepared. In addition, replacement of glycerol by 3-hydroxy-2-hydroxymethylpropionic acid furnished lipids that allowed direct coupling of 3-hydroxymethylphenytoin. The lipid conjugates proved to be substrates for pancreatic lipase in vitro.

Animals↗
PubMed1988

Interleukin-1 stimulation of phospholipase activity in rat synovial fibroblasts. Possible regulation by cyclooxygenase products.

Tritiated arachidonic acid (3H-AA)-labeled rat synovial fibroblasts stimulated with human recombinant interleukin-1 beta (rIL-1 beta) released incorporated radiolabel in a time-dependent and dose-dependent manner, with labeled prostaglandins representing 29% of the released radiolabel. Treatment of the cells with dibutyryl cAMP or prostaglandin E2 enhanced both spontaneous and rIL-1 beta-induced 3H-AA release; treatment with indomethacin or naproxen inhibited the response. The effects of these cyclooxygenase inhibitors on 3H-AA release were not reversed by the addition of prostaglandin E2. The activities of phospholipase A, phospholipase C, and diglyceride lipase were detected in the homogenates of rat synovial fibroblasts. Pretreatment of synovial cells with rIL-1 beta resulted in a threefold stimulation of phospholipase A activity and a slight increase in phospholipase C activity in cell homogenates. These data show that rIL-1 beta stimulates phospholipase activities in rat synovial fibroblasts and that at least one of these activities may be regulated by either prostaglandins or cAMP.

Animals↗
PubMed1991

Crystal-induced neutrophil activation. I. Initiation and modulation of calcium mobilization and superoxide production by microcrystals.

The effects of monosodium urate and calcium pyrophosphate dihydrate crystals on the levels of cytoplasmic free calcium and on the oxidative burst in normal human blood neutrophils were examined. The pattern of sensitivity to granulocyte-macrophage colony-stimulating factor, colchicine, cytochalasin B, pertussis toxin, diglyceride kinase, and protein kinase C inhibitors differentiated the mechanism(s) of neutrophil activation by the crystals from that involved in the responses to soluble chemotactic factors and indicated that individual crystals can use several activation pathways.

Alkaloids↗
PubMed1977

Studies of molecular species of fetal lung lecithins by gas-liquid chromatography mass spectrometry.

The molecular species of lung lecithins obtained from rabbit and rat fetuses at different days of gestation and from newborns were analysed as TMS derivatives of the corresponding diglycerides in a gas chromatograph mass spectrometer system by selected ion retrieval. In the latter part of gestation, the order of the main molecular species of lung lecithins, PCn, was PC32 greater than PC34 greater than PC30, while at an earlier stage it was PC34 greater than PC32 greater than PC30. During gestation the change of PC32:0, dipalmitoyllecithin, was remarkable. Ether lecithins are also discussed.

Animals↗
PubMed2003

Products of phosphoinositide specific phospholipase C can trigger dephosphorylation of cofilin in chemoattractant stimulated neutrophils.

The signal transduction pathways that trigger dephosphorylation of cofilin in neutrophils stimulated with the chemoattractant fMet-Leu-Phe (fMLP) were investigated with a phospho-specific antibody that recognized cofilin only when this protein was phosphorylated on ser-3. Unlike earlier studies that monitored changes in (32)P-labeled cofilin, this Ab allowed us to monitor changes in the total mass of phosphorylated cofilin during neutrophil stimulation. Neutrophils stimulated with fMLP (1.0 microM) for 1.0 min exhibited a massive loss (> 85%) of phosphate from cofilin, which was blocked by an antagonist of phosphoinositide-specific phospholipase C (PI-PLC) (1.0 microM U73122). Products of PI-PLC, sn-1,2-diglyceride and inositol (1,4,5)-trisphosphate, are known to activate protein kinase C (PKC) and increase intracellular Ca(2+), respectively. Treatment of neutrophils with agents that selectively activate PKC [4beta-phorbol 12-myristate 13-acetate (PMA) ] or cellular Ca(2+) (ionophore A23187) also triggered dephosphorylation of cofilin. Both a nonspecific (100 nM staurosporine) and a highly selective antagonist of PKC (200 nM bisindolylmaleimide I) blocked dephosphorylation of cofilin in neutrophils stimulated with PMA but not with fMLP or ionophore A23187. The calmodulin (CaM) antagonists trifluoperazine (15 microM) and W-7 (50 microM) blocked dephosphorylation of cofilin in stimulated neutrophils whereas inactive/less-active analogs of these inhibitors (15 microM promethazine, 50 microM W-5) were substantially less effective. Calyculin A (40 nM), an antagonist of type 1 and 2A protein phosphatases, also triggered a massive dephosphorylation of cofilin in unstimulated neutrophils through a pathway that was insensitive to inhibitors of type 2B phosphatases. These data suggest that both PKC-dependent and independent pathways can trigger dephosphorylation of cofilin in neutrophils with the latter pathway predominating in fMLP-stimulated cells. These pathways may also contain CaM and a type 2C and/or novel phosphatase (e.g., slingshot).

Actin Depolymerizing Factors↗
PubMed1980

Lipolytic activity of poppy seed.

Crude lipase emulsion from poppy seed hydrolyses its endogenous substrate at an optimum pH of 4.9 and optimum temperature of 22--25 degrees C. The lipase emulsion is stable up to 50 degrees C. The enzyme is activated by low concentration of calcium ions; at higher concentrations a partial activity drop occurs. The addition of sodium chloride decrease the lipase activity, whereas casein, whey and bovine serum albumin stimulate its activity. The addition of sucrose does not affect the activity. During the enzymic reaction triglycerides are hydrolyzed yielding diglycerides, free fatty acids and to a lower extent monoglycerides as well.

Drug Stability↗
PubMed1988

Thrombin and histamine activate phospholipase C in human endothelial cells via a phorbol ester-sensitive pathway.

The effects of phorbol esters and synthetic diglycerides on thrombin- and histamine-stimulated increases in inositol trisphosphate (IP3) and cytosolic free calcium [( Ca2+]i) were studied in cultured human umbilical vein endothelial cells (HEC). Thrombin (0.003-3.0 U/ml) and histamine (10(-7)-10(-4) M) induced rapid increases in [Ca2+]i in suspended cells as monitored with the fluorescent calcium indicator fura-2. In [3H]myoinositol-labeled cells, both thrombin (3 U/ml)- and histamine (10(-4) M)-induced IP3 increases (195% +/- 6% and 98% +/- 4%, respectively) occurred in less than 15 sec and were temporally correlated with [Ca2+]i increases. Brief incubations (5-60 min) with different protein kinase C activators [4-beta-phorbol 12-myristate 13-acetate (1-100 nM), mezerein (100 nM), and sn-1,2 dioctanoylglycerol (0.1-10 microM)] attenuated agonist-induced increases in [Ca2+]i. These compounds also inhibited thrombin- and histamine-stimulated IP3 formation, thus suggesting a tight coupling between phospholipase C activation and calcium flux in cultured HEC. Overall, these observations suggest that the pathway linking receptors to phospholipase C stimulation in human endothelial cells is sensitive to protein kinase C activation.

Calcium↗
PubMed1992

Endothelin stimulates phosphatidic acid formation in cultured rat mesangial cells: role of a protein kinase C-regulated phospholipase D.

We have previously reported that endothelin-1 stimulates phospholipase C-induced hydrolysis of phosphatidylinositol-4,5-bisphosphate. Other signal transduction pathways that hydrolyze alternative phospholipids through phospholipase D may also mediate endothelin-stimulated cellular responses. We initially evaluated endothelin-dependent generation of 32P-phosphatidic acid as an indirect indication of phospholipase D activity in rat mesangial cells. Endothelin (10(-7) M) induced an elevation of phosphatidic acid that was maximal at 15 min and persisted upward of 60 min. Pretreatment with the diacylglycerol-kinase inhibitor, R59022, did not reduce formation of endothelin-stimulated 32P-phosphatidic acid, demonstrating that the sequential actions of phospholipase C/diacylglycerol kinase do not contribute to endothelin-stimulated phosphatidic acid formation. We next conclusively identified a role for phospholipase D in the generation of phosphatidic acid by assessing the formation of 3H-phosphatidylethanol from 3H-alkyl lyso glycerophosphocholine and exogenous ethanol. Endothelin stimulated 3H-alkyl phosphatidylethanol formation in the presence but not the absence of 0.5% ethanol. Also, endothelin induced a concomitant elevation of 3H-alkyl-phosphatidic acid that was significantly reduced when the cells were exposed to exogenous ethanol, reflecting the formation of phosphatidylethanol. In addition, endothelin stimulated the release of 3H-choline and 3H-ethanolamine, demonstrating that additional phospholipids may serve as substrates for phospholipase D. Phorbol esters and synthetic diglycerides mimicked the effects of endothelin to stimulate phospholipase D and inhibitors of protein kinase C significantly reduced endothelin-stimulated phospholipase D. In addition, endothelin did not stimulate phosphatidylethanol formation in protein kinase C down-regulated cells. The calcium ionophore, ionomycin, did not stimulate phospholipase D and mesangial cells pretreated with BAPTA to chelate cytosolic calcium did not show a diminished endothelin-stimulated phospholipase D. Thus these data demonstrate that mesangial cells possess a protein kinase C-regulated phospholipase D activity that can be stimulated with endothelin.

Animals↗
PubMed2004

Enhanced oral bioavailability of poorly absorbed drugs. I. Screening of absorption carrier for the ceftriaxone complex.

In this study, we attempted to improve the oral absorption of ceftriaxone (CTX) by using an absorption carrier and the CTX complex together. After the CTX-Ca-carrageenan gel complex was prepared, several kinds of compounds (Capmul MCM C10, Gelucire 44/14, glycyrrhizin) were screened as potential oral enhancers for our experiment and the intestinal morphologies in rats were examined. Of these compounds, the mono- and diglyceride mixtures, Capmul MCM C10 greatly enhanced the gastrointestinal absorption of CTX when this carrier was coadministered with the complex in rats. Percent bioavailability was attained in rats by the enteral route ranging from 55 to 79% when this complex was administered with various doses of Capmul MCM C10. Furthermore, the surface morphology of the complex has a highly smooth appearance as seen under scanning electron microscopy after preparation. No treatment-related signs of any damage were observed on the administrations intestinal membrane when morphologies were examined in rats after the complex and the absorption carrier were coadministered. The results of the observation suggest that Capmul MCM C10 is a promising carrier, having a good balance between bioavailability enhancing activity and safety, for the oral delivery of CTX when it is coadministered with complex.

Absorption↗
PubMed2006

Determination of beef tallow in lard through a multidimensional off-line non-aqueous reversed phase-argentation LC method coupled to mass spectrometry.

The presence of tallow in lard is not easy to determine, due to the similarity of the composition of these two animal fats, which differ mainly in the distribution of fatty acids (FA) in the three positions of the glycerol molecule. The determination of the composition of the triacylglycerol (TAG) fraction of lard, tallow, and their mixtures was investigated by HPLC in combination with atmospheric pressure chemical ionization mass spectrometry (APCI-MS). The presence of tallow in lard was determined through the study of the sn-POP/sn-PPO ratio by multidimensional HPLC. The off-line bidimensional system was attained through the coupling of non-aqueous reversed phase (NARP)-HPLC and silver ion (Ag)-HPLC. The primary column eluate was fractionated and the fraction containing POP/PPO isomers was injected onto the secondary column, allowing the separation of positional isomers, unresolved in the first dimension. Peak assignment was carried out by combining retention data with APCI-MS spectral information. The fatty acid distribution along the glycerol backbone, determined by Ag-HPLC, was confirmed through diglyceride ion ratios derived from APCI-MS analysis. Method validation was carried out in preliminary applications on standard TAGs. The analytical results obtained show that even a 5% addition of tallow to lard modifies the distribution of positional isomers.

Animals↗
PubMed2003

Matrix-assisted laser desorption/ionization analysis of lipids and high molecular weight hydrocarbons with lithium 2,5-dihydroxybenzoate matrix.

Lithium 2,5-dihydroxybenzoate (LiDHB) is shown to be a very effective matrix for matrix-assisted laser desorption/ionization (MALDI) analysis of nonpolar long-chain lipids, hydrocarbons and polymers. Under standard desorption and ionization conditions using a conventional nitrogen UV laser (337 nm), hydrocarbons (C(24)-C(40)), diverse lipids (triglycerides, diglycerides, wax esters from leaves) and saturated polymers are effectively lithiated providing [M+Li](+) ions. The formation of lithiated hydrocarbons is not accompanied by an elimination of hydrogen or other fragmentation reactions and, due to the relatively simple isotopic distribution of lithium, seems to be more useable for analysis of hydrocarbon mixtures than the previously used silver cationization agents. The mass calibration can be conveniently performed either externally or internally using poly(ethylene glycol) commercial standards.

Gentisates↗
PubMed2006

Examining the collision-induced decomposition spectra of ammoniated triglycerides as a function of fatty acid chain length and degree of unsaturation. II. The PXP/YPY series.

A series of positionally pure triglycerides (TAGs) of the form PXP and YPY, where P is the palmitate moiety and X and Y are large arrays of different fatty acid moieties, is synthesized and analyzed by reversed-phase high-performance liquid chromatography/tandem mass spectrometry. The intensities of the collision-induced decomposition (CID) products of ammoniated TAGs were examined as a function of chain length, degree of unsaturation, double-bond position, and cis/trans configuration of X and Y. The major CID products, the diglyceride (DAG) fragment ions and the MH(+) ions, are plotted as functions of chain length for the saturated and monounsaturated series of X and Y. Different trends for each of these series are observed. Trends in the intensities of these fragment ions are also characterized as a function of degree of unsaturation in the TAGs. In general, the fractional intensities of MH(+) increase with increasing degree of unsaturation in the TAGs. MH(+) is absent in the CID spectra of triglycerides containing three saturated fatty acid moieties, suggesting that the presence of double bonds fosters the formation of MH(+). Double bonds positioned close to the carbonyl carbon along the fatty acid chain promote the formation of the DAG fragment ion corresponding to the loss of the fatty acid. The collection of PXP/YPY data produced in this work is used to test the mechanisms of the formation and decomposition of ammoniated TAGs that were previously presented. The YPY data are used to predict the intensities of the fragment ions in the CID spectra of YPX-type TAGs. The limitations of the mathematical approach used in these predictions are discussed in context of a broader plan to develop a software platform for comprehensive analysis of complex TAG mixtures.

Chromatography, High Pressure Liquid↗
PubMed1997

Inhibition of GTP gamma S-dependent phospholipase D and Rho membrane association by calphostin is independent of protein kinase C catalytic activity.

We studied the relationships between the activation of phospholipase D (PLD) by guanine nucleotides and phorbol esters in permeabilized U937 promonocytes and in solubilized extracts prepared from U937 cell membranes. Treatment of permeabilized cells with phorbol myristate acetate (PMA) strongly potentiated GTP gamma S-dependent PLD activity at free Ca2+ < 100 nM. In the absence of GTP gamma S, PMA stimulated only minor PLD activity. This suggested synergistic interaction between regulatory G-proteins and a protein kinase C (PKC) family kinase. The potential role of PKC was evaluated by testing two mechanistically distinct PKC inhibitors, bisindolylmaleimide (BIM) and calphostin. BIM inhibits PKC enzymes via competition with ATP for binding to the catalytic domain, while calphostin competes with PMA or diglyceride for binding to the regulatory domain. The ability of PMA to potentiate the GTP gamma S-dependent PLD was not inhibited by BIM. In contrast, calphostin strongly inhibited the GTP gamma S-dependent PLD activity, both in the presence and absence of PMA as a potentiating agent. Calphostin also produced complete inhibition of a GTP gamma S-dependent PLD activity, present in solubilized membrane extracts, which was assayed using phospholipid vesicles of defined composition. Treatment of reconstituted membrane/cytosol mixtures with calphostin also produced complete inhibition of the GTP gamma S-induced translocation of Rho A from cytosol to membrane. In contrast to its effects on the U937 cell PLD, calphostin did not inhibit the activity of purified PLD from cabbage. These results suggest that the assembly of active RhoA/PLD signaling complexes on membranes involves a phorbol ester/calphostin-binding protein, but is not dependent on PKC-type catalytic activity.

Blotting, Western↗
PubMed1994

Characterization of chain-shortened oxidized glycerophosphocholine lipids using fast atom bombardment and tandem mass spectrometry.

Oxidized glycerophosphocholine (GPC) lipids produced by free-radical-initiated lipid peroxidation have been reported to activate human polymorphonuclear leukocytes exerting an effect through the platelet-activating factor receptor, yet few methods have been developed to characterize intact oxidized phospholipids, which may be present in small quantities. In this paper we detail the fast atom bombardment and collision-induced dissociation behavior of 1-hexadecanoyl-2-(5-oxopentanoyl)-GPC and 1-hexadecanoyl-2-pentanedioyl-GPC, two prototypic oxidized glycerophosphocholine lipids produced by hydroxyl radical-initiated peroxidation of 1-hexadecanoyl-2-arachidonoyl-GPC. Identities of these two products were established first using EI-GC/MS to analyze the corresponding diglyceride tert-butyldimethylsilyl ether derivatives. The aldehyde moiety of 1-hexadecanoyl-2-(5-oxopentanoyl)-GPC was found to react with FAB amine-containing liquid matrices (e.g., diethanolamine) to form an oxazolidine derivative (87 u increase in mass). No reaction was observed with matrices such as glycerol, thioglycerol, and 3-nitrobenzylalcohol. This derivatization can be used to distinguish an aldehyde-containing oxidized phospholipid from isobaric species not containing an aldehyde moiety. Results also showed that 1-hexadecanoyl-2-pentanedioyl-GPC formed primarily [M-H]- ions rather than the [M-15], [M-60], and [M-86] negative ions expected for GPC lipid species. The ionized omega-carboxyl group of the sn-2 substituent allowed the phosphocholine moiety to remain as a zwitterion. Following collision-induced dissociation, a N-methyl group from the choline was transferred to the omega-carboxyl of the sn-2 substituent prior to generation of the carboxylate anions, which resulted in a 14-u increase in the observed sn-2 carboxylate anion.(ABSTRACT TRUNCATED AT 250 WORDS)

Glycerylphosphorylcholine↗
PubMed1997

Radiolabeling of the lipids of chinese hamster ovary cells with the probe [3-(trifluoromethyl)-3-(m-[125I]iodophenyl)diazirine].

[125I]TID [3-(trifluoromethyl)-3-(m-[125I]iodophenyl)diazirine] is a commercially available, hydrophobic, photoactivatable, gamma-emitting reagent mostly used to label protein hydrophobic domains. It has also been used to radiolabel the phospholipids of lung surfactant (Gilliard et al., Anal. Biochem. 193, 310-315, 1991). Since a nonspecific, highly sensitive, lipid-labeling probe would be a very useful tool to investigate lipid-protein interactions in biological membranes, we characterized further the [125I]TID-labeling products of lipids from cultured Chinese hamster ovary cells (IR-CHO). After labeling of whole cells, TLC analysis followed by autoradiography enabled detection of sphingomyelin, phosphatidylcholine, phosphatidylinositol, phosphatidylserine, phosphatidylethanolamine, cardiolipin, diglycerides, cholesterol and its esters, and triglycerides. Analysis of the radioactivity associated with the saponification products of different lipids showed that [125I]TID was mostly (80%) extracted with the fatty acid moiety of the lipids whereas 20% remained associated with the hydrosoluble moiety. Similar radioactivity profiles were observed after labeling of whole cells or extracted and liposome-reconstituted lipids; the [125I]TID probe was able to diffuse in all intracellular organelles. Labeling was not equivalent between the different lipid classes, and it appeared that the amount of associated radioactivity correlated well with the degree of lipid unsaturation. This was confirmed by studying [125I]TID incorporation in phosphatidylcholines of different chain length and unsaturation. Taken together, our data demonstrate that [125I]TID can be used as a radiolabel for lipids in cultured cells. It is rapidly incorporated in the hydrophobic part of membranes, diffuses into all cellular compartments, and labels all lipid classes, including phospholipids, cholesterol, and glycerides, with a sensitivity in the nanomolar range.

Animals↗
PubMed1995

The identification and partial characterisation of a novel inducible extracellular thermostable esterase from the archaeon Sulfolobus shibatae.

Extracellular esterases have so far only been reported in eubacteria, here we report the first identification and partial characterisation of a novel inducible extracellular esterase from the thermoacidophilic archaeon Sulfolobus shibatae. This esterase exhibits remarkable stability to both acid and heat. Esterase activity is induced by growth on a range of polyoxyethylenesorbitan (Tween) compounds as sole carbon source. Activity occurs over a wide temperature (25-99 degrees C) and pH (pH4.0-9.0) range and is optimal at 90 degrees C and pH6.0. It exhibits high thermal stability, with a half-life of 20 min at 120 degrees C, and shows a transient thermal activation of 60% at 90 degrees C. The thermal inactivation of function occurs by first order kinetics, and after 120 min incubation at 120 degrees C 50% of activity still remains. It is able to hydrolyse mono- and diglycerides, but is unable to hydrolyse the triglycerides olive oil and triolein, which is indicative of an esterase and not a lipase.

Enzyme Induction↗
PubMed1995

Molecular analysis of Ras activation by tyrosine phosphorylated Vav.

Vav has been shown to activate Ras (1-3) and is regulated by tyrosine phosphorylation (1) or binding of diglycerides (3) to the cysteine rich domain. In the present study employing different Ras activation assay techniques using [3H]GDP release or [32P]alpha GTP-binding from membrane-bound or soluble recombinant Ras, we demonstrate that Ras activity can be increased by tyrosine phosphorylated Vav upon cellular stimulation via the IL-2 receptor or the TCR/CD3-complex. Increase of [32P]alpha GTP-binding to Ras catalyzed by phosphorylated Vav is similar to the activity of immunoprecipitated Sos. The activity of Vav measured by binding of [32P]alpha GTP to Ras was linear with respect to the concentration of Vav protein used. To study molecular characteristics of this Vav-Ras interaction, we used several Ras mutants and demonstrate that Vav activity towards Ras depends on the integrity of the same or similar domains as Ras activation by SDC 25 or CDC 25.

CD3 Complex↗