Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “GLYCERIDES”

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 757 records · Page 42Linked to original sources
PubMed1999

Direct mass spectrometric analysis of Bacillus spores.

Spores from the Bacillus species, B. cereus, B. anthracis, B. thuringensis, B. lichenformis, B. globigi, and B. subtilis, were examined by direct probe mass spectrometry using electron ionization (EI) and positive and negative chemical ionization (CI). Molecular ions from free fatty acids and nucleic acids were observed in the 70eV spectra as were fragments from glycerides. Spectra obtained with isobutane positive chemical ionization (CI(+)) were dominated by ions associated with pyranose compounds such as N-acetylglucosamine (NAG). Unlike the positive ion spectra, the negative ion spectra of the spores were very simple and contained few peaks. The M(-.) ion from dipicolinic acid (DPA) was the base peak in the negative ion spectra of all spore species except those from B. lichenformis. The negative ion of DPA produced such a strong signal that 10(8) colony forming units (CFUs) of B. cereus spores could be detected directly in 0.5 g of ground rice. Principal component analysis (PCA) of the spectra revealed that only CI(+) spectra contained differences that could be used to identify the spectra by species. Differentiation of the CI(+) spectra by PCA was attributed to variances in the peaks associated with the bacterial polymer poly(3-hydroxybutyrate) (PHB) and NAG. Similar differences in PHB and NAG peaks were detected in the CI(+) spectra of a suite of vegetative Bacillus stains grown with various media.

Acetylglucosamine↗
PubMed1991

[The characterization of microbial lipases. 2. The determination of lipase specificity].

Types of lipase specificity are as follows: Positional specificity; fatty acid specificity; stereospecificity; substrate specificity (different rates of lipolysis of different glyceride classes. The acylglycerol used for determination of lipase specificity must be so structured, that specificities are not confused and unambiguous results are obtained. Different substrates and methods for detection of specificity are reviewed and advantages and disadvantages are discussed. Positional specificity can be determined with synthetic dialkylacylglycerols and 2,3-dioleoyl butanediol. Stereospecificity can be detected with enantiomeric dialkylacylglycerols or diacylalkylglycerols.

Amino Acid Sequence↗
PubMed1985

Diacylglycerols and mezerein activate neutrophils by a phorbol myristate acetate-like mechanism.

rac-1-O-Myristoyl-2-O-acetylglycerol, rac-1-O-palmitoyl-2-O-acetylglycerol, and rac-1-O-oleoyl-2-O-acetylglycerol acted like phorbol myristate acetate and mezerein in stimulating human neutrophil aggregation. Responses to these agents were equally influenced by cytochalasin B, extracellular calcium and magnesium, arachidonate antimetabolites, and procedures that rendered the cells desensitized to other agonists. The compounds also inhibited the binding of [3H]-phorbol myristate acetate to its receptor on neutrophils. Thus, these agents are biologically homologous. They act by binding to a common receptor. This receptor may function physiologically as a transducer for endogenous glycerides that form in cells challenged by other stimuli.

Arachidonic Acid↗
PubMed1985

Metabolism of methanol by yeast and SCP production.

The utilization of methanol by Candida lipolytica was studied with respect to the biomass, protein, lipid and other metabolites contents. Supplementation of the methanol medium with certain redox agents such as 2,6-dichlorophenol indophenol, reduced glutathione and methyl red, showed a stimulation of both growth and protein production of C. lipolytica. At certain growth conditions the cellular yield of C. lipolytica was 0.3 g of cells/g of methanol and the protein of the biomass was 41.0%. The amino acid composition of the protein especially of the essential ones was comparable to FAO standards. Thin-layer chromatography of the lipids indicated a dominance of total glycerides. Analyses of the acylated unsaponified fraction by gas liquid chromatography showed that campesterol was the major component.

2,6-Dichloroindophenol↗
PubMed2007

Evaluation of hydroperoxides in common pharmaceutical excipients.

While the physical properties of pharmaceutical excipients have been well characterized, impurities that may influence the chemical stability of formulated drug product have not been well studied. In this work, the hydroperoxide (HPO) impurity levels of common pharmaceutical excipients are measured and presented for both soluble and insoluble excipients. Povidone, polysorbate 80 (PS80), polyethylene glycol (PEG) 400, and hydroxypropyl cellulose (HPC) were found to contain substantial concentrations of HPOs with significant lot-to-lot and manufacturer-to-manufacturer variation. Much lower HPO levels were found in the common fillers, like microcrystalline cellulose and lactose, and in high molecular weight PEG, medium chain glyceride (MCG), and poloxamer. The findings are discussed within the context of HPO-mediated oxidation and formulating drug substance sensitive to oxidation. Of the four excipients with substantial HPO levels, povidone, PEG 400, and HPC contain a mixture of hydrogen peroxide and organic HPOs while PS80 contains predominantly organic HPOs. The implications of these findings are discussed with respect to the known manufacturing processes and chemistry of HPO reactivity and degradation kinetics. Defining critical HPO limits for excipients should be driven by the chemistry of a specific drug substance or product and can only be defined within this context.

Cellulose↗
PubMed1993

Effect of various vehicles on ketoprofen permeation across excised hairless mouse skin.

The effects of glycerides, short-chain alcohols, and their binary vehicles as donor components on the permeation of ketoprofen (KP) across the excised hairless mouse skin were evaluated with the modified LOVEDAY-type diffusion cell. Among single vehicles, Panasate 800 as tricaprylin appeared to be the most favorable lipophilic vehicle, with no toxicity and with a short lag time (0.9 h), and methanol (MeOH) or ethanol (EtOH) as hydrophilic single vehicles showed the highest KP permeation flux (244.1 and 134.1 micrograms/cm2/h, respectively). Furthermore, KP permeation was enhanced remarkably by the combination of EtOH and Panasate 800 compared with each single vehicle as reflected in the decreased lag time and increased flux. The greatest enhancement was observed in the EtOH/Panasate 800 (40/60) binary vehicle (permeation ratio at 24 h, 40.0%; steady-state flux, 314.0 micrograms/cm2/h; lag time, 3.7 h). Further investigations involving stripping studies and KP accumulation within the skin were performed to explain the mechanism of enhancement caused by the above binary vehicle. It was suggested that the mutual enhancement effect of EtOH/Panasate 800 (40/60) binary vehicle is due to decreasing the barrier ability of the stratum corneum by EtOH and the viable skin by Panasate 800.

Alcohols↗
PubMed1978

Turnover of lipids in Mycobacterium smegmatis CDC 46 and Mycobacterium phlei ATCC 354.

The rates of breakdown and renewal of individual lipids in cultures of Mycobacterium smegmatis CDC 46 and Mycobacterium phlei ATCC 354 were investigated by means of a pulse labelling technique using palmitate-1-14C. The results indicated that in growing cultures of both strains phospholipids were broken down, and cardiolipin had a very rapid turnover. In chase experiments, almost 45% and 40% of the radioactivity of this component were lost respectively from M. smegmatis and M phlei during one generation time of the cell. The other two major components, phosphatidyl ethanolamine and phosphatidylinositol mannosides showed relatively low turnover. The loss of radioactivity from phosphatidylinositol mannosides was greater in M. phlei than in M. smegmatis but the loss of radioactivity from phosphatidyl ethanolamine was higher in M. smegmatis. The pattern of loss of radioactivity from lipids was almost the same in both strains, the difference being only in the extent of loss. The differences in the cellular localization of the phospholipids indicate their different roles within the cell. Results obtained with the glyceride fraction indicated a very rapid turnover of triglycerides in both strains.

Glycerides↗
PubMed1983

Effect of undecanoic acid on lipid composition of Trichophyton rubrum.

Phospholipid and neutral lipid composition of undecanoic acid (UDA) resistant mutant of Trichophyton rubrum were compared with those of the UDA sensitive parent strain of this dermatophyte. When grown in glucose-peptone broth under identical conditions, contents of neutral and phospholipids in UDA resistant mutant were nearly double of those in the UDA sensitive parent strain. Glyceride, sterol, sterol ester and phospholipid contents of mycelium increased when UDA sensitive strain was grown in presence of low concentration of UDA, sufficient to cause partial growth inhibition of this strain. UDA in growth medium did not change the lipid composition of the UDA resistant mutant.

Drug Resistance, Microbial↗
PubMed1980

Liver lipids in Letterer-Siwe disease.

A case of Letterer-Siwe disease in a thirteen-month-old girl with markedly swollen gums, an enlarged liver, and seborrhoic skin eruptions is reported. She died from pyopneumothorax in spite of treatment with prednisolone and vinblastine. Analysis of hepatic lipids showed that there was remarkable increase in free fatty acid, which is not seen in normal human liver. Cholesterol ester was also accumulated in the liver tissue. However, the concentrations of phospholipids and glycerides were low and lysophospholipid was found. It is assumed that there was increased intracellular lipolysis in the proliferating reticuloendothelial cells.

Cholesterol Esters↗
PubMed1985

Effect of various drugs producing convulsive seizures on rat brain glycerolipid metabolism.

Convulsive seizures were elicited in the rat by the injection of several different drugs (pyridoxal phosphate, bicuculline, penicillin and ouabain). Glycerolipid metabolism was studied after the intraventricular injection of [2-3H]glycerol, which was incorporated into rat brain glycerides. The percentage of total lipid label found in each lipid class (phosphatidylethanolamine, PE; phosphatidylcholine, PC; phosphatidylserine, PS; phosphatidic acid, PA; phosphatidylinositol, PI; diacylglycerol (+ monoacylglycerol), DG and triacylglycerol, TG) depended on the time elapsed from the injection of the labeled precursor. The percent of total lipid radioactivity as PE and PC increased with time (3-60 min), whereas the opposite was true for the radioactivity of DG and PA. The radioactivity of other lipid classes did not appreciably vary between 3 and 60 min from the injection of the labeled glycerol. The intraventricular administration of pyridoxal phosphate together with labeled glycerol decreased the percent of lipid radioactivity as PE and increased that as DG. This 'lipid effect' was detected also after the administration of other convulsants, such as ouabain and penicillin. The intraperitoneal administration of bicuculline affected lipid metabolism in cerebellum.

Animals↗
PubMed1983

Deficiency of taurocholate-dependent phospholipase C acting on phosphatidylcholine in Niemann-Pick disease.

Examination of release of labeled glyceride from 2-[1-14C]oleoyl phosphatidylcholine by a soluble extract of human fibroblasts confirmed the presence of phosphodiesterase which is stimulated strongly by sodium taurocholate. This activity was maximal at pH 4.5 and was inhibited by sphingomyelin and 5' AMP. Assay of the phosphatidylcholine phosphodiesterase activity in fibroblast cultures from patients with Niemann-Pick disease revealed a severe deficiency in those cultures also deficient in sphingomyelinase (3 type A and 4 type B) whereas assay of cultures from Niemann-Pick patients without sphingomyelinase deficiency (3 type C and 1 with neurovisceral lipidosis and vertical supranuclear ophthalmoplegia) gave activities similar to controls. The distribution of label in the products of the reactions catalyzed by both control and Niemann-Pick extracts indicates that the phosphodiesterase activity observed was phospholipase C and that phospholipase D was not involved. The close correlation of phosphatidylcholine phospholipase C and sphingomyelinase activities in the control and mutant fibroblasts strongly suggests that both activities are catalyzed by one enzyme. Various alterations in the regulation of the specificity of a multifunctional phospholipase C may underlie phenotypic variation in Niemann-Pick disease.

Cell Line↗
PubMed1986

Reduced labeling of brain phosphatidylinositol, triacylglycerols, and diacylglycerols by [1-14C]arachidonic acid after electroconvulsive shock: potentiation of the effect by adrenergic drugs and comparison with palmitic acid labeling.

The effect of electroconvulsive shock on the labeling of phospholipids and neutral lipids in mice brains was examined after intracerebral injection of [1-14C] arachidonic acid or [1-14C]palmitic acid. Electroconvulsive shock reduced greatly the removal of radiolabeled arachidonic acid from the free fatty acid pool. At the same time, the incorporation of arachidonic acid was partially inhibited in triacylglycerol, diacylglycerol, and phosphatidylinositol, whereas the incorporation of [1-14C]palmitic acid was not affected. Pretreatment with desipramine and pargyline potentiated the lipid effect of electroconvulsive shock in neutral glycerides. These electroconvulsive shock-induced changes reflect alterations in the metabolism of intracerebrally injected arachidonic acid, but not of similarly injected palmitic acid. From the available data whether decreased ATP, enzyme inhibition or other factors are involved cannot be ascertained. Moreover, the electroconvulsive shock-enhanced endogenous free arachidonic acid may possibly dilute the injected radiolabeled fatty acid, thus decreasing its availability for arachidonoyl-coenzyme A synthesis. Hence, a partial inhibition of the activation-acylation of these fatty acids, primarily arachidonic acid, also may be involved in the seizure-induced accumulation of free fatty acids in the brain.

Animals↗
PubMed1995

Regulation of FFA by the acyltransferase pathway in focal cerebral ischemia-reperfusion.

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 decrease in ATP, both during the ischemia period and at later time periods after reperfusion. In this study, the focal cerebral ischemia model was used to examine incorporation of [14C]arachidonic acid into the glycerolipids in rat MCA cortex at different reperfusion times after a 60 min ischemia. The label was injected intracerebrally into left and right MCA cortex 1 hr prior to decapitation. Labeled arachidonic acid was incorporated into phosphatidylcholine, phosphatidylethanolamine and neutral glycerides. With increasing time (4-16 hr) after a 60 min ischemia, an inhibition of labeled arachidonate uptake could be found in the right ischemic MCA cortex, whereas the distribution of radioactivity among the major phospholipids was not altered. When compared to labeled PC, there was a 3-4 fold increase in incorporation of label into phosphatidic acid and triacylglycerols (TG) in the right MCA cortex, suggesting of an increase in de novo biosynthesis of TG. In an in vitro assay system, synaptosomal membranes isolated from MCA cortex 8 and 16 hr after a 60 min ischemia showed a significant decrease in arachidonoyl transfer to lysophospholipids, due mainly to a decrease in lysophospholipid:acylCoA acyltransferase activity. Assay of phospholipase A2 activity with both syaptosomes and cytosol, however, did not show differences between left and right MCA cortex or with time after reperfusion. These results suggest that besides ATP availability, the decrease in acyltransferase activity may also contribute to the increase in FFA in cerebral ischemia-reperfusion.

1-Acylglycerophosphocholine O-Acyltransferase↗
PubMed1979

Determination of dimeric glycerol in monoglycerides by HPLC.

New regulations limit the amount of diglycerol that may be present in partial glycerides used as food emulsifiers. Dimeric glycerol can be easily determined by HPLC on silica columns using acetonitrile: water partition and RI detection. Results for free diglycerol and total diglycerol obtained with a number of monoglyceride samples are given.

Chromatography, High Pressure Liquid↗
PubMed1975

Endogenous and postheparin monoglyceride hydrolase in plasma of patients with acute virus hepatitis.

Endogenous and postheparin monoglyceride hydrolase (MGH) was studied in 9 patients with acute virus hepatitis and in 25 normal subjects with the use of a new spectrophotometric method. During the 4 weeks of observation the patients had significantly higher endogenous and reduced postheparin MGH levels if compared with the controls (p smaller than 0.001). In the initial phase of hepatitis the alterations were more pronounced and the serum glyceride concentration was raised. The results show that MGM activities in plasma may be greatly influenced by the liver.

Alanine Transaminase↗
PubMed1980

Normal lipid composition of fibroblasts from a case of type II achondrogenesis.

Fibroblasts from a case of achondrogenesis type II and fibroblasts from a normal control donor were subcultivated in vitro in parallel. The lipid study on these cells showed similar total lipid content, free cholesterol level, phospholipid distribution and fatty acid patterns, while neutral glycerides were slightly more elevated in the control fibroblasts. The histological finding of Laxova et al. (1973) could not be confirmed.

Achondroplasia↗
PubMedDate not supplied

Substrate effects on mitochondrial function and tissue lipids in low-flow hypoxia of isolated perfused rat hearts.

A possible causal relationship between tissue FFA contents and the depression in mitochondrial oxidative phosphorylation in myocardial ischaemia has been suggested. To test this hypothesis, the effects of different substrates added to the perfusates of hypoxic, low-flow perfused hearts were examined on oxidative phosphorylation catalysed by mitochondria isolated from such tissue. In an additional series of experiments tissue neutral glyceride and FFA levels were analysed and correlated with changes in mitochondrial function. Mitochondria isolated from hearts with a high tissue FFA content exhibited the lowest ADP/O ratios, RCI and QO2 values. On the other hand, mitochondria isolated from hearts with reduced FFA contents, performed significantly better with respect to these parameters of mitochondrial function studied.

Animals↗
PubMed1975

Effects of structural variation in beta-monoglycerides and other lipids on ordering in synthetic membranes.

Studies of beta-monoglyceride multilayers were carried out using a variety of spin probes. Effects of variables such as chain length, unsaturation, and branching on organization of acyl chains in lipids of model membranes were assessed. In addition, effects of added cholesterol on membrane order were determined. Results indicated that pure beta-monolaurin yields highly ordered films, whereas, unsaturated glycerides such as beta-monoolein, beta-monolinolein, and analogous lecithins yield fluid films. Branched monoglycerides behaved similarly to beta-monoolein, suggesting that branching in acyl chains is an effective substitute for unsaturation in maintaining membrane integrity. Multilayers of beta-monoglycerides exhibited similar properties to those of more complex lipids such as phospholipids. beta-Monoglycerides, by virtue of the presence of a single acyl chain, provided a relatively simple and effective alternative to the use of phospholipids in studies of membrane architecture.

Binding Sites↗