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Biochimica Et Biophysica Acta Sep 1984The percent distributions of the molecular species of diacylglycerol, phosphatidylcholine and phosphatidylethanolamine in rat whole lung and type II pneumocytes were...
A study of the molecular species of diacylglycerol, phosphatidylcholine and phosphatidylethanolamine and of cholinephosphotransferase and ethanolaminephosphotransferase activities in the type II pneumocyte.
The percent distributions of the molecular species of diacylglycerol, phosphatidylcholine and phosphatidylethanolamine in rat whole lung and type II pneumocytes were found to differ significantly. Diacylglycerol from the type II pneumocyte is enriched in the disaturated species and diminished in the polyenoic species compared to whole lung. Type II pneumocyte phosphatidylcholine is enriched in the disaturated species and diminished in all other species compared to whole lung. Relative to whole lung, type II pneumocyte phosphatidylethanolamine is greatly enriched in monoenoic and depleted in polyenoic fatty acid species. Analysis of the fatty acid composition of the molecular species in general indicated differences in relative amounts of fatty acids which were most pronounced in palmitic, palmitoleic, stearic and oleic acids, both within and between type II pneumocyte and whole lung glycerolipids. Significant differences between molecular species also existed within type II pneumocyte glycerolipids. In this cell type, phosphatidylcholine is enriched in disaturated and diminished in monoenoic species compared to diacylglycerol. Phosphatidylethanolamine is enriched in monoenoic and polyenoic species relative to diacylglycerol. In order to determine whether differences observed in type II pneumocyte glycerolipid molecular species were attributable to differences in the specificities of cholinephosphotransferase and ethanolaminephosphotransferase, the selectivity of these enzymes was examined. While cholinephosphotransferase showed diminished activity towards 1-stearoyl-2-linoleoyl-sn-glycerol, neither enzyme showed selectivity towards other tested diacylglycerols under a variety of conditions. Therefore, while in the type II pneumocyte significant amounts of phosphatidylcholine (particularly the disaturated species) and phosphatidylethanolamine may be synthesized de novo, enzymes responsible for remodeling (phospholipase A2 and acyltransferases) may play an important role in establishing the final molecular species composition of both phosphatidylcholine and phosphatidylethanolamine.
Topics: Animals; Diacylglycerol Cholinephosphotransferase; Diglycerides; Ethanolaminephosphotransferase; Glycerides; Lung; Male; Phosphatidylcholines; Phosphatidylethanolamines; Phosphotransferases; Rats; Rats, Inbred Strains
PubMed: 6089898
DOI: 10.1016/0005-2760(84)90072-9 -
Diabetes Jun 1990An increase in glucose concentration in the medium from 5 to 30 mM transiently enhanced diacylglycerol mass and activated protein kinase C in glomeruli isolated from...
An increase in glucose concentration in the medium from 5 to 30 mM transiently enhanced diacylglycerol mass and activated protein kinase C in glomeruli isolated from nondiabetic rats as assessed by translocation of enzyme activity from the soluble to particulate fraction. Effects of glucose on both diacylglycerol mass and protein kinase C were evident at 5 and 15 min but waned by 30 min. An increase in glucose concentration in the medium also increased the incorporation of [14C]glucose into the glycerol backbone of diacylglycerol, triacylglycerol, and phospholipids. Several observations implied that [14C]glucose was being incorporated into diacylglycerol through the de novo pathway for glycerolipid synthesis rather than being derived from phospholipids. 1) [14C]glucose incorporation into all the lipids was suppressed by 2-deoxyglucose. 2) The incorporation of [14C]glucose into diacylglycerol and triacylglycerol was evident by 1 min and increased linearly for at least 30 min. In contrast, incorporation into phosphatidylcholine occurred with a lag of at least 5 min. 3) Although only 10% of the [14C]glucose incorporated into lipids was present in diacylglycerol versus greater than 50% in phospholipids, the specific activity of [14C]glucose in diacylglycerol was fivefold higher than that in phospholipid when expressed as a function of mass. 4) Glucose had no effect on labeled diacylglycerol or phosphatidic acid production in glomeruli that had been prelabeled with [3H]glycerol. Glucose-induced increases in diacylglycerol may contribute to the activation of glomerular protein kinase C observed in early diabetes.
Topics: Animals; Culture Media; Deoxyglucose; Diglycerides; Dose-Response Relationship, Drug; Female; Glucose; Glycerides; In Vitro Techniques; Kidney Glomerulus; Lipids; Phospholipids; Protein Kinase C; Rats; Rats, Inbred Strains; Time Factors
PubMed: 2347431
DOI: 10.2337/diab.39.6.667 -
Journal of Lipid Research Jun 2000alpha-Cyclodextrins are water-soluble cyclic hexamers of glucose units with hydrophobic cavities capable of solubilizing lipophiles. Incubating alpha-cyclodextrin with...
alpha-Cyclodextrins are water-soluble cyclic hexamers of glucose units with hydrophobic cavities capable of solubilizing lipophiles. Incubating alpha-cyclodextrin with high density lipophorin from Manduca sexta or Bombyx mori resulted in a cloudy, turbid solution. Centrifugation separated a pale yellowish precipitate. Thin-layer chromatography analysis of the lipid extract of the precipitate showed that the major lipid was diacylglycerol, while KBr density gradient analysis of the supernatant demonstrated the presence of a lipid-depleted very high density lipophorin. Transfer of diacylglycerol from lipophorin to cyclodextrin was specific to alpha-cyclodextrin and was not observed with beta- or gamma-cyclodextrins. pH had no effect on diacylglycerol transfer to alpha-cyclodextrin. However, the transfer was strongly dependent on the concentration of alpha-cyclodextrin and temperature. Increasing the concentration of alpha-cyclodextrin in the incubation mixture was associated with the formation of increasingly higher density lipophorins. Thus, at 20, 30, and 40 mm alpha-cyclodextrin, the density of B. mori lipophorin increased from 1.107 g/ml to 1.123, 1. 148, and 1.181 g/ml, respectively. At concentrations greater than 40 mm, alpha-cyclodextrin had no further effect on the density of lipophorin. alpha-Cyclodextrin removed at most 83;-87% of the diacylglycerol present in lipophorin. Temperature played an important role in altering the amount of diacylglycerols transferred to alpha-cyclodextrin. At 30 mm alpha-cyclodextrin, the amount of diacylglycerol transferred at different temperatures was 50% at 4 degrees C, 41% at 15 degrees C, 20% at 28 degrees C, and less than 3% at 37 degrees C. We propose that diacylglycerol transfers to alpha-cyclodextrin via an aqueous diffusion pathway and that the driving force for the transfer is the formation of an insoluble alpha-cyclodextrin-diacylglycerol complex.
Topics: Animals; Carrier Proteins; Cyclodextrins; Diglycerides; Hydrogen-Ion Concentration; Insecta; Lipoproteins; Lipoproteins, HDL; Temperature; alpha-Cyclodextrins
PubMed: 10828085
DOI: No ID Found -
Photodermatology, Photoimmunology &... Apr 1991We investigated the effect of topically applied diacylglycerols (DG) on melanogenesis in Skh-2 pigmented hairless mouse skin. Groups of mice were treated according to 4...
We investigated the effect of topically applied diacylglycerols (DG) on melanogenesis in Skh-2 pigmented hairless mouse skin. Groups of mice were treated according to 4 different regimens of either 1,2-dioctanoyl-sn-glycerol (DOG) or 1-oleyl-2-acetyl-sn-glycerol (OAG) with or without ultraviolet irradiation (UVR). After the treatment regimens were completed, separated epidermal tissue was stained with L-dopa and thin sections of whole skin were stained by the Warthin-Starry method to detect melanin deposition. Quantification of the stained areas by digital image analysis disclosed that DOG treatment without UVR increased the dopa-positive area in skin in a dose-dependent manner but had no effect on melanin deposition. DG treatment acted synergistically with UVR to enhance melanogenesis, with synergism being more pronounced for melanin deposition than for dopa staining. DOG treatment prior to UVR also resulted in an enhanced melanogenic response to UVR, suggesting that DG increases the sensitivity of melanocytes to subsequent UVR by inducing dopa oxidase activity. OAG also enhanced UVR-induced melanogenesis in a dose-dependent manner and was at least as potent an inducer as was DOG. Because DG is known to activate protein kinase C, our results suggest that a protein kinase C-dependent process is involved in melanogenesis.
Topics: Administration, Cutaneous; Animals; Diglycerides; Dihydroxyphenylalanine; Dose-Response Relationship, Drug; Drug Synergism; Female; Melanins; Melanocytes; Mice; Mice, Hairless; Skin; Ultraviolet Rays
PubMed: 1756112
DOI: No ID Found -
Membrane-surface anchoring of charged diacylglycerol-lactones correlates with biological activities.Chembiochem : a European Journal of... Sep 2010Synthetic diacylglycerol-lactones (DAG-lactones) are effective modulators of critical cellular signaling pathways, downstream of the lipophilic second messenger...
Synthetic diacylglycerol-lactones (DAG-lactones) are effective modulators of critical cellular signaling pathways, downstream of the lipophilic second messenger diacylglycerol, that activate a host of protein kinase C (PKC) isozymes and other nonkinase proteins that share similar C1 membrane-targeting domains with PKC. A fundamental determinant of the biological activity of these amphiphilic molecules is the nature of their interactions with cellular membranes. This study examines the biological properties of charged DAG-lactones exhibiting different alkyl groups attached to the heterocyclic nitrogen of an α-pyridylalkylidene chain, and particularly the relationship between membrane interactions of the substituted DAG-lactones and their respective biological activities. Our results suggest that bilayer interface localization of the N-alkyl chain in the R(2) position of the DAG-lactones inhibits translocation of PKC isoenzymes onto the cellular membrane. However, the orientation of a branched alkyl chain at the bilayer surface facilitates PKC binding and translocation. This investigation emphasizes that bilayer localization of the aromatic side residues of positively charged DAG-lactone derivatives play a central role in determining biological activity, and that this factor contributes to the diversity of biological actions of these synthetic biomimetic ligands.
Topics: Animals; Calorimetry, Differential Scanning; Cell Line; Cell Membrane; Diglycerides; Lactones; Models, Molecular; Protein Kinase C; Rats
PubMed: 20715268
DOI: 10.1002/cbic.201000343 -
Lipids Feb 2009Diacylglycerol (DAG) supplementation has been shown to be associated with the reduction of postprandial triacylglycerol (TAG) concentration, although the extent of the... (Meta-Analysis)
Meta-Analysis Randomized Controlled Trial
Diacylglycerol (DAG) supplementation has been shown to be associated with the reduction of postprandial triacylglycerol (TAG) concentration, although the extent of the association is uncertain. We quantitatively examined the effect of dietary DAG on postprandial serum TAG concentration by conducting a meta-analysis of randomized controlled trials. Potential papers were initially searched for in the electronic databases of Medline, Embase and Cochrane library. Inclusion criteria required the trial to be randomized with DAG as the treatment group, and TAG as the control group. Information was extracted independently by two investigators and the effect of DAG on postprandial TAG concentration was examined in Review Manager 4.2. Seven papers were included in the statistic pooling. DAG supplementation reduced the increment of postprandial TAG concentration significantly at postprandial 2 h (Weighted mean difference (WMD) -0.07 mmol/L; 95% CI -0.13 to 0.00 mmol/L; P = 0.05), 4 h (WMD -0.15 mmol/L; 95% CI -0.24 to -0.06 mmol/L; P = 0.002) and 6 h (WMD -0.14 mmol/L; 95% CI -0.23 to -0.05 mmol/L; P = 0.002). Linear regression showed that the effect of DAG was positively correlated with the daily dosage at 2 h (P = 0.095) and 6 h (P = 0.053) after lipid loading. In conclusion, compared with TAG oil, DAG reduced the postprandial serum TAG concentration at 2 h, 4 h and 6 h postprandial and was positively correlated with daily dosage.
Topics: Adult; Diglycerides; Female; Humans; Male; Middle Aged; Postprandial Period; Time Factors; Triglycerides
PubMed: 18989717
DOI: 10.1007/s11745-008-3258-2 -
Food Chemistry Jul 2021Oleofoams have emerged as attractive low-calorie aeration systems, but saturated lipids or large amount of surfactants are commonly required. Herein, an innovative...
Oleofoams have emerged as attractive low-calorie aeration systems, but saturated lipids or large amount of surfactants are commonly required. Herein, an innovative strategy was proposed to create oleofoams using medium-long chain diacylglycerol (MLCD) and β-sitosterol (St). The oleofoams prepared using MLCD and St in ratios of 15:5 and 12:8 exhibited smaller bubble size and much higher stability. MLCD crystals formed rigid Pickering shell, whereby air bubbles acted as "active fillers" leading to enhanced rigidity. Both Pickering and network stabilization for the MLCD-St oleofoam provided a steric hindrance against coalescence. The gelators interacted via hydrogen bonding, causing a condensing effect in improving the gel elasticity. The oleofoams and foam-based emulsions exhibited a favorable capacity in controlling volatile release where the maximum headspace concentrations and partition coefficients showed a significantly decrease. Overall, the oleofoams have shown great potential for development of low-calorie foods and delivery systems with enhanced textural and nutritional features.
Topics: Diglycerides; Hydrogen Bonding; Sitosterols; Surface-Active Agents
PubMed: 33601090
DOI: 10.1016/j.foodchem.2021.129275 -
Journal of Applied Physiology... Sep 2012One of the fundamental biochemical defects underlying the complications of diabetic cardiovascular system is elevation of diacylglycerol (DAG) and its effects on protein...
One of the fundamental biochemical defects underlying the complications of diabetic cardiovascular system is elevation of diacylglycerol (DAG) and its effects on protein kinase C (PKC) signaling. It has been noted that exercise training attenuates poor cardiac performance in Type 1 diabetes. However, the role of PKC signaling in exercise-induced alleviation of cardiac abnormalities in diabetes is not clear. We investigated the possibility that exercise training modulates PKC-βII signaling to elicit its beneficial effects on the diabetic heart. bio-breeding diabetic resistant rats, a model reminiscent of Type 1 diabetes in humans, were randomly assigned to four groups: 1) nonexercised nondiabetic (NN); 2) nonexercised diabetic (ND); 3) exercised nondiabetic; and 4) exercised diabetic. Treadmill training was initiated upon the onset of diabetes. At the end of 8 wk, left ventricular (LV) hemodynamic assessment revealed compromised function in ND compared with the NN group. LV myocardial histology revealed increased collagen deposition in ND compared with the NN group, while electron microscopy showed a reduction in the viable mitochondrial fraction. Although the PKC-βII levels and activity were unchanged in the diabetic heart, the DAG levels were increased. With exercise training, the deterioration of LV structure and function in diabetes was attenuated. Notably, improved cardiac performance in training was associated with a decrease in myocardial DAG levels in diabetes. Exercise-induced benefits on cardiac performance in diabetes may be mediated by prevention of an increase in myocardial DAG levels.
Topics: Amino Acid Sequence; Animals; Diabetes Mellitus, Type 1; Diglycerides; Male; Molecular Sequence Data; Myocardium; Physical Conditioning, Animal; Protein Kinase C; Protein Kinase C beta; Random Allocation; Rats; Ventricular Function, Left
PubMed: 22797313
DOI: 10.1152/japplphysiol.01626.2011 -
Autophagy Mar 2011Antibacterial autophagy is understood to be a key cellular immune response to invading microbes. However, the mechanism(s) by which bacteria are selected as targets of...
Antibacterial autophagy is understood to be a key cellular immune response to invading microbes. However, the mechanism(s) by which bacteria are selected as targets of autophagy remain unclear. We recently identified diacylglycerol as a novel signaling molecule that targets bacteria to the autophagy pathway, and show that it acts via protein kinase C activation. We also found that Pkc1 is required for autophagy in yeast, indicating that this kinase plays a conserved role in autophagy regulation.
Topics: Autophagy; Bacteria; Diglycerides; Models, Biological; Salmonella typhimurium
PubMed: 21079417
DOI: 10.4161/auto.7.3.14045 -
The Journal of Biological Chemistry Mar 1990A detailed structure/function analysis of the substrate specificity of Escherichia coli sn-1,2-diacylglycerol kinase was performed with three goals in mind: (a) to... (Comparative Study)
Comparative Study
A detailed structure/function analysis of the substrate specificity of Escherichia coli sn-1,2-diacylglycerol kinase was performed with three goals in mind: (a) to define the substrate specificity; (b) to discover inhibitors; and (c) to elucidate the specificity of diacylglycerol-dependent inactivation. Forty-seven structural analogues of sn-1,2-diacylglycerol were prepared and examined as substrates, inhibitors, and irreversible inactivators of the enzyme using mixed micellar assay methods. Modification of the acyl chains or the sn-2 ester affected the apparent Km but had only small effects on Vm; modifications of the sn-1 ester, sn-3 methylene, or sn-3 hydroxyl had large effects on the apparent Vm and smaller effects on Km. Consistent with these observations, diacylglycerol analogues modified only in the acyl chains or sn-2 ester were not diacylglycerol kinase inhibitors, whereas analogues with substitutions of the sn-1 ester or sn-3 hydroxyl frequently caused inhibition. A hydrogen bond-donating group was required for an analogue to be a diacylglycerol kinase inhibitor. Studies of diacylglycerol kinase inactivation by the various analogues were consistent with the previous conclusion that this process involves an interaction of diacylglycerols with an enzyme conformation different from that active in catalysis (Walsh, J. P., and Bell, R. M. (1986) J. Biol. Chem. 261, 15062-15069). Studies with a water-soluble diacylglycerol, sn-1,2-dibutyrylglycerol, allowed direct comparison of diacylglycerol kinase activity in mixed micelles with that in native membranes. The results are discussed in relation to the structural requirements of other diacylglycerol-dependent enzymes.
Topics: Diacylglycerol Kinase; Diglycerides; Enzyme Activation; Escherichia coli; Glycerides; Hydrogen Bonding; Kinetics; Lipids; Molecular Structure; Phosphotransferases; Protein Conformation; Structure-Activity Relationship; Substrate Specificity
PubMed: 2155227
DOI: No ID Found