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Mark Kester - One of the best experts on this subject based on the ideXlab platform.
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interleukin 1 induced ether linked Diglycerides inhibit calcium insensitive protein kinase c isotypes implications for growth senescence
Journal of Biological Chemistry, 1997Co-Authors: Atashi Mandal, Yizheng Wang, Paul Ernsberger, Mark KesterAbstract:It is hypothesized that inflammatory cytokines and vasoactive peptides stimulate distinct species of Diglycerides that differentially regulate protein kinase C isotypes. In published data, we demonstrated that interleukin-1, in contrast to endothelin, selectively generates ether-linked diglyceride species (alkyl, acyl- and alkenyl, acylglycerols) in rat mesangial cells, a smooth muscle-like pericyte in the glomerulus. We now demonstrate both in intact cell and in cell-free preparations that these interleukin-1 receptor-generated ether-linked Diglycerides inhibit immunoprecipitated protein kinase C delta and epsilon but not zeta activity. Neither interleukin-1 nor endothelin affect de novo protein expression of these protein kinase C isotypes. As down-regulation of calcium-insensitive protein kinase C isotypes has been linked to antimitogenic activity, we investigated growth arrest as a functional correlate for IL-1-generated ether-linked Diglycerides. Cell-permeable ether-linked Diglycerides mimic the effects of interleukin-1 to induce a growth-arrested state in both G-protein-linked receptor- and tyrosine kinase receptor-stimulated mesangial cells. This signaling mechanism implicates cytokine receptor-induced ether-linked Diglycerides as second messengers that inhibit the bioactivity of calcium-insensitive protein kinase C isotypes resulting in growth arrest.
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interleukin 1 and endothelin stimulate distinct species of Diglycerides that differentially regulate protein kinase c in mesangial cells
Journal of Biological Chemistry, 1995Co-Authors: Angela Musial, Atashi Mandal, E Coroneos, Mark KesterAbstract:Abstract Diglycerides are phospholipid-derived second messengers that serve as cofactors for protein kinase C activation. We have previously shown that, in rat glomerular mesangial cells, the cytokine, interleukin-1α, and the vasoactive peptide, endothelin, generate Diglycerides from unique phospholipid precursors. However, neither the molecular species of these Diglycerides nor their biological actions were determined. It is now hypothesized that interleukin-1- and endothelin-treated mesangial cells form distinct molecular species of Diglycerides which may serve different roles as intracellular signaling molecules. Diglyceride molecular species were resolved and quantified by TLC and high performance liquid chromatography as diglyceride-[C]acetate derivatives. Endothelin stimulates predominantly ester-linked species (diacylglycerols) in contrast to interleukin-1 which stimulates only ether-linked species (alkyl,acyl- and alkenyl,acylglycerols). In support of these data, interleukin-1-treated mesangial cells hydrolyze ethanolamine plasmalogens, vinyl ether-linked phospholipids. It has been reported that ether-linked, in contrast to ester-linked, diglyceride species do not activate protein kinase C activity. Thus, we next assessed membrane protein kinase C activity in endothelin- or interleukin-1-treated mesangial cells. Even though interleukin-1 has no effect upon basal protein kinase C activity, this cytokine, through the formation of ether-linked diglyceride second messengers, inhibits endothelin, platelet-activating factor, or arginine vasopressin-stimulated protein kinase C activity. We further demonstrate that ester-linked diacylglycerols but not alkyl,acyl- or alkenyl,acylglycerols substitute for phorbol esters in a cell-free protein kinase C assay. In addition, alkenyl,acylglycerols inhibit diacylglycerol-stimulated immunoprecipitated protein kinase C α activity in vitro and total protein kinase C activity in permeabilized mesangial cells ex vivo. Taken together, these data suggest that interleukin-1-induced formation of ether-linked Diglycerides may physiologically serve to down-regulate receptor-mediated protein kinase C activity and that individual molecular species of Diglycerides may serve different roles as intracellular signaling molecules.
Photis Dais - One of the best experts on this subject based on the ideXlab platform.
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classification of edible oils by employing 31p and 1h nmr spectroscopy in combination with multivariate statistical analysis a proposal for the detection of seed oil adulteration in virgin olive oils
Journal of Agricultural and Food Chemistry, 2003Co-Authors: Georgia Vigli, Angelos Philippidis, And Apostolos Spyros, Photis DaisAbstract:A combination of (1)H NMR and (31)P NMR spectroscopy and multivariate statistical analysis was used to classify 192 samples from 13 types of vegetable oils, namely, hazelnut, sunflower, corn, soybean, sesame, walnut, rapeseed, almond, palm, groundnut, safflower, coconut, and virgin olive oils from various regions of Greece. 1,2-Diglycerides, 1,3-Diglycerides, the ratio of 1,2-Diglycerides to total Diglycerides, acidity, iodine value, and fatty acid composition determined upon analysis of the respective (1)H NMR and (31)P NMR spectra were selected as variables to establish a classification/prediction model by employing discriminant analysis. This model, obtained from the training set of 128 samples, resulted in a significant discrimination among the different classes of oils, whereas 100% of correct validated assignments for 64 samples were obtained. Different artificial mixtures of olive-hazelnut, olive-corn, olive-sunflower, and olive-soybean oils were prepared and analyzed by (1)H NMR and (31)P NMR spectroscopy. Subsequent discriminant analysis of the data allowed detection of adulteration as low as 5% w/w, provided that fresh virgin olive oil samples were used, as reflected by their high 1,2-Diglycerides to total Diglycerides ratio (D > or = 0.90).
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determination of the diglyceride content in greek virgin olive oils and some commercial olive oils by employing 31 p nmr spectroscopy
Journal of Agricultural and Food Chemistry, 2002Co-Authors: Penelope Fronimaki, Apostolos Spyros, Stella Christophoridou, Photis DaisAbstract:In this study, the diglyceride contents of 96 samples of virgin olive oils from the regions of Crete, Lesvos, Messinia, Pilion, Zakynthos, Halkidiki, and Ilia, 15 samples of commercial extra virgin and pure olive oils, and 3 samples each of refined olive oils and pomace oils were determined by a facile method introduced in a previous publication. This method is based on the phosphitylation of the free hydroxyls of the Diglycerides with 2-chloro-4,4,5,5-tetramethyldioxaphospholane and the integration of the appropriate peaks in the (31)P NMR spectra. This preliminary study showed interesting trends in the diglyceride content of the virgin olive oils from the various regions of Greece that can be used as simple criteria to assess the olive oil characteristics. Analysis of variance has been carried out for the diglyceride content of each region in an attempt to detect possible differences in the diglyceride levels among the various regions. Finally, the relationship between the ratio of 1,2-Diglycerides to the total amount of Diglycerides and the total amount of Diglycerides has been used to monitor the quality of virgin olive oils, commercial olive oils, refined olive oils, and pomace oils.
Atashi Mandal - One of the best experts on this subject based on the ideXlab platform.
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interleukin 1 induced ether linked Diglycerides inhibit calcium insensitive protein kinase c isotypes implications for growth senescence
Journal of Biological Chemistry, 1997Co-Authors: Atashi Mandal, Yizheng Wang, Paul Ernsberger, Mark KesterAbstract:It is hypothesized that inflammatory cytokines and vasoactive peptides stimulate distinct species of Diglycerides that differentially regulate protein kinase C isotypes. In published data, we demonstrated that interleukin-1, in contrast to endothelin, selectively generates ether-linked diglyceride species (alkyl, acyl- and alkenyl, acylglycerols) in rat mesangial cells, a smooth muscle-like pericyte in the glomerulus. We now demonstrate both in intact cell and in cell-free preparations that these interleukin-1 receptor-generated ether-linked Diglycerides inhibit immunoprecipitated protein kinase C delta and epsilon but not zeta activity. Neither interleukin-1 nor endothelin affect de novo protein expression of these protein kinase C isotypes. As down-regulation of calcium-insensitive protein kinase C isotypes has been linked to antimitogenic activity, we investigated growth arrest as a functional correlate for IL-1-generated ether-linked Diglycerides. Cell-permeable ether-linked Diglycerides mimic the effects of interleukin-1 to induce a growth-arrested state in both G-protein-linked receptor- and tyrosine kinase receptor-stimulated mesangial cells. This signaling mechanism implicates cytokine receptor-induced ether-linked Diglycerides as second messengers that inhibit the bioactivity of calcium-insensitive protein kinase C isotypes resulting in growth arrest.
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interleukin 1 and endothelin stimulate distinct species of Diglycerides that differentially regulate protein kinase c in mesangial cells
Journal of Biological Chemistry, 1995Co-Authors: Angela Musial, Atashi Mandal, E Coroneos, Mark KesterAbstract:Abstract Diglycerides are phospholipid-derived second messengers that serve as cofactors for protein kinase C activation. We have previously shown that, in rat glomerular mesangial cells, the cytokine, interleukin-1α, and the vasoactive peptide, endothelin, generate Diglycerides from unique phospholipid precursors. However, neither the molecular species of these Diglycerides nor their biological actions were determined. It is now hypothesized that interleukin-1- and endothelin-treated mesangial cells form distinct molecular species of Diglycerides which may serve different roles as intracellular signaling molecules. Diglyceride molecular species were resolved and quantified by TLC and high performance liquid chromatography as diglyceride-[C]acetate derivatives. Endothelin stimulates predominantly ester-linked species (diacylglycerols) in contrast to interleukin-1 which stimulates only ether-linked species (alkyl,acyl- and alkenyl,acylglycerols). In support of these data, interleukin-1-treated mesangial cells hydrolyze ethanolamine plasmalogens, vinyl ether-linked phospholipids. It has been reported that ether-linked, in contrast to ester-linked, diglyceride species do not activate protein kinase C activity. Thus, we next assessed membrane protein kinase C activity in endothelin- or interleukin-1-treated mesangial cells. Even though interleukin-1 has no effect upon basal protein kinase C activity, this cytokine, through the formation of ether-linked diglyceride second messengers, inhibits endothelin, platelet-activating factor, or arginine vasopressin-stimulated protein kinase C activity. We further demonstrate that ester-linked diacylglycerols but not alkyl,acyl- or alkenyl,acylglycerols substitute for phorbol esters in a cell-free protein kinase C assay. In addition, alkenyl,acylglycerols inhibit diacylglycerol-stimulated immunoprecipitated protein kinase C α activity in vitro and total protein kinase C activity in permeabilized mesangial cells ex vivo. Taken together, these data suggest that interleukin-1-induced formation of ether-linked Diglycerides may physiologically serve to down-regulate receptor-mediated protein kinase C activity and that individual molecular species of Diglycerides may serve different roles as intracellular signaling molecules.
Angela Musial - One of the best experts on this subject based on the ideXlab platform.
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interleukin 1 and endothelin stimulate distinct species of Diglycerides that differentially regulate protein kinase c in mesangial cells
Journal of Biological Chemistry, 1995Co-Authors: Angela Musial, Atashi Mandal, E Coroneos, Mark KesterAbstract:Abstract Diglycerides are phospholipid-derived second messengers that serve as cofactors for protein kinase C activation. We have previously shown that, in rat glomerular mesangial cells, the cytokine, interleukin-1α, and the vasoactive peptide, endothelin, generate Diglycerides from unique phospholipid precursors. However, neither the molecular species of these Diglycerides nor their biological actions were determined. It is now hypothesized that interleukin-1- and endothelin-treated mesangial cells form distinct molecular species of Diglycerides which may serve different roles as intracellular signaling molecules. Diglyceride molecular species were resolved and quantified by TLC and high performance liquid chromatography as diglyceride-[C]acetate derivatives. Endothelin stimulates predominantly ester-linked species (diacylglycerols) in contrast to interleukin-1 which stimulates only ether-linked species (alkyl,acyl- and alkenyl,acylglycerols). In support of these data, interleukin-1-treated mesangial cells hydrolyze ethanolamine plasmalogens, vinyl ether-linked phospholipids. It has been reported that ether-linked, in contrast to ester-linked, diglyceride species do not activate protein kinase C activity. Thus, we next assessed membrane protein kinase C activity in endothelin- or interleukin-1-treated mesangial cells. Even though interleukin-1 has no effect upon basal protein kinase C activity, this cytokine, through the formation of ether-linked diglyceride second messengers, inhibits endothelin, platelet-activating factor, or arginine vasopressin-stimulated protein kinase C activity. We further demonstrate that ester-linked diacylglycerols but not alkyl,acyl- or alkenyl,acylglycerols substitute for phorbol esters in a cell-free protein kinase C assay. In addition, alkenyl,acylglycerols inhibit diacylglycerol-stimulated immunoprecipitated protein kinase C α activity in vitro and total protein kinase C activity in permeabilized mesangial cells ex vivo. Taken together, these data suggest that interleukin-1-induced formation of ether-linked Diglycerides may physiologically serve to down-regulate receptor-mediated protein kinase C activity and that individual molecular species of Diglycerides may serve different roles as intracellular signaling molecules.
J.i. Di Cosimo - One of the best experts on this subject based on the ideXlab platform.
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Diglyceride-rich oils from glycerolysis of edible vegetable oils
Catalysis Today, 2018Co-Authors: Cristián Alejandro Ferretti, M.l. Spotti, J.i. Di CosimoAbstract:Abstract The human metabolism of 1,3-diglyceride is believed to occur through a pathway that avoids re-synthesis of triglycerides and the consequent fat deposit in the body tissues. The synthesis of healthy vegetable oils with reduced triglyceride content was investigated using food production-compatible MgO as basic catalyst. The partial conversion of the triglycerides present in commercial edible oils into Diglycerides was carried out by glycerolysis. After optimizing the reaction conditions such as temperature, glycerol/triglyceride ratio, and inert gas flow rate, triglyceride conversions of up to 70% were reached after 8 h as well as a product containing 54% of Diglycerides, 67% of which is the healthier 1,3-isomer.