The Experts below are selected from a list of 666 Experts worldwide ranked by ideXlab platform
Roger S. Holmes - One of the best experts on this subject based on the ideXlab platform.
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Vertebrate patatin-like phospholipase domain-containing protein 4 (PNPLA4) genes and proteins: a gene with a role in Retinol metabolism
3 Biotech, 2012Co-Authors: Roger S. HolmesAbstract:At least eight families of mammalian patatin-like phospholipase domain-containing proteins (PNPLA) (E.C. 3.1.1.3) catalyse the hydrolysis of triglycerides, including PNPLA4 (alternatively PLPL4 or GS2), which also acts as a Retinol transacylase and participates in Retinol-Ester metabolism in the body. Bioinformatic methods were used to predict the amino acid sequences, secondary and tertiary structures and gene locations for PNPLA4 genes and encoded proteins using data from several vertebrate genome projects. PNPLA4 genes were located on the X-chromosome for the eutherian mammalian genomes examined. Opossum (marsupial), chicken, anole lizard, clawed toad, zebrafish and lancelet PNPLA4 genes were also identified. Most vertebrate PNPLA4 genes typically contained six coding exons whereas the lancelet PNPLA4 gene contained five coding exons. PNPLA4 subunits were the smallest among the PNPLA-like proteins examined containing 252–255 residues, shared >64 % sequence identities and key amino acid residues and predicted motifs, including ‘patatin’ (residues 6–176); putative catalytic dyad active site residues, Ser43 and Asp163; oxy-anion ‘hole’ residues (10–15); and conserved serine residues, which may perform structural roles for this enzyme. Predicted tertiary structures for PNPLA4 ‘patatin’ were similar to those reported for potato ‘patatin’, suggesting that it is strongly conserved during evolution. Human PNPLA4 contained a CpG49 island within the gene promoter, a miRNA-186 binding site within the mRNA 3′-noncoding region for the PNPLA4b isoform and exhibited wide tissue expression at a higher than average level. These and previous studies of vertebrate PNPLA -like gene families have suggested that PNPLA4 is an ancient gene in evolution which has resulted from a duplication of an ancestral invertebrate ATGL -like gene (encoding adipose triglyceride lipase).
Holmes Roger - One of the best experts on this subject based on the ideXlab platform.
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Vertebrate patatin-like phospholipase domain-containing protein 4 (PNPLA4) genes and proteins: a gene with a role in Retinol metabolism
Springer, 2012Co-Authors: Holmes RogerAbstract:At least eight families of mammalian patatin-like phospholipase domain-containing proteins (PNPLA) (E.C. 3.1.1.3) catalyse the hydrolysis of triglycerides, including PNPLA4 (alternatively PLPL4 or GS2), which also acts as a Retinol transacylase and participates in Retinol-Ester metabolism in the body. Bioinformatic methods were used to predict the amino acid sequences, secondary and tertiary structures and gene locations for PNPLA4 genes and encoded proteins using data from several vertebrate genome projects. PNPLA4 genes were located on the X-chromosome for the eutherian mammalian genomes examined. Opossum (marsupial), chicken, anole lizard, clawed toad, zebrafish and lancelet PNPLA4 genes were also identified. Most vertebrate PNPLA4 genes typically contained six coding exons whereas the lancelet PNPLA4 gene contained five coding exons. PNPLA4 subunits were the smallest among the PNPLA-like proteins examined containing 252-255 residues, shared >64 % sequence identities and key amino acid residues and predicted motifs, including 'patatin' (residues 6-176); putative catalytic dyad active site residues, Ser43 and Asp163; oxy-anion 'hole' residues (10-15); and conserved serine residues, which may perform structural roles for this enzyme. Predicted tertiary structures for PNPLA4 'patatin' were similar to those reported for potato 'patatin', suggesting that it is strongly conserved during evolution. Human PNPLA4 contained a CpG49 island within the gene promoter, a miRNA-186 binding site within the mRNA 3'-noncoding region for the PNPLA4b isoform and exhibited wide tissue expression at a higher than average level. These and previous studies of vertebrate PNPLA-like gene families have suggested that PNPLA4 is an ancient gene in evolution which has resulted from a duplication of an ancestral invertebrate ATGL-like gene (encoding adipose triglyceride lipase).Full Tex
María Dolores Tenorio - One of the best experts on this subject based on the ideXlab platform.
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Simultaneous determination of tocopherols, Retinol, Ester derivatives and β-carotene in milk- and soy-juice based beverages by HPLC with diode-array detection
LWT - Food Science and Technology, 2014Co-Authors: Víctor Andrés, María José Villanueva, María Dolores TenorioAbstract:Abstract A simple, sensitive and accurate HPLC method has been developed and validated for the simultaneous determination of α-tocopherol, γ-tocopherol, δ-tocopherol, α-tocopheryl acetate, retinyl palmitate, Retinol and β-carotene in milk- and soy-juice based beverages. The assay was performed using a Luna RP-C18 column with methanol: THF: water (67:27:6, v/v/v) as mobile phase, at a flow rate of 0.8 mL/min. Diode-array detector was set at 290 nm for tocopherols, 325 nm for Retinols and 440 nm for β-carotene. The method developed and validated is simple and shows good linearity, precision, accuracy and sensitivity and was applied to the analysis of different commercial mixed beverages. The profile of these compounds was different in milk- or soy-juice. Tocopheryl acetate and retinyl palmitate are added in all milk-juice and free γ- and δ-tocopherols are characteristic of soy-juice samples. β-carotene is present in both types of mixed beverages.
John J. Voorhees - One of the best experts on this subject based on the ideXlab platform.
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Extraction of Human Epidermis Treated with Retinol Yields Retro-Retinoids in Addition to Free Retinol and Retinyl Esters
Journal of Investigative Dermatology, 1996Co-Authors: Elizabeth A. Duell, Fadila Derguini, Sewon Kang, James T. Elder, John J. VoorheesAbstract:Vitamin A, all- trans -Retinol, is metabolized to retinoic acid in vivo by a tightly controlled two-step conversion. Retinoic acid then binds to nuclear receptors and modulates cellular proliferation and differentiation. Because only a small fraction of Retinol applied topically can be metabolized to retinoic acid, alternative pathways of Retinol metabolism in skin were investigated. Retinol (0.4%) was applied to adult human skin under occlusion for 6h to 4 d. The conversion of retinal into various metabolites such as 14-hydroxy-4,14- retro -Retinol, anhydroRetinol, 4-oxoRetinol, retinyl Esters, and retinyl glucuronides was investigated. The level of 14-hydroxy- retro -Retinol was increased from undetectable at time 0 to 326ng/g wet weight of tissue at 6h (6% of the Retinol level) and maintained approximately the same concentration at 24h to 409ng/g wet weight (1.9% of the Retinol level); it decreased to 48ng/g wet weight of tissue (12% of its maximum level) by 4 d. AnhydroRetinol was undetectable at time 0, increased only slightly at 6 h, and remained at the same level. We did not detect 4-oxoRetinol. Because 14-hydroxy- retro -Retinol was found in the Retinol-treated areas, its effects on epidermis were compared with those of Retinol. Topical application of trans -Retinol (0.3%) significantly increased both epidermal thickness and cellular retinoic acid binding protein II mRNA, whereas 14-hydroxy-4,14- retro -Retinol (0.3%) did not increase either of these well-characterized cutaneous retinoid responses. Retinol, when applied topically in pharmacologic doses to human epidermis, remained as free Retinol, was metabolized primarily to Retinol Ester, and was metabolized to a lesser extent to retro -retinoids and didehydroRetinol.
Víctor Andrés - One of the best experts on this subject based on the ideXlab platform.
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Simultaneous determination of tocopherols, Retinol, Ester derivatives and β-carotene in milk- and soy-juice based beverages by HPLC with diode-array detection
LWT - Food Science and Technology, 2014Co-Authors: Víctor Andrés, María José Villanueva, María Dolores TenorioAbstract:Abstract A simple, sensitive and accurate HPLC method has been developed and validated for the simultaneous determination of α-tocopherol, γ-tocopherol, δ-tocopherol, α-tocopheryl acetate, retinyl palmitate, Retinol and β-carotene in milk- and soy-juice based beverages. The assay was performed using a Luna RP-C18 column with methanol: THF: water (67:27:6, v/v/v) as mobile phase, at a flow rate of 0.8 mL/min. Diode-array detector was set at 290 nm for tocopherols, 325 nm for Retinols and 440 nm for β-carotene. The method developed and validated is simple and shows good linearity, precision, accuracy and sensitivity and was applied to the analysis of different commercial mixed beverages. The profile of these compounds was different in milk- or soy-juice. Tocopheryl acetate and retinyl palmitate are added in all milk-juice and free γ- and δ-tocopherols are characteristic of soy-juice samples. β-carotene is present in both types of mixed beverages.