The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Carl E Cerniglia - One of the best experts on this subject based on the ideXlab platform.
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enzymatic mechanisms involved in Phenanthrene degradation by the white rot fungus pleurotus ostreatus
Applied and Environmental Microbiology, 1997Co-Authors: L Bezalel, Yitzhak Hadar, Carl E CernigliaAbstract:The enzymatic mechanisms involved in the degradation of Phenanthrene by the white rot fungus Pleurotus ostreatus were examined. Phase I metabolism (cytochrome P-450 monooxygenase and epoxide hydrolase) and phase II conjugation (glutathione S-transferase, aryl sulfotransferase, UDP-glucuronosyltransferase, and UDP-glucosyltransferase) enzyme activities were determined for mycelial extracts of P. ostreatus. Cytochrome P-450 was detected in both cytosolic and microsomal fractions at 0.16 and 0.38 nmol min(sup-1) mg of protein(sup1), respectively. Both fractions oxidized [9,10-(sup14)C]Phenanthrene to Phenanthrene trans-9,10-dihydrodiol. The cytochrome P-450 inhibitors 1-aminobenzotriazole (0.1 mM), SKF-525A (proadifen, 0.1 mM), and carbon monoxide inhibited the cytosolic and microsomal P-450s differently. Cytosolic and microsomal epoxide hydrolase activities, with Phenanthrene 9,10-oxide as the substrate, were similar, with specific activities of 0.50 and 0.41 nmol min(sup-1) mg of protein(sup-1), respectively. The epoxide hydrolase inhibitor cyclohexene oxide (5 mM) significantly inhibited the formation of Phenanthrene trans-9,10-dihydrodiol in both fractions. The phase II enzyme 1-chloro-2,4-dinitrobenzene glutathione S-transferase was detected in the cytosolic fraction (4.16 nmol min(sup-1) mg of protein(sup-1)), whereas aryl adenosine-3(prm1)-phosphate-5(prm1)-phosphosulfate sulfotransferase (aryl PAPS sulfotransferase) UDP-glucuronosyltransferase, and UDP-glucosyltransferase had microsomal activities of 2.14, 4.25, and 4.21 nmol min(sup-1) mg of protein(sup-1), respectively, with low activity in the cytosolic fraction. However, when P. ostreatus culture broth incubated with Phenanthrene was screened for phase II metabolites, no sulfate, glutathione, glucoside, or glucuronide conjugates of Phenanthrene metabolites were detected. These experiments indicate the involvement of cytochrome P-450 monooxygenase and epoxide hydrolase in the initial phase I oxidation of Phenanthrene to form Phenanthrene trans-9,10-dihydrodiol. Laccase and manganese-independent peroxidase were not involved in the initial oxidation of Phenanthrene. Although P. ostreatus had phase II xenobiotic metabolizing enzymes, conjugation reactions were not important for the elimination of hydroxylated Phenanthrene.
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metabolism of Phenanthrene by the white rot fungus pleurotus ostreatus
Applied and Environmental Microbiology, 1996Co-Authors: L Bezalel, Yitzhak Hadar, Peter P Fu, James P Freeman, Carl E CernigliaAbstract:The white rot fungus Pleurotus ostreatus, grown for 11 days in basidiomycetes rich medium containing [14C] Phenanthrene, metabolized 94% of the Phenanthrene added. Of the total radioactivity, 3% was oxidized to CO2. Approximately 52% of Phenanthrene was metabolized to trans-9,10-dihydroxy-9,10-dihydroPhenanthrene (Phenanthrene trans-9,10-dihydrodiol) (28%), 2,2'-diphenic acid (17%), and unidentified metabolites (7%). Nonextractable metabolites accounted for 35% of the total radioactivity. The metabolites were extracted with ethyl acetate, separated by reversed-phase high-performance liquid chromatography, and characterized by 1H nuclear magnetic resonance, mass spectrometry, and UV spectroscopy analyses. 18O2-labeling experiments indicated that one atom of oxygen was incorporated into the Phenanthrene trans-9,10-dihydrodiol. Circular dichroism spectra of the Phenanthrene trans-9,10-dihydrodiol indicated that the absolute configuration of the predominant enantiomer was 9R,10R, which is different from that of the principal enantiomer produced by Phanerochaete chrysosporium. Significantly less Phenanthrene trans-9,10-dihydrodiol was observed in incubations with the cytochrome P-450 inhibitor SKF 525-A (77% decrease), 1-aminobenzotriazole (83% decrease), or fluoxetine (63% decrease). These experiments with cytochrome P-450 inhibitors and 18O2 labeling and the formation of Phenanthrene trans-9R,10R-dihydrodiol as the predominant metabolite suggest that P. ostreatus initially oxidizes Phenanthrene stereoselectively by a cytochrome P-450 monoxygenase and that this is followed by epoxide hydrolase-catalyzed hydration reactions.
Suidong Wang - One of the best experts on this subject based on the ideXlab platform.
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saturated deep blue emitter based on a spiro benzoanthracene fluorene linked Phenanthrene derivative for non doped organic light emitting diodes
New Journal of Chemistry, 2014Co-Authors: Houjie Liang, Xinxin Wang, Xingye Zhang, Zhiyang Liu, Xinhua Ouyang, Suidong WangAbstract:A spiro[benzoanthracene–fluorene] derivative containing a Phenanthrene moiety, 2′,3-di(phenanthren-9-yl)spiro[benzo[de]anthracene-7,9′-fluorene] (DPSBAF), was prepared by a Suzuki coupling reaction. The photophysical and photochemical properties were investigated systematically. A non-doped organic light-emitting diode using DPSBAF as the emitter achieved a luminance efficiency of 2.18 cd A−1 with Commission Internationale de l'Eclairage 1931 chromaticity coordinates of (0.15, 0.09). The synthesized spiro[benzoanthracene–fluorene] derivative with a high thermal stability, a glass transition temperature of 210 °C and a decomposition temperature of 410 °C, shows potential for application in non-doped saturated deep-blue organic light-emitting diodes.
Peter V. Hodson - One of the best experts on this subject based on the ideXlab platform.
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measuring the toxicity of alkyl Phenanthrenes to early life stages of medaka oryzias latipes using partition controlled delivery
Environmental Toxicology and Chemistry, 2011Co-Authors: Dominique Turcotte, Michelle Bowerman, Yiannis Kiparissis, Stephen R Brown, Parveen Akhtar, Peter V. HodsonAbstract:Alkyl-Phenanthrenes are a class of compounds present in crude oil and toxic to developing fish. Most research on alkyl-Phenanthrenes has focused on retene (7-isopropyl-1-methyl-Phenanthrene), but little is known about the chronic toxicity of related congeners to the early life stages of fish. This project is the first to describe the chronic toxicity of a series of alkyl-Phenanthrenes to the embryos of Japanese medaka (Oryzias latipes) using the partition-controlled delivery (PCD) method of exposure and is the first to establish a relationship between toxicity of alkyl-Phenanthrenes and log P. With PCD, test concentrations were maintained by equilibrium partitioning of test chemicals from polydimethylsiloxane (PDMS) films containing various concentrations of C1 to C4 Phenanthrenes. Log film:solution partition constants (log Kfs) and aqueous solubility limits were determined for each alkyl-Phenanthrene. The prevalence of abnormalities in fish embryos increased in an exposure-dependent manner, with median effective concentration (EC50) values lower than experimental solubility limits of the compounds, and typical of environmental concentrations. Alkyl-Phenanthrenes were more toxic to medaka embryos than unsubstituted Phenanthrene, with effects resembling those of dioxin and indicating a specific receptor-based mechanism of toxicity. These results extend conclusions for the Exxon Valdez oil spill, suggest a specific mechanism of toxicity for alkyl-Phenanthrenes, and provide a model for assessing the risks of mixture toxicity. Environ. Toxicol. Chem. 2011;30:487–495. © 2010 SETAC
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measuring the toxicity of alkyl Phenanthrenes to early life stages of medaka oryzias latipes using partition controlled delivery
Environmental Toxicology and Chemistry, 2011Co-Authors: Dominique Turcotte, Michelle Bowerman, Yiannis Kiparissis, Stephen R Brown, Parveen Akhtar, Peter V. HodsonAbstract:Alkyl-Phenanthrenes are a class of compounds present in crude oil and toxic to developing fish. Most research on alkyl-Phenanthrenes has focused on retene (7-isopropyl-1-methyl-Phenanthrene), but little is known about the chronic toxicity of related congeners to the early life stages of fish. This project is the first to describe the chronic toxicity of a series of alkyl-Phenanthrenes to the embryos of Japanese medaka (Oryzias latipes) using the partition-controlled delivery (PCD) method of exposure and is the first to establish a relationship between toxicity of alkyl-Phenanthrenes and log P. With PCD, test concentrations were maintained by equilibrium partitioning of test chemicals from polydimethylsiloxane (PDMS) films containing various concentrations of C1 to C4 Phenanthrenes. Log film:solution partition constants (log K(fs)) and aqueous solubility limits were determined for each alkyl-Phenanthrene. The prevalence of abnormalities in fish embryos increased in an exposure-dependent manner, with median effective concentration (EC50) values lower than experimental solubility limits of the compounds, and typical of environmental concentrations. Alkyl-Phenanthrenes were more toxic to medaka embryos than unsubstituted Phenanthrene, with effects resembling those of dioxin and indicating a specific receptor-based mechanism of toxicity. These results extend conclusions for the Exxon Valdez oil spill, suggest a specific mechanism of toxicity for alkyl-Phenanthrenes, and provide a model for assessing the risks of mixture toxicity.
L Bezalel - One of the best experts on this subject based on the ideXlab platform.
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enzymatic mechanisms involved in Phenanthrene degradation by the white rot fungus pleurotus ostreatus
Applied and Environmental Microbiology, 1997Co-Authors: L Bezalel, Yitzhak Hadar, Carl E CernigliaAbstract:The enzymatic mechanisms involved in the degradation of Phenanthrene by the white rot fungus Pleurotus ostreatus were examined. Phase I metabolism (cytochrome P-450 monooxygenase and epoxide hydrolase) and phase II conjugation (glutathione S-transferase, aryl sulfotransferase, UDP-glucuronosyltransferase, and UDP-glucosyltransferase) enzyme activities were determined for mycelial extracts of P. ostreatus. Cytochrome P-450 was detected in both cytosolic and microsomal fractions at 0.16 and 0.38 nmol min(sup-1) mg of protein(sup1), respectively. Both fractions oxidized [9,10-(sup14)C]Phenanthrene to Phenanthrene trans-9,10-dihydrodiol. The cytochrome P-450 inhibitors 1-aminobenzotriazole (0.1 mM), SKF-525A (proadifen, 0.1 mM), and carbon monoxide inhibited the cytosolic and microsomal P-450s differently. Cytosolic and microsomal epoxide hydrolase activities, with Phenanthrene 9,10-oxide as the substrate, were similar, with specific activities of 0.50 and 0.41 nmol min(sup-1) mg of protein(sup-1), respectively. The epoxide hydrolase inhibitor cyclohexene oxide (5 mM) significantly inhibited the formation of Phenanthrene trans-9,10-dihydrodiol in both fractions. The phase II enzyme 1-chloro-2,4-dinitrobenzene glutathione S-transferase was detected in the cytosolic fraction (4.16 nmol min(sup-1) mg of protein(sup-1)), whereas aryl adenosine-3(prm1)-phosphate-5(prm1)-phosphosulfate sulfotransferase (aryl PAPS sulfotransferase) UDP-glucuronosyltransferase, and UDP-glucosyltransferase had microsomal activities of 2.14, 4.25, and 4.21 nmol min(sup-1) mg of protein(sup-1), respectively, with low activity in the cytosolic fraction. However, when P. ostreatus culture broth incubated with Phenanthrene was screened for phase II metabolites, no sulfate, glutathione, glucoside, or glucuronide conjugates of Phenanthrene metabolites were detected. These experiments indicate the involvement of cytochrome P-450 monooxygenase and epoxide hydrolase in the initial phase I oxidation of Phenanthrene to form Phenanthrene trans-9,10-dihydrodiol. Laccase and manganese-independent peroxidase were not involved in the initial oxidation of Phenanthrene. Although P. ostreatus had phase II xenobiotic metabolizing enzymes, conjugation reactions were not important for the elimination of hydroxylated Phenanthrene.
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metabolism of Phenanthrene by the white rot fungus pleurotus ostreatus
Applied and Environmental Microbiology, 1996Co-Authors: L Bezalel, Yitzhak Hadar, Peter P Fu, James P Freeman, Carl E CernigliaAbstract:The white rot fungus Pleurotus ostreatus, grown for 11 days in basidiomycetes rich medium containing [14C] Phenanthrene, metabolized 94% of the Phenanthrene added. Of the total radioactivity, 3% was oxidized to CO2. Approximately 52% of Phenanthrene was metabolized to trans-9,10-dihydroxy-9,10-dihydroPhenanthrene (Phenanthrene trans-9,10-dihydrodiol) (28%), 2,2'-diphenic acid (17%), and unidentified metabolites (7%). Nonextractable metabolites accounted for 35% of the total radioactivity. The metabolites were extracted with ethyl acetate, separated by reversed-phase high-performance liquid chromatography, and characterized by 1H nuclear magnetic resonance, mass spectrometry, and UV spectroscopy analyses. 18O2-labeling experiments indicated that one atom of oxygen was incorporated into the Phenanthrene trans-9,10-dihydrodiol. Circular dichroism spectra of the Phenanthrene trans-9,10-dihydrodiol indicated that the absolute configuration of the predominant enantiomer was 9R,10R, which is different from that of the principal enantiomer produced by Phanerochaete chrysosporium. Significantly less Phenanthrene trans-9,10-dihydrodiol was observed in incubations with the cytochrome P-450 inhibitor SKF 525-A (77% decrease), 1-aminobenzotriazole (83% decrease), or fluoxetine (63% decrease). These experiments with cytochrome P-450 inhibitors and 18O2 labeling and the formation of Phenanthrene trans-9R,10R-dihydrodiol as the predominant metabolite suggest that P. ostreatus initially oxidizes Phenanthrene stereoselectively by a cytochrome P-450 monoxygenase and that this is followed by epoxide hydrolase-catalyzed hydration reactions.
Houjie Liang - One of the best experts on this subject based on the ideXlab platform.
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saturated deep blue emitter based on a spiro benzoanthracene fluorene linked Phenanthrene derivative for non doped organic light emitting diodes
New Journal of Chemistry, 2014Co-Authors: Houjie Liang, Xinxin Wang, Xingye Zhang, Zhiyang Liu, Xinhua Ouyang, Suidong WangAbstract:A spiro[benzoanthracene–fluorene] derivative containing a Phenanthrene moiety, 2′,3-di(phenanthren-9-yl)spiro[benzo[de]anthracene-7,9′-fluorene] (DPSBAF), was prepared by a Suzuki coupling reaction. The photophysical and photochemical properties were investigated systematically. A non-doped organic light-emitting diode using DPSBAF as the emitter achieved a luminance efficiency of 2.18 cd A−1 with Commission Internationale de l'Eclairage 1931 chromaticity coordinates of (0.15, 0.09). The synthesized spiro[benzoanthracene–fluorene] derivative with a high thermal stability, a glass transition temperature of 210 °C and a decomposition temperature of 410 °C, shows potential for application in non-doped saturated deep-blue organic light-emitting diodes.