The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
Dick B. Janssen - One of the best experts on this subject based on the ideXlab platform.
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degradation of fluorobenzene by a rhizobiales strain f11 via ortho cleavage of 4 fluoroCatechol and Catechol
Journal of Biotechnology, 2007Co-Authors: Maria F. Carvalho, Maria Isabel M. Ferreira, Irina S. Moreira, Paula M. L. Castro, Dick B. JanssenAbstract:The aerobic metabolism of fluorobenzene by Rhizobiales sp. strain F11 was investigated. Liquid chromatography-mass spectrometry analysis showed that 4-fluoroCatechol and Catechol were formed as intermediates during fluorobenzene degradation by cell suspensions. Both these compounds, unlike 3-fluoroCatechol, supported growth and oxygen uptake. Cells grown on fluorobenzene contained enzymes for the ortho pathway but not for meta ring cleavage of Catechols. The results suggest that fluorobenzene is predominantly degraded via 4-fluoroCatechol with subsequent ortho cleavage and also partially via Catechol. During the last decades, environmental contamination by fluorinated organic compounds has received increasing attention because of their use as herbicides, fungicides, surfactants, refrigerants, intermediates in organic synthesis, solvents, and pharmaceuticals (11). Whereas the biodegradation of chlorinated compounds has been studied quite extensively (19), little is known about the bacterial metabolism of fluoroaromatic
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Degradation of fluorobenzene by Rhizobiales strain F11 via ortho cleavage of 4-fluoroCatechol and Catechol
Applied and Environmental Microbiology, 2006Co-Authors: Maria F. Carvalho, Maria Isabel M. Ferreira, Irina S. Moreira, Paula M. L. Castro, Dick B. JanssenAbstract:The aerobic metabolism of fluorobenzene by Rhizobiales sp. strain F11 was investigated. Liquid chromatography-mass spectrometry analysis showed that 4-fluoroCatechol and Catechol were formed as intermediates during fluorobenzene degradation by cell suspensions. Both these compounds, unlike 3-fluoroCatechol, supported growth and oxygen uptake. Cells grown on fluorobenzene contained enzymes for the ortho pathway but not for meta ring cleavage of Catechols. The results suggest that fluorobenzene is predominantly degraded via 4-fluoroCatechol with subsequent ortho cleavage and also partially via Catechol.
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conversion of 3 chloroCatechol by various Catechol 2 3 dioxygenases and sequence analysis of the chloroCatechol dioxygenase region of pseudomonas putida gj31
Journal of Bacteriology, 1999Co-Authors: Astrid E Mars, Walter Reineke, Jaap Kingma, Stefan R Kaschabek, Dick B. JanssenAbstract:Pseudomonas putida GJ31 contains an unusual Catechol 2,3-dioxygenase that converts 3-chloroCatechol and 3-methylCatechol, which enables the organism to use both chloroaromatics and methylaromatics for growth. A 3.1-kb region of genomic DNA of strain GJ31 containing the gene for this chloroCatechol 2,3-dioxygenase (cbzE) was cloned and sequenced. The cbzE gene appeared to be plasmid localized and was found in a region that also harbors genes encoding a transposase, a ferredoxin that was homologous to XylT, an open reading frame with similarity to a protein of a meta-cleavage pathway with unknown function, and a 2-hydroxymuconic semialdehyde dehydrogenase. CbzE was most similar to Catechol 2,3-dioxygenases of the 2.C subfamily of type 1 extradiol dioxygenases (L. D. Eltis and J. T. Bolin, J. Bacteriol. 178:5930–5937, 1996). The substrate range and turnover capacity with 3-chloroCatechol were determined for CbzE and four related Catechol 2,3-dioxygenases. The results showed that CbzE was the only enzyme that could productively convert 3-chloroCatechol. Besides, CbzE was less susceptible to inactivation by methylated Catechols. Hybrid enzymes that were made of CzbE and the Catechol 2,3-dioxygenase of P. putida UCC2 (TdnC) showed that the resistance of CbzE to suicide inactivation and its substrate specificity were mainly determined by the C-terminal region of the protein.
Jacob N. Israelachvili - One of the best experts on this subject based on the ideXlab platform.
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impact of molecular architecture and adsorption density on adhesion of mussel inspired surface primers with Catechol cation synergy
Journal of the American Chemical Society, 2019Co-Authors: George D Degen, Parker R Stow, Robert B Lewis, Eric Valois, Roberto Andresen C Eguiluz, Alison Butler, Kai Kristiansen, Jacob N. IsraelachviliAbstract:Marine mussels secrete proteins rich in residues containing Catechols and cationic amines that displace hydration layers and adhere to charged surfaces under water via a cooperative binding effect known as Catechol-cation synergy. Mussel-inspired adhesives containing paired Catechol and cationic functionalities are a promising class of materials for biomedical applications, but few studies address the molecular adhesion mechanism(s) of these materials. To determine whether intramolecular adjacency of these functionalities is necessary for robust adhesion, a suite of siderophore analog surface primers was synthesized with systematic variations in intramolecular spacing between Catechol and cationic functionalities. Adhesion measurements conducted with a surface forces apparatus (SFA) allow adhesive failure to be distinguished from cohesive failure and show that the failure mode depends critically on the siderophore analog adsorption density. The adhesion of these molecules to muscovite mica in an aqueous e...
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impact of molecular architecture and adsorption density on adhesion of mussel inspired surface primers with Catechol cation synergy
Journal of the American Chemical Society, 2019Co-Authors: George D Degen, Parker R Stow, Robert B Lewis, Eric Valois, Roberto Andresen C Eguiluz, Alison Butler, Kai Kristiansen, Jacob N. IsraelachviliAbstract:Marine mussels secrete proteins rich in residues containing Catechols and cationic amines that displace hydration layers and adhere to charged surfaces under water via a cooperative binding effect known as Catechol-cation synergy. Mussel-inspired adhesives containing paired Catechol and cationic functionalities are a promising class of materials for biomedical applications, but few studies address the molecular adhesion mechanism(s) of these materials. To determine whether intramolecular adjacency of these functionalities is necessary for robust adhesion, a suite of siderophore analog surface primers was synthesized with systematic variations in intramolecular spacing between Catechol and cationic functionalities. Adhesion measurements conducted with a surface forces apparatus (SFA) allow adhesive failure to be distinguished from cohesive failure and show that the failure mode depends critically on the siderophore analog adsorption density. The adhesion of these molecules to muscovite mica in an aqueous electrolyte solution demonstrates that direct intramolecular adjacency of Catechol and cationic functionalities is not necessary for synergistic binding. However, we show that increasing the Catechol-cation spacing by incorporating nonbinding domains results in decreased adhesion, which we attribute to a decrease in the density of Catechol functionalities. A mechanism for Catechol-cation synergy is proposed based on electrostatically driven adsorption and subsequent binding of Catechol functionalities. This work should guide the design of new adhesives for binding to charged surfaces in saline environments.
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defining the Catechol cation synergy for enhanced wet adhesion to mineral surfaces
Journal of the American Chemical Society, 2016Co-Authors: Michael V Rapp, Alison Butler, Greg P Maier, Howard A Dobbs, Nicholas J Higdon, Herbert J Waite, Jacob N. IsraelachviliAbstract:Mussel foot proteins (Mfps) exhibit remarkably adaptive adhesion and bridging between polar surfaces in aqueous solution despite the strong hydration barriers at the solid–liquid interface. Recently, Catechols and amines—two functionalities that account for >50 mol % of the amino acid side chains in surface-priming Mfps—were shown to cooperatively displace the interfacial hydration and mediate robust adhesion between mineral surfaces. Here we demonstrate that (1) synergy between Catecholic and guanidinium side chains similarly promotes adhesion, (2) increasing the ratio of cationic amines to Catechols in a molecule reduces adhesion, and (3) the Catechol–cation synergy is greatest when both functionalities are present within the same molecule.
Anna Radominskapandya - One of the best experts on this subject based on the ideXlab platform.
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glucuronidation of Catechols by human hepatic gastric and intestinal microsomal udp glucuronosyltransferases ugt and recombinant ugt1a6 ugt1a9 and ugt2b7
Archives of Biochemistry and Biophysics, 2003Co-Authors: Laurence Antonio, Brian Burchell, Jacques Magdalou, Joanna M Little, Jing Xu, Anna RadominskapandyaAbstract:Abstract The substrate specificity of human gastric and intestinal UDP-glucuronosyltransferases (UGTs) toward Catechols was investigated and compared to that of liver UGTs. Small Catechols were efficiently glucuronidated by stomach (0.8–10.2 nmol/mg protein·min) and intestine (0.9–7.7 nmol/mg protein·min) with activities in a range similar to those found in liver (2.9–19 nmol/mg protein·min). Large interindividual variations were observed among the samples. Immunoblot analysis demonstrated the presence of UGT1A6 and UGT2B7 in stomach and throughout the intestine. Recombinant human UGT1A6, 1A9, and 2B7, stably expressed in mammalian cells, all effectively catalyzed Catechol glucuronidation. K m values (0.09–13.6 mM) indicated low affinity for UGTs and V max values ranged from 0.51 to 64.0 nmol/mg protein·min. These results demonstrate for the first time glucuronidation of Catechols by gastric and intestinal microsomal UGTs and three human recombinant UGT isoforms.
Maria F. Carvalho - One of the best experts on this subject based on the ideXlab platform.
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degradation of fluorobenzene by a rhizobiales strain f11 via ortho cleavage of 4 fluoroCatechol and Catechol
Journal of Biotechnology, 2007Co-Authors: Maria F. Carvalho, Maria Isabel M. Ferreira, Irina S. Moreira, Paula M. L. Castro, Dick B. JanssenAbstract:The aerobic metabolism of fluorobenzene by Rhizobiales sp. strain F11 was investigated. Liquid chromatography-mass spectrometry analysis showed that 4-fluoroCatechol and Catechol were formed as intermediates during fluorobenzene degradation by cell suspensions. Both these compounds, unlike 3-fluoroCatechol, supported growth and oxygen uptake. Cells grown on fluorobenzene contained enzymes for the ortho pathway but not for meta ring cleavage of Catechols. The results suggest that fluorobenzene is predominantly degraded via 4-fluoroCatechol with subsequent ortho cleavage and also partially via Catechol. During the last decades, environmental contamination by fluorinated organic compounds has received increasing attention because of their use as herbicides, fungicides, surfactants, refrigerants, intermediates in organic synthesis, solvents, and pharmaceuticals (11). Whereas the biodegradation of chlorinated compounds has been studied quite extensively (19), little is known about the bacterial metabolism of fluoroaromatic
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Degradation of fluorobenzene by Rhizobiales strain F11 via ortho cleavage of 4-fluoroCatechol and Catechol
Applied and Environmental Microbiology, 2006Co-Authors: Maria F. Carvalho, Maria Isabel M. Ferreira, Irina S. Moreira, Paula M. L. Castro, Dick B. JanssenAbstract:The aerobic metabolism of fluorobenzene by Rhizobiales sp. strain F11 was investigated. Liquid chromatography-mass spectrometry analysis showed that 4-fluoroCatechol and Catechol were formed as intermediates during fluorobenzene degradation by cell suspensions. Both these compounds, unlike 3-fluoroCatechol, supported growth and oxygen uptake. Cells grown on fluorobenzene contained enzymes for the ortho pathway but not for meta ring cleavage of Catechols. The results suggest that fluorobenzene is predominantly degraded via 4-fluoroCatechol with subsequent ortho cleavage and also partially via Catechol.
Laurence Antonio - One of the best experts on this subject based on the ideXlab platform.
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glucuronidation of Catechols by human hepatic gastric and intestinal microsomal udp glucuronosyltransferases ugt and recombinant ugt1a6 ugt1a9 and ugt2b7
Archives of Biochemistry and Biophysics, 2003Co-Authors: Laurence Antonio, Brian Burchell, Jacques Magdalou, Joanna M Little, Jing Xu, Anna RadominskapandyaAbstract:Abstract The substrate specificity of human gastric and intestinal UDP-glucuronosyltransferases (UGTs) toward Catechols was investigated and compared to that of liver UGTs. Small Catechols were efficiently glucuronidated by stomach (0.8–10.2 nmol/mg protein·min) and intestine (0.9–7.7 nmol/mg protein·min) with activities in a range similar to those found in liver (2.9–19 nmol/mg protein·min). Large interindividual variations were observed among the samples. Immunoblot analysis demonstrated the presence of UGT1A6 and UGT2B7 in stomach and throughout the intestine. Recombinant human UGT1A6, 1A9, and 2B7, stably expressed in mammalian cells, all effectively catalyzed Catechol glucuronidation. K m values (0.09–13.6 mM) indicated low affinity for UGTs and V max values ranged from 0.51 to 64.0 nmol/mg protein·min. These results demonstrate for the first time glucuronidation of Catechols by gastric and intestinal microsomal UGTs and three human recombinant UGT isoforms.
