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Sample records for catechol

  1. How Many Drugs Are Catecholics

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    Da-Peng Yang

    2007-04-01

    Full Text Available By examination of the 8659 drugs recorded in the Comprehensive Medicinal Chemistry (CMC database, 78 catecholics (including five pyrogallolics were identified, of which 17 are currently prescribed by FDA. Through analyzing the substitutent patterns, ClogPs and O-H bond dissociation enthalpies(BDEs of the catecholic drugs, some molecular features that may benefit circumventing the toxicity of catecholics were revealed: i strong electron-donating substituents are excluded; ii ClogP 3; iii an energy penalty exists for quinone formation. Besides, the present analyses also suggest that the clinical usage and dosage of currently prescribed catecholic drugs are of importance in designing or screening catecholic antioxidants.

  2. The Three Catecholics Benserazide, Catechol and Pyrogallol are GPR35 Agonists

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    Huayun Deng

    2013-04-01

    Full Text Available Nearly 1% of all clinically used drugs are catecholics, a family of catechol-containing compounds. Using label-free dynamic mass redistribution and Tango β-arrestin translocation assays, we show that several catecholics, including benserazide, catechol, 3-methoxycatechol, pyrogallol, (+-taxifolin and fenoldopam, display agonistic activity against GPR35.

  3. Catechol biodegradation kinetics using Candida parapsilopsis

    OpenAIRE

    Maurício Rigo; Ranulfo Monte Alegre; José Raniere Mazile Vidal Bezerra; Narjara Coelho; Reinaldo Gaspar Bastos

    2010-01-01

    This study evaluated the biodegradation of catechol by a yeast strain of Candida parapsilopsis in standard medium in Erlenmeyer flasks. Results shown that the highest concentration of catechol caused the longer lag period, demonstrating that acclimatized cultures could completely degrade an initial catechol concentration of 910 mg/L within 48 h. Haldane's model validated the experimental data adequately for growth kinetics over the studied catechol concentration ranges of 36 to 910 mg/L. The ...

  4. Production of catechols: microbiology and technology

    NARCIS (Netherlands)

    Krab-Hüsken, L.E.

    2002-01-01

    Catechols play an important role in the fine-chemical and flavour industry, as well as in photography, dyeing fur, rubber and plastic production. Many of these compounds cannot easily be synthesised chemically, but some micro-organisms are capable of producing catechols fro

  5. A redox-neutral catechol synthesis.

    Science.gov (United States)

    Wu, Qian; Yan, Dingyuan; Chen, Ying; Wang, Ting; Xiong, Feng; Wei, Wei; Lu, Yi; Sun, Wei-Yin; Li, Jie Jack; Zhao, Jing

    2017-01-27

    Ubiquitous tyrosinase catalyses the aerobic oxidation of phenols to catechols through the binuclear copper centres. Here, inspired by the Fischer indole synthesis, we report an iridium-catalysed tyrosinase-like approach to catechols, employing an oxyacetamide-directed C-H hydroxylation on phenols. This method achieves one-step, redox-neutral synthesis of catechols with diverse substituent groups under mild conditions. Mechanistic studies confirm that the directing group (DG) oxyacetamide acts as the oxygen source. This strategy has been applied to the synthesis of different important catechols with fluorescent property and bioactivity from the corresponding phenols. Finally, our method also provides a convenient route to (18)O-labelled catechols using (18)O-labelled acetic acid.

  6. A redox-neutral catechol synthesis

    Science.gov (United States)

    Wu, Qian; Yan, Dingyuan; Chen, Ying; Wang, Ting; Xiong, Feng; Wei, Wei; Lu, Yi; Sun, Wei-Yin; Li, Jie Jack; Zhao, Jing

    2017-01-01

    Ubiquitous tyrosinase catalyses the aerobic oxidation of phenols to catechols through the binuclear copper centres. Here, inspired by the Fischer indole synthesis, we report an iridium-catalysed tyrosinase-like approach to catechols, employing an oxyacetamide-directed C-H hydroxylation on phenols. This method achieves one-step, redox-neutral synthesis of catechols with diverse substituent groups under mild conditions. Mechanistic studies confirm that the directing group (DG) oxyacetamide acts as the oxygen source. This strategy has been applied to the synthesis of different important catechols with fluorescent property and bioactivity from the corresponding phenols. Finally, our method also provides a convenient route to 18O-labelled catechols using 18O-labelled acetic acid.

  7. Boronate Derivatives of Functionally Diverse Catechols: Stability Studies

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    Kamal Aziz Ketuly

    2010-03-01

    Full Text Available Benzeneboronate of catecholic carboxyl methyl esters, N-acetyldopamine, coumarin and catechol estrogens were prepared as crystalline derivatives in high yield. Related catechol compounds with extra polar functional group(s (OH, NH2 do not form or only partially form unstable cyclic boronate derivatives.

  8. The role of catechol-O-methyltransferase in catechol-enhanced erythroid differentiation of K562 cells

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    Suriguga,; Li, Xiao-Fei; Li, Yang; Yu, Chun-Hong; Li, Yi-Ran; Yi, Zong-Chun, E-mail: yizc@buaa.edu.cn

    2013-12-15

    Catechol is widely used in pharmaceutical and chemical industries. Catechol is also one of phenolic metabolites of benzene in vivo. Our previous study showed that catechol improved erythroid differentiation potency of K562 cells, which was associated with decreased DNA methylation in erythroid specific genes. Catechol is a substrate for the catechol-O-methyltransferase (COMT)-mediated methylation. In the present study, the role of COMT in catechol-enhanced erythroid differentiation of K562 cells was investigated. Benzidine staining showed that exposure to catechol enhanced hemin-induced hemoglobin accumulation and induced mRNA expression of erythroid specific genes in K562 cells. Treatment with catechol caused a time- and concentration-dependent increase in guaiacol concentration in the medium of cultured K562 cells. When COMT expression was knocked down by COMT shRNA expression in K562 cells, the production of guaiacol significantly reduced, and the sensitivity of K562 cells to cytotoxicity of catechol significantly increased. Knockdown of COMT expression by COMT shRNA expression also eliminated catechol-enhanced erythroid differentiation of K562 cells. In addition, the pre-treatment with methyl donor S-adenosyl-L-methionine or its demethylated product S-adenosyl-L-homocysteine induced a significant increase in hemin-induced Hb synthesis in K562 cells and the mRNA expression of erythroid specific genes. These findings indicated that O-methylation catalyzed by COMT acted as detoxication of catechol and involved in catechol-enhanced erythroid differentiation of K562 cells, and the production of S-adenosyl-L-homocysteine partly explained catechol-enhanced erythroid differentiation. - Highlights: • Catechol enhanced hemin-induced hemoglobin accumulation. • COMT-catalyzed methylation acted as detoxication of catechol. • COMT involved in catechol-enhanced erythroid differentiation.

  9. Aluminum complexation by catechol as determined by ultraviolet spectrophotometry

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    Sikora, F.J.; McBride, M.B.

    1989-03-01

    Methods of ultraviolet (UV) spectrophotometry were used to determine the stoichiometry and association constant for the Al-catechol complex from pH 3.8 to 4.6. Job's method of continuous variation indicated the Al-catechol complex had a 1:1 stoichiometry in the pH range studied. Aluminum titrations of catechol and pH titrations of catechol plus Al resulted in a shift in the UV spectra due to the formation of an Al-catechol complex absorbing UV radiation uniquely different than that of free catechol. General equations were developed for the determination of association constants assuming an organic and Al-organic complex absorb UV radiation. Aluminum titrations with constant catechol concentration yielded a log k/sub 0.1//sup c/ of 16.22 for a 1:1 Al-catechol complex. Calculated absorbance as a function of pH agree dwell with experimental pH titrations of solutions containing catechol plus Al. The fact that Al can be complexed by catechol at low pH indicates the o-hydroxy group provides a potential source for Al complexation in soil and surface waters.

  10. Endogenous catechol thioethers may be pro-oxidant or antioxidant.

    Science.gov (United States)

    Picklo, M J; Amarnath, V; Graham, D G; Montine, T J

    1999-08-01

    Increased catechol thioether formation is associated with Parkinson's disease. In this study, we examined whether catechol thioethers, having a lower oxidation potential than their parent catechols, would cause greater oxidative damage than their parent catechols. We synthesized 5'-S-glutathionyl, cysteinyl, and N-acetylcysteinyl derivatives of dopamine and dopac, encompassing the known catechol thioethers of the mercapturate pathway. Cyclic voltametry studies showed that catechol thioethers had higher reduction potentials than their parent catechols. A higher reduction potential did not correlate with an increase in oxidative damage, measured by metal-catalyzed DNA strand breakage. 5'-S-Glutathionyldopamine and the cysteinyl adducts of dopamine and dopac mediated less oxidative damage than their parent catechols. In contrast, both N-acetylcysteinyl analogs were equipotent to dopamine. Oxygen consumption corresponded to DNA damage except for 5'-S-glutathionyldopamine. The glutathionyl and cysteinyl adducts of dopamine inhibited dopamine-mediated DNA damage indicating that these adducts may have antioxidant properties. 5'-S-Glutathionyldopamine potentiated H2O2-mediated damage whereas 5-S-cysteinyldopamine was inhibitory. Our results show that the ability of catechol thioethers to cause oxidative damage in vitro is not based simply upon the reduction potential but rather, reflects a complex relationship among structures of the parent catechol and thiol adduct, metal catalyst, and oxidant.

  11. The role of catechol-O-methyltransferase in catechol-enhanced erythroid differentiation of K562 cells.

    Science.gov (United States)

    Suriguga; Li, Xiao-Fei; Li, Yang; Yu, Chun-Hong; Li, Yi-Ran; Yi, Zong-Chun

    2013-12-15

    Catechol is widely used in pharmaceutical and chemical industries. Catechol is also one of phenolic metabolites of benzene in vivo. Our previous study showed that catechol improved erythroid differentiation potency of K562 cells, which was associated with decreased DNA methylation in erythroid specific genes. Catechol is a substrate for the catechol-O-methyltransferase (COMT)-mediated methylation. In the present study, the role of COMT in catechol-enhanced erythroid differentiation of K562 cells was investigated. Benzidine staining showed that exposure to catechol enhanced hemin-induced hemoglobin accumulation and induced mRNA expression of erythroid specific genes in K562 cells. Treatment with catechol caused a time- and concentration-dependent increase in guaiacol concentration in the medium of cultured K562 cells. When COMT expression was knocked down by COMT shRNA expression in K562 cells, the production of guaiacol significantly reduced, and the sensitivity of K562 cells to cytotoxicity of catechol significantly increased. Knockdown of COMT expression by COMT shRNA expression also eliminated catechol-enhanced erythroid differentiation of K562 cells. In addition, the pre-treatment with methyl donor S-adenosyl-L-methionine or its demethylated product S-adenosyl-L-homocysteine induced a significant increase in hemin-induced Hb synthesis in K562 cells and the mRNA expression of erythroid specific genes. These findings indicated that O-methylation catalyzed by COMT acted as detoxication of catechol and involved in catechol-enhanced erythroid differentiation of K562 cells, and the production of S-adenosyl-L-homocysteine partly explained catechol-enhanced erythroid differentiation.

  12. Reaction pathways in catechol/primary amine mixtures

    OpenAIRE

    Yang, Juan; Saggiomo, Vittorio; Velders, Aldrik H.; Cohen Stuart, Martien; Kamperman, Marleen

    2016-01-01

    Catechol chemistry is used as a crosslinking tool abundantly in both natural organisms (e.g. mussels, sandcastle worms) and synthetic systems to achieve the desired mechanical properties. Despite this abundance and success, the crosslinking chemistry is still poorly understood. In this study, to simplify the system, yet to capture the essential chemistry, model compounds 4-methyl catechol and propylamine are used. The reaction of 4-methyl catechol (2 mM) with propylamine (6 mM) is carried out...

  13. Catechol-based biomimetic functional materials

    OpenAIRE

    Sedó, Josep; Saiz-Poseu, Javier; Busqué, Félix; Ruiz Molina, Daniel

    2013-01-01

    Catechols are found in nature taking part in a remarkably broad scope of biochemical processes and functions. Though not exclusively, such versatility may be traced back to several properties uniquely found together in the o-dihydroxyaryl chemical function; namely, its ability to establish reversible equilibria at moderate redox potentials and pHs and to irreversibly cross-link through complex oxidation mechanisms; its excellent chelating properties, greatly exemplified by, but by no means ex...

  14. Catechol Siderophore Transport by Vibrio cholerae

    OpenAIRE

    Wyckoff, Elizabeth E.; Allred, Benjamin E.; Raymond, Kenneth N.; Payne, Shelley M

    2015-01-01

    Siderophores, small iron-binding molecules secreted by many microbial species, capture environmental iron for transport back into the cell. Vibrio cholerae synthesizes and uses the catechol siderophore vibriobactin and also uses siderophores secreted by other species, including enterobactin produced by Escherichia coli. E. coli secretes both canonical cyclic enterobactin and linear enterobactin derivatives likely derived from its cleavage by the enterobactin esterase Fes. We show here that V....

  15. Catechol-O-methyltransferase and Parkinson's disease.

    OpenAIRE

    Tai CH; Wu RM

    2002-01-01

    Parkinson's disease (PD) is one of the main causes of neurological disability in the elderly. Levodopa is the gold standard for treating this disease, but chronic levodopa therapy is complicated by motor fluctuation and dyskinesia. The catechol-O-methyltransferase (COMT) inhibitors represent a new class of antiparkinsonian drugs. When coadministered with levodopa/decarboxylase inhibitor, 2 COMT inhibitors, tolcapone and entacapone have been shown to improve the clinical benefit of levodopa. C...

  16. Catechol biodegradation kinetics using Candida parapsilopsis

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    Maurício Rigo

    2010-04-01

    Full Text Available This study evaluated the biodegradation of catechol by a yeast strain of Candida parapsilopsis in standard medium in Erlenmeyer flasks. Results shown that the highest concentration of catechol caused the longer lag period, demonstrating that acclimatized cultures could completely degrade an initial catechol concentration of 910 mg/L within 48 h. Haldane's model validated the experimental data adequately for growth kinetics over the studied catechol concentration ranges of 36 to 910 mg/L. The constants obtained for this model were µmax = 0.246 h-1, Ks = 16.95 mg/L and Ki = 604.85 mg/L.Neste trabalho foi estudada a biodegradação de catecol em frascos de Erlenmeyers em água residuária sintética pela levedura Candida parapsilopsis. As respostas dos ensaios cinéticos mostraram que altas concentrações de catecol ocasionaram uma fase lag longa para a levedura. Portanto, a aclimatização da cultura de levedura empregada para biodegradação de catecol é de fundamental importância, sendo possível reduzir toda a concentração inicial de catecol da água residuária sintética de 910 mg/L em 48 horas. Os dados experimentais da cinética de biodegradação do catecol foram ajustados pelo modelo de Haldane adequadamente, sobre a faixa de concentração de catecol investigada de 36 a 910 mg/L. Os parâmetros cinéticos obtidos do modelo de Haldane foram: µmax = 0,246 h-1, Ks = 16,95 mg/L e Ki = 604,85 mg/L.

  17. Synthesis and Evaluation of Heterocyclic Catechol Mimics as Inhibitors of Catechol-O-methyltransferase (COMT)

    Science.gov (United States)

    2015-01-01

    3-Hydroxy-4-pyridinones and 5-hydroxy-4-pyrimidinones were identified as inhibitors of catechol-O-methyltransferase (COMT) in a high-throughput screen. These heterocyclic catechol mimics exhibit potent inhibition of the enzyme and an improved toxicity profile versus the marketed nitrocatechol inhibitors tolcapone and entacapone. Optimization of the series was aided by X-ray cocrystal structures of the novel inhibitors in complex with COMT and cofactors SAM and Mg2+. The crystal structures suggest a mechanism of inhibition for these heterocyclic inhibitors distinct from previously disclosed COMT inhibitors. PMID:25815153

  18. Catechol Siderophore Transport by Vibrio cholerae

    Science.gov (United States)

    Allred, Benjamin E.; Raymond, Kenneth N.; Payne, Shelley M.

    2015-01-01

    ABSTRACT Siderophores, small iron-binding molecules secreted by many microbial species, capture environmental iron for transport back into the cell. Vibrio cholerae synthesizes and uses the catechol siderophore vibriobactin and also uses siderophores secreted by other species, including enterobactin produced by Escherichia coli. E. coli secretes both canonical cyclic enterobactin and linear enterobactin derivatives likely derived from its cleavage by the enterobactin esterase Fes. We show here that V. cholerae does not use cyclic enterobactin but instead uses its linear derivatives. V. cholerae lacked both a receptor for efficient transport of cyclic enterobactin and enterobactin esterase to promote removal of iron from the ferrisiderophore complex. To further characterize the transport of catechol siderophores, we show that the linear enterobactin derivatives were transported into V. cholerae by either of the catechol siderophore receptors IrgA and VctA, which also transported the synthetic siderophore MECAM [1,3,5-N,N′,N″-tris-(2,3-dihydroxybenzoyl)-triaminomethylbenzene]. Vibriobactin is transported via the additional catechol siderophore receptor ViuA, while the Vibrio fluvialis siderophore fluvibactin was transported by all three catechol receptors. ViuB, a putative V. cholerae siderophore-interacting protein (SIP), functionally substituted for the E. coli ferric reductase YqjH, which promotes the release of iron from the siderophore in the bacterial cytoplasm. In V. cholerae, ViuB was required for the use of vibriobactin but was not required for the use of MECAM, fluvibactin, ferrichrome, or the linear derivatives of enterobactin. This suggests the presence of another protein in V. cholerae capable of promoting the release of iron from these siderophores. IMPORTANCE Vibrio cholerae is a major human pathogen and also serves as a model for the Vibrionaceae, which include other serious human and fish pathogens. The ability of these species to persist and

  19. Copper complexes as biomimetic models of catechol oxidase : mechanistic studies

    NARCIS (Netherlands)

    Koval, Iryna A.

    2006-01-01

    The research described in this thesis deals with the synthesis of copper(II) complexes with phenol-based or macrocyclic ligands, which can be regarded as model compounds of the active site of catechol oxidase, and with the mechanism of the catalytic oxidation of catechol mediated by these compounds.

  20. Jack of all trades: Versatile catechol crosslinking mechanisms

    NARCIS (Netherlands)

    Yang, J.; Cohen Stuart, M.A.; Kamperman, M.M.G.

    2014-01-01

    Catechols play an important role in many natural systems. They are known to readily interact with both organic (e.g., amino acids) and inorganic (e.g., metal ions, metal oxides) compounds, thereby providing a powerful system for protein curing. Catechol crosslinked protein networks, such as scleroti

  1. Abiotic oxidation of catechol by soil metal oxides

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    Colarieti, Maria Letizia [Dipartimento di Ingegneria Chimica, Universita di Napoli Federico II, Naples (Italy); Toscano, Giuseppe [Dipartimento di Ingegneria Chimica, Universita di Napoli Federico II, Naples (Italy)]. E-mail: giuseppe.toscano@unina.it; Ardi, Maria Raffaella [Dipartimento di Ingegneria Chimica, Universita di Napoli Federico II, Naples (Italy); Greco, Guido [Dipartimento di Ingegneria Chimica, Universita di Napoli Federico II, Naples (Italy)

    2006-06-30

    The mechanism of catechol oxidation by soil metal oxides is investigated in a slurry reactor. This abiotic transformation is shown to consist in a three-step process. The first step is a heterogeneous reaction. Catechol undergoes fast, partial oxidation at the expenses of Fe and Mn oxides contained in the soil. In the second step, reduced Fe and Mn are released into the aqueous solution and immediately complexed by catechol. Metal-catecholate complexes are stable at the very low dissolved-oxygen concentration levels attained under nitrogen sparging. The third step is a homogenous reaction. The highly reactive intermediate produced by catechol partial oxidation initiates catechol polymerisation. Under nitrogen sparging, the polymerisation process ends rather rapidly, thus yielding only partial conversion of the phenol and producing low-molecular weight, water-soluble polymers. Further oxidation of the metal-catecholate complexes formed in the second step only occurs under air sparging. Thus, reactive intermediates are formed at much higher concentration levels than those attained when nearly no oxygen is present in solution. The polymerisation proceeds at a much faster rate until, under the experimental conditions adopted, complete catechol conversion is attained and high-molecular-weight, insoluble polymers are produced.

  2. Adsorption mechanism and valency of catechol-functionalized hyperbranched polyglycerols

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    Stefanie Krysiak

    2015-05-01

    Full Text Available Nature often serves as a model system for developing new adhesives. In aqueous environments, mussel-inspired adhesives are promising candidates. Understanding the mechanism of the extraordinarily strong adhesive bonds of the catechol group will likely aid in the development of adhesives. With this aim, we study the adhesion of catechol-based adhesives to metal oxides on the molecular level using atomic force microscopy (AFM. The comparison of single catechols (dopamine with multiple catechols on hyperbranched polyglycerols (hPG at various pH and dwell times allowed us to further increase our understanding. In particular, we were able to elucidate how to achieve strong bonds of different valency. It was concluded that hyperbranched polyglycerols with added catechol end groups are promising candidates for durable surface coatings.

  3. Heterogeneous cracking of catechol under partially oxidative conditions

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    Eun-Jae Shin; Mohammad R. Hajaligol; Firooz Rasouli [Philip Morris USA, Richmond, VA (United States). Research Center

    2004-08-01

    Heterogeneous cracking of catechol over the temperature range of 350-650{sup o}C and under partially oxidative conditions was studied using nano-particle iron oxide. We employed a flow tube reactor set-up for heterogeneous cracking, a molecular beam mass spectrometer for the real time sampling and measurement of cracking products, and factor analysis to deconvolute the complex chemistry. The effects on conversion and products distribution of varying process parameters such as catechol feed rate, oxygen concentration, and temperature were considered. Thermal decomposition of catechol begins at above 500{sup o}C. In the presence of the iron oxide, however, catechol significantly decomposes at temperatures as low as 350{sup o}C. The formation of carbon dioxide and water was promoted at the lower catechol feed rates. Higher catechol feed rates suppressed the conversion and enhanced the formation of single ring aromatic products, especially the formation of an aromatic ketone, indanone (m/z 132, C{sub 9}H{sub 8}O), through gas-phase secondary reactions. Increasing oxygen concentration up to 21%, however, completed the cracking of catechol with increasing formation of carbon dioxide and water even at 350{sup o}C for a high catechol feed rate. The iron oxide was deactivated after being exposed to the vapor of catechol at lower temperatures (between 350 and 400{sup o}C). However, it retained its activity at temperatures above 450{sup o}C. High-resolution transmission electron microscopy was used to characterize the iron oxide nano-particles at various reaction conditions. 42 refs., 9 figs.

  4. Application of electrosynthesized poly(aniline-co-p-aminophenol) as a catechol sensor

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    Chen Chuanxiang [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Department of Chemistry, School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003 (China)], E-mail: cxchenyz@yahoo.com.cn; Sun Cheng [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China)], E-mail: envidean@nju.edu.cn; Gao Yuhua [Department of Chemistry, School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003 (China)

    2009-03-30

    Poly(aniline-co-p-aminophenol) (copolymer) film was used as a sensor to determine the presence of catechol, taking advantage of the ability of the film to effectively catalyze the oxidation of catechol. The copolymer served as an electron transfer mediator between the electrode surface and catechol in the solution. The response current of the catechol sensor depended on the applied potential, pH and temperature at a given concentration of catechol. At optimum conditions, the catechol sensor displayed an excellent electrocatalytic response to the detection of catechol in a concentration range from 5 to 500 {mu}M with a detection limit of 0.8 {mu}M. The effects of selected organic compounds on the response of the catechol sensor were studied. Together, these findings show that the catechol sensor exhibits a better selectivity towards interfering species and a better operational and storage stability.

  5. Degradation of recalcitrant compounds by catechol-driven Fenton reaction

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    Rodriguez, J.; Contreras, D.; Oviedo, C.; Freer, J.; Baeza, J. [Renewable Resources Lab., Univ. de Concepcion, Concepcion (Chile)

    2003-07-01

    Dihydroxybenzenes are able to reduce Fe(III) and promote fenton reaction. The Catechol/Fe(III)/H{sub 2}O{sub 2} system has been successfully used to degrade different compounds, being in all cases more efficient than Fe(II)-Fenton reaction. In this paper the possibilities for using the catechol-driven fenton reaction to degrade recalcitrant compounds such as Fe(III)-EDTA complex and veratryl alcohol are reviewed. (orig.)

  6. Chemisorption of catechol on gibbsite, boehmite, and noncrystalline alumina surfaces

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    McBride, M.B.; Wesselink, L.G.

    1988-06-01

    The mechanism of bonding of catechol and related phenolic compounds on aluminum oxides was elucidated from sorption behavior in the presence of competing adsorbates and the nature of the infrared spectra of the surface-bound molecules. The surfaces demonstrated a high degree of selectivity toward catechol, adsorbing the molecule in the presence of a large excess of chloride. Phosphate competed effectively with catechol for sorption sites while acetate did not. Dispersive and Fourier transform infrared spectroscopy verified that catechol bound on the aluminum oxide surfaces was chemically perturbed in much the same manner as catechol chelated by Al/sup 3 +/, suggesting that the dominant sorption process involved the formation of a 1:1 bidentate complex with surface Al. The mechanisms of bonding was similar for all the aluminum oxides, but the dominant crystal surfaces of the crystalline oxides were unreactive toward catechol, and adsorption was attributed to -AlOH groups situated on edge faces. As a result, the noncrystalline oxide was more reactive per unit of surface area than the crystalline minerals boehmite and gibbsite.

  7. Cytotoxic effects of catechols to glial and neuronal cells

    Directory of Open Access Journals (Sweden)

    Ramon Santos El-Bachá

    2015-04-01

    Full Text Available Catechols are compounds that autoxidises under physiological conditions leading to the formation of reactive oxygen species (ROS, semiquinones, and quinones. These molecules can be formed in organisms because of the metabolism of exogenous aromatic substances, such as benzene. However, there are several important endogenous catechols, which have physiological functions, such as catecholamines. Furthermore, several pharmacological agents are catechols, such as apomorphine, or can be metabolised to generate these compounds. In this presentation we will show that apomorphine can unspecifically bind to proteins during its autoxidation, a phenomenon that is inhibited by thiols. Brain endothelial cells and glial cells express xenobiotic-metabolising enzymes as components of the metabolic blood-brain barrier in an attempt to protect the central nervous system against drugs. Since UDP-glucuronosyltransferases (EC 2.4.1.17 are among these enzymes, we investigated the ability of brain microsomes to conjugate catechols with glucuronate. Despite the fact that 1-naphtol could be glucuronidated in the presence of brain cortex microsomes, the same was not observed for most of catechols that were tested. Therefore, this is not the main mechanism used to protect the brain against them. Indeed, catechols may inhibit other xenobiotic-metabolising enzymes. We showed that apomorphine inhibited the cytochrome P450-dependent dealkylation activity. The production of ROS and reactive quinones, as well as their effects on protein functions, seems to be involved in the cytotoxicity of catechols. Glial cells are more resistant than neuronal cells. Apomorphine was more toxic to rat neurons than to rat C6 glioma cells. 1,2-Dihydroxybenzene (catechol killed human GL-15 cells with an EC50 of 230 uM after 72 h, a effect that was significantly inhibited by superoxide dismutase (EC 1.15.1.1. Another mechanism that we found to be involved in catechol cytotoxicity is the inhibition

  8. Some properties of active and latent catechol oxidase of mushroom

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    Janusz Czapski

    2013-12-01

    Full Text Available Latent form of mushroom catechol oxidase was activated by O,1% sodium dodecyl sulfate (SDS. Catalytic power of the latent form, calculated from the kinetic parameters was 1,8 times higher than that of active one. Salicyl hydroxamic acid (SHAM appeared as a powerful inhibitor for both active and latent forms of catechol oxidase. However, in the range of 150-250 μM SHAM the inhibitory effect for active catechol oxidase was significantly higher than that for the latent one. Non-competitive and irreversible characteristics of inhibition of latent and active catechol oxidase was calculated from kinetic data. Electrophoretic analysis followed by scanning of the gels was used. The spots' absorbance was determined from a computer image of the isoenzyme band patterns. It allowed us to estimate gels quantitatively. Presence of one additional clearly defined slow moving isoform of SDS-activated catechol oxidase, differed in the respect of 3 bands for the active and 4 bands for the total.

  9. Inactivation of urease by catechol: Kinetics and structure.

    Science.gov (United States)

    Mazzei, Luca; Cianci, Michele; Musiani, Francesco; Lente, Gábor; Palombo, Marta; Ciurli, Stefano

    2017-01-01

    Urease is a Ni(II)-containing enzyme that catalyzes the hydrolysis of urea to yield ammonia and carbamate at a rate 10(15) times higher than the uncatalyzed reaction. Urease is a virulence factor of several human pathogens, in addition to decreasing the efficiency of soil organic nitrogen fertilization. Therefore, efficient urease inhibitors are actively sought. In this study, we describe a molecular characterization of the interaction between urease from Sporosarcina pasteurii (SPU) and Canavalia ensiformis (jack bean, JBU) with catechol, a model polyphenol. In particular, catechol irreversibly inactivates both SPU and JBU with a complex radical-based autocatalytic multistep mechanism. The crystal structure of the SPU-catechol complex, determined at 1.50Å resolution, reveals the structural details of the enzyme inhibition.

  10. The role of DNA methylation in catechol-enhanced erythroid differentiation of K562 cells

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiao-Fei; Wu, Xiao-Rong; Xue, Ming; Wang, Yan; Wang, Jie; Li, Yang; Suriguga,; Zhang, Guang-Yao; Yi, Zong-Chun, E-mail: yizc@buaa.edu.cn

    2012-11-15

    Catechol is one of phenolic metabolites of benzene in vivo. Catechol is also widely used in pharmaceutical and chemical industries. In addition, fruits, vegetables and cigarette smoke also contain catechol. Our precious study showed that several benzene metabolites (phenol, hydroquinone, and 1,2,4-benzenetriol) inhibited erythroid differentiation of K562 cells. In present study, the effect of catechol on erythroid differentiation of K562 cells was investigated. Moreover, to address the role of DNA methylation in catechol-induced effect on erythroid differentiation in K562 cells, methylation levels of erythroid-specific genes were analyzed by Quantitative MassARRAY methylation analysis platform. Benzidine staining showed that exposure to catechol enhanced hemin-induced hemoglobin accumulation in K562 cells in concentration- and time-dependent manners. The mRNA expression of erythroid specific genes, including α-globin, β-globin, γ-globin, erythroid 5-aminolevulinate synthase, erythroid porphobilinogen deaminase, and transcription factor GATA-1 genes, showed a significant concentration-dependent increase in catechol-treated K562 cells. The exposure to catechol caused a decrease in DNA methylation levels at a few CpG sites in some erythroid specific genes including α-globin, β-globin and erythroid porphobilinogen deaminase genes. These results indicated that catechol improved erythroid differentiation potency of K562 cells at least partly via up-regulating transcription of some erythroid related genes, and suggested that inhibition of DNA methylation might be involved in up-regulated expression of some erythroid related genes. -- Highlights: ► Catechol enhanced hemin-induced hemoglobin accumulation. ► Exposure to catechol resulted in up-regulated expression of erythroid genes. ► Catechol reduced methylation levels at some CpG sites in erythroid genes.

  11. Biological degradation of catechol in wastewater using the sequencing continuous-inflow reactor (SCR).

    Science.gov (United States)

    Aghapour, Ali Ahmad; Moussavi, Gholamreza; Yaghmaeian, Kamyar

    2013-05-24

    Catechol is used in many industries. It can be removed from wastewater by various methods but biological processes are the most superior and commonly used technology. The SCR is a modified form of SBR used to degrade catechol. The objective of this study was to investigate the performance of SCR for biodegradation and mineralization of catechol under various inlet concentrations (630-1500 mg/L) and hydraulic retention times (HRT) (18-9 h). This study used a bench scale SCR setup to test catechol degradation. The acclimation time of biomass for catechol at degradation at 630 mg/L was 41 d. The SCR operating cycle time was 6 h and the consecutive times taken for aerating, settling and decanting were 4, 1.5 and 0.5 h, respectively. This study investigated the effects of inlet catechol concentration (630-1560 mg/L) and HRT (18-9 h). The average catechol removal efficiencies in steady-state conditions of 630, 930, 12954 and 1559 mg/L of catechol were 98.5%, 98.5%, 98.2% and 96.9% in terms catechol and 97.8%, 97.7%, 96.4% and 94.3% for COD, respectively. SCR with acclimated biomasses could effectively remove the catechol and the corresponding COD from wastewater with concentrations of up to 1560, at the loading rate of 5.38 kg COD/m3.d and at a HRT of up to 13 h. The HRT was determined as an important variable affecting catechol removal from wastewater. Reducing the HRT to below 13 h led to reduced removal of catechol and COD.

  12. Adsorption of catechol from aqueous solution by aminated hypercrosslinked polymers

    Institute of Scientific and Technical Information of China (English)

    SUN Yue; LI Xiao-tao; XU Chao; CHEN Jin-long; LI Ai-min; ZHANG Quan-xing

    2005-01-01

    Adsorption of catechol from aqueous solution with the hypercrosslinked polymeric adsorbent NDA-100 and its derivatives AH-1,AH-2 and AH-3 aminated by dimethylamine, the commercial resin Amberlite XAD-4 and weakly basic anion exchanger resin D301 was compared. It was found that the aminated hypercrosslinked resins had the highest adsorption capacities among the tested polymers. The empirical Freundlich equation was successfully employed to describe the adsorption process. Specific surface area and micropore structure of the adsorbent, in company with tertiary amino groups on matrix affected the adsorption performance towards catechol. In addition,thermodynamic study was carried out to interpret the adsorption mechanism. Kinetic study testified that the tertiary amino groups on the polymer matrix could decrease the adsorption rate and increase the adsorption apparent activation energy.

  13. A catechol biosensor based on electrospun carbon nanofibers

    Directory of Open Access Journals (Sweden)

    Dawei Li

    2014-03-01

    Full Text Available Carbon nanofibers (CNFs were prepared by combining electrospinning with a high-temperature carbonization technique. And a polyphenol biosensor was fabricated by blending the obtained CNFs with laccase and Nafion. Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR and field emission scanning electron microscope (FE-SEM were, respectively, employed to investigate the structures and morphologies of the CNFs and of the mixtures. Cyclic voltammetry and chronoamperometry were employed to study the electrocatalysis of the catechol biosensor. The results indicated that the sensitivity of the biosensor was 41 µA·mM−1, the detection limit was 0.63 µM, the linear range was 1–1310 µM and the response time was within 2 seconds, which excelled most other laccase-based biosensor reported. Furthermore, the biosensor showed good repeatability, reproducibility, stability and tolerance to interferences. This novel biosensor also demonstrated its promising application in detecting catechol in real water samples.

  14. A catechol biosensor based on electrospun carbon nanofibers

    Science.gov (United States)

    Li, Dawei; Pang, Zengyuan; Chen, Xiaodong; Luo, Lei; Cai, Yibing

    2014-01-01

    Summary Carbon nanofibers (CNFs) were prepared by combining electrospinning with a high-temperature carbonization technique. And a polyphenol biosensor was fabricated by blending the obtained CNFs with laccase and Nafion. Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscope (FE-SEM) were, respectively, employed to investigate the structures and morphologies of the CNFs and of the mixtures. Cyclic voltammetry and chronoamperometry were employed to study the electrocatalysis of the catechol biosensor. The results indicated that the sensitivity of the biosensor was 41 µA·mM−1, the detection limit was 0.63 µM, the linear range was 1–1310 µM and the response time was within 2 seconds, which excelled most other laccase-based biosensor reported. Furthermore, the biosensor showed good repeatability, reproducibility, stability and tolerance to interferences. This novel biosensor also demonstrated its promising application in detecting catechol in real water samples. PMID:24778958

  15. Computational Study on the Stacking Interaction in Catechol Complexes

    Science.gov (United States)

    Estévez, Laura; Otero, Nicolás; Mosquera, Ricardo A.

    2009-09-01

    The stability and electron density topology of catechol complexes (dimers and tetramer) were studied using the MPW1B95 functional. The QTAIM analysis shows that both dimers (face to face and C-H/π one) display a different electronic origin. The formation of the former is accompanied by a significant change in the values of atomic electron dipole and quadrupole components, flattening the most diffuse part of the electron density distribution toward the molecular plane. A small electron population transfer is observed between catechol monomers connected by C-H/π interactions, whose QTAIM characterization does not differ from that of a weak hydrogen bond. Cooperative effects in the tetramer on binding energies are small and negligible for bond properties and charge transfer. Nevertheless, they are significant on atomic electron populations.

  16. Identification of catechols as histone-lysine demethylase inhibitors

    DEFF Research Database (Denmark)

    Nielsen, Anders L; Kristensen, Line H; Stephansen, Karen B;

    2012-01-01

    in the low µM range (1, a catechol), a subset of structurally related compounds was selected and tested against a panel of HDMs. In this subset, two inhibitors (2 and 10) had comparable affinities towards KDM4C and KDM6A but no effect on PHF8. One inhibitor restored H3K9me3 levels in KDM4C transfected U2-OS...

  17. Identification of Catechol as a New Marker for Detecting Propolis Adulteration

    Directory of Open Access Journals (Sweden)

    Shuai Huang

    2014-07-01

    Full Text Available Adulteration of propolis with poplar extract is a serious issue in the bee products market. The aim of this study was to identify marker compounds in adulterated propolis, and examine the transformation of chemical components from poplar buds to propolis. The chemical profiles of poplar extracts and propolis were compared, and a new marker compound, catechol, was isolated and identified from the extracts of poplar buds. The polyphenol oxidase, catechol oxidase, responsible for catalyzing oxidation of catechol was detected in poplar buds and propolis. The results indicate catechol can be used as a marker to detect propolis adulterated with poplar extract.

  18. Defining the Catechol-Cation Synergy for Enhanced Wet Adhesion to Mineral Surfaces.

    Science.gov (United States)

    Rapp, Michael V; Maier, Greg P; Dobbs, Howard A; Higdon, Nicholas J; Waite, J Herbert; Butler, Alison; Israelachvili, Jacob N

    2016-07-27

    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.

  19. Fluorescence quenching method for the determination of catechol with gold nanoparticles and tyrosinase hybrid system

    Institute of Scientific and Technical Information of China (English)

    Martin; M.F.Choi

    2010-01-01

    The determination method of catechol by fluorescence quenching was developed.The assay was based on the combination of the unique property of gold nanoparticles with tyrosinase enzymatic reaction.In the presence of tyrosinase,the fluorescence of gold nanoparticles was quenched by catechol which can be employed to detect catechol.Under the optimal conditions,a linear range 5.0×10~(-7)-1.0×10~(-3) mol L~(-1) and a detection limit 1.0×10~(-7) mol L~(-1) of catechol were obtained.o-Quinone intermediate produ...

  20. Relative Abundance and the Relationships between Aniline,Phenol and Catechol Degraders in Fresh Water

    Institute of Scientific and Technical Information of China (English)

    MasaoNasu; NevilGOONEWARDENA; 等

    1993-01-01

    Relative abundance and relationships between aniline,phenol and catechol degraders were investigated in unpolluted and polluted fresh waters in Osaka prefectur,Japan,Phenol and catechol degraders were found more frequently compared to aniline degraders.The results indicate that these degraders were more abundant in polluted waters than in unpolluted waters.Aniline degraders isolated from the Ina River water showed a higher capability of degrading catechol than phenol.Analysis on sequence homology among these three kinds of degraders indicated a possible relationship between aniline degraders and certain strains of both catechol and phenol degraders.

  1. Aerosol formation yields from the reaction of catechol with ozone

    Science.gov (United States)

    Coeur-Tourneur, Cécile; Tomas, Alexandre; Guilloteau, Angélique; Henry, Françoise; Ledoux, Frédéric; Visez, Nicolas; Riffault, Véronique; Wenger, John C.; Bedjanian, Yuri

    The formation of secondary organic aerosol from the gas-phase reaction of catechol (1,2-dihydroxybenzene) with ozone has been studied in two smog chambers. Aerosol production was monitored using a scanning mobility particle sizer and loss of the precursor was determined by gas chromatography and infrared spectroscopy, whilst ozone concentrations were measured using a UV photometric analyzer. The overall organic aerosol yield ( Y) was determined as the ratio of the suspended aerosol mass corrected for wall losses ( Mo) to the total reacted catechol concentrations, assuming a particle density of 1.4 g cm -3. Analysis of the data clearly shows that Y is a strong function of Mo and that secondary organic aerosol formation can be expressed by a one-product gas-particle partitioning absorption model. The aerosol formation is affected by the initial catechol concentration, which leads to aerosol yields ranging from 17% to 86%. The results of this work are compared to similar studies reported in the literature.

  2. Immobilization of amphiphilic polycations by catechol functionality for antimicrobial coatings.

    Science.gov (United States)

    Han, Hua; Wu, Jianfeng; Avery, Christopher W; Mizutani, Masato; Jiang, Xiaoming; Kamigaito, Masami; Chen, Zhan; Xi, Chuanwu; Kuroda, Kenichi

    2011-04-05

    A new strategy for preparing antimicrobial surfaces by a simple dip-coating procedure is reported. Amphiphilic polycations with different mole ratios of monomers containing dodecyl quaternary ammonium, methoxyethyl, and catechol groups were synthesized by free-radical polymerization. The polymer coatings were prepared by immersing glass slides into a polymer solution and subsequent drying and heating. The quaternary ammonium side chains endow the coatings with potent antibacterial activity, the methoxyethyl side chains enable tuning the hydrophobic/hydrophilic balance, and the catachol groups promote immobilization of the polymers into films. The polymer-coated surfaces displayed bactericidal activity against Escherichia coli and Staphylococcus aureus in a dynamic contact assay and prevented the accumulation of viable E. coli, S. aureus, and Acinetobacter baumannii for up to 96 h. Atomic force microscopy (AFM) images of coating surfaces indicated that the surfaces exhibit virtually the same smoothness for all polymers except the most hydrophobic. The hydrophobic polymer without methoxyethyl side chains showed clear structuring into polymer domains, causing high surface roughness. Sum-frequency generation (SFG) vibrational spectroscopy characterization of the surface structures demonstrated that the dodecyl chains are predominantly localized at the surface-air interface of the coatings. SFG also showed that the phenyl groups of the catechols are oriented on the substrate surface. These results support our hypothesis that the adhesive or cross-linking functionality of catechol groups discourages polymer leaching, allowing the tuning of the amphiphilic balance by incorporating hydrophilic components into the polymer chains to gain potent biocidal activity.

  3. Enzymatic activity of catechol 1,2-dioxygenase and catechol 2,3-dioxygenase produced by Gordonia polyisoprenivorans

    Directory of Open Access Journals (Sweden)

    Andréa Scaramal Silva

    2012-01-01

    Full Text Available This study aimed to evaluate the environmental conditions for enzyme activity of catechol 1,2-dioxygenase (C1,2O and catechol 2,3-dioxygenase (C2,3O produced by Gordonia polyisoprenivorans in cell-free and immobilized extracts. The optimum conditions of pH, temperature, time course and effect of ions for enzyme activity were determined. Peak activity of C1,2O occurred at pH 8.0. The isolate exhibited the highest activity of C2,3O at pH 7.0 and 8.0 for the cell-free extract and immobilized extract, respectively. This isolate exhibited important characteristics such as broad range of pH, temperature and time course for enzyme activity.

  4. The effect of catechol O-methylation on radical scavenging characteristics of quercetin and luteolin, a mechanistic insight

    NARCIS (Netherlands)

    Lemanska, K.; Woude, van der H.; Szymusiak, H.; Boersma, M.G.; Gliszczynska-Swiglo, A.; Rietjens, I.M.C.M.; Tyrakowska, B.

    2004-01-01

    The biological effect of flavonoids can be modulated in vivo due to metabolism. The O-methylation of the catechol group in the molecule by catechol O-methyl transferase is one of the important metabolic pathways of flavonoids. In the present study, the consequences of catechol O-methylation for the

  5. Pathways for formation of catechol and 1,2,4-benzenetriol in rabbits

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Osamu; Seiji, Kazunori (Tohoku Rosai Hospital, Sendai (Japan) Tohoku Univ. School of Medicine, Sendai (Japan)); Ikeda, Masayuki (Tohoku Univ. School of Medicine, Sendai (Japan))

    1989-08-01

    Benzene, an established human leukemogen, was once widely used as an industrial solvent and is currently an important material for organic synthesis. Its metabolism in man and animals has also been studied extensively, and phenolic compounds were identified as major metabolites in urine after benzene exposure. One point yet to be elucidated is the pathway for formation of catechol (or 1,2-benzenediol). Early studies suggested that catechol will be formed via phenol whereas a later study failed to identify catechol in the urine of men and rabbits after oral administration methods of {sup 14}C-phenol. Sensitive HPLC methods have been recently developed in our laboratory to measure urinary phenolic metabolites and t,t-muconic acid. The methods were applied to show that phenol is not a precursor of catechol in rabbits. Evidence is also presented that 1,2,4-benzenetriol is formed only from quinol (1,4-benzenediol) and not from catechol.

  6. Synthesis of tripodal catecholates and their immobilization on zinc oxide nanoparticles

    Directory of Open Access Journals (Sweden)

    Franziska Klitsche

    2015-05-01

    Full Text Available A common approach to generate tailored materials and nanoparticles (NPs is the formation of molecular monolayers by chemisorption of bifunctional anchor molecules. This approach depends critically on the choice of a suitable anchor group. Recently, bifunctional catecholates, inspired by mussel-adhesive proteins (MAPs and bacterial siderophores, have received considerable interest as anchor groups for biomedically relevant metal surfaces and nanoparticles. We report here the synthesis of new tripodal catecholates as multivalent anchor molecules for immobilization on metal surfaces and nanoparticles. The tripodal catecholates have been conjugated to various effector molecules such as PEG, a sulfobetaine and an adamantyl group. The potential of these conjugates has been demonstrated with the immobilization of tripodal catecholates on ZnO NPs. The results confirmed a high loading of tripodal PEG-catecholates on the particles and the formation of stable PEG layers in aqueous solution.

  7. Photophysical properties of catechol axially substituted tetra-α-(pentyloxy) titanium (IV) phthalocyanine

    Science.gov (United States)

    Yu, Xinxin; Lin, Ting; Lv, Huafei; Pan, Sujuan; Wu, Shijun; Zeng, Di; Jiang, Yufeng; Wang, Yuhua; Yang, Hongqin; Huang, Yide; Peng, Yiru

    2016-10-01

    Metal phthalocyanines (MPcs) have been found to be a promising photosensitizers for photodynamic therapy (PDT) of cancers and non-cancer diseases. Nevertheless, phthalocyanines are substantially limited in clinical applications owing to their poor solubility, aggregation and insufficient selectivity for cancer cells. Catechol is an important pharmaceutical intermediate, playing important in vivo biological activity in medicine. Using catechol (pyrocatechin) as axial ligands, utilizing of the pharmaceutical effect of catechins, could improve the bioavailability, and achieve synergistic therapeutic effect in PDT. To address these issues, a novel catechol axially substituted tetra-α-(pentyloxy) titanium(IV) (TiPc(OC5H11)4-Catechol) was synthesized. The structure of TiPc(OC5H11)4-Catechol was characterized by elemental analysis, IR, 1HNMR and MS methods. The photophysical properties of TiPc(OC5H11)4 and TiPc(OC5H11)4-Catechol have been studied by UV/Vis and steady-state fluorescence spectra. After being axially substituted with catechin groups, no obviously intensity and position of maximum wavelength in Q-band of TiPc(OC5H11)4 and TiPc(OC5H11)4-Catechol were observed. The fluorescence intensity of TiPc(OC5H11)4 was stronger than that of TiPc(OC5H11)4-Catechol, but the fluorescence lifetime of TiPc(OC5H11)4-Catechol was longer than that of TiPc(OC5H11)4. TiPc(OC5H11)4-Catechol may be considered as a promising photosensitizer for PDT.

  8. Hypnotizability and Catechol-O-Methyltransferase (COMT polymorphysms in Italians

    Directory of Open Access Journals (Sweden)

    Silvano ePresciuttini

    2014-01-01

    Full Text Available Higher brain dopamine content depending on lower activity of Catechol-O-Methyltransferase (COMT in subjects with high hypnotisability scores (highs has been considered responsible for their attentional characteristics. However, the results of the previous genetic studies on association between hypnotisability and the Catechol-O-Methyltransferase (COMT single nucleotide polymorphism (SNP rs4680 (Val158Met were inconsistent. Here, we used a selective genotyping approach to re-evaluate the association between hypnotisability and COMT in the context of a two-SNP haplotype analysis, considering not only the Val158Met polymorphism, but also the closely located rs4818 SNP. An Italian sample of 53 highs, 49 low hypnotizable subjects (lows and 57 controls, were genotyped for a segment of 805 bp of the COMT gene, including Val158Met and the closely located rs4818 SNP. Our selective genotyping approach had 97.1% power to detect the previously reported strongest association at the significance level of 5%. We found no evidence of association at the SNP, haplotype and diplotype levels. Thus, our results challenge the dopamine-based theory of hypnosis and indirectly support recent neuropsychological and neurophysiological findings reporting the lack of any association between hypnotisability and focused attention abilities.

  9. Alkylation of Catechol with tert-Butyl Alcohol Catalyzed by Mesoporous Acidic Montmorillonite Heterostructure Catalysts

    Institute of Scientific and Technical Information of China (English)

    周春晖; 葛忠华; 李小年; 童东绅; 李庆伟; 郭红强

    2004-01-01

    The liquid phase alkylation of catechol with tert-butyl alcohol to produce 4-tert-butyl catechol (4-TBC) was carried out over MCM-41, HZSM-5, H-exchanged montmorillonite and novel acidic porous montmorillonite heterostructures (PMHs). Upon all catalysts tested, 4-TBC is the main product and 3-tert-butyl catechol (3-TBC) and 3,5-di-tert-butyl catechol are the side products. The synthetic PMHs showed higher conversion of catechol and better selectivity to 4-TBC compared to other solid acid catalysts tested. Over the PMHs derived from H-exchanged montmorillonite through template extraction processes, the suitable reaction temperature is ca 410 K, the ratio of catechol to tert-butyl alcohol is 1:2. Increasing the amount of catalyst (lower weight hourly space velocity) can improve the conversion of catechol and influence the selectivity slightly. The reasonable reaction time is ca 8 h.The type and strength of acidity of H-montmorillonite and PMH were determined by pyridine adsorption FT-IR and ammonia temperature-programmed desorption techniques. The medium and strong acid sites are conducive to producing 4-TBC and the weak acid sites to facilitating the 3-TBC formation. The differences between the PMHs from calcination and those fi'om extraction are attributed to proton migration and acidity change in the gallery surface.

  10. Joining Two Natural Motifs: Catechol-Containing Poly(phosphoester)s.

    Science.gov (United States)

    Becker, Greta; Ackermann, Lisa-Maria; Schechtel, Eugen; Klapper, Markus; Tremel, Wolfgang; Wurm, Frederik R

    2017-02-14

    Numerous catechol-containing polymers, including biodegradable polymers, are currently heavily discussed for modern biomaterials. However, there is no report combining poly(phosphoester)s (PPEs) with catechols. Adhesive PPEs have been prepared via acyclic diene metathesis polymerization. A novel acetal-protected catechol phosphate monomer was homo- and copolymerized with phosphoester comonomers with molecular weights up to 42000 g/mol. Quantitative release of the catechols was achieved by careful hydrolysis of the acetal groups without backbone degradation. Degradation of the PPEs under basic conditions revealed complete and statistical degradation of the phosphotri- to phosphodiesters. In addition, a phosphodiester monomer with an adhesive P-OH group and no protective group chemistry was used to compare the binding to metal oxides with the multicatechol-PPEs. All PPEs can stabilize magnetite particles (NPs) in polar solvents, for example, methanol, due to the binding of the phosphoester groups in the backbone to the particles. ITC measurements reveal that multicatechol PPEs exhibit a higher binding affinity to magnetite NPs compared to PPEs bearing phosphodi- or phosphotriesters as repeating units. In addition, the catechol-containing PPEs were used to generate organo- and hydrogels by oxidative cross-linking, due to cohesive properties of catechol groups. This unique combination of two natural adhesive motives, catechols and phosphates, will allow the design of novel future gels for tissue engineering applications or novel degradable adhesives.

  11. Mussel-mimetic self-healing polyaspartamide derivative gel via boron-catechol interactions

    Directory of Open Access Journals (Sweden)

    B. Wang

    2015-09-01

    Full Text Available The catechol group from catechol of 3,4-dihydroxyphenethylamine (DOP, dopamine has the ability to interact with metal ions to form non-covalent bonds in polymer chains. In this study, a novel kind of mussel-inspired copolymer, dopamine-conjugated poly(hydroxyethyl aspartamide, polyAspAm(DOP/EA, was synthesized and its interaction with boric acid (H3BO3 to form a cross-linked gel via boron-catechol coordinative binding was investigated. The copolymer was designed to contain a pH responsive adhesive catechol group, which reversibly underwent gelation through the metalcatechol binding, as proved by UV-Vis spectroscopy. When the pH is increased from acidic conditions to a specified pH (pH > 9, the B(OH3 is considered to have a functionality of two to bind catechols, leading to bis-complexes. In addition, the reversibility of the boron-catechol bonds provides self-healing characteristics to the polyAspAm gels. The rheological results showed that boron-catechol coordination could lead to quick and full recovery after the fracture of a gel specimen. This novel pH-responsive and self-healing gel system has potential in various applications including smart hydrogels, medical adhesives, and sealants.

  12. Zn-edta degradation by catechol-driven fenton reaction

    Directory of Open Access Journals (Sweden)

    Claudia Oviedo

    2012-01-01

    Full Text Available Zn-EDTA degradabilty by catechol-driven Fenton reaction was studied. Response surface methodology central composite design was employed to maximize this complex degradation. Theoretical speciation calculations were in good agreement with the experimental results. Fenton and Fenton type treatments are typically thought to be applicable only in the highly acidic range, representing a major operational constraint. Interestingly, at optimized concentrations, this CAT-driven Fenton reaction at pH 5.5 achieved 100% Zn-EDTA degradation; 60% COD and 17% TOC removals, using tiny amounts of CAT (50 µM, Fe(III (445 µM and H2O2 (20 mM with no evident ferric sludge.

  13. Quinone Reductase 2 Is a Catechol Quinone Reductase

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Yue; Buryanovskyy, Leonid; Zhang, Zhongtao (NYMEDCO)

    2008-09-05

    The functions of quinone reductase 2 have eluded researchers for decades even though a genetic polymorphism is associated with various neurological disorders. Employing enzymatic studies using adrenochrome as a substrate, we show that quinone reductase 2 is specific for the reduction of adrenochrome, whereas quinone reductase 1 shows no activity. We also solved the crystal structure of quinone reductase 2 in complexes with dopamine and adrenochrome, two compounds that are structurally related to catecholamine quinones. Detailed structural analyses delineate the mechanism of quinone reductase 2 specificity toward catechol quinones in comparison with quinone reductase 1; a side-chain rotational difference between quinone reductase 1 and quinone reductase 2 of a single residue, phenylalanine 106, determines the specificity of enzymatic activities. These results infer functional differences between two homologous enzymes and indicate that quinone reductase 2 could play important roles in the regulation of catecholamine oxidation processes that may be involved in the etiology of Parkinson disease.

  14. Metal salts of alkyl catechol dithiophosphoric acids and oil compositions containing the salts

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, E.S.; Liston, T.V.

    1988-03-08

    Metal salts of alkyl catechol esters of dithiophosphoric acid suitable as additives in oil compositions are disclosed in this patent. Oil compositions containing the salts of such esters show improved extreme pressure/anti-wear and anit-oxidant properties.

  15. Thermally stable drilling fluid additive comprised of a copolymer of catechol-based monomer

    Energy Technology Data Exchange (ETDEWEB)

    Patel, A.D.

    1986-06-17

    A water soluble polymer is described having thermal stability and exhibiting utility as an aqueous drilling fluid additive comprising: (a) a major portion of a catechol based monomer; (b) a minor portion of a dicarboxylic acid monomer.

  16. A novel palygorskite-modified carbon paste amperometric sensor for catechol determination

    Energy Technology Data Exchange (ETDEWEB)

    Kong Yong [School of Chemistry and Chemical Engineering, Changzhou University, No. 1 Gehu Road, Changzhou 213164, Jiangsu Province (China); Key Lab of Analytical Chemistry for Life Science, Ministry of Education, Nanjing University, Nanjing 210093 (China); Chen Xiaohui; Wang Wenchang [School of Chemistry and Chemical Engineering, Changzhou University, No. 1 Gehu Road, Changzhou 213164, Jiangsu Province (China); Chen Zhidong, E-mail: czd_chen@yahoo.com.cn [School of Chemistry and Chemical Engineering, Changzhou University, No. 1 Gehu Road, Changzhou 213164, Jiangsu Province (China)

    2011-03-04

    A palygorskite-modified carbon paste electrode (CPE) was constructed using graphite powder mixed with palygorskite particles. Compared with the unmodified CPE, the resulting palygorskite-modified CPE remarkably increases the peak currents of catechol, and greatly lowers the peak potential separation. Therefore, the palygorskite exhibits catalytic activity to catechol and significantly improves the determining sensitivity. The electrocatalytic activity of palygorskite is attributed to its high adsorption capability and the -OH groups on its surface, which plays an important role in the electron transfer between the modified CPE and the catechol in the solution. The sensor shows a linear response range between 5 and 100 {mu}M catechol with a correlation coefficient of 0.998. The detection limit was calculated as 0.57 {mu}M (s/n = 3).

  17. Protein-responsive assemblies from catechol-metal ion supramolecular coordination.

    Science.gov (United States)

    Yuan, C; Chen, J; Yu, S; Chang, Y; Mao, J; Xu, Y; Luo, W; Zeng, B; Dai, L

    2015-03-21

    Supramolecular self-assembly driven by catechol-metal ion coordination has gained great success in the fabrication of functional materials including adhesives, capsules, coatings and hydrogels. However, this route has encountered a great challenge in the construction of nanoarchitectures in the absence of removable templates, because of the uncontrollable crosslinking of catechol-metal ion coordination. Herein, we show that a supramolecular approach, combining both catechol-metal ion coordination and polymer self-assembly together, can organize polymers into hybrid nanoassemblies ranging from solid particles, homogeneous vesicles to Janus vesicles. Without the introduction of a specific binding ligand or complicated molecular design, these assemblies can totally disassemble in response to proteins. UV/vis absorption, fluorescence quenching and recovery investigations have confirmed that proteins can seize metal ions from the hybrid nanoassemblies, thus causing the degradation of catechol-metal ion coordination networks.

  18. BIOLOGICAL ADHESIVES. Adaptive synergy between catechol and lysine promotes wet adhesion by surface salt displacement.

    Science.gov (United States)

    Maier, Greg P; Rapp, Michael V; Waite, J Herbert; Israelachvili, Jacob N; Butler, Alison

    2015-08-01

    In physiological fluids and seawater, adhesion of synthetic polymers to solid surfaces is severely limited by high salt, pH, and hydration, yet these conditions have not deterred the evolution of effective adhesion by mussels. Mussel foot proteins provide insights about adhesive adaptations: Notably, the abundance and proximity of catecholic Dopa (3,4-dihydroxyphenylalanine) and lysine residues hint at a synergistic interplay in adhesion. Certain siderophores—bacterial iron chelators—consist of paired catechol and lysine functionalities, thereby providing a convenient experimental platform to explore molecular synergies in bioadhesion. These siderophores and synthetic analogs exhibit robust adhesion energies (E(ad) ≥-15 millijoules per square meter) to mica in saline pH 3.5 to 7.5 and resist oxidation. The adjacent catechol-lysine placement provides a "one-two punch," whereby lysine evicts hydrated cations from the mineral surface, allowing catechol binding to underlying oxides.

  19. Lycopene and beta-carotene ameliorate catechol estrogen-mediated DNA damage

    OpenAIRE

    2005-01-01

    The consumption of fruits and vegetables is associated with a reduced risk of various ailments, including cancer and cardiovascular diseases. Carotenoids, such as lycopene and beta-carotene, are natural constituents of edible plants and may protect against disease. In this study, the influence of lycopene and beta-carotene on DNA damage caused by catechol-estrogens in vitro is examined. One possible mechanism by which catechol estrogens such as 4-hydroxyestradiol (4-OHE2) and 2-hydroxyestradi...

  20. Removing Dissolved Silica from Waste Water with Catechol and Active Carbon

    Energy Technology Data Exchange (ETDEWEB)

    Sasan, Koroush [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Nanoscale Sciences Dept.; Brady, Patrick [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Advanced Nuclear Energy Program; Krumhansl, James L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Geosciences Dept.; Nenoff, Tina M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Physical Chemical and Nano Sciences Center

    2017-01-01

    Fresh water scarcity is going to be a global great challenge in the near future because of the increasing population. Our water resources are limited and, hence, water treatment and recycling methods are the only alternatives for fresh water procurement in the upcoming decades. Water treatment and recycling methods serve to remove harmful or problematic constituents from ground, surface and waste waters prior to its consumption, industrial supply, or other uses. Scale formation in industrial and domestic installations is still an important problem during water treatment. In water treatment, silica scaling is a real and constant concern for plant operations. The focus of this study is on the viability of using a combination of catechol and active carbon to remove dissolved silica from concentrated cooling tower water (CCTW). Various analytical methods, such as ICP-MS and UV-vis, were used to understand the structure-property relationship between the material and the silica removal results. UV-Vis indicates that catechol can react with silica ions and form a silica-catecholate complex. The speciation calculation of catechol and silica shows that catechol and silica bind in the pH range of 8 – 10; there is no evidence of linkage between them in neutral and acidic pHs. The silica removal results indicate that using ~4g/L of catechol and 10g/L active carbon removes up to 50% of the dissolved silica from the CCTW.

  1. A Novel Mechanism for Adenylyl Cyclase Inhibition from the Crystal Structure of its Complex with Catechol Estrogen

    Energy Technology Data Exchange (ETDEWEB)

    Steegborn,C.; Litvin, T.; Hess, K.; Capper, A.; Taussig, R.; Buck, J.; Levin, L.; Wu, H.

    2005-01-01

    Catechol estrogens are steroid metabolites that elicit physiological responses through binding to a variety of cellular targets. We show here that catechol estrogens directly inhibit soluble adenylyl cyclases and the abundant trans-membrane adenylyl cyclases. Catechol estrogen inhibition is non-competitive with respect to the substrate ATP, and we solved the crystal structure of a catechol estrogen bound to a soluble adenylyl cyclase from Spirulina platensis in complex with a substrate analog. The catechol estrogen is bound to a newly identified, conserved hydrophobic patch near the active center but distinct from the ATP-binding cleft. Inhibitor binding leads to a chelating interaction between the catechol estrogen hydroxyl groups and the catalytic magnesium ion, distorting the active site and trapping the enzyme substrate complex in a non-productive conformation. This novel inhibition mechanism likely applies to other adenylyl cyclase inhibitors, and the identified ligand-binding site has important implications for the development of specific adenylyl cyclase inhibitors.

  2. 1, 4-Pyrone Effects on O-H Bond Dissociation Energies of Catechols in Flavonoids: A Density Functional Theory Study

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Through B3LYP/6-31G** calculations, the 1, 4-pyrone effects on O-H bond dissociation energies (BDEs) of catechols in rings A or B of flavonoids were investigated. For the catechol in ring A, although 1, 4-pyrone enlarged the conjugation system, its electron-withdrawing property increased the O-H BDE 3 ( 4.184 kJ/mol compared with that of catechol. However, for the catechol in ring B, 1, 4-pyrone was poorly conjugated with the moiety, and therefore, had little effect on the O-H BDE.

  3. Characterization of catechol 2,3-dioxygenase from Planococcus sp. strain S5 induced by high phenol concentration.

    Science.gov (United States)

    Hupert-Kocurek, Katarzyna; Guzik, Urszula; Wojcieszyńska, Danuta

    2012-01-01

    This study aimed at characterization of a new catechol 2,3-dioxygenase isolated from a Gram-positive bacterium able to utilize phenol as the sole carbon and energy source. Planococcus sp. strain S5 grown on 1 or 2 mM phenol showed activity of both a catechol 1,2- and catechol 2,3-dioxygenase while at a higher concentrations of phenol only catechol 2,3-dioxygenase activity was observed. The enzyme was optimally active at 60°C and pH 8.0. Kinetic studies showed that the K(m) and V(max) of the enzyme were 42.70 µM and 329.96 mU, respectively. The catechol 2,3-dioxygenase showed the following relative meta-cleavage activities for various catechols tested: catechol (100%), 3-methylcatechol (13.67%), 4-methylcatechol (106.33%) and 4-chlorocatechol (203.80%). The high reactivity of this enzyme towards 4-chlorocatechol is different from that observed for other catechol 2,3-dioxygenases. Nucleotide sequencing and homology search revealed that the gene encoding the S5 catechol 2,3-dioxygenase shared the greatest homology with the known genes encoding isoenzymes from Gram-negative Pseudomonas strains.

  4. Heterogeneous Reactions of Surface-Adsorbed Catechol: A Comparison of Tropospheric Aerosol Surrogates

    Science.gov (United States)

    Hinrichs, R. Z.; Woodill, L. A.

    2009-12-01

    Surface-adsorbed organics can alter the chemistry of tropospheric solid-air interfaces, such as aerosol and ground level surfaces, thereby impacting photochemical cycles and altering aerosol properties. The nature of the surface can also influence the chemistry of the surface-adsorbed organic. We employed diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) to monitor the adsorption of gaseous catechol on several tropospheric aerosol surrogates and to investigate the subsequent reactivity of adsorbed-catechol with nitrogen dioxide and, in separate preliminary experiments, ozone. Graphite, kaolinite, and sodium halide (NaF, NaCl, NaBr) powders served as carbonaceous, mineral and sea salt aerosol surrogates, respectively. Broad OH stretching bands for adsorbed catechol shifted to lower wavenumber with peak frequencies following the trend NaBr > NaCl > NaF ≈ kaolinite, consistent with the increasing basicity of the halide anions and basic Brønsted sites on kaolinite. The dark heterogeneous reaction of NO2 with NaCl-adsorbed catechol at relative humidity (RH) 4-nitrocatechol and oxidation forming 1,2-benzoquinone and the ring cleavage product muconic acid, with product yields of 88%, 8%, and 4%, respectively. 4-Nitrocatechol was the dominant product for catechol adsorbed on NaF and kaolinite, while NaBr-adsorbed catechol produced less 4-nitrocatechol and more 1,2-benzoquinone and muconic acid. For all three sodium halides, the reactions of NO2 with adsorbed catechol were orders of magnitude faster than between NO2 and each NaX substrate. 4-Nitrocatechol rates and product yields were consistent with the relative ability of each substrate to enhance the deprotonated nature of adsorbed-catechol. Increasing the relative humidity caused the rate of each product channel to decrease and also altered the product branching ratios. Most notably, 1,2-benzoquinone formation decreased significantly even at 13% RH. The dramatic reactivity of surface

  5. Inhibition of human catechol-O-methyltransferase (COMT)-mediated O-methylation of catechol estrogens by major polyphenolic components present in coffee.

    Science.gov (United States)

    Zhu, Bao Ting; Wang, Pan; Nagai, Mime; Wen, Yujing; Bai, Hyoung-Woo

    2009-01-01

    In the present study, we investigated the inhibitory effect of three catechol-containing coffee polyphenols, chlorogenic acid, caffeic acid and caffeic acid phenethyl ester (CAPE), on the O-methylation of 2- and 4-hydroxyestradiol (2-OH-E(2) and 4-OH-E(2), respectively) catalyzed by the cytosolic catechol-O-methyltransferase (COMT) isolated from human liver and placenta. When human liver COMT was used as the enzyme, chlorogenic acid and caffeic acid each inhibited the O-methylation of 2-OH-E(2) in a concentration-dependent manner, with IC(50) values of 1.3-1.4 and 6.3-12.5 microM, respectively, and they also inhibited the O-methylation of 4-OH-E(2), with IC(50) values of 0.7-0.8 and 1.3-3.1 microM, respectively. Similar inhibition pattern was seen with human placental COMT preparation. CAPE had a comparable effect as caffeic acid for inhibiting the O-methylation of 2-OH-E(2), but it exerted a weaker inhibition of the O-methylation of 4-OH-E(2). Enzyme kinetic analyses showed that chlorogenic acid and caffeic acid inhibited the human liver and placental COMT-mediated O-methylation of catechol estrogens with a mixed mechanism of inhibition (competitive plus noncompetitive). Computational molecular modeling analysis showed that chlorogenic acid and caffeic acid can bind to human soluble COMT at the active site in a similar manner as the catechol estrogen substrates. Moreover, the binding energy values of these two coffee polyphenols are lower than that of catechol estrogens, which means that coffee polyphenols have higher binding affinity for the enzyme than the natural substrates. This computational finding agreed perfectly with our biochemical data.

  6. Hypnotizability and Catechol-O-Methyltransferase (COMT) polymorphysms in Italians

    Science.gov (United States)

    Presciuttini, Silvano; Gialluisi, Alessandro; Barbuti, Serena; Curcio, Michele; Scatena, Fabrizio; Carli, Giancarlo; Santarcangelo, Enrica L.

    2014-01-01

    Higher brain dopamine content depending on lower activity of Catechol-O-Methyltransferase (COMT) in subjects with high hypnotizability scores (highs) has been considered responsible for their attentional characteristics. However, the results of the previous genetic studies on association between hypnotizability and the COMT single nucleotide polymorphism (SNP) rs4680 (Val158Met) were inconsistent. Here, we used a selective genotyping approach to re-evaluate the association between hypnotizability and COMT in the context of a two-SNP haplotype analysis, considering not only the Val158Met polymorphism, but also the closely located rs4818 SNP. An Italian sample of 53 highs, 49 low hypnotizable subjects (lows), and 57 controls, were genotyped for a segment of 805 bp of the COMT gene, including Val158Met and the closely located rs4818 SNP. Our selective genotyping approach had 97.1% power to detect the previously reported strongest association at the significance level of 5%. We found no evidence of association at the SNP, haplotype, and diplotype levels. Thus, our results challenge the dopamine-based theory of hypnosis and indirectly support recent neuropsychological and neurophysiological findings reporting the lack of any association between hypnotizability and focused attention abilities. PMID:24431998

  7. Simultaneous determination of hydroquinone and catechol at gold nanoparticles mesoporous silica modified carbon paste electrode.

    Science.gov (United States)

    Tashkhourian, J; Daneshi, M; Nami-Ana, F; Behbahani, M; Bagheri, A

    2016-11-15

    A new electrochemical sensor based on gold nanoparticles mesoporous silica modified carbon paste electrode (AuNPs-MPS) was developed for simultaneous determination of hydroquinone and catechol. Morphology and structure of the AuNPs-MPS were characterized by transmission electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. The electrochemical behavior of hydroquinone and catechol were investigated using square wave voltammetry and the results indicate that the electrochemical responses are improved significantly at the modified electrode. The observed oxidative peaks separation of about 120mV made possible the simultaneous determination of hydroquinone and catechol in their binary-mixture. Under the optimized condition, a linear dynamic range of 10.0μM-1.0mM range for hydroquinone with the detection limit of 1.2μM and from 30.0μM-1.0mM for catechol with the detection limit of 1.1μM were obtained. The applicability of the method was demonstrated by the recovery studies of hydroquinone and catechol in spiked tap water samples.

  8. Electrocatalytic Efficiency Analysis of Catechol Molecules for NADH Oxidation during Nanoparticle Collision.

    Science.gov (United States)

    Zhao, Li-Jun; Qian, Ruo-Can; Ma, Wei; Tian, He; Long, Yi-Tao

    2016-09-06

    Electrocatalysis of molecules is a hot research topic in biological and energy-related chemistry. Here, we develop a new system to study the electrocatalytic efficiency of a single catechol molecule for NADH oxidation by single functionalized nanoparticle collision at ultramicroelectrodes (UMEs). The proposed system is composed of gold nanoparticles (AuNPs) functionalized with catechol molecules and a carbon-fiber ultramicroelectrode. In the absence of NADH, when a functionalized AuNP collides with an UME at a suitable voltage, a small current spike is generated due to the oxidation of catechol molecules modified on the surface of AuNP. In the presence of NADH, the current spike is significantly amplified by the combined effects of the oxidation and electrocatalysis for NADH of catechol molecules. By analyzing the variations of the average peak charges and durations without or with NADH, we calculate that around five thousands NADH molecules could be catalyzed per second by a single catechol molecule, suggesting the successful establishment of this novel catalytic system. Thus, the proposed strategy could be used as a promising platform for research of other molecular electrocatalytic systems.

  9. Investigation on the Electrochemical Polymerization of Catechol by Means of Rotating Ring—disk Electrode

    Institute of Scientific and Technical Information of China (English)

    孔泳; 穆绍林

    2003-01-01

    The electrolysis of catechol was studied in the pH values of 1 to 10. The results from the rotating ring-disk electrode (RRDE) experiments show that at low pH values,the electrochemical polymerization of catechol was performed by one step,and at higher pH values,the electrochemical polymerization of catechol was carried out by two steps,i.e.oxidation of catechol and followed by polymerization.The intermediates generated at the disk were detected at the ring electrode in the ring potential region of -0.2 to 0 V(vs.Ag/AgCl).One of reasons for the decrease in the ratio of ir to id with increasing the ring potential is caused by formation of positively charged intermediates at the disk electrode.This ratio increases with increasing the rotation rate of the RRDE,which indicates that the intermediates are not stable.A shielding effect during polymerization of catechol was observed when the ring potential was set at 0.1 V (vs.Ag/AgCl).The electron spin resonance(ESR) of polycatechol show that polycatechol possesses unpaired electrons.The images of polycatechol films synthesized at differentconditions are described.

  10. Surface Complexation at the TiO(2) (anatase)/Aqueous Solution Interface: Chemisorption of Catechol.

    Science.gov (United States)

    Rodríguez; Blesa; Regazzoni

    1996-01-15

    Catechol adsorbs at the TiO(2) (anatase)/aqueous solution interface forming inner-sphere surface complexes. The UV-visible differential reflectance spectrum of surface titanium-catecholate complexes presents a band centered at 420 nm which corresponds to the ligand to metal charge transfer transition within the surface complexes. At pH values below pK(a1), the surface excess of catechol is almost insensitive toward pH and presents a Langmuirian dependence with the concentration of uncomplexed catechol. The ratio Gamma(max):N(S) (N(S) being the measured density of available OH surface groups) indicates a prevailing 1 to 2 ligand exchange adsorption stoichiometry. In the range pH >/= pK(a1), the catechol surface excess decreases markedly with increasing pH. Formation of 1 to 1 surface complexes produces an excess of negative surface charge that is revealed by the shift of the iep to lower pH values. The reported data, which are supplemented with information on the charging behavior of TiO(2) suspended in indifferent electrolyte solutions, are interpreted in terms of the multi-site surface complexation model. In this model, two types of surface OH groups are considered: identical withTiOH(1/3-) and identical withOH(1/3+). Although both surface groups undergo protonation-deprotonation reactions, only identical withTiOH(1/3-) are prone to chemisorption.

  11. A natural small molecule, catechol, induces c-Myc degradation by directly targeting ERK2 in lung cancer.

    Science.gov (United States)

    Lim, Do Young; Shin, Seung Ho; Lee, Mee-Hyun; Malakhova, Margarita; Kurinov, Igor; Wu, Qiong; Xu, Jinglong; Jiang, Yanan; Dong, Ziming; Liu, Kangdong; Lee, Kun Yeong; Bae, Ki Beom; Choi, Bu Young; Deng, Yibin; Bode, Ann; Dong, Zigang

    2016-06-07

    Various carcinogens induce EGFR/RAS/MAPK signaling, which is critical in the development of lung cancer. In particular, constitutive activation of extracellular signal-regulated kinase 2 (ERK2) is observed in many lung cancer patients, and therefore developing compounds capable of targeting ERK2 in lung carcinogenesis could be beneficial. We examined the therapeutic effect of catechol in lung cancer treatment. Catechol suppressed anchorage-independent growth of murine KP2 and human H460 lung cancer cell lines in a dose-dependent manner. Catechol inhibited ERK2 kinase activity in vitro, and its direct binding to the ERK2 active site was confirmed by X-ray crystallography. Phosphorylation of c-Myc, a substrate of ERK2, was decreased in catechol-treated lung cancer cells and resulted in reduced protein stability and subsequent down-regulation of total c-Myc. Treatment with catechol induced G1 phase arrest in lung cancer cells and decreased protein expression related to G1-S progression. In addition, we showed that catechol inhibited the growth of both allograft and xenograft lung cancer tumors in vivo. In summary, catechol exerted inhibitory effects on the ERK2/c-Myc signaling axis to reduce lung cancer tumor growth in vitro and in vivo, including a preclinical patient-derived xenograft (PDX) model. These findings suggest that catechol, a natural small molecule, possesses potential as a novel therapeutic agent against lung carcinogenesis in future clinical approaches.

  12. Enhancement by catechols of hydroxyl-radical formation in the presence of ferric ions and hydrogen peroxide.

    Science.gov (United States)

    Iwahashi, H; Morishita, H; Ishii, T; Sugata, R; Kido, R

    1989-03-01

    The effect of caffeic acid, a kind of catechol, on the Fenton reaction was examined by using the ESR spin trapping technique. Caffeic acid enhanced the formation of hydroxyl radicals in the reaction mixture, which contained caffeic acid, hydrogen peroxide, ferric chloride, EDTA, and potassium phosphate buffer. Chlorogenic acid, which is an ester of caffeic acid with quinic acid, also stimulated the formation of the hydroxyl radicals. Quinic acid did not stimulate the reaction, suggesting that the catechol moiety in chlorogenic acid is essential to the enhancement of the hydroxyl-radical formation. Indeed, other catechols and related compounds such as pyrocatechol, gallic acid, dopamine, and noradrenaline effectively stimulated the formation of the hydroxyl radicals. The above results confirm the idea that the catechol moiety is essential to the enhancement. Ferulic acid, 4-hydroxy-3-methoxybenzoic acid, and salicylic acid had no effect on the formation of the hydroxyl radicals. The results indicate that the enhancement by the catechols of the formation of hydroxyl radicals is diminished if a methyl ester is formed at the position of the hydroxyl group of the catechol. In the absence of iron chelators such as EDTA, DETAPAC, desferrioxamine, citrate, and ADP, formation of hydroxyl radicals was not detected, suggesting that chelators are essential to the reaction. The enhancement of the formation of hydroxyl radicals is presumably due to the reduction of ferric ions by the catechols. Thus, the catechols may exert deleterious effects on biological systems if chelators such as EDTA, DETAPAC, desferrioxamine, citrate, and ADP are present.

  13. A natural small molecule, catechol, induces c-Myc degradation by directly targeting ERK2 in lung cancer

    Science.gov (United States)

    Lim, Do Young; Shin, Seung Ho; Lee, Mee-Hyun; Malakhova, Margarita; Kurinov, Igor; Wu, Qiong; Xu, Jinglong; Jiang, Yanan; Dong, Ziming; Liu, Kangdong; Lee, Kun Yeong; Bae, Ki Beom; Choi, Bu Young; Deng, Yibin; Bode, Ann; Dong, Zigang

    2016-01-01

    Various carcinogens induce EGFR/RAS/MAPK signaling, which is critical in the development of lung cancer. In particular, constitutive activation of extracellular signal-regulated kinase 2 (ERK2) is observed in many lung cancer patients, and therefore developing compounds capable of targeting ERK2 in lung carcinogenesis could be beneficial. We examined the therapeutic effect of catechol in lung cancer treatment. Catechol suppressed anchorage-independent growth of murine KP2 and human H460 lung cancer cell lines in a dose-dependent manner. Catechol inhibited ERK2 kinase activity in vitro, and its direct binding to the ERK2 active site was confirmed by X-ray crystallography. Phosphorylation of c-Myc, a substrate of ERK2, was decreased in catechol-treated lung cancer cells and resulted in reduced protein stability and subsequent down-regulation of total c-Myc. Treatment with catechol induced G1 phase arrest in lung cancer cells and decreased protein expression related to G1-S progression. In addition, we showed that catechol inhibited the growth of both allograft and xenograft lung cancer tumors in vivo. In summary, catechol exerted inhibitory effects on the ERK2/c-Myc signaling axis to reduce lung cancer tumor growth in vitro and in vivo, including a preclinical patient-derived xenograft (PDX) model. These findings suggest that catechol, a natural small molecule, possesses potential as a novel therapeutic agent against lung carcinogenesis in future clinical approaches. PMID:27167001

  14. A DFT Study on Intramolecular Hydrogen Bond in Substituted Catechols and Their Radicals

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Density functional theory (DFT) at B3LYP/6-31G(d,p) level was employed to calculate intramolecular hydrogen bond enthalpies (HIHB), O-H charge differences, O-H bond lengths and bond orders for various substituted catechols and their radicals generated after H-abstraction. It was found that although the charge difference between hydrogen-bonded H and O played a role in determining HIHB, HIHB was mainly governed by the hydrogen bond length. As the oxygen-centered radical has great tendency to form a chemical bond with the H atom, hydrogen bond lengths in catecholic radicals are systematically shorter than those in catechols. Hence, the HIHB for the former are higher than those for the latter.

  15. Direction-dependent intermolecular interactions: catechol on TiO2(110)-1×1

    Science.gov (United States)

    Li, Shao-Chun; Diebold, Ulrike

    2009-08-01

    The adsorption of a submonolayer of catechol (C6H6O2) on the rutile TiO2(110)-1×1 surface has been investigated by Scanning Tunneling Microscopy (STM). The catechol molecules are preferentially adsorbed on the surface 5-fold coordinated Ti4+ sites, and occupy two neighboring lattice Ti sites. No preference for adsorption at surface step edges is observed at room temperature. A statistical analysis of intermolecular distances demonstrates that the interaction between the molecules strongly depends on the surface crystallographic direction: catechol molecules exhibit attractive interaction along [1-1 0], while they repel each other along the [001] direction. The attractive interaction is proposed to be caused by the coupling of π bonding electrons and the repulsive interaction is possibly mediated by substrate.

  16. Effect of β-cyclodextrin on intra and intermolecular Michael addition of some catechol derivatives

    Science.gov (United States)

    Khalafi, Lida; Rafiee, Mohammad; Fathi, Sahar

    2014-01-01

    The oxidation reactions of catechol, dopamine and epinephrine have been studied in the absence and presence of N-methylaniline by UV-Vis. Spectrophotometry. A variety of reaction pathways (inter and intramolecular reactions) that followed by this oxidation have been observed depending on the nature of catechol derivatives. The observed homogeneous rate constants of the reactions were estimated by fitting the absorption time profiles for each reaction. The effect of β-cyclodextrin and its inclusion complex has also been studied on the chosen reactions. The formation constants of the complexes of catechol, dopamine and epinephrine with β-cyclodextrin as well as the rate constants of the reactions of free and complexed forms have been obtained by fitting the absorption-time spectra to a proposed kinetic-equilibrium model.

  17. Remarkably enhanced adhesion of coherently aligned catechol-terminated molecules on ultraclean ultraflat gold nanoplates

    Science.gov (United States)

    Lee, Miyeon; Park, Changjun; Lee, Hyoban; Kim, Hongki; Kim, Sang Youl; In, Insik; Kim, Bongsoo

    2016-11-01

    We report the characterization and formation of catechol-terminated molecules immobilized on gold nanoplates (Au NPLs) using N-(3,4-dihydroxyphenethyl)-2-mercaptoacetamide (Cat-EAA-SH). Single-crystalline Au NPLs, synthesized using a one-step chemical vapor transport method, have ultraclean and ultraflat surfaces that make Cat-EAA-SH molecules aligned into a well-ordered network of a large-scale. Topographic study of the catechol-terminated molecules on Au NPLs using atomic force microscopy showed more orderly orientation and higher density, leading to significantly higher adhesion as observed from local force-distance curves than those on other Au surfaces. These coherently aligned catechol-terminated molecules on the atomically smooth gold surface led to significanty more reproducible and thus more physico-chemically meaningful measurements than was possible before by employing rough gold surfaces.

  18. Structure and kinetics of formation of catechol complexes of ferric soybean lipoxygenase-1

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, M.J.; Brennan, B.A.; Chase, D.B. [E.I. du Pont de Nemours & Co., Wilmington, DE (United States)]|[Haverford College, PA (United States)] [and others

    1995-11-21

    Ferric soybean lipoxygenase forms stable complexes with 4-substituted catechols. The structure of the complex between the enzyme and 3,4-dihydroxybenzonitrile has been studied by resonance Raman, electron paramagnetic resonance, visible, and X-ray spectroscopies. It is a bidentate iron-catecholate complex with at least one water ligand. The kinetics of formation of complexes between lipoxygenase and 3,4-dihydroxybenzonitrile and 3,4-dihydroxyacetophenone have been studied by stopped-flow spectroscopy. The data are consistent with two kinetically distinct, reversible steps. The pH dependence of the first step suggests that the substrate for the reaction is the catechol monoanion. When these results are combined, plausible mechanisms for the complexation reaction are suggested. 51 refs., 12 figs., 2 tabs.

  19. Copper-Aβ Peptides and Oxidation of Catecholic Substrates: Reactivity and Endogenous Peptide Damage.

    Science.gov (United States)

    Pirota, Valentina; Dell'Acqua, Simone; Monzani, Enrico; Nicolis, Stefania; Casella, Luigi

    2016-11-14

    The oxidative reactivity of copper complexes with Aβ peptides 1-16 and 1-28 (Aβ16 and Aβ28) against dopamine and related catechols under physiological conditions has been investigated in parallel with the competitive oxidative modification undergone by the peptides. It was found that both Aβ16 and Aβ28 markedly increase the oxidative reactivity of copper(II) towards the catechol compounds, up to a molar ratio of about 4:1 of peptide/copper(II). Copper redox cycling during the catalytic activity induces the competitive modification of the peptide at selected amino acid residues. The main modifications consist of oxidation of His13/14 to 2-oxohistidine and Phe19/20 to ortho-tyrosine, and the formation of a covalent His6-catechol adduct. Competition by the endogenous peptide is rather efficient, as approximately one peptide molecule is oxidized every 10 molecules of 4-methylcatechol.

  20. Multimodal underwater adsorption of oxide nanoparticles on catechol-based polymer nanosheets

    Science.gov (United States)

    Yamamoto, Shunsuke; Uchiyama, Shun; Miyashita, Tokuji; Mitsuishi, Masaya

    2016-03-01

    Multimodal underwater adsorption behaviour of catechol units was demonstrated by examining the adsorption of different oxide nanoparticles on nanoscale-integrated polymer nanosheets. Catechol-based polymer nanosheets were fabricated using the Langmuir-Blodgett (LB) technique with random copolymers (p(DDA/DMA)s) of N-dodecylacrylamide (DDA) and dopamine methacrylamide (DMA). The p(DDA/DMA) nanosheets were immersed into water dispersions of SiO2, Al2O3, and WO3 nanoparticles (NPs) respectively. The results show that the adsorption properties can be altered by varying the NP type: SiO2 NP adsorption was observed only below pH = 6, at which the o-quinone form in p(DDA/DMA) nanosheets transforms into the catechol form or vice versa. However, their transition point for Al2O3 NP adsorption was found at approximately pH 10, at which the surface potential of Al2O3 NPs changes the charge polarity, indicating that the electrostatic interaction is predominant. For WO3 NPs, adsorption was observed when citric acid, which modifies the surface of WO3 NPs by complex formation, was used as a pH-controlling agent, but no adsorption was found for hydrochloric acid used as a pH controlling agent. FT-IR measurements proved that miniscule amounts of water molecules were trapped in p(DDA/DMA) nanosheets and that they acquired hydrogen bonding network formations, which might assist nanoparticle adsorption underwater and make the catechol units adjustable. The results indicate that the nanoscale spatial arrangements of catechol units in films are crucially important for the application of multimodal adsorption of oxide nanoparticles on catechol-based polymer materials.Multimodal underwater adsorption behaviour of catechol units was demonstrated by examining the adsorption of different oxide nanoparticles on nanoscale-integrated polymer nanosheets. Catechol-based polymer nanosheets were fabricated using the Langmuir-Blodgett (LB) technique with random copolymers (p(DDA/DMA)s) of N

  1. Catechol versus bisphosphonate ligand exchange at the surface of iron oxide nanoparticles: towards multi-functionalization

    Science.gov (United States)

    Guénin, Erwann; Lalatonne, Yoann; Bolley, Julie; Milosevic, Irena; Platas-Iglesias, Carlos; Motte, Laurence

    2014-11-01

    We report an investigation of the ligand exchange at the surface of iron oxide nanoparticles in water. For this purpose we compared two strong chelating agents on the iron oxide surface containing catechol and bisphosphonate moieties. Interactions between the coating agents (catechol/bisphosphonate) and the nanoparticle's surface were studied by FTIR and DFT calculations. Ligand exchange experiments were performed using sonication and the exchange yield was characterized by FTIR and EDX. This methodology allowed introducing bisphosphonates with various functionalities (alkyne or biotin) permitting multi-functionalization.

  2. Intramolecular interactions in ortho-methoxyalkylphenylboronic acids and their catechol esters

    Science.gov (United States)

    Adamczyk-Woźniak, Agnieszka; Borys, Krzysztof M.; Czerwińska, Karolina; Gierczyk, Błażej; Jakubczyk, Michał; Madura, Izabela D.; Sporzyński, Andrzej; Tomecka, Ewelina

    2013-12-01

    Catechol esters of ortho-methoxyalkylphenylboronic acids have been synthesized and characterized by 17O NMR spectroscopy. The results were compared with the data for the parent acids. The influence of intramolecular and intermolecular hydrogen bonds on the properties of the boronic acids has been discussed. The 17O NMR data for the boronic esters proved that there are no O → B interactions in the investigated compounds. This fact is connected with weak Lewis acidity of the parent acids and their low sugars' receptors activity. Crystal structure of ortho-methoxyphenylboronic acid catechol ester was determined.

  3. Synthesis, molecular structure and magnetic properties of a rhenium(IV) compound with catechol

    Science.gov (United States)

    Cuevas, A.; Geis, L.; Pintos, V.; Chiozzone, R.; Sanchíz, J.; Hummert, M.; Schumann, H.; Kremer, C.

    2009-03-01

    A novel Re(IV) complex containing catechol as ligand has been prepared and characterized. The crystal structure of (HNEt 3)(NBu 4)[ReCl 4(cat)]·H 2cat was determined. The rhenium ion presents a distorted octahedral geometry, being bonded to a bidentate catecholate group and four chloride anions. The magnetic properties of the complex were studied, a /2 D/ (the energy gap between ±3/2 and ±1/2 Kramers doublets) value of 190(10) cm -1. This is the largest /2 D/ value reported for Re(IV) up to now.

  4. Plasma Activation of Integrated Carbon Nanotube Electrodes for Electrochemical Detection of Catechol

    Institute of Scientific and Technical Information of China (English)

    WANG Shenggao; WANG Tao; LI Yanqiong; ZHAO Xiujian; HAN Jianjun; WANG Jianhua

    2007-01-01

    In this study,integrated multi-wall carbon nanotube (MWCNT) electrodes were prepared in the holes of glass directly by microwave plasma chemical vapour deposition (MWPCVD).The electrochemical behaviour of catechol at the integrated MWCNT electrodes was investigated.The oxygen plasma treated CNT electrodes had better electrochemical performance for the analysis of catechol than that of as-synthesized CNT electrodes.Both the as-synthesized CNTs and plasma treated CNTs were characterized by TEM(transmission electron microscopy,XPS(X-ray photoelectron spectroscopy) and Raman spectroscopy.The results revealed that the oxygen plasma activation is an effective method to enhance the electrochemical properties of CNT electrodes.

  5. Correlation between Bonding Geometry and Band Gap States at Organic -- inorganic interfaces: Catechol on Rutile TiO2 (110)

    Science.gov (United States)

    Diebold, Ulrike; Li, Shao-Chun; Wang, Jian-Guo; Jacobson, Peter; Gong, Xue-Qing; Selloni, Annabella

    2009-03-01

    Adsorbate-induced band gap states in semiconductors are of particular interest due to the potential of increased light absorption and photoreactivity. A combined theoretical (DFT) and experimental (STM, photoemission) study of the molecular-scale factors involved in the formation of gap states in TiO2 is presented. Using the organic catechol on rutile TiO2(110) as a model system it is found that the bonding geometry strongly affects the molecular electronic structure. At saturation catechol forms an ordered 4 x 1 overlayer. This structure is attributed to catechol adsorbed on rows of surface Ti atoms with the molecular plane tilted from the surface normal by about ±27 in an alternating fashion. In the lowest-energy structure one of the two terminal OH groups at each catechol dissociates and the O binds to a surface Ti atom in a monodentate configuration, while the other OH group forms a H-bond to the next catechol neighbor. Through proton exchange with the surface this structure transforms into one where both OH groups dissociate and the catechol is bound to two surface Ti in a bidentate configuration. Only bidendate catechol introduces states in the band gap of TiO2.

  6. Cloning, expression, and characterization of catechol 1,2-dioxygenase from a phenol-degrading Candida tropicalis JH8 strain.

    Science.gov (United States)

    Long, Yan; Yang, Sheng; Xie, Zhixiong; Cheng, Li

    2016-10-02

    The sequence cato encoding catechol 1,2-dioxygenase from Candida tropicalis JH8 was cloned, sequenced, and expressed in Escherichia coli. The sequence cato contained an ORF of 858 bp encoding a polypeptide of 285 amino acid residues. The recombinant catechol 1,2-dioxygenase exists as a homodimer structure with a subunit molecular mass of 32 KD. Recombinant catechol 1,2-dioxygenase was unstable below pH 5.0 and stable from pH 7.0 to 9.0; its optimum pH was at 7.5. The optimum temperature for the enzyme was 30°C, and it possessed a thermophilic activity within a broad temperature range. Under the optimal conditions with catechol as substrate, the Km and Vmax of recombinant catechol 1,2-dioxygenase were 9.2 µM and 0.987 µM/min, respectively. This is the first article presenting cloning and expressing in E. coli of catechol 1,2-dioxygenase from C. tropicalis and characterization of the recombinant catechol 1,2-dioxygenase.

  7. Reaction Pathways in Catechol/Primary Amine Mixtures: A Window on Crosslinking Chemistry

    Science.gov (United States)

    Yang, Juan; Saggiomo, Vittorio; Velders, Aldrik H.; Cohen Stuart, Martien A.; Kamperman, Marleen

    2016-01-01

    Catechol chemistry is used as a crosslinking tool abundantly in both natural organisms (e.g. mussels, sandcastle worms) and synthetic systems to achieve the desired mechanical properties. Despite this abundance and success, the crosslinking chemistry is still poorly understood. In this study, to simplify the system, yet to capture the essential chemistry, model compounds 4-methyl catechol and propylamine are used. The reaction of 4-methyl catechol (2 mM) with propylamine (6 mM) is carried out in the presence of NaIO4 (2 mM) in 10 mM Na2CO3 aqueous solution. A variety of spectroscopic/spectrometric and chromatographic methods such as 1H NMR, LC-MS, and UV-VIS are used to track the reaction and identify the products/intermediates. It is found that the crosslinking chemistry of a catechol and an amine is both fast and complicated. Within five minutes, more than 60 products are formed. These products encompass 19 different masses ranging from molecular weight of 179 to 704. By combining time-dependent data, it is inferred that the dominant reaction pathways: the majority is formed via aryloxyl-phenol coupling and Michael-type addition, whereas a small fraction of products is formed via Schiff base reactions. PMID:27930671

  8. Oxidation of Catechol using Titanium Silicate (TS-1 Catalyst: Modeling and Optimization

    Directory of Open Access Journals (Sweden)

    Sonali Sengupta

    2013-12-01

    Full Text Available The oxidation of catechol was studied in an eco-friendly process with commercial titanium silicate-1 (TS-1 catalyst and hydrogen peroxide as oxidant in absence of all mass transfer effects. The process was opti-mized by Box-Behnken design in terms of three independent process variables such as reaction tempera-ture, moles of hydrogen peroxide per mole of catechol and catalyst amount whose optimum values of the process variables were found to be 60 °C, 13.2 and 1.24 g respectively for maximum conversion of 75.8 %. The effects of different process parameters such as mole ratio of hydrogen peroxide to catechol, catalyst par-ticle size, catalyst amount, temperature and reaction time were studied. A pseudo first order kinetic model was fitted with the experimental rate data. The apparent activation energy for the reaction was found to be 11.37 kJ/mole.  © 2013 BCREC UNDIP. All rights reservedReceived: 22nd April 2013; Revised: 25th October 2013; Accepted: 1st November 2013[How to Cite: Sengupta, S., Ghosal, D., Basu, J.K. (2013. Oxidation of Catechol using Titanium Silicate (TS-1 Catalyst: Modeling and Optimization. Bulletin of Chemical Reaction Engineering & Catalysis, 8 (2: 167-177. (doi:10.9767/bcrec.8.2.4759.167-177][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.8.2.4759.167-177

  9. Degradation of catechol by ionizing radiation, ozone and the combined process ozone-electron-beam

    Energy Technology Data Exchange (ETDEWEB)

    Kubesch, K. E-mail: sonja.solar@univie.ac.at; Zona, R.; Solar, S.; Gehringer, P

    2005-03-01

    The influence of oxygen on the radiation-induced degradation of catechol (5x10{sup -4} mol dm{sup -3}, 55 mg dm{sup -3}) in distilled water was studied by gamma-radiolysis in the presence of air (A) and using air saturation (AS) during irradiation. Under AS conditions a complete decomposition of catechol as well as of the trihydroxybenzene products was obtained by a dose of 6 kGy, without air saturation all phenolic compounds were still present at 10 kGy. Using AS, at 12 kGy the total organic carbon (TOC) was reduced by 63%, without air saturation by 17.5%. Detoxification was only obtained in AS solutions. In the presence of the natural matrix of the local tap water no trihydroxybenzene products were formed and for total decomposition of catechol in AS solutions 9 kGy were required. The comparison of the effectiveness of an electron beam (EB), an ozone (O{sub 3}) and a combined EB/O{sub 3} process showed, that by EB/O{sub 3} the extent of catechol degradation corresponded to the sum of the decay with EB and with ozone, whereas for the chemical oxygen demand and TOC reduction a synergistic effect was evident.

  10. Preserving the adhesion of catechol-conjugated hydrogels by thiourea-quinone coupling.

    Science.gov (United States)

    Xu, Yang J; Wei, Kongchang; Zhao, Pengchao; Feng, Qian; Choi, Chun Kit K; Bian, Liming

    2016-11-15

    Mussel adhesion has inspired the development of catechol-based adhesive polymers. However, conventional strategies require basic pH conditions and lead to the loss of adhesion. To solve the problem, we report the first attempt to use thiourea-functionalized polymers for preserving hydrogel adhesion. We believe that this simple thiourea-quinone coupling chemistry is instrumental to synthetic adhesive materials.

  11. Catechol-Bisphosphonate Conjugates:New Potential Chelating Agents for Metal Intoxication Therapy

    Institute of Scientific and Technical Information of China (English)

    Guang Yu XU; Chun Hao YANG; Bo LIU; Xi Han WU; Yu Yuan XIE

    2004-01-01

    In a quest for better chelating therapy drugs for the treatment of intoxication by Fe, Al, or actinides, two new series of mixed catechol-bisphosphonate through amide linkage were synthesized.Benzyl group was used as protecting group to avoid the breakage of amide by acid hydrolysis or imcomplete reaction in silylation-dealkylation using bromotrimethylsilane.

  12. Association of Catechol-O-Methyltransferase (COMT) Polymorphism and Academic Achievement in a Chinese Cohort

    Science.gov (United States)

    Yeh, Ting-Kuang; Chang, Chun-Yen; Hu, Chung-Yi; Yeh, Ting-Chi; Lin, Ming-Yeh

    2009-01-01

    Catechol-O-methyltransferase (COMT) is a methylation enzyme that catalyzes the degradation pathway and inactivation of dopamine. It is accepted widely as being involved in the modulation of dopaminergic physiology and prefrontal cortex (PFC) function. The COMT Val158Met polymorphism is associated with variation in COMT activity. COMT 158Met allele…

  13. Catechol-O-methyltransferase: a method for autoradiographic visualization of isozymes in cellogel

    Energy Technology Data Exchange (ETDEWEB)

    Brahe, C.; Crosti, N.; Meera Khan, P.; Serra, A.

    1984-02-01

    An electrophoretic procedure for separating the molecular forms of catechol-O-methyltransferase in cellulose acetate gel is described; the zones of enzyme activity were revealed by autoradiography. The electrophoretic patterns of the enzyme in several tissues and cell lines derived from four different species are presented.

  14. Revealing the role of catechol moieties in the interactions between peptides and inorganic surfaces.

    Science.gov (United States)

    Das, Priyadip; Reches, Meital

    2016-08-18

    Catechol (1,2-dihydroxy benzene) moieties are being widely used today in new adhesive technologies. Understanding their mechanism of action is therefore of high importance for developing their applications in materials science. This paper describes a single-molecule study of the interactions between catechol-related amino acid residues and a well-defined titanium dioxide (TiO2) surface. It is the first quantified measurement of the adhesion of these residues with a well-defined TiO2 surface. Single-molecule force spectroscopy measurements with AFM determined the role of different substitutions of the catechol moiety on the aromatic ring in the adhesion to the surface. These results shed light on the nature of interactions between these residues and inorganic metal oxide surfaces. This information is important for the design and fabrication of catechol-based materials such as hydrogels, coatings, and composites. Specifically, the interaction with TiO2 is important for the development of solar cells.

  15. Chloridazon-catechol dioxygenases, a distinct group of meta-cleaving enzymes.

    Science.gov (United States)

    Schmitt, S; Müller, R; Wegst, W; Lingens, F

    1984-02-01

    We previously described a new meta-cleaving enzyme, termed chloridazon-catechol dioxygenase. The present paper describes the comparison of this enzyme with the meta-cleaving enzymes of eighteen strains of soil bacteria isolated with various aromatic compounds. Four of these strains were isolated with the herbicide chloridazon, six with the analgeticum aminopyrine and one with the analgeticum antipyrine as sole carbon source. These strains all belonged to a new type of bacteria, called Phenylobacteria. The seven other strains were isolated with aromatic compounds such as toluene, 3-phenylpropionate, benzoate, papaverine and 4-chlorobenzoate, and belonged to various species including Pseudomonas, Acinetobacter and Nocardia. In double diffusion experiments with antibodies, prepared against chloridazon-catechol dioxygenase, extracts from the eleven strains of Phenylobacteria gave a cross reaction, whereas the extracts of the seven other strains showed no reaction. The enzymes of the eleven positive strains showed the same characteristic kinetic behaviour as the previously described enzyme. In contrast to catechol 2, 3-dioxygenase they needed the addition of exogenous Fe2+ ions for activity. On ion-exchange chromatography they emerged at the same buffer concentration as chloridazon-catechol dioxygenase. In polyacrylamide electrophoresis they migrated identically. The linkage map derived from the activities of the various enzymes with 10 different substrates revealed an identity of more than 80% for these eleven enzymes. So the meta-cleaving enzymes of the Phenylobacteria seem to form a distinct group among the non-heme iron-containing dioxygenases.

  16. Chromium(VI) reduction by catechol(amine)s results in DNA cleavage in vitro

    DEFF Research Database (Denmark)

    Pattison, D I; Davies, Michael Jonathan; Levina, A;

    2001-01-01

    ) or 4-tert-butylcatechol (5) do not damage DNA. The Cr(VI)/catechol(amine) reactions have been studied at low added H(2)O(2) concentrations, which lead to enhanced DNA cleavage with 1 and induce DNA cleavage with 4. The Cr(V) and organic intermediates generated by the reactions of Cr(VI) with 1 or 4...

  17. Synthesis, characterization and self-assembly of Co3+ complexes appended with phenol and catechol groups

    Indian Academy of Sciences (India)

    Afsar Ali; Deepak Bansal; Rajeev Gupt

    2014-09-01

    This work presents the syntheses, characterization and hydrogen bonding based self-assembly of Co3+ complexes of pyridine-amide based bidentate ligands containing appended phenol and catechol groups. Placement of multiple hydrogen bond donors (phenolic OH and amidic NH groups) and acceptors (Oamide groups) in these molecules results in interesting self-assembled architectures.

  18. Catechol-O-methyltransferase gene methylation and substance use in adolescents : the TRAILS study

    NARCIS (Netherlands)

    van der Knaap, L. J.; Schaefer, J. M.; Franken, I. H. A.; Verhulst, F. C.; van Oort, F. V. A.; Riese, H.

    2014-01-01

    Substance use often starts in adolescence and poses a major problem for society and individual health. The dopamine system plays a role in substance use, and catechol-O-methyltransferase (COMT) is an important enzyme that degrades dopamine. The Val(108/158)Met polymorphism modulates COMT activity an

  19. Organic impurity profiling of 3,4-methylenedioxymethamphetamine (MDMA) synthesised from catechol.

    Science.gov (United States)

    Heather, Erin; Shimmon, Ronald; McDonagh, Andrew M

    2015-03-01

    This work examines the organic impurity profile of 3,4-methylenedioxymethamphetamine (MDMA) that has been synthesised from catechol (1,2-dihydroxybenzene), a common chemical reagent available in industrial quantities. The synthesis of MDMA from catechol proceeded via the common MDMA precursor safrole. Methylenation of catechol yielded 1,3-benzodioxole, which was brominated and then reacted with magnesium allyl bromide to form safrole. Eight organic impurities were identified in the synthetic safrole. Safrole was then converted to 3,4-methylenedioxyphenyl-2-propanone (MDP2P) using two synthetic methods: Wacker oxidation (Route 1) and an isomerisation/peracid oxidation/acid dehydration method (Route 2). MDMA was then synthesised by reductive amination of MDP2P. Thirteen organic impurities were identified in MDMA synthesised via Route 1 and eleven organic impurities were identified in MDMA synthesised via Route 2. Overall, organic impurities in MDMA prepared from catechol indicated that synthetic safrole was used in the synthesis. The impurities also indicated which of the two synthetic routes was utilised.

  20. Xylem occlusion in Bouvardia flowers : evidence for a role of peroxidase and catechol oxidase

    NARCIS (Netherlands)

    Vaslier, N.; Doorn, van W.G.

    2003-01-01

    During vase life, Bouvardia flowers show rapid leaf wilting, especially if they are stored dry prior to placement in water. Wilting is due to a blockage in the basal stem end. We investigated the possible role of peroxidase and catechol oxidase in the blockage in cv. van Zijverden flowers, which wer

  1. Free radical scavenging potency of quercetin catecholic colonic metabolites: Thermodynamics of 2H(+)/2e(-) processes.

    Science.gov (United States)

    Amić, Ana; Lučić, Bono; Stepanić, Višnja; Marković, Zoran; Marković, Svetlana; Dimitrić Marković, Jasmina M; Amić, Dragan

    2017-03-01

    Reaction energetics of the double (2H(+)/2e(-)), i.e., the first 1H(+)/1e(-) (catechol→ phenoxyl radical) and the second 1H(+)/1e(-) (phenoxyl radical→ quinone) free radical scavenging mechanisms of quercetin and its six colonic catecholic metabolites (caffeic acid, hydrocaffeic acid, homoprotocatechuic acid, protocatechuic acid, 4-methylcatechol, and catechol) were computationally studied using density functional theory, with the aim to estimate the antiradical potency of these molecules. We found that second hydrogen atom transfer (HAT) and second sequential proton loss electron transfer (SPLET) mechanisms are less energy demanding than the first ones indicating 2H(+)/2e(-) processes as inherent to catechol moiety. The Gibbs free energy change for reactions of inactivation of selected free radicals indicate that catecholic colonic metabolites constitute an efficient group of more potent scavengers than quercetin itself, able to deactivate various free radicals, under different biological conditions. They could be responsible for the health benefits associated with regular intake of flavonoid-rich diet.

  2. Iron(III) complexes of certain tetradentate phenolate ligands as functional models for catechol dioxygenases

    Indian Academy of Sciences (India)

    Mallayan Palaniandavar; Marappan Velusamy; Ramasamy Mayilmurugan

    2006-11-01

    Catechol 1,2-dioxygenase (CTD) and protocatechuate 3,4-dioxygenase (PCD) are bacterial non-heme iron enzymes, which catalyse the oxidative cleavage of catechols to cis, cis-muconic acids with the incorporation of molecular oxygen via a mechanism involving a high-spin ferric centre. The iron(III) complexes of tripodal phenolate ligands containing N3O and N2O2 donor sets represent the metal binding region of the iron proteins. In our laboratory iron(III) complexes of mono- and bisphenolate ligands have been studied successfully as structural and functional models for the intradiol-cleaving catechol dioxygenase enzymes. The single crystal X-ray crystal structures of four of the complexes have been determined. One of the bis-phenolato complexes contains a FeN2O2Cl chromophore with a novel trigonal bipyramidal coordination geometry. The Fe-O-C bond angle of 136.1° observed for one of the iron(III) complex of a monophenolate ligand is very similar to that in the enzymes. The importance of the nearby sterically demanding coordinated -NMe2 group has been established and implies similar stereochemical constraints from the other ligated amino acid moieties in the 3,4-PCD enzymes, the enzyme activity of which is traced to the difference in the equatorial and axial Fe-O(tyrosinate) bonds (Fe-O-C, 133, 148°). The nature of heterocyclic rings of the ligands and the methyl substituents on them regulate the electronic spectral features, FeIII/FeII redox potentials and catechol cleavage activity of the complexes. Upon interacting with catecholate anions, two catecholate to iron(III) charge transfer bands appear and the low energy band is similar to that of catechol dioxygenase-substrate complex. Four of the complexes catalyze the oxidative cleavage of H2DBC by molecular oxygen to yield intradiol cleavage products. Remarkably, the more basic N-methylimidazole ring in one of the complexes facilitates the rate-determining productreleasing phase of the catalytic reaction. The present

  3. Adsorption Properties of Ionic Species on Cross-linked Chitosans Modified with Catechol and Salicylic Acid Moieties

    OpenAIRE

    Oshita, Koji; Takayanagi, Toshio; Oshima, Mitsuko; Motomizu, Shoji

    2008-01-01

    Catechol-type chitosan resin and salicylic acid-type chitosan resin were easily synthesized for use in estimating the adsorption behavior of 34 elements at pH 1 - 7 in aquatic media. The catechol-type chitosan resin could adsorb Cu(II) at pH 3 - 7, In(III) at pH 4 - 6, Pb(II) and lanthanoids at pH 5 - 7, and U(VI) at pH 4 - 7 more effectively than the salicylic acid-type chitosan resin and the cross-linked chitosan resin (base material). Adsorption ability was in the order: catechol-type chit...

  4. The role of the interaction between oxygen and catechol in the pitting corrosion of steel in alkaline sulfide solutions

    Energy Technology Data Exchange (ETDEWEB)

    Kannan, S.; Kelly, R.G. [Univ. of Virginia, Charlottesville, VA (United States)

    1995-12-01

    Black liquor corrosivity is shown to depend on the interaction of the chemical species present. Specifically, an interaction between oxygen and 1,2-dihydroxybenzene compounds (catechols) in alkaline sulfide solutions leads to a distinct increase in the severity of the attack. This increased corrosivity is explained in terms of the oxidation of catechol leading to increased open circuit potentials for steel. The importance of the ratio of sulfide concentration to hydroxyl concentration in the initiation of pitting is stressed. The possible role of catechol in stabilizing metastable pits is also discussed.

  5. Reactivity and selectivity differences between catecholate and catechothiolate Ru complexes. Implications regarding design of stereoselective olefin metathesis catalysts.

    Science.gov (United States)

    Khan, R Kashif M; Torker, Sebastian; Hoveyda, Amir H

    2014-10-15

    The origins of the unexpected finding that Ru catechothiolate complexes, in contrast to catecholate derivatives, promote exceptional Z-selective olefin metathesis reactions are elucidated. We show that species containing a catechothiolate ligand, unlike catecholates, preserve their structural integrity under commonly used reaction conditions. DFT calculations indicate that, whereas alkene coordination is the stereochemistry-determining step with catecholate complexes, it is through the metallacyclobutane formation that the identity of the major isomer is determined with catechothiolate systems. The present findings suggest that previous models for Z selectivity, largely based on steric differences, should be altered to incorporate electronic factors as well.

  6. Growth of Actinobacillus pleuropneumoniae is promoted by exogenous hydroxamate and catechol siderophores.

    Science.gov (United States)

    Diarra, M S; Dolence, J A; Dolence, E K; Darwish, I; Miller, M J; Malouin, F; Jacques, M

    1996-03-01

    Siderophores bind ferric ions and are involved in receptor-specific iron transport into bacteria. Six types of siderophores were tested against strains representing the 12 different serotypes of Actinobacillus pleuropneumoniae. Ferrichrome and bis-catechol-based siderophores showed strong growth-promoting activities for A. pleuropneumoniae in a disk diffusion assay. Most strains of A. pleuropneumoniae tested were able to use ferrichrome (21 of 22 or 95%), ferrichrome A (20 of 22 or 90%), and lysine-based bis-catechol (20 of 22 or 90%), while growth of 36% (8 of 22) was promoted by a synthetic hydroxamate, N5-acetyl-N5-hydroxy-L-ornithine tripeptide. A. pleuropneumoniae serotype 1 (strain FMV 87-682) and serotype 5 (strain 2245) exhibited a distinct yellow halo around colonies on Chrome Azurol S agar plates, suggesting that both strains can produce an iron chelator (siderophore) in response to iron stress. The siderophore was found to be neither a phenolate nor a hydroxamate by the chemical tests of Arnow and Csaky, respectively. This is the first report demonstrating the production of an iron chelator and the use of exogenous siderophores by A. pleuropneumoniae. A spermidine-based bis-catechol siderophore conjugated to a carbacephalosporin was shown to inhibit growth of A. pleuropneumoniae. A siderophore-antibiotic-resistant strain was isolated and shown to have lost the ability to use ferrichrome, synthetic hydroxamate, or catechol-based siderophores when grown under conditions of iron restriction. This observation indicated that a common iron uptake pathway, or a common intermediate, for hydroxamate- and catechol-based siderophores may exist in A. pleuropneumoniae.

  7. Application of an easily water-compatible hypercrosslinked polymeric adsorbent for efficient removal of catechol and resorcinol in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Huang Jianhan, E-mail: xiaomeijiangou@yahoo.com.cn [College of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China); Huang Kelong; Yan Cheng [College of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China)

    2009-08-15

    An easily water-compatible hypercrosslinked resin HJ-1 was developed for adsorbing catechol and resorcinol in aqueous solution in this study. Its adsorption performances for catechol and resorcinol were investigated in aqueous solution by using the commercial Amberlite XAD-4 as a reference. The adsorption dynamic curves were measured and the adsorption obeyed the pseudo-second-order rate equation of Boyer and Hsu. The adsorption isotherms were scaled and Freundlich isotherm model characterized the adsorption better. The adsorption thermodynamic parameters were calculated and the adsorption was an exothermic, favorable, and more ordered process. The fact that the adsorption capacity of catechol was larger than resorcinol and the adsorption enthalpy of catechol was more negative than resorcinol can be explained in terms of the solubility and the polarity of two adsorbates.

  8. Regulation of aromatics biodegradation by rhl quorum sensing system through induction of catechol meta-cleavage pathway.

    Science.gov (United States)

    Yong, Yang-Chun; Zhong, Jian-Jiang

    2013-05-01

    The mechanism for quorum sensing (QS) regulation on aromatics degradation was investigated. Deletion of rhl QS system resulted in a significant decrease in aromatics biodegradation as well as the activity of catechol 2,3-dioxygenase (C23O, key enzyme for catechol meta-cleavage pathway) in Pseudomonas aeruginosa CGMCC1.860. Interestingly, this repression could be relieved by N-butyryl homoserine lactone (the signaling molecule of rhl QS system) addition. In accordance, the transcription level of nahH (the gene encoding C23O) and nahR (transcriptional activator) also responded to rhl perturbation in a similar way. The results indicated that rhl QS system positively controlled the catechol meta-cleavage pathway, and hence improved aromatics biodegradation. It suggested manipulation of QS system could be a promising strategy to tune the catechol cleavage pathway and to control aromatics biodegradation.

  9. C{sub 24}H{sub 14} polycyclic aromatic hydrocarbons from the pyrolysis of catechol

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, S.; Wornat, M.J. [Louisiana State University, Baton Rouge, LA (United States). Dept. of Chemical Engineering

    2008-07-01

    Polycyclic aromatic hydrocarbons (PAH) of the C{sub 24}H{sub 14} isomer class, some of which are potent mutagens and carcinogens, are produced during the burning of solid fuels. For a clearer understanding of the formation of PAH, pyrolysis experiments have been performed in an isothermal laminar-flow reactor with the model fuel catechol (ortho-dihydroxybenzene) - a phenol-type compound representative of structural entities in complex solid fuels like coal, wood, and biomass. The catechol pyrolysis experiments are conducted at 1000{sup o}C and at a residence time of 0.3 s. The pyrolysis products are analysed by high-pressure liquid chromatography with ultraviolet-visible absorbance detection and mass spectrometric detection. Product analysis reveals that the C{sub 24}H{sub 14} PAH products of catechol pyrolysis belong to three structural classes: perylene benzologues, fluoranthene benzologues and pyrene benzologues. The 12 C{sub 24}H{sub 14} PAH identified in the present study are: benzo(b)perylene, naphtho(1,2-b)fluoranthene, naphtho(1,2-k)fluoranthene, dibenzo(b,k)fluoranthene, naphtho(2,3-b)fluoranthene, naphtho(2,3-k)fluoranthene, naphtho(1,2-e)pyrene, naphtho(2,3-e)pyrene, naphtho(1,2-a)pyrene, dibenzo(a,e)pyrene, dibenzo(e, l)pyrene, and dibenzo(a,h)pyrene. In addition to these, our earlier identifications of naphtho(2,1-a)pyrene, naphtho(2,3-a)pyrene, and dibenzo(a,i)pyrene among the products of catechol pyrolysis bring the total number of C{sub 24}H{sub 14} PAH identified as products of catechol pyrolysis to 15. Of these 15, 12 have been reported to be mutagens and 6 have been reported to be carcinogens. The UV spectra establishing the identities of the 15 C{sub 24}H{sub 14} catechol pyrolysis products are presented.

  10. pH-dependent cross-linking of catechols through oxidation via Fe(3+) and potential implications for mussel adhesion.

    Science.gov (United States)

    Fullenkamp, Dominic E; Barrett, Devin G; Miller, Dusty R; Kurutz, Josh W; Messersmith, Phillip B

    2014-01-01

    The mussel byssus is a remarkable attachment structure that is formed by injection molding and rapid in-situ hardening of concentrated solutions of proteins enriched in the catecholic amino acid 3,4-dihydroxy-L-phenylalanine (DOPA). Fe(3+), found in high concentrations in the byssus, has been speculated to participate in redox reactions with DOPA that lead to protein polymerization, however direct evidence to support this hypothesis has been lacking. Using small molecule catechols, DOPA-containing peptides, and native mussel foot proteins, we report the first direct observation of catechol oxidation and polymerization accompanied by reduction of Fe(3+) to Fe(2+). In the case of the small molecule catechol, we identified two dominant dimer species and characterized their connectivities by nuclear magnetic resonance (NMR), with the C6-C6 and C5-C6 linked species as the major and minor products, respectively. For the DOPA-containing peptide, we studied the pH dependence of the reaction and demonstrated that catechol polymerization occurs readily at low pH, but is increasingly diminished in favor of metal-catechol coordination interactions at higher pH. Finally, we demonstrate that Fe(3+) can induce cross-links in native byssal mussel proteins mefp-1 and mcfp-1 at acidic pH. Based on these findings, we discuss the potential implications to the chemistry of mussel adhesion.

  11. Evolution of CO{sub 2} during birnessite-induced oxidation of {sup 14}C-labeled catechol

    Energy Technology Data Exchange (ETDEWEB)

    Majcher, E.H.; Chorover, J.; Bollag, J.M.; Huang, P.M.

    2000-02-01

    Phenolic compounds undergo several transformation processes in soil and water (i.e., partial degradation, mineralization, and polymerization), many of which have been attributed primarily to biological activity. Results from previous work indicate that naturally occurring Mn oxides are also capable of oxidizing phenolic compounds. In the present study, {sup 14}C-labeled catechol was reacted with birnessite (manganese oxide) in aqueous suspension of pH 4. The mass of catechol-derived c in solid, solution, and gas phases was quantified as a function of time. Between 5 and 16% of the total catechol C was liberated as CO{sub 2} from oxidation and abiotic ring cleavage under various conditions. Most of the {sup 14}C (55--83%) was incorporated into the solid phase in the form of stable organic reaction products whereas solution phase {sup 14}C concentrations increased from 16 to 39% with a doubling of total catechol added. Polymerization and CO{sub 2} evolution appear to be competitive pathways in the transformation of catechol since their relative importance was strongly dependent on initial birnessite-catechol reaction conditions. Solid phase Fourier transform infrared (FTIR) spectra are consistent with the presence of phenolic, quinone, and aromatic ring cleavage products. Carbon dioxide release appears to be limited by availability of reactive birnessite surface sites and it is diminished in the presence of polymerized reaction products.

  12. Development of catechol 2,3-dioxygenase-specific primers for monitoring bioremediation by competitive quantitative PCR

    Energy Technology Data Exchange (ETDEWEB)

    Mesarch, M.B.; Nakatsu, C.H.; Nies, L.

    2000-02-01

    Benzene, toluene, xylenes, phenol, naphthalene, and biphenyl are among a group of compounds that have at least one reported pathway for biodegradation involving catechol 2,3-dioxygenase enzymes. Thus, detection of the corresponding catechol 2,3-dioxygenase genes can serve as a basis for identifying and quantifying bacteria that have these catabolic abilities. Primes that can successfully amplify a 238-bp catechol 2,3-dioxygenase gene fragment from eight different bacteria are described. The identities of the amplicons were confirmed by hybridization with a 238-bp catechol 2,3-dioxygenase probe. The detection limit was 10{sup 2} to 10{sup 3} gene copies, which was lowered to 10{sup 0} to 10{sup 1} gene copies of hybridization. Using the dioxygenase-specific primers, an increase in catechol 2,3-dioxygenase genes was detected in petroleum-amended soils. The dioxygenase genes were enumerated by competitive quantitative PCR and a 163-bp competitor that was amplified using the same primers. Target and competitor sequences had identical amplification kinetics. Potential PCR inhibitors that could coextract with DNA, nonamplifying DNA, soil factors (humics), and soil pollutants (toluene) did not impact enumeration. Therefore, this technique can be used to accurately and reproducibly quantify catechol 2,3-dioxygenase genes in complex environments such as petroleum-contaminated soil. Direct, non-cultivation-based molecular techniques for detecting and enumerating microbial pollutant-biodegrading genes in environmental samples are powerful tools for monitoring bioremediation and developing field evidence in support of natural attenuation.

  13. Clean and Green Synthesis of New Benzothiazole Derivatives via Electrochemical Oxidation of Catechol Derivatives

    Directory of Open Access Journals (Sweden)

    Mansour Arab Chamjangali

    2016-06-01

    Full Text Available Electrochemical oxidation of the catechols 1a and 1b is studied in the presence of 6-methyl-2-thouracil (3b and 6-propyl-2-thiouracil (3a as nucleophiles in a phosphate buffer (0.15 mol L−1, pH = 6.8/DMF (95:5 solution using cyclic voltammetry and controlled-potential coulometry. The results obtained indicate that the quinones derived from the catechols participate in 1,4-Michael-addition reactions with the nucleophiles to form the corresponding new benzothiazole compounds. In this work, we derive a variety of products with good yields using controlled potential at graphite electrodes in an undivided cell. This work is licensed under a Creative Commons Attribution 4.0 International License.

  14. Catechol Removal from Aqueous Media Using Laccase Immobilized in Different Macro- and Microreactor Systems.

    Science.gov (United States)

    Tušek, Ana Jurinjak; Šalić, Anita; Zelić, Bruno

    2017-01-23

    Laccase belongs to the group of enzymes that are capable to catalyze the oxidation of phenols. Since the water is only by-product in laccase-catalyzed phenol oxidations, it is ideally "green" enzyme with many possible applications in different industrial processes. To make the oxidation process more sustainable in terms of biocatalyst consumption, immobilization of the enzyme is implemented in to the processes. Additionally, when developing a process, choice of a reactor type plays a significant role in the total outcome.In this study, the use of immobilized laccase from Trametes versicolor for biocatalytic catechol oxidation was explored. Two different methods of immobilization were performed and compared using five different reactor types. In order to compare different systems used for catechol oxidation, biocatalyst turnover number and turnover frequency were calculated. With low consumption of the enzyme and good efficiency, obtained results go in favor of microreactors with enzyme covalently immobilized on the microchannel surface.

  15. Characterization of catechol 1,2-dioxygenase from cell extracts of Sphingomonas xenophaga QYY

    Institute of Scientific and Technical Information of China (English)

    GOU Min; QU YuanYuan; ZHOU JiTi; LI Ang; M.Salah Uddin

    2009-01-01

    Sphingomonas xenophaga QYY, capable of growing significantly on more than ten kinds of aromatic compounds as sole carbon source, was used to study characterization of catechol 1,2-dioxygenase (C120) in cell extracts. Characterization of the crude C120 showed that the maximum activity was obtained at 40-70℃ and pH 7.8-8.8. Metal ions had different influences on the activity of crude C120. It was suggested that strain QYY possessed an inducible and ferric-dependent C120. Kinetic studies showed that the value of Vmax and Km was 0.25 μmol catechol/L/mg protein/min and 52.85 μmol/L, respectively. In addition, the partial purification of C120 was achieved by a HiTrap Q Sepharose column chromatography.

  16. Crystallization and preliminary X-ray diffraction studies of a catechol-O-methyltransferase/inhibitor complex

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, M. L. [Instituto de Tecnologia Química e Biológica (ITQB), Universidade Nova de Lisboa, Av. República, Apt. 127, 2781-901 Oeiras (Portugal); Bonifácio, M. J.; Soares-da-Silva, P. [Department of Research and Development, BIAL, 4785 S. Mamede do Coronado (Portugal); Carrondo, M. A.; Archer, M., E-mail: archer@itqb.unl.pt [Instituto de Tecnologia Química e Biológica (ITQB), Universidade Nova de Lisboa, Av. República, Apt. 127, 2781-901 Oeiras (Portugal)

    2005-01-01

    Catechol-O-methyltransferase has been co-crystallized with a novel inhibitor, which has potential therapeutic application in the Parkinson’s disease therapy. Inhibitors of the enzyme catechol-O-methyltransferase (COMT) are used as co-adjuvants in the therapy of Parkinson’s disease. A recombinant form of the soluble cytosolic COMT from rat has been co-crystallized with a new potent inhibitor, BIA 8-176 [(3,4-dihydroxy-2-nitrophenyl)phenylmethanone], by the vapour-diffusion method using PEG 6K as precipitant. Crystals diffract to 1.6 Å resolution on a synchrotron-radiation source and belong to the monoclinic space group P2{sub 1}, with unit-cell parameters a = 52.77, b = 79.63, c = 61.54 Å, β = 91.14°.

  17. Characterization of catechol 1,2-dioxygenase from cell extracts of Sphingomonas xenophaga QYY

    Institute of Scientific and Technical Information of China (English)

    M.Salah; Uddin

    2009-01-01

    Sphingomonas xenophaga QYY, capable of growing significantly on more than ten kinds of aromatic compounds as sole carbon source, was used to study characterization of catechol 1,2-dioxygenase (C12O) in cell extracts. Characterization of the crude C12O showed that the maximum activity was obtained at 40-70℃ and pH 7.8-8.8. Metal ions had different influences on the activity of crude C12O. It was suggested that strain QYY possessed an inducible and ferric-dependent C12O. Kinetic studies showed that the value of Vmax and Km was 0.25 μmol catechol/L/mg protein/min and 52.85 μmol/L, respectively. In addition, the partial purification of C12O was achieved by a HiTrap Q Sepharose column chromatography.

  18. Polymeric Framboidal Nanoparticles Loaded with a Carbon Monoxide Donor via Phenylboronic Acid-Catechol Complexation.

    Science.gov (United States)

    van der Vlies, André J; Inubushi, Ryosuke; Uyama, Hiroshi; Hasegawa, Urara

    2016-06-15

    Carbon monoxide (CO) is an essential gaseous signaling molecule in the human body. Toward the controlled delivery of CO to the target tissues or cells, nanomaterial-based CO donors have attracted growing attention. Here, we present CO-releasing polymeric nanoparticles (CONPs) prepared by simple mixing of phenylboronic acid-containing framboidal nanoparticles with the catechol-bearing CO-donor Ru(CO)3Cl(L-DOPA) via phenylboronic acid-catechol complexation. The CONPs release CO in response to cysteine and suppress the production of the pro-inflammatory mediators interleukin 6 (IL-6) and nitric oxide (NO) in lipopolysaccharide (LPS)-stimulated murine macrophages. This CONP platform may show promise in therapeutic applications of CO.

  19. Crystal structure of thermostable catechol 2,3-dioxygenase determined by multiwavelength anomalous dispersion method

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The selenomethionyl derivative of the thermostable catechol 2,3-dioxygenase (SeMet-TC23O) is expressed,purified and crystallized. By using multiwave length anomalous dispersion (MAD) phasing techniques, the crystal structure of TC23O at 0.3 nm resolutions is determined.TC23O is a homotetramer. Each monomer is composed of N-terminal and C-terminal domains (residues 1~153 and 153~319, respectively). The two domains are proximately symmetric by a non-crystallographic axis. Each domain contains two characteristic motifs which are found in almost all of extradial dioxygenases.Kevwords: multiwavelength anomalous dispersion (MAD), X-ray diffraction, thermostable catechol 2,3-dioxygenase, crystal structure,synchrotron light source.

  20. Robust Alginate-Catechol@Polydopamine Free-Standing Membranes Obtained from the Water/Air Interface.

    Science.gov (United States)

    Ponzio, Florian; Le Houerou, Vincent; Zafeiratos, Spyridon; Gauthier, Christian; Garnier, Tony; Jierry, Loic; Ball, Vincent

    2017-03-07

    The formation of polydopamine composite membranes at the water/air interface using different chemical strategies is reported. The use of either small molecules (urea, pyrocatechol) or polymers paves the way to understand which kind of compounds can be used for the formation of PDA-composite free-standing membranes produced at the water/air interface. On the basis of these screening results, we have found that alginate grafted with catechol groups allows the formation of robust free-standing films with asymmetric composition, stimuli-responsiveness, and self-healing properties. The stickiness of these membranes depends on the relative humidity, and its adhesion behavior on PDMS was characterized using the JKR method. Thus, alginate-catechol polydopamine films appear as a new class of PDA composites, mechanically robust through covalent cross-linking and based on fully biocompatible constituting partners. These results open the door to potential applications in the biomedical field.

  1. New Hybrid Properties of TiO2 Nanoparticles Surface Modified With Catecholate Type Ligands

    Science.gov (United States)

    Janković, Ivana A.; Šaponjić, Zoran V.; Džunuzović, Enis S.; Nedeljković, Jovan M.

    2010-01-01

    Surface modification of nanocrystalline TiO2 particles (45 Å) with bidentate benzene derivatives (catechol, pyrogallol, and gallic acid) was found to alter optical properties of nanoparticles. The formation of the inner-sphere charge-transfer complexes results in a red shift of the semiconductor absorption compared to unmodified nanocrystallites. The binding structures were investigated by using FTIR spectroscopy. The investigated ligands have the optimal geometry for chelating surface Ti atoms, resulting in ring coordination complexes (catecholate type of binuclear bidentate binding-bridging) thus restoring in six-coordinated octahedral geometry of surface Ti atoms. From the Benesi-Hildebrand plot, the stability constants at pH 2 of the order 103 M-1 have been determined.

  2. Carrier-microencapsulation using Si-catechol complex for suppressing pyrite floatability

    Energy Technology Data Exchange (ETDEWEB)

    Jha, R.K.T.; Satur, J.; Hiroyoshi, N.; Ito, M.; Tsunekawa, M. [Hokkaido University, Hokkaido (Japan). Graduate School of Engineering

    2008-11-15

    Pyrite (FeS{sub 2}) is a common sulfide mineral associated with valuable metal minerals and coal, and it is rejected as a gangue mineral using physical separation techniques such as froth flotation and discharged into tailing pond. In the flotation, pyrite is frequently entrapped in the froth due to its hydrophobic nature. Formation of acid mine drainage due to the air-oxidation of pyrite in the tailing pond is also a serious problem. The authors have proposed carrier-microencapsulation (CME) as a method for suppressing both the floatability and oxidation of pyrite. In this method, pyrite is coated with a thin layer of metal oxide or hydroxide using catechol solution as a carrier combined with metal ions. The layer converts the pyrite surface from hydrophobic to hydrophilic and acts as a protective coating against oxidation. The present study demonstrates the effect of CME using Si-catechol complex to suppress the pyrite floatability: The bubble pick-up experiments showed that attachment of pyrite particles to air bubble is suppressed by the CME treatment at pH 4-10, Si-catechol complex concentration over 0.5 mol m{sup -3} and treatment time within 2 min. The Hallimond tube flotation experiments showed that the pyrite floatability is suppressed by the CME treatment even in the presence of typical flotation collectors such as kerosene and xanthate. SEM-EDX analysis confirmed that Si present on the pyrite surface treated by Si-catechol complex, implying that SiO{sub 2} or SiOH{sub 4} layer formed by the CME treatment convert the pyrite surface hydrophobic to hydrophilic.

  3. Lubricating oil compositions containing overbased calcium sulfonates and metal salts of alkyl catechol dithiophosphoric acid

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, E.S.; Cerrito, E.; Liston, T.V.

    1987-05-26

    This patent describes a lubricating oil composition containing an overbased calcium hydrocarbyl sulfonate. The improvement wherein the lubricating oil composition additionally comprises an effective amount to reduce wear of a metal salt of an alkyl catechol dithiophosphoric acid ester of the formula: wherein R is alkyl containing 10 to 18 carbon atoms, or mixtures thereof, M is an alkali or alkaline earth metal or transition metal and n corresponds to the valence of the metal M.

  4. Synthesis of 4-O-Methylcedrusin. Selective Protection of Catechols with Diphenyl Carbonate

    Directory of Open Access Journals (Sweden)

    Roger Dommisse

    2000-02-01

    Full Text Available 4-O-Methylcedrusin, a minor component in ‘sangre de drago’, has been synthesized using a strategy of successive protection and deprotection reactions under very mild conditions. The key step of this synthesis is a selective protection of a catechol group as a cyclic carbonate in the presence of an isolated phenol group.

  5. Growth of Actinobacillus pleuropneumoniae is promoted by exogenous hydroxamate and catechol siderophores.

    OpenAIRE

    Diarra, M. S.; Dolence, J A; Dolence, E K; Darwish, I; Miller, M.J.; Malouin, F; Jacques, M.

    1996-01-01

    Siderophores bind ferric ions and are involved in receptor-specific iron transport into bacteria. Six types of siderophores were tested against strains representing the 12 different serotypes of Actinobacillus pleuropneumoniae. Ferrichrome and bis-catechol-based siderophores showed strong growth-promoting activities for A. pleuropneumoniae in a disk diffusion assay. Most strains of A. pleuropneumoniae tested were able to use ferrichrome (21 of 22 or 95%), ferrichrome A (20 of 22 or 90%), and ...

  6. Synthesis of 4-O-Methylcedrusin. Selective Protection of Catechols with Diphenyl Carbonate

    OpenAIRE

    Roger Dommisse; Jonckers, Tim H M; Guy L. F. Lemière; Dyck, Stefaan M. O. Van

    2000-01-01

    4-O-Methylcedrusin, a minor component in ‘sangre de drago’, has been synthesized using a strategy of successive protection and deprotection reactions under very mild conditions. The key step of this synthesis is a selective protection of a catechol group as a cyclic carbonate in the presence of an isolated phenol group.

  7. The Role of Catechol-O-Methyltransferase (COMT Gene in the Etiopathogenesis of Schizophrenia

    Directory of Open Access Journals (Sweden)

    Ceren Acar

    2014-09-01

    Full Text Available Genetic factors in the risk of developing schizophrenia is of great importance. With the help of the advances in the field of genetics in recent years by using linkage analysis several genes have been identified that may be a risk factor in schizophrenia. Several association studies have been performed in many different populations on the candidate susceptibility genes that were defined in previous studies. However, these studies give controversial results in different countries with different populations, and there are problems in obtaining replicable results. In this review we aimed to focus on the genetic basis of schizophrenia and the relationship between schizophrenia and catechol-O-methyltransferase (COMT gene. COMT encodes an enzyme molecule which has an important function in dopamine pathways. It has great importance in catecholamine metabolism and pharmacology and genetic mechanism of catechol metabolism variations and their clinical consequences. COMT transfers the methyl group from S-adenosyl-methionine to the hydroxyl group of catechol nucleus (such as dopamine, norepinephrine or catechol estrogen. Genetic variations found in COMT gene are associated with a broad spectrum of clinical phenotype including psychiatric disorders or estrogen related cancers. Several groups have performed studies on the relationship between schizophrenia and COMT. The most commonly studied polymorphism in COMT gene is rs4680 and it causes a valine methionine conversion at codon 158. The association studies on this polymorphism in different populations gave both positive and negative results. Schizoprenia is a complex disease caused by the interaction of environmental and genetic factors, while interpreting the genetic data, this fact and the possibility of the presence of different gene products should be taken into account. [Psikiyatride Guncel Yaklasimlar - Current Approaches in Psychiatry 2014; 6(3.000: 217-226

  8. Extraction of metals from metal ion-catechol-quaternary base systems.

    Science.gov (United States)

    Vrchlabský, M; Sommer, L

    1968-09-01

    Methods are given for the extraction of iron(III), molybdenum(VI), titanium(IV), niobium(V), vanadium(IV), uranium(VI) and tungsten(VI) as ternary complexes with catechol and a quaternary cation such as n-butyltriphenylphosphonium, n-propyltriphenylphosphonium, tetraphenylarsonium, cetylpyridinium, cetyltrimethylammonium and 2,3,5-triphenyltetrazolium, the solvent being chloroform. By use of masking agents and pH control, some of these elements can be separated from each other by this means.

  9. Effects of the co-carcinogen catechol on benzo(a)pyrene metabolism and DNA adduct formation in mouse skin

    Energy Technology Data Exchange (ETDEWEB)

    Melikian, A.A.; Leszczynska, J.M.; Hecht, S.S.; Hoffmann, D.

    1986-01-01

    We have studied the effects of the co-carcinogen catechol (1,2-dihydroxybenzene) on the metabolic activation of (/sup 3/H) benzo(a)pyrene (BaP) in mouse skin, in vivo and on the binding of BaP metabolites to DNA and protein at intervals from 0.5-24 h. Upon topical application of 0.015 mg (/sup 3/H)BaP and 0.25 or 0.5 mg catechol per mouse, catechol had little effect on the total amount of (/sup 3/H)BaP metabolized in mouse skin, but it affected the relative proportions of (/sup 3/H)BaP metabolites. Catechol (0.5 mg/mouse) decreased the proportion of water-soluble (/sup 3/H)BaP metabolites, ethyl acetate-soluble polar metabolites and quinones, but doubled the levels of unconjugated 3-hydroxy-BaP at all measured intervals after treatment. Catechol also caused a small increase in the levels of trans-7,8-dihydroxy-7,8-dihydroBaP and trans-9,10-dihydroxy-9,10-dihydroBaP 0.5 h after treatment. Two hours after treatment, the levels of these metabolites subsided to those of the controls. Catechol did not affect the levels of glutathione conjugates of BaP. However, it caused a decrease in glucuronide and sulphate conjugate formation from BaP. Catechol caused an approximately 2-fold increase in the formation of anti-7,8-dihydroxy-9,10-epoxy-7,8,9,10-tetrahydroBaP (BPDE) DNA adducts and elevated the ratio of anti-syn-BPDE-DNA adducts 1.6 to 2.9-fold. Catechol treatment increased the radioactivity associated with epidermal proteins after (/sup 3/H)BaP application. Because catechol increased levels of 3-hydroxyBaP, we considered the possibility that 3-hydroxyBaP might enhance the tumor initiating activities of BaP or BPDE in mouse skin; a bioassay demonstrated that this was not the case. The results of this study indicate that one important effect of catechol related to its co-carcinogenicity is its ability to enhance formation of anti-BPDE-DNA adducts in mouse skin.

  10. Magnetic catechol-chitosan with bioinspired adhesive surface: preparation and immobilization of ω-transaminase.

    Directory of Open Access Journals (Sweden)

    Kefeng Ni

    Full Text Available The magnetic chitosan nanocomposites have been studied intensively and been used practically in various biomedical and biological applications including enzyme immobilization. However, the loading capacity and the remained activity of immobilized enzyme based on existing approaches are not satisfied. Simpler and more effective immobilization strategies are needed. Here we report a simple catechol modified protocol for preparing a novel catechol-chitosan (CCS-iron oxide nanoparticles (IONPs composites carrying adhesive moieties with strong surface affinity. The ω-transaminase (ω-TA was immobilized onto this magnetic composite via nucleophilic reactions between catechol and ω-TA. Under optimal conditions, 87.5% of the available ω-TA was immobilized on the composite, yielding an enzyme loading capacity as high as 681.7 mg/g. Furthermore, the valuation of enzyme activity showed that ω-TA immobilized on CCS-IONPs displayed enhanced pH and thermal stability compared to free enzyme. Importantly, the immobilized ω-TA retained more than 50% of its initial activity after 15 repeated reaction cycles using magnetic separation and 61.5% of its initial activity after storage at 4°C in phosphate buffered saline (PBS for 15 days. The results suggested that such adhesive magnetic composites may provide an improved platform technology for bio-macromolecules immobilized.

  11. Secondary Organic Aerosol formation from the gas-phase reaction of catechol with ozone

    Science.gov (United States)

    Coeur-Tourneur, C.; Tomas, A.; Guilloteau, A.; Henry, F.; Ledoux, F.; Visez, N.; Riffault, V.; Wenger, J. C.; Bedjanian, Y.; Foulon, V.

    2009-04-01

    The formation of secondary organic aerosol from the gas-phase reaction of catechol (1,2-dihydroxybenzene) with ozone has been studied in two smog chambers (at the LPCA in France and at the CRAC in Ireland). Aerosol production was monitored using a scanning mobility particle sizer. The overall organic aerosol yield (Y) was determined as the ratio of the suspended aerosol mass corrected for wall losses (Mo) to the total reacted catechol concentrations, assuming a particle density of 1.4 g cm-3. Analysis of the data clearly shows that Y is a strong function of Mo and that secondary organic aerosol formation can be expressed by a one-product gas/particle partitioning absorption model. The aerosol formation is affected by the initial catechol concentration, which leads to aerosol yields ranging from 17% to 86%. The aerosol yields determined in the LPCA and CRAC smog chambers were comparable and were also in accordance with those determined in a previous study performed in EUPHORE (EUropean PHOto REactor, Spain).

  12. Serotonin-Induced Hypersensitivity via Inhibition of Catechol O-Methyltransferase Activity

    Directory of Open Access Journals (Sweden)

    Tsao Douglas

    2012-04-01

    Full Text Available Abstract The subcutaneous and systemic injection of serotonin reduces cutaneous and visceral pain thresholds and increases responses to noxious stimuli. Different subtypes of 5-hydroxytryptamine (5-HT receptors are suggested to be associated with different types of pain responses. Here we show that serotonin also inhibits catechol O-methyltransferase (COMT, an enzyme that contributes to modultion the perception of pain, via non-competitive binding to the site bound by catechol substrates with a binding affinity comparable to the binding affinity of catechol itself (Ki = 44 μM. Using computational modeling, biochemical tests and cellular assays we show that serotonin actively competes with the methyl donor S-adenosyl-L-methionine (SAM within the catalytic site. Binding of serotonin to the catalytic site inhibits the access of SAM, thus preventing methylation of COMT substrates. The results of in vivo animal studies show that serotonin-induced pain hypersensitivity in mice is reduced by either SAM pretreatment or by the combined administration of selective antagonists for β2- and β3-adrenergic receptors, which have been previously shown to mediate COMT-dependent pain signaling. Our results suggest that inhibition of COMT via serotonin binding contributes to pain hypersensitivity, providing additional strategies for the treatment of clinical pain conditions.

  13. Effect of Metal Ions on the Formation of Trichloronitromethane during Chlorination of Catechol and Nitrite.

    Science.gov (United States)

    Gan, Guojuan; Mei, Rongwu; Qiu, Lin; Hong, Huachang; Wang, Qingjun; Mazumder, Asit; Wu, Shikai; Pan, Xiangliang; Liang, Yan

    2016-11-01

    Catechol, nitrite, and dissolved metals are ubiquitous in source drinking water. Catechol and nitrite have been identified as precursors for halonitromethanes (HNMs), but the effect of metal ions on HNM formation during chlorination remains unclear. The main objective of this study was to investigate the effect of metal ions (Fe, Ti, Al) on the formation of trichloronitromethane (TCNM) (the most representative HNM species in disinfected water) on chlorinating catechol and nitrite. Trichloronitromethane was extracted by methyl tert-butyl ether and detected by gas chromatography. The results show that metal ions promoted the formation of TCNM and that the enhancement efficiency followed the order of Fe > Ti > Al. Trichloronitromethane formation increased greatly within 2 h, and a basic condition (pH 8-9) favored TCNM formation more than acidic or neutral conditions. The conjoint effect of the metal-ion mixtures was shown to be similar to that of the single metal ion having the highest promoting effect on TCNM formation. Our results strongly suggest that metal ions play a significant role in enhancing TCNM formation.

  14. Computational studies of catechol and water interactions with titanium oxide nanoparticles.

    Energy Technology Data Exchange (ETDEWEB)

    Redfern, P. C.; Zapol, P.; Curtiss, L. A.; Rajh, T.; Thurnauer, M.

    2003-10-16

    The interaction of catechol and water with titanium oxide nanoparticles was investigated using ab initio molecular orbital theory and density functional theory. Hydrogen-terminated TiO{sub 2} clusters were used to model the surface of anatase nanoparticles. The calculations indicate that catechol reacts with a Ti{double_bond}O defect site on the surface to form a bidentate structure that is favored over dissociative or molecular adsorption on the (101) anatase surface. The dissociative adsorption of catechol at the defect site leads to a much larger red shift in the TiO{sub 2} excitation energy than molecular adsorption on the (101) anatase surface on the basis of ZINDO/S calculations. This is consistent with recent experimental results on small (<2 nm) titania nanoparticles. The calculations on water adsorption indicate that it can also add to the Ti{double_bond}O double bond site. However, molecular adsorption of water on the (101) anatase surface is more favorable.

  15. Cloning and expression of a novel catechol-O-methyltransferase in common marmosets.

    Science.gov (United States)

    Uehara, Shotaro; Uno, Yasuhiro; Inoue, Takashi; Sasaki, Erika; Yamazaki, Hiroshi

    2017-02-04

    Catechol-O-methyltransferase (COMT) catalyzes the O-methylation of endogenous catechol amines and estrogens and exogenous catechol-type of drugs. A Parkinson's disease model of common marmoset (Callithrix jacchus) has been widely used in preclinical studies to evaluate inhibitory potential of new drug candidates on marmoset COMT. Despite COMT inhibitors could potentiate the pharmacological action of levodopa on Parkinson's disease in animal models, marmoset COMT cDNA has not yet been identified and characterized. In this study, a cDNA highly homologous to human COMT was cloned from marmoset livers. This cDNA encoded 268 amino acids containing a transmembrane region and critical amino acid residues for catalytic function. The amino acid sequences of marmoset COMT shared high sequence identity (90%) with human COMT. COMT mRNA was expressed in all five tissues tested, including brain, lung, liver, kidney and small intestine, and was more abundant in marmoset liver and kidney. Membrane-bound COMT was immunochemically detected in livers and kidneys, whereas soluble COMT was detected in livers, similar to humans. These results indicated that the molecular characteristics of marmoset COMT were generally similar to the human ortholog.

  16. Polyaniline/polysulfone composite film electrode for simultaneous determination of hydroquinone and catechol

    Energy Technology Data Exchange (ETDEWEB)

    Feng Xiaojuan, E-mail: fengxiaojuan820@yahoo.cn [Chemistry Department of HeXi University, Zhangye 734000 (China); Shi Yanlong [Chemistry Department of HeXi University, Zhangye 734000 (China); Hu Zhongai [Key Laboratory of Polymer, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer We prepared a composite film which has bi-layers with asymmetric microstructure and relatively rich porosity which provides larger surface area for electrochemical reaction. Black-Right-Pointing-Pointer The outer polysulfone layer is propitious for the organic molecules to enrich on the composite film, which brings great enhancement in electron transfer kinetics. Black-Right-Pointing-Pointer The composite film electrode can be used to detect qualitatively or quantitatively hydroquinone and catechol in the single solute or mixed systems. - Abstract: Polyaniline (PAN)/polysulfone (PSF) composite film electrodes were successfully prepared by electropolymerization using cyclic votammetry technique. The composite film electrodes show a great enhancement in electron transfer kinetics, and the separation between oxidation and reduction peaks ({Delta}E{sub p}) decreases from 200 to 35 mV for hydroquinone (H{sub 2}Q) and from 275 to 42 mV for catechol (CC) at bare Pt and composite film electrodes respectively. In their mixed systems, the redox peak of H{sub 2}Q and two pairs of redox peaks of CC on this composite film electrode could be obviously distinguished which indicates the composite film electrodes have excellent electrocatalytic activity and reversibility towards the oxidation of two diphenols (hydroquinone and catechol). The linear relationships between the peak current and concentration are observed for single solute and mixed systems within the certain concentration range, implying that the composite film electrodes have potential application in the qualitative or quantitative analysis of diphenol.

  17. Versatile tuning of supramolecular hydrogels through metal complexation of oxidation-resistant catechol-inspired ligands.

    Science.gov (United States)

    Menyo, Matthew S; Hawker, Craig J; Waite, J Herbert

    2013-11-21

    The mussel byssal cuticle employs DOPA-Fe(3+) complexation to provide strong, yet reversible crosslinking. Synthetic constructs employing this design motif based on catechol units are plagued by oxidation-driven degradation of the catechol units and the requirement for highly alkaline pH conditions leading to decreased performance and loss of supramolecular properties. Herein, a platform based on a 4-arm poly(ethylene glycol) hydrogel system is used to explore the utility of DOPA analogues such as the parent catechol and derivatives, 4-nitrocatechol (nCat) and 3-hydroxy-4-pyridinonone (HOPO), as structural crosslinking agents upon complexation with metal ions. HOPO moieties are found to hold particular promise, as robust gelation with Fe(3+) occurs at physiological pH and is found to be largely resistant to oxidative degradation. Gelation is also shown to be triggered by other biorelevant metal ions such as Al(3+), Ga(3+) and Cu(2+) which allows for tuning of the release and dissolution profiles with potential application as injectable delivery systems.

  18. Vapour-phase O-methylation of Catechol with Methanol on Ti-containing Phosphate Catalysts

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Ti-containing phosphate(Ti-P-O) catalysts with different molar ratios of P to Ti(0-2.0) were synthesized and characterized by XRD, N2-adsorption/desorption, IR and temperature-programmed desorption(TPD) methods. The catalytic properties of Ti-P-O samples in the vapor-phase O-methylation of catechol with methanol were also studied. The catechol conversion increases with the increase of the molar ratio of P to Ti in a range of 0-0.33, while a further increase in the P content leads to a decrease of the catalytic activity. Meanwhile, the selectivities of the catalysts to the main product(guaiacol) increase gradually with the increase of the molar ratio of P to Ti. The presence of relatively strong Lewis acidic and/or basic sites in the P-free catalyst should be responsible for the formation of C-alkylation products. The weak acid-base characteristics of the catalysts are favourable for the mono-O-methylation of catechol. In comparison with the Lewis acidic sites, the Br(o)nsted acidic sites on the catalysts are more active for the title reaction.

  19. Sol-Gel Synthesis of Carbon Xerogel-ZnO Composite for Detection of Catechol

    Directory of Open Access Journals (Sweden)

    Dawei Li

    2016-04-01

    Full Text Available Carbon xerogel-zinc oxide (CXZnO composites were synthesized by a simple method of sol-gel condensation polymerization of formaldehyde and resorcinol solution containing zinc salt followed by drying and thermal treatment. ZnO nanoparticles were observed to be evenly dispersed on the surfaces of the carbon xerogel microspheres. The as-prepared CXZnO composites were mixed with laccase (Lac and Nafion to obtain a mixture solution, which was further modified on an electrode surface to construct a novel biosensing platform. Finally, the prepared electrochemical biosensor was employed to detect the environmental pollutant, catechol. The analysis result was satisfactory, the sensor showed excellent electrocatalysis towards catechol with high sensitivity (31.2 µA·mM−1, a low detection limit (2.17 µM, and a wide linear range (6.91–453 µM. Moreover, the biosensor also displayed favorable repeatability, reproducibility, selectivity, and stability besides being successfully used in the trace detection of catechol existing in lake water environments.

  20. Dinuclear copper complexes with imidazole derivative ligands: a theoretical study related to catechol oxidase activity.

    Science.gov (United States)

    Martínez, Ana; Membrillo, Ingrid; Ugalde-Saldívar, Victor M; Gasque, Laura

    2012-07-19

    Catechol oxidase is a very important and interesting metalloprotein. In spite of the efforts to understand the reaction mechanism of this protein, there are important questions that remain unanswered concerning the catalytic mechanism of this enzyme. In this article, dinuclear copper compounds are used as biomimetic models of catechol oxidase to study plausible reaction paths. These dinuclear copper(II) complexes have distant metal centers (of 7.5 Å approximately) and superior catalytic activity to that of many dicopper complexes with shorter Cu-Cu distances. One mononuclear copper(II) complex is also analyzed in this investigation in order to see the influence of the two metal centers in the catalytic activity. Density functional theory calculations were performed to obtain optimized structures, vertical ionization energies, vertical electron affinities, the electrodonating power (ω(-)), the electroaccepting power (ω(+)) and the energy difference of several reaction paths. The K(M) experimental results that were previously reported compare well with the electroaccepting power (ω(+)) of the copper compounds that are included in this article, indicating that this index is useful for the interpretation of the electron transfer capacity and therefore the catalytic activity. The catechol moiety coordinates to only one Cu ion, but two metal atoms are needed in order to have a good electron acceptor capacity of the biomimetic models.

  1. Kinetic study on electrochemical oxidation of catechols in the presence of cycloheptylamine and aniline: Experiments and digital simulation

    Indian Academy of Sciences (India)

    DAVOOD NEMATOLLAHI; FATEMEH GHASEMI; SADEGH KHAZALPOUR; FAHIMEH VARMAGHANI

    2016-12-01

    Oxidative coupling reaction of some catechols has been studied by cyclic voltammetry at the glassy carbon electrode in different experimental conditions. The electrogenerated o-banzoquinone participates in a coupling reaction with anionic and dianionic forms of catechol. Based on EC mechanism, the observed homogenous rate constants of the coupling reaction of catechols were estimated by analyzing the cyclic voltammetric responses using the simulation software DIGIELCH. This paper deals with reaction of o-benzoquinones derived by the oxidation of catechol (CAT), 3-methylcatechol (3-MC), 3-methoxycatechol(3-MOC) and 3,4-dihydroxybenzoic acid (3,4-DHBA) with cycloheptylamine (a primary aliphatic amine) and aniline (a primary aromatic amine) as nucleophiles to gain mechanistic insight. The outcome indicates participation of o-benzoquinone in the Michael addition reaction with the studied primary amines. The best fit of theexperimental and simulated results was obtained for ECE mechanism. The calculated/estimated homogeneous rate constants (kobs) for Michael addition reaction were found to vary in the order CAT>3-MC>3-MOC>3,4- DHBA and CAT>3,4-DHBA>3-MC>3-MOC for cycloheptylamine and aniline, respectively. These data are in agreement with the trend of electronic properties (electron-donating/-withdrawing) of the substitutions on the catechol ring.

  2. Catechol-Functionalized Synthetic Polymer as a Dental Adhesive to Contaminated Dentin Surface for a Composite Restoration

    Science.gov (United States)

    2015-01-01

    This study reports a synthetic polymer functionalized with catechol groups as dental adhesives. We hypothesize that a catechol-functionalized polymer functions as a dental adhesive for wet dentin surfaces, potentially eliminating the complications associated with saliva contamination. We prepared a random copolymer containing catechol and methoxyethyl groups in the side chains. The mechanical and adhesive properties of the polymer to dentin surface in the presence of water and salivary components were determined. It was found that the new polymer combined with an Fe3+ additive improved bond strength of a commercial dental adhesive to artificial saliva contaminated dentin surface as compared to a control sample without the polymer. Histological analysis of the bonding structures showed no leakage pattern, probably due to the formation of Fe–catechol complexes, which reinforce the bonding structures. Cytotoxicity test showed that the polymers did not inhibit human gingival fibroblast cells proliferation. Results from this study suggest a potential to reduce failure of dental restorations due to saliva contamination using catechol-functionalized polymers as dental adhesives. PMID:26176305

  3. Crystallization and preliminary crystallographic analysis of the catechol 2,3-dioxygenase PheB from Bacillus stearothermophilus BR219

    Energy Technology Data Exchange (ETDEWEB)

    Sugimoto, Keisuke; Matsufuzi, Kazuki; Ohnuma, Hiroaki [Department of Material Chemistry, Asahikawa National College of Technology, 2-2-1-6 Shunko-dai, Asahikawa, Hokkaido 071-8142 (Japan); Senda, Miki [Japan Biological Information Research Center (JBIRC), Japan Biological Informatics Consortium (JBIC), 2-42 Aomi, Koto-ku, Tokyo 135-0064 (Japan); Fukuda, Masao [Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188 (Japan); Senda, Toshiya, E-mail: tsenda@jbirc.aist.go.jp [Biological Information Research Center (BIRC), National Institute of Advanced Industrial Science and Technology (AIST), 2-42 Aomi, Koto-ku, Tokyo (Japan); Department of Material Chemistry, Asahikawa National College of Technology, 2-2-1-6 Shunko-dai, Asahikawa, Hokkaido 071-8142 (Japan)

    2006-02-01

    PheB, an extradiol-cleaving catecholic dioxygenase, was crystallized by the hanging-drop vapour-diffusion method using PEG 4000 as a precipitant. The crystal belongs to the orthorhombic system, space group P2{sub 1}2{sub 1}2{sub 1}, and diffracts to 2.3 Å resolution. Class II extradiol-cleaving catecholic dioxygenase, a key enzyme of aromatic compound degradation in bacteria, cleaves the aromatic ring of catechol by adding two O atoms. PheB is one of the class II extradiol-cleaving catecholic dioxygenases and shows a high substrate specificity for catechol derivatives, which have one aromatic ring. In order to reveal the mechanism of the substrate specificity of PheB, PheB has been crystallized by the hanging-drop vapour-diffusion method using PEG 4000 as a precipitant. The space group of the obtained crystal was P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 65.5, b = 119.2, c = 158.7 Å. The crystal diffracted to 2.3 Å resolution.

  4. Electro-catalytic Oxidation of Catechol at Poly(1-amino-9,10-anthraquinone)-SDS Composite Film.

    Science.gov (United States)

    Nikoofard, Hossein; Solbi, Malihe

    2016-12-01

    An electro-chemically active composite film containing the environmentally friendly surfactant sodium dodecyl sulfate (SDS) and poly(1-amino-9,10-anthraquinone) (PAAQ) is used as an electron transfer mediator in the electro-chemical oxidation of catechol. Compared with the bare platinum (Pt) electrode, the Pt/PAAQ-SDS modified electrode remarkably lowers the anodic peak potential of catechol, and increases the peak currents. The results obtained indicate that the activation energy for the electro-chemical oxidation of catechol at the polymer film is low (7.05 kJ mol-1). The influence of the operational conditions on the response current of the catechol sensor is also investigated. Studying the surface morphology of the modified electrode reveals a more porous structure for it due to the incorporation of the anionic surfactant on the PAAQ film. The modified electrode displays a linear response in the concentration range of 0.01-8.0 mM for catechol. A lower detection limit was obtained to be 2.60 μM. The ability of the modified electrode is also examined for the electro-chemical detection of hydroquinone (HQ) with simplicity.

  5. Catechol-Functionalized Synthetic Polymer as a Dental Adhesive to Contaminated Dentin Surface for a Composite Restoration.

    Science.gov (United States)

    Lee, Sang-Bae; González-Cabezas, Carlos; Kim, Kwang-Mahn; Kim, Kyoung-Nam; Kuroda, Kenichi

    2015-08-10

    This study reports a synthetic polymer functionalized with catechol groups as dental adhesives. We hypothesize that a catechol-functionalized polymer functions as a dental adhesive for wet dentin surfaces, potentially eliminating the complications associated with saliva contamination. We prepared a random copolymer containing catechol and methoxyethyl groups in the side chains. The mechanical and adhesive properties of the polymer to dentin surface in the presence of water and salivary components were determined. It was found that the new polymer combined with an Fe(3+) additive improved bond strength of a commercial dental adhesive to artificial saliva contaminated dentin surface as compared to a control sample without the polymer. Histological analysis of the bonding structures showed no leakage pattern, probably due to the formation of Fe-catechol complexes, which reinforce the bonding structures. Cytotoxicity test showed that the polymers did not inhibit human gingival fibroblast cells proliferation. Results from this study suggest a potential to reduce failure of dental restorations due to saliva contamination using catechol-functionalized polymers as dental adhesives.

  6. Polymer-supported sulfonated catechol and linear catechol amide ligands and their use in selective metal ion removal and recovery from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Fish, Richard H. (Berkeley, CA)

    1997-01-01

    The present invention concerns the synthesis of several biomimetically important polymer-supported, sulfonated catechol (PS-CATS), sulfonated bis-catechol linear amide (PS-2-6-LICAMS) and sulfonated 3,3-linear tris-catechol amide (PS-3,3-LICAMS) ligands, which chemically bond to modified 6% crosslinked macroporous polystyrene-divinylbenzene beads (PS-DVB). These polymers are useful for the for selective removal and recovery of environmentally and economically important metal ions from aqueous solution, as a function of pH. The Fe.sup.3+ ion selectivity shown for PS-CATS, PS-2-6-LICAMS, and PS-3,3-LICAMS polymer beads in competition with a similar concentration of Cu.sup.2+, Zn.sup.2+, Mn.sup.2+, Ni.sup.2+,Mg.sup.2+, Al.sup.3+, and Cr.sup.3+ ions at pH 1-3. Further, the metal ion selectivity is changed at higher pH values in the absence of Fe.sup.3+ (for example, Hg.sup.2+ at pH 3). The rates of selective removal and recovery of the trivalent metal ions, e.g. Fe.sup.3+ Al.sup.3+ ion etc. with the PS-CATS, PS-2-6-LICAMS, and PS-3,3-LICAMS polymer beads use determined are useful as well as equilibrium selectivity coefficient (K.sub.m) values for all metal competition studies. The chelate effect for the predisposed octahedral PS-3,3-LICAMS polymer pendant ligand is the reason that this ligand has a more pronounced selectivity for Fe.sup.3+ ion in comparison to the PS-CATS polymer beads. The predisposed square planar PS-2-6-Mn.sup.2+, Ni.sup.2+, and Mg.sup.2+, than either PS-CATS or PS-3,3-LICAMS. However, Fe.sup.3+ ion still dominates in competition with other divalent and trivalent metal ions. In the absence of Fe.sup.3+, the polymer ligand is selective for Al.sup.3+, Cu.sup.2+ or Hg.sup.2+. The changing of the cavity size from two CH.sub.2 groups to six CH.sub.2 groups in the PS-2-6-LICAMS polymer pendant ligand series does not effect the order of metal ion selectivity.

  7. Polymer-supported sulfonated catechol and linear catechol amide ligands and their use in selective metal ion removal and recovery from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Fish, R.H.

    1997-04-22

    The present invention concerns the synthesis of several biomimetically important polymer-supported, sulfonated catechol (PS-CATS), sulfonated bis-catechol linear amide (PS-2-6-LICAMS) and sulfonated 3,3-linear tris-catechol amide (PS-3,3-LICAMS) ligands, which chemically bond to modified 6% crosslinked macroporous polystyrene-divinylbenzene beads (PS-DVB). These polymers are useful for the for selective removal and recovery of environmentally and economically important metal ions from aqueous solution, as a function of pH. The Fe{sup 3+} ion selectivity shown for PS-CATS, PS-2-6-LICAMS, and PS-3,3-LICAMS polymer beads in competition with a similar concentration of Cu{sup 2+}, Zn{sup 2+}, Mn{sup 2+}, Ni{sup 2+}, Mg{sup 2+}, Al{sup 3+}, and Cr{sup 3+} ions at pH 1--3. Further, the metal ion selectivity is changed at higher pH values in the absence of Fe{sup 3+} (for example, Hg{sup 2+} at pH 3). The rates of selective removal and recovery of the trivalent metal ions, e.g. Fe{sup 3+}, Al{sup 3+} ion etc. with the PS-CATS, PS-2-6-LICAMS, and PS-3,3-LICAMS polymer beads use determined are useful as well as equilibrium selectivity coefficient (K{sub m}) values for all metal competition studies. The chelate effect for the predisposed octahedral PS-3,3-LICAMS polymer pendant ligand is the reason that this ligand has a more pronounced selectivity for Fe{sup 3+} ion in comparison to the PS-CATS polymer beads. The predisposed square planar PS-2-6-Mn{sup 2+}, Ni{sup 2+}, and Mg{sup 2+}, than either PS-CATS or PS-3,3-LICAMS. However, Fe{sup 3+} ion still dominates in competition with other divalent and trivalent metal ions. In the absence of Fe{sup 3+}, the polymer ligand is selective for Al{sup 3+}, Cu{sup 2+} or Hg{sup 2+}. The changing of the cavity size from two CH{sub 2} groups to six CH{sub 2} groups in the PS-2-6-LICAMS polymer pendant ligand series does not effect the order of metal ion selectivity. 9 figs.

  8. Polymer-supported sulfonated catechol and linear catechol amide ligands and their use in selective metal ion removal recovery from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Fish, R.H.

    1998-11-10

    The present invention concerns the synthesis of several biomimetically important polymer-supported, sulfonated catechol (PS-CATS), sulfonated bis-catechol linear amide (PS-2-6-LICAMS) and sulfonated 3,3-linear tris-catechol amide (PS-3,3-LICAMS) ligands, which chemically bond to modified 6% crosslinked macroporous polystyrene-divinylbenzene beads (PS-DVB). These polymers are useful for the for selective removal and recovery of environmentally and economically important metal ions from aqueous solution, as a function of pH. The Fe{sup 3+} ion selectivity shown for PS-CATS, PS-2-6-LICAMS, and PS-3,3-LICAMS polymer beads in competition with a similar concentration of Cu{sup 2+}, Zn{sup 2+}, Mn{sup 2+}, Ni{sup 2+}, Mg{sup 2+}, Al{sup 3+}, and Cr{sup 3+} ions at pH 1--3. Further, the metal ion selectivity is changed at higher pH values in the absence of Fe{sup 3+} (for example, Hg{sup 2+} at pH 3). The rates of selective removal and recovery of the trivalent metal ions, e.g. Fe{sup 3+}, Al{sup 3+} ion etc. with the PS-CATS, PS-2-6-LICAMS, and PS-3,3-LICAMS polymer beads used determined are useful as well as equilibrium selectivity coefficient (K{sub m}) values for all metal competition studies. The chelate effect for the predisposed octahedral PS-3,3-LICAMS polymer pendant ligand is the reason that this ligand has a more pronounced selectivity for Fe{sup 3+} ion in comparison to the PS-CATS polymer beads. The predisposed square planar PS-2,6-LICAMS series of polymer pendant ligands are more selective to divalent metal ions Cu{sup 2+}, Zn{sup 2+}, Mn{sup 2+}, Ni{sup 2+}, and Mg{sup 2+}, than either PS-CATS or PS-3,3-LICAMS. However, Fe{sup 3+} ion still dominates in competition with other divalent and trivalent metal ions. In the absence of Fe{sup 3+}, the polymer ligand is selective for Al{sup 3+}, Cu{sup 2+} or Hg{sup 2+}. The changing of the cavity size from two CH{sub 2} groups to six CH{sub 2} groups in the PS-2-6-LICAMS polymer pendant ligand series does not effect

  9. Polymer-supported sulfonated catechol and linear catechol amide ligands and their use in selective metal ion removal recovery from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Fish, Richard H. (Berkeley, CA)

    1998-01-01

    The present invention concerns the synthesis of several biomimetically important polymer-supported, sulfonated catechol (PS-CATS), sulfonated bis-catechol linear amide (PS-2-6-LICAMS) and sulfonated 3,3-linear tris-catechol amide (PS-3,3-LICAMS) ligands, which chemically bond to modified 6% crosslinked macroporous polystyrene-divinylbenzene beads (PS-DVB). These polymers are useful for the for selective removal and recovery of environmentally and economically important metal ions from aqueous solution, as a function of pH. The Fe.sup.3+ ion selectivity shown for PS-CATS, PS-2-6-LICAMS, and PS-3,3-LICAMS polymer beads in competition with a similar concentration of Cu.sup.2+, Zn.sup.2+, Mn.sup.2+, Ni.sup.2+, Mg.sup.2+, Al.sup.3+, and Cr.sup.3+ ions at pH 1-3. Further, the metal ion selectivity is changed at higher pH values in the absence of Fe.sup.3+ (for example, Hg.sup.2+ at pH 3). The rates of selective removal and recovery of the trivalent metal ions, e.g. Fe.sup.3+ Al.sup.3+ ion etc. with the PS-CATS, PS-2-6-LICAMS, and PS-3,3-LICAMS polymer beads used determined are useful as well as equilibrium selectivity coefficient (K.sub.m) values for all metal competition studies. The chelate effect for the predisposed octahedral PS-3,3-LICAMS polymer pendant ligand is the reason that this ligand has a more pronounced selectivity for Fe.sup.3+ ion in comparison to the PS-CATS polymer beads. The predisposed square planar PS-2,6-LICAMS series of polymer pendant ligands are more selective to divalent metal ions Cu.sup.2+, Zn.sup.2+, Mn.sup.2+, Ni.sup.2+, and Mg.sup.2+, than either PS-CATS or PS-3,3-LICAMS. However, Fe.sup.3+ ion still dominates in competition with other divalent and trivalent metal ions. In the absence of Fe.sup.3+, the polymer ligand is selective for Al.sup.3+, Cu.sup.2+ or Hg.sup.2+. The changing of the cavity size from two CH.sub.2 groups to six CH.sub.2 groups in the PS-2-6-LICAMS polymer pendant ligand series does not effect the order of metal ion

  10. Kinetic and mechanism of atmospheric degradation of three volatile organics compounds: acetone, phenol and catechol; Cinetique et mecanisme de degradation atmospherique de trois composes organiques volatils: l'acetone, le phenol et le catechol

    Energy Technology Data Exchange (ETDEWEB)

    Turpin, E.

    2004-12-01

    In this thesis, atmospheric degradation of three VOC (volatile organic compound), acetone, phenol and catechol, has been studied. These compounds are renowned to be some of main compounds in the atmosphere because the relative importance of their primary emissions (biogenic, gas fumes,...) and secondary emissions (VOCs oxidation). This work has been realised in two laboratories using two complementary devices. These instruments are the fast flow tube with LIF (laser induce fluorescence) and a smog Teflon chamber with gas-phase chromatography with FTIR, FID, MS. The both use of these techniques enable to determine the main pathway of the acetone oxidation with OH radical. The smog chamber's studies of the phenol and catechol reactions with OH radical enable to determine some relative rate constants and mechanisms. It's the first mechanism proposition for the catechol + OH radical reaction. These obtained results have been used to mention the atmospheric impact of these compounds. (author)

  11. Biomimetic PEG-catecholates for stabile antifouling coatings on metal surfaces: applications on TiO2 and stainless steel.

    Science.gov (United States)

    Khalil, Faiza; Franzmann, Elisa; Ramcke, Julian; Dakischew, Olga; Lips, Katrin S; Reinhardt, Alexander; Heisig, Peter; Maison, Wolfgang

    2014-05-01

    Trimeric catecholates have been designed for the stable immobilization of effector molecules on metal surfaces. The design of these catecholates followed a biomimetic approach and was inspired by natural multivalent metal binders, such as mussel adhesion proteins (MAPs) and siderophores. Three catecholates have been conjugated to central scaffolds based on adamantyl or trisalkylmethyl core structures. The resulting triscatecholates have been immobilized on TiO2 and stainless steel. In a proof of concept study we have demonstrated the high stability of the resulting nanolayers at neutral and slightly acidic pH. Furthermore, polyethylene glycol (PEG) conjugates of our triscatecholates have been synthesized and were immobilized on TiO2 and stainless steel. The PEG coated surfaces showed excellent antifouling properties upon exposure to human blood and bacteria as demonstrated by fluorescence microscopy, ellipsometry and a bacterial assay with Staphylococcus epidermidis. In addition, our PEG-triscatecholates showed no cytotoxicity against bone-marrow stem cells on TiO2.

  12. Mechanochemical transformation of an organic ligand on mineral surfaces: The efficiency of birnessite in catechol degradation

    Energy Technology Data Exchange (ETDEWEB)

    Di Leo, Paola, E-mail: pdileo@imaa.cnr.it [Consiglio Nazionale delle Ricerche - Istituto di Metodologie per l' Analisi Ambientale, C.da S. Loja, Zona Industriale, 85050 Tito Scalo (PZ) (Italy); Pizzigallo, Maria Donata Rosa [Dipartimento di Biologia e Chimica Agroforestale e Ambientale, Universita di Bari Aldo Moro, Via Amendola 165/a, 70126 Bari (Italy); Ancona, Valeria [Consiglio Nazionale delle Ricerche - Istituto di Ricerca sulle Acque, Via F. De Blasio 5, 70132 Bari (Italy); Di Benedetto, Francesco [Dipartimento di Chimica, Universita di Firenze, Via della Lastruccia, 3, 50019 Sesto Fiorentino (Italy); Mesto, Ernesto; Schingaro, Emanuela; Ventruti, Gennaro [Dipartimento di Scienze della Terra e Geoambientali, Universita di Bari Aldo Moro, Via Orabona, 4, 70125 Bari (Italy)

    2012-01-30

    Graphical abstract: . The efficiency of mechanochemical treatments in degrading CAT molecules in presence of the highly reactive phyllomanganate birnessite, and without using organic solvents, has been demonstrated in the present study. Integrating information from different techniques on solid let it possible to get a comprehensive picture of the most reliable reaction mechanism of degradation of CAT molecules onto KBi surfaces, thus allowing the individuation of specific sites in the synthesized oxides on which catechol molecules were preferentially adsorbed, and thus degraded. The degradation mechanism mainly occurs via a redox reaction. It implies the formation of a surface bidentate inner-sphere complex between the phenolic group of the organic molecules and the Mn(IV) from the birnessite structure. Structural changes occur on the MnO{sub 6} layers of birnessite as due to the mechanically induced surface reactions: reduction of Mn(IV), consequent formation of Mn(III) and new vacancies, and free Mn{sup 2+} ions production. The extent of the mechanochemical degradation of CAT onto birnessite surfaces is higher. This is a consequence of the two phenolic groups of catechol that easily reacts. Highlights: Black-Right-Pointing-Pointer A basic insight at molecular scale of the mechanically induced transformations of CAT onto birnessite is obtained. Black-Right-Pointing-Pointer The abiotic degradative mechanisms of CAT onto birnessite is provided. Black-Right-Pointing-Pointer The mechanically induced degradation of CAT mainly occurs via a redox reaction. Black-Right-Pointing-Pointer Mechanochemistry improves the efficiency of birnessite to degrade CAT. Black-Right-Pointing-Pointer The mechanochemical technique offer potentials in remediating contaminated sites. - Abstract: The aim of this work is to investigate the efficiency of the phyllomanganate birnessite in degrading catechol after mechanochemical treatments. A synthesized birnessite and the organic molecule were

  13. Electrochemical sensor for catechol and dopamine based on a catalytic molecularly imprinted polymer-conducting polymer hybrid recognition element.

    Science.gov (United States)

    Lakshmi, Dhana; Bossi, Alessandra; Whitcombe, Michael J; Chianella, Iva; Fowler, Steven A; Subrahmanyam, Sreenath; Piletska, Elena V; Piletsky, Sergey A

    2009-05-01

    One of the difficulties with using molecularly imprinted polymers (MIPs) and other electrically insulating materials as the recognition element in electrochemical sensors is the lack of a direct path for the conduction of electrons from the active sites to the electrode. We have sought to address this problem through the preparation and characterization of novel hybrid materials combining a catalytic MIP, capable of oxidizing the template, catechol, with an electrically conducting polymer. In this way a network of "molecular wires" assists in the conduction of electrons from the active sites within the MIP to the electrode surface. This was made possible by the design of a new monomer that combines orthogonal polymerizable functionality; comprising an aniline group and a methacrylamide. Conducting films were prepared on the surface of electrodes (Au on glass) by electropolymerization of the aniline moiety. A layer of MIP was photochemically grafted over the polyaniline, via N,N'-diethyldithiocarbamic acid benzyl ester (iniferter) activation of the methacrylamide groups. Detection of catechol by the hybrid-MIP sensor was found to be specific, and catechol oxidation was detected by cyclic voltammetry at the optimized operating conditions: potential range -0.6 V to +0.8 V (vs Ag/AgCl), scan rate 50 mV/s, PBS pH 7.4. The calibration curve for catechol was found to be linear to 144 microM, with a limit of detection of 228 nM. Catechol and dopamine were detected by the sensor, whereas analogues and potentially interfering compounds, including phenol, resorcinol, hydroquinone, serotonin, and ascorbic acid, had minimal effect (< or = 3%) on the detection of either analyte. Non-imprinted hybrid electrodes and bare gold electrodes failed to give any response to catechol at concentrations below 0.5 mM. Finally, the catalytic properties of the sensor were characterized by chronoamperometry and were found to be consistent with Michaelis-Menten kinetics.

  14. Catechol-O-Methyltransferase and 3,4-(±)-Methylenedioxymethamphetamine Toxicity

    Science.gov (United States)

    Herndon, Joseph M.; Cholanians, Aram B.; Lizarraga, Lucina E.; Lau, Serrine S.; Monks, Terrence J.

    2014-01-01

    Metabolism of 3,4-(±)-methylenedioxymethamphetamine (MDMA) is necessary to elicit its neurotoxic effects. Perturbations in phase I and phase II hepatic enzymes can alter the neurotoxic profile of systemically administered MDMA. In particular, catechol-O-methyltransferase (COMT) plays a critical role in determining the fraction of MDMA that is converted to potentially neurotoxic metabolites. Thus, cytochrome P450 mediated demethylenation of MDMA, or its N-demethylated metabolite, 3,4-(±)-methylenedioxyamphetamine, give rise to the catechols, N-methyl-α-methyldopamine and α-methyldopamine, respectively. Methylation of these catechols by COMT limits their oxidation and conjugation to glutathione, a process that ultimately gives rise to neurotoxic metabolites. We therefore determined the effects of modulating COMT, a critical enzyme involved in determining the fraction of MDMA that is converted to potentially neurotoxic metabolites, on MDMA-induced toxicity. Pharmacological inhibition of COMT in the rat potentiated MDMA-induced serotonin deficits and exacerbated the acute MDMA-induced hyperthermic response. Using a genetic mouse model of COMT deficiency, in which mice lack a functional COMT gene, such mice displayed greater reductions in dopamine concentrations relative to their wild-type (WT) counterparts. Neither WT nor COMT deficient mice were susceptible to MDMA-induced decreases in serotonin concentrations. Interestingly, mice devoid of COMT were far more susceptible to the acute hyperthermic effects of MDMA, exhibiting greater increases in body temperature that ultimately resulted in death. Our findings support the view that COMT plays a pivotal role in determining the toxic response to MDMA. PMID:24591155

  15. Phorbol myristate acetate and catechol as skin cocarcinogens in SENCAR mice

    Energy Technology Data Exchange (ETDEWEB)

    Van Duuren, B.L.; Melchionne, S.; Seidman, I.

    1986-09-01

    The enhancement of the carcinogenicity of benzo(a) pyrene (B(a)P) and ..beta..-propiolactone (BPL) by the mouse skin cocarcinogens phorbol myristate acetate (PMA) and catechol were examined in female SENCAR mice, 30 per group. The carcinogen and cocarcinogen were applied simultaneously, three times weekly for 490-560 days. B(a)P and BPL were used at constant doses of 5 and 50 ..mu..g, respectively, in all experiments. PMA was used at three doses, 2.5, 1.0, and 0.5 ..mu..g per application, and catechol was used at one dose, 2 mg per application. Control groups included animals that received carcinogen only, cocarcinogen only, acetone only, and no treatment. The carcinogenicity of B(a)P and BPL were enhanced by the cocarcinogens, particularly in terms of tumor multiplicity. For both carcinogens, the most marked cocarcinogenic effects were observed at the lowest dose of PMA used (0.5 ..mu..g per application). This observation applied for days to first tumor, animals with tumors, tumor multiplicity, and incidence of malignant skin tumors. Catechol applied alone did not induce any tumors; with PMA alone there were significant incidences of benign and malignant tumors, e.g., at a dose of only 0.5 ..mu..g per application, 15 of 30 animals had 28 tumors, 5 of which were squamous carcinomas. In two-stage carcinogenesis experiments with 7,12-dimethylbenz(a)anthracene (DMBA) as initiator and PMA as promoter, SENCAR mice showed a greater susceptibility to tumor induction when compared to ICR/Ha mice used in earlier work. This susceptibility was most notable in terms of rate of tumor appearance and tumor multiplicity.

  16. Facile fabrication of gold nanoparticle on zein ultrafine fibers and their application for catechol biosensor

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xiaodong; Li, Dawei; Li, Guohui; Luo, Lei; Ullah, Naseeb; Wei, Qufu, E-mail: qfwei@jiangnan.edu.cn; Huang, Fenglin, E-mail: flhuang@jiangnan.edu.cn

    2015-02-15

    Graphical abstract: (A) Formation mechanism of A-CZNF and (B) reaction principle and formation mechanism of A-CZUF biosensor. - Highlights: • We utilized the hydrophobic protein nanofibers to fabricate a laccase-based biosensor for the first time. • The composite containing gold nanoparticles was prepared by combining electrospinning and one-step reduction method, which is a novel nanomaterial. • It is noticeable that the laccase biosensor showed a high electrochemical response and electrochemical activity toward catechol. • The novel biosensor will offer a simple, convenient and high efficient method for detecting polyphenolic compounds in environment. - Abstract: A novel laccase biosensor based on a new composite of laccase–gold nanoparticles (Au NPs)-crosslinked zein ultrafine fibers (CZUF) has been fabricated for catechol determination in real solution samples. Firstly, crosslinked zein ultrafine fibers containing gold nanoparticles (A-CZUF) were prepared by combining electrospinning and one-step reduction method using poly(ethyleneimine) (PEI) as reducing and crosslinking agent. A smooth morphology and relative average distribution of A-CZUF were depicted by scanning electron microscope (SEM) and transmission electron microscopy (TEM). The Fourier transform infrared spectroscopy (FT-IR) analysis indicated that PEI molecules attached to the surface of the zein ultrafine fibers via the reaction of functional groups between PEI and glyoxal. The results obtained from ultraviolet visible spectroscopy (UV–vis spectroscopy), X-ray diffraction (XRD) and thermal gravimetric analysis (TGA) for A-CZUF confirmed the existence of Au NPS coated on the surface of CZUF. Square wave voltammetry (SWV) and cyclic voltammetry (CV) were used to detect the electrochemical performance of the proposed biosensor. The results demonstrated that this biosensor possessed a high sensitive detection to catechol, which was attributed to the direct electron transfer (DET

  17. pH Responsive and Oxidation Resistant Wet Adhesive based on Reversible Catechol-Boronate Complexation.

    Science.gov (United States)

    Narkar, Ameya R; Barker, Brett; Clisch, Matthew; Jiang, Jingfeng; Lee, Bruce P

    2016-08-09

    A smart adhesive capable of binding to a wetted surface was prepared by copolymerizing dopamine methacrylamide (DMA) and 3-acrylamido phenylboronic acid (AAPBA). pH was used to control the oxidation state and the adhesive property of the catechol side chain of DMA and to trigger the catechol-boronate complexation. FTIR spectroscopy confirmed the formation of the complex at pH 9, which was not present at pH 3. The formation of the catechol-boronate complex increased the cross-linking density of the adhesive network. Most notably, the loss modulus values of the adhesive were more than an order of magnitude higher for adhesive incubated at pH 9 when compared to those measured at pH 3. This drastic increase in the viscous dissipation property is attributed to the introduction of reversible complexation into the adhesive network. Based on the Johnson Kendall Roberts (JKR) contact mechanics test, adhesive containing both DMA and AAPBA demonstrated strong interfacial binding properties (work of adhesion (Wadh) = 2000 mJ/m(2)) to borosilicate glass wetted with an acidic solution (pH 3). When the pH was increased to 9, Wadh values (180 mJ/m(2)) decreased by more than an order of magnitude. During successive contact cycles, the adhesive demonstrated the capability to transition reversibly between its adhesive and nonadhesive states with changing pH. Adhesive containing only DMA responded slowly to repeated changes in pH and became progressively oxidized without the protection of boronic acid. Although adhesive containing only AAPBA also demonstrated strong wet adhesion (Wadh ∼ 500 mJ/m(2)), its adhesive properties were not pH responsive. Both DMA and AAPBA are required to fabricate a smart adhesive with tunable and reversible adhesive properties.

  18. Synthesis and optimization of N-heterocyclic pyridinones as catechol-O-methyltransferase (COMT) inhibitors.

    Science.gov (United States)

    Zhao, Zhijian; Harrison, Scott T; Schubert, Jeffrey W; Sanders, John M; Polsky-Fisher, Stacey; Zhang, Nanyan Rena; McLoughlin, Debra; Gibson, Christopher R; Robinson, Ronald G; Sachs, Nancy A; Kandebo, Monika; Yao, Lihang; Smith, Sean M; Hutson, Pete H; Wolkenberg, Scott E; Barrow, James C

    2016-06-15

    A series of N-heterocyclic pyridinone catechol-O-methyltransferase (COMT) inhibitors were synthesized. Physicochemical properties, including ligand lipophilic efficiency (LLE) and clogP, were used to guide compound design and attempt to improve inhibitor pharmacokinetics. Incorporation of heterocyclic central rings provided improvements in physicochemical parameters but did not significantly reduce in vitro or in vivo clearance. Nevertheless, compound 11 was identified as a potent inhibitor with sufficient in vivo exposure to significantly affect the dopamine metabolites homovanillic acid (HVA) and dihydroxyphenylacetic acid (DOPAC), and indicate central COMT inhibition.

  19. Application of p-toluidine in chromogenic detection of catechol and protocatechuate, diphenolic intermediates in catabolism of aromatic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Parke, D. (Yale Univ., New Haven, CT (United States))

    1992-08-01

    In the presence of p-toluidine and iron, protocatechuate and catechols yield color. Inclusion of p-toluidine in media facilities the screening of microbial strains for alterations affecting aromatic catabolism. Such strains include mutants affected in the expression of oxygenases and Escherichia coli colonies carrying cloned or subcloned aromatic catabolic genes which encode enzymes giving rise to protocatechuate or catechol. The diphenolic detection system can also be applied to the creation of vectors relying on insertion of cloned DNA into one of the latter marker genes.

  20. Catechol-based layer-by-layer assembly of composite coatings: a versatile platform to hierarchical nano-materials.

    Science.gov (United States)

    Wang, C X; Braendle, A; Menyo, M S; Pester, C W; Perl, E E; Arias, I; Hawker, C J; Klinger, D

    2015-08-21

    Inspired by the marine mussel's ability to adhere to surfaces underwater, an aqueous catechol-based dip coating platform was developed. Using a catechol-functionalized polyacrylamide binder in combination with inorganic nanoparticles enables the facile fabrication of robust composite coatings via a layer-by-layer process. This modular assembly of well-defined building blocks provides a versatile alternative to electrostatic driven approaches with layer thickness and refractive indices being readily tunable. The platform nature of this approach enables the fabrication of hierarchically ordered nano-materials such as Bragg stacks.

  1. Electrochemical Investigation of Catechol at Poly(niacinamide Modified Carbon Paste Electrode: A Voltammetric Study

    Directory of Open Access Journals (Sweden)

    A. B. Teradale

    2016-01-01

    Full Text Available A polymeric thin film modified electrode, that is, poly(niacinamide modified carbon paste electrode (MCPE, was developed for the electrochemical determination of catechol (CC by using cyclic voltammetric technique. Compared to bare carbon paste electrode (BCPE, the poly(niacinamide MCPE shows good electrocatalytic activity towards the oxidation of catechol in phosphate buffer solution (PBS of physiological pH 7.4. All experimental parameters were optimized. Poly(niacinamide modified carbon paste electrode gave a linear response between concentration of CC and its anodic peak current in the range within 20.6–229.0 μM. The limit of detection (3S/M and limit of quantification (10S/M were 1.497 μM and 4.99 μM, respectively. From the study of scan rate variation, the electrode process was found to be adsorption-controlled. The involvement of protons and electrons in the oxidation of CC was found to be equal. The probable electropolymerisation mechanism of niacinamide was proposed. Finally, this method can be used in development of a sensor for sensitive determination of CC.

  2. Single micelle force microscopy reveals the coordination interaction between catechol and Fe33+

    Science.gov (United States)

    Li, Yiran; Cao, Yi; Wang, Wei

    Metal coordination bonds are widely found in natural adhesive, load-bearing, and protective materials, which are thought to be responsible for their high strength and toughness. However, it remains unknown how the metal-ligand complexes could give rise to such superb mechanical properties. Here, combining single molecule force spectroscopy and quantum calculation, we study the mechanical properties of individual catechol-Fe3 + complexes, the key elements accounting for the high toughness and extensibility of byssal threads of marine mussels. We find that catechol-Fe3 + complexes possess a unique combination of mechanical features, including high mechanical stability, fast reformation kinetics, and stoichiometry-dependent mechanics. Therefore, they can serve as sacrificial bonds to efficiently dissipate energy in the material, quickly recover the mechanical properties when load is released, and be responsive to environmental conditions. Our study provides the mechanistic understanding of the coordination bond-mediated mechanical properties of biogenetic materials, and could guide future rational design and regulation of the mechanical properties of synthetic materials.

  3. Human catechol-O-methyltransferase: Cloning and expression of the membrane-associated form

    Energy Technology Data Exchange (ETDEWEB)

    Bertocci, B.; Miggiano, V.; Da Prada, M.; Dembic, Z.; Lahm, H.W.; Malherbe, P. (F. Hoffmann-La Roche Ltd., Basel (Switzerland))

    1991-02-15

    A cDNA clone for human catechol-O-methyltransferase was isolated from a human hepatoma cell line (Hep G2) cDNA library by hybridization screening with a porcine cDNA probe. The cDNA clone was sequenced and found to have an insert of 1226 nucleotides. The deduced primary structure of hCOMT is composed of 271 amino acid residues with the predicted molecular mass of 30 kDa. At its N terminus it has a hydrophobic segment of 21 amino acid residues that may be responsible for insertion of hCOMT into the endoplasmic reticulum membrane. The primary structure of hCOMT exhibits high homology to the porcine partial cDNA sequence (93%). The deduced amino acid sequence contains two tryptic peptide sequences (T-22, T-33) found in porcine liver catechol-O-methyltransferase (CEMT). The coding region of hCOMT cDNA was placed under the control of the cytomegalovirus promoter to transfect human kidney 293 cells. The recombinant hCOMT was shown by immunoblot analysis to be mainly associated with the membrane fraction. RNA blot analysis revealed one COMT mRNA transcript of 1.4 kilobases in Hep G2 poly(A){sup +} RNA.

  4. Facile fabrication of gold nanoparticle on zein ultrafine fibers and their application for catechol biosensor

    Science.gov (United States)

    Chen, Xiaodong; Li, Dawei; Li, Guohui; Luo, Lei; Ullah, Naseeb; Wei, Qufu; Huang, Fenglin

    2015-02-01

    A novel laccase biosensor based on a new composite of laccase-gold nanoparticles (Au NPs)-crosslinked zein ultrafine fibers (CZUF) has been fabricated for catechol determination in real solution samples. Firstly, crosslinked zein ultrafine fibers containing gold nanoparticles (A-CZUF) were prepared by combining electrospinning and one-step reduction method using poly(ethyleneimine) (PEI) as reducing and crosslinking agent. A smooth morphology and relative average distribution of A-CZUF were depicted by scanning electron microscope (SEM) and transmission electron microscopy (TEM). The Fourier transform infrared spectroscopy (FT-IR) analysis indicated that PEI molecules attached to the surface of the zein ultrafine fibers via the reaction of functional groups between PEI and glyoxal. The results obtained from ultraviolet visible spectroscopy (UV-vis spectroscopy), X-ray diffraction (XRD) and thermal gravimetric analysis (TGA) for A-CZUF confirmed the existence of Au NPS coated on the surface of CZUF. Square wave voltammetry (SWV) and cyclic voltammetry (CV) were used to detect the electrochemical performance of the proposed biosensor. The results demonstrated that this biosensor possessed a high sensitive detection to catechol, which was attributed to the direct electron transfer (DET) facilitated by Au NPs and high catalytic ability obtained from laccase. In addition, the proposed biosensor exhibited good reproducibility, stability and selectivity.

  5. Suicide inactivation of catechol 2,3-dioxygenase from Pseudomonas putida mt-2 by 3-halocatechols

    Energy Technology Data Exchange (ETDEWEB)

    Bartels, I.; Knackmuss, H.J.; Reineke, W.

    1984-03-01

    The inactivation of catechol 2,3-dioxygenase from Pseudomonas putida mt-2 by 3-chloro- and 3-fluorocatechol and the iron-chelating agent Tiron (catechol-3,5-disulfonate) was studied. Whereas inactivation by Tiron is an oxygen-independent and mostly reversible process, inactivation by the 3-halocatechols was only observed in the presence of oxygen and was largely irreversible. The rate constants for inactivation (K/sub 2/) were 1.62 x 10/sup -3/ sec/sup -1/ for 3-chlorocatechol and 2.38 x 10/sup -3/ sec/sup -1/ for 3-fluorocatechol. The inhibitor constants (K/sub i/) were 23 ..mu..M for 3-chlorocatechol and 17 ..mu..M for 3-fluorocatechol. The kinetic data for 3-fluorocatechol could only be obtained in the presence of 2-mercaptoethanol. Besides inactivated enzyme, some 2-hydroxyhexa-2,4-dienoic acid as the actual suicide product of meta-cleavage. A side product of 3-fluorocatechol cleavage is a yellow compound with the spectral characteristics of a 2-hydroxy-6-oxohexa-2,4-dienoci acid indicating 1,6-cleavage. Rates of inactivation by 3-fluorocatechol were reduced in the presence of superoxide dismutase, catalase, formate, and mannitol, which implies that superoxide anion, hydrogen peroxide, and hydroxyl radical exhibit additional inactivation. 64 references.

  6. Coordination chemistry of microbial iron transport compounds. IX. Stability constants for catechol models of enterobactin

    Energy Technology Data Exchange (ETDEWEB)

    Avdeef, A.; Sofen, S.R.; Bregante, T.L.; Raymond, K.N.

    1978-08-16

    The stability constants of ferric complexes with several substituted catechol (1,2-dihydroxybenzene) ligands in aqueous solutions of low ionic strength have been determined at 27/sup 0/C in the pH range 2 to 11. Enterobactin, the principal siderophore of enteric bacteria, is a tricatechol and, from the formation constants reported here, is estimated to have a formation constant with ferric ion which is greater than 10/sup 45/. The stepwise formation constants, K/sub n/, of the catechol ligands reported here are defined as (ML/sub n/)/(ML/sub n-1/)(L), in units of L mol/sup -1/, where (L) is the concentration of the deprotonated catechol ligand. The constants were determined from potentiometric and spectroscopic data and were refined on pH values by weighted least squares. Qualitative examination of electron spin resonance spectra of the systems indicated some oxidation of the ligand by ferric ions at pH values as high as 4. The ligands studied included catechol (cat) (log K/sub 1/ = 20.01, log K/sub 2/ = 14.69, log K/sub 3/ = 9.01); 4,5-dihydroxy-m-benzenedisulfonate (Tiron) (log K/sub 2/ = 15.12, log K/sub 3/ = 10.10); 4-nitrocatechol (ncat) (log K/sub 1/ = 17.08, log K/sub 2/ = 13.43, log K/sub 3/ = 9.51); 3,4-dihydroxyphenylacetic acid (dhpa) (log K/sub 1/ = 20.1, log K/sub 2/ = 14.9, log K/sub 3/ = 9.0); and 2,3-dihydroxybenzoic acid (dhba) (log K/sub 1/ = 20.5). The acid dissociation constants, K/sub a/s, were determined also. For the catechol protons these follow: cat (pK/sub a/sub 1// = 9.22, pK/sub a/sub 2// = 13.0); Tiron (pK/sub a/sub 1// = 7.70, pK/sub a/sub 2// = 12.63); ncat (pK/sub a/sub 1// = 6.65, pK/sub a/sub 2// = 10.80); dhpa (pK/sub a/sub 1// = 9.49, pK/sub a/sub 2// = 13.7); and dhba (pK/sub a/sub 1// = 10.06, pK/sub a/sub 2// = 13.1). In addition, carboxylate substituents of dhpa and dhba have pK/sub a/s of 4.17 and 2.70, respectively.In solution, exchange is slow between these two types of coordination following changes in pH. 2 tables, 11

  7. Correlation between bonding geometry and band gap states at organic-inorganic interfaces: catechol on rutile TiO{sub 2}(110)

    Energy Technology Data Exchange (ETDEWEB)

    Selloni, Annabella; Wang, Jian-Guo; Gong, Xue-Qing [Department of Chemistry, Princeton University, Princeton, NJ (United States); Li, Shao-Chun; Jacobson, Peter; Diebold, Ulrike [Department of Physics, Tulane University, New Orleans, LA (United States)

    2009-07-01

    Adsorbate-induced band gap states in semiconductors are of particular interest due to the potential of increased light absorption and photoreactivity. A combined theoretical and experimental (STM, photoemission) study of the molecular-scale factors involved in the formation of gap states in TiO{sub 2} is presented. Using the organic catechol on rutile TiO{sub 2}(110) as a model system it is found that the bonding geometry strongly affects the molecular electronic structure. At saturation catechol forms an ordered 4x1 overlayer. This structure is attributed to catechol adsorbed on rows of surface Ti atoms with the molecular plane tilted from the surface normal in an alternating fashion. In the computed lowest-energy structure one of the two terminal OH groups at each catechol dissociates and the O binds to a surface Ti atom in a monodentate configuration, while the other OH group forms a H-bond to the next catechol neighbor. Through proton exchange with the surface this structure can easily transform into one where both OH groups dissociate and the catechol is bound to two surface Ti in a bidentate configuration. Only bidendate catechol introduces states in the band gap of TiO{sub 2}.

  8. Correlation between bonding geometry and band gap states at organic-inorganic interfaces: catechol on rutile TiO2(110).

    Science.gov (United States)

    Li, Shao-Chun; Wang, Jian-guo; Jacobson, Peter; Gong, X-Q; Selloni, Annabella; Diebold, Ulrike

    2009-01-28

    Adsorbate-induced band gap states in semiconductors are of particular interest due to the potential of increased light absorption and photoreactivity. A combined theoretical and experimental (STM, photoemission) study of the molecular-scale factors involved in the formation of gap states in TiO(2) is presented. Using the organic catechol on rutile TiO(2)(110) as a model system, it is found that the bonding geometry strongly affects the molecular electronic structure. At saturation catechol forms an ordered 4 x 1 overlayer. This structure is attributed to catechol adsorbed on rows of surface Ti atoms with the molecular plane tilted from the surface normal in an alternating fashion. In the computed lowest-energy structure, one of the two terminal OH groups at each catechol dissociates and the O binds to a surface Ti atom in a monodentate configuration, whereas the other OH group forms an H-bond to the next catechol neighbor. Through proton exchange with the surface, this structure can easily transform into one where both OH groups dissociate and the catechol is bound to two surface Ti in a bidentate configuration. Only bidendate catechol introduces states in the band gap of TiO(2).

  9. Synthesis of Catechol Ethylether from Catechol and Ethanol Over Potasssium Loaded Active Carbon Catalyst%活性炭负载乙酸钾催化邻苯二酚和乙醇合成邻羟基苯乙醚

    Institute of Scientific and Technical Information of China (English)

    施志昆; 陈飞; 李倩; 朱天琦; 张丹凤; 方星星

    2012-01-01

    以活性碳为载体,以乙酸钾为活性组分的固体碱催化剂对邻苯二酚与乙醇气固相催化合成邻羟基苯乙醚的过程,考察了乙酸钾负载量对催化剂活性的影响以及反应条件对该反应的影响。结果表明随乙酸钾负载量的增加催化剂的碱性先增加后减小,乙酸钾负载量为15%质量分数的催化剂对该反应有最好的催化性能,当反应温度为433 K,邻苯二酚和乙醇摩尔比为10时,反应时间为150 min较适宜。在此条件下,邻苯二酚的转化率和邻羟基苯乙醚的选择性分别为99%和97%。%Synthesis of catechol ethylether by ethylation of catechol with ethanol is carried out over potassium acetate.Results show that the catalyst of 15 wt % potassium acetate loaded on active carbon exhibites the highest catalytic activity.Under the reaction conditions as follows: 433K and 1∶5 of molar ratio of ethanol to catechol,150 min of reaction time,the conversion rate of catechol and seletivity of catechol ethylether can both 99.5 % and 97.8 %.

  10. RATE AND CAPACITY OF HEPATIC MICROSOMAL RING HYDROXYLATION OF PHENOL TO HYDROQUINONE AND CATECHOL IN RAINBOW TROUT

    Science.gov (United States)

    Rainbow trout (Oncorhynchus mykiss) liver microsomes were used to study the rate of ring-hydroxylation of phenol PH) by directly measuring the production of hydroquinone (HQ), the primary metabolite, and catechol (CAT), a secondary metabolite. An HPLC method with integrated ultra...

  11. Current understanding of the interplay between catechol-O-methyltransferase genetic variants, sleep, brain development and cognitive performance in schizophrenia

    NARCIS (Netherlands)

    Tucci, Valter; Lassi, Glenda; Kas, Martien J

    2012-01-01

    Abnormal sleep is an endophenotype of schizophrenia. Here we provide an overview of the genetic mechanisms that link specific sleep physiological processes to schizophrenia-related cognitive defects. In particular, we will review the possible relationships between catechol-O-methyltransferase (COMT)

  12. Systemic catechol-O-methyl transferase inhibition enables the D1 agonist radiotracer R-[11C]SKF 82957

    DEFF Research Database (Denmark)

    Palner, Mikael; McCormick, Patrick; Parkes, Jun;

    2010-01-01

    R-[(11)C]-SKF 82957 is a high-affinity and potent dopamine D(1) receptor agonist radioligand, which gives rise to a brain-penetrant lipophilic metabolite. In this study, we demonstrate that systemic administration of catechol-O-methyl transferase (COMT) inhibitors blocks this metabolic pathway...

  13. VISCOSITY AND BINDER COMPOSITION EFFECTS ON TYROSINASE-BASED CARBON PASTE ELECTRODE FOR DETECTION OF PHENOL AND CATECHOL

    Science.gov (United States)

    The systematic study of the effect of binder viscosity on the sensitivity of a tyrosinase-based carbon paste electrode (CPE) biosensor for phenol and catechol is reported. Silicon oil binders with similar (polydimethylsiloxane) chemical composition were used to represent a wid...

  14. Activity of a Carboxyl-Terminal Truncated Form of Catechol 2,3-Dioxygenase from Planococcus sp. S5

    Directory of Open Access Journals (Sweden)

    Katarzyna Hupert-Kocurek

    2014-01-01

    Full Text Available Catechol 2,3-dioxygenases (C23Os, E.C.1.13.12.2 are two domain enzymes that catalyze degradation of monoaromatic hydrocarbons. The catalytically active C-domain of all known C23Os comprises ferrous ion ligands as well as residues forming active site pocket. The aim of this work was to examine and discuss the effect of nonsense mutation at position 289 on the activity of catechol 2,3-dioxygenase from Planococcus strain. Although the mutant C23O showed the same optimal temperature for activity as the wild-type protein (35°C, it exhibited activity slightly more tolerant to alkaline pH. Mutant enzyme exhibited also higher affinity to catechol as a substrate. Its Km (66.17 µM was approximately 30% lower than that of wild-type enzyme. Interestingly, removal of the C-terminal residues resulted in 1.5- to 1.8-fold (P<0.05 increase in the activity of C23OB61 against 4-methylcatechol and 4-chlorocatechol, respectively, while towards catechol the activity of the protein dropped to about 80% of that of the wild-type enzyme. The results obtained may facilitate the engineering of the C23O for application in the bioremediation of polluted areas.

  15. Laccase Immobilized on a PAN/Adsorbents Composite Nanofibrous Membrane for Catechol Treatment by a Biocatalysis/Adsorption Process

    Directory of Open Access Journals (Sweden)

    Qingqing Wang

    2014-03-01

    Full Text Available The treatment of catechol via biocatalysis and adsorption with a commercial laccase immobilized on polyacrylonitrile/montmorillonite/graphene oxide (PAN/MMT/GO composite nanofibers was evaluated with a homemade nanofibrous membrane reactor. The properties in this process of the immobilized laccase on PAN, PAN/MMT as well as PAN/MMT/GO with different weight ratios of MMT and GO were investigated. These membranes were successfully applied for removal of catechol from an aqueous solution. Scanning electron microscope images revealed different morphologies of the enzyme aggregates on different supports. After incorporation of MMT or MMT/GO, the optimum pH showed an alkaline shift to 4, compared to 3.5 for laccase immobilized on pure PAN nanofibers. The optimum temperature was at 55 °C for all the immobilized enzymes. Besides, the addition of GO improved the operational stability and storage stability. A 39% ± 2.23% chemical oxygen demand (COD removal from the catechol aqueous solution was achieved. Experimental results suggested that laccase, PAN, adsorbent nanoparticles (MMT/GO can be combined together for catechol treatment in industrial applications.

  16. Laccase immobilized on a PAN/adsorbents composite nanofibrous membrane for catechol treatment by a biocatalysis/adsorption process.

    Science.gov (United States)

    Wang, Qingqing; Cui, Jing; Li, Guohui; Zhang, Jinning; Li, Dawei; Huang, Fenglin; Wei, Qufu

    2014-03-19

    The treatment of catechol via biocatalysis and adsorption with a commercial laccase immobilized on polyacrylonitrile/montmorillonite/graphene oxide (PAN/MMT/GO) composite nanofibers was evaluated with a homemade nanofibrous membrane reactor. The properties in this process of the immobilized laccase on PAN, PAN/MMT as well as PAN/MMT/GO with different weight ratios of MMT and GO were investigated. These membranes were successfully applied for removal of catechol from an aqueous solution. Scanning electron microscope images revealed different morphologies of the enzyme aggregates on different supports. After incorporation of MMT or MMT/GO, the optimum pH showed an alkaline shift to 4, compared to 3.5 for laccase immobilized on pure PAN nanofibers. The optimum temperature was at 55 °C for all the immobilized enzymes. Besides, the addition of GO improved the operational stability and storage stability. A 39% ± 2.23% chemical oxygen demand (COD) removal from the catechol aqueous solution was achieved. Experimental results suggested that laccase, PAN, adsorbent nanoparticles (MMT/GO) can be combined together for catechol treatment in industrial applications.

  17. A smartphone-based colorimetric reader coupled with a remote server for rapid on-site catechols analysis.

    Science.gov (United States)

    Wang, Yun; Li, Yuanyuan; Bao, Xu; Han, Juan; Xia, Jinchen; Tian, Xiaoyu; Ni, Liang

    2016-11-01

    The search of a practical method to analyze cis-diol-containing compounds outside laboratory settings remains a substantial scientific challenge. Herein, a smartphone-based colorimetric reader was coupled with a remote server for rapid on-site analysis of catechols. A smallest-scale 2×2 colorimetric sensor array composed of pH indicators and phenylboronic acid was configured. The array was able to distinguish 13 catechols at 6 serial concentrations, through simultaneous treatment via principal component analysis, hierarchical cluster analysis, and linear discriminant analysis. After both the discriminatory power of the array and the prediction ability of the partial least squares quantitative models were proved to be predominant, the smartphone was coupled to the remote server. All the ΔRGB data were uploaded to the remote server wherein linear discriminant analysis and partial least squares processing modules were established to provide qualitative discrimination and quantitative calculation, respectively, of the analytes in real time. The applicability of this novel method to a real-life scenario was confirmed by the on-site analysis of various catechols from a water sample of the Yangtze River; the feedback result in the smartphone showed the method was able to identify the catechols with 100% accuracy and predict the concentrations to within 0.706-2.240 standard deviation.

  18. Bio-inspired catechol chemistry: a new way to develop a re-moldable and injectable coacervate hydrogel.

    Science.gov (United States)

    Oh, Yeon Jeong; Cho, Il Hwan; Lee, Haeshin; Park, Ki-Jung; Lee, Hyukjin; Park, Sung Young

    2012-12-18

    A new way is demonstrated to develop a bio-inspired coacervate hydrogel by following catechol chemistry showing injectable and re-moldable physical properties. The formed coacervate shows potential long-term stability under water. Depending on pH, formation of the coacervate has been verified which is confirmed by XPS and zeta potential measurements.

  19. Mesoporous carbon nitride based biosensor for highly sensitive and selective analysis of phenol and catechol in compost bioremediation.

    Science.gov (United States)

    Zhou, Yaoyu; Tang, Lin; Zeng, Guangming; Chen, Jun; Cai, Ye; Zhang, Yi; Yang, Guide; Liu, Yuanyuan; Zhang, Chen; Tang, Wangwang

    2014-11-15

    Herein, we reported here a promising biosensor by taking advantage of the unique ordered mesoporous carbon nitride material (MCN) to convert the recognition information into a detectable signal with enzyme firstly, which could realize the sensitive, especially, selective detection of catechol and phenol in compost bioremediation samples. The mechanism including the MCN based on electrochemical, biosensor assembly, enzyme immobilization, and enzyme kinetics (elucidating the lower detection limit, different linear range and sensitivity) was discussed in detail. Under optimal conditions, GCE/MCN/Tyr biosensor was evaluated by chronoamperometry measurements and the reduction current of phenol and catechol was proportional to their concentration in the range of 5.00 × 10(-8)-9.50 × 10(-6)M and 5.00 × 10(-8)-1.25 × 10(-5)M with a correlation coefficient of 0.9991 and 0.9881, respectively. The detection limits of catechol and phenol were 10.24 nM and 15.00 nM (S/N=3), respectively. Besides, the data obtained from interference experiments indicated that the biosensor had good specificity. All the results showed that this material is suitable for load enzyme and applied to the biosensor due to the proposed biosensor exhibited improved analytical performances in terms of the detection limit and specificity, provided a powerful tool for rapid, sensitive, especially, selective monitoring of catechol and phenol simultaneously. Moreover, the obtained results may open the way to other MCN-enzyme applications in the environmental field.

  20. Altering substrate specificity of catechol 2,3-dioxygenase from Planococcus sp. strain S5 by random mutagenesis.

    Science.gov (United States)

    Hupert-Kocurek, Katarzyna; Wojcieszyńska, Danuta; Guzik, Urszula

    2014-01-01

    c23o gene, encoding catechol 2,3-dioxygenase from Planococcus sp. strain S5 was randomly mutagenized to generate variant forms of the enzyme with higher degradation activity. Additionally, the effect of introduced mutations on the enzyme structure was analyzed based on the putative 3D models the wild-type and mutant enzymes. C23OB58 and C23OB81 mutant proteins with amino acid substitutions in close proximity to the enzyme surface or at the interface and in the vicinity of the enzyme active site respectively showed the lowest activity towards all catecholic substrates. The relative activity of C23OC61 mutant towards para-substituted catechols was 20-30% lower of the wild-type enzyme. In this mutant all changes: F191I, C268R, Y272H, V280A and Y293D were located within the conserved regions of C-terminal domain. From these F191I seems to have significant implications for enzyme activity. The highest activity towards different catechols was found for mutant C23OB65. R296Q mutation improved the activity of C23O especially against 4-chlorocatechol. The relative activity of above-mentioned mutant detected against this substrate was almost 6-fold higher than the wild-type enzyme. These results should facilitate future engineering of the enzyme for bioremediation.

  1. Cloning and mutagenesis of catechol 2,3-dioxygenase gene from the gram-positive Planococcus sp. strain S5.

    Science.gov (United States)

    Hupert-Kocurek, Katarzyna; Stawicka, Agnieszka; Wojcieszyńska, Danuta; Guzik, Urszula

    2013-01-01

    In this study, the catechol 2,3-dioxygenase gene that encodes a 307- amino-acid protein was cloned from Planococcus sp. S5. The protein was identified to be a member of the superfamily I, subfamily 2A of extradiol dioxygenases. In order to study residues and regions affecting the enzyme's catalytic parameters, the c23o gene was randomly mutated by error-prone PCR. The wild-type enzyme and mutants containing substitutions within either the C-terminal or both domains were functionally produced in Escherichia coli and their activity towards catechol was characterized. The C23OB65 mutant with R296Q substitution showed significant tolerance to acidic pH with an optimum at pH 5.0. In addition, it showed activity more than 1.5 as high as that of the wild type enzyme and its Km was 2.5 times lower. It also showed altered sensitivity to substrate inhibition. The results indicate that residue at position 296 plays a role in determining pH dependence of the enzyme and its activity. Lower activity toward catechol was shown for mutants C23OB58 and C23OB81. Despite lower activity, these mutants showed higher affinity to catechol and were more sensitive to substrate concentration than nonmutated enzyme.

  2. Antiplatelet Effect of Catechol Is Related to Inhibition of Cyclooxygenase, Reactive Oxygen Species, ERK/p38 Signaling and Thromboxane A2 Production

    Science.gov (United States)

    Wang, Tong-Mei; Lin, Bor-Ru; Yeung, Sin-Yuet; Yeh, Chien-Yang; Cheng, Ru-Hsiu; Jeng, Jiiang-Huei

    2014-01-01

    Catechol (benzenediol) is present in plant-derived products, such as vegetables, fruits, coffee, tea, wine, areca nut and cigarette smoke. Because platelet dysfunction is a risk factor of cardiovascular diseases, including stroke, atherosclerosis and myocardial infarction, the purpose of this study was to evaluate the anti-platelet and anti-inflammatory effect of catechol and its mechanisms. The effects of catechol on cyclooxygenase (COX) activity, arachidonic acid (AA)-induced aggregation, thromboxane B2 (TXB2) production, lactate dehydrogenase (LDH) release, reactive oxygen species (ROS) production and extracellular signal-regulated kinase (ERK)/p38 phosphorylation were determined in rabbit platelets. In addition, its effect on IL-1β-induced prostaglandin E2 (PGE2) production by fibroblasts was determined. The ex vivo effect of catechol on platelet aggregation was also measured. Catechol (5-25 µM) suppressed AA-induced platelet aggregation and inhibited TXB2 production at concentrations of 0.5–5 µM; however, it showed little cytotoxicity and did not alter U46619-induced platelet aggregation. Catechol (10–50 µM) suppressed COX-1 activity by 29–44% and COX-2 activity by 29–50%. It also inhibited IL-1β-induced PGE2 production, but not COX-2 expression of fibroblasts. Moreover, catechol (1–10 µM) attenuated AA-induced ROS production in platelets and phorbol myristate acetate (PMA)-induced ROS production in human polymorphonuclear leukocytes. Exposure of platelets to catechol decreased AA-induced ERK and p38 phosphorylation. Finally, intravenous administration of catechol (2.5–5 µmole/mouse) attenuated ex vivo AA-induced platelet aggregation. These results suggest that catechol exhibited anti-platelet and anti-inflammatory effects, which were mediated by inhibition of COX, ROS and TXA2 production as well as ERK/p38 phosphorylation. The anti-platelet effect of catechol was confirmed by ex vivo analysis. Exposure to catechol may affect platelet

  3. Antiplatelet effect of catechol is related to inhibition of cyclooxygenase, reactive oxygen species, ERK/p38 signaling and thromboxane A2 production.

    Directory of Open Access Journals (Sweden)

    Mei-Chi Chang

    Full Text Available Catechol (benzenediol is present in plant-derived products, such as vegetables, fruits, coffee, tea, wine, areca nut and cigarette smoke. Because platelet dysfunction is a risk factor of cardiovascular diseases, including stroke, atherosclerosis and myocardial infarction, the purpose of this study was to evaluate the anti-platelet and anti-inflammatory effect of catechol and its mechanisms. The effects of catechol on cyclooxygenase (COX activity, arachidonic acid (AA-induced aggregation, thromboxane B2 (TXB2 production, lactate dehydrogenase (LDH release, reactive oxygen species (ROS production and extracellular signal-regulated kinase (ERK/p38 phosphorylation were determined in rabbit platelets. In addition, its effect on IL-1β-induced prostaglandin E2 (PGE2 production by fibroblasts was determined. The ex vivo effect of catechol on platelet aggregation was also measured. Catechol (5-25 µM suppressed AA-induced platelet aggregation and inhibited TXB2 production at concentrations of 0.5-5 µM; however, it showed little cytotoxicity and did not alter U46619-induced platelet aggregation. Catechol (10-50 µM suppressed COX-1 activity by 29-44% and COX-2 activity by 29-50%. It also inhibited IL-1β-induced PGE2 production, but not COX-2 expression of fibroblasts. Moreover, catechol (1-10 µM attenuated AA-induced ROS production in platelets and phorbol myristate acetate (PMA-induced ROS production in human polymorphonuclear leukocytes. Exposure of platelets to catechol decreased AA-induced ERK and p38 phosphorylation. Finally, intravenous administration of catechol (2.5-5 µmole/mouse attenuated ex vivo AA-induced platelet aggregation. These results suggest that catechol exhibited anti-platelet and anti-inflammatory effects, which were mediated by inhibition of COX, ROS and TXA2 production as well as ERK/p38 phosphorylation. The anti-platelet effect of catechol was confirmed by ex vivo analysis. Exposure to catechol may affect platelet function

  4. Comparison between the removal of phenol and catechol by modified montmorillonite with two novel hydroxyl-containing Gemini surfactants

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yuening; Gao, Manglai, E-mail: mlgao@cup.edu.cn; Gu, Zheng; Luo, Zhongxin; Ye, Yage; Lu, Laifu

    2014-02-01

    Highlights: • Organo-clays were prepared by two novel hydroxyl-containing Gemini surfactants. • The kinetics and thermodynamics of the novel organo-clays were studied. • The hydroxyl group of organo-clays can increase the adsorption capacity. • BHHP-Mt was proved to be a high-efficiency adsorbent to remove phenols. - Abstract: Na-montmorillonites were modified with two novel hydroxyl-containing Gemini surfactants, 1,3-bis(hexadecyldimethylammonio)-2-hydroxypropane dichloride (BHHP) and 1,3-bis(octyldimethylammonio)-2-hydroxypropane dichloride (BOHP), via ion-exchange reaction in this study. The modified samples were characterized by X-ray diffraction (XRD) and Fourier Transform Infrared (FT-IR) spectroscopy. Phenol and catechol were removed from aqueous solution by these two kinds of organo-montmorillonites in a batch system. Important parameters have been investigated, which affect the adsorption efficiency, such as the amount of modifier, temperature, pH and contact time. The adsorption kinetics of phenol and catechol were discussed using pseudo-first-order, pseudo-second-order and intra-particle diffusion model. It indicated that the experimental data fitted very well with the pseudo-second-order kinetic model, and the equilibrium adsorption data was proved in good agreement with the Langmuir isotherm. The result also showed the adsorption capacity of catechol was higher than that of phenol in the same conditions, which might result from the extra hydroxyl in the structure of catechol. Thermodynamic quantities such as Gibbs free energy (ΔG°), the enthalpy (ΔH°), and the entropy change of sorption (ΔS°) were also determined. These parameters suggested the adsorption of phenol was a spontaneous and exothermic process, while the sorption of catechol was endothermic.

  5. Crystal structures of human 108V and 108M catechol O-methyltransferase

    Energy Technology Data Exchange (ETDEWEB)

    Rutherford, K.; Le Trong, I.; Stenkamp, R.E.; Parson, W.W. (UWASH)

    2008-08-01

    Catechol O-methyltransferase (COMT) plays important roles in the metabolism of catecholamine neurotransmitters and catechol estrogens. The development of COMT inhibitors for use in the treatment of Parkinson's disease has been aided by crystallographic structures of the rat enzyme. However, the human and rat proteins have significantly different substrate specificities. Additionally, human COMT contains a common valine-methionine polymorphism at position 108. The methionine protein is less stable than the valine polymorph, resulting in decreased enzyme activity and protein levels in vivo. Here we describe the crystal structures of the 108V and 108M variants of the soluble form of human COMT bound with S-adenosylmethionine (SAM) and a substrate analog, 3,5-dinitrocatechol. The polymorphic residue 108 is located in the {alpha}5-{beta}3 loop, buried in a hydrophobic pocket {approx}16 {angstrom} from the SAM-binding site. The 108V and 108M structures are very similar overall [RMSD of C{sup {alpha}} atoms between two structures (C{sup {alpha}} RMSD) = 0.2 {angstrom}], and the active-site residues are superposable, in accord with the observation that SAM stabilizes 108M COMT. However, the methionine side chain is packed more tightly within the polymorphic site and, consequently, interacts more closely with residues A22 ({alpha}2) and R78 ({alpha}4) than does valine. These interactions of the larger methionine result in a 0.7-{angstrom} displacement in the backbone structure near residue 108, which propagates along {alpha}1 and {alpha}5 toward the SAM-binding site. Although the overall secondary structures of the human and rat proteins are very similar (C{sup {alpha}} RMSD = 0.4 {angstrom}), several nonconserved residues are present in the SAM-(I89M, I91M, C95Y) and catechol- (C173V, R201M, E202K) binding sites. The human protein also contains three additional solvent-exposed cysteine residues (C95, C173, C188) that may contribute to intermolecular disulfide bond

  6. Emergence of hydrogen bonds from molecular dynamics simulation of substituted N-phenylthiourea-catechol oxidase complex.

    Science.gov (United States)

    Park, Kyung-Lae

    2017-01-01

    A series of N-phenylthiourea derivatives was built starting from the X-ray structure in the molecular mechanics framework and the interaction profile in the complex with the catechol oxidase was traced using molecular dynamics simulation. The results showed that the geometry and interactions between ligand and receptor were highly related to the position of the substituted side chains of phenyl moiety. At the end of molecular dynamics run, a concentrated multicenter hydrogen bond was created between the substituted ligand and receptor. The conformation of the ligand itself were also restricted in the receptor pocket. Furthermore, the simulation time of 50 ns were found to be long enough to explore the relevant conformational space and the stationary behavior of the molecular dynamic could be observed.

  7. Catechol-O-Methyltransferase gene val158met polymorphism and depressive symptoms during early childhood

    Science.gov (United States)

    Sheikh, Haroon I.; Kryski, Katie R.; Smith, Heather J.; Dougherty, Lea R.; Klein, Daniel N.; Bufferd, Sara J.; Singh, Shiva M.; Hayden, Elizabeth P.

    2017-01-01

    Catechol-O-Methyltransferase (COMT) is a critical regulator of catecholamine levels in the brain. A functional polymorphism of the COMT gene, val158met, has been linked to internalizing symptoms (i.e., depression and anxiety) in adolescents and adults. We extended this research by investigating whether the val158met polymorphism was associated with childhood symptoms of depression and anxiety in two independent samples of young children (Ns = 476 and 409). In both samples, preschool-aged children were genotyped for the COMT val158met polymorphism. Symptoms of psychopathology were assessed via parent interviews and primary caregiver reports. In both samples, children homozygous for the val allele had higher levels of depressive symptoms compared to children with at least one copy of the met allele. Our findings extend previous research in older participants by showing links between the COMT val158met polymorphism and internalizing symptoms in early childhood. PMID:23475824

  8. New Catechol Derivatives of Safrole and Their Antiproliferative Activity towards Breast Cancer Cells

    Directory of Open Access Journals (Sweden)

    Héctor Carrasco Altamirano

    2011-06-01

    Full Text Available Catechols were synthesized from safrole. Nine derivatives were prepared and assessed for antiproliferative effects using different human cell lines. The in vitro growth inhibition assay was based on the sulphorhodamine dye to quantify cell viability. The derivatives 4-allylbenzene-1,2-diol (3, 4 4-[3-(acetyloxypropyl]-1,2-phenylene diacetate (6 and 4-[3-(acetyloxypropyl]-5-nitro-1,2-phenylene diacetate (10 showed higher cytotoxicity than the parent compound 2 in tests performed on two breast cancer cell lines (MCF-7 and MDA-MB-231. The IC50 values of 40.2 ± 6.9 μM, 5.9 ± 0.8 μM and 33.8 ± 4.9 μM, respectively, were obtained without toxicity towards dermal human fibroblast (DHF cells.

  9. A model for recombination in Type II dye-sensitized solar cells: Catechol-thiophene dyes

    Science.gov (United States)

    Manzhos, Sergei; Segawa, Hiroshi; Yamashita, Koichi

    2011-03-01

    Recombination in dye-sensitized solar cells with direct injection is cast as internal conversion in the dye-Ti(OH) 2 complex. For catechol-thiophene dyes with 1, 2, or 3 thiophene units, the complex reproduces the previously observed dye-to-semiconductor bands. We compare the decomposition of the internal conversion rate by vibrational mode and predict a trend in recombination with the extension of conjugation, which offers an explanation for the trend in DSSC efficiency. We employ a simple model for the vibrational factors and show that they are only important in the presence of vibrational modes with ℏω⩽kT and strong electronic factors, as is the case here.

  10. Catechol-derivatized poly(vinyl alcohol) as a coating molecule for magnetic nanoclusters

    Energy Technology Data Exchange (ETDEWEB)

    Burnand, David [Adolphe Merkle Institute, University of Fribourg, Route de l' Ancienne Papéterie CP209, 1723 Marly 1 (Switzerland); Chemistry Department, University of Fribourg, Chemin du Musée 9, 1700 Fribourg (Switzerland); Monnier, Christophe A.; Redjem, Anthony [Adolphe Merkle Institute, University of Fribourg, Route de l' Ancienne Papéterie CP209, 1723 Marly 1 (Switzerland); Schaefer, Mark [Chemistry Department, University of Fribourg, Chemin du Musée 9, 1700 Fribourg (Switzerland); Rothen-Rutishauser, Barbara [Adolphe Merkle Institute, University of Fribourg, Route de l' Ancienne Papéterie CP209, 1723 Marly 1 (Switzerland); Kilbinger, Andreas, E-mail: andreas.kilbinger@unifr.ch [Chemistry Department, University of Fribourg, Chemin du Musée 9, 1700 Fribourg (Switzerland); Petri-Fink, Alke, E-mail: alke.fink@unifr.ch [Adolphe Merkle Institute, University of Fribourg, Route de l' Ancienne Papéterie CP209, 1723 Marly 1 (Switzerland); Chemistry Department, University of Fribourg, Chemin du Musée 9, 1700 Fribourg (Switzerland)

    2015-04-15

    Surface functionalization of superparamagnetic iron oxide nanoparticles (SPIONs) remains indispensable in promoting colloidal stability and biocompatibility. We propose a well-defined and characterized synthesis of a new catechol-functionalized RAFT (reversible addition–fragmentation chain transfer) poly(vinyl alcohol) polymer, which can be anchored onto hydrophobic SPIONs via a one-pot emulsion ligand exchange process. Both single and clustered nanoparticles are obtained and can be separated from each other. As clustered SPIONs are receiving increasing attention, this new macroligand might be of considerable interest for both basic and applied sciences. - Highlights: • We prepared well-defined polymer coated magnetic nanoparticles. • We used polyvinyl alcohol (PVA) as an alternative to commonly used plyethylene glycol (PEG). • We strongly anchored the polymer on the magnetic nanoparticles' surfaces. • We developed a one-pot emulsion ligand exchange process. • We obtained single coated particles and well defined magnetic clusters, which we successfully separated.

  11. Seawater-Assisted Self-Healing of Catechol Polymers via Hydrogen Bonding and Coordination Interactions.

    Science.gov (United States)

    Li, Jincai; Ejima, Hirotaka; Yoshie, Naoko

    2016-07-27

    It is highly desirable to prevent crack formation in polymeric materials at an early stage and to extend their lifespan, particularly when repairs to these materials would be difficult for humans. Here, we designed and synthesized catechol-functionalized polymers that can self-heal in seawater through hydrogen bonding and coordination. These bioinspired acrylate polymers are originally viscous materials, but after coordination with environmentally safe, common metal cations in seawater, namely, Ca(2+) and Mg(2+), the mechanical properties of the polymers were greatly enhanced from viscous to tough, hard materials. Reduced swelling in seawater compared with deionized water owing to the higher osmotic pressure resulted in greater toughness (∼5 MPa) and self-healing efficiencies (∼80%).

  12. A two-electron shell game: Intermediates of the extradiol-cleaving catechol dioxygenases

    Science.gov (United States)

    Fielding, Andrew J.

    2014-01-01

    Extradiol catechol ring-cleaving dioxygenases function by binding both the organic substrate and O2 at a divalent metal center in the active site. They have proven to be a particularly versatile group of enzymes with which to study the O2 activation process. Here, recent studies of homoprotocatechuate 2,3-dioxygenase (HPCD) are summarized with the objective of showing how Nature can utilize the enzyme structure and the properties of the metal and the substrate to select among many possible chemical paths to achieve both specificity and efficiency. Possible intermediates in the mechanism have been trapped by swapping active site metals, introducing active site amino acid substituted variants, and using substrates with different electron donating capacities. While each of these intermediates could form part of a viable reaction pathway, kinetic measurements significantly limit the likely candidates. Structural, kinetic, spectroscopic and computational analysis of the various intermediates shed light on how catalytic efficiency can be achieved. PMID:24615282

  13. The catechol-O-methyltransferase gene (COMT) and cognitive function from childhood through adolescence.

    Science.gov (United States)

    Gaysina, Darya; Xu, Man K; Barnett, Jennifer H; Croudace, Tim J; Wong, Andrew; Richards, Marcus; Jones, Peter B

    2013-02-01

    Genetic variation in the catechol-O-methyltransferase gene (COMT) can influence cognitive function, and this effect may depend on developmental stage. Using a large representative British birth cohort, we investigated the effect of COMT on cognitive function (verbal and non-verbal) at ages 8 and 15 years taking into account the possible modifying effect of pubertal stage. Five functional COMT polymorphisms, rs6269, rs4818, rs4680, rs737865 and rs165599 were analysed. Associations between COMT polymorphisms and cognition were tested using regression and latent variable structural equation modelling (SEM). Before correction for multiple testing, COMT rs737865 showed association with reading comprehension, verbal ability and global cognition at age 15 years in pubescent boys only. Although there was some evidence for age- and sex-specific effects of the COMT rs737865 none remained significant after correction for multiple testing. Further studies are necessary in order to make firmer conclusions.

  14. New catechol derivatives of safrole and their antiproliferative activity towards breast cancer cells.

    Science.gov (United States)

    Madrid Villegas, Alejandro; Espinoza Catalán, Luis; Montenegro Venegas, Iván; Villena García, Joan; Carrasco Altamirano, Héctor

    2011-06-03

    Catechols were synthesized from safrole. Nine derivatives were prepared and assessed for antiproliferative effects using different human cell lines. The in vitro growth inhibition assay was based on the sulphorhodamine dye to quantify cell viability. The derivatives 4-allylbenzene-1,2-diol (3), 4 4-[3-(acetyloxy)propyl]-1,2-phenylene diacetate (6) and 4-[3-(acetyloxy)propyl]-5-nitro-1,2-phenylene diacetate (10) showed higher cytotoxicity than the parent compound 2 in tests performed on two breast cancer cell lines (MCF-7 and MDA-MB-231). The IC₅₀ values of 40.2 ± 6.9 μM, 5.9 ± 0.8 μM and 33.8 ± 4.9 μM, respectively, were obtained without toxicity towards dermal human fibroblast (DHF cells).

  15. Energy level alignment of catechol molecular orbitals on ZnO(1 1 2-bar 0) and TiO{sub 2}(1 1 0) surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Rangan, Sylvie, E-mail: rangan@physics.rutgers.edu [Department of Physics and Astronomy and Laboratory for Surface Modification, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Theisen, Jean-Patrick; Bersch, Eric; Bartynski, R.A. [Department of Physics and Astronomy and Laboratory for Surface Modification, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States)

    2010-05-15

    The occupied and unoccupied electronic structure of catechol adsorbed onto two single crystal surfaces, rutile TiO{sub 2}(1 1 0) and wurtzite ZnO(1 1 2-bar 0), have been investigated using UV-photoemission and inverse photoemission spectroscopies (UPS and IPS) in an ultra-high vacuum environment. To aid in assignment of the spectral features, model metal-bound catechol structures were calculated using a DFT approach. From these measurements, the energy alignment of the catechol-related states with respect to the substrates band edges is directly determined and is in good agreement with a direct injection process of the photoexcited electron into the substrate conduction band, resulting in the characteristic absorption properties of adsorbed catechol.

  16. Energy level alignment of catechol molecular orbitals on ZnO(1 1 2¯ 0) and TiO 2(1 1 0) surfaces

    Science.gov (United States)

    Rangan, Sylvie; Theisen, Jean-Patrick; Bersch, Eric; Bartynski, R. A.

    2010-05-01

    The occupied and unoccupied electronic structure of catechol adsorbed onto two single crystal surfaces, rutile TiO 2(1 1 0) and wurtzite ZnO(1 1 2¯ 0), have been investigated using UV-photoemission and inverse photoemission spectroscopies (UPS and IPS) in an ultra-high vacuum environment. To aid in assignment of the spectral features, model metal-bound catechol structures were calculated using a DFT approach. From these measurements, the energy alignment of the catechol-related states with respect to the substrates band edges is directly determined and is in good agreement with a direct injection process of the photoexcited electron into the substrate conduction band, resulting in the characteristic absorption properties of adsorbed catechol.

  17. Low enzymatic activity haplotypes of the human catechol-O-methyltransferase gene: enrichment for marker SNPs.

    Directory of Open Access Journals (Sweden)

    Andrea G Nackley

    Full Text Available Catechol-O-methyltransferase (COMT is an enzyme that plays a key role in the modulation of catechol-dependent functions such as cognition, cardiovascular function, and pain processing. Three common haplotypes of the human COMT gene, divergent in two synonymous and one nonsynonymous (val(158met position, designated as low (LPS, average (APS, and high pain sensitive (HPS, are associated with experimental pain sensitivity and risk of developing chronic musculoskeletal pain conditions. APS and HPS haplotypes produce significant functional effects, coding for 3- and 20-fold reductions in COMT enzymatic activity, respectively. In the present study, we investigated whether additional minor single nucleotide polymorphisms (SNPs, accruing in 1 to 5% of the population, situated in the COMT transcript region contribute to haplotype-dependent enzymatic activity. Computer analysis of COMT ESTs showed that one synonymous minor SNP (rs769224 is linked to the APS haplotype and three minor SNPs (two synonymous: rs6267, rs740602 and one nonsynonymous: rs8192488 are linked to the HPS haplotype. Results from in silico and in vitro experiments revealed that inclusion of allelic variants of these minor SNPs in APS or HPS haplotypes did not modify COMT function at the level of mRNA folding, RNA transcription, protein translation, or enzymatic activity. These data suggest that neutral variants are carried with APS and HPS haplotypes, while the high activity LPS haplotype displays less linked variation. Thus, both minor synonymous and nonsynonymous SNPs in the coding region are markers of functional APS and HPS haplotypes rather than independent contributors to COMT activity.

  18. The Role of Human Aldo-Keto Reductases in the Metabolic Activation and Detoxication of Polycyclic Aromatic Hydrocarbons: Interconversion of PAH Catechols and PAH o-Quinones

    OpenAIRE

    Li eZhang; Yi eJin; Meng eHuang; Penning, Trevor M.

    2012-01-01

    Polycyclic aromatic hydrocarbons (PAH) are ubiquitous environmental pollutants. They are procarcinogens requiring metabolic activation to elicit their deleterious effects. Aldo-keto reductases (AKR) catalyze the oxidation of proximate carcinogenic PAH trans-dihydrodiols to yield electrophilic and redox-active PAH o-quinones. AKRs are also found to be capable of reducing PAH o-quinones to form PAH catechols. The interconversion of o-quinones and catechols results in the redox-cycling of PAH o-...

  19. New route to the mixed valence semiquinone-catecholate based mononuclear FeIII and catecholate based dinuclear MnIII complexes: first experimental evidence of valence tautomerism in an iron complex.

    Science.gov (United States)

    Shaikh, Nizamuddin; Goswami, Sanchita; Panja, Anangamohan; Wang, Xin-Yi; Gao, Song; Butcher, Ray J; Banerjee, Pradyot

    2004-09-20

    The semiquinone-catecholate based mixed valence complex, [FeIII(bispicen)(Cl4Cat)(Cl4SQ)] x DMF (1), and catecholate based (H2bispictn)[Mn2III(Cl4Cat)4(DMF)2] (2) (bispicen = N,N'-bis(2-pyridylmethyl)-1,2-ethanediamine, bispictn = N,N'-bis(2-pyridylmethyl)-1,3-propanediamine, Cl4Cat = tetrachlorocatecholate dianion, and Cl4SQ = tetrachlorosemiquinone radical anion) were synthesized directly utilizing a facile route. Both the complexes have been characterized by single crystal X-ray diffraction study. The electronic structures have been elucidated by UV-vis-NIR absorption spectroscopy, cyclic voltammetry, EPR, and magnetic properties. The structural as well as spectroscopic features support the mixed valence tetrachlorosemiquinone-tetrachlorocatecholate charge distribution in 1. The ligand based mixed valence state was further confirmed by the presence of an intervalence charge transfer (IVCT) band in the 1900 nm region both in solution and in the solid. The intramolecular electron transfer, a phenomenon known as valence tautomerism (VT), has been followed by electronic absorption spectroscopy. For 1, the isomeric form [FeIII(bispicen)(Cl4Cat)(Cl4SQ)] is favored at low temperature, while at an elevated temperature, the [FeII(bispicen)(Cl4SQ)2] redox isomer dominates. Infrared as well as UV-vis-NIR spectral characterization for 2 suggest that the MnIII(Cat)2- moiety is admixed with its mixed valence semiquinone-catecholate isomer MnII(SQ)(Cat)-, and the electronic absorption spectrum is dominated by the mixed charged species. The origin of the intervalence charge transfer band in the 1900 nm range is associated with the mixed valence form, MnII(Cl4Cat)(Cl4SQ)-. The observation of VT in complex 1 is the first example where a mixed valence semiquinone-catecholate iron(III) complex undergoes intramolecular electron transfer similar to manganese and cobalt complexes.

  20. Suppression of electrochemical decomposition of propylene carbonate (PC) on a graphite anode in PC base electrolyte with catechol carbonate; Catechol carbonate tenka denkaieki deno graphite fukyokujo ni okeru propylene carbonate no bunseki yokusei

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Congxiao; Nakamura, H. [Saga Univ. (Japan). Faculty of Science and Engineering; Noguchi, H.; Yoshio, M.; Yoshitake, H. [Ube Industries Ltd. (Japan)

    1998-03-05

    In this study, 0.5-2.0 wt.% of catechol carbonates were added to a 1MLiPF6/propylene carbonate (PC) - diethyl carbonate (DEC) electrolyte, and this addition could suppress the decomposition of PC on MCMB6-28 (graphitized meso-phase carbon manufactured by the Osaka, Gas Co., Ltd.). The catechol carbonate-added electrolyte proved effective in suppressing the decomposition of PC even on graphite, such as NG-7 (manufactured by the Kansai Netsu Kagaku Co, Ltd.), natural graphite produced in China and natural graphite produced in Madagascar. It is highly possible that catechol carbonates act as radical scavengers. It could be ascertained that, when this electrolyte was used for a LiCoO2/MCMB6-28 lithium ion secondary battery, the capacity was substantially the same as the calculated one, and a PC-based electrolyte can be used for a lithium ion secondary battery using a negative electrode of graphite. 13 refs., 10 figs., 2 tabs.

  1. A novel amperometric catechol biosensor based on α-Fe2O3 nanocrystals-modified carbon paste electrode.

    Science.gov (United States)

    Sarika, C; Shivakumar, M S; Shivakumara, C; Krishnamurthy, G; Narasimha Murthy, B; Lekshmi, I C

    2017-05-01

    In this work, we designed an amperometric catechol biosensor based on α-Fe2O3 nanocrystals (NCs) incorporated carbon-paste electrode. Laccase enzyme is then assembled onto the modified electrode surface to form a nanobiocomposite enhancing the electron transfer reactions at the enzyme's active metal centers for catechol oxidation. The biosensor gave good sensitivity with a linear detection response in the range of 8-800 μM with limit of detection 4.28 μM. We successfully employed the sensor for real water sample analysis. The results illustrate that the metal oxide NCs have enormous potential in the construction of biosensors for sensitive determination of phenol derivatives.

  2. Enhancement of fill factor in air-processed inverted organic solar cells using self-assembled monolayer of fullerene catechol

    Science.gov (United States)

    Jeon, Il; Ogumi, Keisuke; Nakagawa, Takafumi; Matsuo, Yutaka

    2016-08-01

    [60]Fullerene catechol self-assembled monolayers were prepared and applied to inverted organic solar cells by an immersion method, and their energy conversion properties were measured. By introducing fullerenes at the surface, we improved the hole-blocking capability of electron-transporting metal oxide, as shown by the fill factor enhancement. The fullerene catechol-treated TiO x -containing device gave a power conversion efficiency (PCE) of 2.81% with a fill factor of 0.56 while the non treated device gave a PCE of 2.46% with a fill factor of 0.49. The solar cell efficiency improved by 13% compared with the non treated reference device.

  3. Electrocatalytic oxidation of dihydronicotineamide adenine dinucleotide on gold electrode modified with catechol-terminated alkanethiol self-assembly

    Energy Technology Data Exchange (ETDEWEB)

    Nakano, Koji [Department of Applied Chemistry, Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan)], E-mail: kojitcm@mbox.nc.kyushu-u.ac.jp; Ohkubo, Kimihiko; Taira, Hiroaki [Department of Applied Chemistry, Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Takagi, Makoto [Fukuoka Women' s University, 1-1-1, Kasumigaoka, Higashi-ku, Fukuoka 813-8529 (Japan); Imato, Toshihiko [Department of Applied Chemistry, Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan)

    2008-06-30

    Synthesis of a mercaptoundecaneamide derivative having a terminus of catechol is described. FT-IR spectroscopic characterization showed that the new molecular entry simply undergoes molecular self-assembly on Au substrate surfaces promoting intra- and intermolecular hydrogen bonds to form well-packed monolayers. Cyclic voltammetric (CV) measurements on the monolayer-modified Au electrode revealed that the surface adlayer possesses specific electrochemical activity due to the reversible catechol/o-quinone redox reaction having characteristics of a surface process and also pH-dependence in its formal potential (59 mV per pH). Detailed analysis of CVs gave fundamental electrochemical parameters including the electroactive surface coverage (0.20-0.24 nmol cm{sup -2}), the transfer coefficients (0.24 in oxidation and 0.81 in reduction), and also the electron transfer rate constant (1.10-2.76 s{sup -1}). These data were almost consistent to those seen in literature. We have also found that the catechol monolayer modified electrode exhibits an electrocatalytic function in NADH oxidation. That is, the faradaic current appeared reinforcingly at around the same potential where catechol function is oxidized in the monolayer and increased with an increase in the NADH concentration from 1 to 5 mM, and then reached to a plateau indicating a catalyzed reaction pathway. Detailed analyses revealed that the present system could be characterized by its weak stability of the intermediate compound formed and prompt reaction rate compared with the previously reported chemically modified electrode (CME) systems. We think this type of achievement should be important for the basics of biosensors that rely on dehydrogenase enzymes.

  4. In Situ Synthesis of Antimicrobial Silver Nanoparticles within Antifouling Zwitterionic Hydrogels by Catecholic Redox Chemistry for Wound Healing Application.

    Science.gov (United States)

    GhavamiNejad, Amin; Park, Chan Hee; Kim, Cheol Sang

    2016-03-14

    A multifunctional hydrogel that combines the dual functionality of both antifouling and antimicrobial capacities holds great potential for many bioapplications. Many approaches and different materials have been employed to synthesize such a material. However, a systematic study, including in vitro and in vivo evaluation, on such a material as wound dressings is highly scarce at present. Herein, we report on a new strategy that uses catecholic chemistry to synthesize antimicrobial silver nanoparticles impregnated into antifouling zwitterionic hydrogels. For this purpose, hydrophobic dopamine methacrylamide monomer (DMA) was mixed in an aqueous solution of sodium tetraborate decahydrate and DMA monomer became soluble after increasing pH to 9 due to the complexation between catechol groups and boron. Then, cross-linking polymerization of zwitterionic monomer was carried out with the solution of the protected dopamine monomer to produce a new hydrogel. When this new hydrogel comes in contact with a silver nitrate solution, silver nanoparticles (AgNPs) are formed in its structure as a result of the redox property of the catechol groups and in the absence of any other external reducing agent. The results obtained from TEM and XRD measurements indicate that AgNPs with diameters of around 20 nm had formed within the networks. FESEM images confirmed that the silver nanoparticles were homogeneously incorporated throughout the hydrogel network, and FTIR spectroscopy demonstrated that the catechol moiety in the polymeric backbone of the hydrogel is responsible for the reduction of silver ions into the AgNPs. Finally, the in vitro and in vivo experiments suggest that these mussel-inspired, antifouling, antibacterial hydrogels have great potential for use in wound healing applications.

  5. A highly sensitive electrochemical biosensor for catechol using conducting polymer reduced graphene oxide-metal oxide enzyme modified electrode.

    Science.gov (United States)

    Sethuraman, V; Muthuraja, P; Anandha Raj, J; Manisankar, P

    2016-10-15

    The fabrication, characterization and analytical performances were investigated for a catechol biosensor, based on the PEDOT-rGO-Fe2O3-PPO composite modified glassy carbon (GC) electrode. The graphene oxide (GO) doped conducting polymer poly (3,4-ethylenedioxythiophene) (PEDOT) was prepared through electrochemical polymerization by potential cycling. Reduction of PEDOT-GO was carried out by amperometric method. Fe2O3 nanoparticles were synthesized in ethanol by hydrothermal method. The mixture of Fe2O3, PPO and glutaraldehyde was casted on the PEDOT-rGO electrode. The surface morphology of the modified electrodes was studied by FE-SEM and AFM. Cyclic voltammetric studies of catechol on the enzyme modified electrode revealed higher reduction peak current. Determination of catechol was carried out successfully by Differential Pulse Voltammetry (DPV) technique. The fabricated biosensor investigated shows a maximum current response at pH 6.5. The catechol biosensor exhibited wide sensing linear range from 4×10(-8) to 6.20×10(-5)M, lower detection limit of 7×10(-9)M, current maxima (Imax) of 92.55µA and Michaelis-Menten (Km) constant of 30.48µM. The activation energy (Ea) of enzyme electrode is 35.93KJmol(-1) at 50°C. There is no interference from d-glucose and l-glutamic acid, ascorbic acid and o-nitrophenol. The PEDOT-rGO-Fe2O3-PPO biosensor was stable for at least 75 days when stored in a buffer at about 4°C.

  6. Construction of mussel-inspired coating via the direct reaction of catechol and polyethyleneimine for efficient heparin immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yujie [School of Material Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); The Institute of Biomaterials and Surface Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Luo, Rifang, E-mail: lrifang@126.com [School of Material Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); The Institute of Biomaterials and Surface Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Shen, Fangyu; Tang, Linlin [School of Material Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); The Institute of Biomaterials and Surface Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Wang, Jin, E-mail: jinxxwang@263.net [School of Material Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); The Institute of Biomaterials and Surface Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Huang, Nan [School of Material Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); The Institute of Biomaterials and Surface Engineering, Southwest Jiaotong University, Chengdu 610031 (China)

    2015-02-15

    Highlights: • Catechol (CA) and PEI copolymerization was a mimetic and dopamine-like coating method. • CA/PEI film provided amine groups and was effective in heparin immobilization. • CA/PEI coating could inhibit smooth muscle cell proliferation. • CA/PEI coating did not show any significant cytotoxicity to endothelial cell. - Abstract: Dopamine could self-polymerize to form the coating on various substrates and the co-existence of catechols and amines was crucial in performing such polymerization process. In this work, a mimetic approach of coating formation was carried out based on the co-polymerization of catechol (CA) and polyethyleneimine (PEI). Mussel-inspired CA/PEI coating was deposited on 316L stainless steel (SS). Fourier transform infrared spectra (FTIR) and X-ray photoelectron spectroscopy (XPS) demonstrated the successful coating formation. QCM measurement showed good affinity of heparin immobilization on CA/PEI coating surface ascribed to the amine groups. Herein, vascular cell-material interactions like endothelial cells (ECs) and smooth muscle cells (SMCs) were also investigated. Interestingly, CA/PEI and heparin modified coatings presented no cytotoxicity to ECs, however to a certain extent, decreased SMCs proliferation. Moreover, heparin-binding surface presented significant anti-platelet adhesion and activation properties. These results effectively suggested that the mussel-inspired CA/PEI coating might be promising when served as a platform for biomolecule immobilization.

  7. Hydroxyapatite-based sorbents: elaboration, characterization and application for the removal of catechol from the aqueous phase.

    Science.gov (United States)

    Sebei, Haroun; Minh, Doan Pham; Lyczko, Nathalie; Sharrock, Patrick; Nzihou, Ange

    2016-12-26

    Hydroxyapatite (HAP) is highly considered as good sorbent for the removal of metals from the aqueous phase. However, soluble metals co-exist with organic pollutants in wastewaters. But little work has been devoted to investigate the reactivity of HAP for the removal of organic compounds. The main objective of this work is to study the reactivity of HAP-based sorbents for the removal of catechol as a model organic pollutant from an aqueous solution. Thus, HAP sorbents were firstly synthesized using calcium carbonate and potassium dihydrogen phosphate under moderate conditions (25-80°C, atmospheric pressure). A zinc-doped HAP was also used as sorbent, which was obtained from the contact of HAP with an aqueous solution of zinc nitrate. All the sorbents were characterized by different standard physico-chemical techniques. The sorption of catechol was carried out in a batch reactor under stirring at room temperature and pressure. Zinc-doped HAP sorbent was found to be more reactive than non-doped HAP sorbents for the fixation of catechol. The highest sorption capacity was of 15 mg of C per gram of zinc-doped HAP sorbent. The results obtained suggest the reaction scheme of HAP sorbents with metals and organic pollutants when HAP sorbents were used for the treatment of complex wastewaters.

  8. An Optical Biosensor based on Immobilization of Laccase and MBTH in Stacked Films for the Detection of Catechol.

    Directory of Open Access Journals (Sweden)

    Hamidah Sidek

    2007-10-01

    Full Text Available The fabrication of an optical biosensor by using stacked films where 3-methyl-2-benzothiazolinone hydrazone (MBTH was immobilized in a hybrid nafion/sol-gelsilicate film and laccase in a chitosan film for the detection of phenolic compounds wasdescribed. Quinone and/or phenoxy radical product from the enzymatic oxidation ofphenolic compounds was allowed to couple with MBTH to form a colored azo-dye productfor spectrophometric detection. The biosensor demonstrated a linear response to catecholconcentration range of 0.5-8.0 mM with detection limit of 0.33 mM and response time of10 min. The reproducibility of the fabricated biosensor was good with RSD value of 5.3 %(n = 8 and stable for at least 2 months. The use of the hybrid materials of nafion/sol-gelsilicate to immobilize laccase has altered the selectivity of the enzyme to various phenoliccompounds such as catechol, guaicol, o-cresol and m-cresol when compared to the non-immobilized enzyme. When immobilized in this hybrid film, the biosensor response onlyto catechol and not other phenolic compounds investigated. Immobilization in this hybridmaterial has enable the biosensor to be more selective to catechol compared with the non-immobilized enzyme. This shows that by a careful selection of different immobilizationmatrices, the selectivity of an enzyme can be modified to yield a biosensor with goodselectivity towards certain targeted analytes.

  9. Amperometric catechol biosensor based on laccase immobilized on nitrogen-doped ordered mesoporous carbon (N-OMC)/PVA matrix

    Science.gov (United States)

    Guo, Meiqing; Wang, Hefeng; Huang, Di; Han, Zhijun; Li, Qiang; Wang, Xiaojun; Chen, Jing

    2014-06-01

    A functionalized nitrogen-containing ordered mesoporous carbon (N-OMC), which shows good electrical properties, was synthesized by the carbonization of polyaniline inside a SBA-15 mesoporous silica template. Based on this, through entrapping laccase onto the N-OMC/polyvinyl alcohol (PVA) film a facilely fabricated amperometric biosensor was developed. Laccase from Trametes versicolor was assembled on a composite film of a N-OMC/PVA modified Au electrode and the electrochemical behavior was investigated. The results indicated that the N-OMC modified electrode exhibits electrical properties towards catechol. The optimum experimental conditions of a biosensor for the detection of catechol were studied in detail. Under the optimal conditions, the sensitivity of the biosensor was 0.29 A*M-1 with a detection limit of 0.31 μM and a linear detection range from 0.39 μM to 8.98 μM for catechol. The calibration curve followed the Michaelis-Menten kinetics and the apparent Michaelis-Menten \\left( K_{M}^{app} \\right) was 6.28 μM. This work demonstrated that the N-OMC/PVA composite provides a suitable support for laccase immobilization and the construction of a biosensor.

  10. Application of a Novel Semiconductor Catalyst, CT, in Degradation of Aromatic Pollutants in Wastewater: Phenol and Catechol

    Directory of Open Access Journals (Sweden)

    Xiao Chen

    2014-01-01

    Full Text Available Water-soluble phenol and phenolic compounds were generally removed via advanced oxidation processes. A novel semiconductor catalyst, CT, was the first-time employed in the present study to degrade phenol and catechol. The phenolic compounds (initial concentration of 88 mg L−1 were completely mineralized by the CT catalytic nanoparticles (1% within 15 days, under acidic condition and with the presence of mild UV radiation (15 w, the emitted wavelength is 254 nm and the light intensity <26 μw/cm2. Under the same reaction condition, 1% TiO2 (mixture of rutile and anatase, nanopowder, <100 nm and H2O2 had lower removal efficiency (phenol: <42%; catechol: <60%, whereas the control (without addition of catalysts/H2O2 only showed <12% removal. The processes of phenol/catechol removal by CT followed pseudo-zero-order kinetics. The aromatic structures absorbed the UV energy and passed to an excited state, which the CT worked on. The pollutants were adsorbed on the CT’s surface and oxidized via charge-transfer and hydroxyl radical generation by CT. Given low initial concentrations, a circumstance encountered in wastewater polishing, the current set-up should be an efficient and less energy- and chemical-consumptive treatment method.

  11. Browning inhibition mechanisms by cysteine, ascorbic acid and citric acid, and identifying PPO-catechol-cysteine reaction products.

    Science.gov (United States)

    Ali, Hussein M; El-Gizawy, Ahmed M; El-Bassiouny, Rawia E I; Saleh, Mahmoud A

    2015-06-01

    The titled compounds were examined as PPO inhibitors and antibrowning agents; their various mechanisms were investigated and discussed. All compounds reduced significantly both the browning process and PPO activity. Browning index gave strong correlation with PPO activity (r(2) = 0.96, n = 19) indicating that the browning process is mainly enzymatic. Ascorbic acid could reduce the formed quinone instantly to the original substrate (catechol) at high concentration (>1.5 %) while at lower concentrations acted as competitive inhibitor (KI = 0.256 ± 0.067 mM). Cysteine, at higher concentrations (≥1.0 %), reacted with the resulted quinone to give a colorless products while at the low concentrations, cysteine worked as competitive inhibitor (KI = 1.113 ± 0.176 mM). Citric acid acted only as PPO non-competitive inhibitor with KI = 2.074 ± 0.363 mM. The products of PPO-catechole-cysteine reaction could be separation and identification by LC-ESI-MS. Results indicated that the product of the enzymatic oxidation of catechol, quinone, undergoes two successive nucleophilic attacks by cysteine thiol group. Cysteine was condensed with the resulted mono and dithiocatechols to form peptide side chains.

  12. Syntheses, characterization, and anti-cancer activities of pyridine-amide based compounds containing appended phenol or catechol groups

    Indian Academy of Sciences (India)

    Afsar Ali; Deepak Bansal; Nagendra K Kaushik; Neha Kaushik; Neha Kaushik; Eun Ha Choi; Rajeev Gupta

    2014-07-01

    Several pyridine-amide compounds appended with phenol/catechol groups are synthesized. These compounds consist of protected or deprotected phenol/catechol groups and offer pyridine, amide, and phenol/catechol functional groups. All compounds have been well-characterized by various spectroscopic methods, elemental analysis, thermal studies, and crystallography. The biological activities of all compounds were investigated while a few compounds significantly decreased the metabolic viability, growth and clonogenicity of T98G cells in dose dependent manner. Accumulation of ROS was observed in T98G cells, which displayed a compromised redox status as evident from increased cellular Caspase 3/7 activity and formation of micronuclei. The in silico pharmacokinetic studies suggest that all compounds have good bioavailability, water solubility and other drug-like parameters. A few compounds were identified as the lead molecules for future investigation due to their: (a) high activity against T98G brain, H-460 lung, and SNU-80 thyroid cancer cells; (b) low cytotoxicity in non-malignant HEK and MRC-5 cells; (c) low toxic risks based on in silico evaluation; (d) good theoretical oral bioavailability according to Lipinski ‘rule of five’ pharmacokinetic parameters; and (e) better drug-likeness and drug-score values.

  13. Optical Absorption Spectra and Excitons of Dye-Substrate Interfaces: Catechol on TiO2(110).

    Science.gov (United States)

    Mowbray, Duncan John; Migani, Annapaola

    2016-06-14

    Optimizing the photovoltaic efficiency of dye-sensitized solar cells (DSSC) based on staggered gap heterojunctions requires a detailed understanding of sub-band gap transitions in the visible from the dye directly to the substrate's conduction band (CB) (type-II DSSCs). Here, we calculate the optical absorption spectra and spatial distribution of bright excitons in the visible region for a prototypical DSSC, catechol on rutile TiO2(110), as a function of coverage and deprotonation of the OH anchoring groups. This is accomplished by solving the Bethe-Salpeter equation (BSE) based on hybrid range-separated exchange and correlation functional (HSE06) density functional theory (DFT) calculations. Such a treatment is necessary to accurately describe the interfacial level alignment and the weakly bound charge transfer transitions that are the dominant absorption mechanism in type-II DSSCs. Our HSE06 BSE spectra agree semiquantitatively with spectra measured for catechol on anatase TiO2 nanoparticles. Our results suggest deprotonation of catechol's OH anchoring groups, while being nearly isoenergetic at high coverages, shifts the onset of the absorption spectra to lower energies, with a concomitant increase in photovoltaic efficiency. Further, the most relevant bright excitons in the visible region are rather intense charge transfer transitions with the electron and hole spatially separated in both the [110] and [001] directions. Such detailed information on the absorption spectra and excitons is only accessible via periodic models of the combined dye-substrate interface.

  14. Diazonium modification of porous graphitic carbon with catechol and amide groups for hydrophilic interaction and attenuated reversed phase liquid chromatography.

    Science.gov (United States)

    Iverson, Chad D; Zhang, Ya; Lucy, Charles A

    2015-11-27

    Porous graphitic carbon (PGC) is an increasingly popular and attractive phase for HPLC on account of its chemical and thermal stability, and its unique separation mechanism. However, native PGC is strongly hydrophobic and in some instances excessively retentive. As part of our effort to build a library of hydrophilic covalently modified PGC phases, we functionalized PGC with catechol and amide groups by means of aryl diazonium chemistry to produce two new phases. Successful grafting was confirmed by X-ray photoelectron spectroscopy (XPS). Under HILIC conditions, the Catechol-PGC showed up to 5-fold increased retention relative to unmodified PGC and selectivity that differed from four other HILIC phases. Under reversed phase conditions, the Amide-PGC reduced the retentivity of PGC by almost 90%. The chromatographic performance of Catechol-PGC and Amide-PGC is demonstrated by separations of nucleobases, nucleosides, phenols, alkaline pharmaceuticals, and performance enhancing stimulants. These compounds had retention factors (k) ranging from 0.5 to 13.

  15. Polycyclic aromatic hydrocarbons from the pyrolysis of catechol (ortho-dihydroxybenzene), a model fuel representative of entities in tobacco, coal, and lignin

    Energy Technology Data Exchange (ETDEWEB)

    Wornat, M.J.; Ledesma, E.B.; Marsh, N.D. [Princeton University, Princeton, NJ (United States). Dept. of Mechanical and Aerospace Engineering

    2001-10-09

    In order to better understand the formation of polycyclic aromatic hydrocarbons (PAH) from complex fuels, we have performed pyrolysis experiments in a laminar-flow reactor, using the model fuel catechol (Ortho-dihydroxybenzene), a phenol-type compound representative of structural entities in tobacco, coal and wood. Employing high pressure liquid chromatography with diode-array ultraviolet-visible (UV) detection, we have unequivocally identified 59 individual species among the condensed-phase products of catechol pyrolysis at a temperature of 1000{degree}C and a residence time of 0.4 s. Also identified are two oxygen-containing compounds that are produced only at pyrolysis temperatures lower than 900{degree}C. Of the total 61 species, fifty have never before been identified as pyrolysis products of any pure phenol type compound. Two of the catechol pyrolysis products, 5-ethynylacenaphthylene and 3-ethynylphenanthrene, have never before been identified as products of any fuel. Ranging in size from one to eight fused aromatic rings, the catechol pyrolysis products comprise several compound classes: bi-aryls, indene benzologues, benzenoid PAH, alkylated aromatics, fluoranthene benzologues, cyclopenta-fused PAH, ethynyl-substituted aromatics, polyacetylenes, and oxygen-containing aromatics. The catechol pyrolysis products bear remarkable compositional similarity to the products of bituminous coal volatiles pyrolyzed at the same temperature - demonstrating the relevance of these catechol model compound experiments to the study of complex fuels such as coal, wood and tobacco. The UV spectra, establishing compound identity, are presented for several of the identified catechol product components. 70 refs., 13 figs., 6 tabs.

  16. Organic impurity profiling of methylone and intermediate compounds synthesized from catechol.

    Science.gov (United States)

    Heather, Erin; Bortz, Adam; Shimmon, Ronald; McDonagh, Andrew M

    2016-11-25

    This work examined the synthesis and organic impurity profile of methylone prepared from catechol. The primary aim of this work was to determine whether the synthetic pathway used to prepare 3,4-methylenedioxypropiophenone could be ascertained through analysis of the synthesized methylone. The secondary aim was the structural elucidation and origin determination of the organic impurities detected in methylone and the intermediate compounds. The organic impurities present in the reaction products were identified using GC-MS and NMR spectroscopy. Six organic impurities were detected in 1,3-benzodioxole and identified as the 1,3-benzodioxole dimer, 1,3-benzodioxole trimer, [1,3] dioxolo[4,5-b]oxanthrene, 4,4'-, 4,5'-, and 5,5'-methylenebis-1,3-benzodioxole. Six organic impurities were detected in 3,4-methylenedioxypropiophenone and identified as (2-hydroxyphenyl) propanoate, [2-(chloromethoxy) phenyl] propanoate, (2-propanoyloxyphenyl)propanoate, 5-[1-(1,3-benzodioxol-5-yl)prop-1-enyl]-1,3-benzodioxole, (5E)- and (5Z)-7-(1,3-benzodioxol-5-yl)-5-ethylidene-6-methyl-cyclopenta[f][1,3]benzodioxole). Exploratory synthetic experiments were also conducted to unambiguously identify the organic impurities detected in 3,4-methylenedioxypropiophenone. Two organic impurities were detected in 5-bromo-3,4-methylenedioxypropiophenone and identified as [2-(chloromethoxy)phenyl] propanoate and 3,4-methylenedioxypropiophenone. Five organic impurities were detected in methylone and identified as 3,4-methylenedioxypropiophenone, 1-(1,3-benzodioxol-5-yl)-N-methyl-propan-1-imine, 1-(1,3-benzodioxol-5-yl)-2-methylimino-propan-1-one, 1-(1,3-benzodioxol-5-yl)-N1,N2-dimethyl-propane-1,2-diimine and butylated hydroxytoluene. The origin of these organic impurities was also ascertained, providing valuable insight into the chemical profiles of methylone and the intermediate compounds. However, neither the catechol precursor nor the 1,3-benzodioxole intermediate could be identified based on the

  17. STUDY ON THE COPOLYMERIC COATING OF TERPENE-CATECHOL WITH RAW LACQUER(Ⅰ)--Synthesis of terpene-catechol functional resin and its separation from terpene resin%萜烯邻苯二酚树脂-生漆共聚涂料研究(Ⅰ)--萜烯-邻苯二酚功能基树脂的分离提纯

    Institute of Scientific and Technical Information of China (English)

    雷福厚; 蓝虹云; 姚兴东; 蒙晓波; 安鑫南

    2005-01-01

    以萜烯树脂和邻苯二酚为原料,合成了萜烯-邻苯二酚树脂.采用柱层析法分离萜烯树脂和萜烯-邻苯二酚树脂,分别采用中性氧化铝和强碱性阴离子交换树脂作固定相,汽油、乙醇、NaOH-乙醇溶液作洗脱剂对萜烯树脂和萜烯-邻苯二酚树脂进行分离提纯.通过对洗脱液进行紫外光谱分析,表明用中性氧化铝作固定相,分别用汽油、乙醇和NaOH-乙醇溶液洗脱,能较好地分离萜烯树脂和萜烯-邻苯二酚树脂.%Synthesis of terpene-catechol resin from terpene resin and catechol was reported in this paper.Results showed that terpene-catechol resin could be synthesized directly with the proposed method.The synthesized terpene-catechol resin could be separated from terpene resin and catechol on neutral alumina column with petroleum,absolute ethanol and 5% NaOH-ethanol solution as eluates.Anion exchange resin was not suitable for the separation as stationary phase due to the strong adsorption toward catechol.The chemicals of eluates were measured by UV and IR.Terpene-catechol resin can be used for preparing copolymeric coating from terpene-catechol resin with raw lacquer.

  18. THE RELATION OF CHEMICAL STRUCTURE IN CATECHOL COMPOUNDS AND DERIVATIVES TO POISON IVY HYPERSENSITIVENESS IN MAN AS SHOWN BY THE PATCH TEST.

    Science.gov (United States)

    Keil, H; Wasserman, D; Dawson, C R

    1944-10-01

    1. Additional evidence is presented in support of the view which postulates a close chemical and biologic relation between the active ingredients in poison ivy and Japan lac. 2. Biologic evidence, based on the use of the patch test in man, is presented in support of the view that the active ingredient in poison ivy is a catechol derivative with a long, unsaturated side-chain in the 3-position. 3. Of the catechol compounds and derivatives studied, group reactions in patients sensitive to poison ivy leaves or extract were exhibited by the following compounds: 3-pentadecyl catechol (100 per cent of 21 cases), 4-pentadecyl catechol (38 per cent of 21 cases), "urushiol" dimethyl ether (33 per cent of 33 cases), 3-pentadecenyl-1'-veratrole (21 per cent of 14 cases), 3-methyl catechol (14 per cent of 21 cases), and hydrourushiol dimethyl ether (10 per cent of 20 cases). It has been found that 3-geranyl catechol shows a practically constant group reactivity in persons sensitive to poison ivy. 4. The uniformly positive group reaction to 3-pentadecyl catechol is notable since this substance possesses a saturated side-chain, whereas the active ingredient in poison ivy is known to have an unsaturated side-chain. 5. The group reactivity was not restricted to the 3-position, for in some instances 4-pentadecyl catechol also gave group reactions which, however, were less intense and less frequent than those shown by 3-pentadecyl catechol. This indicates that in some cases a long side-chain in the 4 position may be effective in producing group specific reactions. 6. Only an occasional person showed sensitiveness to 3-methyl catechol (short side-chain), and in one instance the group reactivity appeared to be specific for the 3-position. 7. The position of the side-chain in the catechol configuration has some bearing on the degree and incidence of group reactions in persons hypersensitive to poison ivy. 8. Evidence is presented to indicate that the introduction of double bonds in the

  19. The synthesis, structure and activity evaluation of pyrogallol and catechol derivatives as Helicobacter pylori urease inhibitors.

    Science.gov (United States)

    Xiao, Zhu-Ping; Ma, Tao-Wu; Fu, Wei-Chang; Peng, Xiao-Chun; Zhang, Ai-Hua; Zhu, Hai-Liang

    2010-11-01

    Some pyrogallol and catechol derivatives were synthesized, and their urease inhibitory activity was evaluated by using acetohydroxamic acid (AHA), a well known Helicobacter pylori urease inhibitor, as positive control. The assay results indicate that many compounds have showed potential inhibitory activity against H. pylori urease. 4-(4-Hydroxyphenethyl)phen-1,2-diol (2a) was found to be the most potent urease inhibitor with IC(50)s of 1.5±0.2 μM for extracted fraction and 4.2±0.3 μM for intact cell, at least 10 times and 20 times lower than those of AHA (IC(50) of 17.2±0.9 μM, 100.6±13 μM), respectively. This finding indicate that 2a would be a potential urease inhibitor deserves further research. Molecular dockings of 2a into H. pylori urease active site were performed for understanding the good activity observed.

  20. Electrochemical preparation of activated graphene oxide for the simultaneous determination of hydroquinone and catechol.

    Science.gov (United States)

    Velmurugan, Murugan; Karikalan, Natarajan; Chen, Shen-Ming; Cheng, Yi-Hui; Karuppiah, Chelladurai

    2017-03-31

    This paper describes the electrochemical preparation of highly electrochemically active and conductive activated graphene oxide (aGO). Afterwards, the electrochemical properties of aGO was studied towards the simultaneous determination of hydroquinone (HQ) and catechol (CC). This aGO is prepared by the electrochemical activation of GO by various potential treatments. The resultant aGOs are examined by various physical and electrochemical characterizations. The high potential activation (1.4 to -1.5) process results a highly active GO (aGO1), which manifest a good electrochemical behavior towards the determination of HQ and CC. This aGO1 modified screen printed carbon electrode (SPCE) was furnished the sensitive detection of HQ and CC with linear concentration range from 1 to 312μM and 1 to 350μM. The aGO1 modified SPCE shows the lowest detection limit of 0.27μM and 0.182μM for the HQ and CC, respectively. The aGO1 modified SPCE reveals an excellent selectivity towards the determination of HQ and CC in the presence of 100 fold of potential interferents. Moreover, the fabricated disposable aGO1/SPCE sensor was demonstrated the determination of HQ and CC in tap water and industrial waste water.

  1. Simultaneous Determination of Hydroquinone, Catechol and Resorcinol at Graphene Doped Carbon Ionic Liquid Electrode

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    Li Ma

    2012-01-01

    Full Text Available A new composite electrode has been prepared with doping graphene into the paste consisting graphite and ionic liquid, n-octyl-pyridinum hexafluorophosphate (OPFP. This electrode shows an excellent electrochemical activity for the redox of hydroquinone (HQ, catechol (CC, and resorcinol (RS. In comparison with bare paste electrode, the redox peaks of three isomers of dihydroxybenzene can be obviously, simultaneously observed at graphene doping paste electrode. Under the optimized condition, the simultaneous determination of HQ, CC, and RS in their ternary mixture can be carried out with a differential pulse voltammetric technique. The peak currents are linear to the concentration of HQ, CC, and RS in the range form 1×10−5 to 4×10−4, 1×10−5 to 3×10−4, and 1×10−6 to 1.7×10−4 mol L−1, respectively. The limits of detection are 1.8×10−6 mol L−1 for HQ, 7.4×10−7 mol L−1 for CC, and 3.6×10−7 M for RS, respectively.

  2. Fabrication of Graphene/polydopamine Modified Electrode and Simultaneous Determination of Hydroquinone, Catechol and Resorcinol

    Institute of Scientific and Technical Information of China (English)

    QI; Ya’e; SONG; Hai; REN; Xuefeng; XU; Li

    2015-01-01

    Graphite oxide(GO) prepared by an improved Hummers method was reduced to graphene(Gr) by a hydrothermal method with Na BH4 as a reductant. Gr sample was characterized by scanning electron microscopy, X-ray diffraction and BET specific surface area analysis, respectively. The Gr-PDA modified glass carbon electrode(Gr-PDA/GCE) was designed and constructed for the simultaneous determination of hydroquinone(HQ), catechol(CC) and resorcinol(RC). The electrochemical behaviors of HQ, CC and RC on the Gr-PDA/GCE were investigated by cyclic voltammetry(CV) and differential pulse voltammetry(DPV) techniques. The results show that there are the three detections with a high peak current on the modified electrode duo to the synergetic effects of Gr and PDA, the linear response ranges for HQ and CC are 40.2–1559.6 and 24.7–1105.0 μM and the detection limits(S/N=3) are 13.4 and 8.2 μM, respectively.

  3. Catechol-O-methyltransferase val158met polymorphism predicts placebo effect in irritable bowel syndrome.

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    Kathryn T Hall

    Full Text Available Identifying patients who are potential placebo responders has major implications for clinical practice and trial design. Catechol-O-methyltransferase (COMT, an important enzyme in dopamine catabolism plays a key role in processes associated with the placebo effect such as reward, pain, memory and learning. We hypothesized that the COMT functional val158met polymorphism, was a predictor of placebo effects and tested our hypothesis in a subset of 104 patients from a previously reported randomized controlled trial in irritable bowel syndrome (IBS. The three treatment arms from this study were: no-treatment ("waitlist", placebo treatment alone ("limited" and, placebo treatment "augmented" with a supportive patient-health care provider interaction. The primary outcome measure was change from baseline in IBS-Symptom Severity Scale (IBS-SSS after three weeks of treatment. In a regression model, the number of methionine alleles in COMT val158met was linearly related to placebo response as measured by changes in IBS-SSS (p = .035. The strongest placebo response occurred in met/met homozygotes treated in the augmented placebo arm. A smaller met/met associated effect was observed with limited placebo treatment and there was no effect in the waitlist control. These data support our hypothesis that the COMT val158met polymorphism is a potential biomarker of placebo response.

  4. Antiproliferative and Antiestrogenic Activities of Bonediol an Alkyl Catechol from Bonellia macrocarpa

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    Rosa Moo-Puc

    2015-01-01

    Full Text Available The purpose of this study was to investigate antiproliferative activity of bonediol, an alkyl catechol isolated from the Mayan medicinal plant Bonellia macrocarpa. Bonediol was assessed for growth inhibition of androgen-sensitive (LNCaP, androgen-insensitive (PC-3, and metastatic androgen-insensitive (PC-3M human prostate tumor cells; toxicity on normal cell line (HEK 293 was also evaluated. Hedgehog pathway was evaluated and competitive 3H-estradiol ligand binding assay was performed. Additionally, antioxidant activity on Nrf2-ARE pathway was evaluated. Bonediol induced a growth inhibition on prostate cancer cell lines (IC50 from 8.5 to 20.6 µM. Interestingly, bonediol binds to both estrogen receptors (ERα (2.5 µM and ERβ (2.1 µM and displaces the native ligand E2 (17β-estradiol. No significant activity was found in the Hedgehog pathway. Additionally, activity of bonediol on Nrf2-ARE pathway suggested that bonediol could induce oxidative stress and activation of detoxification enzymes at 1 µM (3.8-fold. We propose that the compound bonediol may serve as a potential chemopreventive treatment with therapeutic potential against prostate cancer.

  5. Laccase Biosensor Based on Electrospun Copper/Carbon Composite Nanofibers for Catechol Detection

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    Jiapeng Fu

    2014-02-01

    Full Text Available The study compared the biosensing properties of laccase biosensors based on carbon nanofibers (CNFs and copper/carbon composite nanofibers (Cu/CNFs. The two kinds of nanofibers were prepared by electrospinning and carbonization under the same conditions. Scanning electron microscopy (SEM, X-ray diffraction (XRD and Raman spectroscopy were employed to investigate the morphologies and structures of CNFs and Cu/CNFs. The amperometric results indicated that the Cu/CNFs/laccase(Lac/Nafion/glass carbon electrode (GCE possessed reliable analytical performance for the detection of catechol. The sensitivity of the Cu/CNFs/Lac/Nafion/GCE reached 33.1 μA/mM, larger than that of CNFs/Lac/Nafion/GCE. Meanwhile, Cu/CNFs/Lac/Nafion/GCE had a wider linear range from 9.95 × 10−6 to 9.76 × 10−3 M and a lower detection limit of 1.18 μM than CNFs/Lac/Nafion/GCE. Moreover, it exhibited a good repeatability, reproducibility, selectivity and long-term stability, revealing that electrospun Cu/CNFs have great potential in biosensing.

  6. Structural mechanism of S-adenosyl methionine binding to catechol O-methyltransferase.

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    Douglas Tsao

    Full Text Available Methyltransferases possess a homologous domain that requires both a divalent metal cation and S-adenosyl-L-methionine (SAM to catalyze its reactions. The kinetics of several methyltransferases has been well characterized; however, the details regarding their structural mechanisms have remained unclear to date. Using catechol O-methyltransferase (COMT as a model, we perform discrete molecular dynamics and computational docking simulations to elucidate the initial stages of cofactor binding. We find that COMT binds SAM via an induced-fit mechanism, where SAM adopts a different docking pose in the absence of metal and substrate in comparison to the holoenzyme. Flexible modeling of the active site side-chains is essential for observing the lowest energy state in the apoenzyme; rigid docking tools are unable to recapitulate the pose unless the appropriate side-chain conformations are given a priori. From our docking results, we hypothesize that the metal reorients SAM in a conformation suitable for donating its methyl substituent to the recipient ligand. The proposed mechanism enables a general understanding of how divalent metal cations contribute to methyltransferase function.

  7. Is catechol-o-methyltransferase gene polymorphism a risk factor in the development of premenstrual syndrome?

    Science.gov (United States)

    Deveci, Esma Ozturk; Selek, Salih; Camuzcuoglu, Aysun; Hilali, Nese Gul; Camuzcuoglu, Hakan; Erdal, Mehmet Emin; Vural, Mehmet

    2014-01-01

    Objective The objective of this study was to investigate whether there was a correlation between catechol-o-methyltransferase (COMT) gene polymorphism, which is believed to play a role in the etiology of psychotic disorders, and premenstrual syndrome (PMS). Methods Fifty-three women with regular menstrual cycles, aged between 18 and 46 years and diagnosed with PMS according to the American Congress of Obstetrics and Gynecology criteria were included in this study as the study group, and 53 healthy women having no health problems were selected as the controls. Venous blood was collected from all patients included in the study and kept at -18℃ prior to analysis. Results There was no significant difference between the groups in terms of demographic features such as age, body mass index, number of pregnancies, parity, and number of children. No statistically significant difference was observed in terms of COMT gene polymorphism (p=0.61) between women in the PMS and the control groups. However, a significant difference was found between arthralgia, which is an indicator of PMS, and low-enzyme activity COMT gene (Met/Met) polymorphism (p=0.04). Conclusion These results suggested that there was no significant relationship between PMS and COMT gene polymorphism. Since we could not find a direct correlation between the COMT gene polymorphism and PMS, further studies including alternative neurotransmitter pathways are needed to find an effective treatment for this disease. PMID:25045629

  8. Colloidal stability of iron oxide nanocrystals coated with a PEG-based tetra-catechol surfactant

    Science.gov (United States)

    Mondini, Sara; Drago, Carmelo; Ferretti, Anna M.; Puglisi, Alessandra; Ponti, Alessandro

    2013-03-01

    Long-term colloidal stability of magnetic iron oxide nanoparticles (NPs) is an important goal that has not yet been fully achieved. To make an advance in our understanding of the colloidal stability of iron oxide NPs in aqueous media, we prepared NPs comprising a monodisperse (13 nm) iron oxide core coated with a PEG-based (PEG: polyethyleneglycol) surfactant. This consists of a methoxy-terminated PEG chain (MW = 5000 Da) bearing four catechol groups via a diethylenetriamine linker. The surfactant was grafted onto the nanocrystals by ligand exchange monitored by infrared spectroscopy. The colloidal stability of these nanoparticles was probed by monitoring the time evolution of the Z-average intensity-weighted radius Rh and volume-weighted size distribution Pv obtained from analysis of dynamic light scattering data. The nanoparticles showed no sign of aggregation for four months in deionized water at room temperature and also when subjected to thermal cycling between 25 and 75 °C. In 0.01 M PBS (phosphate buffered saline), aggregation (if any) is slow and partial; after 66 h, about 50% of NPs have not aggregated. Aggregation is more effective in 0.15 M NH4AcO buffer, where isolated particles are not observed after 66 h, and especially in acidic NH4AcO/AcOH buffer, where aggregation is complete within 1 h and precipitation is observed. The differing stability of the NPs in the above aqueous media is closely related to their ζ potential.

  9. Effects of Catechol O-Methyl Transferase Inhibition on Anti-Inflammatory Activity of Luteolin Metabolites.

    Science.gov (United States)

    Ha, Sang Keun; Lee, Jin-Ah; Cho, Eun Jung; Choi, Inwook

    2017-02-01

    Although luteolin is known to have potent anti-inflammatory activities, much less information has been provided on such activities of its hepatic metabolites. Luteolin was subjected to hepatic metabolism in HepG2 cells either without or with catechol O-methyl transferase (COMT) inhibitor. To identify hepatic metabolites of luteolin without (luteolin metabolites, LMs) or with COMT inhibitor (LMs+CI), metabolites were treated by β-glucuronidase and sulfatase, and found that they were composed of glucuronide and sulfate conjugates of diosmetin in LMs or these conjugates of luteolin in LMs+CI. LMs and LMs+CI were examined for their anti-inflammatory activities on LPS stimulated Raw 264.7 cells. Expression of iNOS and production of nitric oxide and pro-inflammatory cytokines such as TNF-α, IL-1β, and IL-6 were suppressed more effectively by the treatment with LMs+CI than LMs. Our data provide a new insight on possible improvement in functional properties of luteolin on target cells by modifying their metabolic pathway in hepatocytes.

  10. Catechol-O-Methyltransferase Val158Met Polymorphism Is Associated with Somatosensory Amplification and Nocebo Responses

    Science.gov (United States)

    Benson, Sven; Engler, Harald; Engler, Andrea; Hinney, Anke; Rief, Winfried; Witzke, Oliver; Schedlowski, Manfred

    2014-01-01

    A large number of unwanted adverse events and symptoms reported by patients in clinical trials are not caused by the drug provided, since most of adverse events also occur in corresponding placebo groups. These nocebo effects also play a major role in drug discontinuation in clinical practice, negatively affecting treatment efficacy as well as patient adherence and compliance. Experimental and clinical data document a large interindividual variability in nocebo responses, however, data on psychological, biological or genetic predictors of nocebo responses are lacking. Thus, with an established paradigm of behaviorally conditioned immunosuppressive effects we analyzed possible genetic predictors for nocebo responses. We focused on the genetic polymorphisms in the catechol-O-methyltransferase (COMT) gene (Val158Met) and analyzed drug specific and general side effects before and after immunosuppressive medication and subsequent placebo intake in 62 healthy male subjects. Significantly more drug-specific as well as general side effects were reported from homozygous carriers of the Val158 variant during medication as well as placebo treatment compared to the other genotype groups. Val158/Val158 carriers also had significantly higher scores in the somatosensory amplification scale (SSAS) and the BMQ (beliefs about medicine questionnaire). Together these data demonstrate potential genetic and psychological variables predicting nocebo responses after drug and placebo intake, which might be utilized to minimize nocebo effects in clinical trials and medical practice. PMID:25222607

  11. Synthesis, Characterization, and Preliminary Investigation of Cell Interaction of Magnetic Nanoparticles with Catechol-Containing Shells

    Science.gov (United States)

    Wagner, Kerstin; Seemann, Thomas; Wyrwa, Ralf; Clement, Joachim H.; Müller, Robert; Nietzsche, Sandor; Schnabelrauch, Matthias

    2010-12-01

    Superparamagnetic iron oxide cores were synthesized by co-precipitation of Fe(II) and Fe(III) salts and subsequently stabilized by coating with different catechols (levodopa, dopamine, hydrocaffeic acid, dopamine-containing carboxymethyl dextran) known to act as high-affinity, bidentate ligands for Fe(III). The prepared stable magnetic fluids were characterized with regard to their chemical composition (content of iron and shell material, Fe(II)/Fe(III) ratio) and their physical properties (size, surface charge, magnetic parameters). The nanoparticles showed no or only slight cytotoxic effects within 1 and 4 days of incubation with 3T3 fibroblast cells. Preliminary experiments were performed to study the interaction of the prepared nanoparticles with human MCF-7 breast cancer cells and leukocytes. An intense interaction of the MCF-7 cells with these particles was found whereas the leukocytes showed a lower tendency of interaction. Based on these finding, the novel magnetic nanoparticles possess the potential for use in depletion of tumor cells from peripheral blood.

  12. Genetic variation in catechol-O-methyltransferase modifies effects of clonidine treatment in chronic fatigue syndrome.

    Science.gov (United States)

    Hall, K T; Kossowsky, J; Oberlander, T F; Kaptchuk, T J; Saul, J P; Wyller, V B; Fagermoen, E; Sulheim, D; Gjerstad, J; Winger, A; Mukamal, K J

    2016-10-01

    Clonidine, an α2-adrenergic receptor agonist, decreases circulating norepinephrine and epinephrine, attenuating sympathetic activity. Although catechol-O-methyltransferase (COMT) metabolizes catecholamines, main effectors of sympathetic function, COMT genetic variation effects on clonidine treatment are unknown. Chronic fatigue syndrome (CFS) is hypothesized to result in part from dysregulated sympathetic function. A candidate gene analysis of COMT rs4680 effects on clinical outcomes in the Norwegian Study of Chronic Fatigue Syndrome in Adolescents: Pathophysiology and Intervention Trial (NorCAPITAL), a randomized double-blinded clonidine versus placebo trial, was conducted (N=104). Patients homozygous for rs4680 high-activity allele randomized to clonidine took 2500 fewer steps compared with placebo (Pinteraction=0.04). There were no differences between clonidine and placebo among patients with COMT low-activity alleles. Similar gene-drug interactions were observed for sleep (Pinteraction=0.003) and quality of life (Pinteraction=0.018). Detrimental effects of clonidine in the subset of CFS patients homozygous for COMT high-activity allele warrant investigation of potential clonidine-COMT interaction effects in other conditions.

  13. Polymorphism of the catechol-O-methyltransferase gene in Han Chinese patients with psoriasis vulgaris

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    Lin Gao

    2009-01-01

    Full Text Available Psoriasis vulgaris is defined by a series of linked cellular changes in the skin: hyperplasia of epidermal keratinocytes, vascular hyperplasia and ectasia, and infiltration of T lymphocytes, neutrophils and other types of leukocytes in the affected skin. Catechol-O-methyltransferase ( COMT 158 polymorphism can reduce the activity of the COMT enzyme that may trigger defective differentiation of keratinocytes in psoriasis. Immunocytes can degrade and inactivate catecholamines via monamine oxidase (MAO and COMT in the cells. We hypothesized that the COMT-158 G > A polymorphism was associated with the risk of psoriasis vulgaris in Han Chinese people. In a hospital-based case-control study, 524 patients with psoriasis vulgaris and 549 psoriasis-free controls were studied. COMT-158 G > A polymorphism was genotyped using the PCR sequence-specific primer (PCR-SSP technique. We found no statistically significant association between the COMT-158 allele A and the risk of psoriasis vulgaris (p = 0.739 adjusted OR = 1.03; 95% CI = 0.81-1.31. This suggests that the COMT-158 G > A polymorphism may not contribute to the etiology of psoriasis vulgaris in the Han Chinese population.

  14. Catechol-O-methyltransferase promoter hypomethylation is associated with the risk of coronary heart disease.

    Science.gov (United States)

    Zhong, Jinyan; Chen, Xiaoying; Wu, Nan; Shen, Caijie; Cui, Hanbin; Du, Weiping; Zhang, Zhaoxia; Feng, Mingjun; Liu, Junsong; Lin, Shaoyi; Zhang, Lulu; Wang, Jian; Chen, Xiaomin; Duan, Shiwei

    2016-11-01

    Catechol-O-methyltransferase (COMT) gene variation is known to be associated with the risk of acute coronary events. The purpose of the present study was to investigate the contribution of COMT promoter methylation towards the risk of coronary heart disease (CHD). COMT methylation was evaluated in 48 CHD cases and 48 well-matched non-CHD controls using bisulfite pyrosequencing technology. The results demonstrated that CHD cases had a significantly lower level of methylation at COMT CpG3 sites compared with the controls (33.77±5.71 vs. 36.42±5.00%; P=0.018). Further analysis, according to gender, showed that CpG3 methylation was associated with CHD in males (P=0.038) but not in females (P=0.253), suggesting that there is a gender disparity in the association between COMT methylation and CHD. In conclusion, it was determined that COMT CpG3 hypomethylation is associated with an increased risk of CHD in males.

  15. Revisiting catechol derivatives as robust chromogenic hydrogen donors working in alkaline media for peroxidase mimetics.

    Science.gov (United States)

    Drozd, Marcin; Pietrzak, Mariusz; Pytlos, Jakub; Malinowska, Elżbieta

    2016-12-15

    Colloidal noble metal-based nanoparticles are able to catalyze oxidation of chromogenic substrates by H2O2, similarly to peroxidases, even in basic media. However, lack of robust chromogens, which work in high pH impedes their real applications. Herein we demonstrate the applicability of selected catechol derivatives: bromopyrogallol red (BPR) and pyrogallol (PG) as chromogenic substrates for peroxidase-like activity assays, which are capable of working over wide range of pH, covering also basic values. Hyperbranched polyglycidol-stabilized gold nanoparticles (HBPG@AuNPs) were used as model enzyme mimetics. Efficiency of several methods of improving stability of substrates in alkaline media by means of selective suppression of their autoxidation by molecular oxygen was evaluated. In a framework of presented studies the impact of borate anion, applied as complexing agent for PG and BPR, on their stability and reactivity towards oxidation mediated by catalytic AuNPs was investigated. The key role of high concentration of hydrogen peroxide in elimination of non-catalytic oxidation of PG and improvement of optical properties of BPR in alkaline media containing borate was underlined. Described methods of peroxidase-like activity characterization with the use of BPR and PG can become universal tools for characterization of nanozymes, which gain various applications, among others, they are used as catalytic labels in bioassays and biosensors.

  16. Genetic influences on insight problem solving: The role of catechol-o-methyltransferase (COMT gene polymorphisms

    Directory of Open Access Journals (Sweden)

    Weili eJiang

    2015-10-01

    Full Text Available People may experience an aha moment, when suddenly realizing a solution of a puzzling problem. This experience is called insight problem solving. Several findings suggest that catecholamine-related genes may contribute to insight problem solving, among which the catechol-o-methyltransferase (COMT gene is the most promising candidate. The current study examined 753 healthy individuals to determine the associations between 7 candidate single nucleotide polymorphisms on the COMT gene and insight problem-solving performance, while considering gender differences. The results showed that individuals carrying A allele of rs4680 or T allele of rs4633 scored significantly higher on insight problem-solving tasks, and the COMT gene rs5993883 combined with gender interacted with correct solutions of insight problems, specifically showing that this gene only influenced insight problem-solving performance in males. This study presents the first investigation of the genetic impact on insight problem solving and provides evidence that highlights the role that the COMT gene plays in insight problem solving.

  17. Hyaluronan/Tannic Acid Nanoparticles Via Catechol/Boronate Complexation as a Smart Antibacterial System.

    Science.gov (United States)

    Montanari, Elita; Gennari, Arianna; Pelliccia, Maria; Gourmel, Charlotte; Lallana, Enrique; Matricardi, Pietro; McBain, Andrew J; Tirelli, Nicola

    2016-12-01

    Nanoparticles based on hyaluronic acid (HA) are designed to deliver tannic acid (TA) as an antimicrobial agent. The presence of HA makes these particles potentially useful to target bacteria that colonize cells presenting HA membrane receptors (e.g. CD44), such as macrophages. HA bearing 3-aminophenyl boronic acid groups (HA-APBA) is reacted with TA, yielding nanoparticles with a size that decreases with decreasing HA molecular weight (e.g. 200 nm for 44 kDa, 400 nm for 737 kDa). The boronate esters make the nanoparticles stable at physiological pH, but their hydrolysis in an acidic environment (pH = 5) leads to swelling/solubilization, therefore potentially allowing TA release in endosomal compartments. We have assessed the nanoparticle toxicity profile (on RAW 264.7 macrophages) and their antimicrobial activity (on E. coli and on both methicillin-sensitive and -resistant S. aureus). The antibacterial effect of HA-APBA/TA nanoparticles was significantly higher than that of TA alone, and has very similar activity to TA coformulated with a reducing agent (ascorbic acid), which indicates both the nanoparticles to protect TA catechols from oxidation, and the effective release of TA after nanoparticle internalization. Therefore, there is potential for these nanoparticles to be used in stable, effective, and potentially targetable nanoparticle-based antimicrobial formulations.

  18. Development of fed-batch profiles for efficient biosynthesis of catechol-O-methyltransferase

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    G.M. Espírito Santo

    2014-09-01

    Full Text Available Catechol-O-methyltransferase (COMT, EC 2.1.1.6 plays a crucial role in dopamine metabolism which has intimately linked this enzyme to some neurodegenerative diseases, such as Parkinson's disease. In recent years, in the attempt of developing new therapeutic strategies for Parkinson's disease, there has been a growing interest in the search for effective COMT inhibitors. In order to do so, large amounts of COMT in an active form are needed, and the best way to achieve this is by up-scaling its production through biotechnological processes. In this work, a fed-batch process for the biosynthesis of the soluble isoform of COMT in Escherichia coli is proposed. This final process was selected through the evaluation of the effect of different dissolved oxygen concentrations, carbon and nitrogen source concentrations and feeding profiles on enzymatic production and cell viability, while controlling various parameters (pH, temperature, starting time of the feeding and induction phases and carbon source concentration during the process. After several batch and fed-batch experiments, a final specific COMT activity of 442.34 nmol/h/mg with approximately 80% of viable cells at the end of the fermentation were achieved. Overall, the results described herein provide a great improvement on hSCOMT production in recombinant bacteria and provide a new and viable option for the use of a fed-batch fermentation with a constant feeding profile to the large scale production of this enzyme.

  19. Catechol-O-methyltransferase, a new target for pancreatic cancer therapy

    Science.gov (United States)

    Wu, Wenming; Wu, Qiao; Hong, Xiafei; Zhou, Li; Zhang, Jie; You, Lei; Wang, Wenze; Wu, Huanwen; Dai, Hongmei; Zhao, Yupei

    2015-01-01

    Catechol-O-methyltransferase (COMT) is an important molecule in different types of cancers. Its biological effect and therapeutic significance, however, rarely been investigated fully in pancreatic cancer. Immunohistologically, high COMT expression was significantly correlated with the longer overall survival of patients (P < 0.05), indicating its protective nature. The effects of COMT on cell growth, apoptosis, and invasion were evaluated using overexpression and silencing methods. In detail, we carried out experiments using one stably transduced and two transiently transfected pancreatic cancer cell lines in vitro, and one stably transduced cell line in vivo mice xenograft models. In vitro experiments showed that COMT inhibited cell proliferation, enhanced gemcitabine-induced apoptosis, and inhibited cell invasion in stably transduced and transiently transfected cell lines by regulating the PI3K/Akt pathway, p53, and E-cadherin. The COMT overexpressed and silenced cell lines showed significantly inhibited and enhanced growth capacities in in vivo xenograft models, respectively. In conclusion, COMT suppressed pancreatic cancer and its high expression predicted longer survival time. The interaction of COMT with the PI3K/Akt pathway makes it a potential target for therapy. PMID:25711924

  20. Laccase Biosensor Based on Electrospun Copper/Carbon Composite Nanofibers for Catechol Detection

    Science.gov (United States)

    Fu, Jiapeng; Qiao, Hui; Li, Dawei; Luo, Lei; Chen, Ke; Wei, Qufu

    2014-01-01

    The study compared the biosensing properties of laccase biosensors based on carbon nanofibers (CNFs) and copper/carbon composite nanofibers (Cu/CNFs). The two kinds of nanofibers were prepared by electrospinning and carbonization under the same conditions. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Raman spectroscopy were employed to investigate the morphologies and structures of CNFs and Cu/CNFs. The amperometric results indicated that the Cu/CNFs/laccase(Lac)/Nafion/glass carbon electrode (GCE) possessed reliable analytical performance for the detection of catechol. The sensitivity of the Cu/CNFs/Lac/Nafion/GCE reached 33.1 μA/mM, larger than that of CNFs/Lac/Nafion/GCE. Meanwhile, Cu/CNFs/Lac/Nafion/GCE had a wider linear range from 9.95 × 10−6 to 9.76 × 10−3 M and a lower detection limit of 1.18 μM than CNFs/Lac/Nafion/GCE. Moreover, it exhibited a good repeatability, reproducibility, selectivity and long-term stability, revealing that electrospun Cu/CNFs have great potential in biosensing. PMID:24561403

  1. Catechol-O-methyltransferase Val158Met polymorphism is associated with somatosensory amplification and nocebo responses.

    Directory of Open Access Journals (Sweden)

    Laura Wendt

    Full Text Available A large number of unwanted adverse events and symptoms reported by patients in clinical trials are not caused by the drug provided, since most of adverse events also occur in corresponding placebo groups. These nocebo effects also play a major role in drug discontinuation in clinical practice, negatively affecting treatment efficacy as well as patient adherence and compliance. Experimental and clinical data document a large interindividual variability in nocebo responses, however, data on psychological, biological or genetic predictors of nocebo responses are lacking. Thus, with an established paradigm of behaviorally conditioned immunosuppressive effects we analyzed possible genetic predictors for nocebo responses. We focused on the genetic polymorphisms in the catechol-O-methyltransferase (COMT gene (Val158Met and analyzed drug specific and general side effects before and after immunosuppressive medication and subsequent placebo intake in 62 healthy male subjects. Significantly more drug-specific as well as general side effects were reported from homozygous carriers of the Val158 variant during medication as well as placebo treatment compared to the other genotype groups. Val158/Val158 carriers also had significantly higher scores in the somatosensory amplification scale (SSAS and the BMQ (beliefs about medicine questionnaire. Together these data demonstrate potential genetic and psychological variables predicting nocebo responses after drug and placebo intake, which might be utilized to minimize nocebo effects in clinical trials and medical practice.

  2. Catechol-O-methyltransferase (COMT) gene modulates private self-consciousness and self-flexibility.

    Science.gov (United States)

    Wang, Bei; Ru, Wenzhao; Yang, Xing; Yang, Lu; Fang, Pengpeng; Zhu, Xu; Shen, Guomin; Gao, Xiaocai; Gong, Pingyuan

    2016-08-01

    Dopamine levels in the brain influence human consciousness. Inspired by the role of Catechol-O-methyltransferase (COMT) in inactivating dopamine in the brain, we investigated to what extent COMT could modulate individual's self-consciousness dispositions and self-consistency by genotyping the COMT Val158Met (rs4680) polymorphism and measuring self-consciousness and self-consistency and congruence in a college student population. The results indicated that COMT Val158Met polymorphism significantly modulated the private self-consciousness. The individuals with Val/Val genotype, corresponding to lower dopamine levels in the brain, were more likely to be aware of their feelings and beliefs. The results also indicated that this polymorphism modulated one's self-flexibility. The individuals with Val/Val genotype showed higher levels of stereotype in self-concept compared with those with Met/Met genotype. These findings suggest that COMT is a predictor of the individual differences in self-consciousness and self-flexibility.

  3. Schistosome and liver fluke derived catechol-estrogens and helminth associated cancers

    Directory of Open Access Journals (Sweden)

    José M Correia da Costa

    2014-12-01

    Full Text Available Infection with helminth parasites remains a persistent public health problem in developing countries. Three of these pathogens, the liver flukes Clonorchis sinensis, Opisthorchis viverrini and the blood fluke Schistosoma haematobium, are of particular concern due to their classification as Group 1 carcinogens: infection with these worms is carcinogenic. Using liquid chromatography-mass spectrometry (LC-MS/MS approaches, we identified steroid hormone like (e.g. oxysterol-like, catechol estrogen quinone-like, etc. metabolites and related DNA-adducts, apparently of parasite origin, in developmental stages including eggs of S. haematobium, in urine of people with urogenital schistosomiasis, and in the adult stage of Opisthorchis viverrini. Since these kinds of sterol derivatives are metabolized to active quinones that can modify DNA, which in other contexts can lead to breast and other cancers, helminth parasite associated sterols might induce tumor-like phenotypes in the target cells susceptible to helminth parasite associated cancers, i.e. urothelial cells of the bladder in the case of urogenital schistosomiasis and the bile duct epithelia or cholangiocytes, in the case of O. viverrini and C. sinensis. Indeed we postulate that helminth induced cancers originate from parasite estrogen-host epithelial/urothelial cell chromosomal DNA adducts, and here we review recent findings that support this conjecture.

  4. Characterization of NF-kB-mediated inhibition of catechol-O-methyltransferase

    Directory of Open Access Journals (Sweden)

    Conrad Matthew

    2009-03-01

    Full Text Available Abstract Background Catechol-O-methyltransferase (COMT, an enzyme that metabolizes catecholamines, has recently been implicated in the modulation of pain. Specifically, low COMT activity is associated with heightened pain perception and development of musculoskeletal pain in humans as well as increased experimental pain sensitivity in rodents. Results We report that the proinflammatory cytokine tumor necrosis factor α (TNFα downregulates COMT mRNA and protein in astrocytes. Examination of the distal COMT promoter (P2-COMT reveals a putative binding site for nuclear factor κB (NF-κB, the pivotal regulator of inflammation and the target of TNFα. Cell culture assays and functional deletion analyses of the cloned P2-COMT promoter demonstrate that TNFα inhibits P2-COMT activity in astrocytes by inducing NF-κB complex recruitment to the specific κB binding site. Conclusion Collectively, our findings provide the first evidence for NF-κB-mediated inhibition of COMT expression in the central nervous system, suggesting that COMT contributes to the pathogenesis of inflammatory pain states.

  5. Analysis of oxidative stress status, catalase and catechol-O-methyltransferase polymorphisms in Egyptian vitiligo patients.

    Directory of Open Access Journals (Sweden)

    Dina A Mehaney

    Full Text Available Vitiligo is the most common depigmentation disorder of the skin. Oxidative stress is implicated as one of the probable events involved in vitiligo pathogenesis possibly contributing to melanocyte destruction. Evidence indicates that certain genes including those involved in oxidative stress and melanin synthesis are crucial for development of vitiligo. This study evaluates the oxidative stress status, the role of catalase (CAT and catechol-O-Methyltransferase (COMT gene polymorphisms in the etiology of generalized vitiligo in Egyptians. Total antioxidant capacity (TAC and malondialdehyde (MDA levels as well as CAT exon 9 T/C and COMT 158 G/A polymorphisms were determined in 89 patients and 90 age and sex-matched controls. Our results showed significantly lower TAC along with higher MDA levels in vitiligo patients compared with controls. Meanwhile, genotype and allele distributions of CAT and COMT polymorphisms in cases were not significantly different from those of controls. Moreover, we found no association between both polymorphisms and vitiligo susceptibility. In conclusion, the enhanced oxidative stress with the lack of association between CAT and COMT polymorphisms and susceptibility to vitiligo in our patients suggest that mutations in other genes related to the oxidative pathway might contribute to the etiology of generalized vitiligo in Egyptian population.

  6. Genetic influences on insight problem solving: the role of catechol-O-methyltransferase (COMT) gene polymorphisms.

    Science.gov (United States)

    Jiang, Weili; Shang, Siyuan; Su, Yanjie

    2015-01-01

    People may experience an "aha" moment, when suddenly realizing a solution of a puzzling problem. This experience is called insight problem solving. Several findings suggest that catecholamine-related genes may contribute to insight problem solving, among which the catechol-O-methyltransferase (COMT) gene is the most promising candidate. The current study examined 753 healthy individuals to determine the associations between 7 candidate single nucleotide polymorphisms on the COMT gene and insight problem-solving performance, while considering gender differences. The results showed that individuals carrying A allele of rs4680 or T allele of rs4633 scored significantly higher on insight problem-solving tasks, and the COMT gene rs5993883 combined with gender interacted with correct solutions of insight problems, specifically showing that this gene only influenced insight problem-solving performance in males. This study presents the first investigation of the genetic impact on insight problem solving and provides evidence that highlights the role that the COMT gene plays in insight problem solving.

  7. Catechol-O-methyltransferase val158met Polymorphism Interacts with Sex to Affect Face Recognition Ability

    Science.gov (United States)

    Lamb, Yvette N.; McKay, Nicole S.; Singh, Shrimal S.; Waldie, Karen E.; Kirk, Ian J.

    2016-01-01

    The catechol-O-methyltransferase (COMT) val158met polymorphism affects the breakdown of synaptic dopamine. Consequently, this polymorphism has been associated with a variety of neurophysiological and behavioral outcomes. Some of the effects have been found to be sex-specific and it appears estrogen may act to down-regulate the activity of the COMT enzyme. The dopaminergic system has been implicated in face recognition, a form of cognition for which a female advantage has typically been reported. This study aimed to investigate potential joint effects of sex and COMT genotype on face recognition. A sample of 142 university students was genotyped and assessed using the Faces I subtest of the Wechsler Memory Scale – Third Edition (WMS-III). A significant two-way interaction between sex and COMT genotype on face recognition performance was found. Of the male participants, COMT val homozygotes and heterozygotes had significantly lower scores than met homozygotes. Scores did not differ between genotypes for female participants. While male val homozygotes had significantly lower scores than female val homozygotes, no sex differences were observed in the heterozygotes and met homozygotes. This study contributes to the accumulating literature documenting sex-specific effects of the COMT polymorphism by demonstrating a COMT-sex interaction for face recognition, and is consistent with a role for dopamine in face recognition. PMID:27445927

  8. Catechol-O-methyltransferase val158met polymorphism predicts placebo effect in irritable bowel syndrome.

    Science.gov (United States)

    Hall, Kathryn T; Lembo, Anthony J; Kirsch, Irving; Ziogas, Dimitrios C; Douaiher, Jeffrey; Jensen, Karin B; Conboy, Lisa A; Kelley, John M; Kokkotou, Efi; Kaptchuk, Ted J

    2012-01-01

    Identifying patients who are potential placebo responders has major implications for clinical practice and trial design. Catechol-O-methyltransferase (COMT), an important enzyme in dopamine catabolism plays a key role in processes associated with the placebo effect such as reward, pain, memory and learning. We hypothesized that the COMT functional val158met polymorphism, was a predictor of placebo effects and tested our hypothesis in a subset of 104 patients from a previously reported randomized controlled trial in irritable bowel syndrome (IBS). The three treatment arms from this study were: no-treatment ("waitlist"), placebo treatment alone ("limited") and, placebo treatment "augmented" with a supportive patient-health care provider interaction. The primary outcome measure was change from baseline in IBS-Symptom Severity Scale (IBS-SSS) after three weeks of treatment. In a regression model, the number of methionine alleles in COMT val158met was linearly related to placebo response as measured by changes in IBS-SSS (p = .035). The strongest placebo response occurred in met/met homozygotes treated in the augmented placebo arm. A smaller met/met associated effect was observed with limited placebo treatment and there was no effect in the waitlist control. These data support our hypothesis that the COMT val158met polymorphism is a potential biomarker of placebo response.

  9. Metabolism of (/sup 3/H)noradrenaline in different compartments of rat brain with respect to the role of catechol-O-methyltransferase

    Energy Technology Data Exchange (ETDEWEB)

    Koester, G.; Goede, E.; Breuer, H.

    1984-03-01

    Rats were pretreated with either reserpine or desmethylimipramine, either alone or in combination with tropolone. At either 10 min or 1 h after the intraventricular injection of (/sup 3/H)noradrenaline, in several brain regions the complete metabolic patterns were determined: normetanephrine; the glycol metabolites (methylated and nonmethylated) and their sulfate conjugates; and the acidic metabolites (methylated and non-methylated). A reserpine-induced increase in the turnover of (/sup 3/H)noradrenaline caused a transient increase of the catechol glycol followed by elevated levels of the two glycol sulfates. The stimulated (/sup 3/H)noradrenaline turnover if achieved by desmethylimipramine caused a transient increase of normetanephrine and initially lowered values of catechol glycols (both free and sulfated), which were followed by elevated levels. Drug-pretreated rats compensated for the inhibition of catechol-O-methyl-transferase by tropolone in different ways: Reserpine caused an early increase of the catechol glycol beyond the measurements in other treatment groups, whereas desmethylimipramine increased the nonmethylated carboxylic acid and glycol sulfates rather slowly to levels beyond those of other groups. The results support the existence of two compartments with a fast metabolism (an intraneuronal monoamine oxidase compartment and an extraneuronal catechol-O-methyltransferase compartment). In addition, there seems to exist another extra-neuronal space with a slow, monoamine oxidase-dependent noradrenaline turnover.

  10. Catechol estrogen formation and metabolism in brain tissue: comparison of tritium release from different positions in ring A of the steroid

    Energy Technology Data Exchange (ETDEWEB)

    Jellinck, P.H.; Hahn, E.F.; Norton, B.I.; Fishman, J.

    1984-11-01

    Catechol estrogens labeled with /sup 3/H at different positions in rings A and B of the steroid were synthesized by chemical or enzymatic methods, and their oxidative transformation by male rat brain microsomes was followed by the transfer of /sup 3/H into /sup 3/H/sub 2/O. This reaction was shown to occur more readily with the catechol estrogens than with the parent steroid and was also influenced by the position of the radiolabel. Tritium was displaced less readily from C-1 than from C-2 or C-4 of the aromatic ring. Spermine, which is known to increase cytochrome P-450-mediated hydroxylation reactions, had no effect on the release of /sup 3/H from ring A of either estradiol or 2-hydroxyestradiol with rat brain microsomes in contrast to liver. Glutathione and other thiols were able to cause a rapid loss of /sup 3/H from labeled catechol estrogens, even in the absence of tissue, but in double label experiments with (4-/sup 3/H)- and (4-/sup 14/C)2-hydroxyestradiol, the isotope ratio in the recovered catechol estrogen was unchanged. The results illustrate some of the problems in determining accurately the metabolism of estrogens by measuring /sup 3/H/sub 2/O formation when aromatic hydroxylation is involved and also highlight the possible interaction of the catechol estrogens with cellular nucleophiles such as glutathione.

  11. Polymer pendant ligand chemistry. 3. A biomimetic approach to selective metal ion removal and recovery from aqueous solution with polymer-supported sulfonated catechol and linear catechol amide ligands

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Song-Ping; Li, Wei; Franz, K.J.; Albright, R.L.; Fish, R.H. [Univ. of California, Berkeley, CA (United States)

    1995-05-24

    The design of organic ligands to selectively remove and recover metal ions from aqueous solution is a new and important area of environmental inorganic chemistry. One approach to designing organic ligands for these purposes is to use biological systems as examples for selective metal ion complexation. Thus, the authors report results on the synthesis of several biomimetically important polymer-supported, sulfonated catechol (PS-CATS), sulfonated bis(catechol) linear amide (PS-2-6-LICAMS), and sulfonated 3.3-linear tris(catechol) amide (PS-3,3-LICAMS) ligands that are chemically bonded to modified 6% cross-linked macroporous polystyrene-divinylbenzene beads (PS-DVB) for selective removal and recovery of environmentally and economically important metal ions from aqueous solution, as a function of pH. The Fe{sup 3+} ion selectivity was dramatically shown for PS-CATS, PS-2-6-LICAMS and PS-3,3-LICAMS polymer beads in competition with a similar concentration of Cu{sup 2+}, Zn{sup 2+}, Mn{sup 2+}, Ni{sup 2+}, Mg{sup 2+}, Al{sup 3+}, and Cr{sup 3+} ions at pH 1-3, while metal ion selectivity could be changed at higher pH values in the absence of Fe{sup 3+} (for example, Hg{sup 2+} at pH 3). Rates of removal and recovery of the Fe{sup 3+} ion with the PS-CATS, PS-2-6LICAMS and PS-3,3-LICAMS polymer beads were also studied as well as relative equilibrium selectivity coefficient (K{sub m}) values for all metal competition studies.

  12. Catechol as an efficient anchoring group for attachment of ruthenium-poly-pyridine photo-sensitizers to solar cells based on nanocrystalline TiO{sub 2} films

    Energy Technology Data Exchange (ETDEWEB)

    Rice, C.R.; Ward, M.D. [Bristol Univ., School of Chemistry (United Kingdom); Nazeeruddin, M.K.; Gratzel, M. [Institute of Physical Chemistry, Institute of Technology, Lab. for Photonics and Interfaces, Lausanne (Switzerland). Swiss Federal

    2000-09-01

    The Ru(II)-poly-pyridyl complexes [Ru(H{sub 2}L)(terpy)][PF{sub 6}]{sub 2} (1) and [Bu{sub 4}N] [Ru(H{sub 2}L)(NCS){sub 3}] (2) (H{sub 2}L = 4'-(3,4-4-di-hydroxy-phenyl)-2,2': 6',2''-ter-pyridine), in which H{sub 2}L is coordinated as a ter-pyridyl fragment with a catechol site pendant from the C4' position, adhere effectively to nanocrystalline TiO{sub 2} (anatase) surfaces via the pendant catechol group; incident photon-to-current conversion efficiency values of up to 50% were obtained in their photocurrent action spectra, suggesting that the catechol unit may be a convenient and effective anchoring group for attaching dyes to TiO{sub 2}-based photovoltaic cells. (authors)

  13. Electroceramics from source materials via molecular intermediates; BaTiO sub 3 from TiO sub 2 via (Ti(catecholate) sub 3 ) sup 2 minus

    Energy Technology Data Exchange (ETDEWEB)

    Davies, J.A.; Dutremez, S. (Toledo Univ., OH (USA). Dept. of Chemistry)

    1990-05-01

    Rutile or anatase may be depolymerized and complexed by sequential treatment with H{sub 2}SO{sub 4}/(NH{sub 4}){sub 2}SO{sub 4}, H{sub 2}O, and catechol/NH{sub 4}OH to produce the intermediate (NH{sub 4}){sub 2}(Ti(catecholate){sub 3}) {center dot} 2H{sub 2}O. Treatment with Ba(OH){sub 2} {center dot} 8H{sub 2}O leads to an acid-base reaction generating Ba(Ti(catecholate){sub 3}) {center dot} 3H{sub 2}O, in which the Ba:Ti ratio is held at 1:1 at the molecular level. Calcination produces BaTiO{sub 3} powder.

  14. The Role of Human Aldo-Keto Reductases in the Metabolic Activation and Detoxication of Polycyclic Aromatic Hydrocarbons: Interconversion of PAH Catechols and PAH o-Quinones.

    Science.gov (United States)

    Zhang, Li; Jin, Yi; Huang, Meng; Penning, Trevor M

    2012-01-01

    Polycyclic aromatic hydrocarbons (PAH) are ubiquitous environmental pollutants. They are procarcinogens requiring metabolic activation to elicit their deleterious effects. Aldo-keto reductases (AKR) catalyze the oxidation of proximate carcinogenic PAH trans-dihydrodiols to yield electrophilic and redox-active PAH o-quinones. AKRs are also found to be capable of reducing PAH o-quinones to form PAH catechols. The interconversion of o-quinones and catechols results in the redox-cycling of PAH o-quinones to give rise to the generation of reactive oxygen species and subsequent oxidative DNA damage. On the other hand, PAH catechols can be intercepted through phase II metabolism by which PAH o-quinones could be detoxified and eliminated. The aim of the present review is to summarize the role of human AKRs in the metabolic activation/detoxication of PAH and the relevance of phase II conjugation reactions to human lung carcinogenesis.

  15. The effects of oxygen on the yields of the thermal decomposition products of catechol under pyrolysis and fuel-rich oxidation conditions

    Energy Technology Data Exchange (ETDEWEB)

    Shiju Thomas; Elmer B. Ledesma; Mary J. Wornat [Louisiana State University, Baton Rouge, LA (United States). Department of Chemical Engineering

    2007-11-15

    In order to investigate the effects of oxygen on the distribution of thermal decomposition products from complex solid fuels, pyrolysis and fuel-rich oxidation experiments have been performed in an isothermal laminar-flow reactor, using the model fuel catechol (ortho-dihydroxybenzene), a phenol-type compound representative of structural entities in coal, wood, and biomass. The gas-phase catechol pyrolysis experiments are conducted at a residence time of 0.3 s, over a temperature range of 500-1000{sup o}C, and at oxygen ratios ranging from 0 (pure pyrolysis) to 0.92 (near stoichiometric oxidation). The pyrolysis products are analyzed by nondispersive infrared analysis and by gas chromatography with flame-ionization and mass spectrometric detection. In addition to an abundance of polycyclic aromatic hydrocarbons, catechol pyrolysis and fuel-rich oxidation produce a range of C1-C5 light hydrocarbons as well as single-ring aromatics. Quantification of the products reveals that the major products are CO, acetylene, 1,3-butadiene, phenol, benzene, vinylacetylene, ethylene, methane, cyclopentadiene, styrene, and phenylacetylene; minor products are ethane, propyne, propadiene, propylene and toluene. Under oxidative conditions, CO{sub 2} is also produced. At temperatures {lt}850{sup o}C, increases in oxygen concentration bring about increases in catechol conversion and yields of C1-C5 and single-ring aromatic products in accordance with increased rates of pyrolytic reactions, due to the enhanced free-radical pool. At temperatures {gt}850{sup o}C, catechol conversion is complete, and increases in oxygen bring about drastic decreases in the yields of virtually all hydrocarbon products, as oxidative destruction reactions dominate. Reactions responsible for the formation of the C1-C5 and single-ring aromatic products from catechol, under pyrolytic and oxidative conditions, are discussed. 74 refs., 22 figs., 1 tab.

  16. Catechol O-methyltransferase and monoamine oxidase A genotypes, and plasma catecholamine metabolites in bipolar and schizophrenic patients.

    Science.gov (United States)

    Zumárraga, Mercedes; Dávila, Ricardo; Basterreche, Nieves; Arrue, Aurora; Goienetxea, Biotza; Zamalloa, María I; Erkoreka, Leire; Bustamante, Sonia; Inchausti, Lucía; González-Torres, Miguel A; Guimón, José

    2010-01-01

    Metabolites of dopamine and norepinephrine measured in the plasma have long been associated with symptomatic severity and response to treatment in schizophrenic, bipolar and other psychiatric patients. Plasma concentrations of catecholamine metabolites are genetically regulated. The genes encoding enzymes that are involved in the synthesis and degradation of these monoamines are candidate targets for this genetic regulation. We have studied the relationship between the Val158Met polymorphism in catechol O-methyltransferase gene, variable tandem repeat polymorphisms in the monoamine oxidase A gene promoter, and plasma concentrations of 3-methoxy-4-hydroxyphenylglycol, 3,4-dihydroxyphenylacetic acid and homovanillic acid in healthy control subjects as well as in untreated schizophrenic and bipolar patients. We found that the Val158Met substitution in catechol O-methyltransferase gene influences the plasma concentrations of homovanillic and 3,4-dihydroxyphenylacetic acids. Although higher concentrations of plasma homovanillic acid were found in the high-activity ValVal genotype, this mutation did not affect the plasma concentration of 3-methoxy-4-hydroxyphenylglycol. 3,4-dihydroxyphenylacetic acid concentrations were higher in the low-activity MetMet genotype. Interestingly, plasma values 3-methoxy-4-hydroxyphenylglycol were greater in schizophrenic patients and in bipolar patients than in healthy controls. Our results are compatible with the previously reported effect of the Val158Met polymorphism on catechol O-methyltransferase enzymatic activity. Thus, our results suggest that this polymorphism, alone or associated with other polymorphisms, could have an important role in the genetic control of monoamine concentration and its metabolites.

  17. A Novel Catechol-O-Methyltransferase Variant Associated with Human Disc Degeneration

    Science.gov (United States)

    Gruber, Helen E.; Sha, Wei; Brouwer, Cory R.; Steuerwald, Nury; Hoelscher, Gretchen L.; Hanley, Edward N. Jr.

    2014-01-01

    Background: Disc degeneration and its associated low back pain are a major health care concern causing disability with a prominent role in this country's medical, social and economic structure. Low back pain is devastating and influences the quality of life for millions. Low back pain lifetime prevalence approximates 80% with an estimated direct cost burden of $86 billion per year. Back pain patients incur higher costs, greater health care utilization, and greater work loss than patients without back pain. Methods: Research was performed following approval of our Institutional Review Board. DNA was isolated, processed and amplified using routine techniques. Amplified DNA was hybridized to Affymetrix Genome-Wide Human SNP Arrays. Quality control and genotyping analysis were performed using Affymetrix Genotyping Console. The Birdseed v2 algorithm was used for genotyping analysis. 2589 SNPs were selected a priori to enter statistical analysis using lotistic regression in SAS. Results: Our objective was to search for novel single nucleotide polymorphisms (SNPs) associated with disc degeneration. Four SNPs were found to have a significant relationship to disc degeneration; three are novel. Rs165656, a new SNP found to be associated with disc degeneration, was in catechol-O-methyltransferase (COMT), a gene with well-recognized pain involvement, especially in female subjects (p=0.01). Analysis confirmed the previously association between COMT SNP rs4633 and disc degeneration. We also report two novel disc degeneration-related SNPs (rs2095019 and rs470859) located in intergenic regions upstream to thrombospondin 2. Conclusions: Findings contribute to the challenging field of disc degeneration and pain, and are important in light of the high clinical relevance of low back pain and the need for improved understanding of its fundamental basis. PMID:24904231

  18. Genetic Polymorphisms of Catechol-O-Methyltransferase Modify the Neurobehavioral Effects of Mercury in Children

    Science.gov (United States)

    Woods, James S.; Heyer, Nicholas J.; Russo, Joan E.; Martin, Michael D.; Pillai, Pradeep B.; Bammler, Theodor K.; Farin, Federico M.

    2014-01-01

    Mercury (Hg) is neurotoxic and children may be particularly susceptible to this effect. A current major challenge is identification of children who may be uniquely susceptible to Hg toxicity because of genetic disposition. This study examined the hypothesis that genetic variants of catechol-O-methyltransferase (COMT) that are reported to alter neurobehavioral functions that are also affected by Hg in adults might modify the adverse neurobehavioral effects of Hg exposure in children. Five hundred and seven children, 8–12 yr of age at baseline, participated in a clinical trial to evaluate the neurobehavioral effects of Hg from dental amalgam tooth fillings. Subjects were evaluated at baseline and at seven subsequent annual intervals for neurobehavioral performance and urinary Hg levels. Following the clinical trial, genotyping assays were performed for single-nucleotide polymorphisms (SNPs) of COMT rs4680, rs4633, rs4818, and rs6269 on biological samples provided by 330 of the trial participants. Regression-modeling strategies were employed to evaluate associations between allelic status, Hg exposure, and neurobehavioral test outcomes. Similar analysis was performed using haplotypes of COMT SNPs. Among girls, few interactions for Hg exposure and COMT variants were found. In contrast, among boys, numerous gene–Hg interactions were observed between individual COMT SNPs, as well as with a common COMT haplotype affecting multiple domains of neurobehavioral function. These findings suggest increased susceptibility to the adverse neurobehavioral effects of Hg among children with common genetic variants of COMT, and may have important implications for strategies aimed at protecting children from the potential health risks associated with Hg exposure. PMID:24593143

  19. How metal substitution affects the enzymatic activity of catechol-o-methyltransferase.

    Directory of Open Access Journals (Sweden)

    Manuel Sparta

    Full Text Available Catechol-O-methyltransferase (COMT degrades catecholamines, such as dopamine and epinephrine, by methylating them in the presence of a divalent metal cation (usually Mg(II, and S-adenosyl-L-methionine. The enzymatic activity of COMT is known to be vitally dependent on the nature of the bound metal: replacement of Mg(II with Ca(II leads to a complete deactivation of COMT; Fe(II is slightly less than potent Mg(II, and Fe(III is again an inhibitor. Considering the fairly modest role that the metal plays in the catalyzed reaction, this dependence is puzzling, and to date remains an enigma. Using a quantum mechanical / molecular mechanical dynamics method for extensive sampling of protein structure, and first principle quantum mechanical calculations for the subsequent mechanistic study, we explicate the effect of metal substitution on the rate determining step in the catalytic cycle of COMT, the methyl transfer. In full accord with experimental data, Mg(II bound to COMT is the most potent of the studied cations and it is closely followed by Fe(II, whereas Fe(III is unable to promote catalysis. In the case of Ca(II, a repacking of the protein binding site is observed, leading to a significant increase in the activation barrier and higher energy of reaction. Importantly, the origin of the effect of metal substitution is different for different metals: for Fe(III it is the electronic effect, whereas in the case of Ca(II it is instead the effect of suboptimal protein structure.

  20. Determination of catechin in green tea using a catechol oxidase biomimetic sensor

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Suellen C.; Osorio, Renata El-Hage M. de Barros; Anjos, Ademir dos; Neves, Ademir; Micke, Gustavo Amadeu; Vieira, Iolanda C. [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Dept. de Quimica]. E-mail: iolanda@qmc.ufsc.br

    2008-07-01

    A catechol oxidase biomimetic sensor, based on a novel copper(II) complex, was developed for the determination of catechin in green tea and the results were compared with those obtained by capillary electrophoresis. The dinuclear copper(II) complex, [Cu{sub 2}(HL)({mu}-CH{sub 3}COO)](ClO{sub 4}), containing the ligand N,N-[bis-(2-pyridylmethyl)]-N',N'-[(2-hydroxybenzyl)(2-hydroxy-3,5-di-tert - butylbenzyl)]-1,3-propanediamine-2-ol (H{sub 3}L), was synthesized and characterized by IR, {sup 1}H NMR and elemental analysis. The best conditions for the optimization of the biomimetic sensor were established by square wave voltammetry. The best performance for this sensor was obtained in 75:15:10% (m/m/m) of the graphite powder:nujol:copper(II) complex, 0.05 mol L{sup -1} phosphate buffer solution (pH 7.5) and frequency, pulse amplitude, scan increment at 30 Hz, 80 mV, 3.3 mV, respectively. The analytical curve was linear in the concentration range 4.95 x 10{sup -6} to 3.27 x 10{sup -5} mol L{sup -1} (r = 0.9993) with a detection limit of 2.8 x 10{sup -7} mol L{sup -1}. This biomimetic sensor demonstrated long-term stability (9 months; 800 determinations) and reproducibility with a relative standard deviation of 3.5%. The recovery of catechin from green tea samples ranged from 93.8 to 106.9% and the determination, compared with that obtained using capillary electrophoresis, was found to be acceptable at the 95% confidence level. (author)

  1. Influence of catechol-O-methyltransferase (COMT) gene polymorphisms in pain sensibility of Brazilian fibromialgia patients.

    Science.gov (United States)

    Barbosa, Flávia Regina; Matsuda, Josie Budag; Mazucato, Mendelson; de Castro França, Suzelei; Zingaretti, Sônia Marli; da Silva, Lucienir Maria; Martinez-Rossi, Nilce Maria; Júnior, Milton Faria; Marins, Mozart; Fachin, Ana Lúcia

    2012-02-01

    Fibromyalgia syndrome (FS) is a rheumatic syndrome affecting to 2-3% of individuals of productive age, mainly women. Neuroendocrine and genetic factors may play a significant role in development of the disease which is characterized by diffuse chronic pain and presence of tender points. Several studies have suggested an association between FS, especially pain sensitivity, and polymorphism of the catechol-O-methyltransferase (COMT) gene. The aim of the present study was to characterize the SNPs rs4680 and rs4818 of the COMT gene and assess its influence in pain sensitivity of patients with fibromyalgia screened by the Fibromyalgia Impact Questionnaire (FIQ). DNA was extracted from peripheral blood of 112 patients with fibromyalgia and 110 healthy individuals and was used as template in PCR for amplification of a 185-bp fragment of the COMT gene. The amplified fragment was sequenced for analyses of the SNPs rs4680 and rs4818. The frequency of mutant genotype AA of SNP rs6860 was 77.67% in patients with FS and 28.18% for the control group. For the SNP rs4818, the frequency of mutant genotype CC was 73.21 and 39.09% for patients with FS and controls, respectively. Moreover, the FIQ score was higher in patients with the homozygous mutant genotype for SNPs rs4680 (87.92 points) and rs4818 (86.14 points). These results suggest that SNPs rs4680 and rs4818 of the COMT gene may be associated with fibromyalgia and pain sensitivity in FS Brazilian patients.

  2. Preparation of Cu@Cu₂O Nanocatalysts by Reduction of HKUST-1 for Oxidation Reaction of Catechol.

    Science.gov (United States)

    Jang, Seongwan; Yoon, Chohye; Lee, Jae Myung; Park, Sungkyun; Park, Kang Hyun

    2016-11-02

    HKUST-1, a copper-based metal organic framework (MOF), has been investigated as a catalyst in various reactions. However, the HKUST-1 shows low catalytic activity in the oxidation of catechol. Therefore, we synthesized Fe₃O₄@HKUST-1 by layer-by layer assembly strategy and Cu@Cu₂O by reduction of HKUST-1 for enhancement of catalytic activity. Cu@Cu₂O nanoparticles exhibited highly effective catalytic activity in oxidation of 3,5-di-tert-butylcatechol. Through this method, MOF can maintain the original core-shell structure and be used in various other reactions with enhanced catalytic activity.

  3. Simultaneous Detection and Estimation of Catechol, Hydroquinone, and Resorcinol in Binary and Ternary Mixtures Using Electrochemical Techniques

    Directory of Open Access Journals (Sweden)

    Md. Uzzal Hossain

    2015-01-01

    Full Text Available Cyclic voltammetry (CV and differential pulse voltammetry (DPV were performed with a glassy carbon electrode (GCE modified with polyglutamic acid (PGA on the three dihydroxybenzene isomers, catechol (CT, hydroquinone (HQ, and resorcinol (RS. At bare GCE, these isomers exhibited voltammograms with highly overlapped redox peaks that impeded their simultaneous detection in binary and ternary mixtures. On the contrary, at PGA modified GCE binary and ternary mixtures of the dihydroxybenzene isomers showed well-resolved redox peaks in both CV and DPV experiments. This resolving ability of PGA modified GCE proves its potential to be exploited as an electrochemical sensor for the simultaneous detection of these isomers.

  4. Inhibition of DNA methylation by caffeic acid and chlorogenic acid, two common catechol-containing coffee polyphenols.

    Science.gov (United States)

    Lee, Won Jun; Zhu, Bao Ting

    2006-02-01

    We studied the modulating effects of caffeic acid and chlorogenic acid (two common coffee polyphenols) on the in vitro methylation of synthetic DNA substrates and also on the methylation status of the promoter region of a representative gene in two human cancer cells lines. Under conditions that were suitable for the in vitro enzymatic methylation of DNA and dietary catechols, we found that the presence of caffeic acid or chlorogenic acid inhibited in a concentration-dependent manner the DNA methylation catalyzed by prokaryotic M.SssI DNA methyltransferase (DNMT) and human DNMT1. The IC50 values of caffeic acid and chlorogenic acid were 3.0 and 0.75 microM, respectively, for the inhibition of M.SssI DNMT-mediated DNA methylation, and were 2.3 and 0.9 microM, respectively, for the inhibition of human DNMT1-mediated DNA methylation. The maximal in vitro inhibition of DNA methylation was approximately 80% when the highest concentration (20 microM) of caffeic acid or chlorogenic acid was tested. Kinetic analyses showed that DNA methylation catalyzed by M.SssI DNMT or human DNMT1 followed the Michaelis-Menten curve patterns. The presence of caffeic acid or chlorogenic acid inhibited DNA methylation predominantly through a non-competitive mechanism, and this inhibition was largely due to the increased formation of S-adenosyl-L-homocysteine (SAH, a potent inhibitor of DNA methylation), resulting from the catechol-O-methyltransferase (COMT)-mediated O-methylation of these dietary catechols. Using cultured MCF-7 and MAD-MB-231 human breast cancer cells, we also demonstrated that treatment of these cells with caffeic acid or chlorogenic acid partially inhibited the methylation of the promoter region of the RARbeta gene. The findings of our present study provide a general mechanistic basis for the notion that a variety of dietary catechols can function as inhibitors of DNA methylation through increased formation of SAH during the COMT-mediated O-methylation of these dietary

  5. Simultaneous Detection and Estimation of Catechol, Hydroquinone, and Resorcinol in Binary and Ternary Mixtures Using Electrochemical Techniques.

    Science.gov (United States)

    Hossain, Md Uzzal; Rahman, Md Toufiqur; Ehsan, Md Qamrul

    2015-01-01

    Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were performed with a glassy carbon electrode (GCE) modified with polyglutamic acid (PGA) on the three dihydroxybenzene isomers, catechol (CT), hydroquinone (HQ), and resorcinol (RS). At bare GCE, these isomers exhibited voltammograms with highly overlapped redox peaks that impeded their simultaneous detection in binary and ternary mixtures. On the contrary, at PGA modified GCE binary and ternary mixtures of the dihydroxybenzene isomers showed well-resolved redox peaks in both CV and DPV experiments. This resolving ability of PGA modified GCE proves its potential to be exploited as an electrochemical sensor for the simultaneous detection of these isomers.

  6. Development of an HTRF Assay for the Detection and Characterization of Inhibitors of Catechol-O-Methyltransferase.

    Science.gov (United States)

    Kimos, Martha; Burton, Maggi; Urbain, David; Caudron, Didier; Martini, Murielle; Famelart, Michel; Gillard, Michel; Barrow, James; Wood, Martyn

    2016-06-01

    Catechol-O-methyltransferase (COMT) plays an important role in the deactivation of catecholamine neurotransmitters and hormones. Inhibitors of COMT, such as tolcapone and entacapone, are used clinically in the treatment of Parkinson's disease. Discovery of novel inhibitors has been hampered by a lack of suitable assays for high-throughput screening (HTS). Although assays using esculetin have been developed, these are affected by fluorescence, a common property of catechol-type compounds. We have therefore evaluated a new homogenous time-resolved fluorescence (HTRF)-based assay from CisBio (Codolet, France), which measures the production of S-adenosyl-L-homocysteine (SAH). The assay has been run in both HTS and medium-throughput screening (MTS) modes. The assay was established using membranes expressing human membrane-bound COMT and was optimized for protein and time to give an acceptable signal window, good potency for tolcapone, and a high degree of translation between data in fluorescence ratio and data in terms of [SAH] produced. pIC50 values for the hits from the HTS mode were determined in the MTS mode. The assay also proved suitable for kinetic studies such as Km,app determination.

  7. The Nitrite-Scavenging Properties of Catechol, Resorcinol, and Hydroquinone: A Comparative Study on Their Nitration and Nitrosation Reactions.

    Science.gov (United States)

    Lu, Yunhao; Dong, Yanzuo; Li, Xueli; He, Qiang

    2016-10-14

    The nitration and nitrosation reactions of catechol, resorcinol, and hydroquinone (0.05 mmol/L) with sodium nitrite (0.05 mmol/L) at pH 3 and 37 °C were studied by using liquid chromatography and mass spectrometry (LC-MS) and atom charge analysis, which was aimed to provide chemical insight into the nitrite-scavenging behavior of polyphenols. The 3 benzenediols showed different mechanisms to scavenge nitrite due to their differences in hydroxyl position. Catechol was nitrated with 1 NO2 group at the hydroxyl oxygen, and resorcinol was nitrosated with 2 NO groups at the C2 and C4 (or C6 ) positions of the benzene ring. Hydroquinone could scavenge nitrite through both nitration and nitrosation mechanisms. The nitrated hydroquinone had 1 NO2 group at the hydroxyl oxygen in the molecule, while the nitrosated 1 containing 2 NO groups at the benzene ring might have 3 structure probabilities. The results may provide a structure-activity understanding on the nitrite-scavenging property of polyphenols, so as to promote their application in the food industry for the removal of possibly toxic nitrites found in many vegetables and often in processed meat products.

  8. Molecular-level spectroscopic investigations of the complexation and photodegradation of catechol to/by iron(III)

    Science.gov (United States)

    Al-Abadleh, Hind; Tofan-Lazar, Julia; Situm, Arthur; Slikboer, Samantha

    2014-05-01

    Surface water plays a crucial role in facilitating or inhibiting surface reactions in atmospheric aerosols. Little is known about the role of surface water in the complexation of organic molecules to transition metals in multicomponent aerosol systems. We will show results from real time diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) experiments for the in situ complexation of catechol to Fe(III) and its photosensitized degradation under dry and humid conditions. Catechol was chosen as a simple model for humic-like substances (HULIS) in aerosols and aged polyaromatic hydrocarbons (PAH). It has also been detected in secondary organic aerosols (SOA) formed from the reaction of hydroxyl radicals with benzene. Given the importance of the iron content in aerosols and its biogeochemistry, our studies were conducted using FeCl3. For comparison, these surface-sensitive studies were complemented with bulk aqueous ATR-FTIR, UV-vis, and HPLC measurements for structural, quantitative and qualitative information about complexes in the bulk, and potential degradation products. The implications of our studies on understanding interfacial and condensed phase chemistry relevant to multicomponent aerosols, water thin islands on buildings, and ocean surfaces containing transition metals will be discussed.

  9. Catechol functionalized aminopropyl silica gel: synthesis, characterization and preconcentrative separation of uranium(VI) from thorium(IV)

    Energy Technology Data Exchange (ETDEWEB)

    Metilda, P.; Mary Gladis, J.; Prasada Rao, T.P. [Regional Research Lab. (CSIR), Trivandrum (India)

    2005-07-01

    A novel solid phase extractant is prepared by chemically immobilizing catechol with diazotized aminopropyl silica gel. The resulting catechol functionalized silica gel (CASG) was characterized by FTIR, and microanalysis and was used for selective enrichment of uranium(VI) from other inorganic ions. The optimum pH range for maximum sorption of uranium(VI) and thorium(IV) was found to be in the range 3.5-6.0. The above actinides were eluted with 10 cm{sup 3} of 1.0 mol dm{sup -3} HCl and determined by using an Arsenazo III spectrophotometric procedure. The calibration graph was rectilinear over the uranium(VI) concentration in the range 2-100 {mu}g dm{sup -3} with a relative standard deviation of 2.15% (for 25 {mu}g of uranium(VI) present in 1.0 dm{sup 3} of sample). The validation of the developed preconcentration procedure was carried out by analyzing marine sediment (MESS-3, NRC, Canada) and soil (IAEA soil-7, Austria) reference materials. The developed preconcentration method enables a simple instruments like a spectrophotometer gave comparable values of uranium(VI) to that of standard inductively coupled plasma-mass spectrometric values during the analysis of real soil and sediment samples. (orig.)

  10. The catechol-O-methyltransferase inhibitory potential of Z-vallesiachotamine by in silicoand in vitro approaches

    Directory of Open Access Journals (Sweden)

    Carolina dos Santos Passos

    2015-08-01

    Full Text Available AbstractZ-Vallesiachotamine is a monoterpene indole alkaloid that has a β-N-acrylate group in its structure. This class of compounds has already been described in different Psychotriaspecies. Our research group observed that E/Z-vallesiachotamine exhibits a multifunctional feature, being able to inhibit targets related to neurodegeneration, such as monoamine oxidase A, sirtuins 1 and 2, and butyrylcholinesterase enzymes. Aiming at better characterizing the multifunctional profile of this compound, its effect on cathecol-O-methyltransferase activity was investigated. The cathecol-O-methyltransferase activity was evaluated in vitro by a fluorescence-based method, using S-(5′-adenosyl-l-methionine as methyl donor and aesculetin as substrate. The assay optimization was performed varying the concentrations of methyl donor (S-(5′-adenosyl-l-methionine and enzyme. It was observed that the highest concentrations of both factors (2.25 U of the enzyme and 100 µM of S-(5′-adenosyl-l-methionine afforded the more reproducible results. The in vitro assay demonstrated that Z-vallesiachotamine was able to inhibit the cathecol-O-methyltransferase activity with an IC50 close to 200 µM. Molecular docking studies indicated that Z-vallesiachotamine can bind the catechol pocket of catechol-O-methyltransferase enzyme. The present work demonstrated for the first time the inhibitory properties of Z-vallesiachotamine on cathecol-O-methyltransferase enzyme, affording additional evidence regarding its multifunctional effects in targets related to neurodegenerative diseases.

  11. Removal of Cu(II) from aqueous solution using synthetic poly(catechol-diethylenetriamine-p-phenylenediamine) particles.

    Science.gov (United States)

    Liu, Qiang; Liu, Qinze; Ruan, Zining; Chang, Xiaoqing; Yao, Jinshui

    2016-07-01

    A novel poly(catechol-diethylenetriamine-pphenylenediamine)(PCEA) adsorbent was synthesized in methanol, with chelating groups supplied by catechol and diethylenetriamine, which showed a strong removal performance and efficient adsorption toward Cu(II) ions in aqueous solution. The adsorbent was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). Besides, factors such as adsorbent dosage, pH, initial ionic and metal concentrations, contact time, and temperature on the adsorption of Cu(II) were studied. The data revealed that the adsorption followed a pseudo-second order kinetic model and the adsorption rate was influenced by the intra-particle diffusion. Furthermore, the adsorption process followed the Langmuir isotherm model, and the maximum adsorption capacity (Qm) was 44.2mg/g at 298K in simulated wastewater. The value of ΔG (kJ/mol) and ΔH (kJ/mol) also demonstrated that the adsorption process was spontaneous and endothermic. Studies revealed that PCEA particles were powerful and stable for the removal of Cu(II) in water, and it could be directly applied to the Cu(II)-contaminated water.

  12. A novel non-heme iron-containing dioxygenase. Chloridazon-catechol dioxygenase from Phenylobacterium immobilis DSM 1986.

    Science.gov (United States)

    Müller, R; Schmitt, S; Lingens, F

    1982-07-01

    Previously we purified an enzyme from Phenylobacterium immobilis DSM 1986, which cleaves the catechol derivative of the herbicide Chloridazon [5-amino-4-chloro-2-phenyl-3 (2H)-pyridazinone] in the meta position. The enzyme, which could be crystallized, proved in Ouchterlony double-diffusion tests to consist of a single protein species. No cross-reaction was observed with other meta-cleaving enzymes. Its light absorption spectrum showed a maximum at 279 nm (epsilon = 310 mM -1 cm -1), shoulders at 289 nm and 275 nm and a very weak band at around 430 nm (epsilon = 1.14 mM -1 cm -1). The amino acid analysis showed a slight excess of acidic amino acids, in agreement with the pl of 4.5. Surprisingly the enzyme per se is completely inactive, although it contains one non-dialysable iron atom per submit. It has to be activated by preincubation with ferrous ions or ascorbate. The enzyme activated this way is autoxidizable and returns to its non-activated state in the presence of oxygen. During the reaction with the substrate, this inactivation seems to be enhanced about 100 times. Since this kind of activation and inactivation is not observed in other meta-cleaving enzymes, this enzyme seems to represent a new type of a non-heme iron dioxygenase. We tentatively propose the name Chloridazon-catechol dioxygenase for this enzyme.

  13. Site-specific covalent modifications of human insulin by catechol estrogens: Reactivity and induced structural and functional changes

    Science.gov (United States)

    Ku, Ming-Chun; Fang, Chieh-Ming; Cheng, Juei-Tang; Liang, Huei-Chen; Wang, Tzu-Fan; Wu, Chih-Hsing; Chen, Chiao-Chen; Tai, Jung-Hsiang; Chen, Shu-Hui

    2016-06-01

    Proteins, covalently modified by catechol estrogens (CEs), were identified recently from the blood serum of diabetic patients and referred to as estrogenized proteins. Estrogenization of circulating insulin may occur and affect its molecular functioning. Here, the chemical reactivity of CEs towards specific amino acid residues of proteins and the structural and functional changes induced by the estrogenization of insulin were studied using cyclic voltammetry, liquid chromatography-mass spectrometry, circular dichroism spectroscopy, molecular modeling, and bioassays. Our results indicate that CEs, namely, 2- and 4-hydroxyl estrogens, were thermodynamically and kinetically more reactive than the catechol moiety. Upon co-incubation, intact insulin formed a substantial number of adducts with one or multiple CEs via covalent conjugation at its Cys 7 in the A or B chain, as well as at His10 or Lys29 in the B chain. Such conjugation was coupled with the cleavage of inter-chain disulfide linkages. Estrogenization on these sites may block the receptor-binding pockets of insulin. Insulin signaling and glucose uptake levels were lower in MCF-7 cells treated with modified insulin than in cells treated with native insulin. Taken together, our findings demonstrate that insulin molecules are susceptible to active estrogenization, and that such modification may alter the action of insulin.

  14. Polymorphisms in Catechol-O-methyltransferase Modify Treatment Effects of Aspirin on Risk of Cardiovascular Disease

    Science.gov (United States)

    Hall, Kathryn T.; Nelson, Christopher P.; Davis, Roger B.; Buring, Julie E.; Kirsch, Irving; Mittleman, Murray A.; Loscalzo, Joseph; Samani, Nilesh J.; Ridker, Paul M; Kaptchuk, Ted J.; Chasman, Daniel I.

    2014-01-01

    Objective Catechol-O-methyltransferase (COMT), a key enzyme in catecholamine metabolism, is implicated in cardiovascular, sympathetic, and endocrine pathways. This study aimed to confirm preliminary association of COMT genetic variation with incident cardiovascular disease (CVD). It further aimed to evaluate whether aspirin, a commonly used CVD prevention agent, modified the potential association of COMT with incident CVD. Approach and Results We examined COMT polymorphism rs4680 (MAF=0.47), encoding a non-synonymous methionine (met)-to-valine (val) substitution, in the Women's Genome Health Study (WGHS), a large population-based cohort of women with randomized allocation to aspirin or vitamin E compared with placebo and 10 years follow-up. Rs4680 effects were confirmed with COMT polymorphism rs4818 and also examined in CARDIoGRAM/C4D, consortia for genome-wide association studies of coronary artery disease. Among WGHS women allocated to placebo (135 events/N=5811), the rs4680 val allele was protective against incident CVD relative to the met, (HR[95%CI]=0.66[0.51-0.84], p=0.0007); an association also observed in CARDIoGRAM and C4D (combined p=2.4×10-5). In the WGHS, the rs4680 association was abolished by randomized allocation to aspirin, such that val/val women experienced higher CVD rates with aspirin allocation compared to placebo (HR[95%CI]=1.85[1.05-3.25], p=0.033) while met/met women experienced lower rates (HR[95%CI]=0.60[0.39-0.93], p=0.023). Allocation to vitamin E also conferred higher but non-significant CVD rates on val/val (HR[95%CI]=1.50 [0.83-2.70], p=0.180) compared with significantly lower rates on met/met (HR[95%CI]=0.53[0.34-0.84], p=0.006) women. Rs4818 results were similar. Conclusions Common COMT polymorphisms were associated with incident CVD, and this association was modified by randomized allocation to aspirin or vitamin E. Replication of these findings is required. PMID:25035343

  15. Bioavailability of phenanthrene in the presence of birnessite-mediated catechol polymers.

    Science.gov (United States)

    Russo, Fabio; Rao, Maria A; Gianfreda, Liliana

    2005-07-01

    Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental contaminants and contribute to the pollution of aquatic and terrestrial environments. In soil, their fate may be affected by interactions with the soil biological community and soil colloids. This study was conducted to investigate the fate of phenanthrene (Phe), selected as a representative PAH, in simplified model systems, which simulate processes naturally occurring in soil. Phe was interacted with catechol (Cat), an orthodiphenol, and common intermediate in the microbial degradation of PAHs, and birnessite (Bir), an abiotic strong oxidative catalyst abundant in soil. Two experimental conditions were investigated: Cat (5 mM)+Bir (1 mg ml(-1))+Phe (0.05 mg ml(-1)) mixed at the same time and incubated for 24 h at 25 degrees C (Cat-Bir-Phe) and Cat+Bir incubated for 24 h at 25 degrees C before Phe addition and then incubated for a further 24 h (Cat-Bir+Phe). After incubation, the systems were analysed for residual Cat and Phe, supplied with a selected Phe-degrading mixed bacterial culture, and then the microbial degradation of Phe and the growth of cells were monitored. Complex phenomena simultaneously occurred. Cat was completely removed after a 24-h incubation with Bir, and no interference by Phe in the Bir-mediated transformation of Cat was observed. Elemental analysis and UV-Vis and Fourier transfer infrared spectra showed that Cat transformation by Bir produced soluble and insoluble polymeric aggregates involving Phe. The hydrocarbon also interacted with the surfaces of Bir either previously coated (Cat-Bir+Phe sample) or not by Cat polymers. When a Phe-degrading bacterial culture was added to the systems after Bir-mediated Cat polymerisation, a different behaviour was observed in terms of Phe consumption and bacterial growth, thus suggesting differentiated availability of Phe to the microbial cells. The hydrocarbon was completely transformed in the presence of Bir and/or Bir covered by Cat

  16. Genotype status of the dopamine-related catechol-O-methyltransferase (COMT) gene corresponds with desirability of “unhealthy” foods

    NARCIS (Netherlands)

    Wallace, D.L.; Aarts, E.; d'Oleire Uquillas, F.; Dang, L.C.; Greer, S.M.; Jagust, W.J.; D'Esposito, M.

    2015-01-01

    The role of dopamine is extensively documented in weight regulation and food intake in both animal models and humans. Yet the role of dopamine has not been well studied in individual differences for food desirability. Genotype status of the dopamine-related catechol-O-methyltransferase (COMT) gene h

  17. Isolation of Alcaligenes sp strain L6 at low oxygen concentrations and degradation of 3-chlorobenzoate via a pathway not involving (chloro)catechols

    NARCIS (Netherlands)

    Krooneman, J; Wieringa, EBA; Moore, ERB; Gerritse, J; Prins, RA; Gottschal, JC

    1996-01-01

    Isolations of 3-chlorobenzoate (3CBA)-degrading aerobic bacteria under reduced O-2, partial pressures yielded organisms which metabolized 3CBA via the gentisate or the protocatechuate pathway rather than via the catechol route. The 3CBA metabolism of one of these isolates, L6, which,vas identified a

  18. Catechol-O-Methyltransferase "Val[superscript 158]Met" Genotype, Parenting Practices and Adolescent Alcohol Use: Testing the Differential Susceptibility Hypothesis

    Science.gov (United States)

    Laucht, Manfred; Blomeyer, Dorothea; Buchmann, Arlette F.; Treutlein, Jens; Schmidt, Martin H.; Esser, Gunter; Jennen-Steinmetz, Christine; Rietschel, Marcella; Zimmermann, Ulrich S.; Banaschewski, Tobias

    2012-01-01

    Background: Recently, first evidence has been reported for a gene-parenting interaction (G x E) with regard to adolescent alcohol use. The present investigation set out to extend this research using the catechol-O-methyltransferase ("COMT") "Val[superscript 158]Met" polymorphism as a genetic susceptibility factor. Moreover, the current study…

  19. Conversion of 3-chlorocatechol by various catechol 2,3-dioxygenases and sequence analysis of the chlorocatechol dioxygenase region of Pseudomonas putida GJ31

    NARCIS (Netherlands)

    Mars, Astrid E.; Kingma, Jaap; Kaschabek, Stefan R.; Reineke, Walter; Janssen, Dick B.

    1999-01-01

    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

  20. Catechol degradation on hematite/silica-gas interface as affected by gas composition and the formation of environmentally persistent free radicals

    Science.gov (United States)

    Li, Hao; Guo, Huiying; Pan, Bo; Liao, Shaohua; Zhang, Di; Yang, Xikun; Min, Chungang; Xing, Baoshan

    2016-04-01

    Environmentally persistent free radicals (EPFRs) formed on a solid particle surface have received increasing attention because of their toxic effects. However, organic chemical fate regulated by EPFRs has rarely been investigated, and this information may provide the missing link in understanding their environmental behavior. Previous studies have suggested that the reduction of transition metals is involved in EPFRs formation. We thus hypothesize that an oxidative environment may inhibit EPFRs formation in particle-gas interface, which will consequently release free radicals and accelerate organic chemical degradation. Our result indicates that a 1% hematite coating on a silica surface inhibited catechol degradation in N2, especially at low catechol loadings on solid particles (SCT). However, under an O2 environment, catechol degradation decreased when SCT was 1 μg/mg. Stable organic free radicals were observed in the N2 system with g factors in the 2.0035-2.0050 range, suggesting the dominance of oxygen-centered free radicals. The introduction of O2 into the catechol degradation system substantially decreased the free radical signals and decreased the Fe(II) content. These results were observed in both dark and light irradiation systems, indicating the ubiquitous presence of EPFRs in regulating the fate of organic chemicals.

  1. Biochar, activated carbon, and carbon nanotubes have different effects on fate of 14C-catechol and microbial community in soil

    Science.gov (United States)

    Shan, Jun; Ji, Rong; Yu, Yongjie; Xie, Zubin; Yan, Xiaoyuan

    2015-10-01

    This study investigated the effects of biochar, activated carbon (AC)-, and single-walled and multi-walled carbon nanotubes (SWCNTs and MWCNTs) in various concentrations (0, 0.2, 20, and 2,000 mg/kg dry soil) on the fate of 14C-catechol and microbial community in soil. The results showed that biochar had no effect on the mineralization of 14C-catechol, whereas AC at all amendment rates and SWCNTs at 2,000 mg/kg significantly reduced mineralization. Particularly, MWCNTs at 0.2 mg/kg significantly stimulated mineralization compared with the control soil. The inhibitory effects of AC and SWCNTs on the mineralization were attributed to the inhibited soil microbial activities and the shifts in microbial communities, as suggested by the reduced microbial biomass C and the separated phylogenetic distance. In contrast, the stimulatory effects of MWCNTs on the mineralization were attributed to the selective stimulation of specific catechol-degraders by MWCNTs at 0.2 mg/kg. Only MWCNTs amendments and AC at 2,000 mg/kg significantly changed the distribution of 14C residues within the fractions of humic substances. Our findings suggest biochar, AC, SWCNTs and MWCNTs have different effects on the fate of 14C-catechol and microbial community in soil.

  2. Biochar, activated carbon, and carbon nanotubes have different effects on fate of (14)C-catechol and microbial community in soil.

    Science.gov (United States)

    Shan, Jun; Ji, Rong; Yu, Yongjie; Xie, Zubin; Yan, Xiaoyuan

    2015-10-30

    This study investigated the effects of biochar, activated carbon (AC)-, and single-walled and multi-walled carbon nanotubes (SWCNTs and MWCNTs) in various concentrations (0, 0.2, 20, and 2,000 mg/kg dry soil) on the fate of (14)C-catechol and microbial community in soil. The results showed that biochar had no effect on the mineralization of (14)C-catechol, whereas AC at all amendment rates and SWCNTs at 2,000 mg/kg significantly reduced mineralization. Particularly, MWCNTs at 0.2 mg/kg significantly stimulated mineralization compared with the control soil. The inhibitory effects of AC and SWCNTs on the mineralization were attributed to the inhibited soil microbial activities and the shifts in microbial communities, as suggested by the reduced microbial biomass C and the separated phylogenetic distance. In contrast, the stimulatory effects of MWCNTs on the mineralization were attributed to the selective stimulation of specific catechol-degraders by MWCNTs at 0.2 mg/kg. Only MWCNTs amendments and AC at 2,000 mg/kg significantly changed the distribution of (14)C residues within the fractions of humic substances. Our findings suggest biochar, AC, SWCNTs and MWCNTs have different effects on the fate of (14)C-catechol and microbial community in soil.

  3. Catechol siderophores repress the pyochelin pathway and activate the enterobactin pathway in Pseudomonas aeruginosa: an opportunity for siderophore-antibiotic conjugates development.

    Science.gov (United States)

    Gasser, Véronique; Baco, Etienne; Cunrath, Olivier; August, Pamela Saint; Perraud, Quentin; Zill, Nicolas; Schleberger, Christian; Schmidt, Alexander; Paulen, Aurélie; Bumann, Dirk; Mislin, Gaëtan L A; Schalk, Isabelle J

    2016-03-01

    Previous studies have suggested that antibiotic vectorization by siderophores (iron chelators produced by bacteria) considerably increases the efficacy of such drugs. The siderophore serves as a vector: when the pathogen tries to take up iron via the siderophore, it also takes up the antibiotic. Catecholates are among the most common iron-chelating compounds used in synthetic siderophore-antibiotic conjugates. Using reverse transcription polymerase chain reaction and proteomic approaches, we showed that the presence of catecholate compounds in the medium of Pseudomonas aeruginosa led to strong activation of the transcription and expression of the outer membrane transporter PfeA, the ferri-enterobactin importer. Iron-55 uptake assays on bacteria with and without PfeA expression confirmed that catechol compounds imported iron into P. aeruginosa cells via PfeA. Uptake rates were between 0.3 × 10(3) and 2 × 10(3) Fe atoms/bacterium/min according to the used catechol siderophore in iron-restricted medium, and remained as high as 0.8 × 10(3) Fe atoms/bacterium/min for enterobactin, even in iron-rich medium. Reverse transcription polymerase chain reaction and proteomic approaches showed that in parallel to this switching on of PfeA expression, a repression of the expression of pyochelin (PCH) pathway genes (PCH being one of the two siderophores produced by P. aeruginosa for iron acquisition) was observed.

  4. Catechol degradation on hematite/silica-gas interface as affected by gas composition and the formation of environmentally persistent free radicals.

    Science.gov (United States)

    Li, Hao; Guo, Huiying; Pan, Bo; Liao, Shaohua; Zhang, Di; Yang, Xikun; Min, Chungang; Xing, Baoshan

    2016-04-15

    Environmentally persistent free radicals (EPFRs) formed on a solid particle surface have received increasing attention because of their toxic effects. However, organic chemical fate regulated by EPFRs has rarely been investigated, and this information may provide the missing link in understanding their environmental behavior. Previous studies have suggested that the reduction of transition metals is involved in EPFRs formation. We thus hypothesize that an oxidative environment may inhibit EPFRs formation in particle-gas interface, which will consequently release free radicals and accelerate organic chemical degradation. Our result indicates that a 1% hematite coating on a silica surface inhibited catechol degradation in N2, especially at low catechol loadings on solid particles (SCT). However, under an O2 environment, catechol degradation decreased when SCT was 1 μg/mg. Stable organic free radicals were observed in the N2 system with g factors in the 2.0035-2.0050 range, suggesting the dominance of oxygen-centered free radicals. The introduction of O2 into the catechol degradation system substantially decreased the free radical signals and decreased the Fe(II) content. These results were observed in both dark and light irradiation systems, indicating the ubiquitous presence of EPFRs in regulating the fate of organic chemicals.

  5. The effects of oxygen on the yields of polycyclic aromatic hydrocarbons formed during the pyrolysis and fuel-rich oxidation of catechol

    Energy Technology Data Exchange (ETDEWEB)

    Shiju Thomas; Mary J. Wornat [Louisiana State University, Baton Rouge, LA (United States). Department of Chemical Engineering

    2008-05-15

    To better understand the effects of oxygen on the formation and destruction of polycyclic aromatic hydrocarbons (PAH) during the burning of complex solid fuels, we have performed pyrolysis and fuel-rich oxidation experiments in an isothermal laminar-flow reactor, using the model fuel catechol (ortho-dihydroxybenzene), a phenol-type compound representative of structural entities in coal, wood, and biomass. The catechol pyrolysis experiments are conducted at a fixed residence time of 0.3 s, at nine temperatures spanning the range of 500-1000{sup o}C, and under varying oxygen ratios ranging from 0 (pure pyrolysis) to 0.92 (near stoichiometric oxidation). The PAH products, ranging in size from two to nine fused aromatic rings, have been analyzed by gas chromatography with flame-ionization and mass spectrometric detection, and by high-pressure liquid chromatography with diode-array ultraviolet-visible absorbance detection. The quantified PAH products fall into six structural classes. A comparison of product yields from pyrolysis and fuel-rich oxidation of catechol reveals that at temperatures {lt}800{sup o}C, where only two-ring PAH are produced in significant quantities, increases in oxygen concentration bring about increases in yields of the two-ring aromatics indene and naphthalene. At temperatures {gt}800{sup o}C, increases in oxygen concentration bring about dramatic decreases in the yields of all PAH products, due to oxidative destruction reactions. The smaller-ring-number PAH are produced in higher abundance under all conditions studied, and the oxygen-induced decreases in the yields of PAH are increasingly more pronounced as the PAH ring number is increased. These observations fully support our finding from catechol pyrolysis in the absence of oxygen: that PAH formation and growth occur by successive ring-buildup reactions involving the C1-C5 and single-ring aromatic products of catechol's thermal decomposition. 51 refs., 26 figs., 1 tab.

  6. Association of catechol-o-methyl transferase gene polymorphism with prostate cancer and benign prostatic hyperplasia

    Directory of Open Access Journals (Sweden)

    mir davood omrani

    2009-08-01

    Full Text Available

    • BACKGROUND: A single nucleotide variation within  atechol-o-methyl transferase (COMT gene may alter the COMT enzyme activity level. Polymorphism of Val158Met in the COMT gene has been related to malignancy. In this regard, a study was carried out to find a possible association between the COMT gene polymorphism in patients with sporadic prostate cancer (PCa and benign prostatic hyperplasia (BPH.
    • METHODS: All types of COMT158 Val/Met polymorphism were carried out using ASO-PCR method in 41 patients with prostate cancer, 193 patients with benign prostatic hyperplasia and 107 healthy male individuals.
    • RESULTS: The results of this study showed that the frequency of low producer allele A at codon 158 of the  OMT gene is significantly different in BPH group compared to normal male control group (OR, 95% CI, p value 1.95: 1.46, 2.44, 0.021, respectively. However no significant difference was noticed when the comparison was made between prostate cancer group and normal male control group and also between BPH and PCa groups.
    • CONCLUSIONS: Decreased level of catechol-o-methyl transferase gene

    • STUDY OF CATECHOL SIDEROPHORE FROM A NEWLY ISOLATED Azotobacter sp. SUP-III FOR ITS ANTIMICROBIAL PROPERTY

      Directory of Open Access Journals (Sweden)

      Shirishkumar Supanekar

      2013-12-01

      Full Text Available In present study, the isolate SUP III showed maximum siderophore production in Burk’s medium with maximum 43% decolorization of CAS reagent in liquid CAS assay. Optimum yield of siderophore was obtained at pH 7.2. The culture was identified as Azotobacter sp. based on 16S rRNA gene sequencing and phylogenetic studies using MEGA 4. The siderophore extraction and purification was achieved using XAD2 column. Colorimetric reactions prove that purified siderophore is of catecholate type. Fourier – transform infrared (FTIR analysis showed peaks at 3402 cm-1, 1652 cm-1, 1032 cm-1, and 1112 cm-1 which supported the colorimetric results. Antimicrobial activity of the purified siderophore showed significant zones of inhibition for some pathogens. This type of study has not been previously reported in this area.

    • INHIBITION KINETICS DURING THE OXIDATION OF BINARY MIXTURES OF PHENOL WITH CATECHOL, RESORCINOL AND HYDROQUINONE BY PHENOL ACCLIMATED ACTIVATED SLUDGE

      Directory of Open Access Journals (Sweden)

      C. C. Lobo

      Full Text Available Abstract In this work the aerobic degradation of phenol (PH, catechol (CA, resorcinol (RE, hydroquinone (HY and of the binary mixtures PH+CA, PH+RE, PH+HY by phenol-acclimated activated sludge was studied. Single substrate experiments show a Haldane-type dependence of the respiration rate on PH, RE and HY, while CA corresponded to the Monod model. Binary substrate experiments demonstrated that the presence of a second substrate only affected the kinetics, but not the stoichiometry of the oxidation of the compounds tested. While CA inhibited the oxidation of PH, PH inhibited the oxidation of RE and HY. A mathematical model was developed to represent the aerobic biodegradation of the phenolic compounds tested. The agreement between the proposed model and the experimental data indicates that the proposed model can be useful for predicting substrate and dissolved oxygen concentrations in bioreactors treating phenolic wastewaters.

    • Synthesis of [{sup 18}F]RO41-0960, a potent catechol-O-methyltransferase inhibitor, for PET studies

      Energy Technology Data Exchange (ETDEWEB)

      Ding, Y.-S.; Sugano, Y.; Koomen, J.; Aggarwal, D. [Brookhaven National Lab., Upton, NY (United States). Dept. of Chemistry

      1997-04-01

      Ro41-0960 (3,4-dihydroxy-5-nitro-2`-fluorobenzophenone) is a potent, fluorine containing COMT inhibitor. In order to map catechol-O-methyltransferase (COMT) in vivo with PET, no-carrier-added [{sup 18}F]Ro41-0960 was synthesized by the nucleophilic aromatic substitution of [{sup 18}F]fluoride for 2`-nitro on 3,4-dimethoxy-5,2`-dimethoxy-5,2`-dinitrobenzophenone, followed by hydrolysis with HBr. During the course of this study it was found that [{sup 18}F]fluoromethane ([{sup 18}F]CH{sub 3}F) was generated as the side product of nucleophilic aromatic substitution reaction. Various precursors with different hydroxyl protecting groups were then investigated for the effects on this side reaction. (Author).

    • Theoretical study of the Pb(II)-catechol system in dilute aqueous solution: Complex structure and metal coordination sphere determination

      Science.gov (United States)

      Lapouge, Christine; Cornard, Jean-Paul

      2010-04-01

      We investigated the unknown interaction of Pb(II) with catechol ligand in diluted aqueous solution by electronic spectroscopies combined with quantum chemical calculations. The aim of this work is the determination of the complete structure of the complex formed and particularly the metal coordination sphere. Three successive steps have been necessary to reach this goal: (i) the comparison of the experimental electronic absorption spectrum with theoretical spectra calculated from various hypothetical structures, (ii) complexation reaction pathways calculations in vacuum and with taking into account the solvent effects and finally (iii) the fluorescence emission wavelength calculations. All these investigations led to identify a monodentate complex with the monodeprotonated ligand, in which the Pb atom presents a coordination number of five. The formula of the complex is [Pb(Hcat)(HO)4]mono+.

    • Synthesis and characterization of chromium(III) Schiff base complexes: Antimicrobial activity and its electrocatalytic sensing ability of catechol

      Science.gov (United States)

      Praveen Kumar, S.; Suresh, R.; Giribabu, K.; Manigandan, R.; Munusamy, S.; Muthamizh, S.; Narayanan, V.

      2015-03-01

      A series of acyclic Schiff base chromium(III) complexes were synthesized with the aid of microwave irradiation method. The complexes were characterized on the basis of elemental analysis, spectral analysis such as UV-Visible, Fourier transform infrared (FT-IR), nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR) spectroscopies and electrospray ionization (ESI) mass spectrometry. Electrochemical analysis of the complexes indicates the presence of chromium ion in +3 oxidation state. Cr (III) ion is stabilized by the tetradentate Schiff base ligand through its nitrogen and phenolic oxygen. From the spectral studies it is understood that the synthesized chromium(III) complexes exhibits octahedral geometry. Antimicrobial activity of chromium complexes was investigated towards the Gram positive and Gram negative bacteria. In the present work, an attempt was made to fabricate a new kind of modified electrode based on chromium Schiff base complexes for the detection of catechol at nanomolar level.

    • Association between polymorphisms of the dopamine receptor D2 and catechol-o-methyl transferase genes and cognitive function.

      Science.gov (United States)

      Bolton, Jennifer L; Marioni, Riccardo E; Deary, Ian J; Harris, Sarah E; Stewart, Marlene C; Murray, Gordon D; Fowkes, F Gerry R; Price, Jackie F

      2010-09-01

      The dopaminergic neurotransmitter system of the brain is involved in working memory and other cognitive functions. Studies suggest an important role for dopamine synthesis and uptake in modulation of human cognitive processes. We studied the association between polymorphisms in the catechol-o-methyl transferase (COMT) and dopamine receptor D2 (DRD2) genes and general cognitive ability in a secondary analysis of 2091 men and women, aged 55-80 years living in Scotland. General cognitive ability 'g' was derived from five cognitive tests of different domains. COMT was not associated with cognitive ability in this population. The DRD2 C:C genotype of rs6277 was associated with decreased general cognitive ability 'g' (p = 0.003), and DRD2 rs1800497 heterozygotes had lowest mean general cognitive ability 'g' (p = 0.007). There was an indication of a potential interaction between the DRD2 SNPs.

    • Catechol conjugation with hemolymph proteins and their incorporation into the cuticle of the American cockroach, Periplaneta americana

      Energy Technology Data Exchange (ETDEWEB)

      Bailey, W.D.; Kimbrough, T.D.; Mills, R.R. [Department of Biology, Virginia Commonwealth University, Richmond, VA 23284-2012 (United States)

      1999-01-01

      Newly ecdysed American cockroaches, Periplaneta americana (six to last instar)were injected with radioactive dopamine. In addition, the reinjection of radiolabeled protein of any size resulted in the incorporation of the label into the newly sclerotized cuticle. Hemolymph proteins were synthesized in vivo using [{sup 14}C]leucine and subsequently double labeled in vivo with [{sup 3}H]dopamine. After sclerotization (7 h post-ecdysis) the cuticle was extirpated, hydrolyzed and counted. An identical ratio of {sup 14}C to {sup 3}H was found in cuticle extracts as in the double-labeled hemolymph proteins, suggesting that the phenol-bound protein was incorporated in the cuticle unchanged. It appears that the catechol bound to the proteins exists as a {beta}-glucoside. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

    • Effect of Substituents in Catechol Dye Sensitizers on Photovoltaic Performance of Type II Dye-Sensitized Solar Cells.

      Science.gov (United States)

      Ooyama, Yousuke; Kanda, Masahiro; Uenaka, Koji; Ohshita, Joji

      2015-10-01

      In order to provide a direction in molecular design of catechol (Cat) dyes for type II dye-sensitized solar cells (DSSCs), the dye-to-TiO2 charge-transfer (DTCT) characteristics of Cat dyes with various substituents and their photovoltaic performance in DSSCs are investigated. The Cat dyes with electron-donating or moderately electron-withdrawing substituents exhibit a broad absorption band corresponding to DTCT upon binding to TiO2 films, whereas those with strongly electron-withdrawing substituents exhibit weak DTCT. This study indicates that the introduction of a moderately electron-withdrawing substituent on the Cat moiety leads to not only an increase in the DTCT efficiency, but also the retardation of back electron transfer. This results in favorable conditions for the type II electron-injection pathway from the ground state of the Cat dye to the conduction band of the TiO2 electrode by the photoexcitation of DTCT bands.

    • Properties of catechol 1,2-dioxygenase in the cell free extract and immobilized extract of Mycobacterium fortuitum

      Directory of Open Access Journals (Sweden)

      A.S. Silva

      2013-01-01

      Full Text Available Polycyclic aromatic hydrocarbons (PAH are carcinogenic compounds which contaminate water and soil, and the enzymes can be used for bioremediation of these environments. This study aimed to evaluate some environmental conditions that affect the production and activity of the catechol 1,2-dioxygenase (C12O by Mycobacterium fortuitum in the cell free and immobilized extract in sodium alginate. The bacterium was grown in mineral medium and LB broth containing 250 mg L-1 of anthracene (PAH. The optimum conditions of pH (4.0-9.0, temperature (5-70 ºC, reaction time (10-90 min and the effect of ions in the enzyme activity were determined. The Mycobacterium cultivated in LB shown higher growth and the C12O activity was two-fold higher to that in the mineral medium. To both extracts the highest enzyme activity was at pH 8.0, however, the immobilized extract promoted the increase in the C12O activity in a pH range between 4.0 and 8.5. The immobilized extract increased the enzymatic activity time and showed the highest C12O activity at 45 ºC, 20 ºC higher than the greatest temperature in the cell free extract. The enzyme activity in both extracts was stimulated by Fe3+, Hg2+ and Mn2+ and inhibited by NH4+ and Cu2+, but the immobilization protected the enzyme against the deleterious effects of K+ and Mg2+ in tested concentrations. The catechol 1,2-dioxygenase of Mycobacterium fortuitum in the immobilized extract has greater stability to the variations of pH, temperature and reaction time, and show higher activity in presence of ions, comparing to the cell free extract.

    • Purification and Characterization of Catechol 1,2-Dioxygenase from Acinetobacter sp. Y64 Strain and Escherichia coli Transformants.

      Science.gov (United States)

      Lin, J; Milase, R N

      2015-12-01

      This study intends to purify and characterize catechol 1,2-dioxygenase (C1,2O) of phenol-degrading Acinetobacter sp. Y64 and of E. coli transformant. Acinetobacter sp. Y64 was capable of degrading 1000 mg/L of phenol within 14 ± 2 h at 30 °C, 160 rpm and pH of 7. One C1,2O of 36 kDa was purified using ammonium sulphate precipitation and Hitrap QFF column chromatograph with 49% recovery and a 10.6-fold increase in purity. Purified Y64 C1,2O had temperature and pH optimum at 37 °C and pH 7.7 respectively with the Michaelis constant of 17.53 µM and the maximal velocity of 1.95 U/mg, respectively. The presence of Fe(3+) or Fe(2+) enhanced the activity of Y64 C1,2O while other compounds such as Ca(2+), and EDTA had an inhibitory effect. 80% of C1,2O activity remained using 4-nitrocatechol as substrate while 2% remained using 3-methylcatechol compared with that using catechol. Y64 catA gene encoding C1,2O was amplified using PCR cloned into pET22b vector and expressed in Escherichia coli BL21 DE3 (pLysS) after transformation. Purified and cloned Y64 C1,2O show no significant differences in the biochemical properties. The phylogenetic tree based on the protein sequences indicates that these C1,2Os possess a common ancestry.

    • Inhibition of human catechol-O-methyltransferase-mediated dopamine O-methylation by daphnetin and its Phase II metabolites.

      Science.gov (United States)

      Liang, Si-Cheng; Ge, Guang-Bo; Xia, Yang-Liu; Pei-Pei, Dong; Ping, Wang; Qi, Xiao-Yi; Cai-Xia, Tu; Ling, Yang

      2016-07-20

      1. Finding and developing inhibitors of catechol-O-methyltransferase (COMT) from natural products is highly recommended. Daphnetin, a naturally occurring catechol from the family thymelaeaceae, has a chemical structure similar to several potent COMT inhibitors reported previously. Here the potential of daphnetin and its Phase II metabolites as inhibitors of COMT was investigated with human liver cytosol (HLC). 2. Daphnetin and its methylated metabolite (8-O-methyldaphnetin) were found to inhibit COMT-mediated dopamine O-methylation in a dose-dependent manner. The IC50 values for daphnetin (0.51∼0.53 μM) and 8-O-methyldaphnetin (22.5∼24.3 μM) were little affected by changes in HLC concentrations. Further kinetic analysis showed the differences in inhibition type and parameters (Ki) between daphnetin (competitive, 0.37 μM) and 8-O-methyldaphnetin (noncompetitive, 25.7 μM). Other metabolites, including glucuronidated and sulfated species, showed negligible inhibition against COMT. By using in vitro-in vivo extrapolation (IV-IVE), a 24.3-fold increase in the exposure of the COMT substrates was predicted when they are co-administrated with daphnetin. 3. With high COMT-inhibiting activity, daphnetin could serve as a lead compound for the design and development of new COMT inhibitors. Also, much attention should be paid to the clinical impact of combination of daphnetin and herbal preparations containing daphnetin with the drugs primarily cleared by COMT.

    • Biological degradation of 4-chlorobenzoic acid by a PCB-metabolizing bacterium through a pathway not involving (chloro)catechol.

      Science.gov (United States)

      Adebusoye, Sunday A

      2017-02-01

      Cupriavidus sp. strain SK-3, previously isolated on polychlorinated biphenyl mixtures, was found to aerobically utilize a wide spectrum of substituted aromatic compounds including 4-fluoro-, 4-chloro- and 4-bromobenzoic acids as a sole carbon and energy source. Other chlorobenzoic acid (CBA) congeners such as 2-, 3-, 2,3-, 2,5-, 3,4- and 3,5-CBA were all rapidly transformed to respective chlorocatechols (CCs). Under aerobic conditions, strain SK-3 grew readily on 4-CBA to a maximum concentration of 5 mM above which growth became impaired and yielded no biomass. Growth lagged significantly at concentrations above 3 mM, however chloride elimination was stoichiometric and generally mirrored growth and substrate consumption in all incubations. Experiments with resting cells, cell-free extracts and analysis of metabolite pools suggest that 4-CBA was metabolized in a reaction exclusively involving an initial hydrolytic dehalogenation yielding 4-hydroxybenzoic acid, which was then hydroxylated to protocatechuic acid (PCA) and subsequently metabolized via the β-ketoadipate pathway. When strain SK-3 was grown on 4-CBA, there was gratuitous induction of the catechol-1,2-dioxygenase and gentisate-1,2-dioxygenase pathways, even if both were not involved in the metabolism of the acid. While activities of the modified ortho- and meta-cleavage pathways were not detectable in all extracts, activity of PCA-3,4-dioxygenase was over ten-times higher than those of catechol-1,2- and gentisate-1,2-dioxygenases. Therefore, the only reason other congeners were not utilized for growth was the accumulation of CCs, suggesting a narrow spectrum of the activity of enzymes downstream of benzoate-1,2-dioxygenase, which exhibited affinity for a number of substituted analogs, and that the metabolic bottlenecks are either CCs or catabolites of the modified ortho-cleavage metabolic route.

    • Observation of UV-induced Auger features in catechol adsorbed on anatase TiO{sub 2} (101) single crystal surface

      Energy Technology Data Exchange (ETDEWEB)

      Thomas, Andrew G. [School of Physics and Astronomy and Photon Science Institute, University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Syres, Karen L. [School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom)

      2012-04-23

      We have investigated the electronic structure of catechol adsorbed on the anatase TiO{sub 2} (101) surface under illumination with ultraviolet (UV) light (4.75 eV) using resonant photoemission spectroscopy. UV illumination results in the appearance of a strong Ti MVV (M refers to photoionization of 3p level and VV the Auger decay process via the valence levels) feature at a kinetic energy of 26.2 eV. This is attributed to the creation of localised states following catechol to Ti-3d excitation by the UV source. A sharp resonance attributed to excitation from Ti 3p states into these localised states is observed in constant final state spectra.

    • Mechanistic study of electrochemical oxidation of catechols in the presence of 4-hydroxy-1-methyl-2(1H)-quinolone

      Energy Technology Data Exchange (ETDEWEB)

      Fakhari, Ali Reza [Department of Chemistry, Faculty of Science, University of Shahid Beheshti, Tehran 19835389 (Iran, Islamic Republic of)]. E-mail: a-zavareh@sbu.ac.ir; Nematollahi, Davood [Department of Chemistry, Faculty of Science, University of Bu-Ali-Sina, Hamadan (Iran, Islamic Republic of); Moghaddam, Abdolmajid Bayandori [Department of Chemistry, Faculty of Science, University of Shahid Beheshti, Tehran 19835389 (Iran, Islamic Republic of)

      2005-09-20

      Electrochemical oxidation of catechols (1a-1c) has been studied in the presence of 4-hydroxy-1-methyl-2(1H)-quinolone (3) as a nucleophile in aqueous solution using cyclic voltammetry and controlled-potential coulometry. The results indicate that the quinones derived from catechols (1a-1c) participate in Michael addition reactions with 3 to form the corresponding benzofuran (or isochromeno[4,3-c]quinoline) derivatives (6a-6c). The electrochemical synthesis of (6a-6c) has been successfully performed in an undivided cell in good yield and purity. The oxidation mechanism was deduced from voltammetric data and by coulometry at controlled-potential. The products have been characterized after purification by IR, {sup 1}H NMR, {sup 13}C NMR and MS.

  1. Formation of environmentally persistent free radicals as the mechanism for reduced catechol degradation on hematite-silica surface under UV irradiation.

    Science.gov (United States)

    Li, Hao; Pan, Bo; Liao, Shaohua; Zhang, Di; Xing, Baoshan

    2014-05-01

    Iron is rich in soils, and is recently reported to form stable complexes with organic free radicals, generating environmentally persistent free radicals (EPFRs). The observation may challenge the common viewpoint that iron is an effective catalyst to facilitate the degradation of various organic chemicals. But no study was specifically designed to investigate the possible inhibited degradation of organic chemicals because of the formation of EPFRs in dry environment. We observed that catechol degradation under UV irradiation was decreased over 20% in silica particles coated with 1% hematite in comparison to uncoated silica particles. Stabilized semiquinone or quinine and phenol radicals were involved in HMT-silica system. EPFR formation was thus the reason for the reduced catechol degradation on HMT-silica surface under UV irradiation at ambient temperature. EPFRs should be incorporated in the studies of organic contaminants geochemical behavior, and will be a new input in their environmental fate modeling.

  2. Protective Role of Maternal P.VAL158MET Catechol-O-methyltransferase Polymorphism against Early-Onset Preeclampsia and its Complications

    Directory of Open Access Journals (Sweden)

    Krnjeta Tijana

    2016-09-01

    Full Text Available Background: Up until now there have been contradictory data about the association between p.Val158Met catechol-O-methyltransferase (COMT polymorphism and risk of preeclampsia (PE. The goal of this study was to assess the potential correlation between p.Val158Met COMT polymorphism and risk of early-onset PE, risk of a severe form of early-onset PE, as well as risk of small-for-gestationalage (SGA complicating PE.

  3. 苯酚双氧水氧化法制邻、对苯二酚%CATECHOL AND HYDROQUINONE FROM HYDROXYLATION OF PHENOL BY HYDROGEN PEROXIDE

    Institute of Scientific and Technical Information of China (English)

    崔咪芬; 乔旭

    2001-01-01

    For the preparation of catechol and hydroquinone from catalytic hydroxylation of phenol by lower concentration aqueous hydrogen peroxide. In the experiment, aqueous phenol solution was added to the reactor in batch to hydrogen peroxide drop by drop. Effects of different molar ratio of phenol and hydrogen peroxide、initial concentration of phenol、reactive temperature etc. on conversion of phenol and selectivity of catechol and hydroquinone were investigated. Under the suitable conditions, the mixture gave 40% conversion of phenol and 90% selectivity of catechol and hydroquinone. The molar ratio of catechol and hydroquinone was 1.6~1.8.%对苯酚、双氧水合成邻、对苯二酚的反应体系,采用苯酚溶液一次性加入反应器、双氧水连续滴加的半间歇操作方式,研究了苯酚与双氧水的摩尔配比、苯酚初浓度、双氧水滴加速率、反应温度等因素对苯酚转化率和邻、对苯二酚选择性的影响。在适宜的工艺条件下,苯酚的转化率可达到40%左右,苯二酚的总选择性可达到90%左右,邻/对比为1.6~1.8。

  4. Cytoprotective Effect of Caffeic Acid Phenethyl Ester (CAPE) and Catechol Ring-Fluorinated CAPE Derivatives Against Menadione-Induced Oxidative Stress in Human Endothelial Cells

    Science.gov (United States)

    2006-03-31

    chlorogenic acid , and rosmari- nic acid did not display any cytoprotective effect in this assay at 15 lM (data not shown). Within the same pas- sage of HUVEC...Cytoprotective effect of caffeic acid phenethyl ester (CAPE) and catechol ring-fluorinated CAPE derivatives against menadione-induced oxidative...accepted 13 March 2006 Available online 31 March 2006 Abstract—Caffeic acid phenethyl ester (CAPE), a natural polyphenolic compound with many

  5. Speciation analysis of aluminium(III) in natural waters and biological fluids by complexing with various catechols followed by differential pulse voltammetry detection.

    Science.gov (United States)

    Liu, Jian; Bi, Shuping; Yang, Li; Gu, Xiaodong; Ma, Pengju; Gan, Ning; Wang, Xianlong; Long, Xiufeng; Zhang, Fuping

    2002-12-01

    The biological effects of aluminium have received much attention in recent years. Speciation of Al is of basic relevance as it concerns its reactivity and bioavailability. A differential pulse voltammetry (DPV) procedure is proposed for speciation analysis of Al(III) in natural waters and biological fluids using six catechols (L-dopa, dopamine, epinephrine, norepinephrine, caffeic acid and o-benzenediol) as electroactive ligands. The decrease of the DPV anodic peak current for each catechol ligand is linear with the increase of Al concentration. This speciation analysis idea is based on the measurement of the complexation capacity, namely, different affinities of Al(III) for catechols and organic ligands under two pH conditions. The labile monomeric Al fraction (mainly inorganic aluminium) is determined at pH 4.6, while the total monomeric Al fraction is determined at pH 8.5. The principle for Al(III) speciation analysis by an electrochemical method is discussed. This sensitive and simple fractionation method is successfully applied to the speciation analysis of Al in natural waters and the results agree well with those of Driscoll's method. The speciation analysis of Al in biological fluids is also explored and the results are compared with those obtained by ultrafiltration and dialysis. Compared with other speciation protocols the electrochemical method possesses some remarkable advantages: rapidity, high sensitivity, cheap instrumentation and a simple operation procedure.

  6. Effect of cobalt doping level of ferrites in enhancing sensitivity of analytical performances of carbon paste electrode for simultaneous determination of catechol and hydroquinone.

    Science.gov (United States)

    Lakić, Mladen; Vukadinović, Aleksandar; Kalcher, Kurt; Nikolić, Aleksandar S; Stanković, Dalibor M

    2016-12-01

    This work presents the simultaneous determination of catechol (CC) and hydroquinone (HQ), employing a modified carbon paste electrode (CPE) with ferrite nanomaterial. Ferrite nanomaterial was doped with different amount of cobalt and this was investigated toward simultaneous oxidation of CC and HQ. It was shown that this modification strongly increases electrochemical characteristics of the CPE. Also, electrocatalytic activity of such materials strongly depends on the level of substituted Co in the ferrite nanoparticles. The modified electrodes, labeled as CoFerrite/CPE, showed two pairs of well-defined redox peaks for the electrochemical processes of catechol and hydroquinone. Involving of ferrite material in the structure of CPE, cause increase in the potentials differences between redox couples of the investigated compounds, accompanied with increases in peaks currents. Several important parameters were optimized and calibration curves, with limits of detection (LOD) of 0.15 and 0.3µM for catechol and hydroquinone, respectively, were constructed by employing amperometric detection. Effect of possible interfering compounds was also studied, and proposed method was successfully applied for CC and HQ quantification in real samples.

  7. Substrate-dependent aromatic ring fission of catechol and 2-aminophenol with O2 catalyzed by a nonheme iron complex of a tripodal N4 ligand.

    Science.gov (United States)

    Lakshman, Triloke Ranjan; Chatterjee, Sayanti; Chakraborty, Biswarup; Paine, Tapan Kanti

    2016-06-07

    The catalytic reactivity of an iron(ii) complex [(TPA)Fe(II)(CH3CN)2](2+) (1) (TPA = tris(2-pyridylmethyl)amine) towards oxygenative aromatic C-C bond cleavage of catechol and 2-aminophenol is presented. Complex 1 exhibits catalytic and regioselective C-C bond cleavage of 3,5-di-tert-butylcatechol (H2DBC) to form intradiol products, whereas it catalyzes extradiol-type C-C bond cleavage of 2-amino-4,6-di-tert-butylphenol (H2AP). The catalytic reactions are found to be pH-dependent and the complex exhibits maximum turnovers at pH 5 in acetonitrile-phthalate buffer. An iron(iii)-catecholate complex [(TPA)Fe(III)(DBC)](+) (2) is formed in the ring cleavage of catechol. In the extradiol-type cleavage of H2AP, an iron(iii)-2-iminobenzosemiquinonate complex [(TPA)Fe(III)(ISQ)](2+) (3) (ISQ = 4,6-di-tert-butyl-2-iminobenzosemiquinonate radical anion) is observed in the reaction pathway. This work shows the importance of the nature of 'redox non-innocent' substrates in governing the mode of ring fission reactivity.

  8. The Use of Screen-Printed Electrodes in a Proof of Concept Electrochemical Estimation of Homocysteine and Glutathione in the Presence of Cysteine Using Catechol

    Science.gov (United States)

    Lee, Patricia T.; Lowinsohn, Denise; Compton, Richard G.

    2014-01-01

    Screen printed electrodes were employed in a proof of concept determination of homocysteine and glutathione using electrochemically oxidized catechol via a 1,4-Michael addition reaction in the absence and presence of cysteine, and each other. Using cyclic voltammetry, the Michael reaction introduces a new adduct peak which is analytically useful in detecting thiols. The proposed procedure relies on the different rates of reaction of glutathione and homocysteine with oxidized catechol so that at fast voltage scan rates only homocysteine is detected in cyclic voltammetry. At slower scan rates, both glutathione and homocysteine are detected. The combination of the two sets of data provides quantification for homocysteine and glutathione. The presence of cysteine is shown not to interfere provided sufficient high concentrations of catechol are used. Calibration curves were determined for each homocysteine and glutathione detection; where the sensitivities are 0.019 μA·μM−1 and 0.0019 μA·μM−1 and limit of detections are ca. 1.2 μM and 0.11 μM for homocysteine and glutathione, respectively, within the linear range. This work presents results with potential and beneficial use in re-useable and/or disposable point-of-use sensors for biological and medical applications. PMID:24926695

  9. The Use of Screen-Printed Electrodes in a Proof of Concept Electrochemical Estimation of Homocysteine and Glutathione in the Presence of Cysteine Using Catechol

    Directory of Open Access Journals (Sweden)

    Patricia T. Lee

    2014-06-01

    Full Text Available Screen printed electrodes were employed in a proof of concept determination of homocysteine and glutathione using electrochemically oxidized catechol via a 1,4-Michael addition reaction in the absence and presence of cysteine, and each other. Using cyclic voltammetry, the Michael reaction introduces a new adduct peak which is analytically useful in detecting thiols. The proposed procedure relies on the different rates of reaction of glutathione and homocysteine with oxidized catechol so that at fast voltage scan rates only homocysteine is detected in cyclic voltammetry. At slower scan rates, both glutathione and homocysteine are detected. The combination of the two sets of data provides quantification for homocysteine and glutathione. The presence of cysteine is shown not to interfere provided sufficient high concentrations of catechol are used. Calibration curves were determined for each homocysteine and glutathione detection; where the sensitivities are 0.019 µA·µM−1 and 0.0019 µA·µM−1 and limit of detections are ca. 1.2 µM and 0.11 µM for homocysteine and glutathione, respectively, within the linear range. This work presents results with potential and beneficial use in re-useable and/or disposable point-of-use sensors for biological and medical applications.

  10. The effect of substituents on the surface modification of anatase nanoparticles with catecholate-type ligands: a combined DFT and experimental study.

    Science.gov (United States)

    Savić, Tatjana D; Čomor, Mirjana I; Nedeljković, Jovan M; Veljković, Dušan Ž; Zarić, Snežana D; Rakić, Vesna M; Janković, Ivana A

    2014-10-14

    The surface modification of nanocrystalline TiO2 particles (45 Å) with catecholate-type ligands having different electron donating/electron withdrawing substituent groups, specifically 3-methylcatechol, 4-methylcatechol, 3-methoxycatechol, 3,4-dihydroxybenzaldehyde and 4-nitrocatechol, was found to alter the optical properties of nanoparticles in a similar way to catechol. The formation of the inner-sphere charge-transfer (CT) complexes results in a red shift of the semiconductor absorption compared to unmodified nanocrystallites and a reduction of the effective band gap, being slightly less pronounced in the case of electron withdrawing substituents. The investigated ligands have the optimal geometry for binding to surface Ti atoms, resulting in ring coordination complexes of the catecholate type (binuclear bidentate binding-bridging) thus restoring six-coordinated octahedral geometry of surface Ti atoms. From the absorption measurements (Benesi-Hildebrand plot), the stability constants in methanol/water = 90/10 solutions at pH 2 in the order of 10(3) M(-1) have been determined. The binding structures were investigated by using FTIR spectroscopy. Thermal stability of CT-complexes was investigated by using TG/DSC/MS analysis. Quantum chemical calculations on model systems using density functional theory (DFT) were performed to obtain the vibrational frequencies of charge transfer complexes, and the calculated values were compared with the experimental data.

  11. Regiospecific attack of nitrogen and sulfur nucleophiles on quinones derived from poison oak/ivy catechols (urushiols) and analogues as models for urushiol-protein conjugate formation.

    Science.gov (United States)

    Liberato, D J; Byers, V S; Dennick, R G; Castagnoli, N

    1981-01-01

    Attempts to characterize potential biologically important covalent interactions between electrophilic quinones derived from catechols present in poison oak/ivy (urushiol) and biomacromolecules have led to the analysis of model reactions involving sulfur and amino nucleophiles with 3-heptadecylbenzoquinone. Characterization of the reaction products indicates that this quinone undergoes regiospecific attack by (S)-N-acetylcysteine at C-6 and by 1-aminopentane at C-5. The red solid obtained with 1-aminopentane proved to be 3-heptadecyl-5-(pentylamino)-1,2-benzoquinone. Analogous aminobenzoquinones were obtained with the quinones derived from the 4- and 6-methyl analogues of 3-pentadecylcatechol. All three adducts absorbed visible light at different wavelengths. When the starting catechols were incubated with human serum albumin almost identical chromophores were formed. These results establish that cathechols responsible for the production of the poison oak/ivy contact dermatitis in humans undergo a sequence of reactions in the presence of human serum albumin that lead to covalent attachment of the catechols to the protein via carbon-nitrogen bonds. Estimations of the extent of this binding indicate that, at least with human serum albumin, the reaction is quantitative.

  12. [Preparation of OMC-Au/L-Lysine/Au modified glassy carbon electrode and the study on its detection response to hydroquinone and catechol].

    Science.gov (United States)

    Zhou, Yao-Yu; Tang, Lin; Li, Zhen; Liu, Yuan-Yuan; Yang, Gui-De; Wu, Meng-Shi; Lei, Xiao-Xia; Zheng, Guang-Ming

    2013-03-01

    Ordered mesoporous carbon-Au nanoparticles (OMC-Au) nanocomposites were synthesized by a one-step chemical reduction route, and an OMC-Au/L-Lysine/Au composite film-modified glassy carbon electrode (GCE) was constructed. The microstructure of OMC and OMC-Au/L-Lysine/Au composite films were characterized by SEM, and the preparation process of OMC-Au/L-Lysine/Au modified glassy carbon electrode was investigated using cyclic voltammetry and electrochemical impedance spectroscopy. The electrocatalytic oxidation of hydroquinone and catechol on the modified electrode was discussed by differential pulse voltammetry in this study, and a sensor for separate determination of hydroquinone and catechol based on OMC-Au/L-Lysine/Au modified glassy carbon electrode was developed. Under the optimal conditions, the cathodic peak current was linearly related to hydroquinone concentration over ranges from 1.0 x 10(-6) mol x L(-1) to 8.0 x 10(-4) mol x L(-1) with a detection limit of 3.0 x 10(-7) mol x L(-1), and linearly related to catechol concentration from 1.0 x 10(-7) mol x L(-1) to 8.0 x 10(-5) mol x L(-1) with a detection limit of 8.0 x 10(-7) mol x L(-1).

  13. 流动注射-Luminol/Tween20化学发光体系测定邻苯二酚%Determination of catechol with flow injection-luminol/Tween 20 chemiluminescence system

    Institute of Scientific and Technical Information of China (English)

    谢建新; 伍贤学

    2013-01-01

    基于邻苯二酚对luminol-Tween 20化学发光体系的强烈的抑制作用,建立了一种简单、灵敏的luminol-Tween 20化学发光体系测定邻苯二酚的新方法.在最佳实验条件下,方法的检出限为5.0 ×l0-10mo1/L,线性范围为1.0 × 10-9mol/L~1.0×10-2mol/L,对5.0×10-8mol/L邻苯二酚进行平行测定11次,其RSD为4.1%.该方法可应用于自来水样中邻苯二酚的测定.%A simple and sensitive flow injection-chemiluminescence (CL) system of luminol-Tween 20 for the direct determination of catechol was developed.Proposed method was based on the strongly inhibition effect of catechol on the CL intensity of luminol-Tween 20 system.Under the optimial conditions,catechol was determined.The detection limit of the method is 5.0 × 10-10mol/L for catechol,the linear range for catechol is 1.0 × 10-9mol/L ~ 1.0 × 10-7mol/L.The relative standard deviation is 4.1% for 5.0 × 10-8mol/L catechol in 11 repeated measurements.The method was successfully applied to the detection of catechol in tap water samples.

  14. Generation of membrane-bound catechol-O-methyl transferase deficient mice with disctinct sex dependent behavioral phenotype.

    Science.gov (United States)

    Tammimaki, A; Aonurm-Helm, A; Zhang, F P; Poutanen, M; Duran-Torres, G; Garcia-Horsman, A; Mannisto, P T

    2016-12-01

    Catechol-O-methyltransferase (COMT) has two isoforms: soluble (S-COMT), which resides in the cytoplasm, and membrane-bound (MB-MT), anchored to intracellular membranes. COMT is involved in the O-methylation of L-DOPA, dopamine and other catechols. The exact role of MB-COMT is still mostly unclear. We wanted to create a novel genetically modified mouse model that specifically lacks MB-COMT activity and to study their behavioral phenotype. MB-COMT knock-in mutant mice were generated by introducing two point mutations in exon 2 of the Comt gene (ATGCTG->GAGCTC disabling the function of the P2 promoter and allowing only the P1-regulated S-COMT transcription. The first mutation changes methionine to glutamic acid whereas the second one does not affect coding. The expression of the two COMT isoforms, total COMT activity in several areas of the brain and peripheral tissues and extracellular dopamine concentrations after L-DOPA (10 mg/kg) and carbidopa (30 mg/kg) subcutaneous administration were assessed. A battery of behavioral tests was performed to compare MB-COMT deficient mice and their wild type littermates of both sexes. MB-COMT deficient mice were seemingly normal, bred usually and had unaltered COMT activity in the brain and periphery despite a complete lack of the MB-COMT protein. MB-COMT deficient male mice showed higher extracellular dopamine levels than their wild-type littermates in the striatum, but not in the mPFC. In addition, the MB-COMT deficient male mice exhibited a distinct endophenotype characterized by schizophrenia-related behaviors like aggressive behavior and reduced prepulse inhibition. They also had prolonged immobility in the tail suspension test. Both sexes were sensitized to acute pain and had normal motor activity but disturbed short-term memory. Hence the behavioral phenotype was not limited to schizophrenia-related endophenotype and some behavioural findings were not sex-dependent. Our findings indicate that MB-COMT is critical for

  15. Catechol-o-methyltransferase gene polymorphism modifies the effect of coffee intake on incidence of acute coronary events.

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    Pertti Happonen

    Full Text Available BACKGROUND: The role of coffee intake as a risk factor for coronary heart disease (CHD has been debated for decades. We examined whether the relationship between coffee intake and incidence of CHD events is dependent on the metabolism of circulating catecholamines, as determined by functional polymorphism of the catechol-O-methyltransferase (COMT gene. METHODOLOGY/PRINCIPAL FINDINGS: In a cohort of 773 men who were 42 to 60 years old and free of symptomatic CHD at baseline in 1984-89, 78 participants experienced an acute coronary event during an average follow-up of 13 years. In logistic regression adjusting for age, smoking, family history of CHD, vitamin C deficiency, blood pressure, plasma cholesterol concentration, and diabetes, the odds ratio (90% confidence interval comparing heavy coffee drinkers with the low activity COMT genotype with those with the high activity or heterozygotic genotypes was 3.2 (1.2-8.4. Urinary adrenaline excretion increased with increasing coffee intake, being over two-fold in heavy drinkers compared with nondrinkers (p = 0.008 for trend. CONCLUSIONS/SIGNIFICANCE: Heavy coffee consumption increases the incidence of acute coronary events in men with low but not high COMT activity. Further studies are required to determine to which extent circulating catecholamines mediate the relationship between coffee intake and CHD.

  16. Genetic contribution of catechol-O-methyltransferase polymorphism (Val158Met) in children with chronic tension-type headache.

    Science.gov (United States)

    Fernández-de-las-Peñas, César; Ambite-Quesada, Silvia; Rivas-Martínez, Inés; Ortega-Santiago, Ricardo; de-la-Llave-Rincón, Ana Isabel; Fernández-Mayoralas, Daniel M; Pareja, Juan A

    2011-10-01

    Our aim was to investigate the relationship between Val158Met polymorphisms, headache, and pressure hypersensitivity in children with chronic tension-type headache (CTTH). A case-control study with blinded assessor was conducted. Seventy children with CTTH associated with pericranial tenderness and 70 healthy children participated. After amplifying Val158Met polymorphism by polymerase chain reactions, we assessed genotype frequencies and allele distributions. We classified children according to their Val158Met polymorphism: Val/Val, Val/Met, Met/Met. Pressure pain thresholds (PPT) were bilaterally assessed over the temporalis, upper trapezius, second metacarpal, and tibialis anterior muscles. The distribution of Val158Met genotypes was not significantly different (p = 0.335), between children with CTTH and healthy children, and between boys and girls (p = 0.872). Children with CTTH with the Met/Met genotype showed a longer headache history compared with those with Met/Val (p = 0.001) or Val/Val (p = 0.002) genotype. Children with CTTH with Met/Met genotype showed lower PPT over upper trapezius and temporalis muscles than children with CTTH with Met/Val or Val/Val genotype (p < 0.01). The Val158Met catechol-O-methyltransferase (COMT) polymorphism does not appear to be involved in predisposition to suffer from CTTH in children; nevertheless, this genetic factor may be involved in the phenotypic expression, as pressure hypersensitivity was greater in those CTTH children with the Met/Met genotype.

  17. Simultaneous determination of hydroquinone, catechol and resorcinol by voltammetry using graphene screen-printed electrodes and partial least squares calibration.

    Science.gov (United States)

    Aragó, Miriam; Ariño, Cristina; Dago, Àngela; Díaz-Cruz, José Manuel; Esteban, Miquel

    2016-11-01

    Catechol (CC), resorcinol (RC) and hydroquinone (HQ) are dihydroxybenzene isomers that usually coexist in different samples and can be determined using voltammetric techniques taking profit of their fast response, high sensitivity and selectivity, cheap instrumentation, simple and timesaving operation modes. However, a strong overlapping of CC and HQ signals is observed hindering their accurate analysis. In the present work, the combination of differential pulse voltammetry with graphene screen-printed electrodes (allowing detection limits of 2.7, 1.7 and 2.4µmolL(-1) for HQ, CC and RC respectively) and the data analysis by partial least squares calibration (giving root mean square errors of prediction, RMSEP values, of 2.6, 4.1 and 2.3 for HQ, CC and RC respectively) has been proposed as a powerful tool for the quantification of mixtures of these dihydroxybenzene isomers. The commercial availability of the screen-printed devices and the low cost and simplicity of the analysis suggest that the proposed method can be a valuable alternative to chromatographic and electrophoretic methods for the considered species. The method has been applied to the analysis of these isomers in spiked tap water.

  18. Association between cerebrospinal fluid dopamine concentrations and catechol-O-methyltransferase gene polymorphisms in forensic autopsy cases of methamphetamine abusers.

    Science.gov (United States)

    Matsusue, Aya; Ishikawa, Takaki; Michiue, Tomomi; Waters, Brian; Hara, Kenji; Kashiwagi, Masayuki; Takayama, Mio; Ikematsu, Natsuki; Kubo, Shin-Ichi

    2017-01-01

    Methamphetamine (MA) is an illicit psychostimulant that stimulates the release of catecholamines from sympathetic nerve terminals and is widely abused worldwide. Since catechol-O-methyltransferase (COMT) metabolizes catecholamines and mediates adrenergic, noradrenergic, and dopaminergic signaling responses, we investigated the effects of the COMT polymorphisms rs4633 and rs4680 on cerebrospinal fluid (CSF) catecholamine concentrations in autopsies of subjects who died of drug intoxication. 28 MA abusers and 22 fatal psychotropic drug intoxication cases were evaluated. No correlations were identified between rs4633 or rs4680 polymorphisms and CSF concentrations of adrenaline (Adr), noradrenaline (Nad), or dopamine (DA) in fatal psychotropic cases. However, among MA abusers, DA concentrations in the CSF were significantly higher in those with the T allele (CT and TT) of rs4633 than in CC genotype carriers (p=0.004). Moreover, among MA abusers, DA concentrations were significantly higher in those with the A allele (GA and AA) of rs4680 than in GG genotype carriers (p=0.017). In subsequent haplotype analyses of MA abusers, a strong correlation was identified between two COMT haplotypes and CSF DA concentrations (p=0.002). However, the CSF concentrations of Adr and Nad were not associated with COMT genotypes or haplotypes. The present results indicate that rs4633 and rs4680 polymorphisms influence CSF DA concentrations and MA toxicity in MA abusers.

  19. Catechol-O-Methyltransferase (COMT Val108/158 Met polymorphism does not modulate executive function in children with ADHD

    Directory of Open Access Journals (Sweden)

    Stepanian Marina

    2004-12-01

    Full Text Available Abstract Background An association has been observed between the catechol-O-methyltransferase (COMT gene, the predominant means of catecholamine catabolism within the prefrontal cortex (PFC, and neuropsychological task performance in healthy and schizophrenic adults. Since several of the cognitive functions typically deficient in children with Attention Deficit Hyperactivity Disorder (ADHD are mediated by prefrontal dopamine (DA mechanisms, we investigated the relationship between a functional polymorphism of the COMT gene and neuropsychological task performance in these children. Methods The Val108/158 Met polymorphism of the COMT gene was genotyped in 118 children with ADHD (DSM-IV. The Wisconsin Card Sorting Test (WCST, Tower of London (TOL, and Self-Ordered Pointing Task (SOPT were employed to evaluate executive functions. Neuropsychological task performance was compared across genotype groups using analysis of variance. Results ADHD children with the Val/Val, Val/Met and Met/Met genotypes were similar with regard to demographic and clinical characteristics. No genotype effects were observed for WCST standardized perseverative error scores [F2,97 = 0.67; p > 0.05], TOL standardized scores [F2,99 = 0.97; p > 0.05], and SOPT error scores [F2,108 = 0.62; p > 0.05]. Conclusions Contrary to the observed association between WCST performance and the Val108/158 Met polymorphism of the COMT gene in both healthy and schizophrenic adults, this polymorphism does not appear to modulate executive functions in children with ADHD.

  20. Graphene-like carbon nanosheets as a new electrode material for electrochemical determination of hydroquinone and catechol.

    Science.gov (United States)

    Jiang, Hongmei; Wang, Shuqin; Deng, Wenfang; Zhang, Youming; Tan, Yueming; Xie, Qingji; Ma, Ming

    2017-03-01

    We report here graphene-like carbon nanosheets (GCN) as a new electrode material for the electrochemical determination of hydroquinone (HQ) and catechol (CC). The GCN were prepared from maltose using ammonia chloride as a blowing agent and cobalt nitrate as a graphitization catalyst precursor. The as-prepared GCN material shows high graphitization degree, abundant porosity, and large specific surface area. Two well-separated anodic peaks for HQ and CC are obtained at GCN modified glassy carbon electrode (GCE) with a peak-to-peak separation of 118mV. The redox peak currents of HQ and CC at GCN/GCE were much higher than those at bare GCE and reduced graphene oxide modified GCE. For differential pulse voltammetric detection of HQ and CC, the GCN/GCE shows linear response ranges of 1×10(-7) ̶ 3×10(-5)M for HQ and 5×10(-7) ̶ 5×10(-5)M for CC, with detection limits of 2×10(-8)M for HQ, and 5×10(-8) M for CC. Satisfactory recoveries were achieved for the determination of HQ and CC in real water samples.

  1. Association between the Catechol O-methyltransferase (COMT Val158met polymorphism and different dimensions of impulsivity.

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    Leandro Fernandes Malloy-Diniz

    Full Text Available BACKGROUND: Impulsivity is a multidimensional construct which has been associated with dopaminergic neurotransmission. Nonetheless, until this moment, few studies addressed the relationship between different types of impulsivity and the single nucleotide polymorphism caused by a substitution of valine (val with methionine (met in the 158 codon of the Catechol-o-Methyltransferase gene (COMT-val158met. The present study aimed to investigate the association between val158met COMT polymorphism and impulsive behavior measured by two neuropsychological tests. METHODOLOGY/PRINCIPAL FINDINGS: We administered two neuropsychological tests, a Continuous Performance Task and the Iowa Gambling Task were applied to 195 healthy participants to characterize their levels of motor, attentional and non-planning impulsivity. Then, subjects were grouped by genotype, and their scores on impulsivity measures were compared. There were no significant differences between group scores on attentional and motor impulsivity. Those participants who were homozygous for the met allele performed worse in the Iowa Gambling Task than val/val and val/met subjects. CONCLUSIONS/SIGNIFICANCE: Our results suggest that met allele of val158met COMT polymorphism is associated with poor performance in decision-making/cognitive impulsivity task. The results reinforce the hypothesis that val and met alleles of the val158met polymorphism show functional dissociation and are related to different prefrontal processes.

  2. One pot electrochemical synthesis of poly(melamine) entrapped gold nanoparticles composite for sensitive and low level detection of catechol.

    Science.gov (United States)

    Palanisamy, Selvakumar; Ramaraj, Sayee Kannan; Chen, Shen-Ming; Chiu, Te-Wei; Velusamy, Vijayalakshmi; Yang, Thomas C K; Chen, Tse-Wei; Selvam, Sonadevi

    2016-12-29

    A simple and cost effective synthesis of nanomaterials with advanced physical and chemical properties have received much attention to the researchers, and is of interest to the researchers from different disciplines. In the present work, we report a simple and one pot electrochemical synthesis of poly(melamine) entrapped gold nanoparticles (PM-AuNPs) composite. The PM-AuNPs composite was prepared by a single step electrochemical method, wherein the AuNPs and PM were simultaneously fabricated on the electrode surface. The as-prepared materials were characterized by various physicochemical methods. The PM-AuNPs composite modified electrode was used as an electrocatalyst for oxidation of catechol (CC) due to its well-defined redox behavior and enhanced electro-oxidation ability towards CC than other modified electrodes. Under optimized conditions, the differential pulse voltammetry (DPV) was used for the determination of CC. The DPV response of CC was linear over the concentration ranging from 0.5 to 175.5μM with a detection limit of 0.011μM. The PM-AuNPs composite modified electrode exhibits the high selectivity in the presence of range of potentially interfering compounds including dihydroxybenzene isomers. The sensor shows excellent practicality in CC containing water samples, which reveals the potential ability of PM-AuNPs composite modified electrode towards the determination of CC in real samples.

  3. Catechol-O-methyltransferase (COMT) Genotype Affects Age-Related Changes in Plasticity in Working Memory: A Pilot Study

    Science.gov (United States)

    Riemer, Thomas G.; Schulte, Stefanie; Onken, Johanna; Heinz, Andreas; Rapp, Michael A.

    2014-01-01

    Objectives. Recent work suggests that a genetic variation associated with increased dopamine metabolism in the prefrontal cortex (catechol-O-methyltransferase Val158Met; COMT) amplifies age-related changes in working memory performance. Research on younger adults indicates that the influence of dopamine-related genetic polymorphisms on working memory performance increases when testing the cognitive limits through training. To date, this has not been studied in older adults. Method. Here we investigate the effect of COMT genotype on plasticity in working memory in a sample of 14 younger (aged 24–30 years) and 25 older (aged 60–75 years) healthy adults. Participants underwent adaptive training in the n-back working memory task over 12 sessions under increasing difficulty conditions. Results. Both younger and older adults exhibited sizeable behavioral plasticity through training (P < .001), which was larger in younger as compared to older adults (P < .001). Age-related differences were qualified by an interaction with COMT genotype (P < .001), and this interaction was due to decreased behavioral plasticity in older adults carrying the Val/Val genotype, while there was no effect of genotype in younger adults. Discussion. Our findings indicate that age-related changes in plasticity in working memory are critically affected by genetic variation in prefrontal dopamine metabolism. PMID:24772423

  4. How Large Should the QM Region Be in QM/MM Calculations? The Case of Catechol O-Methyltransferase.

    Science.gov (United States)

    Kulik, Heather J; Zhang, Jianyu; Klinman, Judith P; Martínez, Todd J

    2016-11-10

    Hybrid quantum mechanical-molecular mechanical (QM/MM) simulations are widely used in studies of enzymatic catalysis. Until recently, it has been cost prohibitive to determine the asymptotic limit of key energetic and structural properties with respect to increasingly large QM regions. Leveraging recent advances in electronic structure efficiency and accuracy, we investigate catalytic properties in catechol O-methyltransferase, a prototypical methyltransferase critical to human health. Using QM regions ranging in size from reactants-only (64 atoms) to nearly one-third of the entire protein (940 atoms), we show that properties such as the activation energy approach within chemical accuracy of the large-QM asymptotic limits rather slowly, requiring approximately 500-600 atoms if the QM residues are chosen simply by distance from the substrate. This slow approach to asymptotic limit is due to charge transfer from protein residues to the reacting substrates. Our large QM/MM calculations enable identification of charge separation for fragments in the transition state as a key component of enzymatic methyl transfer rate enhancement. We introduce charge shift analysis that reveals the minimum number of protein residues (approximately 11-16 residues or 200-300 atoms for COMT) needed for quantitative agreement with large-QM simulations. The identified residues are not those that would be typically selected using criteria such as chemical intuition or proximity. These results provide a recipe for a more careful determination of QM region sizes in future QM/MM studies of enzymes.

  5. Association between the Catechol-O-Methyltransferase (COMT) Val158Met Polymorphism and Manual Aiming Control in Healthy Subjects

    Science.gov (United States)

    Lage, Guilherme M.; Miranda, Débora M.; Romano-Silva, Marco A.; Campos, Simone B.; Albuquerque, Maicon R.; Corrêa, Humberto; Malloy-Diniz, Leandro F.

    2014-01-01

    Background Prefrontal dopamine is catabolized by the catechol-O-methyltransferase (COMT) enzyme. Current evidence suggests that the val/met single nucleotide polymorphism in the COMT gene can predict the efficiency of executive cognition in humans. Individuals carrying the val allele perform more poorly because less synaptic dopamine is available. Methodology/Principal Findings We investigated the influence of the COMT polymorphism on motor performance in a task that requires different executive functions. We administered a manual aiming motor task that was performed under four different conditions of execution by 111 healthy participants. Participants were grouped according to genotype (met/met, met/val, val/val), and the motor performance among groups was compared. Overall, the results indicate that met/met carriers presented lower levels of peak velocity during the movement trajectory than the val carriers, but met/met carriers displayed higher accuracy than the val carriers. Conclusions/Significance This study found a significant association between the COMT polymorphism and manual aiming control. Few studies have investigated the genetics of motor control, and these findings indicate that individual differences in motor control require further investigation using genetic studies. PMID:24956262

  6. Expression, Purification and Activity Assay of the Recombinant Protein of Catechol-O-Methyltransferase from Chinese White Shrimp (Fenneropenaeus chinensis

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    Dian-Xiang Li

    2010-01-01

    Full Text Available Problem statement: We have previously cloned a gene of Chinese white shrimp Catechol O-Methyltransferase (designated Fc-COMT and characterized the gene expression pattern. In this study, expression and purification as well as activity assay of the recombinant Fc-COMT was further conducted. Approach: Using pET-30a (+ as a prokaryotic expression vector, the recombinant Fc- COMT was expressed in the supernatant of Escherichia coli lysate and easily purified by His-Bind resin chromatography. SDS-PAGE analysis showed that the molecular mass of recombinant Fc-COMT was approximately 30,000 Da, in good agreement with the software-predicted molecular weight. The enzymatic activity of recombinant Fc-COMT was tested using Dihydroxybenzoic Acid (DHBAc as a substrate. Results: The methyl products of DHBAc, Vanillic Acid (VA and Isovanillic Acid (IVA, were detected in the enzymatic reaction mixture with recombinant Fc-COMT by High Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS. Conclusion: The recombinant Fc-COMT has catalytic activity of transferring methyl group from S-Adenosyl-L-Methionine (SAM to the 3’ hydroxyl or 4’ hydroxyl group of benzyl ring of DHBAc.

  7. Catechol-O-methyltransferase Val158met Polymorphism Interacts With Early Experience to Predict Executive Functions in Early Childhood

    Science.gov (United States)

    Blair, Clancy; Sulik, Michael; Willoughby, Michael; Mills-Koonce, Roger; Petrill, Stephen; Bartlett, Christopher; Greenberg, Mark

    2017-01-01

    Numerous studies demonstrate that the Methionine variant of the catechol-O-methyltransferase Val158Met polymorphism, which confers less efficient catabolism of catecholamines, is associated with increased focal activation of prefrontal cortex (PFC) and higher levels of executive function abilities. By and large, however, studies of COMT Val158Met have been conducted with adult samples and do not account for the context in which development is occurring. Effects of early adversity on stress response physiology and the inverted U shape relating catecholamine levels to neural activity in PFC indicate the need to take into account early experience when considering relations between genes such as COMT and executive cognitive ability. Consistent with this neurobiology, we find in a prospective longitudinal sample of children and families (N=1292) that COMT Val158Met interacts with early experience to predict executive function abilities in early childhood. Specifically, the Valine variant of the COMT Val158Met polymorphism, which confers more rather than less efficient catabolism of catecholamines is associated with higher executive function abilities at child ages 48 and 60 months and with faster growth of executive function for children experiencing early adversity, as indexed by cumulative risk factors in the home at child ages 7, 15, 24, and 36 months. Findings indicate the importance of the early environment for the relation between catecholamine genes and developmental outcomes and demonstrate that the genetic moderation of environmental risk is detectable in early childhood. PMID:26251232

  8. Association study between the rs165599 catechol-O-methyltransferase genetic polymorphism and schizophrenia in a Brazilian sample

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    Quirino Cordeiro

    2012-12-01

    Full Text Available Schizophrenia is a severe psychiatric disorder with frequent recurrent psychotic relapses and progressive functional impairment. It results from a poorly understood gene-environment interaction. The gene encoding catechol-O-methyltransferase (COMT is a likely candidate for schizophrenia. Its rs165599 (A/G polymorphism has been shown to be associated with alteration of COMT gene expression. Therefore, the present study aimed to investigate a possible association between schizophrenia and this polymorphism. The distribution of the alleles and genotypes of this polymorphism was investigated in a Brazilian sample of 245 patients and 834 controls. The genotypic frequencies were in Hardy-Weinberg equilibrium and no statistically significant differences were found between cases and controls when analyzed according to gender or schizophrenia subtypes. There was also no difference in homozygosis between cases and controls. Thus, in the sample studied, there was no evidence of any association between schizophrenia and rs165599 (A/G polymorphism in the non-coding region 3' of the COMT gene.

  9. Self-healable mussel-mimetic nanocomposite hydrogel based on catechol-containing polyaspartamide and graphene oxide.

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    Wang, Bo; Jeon, Young Sil; Park, Ho Seok; Kim, Ji-Heung

    2016-12-01

    Stimuli-responsive and self-healing materials have a wide range of potential uses, and some significant research has focused on cross-linking of hydrogel materials by means of reversible coordination bonding. The resulting materials, however, tend to have poor mechanical properties with pronounced weakness and brittleness. In this work, we present a novel mussel-inspired graphene oxide(GO)-containing hydrogel based on modified polyaspartamide with γ-amino butyric acid (GABA), 3.4-dihydroxyphenethylamine (DOPA), and ethanolamine (EA), termed PolyAspAm(GABA/DOPA/EA). Here both GO nanosheets and boric acid (H3BO3) act as cross-linkers, interacting with polar functional groups of the PolyAspAm(GABA/DOPA/EA). Compared to PolyAspAm(GABA/DOPA/EA)/B(3+) gel without GO, the same containing 5wt% of GO yielded a 10-fold increase in both the storage and loss moduli, as well as 134% and 104% increases in the tensile and compressive strengths, respectively. In addition, the GO-containing polyaspartamide hydrogel exhibited rapid and autonomous self-healing property. Two types of bonding, boron-catechol coordination and strong hydrogen bonding interactions between PolyAspAm side chains and GO nanosheets, would impart the enhanced mechanical strength and good reversible gelation behavior upon pH stimulation to the hydrogel, making this biocompatible hydrogel a promising soft matter for biomedical applications.

  10. The catechol-O-methyltransferase inhibitor, tolcapone, increases the bioavailability of unmethylated (−)-epigallocatechin-3-gallate in mice*

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    Forester, Sarah C.; Lambert, Joshua D.

    2015-01-01

    (−)-Epigallocatechin-3-gallate (EGCG), has been shown to inhibit cancer in vivo. EGCG, however, is rapidly methylated by catechol-O-methyl transferase (COMT), which reduces its cancer preventive efficacy. Tolcapone (TOL), is a clinically-used COMT inhibitor. Here, we examined the effect of TOL on the bioavailability of EGCG in male CF-1 mice. Plasma and tissue levels of EGCG and its methyl metabolites were determined following intragastric administration of EGCG (100 mg/kg), TOL (30 mg/kg), or the combination. In mice treated with EGCG, unmethylated plasma EGCG accounted for 63.4 % of the total. Co-administration of TOL increased this fraction to 87.9 %. In the urine, unmethylated EGCG accounted for 29.2 % of the total, whereas treatment with EGCG plus TOL increased this to 81.8 %. Similar effects were observed in the major organs examined. TOL effectively inhibited the methylation of EGCG in vivo. Future studies should examine the cancer preventive effects of the combination. PMID:26213577

  11. Race Moderates the Association of Catechol-O-methyltransferase Genotype and Posttraumatic Stress Disorder in Preschool Children

    Science.gov (United States)

    Humphreys, Kathryn L.; Scheeringa, Michael S.

    2014-01-01

    Abstract Objective: The present study sought to replicate previous findings of an association between the Catechol-O-methyltransferase (COMT) val158met polymorphism with posttraumatic stress disorder (PTSD) and symptomatology in a novel age group, preschool children. Methods: COMT genotype was determined in a sample of 171 3–6-year-old trauma-exposed children. PTSD was assessed with a semistructured interview. Accounting for sex, trauma type, and age, genotype was examined in relation to categorical and continuous measures of PTSD both controlling for race and within the two largest racial categories (African American [AA] and European American [EA]). Results: Race significantly moderated the association between genotype and PTSD. Specifically, the genotype associated with increased PTSD symptoms in one racial group had the opposite association in the other racial group. For AA children the met/met genotype was associated with more PTSD symptoms. However, for EA children, val allele carriers had more PTSD symptoms. Whereas every AA child with the met/met genotype met criteria for PTSD, none of the EA children with the met/met genotype did. This genetic association with COMT genotype, in both races but in opposite directions, was most associated with increased arousal symptoms. Conclusions: These findings replicate previous findings in participants of African descent, highlight the moderating effect of race on the association between COMT genotype and PTSD, and provide direct evidence that consideration of population stratification within gene-by-environment studies is valuable to prevent false negative findings. PMID:25329975

  12. Iron Oxide Surface Chemistry: The Effect of Chemical Structure on Binding in Benzoic Acid and Catechol Derivatives.

    Science.gov (United States)

    Korpany, Katalin V; Majewski, Dorothy D; Chiu, Cindy T; Cross, Shoronia N; Blum, Amy Szuchmacher

    2017-02-18

    Excellent performance of functionalized iron oxide nanoparticles in nanomaterial and biomedical applications often relies on achieving attachment of ligands to the iron oxide surface both in sufficient number and with proper orientation. Towards this end, we determine relationships between ligand chemical structure and surface binding on magnetic iron oxide nanoparticles for a series of related benzoic acid and catechol derivatives. Ligand exchange was used to introduce the model ligands, and the resulting nanoparticles were characterized by FTIR-ATR, transmission electron microscopy (TEM), and nanoparticle solubility behavior. An in-depth analysis of ligand electronic effects and reaction conditions reveals that the nature of ligand binding does not solely depend on the presence of functional groups known to bind to iron oxide nanoparticles. The structure of the resulting ligand-surface complex was primarily influenced by the relative positioning of hydroxyl and carboxylic acid groups within the ligand as well as whether or not HCl(aq) was added to the ligand exchange reaction. Overall, this study will help guide future ligand design and ligand exchange strategies towards realizing truly custom-built iron oxide nanoparticles.

  13. Metabolic Disposition of Luteolin Is Mediated by the Interplay of UDP-Glucuronosyltransferases and Catechol-O-Methyltransferases in Rats.

    Science.gov (United States)

    Wang, Liping; Chen, Qingwei; Zhu, Lijun; Li, Qiang; Zeng, Xuejun; Lu, Linlin; Hu, Ming; Wang, Xinchun; Liu, Zhongqiu

    2017-03-01

    Luteolin partially exerts its biologic effects via its metabolites catalyzed by UDP-glucuronosyltransferases (UGTs) and catechol-O-methyltransferases (COMTs). However, the interplay of UGTs and COMTs in mediating luteolin disposition has not been well clarified. In this study, we investigated the glucuronidation and methylation pathways of luteolin mediated by the interplay of UGTs and COMTs in vivo and in vitro. A total of nine luteolin metabolites was detected in rat plasma and bile by liquid chromatography-tandem mass spectrometry, namely, three glucuronides, two methylated metabolites, and four methylated glucuronides. Luteolin-3'-glucuronide (Lut-3'-G) exhibited the highest systemic exposure among these metabolites. Kinetics studies in rat liver S9 fractions suggested two pathways, as follows: 1) Luteolin was glucuronidated to luteolin-7-glucuronide, luteolin-4'-glucuronide, and Lut-3'-G by UGTs, and then Lut-7-G was methylated to chrysoeriol-7-glucuronide and diosmetin-7-glucuronide by COMTs. 2) Alternatively, luteolin was methylated to chrysoeriol and diosmetin by COMTs, and then chrysoeriol and diosmetin were glucuronidated by UGTs to their respective glucuronides. The methylation rate of luteolin was significantly increased by the absence of glucuronidation, whereas the glucuronidation rate was increased by the absence of methylation, but to a lesser extent. In conclusion, two pathways mediated by the interplay of UGTs and COMTs are probably involved in the metabolic disposition of luteolin. The glucuronidation and methylation of luteolin compensate for each other, although glucuronidation is the predominant pathway.

  14. Impedance spectroscopy study of a catechol-modified activated carbon electrode as active material in electrochemical capacitor

    Science.gov (United States)

    Cougnon, C.; Lebègue, E.; Pognon, G.

    2015-01-01

    Modified activated carbon (Norit S-50) electrodes with electrochemical double layer (EDL) capacitance and redox capacitance contributions to the electric charge storage were tested in 1 M H2SO4 to quantify the benefit and the limitation of the surface redox reactions on the electrochemical performances of the resulting pseudo-capacitive materials. The electrochemical performances of an electrochemically anodized carbon electrode and a catechol-modified carbon electrode, which make use both EDL capacitance of the porous structure of the carbon and redox capacitance, were compared to the performances obtained for the pristine carbon. Nitrogen gas adsorption measurements have been used for studying the impact of the grafting on the BET surface area, pore size distribution, pore volume and average pore diameter. The electrochemical behavior of carbon materials was studied by cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The EIS data were discussed by using a complex capacitance model that allows defining the characteristic time constant, the global capacitance and the frequency at which the maximum charge stored is reached. The EIS measurements were achieved at different dc potential values where a redox activity occurs and the evolution of the capacitance and the capacitive relaxation time with the electrode potential are presented. Realistic galvanostatic charge/discharge measurements performed at different current rates corroborate the results obtained by impedance.

  15. Membrane-bound catechol-O-methyl transferase in cortical neurons and glial cells is intracellularly oriented

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    Björn H Schott

    2010-10-01

    Full Text Available Catechol-O-methyl transferase (COMT is involved in the inactivation of dopamine in brain regions in which the dopamine transporter (DAT1 is sparsely expressed. The membrane-bound isoform of COMT (MB-COMT is the predominantly expressed form in the mammalian central nervous system (CNS. It has been a matter of debate whether in neural cells of the CNS the enzymatic domain of MB-COMT is oriented towards the cytoplasmic or the extracellular compartment. Here we used live immunocytochemistry on cultured neocortical neurons and glial cells to investigate the expression and membrane orientation of native COMT and of transfected MB-COMT fused to green fluorescent protein (GFP. After live staining, COMT immunoreactivity was reliably detected in both neurons and glial cells after permeabilization, but not on unpermeabilized cells. Similarly, autofluorescence of COMT-GFP fusion protein and antibody fluorescence showed overlap only in permeabilized neurons. Our data provide converging evidence for an intracellular membrane orientation of MB-COMT in neurons and glial cells, suggesting the presence of a DAT1-independent postsynaptic uptake mechanism for dopamine, prior to its degradation via COMT.

  16. Catechol-O-methyltransferase (COMT Genotype Affects Age-Related Changes in Plasticity in Working Memory: A Pilot Study

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    Stephan Heinzel

    2014-01-01

    Full Text Available Objectives. Recent work suggests that a genetic variation associated with increased dopamine metabolism in the prefrontal cortex (catechol-O-methyltransferase Val158Met; COMT amplifies age-related changes in working memory performance. Research on younger adults indicates that the influence of dopamine-related genetic polymorphisms on working memory performance increases when testing the cognitive limits through training. To date, this has not been studied in older adults. Method. Here we investigate the effect of COMT genotype on plasticity in working memory in a sample of 14 younger (aged 24–30 years and 25 older (aged 60–75 years healthy adults. Participants underwent adaptive training in the n-back working memory task over 12 sessions under increasing difficulty conditions. Results. Both younger and older adults exhibited sizeable behavioral plasticity through training (P<.001, which was larger in younger as compared to older adults (P<.001. Age-related differences were qualified by an interaction with COMT genotype (P<.001, and this interaction was due to decreased behavioral plasticity in older adults carrying the Val/Val genotype, while there was no effect of genotype in younger adults. Discussion. Our findings indicate that age-related changes in plasticity in working memory are critically affected by genetic variation in prefrontal dopamine metabolism.

  17. The effect of GSM and TETRA mobile handset signals on blood pressure, catechol levels and heart rate variability.

    Science.gov (United States)

    Barker, Anthony T; Jackson, Peter R; Parry, Helen; Coulton, Leslie A; Cook, Greg G; Wood, Steven M

    2007-09-01

    An acute rise in blood pressure has been reported in normal volunteers during exposure to signals from a mobile phone handset. To investigate this finding further we carried out a double blind study in 120 healthy volunteers (43 men, 77 women) in whom we measured mean arterial pressure (MAP) during each of six exposure sessions. At each session subjects were exposed to one of six different radio frequency signals simulating both GSM and TETRA handsets in different transmission modes. Blood catechols before and after exposure, heart rate variability during exposure, and post exposure 24 h ambulatory blood pressure were also studied. Despite having the power to detect changes in MAP of less than 1 mmHg none of our measurements showed any effect which we could attribute to radio frequency exposure. We found a single statistically significant decrease of 0.7 mmHg (95% CI 0.3-1.2 mmHg, P = .04) with exposure to GSM handsets in sham mode. This may be due to a slight increase in operating temperature of the handsets when in this mode. Hence our results have not confirmed the original findings of an acute rise in blood pressure due to exposure to mobile phone handset signals. In light of this negative finding from a large study, coupled with two smaller GSM studies which have also proved negative, we are of the view that further studies of acute changes in blood pressure due to GSM and TETRA handsets are not required.

  18. Association between the catechol-o-methyltransferase val158met polymorphism with susceptibility and severity of carpal tunnel syndrome

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    Erkol İnal E

    2015-12-01

    Full Text Available Carpal tunnel syndrome (CTS is the most common entrapment neuropathy of the upper extremity. In this study, we aimed to clarify the relationships between the catechol-O-methyltransferase (COMT gene Val158Met (rs4680 polymorphism and development, functional and clinical status of CTS. Ninety-five women with electro diagnostically confirmed CTS and 95 healthy controls were enrolled in the study. The functional and clinical status of the patients was measured by the Turkish version of the Boston Questionnaire and intensity of pain related to the past 2 weeks was evaluated on a visual analog scale (VAS. The Val158Met polymorphism was determined using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP, method. We divided patients according to the genotypes of the Val158Met polymorphism as Val/Val, Val/Met and Met/Met. There were not any significant differences in terms of Val158Met polymorphisms between patients and healthy controls (p >0.05. We also did not find any relationships between the Val158Met polymorphism and CTS (p >0.05. In conclusion, although we did not find any relationships between CTS and the Val158Met polymorphism, we could not generalize this result to the general population. Future studies are warranted to conclude precise associations.

  19. Iron binding efficiency of polyphenols: Comparison of effect of ascorbic acid and ethylenediaminetetraacetic acid on catechol and galloyl groups.

    Science.gov (United States)

    Tamilmani, Poonkodi; Pandey, Mohan Chandra

    2016-04-15

    Dietary polyphenols are markedly studied for their antioxidant activity. They also have a negative impact on nutrition whereby they interfere with iron absorption. Common dietary polyphenols include: catechins, flavonols, flavanols, flavones, anthocyanins, proanthocyanidins and phenolic acids. Ascorbic acid (AA) and Ethylenediaminetetraacetic acid (EDTA) are commonly used to counter act this reaction and increase iron bioavailability. This study was aimed at determining the effect of AA and EDTA on the catechol or galloyl iron binding ability of pure phenolics, coffee and tea. Phenolic concentrations of 40, 80, 610, 240, 320, 400, 520 and 900 μg/ml were tested against six levels of AA and EDTA. These effects were studied in detail using Multivariate Analysis of Variance (MANOVA) with the hypothesis that there would be one or more mean differences between the ratio of enhancer and the different concentrations of samples tested. AA was found to be more efficient than EDTA in a way that lesser quantity is required for completely overcoming negative iron binding effects of polyphenols and similar samples.

  20. 1,2-环己二醇气相催化脱氢制备邻苯二酚的研究%Synthesis of Catechol by Gaseous Catalytic Dehydrogenation of 1,2-Cyclohexanediol

    Institute of Scientific and Technical Information of China (English)

    熊前政; 刘智凌; 陈明; 李玉明; 廖文文; 任伟

    2001-01-01

    探讨了由1,2-环己二醇气相催化脱氢制备邻苯二酚的工艺过程,采用Pd/活性炭为催化剂,在催化剂负荷为0.3 g环己二醇/(g催化剂*h),反应温度300 ℃条件下,环己二醇转化率>90%,邻苯二酚选择性>85%。产物采用溶剂萃取,产品含量w(邻苯二酚)≥99%。%The process of catechol synthesis by gaseous catalytic dehydrogenation of 1,2-cyclohexanediol was researched.Convervion of 1,2-cyclohexandiol and selectivity for catechol were over 90% and 85% respectively.Purity of catechol was over 99% by solvent extraction.

  1. The Role of Human Aldo-Keto Reductases (AKRs in the Metabolic Activation and Detoxication of Polycyclic Aromatic Hydrocarbons: Interconversion of PAH-catechols and PAH o-Quinones

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    Li eZhang

    2012-11-01

    Full Text Available Polycyclic aromatic hydrocarbons (PAH are ubiquitous environmental pollutants. They are procarcinogens requiring metabolic activation to elicit their deleterious effects. Aldo-keto reductases (AKR catalyze the oxidation of proximate carcinogenic PAH trans-dihydrodiols to yield electrophilic and redox-active PAH o-quiniones. AKRs are also found to be capable of reducing PAH o-quinones to form PAH catechols. The interconversion of o-quinones and catechols results in the redox cycling of PAH o-quinones to give rise to the generation of reactive oxygen species and subsequent oxidative DNA damage. On the other hand, PAH catechols can be intercepted through phase II metabolism by which PAH o-quinones could be detoxified and eliminated. The aim of the present review is to summarize the role of human AKRs in the metabolic activation/detoxication of PAH and the relevance of phase II conjugation reactions to human lung carcinogenesis.

  2. Recovery of (/sup 3/H)noradrenaline from different metabolic compartments of rat brain with respect to the role of catechol-O-methyltransferase

    Energy Technology Data Exchange (ETDEWEB)

    Koester, G.; Goede, E.; Breuer, H.

    1984-03-01

    Rats were treated with reserpine, desmethyl-imipramine, or carrier, either alone or in combination with tropolone. Either 10 min (t1) or 1 h (t2) after intraventricular injection of (/sup 3/H)noradrenaline, they were decapitated. The total /sup 3/H activity and the recovery of (/sup 3/H)noradrenaline were determined in tissue extracts from various brain regions. Maximum total /sup 3/H activity was measured at t1 in all tropolone-treated rats; the mean sum of these results served as an estimate of the initial tissue concentration of (/sup 3/H)noradrenaline. At t1, 40-50% of the sum of (/sup 3/H)noradrenaline and its metabolites was recovered unchanged in normal rats; reserpine and DMI reduced the recovery to 18-27%. In all groups, the decline of (/sup 3/H)noradrenaline was retarded after t1. Inhibition of catechol-O-methyltransferase by tropolone caused consistently elevated (/sup 3/H)noradrenaline levels, but did not affect the metabolic rate after t1 when compared with similarly pretreated, but tropolone-free rats. Thus, if catechol-O-methyltransferase was inhibited during the injection of (/sup 3/H)noradrenaline, a higher percentage of the amine had been taken up into spaces with a slow noradrenaline turnover. The maximum increase was seen when the neuronal uptake1 was inhibited by desmethylimipramine. This supported the hypothesis that an additional extraneuronal space exists, in addition to the known intraneuronal and extraneuronal compartments, which has a slow noradrenaline turnover. The tropolone effect on the noradrenaline recovery possibly shows that there might be a saturable ''methylating system,'' similar to that described for the periphery, in which catechol-O-methyltransferase is linked to the extraneuronal uptake.

  3. Molybdenum (VI) binded to humic and nitrohumic acid models in aqueous solutions: phthalic, 3- and 4-nitrophthalic acids, catechol and 4-nitrocathecol, part 1

    Energy Technology Data Exchange (ETDEWEB)

    Merce, Ana Lucia R.; Greboge, Cristiane; Mendes, Giovani; Mangrich, Antonio S. [Parana Univ., Curitiba, PR (Brazil). Dept. de Quimica]. E-mail: anamerce@ufpr.br

    2005-02-01

    Many mathematical models have been tested in the literature in the search of how humic acids (HA) from many natural sources complex to metal ions. HA are composed of natural degradation sources of C, N, P and S, bearing hydroxyl and carboxyl aromatic units in their inner structure. The presence of metal ions binded to these basic sites promotes fertility to the soil as well as can hold metal ions to be slowly released as the mineralization of the soil occurs. Nitrohumic substances are a laboratory artifact with higher N content then humic acids with an electron withdrawing group - NO{sub 2}. However they still bear the main HA constituent chemical groups such as salicylate, catecholate and phthalate derivatives, all prone to bind to metal ions depending on the chemical conditions of the environment. This work intended to study the complexing behaviour of some HA models having very different Lewis basic binding sites in the presence of molybdenum (VI) ions, in aqueous systems, with varying pH values using some analytical tools. The formation constants of phthalic acid, 3- and 4-nitrophthalic acids, catechol and 4-nitrocatechol with Mo(VI) as well as the speciation of the complex species according to varying pH values were determined. Potentiometric and cyclic voltammetric titrations were employed to calculate the formation constants and to monitor the formation and decomposition of some complexed species. The results showed that although there is complexation between phthalic derived acids and molybdenum, the speciation favours it only until pH 6.0 at the best. On the other hand, salicylic and catechol derived models showed existence of complexation until basic pH values, allowing a compromising complexation pH range when humic and nitrohumic substances are involved. (author)

  4. The relationship between childhood abuse and dissociation. Is it influenced by catechol-O-methyltransferase (COMT) activity?

    Science.gov (United States)

    Savitz, Jonathan B; van der Merwe, Lize; Newman, Timothy K; Solms, Mark; Stein, Dan J; Ramesar, Rajkumar S

    2008-03-01

    Dissociation is a failure of perceptual, memorial and emotional integration that is associated with a variety of psychiatric disorders. Dissociative processes are usually attributed to the sequelae of childhood trauma although there are data to suggest that genetic influences are also important. Bipolar disorder (BD), a condition with a strong genetic basis, has also been associated with early psychological trauma. Since childhood trauma is a risk factor for both BD and dissociation, we tested for potential gene-childhood abuse interactions on dissociation in a pilot sample of BD probands and their affected and unaffected relatives (n=178). Dissociation was measured with the Dissociative Experiences Scale (DES II) and childhood maltreatment with the Childhood Trauma Questionnaire (CTQ). The BD and recurrent unipolar depression (MDE-R) groups showed higher levels of self-reported abuse and dissociation than their unaffected relatives. The low-activity Met allele of the Val66Met polymorphism of the brain-derived neurotrophic factor (BDNF) gene was associated with lower levels of self-reported dissociation. Further, the functional catechol-O-methyltransferase (COMT) Val158Met polymorphism interacted significantly with total CTQ abuse scores to impact perceived dissociation. The Val/Val genotype was associated with increasing levels of dissociation in participants exposed to higher levels of childhood trauma. The opposite was observed in people with Met/Met genotypes who displayed decreased dissociation with increasing self-reported childhood trauma. The current findings support the involvement of the COMT Val158Met polymorphism in mediating the relationship between trauma and psychopathology.

  5. The influence of the Val158Met catechol-O-methyltransferase polymorphism on the personality traits of bipolar patients.

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    Wendy Dávila

    Full Text Available INTRODUCTION: Certain personality traits and genetic polymorphisms are contributing factors to bipolar disorder and its symptomatology, and in turn, this syndrome influences personality. The aim of the present study is to compare the personality traits of euthymic bipolar patients with healthy controls and to investigate the effect of the catechol-O-methyltransferase (COMT Val158Met genotype on those traits. We recruited thirty seven bipolar I patients in euthymic state following a manic episode and thirty healthy controls and evaluated their personality by means of the Cloninger's Temperament and Character Inventory (version TCI-R-140. We assessed the influence of the polymorphism Val158Met in the COMT gene on the personality of these patients. The patients scored higher than controls in harm avoidance (61.3±12.5 vs. 55.3±8.1 and self-transcendence (45.3±12.8 vs. 32.7±8.2 and scored lower than controls in self-directedness (68.8±13.3 vs. 79.3±8.1, cooperativeness (77.1±9.1 vs. 83.9±6.5 and persistence (60.4±15.1 vs. 67.1±8.9. The novelty seeking dimension associates with the Val158Met COMT genotype; patients with the low catabolic activity genotype, Met/Met, show a higher score than those with the high catabolic activity genotype, Val/Val. CONCLUSIONS: Suffering from bipolar disorder could have an impact on personality. A greater value in harm avoidance may be a genetic marker for a vulnerability to the development of a psychiatric disorder, but not bipolar disorder particularly, while a low value in persistence may characterize affective disorders or a subgroup of bipolar patients. The association between novelty seeking scores and COMT genotype may be linked with the role dopamine plays in the brain's reward circuits.

  6. Catechol-o-methyltransferase expression and 2-methoxyestradiol affect microtubule dynamics and modify steroid receptor signaling in leiomyoma cells.

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    Salama A Salama

    Full Text Available CONTEXT: Development of optimal medicinal treatments of uterine leiomyomas represents a significant challenge. 2-Methoxyestradiol (2ME is an endogenous estrogen metabolite formed by sequential action of CYP450s and catechol-O-methyltransferase (COMT. Our previous study demonstrated that 2ME is a potent antiproliferative, proapoptotic, antiangiogenic, and collagen synthesis inhibitor in human leiomyomas cells (huLM. OBJECTIVES: Our objectives were to investigate whether COMT expression, by the virtue of 2ME formation, affects the growth of huLM, and to explore the cellular and molecular mechanisms whereby COMT expression or treatment with 2ME affect these cells. RESULTS: Our data demonstrated that E(2-induced proliferation was less pronounced in cells over-expressing COMT or treated with 2ME (500 nM. This effect on cell proliferation was associated with microtubules stabilization and diminution of estrogen receptor alpha (ERalpha and progesterone receptor (PR transcriptional activities, due to shifts in their subcellular localization and sequestration in the cytoplasm. In addition, COMT over expression or treatment with 2ME reduced the expression of hypoxia-inducible factor -1alpha (HIF-1 alpha and the basal level as well as TNF-alpha-induced aromatase (CYP19 expression. CONCLUSIONS: COMT over expression or treatment with 2ME stabilize microtubules, ameliorates E(2-induced proliferation, inhibits ERalpha and PR signaling, and reduces HIF-1 alpha and CYP19 expression in human uterine leiomyoma cells. Thus, microtubules are a candidate target for treatment of uterine leiomyomas. In addition, the naturally occurring microtubule-targeting agent 2ME represents a potential new therapeutic for uterine leiomyomas.

  7. Catechol-O-methyltransferase Val158Met polymorphism modulates gray matter volume and functional connectivity of the default mode network.

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    Tian Tian

    Full Text Available The effect of catechol-O-methyltransferase (COMT Val158Met polymorphism on brain structure and function has been previously investigated separately and regionally; this prevents us from obtaining a full picture of the effect of this gene variant. Additionally, gender difference must not be overlooked because estrogen exerts an interfering effect on COMT activity. We examined 323 young healthy Chinese Han subjects and analyzed the gray matter volume (GMV differences between Val/Val individuals and Met carriers in a voxel-wise manner throughout the whole brain. We were interested in genotype effects and genotype × gender interactions. We then extracted these brain regions with GMV differences as seeds to compute resting-state functional connectivity (rsFC with the rest of the brain; we also tested the genotypic differences and gender interactions in the rsFCs. Val/Val individuals showed decreased GMV in the posterior cingulate cortex (PCC compared with Met carriers; decreased GMV in the medial superior frontal gyrus (mSFG was found only in male Val/Val subjects. The rsFC analysis revealed that both the PCC and mSFG were functionally correlated with brain regions of the default mode network (DMN. Both of these regions showed decreased rsFCs with different parts of the frontopolar cortex of the DMN in Val/Val individuals than Met carriers. Our findings suggest that the COMT Val158Met polymorphism modulates both the structure and functional connectivity within the DMN and that gender interactions should be considered in studies of the effect of this genetic variant, especially those involving prefrontal morphology.

  8. Catechol-O-methyltransferase Val158Met polymorphism on the relationship between white matter hyperintensity and cognition in healthy people.

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    Mu-En Liu

    Full Text Available BACKGROUND: White matter lesions can be easily observed on T2-weighted MR images, and are termed white matter hyperintensities (WMH. Their presence may be correlated with cognitive impairment; however, the relationship between regional WMH volume and catechol-O-methyltransferase (COMT Val158Met polymorphism in healthy populations remains unclear. METHODS: We recruited 315 ethnic Chinese adults with a mean age of 54.9 ± 21.8 years (range: 21-89 y to examine the genetic effect of COMT on regional WMH and the manner in which they interact to affect cognitive function in a healthy adult population. Cognitive tests, structural MRI scans, and genotyping of COMT were conducted for each participant. RESULTS: Negative correlations between the Digit Span Forward (DSF score and frontal WMH volumes (r = -.123, P = .032, uncorrected were noted. For the genetic effect of COMT, no significant difference in cognitive performance was observed among 3 genotypic groups. However, differences in WMH volumes over the subcortical region (P = .016, uncorrected, whole brain (P = .047, uncorrected, and a trend over the frontal region (P = .050, uncorrected were observed among 3 COMT genotypic groups. Met homozygotes and Met/Val heterozygotes exhibited larger WMH volumes in these brain regions than the Val homozygotes. Furthermore, a correlation between the DSF and regional WMH volume was observed only in Met homozygotes. The effect size (cohen's f revealed a small effect. CONCLUSIONS: The results indicate that COMT might modulate WMH volumes and the effects of WMH on cognition.

  9. Modulation of catechol estrogen synthesis by rat liver microsomes: effects of treatment with growth hormone or testosterone

    Energy Technology Data Exchange (ETDEWEB)

    Quail, J.A.; Jellinck, P.H.

    1987-09-01

    The ability of GH from various mammalian species, administered to normal mature male rats by constant infusion, to decrease the hepatic 2-hydroxylation of estradiol (E2) to female levels, as measured by the release of /sup 3/H/sub 2/O from (2-3H)E2, was determined. Rat and human GH (hGH) showed the highest activity while ovine GH was inactive. PRL (0.6 IU/h X kg) administered together with hGH (0.02 IU/h X kg) did not antagonize the feminizing action of GH. Infusion of hGH into male rats decreased the affinity of estradiol 2-hydroxylase for its steroid substrate and altered the linear Lineweaver-Burk plot towards a nonlinear hyperbolic plot characteristic of the female. The apparent Michaelis-Menten constant (Km) for the reaction was 1.69 microM for males and 2.75 microM for testosterone-treated ovariectomized females. An equal mixture of liver microsomes from male and female rats gave kinetic values similar to those observed with males alone. Neonatal imprinting with androgen did not alter the magnitude of the response of female rats to treatment with testosterone and/or GH at maturity and the androgen effect could only be shown in ovariectomized animals. The results with rats of different endocrine status were corroborated by the kinetic data and by the pattern of metabolites obtained with (4-/sup 14/C)E2 when examined by TLC and autoradiography. The hormonal control of estradiol 2-hydroxylase, the key enzyme in catechol estrogen formation, and the contribution of sex-specific multiple forms of the enzyme to this reaction are discussed.

  10. Electrochemical behavior of polypyrrol/AuNP composites deposited by different electrochemical methods: sensing properties towards catechol

    Science.gov (United States)

    García-Hernández, Celia; Medina-Plaza, Cristina; Martín-Pedrosa, Fernando; Blanco, Yolanda; de Saja, José Antonio

    2015-01-01

    Summary Two different methods were used to obtain polypyrrole/AuNP (Ppy/AuNP) composites. One through the electrooxidation of the pyrrole monomer in the presence of colloidal gold nanoparticles, referred to as trapping method (T), and the second one by electrodeposition of both components from one solution containing the monomer and a gold salt, referred to as cogeneration method (C). In both cases, electrodeposition was carried out through galvanostatic and potentiostatic methods and using platinum (Pt) or stainless steel (SS) as substrates. Scanning electron microscopy (SEM) demonstrated that in all cases gold nanoparticles of similar size were uniformly dispersed in the Ppy matrix. The amount of AuNPs incorporated in the Ppy films was higher when electropolymerization was carried out by chronopotentiometry (CP). Besides, cogeneration method allowed for the incorporation of a higher number of AuNPs than trapping. Impedance experiments demonstrated that the insertion of AuNPs increased the conductivity. As an electrochemical sensor, the Ppy/AuNp deposited on platinum exhibited a strong electrocatalytic activity towards the oxidation of catechol. The effect was higher in films obtained by CP than in films obtained by chronoamperometry (CA). The influence of the method used to introduce the AuNPs (trapping or cogeneration) was not so important. The limits of detection (LOD) were in the range from 10−5 to 10−6 mol/L. LODs attained using films deposited on platinum were lower due to a synergy between AuNPs and platinum that facilitates the electron transfer, improving the electrocatalytic properties. Such synergistic effects are not so pronounced on stainless steel, but acceptable LOD are attained with lower price sensors. PMID:26665076

  11. Electrochemical behavior of polypyrrol/AuNP composites deposited by different electrochemical methods: sensing properties towards catechol

    Directory of Open Access Journals (Sweden)

    Celia García-Hernández

    2015-10-01

    Full Text Available Two different methods were used to obtain polypyrrole/AuNP (Ppy/AuNP composites. One through the electrooxidation of the pyrrole monomer in the presence of colloidal gold nanoparticles, referred to as trapping method (T, and the second one by electrodeposition of both components from one solution containing the monomer and a gold salt, referred to as cogeneration method (C. In both cases, electrodeposition was carried out through galvanostatic and potentiostatic methods and using platinum (Pt or stainless steel (SS as substrates. Scanning electron microscopy (SEM demonstrated that in all cases gold nanoparticles of similar size were uniformly dispersed in the Ppy matrix. The amount of AuNPs incorporated in the Ppy films was higher when electropolymerization was carried out by chronopotentiometry (CP. Besides, cogeneration method allowed for the incorporation of a higher number of AuNPs than trapping. Impedance experiments demonstrated that the insertion of AuNPs increased the conductivity. As an electrochemical sensor, the Ppy/AuNp deposited on platinum exhibited a strong electrocatalytic activity towards the oxidation of catechol. The effect was higher in films obtained by CP than in films obtained by chronoamperometry (CA. The influence of the method used to introduce the AuNPs (trapping or cogeneration was not so important. The limits of detection (LOD were in the range from 10−5 to 10−6 mol/L. LODs attained using films deposited on platinum were lower due to a synergy between AuNPs and platinum that facilitates the electron transfer, improving the electrocatalytic properties. Such synergistic effects are not so pronounced on stainless steel, but acceptable LOD are attained with lower price sensors.

  12. Catechol-O-Methyltransferase Val158Met Polymorphism on the Relationship between White Matter Hyperintensity and Cognition in Healthy People

    Science.gov (United States)

    Liu, Mu-En; Huang, Chu-Chung; Yang, Albert C.; Tu, Pei-Chi; Yeh, Heng-Liang; Hong, Chen-Jee; Liou, Ying-Jay; Chen, Jin-Fan; Chou, Kun-Hsien; Lin, Ching-Po; Tsai, Shih-Jen

    2014-01-01

    Background White matter lesions can be easily observed on T2-weighted MR images, and are termed white matter hyperintensities (WMH). Their presence may be correlated with cognitive impairment; however, the relationship between regional WMH volume and catechol-O-methyltransferase (COMT) Val158Met polymorphism in healthy populations remains unclear. Methods We recruited 315 ethnic Chinese adults with a mean age of 54.9±21.8 years (range: 21–89 y) to examine the genetic effect of COMT on regional WMH and the manner in which they interact to affect cognitive function in a healthy adult population. Cognitive tests, structural MRI scans, and genotyping of COMT were conducted for each participant. Results Negative correlations between the Digit Span Forward (DSF) score and frontal WMH volumes (r = −.123, P = .032, uncorrected) were noted. For the genetic effect of COMT, no significant difference in cognitive performance was observed among 3 genotypic groups. However, differences in WMH volumes over the subcortical region (P = .016, uncorrected), whole brain (P = .047, uncorrected), and a trend over the frontal region (P = .050, uncorrected) were observed among 3 COMT genotypic groups. Met homozygotes and Met/Val heterozygotes exhibited larger WMH volumes in these brain regions than the Val homozygotes. Furthermore, a correlation between the DSF and regional WMH volume was observed only in Met homozygotes. The effect size (cohen’s f) revealed a small effect. Conclusions The results indicate that COMT might modulate WMH volumes and the effects of WMH on cognition. PMID:24551149

  13. Affect-modulated startle: interactive influence of catechol-O-methyltransferase Val158Met genotype and childhood trauma.

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    Benedikt Klauke

    Full Text Available The etiology of emotion-related disorders such as anxiety or affective disorders is considered to be complex with an interaction of biological and environmental factors. Particular evidence has accumulated for alterations in the dopaminergic and noradrenergic system--partly conferred by catechol-O-methyltransferase (COMT gene variation--for the adenosinergic system as well as for early life trauma to constitute risk factors for those conditions. Applying a multi-level approach, in a sample of 95 healthy adults, we investigated effects of the functional COMT Val158Met polymorphism, caffeine as an adenosine A2A receptor antagonist (300 mg in a placebo-controlled intervention design and childhood maltreatment (CTQ as well as their interaction on the affect-modulated startle response as a neurobiologically founded defensive reflex potentially related to fear- and distress-related disorders. COMT val/val genotype significantly increased startle magnitude in response to unpleasant stimuli, while met/met homozygotes showed a blunted startle response to aversive pictures. Furthermore, significant gene-environment interaction of COMT Val158Met genotype with CTQ was discerned with more maltreatment being associated with higher startle potentiation in val/val subjects but not in met carriers. No main effect of or interaction effects with caffeine were observed. Results indicate a main as well as a GxE effect of the COMT Val158Met variant and childhood maltreatment on the affect-modulated startle reflex, supporting a complex pathogenetic model of the affect-modulated startle reflex as a basic neurobiological defensive reflex potentially related to anxiety and affective disorders.

  14. Genetic variation in the Catechol-O-Methyltransferase (COMT gene and morphine requirements in cancer patients with pain

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    Kaasa Stein

    2008-12-01

    Full Text Available Abstract Background Genetic variation contributes to differences in pain sensitivity and response to different analgesics. Catecholamines are involved in the modulation of pain and are partly metabolized by the catechol-O-methyltransferase (COMT enzyme. Genetic variability in the COMT gene may therefore contribute to differences in pain sensitivity and response to analgesics. It is shown that a polymorphism in the COMT gene, Rs4680 (Val158Met, influence pain sensitivity in human experimental pain and the efficacy for morphine in cancer pain treatment. In this study we wanted to investigate if variability in other regions in the COMT gene also contributes to interindividual variability in morphine efficacy. Results We genotyped 11 single nucleotide polymorphisms (SNPs throughout the COMT gene, and constructed haplotypes from these 11 SNPs, which were in Hardy-Weinberg equilibrium. We compared both genotypes and haplotypes against pharmacological, demographical and patient symptoms measurements in a Caucasian cancer patient cohort (n = 197 receiving oral morphine treatment for cancer pain. There were two frequent haplotypes (34.5% and 17.8% in our cohort. Multivariate analyses showed that patients carrying the most frequent haplotype (34.5% needed lower morphine doses than patients not carrying the haplotype, with a reduction factor of 0.71 (p = 0.005. On the allele level, carriers of alleles for six of the SNPs show weak associations in respect to morphine dose and the alleles associated with the lowest morphine doses constitute part of the most frequent haplotype. Conclusion This study suggests that genetic variability in the COMT gene influence the efficacy of morphine in cancer patients with pain, and that increased understanding of this variability is reached by expanding from analyses of single SNPs to haplotype construction and analyses.

  15. Catechol-O-methyltransferase val158met genotype determines effect of reboxetine on emotional memory in healthy male volunteers

    Science.gov (United States)

    Gibbs, Ayana A.; Bautista, Carla E.; Mowlem, Florence D.; Naudts, Kris H.; Duka, Dora T.

    2014-01-01

    Background Catechol-O-methyltransferase (COMT) metabolizes catecholamines in the prefrontal cortex (PFC). A common polymorphism in the COMT gene (COMT val158met) has pleiotropic effects on cognitive and emotional processing. The met allele has been associated with enhanced cognitive processing but impaired emotional processing relative to the val allele. Methods We genotyped healthy, white men in relation to the COMT val158met polymorphism. They were given a single 4 mg dose of the selective noradrenaline reuptake inhibitor (NRI) reboxetine or placebo in a randomized, double-blind between-subjects model and then completed an emotional memory task 2 hours later. Results We included 75 men in the study; 41 received reboxetine and 34 received placebo. In the placebo group, met/met carriers did not demonstrate the usual memory advantage for emotional stimuli that was observed in val carriers. Reboxetine restored this emotional enhancement of memory in met/met carriers, but had no significant effect in val carriers. Limitations We studied only men, thus limiting the generalizability of our findings. We also relied on self-reported responses to screening questions to establish healthy volunteer status, and in spite of the double-blind design, participants were significantly better than chance at identifying their intervention allocation. Conclusion Emotional memory is impaired in healthy met homozygotes and selectively improved in this group by reboxetine. This has potential translational implications for the use of reboxetine, which is currently licensed as an antidepressant in several countries, and edivoxetine, a new selective NRI currently in development. PMID:24467942

  16. Sexually dimorphic effects of catechol-O-methyltransferase (COMT inhibition on dopamine metabolism in multiple brain regions.

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    Linda M Laatikainen

    Full Text Available The catechol-O-methyltransferase (COMT enzyme metabolises catecholamines. COMT inhibitors are licensed for the adjunctive treatment of Parkinson's disease and are attractive therapeutic candidates for other neuropsychiatric conditions. COMT regulates dopamine levels in the prefrontal cortex (PFC but plays a lesser role in the striatum. However, its significance in other brain regions is largely unknown, despite its links with a broad range of behavioural phenotypes hinting at more widespread effects. Here, we investigated the effect of acute systemic administration of the brain-penetrant COMT inhibitor tolcapone on tissue levels of dopamine, noradrenaline, and the dopamine metabolites 3,4-dihydroxyphenylacetic acid (DOPAC and homovanillic acid (HVA. We examined PFC, striatum, hippocampus and cerebellum in the rat. We studied both males and females, given sexual dimorphisms in several aspects of COMT's function. Compared with vehicle, tolcapone significantly increased dopamine levels in the ventral hippocampus, but did not affect dopamine in other regions, nor noradrenaline in any region investigated. Tolcapone increased DOPAC and/or decreased HVA in all brain regions studied. Notably, several of the changes in DOPAC and HVA, particularly those in PFC, were more prominent in females than males. These data demonstrate that COMT alters ventral hippocampal dopamine levels, as well as regulating dopamine metabolism in all brain regions studied. They demonstrate that COMT is of significance beyond the PFC, consistent with its links with a broad range of behavioural phenotypes. Furthermore, they suggest that the impact of tolcapone may be greater in females than males, a finding which may be of clinical significance in terms of the efficacy and dosing of COMT inhibitors.

  17. Affect-modulated startle: interactive influence of catechol-O-methyltransferase Val158Met genotype and childhood trauma.

    Science.gov (United States)

    Klauke, Benedikt; Winter, Bernward; Gajewska, Agnes; Zwanzger, Peter; Reif, Andreas; Herrmann, Martin J; Dlugos, Andrea; Warrings, Bodo; Jacob, Christian; Mühlberger, Andreas; Arolt, Volker; Pauli, Paul; Deckert, Jürgen; Domschke, Katharina

    2012-01-01

    The etiology of emotion-related disorders such as anxiety or affective disorders is considered to be complex with an interaction of biological and environmental factors. Particular evidence has accumulated for alterations in the dopaminergic and noradrenergic system--partly conferred by catechol-O-methyltransferase (COMT) gene variation--for the adenosinergic system as well as for early life trauma to constitute risk factors for those conditions. Applying a multi-level approach, in a sample of 95 healthy adults, we investigated effects of the functional COMT Val158Met polymorphism, caffeine as an adenosine A2A receptor antagonist (300 mg in a placebo-controlled intervention design) and childhood maltreatment (CTQ) as well as their interaction on the affect-modulated startle response as a neurobiologically founded defensive reflex potentially related to fear- and distress-related disorders. COMT val/val genotype significantly increased startle magnitude in response to unpleasant stimuli, while met/met homozygotes showed a blunted startle response to aversive pictures. Furthermore, significant gene-environment interaction of COMT Val158Met genotype with CTQ was discerned with more maltreatment being associated with higher startle potentiation in val/val subjects but not in met carriers. No main effect of or interaction effects with caffeine were observed. Results indicate a main as well as a GxE effect of the COMT Val158Met variant and childhood maltreatment on the affect-modulated startle reflex, supporting a complex pathogenetic model of the affect-modulated startle reflex as a basic neurobiological defensive reflex potentially related to anxiety and affective disorders.

  18. The catechol-O-methyltransferase (COMT val158met polymorphism affects brain responses to repeated painful stimuli.

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    Marco L Loggia

    Full Text Available Despite the explosion of interest in the genetic underpinnings of individual differences in pain sensitivity, conflicting findings have emerged for most of the identified "pain genes". Perhaps the prime example of this inconsistency is represented by catechol-O-methyltransferase (COMT, as its substantial association to pain sensitivity has been reported in various studies, but rejected in several others. In line with findings from behavioral studies, we hypothesized that the effect of COMT on pain processing would become apparent only when the pain system was adequately challenged (i.e., after repeated pain stimulation. In the present study, we used functional Magnetic Resonance Imaging (fMRI to investigate the brain response to heat pain stimuli in 54 subjects genotyped for the common COMT val158met polymorphism (val/val = n 22, val/met = n 20, met/met = n 12. Met/met subjects exhibited stronger pain-related fMRI signals than val/val in several brain structures, including the periaqueductal gray matter, lingual gyrus, cerebellum, hippocampal formation and precuneus. These effects were observed only for high intensity pain stimuli after repeated administration. In spite of our relatively small sample size, our results suggest that COMT appears to affect pain processing. Our data demonstrate that the effect of COMT on pain processing can be detected in presence of 1 a sufficiently robust challenge to the pain system to detect a genotype effect, and/or 2 the recruitment of pain-dampening compensatory mechanisms by the putatively more pain sensitive met homozygotes. These findings may help explain the inconsistencies in reported findings of the impact of COMT in pain regulation.

  19. A catechol-like phenolic ligand-functionalized hydrothermal carbon: One-pot synthesis, characterization and sorption behavior toward uranium

    Energy Technology Data Exchange (ETDEWEB)

    Li, Bo; Ma, Lijian; Tian, Yin; Yang, Xiaodan; Li, Juan; Bai, Chiyao; Yang, Xiaoyu; Zhang, Shuang; Li, Shoujian, E-mail: sjli000616@scu.edu.cn; Jin, Yongdong, E-mail: jinyongdong@scu.edu.cn

    2014-04-01

    Highlights: • A new catechol-like ligand-functionalized hydrothermal carbon sorbent is synthesized. • A combination of bayberry tannin and glyoxal is firstly used as starting materials. • Simple, economically viable and environment-friendly synthesis method. • The sorbent exhibits high sorption capacity and distinct selectivity for uranium. - Abstract: We proposed a new approach for preparing an efficient uranium-selective solid phase extractant (HTC-btg) by choosing bayberry tannin as the main building block and especially glyoxal as crosslinking agent via a simple, economic, and green one-pot hydrothermal synthesis. The results of characterization and analysis show that after addition of glyoxal into only bayberry tannin-based hydrothermal reaction system, the as-synthesized HTC-btg displayed higher thermal stability, larger specific surface area and more than doubled surface phenolic hydroxyl groups. The sorption behavior of the sorbents toward uranium under various conditions was investigated in detail and the results indicated that the process is fast, endothermic, spontaneous, and pseudo-second-order chemisorption. The U(VI) sorption capacity reached up to 307.3 mg g{sup −1} under the current experimental conditions. The selective sorption in a specially designed multi-ion solution containing 12 co-existing cations over the range of pH 1.0–4.5 shown that the amount of uranium sorbed accounts for about 53% of the total sorption amount at pH 4.5 and distinctively about 85%, unreported so far to our knowledge, at pH 2.0. Finally, a possible mechanism involving interaction between uranyl ions and phenolic hydroxyl groups on HTC-btg was proposed.

  20. A self-assembled complex with a titanium(IV) catecholate core as a potential bimodal contrast agent.

    Science.gov (United States)

    Dehaen, Geert; Eliseeva, Svetlana V; Kimpe, Kristof; Laurent, Sophie; Vander Elst, Luce; Muller, Robert N; Dehaen, Wim; Binnemans, Koen; Parac-Vogt, Tatjana N

    2012-01-01

    A ditopic chelating ligand (H(6)4) that bears catechol and diethylenetriamine-N,N,N',N'',N''-pentaacetate (DTPA) has been designed and shown to specifically bind lanthanide(III) ions at the DTPA core ([Ln(H(2)4)(H(2)O)](-)) and further self-assemble with titanium(IV), thereby giving rise to the formation of a supramolecular metallostar complex with a lanthanide(III)-to-titanium(IV) ratio of 3:1, [(Ln4)(3)Ti(H(2)O)(3)](5-) (Ln=La, Eu, Gd). The efficacy of the metallostar complex as a potential bimodal optical/magnetic resonance imaging (MRI) agent has been evaluated. Nuclear magnetic relaxation dispersion (NMRD) measurements for the [(Gd4)(3)Ti(H(2)O)(3)](5-) complex have demonstrated an enhanced r(1) relaxivity that corresponds to 36.9 s(-1) mM(-1) per metallostar molecule at 20 MHz and 310 K, which is a result of a decreased tumbling rate. The ability of the complex to bind to human serum albumin (HSA) was also examined by relaxometric measurements. In addition, upon UV irradiation the [(Gd4)(3)Ti(H(2)O)(3)](5-) complex exhibits broad-band green emission in the range 400-750 nm with a maximum at 490 nm. Taking into account the high relaxivity and luminescence properties, the [(Gd4)(3)Ti(H(2)O)(3)](5-) complex is a good lead compound for the development of efficient bimodal contrast agents.

  1. Association between catechol-O-methyltrasferase Val108/158Met genotype and prefrontal hemodynamic response in schizophrenia.

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    Ryu Takizawa

    Full Text Available BACKGROUND: "Imaging genetics" studies have shown that brain function by neuroimaging is a sensitive intermediate phenotype that bridges the gap between genes and psychiatric conditions. Although the evidence of association between functional val108/158met polymorphism of the catechol-O-methyltransferase gene (COMT and increasing risk for developing schizophrenia from genetic association studies remains to be elucidated, one of the most topical findings from imaging genetics studies is the association between COMT genotype and prefrontal function in schizophrenia. The next important step in the translational approach is to establish a useful neuroimaging tool in clinical settings that is sensitive to COMT variation, so that the clinician could use the index to predict clinical response such as improvement in cognitive dysfunction by medication. Here, we investigated spatiotemporal characteristics of the association between prefrontal hemodynamic activation and the COMT genotype using a noninvasive neuroimaging technique, near-infrared spectroscopy (NIRS. METHODOLOGY/PRINCIPAL FINDINGS: Study participants included 45 patients with schizophrenia and 60 healthy controls matched for age and gender. Signals that are assumed to reflect regional cerebral blood volume were monitored over prefrontal regions from 52-channel NIRS and compared between two COMT genotype subgroups (Met carriers and Val/Val individuals matched for age, gender, premorbid IQ, and task performance. The [oxy-Hb] increase in the Met carriers during the verbal fluency task was significantly greater than that in the Val/Val individuals in the frontopolar prefrontal cortex of patients with schizophrenia, although neither medication nor clinical symptoms differed significantly between the two subgroups. These differences were not found to be significant in healthy controls. CONCLUSIONS/SIGNIFICANCE: These data suggest that the prefrontal NIRS signals can noninvasively detect the impact

  2. 3-(2-hydroxyphenyl)catechol as substrate for proximal meta ring cleavage in dibenzofuran degradation by Brevibacterium sp. strain DPO 1361

    Energy Technology Data Exchange (ETDEWEB)

    Strubel, V.; Engesser, K.H.; Fischer, P.; Knackmuss, H.J. (Univ. Stuttgart (West Germany))

    1991-03-01

    Dibenzofuran (DBF) has been used in some recent studies as a model compound for investigating the microbial degradation of cyclic biaryl ethers. Public attention has focused on this class of compounds, since it comprises some of the most pernicious and persistent molecules, such as TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin). For DBF, the most simple cyclic biaryl ether, a novel degradation mechanism involving angular dioxygenation has been described with 3-(2-hydroxyphenyl)catechol (HPC) as a central intermediate. Definite proof for this mechanism is presented in this paper, and the total degradation of DBF by Brevibacterium is described.

  3. Novel, Unifying Mechanism for Mescaline in The Central Nervous System: Electrochemistry, Catechol Redox Metabolite, Receptor, Cell Signaling and Structure Activity Relationships

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    Peter Kovacic

    2009-01-01

    Full Text Available A unifying mechanism for abused drugs has been proposed previously from the standpoint of electron transfer. Mescaline can be accommodated within the theoretical framework based on redox cycling by the catechol metabolite with its quinone counterpart. Electron transfer may play a role in electrical effects involving the nervous system in the brain. This approach is in accord with structure activity relationships involving mescaline, abused drugs, catecholamines and etoposide. Inefficient demethylation is in keeping with the various drug properties, such as requirement for high dosage and slow acting.

  4. Polymer-pendant ligand chemistry. 1. Reactions of organoarsonic acids and arsenic acid with catechol ligands bonded to polystryene-divinylbenzene and regeneration of the ligand site by a simple hydrolysis procedure

    Energy Technology Data Exchange (ETDEWEB)

    Fish, R.H.; Tannous, R.S.

    1985-12-18

    A novel method is reported for reactions of organoarsonic acids and arsenic acid, known to be present in oil shale and its pyrolysis products, with catechol ligands bonded to either 2% or 20% cross-linked methylated polystyrene-divinylbenzene (PS-DVB) resins. A previous study with catechol-bonded ligands on PS-DVB resins dealt with their reactions with metal ions in aqueous solution and showed a selectivity toward Hg/sup 2 +/ ions. As far as we have been able to determine, reactions of this polymer-supported ligand with organometallic compounds or inorganic anions have not been reported. 9 references, 2 figures, 1 table.

  5. New avenues for ligand-mediated processes--expanding metal reactivity by the use of redox-active catechol, o-aminophenol and o-phenylenediamine ligands.

    Science.gov (United States)

    Broere, Daniël L J; Plessius, Raoul; van der Vlugt, Jarl Ivar

    2015-10-01

    Redox-active ligands have evolved from being considered spectroscopic curiosities - creating ambiguity about formal oxidation states in metal complexes - to versatile and useful tools to expand on the reactivity of (transition) metals or to even go beyond what is generally perceived possible. This review focusses on metal complexes containing either catechol, o-aminophenol or o-phenylenediamine type ligands. These ligands have opened up a new area of chemistry for metals across the periodic table. The portfolio of ligand-based reactivity invoked by these redox-active entities will be discussed. This ranges from facilitating oxidative additions upon d(0) metals or cross coupling reactions with cobalt(iii) without metal oxidation state changes - by functioning as an electron reservoir - to intramolecular ligand-to-substrate single-electron transfer to create a reactive substrate-centered radical on a Pd(ii) platform. Although the current state-of-art research primarily consists of stoichiometric and exploratory reactions, several notable reports of catalysis facilitated by the redox-activity of the ligand will also be discussed. In conclusion, redox-active ligands containing catechol, o-aminophenol or o-phenylenediamine moieties show great potential to be exploited as reversible electron reservoirs, donating or accepting electrons to activate substrates and metal centers and to enable new reactivity with both early and late transition as well as main group metals.

  6. Interactions among catechol-O-methyltransferase genotype, parenting, and sex predict children’s internalizing symptoms and inhibitory control: Evidence for differential susceptibility

    Science.gov (United States)

    SULIK, MICHAEL J.; EISENBERG, NANCY; SPINRAD, TRACY L.; LEMERY-CHALFANT, KATHRYN; SWANN, GREGORY; SILVA, KASSONDRA M.; REISER, MARK; STOVER, DARYN A.; VERRELLI, BRIAN C.

    2015-01-01

    We used sex, observed parenting quality at 18 months, and three variants of the catechol-O-methyltransferase gene (Val158Met [rs4680], intron1 [rs737865], and 3′-untranslated region [rs165599]) to predict mothers’ reports of inhibitory and attentional control (assessed at 42, 54, 72, and 84 months) and internalizing symptoms (assessed at 24, 30, 42, 48, and 54 months) in a sample of 146 children (79 male). Although the pattern for all three variants was very similar, Val158Met explained more variance in both outcomes than did intron1, the 3′-untranslated region, or a haplotype that combined all three catechol-O-methyltransferase variants. In separate models, there were significant three-way interactions among each of the variants, parenting, and sex, predicting the intercepts of inhibitory control and internalizing symptoms. Results suggested that Val158Met indexes plasticity, although this effect was moderated by sex. Parenting was positively associated with inhibitory control for methionine–methionine boys and for valine–valine/valine–methionine girls, and was negatively associated with internalizing symptoms for methionine–methionine boys. Using the “regions of significance” technique, genetic differences in inhibitory control were found for children exposed to high-quality parenting, whereas genetic differences in internalizing were found for children exposed to low-quality parenting. These findings provide evidence in support of testing for differential susceptibility across multiple outcomes. PMID:25159270

  7. Catechol Groups Enable Reactive Oxygen Species Scavenging-Mediated Suppression of PKD-NFkappaB-IL-8 Signaling Pathway by Chlorogenic and Caffeic Acids in Human Intestinal Cells.

    Science.gov (United States)

    Shin, Hee Soon; Satsu, Hideo; Bae, Min-Jung; Totsuka, Mamoru; Shimizu, Makoto

    2017-02-20

    Chlorogenic acid (CHA) and caffeic acid (CA) are phenolic compounds found in coffee, which inhibit oxidative stress-induced interleukin (IL)-8 production in intestinal epithelial cells, thereby suppressing serious cellular injury and inflammatory intestinal diseases. Therefore, we investigated the anti-inflammatory mechanism of CHA and CA, both of which inhibited hydrogen peroxide (H₂O₂)-induced IL-8 transcriptional activity. They also significantly suppressed nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) transcriptional activity, nuclear translocation of the p65 subunit, and phosphorylation of IκB kinase (IKK). Additionally, upstream of IKK, protein kinase D (PKD) was also suppressed. Finally, we found that they scavenged H₂O₂-induced reactive oxygen species (ROS) and the functional moiety responsible for the anti-inflammatory effects of CHA and CA was the catechol group. Therefore, we conclude that the presence of catechol groups in CHA and CA allows scavenging of intracellular ROS, thereby inhibiting H₂O₂-induced IL-8 production via suppression of PKD-NF-κB signaling in human intestinal epithelial cells.

  8. Assessment of toxicological interactions of benzene and its primary degradation products (catechol and phenol) using a lux-modified bacterial bioassay

    Energy Technology Data Exchange (ETDEWEB)

    Boyd, E.M. [Inst. of Terrestrial Ecology, Huntingdon (United Kingdom)]|[Univ. of Aberdeen (United Kingdom). Dept. of Plant and Soil Science; Meharg, A.A.; Wright, J. [Inst. of Terrestrial Ecology, Huntingdon (United Kingdom); Killham, K. [Univ. of Aberdeen (United Kingdom). Dept. of Plant and Soil Science

    1997-05-01

    A bacterial bioassay has been developed to assess the relative toxicities of xenobiotics commonly found in contaminated soils, river waters, and ground waters. The assay utilized decline in luminescence of lux-marked Pseudomonas fluorescens on exposure to xenobiotics. Pseudomonas fluorescens is a common bacterium in the terrestrial environment, providing environmental relevance to soil, river, and ground water systems. Three principal environmental contaminants associated with benzene degradation were exposed to the luminescence-marked bacterial biosensor to assess their toxicity individually and in combination. Median effective concentration (EC50) values for decline in luminescence were determined for benzene, catechol, and phenol and were found to be 39.9, 0.77, and 458.6 mg/L, respectively. Catechol, a fungal and bacterial metabolite of benzene, was found to be significantly more toxic to the biosensor than was the parent compound benzene, showing that products of xenobiotic biodegradation may be more toxic than the parent compounds. Combinations of parent compounds and metabolites were found to be significantly more toxic to the bioassay than were the individual compounds themselves. Development of this bioassay has provided a rapid screening system suitable for assessing the toxicity of xenobiotics commonly found in contaminated soil, river, and ground-water environments. The assay can be utilized over a wide pH range is therefore more applicable to such environmental systems than bioluminescence-based bioassays that utilize marine organisms and can only be applied over a limited pH and salinity range.

  9. Interaction of photoactive catechol with TiO{sub 2} anatase (1 0 1) surface: A periodic density functional theory study

    Energy Technology Data Exchange (ETDEWEB)

    Xu Ying [Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350002 (China); Chen Wenkai [Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350002 (China); Liu Shuhong [Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350002 (China); Cao Meijuan [Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350002 (China); Li Junqian [Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350002 (China)], E-mail: jqli@fzu.edu.cn

    2007-01-08

    The plane-wave function method, based on density functional theory, has been used to calculate the adsorption, electronic band structures and optical absorption spectra of molecular and dissociative catechol adsorbed on TiO{sub 2} anatase (1 0 1) surface. The obtained electronic structures of anatase (1 0 1) surface are similar with the previous theoretical works for anatase bulk. Our calculations reveal that one type of molecular catechol adsorption on (1 0 1) surface almost has no effect on the anatase optical absorption threshold; while another type of molecular adsorption and several dissociative adsorptions on (1 0 1) surface could lead to large red shifts of the absorption threshold. The dissociative adsorption at the defect site of (1 0 1) surface is also examined, and causes the strongest light absorption in the visible region. These results are in agreement with other experimental and theoretical studies reasonably. It is very important for the understanding and further development of photovoltaic materials that are active under visible light.

  10. Catechol Groups Enable Reactive Oxygen Species Scavenging-Mediated Suppression of PKD-NFkappaB-IL-8 Signaling Pathway by Chlorogenic and Caffeic Acids in Human Intestinal Cells

    Directory of Open Access Journals (Sweden)

    Hee Soon Shin

    2017-02-01

    Full Text Available Chlorogenic acid (CHA and caffeic acid (CA are phenolic compounds found in coffee, which inhibit oxidative stress-induced interleukin (IL-8 production in intestinal epithelial cells, thereby suppressing serious cellular injury and inflammatory intestinal diseases. Therefore, we investigated the anti-inflammatory mechanism of CHA and CA, both of which inhibited hydrogen peroxide (H2O2-induced IL-8 transcriptional activity. They also significantly suppressed nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB transcriptional activity, nuclear translocation of the p65 subunit, and phosphorylation of IκB kinase (IKK. Additionally, upstream of IKK, protein kinase D (PKD was also suppressed. Finally, we found that they scavenged H2O2-induced reactive oxygen species (ROS and the functional moiety responsible for the anti-inflammatory effects of CHA and CA was the catechol group. Therefore, we conclude that the presence of catechol groups in CHA and CA allows scavenging of intracellular ROS, thereby inhibiting H2O2-induced IL-8 production via suppression of PKD-NF-κB signaling in human intestinal epithelial cells.

  11. Preparation, Investigation and the Study of the Effect of Mn(II Complex of Catechol and 2-Aminopyridine on Seed Germination

    Directory of Open Access Journals (Sweden)

    F. I. El-Moshaty

    2011-01-01

    Full Text Available The formation of mixed ligand complex of Mn(II with catechol (L1 and 2-aminopyridine (L2 was determined by elemental analyses (C, H and N, molar conductance measurement, thermogravimetric analysis, infrared, electronic and electron paramagnetic resonance spectroscopies. The elemental analysis data show the formation of 1:1:1 [M: L1: L2] complex. The molar conductance measurement shows a non-electrolyte nature. The thermogravimetric analysis data of the complex display the existence of hydrated and coordinated water molecules. The infrared spectral data exhibit the coordination sites that are through -OH,-C=N and –NH2 groups. The electronic spectral data display the electronic transitions of the ligands and suggest an octahedral structure for the complex. The electron paramagnetic resonance spectrum of the complex reveals the existence of paramagnetic phenomena and supports its geometrical structure. Seed germination and root length of grass were also assayed under the effect of MnCl2.4H2O, catechol, 2-aminopyridine and its complex. Mn(II salt was the most effective on germination than its complex which possess the high test effect on root length, while the ligands are the least active of all.

  12. Catechol, a major component of smoke, influences primary root growth and root hair elongation through reactive oxygen species-mediated redox signaling.

    Science.gov (United States)

    Wang, Ming; Schoettner, Matthias; Xu, Shuqing; Paetz, Christian; Wilde, Julia; Baldwin, Ian T; Groten, Karin

    2017-03-01

    Nicotiana attenuata germinates from long-lived seedbanks in native soils after fires. Although smoke signals have been known to break seed dormancy, whether they also affect seedling establishment and root development remains unclear. In order to test this, seedlings were treated with smoke solutions. Seedlings responded in a dose-dependent manner with significantly increased primary root lengths, due mainly to longitudinal cell elongation, increased numbers of lateral roots and impaired root hair development. Bioassay-driven fractionations and NMR were used to identify catechol as the main active compound for the smoke-induced root phenotype. The transcriptome analysis revealed that mainly genes related to auxin biosynthesis and redox homeostasis were altered after catechol treatment. However, histochemical analyses of reactive oxygen species (ROS) and the inability of auxin applications to rescue the phenotype clearly indicated that highly localized changes in the root's redox-status, rather than in levels of auxin, are the primary effector. Moreover, H2 O2 application rescued the phenotype in a dose-dependent manner. Chemical cues in smoke not only initiate seed germination, but also influence seedling root growth; understanding how these cues work provides new insights into the molecular mechanisms by which plants adapt to post-fire environments.

  13. 对叔丁基邻苯二酚混合物组成测定法%Detection Method of Tert-butyl Catechol Mixture Composition

    Institute of Scientific and Technical Information of China (English)

    高山

    2013-01-01

      文章对对叔丁基邻苯二酚混合物组成的测定法进行了充分的论证,并得出 SE-54、20 m 毛细管色谱柱可用于对叔丁基邻苯二酚产品组分分析。较佳操作条件为:载气压力:0.08 MPa;柱温:170℃;汽化室温度:300℃;检测器温度250℃;进样量:0.2μL。%Full demonstration of detection method of Tert-butyl catechol mixture composition was made in the paper. The Capillary Column of SE-54, 20 m can be used in Tert-butyl catechol product component analysis. The better operation conditions were the pressure of the carrier gas was 0.08 MPa, column temperature was 170 ℃, vaporizing chamber temperature was 300 ℃, detector temperature was 250 ℃, injection volume was 0.2 μL.

  14. ISOLATION AND CHARACTERIZATION OF A MOLYBDENUM-REDUCING, PHENOL- AND CATECHOL-DEGRADING PSEUDOMONAS PUTIDA STRAIN AMR-12 IN SOILS FROM EGYPT

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    M. Abd. AbdEl-Mongy

    2016-02-01

    Full Text Available Sites contaminated with both heavy metals and organic xenobiotic pollutants warrants the effective use of either a multitude of bacterial degraders or bacteria having the capacity to detoxify numerous toxicants simultaneously. A molybdenum-reducing bacterium with the capacity to degrade phenolics is reported. Molybdenum (sodium molybdate reduction was optimum between pH 6.0 and 7.0 and between 20 and 30 °C. The most suitable electron donor was glucose. A narrow range of phosphate concentrations between 5.0 and 7.5 mM was required for optimal reduction, while molybdate between 20 and 30 mM were needed for optimal reduction. The scanning absorption spectrum of the molybdenum blue produced indicated that Mo-blue is a reduced phosphomolybdate. Molybdenum reduction was inhibited by the heavy metals mercury, silver and chromium. Biochemical analysis identified the bacterium as Pseudomonas putida strain Amr-12. Phenol and phenolics cannot support molybdenum reduction. However, the bacterium was able to grow on the phenolic compounds (phenol and catechol with observable lag periods. Maximum growth on phenol and catechol occurred around the concentrations of 600 mg∙L-1. The ability of this bacterium to detoxify molybdenum and grown on toxic phenolic makes this bacterium an important tool for bioremediation.

  15. Protective activity of the Uncaria tomentosa extracts on human erythrocytes in oxidative stress induced by 2,4-dichlorophenol (2,4-DCP) and catechol.

    Science.gov (United States)

    Bors, Milena; Bukowska, Bożena; Pilarski, Radosław; Gulewicz, Krzysztof; Oszmiański, Jan; Michałowicz, Jaromir; Koter-Michalak, Maria

    2011-09-01

    The purpose of this study was to evaluate the effect of the ethanolic and aqueous extracts of Uncaria tomentosa on human erythrocytes and additionally the assessment of protective effect of these extracts on hemolysis induction, hemoglobin oxidation, and changes in the level of reactive oxygen species (ROS) and lipid peroxidation, which were provoked by selected xenobiotics, i.e. 2,4-dichlorophenol (2,4-DCP) and catechol. All tested extracts, even at a very high concentration of 500 μg/ml were not toxic to the erythrocytes because they did not cause lipid peroxidation, increase methemoglobin and ROS levels nor provoked hemolysis. The results of this study also revealed protective effect of extracts of U. tomentosa. The extracts studied depleted the extent of hemoglobin oxidation and lipid peroxidation as well as decreased the level of ROS and hemolysis, which was provoked by 2,4-DCP. No protective activity of the extracts against catechol action, which is a precursor of semiquinones in cell was found. A difference in the effect of the extracts studied was observed. Ethanol-based extracts revealed more pronounced ability to inhibit oxidation processes in human erythrocytes.

  16. Catechol Groups Enable Reactive Oxygen Species Scavenging-Mediated Suppression of PKD-NFkappaB-IL-8 Signaling Pathway by Chlorogenic and Caffeic Acids in Human Intestinal Cells

    Science.gov (United States)

    Shin, Hee Soon; Satsu, Hideo; Bae, Min-Jung; Totsuka, Mamoru; Shimizu, Makoto

    2017-01-01

    Chlorogenic acid (CHA) and caffeic acid (CA) are phenolic compounds found in coffee, which inhibit oxidative stress-induced interleukin (IL)-8 production in intestinal epithelial cells, thereby suppressing serious cellular injury and inflammatory intestinal diseases. Therefore, we investigated the anti-inflammatory mechanism of CHA and CA, both of which inhibited hydrogen peroxide (H2O2)-induced IL-8 transcriptional activity. They also significantly suppressed nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) transcriptional activity, nuclear translocation of the p65 subunit, and phosphorylation of IκB kinase (IKK). Additionally, upstream of IKK, protein kinase D (PKD) was also suppressed. Finally, we found that they scavenged H2O2-induced reactive oxygen species (ROS) and the functional moiety responsible for the anti-inflammatory effects of CHA and CA was the catechol group. Therefore, we conclude that the presence of catechol groups in CHA and CA allows scavenging of intracellular ROS, thereby inhibiting H2O2-induced IL-8 production via suppression of PKD-NF-κB signaling in human intestinal epithelial cells. PMID:28230729

  17. Alkylation of catechol with tert-butyl alcohol catalyzed by mesoporous acidic montmorillonite heterostructure catalysts%中孔酸性蒙脱石基复合材料催化邻苯二酚-叔丁醇烷基化反应研究

    Institute of Scientific and Technical Information of China (English)

    周春晖; 葛忠华; 李小年; 童东绅; 李庆伟; 郭红强

    2004-01-01

    The liquid phase alkylation of catechol with tert-butyl alcohol to produce 4-tert-butyl catechol(4-TBC)was carried out over MCM-41,HZSM-5,H-exchanged montmorillonite and novel acidic porous montmorillonite heterostructures(PMHs).Upon all catalysts tested,4-TBC is the main product and 3-tert-butyl catechol(3-TBC)and 3,5-di-tert-butyl catechol are the side products.The synthetic PMHs showed higher conversion of catechol and better selectivity to 4-TBC compared to other solid acid catalysts tested.Over the PMHs derived from H-exchanged montmorillonite through template extraction processes,the suitable reaction temperature is ca 410 K,the ratio of catechol to tert-butyl alcohol is 1:2.Increasing the amount of catalyst(lower weight hourly space velocity)can improve the conversion of catechol and influence the selectivity slightly.The reasonable reaction time is ca 8 h.The type and strength of acidity of H-montmorillonite and PMH were determined by pyridine adsorption FT-IR and ammonia temperature-programmed desorption techniques.The medium and strong acid sites are conducive to producing 4-TBC and the weak acid sites to facilitating the 3-TBC formation.The differences between the PMHs from calcination and those from extraction are attributed to proton migration and acidity change in the gallery surface.

  18. Effect of an allophanic soil on humification reactions between catechol and glycine: Spectroscopic investigations of reaction products

    Science.gov (United States)

    Fukushima, Masami; Miura, Akitaka; Sasaki, Masahide; Izumo, Kenji

    2009-01-01

    Adduction of amino acids to phenols is a possible humification reaction pathway [F.J. Stevenson, Humus Chemistry: Genesis, Composition, Reaction, second ed., Wiley, New York, 1994, pp. 188-211; M.C. Wang, P.M. Huang, Sci. Total Environ. 62 (1987) 435; M.C. Wang, P.M. Huang, Soil Sci. Soc. Am. J. 55 (1991) 1156; M.C. Wang, P.M. Huang, Geoderma 112 (2003) 31; M.C. Wang, P.M. Huang, Geoderma 124 (2005) 415]. To elucidate the reaction kinetics and products of abiotic humification, the effects of an allophanic soil on the adduction of amino acids to phenols were investigated using catechol (CT) and glycine (Gly) as a model phenol and amino acid, respectively. An aqueous solution containing CT and Gly (pH 7.0) in the presence of allophanic soil was incubated for 2 weeks, and the kinetics of the humification reactions were monitored by analysis of absorptivity at 600 nm ( E600). A mixture of CT and Gly in the absence of allophanic soil was used as a control. The E600 value increased markedly in the presence of allophanic soil. In addition, unreacted CT was detected in the control reaction mixture, but not in the allophane-containing reaction mixture. Under the sterilized conditions, absorbance at 600 nm for the control reaction mixture was significantly smaller than that for the allophanic soil-containing reaction mixture, which indicates there was no microbial participation during incubation. These results indicate that the allophanic soil effectively facilitated humification reactions between CT and Gly. The reaction mixtures were acidified and humic-like acid (HLA) was isolated as a precipitate. The elemental composition, acidic functional group contents, molecular weight, FT-IR, solid-state CP-MAS 13C NMR, and 1H NMR spectra of the purified HLAs were analyzed. The results of these analyses indicate that the nitrogen atom of Gly binds to the aromatic carbon of CT in the HLA products.

  19. Genetic contribution of catechol-O-methyltransferase variants in treatment outcome of low back pain: a prospective genetic association study

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    Omair Ahmad

    2012-05-01

    Full Text Available Abstract Background Treatment outcome of low back pain (LBP is associated with inter-individual variations in pain relief and functional disability. Genetic variants of catechol-O-methyltransferase (COMT gene have previously been shown to be associated with pain sensitivity and pain medication. This study examines the association between COMT polymorphisms and 7–11 year change in Oswestry Disability Index (ODI and Visual Analog Score (VAS for LBP as clinical outcome variables in patients treated with surgical instrumented lumbar fusion or cognitive intervention and exercise. Methods 93 unrelated patients with chronic LBP for duration of >1 year and lumbar disc degeneration (LDD were treated with lumbar fusion (N = 60 or cognitive therapy and exercises (N = 33. Standardised questionnaires assessing the ODI, VAS LBP, psychological factors and use of analgesics, were answered by patients both at baseline and at 7–11 years follow-up. Four SNPs in the COMT gene were successfully genotyped. Single marker as well as haplotype association with change in ODI and VAS LBP, were analyzed using Haploview, linear regression and R-package Haplostats. P-values were not formally corrected for multiple testing as this was an explorative study. Results Association analysis of individual SNPs adjusted for covariates revealed association of rs4633 and rs4680 with post treatment improvement in VAS LBP (p = 0.02, mean difference (β = 13.5 and p = 0.02, β = 14.2 respectively. SNPs, rs4633 and rs4680 were found to be genotypically similar and in strong linkage disequilibrium (LD. A significant association was found with covariates, analgesics (p = 0.001, β = 18.6; anxiety and depression (p = 0.008, β = 15.4 and age (p = 0.03, mean difference per year (β = 0.7 at follow-up. There was a tendency for better improvement among heterozygous patients compared to the homozygous. No association was observed for the

  20. Sorption studies of heavy metal ions by salicylic acid–formaldehyde–catechol terpolymeric resin: Isotherm, kinetic and thermodynamics

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    Riddhish R. Bhatt

    2015-05-01

    Full Text Available Terpolymeric resin has been synthesized by condensing salicylic acid with catechol employing formaldehyde as a cross linking agent at 80 ± 5 °C using DMF as a solvent. The resin was characterized by elemental analysis, FTIR, XRD and thermal analysis (TGA, DTA and DTG. The morphology of the resin was studied by optical photographs and scanning electron micrographs (SEM at different magnifications. The physico-chemical properties have been studied. The uptake behavior of various metal ions viz. Ni(II, Cu(II, Zn(II, Cd(II and Pb(II towards synthesized resin has been studied depending on contact time, pH and temperature. The selectivity order found is: Cu(II > Zn(II > Pb(II > Ni(II > Cd(II. The sorption data obtained at optimized conditions were analyzed by six two parameter isotherm models like Langmuir, Freundlich, Temkin, Dubinin–Radushkevich (D–R, Halsey and Harkins–Jura. The Langmuir, Freundlich and Dubinin–Radushkevich (D–R isotherms were found better to describe the sorption data with high correlation for the adsorption with a low SSE value for all the metals under study. The adsorption capacities of the SFC resin for removal of Ni(II, Cu(II, Zn(II, Cd(II and Pb(II were determined with the Langmuir equation and found to be 0.815, 1.104, 1.215, 0.498, and 0.931 mmol/g respectively. The adsorption process follows first order kinetics and specific rate constant Kr was obtained by the application of Lagergren equation. Thermodynamic parameters viz. ΔGads, ΔSads and ΔHads have also been calculated for the metal-resin systems. The external diffusion rate constant (Ks and intra-particle diffusion rate constant (Kid were calculated by Spahn–Schlunder and Weber–Morris models respectively. Desorption studies were done using various desorbing agents viz. de-ionized water, boiled water, various concentrations of HCl, ammonia, thiourea, citric acid and tartaric acid.

  1. The Influence of the Val158Met Catechol-O-Methyltransferase Polymorphism on the Personality Traits of Bipolar Patients

    Science.gov (United States)

    Dávila, Wendy; Basterreche, Nieves; Arrue, Aurora; Zamalloa, María I.; Gordo, Estíbaliz; Dávila, Ricardo; González-Torres, Miguel A.; Zumárraga, Mercedes

    2013-01-01

    Introduction Certain personality traits and genetic polymorphisms are contributing factors to bipolar disorder and its symptomatology, and in turn, this syndrome influences personality. The aim of the present study is to compare the personality traits of euthymic bipolar patients with healthy controls and to investigate the effect of the catechol-O-methyltransferase (COMT) Val158Met genotype on those traits. We recruited thirty seven bipolar I patients in euthymic state following a manic episode and thirty healthy controls and evaluated their personality by means of the Cloninger’s Temperament and Character Inventory (version TCI-R-140). We assessed the influence of the polymorphism Val158Met in the COMT gene on the personality of these patients. The patients scored higher than controls in harm avoidance (61.3±12.5 vs. 55.3±8.1) and self-transcendence (45.3±12.8 vs. 32.7±8.2) and scored lower than controls in self-directedness (68.8±13.3 vs. 79.3±8.1), cooperativeness (77.1±9.1 vs. 83.9±6.5) and persistence (60.4±15.1 vs. 67.1±8.9). The novelty seeking dimension associates with the Val158Met COMT genotype; patients with the low catabolic activity genotype, Met/Met, show a higher score than those with the high catabolic activity genotype, Val/Val. Conclusions Suffering from bipolar disorder could have an impact on personality. A greater value in harm avoidance may be a genetic marker for a vulnerability to the development of a psychiatric disorder, but not bipolar disorder particularly, while a low value in persistence may characterize affective disorders or a subgroup of bipolar patients. The association between novelty seeking scores and COMT genotype may be linked with the role dopamine plays in the brain’s reward circuits. PMID:23646156

  2. The Flexible Mind Is Associated with the Catechol-O-Methyltransferase (COMT) Val[superscript 158]Met Polymorphism: Evidence for a Role of Dopamine in the Control of Task-Switching

    Science.gov (United States)

    Colzato, Lorenza S.; Waszak, Florian; Nieuwenhuis, Sander; Posthuma, Danielle; Hommel, Bernhard

    2010-01-01

    Genetic variability related to the catechol-O-methyltransferase (COMT) gene Val[superscript 128]Met polymorphism) has received increasing attention as a possible modulator of cognitive control functions. Recent evidence suggests that the Val[superscript 128]Met genotype may differentially affect cognitive stability and flexibility, in such a way…

  3. Research progress of methods for detecting catechol and hydroquinone in water%水体中邻苯二酚和对苯二酚检测方法的研究进展

    Institute of Scientific and Technical Information of China (English)

    王勇; 张闪; 董莹; 屈建莹

    2015-01-01

    Catechol and hydroquinone are major pollutants in water and have serious damage to organisms .Therefore ,it is of special significance to establish fast ,facile ,sensitive and efficient methods to identify and quantify trace catechol and hydroquinone .A review is provided of the research progress of the major methods for detecting catechol and hydroquinone ,including chromatography ,spectrophotometry ,chemiluminescence and electrochemistry ,and the fea‐tures of various methods are briefed .Furthermore ,the development trend of the methods for the determination of catechol and hydroquninone is discussed .%邻苯二酚和对苯二酚是水体中重要的污染物,对生物体具有严重的危害作用,故实现邻苯二酚与对苯二酚的快速简便、灵敏高效的检测具有十分重要的意义。本文作者综述了近几十年来国内外检测邻苯二酚和对苯二酚的主要方法,如色谱法、分光光度法、化学发光法和电化学分析方法,阐述了各种检测方法的特点;并探讨了两种物质的检测方法的发展趋势。

  4. Oxidation stability of biodiesel fuels and blends using the Rancimat and PetroOXY methods. Effect of 4-allyl-2,6-dimethoxyphenol and catechol as biodiesel additives on oxidation stability.

    Science.gov (United States)

    Botella, Lucía; Bimbela, Fernando; Martín, Lorena; Arauzo, Jesús; Sánchez, José L

    2014-01-01

    IN THE PRESENT WORK, SEVERAL FATTY ACID METHYL ESTERS (FAME) HAVE BEEN SYNTHESIZED FROM VARIOUS FATTY ACID FEEDSTOCKS: used frying olive oil, pork fat, soybean, rapeseed, sunflower, and coconut. The oxidation stabilities of the biodiesel samples and of several blends have been measured simultaneously by both the Rancimat method, accepted by EN14112 standard, and the PetroOXY method, prEN16091 standard, with the aim of finding a correlation between both methodologies. Other biodiesel properties such as composition, cold filter plugging point (CFPP), flash point (FP), and kinematic viscosity have also been analyzed using standard methods in order to further characterize the biodiesel produced. In addition, the effect on the biodiesel properties of using 4-allyl-2,6-dimethoxyphenol and catechol as additives in biodiesel blends with rapeseed and with soybean has also been analyzed. The use of both antioxidants results in a considerable improvement in the oxidation stability of both types of biodiesel, especially using catechol. Adding catechol loads as low as 0.05% (m/m) in blends with soybean biodiesel and as low as 0.10% (m/m) in blends with rapeseed biodiesel is sufficient for the oxidation stabilities to comply with the restrictions established by the European EN14214 standard. An empirical linear equation is proposed to correlate the oxidation stability by the two methods, PetroOXY and Rancimat. It has been found that the presence of either catechol or 4-allyl-2,6-dimethoxyphenol as additives affects the correlation observed.

  5. Effects of garlic on cellular doubling time and DNA strand breaks caused by UV light and BPL, enhanced with catechol and TPA

    Energy Technology Data Exchange (ETDEWEB)

    Baturay, N.Z.; Gayle, F.; Liu, S.; Kreidinger, C.

    1995-11-01

    3T3 cell cultures were exposed to UV light and Beta-Propiolactone. Neoplastic cell transformation (TF) was demonstrated after concurrent addition of catechol, or repeated addition of TPA. Addition of garlic to all fluences/concentrations of the carcinogen/cocarcinogen/promoter groups reduced the number of transformed foci/dish by at least 40%. Since the cell cycle is prolonged following exposure to carcinogens, it is likely the cell requires a longer time to repair this damage. The doubling time (DT) was extended from 12 to 36 hrs. when cells were exposed to BPL and from 12 o 28 hrs. when cells were exposed to 3.0J/M2/sec. If an anticarcinogenic compound is also added, it is reasonable to assume that the cell cycle may be further elongated. The cell cycle, denoted by DT was lengthened from 12 to 47 hrs and from 12 to 86 hrs for BPL and UVC, respectively. The extensions occurred in a dope dependent manner. The concentrations of the cocarcinogen and promoter remained constant throughout the experiment. When strand breaks were determined at the same dose sequences, by alkaline elution, more repair was seen with garlic where the lowest and middle doses of BPL were used and almost no decrease in % DNA eluted was seen with UVC exposed cells. With catechol, there was a two-fold decrease in % DNA eluted at the lowest and middle fluences. When TPA was added, all three fluences of UVC showed more than a threefold decrease in % DNA eluted. BPS with both TPA and catechol, again showed a reduction in strand breaks only low and middle doses. Both a direct-acting alkylating agent, BPL, and a physical carcinogen, UVC, were homogeneously affected, in terms of doubling time, but not when strand break repair was examined. A separate mechanism may be responsible for repair, and the mechanism associated with combinations of physical carcinogen enhancing agents combined with some non-carcinogens may be more profoundly affected by some natural products.

  6. Iron(III) complexes of tripodal tetradentate 4N ligands as functional models for catechol dioxygenases: the electronic vs. steric effect on extradiol cleavage.

    Science.gov (United States)

    Balamurugan, Mani; Vadivelu, Prabha; Palaniandavar, Mallayan

    2014-10-21

    A few mononuclear iron(iii) complexes of the type [Fe(L)Cl2]Cl , where L is a tetradentate tripodal 4N ligand such as N,N-dimethyl-N',N'-bis(pyrid-2-ylmethyl)ethane-1,2-diamine (), N,N-diethyl-N',N'-bis(pyrid-2-ylmethyl)ethane-1,2-diamine (), N,N-dimethyl-N',N'-bis-(6-methylpyrid-2-ylmethyl)ethane-1,2-diamine (), N,N-dimethyl-N'-(pyrid-2-ylmethyl)-N'-(1-methyl-1H-imidazol-2-ylmethyl)ethane-1,2-diamine (), N,N-dimethyl-N',N'-bis(1-methyl-1H-imidazol-2-ylmethyl)ethane-1,2-diamine () and N,N-dimethyl-N',N'-bis(quinolin-2-ylmethyl)ethane-1,2-diamine (), have been isolated and characterized by CHN analysis, UV-Visible spectroscopy and electrochemical methods. The complex cation [Fe(H)Cl3](+) possesses a distorted octahedral geometry in which iron is coordinated by the monoprotonated 4N ligand in a tridentate fashion and the remaining three sites of the octahedron are occupied by chloride ions. The DFT optimized octahedral geometries of , and contain iron(iii) with a high-spin (S = 5/2) ground state. The catecholate adducts [Fe(L)(DBC)](+), where H2DBC is 3,5-di-tert-butylcatechol, of all the complexes have been generated in situ in acetonitrile solution and their spectral and redox properties and dioxygenase activities have been studied. The DFT optimized geometries of the catecholate adducts [Fe()(DBC)](+), [Fe()(DBC)](+) and [Fe()(DBC)](+) have also been generated to illustrate the ability of the complexes to cleave H2DBC in the presence of molecular oxygen to afford varying amounts of intra- (I) and extradiol (E) cleavage products. The extradiol to intradiol product selectivity (E/I, 0.1-2.0) depends upon the asymmetry in bidentate coordination of catecholate, as determined by the stereoelectronic properties of the ligand donor functionalities. While the higher E/I value obtained for [Fe()(DBC)](+) is on account of the steric hindrance of the quinolyl moiety to coordination the lower value observed for [Fe()(DBC)](+) and [Fe()(DBC)](+) is on account of the electron

  7. Genetic polymorphisms of estrogen receptor alpha and catechol-O-methyltransferase genes in Turkish patients with familial prostate carcinoma

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    Ayfer Pazarbasi

    2013-01-01

    Full Text Available Objectives: Estrogen is one of the most crucial hormones participating in the proliferation and carcinogenesis of the prostate glands. Genetic polymorphisms in the estrogen metabolism pathway might be involved in the risk of prostate carcinoma development. We evaluated the association between genetic polymorphisms in estrogen receptor alpha (ESR1 and catechol-O-methyltransferase (COMT genes and the risk of developing familial prostate carcinoma. Materials and Methods: In this study, 34 cases with prostate carcinoma whose first-degree relatives had prostate carcinoma and 30 healthy age-matched male controls were enrolled. The genotypes of ESR1 and COMT genes were analyzed employing polymerase chain reaction-restriction fragment length polymorphism method. 34 cases with prostate carcinoma, whose first degree relatives had prostate carcinoma and 14 age-matched male controls were enrolled to analyze the genotype of these two genes. Results: Among control patients, the ESR1 PvuII genotypes of C/C, C/T and T/T were observed in 37%, 26% and 37%, respectively, whereas the C/C, C/T and T/T genotypes were observed in 18%, 41% and 41% of case patients, respectively. Among controls, the ESR1 PvuII allele frequencies of C and T were equally observed, whereas the C and T allele frequencies were observed in 38% and 62% of patients, respectively. Among ESR1 PvuII genotypes there were not any significant difference in terms of genotype (P = 0.199 and allele (P = 0.181 frequencies . Among controls, the ESR1 XbaI genotypes of G/G, G/A and A/A were observed in 33%, 37% and 33%, respectively, whereas the G/G, G/A and A/A genotypes were observed in 12%, 47% and 41% of patients, respectively. Among controls, the ESR1 XbaI allele frequencies of A and G were observed equally, respectively, whereas the A and G frequencies were observed in 65% and 35% of patients, respectively. Among ESR1 Χ baI, there was not any significant difference in terms of genotype (P = 0.111 and

  8. No association between chronic musculoskeletal complaints and Val158Met polymorphism in the Catechol-O-methyltransferase gene. The HUNT study

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    Stovner Lars

    2006-05-01

    Full Text Available Abstract Background The Catechol-O-methyltransferase (COMT gene contains a functional polymorphism, Val158Met, that has been found to influence human pain perception. In one study fibromyalgia was less likely among those with Val/Val genotype. Methods In the 1995–97 Nord-Trøndelag Health Study (HUNT, the association between Val/Met polymorphism at the COMT gene and chronic musculoskeletal complaints (MSCs was evaluated in a random sample of 3017 individuals. Results The distribution of the COMT Val158Met genotypes and alleles were similar between controls and the twelve different chronic MSCs groups. Even when the Met/Met and Val/Met genotypes were pooled, the distribution of the Val/Val genotype and other genotypes were similar between controls and the chronic MSCs groups. Conclusion In this population-based study, no significant association was found between Val/Met polymorphism at the COMT gene and chronic MSCs.

  9. No evidence of association between Catechol-O-Methyltransferase (COMT Val158Met genotype and performance on neuropsychological tasks in children with ADHD: A case-control study

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    O'Donovan Michael C

    2004-06-01

    Full Text Available Abstract Background Several studies have suggested an association between the functional Val158Met polymorphism in the Catechol-O-Methyltransferase (COMT gene and neurocognitive performance. Two studies showed that subjects with the low activity Met allele performed better on the Wisconsin Card Sorting Test (WCST and another study found an effect on processing speed and attention. Methods We set out to examine the association between the Val158Met polymorphism and performance on neurocognitive tasks including those tapping working memory, attention and speed, impulsiveness and response inhibition in a sample of 124 children with ADHD. Task performance for each genotypic group was compared using analysis of variance. Results There was no evidence of association with performance on any of the neurocognitive tasks. Conclusions We conclude that Val158Met COMT genotype is not associated with neurocognitive performance in our sample.

  10. Design of Potent and Druglike Nonphenolic Inhibitors for Catechol O-Methyltransferase Derived from a Fragment Screening Approach Targeting the S-Adenosyl-l-methionine Pocket.

    Science.gov (United States)

    Lerner, Christian; Jakob-Roetne, Roland; Buettelmann, Bernd; Ehler, Andreas; Rudolph, Markus; Rodríguez Sarmiento, Rosa María

    2016-11-23

    A fragment screening approach designed to target specifically the S-adenosyl-l-methionine pocket of catechol O-methyl transferase allowed the identification of structurally related fragments of high ligand efficiency and with activity on the described orthogonal assays. By use of a reliable enzymatic assay together with X-ray crystallography as guidance, a series of fragment modifications revealed an SAR and, after several expansions, potent lead compounds could be obtained. For the first time nonphenolic and small low nanomolar potent, SAM competitive COMT inhibitors are reported. These compounds represent a novel series of potent COMT inhibitors that might be further optimized to new drugs useful for the treatment of Parkinson's disease, as adjuncts in levodopa based therapy, or for the treatment of schizophrenia.

  11. Characterization and Catalytic Activity of Titanium-containing Aluminum Phosphate Prepared by Sol-gel and Nonuniform Precipitation for O-Alkylation of Catechol with Ethanol

    Institute of Scientific and Technical Information of China (English)

    PAN Chun-liu; ZHANG Wen-xiang; LI Xue-mei; JIANG Da-zhen; WU Tong-hao

    2003-01-01

    Three titanium-containing aluminum phosphate catalysts with a general formula Al0.77Ti0.23PO4 were prepared by the sol-gel method at room temperature(APTS), and a nonuniform precipitation procedure at room temperature(APTR) and under reflux(APTF), respectively. The structural features and the surface properties of the three catalysts were determined by means of the physical adsorption of nitrogen at liquid N2 temperature, XRD, UV-Vis, NH3-TPD and IR of adsorbed pyridine. The vapor phase O-alkylation of catechol with ethanol over the prepared catalysts was studied. It was found that the activity and the selectivity of these catalysts are greatly dependent on the preparation method, and catalyst APTF shows the highest activity and selectivity. The characterization evidence indicates that the weak Brnsted acid sites were more effective for the reaction.

  12. Radiometric assay for phenylethanolamine N-methyltransferase and catechol O-methyltransferase in a single tissue sample: application to rat hypothalamic nuclei, pineal gland, and heart

    Energy Technology Data Exchange (ETDEWEB)

    Culman, J.; Torda, T.; Weise, V.K.

    1987-08-01

    A simple and highly sensitive method for simultaneous assay of phenylethanolamine N-methyltransferase (PNMT) and catechol O-methyltransferase (COMT) is described. These enzymes are determined in a single tissue homogenate using S-(methyl-/sup 3/H) adenosyl-L-methionine as methyl donor and sequentially incubating with the substrates phenylethanolamine and epinephrine. The radioactive products of the enzymatic reactions, N-methylphenylethanolamine and metanephrine, are extracted and then separated by thin-layer chromatography. The identity of the reaction products has been established chromatographically and the conditions for both enzymatic reactions in the assay procedure have been defined. Measurement of PNMT activity in the rat pineal gland or in minute fragments of other tissues (e.g., brain nuclei) has not been possible using previously described methods. Activities of PNMT and COMT in the rat pineal gland, various hypothalamic nuclei, and the auricular and ventricular myocardia are herein reported.

  13. The Role of the Catechol-o-methyltransferase (COMT) Gene Val158Met in Aggressive Behavior, A Review of Genetic Studies

    Science.gov (United States)

    Qayyum, Arqam; Zai, Clement C.; Hirata, Yuko; Tiwari, Arun K.; Cheema, Sheraz; Nowrouzi, Behdin; Beitchman, Joseph H.; Kennedy, James L.

    2015-01-01

    Aggressive behaviors have become a major public health problem, and early-onset aggression can lead to outcomes such as substance abuse, antisocial personality disorder among other issues. In recent years, there has been an increase in research in the molecular and genetic underpinnings of aggressive behavior, and one of the candidate genes codes for the catechol-O-methyltransferase (COMT). COMT is involved in catabolizing catecholamines such as dopamine. These neurotransmitters appear to be involved in regulating mood which can contribute to aggression. The most common gene variant studied in the COMT gene is the Valine (Val) to Methionine (Met) substitution at codon 158. We will be reviewing the current literature on this gene variant in aggressive behavior. PMID:26630958

  14. Association of the Catechol O-Methyltransferase Val158-Met Polymorphism and Reduced Interference Control in Korean Children with Attention-Deficit Hyperactivity Disorder

    Science.gov (United States)

    Park, Subin; Park, Jong-Eun; Yoo, Hee Jeong; Kim, Jae-Won; Cheong, Jae Hoon; Han, Doug Hyun; Kim, Yeni

    2015-01-01

    Objective We tested for association of the catechol-O-methyltransferase (COMT) Val158-Met (rs4680) polymorphism with attention-deficit hyperactivity disorder (ADHD) using family-based test in Korean trios. Methods A total of 181 subjects with ADHD along with both of their biological parents were recruited from University Hospitals in Korea. We performed a transmission disequilibrium test (TDT) on 181 trios. Results In the TDT, we found the over-transmission of the Val allele in children with ADHD (χ2=4.21, p=0.040). Conclusion These results suggest that the COMT Val158-Met polymorphism is associated with ADHD among the Korean population. However, this study must be replicated in larger populations. PMID:26508970

  15. Quantitative Determination and Comparison of the Surface Binding of Phosphonic Acid, Carboxylic Acid, and Catechol Ligands on TiO2 Nanoparticles.

    Science.gov (United States)

    Zeininger, Lukas; Portilla, Luis; Halik, Marcus; Hirsch, Andreas

    2016-09-12

    The adsorption, desorption, co-adsorption, and exchange behavior of phosphonic acid, carboxylic acid, and catechol derivatives on the surface of titanium oxide (anatase) nanoparticles are investigated. Thermogravimetric analysis provides a facile and fast-track quantitative determination of the wet-chemical monolayer adsorption constants and grafting densities of ten adsorbates, all under neutral pH conditions. This characterization protocol allows straightforward quantification of the relevant thermodynamic data of ligand adsorption and a comparison of ligand adsorption strengths. The reported procedure is proposed as a universal tool and it should be applicable to many other colloidal metal oxide materials. Moreover, the determined values for the adsorption constants and the monolayer grafting densities provide a toolbox for the assessment of the adsorbates' behavior in desorption, exchange, and co-adsorption equilibria. This versatile evaluation procedure will help to identify optimal monolayer-surface combinations and to evaluate critical parameters, such as monolayer robustness, ligand exchange rates, or targeted mixed assembly of functionalities.

  16. 4-Nitrocatecholato iron(III) complexes of 2-aminomethyl pyridine-based bis(phenol) amine as structural models for catechol-bound 3,4-PCD

    Science.gov (United States)

    Safaei, Elham; Heidari, Sima; Wojtczak, Andrzej; Cotič, Patricia; Kozakiewicz, Anna

    2016-02-01

    Two nitrocatecholato(HNC) iron(III) complexes, [FeLAMPX(H-NC)]. NEt3, of the tetradendate ligand (2-aminomethylpyridine)bis(2-pyridylmethyl)amine (H2LAMPX) were synthesized and structurally characterized. These structural models for catechol-bound 3,4-PCD were characterized by IR, UV-vis, elemental analysis and magnetic measurements. X-ray crystallography studies revealed that in both complexes the iron(III) centers are distorted octahedral and coordinated by two phenolate oxygen's, two amine nitrogen's of the ligand and mono anionic nitrocatecholate group (HNC). The variable-temperature magnetic susceptibility studies revealed paramagnetic properties of the reported complexes. The effective magnetic moments for the complexes lie between 5.3 and 5.4 BM correspond to the reported values for high spin Fe(III) center. The ligand-centered oxidation and metal-centered reduction of complexes was studies using cyclic voltammetry (CV) technique.

  17. The simultaneous electrochemical detection of catechol and hydroquinone with [Cu(Sal-β-Ala)(3,5-DMPz)2]/SWCNTs/GCE.

    Science.gov (United States)

    Alshahrani, Lina Abdullah; Li, Xi; Luo, Hui; Yang, Linlin; Wang, Mengmeng; Yan, Songling; Liu, Peng; Yang, Yuqin; Li, Quanhua

    2014-11-25

    A glassy carbon electrode was modified with a copper(II) complex [Cu(Sal-β-Ala) (3,5-DMPz)2] (Sal = salicylaldehyde, β-Ala = β-alanine, 3,5-DMPz = 3,5-dimethylpyrazole) and single-walled carbon nanotubes (SWCNTs). The modified electrode was used to detect catechol (CT) and hydroquinone (HQ) and exhibited good electrocatalytic activities toward the oxidation of CT and HQ. The peak currents were linear with the CT and HQ concentrations over the range of 5-215 μmol·L(-1) and 5-370 μmol·L(-1) with corresponding detection limits of 3.5 μmol·L(-1) and 1.46 μmol·L(-1) (S/N = 3) respectively. Moreover, the modified electrode exhibited good sensitivity, stability and reproducibility for the determination of CT and HQ, indicating the promising applications of the modified electrode in real sample analysis.

  18. Physico-chemical characterization of SOA derived from catechol and guaiacol – a model substance for the aromatic fraction of atmospheric HULIS

    Directory of Open Access Journals (Sweden)

    K. Whitmore

    2011-01-01

    Full Text Available Secondary organic aerosol (SOA was produced from the aromatic precursors catechol and guaiacol by reaction with ozone in the presence and absence of simulated sunlight and humidity and investigated for its properties as a proxy for HUmic-LIke Substances (HULIS. Beside a small particle size, a relatively low molecular weight and typical optical features in the UV/VIS spectral range, HULIS contain a typical aromatic and/or olefinic chemical structure and highly oxidized functional groups within a high chemical diversity. Various methods were used to characterize the secondary organic aerosols obtained: Fourier transform infrared spectroscopy (FTIR demonstrated the formation of several carbonyl containing functional groups as well as structural and functional differences between aerosols formed at different environmental conditions. UV/VIS spectroscopy of filter samples showed that the particulate matter absorbs far into the visible range up to more than 500 nm. Ultrahigh resolved mass spectroscopy (ICR-FT/MS determined O/C-ratios between 0.3 and 1 and observed m/z ratios between 200 and 450 to be most abundant. Temperature-programmed-pyrolysis mass spectroscopy (TPP-MS identified carboxylic acids and lactones/esters as major functional groups. Particle sizing using a condensation-nucleus-counter and differential-mobility-particle-sizer (CNC/DMPS monitored the formation of small particles during the SOA formation process. Particle imaging, using field-emission-gun scanning electron microscopy (FEG-SEM, showed spherical particles, forming clusters and chains. We conclude that catechol and guaiacol are appropriate precursors for studies of the processing of aromatic SOA with atmospheric HULIS properties on the laboratory scale.

  19. THE PRODUCTION OF CATECHOL THROUGH DIRECT OXIDATION OF PHENOL%H2O2直接氧化苯酚制邻苯二酚

    Institute of Scientific and Technical Information of China (English)

    张淳; 张赋; 曹贵平; 朱中南

    2000-01-01

    综述了重要的精细化工产品邻苯二酚的各个生产工艺,着重叙述了在催化剂作用下用双氧水直接氧化苯酚制备邻苯二酚的几个代表性的工艺。目前研究工作的重点在于双氧水氧化体系的催化剂制备和改进,以期进一步提高苯酚的转化率,抑制焦油的生成。同时指出该体系的分析方法需进一步完善,反应和分离的过程研究工作也需加强,以加快我国的苯酚羟化技术的工业化进程。%Each technology for the important fine product-catechol was reviewed. The emphases were on several kinds of representative technology where catechol was produced through direct oxidation of phenol by hydrogen peroxide under catalysts. The catalysts used were very important, very many research organizations over the world were devoting themselves to the study of catalysts to increase the conversion of phenol and to restrain the production of tars. The analysis method for these systems must be perfected. The processes for reaction and separation must be studied to quicken the industrialization.

  20. The Catechol-O-Methyltransferase Val158Met Polymorphism Contributes to the Risk of Breast Cancer in the Chinese Population: An Updated Meta-Analysis

    Science.gov (United States)

    Wan, Guo-Xing; Cao, Yu-Wen; Li, Wen-Qin; Li, Yu-Cong; Li, Feng

    2014-01-01

    Purpose Catechol-O-methyltransferase (COMT) enzyme plays a central role in estrogen-induced carcinogenesis. Emerging evidence from association studies has revealed that the functional Val158Met polymorphism (rs4680 G>A) of the Catechol-O-methyltransferase gene (COMT) has been implicated in susceptibility to breast cancer in the Chinese population, while results of individual published studies remain inconclusive and inconsistent. To assess this association in the Chinese population, a meta-analysis was performed. Methods Eligible studies were searched on MEDLINE, Embase, Cochrane Library, China National Knowledge Infrastructure, and the Chinese Biomedicine Database. Odds ratios (ORs) with their corresponding 95% confidence intervals (CIs) were pooled to assess the association between COMT polymorphisms and the risk of breast cancer using RevMan 5.2 and Stata 12.0 software. Results The meta-analysis included 14 eligible studies, with a total of 4,626 breast cancer cases and 5,637 controls. Overall, the COMT Val158Met polymorphism (rs4680 G>A) was significantly associated with an increased risk of breast cancer in several genetic models (A/A vs. G/G: OR, 1.59, 95% CI, 1.12-2.27; A/A vs. G/A+G/G: OR, 1.62, 95% CI, 1.14-2.29; A vs. G: OR, 1.15, 95% CI, 1.00-1.32), and a subgroup analysis according to menopausal status showed that this association was especially evident among premenopausal Chinese women (A/A vs. G/G: OR, 1.87, 95% CI, 0.99-3.54; A/A vs. G/A+G/G: OR, 1.94, 95% CI, 1.03-3.63). Conclusion The results of this meta-analysis indicated that COMT Val158Met variants contribute to breast cancer susceptibility in the Chinese population, particularly among premenopausal women. PMID:25013436

  1. Discrimination and simultaneous determination of hydroquinone and catechol by tunable polymerization of imidazolium-based ionic liquid on multi-walled carbon nanotube surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Xun; Gao, Weiwei; Zhou, Shenghai; Shi, Hongyan; Huang, Hao; Song, Wenbo, E-mail: wbsong@jlu.edu.cn

    2013-12-17

    Graphical abstract: -- Highlights: •Tunable free radical polymerization of ionic liquid on MWCNT surfaces. •Discrimination of hydroquinone and catechol at functional electrochemical interface. •Excellent performances in simultaneous determination based on cation-π interaction. -- Abstract: Tunable polymerization of ionic liquid on the surfaces of multi-walled carbon nanotubes (MWCNTs) was achieved by a mild thermal-initiation-free radical reaction of 3-ethy-1-vinylimidazolium tetrafluoroborate in the presence of MWCNTs. Successful modification of polymeric ionic liquid (PIL) on MWCNTs surfaces (PIL-MWCNTs) was demonstrated by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis and X-ray photoelectron spectroscopy. The resulting PIL-MWCNTs possessed unique features of high dispersity in aqueous solution and tunable thickness of PIL layer, due to positive imidazole groups along PIL chains and controllable ionic liquid polymerization by tuning the ratio of precursor. Based on cation-π interaction between the positive imidazole groups on PIL-MWCNTs surface and hydroquinone (HQ) or catechol (CC), excellent discrimination ability toward HQ and CC and improved simultaneous detection performance were achieved. The linear range for HQ and CC were 1.0 × 10{sup −6} to 5.0 × 10{sup −4} M and 1.0 × 10{sup −6} to 4.0 × 10{sup −4} M, respectively. The detection limit for HQ was 4.0 × 10{sup −7} M and for CC 1.7 × 10{sup −7} M (S/N = 3), correspondingly.

  2. Global kinetic rate parameters for the formation of polycyclic aromatic hydrocarbons from the pyrolyis of catechol, a model compound representative of solid fuel moieties

    Energy Technology Data Exchange (ETDEWEB)

    E.B. Ledesma; N.D. Marsh; A.K. Sandrowitz; M.J. Wornat [Princeton University, Princeton, NJ (United States). Department of Mechanical and Aerospace Engineering

    2002-12-01

    To obtain kinetic parameters on PAH formation relevant to solid fuels combustion, pyrolysis experiments have been conducted with catechol, a model fuel representing entities in coal and biomass. Catechol pyrolysis experiments were performed in a tubular-flow reactor at temperatures of 500-1000{sup o}C and at a residence time of 0.4 s. PAH products were identified and quantified by high-pressure liquid chromatography with ultraviolet-visible diode-array detection and by gas chromatography with flame ionization and mass spectrometric detection. A pseudo-unimolecular reaction kinetic model was used to model the experimental yield/temperature data of 15 individual aromatics and of combinations of PAH grouped by structural class and ring-number. The modeling of the individual species' yields showed that the pseudo-unimolecular model agreed very well with the experimental data. E{sub a} values ranged from 50 to 110 kcal mol{sup -1}, generally increasing as the size of the aromatic product increased from one to five aromatic rings. The pseudo-unimolecular model also performed well in modeling the experimental yields of PAH grouped by structural class and ring number. The global kinetic analysis results for PAH grouped by ring number revealed that E{sub a} values increased in the following order: 2-ring {lt} 3-ring {lt} 4-ring {lt} 5-ring {lt} 6-ring. Their yields followed the reverse order: 2-ring {lt} 3-ring {lt} 4-ring {lt} 5-ring {lt} 6-ring. These trends of increasing E{sub a} and decreasing yield, as ring number is increased, are consistent with a mechanism for PAH growth involving successive ring buildup reactions. 39 refs., 6 figs., 3 tabs.

  3. Physico-chemical characterization of secondary organic aerosol derived from catechol and guaiacol as a model substance for atmospheric humic-like substances

    Directory of Open Access Journals (Sweden)

    J. Ofner

    2010-07-01

    Full Text Available Secondary organic aerosol was produced from the aromatic precursors catechol and guaiacol by reaction with ozone in the presence and absence of simulated sunlight and humidity and investigated for its properties as a proxy for humic-like substances (HULIS. Beside a small particle size, a relatively low molecular weight and typical optical features in the UV/VIS spectral range, HULIS contain a typical aromatic and/or olefinic chemical structure and highly oxidized functional groups within a high chemical diversity. Various methods were used to characterize the secondary organic aerosols obtained: Fourier transform infrared spectroscopy (FTIR demonstrated the formation of different carbonyl containing functional groups as well as structural and functional differences between aerosols formed at different environmental conditions. UV/VIS spectroscopy of filter samples showed that the particulate matter absorbs far into the visible range up to more than 500 nm. Ultrahigh resolved mass spectroscopy (ICR-FT/MS determined O/C-ratios between 0.3 and 1 and main molecular weights between 200 and 500 Da. Temperature-programmed-pyrolysis mass spectroscopy identified carboxylic acids and lactones as major functional groups. Particle sizing using CNC-DMPS demonstrated the formation of small particles during a secondary organic aerosol formation process. Particle imaging using field-emission-gun scanning electron microscopy (FEG-SEM showed spherical particles, forming clusters and chains. Hence, secondary organic aerosols from catechol and guaiacol are appropriate model substances for studies of the processing of aromatic secondary organic aerosols and atmospheric HULIS on the laboratory scale.

  4. The role of the catecholic and the electrophilic moieties of caffeic acid in Nrf2/Keap1 pathway activation in ovarian carcinoma cell lines.

    Science.gov (United States)

    Sirota, R; Gibson, D; Kohen, R

    2015-01-01

    In recent years, numerous studies have demonstrated the health benefits of polyphenols. A major portion of polyphenols in western diet are derived from coffee, which is one of the most consumed beverages in the world. It has been shown that many polyphenols gain their beneficial properties (e.g. cancer prevention) through the activation of the Nrf2/Keap1 pathway as well as their direct antioxidant activity. However, activation of Nrf2 in cancer cells might lead to resistance towards therapy through induction of phase II enzymes. In the present work we hypothesize that caffeic acid (CA), a coffee polyphenol, might act as an electrophile in addition to its nucleophilic properties and is capable of inducing the Nrf2/EpRE pathway in cancer cells. The results indicate that CA induces Nrf2 translocation into the nucleus and consequently its transcription. It has been demonstrated that generated hydrogen peroxide is involved in the induction process. It has also been found that this process is induced predominantly via the double bond in CA (Michael acceptor). However, surprisingly the presence of both nucleophilic and electrophilic moieties in CA resulted in a synergetic activation of Nrf2 and phase II enzymes. We also found that CA possesses a dual activity, although inducing GSTP1 and GSR, it inhibiting their enzymatic activity. In conclusion, the mechanism of induction of Nrf2 pathway and phase II enzymes by CA has been elucidated. The electrophilic moiety in CA is essential for the oxidation of the Keap1 protein. It should be noted that while the nucleophilic moiety (the catechol/quinone moiety) can provide scavenging ability, it cannot contribute directly to Nrf2 induction. It was found that this process may be induced by H2O2 produced by the catechol group. On the whole, it appears that CA might play a major role in the cancer cells by enhancing their resistance to treatment.

  5. The determination of catechol at single walled carbon nanotube-graphene oxide modified electrode%单壁碳纳米管-氧化石墨烯复合修饰电极测定邻苯二酚

    Institute of Scientific and Technical Information of China (English)

    刘小花; 白海鑫; 王瑾

    2015-01-01

    制备了用于测定邻苯二酚的单壁碳纳米管‐氧化石墨烯复合修饰玻碳电极.用循环伏安法研究了邻苯二酚在该电极上的电化学行为.结果表明,该修饰电极对邻苯二酚具有良好的电催化性能.在最佳实验条件下,采用差分脉冲伏安法对邻苯二酚进行了测定,其氧化峰电流与邻苯二酚浓度在2×10-6~1×10-4 mol/L 范围内呈线性关系,相关系数为0.9962,检出限为4×10-7 mol/L .该电极具有良好的重现性,用于模拟废水中邻苯二酚的测定结果令人满意.%A single walled carbon nanotube‐graphene oxide/GCE (glassy carbon electrode) elec‐trode was prepared to determine catechol .The electrochemical behavior of catechol on the mod‐ified electrode was investigated using cyclic voltammetry .The experimental results show that the modified electrode has good catalytical ability to catechol .Under the optimum experimental conditions ,the catechol was determined by differential pulse voltammetry .The oxidation peak current and the concentration of catechol show good linear relationship in the range of 2 × 10 - 6- 1 × 10 - 4 mol/L .The correlation coefficient is 0 .996 2 and the detection limit is 4 × 10 - 7 mol/L .The electrode showed good repeatability and was used to determine catechol in artificial wastewater with satisfactory results .

  6. 4-nitrocatechol as a probe of a Mn(II)-dependent extradiol-cleaving catechol dioxygenase (MndD): comparison with relevant Fe(II) and Mn(II) model complexes.

    Science.gov (United States)

    Reynolds, Mark F; Costas, Miquel; Ito, Masami; Jo, Du-Hwan; Tipton, A Alex; Whiting, Adam K; Que, Lawrence

    2003-02-01

    Mn(II)-dependent 3,4-dihydroxyphenylacetate 2,3-dioxygenase (MndD) is an extradiol-cleaving catechol dioxygenase from Arthrobacter globiformis that has 82% sequence identity to and cleaves the same substrate (3,4-dihydroxyphenylacetic acid) as Fe(II)-dependent 3,4-dihydroxyphenylacetate 2,3-dioxygenase (HPCD) from Brevibacterium fuscum. We have observed that MndD binds the chromophoric 4-nitrocatechol (4-NCH(2)) substrate as a dianion and cleaves it extremely slowly, in contrast to the Fe(II)-dependent enzymes which bind 4-NCH(2) mostly as a monoanion and cleave 4-NCH(2) 4-5 orders of magnitude faster. These results suggest that the monoanionic binding state of 4-NC is essential for extradiol cleavage. In order to address the differences in 4-NCH(2) binding to these enzymes, we synthesized and characterized the first mononuclear monoanionic and dianionic Mn(II)-(4-NC) model complexes as well as their Fe(II)-(4-NC) analogs. The structures of [(6-Me(2)-bpmcn)Fe(II)(4-NCH)](+), [(6-Me(3)-TPA)Mn(II)(DBCH)](+), and [(6-Me(2)-bpmcn)Mn(II)(4-NCH)](+) reveal that the monoanionic catecholate is bound in an asymmetric fashion (Delta r(metal-O(catecholate))=0.25-0.35 A), as found in the crystal structures of the E(.)S complexes of extradiol-cleaving catechol dioxygenases. Acid-base titrations of [(L)M(II)(4-NCH)](+) complexes in aprotic solvents show that the p K(a) of the second catecholate proton of 4-NCH bound to the metal center is half a p K(a) unit higher for the Mn(II) complexes than for the Fe(II) complexes. These results are in line with the Lewis acidities of the two divalent metal ions but are the opposite of the trend observed for 4-NCH(2) binding to the Mn(II)- and Fe(II)-catechol dioxygenases. These results suggest that the MndD active site decreases the second p K(a) of the bound 4-NCH(2) relative to the HPCD active site.

  7. Positron emission tomography in drug evaluation: Influence of three different catechol-O-methyltransferase inhibitors on metabolism of [NCA] 6-[{sup 18}F]fluoro-l-dopa in Rhesus monkey

    Energy Technology Data Exchange (ETDEWEB)

    Guenther, I.; Psylla, M.; Reddy, G.N.; Antonini, A.; Vontobel, P.; Reist, H.W.; Zollinger, A.; Nickles, R.J.; Beer, H.-F.; Schubiger, P.A.; Leenders, K.L

    1995-10-01

    We compared the influence of three different catechol-O-methyltransferase (COMT) inhibitors (CGP 28014, OR-611 and Ro 40-7592) on the metabolism of no-carrier-added (NCA) 6-[{sup 18}F]fluoro-l-dopa (6-FDOPA) in one Rhesus monkey. All three COMT inhibitors improved 6-FDOPA availability in plasma, increased the specific uptake in the brain and thus improved 6-FDOPA uptake measurements using positron emission tomography (PET). Best results were obtained with Ro 40-7592.

  8. Preparation of Co-Ni/Carbon Fiber Sensing Electrode and Determination of Catechol%钴镍/碳纤维传感电极的制备及其对邻苯二酚含量的测定

    Institute of Scientific and Technical Information of China (English)

    杨池; 张丹; 翁凌燕; 陶慧敏; 姚玲燕

    2015-01-01

    以钴镍盐为前驱体,采用溶胶-凝胶法在碳纤维(CF)上原位制备了钴镍纳米材料 Co-Ni/CF,采用电化学方法研究了邻苯二酚在 Co-Ni/CF 电极上的电化学性能。结果表明,Co-Ni/CF 电极对邻苯二酚具有良好的电催化特性,邻苯二酚浓度在1~3 mmol·L-1范围内与还原峰电流呈良好的线性关系,相关系数为0.99239,检出限为1.9×10-8 mol ·L-1,该方法具有灵敏度高、线性范围宽、稳定性好等特点,可用于邻苯二酚含量的测定。%Using cobalt salt and nickel salt as precursors,Co-Ni/carbon fiber nanomaterials were prepared in-situ by sol-gel method.The electrochemical properties of catechol on Co-Ni/CF electrode were studied.Re-sults showed that Co-Ni/CF electrode had excellent electrocatalytic characteristics to catechol,and the peak cur-rent increased linearly with the concentration of catechol in the range of 1~3 mmol·L-1 (R 2=0.99239)with a detection limit of 1.9 × 10-8 mol·L-1 .The method had good sensitivity,stability and reproducibility,with a broad linear range,and could be used for determination of catechol content.

  9. Determination of Catechol Based on Carbon Nanotube Modified Glassy Carbon Electrode%碳纳米管修饰玻碳电极测定邻苯二酚的研究

    Institute of Scientific and Technical Information of China (English)

    崔艳萍; 王卫星; 王小龙

    2011-01-01

    文章借助循环伏安法(CV)研究了邻二苯酚(CAT)在碳纳米管修饰玻碳电极(CNTs/GCE)表面的电催化氧化行为.试验结果表明:CNTs/GCE对邻二苯酚的氧化过程表现出良好的催化活性,其响应峰电流与裸GCE相比增加了10倍以上;在最佳响应条件下,在0.25~2.0 mmol/L的浓度范围内,邻苯二酚的催化氧化峰电流与浓度呈良好的线性关系;并对模拟废水中的邻苯二酚进行了回收试验.%Carbon nanotubes (CNTs) were loaded on the glassy carbon electrode to prepare carbon nanotube modified glassy carbon electrode (CNTs/GCE). And the electrocatalytic oxidation behavior of catechol was investigated on this modified electrode by cyclic voltammetry (CV) of the electrochemical methods. Results show that good electrocatalytic activity for catechol oxidation could be observed at CNTs/GCE. Compared with bare GCE, the response peak current of CNTs/GCE had an increase of more than lOtimes. Under the optimal condition of response, the oxidation peak current were increased linear with the concentrations of catechol at the range 0.25-2.0 mmol/L. And the recovery test of catechol in simulating wastewater was satisfactory.

  10. Detection of Catechol by TiO2-graphene-modified Glassy Carbon Electrode%TiO2-石墨烯修饰玻碳电极测定邻苯二酚

    Institute of Scientific and Technical Information of China (English)

    熊小琴; 王兰; 张丽媛

    2011-01-01

    制备了Ti02 -石墨烯修饰玻碳电极,利用循环伏安法(CV)和差分脉冲伏安法(DPV)研究了邻苯二酚在该修饰电极的电化学行为.结果表明:在pH值为6.0的磷酸盐缓冲液(PBS)中,该修饰电校对邻苯二酚具有良好的电催化作用.邻苯二酚氧化峰电流与其浓度(1.0×10-6~ 1.0×10-5 mol/L)呈现良好的线性关系,线性相关系数为0.993,检出限为1×10-7 mol/L.该电极显著提高了检测的灵敏度,并表现出良好的选择性和重现性.%novel TiO2-graphene-modified glassy carbon electrode (TiO2-Gr/GCE) was fabricated. The electrochemical behaviors of catechol at the modified electrode were studied by cyclic voltammetry ( CV) and differential pulse voltammetry ( DPV). In pH 6.0 phosphate buffer solution ( PBS) , the composite film showed excellent electrocatalytic activity for the redox of catechol. The results of DPV indicated that the oxidation peak currents was linear with catechol concentrations in the range of 1.0 × 10 -6 mol/L to 1. 0 × 10 -5 mol/L. The detection limit of catechol is 1.0 × 10 -7 mol/L (S/iV = 3). This modified CCE showed good sensitivity and selectivity and reproducibility.

  11. Mononuclear non-heme iron(III) complexes of linear and tripodal tridentate ligands as functional models for catechol dioxygenases: Effect of -alkyl substitution on regioselectivity and reaction rate

    Indian Academy of Sciences (India)

    Mallayan Palaniandavar; Kusalendiran Visvaganesan

    2011-03-01

    Catechol dioxygenases are responsible for the last step in the biodegradation of aromatic molecules in the environment. The iron(II) active site in the extradiol-cleaving enzymes cleaves the C-C bond adjacent to the hydroxyl group, while the iron(III) active site in the intradiol-cleaving enzymes cleaves the C-C bond in between two hydroxyl groups. A series of mononuclear iron(III) complexes of the type [Fe(L)Cl3], where L is the linear -alkyl substituted bis(pyrid-2-ylmethyl)amine, -alkyl substituted -(pyrid-2-ylmethyl)ethylenediamine, linear tridentate 3N ligands containing imidazolyl moieties and tripodal ligands containing pyrazolyl moieties have been isolated and studied as structural and functional models for catechol dioxygenase enzymes. All the complexes catalyse the cleavage of catechols using molecular oxygen to afford both intra- and extradiol cleavage products. The rate of oxygenation depends on the solvent and the Lewis acidity of iron(III) center as modified by the sterically demanding -alkyl groups. Also, our studies reveal that stereo-electronic factors like the Lewis acidity of the iron(III) center and the steric demand of ligands, as regulated by the -alkyl substituents, determine the regioselectivity and the rate of dioxygenation. In sharp contrast to all these complexes, the pyrazole-containing tripodal ligand complexes yield mainly the oxidized product benzoquinone.

  12. The genes coding for the conversion of carbazole to catechol are flanked by IS6100 elements in Sphingomonas sp. strain XLDN2-5.

    Directory of Open Access Journals (Sweden)

    Zhonghui Gai

    Full Text Available BACKGROUND: Carbazole is a recalcitrant compound with a dioxin-like structure and possesses mutagenic and toxic activities. Bacteria respond to a xenobiotic by recruiting exogenous genes to establish a pathway to degrade the xenobiotic, which is necessary for their adaptation and survival. Usually, this process is mediated by mobile genetic elements such as plasmids, transposons, and insertion sequences. FINDINGS: The genes encoding the enzymes responsible for the degradation of carbazole to catechol via anthranilate were cloned, sequenced, and characterized from a carbazole-degrading Sphingomonas sp. strain XLDN2-5. The car gene cluster (carRAaBaBbCAc and fdr gene were accompanied on both sides by two copies of IS6100 elements, and organized as IS6100::ISSsp1-ORF1-carRAaBaBbCAc-ORF8-IS6100-fdr-IS6100. Carbazole was converted by carbazole 1,9a-dioxygenase (CARDO, CarAaAcFdr, meta-cleavage enzyme (CarBaBb, and hydrolase (CarC to anthranilate and 2-hydroxypenta-2,4-dienoate. The fdr gene encoded a novel ferredoxin reductase whose absence resulted in lower transformation activity of carbazole by CarAa and CarAc. The ant gene cluster (antRAcAdAbAa which was involved in the conversion of anthranilate to catechol was also sandwiched between two IS6100 elements as IS6100-antRAcAdAbAa-IS6100. Anthranilate 1,2-dioxygenase (ANTDO was composed of a reductase (AntAa, a ferredoxin (AntAb, and a two-subunit terminal oxygenase (AntAcAd. Reverse transcription-PCR results suggested that carAaBaBbCAc gene cluster, fdr, and antRAcAdAbAa gene cluster were induced when strain XLDN2-5 was exposed to carbazole. Expression of both CARDO and ANTDO in Escherichia coli required the presence of the natural reductases for full enzymatic activity. CONCLUSIONS/SIGNIFICANCE: We predict that IS6100 might play an important role in the establishment of carbazole-degrading pathway, which endows the host to adapt to novel compounds in the environment. The organization of the car

  13. Synthesis and electrochemical and spectroscopic properties of a series of binuclear and trinuclear ruthenium and palladium complexes based on a new bridging ligand containing terpyridyl and catechol binding sites

    Energy Technology Data Exchange (ETDEWEB)

    Whittle, B.; Everest, N.S.; Howard, C.; Ward, M.D. [Univ. of Bristol (United Kingdom)

    1995-04-12

    The ligand 4{prime}-(3,4-dimethoxyphenyl)-2,2{prime}:6{prime},2{double_prime}-terpyridine (L{sup 2}), containing a terpyridyl binding site and a masked catechol binding site, was prepared by a standard Kroehnke-type synthesis. From this the complexes [Ru(terpy)-(L{sup 2})][PF{sub 6}]{sub 2} (1) and [Ru(L{sup 2}){sub 2}][PF{sub 6}]{sub 2} (2), containing one and two dimethoxyphenyl substituents, were prepared: demethylation with BBr{sub 3} afforded [Ru(terpy)(H{sub 2}L{sup 1})][PF{sub 6}]{sub 2} (3) and [Ru(H{sub 2}L{sup 1}){sub 2}][PF{sub 6}]{sub 2} (4), respectively, which have one or two free catechol binding sites pendant from the [Ru(terpy){sub 2}]{sup 2+} core. Binuclear complexes (based on 3) and trinuclear complexes (based on 4) were then prepared by attachment of other metal fragments at the catechol sites. In [Ru(terpy)({mu}-L{sup 1})Ru(bipy){sub 2}][PF{sub 6}]{sub 3} (5) and [Ru({mu}-L{sup 1}){sub 2}(Ru(bipy){sub 2}){sub 2}][PF{sub 6}]{sub 4} (6) the pendant (Ru(bipy){sub 2}(O-O)){sup n+} sites (O-O = catecholate, n = 0; o-benzosemiquinone, n = 1; o-benzoquinone, n = 2) are redox active and may be reversibly interconverted between the three oxidation levels. In [Ru(terpy)({mu}-L{sup 1})Pd(bipy)][PF{sub 6}]{sub 2} (7), [Ru({mu}-L{sup 1}){sub 2}(Pd(bipy)){sub 2}][PF{sub 6}]{sub 2} (8), [Ru(terpy)({mu}-L{sup 1})Pd(4,4{prime}-{sup t}Bu{sub 2}-bipy)][PF{sub 6}]{sub 2} (9), and [Ru({mu}-L{sup 1}){sub 2}(Pd(4,4{prime}-{sup t}Bu{sub 2}-bipy)){sub 2}][PF{sub 6}]{sub 2} (10) the pendant (Pd(bipy)(catecholate)) fragments are known to be photocatalysts for production of {sup 1}O{sub 2} in their own right. Electrochemical and UV/vis studies were performed on all complexes and consistently indicate the presence of interactions between the components in 5-10. The EPR spectrum of 6 (which contains two semiquinone radicals) shows that the two spins are coupled by an exchange interaction.

  14. 石墨烯修饰电极同时测定邻苯二酚和对苯二酚%Simultaneous determination of catechol and hydroquinone in graphene modified electrode

    Institute of Scientific and Technical Information of China (English)

    万其进; 廖华玲; 刘义; 魏薇; 舒好; 杨年俊

    2013-01-01

    制备石墨烯玻碳修饰电极,进而采用循环伏安法、交流阻抗等电化学方法对该电极进行表征,研究该石墨烯修饰电极在邻苯二酚和对苯二酚上的电化学行为.结果表明,在石墨烯修饰电极上邻苯二酚的氧化峰电位和还原峰电位分别是270 mV和161 mV,对苯二酚氧化峰电位和还原峰电位分别是145mV和64 mV,由于邻苯二酚和对苯二酚的氧化峰电位大约相离125 mV,还原峰大约相离97 mV,因此适合同时检测邻苯二酚和对苯二酚.邻苯二酚和对苯二酚的浓度在5.0×10-6~1.0×10-4 mol/L范围内与峰电流分别呈良好的线性关系;且在8.0×10-5~1.0×10-3 mol/L范围能同时检测邻苯二酚和对苯二酚,邻苯二酚的检测限可达5.0×10-7 mol/L,对苯二酚的检测限可达1.0×10-7 mol/L.该石墨烯修饰电极可作为电化学传感器用于邻苯二酚和对苯二酚的含量同时测定及环境水体中实际样品的分析.%A novel graphene modified glassy carbon electrode was fabricated. The resulting substrates were characterized by Cyclic Voltammetry and EIS in [Fe (CN)6 ]3-/4- solution and showed the electrochemical behavior of catechol and hydroquinone on the graphene modified glassy carbon electrode. Experiment result shows that the catechol oxidation peak potential is 270 mV and reduction peak potential is 161 mV, and the hydroquinone oxidation peak potential is 145 mV and reduction peak potential is 64 mV on the graphene modified electrode, respectively. The oxidation peak potential distance is about 125 mV and the reduction peak potential distance is about 97 mV of catechol and hydroquinone which are suited for the simultaneous detection. Catechol and hydroquinone have good electrocatalytic activity on modified electrode and the peak currents of differential pulse voltammetry are liner to the catechol and hydroquinone over the range of 5. 0× 10-6 — 1. 0× 10~4 mol/L, respectively, and the graphene modified electrode can

  15. A novel Laccase Biosensor based on Laccase immobilized Graphene-Cellulose Microfiber Composite modified Screen-Printed Carbon Electrode for Sensitive Determination of Catechol

    Science.gov (United States)

    Palanisamy, Selvakumar; Ramaraj, Sayee Kannan; Chen, Shen-Ming; Yang, Thomas C. K.; Yi-Fan, Pan; Chen, Tse-Wei; Velusamy, Vijayalakshmi; Selvam, Sonadevi

    2017-01-01

    In the present work, we demonstrate the fabrication of laccase biosensor to detect the catechol (CC) using laccase immobilized on graphene-cellulose microfibers (GR-CMF) composite modified screen printed carbon electrode (SPCE). The direct electrochemical behavior of laccase was investigated using laccase immobilized different modified SPCEs, such as GR/SPCE, CMF/SPCE and GR-CMF/SPCE. Compared with laccase immobilized GR and CMF modified SPCEs, a well-defined redox couple of CuI/CuII for laccase was observed at laccase immobilized GR-CMF composite modified SPCE. Cyclic voltammetry results show that the as-prepared biosensor has 7 folds higher catalytic activity with lower oxidation potential towards CC than SPCE modified with GR-CMF composite. Under optimized conditions, amperometric i-t method was used for the quantification of CC, and the amperometric response of the biosensor was linear over the concertation of CC ranging from 0.2 to 209.7 μM. The sensitivity, response time and the detection limit of the biosensor for CC is 0.932 μMμA−1 cm−2, 2 s and 0.085 μM, respectively. The biosensor has high selectivity towards CC in the presence of potentially active biomolecules and phenolic compounds. The biosensor also accessed for the detection of CC in different water samples and shows good practicality with an appropriate repea. PMID:28117357

  16. Molecular, spectroscopic and thermal studies on catechol, 4,5-dibromocatechol, resorcinol, hydroquinone and 4-4‧-dihydroxybiphenyl derivatives armed with benzothiazole moieties

    Science.gov (United States)

    Alshargabi, Arwa; Yeap, Guan-Yeow; Mahmood, Wan Ahmad Kamil; Samikannu, Rakesh

    2013-05-01

    A new series of catechol, 4,5-dibromocatechol, resorcinol, hydroquinone and 4-4'-dihydroxybiphenyl derivatives possessing two benzothiazole moieties at respective positions of 1,2, 1,3, 1,4 and/or 4,4' has successfully been synthesized. The molecular structures were fully elucidated by spectroscopic techniques (1H NMR, 13C NMR and two dimensional COSY, HMBC, HMQC, DEPT-135 and DEPT-90). The connectivity study between the cause of using different core systems in the target compounds and the anisotropic behavior as inferred from phase transition temperature and relevant morphology studies has led to some unique features arising from this series. Compounds with ortho substituent exhibit enantiotropic N and SmA phases. The analogues containing resorcinol and 4,4'-disubstituentbiphenyl show enanotiotropic nematic behavior while the hydroquinone derivative induces the formation of monotropic nematogen. An extensive study to further substantiate the relationship between the stability of the nematic phase and associated transition temperatures due to different core systems is also reported.

  17. Convergent Mechanistic Features between the Structurally Diverse N- and O-Methyltransferases: Glycine N-Methyltransferase and Catechol O-Methyltransferase.

    Science.gov (United States)

    Zhang, Jianyu; Klinman, Judith P

    2016-07-27

    Although an enormous and still growing number of biologically diverse methyltransferases have been reported and identified, a comprehensive understanding of the enzymatic methyl transfer mechanism is still lacking. Glycine N-methyltransferase (GNMT), a member of the family that acts on small metabolites as the substrate, catalyzes methyl transfer from S-adenosyl-l-methionine (AdoMet) to glycine to form S-adenosyl-l-homocysteine and sarcosine. We report primary carbon ((12)C/(14)C) and secondary ((1)H3/(3)H3) kinetic isotope effects at the transferred methyl group, together with (1)H3/(3)H3 binding isotope effects for wild-type GNMT and a series of Tyr21 mutants. The data implicate a compaction effect in the methyl transfer step that is conferred by the protein structure. Furthermore, a remarkable similarity of properties is observed between GNMT and catechol O-methyltransferase, despite significant differences between these enzymes with regard to their active site structures and catalyzed reactions. We attribute these results to a catalytically relevant reduction in the methyl donor-acceptor distance that is dependent on a tyrosine side chain positioned behind the methyl-bearing sulfur of AdoMet.

  18. Catechol-O-methlytransferase inhibition alters pain and anxiety-related volitional behaviors through activation of β-adrenergic receptors in the rat

    Science.gov (United States)

    Kline, R. H.; Exposto, F. G.; O’Buckley, S. C.; Westlund, K. N.; Nackley, A. G.

    2015-01-01

    Reduced catechol-O-methyltransferase (COMT) activity resulting from genetic variation or pharmacological depletion results in enhanced pain perception in humans and nociceptive behaviors in animals. Using phasic mechanical and thermal reflex tests (e.g. von Frey, Hargreaves), recent studies show that acute COMT-dependent pain in rats is mediated by β-adrenergic receptors (βARs). In order to more closely mimic the characteristics of human chronic pain conditions associated with prolonged reductions in COMT, the present study sought to determine volitional pain-related and anxiety-like behavioral responses following sustained as well as acute COMT inhibition using an operant 10–45°C thermal place preference task and a light/dark preference test. In addition, we sought to evaluate the effects of sustained COMT inhibition on generalized body pain by measuring tactile sensory thresholds of the abdominal region. Results demonstrated that acute and sustained administration of the COMT inhibitor OR486 increased pain behavior in response to thermal heat. Further, sustained administration of OR486 increased anxiety behavior in response to bright light, as well as abdominal mechanosensation. Finally, all pain-related behaviors were blocked by the non-selective βAR antagonist propranolol. Collectively, these findings provide the first evidence that stimulation of ARs following acute or chronic COMT inhibition drives cognitive-affective behaviors associated with heightened pain that affects multiple body sites. PMID:25659347

  19. A new iron(III) complex of glycine derivative of amine-chloro substituted phenol ligand: Synthesis, characterization and catechol dioxygenase activity

    Science.gov (United States)

    Saberikia, Iraj; Safaei, Elham; Kowsari, Mohammad Hossein; Lee, Yong-Ill; Cotic, Patricia; Bruno, Giuseppe; Rudbari, Hadi Amiri

    2012-12-01

    A new iron(III) complex of the glycine derivative of amine-chloro substituted phenol ligand (H3LGDC) has been prepared and characterized by IR, 1H NMR, UV-Vis spectroscopic techniques, cyclic voltammetry, ESI-MS and magnetic susceptibility studies. X-ray analysis reveals that in iron complex of FeLGDC the iron(III) center has a distorted trigonal bipyramidal coordination sphere and is surrounded by an amine nitrogen, a carboxylate, a water and two phenolate oxygen atoms. The DFT calculations with the UB3LYP/6-311++G** level optimized structure of the complex are in good agreement with experimental X-ray structural data. The variable-temperature magnetic susceptibility indicates that FeLGDC is the paramagnetic high spin iron(III) complex. It has been shown that electrochemical oxidation of this complex is ligand-centered due to the oxidation of phenolate to the phenoxyl radicals. This enzyme mimic utilized molecular oxygen in carrying out the oxidative cleavage of catechols with complete conversion at room temperature.

  20. The quantification of hydroquinone, catechol, phenol, 3-methylcatechol, scopoletin, m+p-cresol and o-cresol in indoor air samples by high-performance liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Risner, C.H. (R.J. Reynolds Tobacco Co., Winston-Salem, NC (United States). Bowman Gray Technical Center)

    1993-01-01

    A high performance liquid chromatography (HPLC) method was developed for the quantification of the phenolic compounds hydroquinone, catechol, phenol, 3-methylcatechol, scopoletin, m+p-cresol and o-cresol in indoor air samples. Samples are collected on an 0.8 [mu]m pore size mixed cellulose ester membrane (MCEM) followed by a silica gel Sep-Pak. The MCEM is extracted and the SiOHSP is eluted with 1% acetic acid. The phenolic compounds were analyzed on a reverse-phase column with fluorescence detection at selected excitation and emission wavelengths specific to the compounds of interest. A mobile phase gradient of 1% HAc and 99% acetonitrile + 1% HAc is used. The method is reproducible with percent relative standard deviations ranging from 2.0 to 9.2 for the seven phenolic compounds. Percent recoveries are acceptable with the exception of scopoletin and p-cresol. A comparison of tobacco versus wood smoke show that amounts of these seven phenolic compounds vary widely with their source. A relatively short sampling time is required and the procedure is capable of detecting <0.3 [mu]g m[sup [minus]3] for all compounds with the exception of 3-methylcatechol with a detection limit of < 4.0 [mu]g m[sup [minus]3].

  1. Facile one-pot synthesis and application of nitrogen and sulfur-doped activated graphene in simultaneous electrochemical determination of hydroquinone and catechol.

    Science.gov (United States)

    Xiao, Lili; Yin, Jiao; Li, Yingchun; Yuan, Qunhui; Shen, Hangjia; Hu, Guangzhi; Gan, Wei

    2016-10-07

    Nitrogen (N) and sulfur (S) co-doped activated graphene (N,S-AGR) was prepared by the one-pot pyrolysis of a mixture of graphene oxide (GO), thiourea, and potassium hydroxide (KOH), where thiourea acts as the source of N and S dopants and KOH is the activator for porosity. N,S-AGR with a dopant abundance of 2.8 at% N and 2.3 at% S was then used as a high-activity electrocatalyst in the fabrication of an electrochemical sensor for simultaneous determination of dihydroxybenzene isomers, hydroquinone (HQ) and catechol (CC), in aqueous solution. Compared with the bare glassy carbon electrode (GCE), the electrodes modified with N,S-AGR showed enhanced electrochemical performance toward HQ and CC in both cyclic voltammetric (CV) and differential pulse voltammetric (DPV) measurements because of their enlarged surface area, enhanced electron-transfer rate and increased active sites. Compared with some recently reported electrochemical sensors based on graphene composites, the N,S-AGR modified electrode exhibits higher sensitivity, a much lower detection limit and a comparable linear range for the simultaneous determination of HQ and CC. Moreover, the proposed sensor is promising in practical application for the satisfactory recoveries obtained in real water sample analyses.

  2. The catechol-o-methyltransferase Val158Met polymorphism modulates the intrinsic functional network centrality of the parahippocampal cortex in healthy subjects

    Science.gov (United States)

    Zhang, Xiaolong; Li, Jin; Qin, Wen; Yu, Chunshui; Liu, Bing; Jiang, Tianzi

    2015-01-01

    The influence of catechol-o-methyltransferase (COMT) Val158Met on brain activation and functional connectivity has been widely reported. However, voxel-wise effects of this genotype on resting-state brain networks remain unclear. Here, we used resting-state fMRI and eigenvector centrality to examine the effects of COMT Val158Met genotypes on the connection patterns of the brain network and working memory (WM) in healthy, young Val/Val and Met carrier subjects. There were significant differences in the performance level on the 2-back WM task between the different COMT genotypes: Val/Val individuals exhibited a higher correct rate compared to the Met carriers. A two-sample t test was used to examine the differences in the eigenvector centrality maps, using age and gender as covariates of no interest, between the Val/Val and Met carriers. We found that the Val/Val individuals exhibited significantly higher eigenvector centrality compared to the Met carriers in the left parahippocampal cortex. Furthermore, a significantly positive correlation between the mean eigenvector centrality of the significant cluster and the correct rate of the 2-back WM task was observed. By using a voxel-wise data-driven method, our findings may provide plausible implications regarding individual differences in the genetic contribution of COMT Val158Met to the brain network and cognition. PMID:26054510

  3. Structure related effects of flavonoid aglycones on cell cycle progression of HepG2 cells: Metabolic activation of fisetin and quercetin by catechol-O-methyltransferase (COMT).

    Science.gov (United States)

    Poór, Miklós; Zrínyi, Zita; Kőszegi, Tamás

    2016-10-01

    Dietary flavonoids are abundant in the Plant Kingdom and they are extensively studied because of their manifold pharmacological activities. Recent studies highlighted that cell cycle arrest plays a key role in their antiproliferative effect in different tumor cells. However, structure-activity relationship of flavonoids is poorly characterized. In our study the influence of 18 flavonoid aglycones (as well as two metabolites) on cell cycle distribution was investigated. Since flavonoids are extensively metabolized by liver cells, HepG2 tumor cell line was applied, considering the potential metabolic activation/inactivation of flavonoids. Our major observations are the followings: (1) Among the tested compounds diosmetin, fisetin, apigenin, lutelin, and quercetin provoked spectacular extent of G2/M phase cell cycle arrest. (2) Inhibition of catechol-O-methyltransferase enzyme by entacapone decreased the antiproliferative effects of fisetin and quercetin. (3) Geraldol and isorhamnetin (3'-O-methylated metabolites of fisetin and quercetin, respectively) demonstrated significantly higher antiproliferative effect on HepG2 cells compared to the parent compounds. Based on these results, O-methylated flavonoid metabolites or their chemically modified derivatives may be suitable candidates of tumor therapy in the future.

  4. High quality draft genome sequence of Olivibacter sitiensis type strain (AW-6T), a diphenol degrader with genes involved in the catechol pathway

    Science.gov (United States)

    Ntougias, Spyridon; Lapidus, Alla; Han, James; Mavromatis, Konstantinos; Pati, Amrita; Chen, Amy; Klenk, Hans-Peter; Woyke, Tanja; Fasseas, Constantinos; Kyrpides, Nikos C.; Zervakis, Georgios I.

    2014-01-01

    Olivibacter sitiensis Ntougias et al. 2007 is a member of the family Sphingobacteriaceae, phylum Bacteroidetes. Members of the genus Olivibacter are phylogenetically diverse and of significant interest. They occur in diverse habitats, such as rhizosphere and contaminated soils, viscous wastes, composts, biofilter clean-up facilities on contaminated sites and cave environments, and they are involved in the degradation of complex and toxic compounds. Here we describe the features of O. sitiensis AW-6T, together with the permanent-draft genome sequence and annotation. The organism was sequenced under the Genomic Encyclopedia for Bacteria and Archaea (GEBA) project at the DOE Joint Genome Institute and is the first genome sequence of a species within the genus Olivibacter. The genome is 5,053,571 bp long and is comprised of 110 scaffolds with an average GC content of 44.61%. Of the 4,565 genes predicted, 4,501 were protein-coding genes and 64 were RNA genes. Most protein-coding genes (68.52%) were assigned to a putative function. The identification of 2-keto-4-pentenoate hydratase/2-oxohepta-3-ene-1,7-dioic acid hydratase-coding genes indicates involvement of this organism in the catechol catabolic pathway. In addition, genes encoding for β-1,4-xylanases and β-1,4-xylosidases reveal the xylanolytic action of O. sitiensis. PMID:25197463

  5. Age-Dependent Effects of Catechol-O-Methyltransferase (COMT) Gene Val158Met Polymorphism on Language Function in Developing Children.

    Science.gov (United States)

    Sugiura, Lisa; Toyota, Tomoko; Matsuba-Kurita, Hiroko; Iwayama, Yoshimi; Mazuka, Reiko; Yoshikawa, Takeo; Hagiwara, Hiroko

    2016-11-30

    The genetic basis controlling language development remains elusive. Previous studies of the catechol-O-methyltransferase (COMT) Val(158)Met genotype and cognition have focused on prefrontally guided executive functions involving dopamine. However, COMT may further influence posterior cortical regions implicated in language perception. We investigated whether COMT influences language ability and cortical language processing involving the posterior language regions in 246 children aged 6-10 years. We assessed language ability using a language test and cortical responses recorded during language processing using a word repetition task and functional near-infrared spectroscopy. The COMT genotype had significant effects on language performance and processing. Importantly, Met carriers outperformed Val homozygotes in language ability during the early elementary school years (6-8 years), whereas Val homozygotes exhibited significant language development during the later elementary school years. Both genotype groups exhibited equal language performance at approximately 10 years of age. Val homozygotes exhibited significantly less cortical activation compared with Met carriers during word processing, particularly at older ages. These findings regarding dopamine transmission efficacy may be explained by a hypothetical inverted U-shaped curve. Our findings indicate that the effects of the COMT genotype on language ability and cortical language processing may change in a narrow age window of 6-10 years.

  6. Brain catechol-O-methyltransferase (COMT) inhibition by tolcapone counteracts recognition memory deficits in normal and chronic phencyclidine-treated rats and in COMT-Val transgenic mice.

    Science.gov (United States)

    Detrait, Eric R; Carr, Greg V; Weinberger, Daniel R; Lamberty, Yves

    2016-08-01

    The critical involvement of dopamine in cognitive processes has been well established, suggesting that therapies targeting dopamine metabolism may alleviate cognitive dysfunction. Catechol-O-methyl transferase (COMT) is a catecholamine-degrading enzyme, the substrates of which include dopamine, epinephrine, and norepinephrine. The present work illustrates the potential therapeutic efficacy of COMT inhibition in alleviating cognitive impairment. A brain-penetrant COMT inhibitor, tolcapone, was tested in normal and phencyclidine-treated rats and COMT-Val transgenic mice. In a novel object recognition procedure, tolcapone counteracted a 24-h-dependent forgetting of a familiar object as well as phencyclidine-induced recognition deficits in the rats at doses ranging from 7.5 to 30 mg/kg. In contrast, entacapone, a COMT inhibitor that does not readily cross the blood-brain barrier, failed to show efficacy at doses up to 30 mg/kg. Tolcapone at a dose of 30 mg/kg also improved novel object recognition performance in transgenic mice, which showed clear recognition deficits. Complementing earlier studies, our results indicate that central inhibition of COMT positively impacts recognition memory processes and might constitute an appealing treatment for cognitive dysfunction related to neuropsychiatric disorders.

  7. Engineering catechol 1, 2-dioxygenase by design for improving the performance of the cis, cis-muconic acid synthetic pathway in Escherichia coli

    Science.gov (United States)

    Han, Li; Liu, Pi; Sun, Jixue; Wu, Yuanqing; Zhang, Yuanyuan; Chen, Wujiu; Lin, Jianping; Wang, Qinhong; Ma, Yanhe

    2015-01-01

    Regulating and ameliorating enzyme expression and activity greatly affects the performance of a given synthetic pathway. In this study, a new synthetic pathway for cis, cis-muconic acid (ccMA) production was reconstructed without exogenous induction by regulating the constitutive expression of the important enzyme catechol 1,2-dioxygenase (CatA). Next, new CatAs with significantly improved activities were developed to enhance ccMA production using structure-assisted protein design. Nine mutations were designed, simulated and constructed based on the analysis of the CatA crystal structure. These results showed that mutations at Gly72, Leu73 and/or Pro76 in CatA could improve enzyme activity, and the activity of the most effective mutant was 10-fold greater than that of the wild-type CatA from Acinetobacter sp. ADP1. The most productive synthetic pathway with a mutated CatA increased the titer of ccMA by more than 25%. Molecular dynamic simulation results showed that enlarging the entrance of the substrate-binding pocket in the mutants contributed to their increased enzyme activities and thus improved the performance of the synthetic pathway. PMID:26306712

  8. Effect of 3 Single-Dose Regimens of Opicapone on Levodopa Pharmacokinetics, Catechol-O-Methyltransferase Activity and Motor Response in Patients With Parkinson Disease.

    Science.gov (United States)

    Rocha, José-Francisco; Ferreira, Joaquim J; Falcão, Amílcar; Santos, Ana; Pinto, Roberto; Nunes, Teresa; Almeida, Luis; Soares-da-Silva, Patrício

    2016-05-01

    This study determined the effects of single doses of opicapone (OPC), a novel third-generation catechol-O-methyltransferase (COMT) inhibitor, on levodopa and 3-O-methyl-levodopa (3-OMD) pharmacokinetics (PK), COMT activity and motor fluctuations in patients with Parkinson disease (PD). Subjects received, in a double-blind manner, 25, 50, and 100 mg OPC or placebo (PLC) in 4 separate treatment periods. The washout period between doses was at least 10 days. During each period, the OPC/PLC capsules were to be coadministered with the morning dose of 100/25 mg levodopa/carbidopa (LC) or levodopa/benserazide (LB) on day 3. In relation to PLC, levodopa exposure increased 3.7%, 16.4%, and 34.8% following 25, 50, or 100 mg OPC, respectively. Maximum S-COMT inhibition (Emax ) ranged from 67.8% (25 mg OPC) to 100% (100 mg OPC). Peak and extent of S-COMT inhibition were dose-dependent. Maximum decrease in the plasma 3-OMD was observed following administration of 100 mg OPC. Opicapone administered concomitantly with standard-release 100/25 mg LC or LB improved motor performance. Treatments were generally well tolerated and safe. It was concluded that OPC is a new COMT inhibitor that significantly decreased COMT activity and increased systemic exposure to levodopa in PD patients with motor fluctuations.

  9. Investigating the genetic basis of theory of mind (ToM: the role of catechol-O-methyltransferase (COMT gene polymorphisms.

    Directory of Open Access Journals (Sweden)

    Haiwei Xia

    Full Text Available The ability to deduce other persons' mental states and emotions which has been termed 'theory of mind (ToM' is highly heritable. First molecular genetic studies focused on some dopamine-related genes, while the genetic basis underlying different components of ToM (affective ToM and cognitive ToM remain unknown. The current study tested 7 candidate polymorphisms (rs4680, rs4633, rs2020917, rs2239393, rs737865, rs174699 and rs59938883 on the catechol-O-methyltransferase (COMT gene. We investigated how these polymorphisms relate to different components of ToM. 101 adults participated in our study; all were genetically unrelated, non-clinical and healthy Chinese subjects. Different ToM tasks were applied to detect their theory of mind ability. The results showed that the COMT gene rs2020917 and rs737865 SNPs were associated with cognitive ToM performance, while the COMT gene rs5993883 SNP was related to affective ToM, in which a significant gender-genotype interaction was found (p = 0.039. Our results highlighted the contribution of DA-related COMT gene on ToM performance. Moreover, we found out that the different SNP at the same gene relates to the discriminative aspect of ToM. Our research provides some preliminary evidence to the genetic basis of theory of mind which still awaits further studies.

  10. Catechol-O-methyltransferase Val(108/158)Met polymorphism affects fronto-limbic connectivity during emotional processing in bipolar disorder.

    Science.gov (United States)

    Vai, B; Riberto, M; Poletti, S; Bollettini, I; Lorenzi, C; Colombo, C; Benedetti, F

    2016-12-30

    Catechol-O-methyltransferase (COMT) inactivates catecholamines, Val/Val genotype was associated to an increased amygdala (Amy) response to negative stimuli and can influence the symptoms severity and the outcome of bipolar disorder, probably mediated by the COMT polymorphism (rs4680) interaction between cortical and subcortical dopaminergic neurotransmission. The aim of this study is to explore how rs4680 and implicit emotional processing of negative emotional stimuli could interact in affecting the Amy connectivity in bipolar depression. Forty-five BD patients (34 Met carriers vs. 11 Val/Val) underwent fMRI scanning during implicit processing of fearful and angry faces. We explore the effect of rs4680 on the strength of functional connectivity from the amygdalae to whole brain. Val/Val and Met carriers significantly differed for the connectivity between Amy and dorsolateral prefrontal cortex (DLPFC) and supramarginal gyrus. Val/Val patients showed a significant positive connectivity for all of these areas, where Met carriers presented a significant negative one for the connection between DLPFC and Amy. Our findings reveal a COMT genotype-dependent difference in corticolimbic connectivity during affective regulation, possibly identifying a neurobiological underpinning of clinical and prognostic outcome of BD. Specifically, a worse antidepressant recovery and clinical outcome previously detected in Val/Val patients could be associated to a specific increased sensitivity to negative emotional stimuli.

  11. Determination of catechol-O-methyltransferase activity in brain tissue by high-performance liquid chromatography with on-line radiochemical detection

    Energy Technology Data Exchange (ETDEWEB)

    Nissinen, E.

    1985-01-01

    A sensitive assay for catechol-O-methyltransferase (COMT) activity by high-performance liquid chromatography with on-line radiochemical detection was described. The method was based on the measurement of /sup 3/H- labeled 3-O- and 4-O-methylated products of the substrate, 3,4- dihydroxybenzoic acid, using S-adenosyl-L-(methyl-/sup 3/H)methionine as the methyl donor, or the measurement of /sup 14/C-labeled 3-O- and 4-O-methylated products of the substrate, (7-/sup 14/C)dopamine. The reaction products were determined from the incubation mixture after removal of protein by injecting an aliquot into the liquid chromatograph. The detection limit with counting efficiency of 40% was 0.45 pmol /sup 3/H-labeled product, and 0. 04 pmol /sup 14/C-labeled product with 61% counting efficiency. The method is suitable for assaying membrane-bound and soluble COMT activities in the brain tissue and for calculation of meta/para product ratios.

  12. Association of codon 108/158 catechol-O-methyltransferase gene polymorphism with the psychiatric manifestations of velo-cardio-facial syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Lachman, H.M.; Papolos, D.F.; Veit, S. [Albert Einstein College of Medicine, Bronx, NY (United States)] [and others

    1996-09-20

    Velo-cardio-facial-syndrome (VCFS) is a common congenital disorder associated with typical facial appearance, cleft palate, cardiac defects, and learning disabilities. The majority of patients have an interstitial deletion on chromosome 22q11. In addition to physical abnormalities, a variety of psychiatric illnesses have been reported in patients with VCFS, including schizophrenia, bipolar disorder, and attention deficit hyperactivity disorder. The psychiatric manifestations of VCFS could be due to haploinsufficiency of a gene(s) within 22q11. One candidate that has been mapped to this region is catechol-O-methyltransferase (COMT). We recently identified a polymorphism in the COMT gene that leads to a valine{r_arrow}methionine substitution at amino acid 158 of the membrane-bound form of the enzyme. Homozygosity for COMT158{sup met} leads to a 3- to 4-fold reduction in enzymatic activity, compared with homozygotes for COMT158{sup met}. We now report that in a population of patients with VCFS, there is an apparent association between the low-activity allele, COMT158{sup met}, and the development of bipolar spectrum disorder, and in particular, a rapid-cycling form. 33 refs., 3 tabs.

  13. A novel Laccase Biosensor based on Laccase immobilized Graphene-Cellulose Microfiber Composite modified Screen-Printed Carbon Electrode for Sensitive Determination of Catechol.

    Science.gov (United States)

    Palanisamy, Selvakumar; Ramaraj, Sayee Kannan; Chen, Shen-Ming; Yang, Thomas C K; Yi-Fan, Pan; Chen, Tse-Wei; Velusamy, Vijayalakshmi; Selvam, Sonadevi

    2017-01-24

    In the present work, we demonstrate the fabrication of laccase biosensor to detect the catechol (CC) using laccase immobilized on graphene-cellulose microfibers (GR-CMF) composite modified screen printed carbon electrode (SPCE). The direct electrochemical behavior of laccase was investigated using laccase immobilized different modified SPCEs, such as GR/SPCE, CMF/SPCE and GR-CMF/SPCE. Compared with laccase immobilized GR and CMF modified SPCEs, a well-defined redox couple of Cu(I)/Cu(II) for laccase was observed at laccase immobilized GR-CMF composite modified SPCE. Cyclic voltammetry results show that the as-prepared biosensor has 7 folds higher catalytic activity with lower oxidation potential towards CC than SPCE modified with GR-CMF composite. Under optimized conditions, amperometric i-t method was used for the quantification of CC, and the amperometric response of the biosensor was linear over the concertation of CC ranging from 0.2 to 209.7 μM. The sensitivity, response time and the detection limit of the biosensor for CC is 0.932 μMμA(-1) cm(-2), 2 s and 0.085 μM, respectively. The biosensor has high selectivity towards CC in the presence of potentially active biomolecules and phenolic compounds. The biosensor also accessed for the detection of CC in different water samples and shows good practicality with an appropriate repea.

  14. Simultaneous Electrochemical Determination of Hydroquinone, Catechol and Resorcinol at Nitrogen Doped Porous Carbon Nanopolyhedrons-multiwall Carbon Nanotubes Hybrid Materials Modified Glassy Carbon Electrode

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wei; Wu, Liang; Zhang, Xiaohua; Chen, Jinhua [Hunan Univ., Changsha (China)

    2014-01-15

    The nitrogen doped porous carbon nanopolyhedrons (N-PCNPs)-multi-walled carbon nanotubes (MWCNTs) hybrid materials were prepared for the first time. Combining the excellent catalytic activities, good electrical conductivities and high surface areas of N-PCNPs and MWCNTs, the simultaneous determination of hydroquinone (HQ), catechol (CC) and resorcinol (RE) with good analytical performance was achieved at the N-PCNPs-MWCNTs modified electrode. The linear response ranges for HQ, CC and RE are 0.2-455 μM, 0.7-440 μM and 3.0-365 μM, respectively, and the detection limits (S/N = 3) are 0.03 μM, 0.11 μM and 0.38 μM, respectively. These results are much better than that obtained on some graphene or CNTs-based materials modified electrodes. Furthermore, the developed sensor was successfully applied to simultaneously detect HQ, CC and RE in the local river water samples.

  15. Electrochemical behavior of catechol, resorcinol and hydroquinone at graphene-chitosan composite film modified glassy carbon electrode and their simultaneous determination in water samples

    Energy Technology Data Exchange (ETDEWEB)

    Yin Huanshun [College of Chemistry and Material Science, Shandong Agricultural University, Taian, 271018 Shandong (China); College of Resources and Environment, Shandong Agricultural University, Taian 271018, Shandong (China); Zhang Qingming [College of Resources and Environment, Shandong Agricultural University, Taian 271018, Shandong (China); College of Chemistry and Pharmaceutical Sciences, Qingdao Agriculture University, Qingdao 266109 (China); Zhou Yunlei [College of Life Science, Beijing Normal University, 100875 Beijing (China); Ma Qiang; Liu Tao [College of Chemistry and Material Science, Shandong Agricultural University, Taian, 271018 Shandong (China); Zhu Lusheng, E-mail: lushzhu@sdau.edu.c [College of Resources and Environment, Shandong Agricultural University, Taian 271018, Shandong (China); Ai Shiyun, E-mail: ashy@sdau.edu.c [College of Chemistry and Material Science, Shandong Agricultural University, Taian, 271018 Shandong (China)

    2011-02-15

    Graphene-chitosan composite film modified glassy carbon electrode was prepared and characterized. The fabricated electrode showed excellent electrochemical catalytic activities towards the oxidation of catechol (CT), resorcinol (RS) and hydroquinone (HQ). The oxidation overpotentials of CT, RS and HQ decreased significantly and the corresponding oxidation currents increased remarkably compared with those obtained at the bare GCE and chitosan modified GCE. Some kinetic parameters, such as the electron transfer number (n), proton transfer number (m), charge transfer coefficient ({alpha}) and the apparent heterogeneous electron transfer rate constant (k{sub s}), were calculated. Differential pulse voltammetry was used for the simultaneous determination of CT, RS and HQ in their ternary mixture. The peak-to-peak potential separations between CT and RS, RS and HQ, and HQ and CT were 0.388, 0.484 and 0.096 V, respectively. The calibration curves for CT, RS and HQ were obtained in the range of 1 x 10{sup -6} to 4 x 10{sup -4}, 1 x 10{sup -6} to 5.5 x 10{sup -4} and 1 x 10{sup -6} to 3 x 10{sup -4} mol L{sup -1}, respectively. The detection limits were 7.5 x 10{sup -7} mol L{sup -1} (S/N = 3).

  16. 假单胞菌B5生物合成邻苯二酚的研究%Biosynthesis of catechol by Psuedomonas sp.B5

    Institute of Scientific and Technical Information of China (English)

    李江; 陈劲春; 吴卫华; 李军; 邹宝华

    2003-01-01

    以假单胞菌B5菌株(实验室筛选)为实验菌株,完成了游离细胞发酵条件优化和发酵保护剂甘油最适用量的研究.在6g/L的苯甲酸钠和1.1g/L培养基上30℃培养24h,邻苯二酚(catechol)产量达到2.5g/L,分子水平转化率为52.3%;同时进行细胞固定化材料、固定化条件和固定化发酵条件的实验.以1.5%壳聚糖和0.1%的海藻酸钙为固定化介质,0.1%的戊二醛交联制备得到的固定化细胞成球形,直径约为2.5mm,在苯甲酸钠(6g/L)培养基中可连续批次发酵12次,邻苯二酚平均产量约为每批次1.5g/L.

  17. The impact of the Catechol-O-methyltransferase Val158Met polymorphism on survival in the general population – the HUNT study

    Directory of Open Access Journals (Sweden)

    Skorpen Frank

    2007-06-01

    Full Text Available Abstract Background The catechol-O-methyltransferase (COMT gene contains a functional polymorphism, Val158Met which has been related to common diseases like cancer, psychiatric illness and myocardial infarction. Whether the Val158Met polymorphism is associated with survival has not been evaluated in the general population. The aim of this prospective study was to evaluate the impact of codon 158 COMT gene polymorphism on survival in a population-based cohort. Methods The sample comprised 2979 non-diabetic individuals who participated in the Nord-Trøndelag Health Study (HUNT in the period 1995–97. The subjects were followed up with respect to mortality throughout year 2004. Results 212 men and 183 women died during the follow up. No association between codon 158 COMT gene polymorphism and survival was found. The unadjusted relative risk of death by non-ischemic heart diseases with Met/Met or Met/Val genotypes was 3.27 (95% confidence interval, 1.19–9.00 compared to Val/Val genotype. When we adjusted for age, gender, smoking, coffee intake and body mass index the relative risk decreased to 2.89 (95% confidence interval, 1.04–8.00. Conclusion During 10 year of follow-up, the Val158Met polymorphism had no impact on survival in a general population. Difference in mortality rates from non-ischemic heart diseases may be incidental and should be evaluated in other studies.

  18. Association of catechol-O-methyltransferase Val(108/158) Met genetic polymorphism with schizophrenia, P50 sensory gating, and negative symptoms in a Chinese population.

    Science.gov (United States)

    Mao, Qiao; Tan, Yun-Long; Luo, Xing-Guang; Tian, Li; Wang, Zhi-Ren; Tan, Shu-Ping; Chen, Song; Yang, Gui-Gang; An, Hui-Mei; Yang, Fu-De; Zhang, Xiang-Yang

    2016-08-30

    Catechol-O-methyltransferase (COMT), an enzyme involved in the degradation and inactivation of the neurotransmitter dopamine, is associated with the sensory gating phenomenon, protecting the cerebral cortex from information overload. The COMT Val(108/158)Met polymorphism is essential for prefrontal cortex processing capacity and efficiency. The current study was designed to investigate the role of COMT Val(108/158)Met polymorphism in development, sensory gating deficit, and symptoms of schizophrenia in Han Chinese population. P50 gating was determined in 139 schizophrenic patients and 165 healthy controls. Positive and Negative Syndrome Scale (PANSS) was used to assess the clinical symptomatology in 370 schizophrenic subjects. COMT Val(108/158)Met polymorphism was genotyped by PCR-restriction fragment length polymorphism (PCR-RFLP). No significant differences in COMT allele and genotype distributions were observed between schizophrenic patients and control groups. Although P50 deficits were present in patients, there was no evidence for an association between COMT Val(108/158)Met polymorphism and the P50 biomarker. Moreover, PANSS negative subscore was significantly higher in Val allele carriers than in Met/Met individuals. The present findings suggest that COMT Val(108/158)Met polymorphism may not contribute to the risk of schizophrenia and to the P50 deficits, but may contribute to the negative symptoms of schizophrenia among Han Chinese.

  19. High quality draft genome sequence of Olivibacter sitiensis type strain (AW-6(T)), a diphenol degrader with genes involved in the catechol pathway.

    Science.gov (United States)

    Ntougias, Spyridon; Lapidus, Alla; Han, James; Mavromatis, Konstantinos; Pati, Amrita; Chen, Amy; Klenk, Hans-Peter; Woyke, Tanja; Fasseas, Constantinos; Kyrpides, Nikos C; Zervakis, Georgios I

    2014-06-15

    Olivibacter sitiensis Ntougias et al. 2007 is a member of the family Sphingobacteriaceae, phylum Bacteroidetes. Members of the genus Olivibacter are phylogenetically diverse and of significant interest. They occur in diverse habitats, such as rhizosphere and contaminated soils, viscous wastes, composts, biofilter clean-up facilities on contaminated sites and cave environments, and they are involved in the degradation of complex and toxic compounds. Here we describe the features of O. sitiensis AW-6(T), together with the permanent-draft genome sequence and annotation. The organism was sequenced under the Genomic Encyclopedia for Bacteria and Archaea (GEBA) project at the DOE Joint Genome Institute and is the first genome sequence of a species within the genus Olivibacter. The genome is 5,053,571 bp long and is comprised of 110 scaffolds with an average GC content of 44.61%. Of the 4,565 genes predicted, 4,501 were protein-coding genes and 64 were RNA genes. Most protein-coding genes (68.52%) were assigned to a putative function. The identification of 2-keto-4-pentenoate hydratase/2-oxohepta-3-ene-1,7-dioic acid hydratase-coding genes indicates involvement of this organism in the catechol catabolic pathway. In addition, genes encoding for β-1,4-xylanases and β-1,4-xylosidases reveal the xylanolytic action of O. sitiensis.

  20. Novel, unifying mechanism for mescaline in the central nervous system: electrochemistry, catechol redox metabolite, receptor, cell signaling and structure activity relationships.

    Science.gov (United States)

    Kovacic, Peter; Somanathan, Ratnasamy

    2009-01-01

    A unifying mechanism for abused drugs has been proposed previously from the standpoint of electron transfer. Mescaline can be accommodated within the theoretical framework based on redox cycling by the catechol metabolite with its quinone counterpart. Electron transfer may play a role in electrical effects involving the nervous system in the brain. This approach is in accord with structure activity relationships involving mescaline, abused drugs, catecholamines, and etoposide. Inefficient demethylation is in keeping with the various drug properties, such as requirement for high dosage and slow acting. There is a discussion of receptor binding, electrical effects, cell signaling and other modes of action. Mescaline is a nonselective, seretonin receptor agonist. 5-HTP receptors are involved in the stimulus properties. Research addresses the aspect of stereochemical requirements. Receptor binding may involve the proposed quinone metabolite and/or the amino sidechain via protonation. Electroencephalographic studies were performed on the effects of mescaline on men. Spikes are elicited by stimulation of a cortical area. The potentials likely originate in nonsynaptic dendritic membranes. Receptor-mediated signaling pathways were examined which affect mescaline behavior. The hallucinogen belongs to the class of 2AR agonists which regulate pathways in cortical neurons. The research identifies neural and signaling mechanisms responsible for the biological effects. Recently, another hallucinogen, psilocybin, has been included within the unifying mechanistic framework. This mushroom constituent is hydrolyzed to the phenol psilocin, also active, which is subsequently oxidized to an ET o-quinone or iminoquinone.

  1. Genetic Polymorphism of 1019C/G (rs6295) Promoter of Serotonin 1A Receptor and Catechol-O-Methyltransferase in Panic Disorder

    Science.gov (United States)

    Ishiguro, Shin; Aoki, Akiko; Ueda, Mikito; Hayashi, Yuki; Akiyama, Kazufumi; Kato, Kazuko; Shimoda, Kazutaka

    2017-01-01

    Objective Family and twin studies have suggested genetic liability for panic disorder (PD) and therefore we sought to determine the role of noradrenergic and serotonergic candidate genes for susceptibility for PD in a Japanese population. Methods In this age- and gender-matched case-control study involving 119 PD patients and 119 healthy controls, we examined the genotype distributions and allele frequencies of the serotonin transporter gene linked polymorphic region (5-HTTLPR), −1019C/G (rs6295) promoter polymorphism of the serotonin receptor 1A (5-HT1A), and catechol-O-methyltransferase (COMT) gene polymorphism (rs4680) and their association with PD. Results No significant differences were evident in the allele frequencies or genotype distributions of the COMT (rs4680), 5-HTTLPR polymorphisms or the −1019C/G (rs6295) promoter polymorphism of 5-HT1A between PD patients and controls. Although there were no significant associations of these polymorphisms with in subgroups of PD patients differentiated by gender or in subgroup comorbid with agoraphobia (AP), significant difference was observed in genotype distributions of the −1019C/G (rs6295) promoter polymorphism of 5-HT1A between PD patients without AP and controls (p=0.047). Conclusion In this association study, the 1019C/G (rs6295) promoter polymorphism of the 5-HT1A receptor G/G genotype was associated with PD without AP in a Japanese population. PMID:28096880

  2. Catechol-O-methyltransferase inhibition alters pain and anxiety-related volitional behaviors through activation of β-adrenergic receptors in the rat.

    Science.gov (United States)

    Kline, R H; Exposto, F G; O'Buckley, S C; Westlund, K N; Nackley, A G

    2015-04-02

    Reduced catechol-O-methyltransferase (COMT) activity resulting from genetic variation or pharmacological depletion results in enhanced pain perception in humans and nociceptive behaviors in animals. Using phasic mechanical and thermal reflex tests (e.g. von Frey, Hargreaves), recent studies show that acute COMT-dependent pain in rats is mediated by β-adrenergic receptors (βARs). In order to more closely mimic the characteristics of human chronic pain conditions associated with prolonged reductions in COMT, the present study sought to determine volitional pain-related and anxiety-like behavioral responses following sustained as well as acute COMT inhibition using an operant 10-45°C thermal place preference task and a light/dark preference test. In addition, we sought to evaluate the effects of sustained COMT inhibition on generalized body pain by measuring tactile sensory thresholds of the abdominal region. Results demonstrated that acute and sustained administration of the COMT inhibitor OR486 increased pain behavior in response to thermal heat. Further, sustained administration of OR486 increased anxiety behavior in response to bright light, as well as abdominal mechanosensation. Finally, all pain-related behaviors were blocked by the non-selective βAR antagonist propranolol. Collectively, these findings provide the first evidence that stimulation of βARs following acute or chronic COMT inhibition drives cognitive-affective behaviors associated with heightened pain that affects multiple body sites.

  3. Effect of surfactant-induced cell surface modifications on electron transport system and catechol 1,2-dioxygenase activities and phenanthrene biodegradation by Citrobacter sp. SA01.

    Science.gov (United States)

    Li, Feng; Zhu, Lizhong

    2012-11-01

    In order to better understand how surfactants affect biodegradation of hydrophobic organic compounds (HOCs), Tween 80 and sodium dodecyl benzene sulfonate (SDBS), were selected to investigate effects on cell surface hydrophobicity (CSH), electron transport system (ETS) activities and phenanthrene biodegradation by Citrobacter sp. SA01. Tween 80 and SDBS increased CSH by 19.8-25.2%, ETS activities by 352.1-376.0μmol/gmin, catechol 1,2-dioxygenase (C12) activities by 50.8-52.7U/L, and phenanthrene biodegradation by 8.9-17.2% separately in the presence of 50mg/L of surfactants as compared to in their absence. Lipopolysaccharide (LPS) release was 334.7μg/mg in the presence of both surfactants whereas in their absence only 8.6-44.4μg/mg of LPS was released. Thus, enhanced LPS release probably increased ETS and C12 activities as well as phenanthrene biodegradation by increasing CSH. The results demonstrate that surfactant-enhanced CSH provides a simple, yet effective strategy for field applications of surfactant-enhanced bioremediation of HOCs.

  4. A novel Laccase Biosensor based on Laccase immobilized Graphene-Cellulose Microfiber Composite modified Screen-Printed Carbon Electrode for Sensitive Determination of Catechol

    Science.gov (United States)

    Palanisamy, Selvakumar; Ramaraj, Sayee Kannan; Chen, Shen-Ming; Yang, Thomas C. K.; Yi-Fan, Pan; Chen, Tse-Wei; Velusamy, Vijayalakshmi; Selvam, Sonadevi

    2017-01-01

    In the present work, we demonstrate the fabrication of laccase biosensor to detect the catechol (CC) using laccase immobilized on graphene-cellulose microfibers (GR-CMF) composite modified screen printed carbon electrode (SPCE). The direct electrochemical behavior of laccase was investigated using laccase immobilized different modified SPCEs, such as GR/SPCE, CMF/SPCE and GR-CMF/SPCE. Compared with laccase immobilized GR and CMF modified SPCEs, a well-defined redox couple of CuI/CuII for laccase was observed at laccase immobilized GR-CMF composite modified SPCE. Cyclic voltammetry results show that the as-prepared biosensor has 7 folds higher catalytic activity with lower oxidation potential towards CC than SPCE modified with GR-CMF composite. Under optimized conditions, amperometric i-t method was used for the quantification of CC, and the amperometric response of the biosensor was linear over the concertation of CC ranging from 0.2 to 209.7 μM. The sensitivity, response time and the detection limit of the biosensor for CC is 0.932 μMμA‑1 cm‑2, 2 s and 0.085 μM, respectively. The biosensor has high selectivity towards CC in the presence of potentially active biomolecules and phenolic compounds. The biosensor also accessed for the detection of CC in different water samples and shows good practicality with an appropriate repea.

  5. The Cu-MOF-199/single-walled carbon nanotubes modified electrode for simultaneous determination of hydroquinone and catechol with extended linear ranges and lower detection limits.

    Science.gov (United States)

    Zhou, Jian; Li, Xi; Yang, Linlin; Yan, Songlin; Wang, Mengmeng; Cheng, Dan; Chen, Qi; Dong, Yulin; Liu, Peng; Cai, Weiquan; Zhang, Chaocan

    2015-10-29

    A novel electrochemical sensor based on Cu-MOF-199 [Cu-MOF-199 = Cu3(BTC)2 (BTC = 1,3,5-benzenetricarboxylicacid)] and SWCNTs (single-walled carbon nanotubes) was fabricated for the simultaneous determination of hydroquinone (HQ) and catechol (CT). The modification procedure was carried out through casting SWCNTs on the bare glassy carbon electrode (GCE) and followed by the electrodeposition of Cu-MOF-199 on the SWCNTs modified electrode. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) were performed to characterize the electrochemical performance and surface characteristics of the as-prepared sensor. The composite electrode exhibited an excellent electrocatalytic activity with increased electrochemical signals towards the oxidation of HQ and CT, owing to the synergistic effect of SWCNTs and Cu-MOF-199. Under the optimized condition, the linear response range were from 0.1 to 1453 μmol L(-1) (RHQ = 0.9999) for HQ and 0.1-1150 μmol L(-1) (RCT = 0.9990) for CT. The detection limits for HQ and CT were as low as 0.08 and 0.1 μmol L(-1), respectively. Moreover, the modified electrode presented the good reproducibility and the excellent anti-interference performance. The analytical performance of the developed sensor for the simultaneous detection of HQ and CT had been evaluated in practical samples with satisfying results.

  6. The activity of ascorbic acid and catechol oxidase, the rate of photosynthesis and respiration as related to plant organs, stage of development and copper supply

    Directory of Open Access Journals (Sweden)

    St. Łyszcz

    2015-06-01

    Full Text Available Some experiments were performed to investigate the physiological role of copper in oat and sunflower and to recognize some effects of copper deficiency. Oat and sunflower plants were grown in pots on a peat soil under copper deficiency conditions (–Cu or with the optimal copper supply (+Cu. In plants the following measurements were carried out: 1 the activity of ascorbic acid oxidase (AAO and of catechol oxidase (PPO in different plant organs and at different stages of plant development, 2 the activity and the rate of photosynthesis, 3 the activity of RuDP-carboxylase, 4 the intensity of plant respiration. The activity of AAO and of PPO, and also the rate and the activity of photosynthesis were significantly lower under conditions of copper deficiency. The activity of both discussed oxidases depended on: 1 the plant species, 2 plant organs, 3 stage of plant development. Copper deficiency caused decrease of the respiration intensity of sunflower leaves but it increased to some extent the respiration of oat tops. Obtained results are consistent with the earlier suggestion of the authors that the PPO activity in sunflower leaves could be a sensitive indicator of copper supply of the plants, farther experiments are in progress.

  7. The Separation of Catechol from Carbofuran Phenol by Extractive Distillation%萃取精馏分离呋喃酚中邻苯二酚

    Institute of Scientific and Technical Information of China (English)

    张建宇; 胡艾希; 王宇; 肖旭辉; 郭家斌; 罗先福

    2009-01-01

    In this study, extractive distillation has been applied to separate catechol (CAT) from carbofuran phenol (CFP) with high purity and yield. The relative volatility of CFP to CAT was measured, and the choice of separating agents was investigated. The experimental results indicated that CFP/CAT is an azeotropic system with an azeotropic point at 93.40℃/0.400 kPa and an azeotropic mixture containing 49.96% of CFP and 50.04% of CAT. Data from the determination of the relative volatility have shown that separating agents such as diglycol and 4-butylcatechol (4-TBC) are able to increase the relative volatility up to 1.90. In one shot process batch extractive distillation of CFP mixture with 3% (by mass) diglycol as separating agent, the purity and yield of the obtained CFP was 99.0% and 95.0%, respectively, while the distillation without separating agent provided a purity and yield of only 98.0% and 90.0%, respectively. There was no residual separating agent found in the product.

  8. A pH-responsive drug nanovehicle constructed by reversible attachment of cholesterol to PEGylated poly(l-lysine) via catechol-boronic acid ester formation.

    Science.gov (United States)

    Yang, Bin; Lv, Yin; Zhu, Jing-Yi; Han, Yun-Tao; Jia, Hui-Zhen; Chen, Wei-Hai; Feng, Jun; Zhang, Xian-Zheng; Zhuo, Ren-Xi

    2014-08-01

    The present work reports the construction of a drug delivery nanovehicle via a pH-sensitive assembly strategy for improved cellular internalization and intracellular drug liberation. Through spontaneous formation of boronate linkage in physiological conditions, phenylboronic acid-modified cholesterol was able to attach onto catechol-pending methoxypoly(ethylene glycol)-block-poly(l-lysine). This comb-type polymer can self-organize into a micellar nanoconstruction that is able to effectively encapsulate poorly water-soluble agents. The blank micelles exhibited negligible in vitro cytotoxicity, yet doxorubicin (DOX)-loaded micelles could effectively induce cell death at a level comparable to free DOX. Owing to the acid-labile feature of the boronate linkage, a reduction in environmental pH from pH 7.4 to 5.0 could trigger the dissociation of the nanoconstruction, which in turn could accelerate the liberation of entrapped drugs. Importantly, the blockage of endosomal acidification in HeLa cells by NH4Cl treatment significantly decreased the nuclear uptake efficiency and cell-killing effect mediated by the DOX-loaded nanoassembly, suggesting that acid-triggered destruction of the nanoconstruction is of significant importance in enhanced drug efficacy. Moreover, confocal fluorescence microscopy and flow cytometry assay revealed the effective internalization of the nanoassemblies, and their cellular uptake exhibited a cholesterol dose-dependent profile, indicating the contribution of introduced cholesterol functionality to the transmembrane process of the nanoassembly.

  9. The Simultaneous Electrochemical Detection of Catechol and Hydroquinone with [Cu(Sal-β-Ala(3,5-DMPz2]/SWCNTs/GCE

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    Lina Abdullah Alshahrani

    2014-11-01

    Full Text Available A glassy carbon electrode was modified with a copper(II complex [Cu(Sal-β-Ala (3,5-DMPz2] (Sal = salicylaldehyde, β-Ala = β-alanine, 3,5-DMPz = 3,5-dimethylpyrazole and single-walled carbon nanotubes (SWCNTs. The modified electrode was used to detect catechol (CT and hydroquinone (HQ and exhibited good electrocatalytic activities toward the oxidation of CT and HQ. The peak currents were linear with the CT and HQ concentrations over the range of 5–215 μmol·L−1 and 5–370 μmol·L−1 with corresponding detection limits of 3.5 μmol·L−1 and 1.46 μmol·L−1 (S/N = 3 respectively. Moreover, the modified electrode exhibited good sensitivity, stability and reproducibility for the determination of CT and HQ, indicating the promising applications of the modified electrode in real sample analysis.

  10. Catechol inhibits FADH2-linked respiration in rat liver mitochondrial fraction Catecol inibe FADH2 ligado à respiração na fração mitochondrial do fígado do rato

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    George Emílio Sampaio Barreto

    2005-01-01

    Full Text Available PURPOSE: The aim of this work was to investigate the hypothesis that catechol inhibits FADH2-linked basal respiration in mitochondria isolated from rat liver homogenates. Moreover, catechol ability to induce peroxidation of biomolecules in liver nuclear fractions was also studied. METHODS: Rat liver homogenates were incubated with 1mM 1,2-dihydroxybenzene (catechol at pH 7.4 for up to 30 minutes. After that, mitochondrial fractions were isolated by differential centrifugation. Basal oxygen uptake was measured using a Clark-type electrode after the addition of 10 mM sodium succinate. Nuclear fractions were incubated in the presence of 1 mM catechol for 17 hours at room temperature and the peroxidation of biomolecules was investigated by the reaction with thiobarbituric acid, which was determined spectrophotometrically at 535 nm. RESULTS: Catechol induced a time-dependent partial inhibition of FADH2-linked basal mitochondrial respiration, however this substance was unable to induce a direct peroxidation of biomolecules in hepatic nuclear fractions. CONCLUSION: Catechol produced an inhibition of basal respiration associated to FADH2 in isolated liver mitochondria that could lead to cytotoxicity, ROS generation and cell death.OBJETIVO: Testar a hipótese do catecol inibir a respiração basal associada ao FADH2 em frações mitocondriais hepáticas de rato. Além disso, estudou-se também a capacidade do catecol de induzir peroxidação de biomoléculas nas frações nucleares. MÉTODOS: Os homogeneizados de fígado de ratos foram incubados com catecol a 1 mM em pH fisiológico. Depois disso, as frações mitocondriais foram isoladas por centrifugação diferencial. O consumo basal de oxigênio foi medido com um eletrodo do tipo Clark após injeção de succinato a 10 mM. Frações nucleares foram incubadas com catecol por 17 horas à temperatura ambiente e a peroxidação de biomoléculas foi investigada pela reação com o ácido tiobarbitúrico e

  11. Study on the application of reduced graphene oxide and multiwall carbon nanotubes hybrid materials for simultaneous determination of catechol, hydroquinone, p-cresol and nitrite

    Energy Technology Data Exchange (ETDEWEB)

    Hu Fangxin [Education Ministry Key Laboratory on Luminescence and Real-Time Analysis, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Chen Shihong, E-mail: cshong@swu.edu.cn [Education Ministry Key Laboratory on Luminescence and Real-Time Analysis, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Wang Chengyan [Education Ministry Key Laboratory on Luminescence and Real-Time Analysis, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Yuan Ruo, E-mail: yuanruo@swu.edu.cn [Education Ministry Key Laboratory on Luminescence and Real-Time Analysis, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Yuan Dehua; Wang Cun [Education Ministry Key Laboratory on Luminescence and Real-Time Analysis, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China)

    2012-04-29

    Graphical abstract: In this paper, the reduced graphene oxide and multiwall carbon nanotubes hybrid materials (RGO-MWNTs) were prepared and a novel strategy for the simultaneous determination of multiple environmental contaminations has been proposed on the basis of RGO-MWNTs hybrid materials modified electrode. The hybrid materials were characterized by the scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and N{sub 2} sorption-desorption isotherms. Due to the excellent catalytic activity, enhanced electrical conductivity, high surface area and porous structure of the RGO-MWNTs, the RGO-MWNTs/GCE achieved the simultaneous measurement of hydroquinone (HQ), catechol (CC), p-cresol (PC) and nitrite (NO{sub 2}{sup -}) with well-separate four peaks. Scheme 1a illuminated the preparation process of the RGO-MWNTs hybrid materials. Scheme 1b explains the electron mediating properties of RGO-MWNTs/GCE towards the oxidation of HQ, CC, PC and NO{sub 2}{sup -}. Scheme 1c presented the SEM image of RGO-MWNTs hybrid materials. Scheme 1d and e showed the 2D and 3D AFM images of RGO-MWNTs films, respectively. Highlights: Black-Right-Pointing-Pointer The novel RGO-MWNTs hybrid materials were synthesized. Black-Right-Pointing-Pointer The simultaneous detection of four environmental contaminations was achieved. Black-Right-Pointing-Pointer SEM, AFM, XPS was employed to characterize the RGO-MWNTs hybrid materials. - Abstract: In this paper, the reduced graphene oxide and multiwall carbon nanotubes hybrid materials (RGO-MWNTs) were prepared and a strategy for detecting environmental contaminations was proposed on the basis of RGO-MWNTs modified electrode. The hybrid materials were characterized by the scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and N{sub 2} sorption-desorption isotherms. Due to the excellent catalytic activity, enhanced electrical conductivity and high

  12. A new approach on the purification of recombinant human soluble catechol-O-methyltransferase from an Escherichia coli extract using hydrophobic interaction chromatography.

    Science.gov (United States)

    Passarinha, L A; Bonifácio, M J; Soares-da-Silva, P; Queiroz, J A

    2008-01-11

    Catechol-O-methyltransferase (COMT) is a significant target in protein engineering due to its role not only in normal brain function but also to its possible involvement in some human disorders. In this work, a new approach was employed for the purification of recombinant human soluble COMT (hSCOMT) using hydrophobic interaction chromatography, as the main isolation method, from an Escherichia coli culture broth. A simplified overall process flow is proposed. Indeed, with an optimized heterologous expression system for recombinant hSCOMT production, such as E. coli, it was possible to produce and recover the active monomeric enzyme directly from the cell crude culture broth either by a freeze/thaw or ultrasonication lysis step. The recombinant enzyme present in the bacterial soluble fraction, exhibited similar affinity for epinephrine (K(m) 276 [215; 337] microM) and the methyl donor (S-adenosyl-L-methionine, SAMe) (K(m) 36 [30; 41]microM) as human SCOMT. After the precipitation step by 55% of ammonium sulphate, a HIC step on the butyl-sepharose resin was found to be highly effective in selectively eluting a range of contaminating key proteins present in the concentrate soluble extract. Consequently, the partially purified eluate from HIC could then be loaded and polished by gel filtration in order to increase the process efficiency. The final product appeared as a single band in sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The procedure resulted in a global 10.9-fold purification with a specific activity of 5500 nmol/h/mg of protein. The widespread applicability of the process, here described, to different COMT sources could make this protocol highly useful for all studies requiring purified and active COMT proteins.

  13. Epistatic and functional interactions of catechol-o-methyltransferase (COMT and AKT1 on neuregulin1-ErbB signaling in cell models.

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    Yoshitatsu Sei

    Full Text Available BACKGROUND: Neuregulin1 (NRG1-ErbB signaling has been implicated in the pathogenesis of cancer and schizophrenia. We have previously reported that NRG1-stimulated migration of B lymphoblasts is PI3K-AKT1dependent and impaired in patients with schizophrenia and significantly linked to the catechol-o-methyltransferase (COMT Val108/158Met functional polymorphism. METHODOLOGY/PRINCIPAL FINDINGS: We have now examined AKT1 activation in NRG1-stimulated B lymphoblasts and other cell models and explored a functional relationship between COMT and AKT1. NRG1-induced AKT1 phosphorylation was significantly diminished in Val carriers compared to Met carriers in both normal subjects and in patients. Further, there was a significant epistatic interaction between a putatively functional coding SNP in AKT1 (rs1130233 and COMT Val108/158Met genotype on AKT1 phosphorylation. NRG1 induced translocation of AKT1 to the plasma membrane also was impaired in Val carriers, while PIP(3 levels were not decreased. Interestingly, the level of COMT enzyme activity was inversely correlated with the cells' ability to synthesize phosphatidylserine (PS, a factor that attracts the pleckstrin homology domain (PHD of AKT1 to the cell membrane. Transfection of SH-SY5Y cells with a COMT Val construct increased COMT activity and significantly decreased PS levels as well as NRG1-induced AKT1 phosphorylation and migration. Administration of S-adenosylmethionine (SAM rescued all of these deficits. These data suggest that AKT1 function is influenced by COMT enzyme activity through competition with PS synthesis for SAM, which in turn dictates AKT1-dependent cellular responses to NRG1-mediated signaling. CONCLUSION/SIGNIFICANCE: Our findings implicate genetic and functional interactions between COMT and AKT1 and may provide novel insights into pathogenesis of schizophrenia and other ErbB-associated human diseases such as cancer.

  14. Differential Genetic and Epigenetic Regulation of Catechol-O-Methyl-Transferase (COMT is Associated with Impaired Fear Inhibition in Posttraumatic Stress Disorder

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    Seth Davin Norrholm

    2013-04-01

    Full Text Available The catechol-O-methyltransferase (COMT enzyme is critical for the catabolic regulation of synaptic dopamine, resulting in altered cortical functioning. The COMT Val158Met polymorphism has been implicated in human mental illness, with Met/Met homozygotes associated with increased susceptibility to posttraumatic stress disorder (PTSD. Our primary objective was to examine the intermediate phenotype of fear inhibition in PTSD stratified by COMT genotype (Met/Met, Val/Met, and Val/Val and differential gene regulation via methylation status at CpG sites in the COMT promoter region. More specifically, we examined the potential interaction of COMT genotype and PTSD diagnosis on fear-potentiated startle during fear conditioning and extinction and COMT DNA methylation levels (as determined using genomic DNA isolated from whole blood . Participants were recruited from medical and gynecological clinics of an urban hospital in Atlanta, Georgia. We found that individuals with the Met/Met genotype demonstrated higher fear-potentiated startle to the CS- (safety signal and during extinction of the CS+ (danger signal compared to Val/Met and Val/Val genotypes. The PTSD+ Met/Met genotype group had the greatest impairment in fear inhibition to the CS- (p=.006, compared to Val carriers. In addition, the Met/Met genotype was associated with DNA methylation at 4 CpG sites, 2 of which were associated with impaired fear inhibition to the safety signal. These results suggest that multiple differential mechanisms for regulating COMT function – at the level of protein structure via the Val158Met genotype and at the level of gene regulation via differential methylation - are associated with impaired fear inhibition in PTSD.

  15. Catechol-Functionalized Hyaluronic Acid Hydrogels Enhance Angiogenesis and Osteogenesis of Human Adipose-Derived Stem Cells in Critical Tissue Defects.

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    Park, Hyun-Ji; Jin, Yoonhee; Shin, Jisoo; Yang, Kisuk; Lee, Changhyun; Yang, Hee Seok; Cho, Seung-Woo

    2016-06-13

    Over the last few decades, stem cell therapies have been highlighted for their potential to heal damaged tissue and aid in tissue reconstruction. However, materials used to deliver and support implanted cells often display limited efficacy, which has resulted in delaying translation of stem cell therapies into the clinic. In our previous work, we developed a mussel-inspired, catechol-functionalized hyaluronic acid (HA-CA) hydrogel that enabled effective cell transplantation due to its improved biocompatibility and strong tissue adhesiveness. The present study was performed to further expand the utility of HA-CA hydrogels for use in stem cell therapies to treat more clinically relevant tissue defect models. Specifically, we utilized HA-CA hydrogels to potentiate stem cell-mediated angiogenesis and osteogenesis in two tissue defect models: critical limb ischemia and critical-sized calvarial bone defect. HA-CA hydrogels were found to be less cytotoxic to human adipose-derived stem cells (hADSCs) in vitro compared to conventional photopolymerized HA hydrogels. HA-CA hydrogels also retained the angiogenic functionality of hADSCs and supported osteogenic differentiation of hADSCs. Because of their superior tissue adhesiveness, HA-CA hydrogels were able to mediate efficient engraftment of hADSCs into the defect regions. When compared to photopolymerized HA hydrogels, HA-CA hydrogels significantly enhanced hADSC-mediated therapeutic angiogenesis (promoted capillary/arteriole formation, improved vascular perfusion, attenuated ischemic muscle degeneration/fibrosis, and reduced limb amputation) and bone reconstruction (mineralized bone formation, enhanced osteogenic marker expression, and collagen deposition). This study proves the feasibility of using bioinspired HA-CA hydrogels as functional biomaterials for improved tissue regeneration in critical tissue defects.

  16. 邻苯二酚亚甲基化合成胡椒环%Synthesis of 1,3-Benzodioxole by Catechol Methylenation

    Institute of Scientific and Technical Information of China (English)

    杨涛; 赵匡民; 张玲; 方培华; 蒋文伟

    2012-01-01

    [Aims] A new synthesis techniques of 1,3-benzodioxole was reported. [Methods] 1,3-Benzodioxole was synthesized by using catechol, dichloromethane as the starting materials and DMSO as solvent under the condition of alkali (K2CO2) and normal pressure. In order to get the optimum reaction condition, the effects of material confect, temperature, reaction time, solvent and dosage of alkali were studied. [Results] The yield of product is 89.1%. Results showed that the product is 1,3-benzodioxole by analysis of IR, lH NMR and GC with the purity of 98%. [Conclusions] New technology is a kind of method suitable for industrial production.%[目的]报道胡椒环合成的新工艺.[方法]以邻苯二酚和二氯甲烷为原料,DMSO作为溶剂,在碱性(K2CO3)环境下合成胡椒环,并通过研究溶剂、温度、反应时间、反应物配比和碱用量对产品收率的影响得到最优工艺条件.[结果]产品收率达89.1%.利用红外光谱、核磁共振和气相色谱分析得产品是胡椒环,纯度达98%.[结论]新工艺是一种适合工业生产的方法.

  17. Surface functionalization of titanium implants with chitosan-catechol conjugate for suppression of ROS-induced cells damage and improvement of osteogenesis.

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    Chen, Weizhen; Shen, Xinkun; Hu, Yan; Xu, Kui; Ran, Qichun; Yu, Yonglin; Dai, Liangliang; Yuan, Zhang; Huang, Ling; Shen, Tingting; Cai, Kaiyong

    2017-01-01

    Oxidative stress induced by reactive oxygen species (ROS) overproduction would hinder bone healing process at the interface of bone/implant, yet underlying mechanism remains to be explored. To endow titanium (Ti) substrates with antioxidant activity for enhanced bone formation, multilayered structure composing of chitosan-catechol (Chi-C), gelatin (Gel) and hydroxyapatite (HA) nanofibers was constructed on Ti substrates. Surface wettability and topography of multilayer coated Ti substrates were characterized by water contact angle measurement, scanning electron microscopy and atomic force microscopy, respectively. Chi-C containing multilayer on Ti surface effectively protected osteoblasts from ROS damage, which was revealed by high level of intracellular ROS scavenging activity and reduced oxidative damage on cellular level by regulating the expression of cell adhesion related genes (integrin αv, β3, CDH11 and CDH2). Moreover, it regulated the production of cell adhesive and anti-apoptotic related proteins (p-MYPT1, p-FAK, p-Akt and Bcl-2) and pro-apoptotic critical executioners (Bax and cleaved caspase 3). Beside, the composite multilayer of Chi-C/Gel/HA nanofibers on Ti substrates promoted osteoblasts differentiation, which was evidenced by high expression levels of alkaline phosphatase activity, collagen secretion, ECM mineralization and osteogenesis-related genes expression in vitro. The in vivo experiments of μ-CT analysis, push out test and histochemistry staining further confirmed that Chi-C multilayered implant had great potential for improved early bone healing. Overall, the study offers an effective strategy for the exploration of high quality Ti implants for orthopedic applications.

  18. The val158met polymorphism of human catechol-O-methyltransferase (COMT affects anterior cingulate cortex activation in response to painful laser stimulation

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    Musso Francesco

    2010-05-01

    Full Text Available Abstract Background Pain is a complex experience with sensory, emotional and cognitive aspects. Genetic and environmental factors contribute to pain-related phenotypes such as chronic pain states. Genetic variations in the gene coding for catechol-O-methyltransferase (COMT have been suggested to affect clinical and experimental pain-related phenotypes including regional μ-opioid system responses to painful stimulation as measured by ligand-PET (positron emission tomography. The functional val158met single nucleotide polymorphism has been most widely studied. However, apart from its impact on pain-induced opioid release the effect of this genetic variation on cerebral pain processing has not been studied with activation measures such as functional magnetic resonance imaging (fMRI, PET or electroencephalography. In the present fMRI study we therefore sought to investigate the impact of the COMT val158met polymorphism on the blood oxygen level-dependent (BOLD response to painful laser stimulation. Results 57 subjects were studied. We found that subjects homozygous for the met158 allele exhibit a higher BOLD response in the anterior cingulate cortex (ACC, foremost in the mid-cingulate cortex, than carriers of the val158 allele. Conclusion This result is in line with previous studies that reported higher pain sensitivity in homozygous met carriers. It adds to the current literature in suggesting that this behavioral phenotype may be mediated by, or is at least associated with, increased ACC activity. More generally, apart from one report that focused on pain-induced opioid release, this is the first functional neuroimaging study showing an effect of the COMT val158met polymorphism on cerebral pain processing.

  19. Depression and anxiety in relation to catechol-O-methyltransferase Val158Met genotype in the general population: The Nord-Trøndelag Health Study (HUNT

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    Zwart John-Anker

    2008-06-01

    Full Text Available Abstract Background The catechol-O-methyltransferase (COMT gene contains a functional polymorphism, Val158Met, which has been linked to anxiety and depression, but previous results are not conclusive. The aim of the present study was to examine the relationship between the Val158Met COMT gene polymorphism and anxiety and depression measured by the Hospital Anxiety and Depression Scale (HADS in the general adult population. Methods In the Nord-Trøndelag Health Study (HUNT the association between the Val158Met polymorphism and anxiety and depression was evaluated in a random sample of 5531 individuals. Two different cut off scores (≥ 8 and ≥ 11 were used to identify cases with anxiety (HADS-A and depression (HADS-D, whereas controls had HADS-A Results The COMT genotype distribution was similar between controls and individuals in the groups with anxiety and depression using cut-off scores of ≥ 8. When utilizing the alternative cut-off score HADS-D ≥ 11, Met/Met genotype and Met allele were less common among men with depression compared to the controls (genotype: p = 0.017, allele: p = 0.006. In the multivariate analysis, adjusting for age and heart disease, depression (HADS-D ≥ 11 was less likely among men with the Met/Met genotype than among men with the Val/Val genotype (OR = 0.37, 95% CI = 0.18–0.76. Conclusion In this population-based study, no clear association between the Val158Met polymorphism and depression and anxiety was revealed. The Met/Met genotype was less likely among men with depression defined as HADS-D ≥ 11, but this may be an incidental finding.

  20. Associations of Cigarette Smoking and Polymorphisms in Brain-Derived Neurotrophic Factor and Catechol-O-Methyltransferase with Neurocognition in Alcohol Dependent Individuals during Early Abstinence

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    Timothy eDurazzo

    2012-10-01

    Full Text Available Chronic cigarette smoking and polymorphisms in brain-derived neurotrophic factor (BDNF and catechol-o-methyltransferase (COMT are associated with neurocognition in normal controls and those with various neuropsychiatric conditions. The influence of these polymorphisms on neurocognition in alcohol dependence is unclear. The goal of this report was to investigate the associations of single nucleotide polymorphisms (SNP in BDNF Val66Met and COMT Val158Met with neurocognition in a treatment-seeking alcohol dependent cohort and determine if neurocognitive differences between non-smokers and smokers previously observed in this cohort persist when controlled for these functional SNPs. Genotyping was conducted on 70 primarily male treatment-seeking alcohol dependent participants (ALC who completed a comprehensive neuropsychological battery after 33 ± 9 days of monitored abstinence. Smoking ALC performed significantly worse than non-smoking ALC on the domains of auditory-verbal and visuospatial learning and memory, cognitive efficiency, general intelligence, processing speed and global neurocognition. In smoking ALC, greater number of years of smoking over lifetime was related to poorer performance on multiple domains. COMT Met homozygotes were superior to Val homozygotes on measures of executive skills and showed trends for higher general intelligence and visuospatial skills, while COMT Val/Met heterozygotes showed significantly better general intelligence than Val homozygotes. COMT Val homozygotes performed better than heterozygotes on auditory-verbal memory. BDNF genotype was not related to any neurocognitive domain. The findings are consistent with studies in normal controls and neuropsychiatric cohorts that observed COMT Met carriers showed better performance on measures of executive skills and general intelligence. Overall, the findings support to the expanding clinical movement to make smoking cessation programs available at the inception of

  1. Phase II metabolism in human skin: skin explants show full coverage for glucuronidation, sulfation, N-acetylation, catechol methylation, and glutathione conjugation.

    Science.gov (United States)

    Manevski, Nenad; Swart, Piet; Balavenkatraman, Kamal Kumar; Bertschi, Barbara; Camenisch, Gian; Kretz, Olivier; Schiller, Hilmar; Walles, Markus; Ling, Barbara; Wettstein, Reto; Schaefer, Dirk J; Itin, Peter; Ashton-Chess, Joanna; Pognan, Francois; Wolf, Armin; Litherland, Karine

    2015-01-01

    Although skin is the largest organ of the human body, cutaneous drug metabolism is often overlooked, and existing experimental models are insufficiently validated. This proof-of-concept study investigated phase II biotransformation of 11 test substrates in fresh full-thickness human skin explants, a model containing all skin cell types. Results show that skin explants have significant capacity for glucuronidation, sulfation, N-acetylation, catechol methylation, and glutathione conjugation. Novel skin metabolites were identified, including acyl glucuronides of indomethacin and diclofenac, glucuronides of 17β-estradiol, N-acetylprocainamide, and methoxy derivatives of 4-nitrocatechol and 2,3-dihydroxynaphthalene. Measured activities for 10 μM substrate incubations spanned a 1000-fold: from the highest 4.758 pmol·mg skin(-1)·h(-1) for p-toluidine N-acetylation to the lowest 0.006 pmol·mg skin(-1)·h(-1) for 17β-estradiol 17-glucuronidation. Interindividual variability was 1.4- to 13.0-fold, the highest being 4-methylumbelliferone and diclofenac glucuronidation. Reaction rates were generally linear up to 4 hours, although 24-hour incubations enabled detection of metabolites in trace amounts. All reactions were unaffected by the inclusion of cosubstrates, and freezing of the fresh skin led to loss of glucuronidation activity. The predicted whole-skin intrinsic metabolic clearances were significantly lower compared with corresponding whole-liver intrinsic clearances, suggesting a relatively limited contribution of the skin to the body's total systemic phase II enzyme-mediated metabolic clearance. Nevertheless, the fresh full-thickness skin explants represent a suitable model to study cutaneous phase II metabolism not only in drug elimination but also in toxicity, as formation of acyl glucuronides and sulfate conjugates could play a role in skin adverse reactions.

  2. Catechol-O-methyltransferase gene variants may associate with negative symptom response and plasma concentrations of prolactin in schizophrenia after amisulpride treatment.

    Science.gov (United States)

    Chen, Chun-Yen; Yeh, Yi-Wei; Kuo, Shin-Chang; Ho, Pei-Shen; Liang, Chih-Sung; Yen, Che-Hung; Lu, Ru-Band; Huang, San-Yuan

    2016-03-01

    Catechol-O-methyltransferase (COMT) enzyme is involved in the pathogenesis of psychotic symptoms and may be associated with a therapeutic response to antipsychotic drugs. The aim of this study was to examine the relationship between COMT variants, plasma prolactin level, and the therapeutic effectiveness of amisulpride treatment in patients with schizophrenia. A 12-week naturalistic study of amisulpride treatment was carried out in 185 Han Chinese patients with schizophrenia. The patients were screened for 14 single-nucleotide polymorphisms of the COMT gene. The Positive and Negative Syndrome Scale (PANSS) was used to assess the improvement of psychopathological symptoms from the baseline to the end point in each subject. For better presentation of time-course changes in response status, a mixed model for repeated-measures (MMRM) analysis of symptom improvement during the 12-week treatment period was conducted. The change in plasma prolactin level after amisulpride treatment was also examined (n=51). No significant differences in the genotype frequencies of the COMT variants investigated were observed between responders and non-responders. Moreover, an MMRM analysis of psychopathological symptom improvement during the 12-week treatment course showed that it depended significantly on COMT variants (rs4680, rs4633, and rs6267), particularly regarding changes in negative symptoms. The increase in plasma prolactin levels observed was influenced by the COMT rs4680 variant and was positively correlated with a reduction in PANSS negative scores. Our results suggest that variation of the COMT gene is associated with treatment response regarding negative symptoms and prolactin changes after amisulpride treatment in patients with schizophrenia.

  3. How to consistently link extraversion and intelligence to the catechol-O-methyltransferase (COMT) gene: on defining and measuring psychological phenotypes in neurogenetic research.

    Science.gov (United States)

    Wacker, Jan; Mueller, Erik M; Hennig, Jürgen; Stemmler, Gerhard

    2012-02-01

    The evidence for associations between genetic polymorphisms and complex behavioral/psychological phenotypes (traits) has thus far been weak and inconsistent. Using the well-studied Val158Met polymorphism of the catechol-O-methyltransferase (COMT) gene as an example, we demonstrate that using theoretical models to guide phenotype definition and measuring the phenotypes of interest with a high degree of specificity reveals strong gene-behavior associations that are consistent with prior work and that would have otherwise gone unnoticed. Only after statistically controlling for irrelevant portions of phenotype variance did we observe strong (Cohen's d = 0.33-0.70) and significant associations between COMT Val158Met and both cognitive and affective traits in a healthy male sample (N = 201) in Study 1: Carriers of the Met allele scored higher in fluid intelligence (reasoning) but lower in both crystallized intelligence (general knowledge) and the agency facet of extraversion. In Study 2, we conceptually replicated the association of COMT Val158Met with the agency facet of extraversion after partialing irrelevant phenotype variance in a female sample (N = 565). Finally, through reanalysis of a large published data set we showed that Met allele carriers also scored higher in indicators of fluid intelligence after partialing verbal fluency. Because the Met allele codes for a less efficient variant of the enzyme COMT, resulting in higher levels of extrasynaptic prefrontal dopamine, these observations provide further support for a role for dopamine in both intelligence and extraversion. More importantly, the present findings have important implications for the definition of psychological phenotypes in neurogenetic research.

  4. The Cu-MOF-199/single-walled carbon nanotubes modified electrode for simultaneous determination of hydroquinone and catechol with extended linear ranges and lower detection limits

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jian [School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan 430070 (China); Li, Xi, E-mail: chemlixi@whut.edu.cn [School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan 430070 (China); Yang, Linlin; Yan, Songlin; Wang, Mengmeng; Cheng, Dan; Chen, Qi; Dong, Yulin; Liu, Peng; Cai, Weiquan [School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan 430070 (China); Zhang, Chaocan, E-mail: polymers@whut.edu.cn [School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070 (China)

    2015-10-29

    A novel electrochemical sensor based on Cu-MOF-199 [Cu-MOF-199 = Cu{sub 3}(BTC){sub 2} (BTC = 1,3,5-benzenetricarboxylicacid)] and SWCNTs (single-walled carbon nanotubes) was fabricated for the simultaneous determination of hydroquinone (HQ) and catechol (CT). The modification procedure was carried out through casting SWCNTs on the bare glassy carbon electrode (GCE) and followed by the electrodeposition of Cu-MOF-199 on the SWCNTs modified electrode. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) were performed to characterize the electrochemical performance and surface characteristics of the as-prepared sensor. The composite electrode exhibited an excellent electrocatalytic activity with increased electrochemical signals towards the oxidation of HQ and CT, owing to the synergistic effect of SWCNTs and Cu-MOF-199. Under the optimized condition, the linear response range were from 0.1 to 1453 μmol L{sup −1} (R{sub HQ} = 0.9999) for HQ and 0.1–1150 μmol L{sup −1} (R{sub CT} = 0.9990) for CT. The detection limits for HQ and CT were as low as 0.08 and 0.1 μmol L{sup −1}, respectively. Moreover, the modified electrode presented the good reproducibility and the excellent anti-interference performance. The analytical performance of the developed sensor for the simultaneous detection of HQ and CT had been evaluated in practical samples with satisfying results. - Highlights: • Cu-MOF-199/SWCNTs/GCE was facilely fabricated by the electrodeposition on SWCNTs/GCE. • An electrochemical sensor for detecting HQ and CT was constructed based on this modified electrode. • The proposed electrochemical sensor showed an extended linear range and lower detection limits. • The proposed electrochemical sensor had an excellent stability and reproducibility.

  5. Biopsychosocial Influence on Exercise-induced Delayed Onset Muscle Soreness at the Shoulder: Pain Catastrophizing and Catechol-O-Methyltransferase (COMT) Diplotype Predict Pain Ratings

    Science.gov (United States)

    George, Steven Z.; Dover, Geoffrey C.; Wallace, Margaret R.; Sack, Brandon K.; Herbstman, Deborah M.; Aydog, Ece; Fillingim, Roger B.

    2009-01-01

    Objective The experience of pain is believed to be influenced by psychologic and genetic factors. A previous study suggested pain catastrophizing and catechol-O-methyltransferase (COMT) genotype influenced clinical pain ratings for patients seeking operative treatment of shoulder pain. This study investigated whether these same psychologic and genetic factors predicted responses to induced shoulder pain. Methods Participants (n=63) completed self-report questionnaires and had COMT genotype determined before performing a standardized fatigue protocol to induce delayed onset muscle soreness. Then, shoulder pain ratings, self-report of upper-extremity disability ratings, and muscle torque production were reassessed 24, 48, and 72 hours later. Results This cohort consisted of 35 women and 28 men, with a mean age of 20.9 years (SD=1.7). The frequency of COMT diplotypes was 42 with “high COMT enzyme activity” (low pain sensitivity group) and 21 with “low COMT enzyme activity” (average pain sensitivity/high pain sensitivity group). A hierarchical regression model indicated that an interaction between pain catastrophizing and COMT diplotype was the strongest unique predictor of 72-hour pain ratings. The same interaction was not predictive of self-report of disability or muscle torque production at 72 hours. The pain catastrophizing × COMT diplotype interaction indicated that participants with high pain catastrophizing and low COMT enzyme activity (average pain sensitivity/high pain sensitivity group) were more likely (relative risk=3.5, P=0.025) to have elevated pain intensity ratings (40/100 or higher). Discussion These findings from an experimental model converge with those from a surgical cohort and provide additional evidence that the presence of elevated pain catastrophizing and COMT diplotype indicative of low COMT enzyme activity have the potential to increase the risk of developing chronic pain syndromes. PMID:18936597

  6. Departure from multiplicative interaction for catechol-O-methyltransferase genotype and active/passive exposure to tobacco smoke among women with breast cancer

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    Wilk Jemma

    2006-01-01

    Full Text Available Abstract Background Women with homozygous polymorphic alleles of catechol-O-methyltransferase (COMT-LL metabolize 2-hydroxylated estradiol, a suspected anticarcinogenic metabolite of estrogen, at a four-fold lower rate than women with no polymorphic alleles (COMT-HH or heterozygous women (COMT-HL. We hypothesized that COMT-LL women exposed actively or passively to tobacco smoke would have higher exposure to 2-hydroxylated estradiol than never-active/never passive exposed women, and should therefore have a lower risk of breast cancer than women exposed to tobacco smoke or with higher COMT activity. Methods We used a case-only design to evaluate departure from multiplicative interaction between COMT genotype and smoking status. We identified 502 cases of invasive incident breast cancer and characterized COMT genotype. Information on tobacco use and other potential breast cancer risk factors were obtained by structured interviews. Results We observed moderate departure from multiplicative interaction for COMT-HL genotype and history of ever-active smoking (adjusted odds ratio [aOR] = 1.6, 95% confidence interval [CI]: 0.7, 3.8 and more pronounced departure for women who smoked 40 or more years (aOR = 2.3, 95% CI: 0.8, 7.0. We observed considerable departure from multiplicative interaction for COMT-HL genotype and history of ever-passive smoking (aOR = 2.0, 95% CI: 0.8, 5.2 or for having lived with a smoker after age 20 (aOR = 2.8, 95% CI: 0.8, 10. Conclusion With greater control over potential misclassification errors and a large case-only population, we found evidence to support an interaction between COMT genotype and tobacco smoke exposure in breast cancer etiology.

  7. Effect of catechol-O-methyltransferase-val158met-polymorphism on the automatization of motor skills - a post hoc view on an experimental data.

    Science.gov (United States)

    Krause, Daniel; Beck, Frieder; Agethen, Manfred; Blischke, Klaus

    2014-06-01

    The purpose of this study was to evaluate if the catechol-O-methyltransferase-val158met (COMT)-polymorphism, which is known to affect prefrontal dopaminergic metabolism, affects the automatization of motor skills. Twenty-two participants volunteered for gene analysis after they had participated in experiments in which they practiced a single-joint arm movement sequence 460-760 times under different feedback conditions. Motor automaticity was assessed in a pre-test and a post-test according to the dual-task paradigm, which incorporated a visuo-spatial secondary task. To account for the different practice conditions in the four original studies, dual-task cost reduction was assessed using single case effect sizes proportioned to the respective group mean. For the secondary task but not for the prioritized motor task, these relative single case effect sizes proved to be positively (and significantly) correlated with the number of met-alleles on the COMT-genotype, rs=.553; p=.004. Thus, the number of met-alleles indicated a tendency toward enhanced motor automatization. Thus, due to an increased prefrontal dopamine level, met-carriers may be able to develop a well formed and stable, spatially coded movement representation early in practice, thereby supporting the formation of a representation in motor coordinates in the course of extended practice, which later enables automatic movement execution. This process might also be enhanced by a prevalence of met-carriers to functionally evaluate positive feedback information (i.e., rewards) and to better maintain recent reward information in active working memory.

  8. Catechol-O-methyltransferase Val158Met genotype in healthy and personality disorder individuals: Preliminary results from an examination of cognitive tests hypothetically differentially sensitive to dopamine functions

    Directory of Open Access Journals (Sweden)

    Winnie W Leung

    2007-01-01

    Full Text Available Winnie W Leung1, Margaret M McClure1, Larry J Siever1,2, Deanna M Barch3, Philip D Harvey1,21Department of Veterans Affairs, VISN 3 Mental Illness Research, Education, and Clinical Center (MIRECC, Bronx, NY, USA; 2Department of Psychiatry, Mt. Sinai School of Medicine, New York, NY, USA; 3Departments of Psychology and Psychiatry, Washington University, St. Louis, MO, USAAbstract: A functional polymorphism of the gene coding for Catechol-O-methyltrasferase (COMT, an enzyme responsible for the degradation of the catecholamine dopamine (DA, epinephrine, and norepinephrine, is associated with cognitive deficits. However, previous studies have not examined the effects of COMT on context processing, as measured by the AX-CPT, a task hypothesized to be maximally relevant to DA function. 32 individuals who were either healthy, with schizotypal personality disorder, or non-cluster A, personality disorder (OPD were genotyped at the COMT Val158Met locus. Met/Met (n = 6, Val/Met (n = 10, Val/Val (n = 16 individuals were administered a neuropsychological battery, including the AX-CPT and the N-back working memory test. For the AX-CPT, Met/Met demonstrated more AY errors (reflecting good maintenance of context than the other genotypes, who showed equivalent error rates. Val/Val demonstrated disproportionately greater deterioration with increased task difficulty from 0-back to 1-back working memory demands as compared to Met/Met, while Val/Met did not differ from either genotypes. No differences were found on processing speed or verbal working memory. Both context processing and working memory appear related to COMT genotype and the AX-CPT and N-back may be most sensitive to the effects of COMT variation.Keywords: COMT, dopamine, context processing, working memory, schizotypal personality disorder

  9. Assessment of cellular estrogenic activity based on estrogen receptor-mediated reduction of soluble-form catechol-O-methyltransferase (COMT) expression in an ELISA-based system.

    Science.gov (United States)

    Ho, Philip Wing-Lok; Tse, Zero Ho-Man; Liu, Hui-Fang; Lu, Song; Ho, Jessica Wing-Man; Kung, Michelle Hiu-Wai; Ramsden, David Boyer; Ho, Shu-Leong

    2013-01-01

    Xenoestrogens are either natural or synthetic compounds that mimic the effects of endogenous estrogen. These compounds, such as bisphenol-A (BPA), and phthalates, are commonly found in plastic wares. Exposure to these compounds poses major risk to human health because of the potential to cause endocrine disruption. There is huge demand for a wide range of chemicals to be assessed for such potential for the sake of public health. Classical in vivo assays for endocrine disruption are comprehensive but time-consuming and require sacrifice of experimental animals. Simple preliminary in vitro screening assays can reduce the time and expense involved. We previously demonstrated that catechol-O-methyltransferase (COMT) is transcriptionally regulated by estrogen via estrogen receptor (ER). Therefore, detecting corresponding changes of COMT expression in estrogen-responsive cells may be a useful method to estimate estrogenic effects of various compounds. We developed a novel cell-based ELISA to evaluate cellular response to estrogenicity by reduction of soluble-COMT expression in ER-positive MCF-7 cells exposed to estrogenic compounds. In contrast to various existing methods that only detect bioactivity, this method elucidates direct physiological effect in a living cell in response to a compound. We validated our assay using three well-characterized estrogenic plasticizers - BPA, benzyl butyl phthalate (BBP), and di-n-butyl phthalate (DBP). Cells were exposed to either these plasticizers or 17β-estradiol (E2) in estrogen-depleted medium with or without an ER-antagonist, ICI 182,780, and COMT expression assayed. Exposure to each of these plasticizers (10(-9)-10(-7)M) dose-dependently reduced COMT expression (pvitro assays of similar sensitivity. To satisfy the demand for in vitro assays targeting different cellular components, a cell-based COMT assay provides useful initial screening to supplement the current assessments of xenoestrogens for potential estrogenic activity.

  10. Synthesis of a water-soluble analog of 6-methyl-3-N-alkyl catechol labeled with carbon 13: NMR approach to the reactivity of poison ivy/oak sensitizers toward proteins.

    Science.gov (United States)

    Goetz, G; Meschkat, E; Lepoittevin, J P

    1999-04-19

    A 13-C labeled water soluble derivative of alkylcatechol was synthesized and reacted with human serum albumin in phosphate buffer at pH 7.4 in air to allow a slow oxidation of the catechol into orthoquinone. The formation of several adducts was evidenced by a combination of 13C and 1H-13C correlation NMR. Although some adducts could result from a classical o-quinone formation - Michael type addition, our results suggest that a second pathway, involving a direct reaction of a carbon centered radical with proteins could be an important mechanism in the formation of modified proteins.

  11. (1)H, (15)N, (13)C backbone resonance assignments of human soluble catechol O-methyltransferase in complex with S-adenosyl-L-methionine and 3,5-dinitrocatechol.

    Science.gov (United States)

    Czarnota, Sylwia; Baxter, Nicola J; Cliff, Matthew J; Waltho, Jonathan P; Scrutton, Nigel S; Hay, Sam

    2016-12-15

    Catechol O-methyltransferase (COMT) is an enzyme that plays a major role in catechol neurotransmitter deactivation. Inhibition of COMT can increase neurotransmitter levels, which provides a means of treatment for Parkinson's disease, schizophrenia and depression. COMT exists as two isozymes: a soluble cytoplasmic form (S-COMT), expressed in the liver and kidneys and a membrane-bound form (MB-COMT), found mostly in the brain. Here we report the backbone (1)H, (15)N and (13)C chemical shift assignments of S-COMT in complex with S-adenosyl-L-methionine, 3,5-dinitrocatechol and Mg(2+). Assignments were obtained by heteronuclear multidimensional NMR spectroscopy. In total, 97 % of all backbone resonances were assigned in the complex, with 205 out of a possible 215 residues assigned in the (1)H-(15)N TROSY spectrum. Prediction of solution secondary structure from a chemical shift analysis using the TALOS+ webserver is in good agreement with published X-ray crystal structures.

  12. Differential Effects of the Catechol-O-Methyltransferase Val158Met Genotype on the Cognitive Function of Schizophrenia Patients and Healthy Japanese Individuals

    Science.gov (United States)

    Tsuchimine, Shoko; Yasui-Furukori, Norio; Kaneda, Ayako; Kaneko, Sunao

    2013-01-01

    Background The functional polymorphism Val158Met in the catechol-O-methyltransferase (COMT) gene has been associated with differences in prefrontal cognitive functions in patients with schizophrenia and healthy individuals. Several studies have indicated that the Met allele is associated with better performance on measures of cognitive function. We investigated whether the COMT Val158Met genotype was associated with cognitive function in 149 healthy controls and 118 patients with schizophrenia. Methods Cognitive function, including verbal memory, working memory, motor speed, attention, executive function and verbal fluency, was assessed by the Brief Assessment of Cognition in Schizophrenia (BACS-J). We employed a one-way analysis of variance (ANOVA) and a multiple regression analysis to determine the associations between the COMT Val158Met genotype and the BACS-J measurements. Results The one-way ANOVA revealed a significant difference in the scores on the Tower of London, a measure of executive function, between the different Val158Met genotypes in the healthy controls (p = 0.023), and a post-hoc analysis showed significant differences between the scores on the Tower of London in the val/val genotype group (18.6 ± 2.4) compared to the other two groups (17.6 ± 2.7 for val/met and 17.1 ± 3.2 for met/met; p = 0.027 and p = 0.024, respectively). Multiple regression analyses revealed that executive function was significantly correlated with the Val158Met genotype (p = 0.003). However, no evidence was found for an effect of the COMT on any cognitive domains of the BACS-J in the patients with schizophrenia. Conclusion These data support the hypothesis that the COMT Val158Met genotype maintains an optimal level of dopamine activity. Further studies should be performed that include a larger sample size and include patients on and off medication, as these patients would help to confirm our findings. PMID:24282499

  13. Assessment of cellular estrogenic activity based on estrogen receptor-mediated reduction of soluble-form catechol-O-methyltransferase (COMT expression in an ELISA-based system.

    Directory of Open Access Journals (Sweden)

    Philip Wing-Lok Ho

    Full Text Available Xenoestrogens are either natural or synthetic compounds that mimic the effects of endogenous estrogen. These compounds, such as bisphenol-A (BPA, and phthalates, are commonly found in plastic wares. Exposure to these compounds poses major risk to human health because of the potential to cause endocrine disruption. There is huge demand for a wide range of chemicals to be assessed for such potential for the sake of public health. Classical in vivo assays for endocrine disruption are comprehensive but time-consuming and require sacrifice of experimental animals. Simple preliminary in vitro screening assays can reduce the time and expense involved. We previously demonstrated that catechol-O-methyltransferase (COMT is transcriptionally regulated by estrogen via estrogen receptor (ER. Therefore, detecting corresponding changes of COMT expression in estrogen-responsive cells may be a useful method to estimate estrogenic effects of various compounds. We developed a novel cell-based ELISA to evaluate cellular response to estrogenicity by reduction of soluble-COMT expression in ER-positive MCF-7 cells exposed to estrogenic compounds. In contrast to various existing methods that only detect bioactivity, this method elucidates direct physiological effect in a living cell in response to a compound. We validated our assay using three well-characterized estrogenic plasticizers - BPA, benzyl butyl phthalate (BBP, and di-n-butyl phthalate (DBP. Cells were exposed to either these plasticizers or 17β-estradiol (E2 in estrogen-depleted medium with or without an ER-antagonist, ICI 182,780, and COMT expression assayed. Exposure to each of these plasticizers (10(-9-10(-7M dose-dependently reduced COMT expression (p<0.05, which was blocked by ICI 182,780. Reduction of COMT expression was readily detectable in cells exposed to picomolar level of E2, comparable to other in vitro assays of similar sensitivity. To satisfy the demand for in vitro assays targeting different

  14. Dopamine D3 Receptor Ser9Gly and Catechol-O-methyltransferase Val158Met Polymorphisms and Acute Pain in Sickle Cell Disease

    Science.gov (United States)

    Jhun, Ellie; He, Ying; Yao, Yingwei; Molokie, Robert E.; Wilkie, Diana J.; Wang, Zaijie Jim

    2014-01-01

    Background Pain in sickle cell disease (SCD) is characterized by episodes of acute pain, primarily responsible for acute health care utilization, and persistent chronic pain. Pain severity and frequency vary significantly among SCD patients. In this study, we investigated the possible contribution of monoamine gene polymorphisms to pain variation. Methods Adult subjects with SCD completed PAINReportIt®, a computerized McGill Pain Questionnaire, from which we calculated the Composite Pain Index. Utilization data were obtained from the medical record and biweekly telephone calls for 12 months. Utilization is defined as admissions to the emergency department and/or the acute care center resulting from a sickle cell pain crisis. We performed genotyping for catechol-O-methyltransferase (COMT) Val158Met (rs4680) and dopamine D3 receptor(DRD3) Ser9Gly (rs6280) polymorphisms, which were analyzed for associations with pain phenotypes. Results Binary logistic models revealed that DRD3 Ser9Gly heterozygote patients were more likely not to have an acute pain crisis (odds ratio [OR] [95% confidence interval (CI)], 4.37 [1.39, 22.89]; p=0.020), which remained so when demographic variables were considered (OR [95% CI], 4.53 [1.41, 28.58]; p=0.016). COMT Val158Met Met allele showed lower probability for zero utilization (OR [95% CI], 0.32 [0.12, 0.83]; p=0.020) than the Val allele. In the negative binomial regression analysis, subjects with COMT Met/Met genotype had utilization incident rate ratio [95% CI] of 2.20 [1.21, 3.99] over those with Val/Val (p=0.010). Conclusions These exploratory findings suggest that DRD3 Ser9Gly and COMT Val158Met may contribute to pain heterogeneity in SCD, as suggested by the different rates of acute pain crisis. Specifically, SCD patients with the DRD3 homozygote genotypes, COMT 158 Met allele or Met/Met genotype are more likely to have acute care utilization, an indicator of acute pain. These results, however, will need to be further examined in

  15. Differential effects of the catechol-O-methyltransferase Val158Met genotype on the cognitive function of schizophrenia patients and healthy Japanese individuals.

    Directory of Open Access Journals (Sweden)

    Shoko Tsuchimine

    Full Text Available BACKGROUND: The functional polymorphism Val158Met in the catechol-O-methyltransferase (COMT gene has been associated with differences in prefrontal cognitive functions in patients with schizophrenia and healthy individuals. Several studies have indicated that the Met allele is associated with better performance on measures of cognitive function. We investigated whether the COMT Val158Met genotype was associated with cognitive function in 149 healthy controls and 118 patients with schizophrenia. METHODS: Cognitive function, including verbal memory, working memory, motor speed, attention, executive function and verbal fluency, was assessed by the Brief Assessment of Cognition in Schizophrenia (BACS-J. We employed a one-way analysis of variance (ANOVA and a multiple regression analysis to determine the associations between the COMT Val158Met genotype and the BACS-J measurements. RESULTS: The one-way ANOVA revealed a significant difference in the scores on the Tower of London, a measure of executive function, between the different Val158Met genotypes in the healthy controls (p = 0.023, and a post-hoc analysis showed significant differences between the scores on the Tower of London in the val/val genotype group (18.6 ± 2.4 compared to the other two groups (17.6 ± 2.7 for val/met and 17.1 ± 3.2 for met/met; p = 0.027 and p = 0.024, respectively. Multiple regression analyses revealed that executive function was significantly correlated with the Val158Met genotype (p = 0.003. However, no evidence was found for an effect of the COMT on any cognitive domains of the BACS-J in the patients with schizophrenia. CONCLUSION: These data support the hypothesis that the COMT Val158Met genotype maintains an optimal level of dopamine activity. Further studies should be performed that include a larger sample size and include patients on and off medication, as these patients would help to confirm our findings.

  16. Relation between the catalytic efficiency of the synthetic analogues of catechol oxidase with their electrochemical property in the free state and substrate-bound state.

    Science.gov (United States)

    Chakraborty, Prateeti; Adhikary, Jaydeep; Ghosh, Bipinbihari; Sanyal, Ria; Chattopadhyay, Shyamal Kumar; Bauzá, Antonio; Frontera, Antonio; Zangrando, Ennio; Das, Debasis

    2014-08-18

    A library of 15 dicopper complexes as synthetic analogues of catechol oxidase has been synthesized with the aim to determine the relationship between the electrochemical behavior of the dicopper(II) species in the absence as well as in the presence of 3,5-di-tert-butylcatechol (3,5-DTBC) as model substrate and the catalytic activity, kcat, in DMSO medium. The complexes have been characterized by routine physicochemical techniques as well as by X-ray single-crystal structure analysis in some cases. Fifteen "end-off" compartmental ligands have been designed as 1 + 2 Schiff-base condensation product of 2,6-diformyl-4-R-phenol (R = Me, (t)Bu, and Cl) and five different amines, N-(2-aminoethyl)piperazine, N-(2-aminoethyl)pyrrolidine, N-(2-aminoethyl)morpholine, N-(3-aminopropyl)morpholine, and N-(2-aminoethyl)piperidine. Interestingly, in case of the combination of 2,6-diformyl-4-methylphenol and N-(2-aminoethyl)morpholine/N-(3-aminopropyl)morpholine/N-(2-aminoethyl)piperidine 1 + 1 condensation becomes the reality and the ligands are denoted as L2(1-3). On reaction of copper(II) nitrate with L2(1-3) in situ complexes 3, 12, and 13 are formed having general formula Cu2(L2(1-3))2(NO3)2. The remaining 12 ligands obtained as 1 + 2 condensation products are denoted as L1(1-12), which produce complexes having general formula Cu2(L1(1-12))(NO3)2. Catecholase activity of all 15 complexes has been investigated in DMSO medium using 3,5-DTBC as model substrate. Treatment on the basis of Michaelis-Menten model has been applied for kinetic study, and thereby turnover number, kcat, values have been evaluated. Cyclic voltametric (CV) and differential pulse voltametric (DPV) studies of the complexes in the presence as well as in the absence of 3,5-DTBC have been thoroughly investigated in DMSO medium. From those studies it is evident that oxidation of 3,5-DTBC catalyzed by dicopper(II) complexes proceed via two steps: first, semibenzoquinone followed by benzoquinone with concomitant

  17. Systemic catechol-O-methyl transferase inhibition enables the D{sub 1} agonist radiotracer R-[{sup 11}C]SKF 82957

    Energy Technology Data Exchange (ETDEWEB)

    Palner, Mikael, E-mail: mikael.palner@nru.d [Neurobiology Research Unit, Rigshospitalet and University of Copenhagen, Copenhagen (Denmark); Center for Integrated Molecular Brain Imaging, Rigshospitalet (Denmark); McCormick, Patrick; Parkes, Jun [PET Center, Center for Addiction and Mental Health, Toronto, Ontario (Canada); Knudsen, Gitte M. [Neurobiology Research Unit, Rigshospitalet and University of Copenhagen, Copenhagen (Denmark); Center for Integrated Molecular Brain Imaging, Rigshospitalet (Denmark); Wilson, Alan A. [PET Center, Center for Addiction and Mental Health, Toronto, Ontario (Canada); Department of Psychiatry, University of Toronto, Toronto, Ontario (Canada)

    2010-10-15

    Introduction: R-[{sup 11}C]-SKF 82957 is a high-affinity and potent dopamine D{sub 1} receptor agonist radioligand, which gives rise to a brain-penetrant lipophilic metabolite. In this study, we demonstrate that systemic administration of catechol-O-methyl transferase (COMT) inhibitors blocks this metabolic pathway, facilitating the use of R-[{sup 11}C]-SKF 82957 to image the high-affinity state of the dopamine D{sub 1} receptor with PET. Methods: R-[{sup 11}C]SKF 82957 was administered to untreated and COMT inhibitor-treated conscious rats, and the radioactive metabolites present in the brain and plasma were quantified by HPLC. Under optimal conditions, cerebral uptake and dopamine D{sub 1} binding of R-[{sup 11}C]SKF 82957 were measured ex vivo. In addition, pharmacological challenges with the receptor antagonist SCH 23390, amphetamine, the dopamine reuptake inhibitor RTI-32 and the dopamine hydroxylase inhibitor {alpha}-methyl-p-tyrosine were performed to study the specificity and sensitivity of R-[{sup 11}C]-SKF 82957 dopamine D{sub 1} binding in COMT-inhibited animals. Results: Treatment with the COMT inhibitor tolcapone was associated with a dose-dependent (EC{sub 90} 5.3{+-}4.3 mg/kg) reduction in the lipophilic metabolite. Tolcapone treatment (20 mg/kg) also resulted in a significant increase in the striatum/cerebellum ratio of R-[{sup 11}C]SKF 82957, from 15 (controls) to 24. Treatment with the dopamine D{sub 1} antagonist SCH 23390 reduced the striatal binding to the levels of the cerebellum, demonstrating a high specificity and selectivity of R-[{sup 11}C]SKF 82957 binding. Conclusions: Pre-treatment with the COMT inhibitor tolcapone inhibits formation of an interfering metabolite of R-[{sup 11}C]SKF 82957. Under such conditions, R-[{sup 11}C]SKF 82957 demonstrates high potential as the first agonist radiotracer for imaging the dopamine D{sub 1} receptor by PET.

  18. 对甲苯磺酸盐作为两相催化剂催化邻苯二酚与羰基化合物的缩合%Ketalization of Catechol with Carbonyl Compounds Catalyzed by Metal p-Toluenesulfonate as Biphasic Acid Catalyst

    Institute of Scientific and Technical Information of China (English)

    梁学正; 高珊; 王雯娟; 程文萍; 杨建国

    2008-01-01

    Ketalization of catechol was studied with various carbonyl compounds using metal p-toluenesulfonate as biphasic catalysts. The results showed that copper p-toluenesulfonate was the most efficient catalysts for the re-action. The advantages of high activity, stability, reusability and low cost for the simple synthetic procedure made the catalyst one of the best choice for the reaction.

  19. Identification and characterization of a catechol-o-methyltransferase cDNA in the catfish Heteropneustes fossilis: Tissue, sex and seasonal variations, and effects of gonadotropin and 2-hydroxyestradiol-17β on mRNA expression.

    Science.gov (United States)

    Chaube, R; Rawat, A; Inbaraj, R M; Bobe, J; Guiguen, Y; Fostier, A; Joy, K P

    2016-12-08

    Catechol-O-methyltransferase (COMT) is involved in the methylation and inactivation of endogenous and xenobiotic catechol compounds, and serves as a common biochemical link in the catecholamine and catecholestrogen metabolism. Studies on cloning, sequencing and function characterization comt gene in lower vertebrates like fish are fewer. In the present study, a full-length comt cDNA of 1442bp with an open-reading frame (ORF) of 792bp, and start codon (ATG) at nucleotide 162 and stop codon (TAG) at nucleotide 953 was isolated and characterized in the stinging catfish Heteropneustes fossilis (accession No. KT597925). The ORF codes for a protein of 263 amino acid residues, which is also validated by the catfish transcriptome data analysis. The catfish Comt shared conserved putative structural regions important for S-adenosyl methionine (AdoMet)- and catechol-binding, transmembrane regions, two glycosylation sites (N-65 and N-91) at the N-terminus and two phosphorylation sites (Ser-235 and Thr-240) at the C-terminus. The gene was expressed in all tissues examined and the expression showed significant sex dimorphic distribution with high levels in females. The transcript was abundant in the liver, brain and gonads and low in muscles. The transcripts showed significant seasonal variations in the brain and ovary, increased progressively to the peak levels in spawning phase and then declined. The brain and ovarian comt mRNA levels showed periovulatory changes after in vivo and in vitro human chorionic gonadotropin (hCG) treatments with high fold increases at 16 and 24h in the brain and at 16h in the ovary. The catecholestrogen 2-hydroxyE2 up regulated ovarian comt expression in vitro with the highest fold increase at 16h. The mRNA and protein was localized in the follicular layer of the vitellogenic follicles and in the cytoplasm of primary follicles. The data were discussed in relation to catecholamine and catecholestrogen-mediated functions in the brain and ovary of the

  20. 邻苯二酚?Fe2O3和邻苯二酚?CuO体系中持久性自由基的形成机制及特征%The formation and characteristics of persistent free radicals in catechol?Fe2O3/silica and catechol?CuO/silica systems

    Institute of Scientific and Technical Information of China (English)

    王婷; 李浩; 郭惠莹; 程正奇; 潘波

    2016-01-01

    This work studied the formation mechanism and characteristics of PFRs in the system of catechol(CT)?Fe2O3/SiO2 and CT?CuO/SiO2. Importantly, the impact of PFRs on CT degradation was investigated. Compared to CT?SiO2 particles, more stable PFRs were observed during the interaction between CT and transition metal on the surface of 1% Fe2 O3/SiO2 or 1% CuO/SiO2 particles. These PFRs are mostly semiquinone free radicals with a g factor of 2.0040—2.0055. The generation of Fe (Ⅱ)?PFRs or Cu (Ⅰ)?PFRs decreased the degradation of CT in the lower concentration and thus might alter CT environmental behavior and increase its environmental risk.%以SiO2为载体模拟固体土壤环境,研究了邻苯二酚(CT)?Fe2 O3/SiO2和CT?CuO/SiO2体系中持久性自由基(PFRs)的形成机制、特征及其对邻苯二酚降解的影响.实验发现,相对于CT?SiO2体系,CT?Fe2 O3/SiO2和CT?CuO/SiO2体系中邻苯二酚和过渡金属相互作用,还原后的过渡金属与自由基结合形成了以半醌自由基为主的更稳定的PFRs,其g值为2.0040—2.0055.在较低浓度时,这种PFRs阻碍了CT的降解,改变了其环境行为,增大了其环境风险.

  1. Impact of deformation energy on the hydrogen bonding interactions in gas phase 3-X catechol ⋯ H2O complexes (X = H, F, Cl, Br): The effect of approach of a water molecule

    Science.gov (United States)

    Deb, Debojit Kumar; Sarkar, Biplab

    2016-06-01

    The conformations and nature of hydrogen bonding interactions for 3-X catechol ⋯ H2O (X = H, F, Cl, Br) has been investigated by ab initio MP2, CCSD(T), and density functional B3LYP, wB97XD and M06-2X methods. The changes in interaction energies due to deformation of the structures has been studied in detail. The intra- and intermolecular hydrogen bonding interactions due to the different direction of approach of water molecule have been discussed. A detailed natural bond orbital (NBO) analysis and the symmetry-adapted perturbation theory (SAPT) based energy decomposition analysis has been carried out to elucidate interaction strength and properties in these hydrogen bonded systems. The charge transfer percentage (CTP) has been derived which will be universally useful for correlating binding energy, deformation energy and the geometrical parameters such as angles, bond lengths, etc. for other systems as well.

  2. Preparation and characterization of Ba{sub 1-x}Sr{sub x}TiO{sub 3} (x=0.1, 0.2) fibers by sol-gel process using catechol-complexed titanium isopropoxide

    Energy Technology Data Exchange (ETDEWEB)

    Lu Qifang; Chen Dairong; Jiao Xiuling

    2003-08-25

    Sol-gel synthesis of Ba{sub 1-x}Sr{sub x}TiO{sub 3} (x=0.1, 0.2) ceramic fibers with a diameter of 6-10 {mu}m using catechol-complexed titanium isopropoxide, barium acetate hydrate and strontium acetate hydrate as precursors has been investigated. The green fibers and those sintered at different temperatures were characterized by thermogravimetry analysis (TGA), infrared spectroscopy (IR), X-ray diffraction (XRD) and scanning electron microscope (SEM) techniques. Microstructural development of barium strontium titanate (Ba{sub 1-x}Sr{sub x}TiO{sub 3}) ceramic fibers as a function of strontium concentrations was studied. X-ray diffraction indicated that the well-developed cubic phase of (Ba, Sr)TiO{sub 3} was crystallized at 1100 deg. C.

  3. Genetic Variation in the Catechol-O-Methyl Transferase Val108/158Met Is Linked to the Caudate and Posterior Cingulate Cortex Volume in Healthy Subjects: Voxel-Based Morphometry Analysis of Brain Magnetic Resonance Imaging

    Science.gov (United States)

    Watanabe, Keita; Kakeda, Shingo; Yoshimura, Reiji; Ide, Satoru; Hayashi, Kenji; Katsuki, Asuka; Umene-Nakano, Wakako; Watanabe, Rieko; Abe, Osamu; Korogi, Yukunori

    2015-01-01

    The effect of the catechol-O-methyltransferase (COMT) Val158Met polymorphism on brain morphology has been investigated but remains controversial. We hypothesized that a comparison between Val/Val and Val/Met individuals, which may represent the most different combinations concerning the effects of the COMT genotype, may reveal new findings. We investigated the brain morphology using 3-Tesla magnetic resonance imaging in 27 Val/Val and 22 Val/Met individuals. Voxel-based morphometry revealed that the volumes of the bilateral caudate and posterior cingulate cortex were significantly smaller in Val/Val individuals than in Val/Met individuals [right caudate: false discovery rate (FDR)-corrected p = 0.048; left caudate: FDR-corrected p = 0.048; and bilateral posterior cingulate cortex: FDR-corrected p = 0.048]. This study demonstrates that interacting functional variants of COMT affect gray matter regional volumes in healthy subjects. PMID:26566126

  4. 海洛因依赖与儿茶酚胺氧位甲基转移酶基因的关联研究%Association study of heroin dependence and catechol-O-methyltransferase gene

    Institute of Scientific and Technical Information of China (English)

    曹莉萍; 李涛; 刘协和

    2003-01-01

    目的探讨海洛因依赖和儿茶酚胺氧位甲基转移酶(catechol-O-methyltransferase, COMT)基因的关系. 方法应用聚合酶链反应技术检测313例海洛因依赖者和214名正常对照COMT基因108 val/met和900 Ins C/Del C两个多态性. 结果海洛因依赖者和对照组之间上述两个多态性的基因型和等位基因频率的差异均无显著性(P>0.05). 结论 COMT基因108 val/met和900 Ins C/Del C两个多态性均与海洛因依赖无关联.

  5. Genetic Variation in the Catechol-O-Methyl Transferase Val108/158Met Is Linked to the Caudate and Posterior Cingulate Cortex Volume in Healthy Subjects: Voxel-Based Morphometry Analysis of Brain Magnetic Resonance Imaging.

    Directory of Open Access Journals (Sweden)

    Keita Watanabe

    Full Text Available The effect of the catechol-O-methyltransferase (COMT Val158Met polymorphism on brain morphology has been investigated but remains controversial. We hypothesized that a comparison between Val/Val and Val/Met individuals, which may represent the most different combinations concerning the effects of the COMT genotype, may reveal new findings. We investigated the brain morphology using 3-Tesla magnetic resonance imaging in 27 Val/Val and 22 Val/Met individuals. Voxel-based morphometry revealed that the volumes of the bilateral caudate and posterior cingulate cortex were significantly smaller in Val/Val individuals than in Val/Met individuals [right caudate: false discovery rate (FDR-corrected p = 0.048; left caudate: FDR-corrected p = 0.048; and bilateral posterior cingulate cortex: FDR-corrected p = 0.048]. This study demonstrates that interacting functional variants of COMT affect gray matter regional volumes in healthy subjects.

  6. Determination of Aluminium in Water Samples by Alizarin Red Spectrophotometry after Solid Phase Extraction on XAD-2-Catechol Resin%邻苯二酚螯合树脂的合成及水样中铝的测定

    Institute of Scientific and Technical Information of China (English)

    于涛; 耿伟; 杨枝; 曹维鹏

    2006-01-01

    合成并表征了新螯合树脂--邻苯二酚螯合树脂(XAD-2-Catechol),研究了XAD-2-Catechol吸附铝的特性和茜素红-铝的显色反应,在pH4. 5的HAc-NaAc缓冲介质中,茜素红和铝(Ⅲ)反应生成红色络合物,λmax=500 nm,铝的含量在0-50 μg/25 mL内符合比耳定律.建立了邻苯二酚螯合树脂分离/富集-茜素红分光光度法测定天然水样中铝的新方法,对水样中铝形态进行测定,结果满意.

  7. Effects of structural isomerism on solution behaviour of solutes: Apparent molar volumes and isentropic compression of catechol, resorcinal, and hydroquinone in aqueous solution at T = (283.15, 293.15, 298.15, 303.15, and 313.15) K

    Energy Technology Data Exchange (ETDEWEB)

    Bayram, Edip [Department of Chemistry, Akdeniz University, Antalya 07058 (Turkey); Ayranci, Erol, E-mail: eayranci@akdeniz.edu.t [Department of Chemistry, Akdeniz University, Antalya 07058 (Turkey)

    2010-09-15

    Effects of structural isomerism on solution behaviour of dihydroxybenzenes were examined through the determination of volumetric properties such as apparent molar volumes, apparent molar isentropic compressions, and isobaric expansions. The isomers were 1,2-dihydroxybenzene (catechol), 1,3-dihydroxybenzene (resorcinol), and 1,4-dihydroxybenzene (hydroquinone). The volumetric properties were determined from accurate density and speed of sound measurements at T = (283.15, 293.15, 298.15, 303.15, and 313.15) K and at various concentrations. Values at infinite dilution of these parameters were obtained by suitable extrapolation procedures. The results are discussed in terms of hydrophobic, hydrogen bon