WorldWideScience

Sample records for catechols

  1. How Many Drugs Are Catecholics

    Directory of Open Access Journals (Sweden)

    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. Heterogeneous Oxidation of Catechol.

    Science.gov (United States)

    Pillar, Elizabeth A; Zhou, Ruixin; Guzman, Marcelo I

    2015-10-15

    Natural and anthropogenic emissions of aromatic hydrocarbons from biomass burning, agro-industrial settings, and fossil fuel combustion contribute precursors to secondary aerosol formation (SOA). How these compounds are processed under humid tropospheric conditions is the focus of current attention to understand their environmental fate. This work shows how catechol thin films, a model for oxygenated aromatic hydrocarbons present in biomass burning and combustion aerosols, undergo heterogeneous oxidation at the air-solid interface under variable relative humidity (RH = 0-90%). The maximum reactive uptake coefficient of O3(g) by catechol γO3 = (7.49 ± 0.35) × 10(-6) occurs for 90% RH. Upon exposure of ca. 104-μm thick catechol films to O3(g) mixing ratios between 230 ppbv and 25 ppmv, three main reaction pathways are observed. (1) The cleavage of the 1,2 carbon-carbon bond at the air-solid interface resulting in the formation of cis,cis-muconic acid via primary ozonide and hydroperoxide intermediates. Further direct ozonolysis of cis,cis-muconic yields glyoxylic, oxalic, crotonic, and maleic acids. (2) A second pathway is evidenced by the presence of Baeyer-Villiger oxidation products including glutaconic 4-hydroxy-2-butenoic and 5-oxo-2-pentenoic acids during electrospray ionization mass spectrometry (MS) and ion chromatography MS analyses. (3) Finally, indirect oxidation by in situ produced hydroxyl radical (HO(•)) results in the generation of semiquinone radical intermediates toward the synthesis of polyhydoxylated aromatic rings such as tri-, tetra-, and penta-hydroxybenzene. Remarkably, heavier polyhydroxylated biphenyl and terphenyl products present in the extracted oxidized films result from coupling reactions of semiquinones of catechol and its polyhydroxylated rings. The direct ozonolysis of 1,2,3- and 1,2,4-trihydroxybenezene yields 2- and 3-hydroxy-cis,cis-muconic acid, respectively. The production of 2,4- or 3,4-dihdroxyhex-2-enedioic acid is

  3. Sensitive radioenzymatic assay for catechol drugs

    International Nuclear Information System (INIS)

    This assay measures picogram quantities of catechol drugs and endogenous catecholamines in body tissues and fluids. The catechols are converted to their 3H-O-methyl metabolites during incubation with 3H-S-adenosylmethionine then separated by solvent extraction and thin-layer chromatography. Most drugs containing the catechol structure can be radiolabeled and separated from norepinephrine and epinephrine by this technique to provide simultaneous measurement of endogenous and exogenously administered catechols. The disposition of isoproterenol in tissues and fluids of man and experimental animals is measured to illustrate the utility of this assay. The reactivity of several commonly administered catechol drugs with COMT is described and the possible implications discussed

  4. Catechols as versatile platforms in polymer chemistry

    OpenAIRE

    Faure, Emilie; Falentin-Daudré, Céline; Jérôme, Christine; Lyskawa, Joël; Fournier, David; Woisel, Patrice; Detrembleur, Christophe

    2013-01-01

    Catechols represent an important and versatile building block for the design of mussel-inspired synthetic adhesives and coatings. Indeed, their ability to establish large panoply of interactions with both organic and inorganic substrates has promoted catechol as a universal anchor for surface modifications. In addition to its pivotal role in adhesive interfaces, the catechol unit recently emerged as a powerful building block for the preparation of a large range of polymeric materials with int...

  5. Bioinspired catecholic chemistry for surface modification.

    Science.gov (United States)

    Ye, Qian; Zhou, Feng; Liu, Weimin

    2011-07-01

    The attachment strategy based on catecholic chemistry has been arousing renewed interest since the work on polymerized catecholic amine (polydopamine) (Messersmith et al., Science, 2007, 318, 426) was published. Catechols and their derived compounds can self-assemble on various inorganic and organic materials, including noble metals, metals, metal oxides, mica, silica, ceramics and even polymers. It opens a new route to the modification of various substrates and the preparation of functional composite materials by simple chemistry. However, there is still not a full review so far about the attachment chemistry despite the dramatically increasing number of publications. This critical review describes the state-of-the-art research in the area: the design and synthesis of catecholic molecules, their adsorption mechanisms and the stability of assemblies in solution, and their applications etc. Some perspectives on future development are raised (195 references). PMID:21603689

  6. Catechol-O-Methyltransferase Polymorphism and Endometriosis

    OpenAIRE

    Wieser, Fritz; Wenzl, Rene; Tempfer, Clemens; Worda, Christoph; Huber, Johannes; Schneeberger, Christian

    2002-01-01

    Purpose: Catechol-O-methyltransferase (COMT) inactivates the estradiol metabolites, 2-hydroxy and 4-hydroxy catechols, which have been implicated in the pathogenesis of endometriosis. A COMT valine to methionine polymorphism (G-to-A) in exon 4 of the COMT gene is polymorphic in the human population, with 25% of Caucasians being homozygous for the low-activity allele (COMT-L) of the enzyme. In a case-control study we investigated whether this COMT polymorphism is associated with endometriosis.

  7. Boronate Derivatives of Functionally Diverse Catechols: Stability Studies

    Directory of Open Access Journals (Sweden)

    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

    Energy Technology Data Exchange (ETDEWEB)

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

    International Nuclear Information System (INIS)

    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

  10. Nitroderivatives of catechol: from synthesis to application.

    Science.gov (United States)

    Gavazov, Kiril B

    2012-03-01

    Nitroderivatives of catechol (NDCs) are reviewed with special emphasis on their complexes and applications. Binary, ternary and quaternary NDC complexes with more than 40 elements (aluminum, arsenic, boron, beryllium, calcium, cobalt, copper, iron, gallium, germanium, magnesium, manganese, molybdenum, niobium, rare earth elements, silicon, tin, strontium, technetium, thallium, titanium, uranium, vanadium, tungsten, zinc and zirconium) are discussed and the key characteristics of the developed analytical procedures - tabulated. The bibliography includes 206 references. PMID:24061167

  11. CATECHOL-O-METHYL TRANSFERASE AND SCHIZOPHRENIA

    OpenAIRE

    Šagud, Marina; Műck-Šeler, Dorotea; Mihaljević-Peleš, Alma; Vuksan-Ćusa, Bjanka; Živković, Maja; Jakovljević, Miro; Pivac, Nela

    2010-01-01

    Catechol-O-methyl transferase (COMT) is an enzyme involved in the degradation of dopamine. The most commonly examined polymorphism within the COMT gene is Val108/158Met polymorphism, which results in three to fourfold difference in COMT enzyme activity. It is particularely important in prefrontal cortex, since COMT activity is the most important regulator of the prefrontal dopamine function. Given the association between schizophrenia and decreased dopamine activity in the prefrontal corte...

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

    OpenAIRE

    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. Catechol oxidase is a type-3 copper enzyme usually encountered in plants and in some crustaceans, which catalyzes a conversion of a wide range of o-diphenols (catechols) to the respective o-benzoq...

  13. Biobased Polymer Coating Using Catechol Derivative Urushiol.

    Science.gov (United States)

    Watanabe, Hirohmi; Fujimoto, Aya; Nishida, Jin; Ohishi, Tomoyuki; Takahara, Atsushi

    2016-05-10

    We have investigated the mechanism of the superior mechanical robustness of coated thin films of the catechol derivative urushiol. We synthesized hydrogenated urushiol (h-urushiol) by hydrogenating the double bonds in the long alkyl side chain of urushiol, and the physical properties of thin films of mixtures of urushiol and h-urushiol were evaluated. Atomic force microscopy observations revealed that these coated thin films have a homogeneous surface with no phase separation, regardless of the h-urushiol content, arising from the similarity of the chemical structures. The films showed good adhesive properties because the adhesion originates from the catechol structure. In contrast, curing time depended strongly upon the h-urushiol content. The curing of the h-urushiol thin film took 12 h, whereas the urushiol thin film was cured within 10 min. Moreover, the strain-induced elastic buckling instability for mechanical measurements test and the bulge test confirmed that the increase in the h-urushiol content decreased the mechanical strength. Because the double bonds in the urushiol side chain contribute to forming the highly cross-linked structure, the lack of double bonds in h-urushiol resulted in the slow curing and low mechanical strength. Interestingly, the mechanical robustness started to increase over 80 mol % h-urushiol. The saturated long alkyl side chain of h-urushiol faced the surface, and the regular structure of the uniform side chain may improve the mechanical properties of the coated film. Our results will help to develop biomimetic catechol-based coatings. PMID:27076263

  14. 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.

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

    Science.gov (United States)

    Krysiak, Stefanie; Wei, Qiang; Rischka, Klaus; Hartwig, Andreas; Haag, Rainer

    2015-01-01

    Summary 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. PMID:26150898

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

    Directory of Open Access Journals (Sweden)

    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.

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

    OpenAIRE

    Janusz Czapski

    2013-01-01

    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 an...

  18. The inheritance of human erythrocyte catechol-O-methyltransferase activity

    International Nuclear Information System (INIS)

    Erythrocyte catechol-O-methyltransferase (COMT) activity was analyzed in 107 individuals from 23 families. The observed activities were consistent with an autosomal codominant inheritance of the gene coding for erythrocyte COMT activity. (author)

  19. Synthesis of catechol estrogens by human uterus and leiomyoma

    International Nuclear Information System (INIS)

    Homogenates of human endometrial, myometrial and leiomyoma tissues were incubated with (2,4,6,7-3H)-estradiol and tritiated catechol estrogens were isolated and identified. Though 2- and 4-hydroxylations were about the same in endometrium, 4-hydroxylation was two to four fold higher than 2-hydroxylation in myometrium and leiomyoma. However, endometrium showed greater capacity to form both 2- and 4-hydroxyestrogens than the other two tissues. Both 2- and 4-hydroxylations were significantly less than in myometrium. In view of the reports indicating that inhibitors of catechol 0-methyl transferase (COMT) might act as antineoplastic agents due to their interference with t-RNA methylases and since catechol estrogens inhibit COMT, the present results suggest that endogenous synthesis of catechol estrogens may play an important role in the pathophysiology of uterine leiomyoma

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

    OpenAIRE

    Alessandro Gialluisi; Serena Barbuti; Giancarlo Carli; Enrica Laura Santarcangelo

    2014-01-01

    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 ...

  1. Cytotoxic effects of catechols to glial and neuronal cells

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    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

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

    Directory of Open Access Journals (Sweden)

    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.

  3. Electron transport through catechol-functionalized molecular rods

    International Nuclear Information System (INIS)

    The charge transport properties of a catechol-type dithiol-terminated oligo-phenylene-ethynylene was investigated by cyclic voltammetry (CV) and by the scanning tunnelling microscopy break junction technique (STM-BJ). Single molecule charge transport experiments demonstrated the existence of high and low conductance regions. The junction conductance is rather weakly dependent on the redox state of the bridging molecule. However, a distinct dependence of junction formation probability and of relative stretching distances of the catechol- and quinone-type molecular junctions is observed. Substitution of the central catechol ring with alkoxy-moieties and the combination with a topological analysis of possible π-electron pathways through the respective molecular skeletons lead to a working hypothesis, which could rationalize the experimentally observed conductance characteristics of the redox-active nanojunctions

  4. Utilization of exogenous siderophores and natural catechols by Listeria monocytogenes.

    OpenAIRE

    N. Simon; Coulanges, V; ANDRE, P; Vidon, D J

    1995-01-01

    Listeria monocytogenes does not produce siderophores for iron acquisition. We demonstrate that a number of microbial siderophores and natural iron-binding compounds are able to promote the growth of iron-starved L. monocytogenes. We suggest that the ability of L. monocytogenes to use a variety of exogenous siderophores and natural catechols accounts for its ubiquitous character.

  5. An assay for human erythrocyte catechol-O-methyltransferase activity using a catechol estrogen as the substrate

    International Nuclear Information System (INIS)

    A radiometric assay for catechol-O-methyltransferase (COMT) activity in human erythrocytes is described that employs 2-hydroxy[3H]estrone, and nonradiolabeled S-adenosylmethionine (SAM) as the cosubstrates. The ease of separation of the product of the reaction, 2-methoxy[3H)estrone from 2-hydroxy-[3H]estrone makes it possible to achieve low reaction blanks. The assay is very sensitive, and only 200 μl of whole blood are used per determination. The assay is highly reproducible. The interassay variability (coefficient of variation) was 6.5% for 24 assays of COMT activity in red blood cells in blood obtained daily for 24 days from one person. In incubations conducted at 370C for 30 min, the catechol-O-methyltransferase activity was a linear function of enzyme concentration (equivalent to 11 to 180 μl of packed red blood cells). Employing this assay, we evaluated the catalytic conversion of 2-hydroxyestrone to 2-methoxy-estrone by catechol-O-methyltransferase from human red blood cells and found that the apparent Michaelis constant and the apparent maximal rate of reaction were 3 X 10-7 M and 6.7 X 10-9 mol.ml-1 erythrocytes . h-1, respectively. The catechol-O-methyltransferase activity measured in erythrocytes obtained from 100 healthy subjects (men and nonpregnant women) was 8.2 +- 0.17 (mean +- S.E.) nmol 2-methoxyestrone . ml-1 erythrocytes. h-1. (Auth.)

  6. Tyrosinase versus Catechol Oxidase: One Asparagine Makes the Difference.

    Science.gov (United States)

    Solem, Even; Tuczek, Felix; Decker, Heinz

    2016-02-18

    Tyrosinases mediate the ortho-hydroxylation and two-electron oxidation of monophenols to ortho-quinones. Catechol oxidases only catalyze the oxidation of diphenols. Although it is of significant interest, the origin of the functional discrimination between tyrosinases and catechol oxidases has been unclear. Recently, it has been postulated that a glutamate and an asparagine bind and activate a conserved water molecule towards deprotonation of monophenols. Here we demonstrate for the first time that a polyphenoloxidase, which exhibits only diphenolase activity, can be transformed to a tyrosinase by mutation to introduce an asparagine. The asparagine and a conserved glutamate are necessary to properly orient the conserved water in order to abstract a proton from the monophenol. These results provide direct evidence for the crucial importance of a proton shuttle for tyrosinase activity of type 3 copper proteins, allowing a consistent understanding of their different chemical reactivities. PMID:26773413

  7. Platinum Nanoparticles: Efficient and Stable Catechol Oxidase Mimetics.

    Science.gov (United States)

    Liu, Yi; Wu, Haohao; Chong, Yu; Wamer, Wayne G; Xia, Qingsu; Cai, Lining; Nie, Zhihong; Fu, Peter P; Yin, Jun-Jie

    2015-09-01

    Although enzyme-like nanomaterials have been extensively investigated over the past decade, most research has focused on the peroxidase-like, catalase-like, or SOD-like activity of these nanomaterials. Identifying nanomaterials having oxidase-like activities has received less attention. In this study, we demonstrate that platinum nanoparticles (Pt NPs) exhibit catechol oxidase-like activity, oxidizing polyphenols into the corresponding o-quinones. Four unique approaches are employed to demonstrate the catechol oxidase-like activity exerted by Pt NPs. First, UV-vis spectroscopy is used to monitor the oxidation of polyphenols catalyzed by Pt NPs. Second, the oxidized products of polyphenols are identified by ultrahigh-performance liquid chromatography (UHPLC) separation followed by high-resolution mass spectrometry (HRMS) identification. Third, electron spin resonance (ESR) oximetry techniques are used to confirm the O2 consumption during the oxidation reaction. Fourth, the intermediate products of semiquinone radicals formed during the oxidation of polyphenols are determined by ESR using spin stabilization. These results indicate Pt NPs possess catechol oxidase-like activity. Because polyphenols and related bioactive substances have been explored as potent antioxidants that could be useful for the prevention of cancer and cardiovascular diseases, and Pt NPs have been widely used in the chemical industry and medical science, it is essential to understand the potential effects of Pt NPs for altering or influencing the antioxidant activity of polyphenols. PMID:26305170

  8. 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.

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

    International Nuclear Information System (INIS)

    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.

  10. 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.

  11. 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...

  12. Aurone synthase is a catechol oxidase with hydroxylase activity and provides insights into the mechanism of plant polyphenol oxidases

    OpenAIRE

    Molitor, Christian; Mauracher, Stephan Gerhard; Rompel, Annette

    2016-01-01

    Catechol oxidases and tyrosinases belong to the family of polyphenol oxidases (PPOs). In contrast to tyrosinases, catechol oxidases were so far defined to lack hydroxylase activity toward monophenols. Aurone synthase (AUS1) is a plant catechol oxidase that specializes in the conversion of chalcones to aurones (flower pigments). We evidence for the first time, to our knowledge, hydroxylase activity for a catechol oxidase (AUS1) toward its natural monophenolic substrate (chalcone). The presente...

  13. 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.

  14. THE UPTAKE OF CATECHOL AMINES AT HIGH PERFUSION CONCENTRATIONS IN THE RAT ISOLATED HEART: A NOVEL CATECHOL AMINE UPTAKE PROCESS

    OpenAIRE

    Iversen, LL

    1997-01-01

    In previous studies of the uptake of catechol amines in the rat isolated heart it was shown that adrenaline and noradrenaline were accumulated by a common mechanism (Iversen, 1963, 1965). In these experiments the uptake saturated at an external amine concentration of approximately 0.2 μg/ml. noradrenaline or 0.5 μg/ml. adrenaline. However, in subsequent experiments in which hearts were perfused with (±)-adrenaline at a concentration of 5.0 μg/ml. an unexpectedly large uptake of adrenaline was...

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

    Directory of Open Access Journals (Sweden)

    Alessandro Gialluisi

    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.

  16. 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.

  17. 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 (Ead ≥-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.

  18. Erythrocuyte catechol-O-methyltransferase activity in related families with schizophrenia

    International Nuclear Information System (INIS)

    Erythrocyte catechol-O-methyltransferase (COMT) activity has been analyzed in 72 individuals from 17 related families with 18 schizophrenic members. No association with any of the three COMT genotypes could be found in this pedigree. (author)

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

    OpenAIRE

    Shuai Huang; Cui-Ping Zhang; Li, George Q.; Yue-Yi Sun; Kai Wang; Fu-Liang Hu

    2014-01-01

    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 oxid...

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

    OpenAIRE

    Muzandu, Kaampwe; El. Bohi, Khlood; Shaban, Zein; ISHIZUKA, Mayumi; KAZUSAKA, Akio; Fujita, Shoichi

    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...

  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. Sex-dependent compensated oxidative stress in the mouse liver upon deletion of catechol O-methyltransferase.

    Science.gov (United States)

    Tenorio-Laranga, Jofre; Männistö, Pekka T; Karayiorgou, Maria; Gogos, Joseph A; García-Horsman, J Arturo

    2009-05-01

    Catechol-O-methyl transferase (COMT) methylates catechols, such as L-dopa and dopamine, and COMT deficient mice show dramatic shifts in the metabolite levels of catechols. Increase in catechol metabolite levels can, in principle, lead to oxidative stress but no indices of oxidative stress have been reported in COMT-knockout (KO) mice [Forsberg MM, Juvonen RO, Helisalmi P, Leppanen J, Gogos JA, Karayiorgou M, et al. Lack of increased oxidative stress in catechol-O-methyltransferase (COMT)-deficient mice. Naunyn Schmiedebergs Arch Pharmacol 2004;370:279-89.]. Here we perform a proteomic based analysis of the livers of COMT-KO mice in search for potential compensatory mechanisms developed to cope with the effects of disrupted catechol metabolism. We found sex specific changes in proteins connected to stress response. Our results show that alterations in protein levels contribute to the homeostatic regulation in the liver of COMT deficient mice. PMID:19426692

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

    OpenAIRE

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

    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 compon...

  4. Catechol-O-methyltransferase, dopamine, and sleep-wake regulation.

    Science.gov (United States)

    Dauvilliers, Yves; Tafti, Mehdi; Landolt, Hans Peter

    2015-08-01

    Sleep and sleep disorders are complex and highly variable phenotypes regulated by many genes and environment. The catechol-O-methyltransferase (COMT) gene is an interesting candidate, being one of the major mammalian enzymes involved in the catabolism of catecholamines. The activity of COMT enzyme is genetically polymorphic due to a guanine-to-adenine transition at codon 158, resulting in a valine (Val) to methionine (Met) substitution. Individuals homozygous for the Val allele show higher COMT activity, and lower dopaminergic signaling in prefrontal cortex (PFC) than subjects homozygous for the Met allele. Since COMT has a crucial role in metabolising dopamine, it was suggested that the common functional polymorphism in the COMT gene impacts on cognitive function related to PFC, sleep-wake regulation, and potentially on sleep pathologies. The COMT Val158Met polymorphism may predict inter-individual differences in brain electroencephalography (EEG) alpha oscillations and recovery processes resulting from partial sleep loss in healthy individuals. The Val158Met polymorphism also exerts a sexual dimorphism and has a strong effect on objective daytime sleepiness in patients with narcolepsy-cataplexy. Since the COMT enzyme inactivates catecholamines, it was hypothesized that the response to stimulant drugs differs between COMT genotypes. Modafinil maintained executive functioning performance and vigilant attention throughout sleep deprivation in subjects with Val/Val genotype, but less in those with Met/Met genotype. Also, homozygous Met/Met patients with narcolepsy responded to lower doses of modafinil compared to Val/Val carriers. We review here the critical role of the common functional COMT gene polymorphism, COMT enzyme activity, and the prefrontal dopamine levels in the regulation of sleep and wakefulness in normal subjects, in narcolepsy and other sleep-related disorders, and its impact on the response to psychostimulants. PMID:25466290

  5. 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.

  6. A process optimization for bio-catalytic production of substituted catechols (3-nitrocatechol and 3-methylcatechol

    Directory of Open Access Journals (Sweden)

    Tiwary Bhupendra N

    2010-06-01

    Full Text Available Abstract Background Substituted catechols are important precursors for large-scale synthesis of pharmaceuticals and other industrial products. Most of the reported chemical synthesis methods are expensive and insufficient at industrial level. However, biological processes for production of substituted catechols could be highly selective and suitable for industrial purposes. Results We have optimized a process for bio-catalytic production of 3-substituted catechols viz. 3-nitrocatechol (3-NC and 3-methylcatechol (3-MC at pilot scale. Amongst the screened strains, two strains viz. Pseudomonas putida strain (F1 and recombinant Escherichia coli expression clone (pDTG602 harboring first two genes of toluene degradation pathway were found to accumulate 3-NC and 3-MC respectively. Various parameters such as amount of nutrients, pH, temperature, substrate concentration, aeration, inoculums size, culture volume, toxicity of substrate and product, down stream extraction, single step and two-step biotransformation were optimized at laboratory scale to obtain high yields of 3-substituted catechols. Subsequently, pilot scale studies were performed in 2.5 liter bioreactor. The rate of product accumulation at pilot scale significantly increased up to ~90-95% with time and high yields of 3-NC (10 mM and 3-MC (12 mM were obtained. Conclusion The biocatalytic production of 3-substituted catechols viz. 3-NC and 3-MC depend on some crucial parameters to obtain maximum yields of the product at pilot scale. The process optimized for production of 3-substituted catechols by using the organisms P. putida (F1 and recombinant E. coli expression clone (pDTG602 may be useful for industrial application.

  7. The effect of catechol on human peripheral blood mononuclear cells (in vitro study).

    Science.gov (United States)

    Bukowska, Bożena; Michałowicz, Jaromir; Marczak, Agnieszka

    2015-01-01

    Catechol also known as pyrocatechol or 1,2-dihydroxybenzene is formed endogenously in the organism from neurotransmitters including adrenaline, noradrenaline, and dopamine. It is also a metabolite of many drugs like DOPA, isoproterenol or aspirin and it is also formed in the environment during transformation of various xenobiotics. We evaluated in vitro the effect of catechol on the structure and function of human peripheral blood mononuclear cells (PBMCs). The cells were incubated with xenobiotic at concentration range from 2 to 500μg/mL for 1h. Human blood mononuclear cells were obtained from leucocyte-platelet buffy coat taken from healthy donors in the Blood Bank of Łódź, Poland. Using flow cytometry we have evaluated necrotic, apoptotic and morphological changes in PBMCs incubated with catechol. Moreover, we have estimated changes in reactive oxygen species (ROS) formation, protein carbonylation and lipid peroxidation in the cells studied. The compound studied provoked necrotic (from 250μg/mL), apoptotic (from 100μg/mL), and morphological changes (from 250μg/mL) in the incubated cells. We have also noted that catechol decreased H2DCF oxidation at 2 and 10μg/mL but at higher concentrations of 250 and 500μg/mL it caused statistically significant increase in the oxidation of this probe. We also observed an increase in lipid peroxidation (from 250μg/mL) and protein carbonylation (from 50μg/mL) of PBMCs. It was observed that catechol only at high concentrations was capable of inducing changes in PBMCs. The obtained results clearly showed that catechol may induce change in PBMCs only in the caste of poisoning with this compound. PMID:25528409

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

    OpenAIRE

    Sonali Sengupta; Jayanta Kumar Basu; Debarpita Ghosal

    2013-01-01

    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...

  9. Au nanoparticles and graphene quantum dots co-modified glassy carbon electrode for catechol sensing

    Science.gov (United States)

    Zhao, Xuan; He, Dawei; Wang, Yongsheng; Hu, Yin; Fu, Chen

    2016-03-01

    In this letter, the gold nanoparticles and graphene quantum dots were applied to the modification of glassy carbon electrode for the detection of catechol. The synergist cooperation between gold nanoparticles and graphene quantum dots can increase specific surface area and enhance electronic and catalytic properties of glassy carbon electrode. The detection limit of catechol is 0.869 μmol/L, demonstrating the superior detection efficiency of the gold nanoparticles and graphene quantum dots co-modified glassy carbon electrode as a new sensing platform.

  10. Regioselectivity of catechol O-methyltransferase confers enhancement of catalytic activity

    Science.gov (United States)

    Tsao, Douglas; Liu, Shubin; Dokholyan, Nikolay V.

    2011-04-01

    Catechol O-methyltransferase (COMT) metabolizes catechol moieties by methylating a single hydroxyl group at the meta- or para- hydroxyl position. Hydrophobic amino acids near the active site of COMT influence the regioselectivity of this reaction. Our sequence analysis highlights their importance by showing that these residues are highly conserved throughout evolution. Reaction barriers calculated in the gas phase reveal a lower barrier during methylation at the meta- position, suggesting that the observed meta-regioselectivity of COMT can be attributed to the substrate itself, and that COMT has evolved residues to orient the substrate in a manner that increases the rate of catalysis.

  11. Stabilities of Complexes of Scandium(III) and Yttrium(III) With Catechol Derivatives

    OpenAIRE

    Türkel, Naciye; AYDIN, Rahmiye; ÖZER, Ulviye

    1999-01-01

    The interactions of scandium(III) and yttrium(III) ions with catechol derivatives; catechol(H2L, CAT), 4-nitrocatechol(H2L, 4NCAT) and 2,3-dihydroxynaphthalene- 6-sulphonic acid(H2L, DHN) were investigated in different metal ion:ligand mole ratios, by potentiometry and spectrophotometry. The stoichiometries of formed complexes have been defined by Job's method and formation curves have been drawn for some complexes, whenever possible. The stability contants of the fourteen forme...

  12. 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

  13. 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…

  14. Catechol-O-methyltransferase gene methylation and substance use in adolescents: The TRAILS study

    NARCIS (Netherlands)

    L.J. van der Knaap (Lisette); J.M. Schäfer (Johanna); I.H.A. Franken (Ingmar); F.C. Verhulst (Frank); F.V.A. van Oort (Floor); H. Riese (Harriëtte)

    2014-01-01

    textabstractSubstance 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 Val108/158Met polymorphism modul

  15. 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.

  16. 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

  17. 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. PMID:27503417

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

    International Nuclear Information System (INIS)

    The influence of oxygen on the radiation-induced degradation of catechol (5x10-4 mol dm-3, 55 mg dm-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 (O3) and a combined EB/O3 process showed, that by EB/O3 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

  19. 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

  20. Catechol oxidation by ozone and hydroxyl radicals at the air-water interface.

    Science.gov (United States)

    Pillar, Elizabeth A; Camm, Robert C; Guzman, Marcelo I

    2014-12-16

    Anthropogenic emissions of aromatic hydrocarbons promptly react with hydroxyl radicals undergoing oxidation to form phenols and polyphenols (e.g., catechol) typically identified in the complex mixture of humic-like substances (HULIS). Because further processing of polyphenols in secondary organic aerosols (SOA) can continue mediated by a mechanism of ozonolysis at interfaces, a better understanding about how these reactions proceed at the air-water interface is needed. This work shows how catechol, a molecular probe of the oxygenated aromatic hydrocarbons present in SOA, can contribute interfacial reactive species that enhance the production of HULIS under atmospheric conditions. Reactive semiquinone radicals are quickly produced upon the encounter of 40 ppbv-6.0 ppmv O3(g) with microdroplets containing [catechol] = 1-150 μM. While the previous pathway results in the instantaneous formation of mono- and polyhydroxylated aromatic rings (PHA) and chromophoric mono- and polyhydroxylated quinones (PHQ), a different channel produces oxo- and dicarboxylic acids of low molecular weight (LMW). The cleavage of catechol occurs at the 1,2 carbon-carbon bond at the air-water interface through the formation of (1) an ozonide intermediate, (2) a hydroperoxide, and (3) cis,cis-muconic acid. However, variable [catechol] and [O3(g)] can affect the ratio of the primary products (cis,cis-muconic acid and trihydroxybenzenes) and higher order products observed (PHA, PHQ, and LMW oxo- and dicarboxylic acids). Secondary processing is confirmed by mass spectrometry, showing the production of crotonic, maleinaldehydic, maleic, glyoxylic, and oxalic acids. The proposed pathway can contribute precursors to aqueous SOA (AqSOA) formation, converting aromatic hydrocarbons into polyfunctional species widely found in tropospheric aerosols with light-absorbing brown carbon. PMID:25423038

  1. Biotransformation of phenol to hydroquinone and catechol by rat liver microsomes.

    Science.gov (United States)

    Sawahata, T; Neal, R A

    1983-03-01

    Hepatic microsomal biotransformation of phenol to hydroquinone and catechol has been investigated with special reference to the covalent binding to microsomal protein of reactive metabolites formed during microsomal metabolism of phenol. Incubation of [14C]phenol with microsomes from phenobarbital-treated rat liver in the presence of an NADPH-generating system resulted in the formation of hydroquinone and catechol in the ratio of 20:1. No significant formation of 1,2,4-benzenetriol was observed. The biotransformation of phenol to both hydroquinone and catechol required NADPH and molecular oxygen. NADH was much less effective than NADPH as an electron donor and exhibited no significant synergistic effect when used together with NADPH. The biotransformation was inhibited by typical cytochrome P-450 inhibitors such as carbon monoxide, SKF 525-A, and metyrapone. These results indicated the involvement of cytochrome P-450 in the microsomal hydroxylation of phenol at both the ortho- and para-positions. Covalent binding of radioactivity to microsomal protein was observed when [14C]phenol was incubated with rat liver microsomes in the presence of an NADPH-generating system. The covalent binding was also found to require NADPH and molecular oxygen. Inclusion of cytochrome P-450 inhibitors in the incubation mixture resulted in a decrease in the covalent binding. These results indicated that at least one step in the metabolic activation of phenol to the metabolites responsible for covalent binding to microsomal protein was mediated by cytochrome P-450. Inclusion of N-acetylcysteine in the incubation mixture resulted in the complete inhibition of the covalent binding of radioactivity derived from [14C]phenol to microsomal protein, and there was a concomitant formation of N-acetylcysteine adducts of hydroquinone and catechol. These results indicated that hydroquinone and catechol were both precursors to reactive metabolites responsible for the covalent binding. PMID:6835203

  2. 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...

  3. Effects of Active-Site Modification and Quaternary Structure on the Regioselectivity of Catechol-O-Methyltransferase.

    Science.gov (United States)

    Law, Brian J C; Bennett, Matthew R; Thompson, Mark L; Levy, Colin; Shepherd, Sarah A; Leys, David; Micklefield, Jason

    2016-02-18

    Catechol-O-methyltransferase (COMT), an important therapeutic target in the treatment of Parkinson's disease, is also being developed for biocatalytic processes, including vanillin production, although lack of regioselectivity has precluded its more widespread application. By using structural and mechanistic information, regiocomplementary COMT variants were engineered that deliver either meta- or para-methylated catechols. X-ray crystallography further revealed how the active-site residues and quaternary structure govern regioselectivity. Finally, analogues of AdoMet are accepted by the regiocomplementary COMT mutants and can be used to prepare alkylated catechols, including ethyl vanillin. PMID:26797714

  4. Surface charge-transfer complex formation of catechol on titanium(IV) oxide and the application to bio-sensing.

    Science.gov (United States)

    Murata, Yusuke; Hori, Hiroshige; Taga, Atsushi; Tada, Hiroaki

    2015-11-15

    Adsorption properties of 2-hydroxyphenol (catechol) on TiO2 particles has been studied at 298K. The adsorption proceeds from the aqueous solution with the Langmuir type behavior. Diffuse reflectance infrared spectra of the catechol-adsorbed TiO2 suggested that catechol is adsorbed on TiO2 solution via the chelation to the surface Ti ions. The adsorption induces a strong absorption in the whole visible region, of which intensity increases with an increase in the adsorption amount. Photoelectrochemical experiments and molecular orbital calculations indicate that the absorption stems from the charge-transfer (CT) transition from the HOMO of catechol to the conduction band of TiO2. Time courses for the adsorption of catechol on mesoporous TiO2 nanocrystalline film-coated glass was traced by measuring the change in the absorbance of the CT band, and analyzed on the basis of the Langmuir model. This study would present a new simple technique for sensing of important biomolecules bearing the catechol moiety. PMID:26247381

  5. Electrochemical sensing of catechol using a glassy carbon electrode modified with a composite made from silver nanoparticles, polydopamine, and graphene

    International Nuclear Information System (INIS)

    We report on the modification of a glassy carbon electrode with a composite consisting of silver nanoparticles (AgNPs), polydopamine, and graphene to give an electrochemical sensor for catechol. The composite was characterized by transmission electron microscopy, and the electrochemical behavior of catechol at the modified electrode was studied by cyclic voltammetry. The electrochemical response is greatly enhanced and thought to result from a combination of beneficial effects including the good conductivity and large surface area of the AgNPs, the high conductivity of graphene, the synergistic effects of the composite, and the increased quantity of catechol that is adsorbed on the surface of the electrode. Differential pulse voltammetric responses are proportional to the concentration of catechol between 0.5 and 240 μM levels of catechol, and the detection limit is 0.1 μM (S/N = 3). The performance of the sensor was evaluated with catechol-spiked water samples, and recoveries range from 96.5 % to 103.1 %. The results indicated that the composite presented here is a promising substrate for use in electrochemical sensing. (author)

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

    International Nuclear Information System (INIS)

    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 P21, with unit-cell parameters a = 52.77, b = 79.63, c = 61.54 Å, β = 91.14°

  7. 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°.

  8. 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.

  9. 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.

  10. Methionine sulfoxide reductase regulates brain catechol-O-methyl transferase activity

    OpenAIRE

    Moskovitz, Jackob; Walss-Bass, Consuelo; Cruz, Dianne A.; Thompson, Peter M.; Bortolato, Marco

    2014-01-01

    Catechol-O-methyl transferase (COMT) plays a key role in the degradation of brain dopamine (DA). Specifically, low COMT activity results in higher DA levels in the prefrontal cortex (PFC), thereby reducing the vulnerability for attentional and cognitive deficits in both psychotic and healthy individuals. COMT activity is markedly reduced by a non-synonymous SNP that generates a valine-to-methionine substitution on the residue 108/158, by means of as-yet incompletely understood posttranslation...

  11. 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.

  12. Identification, Characterization, and Ontogenic Study of a Catechol O-methyltransferase from Zebrafish

    OpenAIRE

    Alazizi, Adnan; Liu, Ming-Yih; Williams, Frederick E.; Kurogi, Katsuhisa; Sakakibara, Yoichi; Suiko, Masahito; Liu, Ming-Cheh

    2010-01-01

    To establish the zebrafish as a model for investigating the methylation pathway of drug metabolism, we embarked on the molecular cloning of the zebrafish catechol O-methyltransferase (COMT). By searching the GenBank database, a zebrafish nucleotide sequence encoding a putative COMT was identified. Based on the sequence information, we designed and synthesized oligonucleotides corresponding to its 5’- and 3’-coding regions of this zebrafish COMT. Using the first-strand cDNA reverse-transcribed...

  13. Computational Investigation of the Interplay of Substrate Positioning and Reactivity in Catechol O-Methyltransferase.

    Science.gov (United States)

    Patra, Niladri; Ioannidis, Efthymios I; Kulik, Heather J

    2016-01-01

    Catechol O-methyltransferase (COMT) is a SAM- and Mg2+-dependent methyltransferase that regulates neurotransmitters through methylation. Simulations and experiments have identified divergent catecholamine substrate orientations in the COMT active site: molecular dynamics simulations have favored a monodentate coordination of catecholate substrates to the active site Mg2+, and crystal structures instead preserve bidentate coordination along with short (2.65 Å) methyl donor-acceptor distances. We carry out longer dynamics (up to 350 ns) to quantify interconversion between bidentate and monodentate binding poses. We provide a systematic determination of the relative free energy of the monodentate and bidentate structures in order to identify whether structural differences alter the nature of the methyl transfer mechanism and source of enzymatic rate enhancement. We demonstrate that the bidentate and monodentate binding modes are close in energy but separated by a 7 kcal/mol free energy barrier. Analysis of interactions in the two binding modes reveals that the driving force for monodentate catecholate orientations in classical molecular dynamics simulations is derived from stronger electrostatic stabilization afforded by alternate Mg2+ coordination with strongly charged active site carboxylates. Mixed semi-empirical-classical (SQM/MM) substrate C-O distances (2.7 Å) for the bidentate case are in excellent agreement with COMT X-ray crystal structures, as long as charge transfer between the substrates, Mg2+, and surrounding ligands is permitted. SQM/MM free energy barriers for methyl transfer from bidentate and monodentate catecholate configurations are comparable at around 21-22 kcal/mol, in good agreement with experiment (18-19 kcal/mol). Overall, the work suggests that both binding poses are viable for methyl transfer, and accurate descriptions of charge transfer and electrostatics are needed to provide balanced relative barriers when multiple binding poses are

  14. Antibacterial activity of BMS-180680, a new catechol-containing monobactam.

    OpenAIRE

    Fung-Tomc, J; Bush, K; Minassian, B; Kolek, B; Flamm, R; Gradelski, E; Bonner, D

    1997-01-01

    The in vitro activities of a new catechol-containing monobactam, BMS-180680 (SQ 84,100), were compared to those of aztreonam, ceftazidime, imipenem, piperacillin-tazobactam, ciprofloxacin, amikacin, and trimethoprim-sulfamethoxazole. BMS-180680 was often the most active compound against many species of the family Enterobacteriaceae, with MICs at which 90% of the isolates were inhibited (MIC90s) of < or = 0.5 microg/ml for Escherichia coli, Klebsiella spp., Citrobacter diversus, Enterobacter a...

  15. 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.

  16. The Intracellular Pathogen Rhodococcus equi Produces a Catecholate Siderophore Required for Saprophytic Growth▿

    OpenAIRE

    Miranda-CasoLuengo, Raúl; Prescott, John F.; Vázquez-Boland, José A.; Meijer, Wim G.

    2007-01-01

    Little is known about the iron acquisition systems of the soilborne facultative intracellular pathogen Rhodococcus equi. We previously reported that expression of iupABC, encoding a putative siderophore ABC transporter system, is iron regulated and required for growth at low iron concentrations. Here we show that disruption of iupA leads to the concomitant accumulation of catecholates and a chromophore with absorption maxima at 341 and 528 nm during growth under iron-replete conditions. In co...

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

    OpenAIRE

    Deveci, Esma Ozturk; Incebiyik, Adnan; 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 he...

  18. Sensorimotor gating of schizophrenia patients depends on catechol O-methyltransferase Val158Met polymorphism

    OpenAIRE

    Quednow, B B; Wagner, M.; Mössner, R; Maier, W; Kühn, K U

    2010-01-01

    It has been recently shown that Catechol O-methyltransferase (COMT) Val(158)Met polymorphism strongly influences prepulse inhibition (PPI) of the acoustic startle response (ASR) in healthy human volunteers. Given that schizophrenia patients exhibit impairment in PPI and that COMT is a putative susceptibility gene for schizophrenia, we investigated the impact of the COMT Val(158)Met polymorphisms on PPI in schizophrenic inpatients. We analyzed COMT Val(158)Met polymorphisms and assessed startl...

  19. Genetic Contribution of Catechol-O-methyltransferase Polymorphism in Patients with Migraine without Aura

    OpenAIRE

    Park, Jeong Wook; Lee, Kwang Soo; Kim, Joong Seok; Kim, Yeong In; Shin, Hae Eun

    2007-01-01

    Background Recent genetic association studies have investigated the possible genetic role of the dopaminergic system in migraine. Catechol-O-methyltransferase (COMT) is an enzyme that plays a crucial role in the metabolism of dopamine and its genetic polymorphism is associated with three- to fourfold variation of enzymatic activity. Objectives The objective of this study was to elucidate the role of the COMT polymorphism in the genetic susceptibility to migraine and its phenotypic expression ...

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

    OpenAIRE

    Lin Gao; Hong Li; Kai Li; Zhu Shen; Ling Liu; Chunying Li; Zhengdong Zhang; Yufeng Liu

    2009-01-01

    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 oxi...

  1. Catechol-O-methyltransferase (COMT) influences the connectivity of the prefrontal cortex at rest

    OpenAIRE

    Tunbridge, Elizabeth M.; Farrell, Sarah M.; Harrison, Paul J; Mackay, Clare E

    2013-01-01

    Catechol-O-methyltransferase (COMT) modulates dopamine in the prefrontal cortex (PFC) and influences PFC dopamine-dependent cognitive task performance. A human COMT polymorphism (Val158Met) alters enzyme activity and is associated with both the activation and functional connectivity of the PFC during task performance, particularly working memory. Here, we used functional magnetic resonance imaging and a data-driven, independent components analysis (ICA) approach to compare resting state funct...

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

    OpenAIRE

    Gao, Lin; Li, Hong; Li, Kai; Shen, Zhu; Liu, Ling; Li, Chunying; Zhang, Zhengdong; Liu, Yufeng

    2009-01-01

    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 oxida...

  3. 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

  4. 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.

  5. 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.

  6. Isolation and characterization of two novel halotolerant Catechol 2, 3-dioxygenases from a halophilic bacterial consortium

    Science.gov (United States)

    Guo, Guang; Fang, Tingting; Wang, Chongyang; Huang, Yong; Tian, Fang; Cui, Qijia; Wang, Hui

    2015-12-01

    Study of enzymes in halophiles will help to understand the mechanism of aromatic hydrocarbons degradation in saline environment. In this study, two novel catechol 2,3-dioxygenases (C23O1 and C23O2) were cloned and overexpressed from a halophilic bacterial consortium enriched from an oil-contaminated saline soil. Phylogenetic analysis indicated that the novel C23Os and their relatives formed a new branch in subfamily I.2.A of extradiol dioxygenases and the sequence differences were further analyzed by amino acid sequence alignment. Two enzymes with the halotolerant feature were active over a range of 0-30% salinity and they performed more stable at high salinity than in the absence of salt. Surface electrostatic potential and amino acids composition calculation suggested high acidic residues content, accounting for their tolerance to high salinity. Moreover, two enzymes were further characterized. The enzymes activity both increased in the presence of Fe3+, Fe2+, Cu2+ and Al3+ and showed no significant inhibition by other tested metal ions. The optimal temperatures for the C23Os were 40 °C and 60 °C and their best substrates were catechol and 4-methylcatechol respectively. As the firstly isolated and characterized catechol dioxygenases from halophiles, the two halotolerant C23Os presented novel characteristics suggesting their potential application in aromatic hydrocarbons biodegradation.

  7. 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

    (VI)/catechol(amine) mixtures with plasmid DNA have been investigated to model a potential route to Cr(VI)-induced genotoxicity. Reduction of Cr(VI) by 3,4-dihydroxyphenylalanine (DOPA) (1), dopamine (2), or adrenaline (3) produces species that cause extensive DNA damage, but the products of similar reactions with catechol (4......) 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......-acetyl-Tyr with tyrosinase, respectively) were correlated with the DNA cleaving abilities of the products of these reactions. The reaction of Cr(VI) with enzymatically generated 1 produced significant amounts of H(2)O(2) and caused significant DNA damage, but the N-acetyl-DOPA did not. The extent of in vitro DNA...

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

    International Nuclear Information System (INIS)

    Highlights: ► We prepared a composite film which has bi-layers with asymmetric microstructure and relatively rich porosity which provides larger surface area for electrochemical reaction. ► The outer polysulfone layer is propitious for the organic molecules to enrich on the composite film, which brings great enhancement in electron transfer kinetics. ► 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 (ΔEp) decreases from 200 to 35 mV for hydroquinone (H2Q) 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 H2Q 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.

  9. 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.

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

    International Nuclear Information System (INIS)

    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 P212121, 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 P212121, with unit-cell parameters a = 65.5, b = 119.2, c = 158.7 Å. The crystal diffracted to 2.3 Å resolution

  11. 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

  12. 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

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

    International Nuclear Information System (INIS)

    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

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

    OpenAIRE

    G.M. Espírito Santo; A.Q. Pedro; D. Oppolzer; Bonifácio, M J; Queiroz, J. A.; Silva, F.; L.A. Passarinha

    2014-01-01

    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 it...

  15. Catechol Polymers for pH-Responsive, Targeted Drug Delivery to Cancer Cells

    OpenAIRE

    Su, Jing; Chen, Feng; Cryns, Vincent L.; Messersmith, Phillip B.

    2011-01-01

    A novel cell-targeting, pH-sensitive polymeric carrier was employed in this study for delivery of the anticancer drug bortezomib (BTZ) to cancer cells. Our strategy is based on facile conjugation of BTZ to catechol-containing polymeric carriers that are designed to be taken up selectively by cancer cells through cell surface receptor-mediated mechanisms. The polymer used as a building block in this study was poly(ethylene glycol), which was chosen for its ability to reduce nonspecific interac...

  16. Deuterium quadrupole coupling in methanol, salicyclic acid, catechol, resorcinol, and hydroquinonea)b)

    Science.gov (United States)

    Clymer, J. W.; Ragle, J. L.

    1982-11-01

    Deuteron NQR spectra of several model systems involving alcoholic of phenolic-OD groups are discussed. The spectra of alpha hydroquinone and its two isomers resorcinol and catechol show complex structure due to the presence of inequivalent O-DṡṡṡO hydrogen bonds. In the case of hydroquinone, this structure collapses to that characteristic of a single type of hydrogen bond in the beta- or clathrate-forming phase. An attempt is made to place the data in theoretical perspective by calculations of the deuterium field gradient in hydroxide ion, hydroxyl radical, methanol, and methanol dimer and by comparison with precise Hartree-Fock computations from the literature.

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

    OpenAIRE

    Omrani, Mir Davood; Bazargani, Soroush; Bagheri, Morteza; Yazdan-nejad, Hamed

    2009-01-01

    BACKGROUND: A single nucleotide variation within catechol-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 ...

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

    International Nuclear Information System (INIS)

    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)+ RNA

  19. Influence of catechol-O-methyltransferase (COMT) genotypes on the prognosis of canine mammary tumors.

    Science.gov (United States)

    Dias Pereira, P; Lopes, C C; Matos, A J F; Pinto, D; Gärtner, F; Lopes, C; Medeiros, R

    2009-11-01

    Catechol-O-methyltransferase (COMT) is an important enzyme involved in inactivation of catechol estrogens, which are metabolites with carcinogenic properties. Some investigations in human breast cancer associate a genetic polymorphism in the COMT gene (COMT val158met) with an increased risk and poor clinical progression of the disease. In dogs, there are 2 recognized single nucleotide polymorphisms in the COMT gene (COMTG216A and COMTG482A); however, their influence on the outcome of mammary neoplasms has never been investigated. The purpose of this study is to investigate the influence of COMT in the clinical progression of canine mammary tumors, namely in recurrence, metastasis and survival by testing 2 SNPs (G216A and G482A), and 2 genotypes of the COMT gene. A case series was conducted analyzing genomic DNA samples by polymerase chain reaction-restriction fragment length polymorphism from 80 bitches with mammary tumors. Animals were submitted to an active follow-up study for a period of 24 months after surgery. We observed that bitches carrying both genetic variations simultaneously are more likely to develop recurrence of mammary lesions. Our results demonstrate a possible role for COMT genotypes in the outcome of mammary neoplasms in the dog. Identifying a genetic factor predictive of recurrence may be useful in selecting the most effective surgical approach for canine mammary neoplasms. PMID:19605895

  20. 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...

  1. 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.

  2. 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; Knudsen, Gitte M; Wilson, Alan A

    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...

  3. 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)

  4. Oxidation of DNA, proteins and lipids by DOPA, protein-bound DOPA, and related catechol(amine)s

    DEFF Research Database (Denmark)

    Pattison, David I; Dean, Roger T; Davies, Michael Jonathan

    2002-01-01

    Incubation of free 3,4-dihydroxyphenylalanine (DOPA), protein-bound DOPA (PB-DOPA) and related catechols with DNA, proteins and lipids has been shown to result in oxidative damage to the target molecule. This article reviews these reactions with particular emphasis on those that occur in the...

  5. 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...

  6. RATE AND CAPACITY OF HEPATIC MICROSOMAL RING HYDROXYLATION OF PHENOL TO HYDROQUINONE AND CATECHOL IN RAINBOW TROUT (ONCORHYNCHUS MYKISS)

    Science.gov (United States)

    Rainbow trout 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 ultroviolet (UV) and elect...

  7. 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

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

    International Nuclear Information System (INIS)

    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

  9. 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.

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

    International Nuclear Information System (INIS)

    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. An electrochemically aminated glassy carbon electrode for simultaneous determination of hydroquinone and catechol.

    Science.gov (United States)

    Wang, Xiuyun; Xi, Min; Guo, Mengmeng; Sheng, Fangmeng; Xiao, Guang; Wu, Shuo; Uchiyama, Shunichi; Matsuura, Hiroaki

    2016-02-01

    In this contribution, a very simple and reliable strategy based on the easy modification of a glassy carbon electrode (GCE) by pre-electrolyzing GCE in ammonium carbamate aqueous solution was employed for the simultaneous determination of hydroquinone (HQ) and catechol (CC). Compared with bare GCE, the incorporation of nitrogen into the GCE surface structure improved the electrocatalytic properties of GCE towards the electro-oxidation of HQ and CC. The nitrogen-introduced GCE (N-GCE) was evaluated for the simultaneous detection of HQ and CC and the linear ranges for HQ and CC were both from 5 to 260 μM. Their detection limits were both evaluated to be 0.2 μM (S/N = 3). The present method was applied for the determination of HQ and CC in real river water samples with recoveries of 95.0-102.1%. In addition, a possible detection mechanism of HQ and CC was discussed. PMID:26613194

  12. 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.

  13. 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. PMID:26751827

  14. Aurone synthase is a catechol oxidase with hydroxylase activity and provides insights into the mechanism of plant polyphenol oxidases.

    Science.gov (United States)

    Molitor, Christian; Mauracher, Stephan Gerhard; Rompel, Annette

    2016-03-29

    Tyrosinases and catechol oxidases belong to the family of polyphenol oxidases (PPOs). Tyrosinases catalyze theo-hydroxylation and oxidation of phenolic compounds, whereas catechol oxidases were so far defined to lack the hydroxylation activity and catalyze solely the oxidation of o-diphenolic compounds. Aurone synthase from Coreopsis grandiflora (AUS1) is a specialized plant PPO involved in the anabolic pathway of aurones. We present, to our knowledge, the first crystal structures of a latent plant PPO, its mature active and inactive form, caused by a sulfation of a copper binding histidine. Analysis of the latent proenzyme's interface between the shielding C-terminal domain and the main core provides insights into its activation mechanisms. As AUS1 did not accept common tyrosinase substrates (tyrosine and tyramine), the enzyme is classified as a catechol oxidase. However, AUS1 showed hydroxylase activity toward its natural substrate (isoliquiritigenin), revealing that the hydroxylase activity is not correlated with the acceptance of common tyrosinase substrates. Therefore, we propose that the hydroxylase reaction is a general functionality of PPOs. Molecular dynamics simulations of docked substrate-enzyme complexes were performed, and a key residue was identified that influences the plant PPO's acceptance or rejection of tyramine. Based on the evidenced hydroxylase activity and the interactions of specific residues with the substrates during the molecular dynamics simulations, a novel catalytic reaction mechanism for plant PPOs is proposed. The presented results strongly suggest that the physiological role of plant catechol oxidases were previously underestimated, as they might hydroxylate their--so far unknown--natural substrates in vivo. PMID:26976571

  15. Epistasis between catechol-O-methyltransferase and type II metabotropic glutamate receptor 3 genes on working memory brain function

    OpenAIRE

    Tan, Hao-Yang; Chen, Qiang; Sust, Steven; Joshua W Buckholtz; Meyers, John D.; Egan, Michael F.; Mattay, Venkata S.; Meyer-Lindenberg, Andreas; Weinberger, Daniel R.; Callicott, Joseph H.

    2007-01-01

    Dopaminergic and glutamatergic systems are critical components responsible for prefrontal signal-to-noise tuning in working memory. Recent functional MRI (fMRI) studies of genetic variation in these systems in catechol-O-methyltransferase (COMT) and in metabotropic glutamate receptor mgluR3 (GRM3), respectively, suggest that these genes influence prefrontal physiological signal-to-noise in humans. Here, using fMRI, we extend these individual gene findings to examine the combined effects of CO...

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

    International Nuclear Information System (INIS)

    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-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-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

  17. Development of a poly(alizarin red S)/ionic liquid film modified electrode for voltammetric determination of catechol

    International Nuclear Information System (INIS)

    Highlights: • This study is the first to conduct electroploymerization of ARS in RTILs. • BMIMBF4 was successfully mixed in polymeric ARS film. • PARS/BMIMBF4 film was tighter, smoother and better electrochemical property. • PARS/BMIMBF4/GCE showed superior performance for catechol determination. - Abstract: A novel modified electrode for voltammetric catechol determination was fabricated by electroploymerization of alizarin red S (ARS) onto a glassy carbon electrode (GCE) in one kind of room-temperature ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate, BMIMBF4). The polymeric ARS/ionic liquid (PARS/BMIMBF4) film modified electrode was characterized by using scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and electrochemical methods. The EDX, XPS and FTIR results indicated that PARS/BMIMBF4 film was successfully obtained. Compared with the GCE modified by electroploymerization of ARS in aqueous solution, the GCE modified by electroploymerization of ARS in BMIMBF4 showed smoother and more compact morphology for coating and better electroanalytical properties. Given the combined electrochemical activity of PARS and excellent conductivity of BMIMBF4, the PARS/BMIMBF4/GCE has been successfully used for catechol determination by differential pulse voltammetry (DPV) with a linear range of 0.10 to 500 μM. The sensitivity and detection limit are 42 nA/μM and 0.026 μM, respectively. The PARS/BMIMBF4 modified electrode was successfully applied to the determination of catechol in real water samples and may serve as a simple but high-performance sensor for the determination of some environmental pollutants

  18. Affect-Modulated Startle: Interactive Influence of Catechol-O-Methyltransferase Val158Met Genotype and Childhood Trauma

    OpenAIRE

    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...

  19. Catechol O-Methyltransferase Haplotype Predicts Immediate Musculoskeletal Neck Pain and Psychological Symptoms after Motor Vehicle Collision

    OpenAIRE

    McLean, Samuel A.; Diatchenko, Luda; Lee, Young M.; Swor, Robert A.; Domeier, Robert M; Jones, Jeffrey S.; Jones, Christopher W.; Reed, Caroline; Harris, Richard E; Maixner, William; Clauw, Daniel J.; Liberzon, Israel

    2010-01-01

    Genetic variations in the catechol-o-methyltransferase (COMT) gene have been associated with experimental pain and risk of chronic pain development, but no studies have examined genetic predictors of neck pain intensity and other patient characteristics after motor vehicle collision (MVC). We evaluated the association between COMT genotype and acute neck pain intensity and other patient characteristics in 89 Caucasian individuals presenting to the emergency department (ED) after MVC. In the E...

  20. Genetic contribution of catechol-O-methyltransferase variants in treatment outcome of low back pain: a prospective genetic association study

    OpenAIRE

    Omair, Ahmad; Benedicte A Lie; Reikeras, Olav; Holden, Marit; Brox, Jens I

    2012-01-01

    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...

  1. Genetic contribution of catechol-O-methyltransferase variants in treatment outcome of low back pain: a prospective genetic association study

    OpenAIRE

    Omair Ahmad; Lie Benedicte; Reikeras Olav; Holden Marit; Brox Jens

    2012-01-01

    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 ...

  2. Genetic contribution of catechol-O-methyltransferase variants in treatment outcome of low back pain: a prospective genetic association study

    OpenAIRE

    Omair, Ahmad; Lie, Benedicte Alexandra; Reikeras, Olav; Holden, Marit; Brox, Jens Ivar

    2012-01-01

    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 w...

  3. CINETIQUE ET MECANISME DE DEGRADATION ATMOSPHERIQUE DE TROIS COMPOSES ORGANIQUES VOLATILS : L'ACETONE, LE PHENOL ET LE CATECHOL

    OpenAIRE

    TURPIN, Estelle

    2004-01-01

    M. P. Devolder Président de jury Mme C. Fittschen Directrice de thèse M. A. Mellouki Rapporteur M. E. Villenave Rapporteur M. E. Hénon Examinateur M. A. Tomas Examinateur 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 o...

  4. Association Between the Catechol-O-Methyltransferase Val158Met Polymorphism and Self-Perceived Social Acceptance in Adolescent Girls

    OpenAIRE

    Waugh, Christian E.; Dearing, Karen F.; Joormann, Jutta; GOTLIB, IAN H.

    2009-01-01

    Low perceived social acceptance is a significant risk factor for emotional difficulties in children. No studies, however, have examined genetic factors that may underlie individual differences in perceived social acceptance. In the present study we examined the relation between polymorphisms on the catechol-O-methyltransferase (COMT) Val158Met and serotonin transporter promoter (5-HTTLPR) genes and perceived social acceptance in 103 adolescent girls. Only the COMT polymorphism was related to ...

  5. Association between the Catechol-O-Methyltransferase (COMT) Val158Met Polymorphism and Manual Aiming Control in Healthy Subjects

    OpenAIRE

    Lage, Guilherme M.; Miranda, Débora M.; Romano-Silva, Marco A.; Simone B. Campos; Albuquerque, Maicon R.; Corrêa, Humberto; Leandro F. Malloy-Diniz

    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 execut...

  6. The Catechol-O-Methyltransferase (COMT) val158met Polymorphism Affects Brain Responses to Repeated Painful Stimuli

    OpenAIRE

    Marco L. Loggia; Jensen, Karin; Gollub, Randy L.; Wasan, Ajay D; Edwards, Robert R.; Kong, Jian

    2011-01-01

    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 o...

  7. Effects of the Val(158)Met catechol-O-methyltransferase gene polymorphism on olfactory processing in schizophrenia

    OpenAIRE

    Kamath, Vidyulata; Moberg, Paul J.; Gur, Raquel E.; Doty, Richard L.; Turetsky, Bruce I.

    2011-01-01

    The catechol-O-methyltransferase (COMT) val158met polymorphism has received attention in schizophrenia due to its role in prefrontal dopamine catabolism. Given the rich dopaminergic innervations of the olfactory bulb and the influence of dopamine on the transmission of olfactory signals, we examined the influence of COMT genotype status on the olfactory processing impairment observed in schizophrenia. The University of Pennsylvania Smell Identification Test was administered unirhinally to ind...

  8. Association between Catechol-O-methyltransferase rs4680 (G > A) polymorphism and lung cancer risk

    OpenAIRE

    Tan, Xiang; CHEN, MINGWU

    2014-01-01

    Background The association between the Val158Met polymorphism in the catechol-O-methyltransferase (COMT) gene and lung cancer risk remains controversial and inconclusive. Therefore, the meta-analysis was performed to provide a quality reevaluation of the association between the COMT Val158Met polymorphism and the risk of lung cancer. Methods Two major public databases (Pubmed and Embase) and several Chinese databases were searched for eligible studies. Pooled odds ratios (OR) and 95% confiden...

  9. Genetic Dissection of the Role of Catechol-O-Methyltransferase in Cognition and Stress Reactivity in Mice

    OpenAIRE

    Papaleo, Francesco; Crawley, Jacqueline N.; Song, Jian; Lipska, Barbara K.; Pickel, Jim; Weinberger, Daniel R.; Chen, Jingshan

    2008-01-01

    The COMT (catechol-O-methyltransferase) gene has been linked to a spectrum of human phenotypes, including cognition, anxiety, pain sensitivity and psychosis. Doubts about its clinical impact exist, however, because of the complexity of human COMT polymorphism and clinical variability. We generated transgenic mice overexpressing a human COMT-Val polymorphism (Val-tg), and compared them with mice containing a null COMT mutation. Increased COMT enzyme activity in Val-tg mice resulted in disrupte...

  10. Catechol O-Methyltransferase (COMT) VAL158MET Functional Polymorphism, Dental Mercury Exposure, and Self-Reported Symptoms and Mood

    OpenAIRE

    Heyer, Nicholas J.; Echeverria, Diana; Martin, Michael D.; Farin, Federico M.; Woods, James S.

    2009-01-01

    Associations were evaluated between a functional single nucleotide polymorphism (Val158Met) in the gene encoding the catecholamine catabolic enzyme catechol O-methyltransferase (COMT), dental mercury exposure, and self-reported symptoms and mood among 183 male dentists and 213 female dental assistants. Self-reported symptoms, mood, and detailed work histories were obtained by computerized questionnaire. Spot urine samples were collected and analyzed for mercury concentrations to evaluate rece...

  11. Catechol-O-Methyltransferase (COMT) Val 108/158 Met polymorphism does not modulate executive function in children with ADHD

    OpenAIRE

    Stepanian Marina; Torkaman-Zehi Adam; Deguzman Rosherie; Mbekou Valentin; Lageix Philippe; Amor Leila; Grizenko Natalie; Taerk Evan; Baron Chantal; Joober Ridha

    2004-01-01

    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 funct...

  12. Catechol-O-methyltransferase: Effects of the Val108Met polymorphism on protein turnover in human cells

    OpenAIRE

    Doyle, Anne E.; Yager, James D.

    2007-01-01

    A single nucleotide polymorphism in the human COMT (catechol-O-methyltransferase) gene has been associated with increased risk for breast cancer and several CNS diseases and disorders. The G to A polymorphism causes a valine (val) to methionine (met) substitution at codon 108 soluble- (S)/ 158 membrane- (MB) COMT, generating alleles encoding high and low activity forms of the enzyme, COMTH and COMTL, respectively. Tissues and cells with a COMTLL genotype have decreased COMT activity compared ...

  13. COMT Val158Met Genotype Determines the Direction of Cognitive Effects Produced by Catechol-O-Methyltransferase Inhibition

    OpenAIRE

    Farrell, Sarah M.; Tunbridge, Elizabeth M.; Braeutigam, Sven; Harrison, Paul J

    2012-01-01

    Background Catechol-O-methyltransferase (COMT) metabolizes dopamine. The COMT Val158Met polymorphism influences its activity, and multiple neural correlates of this genotype on dopaminergic phenotypes, especially working memory, have been reported. COMT activity can also be regulated pharmacologically by COMT inhibitors. The inverted-U relationship between cortical dopamine signaling and working memory predicts that the effects of COMT inhibition will differ according to COMT genotype. Method...

  14. 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.

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

    International Nuclear Information System (INIS)

    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 (KMapp) 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. (papers)

  16. Self-assembly of graphitic carbon nitride nanosheets–carbon nanotube composite for electrochemical simultaneous determination of catechol and hydroquinone

    International Nuclear Information System (INIS)

    Graphical abstract: Schematic diagram of hydrothermal synthesis graphitic carbon nitride nanosheets-carbon nanotube composite and theirs application for electrochemical sensing catechol and hydroquinone. - Highlights: • Self-assembly of graphitic carbon nitride nanosheets-carbon nanotube composite. • CNNS-CNT show more stronger conductivity than CNNS and CNT. • CNNS-CNT has been performed for detection of catechol and hydroquinone. • The probe was applied to detect practical samples with satisfactory results. - Abstract: In this paper, three-dimensional (3D) graphitic carbon nitride nanosheets-carbon nanotube (CNNS-CNT) composite was synthesized via hydrothermal reaction of 2D CNNS and 1D CNT-COOH by π-π stacking and electrostatic interactions. This CNNS-CNT composite was characterized by transmission electron microscope, scanning electron microscope, x-ray diffraction and fourier-transform infrared. In addition, the CNNS-CNT composite displayed excellent conductivity comparing with CNNS and CNT-COOH monomer. This composite was applied for electrochemical simultaneous determination of catechol (CC) and hydroquinone (HQ) with good sensitivity, wide linear range and low detection limit. In addition, this CNNS-CNT composite modified electrode was also applied to detect practical samples with satisfactory results

  17. 11B, 13C-NMR study of the complex formation of phenylboronate with catechol and L-dopa

    International Nuclear Information System (INIS)

    In the solution of phenylboronic acid and either catechol or L-dopa at various pH, the equilibrium between phenylboronate anion and catechol or L-dopa to form the anionic complex has been demonstrated by the existence of 11B-NMR signals for the complex and either phenylboronate anion or phenylboronic acid. By the pH dependence of the 11B-NMR chemical shift of phenylboronate-phenylboronic acid solution, the ionization constant of phenylboronic acid (pKa) has been estimated as 8.90. By the 11B-NMR spectra at pH below 7, the complex formation constant, log K, has been obtained as 4.5 for catechol, and as 4.6 for L-dopa. The 13C-NMR spectra have also demonstrated the complex formations, but in the pH 8 and 9 solution of phenylboronic acid and L-dopa, the 13C-NMR signal of carbonyl carbon of L-dopa disappeared. (author)

  18. 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.

  19. 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. PMID:27183273

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

    International Nuclear Information System (INIS)

    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

  1. Electrochemical functionalization of graphene nanosheets with catechol derivatives as an effective method for preparation of highly performance supercapacitors

    International Nuclear Information System (INIS)

    Performance enhancement of supercapacitors has been recently discussed. In this paper a novel and facile procedure for functionalization of graphene with some electroactive molecules is presented. The graphene has been functionalized by catechol-based molecules, which are electroactive molecules with electrochemically reversible properties. The functionalized graphene exhibits very effective pseudocapacitor behaviorfor charge storage. For the first time, with the aim of an electrosynthesis procedure, catechol is covalently attached on graphene sheets. This attachment has been investigated by electrochemical, X-ray photoelectron spectroscopy and attenuated total reflectance methods. Catechol molecules have been attached via formation of etheric and esteric bonds on the surface of graphene. As a result, the functionalized graphene sheets show a reversible electrochemical behavior and can be used as pseudocapacitor electrodes with an excellent stability. The electrochemical results of the prepared electrodes reveal rather high specific capacity of 288 F g−1 at a high current density of 28 A g−1, which shows remarkably enhanced performance for supercapacitor applications

  2. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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. 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

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

    Directory of Open Access Journals (Sweden)

    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.

  7. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  10. 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.

  11. Methionine sulfoxide reductase regulates brain catechol-O-methyl transferase activity.

    Science.gov (United States)

    Moskovitz, Jackob; Walss-Bass, Consuelo; Cruz, Dianne A; Thompson, Peter M; Bortolato, Marco

    2014-10-01

    Catechol-O-methyl transferase (COMT) plays a key role in the degradation of brain dopamine (DA). Specifically, low COMT activity results in higher DA levels in the prefrontal cortex (PFC), thereby reducing the vulnerability for attentional and cognitive deficits in both psychotic and healthy individuals. COMT activity is markedly reduced by a non-synonymous single-nucleotide polymorphism (SNP) that generates a valine-to-methionine substitution on the residue 108/158, by means of as-yet incompletely understood post-translational mechanisms. One post-translational modification is methionine sulfoxide, which can be reduced by the methionine sulfoxide reductase (Msr) A and B enzymes. We used recombinant COMT proteins (Val/Met108) and mice (wild-type (WT) and MsrA knockout) to determine the effect of methionine oxidation on COMT activity and COMT interaction with Msr, through a combination of enzymatic activity and Western blot assays. Recombinant COMT activity is positively regulated by MsrA, especially under oxidative conditions, whereas brains of MsrA knockout mice exhibited lower COMT activity (as compared with their WT counterparts). These results suggest that COMT activity may be reduced by methionine oxidation, and point to Msr as a key molecular determinant for the modulation of COMT activity in the brain. The role of Msr in modulating cognitive functions in healthy individuals and schizophrenia patients is yet to be determined. PMID:24735585

  12. Gender effect of catechol-O-methyltransferase Val158Met polymorphism on suicidal behavior.

    Science.gov (United States)

    Lee, Hwa-Young; Kim, Yong-Ku

    2011-01-01

    Genetic factors and catecholaminergic dysfunction have been suggested as the etiology of suicide. The catechol-O-methyltransferase (COMT) 158Val/Met polymorphism affects COMT activity; that is, the alleles encoding Val and Met are associated with relatively high and relatively low COMT activity, respectively. We aimed to identify the role of the COMT Val158Met polymorphism in suicidal attempt behavior. The COMT 158Val/Met polymorphisms were analyzed in 197 suicide attempters (male/female: 70/127), 170 control subjects (male/female: 85/85). All subjects were ethnic Korean. The Lethality Suicide Attempt Rating Scale (LSARS) and risk-rescue rating (RRR) system were explored. For the male subjects, there was a significant difference in genotype distributions and allele frequencies between control subjects and suicide attempters. That is, Val/Val genotype and Val carriers were more frequent in suicide attempters than in control subjects. For the female subjects, however, no significant difference was shown in genotype distributions and allele frequencies between control subjects and suicide attempters. There were no significant differences in LSARS and RRR according to the genotypes. The distribution of the COMT 158Val/Met polymorphism showed a biologically meaningful difference between control subjects and suicide attempters among the male subjects although selection bias should be considered. PMID:21304229

  13. Catechol-O-Methyltransferase Gene Polymorphisms in Specific Obsessive-Compulsive Disorder Patients' Subgroups.

    Science.gov (United States)

    Melo-Felippe, Fernanda Brito; de Salles Andrade, Juliana Braga; Giori, Isabele Gomes; Vieira-Fonseca, Tamiris; Fontenelle, Leonardo Franklin; Kohlrausch, Fabiana Barzotti

    2016-01-01

    Pharmacological data and animal models support the hypothesis that the dopaminergic (DA) system is implicated in obsessive-compulsive disorder (OCD). Therefore, this case-control study assessed whether genetics variations in catechol-O-methyltransferase gene (COMT) could influence susceptibility to OCD and OCD features in a Brazilian sample. A sample of 199 patients with OCD and 200 healthy individuals was genotyped for -287A > G (rs2075507) and Val158Met (rs4680) single nucleotide polymorphisms (SNPs) by TaqMan(®) or restriction mapping. We observed a statistically significant predominance of the Met low-activity allele in the male patient group as compared to the male healthy control group. The -287A > G polymorphism's genotypes and alleles were significantly overrepresented among male individuals with ordering and female subjects with washing symptoms. We also found female hoarders to exhibit a significant higher frequency of the low activity Met/Met genotype of Val158Met polymorphism compared to female patients who did not express this dimension. Our data suggest an influence of COMT polymorphisms on OCD and OCD patients' features, such as gender, and ordering, washing, and hoarding symptom dimensions. Further studies to confirm the clinical importance of COMT SNPs in OCD are warranted. PMID:26687156

  14. 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)

  15. Diversity and distribution of catechol 2, 3-dioxygenase genes in surface sediments of the Bohai Sea.

    Science.gov (United States)

    He, Peiqing; Li, Li; Liu, Jihua; Bai, Yazhi; Fang, Xisheng

    2016-05-01

    Catechol 2, 3-dioxygenase (C23O) is the key enzyme for aerobic aromatic degradation. Based on clone libraries and quantitative real-time polymerase chain reaction, we characterized diversity and distribution patterns of C23O genes in surface sediments of the Bohai Sea. The results showed that sediments of the Bohai Sea were dominated by genes related to C23O subfamily I.2.A. The samples from wastewater discharge area (DG) and aquaculture farm (KL) showed distinct composition of C23O genes when compared to the samples from Bohai Bay (BH), and total organic carbon was a crucial determinant accounted for the composition variation. C6BH12-38 and C2BH2-35 displayed the highest gene copies and highest ratios to the 16S rRNA genes in KL, and they might prefer biologically labile aromatic hydrocarbons via aquaculture inputs. Meanwhile, C7BH3-48 showed the highest gene copies and highest ratios to the 16S rRNA genes in DG, and this could be selective effect of organic loadings from wastewater discharge. An evident increase in C6BH12-38 and C7BH3-48 gene copies and reduction in diversity of C23O genes in DG and KL indicated composition perturbations of C23O genes and potential loss in functional redundancy. We suggest that ecological habitat and trophic specificity could shape the distribution of C23O genes in the Bohai Sea sediments. PMID:27190241

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

    International Nuclear Information System (INIS)

    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, [Cu2(HL)(μ-CH3COO)](ClO4), containing the ligand N,N-[bis-(2-pyridylmethyl)]-N',N'-[(2-hydroxybenzyl)(2-hydroxy-3,5-di-tert - butylbenzyl)]-1,3-propanediamine-2-ol (H3L), was synthesized and characterized by IR, 1H 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-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 10-6 to 3.27 x 10-5 mol L-1 (r = 0.9993) with a detection limit of 2.8 x 10-7 mol L-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)

  17. 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.

  18. Size-Dependent and Step-Modulated Supramolecular Electrochemical Properties of Catechol-Derived Adlayers at Pt(hkl) Surfaces

    OpenAIRE

    Rodríguez López, Margarita; Herrero, Enrique; Climent, Víctor; Rodes García, Antonio; Aldaz Riera, Antonio; Feliu, Juan M.; Carrasquillo, Arnaldo Jr.

    2013-01-01

    The electrochemical reactivity of catechol-derived adlayers is reported at platinum (Pt) single-crystal electrodes. Pt(111) and stepped vicinal surfaces are used as model surfaces possessing well-ordered nanometer-sized Pt(111) terraces ranging from 0.4 to 12 nm. The electrochemical experiments were designed to probe how the control of monatomic step-density and of atomic-level step structure can be used to modulate molecule–molecule interactions during self-assembly of aromatic-derived organ...

  19. Evidence for isofunctional enzymes in the degradation of phenol, m- and p-toluate, and p-cresol via catechol meta-cleavage pathways in Alcaligenes eutrophus.

    OpenAIRE

    Hughes, E J; Bayly, R C; Skurray, R A

    1984-01-01

    A study of the degradation of phenol, p-cresol, and m- and p-toluate by Alcaligenes eutrophus 345 has provided evidence that these compounds are metabolized via separate catechol meta-cleavage pathways. Analysis of the enzymes synthesized by wild-type and mutant strains and by strains cured of the plasmid pRA1000, which encodes m- and p-toluate degradation, indicated that two or more isofunctional enzymes mediated several steps in the pathway. The formation of three catechol 2,3-oxygenases an...

  20. The studies of FT-IR and CD spectroscopy on catechol oxidase I from tobacco

    Science.gov (United States)

    Xiao, Hourong; Xie, Yongshu; Liu, Qingliang; Xu, Xiaolong; Shi, Chunhua

    2005-10-01

    A novel copper-containing enzyme named COI (catechol oxidase I) has been isolated and purified from tobacco by extracting acetone-emerged powder with phosphate buffer, centrifugation at low temperature, ammonium sulfate fractional precipitation, and column chromatography on DEAE-sephadex (A-50), sephadex (G-75), and DEAE-celluse (DE-52). PAGE, SDS-PAGE were used to detect the enzyme purity, and to determine its molecular weight. Then the secondary structures of COI at different pH, different temperatures and different concentrations of guanidine hydrochloride (GdnHCl) were studied by the FT-IR, Fourier self-deconvolution spectra, and circular dichroism (CD). At pH 2.0, the contents of both α-helix and anti-parallel β-sheet decrease, and that of random coil increases, while β-turn is unchanged compared with the neutral condition (pH 7.0). At pH 11.0, the results indicate that the contents of α-helix, anti-parallel β-sheet and β-turn decrease, while random coil structure increases. According to the CD measurements, the relative average fractions of α-helix, anti-parallel β-sheet, β-turn/parallel β-sheet, aromatic residues and disulfide bond, and random coil/γ-turn are 41.7%, 16.7%, 23.5%, 11.3%, and 6.8% at pH 7.0, respectively, while 7.2%, 7.7%, 15.2%, 10.7%, 59.2% at pH 2.0, and 20.6%, 9.5%, 15.2%, 10.5%, 44.2% at pH 11.0. Both α-helix and random coil decrease with temperature increasing, and anti-parallel β-sheet increases at the same time. After incubated in 6 mol/L guanidine hydrochloride for 30 min, the fraction of α-helix almost disappears (only 1.1% left), while random coil/γ-turn increases to 81.8%, which coincides well with the results obtained through enzymatic activity experiment.

  1. 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.

  2. The Influence of the Amide Linkage in the Fe(III) -Binding Properties of Catechol-Modified Rosamine Derivatives.

    Science.gov (United States)

    Queirós, Carla; Leite, Andreia; G M Couto, Maria; Cunha-Silva, Luís; Barone, Giampaolo; de Castro, Baltazar; Rangel, Maria; M N Silva, André; M G Silva, Ana

    2015-10-26

    The two new fluorescent ligands RosCat1 and RosCat2 contain catechol receptors connected to rosamine platforms through an amide linkage and were synthesized by using microwave-assisted coupling reactions of carboxyl- or amine-substituted rosamines with the corresponding catechol units and subsequent deprotection. RosCat1 possesses a reverse amide, whereas RosCat2 has the usual oriented amide bond (HNCO vs. CONH, respectively). The ligands were characterized by means of NMR spectroscopy, mass-spectrometry, and DFT calculations and X-ray crystallography studies for RosCat1. The influence of the amide linkage on the photophysical properties of the fluorescent ligands was assessed in different solvents and showed a higher fluorescence quantum yield for RosCat1. The coordination chemistry of these ligands with a Fe(III) center has been rationalized by mass-spectrometric analysis and semiempirical calculations. Octahedral Fe(III) complexes were obtained by the chelation of three RosCat1 or RosCat2 ligands. Interestingly, the unconventional amide connectivity in RosCat1 imposes the formation of an eight-membered ring on the chelate complex through a "salicylate-type" mode of coordination. PMID:26493881

  3. 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

    2016-01-01

    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. PMID:27353345

  4. 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. PMID:27057995

  5. 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.

  6. Tribological properties of self-assembled monolayers of catecholic imidazolium and the spin-coated films of ionic liquids.

    Science.gov (United States)

    Liu, Jianxi; Li, Jinlong; Yu, Bo; Ma, Baodong; Zhu, Yangwen; Song, Xinwang; Cao, Xulong; Yang, Wu; Zhou, Feng

    2011-09-20

    A novel compound of an imidazolium type of ionic liquid (IL) containing a biomimetic catecholic functional group normally seen in mussel adhesive proteins was synthesized. The IL can be immobilized on a silicon surface and a variety of other engineering material surfaces via the catecholic anchor, allowing the tribological protection of these substrates for engineering applications. The surface wetting and adhesive properties and the tribological property of the synthesized self-assembled monolayers (SAMs) are successfully modulated by altering the counteranions. The chemical composition and wettability of the IL SAMs were characterized by means of X-ray photoelectron spectroscopy (XPS) and contact angle (CA) measurements. The adhesive and friction forces were measured with an atomic force microscope (AFM) on the nanometer scale. IL composite films were prepared by spin coating thin IL films on top of the SAMs. The macrotribological properties of these IL composite films were investigated with a pin-on-disk tribometer. The results indicate that the presence of IL SAMs on a surface can improve the wettability of spin-coated ionic liquids and thus the film quality and the tribological properties. These films registered a reduced friction coefficient and a significantly enhanced durability and load-carrying capacity. The tribological properties of the composite films are better than those of pure IL films because the presence of the monolayers improves the adhesion and compatibility of spin-coated IL films with substrates. PMID:21834561

  7. 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.

  8. 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

    2016-01-01

    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. PMID:27079263

  9. 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.

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

    International Nuclear Information System (INIS)

    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. - Highlights: • Catechol degradation under UV irradiation decreases in hematite-coated particles. • Free radicals are stabilized in HMT-silica system. • Semiquinone or quinine and phenol radicals were involved in HMT-silica system. • Environmentally persistent free radicals should be incorporated in organics fate modeling. - Catechol degradation was inhibited because of the formation of environmentally persistent free radicals on hematite surface

  11. 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…

  12. 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

    • Influence of chemical kinetics on postcolumn reaction in a capillary Taylor reactor with catechol analytes and photoluminescence following electron transfer.

      Science.gov (United States)

      Jung, Moon Chul; Weber, Stephen G

      2005-02-15

      Postcolumn derivatization reactions can enhance detector sensitivity and selectivity, but their successful combination with capillary liquid chromatography has been limited because of the small peak volumes in capillary chromatography. A capillary Taylor reactor (CTR), developed in our laboratory, provides simple and effective mixing and reaction in a 25-microm-radius postcolumn capillary. Homogenization of reactant streams occurs by radial diffusion, and a chemical reaction follows. Three characteristic times for a given reaction process can be predicted using simple physical and chemical parameters. Two of these times are the homogenization time, which governs how long it takes the molecules in the analyte and reagent streams to mix, and the reaction time, which governs how long the molecules in a homogeneous solution take to react. The third characteristic time is an adjustment to the reaction time called the start time, which represents an estimate of the average time the analyte stream spends without exposure to reagent. In this study, laser-induced fluorescence monitored the extent of the postcolumn reaction (reduction of Os(bpy)3(3+) by analyte to the photoluminescent Os(bpy)3(2+)) in a CTR. The reaction time depends on the reaction rates. Analysis of product versus time data yielded second-order reaction rate constants between the PFET reagent, tris(2,2'-bipyridine)osmium, and standards ((ferrocenylmethyl)trimethylammonium cation and p-hydroquinone) or catechols (dopamine, epinephrine, norepinephrine, 3, 4-dihydroxyphenylacetic acid. The extent of the reactions in a CTR were then predicted from initial reaction conditions and compared to experimental results. Both the theory and experimental results suggested the reactions of catechols were generally kinetically controlled, while those of the standards were controlled by mixing time (1-2 s). Thus, the extent of homogenization can be monitored in a CTR using the relatively fast reaction of the reagent and p

    • Interfacial electron transfer between the photoexcited porphyrin molecule and TiO2 nanoparticles: effect of catecholate binding.

      Science.gov (United States)

      Ramakrishna, G; Verma, Sandeep; Jose, D Amilan; Kumar, D Krishna; Das, Amitava; Palit, Dipak K; Ghosh, Hirendra N

      2006-05-11

      Interfacial electron transfer (ET) dynamics of 5,10,15-trisphenyl-20-(3,4-dihydroxybenzene) porphyrin (TPP-cat) adsorbed on TiO2 nanoparticles has been studied by femtosecond transient absorption spectroscopy in the visible and near-IR region exciting at 400 and 800 nm. TPP-cat molecule forms a charge transfer (CT) complex with TiO2 nanoparticles through the catechol moiety with the formation of a five-membered ring. Optical absorption measurements have shown that the Q-band of TPP-cat interacts strongly with TiO2 due to chelation; however, the Soret band is affected very little. Optical absorption measurements indicate that the catechol moiety also interacts with TiO2 nanoparticles showing the characteristic band of pure catechol-TiO2 charge transfer (CT) in the visible region. Electron injection has been confirmed by monitoring the cation radical, instant bleach, and injected electron in the conduction band of TiO2 nanoparticles. Electron injection time has been measured to be < 100 fs and recombination kinetics has been best fitted with a multiexponential function, where the majority of the injected electrons come back to the parent cation radical with a time constant of approximately 800 fs for both excitation wavelengths. However, the reaction channel for the electron injection process has been found to be different for both wavelengths. Excitation at 800 nm, found to populate the CT state of the Q-band, and from the photoexcited CT state electron injection into the conduction band, takes place through diffusion. On the other hand, with excitation at 400 nm, a complicated reaction channel takes place. Excitation with 400 nm light excites both the CT band of Cat-TiO2 and also the Soret band of TPP-cat. We have discussed the reaction path in the TPP-cat/TiO2 system after exciting with both 400 and 800 nm laser light. We have also compared ET dynamics by exciting at both wavelengths. PMID:16671709

    • Influence of endogenous S-adenosylmethionine on the determination of catechol O-methyltrausferase activity in red blood cells

      International Nuclear Information System (INIS)

      A double isotope method for the simultaneous determination of S-adenosyl-methionine (SAM) and catechol O-methyltransferase (COMT) activity in red blood cells was developed. Healthy persons contained 7.9 +- 1.9 nmol SAM per ml red blood cells and 1.9 to 3.8 nmol per ml plasma. Epinephrine increases the SAM biosynthesis rate in red blood cells. The possible influence of endogenous SAM on previous methods to determine COMT activity in red blood cells is discussed. The statement of Briggs and Briggs (Briggs, M.H. and Briggs, M. (1973) Experientia 29, 278-281) that COMT activity in red blood cells is lower during the last 3 months of pregnancy could not be verified. (Auth.)

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

      International Nuclear Information System (INIS)

      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 [18F]Ro41-0960 was synthesized by the nucleophilic aromatic substitution of [18F]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 [18F]fluoromethane ([18F]CH3F) 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)

    • 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.)

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

      International Nuclear Information System (INIS)

      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 [14C]leucine and subsequently double labeled in vivo with [3H]dopamine. After sclerotization (7 h post-ecdysis) the cuticle was extirpated, hydrolyzed and counted. An identical ratio of 14C to 3H 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 β-glucoside. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

    • 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. PMID:26563518

    • 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. 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

    OpenAIRE

    St. Łyszcz; M. Ruszkowska; U. Wojcieska; E. Zinkiewicz

    2015-01-01

    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. 3-(2-hydroxyphenyl)catechol as substrate for proximal meta ring cleavage in dibenzofuran degradation by Brevibacterium sp. strain DPO 1361.

    OpenAIRE

    Strubel, Volker; Engesser, Karl-Heinrich; Fischer, Peter; Knackmuss, Hans-Joachim

    1991-01-01

    Brevibacterium sp. strain DPO 1361 oxygenates dibenzofuran in the unusual angular position. The 3-(2-hydroxyphenyl)catechol thus generated is subject to meta ring cleavage in the proximal position, yielding 2-hydroxy-6-(2-hydroxyphenyl)-6-oxo-2,4-hexadienoic acid, which is hydrolyzed to 2-oxo-4-pentenoate and salicylate by 2-hydroxy-6-oxo-6-phenyl-2,4-hexadienoic acid hydrolase. The proximal mode of ring cleavage is definitely established by isolation and unequivocal structural characterizati...

  3. The role of catechol-O-methyltransferase (COMT) and the effects of COMT inhibition in brain and in cardiovascular and renal pathophysiology

    OpenAIRE

    Helkamaa, Teemu

    2007-01-01

    Catechol-O-methyltransferase (COMT) metabolizes catecholamines such as dopamine (DA), noradrenaline (NA) and adrenaline, which are vital neurotransmitters and hormones that play important roles in the regulation of physiological processes. COMT enzyme has a functional Val158Met polymorphism in humans, which affects the subjects COMT activity. Increasing evidence suggests that this functional polymorphism may play a role in the etiology of various diseases from schizophrenia to cancers. The ai...

  4. Association study of a functional catechol-O-methyltransferase (COMT) Val108/158Met polymorphism and suicide attempts in patients with alcohol dependence

    OpenAIRE

    Nedić, Gordana; Nikolac, Matea; Nenadić Šviglin, Korona; Muck-Šeler, Dorotea; Borovečki, Fran; Pivac, Nela

    2011-01-01

    Alcohol dependence is frequently associated with aggressive and suicidal behavior. Genetic factors contribute to both behaviors. Candidate genes, related to suicide and aggression, include genes involved in serotonin, norepinephrine and dopamine pathways. The enzyme catechol-O-methyl transferase (COMT) degrades dopamine, epinephrine and norepinephrine. The functional polymorphism (COMT Val108/158Met) affects COMT activity, with the Valine (Val) variant associated with higher and the Methionin...

  5. Differential Genetic and Epigenetic Regulation of Catechol-O-Methyl-Transferase (COMT) is Associated with Impaired Fear Inhibition in Posttraumatic Stress Disorder

    OpenAIRE

    Seth Davin Norrholm; Tanja Jovanovic; Binder, Elisabeth B.

    2013-01-01

    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 dif...

  6. A Single-Nucleotide Polymorphism in the Fetal Catechol-O-methyltransferase Gene is Associated With Spontaneous Preterm Birth in African Americans

    OpenAIRE

    Thota, Chandrasekhar; Menon, Ramkumar; Wentz, Melissa J; Fortunato, Stephen J.; Bartlett, Jackie; Drobek, Cayce O.; Nair, Sangeeta; Al-Hendy, Ayman

    2012-01-01

    Catechol-O-methyltransferase (COMT) activity has been reported to be higher in African Americans (AA) than Caucasians (Cau). COMT converts 2- and 4-hydroxy (OH) estrogens to 2- and 4-methoxyestrogens, respectively, and can increase estrogenic milieu locally in tissues. To assess whether the increased incidence of preterm birth (PTB) among AA women is associated with single-nucleotide polymorphism (SNP) in the COMT gene, we examined variations in maternal and fetal COMT genes and their associa...

  7. 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.

  8. Metrical oxidation states of 2-amidophenoxide and catecholate ligands: structural signatures of metal-ligand π bonding in potentially noninnocent ligands.

    Science.gov (United States)

    Brown, Seth N

    2012-02-01

    Catecholates and 2-amidophenoxides are prototypical "noninnocent" ligands which can form metal complexes where the ligands are best described as being in the monoanionic (imino)semiquinone or neutral (imino)quinone oxidation state instead of their closed-shell dianionic form. Through a comprehensive analysis of structural data available for compounds with these ligands in unambiguous oxidation states (109 amidophenolates, 259 catecholates), the well-known structural changes in the ligands with oxidation state can be quantified. Using these correlations, an empirical "metrical oxidation state" (MOS) which gives a continuous measure of the apparent oxidation state of the ligand can be determined based on least-squares fitting of its C-C, C-O, and C-N bond lengths to this single parameter (a simple procedure for doing so is provided via a spreadsheet in the Supporting Information). High-valent d(0) metal complexes, particularly those of vanadium(V) and molybdenum(VI), have ligands with unexpectedly positive, and generally nonintegral, MOS values. The structural effects in these complexes are attributed not to electron transfer, but rather to amidophenoxide- or catecholate-to-metal π bonding, an interpretation supported by the systematic variation of the MOS values as a function of the degree of competition with the other π-donating groups in the structures. PMID:22260321

  9. 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

    2016-06-01

    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. PMID:27148606

  10. Resolving Non-Specific and Specific Adhesive Interactions of Catechols at Solid/Liquid Interfaces at the Molecular Scale.

    Science.gov (United States)

    Utzig, Thomas; Stock, Philipp; Valtiner, Markus

    2016-08-01

    The adhesive system of mussels evolved into a powerful and adaptive system with affinity to a wide range of surfaces. It is widely known that thereby 3,4-dihydroxyphenylalanine (Dopa) plays a central role. However underlying binding energies remain unknown at the single molecular scale. Here, we use single-molecule force spectroscopy to estimate binding energies of single catechols with a large range of opposing chemical functionalities. Our data demonstrate significant interactions of Dopa with all functionalities, yet most interactions fall within the medium-strong range of 10-20 kB T. Only bidentate binding to TiO2 surfaces exhibits a higher binding energy of 29 kB T. Our data also demonstrate at the single-molecule level that oxidized Dopa and amines exhibit interaction energies in the range of covalent bonds, confirming the important role of Dopa for cross-linking in the bulk mussel adhesive. We anticipate that our approach and data will further advance the understanding of biologic and technologic adhesives. PMID:27374053

  11. BODIPY-Appended 2-(2-Pyridyl)benzimidazole Platinum(II) Catecholates for Mitochondria-Targeted Photocytotoxicity.

    Science.gov (United States)

    Mitra, Koushambi; Gautam, Srishti; Kondaiah, Paturu; Chakravarty, Akhil R

    2016-09-01

    Platinum(II) complexes of the type [Pt(L)(cat)] (1 and 2), in which H2 cat is catechol and L represents two 2-(2-pyridyl)benzimidazole ligands with 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) pendants, were synthesized to achieve mitochondria-targeted photocytotoxicity. The complexes showed strong absorptions in the range λ=510-540 nm. Complex 1 exhibited intense emission at λ=525 nm in 1 % DMSO/water solution (fluorescence quantum yield of 0.06). Nanosecond transient absorption spectral features indicated an enhanced population of the triplet excited state in di-iodinated complex 2. The generation of singlet oxygen by complex 2 upon exposure to visible light, as evidenced from experiments with 1,3-diphenylisobenzofuran, is suitable for photodynamic therapy because of the remarkable photosensitizing ability. The complexes resulted in excellent photocytotoxicity in HaCaT cells (half maximal inhibitory concentration IC50 ≈3 μm, λ=400-700 nm, light dose=10 J cm(-2) ), but they remained non-toxic in the dark (IC50 >100 μm). Confocal microscopy images of 1 and Pt estimation from isolated mitochondria showed colocalization of the complexes in the mitochondria. Complex 2 displayed generation of reactive oxygen species induced by visible light, disruption of the mitochondrial membrane potential, and apoptosis. PMID:27465792

  12. Catechol-O-methyltransferase (COMT Genotype Affects Age-Related Changes in Plasticity in Working Memory: A Pilot Study

    Directory of Open Access Journals (Sweden)

    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.

  13. Membrane-bound catechol-O-methyl transferase in cortical neurons and glial cells is intracellularly oriented

    Directory of Open Access Journals (Sweden)

    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.

  14. Self-healable mussel-mimetic nanocomposite hydrogel based on catechol-containing polyaspartamide and graphene oxide.

    Science.gov (United States)

    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. PMID:27612701

  15. Easy processing laser reduced graphene: A green and fast sensing platform for hydroquinone and catechol simultaneous determination

    International Nuclear Information System (INIS)

    Highlights: • A sensing platform for electroanalysis is constructed based on easy processing laser reduced graphene. • Our platform is highly beneficial for the construction of sensitive electrochemical sensor and biosensor. • The easy processing method probably makes it particularly attractive to produce graphene composites by premixing GO with other materials. - Abstract: A green, fast and facile approach for the preparation of graphene is proposed for constructing an electrochemical sensing platform. The fabricated platform is applied for the simultaneous determination of hydroquinone (HQ) and catechol (CC) based on laser reduced graphene (LRG) which is prepared by a consumer-grade laser pen (< $10). Scanning electron microscopy (SEM), atomic force microscope (AFM), X-ray photoelectron spectroscopy (XPS), Raman spectrum and X-ray diffraction (XRD) confirm that the synthesis of LRG could be achieved through a simple and efficient way without any chemical reducing agents and without time consuming process. The performance of LRG modified electrode shows the excellent electrocatalytic activity of LRG toward the redox reaction of HQ and CC. Under the optimized condition, the calibration curves for HQ and CC were obtained in the range of 1 to 300 μM, 2 to 300 μM, with detection limits (S/N = 3) of 0.5 μM and 0.8 μM, respectively. Therefore, our study may provide a promising sensing platform for a variety of electroanalysis applications

  16. 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.

  17. 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.

  18. Catechol-O-methyltransferase Val158Met genotype moderates the effect of disorganized attachment on social development in young children.

    Science.gov (United States)

    Hygen, Beate Wold; Guzey, Ismail Cuneyt; Belsky, Jay; Berg-Nielsen, Turid Suzanne; Wichstrøm, Lars

    2014-11-01

    Children with histories of disorganized attachment exhibit diverse problems, possibly because disorganization takes at least two distinctive forms as children age: controlling-punitive and controlling-caregiving. This variation in the developmental legacy of disorganization has been attributed primarily to variations in children's rearing experiences. Here an alternative explanation of these divergent sequelae of disorganization is evaluated: one focused on genotype. Structural equation modeling was applied to data on 704 Norwegian children to test whether the catechol-O-methyltransferase Val158Met genotype moderates the effect of disorganized attachment, which was measured dimensionally at 4 years of age using the Manchester Child Attachment Story Task, on changes in aggressive behavior and social competence from ages 4 to 6. Children who scored high on disorganization and were homozygous for the valine allele displayed significantly greater increases in aggression and decreases in self-oriented social skills (e.g., self-regulation and assertiveness) over time than did their disorganized counterparts carrying the methionine allele, whereas disorganized children carrying the methionine allele increased their other-oriented social skill (e.g., cooperation and responsibility) scores more than did valine-homozygous children. These results are consistent with the controlling-punitive and controlling-caregiving behaviors observed in disorganized children, suggesting that the children's genotype contributed to variations in the social development of disorganized children. PMID:24914507

  19. Complex multilocus effects of catechol-O-methyltransferase haplotypes predict pain and pain interference 6 weeks after motor vehicle collision

    Science.gov (United States)

    Bortsov, Andrey V.; Diatchenko, Luda; McLean, Samuel A.

    2013-01-01

    Catechol-O-methyltransferase, encoded by COMT gene, is the primary enzyme that metabolizes catecholamines. COMT haplotypes have been associated with vulnerability to persistent non-traumatic pain. In this prospective observational study, we investigated the influence of COMT on persistent pain and pain interference with life functions after motor vehicle collision (MVC) in 859 European American adults for whom overall pain (0–10 numeric rating scale) and pain interference (Brief Pain Inventory) were assessed at week 6 after MVC. Ten single nucleotide polymorphisms (SNPs) spanning the COMT gene were successfully genotyped, nine were present in three haploblocks: block 1 (rs2020917, rs737865, rs1544325), block 2 (rs4633, rs4818, rs4680, rs165774) and block 3 (rs174697, rs165599). After adjustment for multiple comparisons, haplotype TCG from block 1 predicted decreased pain interference (p =.004). The pain-protective effect of the low pain sensitivity (LPS, CGGG) haplotype from block 2 was only observed if at least one TCG haplotype was present in block 1 (haplotype × haplotype interaction p=.002 and <.0001 for pain and pain interference, respectively). Haplotype AG from block 3 was associated with pain and interference in males only (sex × haplotype interaction p=.005 and .0005, respectively). These results suggest that genetic variants in the distal promoter are important contributors to the development of persistent pain after MVC, directly and via the interaction with haplotypes in the coding region of the gene. PMID:23963787

  20. 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. PMID:27591597

  1. Catechol-O-Methyltransferase (COMT Val108/158 Met polymorphism does not modulate executive function in children with ADHD

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    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.

  2. 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.

  3. The impact of Val108/158Met polymorphism of catechol-O-methyltransferase on brain oscillations during working memory.

    Science.gov (United States)

    Altamura, Mario; Elvevåg, Brita; Goldberg, Terry E; Carver, Frederick W; Weinberger, Daniel R; Coppola, Richard

    2016-01-01

    This study investigated whether catechol-O-methyltransferase (COMT) Val/Met polymorphism was associated with variation in event-related desynchronization/synchronization (ERD/ERS) of responses during working memory (WM). 11 Val/Val and 11 Met/Met homozygous participants underwent magnetoencephalography (MEG) while performing a WM task. In contrast to small effects behaviourally, during the delay period Val/Val individuals showed lower ERS in the gamma band (Hz 30-50) in frontal regions, increased ERS in the alpha band (Hz 8-12) in the right frontal and parietal regions and increased ERD in the beta band (Hz 14-30) in the left fronto-temporal regions as compared with Met/Met homozygous individuals. During the response period Val/Val participants showed greater beta ERD in the prefrontal and parietotemporal regions. These results demonstrate that COMT genotype has a strong impact on brain responses (oscillatory activity) during WM performance likely a consequence of compensatory activity during the delay and response periods. PMID:26536074

  4. 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

    2015-11-01

    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

  5. Association between the catechol-o-methyltransferase val158met polymorphism with susceptibility and severity of carpal tunnel syndrome

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    Erkol İnal E

    2016-04-01

    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.

  6. Low-cost mussel inspired poly(catechol/polyamine) coating with superior anti-corrosion capability on copper.

    Science.gov (United States)

    Wu, Junjie; Cai, Chao; Zhou, Zhou; Qian, Hui; Zha, Fanglin; Guo, Jing; Feng, Bing; He, Tiexiang; Zhao, Ning; Xu, Jian

    2016-02-01

    A low-cost mussel inspired approach was developed to produce anti-corrosion coating on copper substrate. Catechol (CA) and polyamine (PA) were spontaneously polymerized to form adhesive coating of poly(cetechol/polyamine) (P(CA/PA)) onto copper surface and then P(CA/PA) was grafted by 1-dodecanethiol. The SEM, contact angle, XPS, FTIR and TG results demonstrated the formation of uniform, compact and thermal stable coatings through multiple interactions and chemically grafting. Electrochemical tests indicated of Cu-P(CA/PA)-SH possessed a highest corrosion potential of -81mV, a lowest corrosion current density of 0.15μA/cm(2), and a highest coating resistance of 57.19kΩcm(2), and also exhibit great long-term stability whether in solution immersion or salt spray tests. The remarkable anti-corrosion capability of Cu-P(CA/PA)-SH could be ascribed to the synergistic effect of the hydrophobicity, good stability, and strong wet adhesion of the mussel-inspired coating. This study provides an effective and cheap way for material protection and may give inspiration in the fields of material, biology and medicine relating to surface and interface engineering. PMID:26524257

  7. Effect of Plasma Pretreatments on the Bio-adhesive Functionalized by Biomimetic Catechol Groups to Human Dentin

    Science.gov (United States)

    Lee, Sangbae; Kim, Kwangmahn; Kim, Kyoungnam

    2012-10-01

    Plasma pretreatments have been introduced for modifying the surface chemistry of biomaterials. In an effort to improve the strength of the human dentin/bio-adhesive joint, oxygen plasma pretreatments to the bio-adhesive were investigated. Plasma treatments were carried out using custom-built and low pressure. Dentin were treated with plasma and used to prepare lap shear tests. Bio-adhesives were prepared synthesizing dopamine methacrylamide (DMA) monomer. DMA were copolymerized with 2-methoxyethylacrylate (MEA) by free radical polymerization. Proton nuclear magnetic resonance (^1H-NMR) and Gel permeation chromatography (GPC) analysis on samples of synthesized p(DMA-co-MEA) was performed to confirm that the resulting materials had the desired chemical structure. The effects of plasma pretreatments on surface chemistry were studied using Fourier transform infrared analysis (FTIR), and contact angle measurements. Oxygen plasma pretreatments enhanced adhesive strength by oxidizing of the catechol residue and creating a cross-linking as compared with control group. Furthermore plasma pretreatments lead to increase hydrophilicity of copolymers. Prospectively, the great potential of advanced technology in creation of the ``Plasma pretreatment to the DOPA adhesives'' would lead to the development of versatile method for coating to medial devices as well as dentin bonding.

  8. 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.

  9. Modulation of catechol estrogen synthesis by rat liver microsomes: effects of treatment with growth hormone or testosterone

    International Nuclear Information System (INIS)

    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 3H2O 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 [4-14C]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. A catechol-like phenolic ligand-functionalized hydrothermal carbon: One-pot synthesis, characterization and sorption behavior toward uranium

    International Nuclear Information System (INIS)

    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−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

  11. 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

  12. 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.

  13. Analysis of catechol-O-methyltransferase gene mutation and identification of new pathogenic gene for paroxysmal kinesigenic dyskinesia.

    Science.gov (United States)

    Gu, Chengzhi; Li, Jia; Zhu, Lianhai; Lu, Zhenhui; Huang, Huaiyu

    2016-03-01

    We aimed to analyze the mutation site and frequency of catechol-O-methyltransferase (COMT) gene, to explore the relationship between COMT genotype and phenotype, and to find new pathogenic genes for paroxysmal kinesigenic dyskinesia (PKD). PKD patients who were treated from December 2011 to January 2014 were selected and subjected to genetic testing in the exon region of COMT. Two patients and one intrafamilial healthy control were subjected to exome sequencing using whole exome capture in combination with high-throughput sequencing to find candidate pathogenic gene sites. The results were verified by Sanger sequencing. A total of 11 familial PKD patients from 4 families and 9 sporadic patients without family history were included. Pathogenic c.634dupC(p.P220fsX7) mutation of COMT gene was found in 7 familial PKD patients and3 sporadic patients. Mutated COMT gene carriers suffered from PKD earlier (average age of onset: 11.61 ± 2.33 vs 16.21 ± 2.58, P = 0.001) with symmetric symptoms in most cases, while the mutation-negative group only showed unilateral symptoms (P = 0.001). The mutation-positive group also had more daily attacks (P = 0.038). Carbamazepine worked for all mutation-positive patients (10/10, 100 %), but only for a part of mutation-negative patients (3/10, 30.0 %). About 90000 single nucleotide polymorphisms and 2000 insertion-deletion polymorphisms were detected in each of the three samples. c.737C → T(p.T246 M) mutation of POC1B gene was a new pathogenic site for a selected family. COMT gene mutation, which was the pathogenesis of most familial PKD patients and a part of sporadic patients, predicted the response to carbamazepine. POC1B may be a novel pathogenic gene for PKD. PMID:26650803

  14. Affect-modulated startle: interactive influence of catechol-O-methyltransferase Val158Met genotype and childhood trauma.

    Directory of Open Access Journals (Sweden)

    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.

  15. Complex multilocus effects of catechol-O-methyltransferase haplotypes predict pain and pain interference 6 weeks after motor vehicle collision.

    Science.gov (United States)

    Bortsov, Andrey V; Diatchenko, Luda; McLean, Samuel A

    2014-03-01

    Catechol-O-methyltransferase, encoded by COMT gene, is the primary enzyme that metabolizes catecholamines. COMT haplotypes have been associated with vulnerability to persistent non-traumatic pain. In this prospective observational study, we investigated the influence of COMT on persistent pain and pain interference with life functions after motor vehicle collision (MVC) in 859 European American adults for whom overall pain (0-10 numeric rating scale) and pain interference (Brief Pain Inventory) were assessed at week 6 after MVC. Ten single nucleotide polymorphisms spanning the COMT gene were successfully genotyped, and nine were present in three haploblocks: block 1 (rs2020917, rs737865, rs1544325), block 2 (rs4633, rs4818, rs4680, rs165774), and block 3 (rs174697, rs165599). After adjustment for multiple comparisons, haplotype TCG from block 1 predicted decreased pain interference (p = 0.004). The pain-protective effect of the low pain sensitivity (CGGG) haplotype from block 2 was only observed if at least one TCG haplotype was present in block 1 (haplotype × haplotype interaction p = 0.002 and <0.0001 for pain and pain interference, respectively). Haplotype AG from block 3 was associated with pain and interference in males only (sex × haplotype interaction p = 0.005 and 0.0005, respectively). These results suggest that genetic variants in the distal promoter are important contributors to the development of persistent pain after MVC, directly and via the interaction with haplotypes in the coding region of the gene. PMID:23963787

  16. Rate and capacity of hepatic microsomal ring-hydroxylation of phenol to hydroquinone and catechol in rainbow trout (Oncorhynchus mykiss).

    Science.gov (United States)

    Kolanczyk, Richard C; Schmieder, Patricia K

    2002-07-01

    Rainbow trout (Oncorhynchus mykiss) liver microsomes were used to study the rate of ring-hydroxylation of phenol at 11 and 25 degrees C by directly measuring the production of two potentially toxic metabolites, hydroquinone (HQ) and catechol (CAT). An HPLC method with integrated ultraviolet and electrochemical detection was used for metabolite identification and quantification at low (pmol) formation rates found in fish. The Michaelis-Menten saturation kinetics for the production of HQ and CAT over a range of phenol concentrations were determined at trout physiological pH. The apparent Km's for the production of HQ and CAT at 11 degrees C were 14+/-1 and 10+/-1 mM, respectively, with Vmax's of 552+/-71 and 161+/-15 pmol/min per mg protein. The kinetic parameters for HQ and CAT at 25 degrees C were 22+/-1 and 32+/-3 mM (Km) and 1752+/-175 and 940+/-73 pmol/min per mg protein (Vmax), respectively. The calculated increase in metabolic rate per 10 degrees C temperature rise (Q(10)) was 2.28 for HQ and 3.53 for CAT production. These experiments assess the potential for metabolic bioactivation in fish through direct quantification of putative reactive metabolites at the low, but toxicologically significant, chemical concentrations found in aquatic organisms. This work initiates a series of studies to compare activation pathway, rate, and capacity across fish species, providing a basis for development of biologically-based dose response models in diverse species. PMID:12062932

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

    International Nuclear Information System (INIS)

    Introduction: R-[11C]-SKF 82957 is a high-affinity and potent dopamine D1 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-[11C]-SKF 82957 to image the high-affinity state of the dopamine D1 receptor with PET. Methods: R-[11C]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 D1 binding of R-[11C]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 α-methyl-p-tyrosine were performed to study the specificity and sensitivity of R-[11C]-SKF 82957 dopamine D1 binding in COMT-inhibited animals. Results: Treatment with the COMT inhibitor tolcapone was associated with a dose-dependent (EC90 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-[11C]SKF 82957, from 15 (controls) to 24. Treatment with the dopamine D1 antagonist SCH 23390 reduced the striatal binding to the levels of the cerebellum, demonstrating a high specificity and selectivity of R-[11C]SKF 82957 binding. Conclusions: Pre-treatment with the COMT inhibitor tolcapone inhibits formation of an interfering metabolite of R-[11C]SKF 82957. Under such conditions, R-[11C]SKF 82957 demonstrates high potential as the first agonist radiotracer for imaging the dopamine D1 receptor by PET.

  18. 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.

  19. Electrochemical behavior of polypyrrol/AuNP composites deposited by different electrochemical methods: sensing properties towards catechol

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    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.

  20. Impaired Set-Shifting Ability in Patients with Eating Disorders, Which Is Not Moderated by Their Catechol-O-Methyltransferase Val158Met Genotype

    OpenAIRE

    Kim, Youl-Ri; Kim, Ji Eun; Kim, Mi Hyun

    2010-01-01

    The aim of this study was to examine the set-shifting ability in women with both anorexia nervosa (AN) and bulimia nervosa (BN) and to investigate whether it is contributed by the catechol-O-methyltransferase (COMT) Val158Met genotype. A total of 102 Korean participants-40 women with lifetime AN, 28 women with lifetime BN, and 34 healthy women of comparable age and intelligence quotient- were examined. A neuropsychological battery of tests was applied and blood samples were obtained for COMT ...

  1. 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.

  2. The Risk of Posttraumatic Stress Disorder After Trauma Depends on Traumatic Load and the Catechol-O-Methyltransferase Val158Met Polymorphism

    OpenAIRE

    Kolassa, Iris; Kolassa, Stephan; Ertl, Verena; Papassotiropoulos, Andreas; Quervain, Dominique J.-F. de

    2010-01-01

    BackgroundThe risk for posttraumatic stress disorder (PTSD) depends on the number of traumatic event types experienced in a dose response relationship, but genetic factors are known to also influence the risk of PTSD. The catechol-O-methyltransferase (COMT) Val158Met polymorphism has been found to affect fear extinction and might play a role in the etiology of anxiety disorders.MethodsTraumatic load and lifetime and current diagnosis of PTSD and COMT genotype were assessed in a sample of 424 ...

  3. 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

    Directory of Open Access Journals (Sweden)

    LiZhang

    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.

  4. The relationship between the val158met catechol-O-methyltransferase (COMT polymorphism and irritable bowel syndrome.

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    Pontus Karling

    Full Text Available BACKGROUND: The catechol-O-methyltransferase (COMT enzyme has a key function in the degradation of catecholamines and a functional polymorphism is val158met. The val/val genotype results in a three to fourfold higher enzymatic activity compared with the met/met genotype, with the val/met genotype exhibiting intermediate activity. Since pain syndromes as well as anxiety and depression are associated to low and high COMT activity respectively and these conditions are all associated with irritable bowel syndrome (IBS we wanted for the first time to explore the relationship between the polymorphism and IBS. METHODOLOGY/PRINCIPAL FINDINGS: 867 subjects (445 women representative of the general population and 70 consecutively sampled patients with IBS (61 women were genotyped for the val158met polymorphism and the IBS patients filled out the Hospital-Anxiety-and-Depression-Scale (HADS questionnaire, and an IBS symptom diary. RESULTS: There was a significantly higher occurrence of the val/val genotype in patients compared with controls (30% vs 20%; Chi(2 (1 3.98; p = 0.046 and a trend toward a lower occurrence of the val/met genotype in IBS patients compared with controls (39% vs 49%; Chi(2 (1 2.89; p = 0.089. Within the IBS patients the val/val carriers exhibited significantly increased bowel frequency (2.6 vs 1.8 stools per day; Chi(2 (1 5.3; p = 0.03 and a smaller proportion of stools with incomplete defecation (41% vs 68%; Chi(2 (1 4.3; p = 0.04 compared with the rest (val/met+met/met carriers. The val/val carriers also showed a trend for a smaller proportion of hard stools (0% vs 15%; Chi(2 (1 3.2; p = 0.08 and a higher frequency of postprandial defecation (26% vs 21%; Chi(2 (1 3.0; p = 0.08. CONCLUSIONS/SIGNIFICANCE: In this study we found an association between the val/val genotype of the val158met COMT gene and IBS as well as to specific IBS related bowel pattern in IBS patients.

  5. 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.

  6. 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

  7. 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.

  8. 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. PMID:26148803

  9. Effects of Temperature and pH on the Activities of Catechol 2,3-dioxygenase Obtained from Crude Oil Contaminated Soil in Ilaje, Ondo State, Nigeria.

    Science.gov (United States)

    Olukunle, O F; Babajide, O; Boboye, B

    2015-01-01

    Enrichment technique was employed for the isolation of the crude oil degrading bacteria. The isolated bacteria were screened for their degradative ability and the best degrading bacteria were selected based on their growth. Specific activities of Catechol-2,3-dioxygenase and effects of temperature and pH and their stabilities on the enzyme relative activities were observed. Bacteria isolated from the soil sample include; Bacillus cereus, B. amyloliquficiens, B. firmus, Acinetobacter calcoaceticus, Pseudomonas sp. P. fluorescens, P.putida, P.aeruginosa, Achromobacter xylosoxidans and Achromobacter sp. Screening of the degradative ability of the bacteria revealed P. aeruginosa, Bacillus cereus, Acinetobacter calcoaceticus and Achromobacter sp. to be the best degraders. The pH and temperature range with time for the enzyme activity were 6.0-8.0 and 30(o)C-50(o)C respectively. The enzyme exhibited activity that was slightly more tolerant to alkaline pH. Therefore, engineering of Catechol 2,3-dioxygenase may be employed for application on bioremediation of polluted sites. PMID:26464607

  10. Facile method for fabrication of self-supporting nanoporous gold electrodes via cyclic voltammetry in ethylene glycol, and their application to the electrooxidative determination of catechol

    International Nuclear Information System (INIS)

    A method is described for in-situ electrochemical preparation of nanoporous gold electrodes (np-GEs) via alloying and dealloying using ethylene glycol (EG) as a solvent. The np-GEs were prepared via cyclic voltammetry from a gold electrode in the presence of ZnCl2 in EG. Effects of temperature, number of scan cycles and scan rate were investigated. It is concluded that the process involves formation of interfacial elemental zinc and the formation of a gold-zinc alloy. At a temperature of 120 °C, the alloy is formed already after the first scan cycle, and ten further cycles do not cause substantial further changes in the morphology. Changes in the morphology were corroborated by data on the electroactivity of the np-GEs. The mechanism of the formation of np-GEs in EG obviously is different from that in other solvents due to the superior smoothing ability of EG for electroplating. This results in more uniform alloy layers and in a more evenly distributed porous structure. The self-supporting np-GE without any further modification displays an amperometric response to catechol (at a working voltage of 420 mV vs. SCE) in the 0.050 to 1.0 mM concentration range, with a detection limit of 1.78 μM (at an S/N of 3), indicating that the np-GE can be applied to convenient and effective determination of catechol. (author)

  11. Determination of free and conjugated catecholamines and L-3,4-dihydroxyphenylalanine in plasma and urine: evidence for a catechol-O-methyltransferase inhibitor in uraemia

    International Nuclear Information System (INIS)

    A sensitive, accurate and reproducible method has been developed for the determination of free and conjugated catecholamines and L-3,4-dihydroxyphenylalanine in plasma and urine. The assay involves the enzymatic conversion of these compounds to their radio-labelled O-methylated derivatives using catechol-O-methyltransferase and S-adenosyl-L-[methyl-3H]methionine. Recoveries of 75 +- 5% for dopamine, 70 +- 5% for adrenaline and 65 +- 5% for noradrenaline were obtained. The sensitivities were 0.5 pg for adrenaline and noradrenaline and 5-7 pg for dopamine and dihydroxyphenylalanine. Measurements of conjugated catecholamines were performed after mild acid hydrolysis for 20 min at 950 C. During this procedure no degradation of the catecholamines was observed. This assay led to the discovery of a dialyzable factor in the plasma of chronic uraemic patients which inhibits catechol-O-methyltransferase activity in vitro. The mean 22% inhibition observed for unhydrolyzed plasma increased to 42% after hydrolysis. The identity of this inhibitor which exists as an inactive conjugated form, probably a sulphate ester, and its implication in physiopathological disorders remain to be established. (Auth.)

  12. 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. PMID:21712061

  13. 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…

  14. Cytotoxicity of catechol towards human glioblastoma cells via superoxide and reactive quinones generation Citotoxicidade do catecol para células de glioblastoma humano via geração de superóxido e quinonas reativas

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    Marco Roberto Guimarães Pereira

    2004-08-01

    Full Text Available It is known that the exposure to benzene in the petroleum industry causes lympho-haematopoietic cancer among workers. However, there is little data concerning the toxicity of benzene to the central nervous system. Benzene easily penetrates the brain where it is metabolized to catechol. Since catechol autoxidizes in physiological phosphate buffer, we hypothesized that it could be toxic towards glial cells due to the generation of reactive oxygen species and quinones. In this work we studied the cytotoxic properties of catechol towards human glioblastoma cells. We found that catechol was toxic towards these cells after 72 hours and this toxicity was related to the formation of quinones. Catechol at 230µM killed 50% of cells. The catechol-induced cytotoxicity was prevented by the addition of 100U superoxide dismutase, which also inhibited the formation of quinones. These data suggest that catechol induces cytotoxicity via the extracellular generation of superoxide and quinones.Sabe-se que a exposição de trabalhadores ao benzeno na indústria petrolífera é uma causa de câncer do sistema linfo-hematopoiético. Pouco se sabe, contudo, a respeito da toxicidade do benzeno no sistema nervoso central. O benzeno penetra facilmente no cérebro, onde é metabolizado a catecol. Como o catecol se auto-oxida em tampão fosfato no pH fisiológico, supôs-se que esse composto poderia ser tóxico para células gliais por gerar espécies reativas do oxigênio e quinonas. Nesse trabalho estudou-se a citotoxicidade do catecol para células de glioblastoma humano. O catecol foi tóxico após 72 horas e essa toxicidade relacionou-se com a formação de quinonas. O catecol a 230mM matou metade das células em cultura. A toxicidade do catecol e a produção de quinonas foram inibidas por 100U de superóxido dismutase. Esses dados sugerem que a toxicidade induzida pelo catecol deve-se à produção extracelular de superóxido e quinonas reativas.

  15. Genetic polymorphisms of estrogen receptor alpha and catechol-O-methyltransferase genes in Turkish patients with familial prostate carcinoma

    Directory of Open Access Journals (Sweden)

    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

  16. Effects of garlic on cellular doubling time and DNA strand breaks caused by UV light and BPL, enhanced with catechol and TPA

    International Nuclear Information System (INIS)

    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

  17. No evidence of association between Catechol-O-Methyltransferase (COMT Val158Met genotype and performance on neuropsychological tasks in children with ADHD: A case-control study

    Directory of Open Access Journals (Sweden)

    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.

  18. Radiometric assay for phenylethanolamine N-methyltransferase and catechol O-methyltransferase in a single tissue sample: application to rat hypothalamic nuclei, pineal gland, and heart

    International Nuclear Information System (INIS)

    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-3H] 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

  19. No association between chronic musculoskeletal complaints and Val158Met polymorphism in the Catechol-O-methyltransferase gene. The HUNT study

    Directory of Open Access Journals (Sweden)

    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.

  20. 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.

  1. Interactions between genetic polymorphism of cytochrome P450-1B1, sulfotransferase 1A1, catechol-o-methyltransferase and tobacco exposure in breast cancer risk.

    Science.gov (United States)

    Saintot, Monique; Malaveille, Christian; Hautefeuille, Agnès; Gerber, Mariette

    2003-11-20

    Genetic polymorphisms of enzymes involved in the metabolism of xenobiotics and estrogens might play a role in breast carcinogenesis related to environmental exposures. In a case-only study on 282 women with breast cancer, we studied the interaction effects (ORi) between smoking habits and the gene polymorphisms of Cytochrome P450 1B1 (Val432Leu CYP1B1), Phenol-sulfotransferase 1A1 (Arg213His SULT1A1) and Catechol-O-methyltransferase (Val158Met COMT). The smokers carrying the Val CYP1B1 allele associated with a high hydroxylation activity had a higher risk of breast cancer than never smokers with the Leu/Leu genotype (ORi=2.32, 95%CI: 1.00-5.38). Also, the smokers carrying the His SULT1A1 allele associated with a low sulfation activity had a 2-fold excess risk compared to never smokers carrying Arg/Arg SULT1A1 common genotype (ORi= 2.55, 95%CI: 1.21-5.36). The His SULT1A1 allele increased the risk only in premenopausal patients. The Met COMT allele with a lower methylation activity than Val COMT did not modify the risk among smokers. The excess risk due to joint effect could result from a higher exposure to activated tobacco-compounds for women homo/heterozygous for the Val CYP1B1 allele. Also, a lower sulfation of the tobacco carcinogens among women with His SULT1A1 could increase exposure to genotoxic compounds. Alternatively, the Val CYP1B1 or His SULT1A1 allele with modified ability to metabolize estrogens could increase the level of genotoxic catechol estrogen (i.e., 4-hydroxy-estradiol) among smokers. Our study showed that gene polymorphisms of CYP1B1 and SULT1A1 induce an individual susceptibility to breast cancer among current smokers. PMID:14520706

  2. 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.

  3. Positron emission tomography in drug evaluation: Influence of three different catechol-O-methyltransferase inhibitors on metabolism of [NCA] 6-[18F]fluoro-l-dopa in Rhesus monkey

    International Nuclear Information System (INIS)

    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-[18F]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

  4. 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.

  5. Cadmium increases catechol 2,3-dioxygenase activity in Variovorax sp. 12S, a metal-tolerant and phenol-degrading strain.

    Science.gov (United States)

    Hupert-Kocurek, Katarzyna; Saczyńska, Agnieszka; Piotrowska-Seget, Zofia

    2013-11-01

    A Gram-negative bacterium, designated as strain 12S, was isolated from a heavy metal-polluted soil. According to the biochemical characteristics, FAME analysis, and 16S rRNA gene sequence analysis, the isolated strain was identified as Variovorax sp. 12S. In the presence of 0.1 mM cadmium, 12S was able to completely utilize up to 1.5 mM of phenol as the sole carbon and energy source in an MSM-TRIS medium. Degradation of phenol was accompanied by a slow bacterial growth rate and an extension of the lag phase. The cells grown on phenol showed catechol 2,3-dioxygenase (C23O) activity. The activity of C23O from 12S cultivated in medium with Cd(2+) was almost 20 % higher than in the control. Since environmental contamination with aromatic compounds is often accompanied by the presence of heavy metals, Variovorax sp. 12S and its C23O appear to be very powerful and useful tools in the biotreatment of wastewaters and soil decontamination. PMID:23934429

  6. The Simultaneous Electrochemical Detection of Catechol and Hydroquinone with [Cu(Sal-β-Ala(3,5-DMPz2]/SWCNTs/GCE

    Directory of Open Access Journals (Sweden)

    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.

  7. Iron(III) complex of N-phenylethylenediamine derivative of amine bis(phenol) ligand as model for catechol dioxygenase: Synthesis, characterization and complexation studies

    Science.gov (United States)

    Poureskandari, Maryam; Safaei, Elham; Maryam Sajjadi, S.; Karimpour, Touraj; Jaglicic, Zvonko; Lee, Yong-Ill

    2015-08-01

    A new amine bis(phenol) ligand (HLPEA), was synthesized and characterized by IR, 1H NMR spectroscopic techniques and elemental analyses. The mononuclear iron(III) complex (FeLPEA) of this ligand has been prepared and characterized by IR and UV-Vis spectroscopic techniques, ESI-MS, elemental analyses and magnetic susceptibility studies. The molecular mass of complex was determined by ESI-MS which is corresponding to a mononuclear iron(III) complex consist of amine bis(phenolate) ligand coordinated to Fe(III) including chlorine atoms and solvent molecule. The variable temperature magnetic susceptibility indicates paramagnetic character of complex. To determine the formation constant of the complex, multivariate hard modeling method was applied on spectral data collected throughout the titration of Fe(III) with ligand. FeLPEA shows good catalytic activity in cleavage oxygenation of 3,5-di-tert-butyl catechol in the presence of dioxygen at room temperature with a nearly complete conversion and particularly extradiol cleavage mechanism.

  8. Catecholate-siderophore produced by As-resistant bacterium effectively dissolved FeAsO4 and promoted Pteris vittata growth.

    Science.gov (United States)

    Liu, Xue; Yang, Guang-Mei; Guan, Dong-Xing; Ghosh, Piyasa; Ma, Lena Q

    2015-11-01

    The impact of siderophore produced by arsenic-resistant bacterium Pseudomonas PG12 on FeAsO4 dissolution and plant growth were examined. Arsenic-hyperaccumulator Pteris vittata was grown for 7 d in 0.2-strength Fe-free Hoagland solution containing FeAsO4 mineral and PG12-siderophore or fungal-siderophore desferrioxamine B (DFOB). Standard siderophore assays indicated that PG12-siderophore was catecholate-type. PG12-siderophore was more effective in promoting FeAsO4 dissolution, and Fe and As plant uptake than DFOB. Media soluble Fe and As in PG12 treatment were 34.6 and 3.07 μM, 1.6- and 1.4-fold of that in DFOB. Plant Fe content increased from 2.93 to 6.24 g kg(-1) in the roots and As content increased from 14.3 to 78.5 mg kg(-1) in the fronds. Besides, P. vittata in PG12 treatment showed 2.6-times greater biomass than DFOB. While P. vittata fronds in PG12 treatment were dominated by AsIII, those in DFOB treatment were dominated by AsV (61-77%). This study showed that siderophore-producing arsenic-resistant rhizobacteria may have potential in enhancing phytoremediation of arsenic-contaminated soils. PMID:26247380

  9. Ligand centered radical pathway in catechol oxidase activity with a trinuclear zinc-based model: Synthesis, structural characterization and luminescence properties

    Science.gov (United States)

    Pal, Sukanta; Chowdhury, Biswajit; Patra, Moumita; Maji, Milan; Biswas, Bhaskar

    2015-06-01

    A new trinuclear zinc(II) complex, [Zn3(L)(NCS)2](NO3)2·CH3OH·H2O (1), of a (N,O)-donor compartmental Schiff base ligand (H2L = N,N‧-bis(3-methoxysalicylidene)-1,3-diamino-2-propanol), has been synthesized in crystalline phase. The zinc(II) complex has been characterized by elemental analysis, IR spectroscopy, UV-Vis spectroscopy, powder X-ray diffraction study (PXRD), 1H NMR, EI mass spectrometry and thermogravimetric analysis. PXRD revealed that 1 crystallizes in P - 1 space group with a = 9.218 Å, b = 10.849 Å, c = 18.339 Å, with unit cell volume is 2179.713 (Å)3. Fluorescence spectra in methanolic solution reflect that intensity of emission for 1 is much higher compared to H2L and both the compounds exhibit good fluorescence properties. The complex 1 exhibits significant catalytic activities of biological relevance, viz. catechol oxidase. In methanol, it efficiently catalyzes the oxidation of 3,5-di-tert-butylcatechol (3,5-DTBC) to corresponding quinone via formation of a dinuclear species as [Zn2(L)(3,5-DTBC)]. Electron Paramagnetic Resonance (EPR) experiment suggests generation of radicals in the presence of 3,5-DTBC and it may be proposed that the radical pathway is probably responsible for conversion of 3,5-DTBC to 3,5-DTBQ promoted by complex of redox-innocent Zn(II) ion.

  10. Simultaneous determination of hydroquinone and catechol using a glassy carbon electrode modified with gold nanoparticles, ZnS/NiS-ZnS quantum dots and L-cysteine

    International Nuclear Information System (INIS)

    We describe an electrochemical sensor for simultaneous determination of hydroquinone (HQ) and catechol (CC). A glassy carbon electrode (GCE) was modified with gold nanoparticles, L-cysteine, and ZnS/NiS-ZnS quantum dots using a layer-by-layer technique. The materials were characterized by X-ray diffractometry, field emission scanning electron microscopy, and electrochemical impedance and Fourier transform infrared spectroscopy. Cyclic voltammetry and differential pulse voltammetry revealed this modified GCE to represent a highly sensitive sensor for the simultaneous determination of HQ and CC. The anodic peak current for HQ at a working voltage of 80 mV (vs. Ag/AgCl) is related to its concentration in the 0.1 to 300 μM range (even in the presence of 0.1 mM of CC). The anodic peak current for CC at a working voltage of 184 mV is related to its concentration in the 0.5 to 400 μM range (even in the presence of 0.1 mM of HQ). The detection limits (at an S/N ratio of 3) are 24 and 71 nM for HQ and CC, respectively. The modified GCE was successfully applied to the determination of HQ and CC in aqueous solutions and gave satisfactory results. (author)

  11. Common variants of catechol-O-methyltransferase influence patient-controlled analgesia usage and postoperative pain in patients undergoing total hysterectomy.

    Science.gov (United States)

    Tan, E-C; Lim, E C P; Ocampo, C E; Allen, J C; Sng, B-L; Sia, A T

    2016-04-01

    Catechol-O-methyltransferase (COMT) gene polymorphisms and haplotypes have been associated with both experimental and clinical pain phenotypes. In this prospective study, we investigated the association of three common polymorphisms with experimentally induced pressure pain, postoperative pain and amount of self-administered morphine in 973 patients who underwent scheduled total hysterectomy. DNA extracted from peripheral blood was genotyped for three COMT polymorphisms by Taqman assay or a PCR-based method. In the overall sample, rs4633 and rs4680 were significantly associated with morphine use, whereas rs4818 was associated with time-averaged pain scores. Statistically significant associations were found between COMT rs4633 and rs4680 genotypes and the amount of morphine self-administered through a patient-controlled analgesia pump. For rs4818, the only statistically significant association was with time-averaged pain scores. Haplotype analysis showed statistically significant association of the low pain sensitivity haplotype with time-averaged pain scores; and average pain sensitivity haplotype with total morphine and weight-adjusted morphine. PMID:25963335

  12. 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. PMID:27163503

  13. Determination of catechol-O-methyltransferase activity in brain tissue by high-performance liquid chromatography with on-line radiochemical detection

    International Nuclear Information System (INIS)

    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 3H- labeled 3-O- and 4-O-methylated products of the substrate, 3,4- dihydroxybenzoic acid, using S-adenosyl-L-[methyl-3H]methionine as the methyl donor, or the measurement of 14C-labeled 3-O- and 4-O-methylated products of the substrate, [7-14C]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 3H-labeled product, and 0. 04 pmol 14C-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

  14. 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.

  15. Identification of Potential Off-target Toxicity Liabilities of Catechol-O-methyltransferase Inhibitors by Differential Competition Capture Compound Mass Spectrometry.

    Science.gov (United States)

    von Kleist, Lisa; Michaelis, Simon; Bartho, Kathrin; Graebner, Olivia; Schlief, Marén; Dreger, Mathias; Schrey, Anna K; Sefkow, Michael; Kroll, Friedrich; Koester, Hubert; Luo, Yan

    2016-05-26

    Structurally related inhibitors of a shared therapeutic target may differ regarding potential toxicity issues that are caused by different off-target bindings. We devised a differential competition capture compound mass spectrometry (dCCMS) strategy to effectively differentiate off-target profiles. Tolcapone and entacapone are potent inhibitors of catechol-O-methyl transferase (COMT) for the treatment of Parkinson's disease. Tolcapone is also known for its hepatotoxic side effects even though it is therapeutically more potent than entacapone. Here, we identified 3-hydroxyisobutyryl-CoA hydrolase (HIBCH) as a possible toxicity-causing off-target of tolcapone, and this protein is not bound by the less toxic COMT inhibitor entacapone. Moreover, two novel compounds from a focused library synthesized in-house, N(2),N(2),N(3),N(3)-tetraethyl-6,7-dihydroxy-5-nitronaphthalene-2,3-dicarboxamide and 5-(3,4-dihydroxy-5-nitrobenzylidene)-3-ethylthiazolidine-2,4-dione, were utilized to gain insight into the structure-activity relationships in binding to COMT and the novel off-target HIBCH. These compounds, especially N(2),N(2),N(3),N(3)-tetraethyl-6,7-dihydroxy-5-nitronaphthalene-2,3-dicarboxamide, could serve as starting point for the development of improved and more specific COMT inhibitors. PMID:27074629

  16. 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.

  17. 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.

  18. Association between the Catechol-O-Methyltransferase (COMT) Val158Met Polymorphism and Alexithymia in Patients with Obsessive-Compulsive Disorder

    Science.gov (United States)

    Koh, Min Jung; Kang, Jee In; Namkoong, Kee; Lee, Su Young

    2016-01-01

    Purpose Alexithymia, defined as a deficit in the ability to recognize and describe one's own feelings, may be related to the development and maintenance of obsessive-compulsive symptoms. The aim of this study was to evaluate the association between the catechol-O-methyltransferase (COMT) Val158Met polymorphism and alexithymia in patients with obsessive-compulsive disorder (OCD). Materials and Methods We recruited 244 patients with OCD (169 males, 75 females). Alexithymia was assessed using the 20-item Toronto Alexithymia Scale (TAS-20), and genotyping of the COMT Val158Met polymorphism was evaluated. Results Patients with the COMT Val/Val genotype had significantly higher total and "difficulty identifying feelings" (DIF) subdimension scores than those with the Val/Met or Met/Met genotypes. Patients with the COMT Val/Val genotype had significantly higher "difficulty describing feelings" (DDF) subdimension scores than those with the COMT Val/Met genotype. However, there were no differences in the scores for the "externally oriented thinking" (EOT) subdimension among the three genotypes. Conclusion These results indicate that the high-activity Val allele of the COMT Val158Met polymorphism is associated with increased alexithymic traits in patients with OCD. The present finding suggests that alexithymia is an endophenotype of OCD that is mediated by the COMT Val158Met polymorphism. PMID:26996573

  19. The impact of the Catechol-O-methyltransferase Val158Met polymorphism on survival in the general population – the HUNT study

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    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.

  20. Study on the application of reduced graphene oxide and multiwall carbon nanotubes hybrid materials for simultaneous determination of catechol, hydroquinone, p-cresol and nitrite

    International Nuclear Information System (INIS)

    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 N2 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 (NO2−) 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 NO2−. 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: ► The novel RGO–MWNTs hybrid materials were synthesized. ► The simultaneous detection of four environmental contaminations was achieved. ► 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 N2 sorption–desorption isotherms. Due to the excellent catalytic activity, enhanced electrical conductivity and high surface area of the RGO–MWNTs, the simultaneous measurement of hydroquinone

  1. 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

  2. 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

  3. Departure from multiplicative interaction for catechol-O-methyltransferase genotype and active/passive exposure to tobacco smoke among women with breast cancer

    Directory of Open Access Journals (Sweden)

    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.

  4. 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. PMID:26724569

  5. 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. PMID:25339109

  6. 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.

  7. 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.

  8. 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.

  9. 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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    TimothyDurazzo

    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

  10. Effect of Catechol-O-methyltransferase-gene (COMT) Variants on Experimental and Acute Postoperative Pain in 1,000 Women undergoing Surgery for Breast Cancer

    Science.gov (United States)

    Kambur, Oleg; Kaunisto, Mari A.; Tikkanen, Emmi; Leal, Suzanne M.; Ripatti, Samuli; Kalso, Eija A.

    2016-01-01

    Background Catechol-O-methyltransferase (COMT) metabolizes catecholamines in different tissues. Polymorphisms in COMT gene can attenuate COMT activity and increase sensitivity to pain. Human studies exploring the effect of COMT polymorphisms on pain sensitivity have mostly included small, heterogeneous samples and have ignored several important single nucleotide polymorphisms (SNPs). This study examines the effect of COMT polymorphisms on experimental and postoperative pain phenotypes in a large ethnically homogeneous female patient cohort. Methods Intensity of cold (+2–4°C) and heat (+48°C) pain and tolerance to cold pain were assessed in 1,000 patients scheduled for breast cancer surgery. Acute postoperative pain and oxycodone requirements were recorded. Twenty-two COMT SNPs were genotyped and their association with six pain phenotypes analyzed with linear regression. Results There was no association between any of the tested pain phenotypes and SNP rs4680. The strongest association signals were seen between rs165774 and heat pain intensity as well as rs887200 and cold pain intensity. In both cases, minor allele carriers reported less pain. Neither of these results remained significant after strict multiple testing corrections. When analyzed further, the effect of rs887200 was, however, shown to be significant and consistent throughout the cold pressure test. No evidence of association between the SNPs and postoperative oxycodone consumption was found. Conclusions SNPs rs887200 and rs165774 located in the untranslated regions of the gene had the strongest effects on pain sensitivity. Their effect on pain is described here for the first time. These results should be confirmed in further studies and the potential functional mechanisms of the variants studied. PMID:24343288

  11. The laccase-catalyzed domino reaction between catechols and heterocyclic 1,3-dicarbonyls and the unambiguous structure elucidation of the products by NMR spectroscopy and X-ray crystal structure analysis.

    Science.gov (United States)

    Hajdok, Szilvia; Conrad, Jürgen; Leutbecher, Heiko; Strobel, Sabine; Schleid, Thomas; Beifuss, Uwe

    2009-10-01

    The laccase-catalyzed reaction between catechols and heterocyclic 1,3-dicarbonyls (pyridinones, quinolinones, thiocoumarins) using aerial oxygen as the oxidant delivers benzofuropyridinones, benzofuroquinolinones, and thiocoumestans in a simple fashion, highly regioselectively with yields ranging from 55 to 98%. With barbituric acid derivatives the exclusive formation of dispiropyrimidinone derivatives takes place. The unambiguous and complete structure elucidation of all reaction products has been achieved by means of NMR spectroscopic methods (HSQMBC and band-selective HMBC) as well as by X-ray crystal structure analysis. PMID:19739645

  12. Influence of variation in the catechol-O-methyltransferase gene on the clinical outcome after lumbar spine surgery for one-level symptomatic disc disease: a report on 176 cases

    OpenAIRE

    Rut, Marcin; Machoy-Mokrzyńska, Anna; Ręcławowicz, Daniel; Słoniewski, Paweł; Kurzawski, Mateusz; Droździk, Marek; Safranow, Krzysztof; Morawska, Michalina; Białecka, Monika

    2013-01-01

    Background This study was aimed at the evaluation of the relationship between genetic polymorphisms of catechol-O-methyltransferase (COMT) (rs4680:A > G—Val158Met, rs6269:A > G, rs4633:C > T, rs4818:C > G) and pain sensitivity after lumbar discectomy. Methods All patients had one-level symptomatic disc herniation from L3 to S1. The primary data recorded included visual analogue pain scales assessing back and leg pain, Oswestry Disability Questionnaire assessing quality of life and pain intens...

  13. 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.

  14. Determination of the characteristics and transformations in a mull medium of a humic model derived from auto-oxidation of the catechol-glycine system and selectively labelled with carbon-14

    International Nuclear Information System (INIS)

    Brown nitrogen-containing polymers are prepared by auto-oxidation at pH 7.9 from an equimolar mixture of catechol and glycine. Strict control of the experimental conditions yields products of constant composition, and affords a basis for the selective preparation of three polymers labelled with 14C on the atoms C1 and C2 of the glycine and on the catechol ring. These polymers have a mean molecular size smaller than that of humic acids extracted from neutral soils but their structure resembles more that of hydrolytic residues from eutrophic humic acids and melanins. Their stoichiometric ratio is 2 moles of glycine to 7 moles of catechol. They are not completely homogeneous and contain two groups of substances: the first and more abundant group is larger and permits optimum stabilization of the glycine in highly resonant structures; the second group remains more sensitive to hydrolytic treatment and biodegradation; they are characterized by partial fission of the aromatic rings during synthesis, which is responsible for the formation of the ring-deriving-COOH groups. The biodegradation of these polymers in a neutral mull reveals two successive stages: (a) an initial stage lasting five days, during which the ring-deriving-COOH groups are actively decarboxylated, whereas the glycine bound to the less stable fraction is degraded perferentially and then metabolized in the unextractable microbial substances (microbial humin). The non-amino residues of the polymers then have a depressant effect on soil respiration, which disappears only when their transformation by degradation or reaction with the soil organic compounds occurs; (b) A second stage, characterized by very slow mineralization and affecting almost exclusively the more stable polymers incorporated into the humin by physico-chemical insolubilization. There is then no further preferential degradiation of the glycine, the stability of which equals that of the ring-deriving carbon compounds of aromatic origin. The

  15. 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.

  16. Effect of ring-fluorination on the rate of O-methylation of dihydroxyphenylalanine (DOPA) by catechol-O-methyltransferase: significance in the development of 18F-PETT scanning agents

    International Nuclear Information System (INIS)

    The three ring-fluorinated analogs of dihydroxyphenylalanine (DOPA) were synthesized and the kinetics of their O-methylation catalyzed by catechol-O-methyltransferase (comt) compared to those of DOPA. The affinities (Km) of 2-FDOPA, 5-FDOPA, DOPA, and 6-FDOPA were 20, 23, 55, and 552 microM, respectively, whilst the Vmax values were 4.0, 4.4, 5.0 and 5.4 nmol per min per mg protein. The importance of the low affinity and decreased rate constant of 6-FDOPA for COMT are discussed with regard to the use of 6-FDOPA as an 18-fluorine labeled probe for positron emission transaxial tomography (PETT)

  17. 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

    International Nuclear Information System (INIS)

    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 bonding, and dipole-dipole interactions between the three isomers and water. Catechol was found to have the strongest hydrophilic and the weakest hydrophobic interactions with water among the three isomers.

  18. 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 bonding, and dipole-dipole interactions between the three isomers and water. Catechol was found to have the strongest hydrophilic and the weakest hydrophobic interactions with water among the three isomers.

  19. Catechol-O-methyltransferase Val158Met genotype and the clinical responses to duloxetine treatment or plasma levels of 3-methoxy-4-hydroxyphenylglycol and homovanillic acid in Japanese patients with major depressive disorder

    Directory of Open Access Journals (Sweden)

    Atake K

    2015-04-01

    Full Text Available Kiyokazu Atake, Reiji Yoshimura, Hikaru Hori, Asuka Katsuki, Jun Nakamura Department of Psychiatry, University of Occupational and Environmental Health, Kitakyushu, Fukuoka, Japan Purpose: This study investigated the relationships among the plasma levels of catecholamine metabolites, the clinical response to duloxetine treatment, and Val158Met polymorphism of the catechol-O-methyltransferase (COMT gene. Subjects and methods: Sixty-four patients and 30 healthy control subjects were recruited. Major depressive episodes were diagnosed using the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision criteria. The severity of depression was evaluated using the 17-item Hamilton Rating Scale for Depression (HAMD17. Patients whose HAMD17 scores were 15 or greater were enrolled in the study. Blood sampling and clinical evaluation were performed at week 0 and week 8. The levels of plasma catecholamine metabolites were measured using high-performance liquid chromatography with electrochemical detection. Genotyping was performed using direct sequencing. Results: Thirty of 45 patients (67% responded to duloxetine treatment during the 8 weeks of treatment. The baseline plasma levels of 3-methoxy-4-hydroxyphenylglycol (MHPG, but not homovanillic acid (HVA, were lower in patients with major depressive disorder (MDD who had the Val/Val genotype than in patients who were Met-carriers. Patients with MDD and the Val/Val genotype, but not Met carriers, had increased plasma levels of MHPG after 8 weeks of duloxetine treatment. The baseline plasma MHPG levels in healthy control subjects with the Val/Val genotype were significantly higher than those in patients with MDD. Among the subjects in the MDD group with the Val/Val genotype, the plasma MHPG levels increased to the same degree as in the healthy control subjects with the Val/Val genotype after 8 weeks of duloxetine treatment. Conclusion: The

  20. Microdialysis with radiometric monitoring of L-[β-11C]DOPA to assess dopaminergic metabolism: effect of inhibitors of L-amino acid decarboxylase, monoamine oxidase, and catechol-O-methyltransferase on rat striatal dialysate.

    Science.gov (United States)

    Okada, Maki; Nakao, Ryuji; Hosoi, Rie; Zhang, Ming-Rong; Fukumura, Toshimitsu; Suzuki, Kazutoshi; Inoue, Osamu

    2011-01-01

    The catecholamine, dopamine (DA), is synthesized from 3,4-dihydroxy-L-phenylalanine (L-DOPA) by aromatic L-amino acid decarboxylase (AADC). Dopamine metabolism is regulated by monoamine oxidase (MAO) and catechol-O-methyltransferase (COMT). To measure dopaminergic metabolism, we used microdialysis with radiometric detection to monitor L-[β-(11)C]DOPA metabolites in the extracellular space of the rat striatum. We also evaluated the effects of AADC, MAO, and COMT inhibitors on metabolite profiles. The major early species measured after administration of L-[β-(11)C]DOPA were [(11)C]3,4-dihydroxyphenylacetic acid ([(11)C]DOPAC) and [(11)C]homovanillic acid ([(11)C]HVA) in a 1:1 ratio, which shifted toward [(11)C]HVA with time. An AADC inhibitor increased the uptake of L-[β-(11)C]DOPA and L-3-O-methyl-[(11)C]DOPA and delayed the accumulation of [(11)C]DOPAC and [(11)C]HVA. The MAO and COMT inhibitors increased the production of [(11)C]3-methoxytyramine and [(11)C]DOPAC, respectively. These results reflect the L-DOPA metabolic pathway, suggesting that this method may be useful for assessing dopaminergic metabolism. PMID:20407462

  1. Monoamine Oxidase A (MAOA) and Catechol-O-Methyltransferase (COMT) Gene Polymorphisms Interact with Maternal Parenting in Association with Adolescent Reactive Aggression but not Proactive Aggression: Evidence of Differential Susceptibility.

    Science.gov (United States)

    Zhang, Wenxin; Cao, Cong; Wang, Meiping; Ji, Linqin; Cao, Yanmiao

    2016-04-01

    To date, whether and how gene-environment (G × E) interactions operate differently across distinct subtypes of aggression remains untested. More recently, in contrast with the diathesis-stress hypothesis, an alternative hypothesis of differential susceptibility proposes that individuals could be differentially susceptible to environments depending on their genotypes in a "for better and for worse" manner. The current study examined interactions between monoamine oxidase A (MAOA) T941G and catechol-O-methyltransferase (COMT) Val158Met polymorphisms with maternal parenting on two types of aggression: reactive and proactive. Moreover, whether these potential G × E interactions would be consistent with the diathesis-stress versus the differential susceptibility hypothesis was tested. Within the sample of 1399 Chinese Han adolescents (47.2 % girls, M age = 12.32 years, SD = 0.50), MAOA and COMT genes both interacted with positive parenting in their associations with reactive but not proactive aggression. Adolescents with T alleles/TT homozygotes of MAOA gene or Met alleles of COMT gene exhibited more reactive aggression when exposed to low positive parenting, but less reactive aggression when exposed to high positive parenting. These findings provide the first evidence for distinct G × E interaction effects on reactive versus proactive aggression and lend further support for the differential susceptibility hypothesis. PMID:26932718

  2. Voxelwise eigenvector centrality mapping of the human functional connectome reveals an influence of the catechol-O-methyltransferase val158met polymorphism on the default mode and somatomotor network.

    Science.gov (United States)

    Markett, Sebastian; Montag, Christian; Heeren, Behrend; Saryiska, Rayna; Lachmann, Bernd; Weber, Bernd; Reuter, Martin

    2016-06-01

    Functional connections between brain regions constitute the substrate of the human functional connectome, whose topography has been discussed as an endophenotype for psychiatric disorders. Genetic influences on the entire connectome, however, have been rarely investigated so far. We tested for connectome-wide influences of the val158met (rs4860) polymorphism on the catechol-O-methyltransferase (COMT) gene by applying formal network analysis and eigenvector centrality mapping on the voxel level to resting-state functional magnetic imaging data. This approach finds brain regions that are central in the network by aggregating local and global connectivity patterns, most importantly without the requirement to select regions or networks of interest. The COMT variant linked to high enzyme activity increased network centrality in distributed brain areas that are known to constitute the brain's default mode network. Further results also indicated a COMT influence on areas implicated in the somatomotor network. These findings are in line with the polymorphism's alleged role in cognitive processing and its role in psychotic disorders. The study is the first to demonstrate the influence of a functional and behaviorally relevant genetic variant on connectome-wide functional connectivity and is an important step toward establishing the functional connectome as an endophenotype for psychiatric and behavioral phenotypes. PMID:26025199

  3. Genetic moderation of the effects of cannabis: catechol-O-methyltransferase (COMT) affects the impact of Δ9-tetrahydrocannabinol (THC) on working memory performance but not on the occurrence of psychotic experiences.

    Science.gov (United States)

    Tunbridge, Elizabeth M; Dunn, Graham; Murray, Robin M; Evans, Nicole; Lister, Rachel; Stumpenhorst, Katharina; Harrison, Paul J; Morrison, Paul D; Freeman, Daniel

    2015-11-01

    Cannabis use can induce cognitive impairments and psychotic experiences. A functional polymorphism in the catechol-O-methyltransferase (COMT) gene (Val(158)Met) appears to influence the immediate cognitive and psychotic effects of cannabis, or ∆(9)-tetrahydrocannabinol (THC), its primary psychoactive ingredient. This study investigated the moderation of the impact of experimentally administered THC by COMT. Cognitive performance and psychotic experiences were studied in participants without a psychiatric diagnosis, using a between-subjects design (THC vs. placebo). The effect of COMT Val(158)Met genotype on the cognitive and psychotic effects of THC, administered intravenously in a double-blind, placebo-controlled manner to 78 participants who were vulnerable to paranoia, was examined. The results showed interactive effects of genotype and drug group (THC or placebo) on working memory, assayed using the Digit Span Backwards task. Specifically, THC impaired performance in COMT Val/Val, but not Met, carriers. In contrast, the effect of THC on psychotic experiences, measured using the Community Assessment of Psychic Experiences (CAPE) positive dimension, was unaffected by COMT genotype. This study is the largest to date examining the impact of COMT genotype on response to experimentally administered THC, and the first using a purely non-clinical cohort. The data suggest that COMT genotype moderates the cognitive, but not the psychotic, effects of acutely administered THC. PMID:26464454

  4. Dopamine receptor D2 and catechol-O-methyltransferase gene polymorphisms associated with anorexia nervosa in Chinese Han population: DRD2 and COMT gene polymorphisms were associated with AN.

    Science.gov (United States)

    Peng, Sufang; Yu, Shunying; Wang, Qian; Kang, Qing; Zhang, Yanxia; Zhang, Ran; Jiang, Wenhui; Qian, Yiping; Zhang, Haiyin; Zhang, Mingdao; Xiao, Zeping; Chen, Jue

    2016-03-11

    Dopamine receptor D2 (DRD2) and catechol-O-methyltransferase (COMT) are important in dopamine system which is proved to be associated with food-anticipatory behavior, food restriction, reward and motivation. This has made them good candidates for anorexia nervosa (AN). The aim of this work is to explore the roles of DRD2 (rs1800497) and COMT (rs4680, rs4633, rs4818) gene polymorphisms in the susceptibility of AN within the Chinese Han population. We recruited 260AN patients with DSM-IV diagnosis criteria, and 247 unrelated, normal weight controls. DRD2 (rs1800497) and COMT (rs4680, rs4633, rs4818) were genotyped in all subjects. We found rs1800497 and rs4633 were associated with the susceptibility of AN within the Chinese Han sample, and allele C of rs1800497 was a protective factor. There was a gene-gene interaction between rs1800497 of DRD2 gene and rs4633 of COMT gene. We concluded that rs1800497 and rs4633 play important roles in the AN susceptibility with respect to the Chinese Han population. The gene-gene interaction between DRD2 and COMT contributes to the risk of AN. PMID:26808641

  5. Relationship between the catechol-O-methyl transferase Val108/158Met genotype and brain volume in treatment-naive major depressive disorder: Voxel-based morphometry analysis.

    Science.gov (United States)

    Watanabe, Keita; Kakeda, Shingo; Yoshimura, Reiji; Abe, Osamu; Ide, Satoru; Hayashi, Kenji; Katsuki, Asuka; Umene-Nakano, Wakako; Watanabe, Rieko; Nakamura, Jun; Korogi, Yukunori

    2015-09-30

    Catechol-O-methyltransferase (COMT) is a methylation enzyme engaged in the degradation of dopamine and noradrenaline by catalyzing the transfer of a methyl group from S-adenosylmethionine. An association was found between the Valine (Val) 108/158Methionine (Met) COMT polymorphism (rs4680) and major depressive disorder (MDD). The authors prospectively investigated the relationship between the Val108/158Met COMT genotype and voxel-based morphometry (VBM) findings for patients with first-episode and treatment-naïve MDD and healthy subjects (HS). Participants comprised 30 MDD patients and 48 age- and sex-matched HS who were divided according to the COMT genotype. Effects of diagnosis, COMT genotype, and the genotype-diagnosis interaction in relation to brain morphology in the Val/Met and Val/Val individuals were evaluated using a VBM analysis of high-resolution magnetic resonance imaging findings. Among the Val/Met individuals, the volume of the bilateral caudate was significantly smaller for MDD patients than for HS. In the Val/Val individuals, the caudate volume was comparable between MDD patients and HS. Significant genotype-diagnosis interaction effects on brain morphology were noted in the right caudate. PMID:26253436

  6. The Role of a Catechol-O-Methyltransferase (COMT) Val158Met Genetic Polymorphism in Schizophrenia: A Systematic Review and Updated Meta-analysis on 32,816 Subjects.

    Science.gov (United States)

    González-Castro, Thelma Beatriz; Hernández-Díaz, Yazmin; Juárez-Rojop, Isela Esther; López-Narváez, María Lilia; Tovilla-Zárate, Carlos Alfonso; Fresan, Ana

    2016-06-01

    An association between a catechol-O-methyltransferase (COMT) Val156Met (rs4680) polymorphism and schizophrenia has been reported in the literature, although no conclusive outcomes have been attained. The aim of this study was to evaluate the association of the COMT Val108/158Met polymorphism with schizophrenia in a systematic review and meta-analysis. We performed a keyword search on PubMed and EBSCO databases. All English language case-control studies published up to April 2015 were selected. A total of 67 studies were selected for inclusion. The genotype distribution of subjects with schizophrenia was compared with healthy control subjects, using allelic, additive, dominant and recessive models. The pooled results from the meta-analysis (15,565 cases and 17,251 healthy subjects) after the elimination of heterogeneity showed an association between COMT Val108/158Met and schizophrenia [recessive model: OR 1.08 CI 95 % (1.01-1.15)]. We conducted subgroup analyses according to ethnicity. An association was observed in our Caucasian population in the additive model [OR 1.21 CI 95 % (1.06-1.37)] and in the recessive model [OR 1.21 CI 95 % (1.11-1.32)], but not in the allelic or dominant models. However, when we analysed our Asian population after the elimination of heterogeneity, no evidence of a significant association was found in any of the genetic models. Our analyses indicate that there is an association between COMT Val108/158Met and schizophrenia in the general population. Furthermore, in Caucasian populations, this risk could be increased. PMID:27020768

  7. The role of catechol-O-methyl transferase Val(108/158Met polymorphism (rs4680 in the effect of green tea on resting energy expenditure and fat oxidation: a pilot study.

    Directory of Open Access Journals (Sweden)

    Rick Hursel

    Full Text Available INTRODUCTION: Green tea(GT is able to increase energy expenditure(EE and fat oxidation(FATox via inhibition of catechol-O-methyl transferase(COMT by catechins. However, this does not always appear unanimously because of large inter-individual variability. This may be explained by different alleles of the functional COMT Val108/158Met polymorphism that are associated with COMT enzyme activity; high-activity enzyme, COMT(H(Val/Val genotype, and low-activity COMT(L(Met/Met genotype. METHODS: Fourteen Caucasian subjects (BMI: 22.2±2.3 kg/m2, age: 21.4±2.2 years of whom 7 with the COMT(H-genotype and 7 with the COMT(L-genotype were included in a randomized, cross-over study in which EE and substrate oxidation were measured with a ventilated-hood system after decaffeinated GT and placebo(PL consumption. RESULTS: At baseline, EE, RQ, FATox and carbohydrate oxidation(CHOox did not differ between groups. Significant interactions were observed between COMT genotypes and treatment for RQ, FATox and CHOox (p<0.05. After GT vs. PL, EE(GT: 62.2 vs. PL: 35.4 kJ.3.5 hrs; p<0.01, RQ(GT: 0.80 vs. PL: 0.83; p<0.01, FATox(GT: 18.3 vs. PL: 15.3 g/d; p<0.001 and CHOox(GT: 18.5 vs. PL: 24.3 g/d; p<0.001 were significantly different for subjects carrying the COMT(H genotype, but not for subjects carrying the COMT(L genotype (EE, GT: 60.3 vs. PL: 51.7 kJ.3.5 hrs; NS, (RQ, GT: 0.81 vs. PL: 0.81; NS, (FATox, GT: 17.3 vs. PL: 17.0 g/d; NS, (CHOox, GT: 22.1 vs. PL: 21.4 g/d; NS. CONCLUSION: Subjects carrying the COMT(H genotype increased energy expenditure and fat-oxidation upon ingestion of green tea catechins vs, placebo, whereas COMT(L genotype carriers reacted similarly to GT and PL ingestion. The differences in responses were due to the different responses on PL ingestion, but similar responses to GT ingestion, pointing to different mechanisms. The different alleles of the functional COMT Val108/158Met polymorphism appear to play a role in the inter

  8. Executive functions and selective attention are favored in middle-aged healthy women carriers of the Val/Val genotype of the catechol-o-methyltransferase gene: a behavioral genetic study

    Directory of Open Access Journals (Sweden)

    Gutiérrez-Muñoz Mayra

    2010-10-01

    Full Text Available Abstract Background Cognitive deficits such as poor memory, the inability to concentrate, deficits in abstract reasoning, attention and set-shifting flexibility have been reported in middle-aged women. It has been suggested that cognitive decline may be due to several factors which include hormonal changes, individual differences, normal processes of aging and age-related changes in dopaminergic neurotransmission. Catechol-O-methyltransferase (COMT, a common functional polymorphism, has been related to executive performance in young healthy volunteers, old subjects and schizophrenia patients. The effect of this polymorphism on cognitive function in middle-aged healthy women is not well known. The aim of the current study was to investigate whether measures of executive function, sustained attention, selective attention and verbal fluency would be different depending on the COMT genotype and task demand. Method We genotyped 74 middle-aged healthy women (48 to 65 years old for the COMT Val158Met polymorphism. We analyzed the effects of this polymorphism on executive functions (Wisconsin Card Sorting Test, selective attention (Stroop test, sustained attention (Continuous Performance Test and word generation (Verbal Fluency test, which are cognitive functions that involve the frontal lobe. Results There were 27 women with the Val/Val COMT genotype, 15 with the Met/Met genotype, and 32 with the Val/Met genotype. Women carriers of the Val/Val genotype performed better in executive functions, as indicated by a lower number of errors committed in comparison with the Met/Met or Val/Met groups. The correct responses on selective attention were higher in the Val/Val group, and the number of errors committed was higher in the Met/Met group during the incongruence trial in comparison with the Val/Val group. Performance on sustained attention and the number of words generated did not show significant differences between the three genotypes. Conclusion These

  9. Interfacial chemistry of catechol-based nanostructures

    OpenAIRE

    Guardingo Melian, Mireia

    2015-01-01

    Los catecoles son compuestos aromáticos presentes en una gran variedad de sistemas naturales. Dada su gran versatilidad a nivel de propiedades fisicoquímicas, adquieren papeles clave en diferentes procesos naturales. Entre otros, los grupos catecol se encuentran en las proteínas adhesivas de los mejillones formando parte de aminoácido L-DOPA, que se considera responsable del extraordinario poder adhesivo de estos organismos en condiciones de extrema humedad. Este fenómeno ha fascinado a los c...

  10. Polimorfismos dos genes do receptor de serotonina (5-HT2A e da catecol-O-metiltransferase (COMT: fatores desencadeantes da fibromialgia? Serotonin receptor (5-HT 2A and catechol-O-methyltransferase (COMT gene polymorphisms: Triggers of fibromyalgia?

    Directory of Open Access Journals (Sweden)

    Josie Budag Matsuda

    2010-04-01

    fatigue, sleep disorders, anxiety, depression, memory loss, and dizziness. Although the physiological mechanisms that control fibromyalgia have not been precisely established, neuroendocrine, genetic or molecular factors may be involved in fibromyalgia. OBJECTIVE: The aim of the present study was to characterize serotonin receptor (5-HT2A and catecholO-methyltransferase (COMT gene polymorphisms in Brazilian patients with fibromyalgia and to evaluate the participation of these polymorphisms in the etiology of the disease. MATERIAL AND METHODS: Genomic DNA extracted from 102 blood samples (51 patients, 51 controls was used for molecular characterization of the 5-HT2A and COMT gene polymorphisms by PCR-RFLP. RESULTS: Analysis of the 5-HT2A polymorphism revealed a frequency of 25.49% C/C, 49.02% T/C and 25.49% T/T in patients, and of 17.65% C/C, 62.74% T/C and 19.61% T/T in the control group, with no differences between the two groups.Analysis of the COMT polymorphism in patients showed a frequency of 17.65% and 45.10% for genotypes H/H and L/H, respectively. In the control group the frequency was 29.42% for H/H and 60.78% for L/H, also with no differences between the two groups. However, there was a significant difference in the frequency of the L/L genotype between patients (37.25% and controls (9.8%, which permitted differentiation between the two groups. CONCLUSION: The L/L genotype was more frequent among fibromyalgia patients. Though considering a polygenic situation and environmental factors, the molecular study of the rs4680 SNP of the COMT gene may be helpful to the identification of susceptible individuals.

  11. Iron(III) oxidized nucleophilic coupling of catechol with o-tolidine/p-toluidine followed by 1,10-phenanthroline as new and sensitivity improved spectrophotometric methods for iron present in chemicals, pharmaceutical, edible green leaves, nuts and lake water samples

    Science.gov (United States)

    Shyla, B.; Bhaskar, C. Vijaya; Nagendrappa, G.

    2012-02-01

    A nucleophile formed from iron(III) oxidized catechol in 0.1 M hydrochloric acid couple with o-tolidine, system 1/p-toluidine, system 2 to produce dye product, λ max 520 nm. The system 1/2 obeys Beer's law in the range 0.08-8.0 μg ml -1 with molar absorptivity, Sandell sensitivity and regression coefficient values, 4.225 × 10 3/3.140 × 10 3 l mol -1 cm -1, 0.0132/0.0178 μg cm -2 and 0.9987/0.9981. Iron(II) formed from iron(III) in system 1/2 reacts with 1,10-phenanthroline, λ max 510 nm, will constitute sensitivity improved iron determinations with values 0.08-1.6 μg ml -1, 2.4136 × 10 4/2.2511 × 10 4 l mol -1 cm -1, 0.0023/0.0025 μg cm -2 and 0.9980/0.9997 corresponding to range, molar absorptivity, Sandell sensitivity and regression coefficient. The results of the systems for iron present in chemicals, pharmaceutical, edible green leaves, nuts and lake water samples are satisfactory since they are comparable with the results of iron determined separately from 1,10-phenanthroline method.

  12. Polymorphisms of catechol-O-methyltransferase and monoamine oxidase B genes among Chinese patients with Parkinson's disease%中国帕金森病患者儿茶酚-O-甲基转移酶及单胺氧化酶B基因的多态性分析

    Institute of Scientific and Technical Information of China (English)

    郝宏莹; 邵明; 安静; 陈楚霜; 冯秀丽; 谢淑; 顾朱勤; 陈彪

    2015-01-01

    目的 研究中国帕金森病患者儿茶酚-O-甲基转移酶(catechol-O-methyltransferase,COMT)及单胺氧化酶B (monoamine oxidase B,MAO-B)基因的多态性分布.方法 研究对象为由中国帕金森病研究协作组收集的来自全国共29个研究中心的1408例帕金森病患者.抽取静脉血提取基因组DNA,应用DNA自动测序仪,采用Sanger双脱氧链终止法检测COMT和MAO-B的基因型.结果 COMT rs4680 AA、AG、GG基因型的频率分别为8.9%、42.0%、49.1%;COMT rs4818 CC、CG、GG基因型的频率分别为42.5%、45.6%、11.9%;MAO-B rs1799836 A/AA、AG、G/GG基因型的频率分别为74.4%、14.1%、11.5%;COMTrs4680和MAO-B rs1799836基因型同时为高活性的比例为36.86%.结论 中国帕金森病患者COMT及MAOB基因多态性分布特点具有其独特特征,可能与帕金森病患者药物疗效差异存在一定的相关性.%Objective To study polymorphisms of catechol-O-methyltransferase (COMT) and monoamine oxidase B (MAO-B) genes among Chinese patients with Parkinson' s disease.Methods Genotypes of the COMT and MAO-B genes of 1408 patients with Parkinson's disease was sequenced using Sanger method.And these patients were recruited by Chinese Parkinson Study Group from 29 research centers throughout the country.Results The genotypic frequencies of COMT rs4680 AA,AG,GG were 8.9%,42.0% and 49.1%.Those of rs4818 CC,CG,GG were 42.5%,45.6% and 11.9%,respectively.The genotype frequencies of MAO-B rs1799836 A/AA,AG,G/GG were 74.4%,14.1% and 11.5%,respectively.The haplotype formed by COMT rs4680 (GG) and MAO-B rs1799836 (A/AA) genotype has a frequency of 36.86%.Conclusion Polymorphisms of COMT and MAO-B genes has a unique characteristics among Chinese patients with Parkinson's disease.They may be related with differences in drug response in such patients.

  13. 金/钴氢氧化物膜修饰玻碳电极同时测定邻苯二酚和对苯二酚%Simultaneous Determination of Catechol and Hydroquinone at Cobalt Hydroxide Film/Gold Nanoparticles Modified Glassy Carbon Electrode

    Institute of Scientific and Technical Information of China (English)

    侯宏卫; 张小涛; 陈欢; 刘彤; 唐纲岭; 胡清源

    2013-01-01

    文章将纳米金与钴氢氧化物膜的催化作用有效结合,制备了GNPs/CoOOH复合修饰电极,该修饰电极在碱性条件下对邻苯二酚和对苯二酚具有较强的电催化活性.考察了支持电解质酸度及纳米金沉积时间对邻苯二酚和对苯二酚电化学响应的影响,选取0.1 mol/L PBS (pH 10.0)作为支持电解质,纳米金的最佳沉积时间为4min.在优化的实验条件下,利用差示脉冲伏安法(DPV)对邻苯二酚和对苯二酚进行选择性检测:当两者浓度同时改变时,对苯二酚和邻苯二酚的氧化峰电流与其浓度分别在7~100 μmol/L和6~100 μmol/L范围内呈良好的线性关系,对应的检出限分别为0.9、0.8 μmol/L(S/N=3).该复合修饰电极具有较好的重现性、稳定性及较强的抗干扰能力.%Combing the advantageous features of gold nanoparticles (GNPs) and cobalt hydroxide film (CoOOH),GNPs/CoOOH composite film was prepared on the surface of glassy carbon electrode.Under alkaline solutions,the modified electrode exhibited excellent electrocatalytic activities towards catechol (CA) and hydroquinone (HQ).Effects of pH value and electrodeposition time of GNPs on the oxidation peak current of catechol and hydroquinone were studied by differential pulse voltammetry (DPV).The optimized pH value and electrodeposition time were separately 10.0 (0.1 mol/L PBS) and 4 min.Under the optimized conditions,the oxidation peak current of HQ and CA were separately linearly with concentration of CA in the range of 7~100 μmol/L and 6~100 μmol/L with the detection limit of 0.9 μmol/L (S/N--3) for HQ and 0.8μmol/L (S/N=3) for CA.The modified electrode exhibited good producibility,stability and selectivity.

  14. 铁离子促进过量多巴胺引起SH-SY5Y细胞儿茶酚异喹啉物质生成和氧化损伤%Iron contributes to the formation of catechol isoquinolines and oxidative toxicity induced by overdose dopamine in dopaminergic SH-SY5Y cells

    Institute of Scientific and Technical Information of China (English)

    王冉; 庆宏; 刘晓茜; 郑晓琳; 邓玉林

    2008-01-01

    Objective The selective loss of dopaminergic neurons in Parkinson's disease is suspected to correlate with the increase of cellular iron,which may be involved in the pathogenesis of PD by promotion of oxidative stress.This research investigated dopamine-induced oxidative stress toxicity contributed by iron and the production of dopamine-derived neurotoxins in dopaminergic SH-SY5Y cells.Methods After the SH-SY5Y cells were pre-incubated with dopamine and Fe2+ for 24 h,the cell viability,hydroxyl radical,melondialdehyde,cell apoptosis,and catechol isoquinolines were measured by lactate dehydrogenase assay,salicylic acid trapping method,thiobarbuteric acid assay,Hoechst 33258 staining and HPLC-electrochemical detection (HPLC-ECD),respectively.Results (1) Optimal dopamine (150 μmol/L) and Fe2+ (40 or 80 μmol/L)significantly increased the concentrations of hydroxy radicals and melondialdehyde in SH-SY5Y cells.(2) Induction with dopamine alone or dopamine and Fe2+ (dopamine/Fe2+) caused cell apoptosis.(3) Compared with untreated cells,the catechol isoquinolines,salsolinol and N-methyl-salsolinol in dopamine/Fe2+-induced cells were detected in increasing amounts.Conclusion Due to dopamine/Fe2+-induced oxidative stress similar to the state in the parkinsonian substantia nigra neurons,dopamine and Fe2+ impaired SH-SY5Y cells could be used as the cell oxidative stress model of Parkinson's disease.The catechol isoquinolines detected in cells may be involved in the pathogenesis of Parkinson's disease as potential neurotoxins.%目的 帕金森氏病(Pakinson's disease,PD)中多巴胺能神经元选择性缺失与胞内铁水平升高有密切关系,提示铁可能通过参与氧化应激在PD发病机制中起重要作用.本研究使用一定浓度的Fe2+和多巴胺诱导人多巴胺能成神经细胞瘤SH-SY5Y细胞产生氧化应激状态,并且检测胞内是否有多巴胺衍生类的神经内毒素物质产生.方法 多巴胺添加不同浓度的Fe2+诱导SH.SY5Y

  15. A catechol biosensor based on electrospun carbon nanofibers

    OpenAIRE

    Dawei Li; Zengyuan Pang; Xiaodong Chen; Lei Luo; Yibing Cai; Qufu Wei

    2014-01-01

    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 empl...

  16. Pessoine and spinosine, two catecholic berbines from Annona spinescens

    OpenAIRE

    Queiroz, E.F.; Roblot, F.; Cavé, A.; Marçal de Q., P.; Fournet, Alain

    1996-01-01

    The trunk bark and roots of #Annona spinescens$ have been investigated for their alkaloid content. Two new berbine alkaloids, pessoine and spinosine, have been isolated from the bark, and their structures were elucidated by spectroscopic methods. Eight known isoquinoline alkaloids were also obtained. The trypanocidal and antileishmanial activities of these isolated compounds have been investigated. (Résumé d'auteur)

  17. Radioimmunoassay and metabolism of the catechol estrogen 2-hydroxyestradiol

    International Nuclear Information System (INIS)

    Plasma levels of 2-hydroxyestradiol (2-OHE2) were measured using a new RIA procedure. Values were below the detection limit of the assay (2 elevated its plasma concentration to 155 pg/ml, consistent with a plasma MCR (MCR/sub p) of approximately 20,000 liters/day. The infusion of [3H]2-OHE2 to equilibrium and chromatographic separation of the extracted plasma metabolites yielded an MCR/sub p/ of about 13,000 liters/day; the major plasma metabolite comigrated with 2-methoxyestradiol, and [3H]delta-methoxyestrone was also formed. The MCR/sub p/ of 2-OHE2 is approximately half that of 2-hydroxyestrone (2-OHE)1, but much higher than those of other steroids. As is true for 2-OHE1 the clearance of 2-OHE2 must occur primarily in the blood compartment. Together, the measured MCR/sub p/ values and estrogen receptor affinities of 2-OHE2 and 2-OHE1 predict a relative potency for effects upon gonadotropin secretion which is close to that observed in vivo

  18. Identification of catechols as histone-lysine demethylase inhibitors

    DEFF Research Database (Denmark)

    Nielsen, Anders L; Kristensen, Line H; Stephansen, Karen B; Kristensen, Jan B L; Helgstrand, Charlotte; Lees, Michael; Cloos, Paul; Helin, Kristian; Gajhede, Michael; Olsen, Lars

    2012-01-01

    Identification of inhibitors of histone-lysine demethylase (HDM) enzymes is important because of their involvement in the development of cancer. An ELISA-based assay was developed for identification of inhibitors of the HDM KDM4C in a natural products library. Based on one of the hits with affinity...

  19. An association study on Catechol-O-methyl transferase polymorphism and obsessive-compulsive disorder and obsessive-compulsive disorder comorbid with bipolar disorder%儿茶酚氧位甲基转移酶基因多态性与单纯强迫症及共病双相障碍强迫症的关联分析

    Institute of Scientific and Technical Information of China (English)

    刘玉平; 苗国栋; 徐昌武; 刘恩益

    2012-01-01

    目的 探讨中国汉族人群中儿茶酚氧位甲基转移酶(COMT)基因多态性与单纯强迫症以及共病双相障碍强迫症之间的关系.方法 按美国《精神疾病诊断与统计手册》(DSM-Ⅳ),对符合诊断标准的单纯强迫症患者(单纯强迫症组)86例、共病双相障碍的强迫症患者(共病组)76例和正常对照(正常对照组)120例分别应用聚合酶链式反应(PCR)及限制性片段长度多态性(RFLP)技术检测COMT基因的多态性,采用病例-对照的关联分析方法对3组基因型和等位基因频率进行分析.结果 3组COMT基因型符合Hardy-Weinberg平衡法则;COMT的基因型和等位基因频率分布在3组间差异无统计学意义(P>0.05);经性别分层后,3组中COMT基因型与等位基因频率的分布差异也无统计学意义(P>0.05).结论 COMT基因多态性与单纯强迫症及共病双相障碍的强迫症可能无关联.%Objective To explore the association between polymorphism of Catechol-O-methyl transferase (COMT) gene and the pathogenesis of obsessive-compulsive disorder (OCD) and obsessive-compulsive disorder comorbid with bipolar disorder (BD) in the Han nationality.Methods According to the Diagnostic and Statistical Manual of Mental Disorders( DSM-IV ),86 patients were recruited according to the diagnosis criteria of OCD and 76 patients were recruited according to the diagnosis criteria of BD and OCD.One hundred and twenty healthy persons were in the control group.All the subjects were genotyped directly with the polymerase chain reaction-restriction fragment length polymorphism technique.The case-control association analysis was adopted to analyze the frequencies of genotype and alleles among the three groups.Results The values of the genotypes of the three groups were consistent with the Hardy-Weinberg equilibrium; there were no significant differences among the three groups regarding genotypes or alleles of COMT gene.Even stratified by sex,the distribution

  20. 儿茶酚氧位甲基转移酶基因多态性与中国南方人群精神分裂症的关联研究%Association analysis of catechol-O-methyltransferase gene polymorphisms with schizophrenia in southern Chinese population

    Institute of Scientific and Technical Information of China (English)

    江娟; 韦波; 龙建雄; 凌维俊; 黄桂凤; 苏莉

    2015-01-01

    Objective To explore the association of catechol-O-methyhransferase(COMT) gene polymorphisms with schizophrenia susceptibility and its symptoms assessed by Positive and Negative Syndrome Scale (PANSS)in southern Chinese population.Methods COMT gene rs4633,rs4680 and rs8185002 polymorphisms were genotyped using Sequenom genotyping technology in 700 schizophrenia patients (300 Zhuang and 400 Han) and 700 healthy controls (300 Zhuang and 400 Han),and Positive and Negative Syndrome Scale (PANSS) was used for clinical symptoms assessment of patients.Statistical analysis was performed using PLINK software.Results rs4633,rs4680 and rs8185002 polymorphisms were not significantly associated with schizophrenia susceptibility in Zhuang or Han population respectively(P>0.05).After merging Zhuang and Han samples,rs4633(I 2 =0.000,Pmeta =0.040) and rs4680 (I2=0.000,Pmeta =0.014) were significantly associated with the susceptibility to schizophrenia.In addition,haplotype T-A-T was significantly associated with schizophrenia susceptibility (P=0.049).However,these three polymorphisms were not significantly associated with total score,positive scale score,negative scale score and general psychopathology scale score assessed by PANSS(P>0.05).Conclusion COMT gene rs4633 and rs4680 polymorphisms are involved in the susceptibility to schizophrenia in southern Chinese population.%目的 探讨儿茶酚氧位甲基转移酶基因多态性与中国南方人群精神分裂症易感性及PANSS测评症状之间的关联.方法 采用Sequenom基因分型技术,在700例病例(壮族300例,汉族400例)和700例对照(壮族300例,汉族400例)中,对COMT基因rs4633 、rs4680和rs8185002进行基因分型,并采用阳性与阴性症状量表(PANSS)对患者进行症状测评.采用PLINK软件进行统计学分析.结果 分别在壮族样本、汉族样本中,这三个位点与精神分裂症易感性的关联差异无统计学意义(P>0.05).合并两民族样本后,rs4633(I2

  1. Analysis of the association between the polymorphism of catechol-o-methyltransferase and monoamine oxidase A and the obsessive-compulsive disorder in nuclear families in Han nationality%汉族核心家系中强迫症与儿茶酚胺氧位甲基转移酶和单胺氧化酶基因多态性的关联分析

    Institute of Scientific and Technical Information of China (English)

    牛亚楠; 张红星; 梁炜; 胡宪章; 陈佐明

    2011-01-01

    Objective To explore the association between val158met polymorphism of catechol-O-methyltransferase ( COMT ) gene and T941G polymorphism of monoamine oxidase A ( MAOA ) gene and obsessive-compulsive disorder ( OCD ) in nuclear families in Han nationality. Methods One hundred thirty four OCD patients of Han nationality and their biological parents were included in this study. DNA was genotyped using specific sequence polymerase chain reaction ( SSPCR ) and allele inheritance was examined using the transmission disequilibrium test ( TDT ) and haplotype relative risk ( HRR ) test. Results One hundred twelve and 103 out of 134 nuclear families were analyzed for COMT gene and MAOA gene under TDT and HRR, respectively. There was no transmission disequilibrium exist for COMT gene val158met polymorphism ( TDT: P = 0.15 , HRR: x2 = 3.58. P = 0.06 ) while there was significant transmission disequilibrium in TDT ( x2 = 4.78, P =0.04 ) and HRR( x2 =7.63 , P =0.01 )for MAOA gene T941G polymorphism. The rate of allele T transmitted to the children was 57.22% . Conclusions This study suggests that MAOA gene T941G polymorphism may be associated with OCD while COMT gene may not he directly associated with OCD in our patient population.%目的 分析儿茶酚胺氧位甲基转移酶(catechol-O-methyltransferase,COMT)基因和单胺氧化酶(monoamine oxidases A, MAOA)基因T941G多态位点与汉族强迫症的关联.方法 应用特异性引物序列聚合酶链反应检测134个强迫症核心家系(患者及其生物学父母)的COMT基因val158met和MAOA基因T941G多态性.采用单体型相对危险度分析(haplotype relative risk,HRR)及传递不平衡检验(transmission disequilibrium test, TDT)进行关联分析.结果 112个和103个核心家系分别进入COMT基因和MAOA基因的TDT和HRR分析.TDT检测McNemar检验(P=0.15)及HRR检测( χ 2=3.58, P=0.06)均不支持COMT val158met多态位点存在传递不平衡; MAOA基因T941G位点的TDT( χ 2=4.78, P=0.04)

  2. Catechol-o-methyltransferase polymorphism and susceptibility to major depressive disorder modulates psychological stress response

    NARCIS (Netherlands)

    Jabbi, Mbemba; Kema, Ido R.; van der Pompe, Gieta; Meerman, Gerard J. te; Ormel, Johan; den Boer, Johan A.

    2007-01-01

    Objectives The stress response is related to both physiological and psychological factors and is strongly marked by a neuroendocrine component. Genetic factors are believed to underlie individual differences in the degree of stress resilience and thereby contribute in determining susceptibility to s

  3. Synthesis of two 14C-labeled catechol-o-methyltransferase inhibitors

    International Nuclear Information System (INIS)

    14C-labelled 3-(3,4-dihydroxy-5-nitrophenylmethylidene)-2,4-pentanedione and 14C-labelled E-N,N-diethyl-2-cyano-3-(3,4-dihydroxy-5-nitrophenyl)acrylamide have been synthesized from [carbonyl-14C]vanillin. (author)

  4. Biosynthesis, solubilization and purification of human membrane bound catechol-O-methyltransferase in brevibacillus choshinensis cells

    OpenAIRE

    Pedro, Augusto Quaresma Henriques

    2011-01-01

    As proteínas membranares constituem cerca de 20 a 30 % de todas as proteínas codificadas pelo genoma de vários organismos. Elevadas quantidades de proteínas num estado de elevada pureza são necessárias quer para estudos farmacológicos, quer para estudos cristalográficos, daí a imperativa necessidade de desenvolver novos sistemas para a sobre-expressão heteróloga de proteínas membranares. Especificamente, nós testámos a aplicação de Brevibacillus choshinensis para a biosíntese d...

  5. In vitro and in vivo activities of LB10522, a new catecholic cephalosporin.

    OpenAIRE

    Kim, M.Y.; Oh, J. I.; Paek, K S; Kim, Y Z; Kim, I. C.; Kwak, J. H.

    1996-01-01

    In vitro activity of LB10522 was compared with those of cefpirome, ceftazidime, ceftriaxone, and cefoperazone against clinical isolates. Against gram-positive bacteria, LB10522 was most active among the compounds tested. It was fourfold more active than cefpirome against methicillin-susceptible Staphylococcus aureus and Enterococcus faecalis. LB10522 was highly effective against most members of the family Enterobacteriaceae tested. Ninety percent of isolates of Escherichia coli, Klebsiella ox...

  6. Fusing catechol-driven surface anchoring with rapid hetero Diels-Alder ligation

    Czech Academy of Sciences Publication Activity Database

    Preuss, C. M.; Zieger, M. M.; Rodriguez-Emmenegger, Cesar; Zydziak, N.; Trouillet, V.; Goldmann, A. S.; Barner-Kowollik, C.

    2014-01-01

    Roč. 3, č. 11 (2014), s. 1169-1173. ISSN 2161-1653 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0109; GA ČR GBP205/12/G118 Institutional support: RVO:61389013 Keywords : nanoparticles * biosensors * polymer brushes Subject RIV: BO - Biophysics Impact factor: 5.764, year: 2014

  7. The Role of the Catechol-O-Methyltransferase (COMT) Gene in Personality and Related Psychopathological Disorders

    OpenAIRE

    Montag, Christian; Jurkiewicz, Magdalena; Reuter, Martin

    2012-01-01

    This review provides a short overview of the most significant biologically oriented theories of human personality. Personality concepts of Eysenck, Gray and McNaughton, Cloninger and Panksepp will be introduced and the focal evidence for the heritability of personality will be summarized. In this context, a synopsis of a large number of COMT genetic association studies (with a focus on the COMT Val158Met polymorphism) in the framework of the introduced biologically oriented personality theori...

  8. Production of the catechol type siderophore bacillibactin by the honey bee pathogen Paenibacillus larvae.

    Science.gov (United States)

    Hertlein, Gillian; Müller, Sebastian; Garcia-Gonzalez, Eva; Poppinga, Lena; Süssmuth, Roderich D; Genersch, Elke

    2014-01-01

    The Gram-positive bacterium Paenibacillus larvae is the etiological agent of American Foulbrood. This bacterial infection of honey bee brood is a notifiable epizootic posing a serious threat to global honey bee health because not only individual larvae but also entire colonies succumb to the disease. In the recent past considerable progress has been made in elucidating molecular aspects of host pathogen interactions during pathogenesis of P. larvae infections. Especially the sequencing and annotation of the complete genome of P. larvae was a major step forward and revealed the existence of several giant gene clusters coding for non-ribosomal peptide synthetases which might act as putative virulence factors. We here present the detailed analysis of one of these clusters which we demonstrated to be responsible for the biosynthesis of bacillibactin, a P. larvae siderophore. We first established culture conditions allowing the growth of P. larvae under iron-limited conditions and triggering siderophore production by P. larvae. Using a gene disruption strategy we linked siderophore production to the expression of an uninterrupted bacillibactin gene cluster. In silico analysis predicted the structure of a trimeric trithreonyl lactone (DHB-Gly-Thr)3 similar to the structure of bacillibactin produced by several Bacillus species. Mass spectrometric analysis unambiguously confirmed that the siderophore produced by P. larvae is identical to bacillibactin. Exposure bioassays demonstrated that P. larvae bacillibactin is not required for full virulence of P. larvae in laboratory exposure bioassays. This observation is consistent with results obtained for bacillibactin in other pathogenic bacteria. PMID:25237888

  9. Mussel-inspired soft-tissue adhesive based on poly(diol citrate) with catechol functionality.

    Science.gov (United States)

    Ji, Yali; Ji, Ting; Liang, Kai; Zhu, Lei

    2016-02-01

    Marine mussels tightly adhering to various underwater surfaces inspires human to design adhesives for wet tissue adhesion in surgeries. Characterization of mussel adhesive plaques describes a matrix of proteins containing 3,4-dihydroxyphenylalanine (DOPA), which provides strong adhesion in aquatic conditions. Several synthetic polymer systems have been developed based on this DOPA chemistry. Herein, a citrate-based tissue adhesives (POEC-d) was prepared by a facile one-pot melt polycondensation of two diols including 1,8-octanediol and poly(ethylene oxide) (PEO), citric acid (CA) and dopamine, and the effects of hydrophilic and soft PEO on the properties of adhesives were studied. It was found that the obtained adhesives exhibited water-soluble when the mole ratio of PEO to 1,8-octanediol was 70%, and the equilibrium swelling percentage of cured adhesive was about 144%, and degradation rate was in the range of 1-2 weeks. The cured adhesives demonstrated soft rubber-like behavior. The lap shear adhesion strength measured by bonding wet pig skin was in the range of 21.7-33.7 kPa, which was higher than that of commercial fibrin glue (9-15 kPa). The cytotoxicity tests showed the POEC-d adhesives had a low cytotoxicity. Our results supports that POEC-d adhesives, which combined strong wet adhesion with good biodegradability, acceptable swelling ratio, good elasticity and low cytotoxicity, have potentials in surgeries where surgical tissue adhesives, sealants, and hemostatic agents are used. PMID:26704547

  10. Properties of the Membrane Binding Component of Catechol-O-methyltransferase Revealed by Atomistic Molecular Dynamics Simulations

    DEFF Research Database (Denmark)

    Orlowski, A.; St-Pierre, J. F.; Magarkar, A.;

    2011-01-01

    helical segment brought about an interesting view that the flexible loop observed in our work can be a common structural element in these types of proteins. In the same spirit we close the article by discussing the role of salt bridges in the formation of three-dimensional structures of membrane proteins...... that was not included in our model. In numerous independent simulations we observed the formation of a salt bridge between ARC 27 and GLU40. The salt bridge closed the flexible loop that formed in the linker and kept it in the vicinity of the membrane-water interface. All simulations supported this...

  11. The SPASIBA Force Field for Studying Iron-Tannins Interactions : Application to Fe3+ /Fe2+ Catechol Complexe

    OpenAIRE

    Vergoten, G; P. Lagant; D. Yapo-Kicho

    2007-01-01

    The SPASIBA force field parameters have been obtained for Fe3+/Fe2+-Oxygen interactions occuring between non-heminic iron and hydroxyl groups of polyphenols found in tannins. These parameters were derived from normal modes analyses based on quantum chemical calculations using the Density Functional Theory (DFT). Four models involving complexation of iron with water ([Fe(H2O)6]3+, [Fe(H2O)6]2+) and with cathechol molecules ([Fe(cat)2(H2O)2]−1, [Fe(cat)2(H2O)2]−2) were studied using the Density...

  12. Fabricated catecholic films are capable of redox-cycling and H2O2-generation in the absence of enzymes

    Science.gov (United States)

    The redox activity of quinones is integral to their physiological function in the electron transfer pathways of respiration and photosynthesis. Quinones and phenolic radicals are also intermediates in the biosynthesis of macromolecular structures (lignins and melanins) generated by plants and insec...

  13. Tyrosinase and catechol oxidase activity of copper(I) complexes supported by imidazole-based ligands: structure-reactivity correlations.

    Science.gov (United States)

    Wendt, Franziska; Näther, Christian; Tuczek, Felix

    2016-09-01

    Four new imidazole-based ligands, 4-((1H-imidazol-4-yl)methyl)-2-phenyl-4,5-dihydrooxyzole (L OL 1), 4-((1H-imidazol-4-yl)methyl)-2-(tert-butyl)-4,5-dihydrooxyzole (L OL 2), 4-((1H-imidazol-4-yl)methyl)-2-methyl-4,5-dihydrooxyzole (L OL 3), and N-(2,2-dimethylpropylidene)-2-(1-trityl-1H-imidazol-4-yl-)ethyl amine (L imz 1), have been synthesized. The corresponding copper(I) complexes [Cu(I)(L OL 1)(CH3CN)]PF6 (CuL OL 1), [Cu(I)(L OL 2)(CH3CN)]PF6 (CuL OL 2), [Cu(I)(L OL 3)(CH3CN)]PF6 (CuL OL 3), [Cu(I)(L imz 1)(CH3CN)2]PF6 (CuL imz 1) as well as the Cu(I) complex derived from the known ligand bis(1-methylimidazol-2-yl)methane (BIMZ), [Cu(I)(BIMZ)(CH3CN)]PF6 (CuBIMZ), are screened as catalysts for the oxidation of 3,5-di-tert-butylcatechol (3,5-DTBC-H2) to 3,5-di-tert-butylquinone (3,5-DTBQ). The primary reaction product of these oxidations is 3,5-di-tert-butylsemiquinone (3,5-DTBSQ) which slowly converts to 3,5-DTBQ. Saturation kinetic studies reveal a trend of catalytic activity in the order CuL OL 3 ≈ CuL OL 1 > CuBIMZ > CuL OL 2 > CuL imz 1. Additionally, the catalytic activity of the copper(I) complexes towards the oxygenation of monophenols is investigated. As substrates 2,4-di-tert-butylphenol (2,4-DTBP-H), 3-tert-butylphenol (3-TBP-H), 4-methoxyphenol (4-MeOP-H), N-acetyl-L-tyrosine ethyl ester monohydrate (NATEE) and 8-hydroxyquinoline are employed. The oxygenation products are identified and characterized with the help of UV/Vis and NMR spectroscopy, mass spectrometry, and fluorescence measurements. Whereas the copper complexes with ligands containing combinations of imidazole and imine functions or two imidazole units (CuL imz 1 and CuBIMZ) are found to exhibit catalytic tyrosinase activity, the systems with ligands containing oxazoline just mediate a stoichiometric conversion. Correlations between the structures of the complexes and their reactivities are discussed. PMID:27333775

  14. Influence of Chemical Kinetics on Postcolumn Reaction in a Capillary Taylor Reactor with Catechol Analytes and Photoluminescence Following Electron Transfer

    OpenAIRE

    Jung, Moon Chul; Weber, Stephen G.

    2005-01-01

    Postcolumn derivatization reactions can enhance detector sensitivity and selectivity, but their successful combination with capillary liquid chromatography has been limited because of the small peak volumes in capillary chromatography. A capillary Taylor reactor (CTR), developed in our laboratory, provides simple and effective mixing and reaction in a 25-μm-radius postcolumn capillary. Homogenization of reactant streams occurs by radial diffusion, and a chemical reaction follows. Three charac...

  15. Laccase immobilization on the electrode surface to design a biosensor for the detection of phenolic compound such as catechol

    Science.gov (United States)

    Nazari, Maryam; Kashanian, Soheila; Rafipour, Ronak

    2015-06-01

    Biosensors based on the coupling of a biological entity with a suitable transducer offer an effective route to detect phenolic compounds. Phenol and phenolic compounds are among the most toxic environmental pollutants. Laccases are multi-copper oxidases that can oxide phenol and phenolic compounds. A method is described for construction of an electrochemical biosensor to detect phenolic compounds based on covalent immobilization of laccase (Lac) onto polyaniline (PANI) electrodeposited onto a glassy carbon (GC) electrode via glutaraldehyde coupling. The modified electrode was characterized by voltammetry, Fourier transform infrared (FTIR) spectroscopy and atomic force microscopy (AFM) techniques. The results indicated that laccase was immobilized onto modified GC electrode by the covalent interaction between laccase and terminal functional groups of the glutaraldehyde. The laccase immobilized modified electrode showed a direct electron transfer reaction between laccase and the electrode. Linear range, sensitivity, and detection limit for this biosensor were 3.2 × 10-6 to 19.6 × 10-6 M, 706.7 mA L mol-1, 2.07 × 10-6 M, respectively.

  16. Catechol-based substrates of chalcone synthase as a scaffold for novel inhibitors of PqsD.

    OpenAIRE

    Allegretta, Giuseppe; Weidel, Elisabeth; Empting, Martin; Hartmann, Rolf W.

    2015-01-01

    A new strategy for treating Pseudomonas aeruginosa infections could be disrupting the Pseudomonas Quinolone Signal (PQS) quorum sensing (QS) system. The goal is to impair communication among the cells and, hence, reduce the expression of virulence factors and the formation of biofilms. PqsD is an essential enzyme for the synthesis of PQS and shares some features with chalcone synthase (CHS2), an enzyme expressed in Medicago sativa. Both proteins are quite similar concerning the size of the ac...

  17. Catechol-O-Methyltransferase (COMT) Modulation of Cortisol Secretion in Psychiatrically At-risk and Healthy Adolescents

    OpenAIRE

    Walder, Deborah J; Trotman, Hanan D.; Cubells, Joseph F.; Brasfield, Joy; Tang, Yilang; Walker, Elaine F.

    2010-01-01

    Recent research implicates the COMT Val108/158Met polymorphism in stress-sensitivity, via modulation of hypothalamic-pituitary-adrenal (HPA) function. In healthy samples, Met-homozygosity has been associated with greater HPA activity (i.e., cortisol) and stress sensitivity, though findings are mixed among clinical samples. To date, there are no reports examining baseline or longitudinal changes in HPA activity as a function of COMT genotype in youth. This study examined the association of COM...

  18. Rate enhancement of the catechol oxidase activity of a series of biomimetic monocopper(II) complexes by introduction of non-coordinating groups in N-tripodal ligands

    OpenAIRE

    Marion, Ronan; Saleh, Nidal; Le Poul, Nicolas; Floner, Didier; Lavastre, Olivier; Geneste, Florence

    2012-01-01

    International audience Asymmetrical N-tripodal ligands have been synthesized in three steps. Diversity has been introduced at the first step of the synthesis by adding pyrazine, pyridine, benzyl and thiophene rings. The corresponding CuII complexes have been prepared by reaction with CuCl2 and characterized by Electron Paramagnetic Resonance (EPR), UV-Vis spectroscopies and cyclic voltammetry. The data show that the ligand coordinates to CuII in a mononuclear fashion in solution and that t...

  19. Biotransformation of Catechol from Phenol Catalyzed by immobilized Polyphenol Oxidase%固定化多酚氧化酶催化合成邻苯二酚

    Institute of Scientific and Technical Information of China (English)

    崔焱; 李刚; 孟雅; 张龙

    2006-01-01

    利用壳聚糖固定化蘑菇多酚氧化酶催化氧化苯酚合成邻苯二酚,考察了固定化多酚氧化酶羟基化反应条件对目的产物产率的影响.确定适宜的羟基化工艺条件为:以氯仿为溶剂、底物浓度为20 mmol·L-1,pH值为7.0,含水量为0.9%、温度为30℃、反应时间为5 h,在此条件下催化合成邻苯二酚的产率为11.02%.

  20. Effect of monoamine oxidase A and B and of catechol-O-methyltransferase inhibition on L-DOPA-indnced circling behavior

    NARCIS (Netherlands)

    Heeringa, MJ; dAgostini, F; DeBoer, P; DaPrada, M; Damsma, G

    1997-01-01

    The effect of enzyme-inhibiting adjuvants on L-DOPA + benserazide-induced contralateral turning in unilateral 6-hydroxydopamine (6-OHDA)-lesioned rats was studied. Both the number of turns and the duration of turning were examined. Inhibition of MAO-A with 10 mg/kg Ro 41-1049 increased both paramete

  1. Competitive coordination aggregation for V-shaped [Co3] and disc-like [Co7] complexes: synthesis, magnetic properties and catechol oxidase activity.

    Science.gov (United States)

    Singha Mahapatra, Tufan; Basak, Dipmalya; Chand, Santanu; Lengyel, Jeff; Shatruk, Michael; Bertolasi, Valerio; Ray, Debashis

    2016-09-14

    Unique dependence on the nature of metal salt and reaction conditions for coordination assembly reactions of varying architecture and nuclearity have been identified in V-shaped [Co3L4] and planar disc-like [Co7L6] compounds: [CoL2(μ-L)2(μ-OH2)2(CF3CO2)2] (1) and [Co(μ-L)6(μ-OMe)6]Cl2 (2) (HL = 2-{(3-ethoxypropylimino)methyl}-6-methoxyphenol). At room temperature varying reaction conditions, cobalt-ligand ratios and use of different bases allowed unique types of coordination self-assembly. The synthetic marvel lies in the nature of aggregation with respect to the two unrelated cores in 1 and 2. Complex 1 assumes a V-shaped arrangement bound to L(-), water and a trifluoroacetate anion, while 2 grows around a central Co(II) ion surrounded by a {Co} hexagon bound to methoxide and L(-). Magnetic measurements revealed that the intermetallic interactions are antiferromagnetic in nature in the case of complex 1 and ferromagnetic in the case of 2 involving high spin cobalt(ii) ions with stabilization of the high-spin ground state in the latter case. In MeCN solutions complexes 1 and 2 showed catalytic oxidation of 3,5-di-tert-butylcatechol (3,5-DTBCH2) to 3,5-di-tert-butylbenzoquinone (3,5-DTBQ) in air. The kinetic study in MeCN revealed that with respect to the catalytic turnover number (kcat) 2 is more effective than 1 for oxidation of 3,5-DTBCH2. PMID:27510847

  2. New avenues for ligand-mediated processes: expanding metal reactivity by the use of redox-active catechol, o-aminophenol and o-phenylenediamine ligands

    NARCIS (Netherlands)

    D.L.J. Broere; R. Plessius; J.I. van der Vlugt

    2015-01-01

    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 r

  3. PET studies of peripheral catechol-O-methyltransferase in non-human primates using (18F)Ro41-0960

    International Nuclear Information System (INIS)

    We previously reported the results of PET (positron emission tomography) studies of [18F]Ro41-0960, a potent COMT inhibitor, in baboon brain. Here we report an evaluation of the pharmacokinetics and specificity of binding of [18F]Ro41-0960 in the peripheral organs of baboon. We observed a rapid clearance of the tracer from the heart and no significant uptake in the lung. In contrast, there was a high uptake and slow clearance in both kidney and liver, consistent with a high level of COMT in these peripheral organs. We also observed a dose-dependent inhibition of [18F]Ro41-0960 uptake by unlabeled Ro41-0960 (ED50 was 0.5 mg/kg in liver, and 18F]Ro41-0960 may be a useful radiotracer for future examination of the functional activity of COMT in the human body. (author)

  4. Radioenzymatic assay of plasma adrenaline and noradrenaline: evidence for a catechol-O-methyltransferase (COMT) inhibiting factor associated with essential hypertension

    International Nuclear Information System (INIS)

    During the evaluation of a modified radioenzymatic determination of plasma adrenaline and noradrenaline, it has been found that there exists a highly significant (p0C, but only in plasma from patients with essential hypertension. Plasma from normotensive persons exhibits a complete lack of correlation between these factors. The consequences of the hypertension-associated COMT-inhibiting factor for the assays' specifications are discussed and data are presented for comparison with a recently-described uremia-associated COMT-inhibitor (Demassieux et al, Clin Chim Acta 115, 377-391; 1981). (Auth.)

  5. Studies on the meta and para O-sulphation of the catechol compound 3,4-dihydroxybenzoic acid by rat liver sulphotransferase in vitro.

    Science.gov (United States)

    Pennings, E J; Van Kempen, G M

    1980-01-01

    The enzymic meta and para O-sulphation of 3,4-dihydroxybenzoic acid was investigated in vitro with a dialysed high-speed supernatant from rat liver. The O-sulphated products were identified by comparison with the reference compounds. The chemical synthesis and identification of the reference O-sulphate esters is described in detail. The sulphotransferase activity of the dialysed supernatant from rat liver towards 3,4-dihydroxybenzoic acid was 580 pmol of 3-O-sulphate and 120 pmol of 4-O-sulphate formed/min per mg of protein at the optimal pH of 7.4. The meta/para ratio of O-sulphation was independent of pH, time of incubation, concentration of enzyme and presence of dithiothreitol. The O-sulphate esters of 3,4-dihydroxybenzoic acid were found to be good substrates for the arylsulphatase reaction at pH 5.6. The arylsulphatase activity of a dialysed preparation from rat liver was 4.0 nmol of 3-O- and 5.7 nmol of 4-O-sulphate ester hydrolysed/min per mg of protein, respectively. Arylsulphatase from Helix pomatia had an activity of 620 pmol of 3-O-sulphate and of 16.6 nmol of 4-O-sulphate ester hydrolysed/min per unit (mumol/h) of sulphatase. PMID:6937191

  6. The experimental study on protective effects and mechanisms of chelating agents of catechols amino carboxylic acid for radiation injury induced by actimides(Th-234)

    International Nuclear Information System (INIS)

    The decorporative efficacy and antioxidative action of prompt and delayed consecutive administration of catecholicpolyaminopolycarboxylate ligands, 7601 and 9501 for radiothorium in mice were investigated. DTPA and Vitamin E were used as positive controls. The competitive abilities of 7601 and 9501 to mobilize the thorium with BSA were studied. Their inhibition effects on superoxide anionas radicals were measured with electron spin resonance. The results showed that 7601 and 9501 are able to effectively prevent the internal radiation injury induced radiothorium, attributing to their double functions of pronounced removal effectiveness and antioxidative action. Their protective effects were better than DTPA and Vitamin E. The mechanisms of protective effects of 7601 and 9501 for internal radiation injury was close related to competitive ability of chelating agent to chelate the thorium with BSA and oxygen free radical scavenging activities

  7. The lack of association between catechol-O-methyl-transferase Val108/158Met polymorphism and smoking in schizophrenia and alcohol dependence

    OpenAIRE

    Nikolac, Matea; Šagud, Marina; Nedić, Gordana; Nenadić Šviglin, Korona; Mihaljević Peleš, Alma; Uzun, Suzana; Vuskan Čusa, Bjanka; Kozumplik, Oliver; Živković, Maja; Mustapić, Maja; Jakovljević, Miro; Pavlović, Mladen; Muck-Šeler, Dorotea; Borovečki, Fran; Pivac, Nela

    2013-01-01

    The study elucidated the association between the COMT Val108/158Met polymorphism and smoking in patients with schizophrenia, patients with alcohol dependence and healthy control subjects. The stepwise logistic regression (odds ratio (OR)=1.56, 95% confidence interval (CI)=1.10–2.23, P=0.014) and the χ2 test (P=0.008) revealed that the COMT Val/Val genotype was significantly associated with smoking in healthy male subjects. Although the hypothesis of the study was that COMT Val108/158Met genot...

  8. No association between catechol-o-methyltransferase Val108/158Met polymorphism and schizophrenia or its clinical symptomatology in a Mexican population

    OpenAIRE

    Tovilla-Zárate, Carlos; Medellín, Beatriz Camarena; Fresán, Ana; López-Narváez, Lilia; Castro, Thelma Beatriz Gonzalez; Juárez Rojop, Isela; Ramírez-Bello, Julián; Genis, Alma; Nicolini, Humberto

    2012-01-01

    The gene coding for catecol-o-methyltransferase (COMT), participant in the metabolism of catecholamines, has long been implicated as a candidate gene for schizophrenia. We determined the relation of the COMT Val108/158Met polymorphism with schizophrenia or its symptomatology (negative, disorganized and psychotic dimension). We conducted a case–control study comprising 186 patients with schizophrenia and 247 controls. The diagnosis of schizophrenia was established using the DSM-IV criteria for...

  9. Polimorfismos dos genes do receptor de serotonina (5-HT2A) e da catecol-O-metiltransferase (COMT): fatores desencadeantes da fibromialgia? Serotonin receptor (5-HT 2A) and catechol-O-methyltransferase (COMT) gene polymorphisms: Triggers of fibromyalgia?

    OpenAIRE

    Josie Budag Matsuda; Flávia Regina Barbosa; Lucas Junqueira Fernandes Morel; Suzelei de Castro França; Sonia Marli Zingaretti; Lucienir Maria da Silva; Ana Maria Soares Pereira; Mozart Marins; Ana Lúcia Fachin

    2010-01-01

    INTRODUÇÃO: A fibromialgia é uma síndrome reumática caracterizada por dor difusa e crônica associada a fadiga, insônia, ansiedade, depressão, perda de memória e tontura. Embora os mecanismos fisiológicos que controlam a fibromialgia não tenham sido estabelecidos, fatores neuroendócrinos, genéticos ou moleculares podem estar envolvidos. OBJETIVO: O objetivo do presente estudo foi caracterizar os polimorfismos dos genes do receptor de serotonina (5-HT2A) e da catecolO-metiltransferase (COMT) em...

  10. Catechol-o-methyl transferase (COMT) val158met polymorphism and adolescent cortical development in patients with childhood-onset schizophrenia, their non-psychotic siblings, and healthy controls

    OpenAIRE

    Raznahan, Armin; Greenstein, Deanna; Lee, Yohan; Long, Robert; Clasen, Liv; Gochman, Pete; Addington, Anjene; GIEDD, JAY N.; Rapoport, Judith L.; Gogtay, Nitin

    2011-01-01

    Non-psychotic individuals at increased risk for schizophrenia show alterations in fronto-striatal dopamine signaling and cortical gray matter maturation reminiscent of those seen in schizophrenia. It remains unclear however if variations in dopamine signaling influence rates of structural cortical maturation in typically developing individuals, and whether such influences are disrupted in patients with schizophrenia and their non-psychotic siblings. We sought to address these issues by relati...

  11. OXIDATION AND ADSORPTION OF CATECHOL WITH POLYPHENOL OXIDASE-CELITE COUPLED SYSTEM IN AQUEOUS MEDIA%多酚氧化酶-硅藻土耦合系统选择性氧化/吸附邻苯二酚

    Institute of Scientific and Technical Information of China (English)

    刘璘; 施正策; 王权; 金江南; 樊云

    2003-01-01

    研究了多酚氧化酶-硅藻土耦合系统在苯甲醚共存条件下氧化邻苯二酚及产物吸附过程的特性.多酚氧化酶表现出对酚类物质的特异性催化作用,不受共存非酚类物质的影响;硅藻土与反应产物之间的特异性吸附作用有利于从溶液中分离邻苯二酚.耦合系统对酶促反应具有增强效应,多酚氧化酶在溶液中的相应半衰期增加2.4倍;当硅藻土/酶的质量比为6时,最大分离效率达到98.76 %.

  12. Inhibition of catechol-O-methyl transferase (COMT) by tolcapone restores reductions in microtubule-associated protein 2 (MAP2) and synaptophysin (SYP) following exposure of neuronal cells to neurotropic HIV.

    Science.gov (United States)

    Lee, Ting Ting; Chana, Gursharan; Gorry, Paul R; Ellett, Anne; Bousman, Chad A; Churchill, Melissa J; Gray, Lachlan R; Everall, Ian P

    2015-10-01

    This investigation aimed to assess whether inhibition of cathecol-O-methyl transferase (COMT) by tolcapone could provide neuroprotection against HIV-associated neurodegenerative effects. This study was conducted based on a previous work, which showed that a single nucleotide polymorphism (SNP) at position 158 (val158met) in COMT, resulted in 40 % lower COMT activity. Importantly, this reduction confers a protective effect against HIV-associated neurocognitive disorders (HAND), which have been linked to HIV-associated brain changes. SH-SY5Y-differentiated neurons were exposed to macrophage-propagated HIV (neurotropic MACS2-Br strain) in the presence or absence of tolcapone for 6 days. RNA was extracted, and qPCR was performed using Qiagen RT2 custom array consisting of genes for neuronal and synaptic integrity, COMT and pro-inflammatory markers. Immunofluorescence was conducted to validate the gene expression changes at the protein level. Our findings demonstrated that HIV significantly increased the messenger RNA (mRNA) expression of COMT while reducing the expression of microtubule-associated protein 2 (MAP2) (p = 0.0015) and synaptophysin (SYP) (p = 0.012) compared to control. A concomitant exposure of tolcapone ameliorated the perturbed expression of MAP2 (p = 0.009) and COMT (p = 0.024) associated with HIV. Immunofluorescence revealed a trend reduction of SYP and MAP2 with exposure to HIV and that concomitant exposure of tolcapone increased SYP (p = 0.016) compared to HIV alone. Our findings demonstrated in vitro that inhibition of COMT can ameliorate HIV-associated neurodegenerative changes that resulted in the decreased expression of the structural and synaptic components MAP2 and SYP. As HIV-associated dendritic and synaptic damage are contributors to HAND, inhibition of COMT may represent a potential strategy for attenuating or preventing some of the symptoms of HAND. PMID:26037113

  13. The effects of gender and Catechol O-Methyltransferase (COMT) Val108/158Met polymorphism on emotion regulation in Velo-Cardio-Facial Syndrome (22q11.2 Deletion Syndrome): a fMRI study

    OpenAIRE

    Coman, Ioana L.; Gnirke, Matthew H.; Middleton, Frank A.; Antshel, Kevin M.; Fremont, Wanda; Higgins, Anne Marie; Shprintzen, Robert J.; Kates, Wendy R.

    2010-01-01

    Velocardiofacial syndrome (VCFS) is caused by a micro-deletion of over 40 genes at the q11.2 locus of chromosome 22 and is a risk factor for the development of schizophrenia and other psychiatric disorders. COMT, one of the genes located in the deleted region, has been considered as a major candidate gene for genetic susceptibility in psychiatric diseases. Its functional polymorphism Val108/158Met has been shown to affect prefrontal function and working memory and has been associated with emo...

  14. Stabilization of COMT by experimental design approaches

    OpenAIRE

    Oliveira, Diana Margarida Tavares de

    2014-01-01

    Catechol-O-methyltransferase (COMT) is monomeric enzyme magnesium dependent that is involved in the inactivation of catechol substrates such as dopamine, epinephrine and norepinephrine. The COMT enzyme is present as two isoforms, a soluble isoform (SCOMT) that is found in the cytoplasm and a membrane-bound isoform (MBCOMT) which is present mainly in the rough endoplasmatic reticulum membrane. Both isoforms are extremely thermolabile and, except for catechol estrogens, which possess simi...

  15. Phenolic Compound Utilization by the Soft Rot Fungus Lecythophora hoffmannii

    OpenAIRE

    Bugos, Robert C.; Sutherland, John B.; Adler, John H.

    1988-01-01

    Nine phenolic compounds were metabolized by the soft rot fungus Lecythophora hoffmannii via protocatechuic acid and subsequently cleaved by protocatechuate 3,4-dioxygenase as determined by oxygen uptake, substrate depletion, and ring cleavage analysis. Catechol was metabolized by catechol 1,2-dioxygenase. Fungal utilization of these aromatic compounds may be important in the metabolism of wood decay products.

  16. Variable Effect during Polymerization

    Science.gov (United States)

    Lunsford, S. K.

    2005-01-01

    An experiment performing the polymerization of 3-methylthiophene(P-3MT) onto the conditions for the selective electrode to determine the catechol by using cyclic voltammetry was performed. The P-3MT formed under optimized conditions improved electrochemical reversibility, selectivity and reproducibility for the detection of the catechol.

  17. Multivalent anchored and crosslinked hyperbranched polyglycerol monolayers as antifouling coating for titanium oxide surfaces.

    Science.gov (United States)

    Wei, Qiang; Krysiak, Stefanie; Achazi, Katharina; Becherer, Tobias; Noeske, Paul-Ludwig Michael; Paulus, Florian; Liebe, Hendrik; Grunwald, Ingo; Dernedde, Jens; Hartwig, Andreas; Hugel, Thorsten; Haag, Rainer

    2014-10-01

    A set of new catecholic monolayer coatings was developed to improve the antifouling performance of TiO2 surfaces. To solve the problem of the weak charge-transfer interaction between a single catechol anchor and TiO2, multiple catechol groups were combined with hyperbranched polyglycerol (hPG) which is a distinct dendritic scaffold that exposes its multivalent anchor groups on the surface. Thus, multivalent catecholic hPGs can be easily prepared for surface modification. The immobilization of the compounds was monitored by quartz crystal microbalance with dissipation monitoring. Surface properties of the coatings were analyzed by water contact angle, X-ray photoelectron spectroscopy, and atomic force microscopy. The antifouling ability and stability were investigated by protein adsorption and cell adhesion. By increasing the number of catechol groups on the hPG scaffold, the stability and surface coverage could be significantly enhanced. Moreover, the inner-layer crosslinking of the coatings by grafting and initiating vinyl groups clearly improved their long-term stability. As a result, hPG with a catecholic functional degree of 10% (hPG-Cat10) and hPG with both catecholic and vinylic functional degree of 5% (hPG-Cat5-V5) were identified as the best catecholic hPGs to prepare bioinert and stable monolayer coatings on TiO2. PMID:25189471

  18. Biomimetic Mussel Adhesive Inspired Clickable Anchors Applied to the Functionalization of Fe3O4 Nanoparticles

    NARCIS (Netherlands)

    Goldmann, Anja S.; Schoedel, Christine; Walther, Andreas; Yuan, Jiayin; Loos, Katja; Mueller, Axel H. E.; Müller, Axel H.E.

    2010-01-01

    The functionalization of magnetite (Fe3O4) nanoparticles with dopamine-derived clickable biomimetic anchors is reported. Herein, an alkyne-modified catechol-derivative is employed as the anchor, as i) the catechol-functional anchor groups possess irreversible covalent binding affinity to Fe3O4 nanop

  19. Drug: D03241 [KEGG MEDICUS

    Lifescience Database Archive (English)

    Full Text Available D03241 Drug Nitecapone (INN) C12H11NO6 265.0586 265.2188 D03241.gif catechol O-methyltransferase ... (COMT ) inhibitor [HSA:1312] [KO:K00545] hsa00140(1312) S ... Enzymes Transferases catechol O-methyltransferase (COMT ) [HSA:1312] [KO:K00545] Nitecapone D03241 Nitecapo ...

  20. High-performance mussel-inspired adhesives of reduced complexity

    Science.gov (United States)

    Ahn, B. Kollbe; Das, Saurabh; Linstadt, Roscoe; Kaufman, Yair; Martinez-Rodriguez, Nadine R.; Mirshafian, Razieh; Kesselman, Ellina; Talmon, Yeshayahu; Lipshutz, Bruce H.; Israelachvili, Jacob N.; Waite, J. Herbert

    2015-10-01

    Despite the recent progress in and demand for wet adhesives, practical underwater adhesion remains limited or non-existent for diverse applications. Translation of mussel-inspired wet adhesion typically entails catechol functionalization of polymers and/or polyelectrolytes, and solution processing of many complex components and steps that require optimization and stabilization. Here we reduced the complexity of a wet adhesive primer to synthetic low-molecular-weight catecholic zwitterionic surfactants that show very strong adhesion (~50 mJ m-2) and retain the ability to coacervate. This catecholic zwitterion adheres to diverse surfaces and self-assembles into a molecularly smooth, thin (<4 nm) and strong glue layer. The catecholic zwitterion holds particular promise as an adhesive for nanofabrication. This study significantly simplifies bio-inspired themes for wet adhesion by combining catechol with hydrophobic and electrostatic functional groups in a small molecule.

  1. Relationship between Xinjiang Region Parkinson's Disease and the Interaction between Polymorphisms of Catechol-O-methyltransferase, Monoamine Oxidase B, Dopamine β-hydroxylase and Environmental Factors%COMT、MAOB、DBH基因多态性和环境因素交互作用与新疆地区帕金森病的关联性研究

    Institute of Scientific and Technical Information of China (English)

    宋秋霞; 李燕云; 张晓莺

    2015-01-01

    目的 探索基因-环境因素交互作用对新疆地区帕金森病(PD)发病风险的影响.方法 以新疆地区221例PD患者、229例自然对照者为研究对象,采用PCR-RFLP法检测儿茶酚胺氧位甲基转移酶(COMT)基因G1947A多态性、单胺氧化酶B(MAOB)基因内含子13G/A多态性、多巴胺β-羟化酶(DBH)基因5 TaqⅠ位点多态性基因分型,并收集其环境因素(吸烟史、饮酒史、重大精神创伤史、饮用井水史、农药接触史、化肥接触史)的暴露情况,在遗传平衡(H-WE)的基础上,采用多因子将维法(MDR)分析基因-环境交互效应.结果 ①在总样本,最佳交互模型为COMT-G 1947A多态性、重大精神创伤史、饮用井水史、化肥接触史联合作用模式,该模型的检验平衡准确度最大(65.58%)、交叉验证一致性结果为10/10(P=0.001 0).②按性别、民族、年龄进行分层分析,可见:a.在汉族群体中,最佳交互模型为重大精神创伤史、饮用井水史、化肥接触史联合作用模式,该模型的检验平衡准确度最大(76.68%)、交叉验证一致性结果为10/10(P=0.001 0);b.在年龄<60岁群体中,最佳交互模型为COMT-G 1947A多态性、化肥接触史联合作用模式,该模型的检验平衡准确度最大(69.00%)、交叉验证一致性结果为10/10(P=0.010 7).结论 研究发现基因-环境交互作用可能存在,是新疆地区PD的发病风险.

  2. Effect of pH and H2O2 dosage on catechol oxidation in nano-Fe3O4 catalyzing UV-Fenton and identification of reactive oxygen species

    DEFF Research Database (Denmark)

    Li, Weiguang; Wang, Yong; Angelidaki, Irini

    2014-01-01

    min and then increased, which was ascribed to the formation and destruction of some carboxylic acids. During the degradation, formic acid, acetic acid, oxalic acid, and maleic acid were detected. The values of H2O2 utilization efficiency at 240min near 1.30 in reactions with 11.80mM H2O2 under initial...

  3. A Preliminary Study of Expression of a New Catechol- 1,2-Dioxygenase Gene ( tfd C) from Plesiomanas in Arabidopsis thaliana%邻单胞菌邻苯二酚1,2-双加氧酶基因(tfdC)在拟南芥中表达的初步研究

    Institute of Scientific and Technical Information of China (English)

    王文东; 陈文峻; 罗如新; 蒯本科

    2002-01-01

    将从一株邻单胞菌中克隆到的一个新的邻苯二酚1,2-双加氧酶基因(tfd C)的起始密码子由GTG突变成ATG,并克隆到农杆菌双元载体pPZPY122中,利用农杆菌介导转化模式植物拟南芥,获得了转化植株经过PCR,PCR-Southern和southern dot blot方法检测证实,tfdC基因已经整合到拟南芥基因组中.邻苯二酚1,2-双加氧酶酶活性检测表明,转基因植株具有一定的酶活性,而未转化的植株则不具有酶活性。

  4. 假单胞菌ZL13邻苯二酚2,3-双加氧酶基因的克隆表达%Cloning of a new catechol 2,3-dioxygenase gene from Pseudomonas sp.ZL13 and its expression in the E.coli BL21

    Institute of Scientific and Technical Information of China (English)

    张鲁进; 杨谦; 李娟

    2010-01-01

    寻找新型高效石油降解菌,并研究其相关基因一直是石油降解领域的热点.本文以细菌Pseudomonas sp.ZL13的降解性质粒pZL-1的DNA为模板,通过PCR扩增的方法进行基因克隆,得到邻苯二酚2,3-双加氧酶基因.序列分析结果表明,该基因大小为924 bp,编码307个氨基酸;序列同源性比较结果显示,该基因与荧光假单胞菌(Pseudomortas fluorescens)和恶臭假单胞菌(Pseudomonas pudita)的基因序列的相似性较高,处于同一分支.将目的基因连接到pGEX-4T-2表达载体上,在E.coli BL21中成功表达,转化子具有原油降解能力.

  5. The catalytic role of uranyl in formation of polycatechol complexes

    Directory of Open Access Journals (Sweden)

    Halada Gary P

    2011-03-01

    Full Text Available Abstract To better understand the association of contaminant uranium with natural organic matter (NOM and the fate of uranium in ground water, spectroscopic studies of uranium complexation with catechol were conducted. Catechol provides a model for ubiquitous functional groups present in NOM. Liquid samples were analyzed using Raman, FTIR, and UV-Vis spectroscopy. Catechol was found to polymerize in presence of uranyl ions. Polymerization in presence of uranyl was compared to reactions in the presence of molybdate, another oxyion, and self polymerization of catechol at high pH. The effect of time and dissolved oxygen were also studied. It was found that oxygen was required for self-polymerization at elevated pH. The potential formation of phenoxy radicals as well as quinones was monitored. The benzene ring was found to be intact after polymerization. No evidence for formation of ether bonds was found, suggesting polymerization was due to formation of C-C bonds between catechol ligands. Uranyl was found to form outer sphere complexes with catechol at initial stages but over time (six months polycatechol complexes were formed and precipitated from solution (forming humic-like material while uranyl ions remained in solution. Our studies show that uranyl acts as a catalyst in catechol-polymerization.

  6. Partially Purification and Characterization of Polyphenol Oxidase of Quince

    OpenAIRE

    YAĞAR, Hülya; SAĞIROĞLU, Ayten

    2002-01-01

    Polyphenol oxidase (PPO, EC 1.14.18.1) was extracted from quince (Cydonia oblonga) by using 0.1 M phosphate buffer, pH 6.8. The polyphenol oxidase of quince was partially purified by (NH4)2SO4 and dialysis. Substrate specificity experiments were carried out with catechol, pyrogallol, L-DOPA, p-cresole and tyrosine. Catechol was the most suitable substrate compound for quince PPO. The Michaelis constants were 4.54 mM, 7.35mM and 17.8 mM for catechol, pyrogallol and L-DOPA, respective...

  7. Silk Fibroin Aqueous-Based Adhesives Inspired by Mussel Adhesive Proteins.

    Science.gov (United States)

    Burke, Kelly A; Roberts, Dane C; Kaplan, David L

    2016-01-11

    Silk fibroin from the domesticated silkworm Bombyx mori is a naturally occurring biopolymer with charged hydrophilic terminal regions that end-cap a hydrophobic core consisting of repeating sequences of glycine, alanine, and serine residues. Taking inspiration from mussels that produce proteins rich in L-3,4-dihydroxyphenylalanine (DOPA) to adhere to a variety of organic and inorganic surfaces, the silk fibroin was functionalized with catechol groups. Silk fibroin was selected for its high molecular weight, tunable mechanical and degradation properties, aqueous processability, and wide availability. The synthesis of catechol-functionalized silk fibroin polymers containing varying amounts of hydrophilic polyethylene glycol (PEG, 5000 g/mol) side chains was carried out to balance silk hydrophobicity with PEG hydrophilicity. The efficiency of the catechol functionalization reaction did not vary with PEG conjugation over the range studied, although tuning the amount of PEG conjugated was essential for aqueous solubility. Adhesive bonding and cell compatibility of the resulting materials were investigated, where it was found that incorporating as little as 6 wt % PEG prior to catechol functionalization resulted in complete aqueous solubility of the catechol conjugates and increased adhesive strength compared with silk lacking catechol functionalization. Furthermore, PEG-silk fibroin conjugates maintained their ability to form β-sheet secondary structures, which can be exploited to reduce swelling. Human mesenchymal stem cells (hMSCs) proliferated on the silks, regardless of PEG and catechol conjugation. These materials represent a protein-based approach to catechol-based adhesives, which we envision may find applicability as biodegradable adhesives and sealants. PMID:26674175

  8. Diversity in electrochemical oxidation of dihydroxybenzenes in the presence of 1-methylindole

    Indian Academy of Sciences (India)

    Davood Nematollahi; Vahid Hedayatfar

    2011-09-01

    Electrochemical oxidation of some catechol derivatives (1a-e) have been studied in water/acetonitrile solution containing 1-methylindole (3) as a nucleophile, using cyclic voltammetry and controlledpotential coulometry. An interesting diversity in the mechanisms has been observed in electrochemical oxidation of catechol derivatives (1a-e) in the presence of 3. In this work, we have proposed reaction schemes , and for oxidation of 1a-e in the presence of 3.

  9. エビ類ポリフェノールオキシダーゼの分布および性質

    OpenAIRE

    中川, 孝之; 牧之段, 保夫; 藤田, 眞夫

    1992-01-01

    The distribution and properties of polyphenol oxidase from shrimps Penaeus japonicus and P. monodon were investigated to increase our knowledge of the blackening of crustaceans. Enzyme activity toward catechol was detected in all tissues from both species. The hepatopancreas was found to have the highest activity of catechol oxidation, and the muscle had very low activity. The shrimp enzymes had high oxidative activity towards various diphenols. The enzymes in the hepatopancreas and epidermis...

  10. Preparation of Sticky Escherichia coli through Surface Display of an Adhesive Catecholamine Moiety

    OpenAIRE

    Park, Joseph P.; Choi, Min-Jung; Kim, Se Hun; Lee, Seung Hwan; Lee, Haeshin

    2014-01-01

    Mussels attach to virtually all types of inorganic and organic surfaces in aqueous environments, and catecholamines composed of 3,4-dihydroxy-l-phenylalanine (DOPA), lysine, and histidine in mussel adhesive proteins play a key role in the robust adhesion. DOPA is an unusual catecholic amino acid, and its side chain is called catechol. In this study, we displayed the adhesive moiety of DOPA-histidine on Escherichia coli surfaces using outer membrane protein W as an anchoring motif for the firs...

  11. Bioconversion of Biomass-Derived Phenols Catalyzed by Myceliophthora thermophila Laccase

    OpenAIRE

    Anastasia Zerva; Nikolaos Manos; Stamatina Vouyiouka; Paul Christakopoulos; Evangelos Topakas

    2016-01-01

    Biomass-derived phenols have recently arisen as an attractive alternative for building blocks to be used in synthetic applications, due to their widespread availability as an abundant renewable resource. In the present paper, commercial laccase from the thermophilic fungus Myceliophthora thermophila was used to bioconvert phenol monomers, namely catechol, pyrogallol and gallic acid in water. The resulting products from catechol and gallic acid were polymers that were partially characterized i...

  12. Prevention of thermal degradation of red currant juice anthocyanins by phenolic compounds addition

    OpenAIRE

    Kopjar, Mirela; Piližota, Vlasta; Šubarić, D.; Babić, J.

    2009-01-01

    The aim of this study was investigation of prevention of thermal degradation of the red currant juice anthocyanins by addition of different phenolic compounds (catechol, 4-methyl catechol, catechin, chlorogenic acid and gallic acid). Phenolic compounds were added in 50:1 and 100:1 copigment:pigment molar ratio. Red currant juice samples were heated at 30, 50, 70 and 90 °C for 1 hour. Thermal degradation of anthocyanins was investigated through determination of anthocyanin content and calculat...

  13. Short-Chain Alcohols Promote Accelerated Membrane Distention in a Dynamic Liposome Model of Exocytosis

    OpenAIRE

    Wittenberg, Nathan J.; Zheng, Leiliang; Winograd, Nicholas; Ewing, Andrew G.

    2008-01-01

    We have used amperometric measurements in a model system consisting of two liposomes connected with a membrane nanotube to monitor catechol release during artificial exocytosis and thereby to elucidate the effect of small-chain alcohols on this dynamic membrane process. To determine the rate of membrane shape change, catechol release during membrane distention was monitored amperometrically, and the presence of alcohols in the buffer was shown to accelerate the membrane distention process in ...

  14. Drug: D08369 [KEGG MEDICUS

    Lifescience Database Archive (English)

    Full Text Available D08369 Drug Polyphloroglucinol phosphate; Dealyd (TN) (C6H7O6P)x D08369.gif Antispasmodic ATC co ... de: A03AX12 catechol O-methyltransferase (COMT ) inhibitor [HSA:1312] [KO:K00545] hsa00140(1312) S ... Enzymes Transferases catechol O-methyltransferase (COMT ) [HSA:1312] [KO:K00545] Phloroglucinol [ATC:A03AX1 ...

  15. Drug: D01259 [KEGG MEDICUS

    Lifescience Database Archive (English)

    Full Text Available D01259 Drug Flopropione (JP16/INN); Ephtanon (TN) C9H10O4 182.0579 182.1733 D01259.gif Analgesic ... eutic category: 1249 catechol O-methyltransferase (COMT ) inhibitor [HSA:1312] [KO:K00545] hsa00140(1312) S ... Enzymes Transferases catechol O-methyltransferase (COMT ) [HSA:1312] [KO:K00545] Flopropione D01259 Floprop ...

  16. Drinking Green Tea Modestly Reduces Breast Cancer Risk12

    OpenAIRE

    Shrubsole, Martha J.; Lu, Wei; Chen, Zhi; Shu, Xiao Ou; Zheng, Ying; Dai, Qi; Cai, Qiuyin; Gu, Kai; Ruan, Zhi Xian; Gao, Yu-Tang; Zheng, Wei

    2009-01-01

    Green tea is a commonly consumed beverage in China. Epidemiological and animal data suggest tea and tea polyphenols may be preventive against various cancers, including breast cancer. Catechol-O-methyltransferase (COMT) catalyzes catechol estrogens and tea polyphenols. The COMT rs4680 AA genotype leads to lower COMT activity, which may affect the relationship between green tea consumption and breast cancer risk. We evaluated whether regular green tea consumption was associated with breast can...

  17. New metabolic pathway for degradation of 2-nitrobenzoate by Arthrobacter sp. SPG

    Directory of Open Access Journals (Sweden)

    Pankaj Kumar Arora

    2015-06-01

    Full Text Available Arthrobacter sp. SPG utilized 2-nitrobenzoate as its sole source of carbon and energy and degraded it with accumulation of stoichiometric amounts of nitrite ions. Salicylate and catechol were detected as metabolites of the 2-nitrobenzoate degradation using high performance liquid chromatography and gas chromatography-mass spectrometry. Enzyme activities for 2-nitrobenzoate-2-monooxygenase, salicylate hydroxylase, and catechol-1,2-dioxygenase were detected in the crude extracts of the 2-nitrobenzoate-induced cells of strain SPG. The 2-nitrobenzoate-monooxygenase activity resulted in formation of salicylate and nitrite from 2-nitrobenzoate whereas salicylate hydroxylase catalyzed the conversion of salicylate to catechol. The ring-cleaving enzyme, catechol-1,2-dioxygenase cleaved catechol to cis, cis-muconic acid. Cells of strain SPG were able to degrade 2-nitrobenzoate in sterile as well as non-sterile soil microcosms. The results of microcosm studies showed that strain SPG degraded more than 90% of 2-nitrobenzoate within 10-12 days. This study clearly shows that Arthrobacter sp. SPG degraded 2-nitrobenzoate via a new pathway with formation of salicylate and catechol as metabolites. Arthrobacter sp. SPG may be used for bioremediation of 2-nitrobenzoate-contaminated sites due to its ability to degrade 2-nitrobenzoate in soil.

  18. Covalent bonding of chloroanilines to humic constituents: Pathways, kinetics, and stability

    International Nuclear Information System (INIS)

    Covalent coupling to natural humic constituents comprises an important transformation pathway for anilinic pollutants in the environment. We systematically investigated the reactions of chlorine substituted anilines with catechol and syringic acid in horseradish peroxidase (HRP) catalyzed systems. It was demonstrated that although nucleophilic addition was the mechanism of covalent bonding to both catechol and syringic acid, chloroanilines coupled to the 2 humic constituents via slightly different pathways. 1,4-addition and 1,2-addition are involved to catechol and syringic acid, respectively. 1,4-addition showed empirical 2nd order kinetics and this pathway seemed to be more permanent than 1,2-addition. Stability experiments demonstrated that cross-coupling products with syringic acid could be easily released in acidic conditions. However, cross-coupling with catechol was relatively stable at similar conditions. Thus, the environmental behavior and bioavailability of the coupling products should be carefully assessed. -- Highlights: •Chloroanilines covalently coupled to humic constituents in HRP catalyzed processes, which facilitated their transformation. •MS technique was employed to analyze the coupling products and therefore elucidate the reaction pathways. •Chloroanilines couple to catechol and syringic acid via 1,4- and 1,2-nucleophilic addition pathways, respectively. •Cross-coupling products formed via 1,4-nucleophilic addition pathway were more stable than those via 1,2-addition pathway. -- Bound residues of chloroanilines formed via 1,2- and 1,4-nucleophilic addition pathways showed different stability

  19. Cultivar affects browning susceptibility of freshly cut star fruit slices

    Directory of Open Access Journals (Sweden)

    Teixeira Gustavo Henrique de Almeida

    2006-01-01

    Full Text Available Consumption of freshly-cut horticultural products has increased in the last few years. The principal restraint to using freshly-cut carambola is its susceptibility to tissue-browning, due to polyphenol oxidase-mediated oxidation of phenolic compounds present in the tissue. The current study investigated the susceptibility to browning of star fruit slices (Averrhoa carambola L. of seven genotypes (Hart, Golden Star, Taen-ma, Nota-10, Malásia, Arkin, and Fwang Tung. Cultivar susceptibility to browning as measured by luminosity (L* varied significantly among genotypes. Without catechol 0.05 M, little changes occurred on cut surface of any cultivars during 6 hour at 25degreesC, 67% RH. Addition of catechol led to rapid browning, which was more intense in cvs. Taen-ma, Fwang Tung, and Golden Star, with reduction in L* value of 28.60%, 27.68%, and 23.29%, respectively. Browning was more intense in the center of the slices, particularly when treated with catechol, indicating highest polyphenol oxidase (PPO concentration. Epidermal browning, even in absence of catechol, is a limitation to visual acceptability and indicates a necessity for its control during carambola processing. Care must be given to appropriate selection of cultivars for fresh-cut processing, since cultivar varied in browning susceptibility in the presence of catechol.

  20. Effect of humic constituents on the transformation of chlorinated phenols and anilines in the presence of oxidoreductive enzymes or birnessite

    Energy Technology Data Exchange (ETDEWEB)

    Park, J.W.; Dec, J.; Bollag, J.M. (Pennsylvania State Univ., University Park, PA (United States)); Kim, J.E. (Kyngpook National Univ., Taegu (Korea, Republic of). Dept. of Agricultural Chemistry)

    1999-06-15

    Chlorinated phenols and anilines are transformed and detoxified in soil through oxidative coupling reactions mediated by enzymes or metal oxides. The reactions may be influences by humic constituents, such as syringaldehyde or catechol, that originate from lignin decomposition and are also subject to oxidative coupling. In this study, the effect of humic constituents on xenobiotic transformation was evaluated in vitro based on the determination of unreacted chlorophenols and chloroanilines. In experiments with peroxidase, laccase, and birnessite, the transformation of most chlorophenols was considerably enhanced by the addition of syringaldehyde. Less enhancement was observed using 4-hydroxybenzoic acid, and the addition of catechol resulted in a reduction of most transformations. The opposite was observed in experiments with tyrosinase, in which case catechol caused considerable enhancement of chlorophenol transformation. The varying effect of catechol can be explained by different transformation mechanisms involving either o-quinone coupling or free radical coupling. Regardless of the agent used to mediate the reactions, chloroanilines seemed to undergo nucleophilic addition to quinone oligomers, which resulted from coupling of the humic constituents. Catechol, which readily forms quinones and quinone oligomers, was most efficient in enhancing these reactions.

  1. Iron and cobalt complexes of 4,4,9,9-tetramethyl-5,8-diazadodecane-2, 11-dione dioxime ligand: Synthesis, characterization and reactivity studies

    Indian Academy of Sciences (India)

    Oindrila Das; Sayanti Chatterjee; Tapan Kanti Paine

    2011-11-01

    Two oximate bridged dinuclear complexes [Co$^{\\text{II}}_{2}$ (HL)2](ClO4)2 (1) and [Fe$^{text{II}}_{2}$ (HL)2](ClO4)2 (2), and a biomimetic iron(III)-catecholate complex [FeIII(HL)(DBC)] (3) of a dioxime ligand (H2L = 4,4,9,9-tetramethyl-5,8-diazadodecane-2,11-dione dioxime and DBCH2 = 3,5-di-tert-butylcatechol) were synthesized and characterized. X-ray single-crystal structures of both the dinuclear complexes exhibit an out-of-plane oximate bridge where the six-membered M2(NO)2 ring adopt a boat conformation with the metal ions in a fivecoordinate distorted trigonal bipyramidal geometry. Complexes 1 and 2 react with dioxygen at ambient condition to form the corresponding hydroxo- or oxo-bridged dinuclear cobalt(III) or iron(III) complexes. On the other hand, the iron(III)-catecholate complex (3) activate dioxygen to undergo oxidative C-C bond cleavage of catechol. The selective formation of extradiol catechol cleavage products in the reaction of 3 with dioxygen mimics the functional aspect of extradiol-cleaving catechol dioxygenases. The flexibility of ligand backbone is proposed to control the dioxygen reactivity of metal complexes.

  2. Biomimetic Modeling of Copper Complexes: A Study of Enantioselective Catalytic Oxidation on D-(+-Catechin and L-(−-Epicatechin with Copper Complexes

    Directory of Open Access Journals (Sweden)

    Francesco G. Mutti

    2008-01-01

    Full Text Available The biomimetic catalytic oxidations of the dinuclear and trinuclear copper(II complexes versus two catechols, namely, D-(+-catechin and L-(−-epicatechin to give the corresponding quinones are reported. The unstable quinones were trapped by the nucleophilic reagent, 3-methyl-2-benzothiazolinone hydrazone (MBTH, and have been calculated the molar absorptivities of the different quinones. The catalytic efficiency is moderate, as inferred by kinetic constants, but the complexes exhibit significant enantio-differentiating ability towards the catechols, albeit for the dinuclear complexes, this enantio-differentiating ability is lower. In all cases, the preferred enantiomeric substrate is D-(+-catechin to respect the other catechol, because of the spatial disposition of this substrate.

  3. ESR spectra of the olive phenolics oleuropein and keracyanin in the solid state

    Energy Technology Data Exchange (ETDEWEB)

    Hunter, C.R. [Monash University, Clayton, VIC (Australia). Anatomy Department; Troup, G.J.; Hutton, D.R. [Monash University, Clayton, VIC (Australia). Physics Department; Hewitt, D.J. [Monash University, Clayton, VIC (Australia). Chemistry Department; Romani, A.; Mulinacci, N.; Vincieri, F.F. [Universita degli Studi, Firenze (Italy). Dipartimento di Scienze Farmaceutiche

    1998-12-31

    Full text: Olives and extra virgin olive oil, are known to be very rich in antioxidants, most of which are phenolics, such as oleuropein, a derivative of catechol: the `catechol` ring is separated, and effectively isolated electrically from the other (6-sided) ring. The main anthocyanin in olives in keracyanin (cyanidin-3-0-rutinoside). Solid samples of these two phenolics, and of catechol, were examined by ESR using a Varian E-12 spectrometer (x-band: {approx}9.1 GHz) at room temperature. All three samples gave single unstructured lines of {approx} 10g. width with g-vales close to 2. The presence of these free radical signal shows the antioxidant action of these phenolics, even in the solid state. We believe this is first observation of free radicals in olive phenolics

  4. The Structure of a Plant Tyrosinase from Walnut Leaves Reveals the Importance of "Substrate-Guiding Residues" for Enzymatic Specificity.

    Science.gov (United States)

    Bijelic, Aleksandar; Pretzler, Matthias; Molitor, Christian; Zekiri, Florime; Rompel, Annette

    2015-12-01

    Tyrosinases and catechol oxidases are members of the class of type III copper enzymes. While tyrosinases accept both mono- and o-diphenols as substrates, only the latter substrate is converted by catechol oxidases. Researchers have been working for decades to elucidate the monophenolase/diphenolase specificity on a structural level and have introduced an early hypothesis that states that the reason for the lack of monophenolase activity in catechol oxidases may be its structurally restricted active site. However, recent structural and biochemical studies of this enzyme class have raised doubts about this theory. Herein, the first crystal structure of a plant tyrosinase (from Juglans regia) is presented. The structure reveals that the distinction between mono- and diphenolase activity does not depend on the degree of restriction of the active site, and thus a more important role for amino acid residues located at the entrance to and in the second shell of the active site is proposed. PMID:26473311

  5. Noble metal catalyzed aqueous phase hydrogenation and hydrodeoxygenation of lignin-derived pyrolysis oil and related model compounds.

    Science.gov (United States)

    Mu, Wei; Ben, Haoxi; Du, Xiaotang; Zhang, Xiaodan; Hu, Fan; Liu, Wei; Ragauskas, Arthur J; Deng, Yulin

    2014-12-01

    Aqueous phase hydrodeoxygenation of lignin pyrolysis oil and related model compounds were investigated using four noble metals supported on activated carbon. The hydrodeoxygenation of guaiacol has three major reaction pathways and the demethylation reaction, mainly catalyzed by Pd, Pt and Rh, produces catechol as the products. The presence of catechol and guaiacol in the reaction is responsible for the coke formation and the catalysts deactivation. As expected, there was a significant decrease in the specific surface area of Pd, Pt and Rh catalysts during the catalytic reaction because of the coke deposition. In contrast, no catechol was produced from guaiacol when Ru was used so a completely hydrogenation was accomplished. The lignin pyrolysis oil upgrading with Pt and Ru catalysts further validated the reaction mechanism deduced from model compounds. Fully hydrogenated bio-oil was produced with Ru catalyst. PMID:25280108

  6. Capillary electrophoresis microchip coupled with on-line chemiluminescence detection

    International Nuclear Information System (INIS)

    In the present work, chemiluminescence detection was integrated with capillary electrophoresis microchip. The microchip was designed on the principle of flow-injection chemiluminescence system and capillary electrophoresis. It has three main channels, five reservoirs and a detection cell. As model samples, dopamine and catechol were separated and detected using a permanganate chemiluminescent system on the prepared microchip. The samples were electrokinetically injected into the double-T cross section, separated in the separation channel, and then oxidized by chemiluminescent reagent delivered by a home-made micropump to produce light in the detection cell. The electroosmotic flow could be smoothly coupled with the micropump flow. The detection limits for dopamine and catechol were 20.0 and 10.0 μM, respectively. Successful separation and detection of dopamine and catechol demonstrated the distinct advantages of integration of chemiluminescent detection on a microchip for rapid and sensitive analysis

  7. ESR spectra of the olive phenolics oleuropein and keracyanin in the solid state

    International Nuclear Information System (INIS)

    Full text: Olives and extra virgin olive oil, are known to be very rich in antioxidants, most of which are phenolics, such as oleuropein, a derivative of catechol: the 'catechol' ring is separated, and effectively isolated electrically from the other (6-sided) ring. The main anthocyanin in olives in keracyanin (cyanidin-3-0-rutinoside). Solid samples of these two phenolics, and of catechol, were examined by ESR using a Varian E-12 spectrometer (x-band: ∼9.1 GHz) at room temperature. All three samples gave single unstructured lines of ∼ 10g. width with g-vales close to 2. The presence of these free radical signal shows the antioxidant action of these phenolics, even in the solid state. We believe this is first observation of free radicals in olive phenolics

  8. Modulation of arachidonic acid metabolism by phenols: relation to positions of hydroxyl groups and peroxyl radical scavenging properties.

    Science.gov (United States)

    Alanko, J; Riutta, A; Mucha, I; Vapaatalo, H; Metsä-Ketelä, T

    1993-01-01

    We have shown earlier that catecholamines have opposite regulative effects on prostaglandin (PG)E2 and leukotriene (LT)B4 formation with a receptor-independent mechanism in human polymorphonuclear leukocytes (PMNs) and whole blood. To shed further light on the mechanisms involved and structure-action relationship, we tested the effects of phenols (catechol, hydroquinone, phenol, and resorcinol) on the synthesis of PGE2 and LTB4 in human A23187-stimulated PMNs. To study the mechanism of how phenols influence PGE2 and LTB4 synthesis, their peroxyl radical-scavenging properties were analyzed. In general, low concentrations of phenols stimulated (catechol > hydroquinone > phenol) and high concentrations inhibited (resorcinol > catechol > hydroquinone > phenol) PGE2 formation. Resorcinol was different from the other phenols: It did not stimulate PGE2 synthesis at all, but it was effective inhibitor at high concentrations. Phenols had only an inhibitory effect on LTB4 formation (catechol = hydroquinone > phenol > resorcinol). The order of both stochiometric factors and reactivities of phenols for scavenging peroxyl radicals was catechol > hydroquinone > resorcinol > phenol. According to these results, phenols having hydroxyl groups in ortho- or paraposition have the greatest stimulative effect on PGE2 synthesis, the highest inhibitory action on LTB4 synthesis, and are good antioxidants. Resorcinol, having hydroxyl groups in the metaposition, behaves differently. It neither stimulates PGE2 nor inhibits LTB4 formation, but it is the most potent inhibitor of PGE2 formation. In spite of resorcinol's two hydroxyl groups, it mimics as an antioxidant phenol more than catechol and hydroquinone. PMID:8384148

  9. Carbon-13 magnetic relaxation rates or iron (III) complexes of some biogenic amines and parent compounds in aqueous solutions

    International Nuclear Information System (INIS)

    Spin-lattice relaxation rates (R1) from naturally occuring C-13 F.T. N.M.R. spectra of some catecholamines and parent compounds with Iron(III) at pD = 4 were determined in order to elucidate the molecular mechanism underlying their association in aqueous solutions. Complexation was observed only for catecholic ligands. The R1 values were used to calculate iron-carbon scaled distances, and two complexation models were proposed where the catecholic function binds Fe(III) in the first and second coordination spheres respectively. The latter case was shown to be the consistent with the molecular geometries. (orig.)

  10. Studies on cesium uptake by phenolic resins

    International Nuclear Information System (INIS)

    The selective removal of cesium by phenolic ion-exchange resins from highly salted alkaline radioactive solutions was studied. The resins were synthesized by alkaline polycondensation of phenol, resorcinol, catechol, and resorcinol-catechol mixture with formaldehyde and characterized for their moisture regain, ion-exchange (H+ → Na+) capacity, and distribution coefficient (KD) for cesium. The effects of open and sealed curing of the polymers on their properties were studied. The effect of Na+, NaOH, and Cs+ concentration on the uptake of cesium by resorcinol-formaldehyde resin was investigated, in particular. The chemical, thermal, and radiation stabilities of the polymers were also studied

  11. Accumulation of rare earth elements by siderophore-forming Arthrobacter luteolus isolated from rare earth environment of Chavara, India

    Indian Academy of Sciences (India)

    E S Challaraj Emmanuel; T Ananthi; B Anandkumar; S Maruthamuthu

    2012-03-01

    In this study, Arthrobacter luteolus, isolated from rare earth environment of Chavara (Quilon district, Kerala, India), were found to produce catechol-type siderophores. The bacterial strain accumulated rare earth elements such as samarium and scandium. The siderophores may play a role in the accumulation of rare earth elements. Catecholate siderophore and low-molecular-weight organic acids were found to be present in experiments with Arthrobacter luteolus. The influence of siderophore on the accumulation of rare earth elements by bacteria has been extensively discussed.

  12. Evidence for the generation of active oxygen by isoniazid treatment of extracts of Mycobacterium tuberculosis H37Ra.

    OpenAIRE

    Shoeb, H A; Bowman, B U; Ottolenghi, A C; Merola, A J

    1985-01-01

    Crude extracts of Mycobacterium tuberculosis H37Ra, an isonicotinic acid hydrazide (isoniazid) (INH)-susceptible strain which has peroxidase activity, catalyzed the production of catechol from phenol in the presence of INH and H2O2 as shown by the development of the 444-nm absorption peak of oxidized catechol product. Extracts of the INH-resistant strain of M. tuberculosis H37Ra, which has no peroxidase, did not catalyze the reaction. The rate of development of the 444-nm peak increased propo...

  13. Reversible recruitment and emission of DO3A-derived lanthanide complexes at ligating molecular films on gold.

    Science.gov (United States)

    Lehr, Joshua; Bennett, Jamie; Tropiano, Manuel; Sørensen, Thomas J; Faulkner, Stephen; Beer, Paul D; Davis, Jason J

    2013-02-01

    The recruitment of DO3A-derived lanthanide complexes by ligation to isophthalic acid and catechol-modified gold surfaces, and their resulting sensitization, is reported herein. Predictably pH-dependent surface recruitment is associated with the expected fingerprint europium and terbium emission characteristics. The intensity of the lanthanide luminescence scales exponentially with spacer length, indicating a strong quenching interaction between the lanthanide and the gold surface. The switchable catechol oxidation state provides a means of electrochemically triggering the release of prior ligated complexes. PMID:23320931

  14. Sensitive electrochemical detection of the hydroxyl radical using enzyme-catalyzed redox cycling.

    Science.gov (United States)

    Tatsumi, Hirosuke; Osaku, Naoya

    2011-01-01

    Enzyme-catalyzed signal amplification was introduced to the electrochemical detection of the OH radical. In the presence of phenol as a trapping agent, glucose as a substrate, and pyrroloquinoline quinone-containing glucose dehydrogenase (PQQ-GDH) as a catalyst, the current signal for the trapping adducts (catechol and hydroquinone) produced by the hydroxylation of phenol could be amplified and detected sensitively. The limit of detection (S/N = 3) for catechol was 8 nM. The trapping efficiency of phenol was also estimated. PMID:22076331

  15. Studies on Laccase Activity in the Filamentous Fungus Trichoderma reesei

    OpenAIRE

    Sekme, Semra; Atacı, Neşe; Arısan, İnci

    2014-01-01

    Laccase have been mainly studied in wood rot fungal species of the basidiomycetes family especiallyin white rot fungi. Studies in other fungal families are largely lacking. This study has evaluated laccaseactivity fromTrichoderma reesei in catechol based medium. Results showed that laccase enzyme from T.reesei was active in acidic pH range and that optimum pH was 4.5. The optimum temperature oflaccase from T. reesei was also 270C. Laccase activity in medium containing 10 gL-1 catechol was 1.2...

  16. Biochemical, transcriptional and translational evidences of the phenol-meta-degradation pathway by the hyperthermophilic Sulfolobus solfataricus 98/2.

    Directory of Open Access Journals (Sweden)

    Alexia Comte

    Full Text Available Phenol is a widespread pollutant and a model molecule to study the biodegradation of monoaromatic compounds. After a first oxidation step leading to catechol in mesophilic and thermophilic microorganisms, two main routes have been identified depending on the cleavage of the aromatic ring: ortho involving a catechol 1,2 dioxygenase (C12D and meta involving a catechol 2,3 dioxygenase (C23D. Our work aimed at elucidating the phenol-degradation pathway in the hyperthermophilic archaea Sulfolobus solfataricus 98/2. For this purpose, the strain was cultivated in a fermentor under different substrate and oxygenation conditions. Indeed, reducing dissolved-oxygen concentration allowed slowing down phenol catabolism (specific growth and phenol-consumption rates dropped 55% and 39%, respectively and thus, evidencing intermediate accumulations in the broth. HPLC/Diode Array Detector and LC-MS analyses on culture samples at low dissolved-oxygen concentration (DOC  =  0.06 mg x L(-1 suggested, apart for catechol, the presence of 2-hydroxymuconic acid, 4-oxalocrotonate and 4-hydroxy-2-oxovalerate, three intermediates of the meta route. RT-PCR analysis on oxygenase-coding genes of S. solfataricus 98/2 showed that the gene coding for the C23D was expressed only on phenol. In 2D-DIGE/MALDI-TOF analysis, the C23D was found and identified only on phenol. This set of results allowed us concluding that S. solfataricus 98/2 degrade phenol through the meta route.

  17. Effect of binary combinations of selected toxic compounds on growth and fermentation of Kluyveromyces marxianus.

    Science.gov (United States)

    Oliva, Jose M; Ballesteros, Ignacio; Negro, M José; Manzanares, Paloma; Cabañas, Araceli; Ballesteros, Mercedes

    2004-01-01

    The inhibitory effects of various lignocellulose degradation products on glucose fermentation by the thermotolerant yeast Kluyveromyces marxianus were studied in batch cultures. The toxicity of the aromatic alcohol catechol and two aromatic aldehydes (4-hydroxybenzaldehyde and vanillin) was investigated in binary combinations. The aldehyde furfural that usually is present in relatively high concentration in hydrolyzates from pentose degradation was also tested. Experiments were conducted by combining agents at concentrations that individually caused 25% inhibition of growth. Compared to the relative toxicity of the individual compounds, combinations of furfural with catechol and 4-hydroxybenzaldehyde were additive (50% inhibition of growth). The other binary combinations assayed (catechol with 4-hydroxybenzaldehyde, and vanillin with catechol, furfural, or 4-hydroxybenzaldehyde) showed synergistic effect on toxicity and caused a 60-90% decrease in cell mass production. The presence of aldehydes in the fermentation medium strongly inhibited cell growth and ethanol production. Kluyveromyces marxianus reduces aldehydes to their corresponding alcohols to mitigate the toxicity of these compounds. The total reduction of aldehydes was needed to start ethanol production. Vanillin, in binary combination, was dramatically toxic and was the only compound for which inhibition could not be overcome by yeast strain assimilation, causing a 90% reduction in both cell growth and fermentation. PMID:15176873

  18. Dihydroxy-Benzenes as Corrosion Inhibitors for Aluminium Sheet in Alkali Solution

    International Nuclear Information System (INIS)

    Additions of dihydroxy-benzenes (such as catechol, hydeoquinione and resorcinol)as corrosion inhibitors decrease the corrosion of aluminium sheet (which is given in the market) in 0.1M-1.0M sodium hydroxide solutions. The decrease is dependent upon the concentration of the sodium hydroxide and that of the inhibitor. Inhibitive efficiency is resorcinol < catechol< hydroquinone< resorcinol+hydroquinone at a concentration of 0.005% (w/w) dihydroxy-benzenes, and catechol< hydroquinone< resorcinol< resorcinol+hydroquinone at 0.5%, whereas the efficiency of all three inhibitors reaches approximately 100% at a concentration of 2% inhibitors in 0.1M NaOH. No correlation appears to exist between the inhibitor efficiency and the dissociation constant (Pk values) of the inhibitor. It can be said that 0.5M concentration of sodium hydroxide is the fittest for reducing the aluminium sheet by hydroquinone and formation of catechol-aluminium complex ions in the sodium hydroxide solutions

  19. 4-Oxalocrotonate tautomerase, its homologue YwhB, and active vinylpyruvate hydratase : Synthesis and evaluation of 2-fluoro substrate analogues

    NARCIS (Netherlands)

    Johnson, William H; Wang, Susan C; Stanley, Thanuja M; Czerwinski, Robert M; Almrud, Jeffrey J; Poelarends, Gerrit J; Murzin, Alexey G; Whitman, Christian P

    2004-01-01

    A series of 2-fluoro-4-alkene and 2-fluoro-4-alkyne substrate analogues were synthesized and examined as potential inhibitors of three enzymes: 4-oxalocrotonate tautomerase (4-OT) and vinylpyruvate hydratase (VPH) from the catechol meta-fission pathway and a closely related 4-OT homologue found in B

  20. Guide On Analysis Of Dangerous And Harmful Object

    International Nuclear Information System (INIS)

    This book lists the dangerous and harmful object, which are Acetaldehyde, Acetic acid, Acetone, Acrolein, Aldrin Ammonia, Arsenic, Asphalt, Barium, Benzene, Benzyl chloride, Butane, Butylamine, Butyl mercaptan, Cadmium, Cadmium chloride, Cadmium nitrate, Cadmium sulfate, Calcium, Calcium carbonate, Calcium chloride, Calcium cyanamide, Calcium oxide, Captan, Carbon black, Carbon dioxide, Carbon disulfide, Catechol, Chlordane, Chlorine, Chlorine dioxide, Chlorine trifluoride and Chloroacetic acid.

  1. IMPROVED SELECTIVE ELECTROCATALYTIC OXIDATION OF PHENOLS BY TYROSINASE-BASED CARBON PASTE ELECTRODE BIOSENSOR

    Science.gov (United States)

    Tyrosinase-based carbon paste electrodes are evaluated with respect to the viscosity and polarity of the binder liquids. The electrodes constructed using a lower viscosity mineral oil yielded a greater response to phenol and catechol than those using a higher viscosity oil of s...

  2. TYROSINASE-BASED CARBON PASTE ELECTRODE BIOSENSOR FOR DETECTION OF PHENOLS: BINDER AND PRE-OXIDATION EFFECTS

    Science.gov (United States)

    Tyrosinase-based carbon paste electrodes are evaluated with respect to the viscosity and polarity of the binder liquids. The electrodes constructed using a lower viscosity mineral oil or paraffin wax oil yielded a greater response to phenol and catechol than those using the hi...

  3. Potential Metabolic Activation of a Representative C2-Alkylated Polycyclic Aromatic Hydrocarbon 6-Ethylchrysene Associated with the Deepwater Horizon Oil Spill in Human Hepatoma (HepG2) Cells

    Science.gov (United States)

    2016-01-01

    Exposure to polycyclic aromatic hydrocarbons (PAHs) is the major human health hazard associated with the Deepwater Horizon oil spill. C2-Chrysenes are representative PAHs present in crude oil and could contaminate the food chain. We describe the metabolism of a C2-chrysene regioisomer, 6-ethylchrysene (6-EC), in human HepG2 cells. The structures of the metabolites were identified by HPLC-UV-fluorescence detection and LC-MS/MS. 6-EC-tetraol isomers were identified as signature metabolites of the diol-epoxide pathway. O-Monomethyl-O-monosulfonated-6-EC-catechol, its monohydroxy products, and N-acetyl-l-cysteine(NAC)-6-EC-ortho-quinone were discovered as signature metabolites of the ortho-quinone pathway. Potential dual metabolic activation of 6-EC involving the formation of bis-electrophiles, i.e., a mono-diol-epoxide and a mono-ortho-quinone within the same structure, bis-diol-epoxides, and bis-ortho-quinones was observed as well. The identification of 6-EC-tetraol, O-monomethyl-O-monosulfonated-6-EC-catechol, its monohydroxy products, and NAC-6-EC-ortho-quinone supports potential metabolic activation of 6-EC by P450 and AKR enzymes followed by metabolic detoxification of the ortho-quinone through interception of its redox cycling capability by catechol-O-methyltransferase and sulfotransferase enzymes. The tetraols and catechol conjugates could be used as biomarkers of human exposure to 6-EC resulting from oil spills. PMID:27054409

  4. PHYTOCHEMICAL STUDIES OF THE GENUS ZINGIBER FROM FAMILY ZINGIBERACEAE

    Directory of Open Access Journals (Sweden)

    Kasarkar A. R.

    2011-02-01

    Full Text Available Phytochemical analysis of three Zingiber species (Zingiberaceae revealed presence of phenols and phenolic compounds, acicubin, cyanogenic glycosides, flavonoid and lignins leucoanthocyanis, catechol, tannins, quinone, naptho-quinones and coumarin are absence in all the species. The chemical compounds like syringin glycosides, saponin are doubtful in these species.

  5. A new process for the synthesis of naphthalene based tanning agent

    International Nuclear Information System (INIS)

    A new process developed for the preparation of naphthalene catechu tanning agent consisted of sulphonation of naphthalene, condensation with formaldehyde, combining with naturally occurring catechol, followed by neutralization of the reaction mixture. The product was then dried, analyzed and tested for application on wet blue leather which showed excellent tanning properties. (author)

  6. Amphiphilic antioxidants from "cashew nut shell liquid" (CNSL) waste.

    Science.gov (United States)

    Amorati, Riccardo; Attanasi, Orazio A; Favi, Gianfranco; Menichetti, Stefano; Pedulli, Gian Franco; Viglianisi, Caterina

    2011-03-01

    Hydrogenated cardanol and cardols, contained in industrial grade cardanol oil and obtained by distillation of the raw "cashew nut shell liquid" (CNSL), are easily transformed into efficient 4-thiaflavane antioxidants bearing a long alkyl chain on A ring and a catechol group on B ring. PMID:21240431

  7. Parkinson's Disease and Its Management: Part 3: Nondopaminergic and Nonpharmacological Treatment Options.

    Science.gov (United States)

    DeMaagd, George; Philip, Ashok

    2015-10-01

    This installment of a five-part series reviews the role of nondopaminergic pharmacotherapies and adjunctive options-such as monoamine oxidase type B inhibitors, catechol-O-methyltransferase inhibitors, and anticholinergic agents-in managing Parkinson's disease. Nonpharmacological treatments are also explored. PMID:26535023

  8. Psychiatric and cognitive symptoms in Huntington's disease are modified by polymorphisms in catecholamine regulating enzyme genes

    DEFF Research Database (Denmark)

    Vinther-Jensen, T; Nielsen, T T; Budtz-Jørgensen, E;

    2016-01-01

    -described cohort of Danish HD gene-expansion carriers. We show that cognitive impairment and psychiatric symptoms in HD are modified by polymorphisms in the monoamine oxidase A (MAOA) and catechol-O-methyltransferase (COMT) genes and by the 4p16.3 B haplotype. These results support the theory of dopamine imbalance...

  9. Oral Treatment with the NADPH Oxidase Antagonist Apocynin Mitigates Clinical and Pathological Features of Parkinsonism in the MPTP marmoset Model

    NARCIS (Netherlands)

    Philippens, Ingrid H. C. H. M.; Wubben, Jacqueline A.; Finsen, Bente; 't Hart, Bert A.

    2013-01-01

    This study evaluates the therapeutic efficacy of the NADPH oxidase inhibitor apocynin, isolated as principal bioactive component from the medicinal plant Picrorhiza kurroa, in a marmoset MPTP model of Parkinson's disease (PD). The methoxy-substituted catechol apocynin has a similar structure as homo

  10. Cyclodextrin-facilitated bioconversion of 17 beta-estradiol by a phenoloxidase from Mucuna pruriens cell cultures

    NARCIS (Netherlands)

    Woerdenbag, H.J.; Pras, N.; Frijlink, H.W.; Lerk, C.F.; Malingré, T.M.

    1990-01-01

    After complexation with beta-cyclodextrin, the phenolic steroid 17 beta-estradiol could be ortho-hydroxylated into a catechol, mainly 4-hydroxyestradiol, by a phenoloxidase from in vitro grown cells of Mucuna pruriens. By complexation with beta-cyclodextrin the solubility of the steroid increased fr

  11. Potential Metabolic Activation of a Representative C2-Alkylated Polycyclic Aromatic Hydrocarbon 6-Ethylchrysene Associated with the Deepwater Horizon Oil Spill in Human Hepatoma (HepG2) Cells.

    Science.gov (United States)

    Huang, Meng; Mesaros, Clementina; Zhang, Suhong; Blair, Ian A; Penning, Trevor M

    2016-06-20

    Exposure to polycyclic aromatic hydrocarbons (PAHs) is the major human health hazard associated with the Deepwater Horizon oil spill. C2-Chrysenes are representative PAHs present in crude oil and could contaminate the food chain. We describe the metabolism of a C2-chrysene regioisomer, 6-ethylchrysene (6-EC), in human HepG2 cells. The structures of the metabolites were identified by HPLC-UV-fluorescence detection and LC-MS/MS. 6-EC-tetraol isomers were identified as signature metabolites of the diol-epoxide pathway. O-Monomethyl-O-monosulfonated-6-EC-catechol, its monohydroxy products, and N-acetyl-l-cysteine(NAC)-6-EC-ortho-quinone were discovered as signature metabolites of the ortho-quinone pathway. Potential dual metabolic activation of 6-EC involving the formation of bis-electrophiles, i.e., a mono-diol-epoxide and a mono-ortho-quinone within the same structure, bis-diol-epoxides, and bis-ortho-quinones was observed as well. The identification of 6-EC-tetraol, O-monomethyl-O-monosulfonated-6-EC-catechol, its monohydroxy products, and NAC-6-EC-ortho-quinone supports potential metabolic activation of 6-EC by P450 and AKR enzymes followed by metabolic detoxification of the ortho-quinone through interception of its redox cycling capability by catechol-O-methyltransferase and sulfotransferase enzymes. The tetraols and catechol conjugates could be used as biomarkers of human exposure to 6-EC resulting from oil spills. PMID:27054409

  12. Environ: E00485 [KEGG MEDICUS

    Lifescience Database Archive (English)

    Full Text Available edelin [CPD:C08626], epi-friedelanol [CPD:C17123], Fried...a-Glucogallin [CPD:C01158], Catechol [CPD:C00090], Pyrogallol [CPD:C01108], Gallic acid [CPD:C01424], Succinic acid [CPD:C00042], Fri

  13. Using "Pseudomonas Putida xylE" Gene to Teach Molecular Cloning Techniques for Undergraduates

    Science.gov (United States)

    Dong, Xu; Xin, Yi; Ye, Li; Ma, Yufang

    2009-01-01

    We have developed and implemented a serial experiment in molecular cloning laboratory course for undergraduate students majored in biotechnology. "Pseudomonas putida xylE" gene, encoding catechol 2, 3-dioxygenase, was manipulated to learn molecular biology techniques. The integration of cloning, expression, and enzyme assay gave students a chance…

  14. EPR studies of chromium(V) intermediates generated via reduction of chromium(VI) by DOPA and related catecholamines

    DEFF Research Database (Denmark)

    Pattison, D I; Lay, P A; Davies, Michael Jonathan

    2000-01-01

    The reductions of K2Cr2O7 by catecholamines, DOPA, DOPA-beta,beta-d2, N-acetyl-DOPA, alpha-methyl-DOPA, dopamine, adrenaline, noradrenaline, catechol, 1,2-dihydroxybenzoic acid (DHBA), and 4-tert-butylcatechol (TBC), produce a number of Cr(V) electron paramagnetic resonance (EPR) signals. These...

  15. Intermediate and mechanism of hydroxylation of o-iodophenol by salicylate hydroxylase.

    Science.gov (United States)

    Suzuki, K; Gomi, T; Itagaki, E

    1991-05-01

    Salicylate hydroxylase [EC 1.14.13.1] from Pseudomonas putida catalyzes the hydroxylation of salicylate, and also o-aminophenol, o-nitrophenol, and o-halogenophenols, to catechol. The reactions with these o-substituted phenols comprise oxygenative deamination, denitration, and dehalogenation, respectively. The reaction stoichiometry, as to NADH oxidized, oxygen consumed, and catechol formed, is 2 : 1 : 1, respectively. The mechanisms for the deiodination and oxygenation of o-iodophenol were investigated in detail by the use of I(+)-trapping reagents such as DL-methionine, 2-chlorodimedone, and L-tyrosine. The addition of the traps did not change the molar ratio of catechol formed to NADH oxidized, nor iodinated traps produced were in the incubation mixture. The results suggest that I+ was not produced on the deiodination in the hydroxylation of o-iodophenol. On the other hand, L-ascorbate, L-epinephrine, and phenylhydrazine increased the molar ratio. o-Phenylenediamine decreased it, being converted to phenazine. This suggests that o-benzoquinone is formed in the oxidation of o-iodophenol as a nascent product. The quinone was detected spectrophotometrically by means of the stopped-flow method. Kinetic analysis of the reactions revealed that o-benzoquinone is reduced nonenzymatically to catechol by a second molecule of NADH. A mechanism of elimination for the ortho-substituted groups of substrate phenols by the enzyme is proposed and discussed. PMID:1917904

  16. Modification of Depression by COMT val[superscript 158]Met Polymorphism in Children Exposed to Early Severe Psychosocial Deprivation

    Science.gov (United States)

    Drury, Stacy S.; Theall, Katherine P.; Smyke, Anna T.; Keats, Bronya J. B.; Egger, Helen L.; Nelson, Charles A.; Fox, Nathan A.; Marshall, Peter J.; Zeanah, Charles H.

    2010-01-01

    Objective: To examine the impact of the catechol-O-methyltransferase (COMT) val[superscript 158]met allele on depressive symptoms in young children exposed to early severe social deprivation as a result of being raised in institutions. Methods: One hundred thirty six children from the Bucharest Early Intervention Project (BEIP) were randomized…

  17. Cerebrospinal fluid biomarkers of central catecholamine deficiency in Parkinson’s disease and other synucleinopathies

    OpenAIRE

    Goldstein, David S.; Holmes, Courtney; Sharabi, Yehonatan

    2012-01-01

    Central catecholamine deficiency characterizes α-synucleinopathies such as Parkinson’s disease. We hypothesized that cerebrospinal fluid levels of neuronal metabolites of catecholamines provide neurochemical biomarkers of these disorders. To test this hypothesis we measured cerebrospinal fluid levels of catechols including dopamine, norepinephrine and their main respective neuronal metabolites dihydroxyphenylacetic acid and dihydroxyphenylglycol in Parkinson’s disease and two other synucleino...

  18. Persistent pain after mastectomy with reconstruction.

    LENUS (Irish Health Repository)

    Hickey, Oonagh T

    2011-09-01

    To determine the prevalence of persistent postsurgical pain (PPSP) and its influence on functional status, and to examine associations between PPSP and single nucleotide polymorphisms of the catechol-O-methyltransferase (COMT) gene and the guanosine triphosphate cyclohydrolase 1 (GCH1) gene following mastectomy and reconstruction.

  19. COMT val(158)met genotype and smooth pursuit eye movements in schizophrenia

    DEFF Research Database (Denmark)

    Haraldsson, H Magnus; Ettinger, Ulrich; Magnusdottir, Brynja B;

    2009-01-01

    The association between the catechol-O-methyltransferase (COMT) val(158)met polymorphism (rs4680) and smooth pursuit eye movements (SPEM) was investigated in 110 schizophrenia patients and 96 controls. Patients had lower steady-state pursuit gain and made more frequent saccades than controls...

  20. DBH -1021C>T and COMT Val108/158Met genotype are not associated with the P300 ERP in an auditory oddball task

    NARCIS (Netherlands)

    Spronk, D.B.; Veth, C.P.M.; Arns, M.; Schofield, P.R.; Dobson-Stone, C.; Ramaekers, J.G.; Franke, B.; Bruijn, E.R. de; Verkes, R.J.

    2013-01-01

    OBJECTIVE: The amplitude and latency of the P300 may be associated by variations in dopaminergic genes. The current study was conducted to determine whether functional variants of the catechol-O-methyltransferase (COMT) and dopamine beta-hydroxylase (DBH) gene were associated with P300 amplitude and

  1. Association between Gene Polymorphisms and Pain Sensitivity Assessed in a Multi-Modal Multi-Tissue Human Experimental Model - An Explorative Study

    DEFF Research Database (Denmark)

    Nielsen, Lecia Møller; Olesen, Anne Estrup; Sato, Hiroe;

    2016-01-01

    The genetic influence on sensitivity to noxious stimuli (pain sensitivity) remains controversial and needs further investigation. In the present study, the possible influence of polymorphisms in three opioid receptor (OPRM, OPRD and OPRK) genes, and the catechol-O-methyltransferase (COMT) gene on...

  2. Child Exposure to Serious Life Events, COMT, and Aggression: Testing Differential Susceptibility Theory

    Science.gov (United States)

    Hygen, Beate Wold; Belsky, Jay; Stenseng, Frode; Lydersen, Stian; Guzey, Ismail Cuneyt; Wichstrøm, Lars

    2015-01-01

    Both genetic and environmental factors contribute to individual differences in aggression. Catechol-O-methyltransferase Val158Met (COMT), a common, functional polymorphism, has been implicated in aggression and aggression traits, as have childhood experiences of adversity. It is unknown whether these effects are additive or interactional and, in…

  3. Polymorphisms in Dopamine System Genes Are Associated with Individual Differences in Attention in Infancy

    Science.gov (United States)

    Holmboe, Karla; Nemoda, Zsofia; Fearon, R. M. Pasco; Csibra, Gergely; Sasvari-Szekely, Maria; Johnson, Mark H.

    2010-01-01

    Knowledge about the functional status of the frontal cortex in infancy is limited. This study investigated the effects of polymorphisms in four dopamine system genes on performance in a task developed to assess such functioning, the Freeze-Frame task, at 9 months of age. Polymorphisms in the catechol-O-methyltransferase ("COMT") and the dopamine…

  4. COMT Val158Met Genotype as a Risk Factor for Problem Behaviors in Youth

    Science.gov (United States)

    Albaugh, Matthew D.; Harder, Valerie S.; Althoff, Robert R.; Rettew, David C.; Ehli, Erik A.; Lengyel-Nelson, Timea; Davies, Gareth E.; Ayer, Lynsay; Sulman, Julie; Stanger, Catherine; Hudziak, James J.

    2010-01-01

    Objective: To test the association between the catechol-O-methyltransferase (COMT) Val158Met polymorphism and both aggressive behavior and attention problems in youth. We hypothesized that youth carrying a Met allele would have greater average aggressive behavior scores, and that youth exhibiting Val-homozygosity would have greater average…

  5. Sleep and COMT Polymorphism in ADHD Children: Preliminary Actigraphic Data

    Science.gov (United States)

    Gruber, Reut; Grizenko, Natalie; Schwartz, George; Amor, Leila Ben; Gauthier, Julie; de Guzman, Rosherrie; Joober, Ridha

    2006-01-01

    Objective: To examine whether COMT (catechol-O-methyltransferase) polymorphism modulates aspects of sleep in children diagnosed with attention-deficit/hyperactivity disorder (ADHD). Method: Nightly sleep actigraphic recordings during a double-blind, placebo-controlled, crossover clinical study (1 week of 0.5 mg/kg MPH; 1 week of placebo) were…

  6. Antioxidant properties and efficacies of synthesized alkyl caffeates, ferulates, and coumarates

    DEFF Research Database (Denmark)

    Sørensen, Ann-Dorit Moltke; Durand, Erwann; Laguerre, Mickaël;

    2014-01-01

    /w microemulsion using the conjugated autoxidizable triene (CAT) assay. All evaluated phenolipids had radical scavenging, reducing power, and metal chelating properties. Only caffeic acid and caffeates were able to form a complex with iron via their catechol group in the phenolic ring. In the o/w emulsion, the...

  7. Quantum mechanical calculation of aqueuous uranium complexes: carbonate, phosphate, organic and biomolecular species

    Directory of Open Access Journals (Sweden)

    Jha Prashant

    2009-08-01

    Full Text Available Abstract Background Quantum mechanical calculations were performed on a variety of uranium species representing U(VI, U(V, U(IV, U-carbonates, U-phosphates, U-oxalates, U-catecholates, U-phosphodiesters, U-phosphorylated N-acetyl-glucosamine (NAG, and U-2-Keto-3-doxyoctanoate (KDO with explicit solvation by H2O molecules. These models represent major U species in natural waters and complexes on bacterial surfaces. The model results are compared to observed EXAFS, IR, Raman and NMR spectra. Results Agreement between experiment and theory is acceptable in most cases, and the reasons for discrepancies are discussed. Calculated Gibbs free energies are used to constrain which configurations are most likely to be stable under circumneutral pH conditions. Reduction of U(VI to U(IV is examined for the U-carbonate and U-catechol complexes. Conclusion Results on the potential energy differences between U(V- and U(IV-carbonate complexes suggest that the cause of slower disproportionation in this system is electrostatic repulsion between UO2 [CO3]35- ions that must approach one another to form U(VI and U(IV rather than a change in thermodynamic stability. Calculations on U-catechol species are consistent with the observation that UO22+ can oxidize catechol and form quinone-like species. In addition, outer-sphere complexation is predicted to be the most stable for U-catechol interactions based on calculated energies and comparison to 13C NMR spectra. Outer-sphere complexes (i.e., ion pairs bridged by water molecules are predicted to be comparable in Gibbs free energy to inner-sphere complexes for a model carboxylic acid. Complexation of uranyl to phosphorus-containing groups in extracellular polymeric substances is predicted to favor phosphonate groups, such as that found in phosphorylated NAG, rather than phosphodiesters, such as those in nucleic acids.

  8. Assessment of the reactivity of selected isoflavones against proteins in comparison to quercetin.

    Science.gov (United States)

    Rawel, Harshadrai M; Ranters, Holger; Rohn, Sascha; Kroll, Jürgen

    2004-08-11

    Selected isoflavones (genistein, daidzein, formononetin, prunetin, biochanin A, and two synthetic isoflavones) were allowed to interact with soy and whey proteins. The reaction products were analyzed in terms of covalent binding at the nucleophilic side chains of proteins. Changes in molecular properties of the proteins derivatives were documented by SDS-PAGE, IEF, and SELDI-TOF-MS. The structural changes induced were studied using circular dichroism. The in vitro digestibility was assessed with trypsin. The results show that the occurrence of the catechol moiety, that is, the two adjacent (ortho) aromatic hydroxyl groups on ring B of the flavonoid structural skeleton appears to be prerequisite condition for covalent binding to proteins. The catechol moiety on ring A was less reactive. Its absence lead to a slight or no significant reaction, although noncovalent interactions may still be possible, even when lacking this structural element. A comparison of the data is also made with quercetin representing the flavonols. PMID:15291506

  9. Self-Healing Nanocomposite Hydrogel with Well-Controlled Dynamic Mechanics

    Science.gov (United States)

    Li, Qiaochu; Mishra, Sumeet; Chen, Pangkuan; Tracy, Joseph; Holten-Andersen, Niels

    Network dynamics is a crucial factor that determines the macroscopic self-healing rate and efficiency in polymeric hydrogel materials, yet its controllability is seldom studied in most reported self-healing hydrogel systems. Inspired by mussel's adhesion chemistry, we developed a novel approach to assemble inorganic nanoparticles and catechol-decorated PEG polymer into a hydrogel network. When utilized as reversible polymer-particle crosslinks, catechol-metal coordination bonds yield a unique gel network with dynamic mechanics controlled directly by interfacial crosslink structure. Taking advantage of this structure-property relationship at polymer-particle interfaces, we next designed a hierarchically structured hybrid gel with two distinct relaxation timescales. By tuning the relative contribution of the two hierarchical relaxation modes, we are able to finely control the gel's dynamic mechanical behavior from a viscoelastic fluid to a stiff solid, yet preserving its fast self-healing property without the need for external stimuli.

  10. Underwater contact adhesion and microarchitecture in polyelectrolyte complexes actuated by solvent exchange

    Science.gov (United States)

    Zhao, Qiang; Lee, Dong Woog; Ahn, B. Kollbe; Seo, Sungbaek; Kaufman, Yair; Israelachvili, Jacob N.; Waite, J. Herbert

    2016-04-01

    Polyelectrolyte complexation is critical to the formation and properties of many biological and polymeric materials, and is typically initiated by aqueous mixing followed by fluid-fluid phase separation, such as coacervation. Yet little to nothing is known about how coacervates evolve into intricate solid microarchitectures. Inspired by the chemical features of the cement proteins of the sandcastle worm, here we report a versatile and strong wet-contact microporous adhesive resulting from polyelectrolyte complexation triggered by solvent exchange. After premixing a catechol-functionalized weak polyanion with a polycation in dimethyl sulphoxide (DMSO), the solution was applied underwater to various substrates whereupon electrostatic complexation, phase inversion, and rapid setting were simultaneously actuated by water-DMSO solvent exchange. Spatial and temporal coordination of complexation, inversion and setting fostered rapid (~25 s) and robust underwater contact adhesion (Wad >= 2 J m-2) of complexed catecholic polyelectrolytes to all tested surfaces including plastics, glasses, metals and biological materials.

  11. Production of Protocatechuic Acid in Bacillus Thuringiensis ATCC33679

    Directory of Open Access Journals (Sweden)

    Bianca L. Garner

    2012-03-01

    Full Text Available Protocatechuic acid, or 3,4-dihydroxybenzoic acid, is produced by both soil and marine bacteria in the free form and as the iron binding component of the siderophore petrobactin. The soil bacterium, Bacillus thuringiensis kurstaki ATCC 33679, contains the asb operon, but does not produce petrobactin. Iron restriction resulted in diminished B. thuringiensis kurstaki ATCC 33679 growth and the production of catechol(s. The gene product responsible for protocatechuic acid (asbF and its receptor (fatB were expressed during stationary phase growth. Gene expression varied with growth temperature, with optimum levels occurring well below the Bacillus anthracis virulence temperature of 37 °C. Regulation of protocatechuic acid suggests a possible role for this compound during soil growth cycles.

  12. ADSORPTION OF PHENOLIC COMPOUNDS ONTO THE SPHERICAL MACROPOROUS ADSORBENT BASED ON UREA—FORMALDEHYDE CONDENSED POLYMER

    Institute of Scientific and Technical Information of China (English)

    XuMingcheng; XUMancai; 等

    2000-01-01

    Adsorption of phenol,catechol and resorcinol,which vary in their ability to interact with the adsorbent through hydrogen bond,were used to investigate the adsorption mechanistic interaction.The adsorption enthalpies of the above mentioned compound onto the adsorbent were calculated and thermodynamic analysis was carried out.The results showed the adsorbent with the lowest adsorption enthalpies for the sorbate such as catechol with intermolecular hydrogen bond also display the lowest adsorption affinity.On the other hand,the more of the groups available for hydrogen bond interaction,the higher of the adsorption affinity.These observations support the contention that phenol adsorption is driven predominantly by specific interaction of the solute with active sites on the surface of the adsorbent.

  13. Beyond brown: Polyphenol oxidases as enzymes of plant specialized metabolism

    Directory of Open Access Journals (Sweden)

    Michael L Sullivan

    2015-01-01

    Full Text Available Most cloned and/or characterized plant polyphenol oxidases (PPOs have catechol oxidase activity (i.e. they oxidize o-diphenols to o-quinones and are localized or predicted to be localized to plastids. As a class, they have broad substrate specificity and are associated with browning of produce and other plant materials. Because PPOs are often induced by wounding or pathogen attack, they are most generally believed to play important roles in plant defense responses. However, a few well-characterized PPOs appear to have very specific roles in the biosynthesis of specialized metabolites via both tyrosinase (monophenol oxidase and catechol oxidase activities. Here we detail a few examples of these and explore the possibility that there may be many more biosynthetic PPOs.

  14. Ultrastructural and Histochemical Characterization of the Zebra Mussel Adhesive Apparatus

    Science.gov (United States)

    Farsad, Nikrooz

    Since their accidental introduction into the Great Lakes in mid- to late-1980s, the freshwater zebra mussels, Dreissena polymorpha, have colonized most lakes and waterways across eastern North America. Their rapid spread is partly attributed to their ability to tenaciously attach to hard substrates via an adhesive apparatus called the byssus, resulting in serious environmental and economic impacts. A detailed ultrastructural study of the byssus revealed a 10 nm adhesive layer at the attachment interface. Distributions of the main adhesive amino acid, 3,4-dihydroxyphenylalanine (DOPA), and its oxidizing (cross-linking) enzyme, catechol oxidase, were determined histochemically. It was found that, upon aging, DOPA levels remained high in the portion of the byssus closest to the interface, consistent with an adhesive role. In contrast, reduced levels of DOPA corresponded well with high levels of catechol oxidase in the load-bearing component of the byssus, presumably forming cross-links and increasing the cohesive strength.

  15. A glassy carbon electrode modified with graphene and tyrosinase immobilized on platinum nanoparticles for sensing organophosphorus pesticides

    International Nuclear Information System (INIS)

    An amperometric biosensor is described for the detection of organophosphorus pesticides. It is based on the enzyme tyrosinase immobilized on platinum nanoparticles and the use of a glassy carbon electrode modified with graphene. Tyrosinase was immobilized on the electrode surface via electrostatic interaction between a monolayer of cysteamine and the enzyme. In the presence of catechol as a substrate, the pesticides chlorpyrifos, profenofos and malathion can be determined as a result of their inhibition of the enzyme which catalyzes the oxidation of catechol to o-quinone. Platinum nanoparticles and graphene effectively enhance the efficiency of the electrochemical reduction of o-quinone, thus improving sensitivity. Under optimum experimental conditions, the inhibition effect of the pesticides investigated is proportional to their concentrations in the lower ppb-range. The detection limits are 0.2, 0.8 and 3 ppb for chlorpyrifos, profenofos and malathion, respectively. The biosensor displays good repeatability and acceptable stability. (author)

  16. Hydro- and solvothermolysis of kraft lignin for maximizing production of monomeric aromatic chemicals.

    Science.gov (United States)

    Lee, Hong-shik; Jae, Jungho; Ha, Jeong-Myeong; Suh, Dong Jin

    2016-03-01

    The hydro-/solvothermolysis of kraft lignin using water and ethanol as a solvent were investigated in this study. The effect of the water-to-ethanol ratio on the yields of monomeric aromatic chemicals (MACs) and the kinetic behavior of MACs was studied in a series of batch experiments. The yields of MACs other than catechol increased as the ratio of ethanol increased, and the content of the total MACs in bio-crude oil (BCO) reached 35% when the ratio of ethanol was 100% at a reaction temperature of 300 °C. The formation of phenol, guaiacol, and alkylguaiacols was enhanced in ethanol, while the formation of catechol was dominant in water. The formation of more substituted MACs such as vanillin, acetoguaiacone, and homovanillic acid was not affected by the solvent. The role of reaction parameters on the yields of MACs was elucidated, and the main reaction pathways in water and in ethanol were proposed. PMID:26722814

  17. Application of a Pyroprobe-Deuterium NMR System: Deuterium Tracing and Mechanistic Study of Upgrading Process for Lignin Model Compounds

    Energy Technology Data Exchange (ETDEWEB)

    Ben, Haoxi; Jarvis, Mark W.; Nimlos, Mark R.; Gjersing, Erica L.; Sturgeon, Matthew R.; Foust, Thomas D.; Ragauskas, Arthur J.; Biddy, Mary J.

    2016-04-21

    In this study, a pyroprobe-deuterium (2H) NMR system has been used to identify isotopomer products formed during the deuteration and ring opening of lignin model compounds. Several common model compounds for lignin and its upgraded products, including guaiacol, syringol, toluene, p-xylene, phenol, catechol, cyclohexane, methylcyclohexane, and methylcyclopentane, have been examined for selective ring opening. Similar pathways for upgrading of toluene and p-xylene has been found, which will undergo hydrogenation, methyl group elimination, and ring opening process, and benzene, cyclohexane, and methylcyclohexane have been found as major intermediates before ring opening. Very interestingly, the 2H NMR analysis for the deuterium-traced ring opening of catechol on Ir/..gamma..-Al2O3 is almost identical to the ring opening process for phenol. The ring opening processes for guaiacol and syringol appeared to be very complicated, as expected. Benzene, phenol, toluene, cyclohexane, and methylcyclohexane have been determined to be the major products.

  18. Synthesis of novel guttiferone A derivatives: in-vitro evaluation toward Plasmodium falciparum, Trypanosoma brucei and Leishmania donovani.

    Science.gov (United States)

    Fromentin, Yann; Gaboriaud-Kolar, Nicolas; Lenta, Bruno Ndjakou; Wansi, Jean Duplex; Buisson, Didier; Mouray, Elisabeth; Grellier, Philippe; Loiseau, Philippe M; Lallemand, Marie-Christine; Michel, Sylvie

    2013-07-01

    The catechol pharmacomodulation of the natural product guttiferone A, isolated from the Symphonia globulifera tree, led to the semisynthesis of a collection of twenty derivatives. The ester and ether derivatives of guttiferone A were evaluated for their anti-plasmodial, trypanocidal and anti-leishmanial activities. Some compounds described below have shown potent antiparasitic activity against Plasmodium falciparum, Trypanosoma brucei and Leishmania donovani in a range from 1 to 5 μM. The evaluation of guttiferone A derivatives against VERO cells highlighted catechol modulations as an interesting tool to decrease the toxicity and keep the activity of this natural compound. The current study revealed new molecules as promising new antiparasitic drug candidates. PMID:23727538

  19. Oxidation of organic compounds in wastewater from the humid processing of coffee berries; Materiais a base de oxido de ferro para oxidacao de compostos presentes no efluente da despolpa do cafe

    Energy Technology Data Exchange (ETDEWEB)

    Goncalves, Maraisa; Guerreiro, Mario Cesar; Oliveira, Luiz Carlos Alves; Rocha, Cristian Luciana da [Universidade Federal de Lavras, MG (Brazil). Dept. de Quimica]. E-mail: guerrero@ufla.br

    2008-07-01

    Materials based on pure iron oxide and impregnated with niobia (Nb{sub 2}O{sub 5}) were prepared. Their catalytic activities were tested on the oxidation of compounds present in the wastewater from the processing of coffee berries. Particularly caffeine and catechol were tested. The oxidation reactions were carried out with the following systems: UV/H{sub 2}O{sub 2}; photo-Fenton and heterogeneous Fenton. All materials were characterized with X-ray diffraction, Moessbauer and infrared spectroscopy. Iron was mainly in the forms of goethite and maghemite. The oxidation kinetics were monitored by UV-vis and the oxidation products were monitored by mass spectrometry. The photo-Fenton reaction presented highest oxidation efficiency, removing 98% of all caffeine and catechol contents. (author)

  20. Mussel-inspired hydrophobic coatings for water-repellent textiles and oil removal.

    Science.gov (United States)

    García, Beatríz; Saiz-Poseu, Javier; Gras-Charles, Roser; Hernando, Jordi; Alibés, Ramon; Novio, Fernando; Sedó, Josep; Busqué, Félix; Ruiz-Molina, Daniel

    2014-10-22

    A series of catechol derivatives with a different number of linear alkyl chain substituents, and different length, have been shown to polymerize in the presence of aqueous ammonia and air, yielding hydrophobic coatings that present the ability to provide robust and efficient water repellency on weaved textiles, including hydrophilic cotton. The polymerization strategy presented exemplifies an alternative route to established melanin- and polydopamine-like functional coatings, affording designs in which all catechol (adhesive) moieties support specific functional side chains for maximization of the desired (hydrophobic) functionality. The coatings obtained proved effective in the transformation of polyester and cotton weaves, as well as filter paper, into reusable water-repellent, oil-absorbent materials capable of retaining roughly double their weight in model compounds (n-tetradecane and olive oil), as well as of separating water/oil mixtures by simple filtration. PMID:25272371

  1. Mechanically robust, negative-swelling, mussel-inspired tissue adhesives.

    Science.gov (United States)

    Barrett, Devin G; Bushnell, Grace G; Messersmith, Phillip B

    2013-05-01

    Most synthetic polymer hydrogel tissue adhesives and sealants swell considerably in physiologic conditions, which can result in mechanical weakening and adverse medical complications. This paper describes the synthesis and characterization of mechanically tough zero- or negative-swelling mussel-inspired surgical adhesives based on catechol-modified amphiphilic poly(propylene oxide)-poly(ethylene oxide) block copolymers. The formation, swelling, bulk mechanical, and tissue adhesive properties of the resulting thermosensitive gels were characterized. Catechol oxidation at or below room temperature rapidly resulted in a chemically cross-linked network, with subsequent warming to physiological temperature inducing a thermal hydrophobic transition in the PPO domains and providing a mechanism for volumetric reduction and mechanical toughening. The described approach can be easily adapted for other thermally sensitive block copolymers and cross-linking strategies, representing a general approach that can be employed to control swelling and enhance mechanical properties of polymer hydrogels used in a medical context. PMID:23184616

  2. Biotransformation of Hydroxylaminobenzene and Aminophenol by Pseudomonas putida 2NP8 Cells Grown in the Presence of 3-Nitrophenol

    OpenAIRE

    Zhao, Jian-Shen; Singh, Ajay; Huang, Xiao-Dong; Ward, Owen P.

    2000-01-01

    Biotransformation products of hydroxylaminobenzene and aminophenol produced by 3-nitrophenol-grown cells of Pseudomonas putida 2NP8, a strain grown on 2- and 3-nitrophenol, were characterized. Ammonia, 2-aminophenol, 4-aminophenol, 4-benzoquinone, N-acetyl-4-aminophenol, N-acetyl-2-aminophenol, 2-aminophenoxazine-3-one, 4-hydroquinone, and catechol were produced from hydroxylaminobenzene. Ammonia, N-acetyl-2-aminophenol, and 2-aminophenoxazine-3-one were produced from 2-aminophenol. All of th...

  3. Serotonergic Neurotoxic Thioether Metabolites of 3,4-Methylenedioxymethamphetamine (MDMA, “Ecstasy”): Synthesis, Isolation and Characterization of Diastereoisomers

    OpenAIRE

    Pizarro, Nieves; de la Torre, Rafael; Joglar, Jesús; Okumura, Noriko; Perfetti, Ximena; Lau, Serrine S.; Monks, Terrence J.

    2008-01-01

    3,4-Methylenedioxymethamphetamine (MDMA, ecstasy) is a synthetic recreational drug of abuse that produces long-term toxicity associated with the degeneration of serotonergic nerve terminals. In various animal models direct administration of MDMA into the brain fails to reproduce the serotonergic neurotoxicity, implying a requirement for the systemic metabolism and bioactivation of MDMA. Catechol-thioether metabolites of MDMA, formed via oxidation of 3,4-dihydroxymetamphetamine and 3,4-dihydro...

  4. Inhibition of 3,4-methylenedioxymethamphetamine (MDMA) metabolism leads to marked decrease in 3,4-dihydroxymethamphetamine (HHMA) formation but no change in serotonin neurotoxicity: Implications for mechanisms of neurotoxicity

    OpenAIRE

    Mueller, Melanie; Yuan, Jie; Adrian, Concepcion Maldonado; McCann, Una D.; Ricaurte, George A.

    2011-01-01

    3,4-Methylenedioxymethamphetamine (MDMA)’s O-demethylenated metabolite, 3,4-dihydroxymethamphetamine (HHMA), has been hypothesized to serve as a precursor for the formation of toxic catechol thioether metabolites (e.g. 5-N-acetylcystein-S-yl-HHMA) that mediate 3,4-methylenedioxymethamphetamine (MDMA) neurotoxicity. To further test this hypothesis, HHMA formation was blocked with dextromethorphan (DXM), which competitively inhibits cytochrome P450 enzyme-mediated O-demethylenation of MDMA to H...

  5. Electrochemical Oxidation of Rutin

    OpenAIRE

    Ghica, Mariana-Emilia; Brett, Ana Maria Oliveira

    2005-01-01

    An electrochemical investigation of rutin oxidation on a glassy carbon electrode was carried out using cyclic voltammetry, differential pulse voltammetry and square-wave voltammetry over a wide pH interval. The electrochemical oxidation is a complex process, which proceeds in a cascade mechanism, related with the 4-hydroxyl groups of the rutin molecule. The catechol 3prime,4prime-dihydroxyl group is the first to be oxidized by a two-electron - two-proton reversible oxidation reaction, followe...

  6. Peroxidase catalyzed conjugation of peptides, proteins and polysaccharides via endogenous and exogenous phenols.

    OpenAIRE

    Oudgenoeg, G.

    2004-01-01

    The research was directed towards peroxidase mediated cross-linking of proteins and polysaccharides. Two approaches were explored, cross-linking by use of ferulic acid (FA)oand cross-linking by use of catechol. Within each approach, first model studies were performed with small peptides, of which the findings were applied in subsequent studies with proteins. First, a kinetically controlled incubation that leads to covalently coupled adducts of the tripeptide Gly-Tyr-Gly (GYG) and FA, catalyze...

  7. Evaluation of the pharmacophoric motif of the caged Garcinia xanthones†

    OpenAIRE

    Chantarasriwong, Oraphin; Cho, Woo Cheal; Batova, Ayse; Chavasiri, Warinthorn; Moore, Curtis; Rheingold, Arnold L.; Theodorakis, Emmanuel A.

    2009-01-01

    The combination of unique structure and potent bioactivity exhibited by several family members of the caged Garcinia xanthones, led us to evaluate their pharmacophore. We have developed a Pd(0)-catalyzed method for the reverse prenylation of catechols that, together with a Claisen/Diels–Alder reaction cascade, provides rapid and efficient access to various caged analogues. Evaluation of the growth inhibitory activity of these compounds leads to the conclusion that the intact ABC ring system c...

  8. Direct isolation of flavonoids from plants using ultra-small anatase TiO2 nanoparticles

    OpenAIRE

    Kurepa, Jasmina; Nakabayashi, Ryo; Paunesku, Tatjana; Suzuki, Makoto; Saito, Kazuki; Woloschak, Gayle E.; Smalle, Jan A

    2013-01-01

    Surface functionalization of nanoparticles has become an important tool for the in vivo delivery of bioactive agents to their target sites. Here we describe the reverse strategy, nanoharvesting, in which nanoparticles are used as a tool to isolate and enrich bioactive compounds from living cells. Anatase TiO2 nanoparticles smaller than 20 nm form strong bonds with molecules carrying enediol and especially catechol groups. We show that these nanoparticles can enter plant cells, conjugate enedi...

  9. Structure and possible mechanism of the CcbJ methyltransferase from Streptomyces caelestis

    Czech Academy of Sciences Publication Activity Database

    Bauer, J.; Ondrovičová, G.; Najmanová, Lucie; Pevala, V.; Kameník, Zdeněk; Koštan, J.; Janata, Jiří; Kutejová, Eva

    2014-01-01

    Roč. 70, APR 2014 (2014), s. 943-957. ISSN 0907-4449 R&D Projects: GA MŠk(CZ) EE2.3.30.0003; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61388971 Keywords : CATECHOL-O-METHYLTRANSFERASE * SN2-LIKE TRANSITION-STATE * CRYSTAL-STRUCTURES Subject RIV: CE - Biochemistry Impact factor: 7.232, year: 2013

  10. Fe L-edge XAS Determination of Differential Orbital Covalency of Siderophore Model Compounds: Electronic Structure Contributions to High Stability Constants

    OpenAIRE

    Hocking, Rosalie K.; DeBeer George, Serena; Raymond, Kenneth N.; Hodgson, Keith O.; Hedman, Britt; Solomon, Edward I.

    2010-01-01

    Most bacteria and fungi produce low-molecular weight iron-chelators called siderophores. Although different siderophore structures have been characterized, the iron binding moieties often contain catecholate or hydroxamate groups. Siderophores function because of their extraordinarily high stability constants (KSTAB = 1030-1049) and selectivity for Fe(III), yet the origin of these high stability constants has been difficult to quantify experimentally. Herein, we utilise Fe L-edge X-ray absorp...

  11. BODIPY atropisomer interconversion, face discrimination, and superstructure appending.

    Science.gov (United States)

    Doulain, Pierre-Emmanuel; Goze, Christine; Bodio, Ewen; Richard, Philippe; Decréau, Richard A

    2016-03-25

    A strategy was developed to append sterically hindered apical pickets on both faces of the BODIPY platform to prevent stacking and aggregation. Ortho-substitution of both the meso-phenyl ring and the boron-bound catechol affords the right directionality to append pickets, achieve face discrimination, featuring two interconvertible atropisomers, and is reminiscent of the picket-fence strategy in porphyrins. PMID:26927530

  12. Effects of Active‐Site Modification and Quaternary Structure on the Regioselectivity of Catechol‐O‐Methyltransferase

    OpenAIRE

    Law, Brian J. C.; Bennett, Matthew R.; Thompson, Mark L; Levy, Colin; Shepherd, Sarah A; Leys, David; Micklefield, Jason

    2016-01-01

    Abstract Catechol‐O‐methyltransferase (COMT), an important therapeutic target in the treatment of Parkinson's disease, is also being developed for biocatalytic processes, including vanillin production, although lack of regioselectivity has precluded its more widespread application. By using structural and mechanistic information, regiocomplementary COMT variants were engineered that deliver either meta‐ or para‐methylated catechols. X‐ray crystallography further revealed how the active‐site r...

  13. Stabilising the lowest energy charge-separated state in a {metal chromophore – fullerene} assembly: a tuneable panchromatic absorbing donor–acceptor triad

    OpenAIRE

    Lebedeva, MA; Chamberlain, TW; Scattergood, PA; Delor, M; Sazanovich, IV; Davies, ES; Suyetin, M.; Besley, E; Schroder, M.; Weinstein, J; Khlobystov, AN

    2016-01-01

    Photoreduction of fullerene and the consequent stabilisation of a charge-separated state in a donor–acceptor assembly have been achieved, overcoming the common problem of a fullerene-based triplet state being an energy sink that prevents charge-separation. A route to incorporate a C60-fullerene electron acceptor moiety into a catecholate-Pt(II)-diimine photoactive dyad, which contains an unusually strong electron donor, 3,5-di-tert-butylcatecholate, has been developed. The synthetic methodolo...

  14. Carbon Paste Electrodes Made from Different Carbonaceous Materials: Application in the Study of Antioxidants

    OpenAIRE

    Constantin Apetrei; Maria Luz Rodriguez-Mendez; Jose Antonio De Saja; Irina Mirela Apetrei

    2011-01-01

    This work describes the sensing properties of carbon paste electrodes (CPEs) prepared from three different types of carbonaceous materials: graphite, carbon microspheres and carbon nanotubes. The electrochemical responses towards antioxidants including vanillic acid, catechol, gallic acid, L-ascorbic acid and L-glutathione have been analyzed and compared. It has been demonstrated that the electrodes based on carbon microspheres show the best performances in terms of kinetics and stability, wh...

  15. Strongly coupled ruthenium polypyridyl complexes for efficient electron injection in dye sensitized semiconductor nanoparticles

    International Nuclear Information System (INIS)

    Having understood the catecholate type of interactions with TiO2 in our recent studies, we have investigated the Ru(bpy)3-cat sensitized TiO3 nanoparticle system using femtosecond transient absorption spectroscopy. Electron injection has been confirmed by observing the bleach of the dye, cation radical of the dye and conduction band electron spectra spectra in the visible region. Electron injection has been observed to be 2 nanoparticles with similar interactions. (author)

  16. Scientific Validation of the Medicinal Efficacy of Tinospora cordifolia

    OpenAIRE

    Amita Mishra; Shashank Kumar; Pandey, Abhay K.

    2013-01-01

    Present communication reports the scientific evaluation of Tinospora cordifolia for its medicinal efficacy which includes phytochemical screening, antimicrobial, antioxidant, and anticancer activities of the plant. Secondary metabolites including anthraquinones, terpenoids, and saponins were present in many extracts in addition to phenolics. Total phenol contents in various extracts were found in the range of 8.75–52.50 catechol equivalent per gram (CE/g). In disc diffusion assays, polar extr...

  17. COMT Val158Met Genotype Selectively Alters Prefrontal [18F]Fallypride Displacement and Subjective Feelings of Stress in Response to a Psychosocial Stress Challenge

    OpenAIRE

    Dennis Hernaus; Dina Collip; Johan Lataster; Jenny Ceccarini; Gunther Kenis; Linda Booij; Jens Pruessner; Koen Van Laere; Ruud van Winkel; Jim van Os; Inez Myin-Germeys

    2013-01-01

    Catechol-O-methyltransferase (COMT) plays an essential role in degradation of extracellular dopamine in prefrontal regions of the brain. Although a polymorphism in this gene, COMT Val(158)Met, affects human behavior in response to stress little is known about its effect on dopaminergic activity associated with the human stress response, which may be of interest for stress-related psychiatric disorders such as psychosis. We aimed to investigate the effect of variations in COMT genotype on in v...

  18. Phenolic Profile of Asturian (Spain) Natural Cider

    OpenAIRE

    Rodríguez, Roberto; Picinelli, A.M. (Anna); Suárez, Belén

    2011-01-01

    The polyphenolic composition of natural ciders from the Asturian community (Spain), during 2 consecutive years, was analyzed by RP-HPLC and the photodiode-array detection system, without previous extraction (direct injection). A total of 16 phenolic compounds (catechol, tyrosol, protocatechuic acid, hydrocaffeic acid, chlorogenic acid, hydrocoumaric acid, ferulic acid, (-)-epicatechin, (+)-catechin, procyanidins B2 and B5, phloretin-2¢-xyloglucoside, phloridzin, hyperin, aviculari...

  19. Electroenzymatic Reactions With Oxygen on Laccase-Modified Electrodes in Anhydrous (Pure) Organic Solvent

    DEFF Research Database (Denmark)

    Yarapolov, A.; Shleev, S.; Zaitseva, E.;

    2007-01-01

    The electroenzymatic reactions of Trametes hirsuta laccase in the pure organic solvent dimethyl sulfoxide (DMSO) have been investigated within the framework for potential use as a catalytic reaction scheme for oxygen reduction. The bioelectrochemical characteristics of laccase were investigated in...... glassy carbon and graphite electrodes with adsorbed laccase. The influence of the time for drying the laccase solution at the electrode surface on the electroreduction of oxygen was studied. Investigating the electroenzymatic oxidation reaction of catechol and hydroquinone in DMSO reveals the formation...

  20. Processed coffee alleviates DSS-induced colitis in mice

    OpenAIRE

    Fiebich, Bernd L.; Amaya G. Vinuesa; Gonzalo Sanchez-Duffhues; Juan A. Collado; Thorsten Rose; Jörn Menthe; Eduardo Muñoz

    2013-01-01

    ABSTRACTBackground: Coffee is one of the most widely consumed beverages in the world and it has been demonstrated that it has important therapeutic activities not only because of its caffeine content but also owing to the presence of other biologically active small molecules such as chlorogenic acid, trigonelline and cyclopentadiones. However, chlorogenic acid is degraded into catechol, pyrogallol and hydroxyhydroquinone, which are thought to induce irritation of the gastric mucosa. To reduce...

  1. Effect of strong coupling on interfacial electron transfer dynamics in dye-sensitized TiO2 semiconductor nanoparticles

    Indian Academy of Sciences (India)

    Hirendra N Ghosh

    2007-03-01

    Dynamics of interfacial electron transfer (ET) in ruthenium polypyridyl complex [{bis-(2,2'-bpy)-(4-[2-(4'-methyl-[2,2']bipyridinyl-4-yl)-vinyl]-benzene-1,2-diol)}ruthenium(II) hexafluorophosphate] (Ru-cat) and 5,10,15-tris phenyl-20-(3,4-dihydroxy benzene) porphyrin (TPP-cat)-sensitized TiO2 nanoparticles have been investigated using femtosecond transient absorption spectroscopic detection in the visible and near-infrared region. We have observed that both Ru-cat and TPP-cat are coupled strongly with the TiO2 nanoparticles through their pendant catechol moieties. We have observed a single exponential and pulse-width limited (< 100 fs) electron injection from nonthermalized-excited states of Ru-complex. Here electron injection competes with the singlet-triplet manifold relaxation due to strong coupling of catecholate binding, which is a unique observation. Optical absorption measurements indicate that the catechol moiety interacts with TiO2 nanoparticles showing the characteristic pure catechol-TiO2 charge-transfer (CT) band in the visible region. Transient absorption studies on TPP-cat/TiO2 system exciting both the Soret band at 400 nm and the Q-band at 800 nm have been carried out to determine excitation wavelength-dependence on ET dynamics. The reaction channel for the electron-injection process has been found to be different for both the excitation wavelengths. Excitation at 800 nm, is found directly populate directly the excited CT state from where diffusion of electrons into the conduction band takes place. On the other hand, excitation at 400 nm light excites both the CT band of cat-TiO2 and also Soret band of TPP-cat.

  2. Human Aging Magnifies Genetic Effects on Executive Functioning and Working Memory

    OpenAIRE

    Nagel, Irene E.; Thomas Sander; Heekeren, Hauke R.; Lars Bäckman

    2008-01-01

    We demonstrate that common genetic polymorphisms contribute to the increasing heterogeneity of cognitive functioning in old age. We assess two common Val/Met polymorphisms, one affecting the Catechol-O-Methyltransferase (COMT) enzyme, which degrades dopamine (DA) in prefrontal cortex (PFC), and the other influencing the brain-derived neurotrophic factor (BDNF) protein. In two tasks (Wisconsin Card Sorting and spatial working memory), we find that effects of COMT genotype on cognitive performa...

  3. Impact of COMT Val158Met on executive functioning in the context of HIV and methamphetamine

    OpenAIRE

    Bousman, Chad A.; Cherner, Mariana; Glatt, Stephen J.; Atkinson, J. Hampton; Grant, Igor; Tsuang, Ming T.; Everall, Ian P.

    2010-01-01

    The catechol-O-methyltransferease (COMT) Val allele has been linked to executive dysfunction among healthy individuals. The nature of this relationship is unknown in the context of HIV infection and/or methamphetamine (METH) dependence, two conditions that can alter dopaminergic system functioning. We sought to determine if the putative relationship between COMT and executive dysfunction could be observed among individuals with and without HIV-infection and/or METH dependence, and to explore ...

  4. Effects of divorce on Dutch boys' and girls' externalizing behavior in Gene x Environment perspective: Diathesis stress or differential susceptibility in the Dutch Tracking Adolescents' Individual Lives Survey study?

    OpenAIRE

    Nederhof, Esther; Belsky, Jay; Ormel, Johan; Oldehinkel, Albertine J.

    2012-01-01

    The effects of divorce on children's behavioral development have proven to be quite varied across studies, and most developmental and family scholars today appreciate the great heterogeneity in divorce effects. Thus, this inquiry sought to determine whether select dopaminergic genes previously associated with externalizing behavior and/or found to moderate diverse environmental effects (dopamine receptors D2 and D4, catechol-O-methyltransferase) might moderate divorce effects on adolescent se...

  5. Variation in dopamine genes influences responsivity of the human reward system

    OpenAIRE

    Dreher, Jean-Claude; Kohn, Philip; Kolachana, Bhaskar; Weinberger, Daniel R.; Berman, Karen Faith

    2008-01-01

    In humans, dopamine neurotransmission is influenced by functional polymorphisms in the dopamine transporter (DAT1) and catechol-O-methyltransferase (COMT) genes. Here, we used event-related functional magnetic resonance imaging to directly investigate the neurofunctional effects of the Val158Met COMT and variable number of tandem repeat DAT1 polymorphisms on distinct components of the reward system in humans. The results revealed a main effect of COMT genotype in the ventral striatum and late...

  6. Lipase immobilized on polydopamine-coated magnetite nanoparticles for biodiesel production from soybean oil

    OpenAIRE

    Marcos F. C. Andrade; Andre L. A. Parussulo; Caterina G. C. M. Netto; Andrade, Leandro H.; Henrique E. Toma

    2016-01-01

    Lipase from Pseudomonas cepacia was covalently attached to magnetite nanoparticles coated with a thin polydopamine film, and employed in the enzymatic conversion of soybean oil into biodiesel, in the presence of methanol.  The proposed strategy explored the direct immobilization of the enzyme via Michael addition and aldolic condensation reactions at the catechol rings, with no need of using specific coupling agents. In addition, a larger amount of enzymes could be bound to the magnetic nanop...

  7. Metagenomics reveals diversity and abundance of meta-cleavage pathways in microbial communities from soil highly contaminated with jet fuel under air-sparging bioremediation

    Czech Academy of Sciences Publication Activity Database

    Brennerová, Mária; Josefiová, Jiřina; Brenner, Vladimír; Pieper, D. H.; Junca, H.

    2009-01-01

    Roč. 11, č. 9 (2009), s. 2216-2227. ISSN 1462-2912 R&D Projects: GA MŠk 1M06011; GA MŠk 2B06156 Institutional research plan: CEZ:AV0Z50200510 Keywords : DIOXYGENASE GENE DIVERSITY * CATECHOL 2,3-DIOXYGENASE * AROMATIC-COMPOUNDS Subject RIV: EE - Microbiology, Virology Impact factor: 4.909, year: 2009

  8. Xanthenedione Derivatives, New Promising Antioxidant and Acetylcholinesterase Inhibitor Agents

    OpenAIRE

    Seca, Ana M. L.; Stephanie B. Leal; Pinto, Diana C. G. A.; Maria Carmo Barreto; Artur M. S. Silva

    2014-01-01

    Natural and synthetic xanthone derivatives are well-known for their ability to act as antioxidants and/or enzyme inhibitors. This paper aims to present a successful synthetic methodology towards xanthenedione derivatives and the study of their aromatization to xanthones. Additionally their ability to reduce Fe(III), to scavenge DPPH radicals and to inhibit AChE was evaluated. The results demonstrated that xanthenedione derivative 5e, bearing a catechol unit, showed higher reduction capacity t...

  9. From the dual function lead AP2238 to AP2469, a multi-target-directed ligand for the treatment of Alzheimer's disease

    OpenAIRE

    Tarozzi, Andrea; Bartolini, Manuela; Piazzi, Lorna; Valgimigli, Luca; Amorati, Riccardo; Bolondi, Cecilia; Djemil, Alice; Mancini, Francesca; Andrisano, Vincenza; Rampa, Angela

    2014-01-01

    The development of drugs with different pharmacological properties appears to be an innovative therapeutic approach for Alzheimer's disease. In this article, we describe a simple structural modification of AP2238, a first dual function lead, in particular the introduction of the catechol moiety performed in order to search for multi-target ligands. The new compound AP2469 retains anti-acetylcholinesterase (AChE) and beta-site amyloid precursor protein cleaving enzyme (BACE)1 activities compar...

  10. Genetic and Vascular Modifiers of Age-Sensitive Cognitive Skills: Effects of COMT, BDNF, ApoE and Hypertension

    OpenAIRE

    Raz, Naftali; Rodrigue, Karen M.; Kennedy, Kristen M.; Land, Susan

    2009-01-01

    Cognitive phenotypes emerge from multiple genetic and environmental influences. Several single nucleotide polymorphisms have been linked to neural and cognitive variation in healthy adults. We examined contribution of three polymorphisms frequently associated with individual differences in cognition (Catechol-O-Methyl-Transferase Val158Met, Brain-Derived-Neurotrophic-Factor Val66Met, and Apolipoprotein E ɛ4) and a vascular risk factor (hypertension) as well as their interactions in a sample o...

  11. Isolation and characterization of Bacillus subtilis genes involved in siderophore biosynthesis: relationship between B. subtilis sfpo and Escherichia coli entD genes.

    OpenAIRE

    Grossman, T H; Tuckman, M; Ellestad, S; Osburne, M S

    1993-01-01

    In response to iron deprivation, Bacillus subtilis secretes a catecholic siderophore, 2,3-dihydroxybenzoyl glycine, which is similar to the precursor of the Escherichia coli siderophore enterobactin. We isolated two sets of B. subtilis DNA sequences that complemented the mutations of several E. coli siderophore-deficient (ent) mutants with defective enterobactin biosynthesis enzymes. One set contained DNA sequences that complemented only an entD mutation. The second set contained DNA sequence...

  12. Cloning of a Vibrio cholerae vibriobactin gene cluster: identification of genes required for early steps in siderophore biosynthesis.

    OpenAIRE

    Wyckoff, E E; Stoebner, J A; Reed, K E; Payne, S M

    1997-01-01

    Vibrio cholerae secretes the catechol siderophore vibriobactin in response to iron limitation. Vibriobactin is structurally similar to enterobactin, the siderophore produced by Escherichia coli, and both organisms produce 2,3-dihydroxybenzoic acid (DHBA) as an intermediate in siderophore biosynthesis. To isolate and characterize V. cholerae genes involved in vibriobactin biosynthesis, we constructed a genomic cosmid bank of V. cholerae DNA and isolated clones that complemented mutations in E....

  13. Apocynin: Molecular Aptitudes

    OpenAIRE

    R. Pawliczak; J. Stefanska

    2008-01-01

    Apocynin is a naturally occurring methoxy-substituted catechol, experimentally used as an inhibitor of NADPH-oxidase. It can decrease the production of superoxide (O2−) from activated neutrophils and macrophages while the ability of phagocytosis remains unaffected. The anti-inflammatory activity of apocynin has been demonstrated in a variety of cell and animal models of inflammation. Apocynin, after metabolic conversion, inhibits the assembly of NADPH-oxidase that is responsible for rea...

  14. Imaging genetics of schizophrenia

    OpenAIRE

    Meyer-Lindenberg, Andreas

    2010-01-01

    Recent years have seen an explosive growth of interest in the application of imaging genetics to understand neurogenetic mechanisms of schizophrenia. Imaging genetics applies structural and functional neuroimaging to study subjects carrying genetic risk variants that relate to a psychiatric disorder. We review selected aspects of this literature, starting with a widely studied candidate gene - the catechol-0-methyltransferase gene (COMT)- discussing other candidate genes in the dopaminergic s...

  15. Phase II metabolism of benzene.

    OpenAIRE

    Schrenk, D.; Orzechowski, A.; Schwarz, L R; Snyder, R.; Burchell, B; Ingelman-Sundberg, M; K. W. DE BOCK

    1996-01-01

    The hepatic metabolism of benzene is thought to be a prerequisite for its bony marrow toxicity. However, the complete pattern of benzene metabolites formed in the liver and their role in bone marrow toxicity are not fully understood. Therefore, benzene metabolism was studied in isolated rodent hepatocytes. Rat hepatocytes released benzene-1,2-dihydrodiol, hydroquinone (HQ), catechol (CT), phenol (PH), trans-trans-muconic acid, and a number of phase II metabolites such as PH sulfate and PH glu...

  16. Radical Scavenging and DNA Cleavage Inhibitory Activities of 2,3-Dihydroxybenzoyl Glycine Obtained from Bacillus subtilis

    Directory of Open Access Journals (Sweden)

    Jayesh J. Ahire

    2013-03-01

    Full Text Available A catecholate type of iron chelator (siderophore; 2,3-dihydroxybenzoyl glycine (DHBG was produced by Bacillus sp. under i ron stress conditions. Pure DHBG was subjected for DPPH ( α,α−Diphenyl−β− Picrylhydrazyl radical scavenging activity and radical induced DNA cleavage inhibition assay. In results, DHBG showed the highest radical scavenging effect and DNA cleavage inhibition activity when it was free from iron. This study revealed antioxidative potential of iron chelator DHBG; and its probable mechanism.

  17. Radical Scavenging and DNA Cleavage Inhibitory Activities of 2,3-Dihydroxybenzoyl Glycine Obtained from Bacillus subtilis

    OpenAIRE

    Ahire, Jayesh J.; Mahulikar, Pramod P.; Chaudhari, Bhushan L.

    2013-01-01

    A catecholate type of iron chelator (siderophore); 2,3-dihydroxybenzoyl glycine (DHBG) was produced by Bacillus sp. under i ron stress conditions. Pure DHBG was subjected for DPPH ( α,α−Diphenyl−β− Picrylhydrazyl ) radical scavenging activity and radical induced DNA cleavage inhibition assay. In results, DHBG showed the highest radical scavenging effect and DNA cleavage inhibition activity when it was free from iron. This study revealed antioxidative potential of iron chelator DHBG; and its p...

  18. Seamless Metallic Coating and Surface Adhesion of Self-Assembled Bioinspired Nanostructures Based on Di-(3,4-dihydroxy-l-phenylalanine) Peptide Motif

    OpenAIRE

    Fichman, Galit; Adler-Abramovich, Lihi; Manohar, Suresh; Mironi-Harpaz, Iris; Guterman, Tom; Seliktar, Dror; Messersmith, Phillip B.; Gazit, Ehud

    2014-01-01

    The noncoded aromatic 3,4-dihydroxy-l-phenylalanine (DOPA) amino acid has a pivotal role in the remarkable adhesive properties displayed by marine mussels. These properties have inspired the design of adhesive chemical entities through various synthetic approaches. DOPA-containing bioinspired polymers have a broad functional appeal beyond adhesion due to the diverse chemical interactions presented by the catechol moieties. Here, we harnessed the molecular self-assembly abilities of very short...

  19. New insights into the oxidation pathways of apomorphine

    OpenAIRE

    Garrido, Jorge; Delerue-Matos, Cristina; Borges, Fernanda; Macedo, Tice R. A.; Oliveira-Brett, A. M.

    2002-01-01

    A detailed study of the oxidative behaviour of apomorphine in aqueous media is reported. Resorting to the synthesis of apomorphine derivatives it was possible to identify all the anodic oxidation peaks of apomorphine, which are related to the oxidation of the catechol and tertiary amine groups. These findings were revealed to be important since they could lead to a better understanding of the biological interactions of apomorphine and gain insight into its metabolic pathways. Duri...

  20. Design of Ion-Exchange Resins Through EDTA and DTPA Modified Ligands

    Directory of Open Access Journals (Sweden)

    2014-07-01

    Catechol, resorcinol, and their admixtures with EDTA and DTPA moieties were converted into polymeric resins by alkaline polycondensation with formaldehyde. The resins were characterized by FTIR spectroscopy, elemental analysis, ion-exchange capacity, and distribution coefficient (D for heavy metal and radionuclide such as Cs and Sr. 137Cs and 90Sr constitutes a major source of heat in nuclear waste streams and in regards to recent nuclear event their remediation in complex solution – sea water - represent an important issue.

  1. Synthetic studies on the construction of 7-O-methylquercetin through regioselective protection and alkylation of quercetin

    Institute of Scientific and Technical Information of China (English)

    Nian Guang Li; Zhi Hao Shi; Yu Ping Tang; Jian Ping Yang; Tu Lin Lu; Feng Zhang; Yi Wen Huang; Zhen Jiang Wang; Jin Ao Duan

    2011-01-01

    Synthetic studies on the construction of 7-O-methylquercetin from quereetin in 36% yield in four steps is reported, this strategy relies on one hand on the selective protection of the catechol group with dichlorodiphenylmethane using dephenyl ether as a solvent, on the other hand, on the selective protection of the 3-hydroxyl group with benzyl bromide, these two different protecting groups can be removed under the same hydrogenation.

  2. COMT Genotype, Gender and Cognition in Community-Dwelling, Older Adults

    OpenAIRE

    O’Hara, Ruth; Miller, Elana; Liao, Chun-Ping; Way, Nate; Lin, Xiaoyan; Hallmayer, Joachim

    2006-01-01

    A common polymorphism (Val158Met) in the gene encoding for the catechol-O-methyltransferase (COMT) enzyme has been associated with differences in prefrontal cognitive function in schizophrenic patients and healthy adults. While several studies indicate that the Met allele is associated with better performance on measures of executive function, working memory and verbal fluency, results have been inconsistent. Furthermore, fewer studies have investigated this relationship in older adults, a gr...

  3. Bioactivation of myelotoxic xenobiotics by human neutrophil myeloperoxidase

    International Nuclear Information System (INIS)

    Many environmental pollutants and drugs are toxic to the bone marrow. Some of these xenobiotics may initiate toxicity after undergoing bioactivation to free radicals and/or other reactive electrophiles. Peroxidases are a group of enzymes that catalyze the one-electron oxidative bioactivation of a variety of xenobiotics in vitro. Myeloperoxidase (MPO) is a peroxidative enzyme found in very high concentration in the neutrophils of human bone marrow. In this study, human MPO was evaluated to determine its ability to catalyze the in vitro bioactivation of known bone marrow toxicants that contain the aromatic hydroxyl (Ar-OH), aromatic amine (Ar-N-R2), or heterocyclic tertiary amine (double-bond N-R) moieties. The formation of free radical metabolites during the MPO-catalyzed bioactivation of hydroquinone and catechol (benzene metabolites), mitoxantrone and ametantrone (antitumor drugs), and chlorpromazine and promazine (antipsychotic drugs) was demonstrated by EPR spectroscopy. The reactivity of the products formed during the MPO catalyzed bioactivation of [14C]hydroquinone and [14C]catechol was shown by their covalent binding to protein and DNA in vitro. The covalently binding metabolite in each case is postulated to be the quinone form of the xenobiotic. In addition, both GSH and NADH were oxidized by the reactive intermediate(s) formed during the MPO-catalyzed bioactivation of many of the bone marrow toxicants tested. It was also shown that p,p-biphenol stimulated the MPO catalyzed bioactivation of both hydroquinone and catechol, while p-cresol stimulated the MPO-catalyzed bioactivation of catechol

  4. Prevention of bedrest-induced physical deconditioning by daily dobutamine infusions. Implications for drug-induced physical conditioning.

    OpenAIRE

    Sullivan, M. J; P.F. Binkley; Unverferth, D V; Ren, J H; Boudoulas, H.; Bashore, T M; Merola, A J; Leier, C V

    1985-01-01

    The effects of intermittent infusions of dobutamine were studied in young normal male subjects during a period of bedrest deconditioning to determine whether this synthetic catechol affects physical conditioning processes in humans. 24 volunteers were placed at bedrest and randomized to daily 2-h treatments of saline infusions (control), dobutamine infusions, or maintenance exercise (control). Exercise, hemodynamic, and metabolic studies were performed at base line and at the termination of t...

  5. Adolescent Cannabis Use Increases Risk for Cocaine-Induced Paranoia

    OpenAIRE

    Kalayasiri, Rasmon; Gelernter, Joel; Farrer, Lindsay; Weiss, Roger; Brady, Kathleen; Gueorguieva, Ralitza; Kranzler, Henry R.; Malison, Robert T.

    2009-01-01

    Cannabis can produce and/or exacerbate psychotic symptoms in vulnerable individuals. Early exposure to cannabis, particularly in combination with genetic factors, increases the risk of a subsequent, primary, psychotic disorder. Because paranoia is a common feature of stimulant abuse and cocaine dependent individuals frequently endorse a history of cannabis abuse, we examined whether early cannabis exposure, in conjunction with polymorphic variation in the catechol-O-methyl transferase gene (C...

  6. Steady-state electrochemical determination of lipidic nanotube diameter utilizing an artificial cell model

    OpenAIRE

    Adams, Kelly L.; Engelbrektsson, Johan; Voinova, Marina; Zhang, Bo; Eves, Daniel J.; Karlsson, Roger; Heien, Michael L.; Cans, Ann-Sofie; Ewing, Andrew G.

    2010-01-01

    By exploiting the capabilities of steady-state electrochemical measurements, we have measured the inner diameter of a lipid nanotube using Fick's first law of diffusion in conjunction with an imposed linear concentration gradient of electroactive molecules over the length of the nanotube. Fick's law has been used in this way to provide a direct relationship between the nanotube diameter and the measurable experimental parameters Δi (change in current) and nanotube length. Catechol was used to...

  7. Genetic association between the COMT genotype and urinary levels of tea polyphenols and their metabolites among daily green tea drinkers

    OpenAIRE

    Inoue-Choi, Maki; Yuan, Jian-Min; Yang, Chung S.; Van Den Berg, David J.; Lee, Mao-Jung; Gao, Yu-Tang; Yu, Mimi C.

    2010-01-01

    Available in vitro and animal studies have shown cancer protective effects of tea polyphenols. Recent study suggests a greater protective effect of green tea intake on breast cancer risk among women possessing the low-activity associated genotype of the catechol-O-methyltransferase (COMT), which may modulate the metabolism and excretion of tea polyphenols through urine. To determine the effect of COMT genotype on urinary excretion of tea polyphenol metabolites of daily green tea drinkers, a c...

  8. Predicted formation constants using the unified theory of metal ion complexation

    International Nuclear Information System (INIS)

    Formation constants are listed for standard conditions, i.e., 298.15K (250C), 105 Pa, and zero ionic strength for a number of species containing selected elements (Am, Cs, Np, Pa, Pb, Pd, Pu, Ra, Sn, Sr, Tc, Th, U) and ligands (hydroxide, fluoride, chloride, bromide, iodide, iodate, sulphate, ammonia, nitrate, hydrogen phosphate, dihydrogen phosphate, carbonate, bicarbonate, oxalate, formate, thiocyanate, acetate, benzoate, catecholate, ethylenediamine, glycinate, glycollate and phenolate) that have been considered important for nuclear technology. 16 refs

  9. Observed positive parenting behaviors and youth genotype: Evidence for gene–environment correlations and moderation by parent personality traits

    OpenAIRE

    Oppenheimer, Caroline W.; Hankin, Benjamin L.; Jenness, Jessica L.; Young, Jami F.; Smolen, Andrew

    2013-01-01

    Gene–environment correlations (rGE) have been demonstrated in behavioral genetic studies, but rGE have proven elusive in molecular genetic research. Significant gene–environment correlations may be difficult to detect because potential moderators could reduce correlations between measured genetic variants and the environment. Molecular genetic studies investigating moderated rGE are lacking. This study examined associations between child catechol-O-methyltransferase genotype and aspects of po...

  10. Human CYP2E1-dependent and human sulfotransferase 1A1-modulated induction of micronuclei by benzene and its hydroxylated metabolites in Chinese hamster V79-derived cells.

    Science.gov (United States)

    Jiang, Hao; Lai, Yanmei; Hu, Keqi; Wei, Qinzhi; Liu, Yungang

    2014-12-01

    Benzene is a ubiquitous environmental pollutant and a confirmed human carcinogen, which requires metabolic activation, primarily by CYP2E1, for most of its biological actions. Chromosome damages in benzene-exposed workers and rodents have been observed, and in their urine sulfo- and glucuronide-conjugates of phenol and hydroquinone were present. Yet, direct evidence for human CYP2E1-activated mutagenicity of benzene and the exact significance of phase II metabolism for inactivating benzene metabolites are still missing. In the present study, benzene and its oxidized metabolites (phenol, hydroquinone, catechol, 1,2,4-trihydroxybenzene and 1,4-benzoquinone) were investigated for induction of micronuclei in a V79-derived cell line genetically engineered for expression of both human CYP2E1 and human sulfotransferase (SULT) 1A1 (indicated by active micronuclei induction by 1-hydroxymethylpyrene). The results demonstrated concentration-dependent induction of micronuclei by benzene and phenol, though with lower potency or efficacy than the other metabolites. Inhibition of CYP2E1 by 1-aminobenzotriazole did not change the effect of benzoquinone, but completely abolished that of benzene and phenol, and attenuated that of the other compounds. Moreover, inhibition of SULT1A1 by pentachlorophenol potentiated the effects of benzene, hydroquinone, catechol and trihydroxybenzene. Ascorbic acid, a reducing and free radical-scavenging agent, significantly lowered the effects of hydroquinone, catechol, trihydroxybenzene as well as N-nitrosodimethylamine (a known CYP2E1-dependent promutagen), with that of benzoquinone unaffected. These results suggest that in addition to activating benzene and phenol, human CYP2E1 may further convert hydroquinone, catechol and trihydroxybenzene to more genotoxic metabolites, and sulfo-conjugation of the multi-hydroxylated metabolites of benzene by human SULT1A1 may represent an important detoxifying pathway. PMID:25771868

  11. Production of L-dihydroxyphenylalanine in Escherichia coli with the tyrosine phenol-lyase gene cloned from Erwinia herbicola.

    OpenAIRE

    Foor, F; Morin, N.; Bostian, K A

    1993-01-01

    The gene (tutA) encoding tyrosine phenol-lyase from Erwinia herbicola was cloned into Escherichia coli, and fusions to the lac and tac promoters were constructed. The enzyme was expressed at high levels in E. coli in the presence of isopropyl-beta-D-thiogalactopyranoside or lactose as an inducer. L-Dihydroxyphenylalanine was synthesized in high yield from catechol, pyruvate, and ammonia by induced cells.

  12. Serotonin and Dopamine Gene Variation and Theory of Mind Decoding Accuracy in Major Depression: A Preliminary Investigation

    OpenAIRE

    Zahavi, Arielle Y.; Sabbagh, Mark A.; Dustin Washburn; Raegan Mazurka; R. Michael Bagby; John Strauss; Kennedy, James L.; Arun Ravindran; Harkness, Kate L.

    2016-01-01

    Theory of mind-the ability to decode and reason about others' mental states-is a universal human skill and forms the basis of social cognition. Theory of mind accuracy is impaired in clinical conditions evidencing social impairment, including major depressive disorder. The current study is a preliminary investigation of the association of polymorphisms of the serotonin transporter (SLC6A4), dopamine transporter (DAT1), dopamine receptor D4 (DRD4), and catechol-O-methyl transferase (COMT) gene...

  13. Epistatic interaction between COMT and DAT1 genes on eating behavior: A pilot study

    OpenAIRE

    Hersrud, Samantha L.; Stoltenberg, Scott F.

    2009-01-01

    Problems related to food and weight in women may be influenced by the (DA) dopamine system. Catechol-o-methyl transferase (COMT) and the dopamine transporter (DAT) exert control on concentrations of extracellular DA. High and low functioning alleles of the COMT Val158Met and DAT1 3′ UTR VNTR polymorphisms have been identified, and their associations with reward and cognition suggest a role in the modulation of eating behavior. A sample of undergraduate college women (N=71) was characterized f...

  14. NC-03POLYMORPHISMS IN THE COMT, BDNF AND DTNBP1 GENES AND COGNITIVE FUNCTIONS IN PATIENTS WITH BRAIN TUMORS

    OpenAIRE

    Correa, Denise; Satagopan, Jaya; Baser, Raymond; Cheung, Kenneth; DeAngelis, Lisa; Orlow, Irene

    2014-01-01

    BACKGROUND: Cognitive dysfunction is prevalen among brain tumor patients treated with radiotherapy (RT) and chemotherapy (CT). However, little is known about genetic risk factors that may moderate their vulnerability for developing cognitive impairment. In this study, we examined the association of single nucleotide polymorphisms (SNPs) in three genes, Catechol-O-Methyl-Transferase (COMT), Brain-Derived-Neurotrophic-Factor (BDNF), and dystrobrevin binding protein 1 (DTNBP1), and cognitive fun...

  15. Biosynthetic Analysis of the Petrobactin Siderophore Pathway from Bacillus anthracis▿

    OpenAIRE

    Lee, Jung Yeop; Janes, Brian K.; Passalacqua, Karla D; Pfleger, Brian F.; Bergman, Nicholas H; Liu, Haichuan; Håkansson, Kristina; Somu, Ravindranadh V.; Aldrich, Courtney C.; Cendrowski, Stephen; Hanna, Philip C.; Sherman, David H.

    2006-01-01

    The asbABCDEF gene cluster from Bacillus anthracis is responsible for biosynthesis of petrobactin, a catecholate siderophore that functions in both iron acquisition and virulence in a murine model of anthrax. We initiated studies to determine the biosynthetic details of petrobactin assembly based on mutational analysis of the asb operon, identification of accumulated intermediates, and addition of exogenous siderophores to asb mutant strains. As a starting point, in-frame deletions of each of...

  16. Purification and characterization of phenoloxidase from brine shrimp Artemia sinica

    Institute of Scientific and Technical Information of China (English)

    Tingjun Fan; Zhao Jing; Xianyuan Fan; Miaomiao Yu; Guojian Jiang

    2011-01-01

    Phenoloxidase from Artemia sinica (AsPO) was purified by Superdex 200 gel-filtration and Q Sepharose fast flow ionexchange chromatography,and its properties were characterized biochemically and enzymatically by using L-dihydroxyphenylalanine (L-DOPA) as the specific substrate.Results showed that AsPO was isolated as a monomeric protein of 125.5 kDa in molecular mass.The optimal pH value and temperature are 7.0 and 50℃,respectively,for its PO activity.The AsPO had an apparent Km value of 4.2 mM on L-DOPA,and 10.9 mM on catechol,respectively.Oxidase inhibitor on PO activity showed that the AsPO was extremely sensitive to ascorbic acid,sodium sulfite,and citric acid; and was very sensitive to cysteine,benzoic acid,and l-phenyl-2-thiourea.Combined with its specific enzyme activity on L-DOPA and catechol,it can be concluded that AsPO is most probably a typical catechol-type O-diphenoloxidase.Its PO activity was also sensitive to metal ions and chelators,and 20 mM DETC-inhibited PO activity was obviously recovered by 15 mM Cu2+,indicating that AsPO is most probably a copper-containing metalloenzyme.All these data about specific substrate,sensitivity to oxidase inhibitor metal ions and chelators indicate that the AsPO has the properties of a catechol-type copper-containing Odiphenoloxidase that functions as a vital humoral factor in host defense via melaninization as in other Crustaceans.

  17. Acetonide Protection of Dopamine for the Synthesis of Highly Pure N-docosahexaenoyldopamine

    OpenAIRE

    Liu, Zhongqiang; Hu, Bi-Huang; Messersmith, Phillip B.

    2010-01-01

    Direct acetonide protection of the catechol of dopamine has proven to be problematic due to formation of Pictet-Spengler isoquinolines. Here we report an efficient method for acetonide protection of dopamine, allowing preparation of a dopamine prodrug without complications from the Pictet-Spengler reaction. Acetonide-protected dopamine was first synthesized by pre-protecting the amino group with phthaloyl followed by refluxing with 2,2-dimethoxypropane in the presence of TsOH. Further work de...

  18. IroN Functions as a Siderophore Receptor and Is a Urovirulence Factor in an Extraintestinal Pathogenic Isolate of Escherichia coli

    OpenAIRE

    Russo, Thomas A.; McFadden, Catherine D.; Carlino-MacDonald, Ulrike B.; Beanan, Janet M.; Barnard, Travis J; Johnson, James R.

    2002-01-01

    IroN was recently identified in the extracellular pathogenic Escherichia coli strain CP9. In this study experimental evidence demonstrating that IroN mediates utilization of the siderophore enterobactin was obtained, thereby establishing IroN as a catecholate siderophore receptor. In a mouse model of ascending urinary tract infection the presence of iroN contributed significantly to CP9's ability to colonize the mouse bladder, kidneys, and urine, evidence that IroN is a urovirulence factor. H...

  19. Poly-N-vinylamid-modifizierte Elektrode als Komponente eines spektroelektrochemischen Sensors für Catecholderivate

    OpenAIRE

    Renner, Karin

    2005-01-01

    A series of poly(N-vinyl amide) copolymers have been synthesised by radical polymerisation from N-vinylpyrrolidone (NVP) and N-vinylphthalimide (NVPH). The suitability of the copolymers for a permselective membrane for a spectroelectrochemical sensor was studied with the goal to detect catechol derivatives. A copolymer with a NVP-NVPH ratio of 3:1 exhibited the required balance of hydrophobic and hydrophilic behaviour. The copolymer was transparent to wavelengths > 300 nm. The copolymer was a...

  20. Chromatographic studies of gamma radiolysis products of phenols in methanolic solution

    International Nuclear Information System (INIS)

    The radiolytic effects on phenolic compounds (catechol, resorcinol, hydroquinone and pyrogallol), under different doses of gamma irradiation, were studied. The results shown that the radiolytic effects are independent of the irradiation doses with almost all compounds formed from the solvent radiolysis. Analysis of the resulting products were carried out by High Performance Liquid Chromatography and Capillary Gas Chromatography. The quantification of these compounds was made by mass spectrometry. (author)

  1. A potential interaction between COMT and MTHFR genetic variants in Han Chinese patients with bipolar II disorder

    OpenAIRE

    Wang, Liang-Jen; Lee, Sheng-Yu; Chen, Shiou-Lan; Chang, Yun-Hsuan; Chen, Po See; Huang, San-Yuan; Tzeng, Nian-Sheng; Chen, Kao Chin; Lee, I Hui; Wang, Tzu-Yun; Yang, Yen Kuang; Lu, Ru-Band

    2015-01-01

    Bipolar II disorder (BP-II), characterized by recurrent dysregulation of mood, is a serious and chronic psychiatric illness. However, BP-II is commonly under-recognized, even in psychiatric settings. Because dopaminergic disturbance is thought to be involved in the development of bipolar disorder (BPD), it seems essential to investigate dopamine-related genes like the catechol-O-methyltransferase (COMT) gene, which are involved in dopamine metabolism, and the methylenetetrahydrofolate reducta...

  2. Polymorphism in COMT is associated with IgG3 subclass level and susceptibility to infection in patients with chronic fatigue syndrome

    OpenAIRE

    Löbel, Madlen; Mooslechner, Agnes Anna; Bauer, Sandra; Günther, Sabrina; Letsch, Anne; Hanitsch, Leif G; Grabowski, Patricia; Meisel, Christian; Volk, Hans-Dieter; Scheibenbogen, Carmen

    2015-01-01

    Background Chronic fatigue syndrome (CFS) is considered as a neuroimmunological disease but the etiology and pathophysiology is poorly understood. Patients suffer from sustained exhaustion, cognitive impairment and an increased sensitivity to pain and sensory stimuli. A subset of patients has frequent respiratory tract infections (RRTI). Dysregulation of the sympathetic nervous system and an association with genetic variations in the catechol-O-methyltransferase (COMT) and glucocorticoid rece...

  3. The Effects of The COMT val108/158met Polymorphism on BOLD Activation During Working Memory, Planning, and Response Inhibition: A Role for The Posterior Cingulate Cortex?

    OpenAIRE

    Stokes, Paul Robert Alexander; Rhodes, Rebecca Anne; Grasby, Paul M.; Mehta, Mitul A

    2010-01-01

    Abstract Catechol-O-methyl transferase (COMT) val108/158met polymorphism impacts upon cortical dopamine levels and may influence functional magnetic resonance (fMRI) measures of task-related neuronal activity. Here, we investigate whether COMT genotype influences cortical activations, particularly prefrontal activations, by interrogating its effect across three tasks that have been associated with the dopaminergic system in a large cohort of healthy volunteers. 58 participants (13 ...

  4. A low COMT activity haplotype is associated with recurrent preeclampsia in a Norwegian population cohort (HUNT2)

    OpenAIRE

    Roten, L.T.; Fenstad, M.H.; Forsmo, S.; Johnson, M P; Moses, E.K.; Austgulen, R; Skorpen, F

    2011-01-01

    The etiology of preeclampsia is complex, with susceptibility being attributable to multiple environmental factors and a large genetic component. Although many candidate genes for preeclampsia have been suggested and studied, the specific causative genes still remain to be identified. Catechol-O-methyltransferase (COMT) is an enzyme involved in catecholamine and estrogen degradation and has recently been ascribed a role in development of preeclampsia. In the present study, we have examined the...

  5. Anhedonia as a Phenotype for the Val158Met COMT Polymorphism in Relatives of Schizophrenia Patients1

    OpenAIRE

    Docherty, Anna R.; Sponheim, Scott R.

    2008-01-01

    The Val158Met polymorphism of the catechol-O-methyltransferase (COMT) gene has been associated with aspects of schizophrenia that are possibly related to the disorder’s pathogenesis. The present study investigated the Val158Met polymorphism in relation to anhedonia—a construct central to negative schizotypy. Anhedonia and other schizotypal characteristics were assessed in relatives of schizophrenia patients, relatives of bipolar patients, and nonpsychiatric controls using the Chapman schizoty...

  6. COMT Val158Met polymorphism, verbalizing of emotion and activation of affective brain systems

    OpenAIRE

    Swart, Marte; Bruggeman, Richard; Laroi, Frank; Alizadeh, Behrooz Z.; Kema, Ido; Kortekaas, Rudie; Wiersma, Durk; Aleman, Andre

    2011-01-01

    Genetic variation in the catechol-O-methyltransferase (COMT) Val158Met polymorphism has been shown to influence performance on cognitive and emotional tasks. Specifically, it has been suggested that the Met allele might be less advantageous than the Val allele with respect to emotional processing. This study addresses the question whether the presence of the Met allele is directly related to both lower emotional verbalizing proficiency and differences in brain activation during emotional proc...

  7. Count on dopamine: influences of COMT polymorphisms on numerical cognition

    OpenAIRE

    AnneliseJúlio-Costa; BárbaraCecíliaMoreira; GabrielleSouzaVianna; GuilhermeWood; Maria RaquelSantosCarvalho

    2013-01-01

    Catechol-O-methyltransferase (COMT) is an enzyme that is particularly important for the metabolism of dopamine. Functional polymorphisms of COMT have been implicated in working memory and numerical cognition. This is an exploratory study that aims at investigating associations between COMT polymorphisms, working memory, and numerical cognition. Elementary school children from 2th to 6th grades were divided into two groups according to their COMT val158met polymorphism [homozygous for valine a...

  8. Lack of association between COMT gene polymorphism and treatment outcome in major depression

    OpenAIRE

    Selek, Salih; Kaya, Mehmet C.; Erdal, Mehmet Emin; Bulut, Mahmut; Ozen, Murat Eren; Yumru, Mehmet; Barlas, Ömer; Kalenderoglu, Aysun; Herken, Hasan

    2011-01-01

    Background & Aim: Abnormal activity of Catechol-O-methyl transferase (COMT), as a major degrading enzyme of catecholaminergic neurotransmitters may be enrolled in the pathogenesis of mood disorders. The aim of this study was to investigate the association between COMT genetic polymorphism and major depression patients. Method: The study included 137 unrelated major depressive disorder (MDD) patients and 153 healthy unrelated controls, all were of Turkish origin. The patients were trea...

  9. No Association Between Functional Polymorphisms in COMT and MTHFR and Schizophrenia Risk in Korean Population

    OpenAIRE

    Kang, Ho Jin; Choe, Byeong Moo; Kim, Seong Hwan; Son, Seung-Rak; Lee, Kyoung-Mu; Kim, Byoung Gwon; Hong, Young-Seoub

    2010-01-01

    OBJECTIVES Common genetic SNPs in two genes, encoding catechol-O-methyltransferase (COMT) and methylenetetrahydrofolate reductase (MTHFR), which are interconnected with COMT gene regulation, have been reported to contribute to schizophrenia risk. In this study, we evaluated the association between functional polymorphisms in COMT and MTHFR and schizophrenia risk with a case-control study in a Korean population. METHODS We performed a case-control study by genotyping analysis using 360 cases a...

  10. Putative cortical dopamine levels affect cortical recruitment during planning ☆

    OpenAIRE

    Fallon, S.J.; Hampshire, A.; Williams-Gray, C.H.; Barker, R A; Owen, A. M.

    2013-01-01

    Planning, the decomposition of an ultimate goal into a number of sub-goals is critically dependent upon fronto-striatal dopamine (DA) levels. Here, we examined the extent to which the val158met polymorphism in the catechol O-methyltransferase (COMT) gene, which is thought to primarily alter cortical DA levels, affects performance and fronto-parietal activity during a planning task (Tower of London). COMT genotype was found to modulate activity in the left superior posterior parietal cortex (S...

  11. Influence of COMT genotype and affective distractors on the processing of self-generated thought

    OpenAIRE

    Kilford, E. J.; Dumontheil, I.; Wood, N. W.; Blakemore, S. J.

    2014-01-01

    The catechol-O-methyltransferase (COMT) enzyme is a major determinant of prefrontal dopamine levels. The Val158Met polymorphism affects COMT enzymatic activity and has been associated with variation in executive function and affective processing. This study investigated the effect of COMT genotype on the flexible modulation of the balance between processing self-generated and processing stimulus-oriented information, in the presence or absence of affective distractors. Analyses included 124 h...

  12. COMT Val158Met Polymorphism, Executive Dysfunction, and Sexual Risk Behavior in the Context of HIV Infection and Methamphetamine Dependence

    OpenAIRE

    Bousman, C. A.; Cherner, M.; Atkinson, J.H.; Heaton, R. K.; GRANT, I.; Everall, I. P.; The HNRC Group

    2010-01-01

    Catechol-O-methyltransferease (COMT) metabolizes prefrontal cortex dopamine (DA), a neurotransmitter involved in executive behavior; the Val158Met genotype has been linked to executive dysfunction, which might increase sexual risk behaviors favoring HIV transmission. Main and interaction effects of COMT genotype and executive functioning on sexual risk behavior were examined. 192 sexually active nonmonogamous men completed a sexual behavior questionnaire, executive functioning tests, and were...

  13. Genetic contributions to age-related decline in executive function: a 10-year longitudinal study of COMT and BDNF polymorphisms

    OpenAIRE

    Erickson, Kirk I.; Suever, Barbara L.; B. Magnus Francis; Kramer, Arthur F.

    2008-01-01

    Genetic variability in the dopaminergic and neurotrophic systems could contribute to age-related impairments in executive control and memory function. In this study we examined whether genetic polymorphisms for catechol-O-methyltransferase (COMT) and brain-derived neurotrophic factor (BDNF) were related to the trajectory of cognitive decline occurring over a 10-year period in older adults. A single-nucleotide polymorphism (SNP) in the COMT (Val158/108Met) gene affects the concentration of d...

  14. COMT val158met Genotype Affects Recruitment of Neural Mechanisms Supporting Fluid Intelligence

    OpenAIRE

    Bishop, Sonia J.; Fossella, John; Croucher, Camilla J.; Duncan, John

    2008-01-01

    Fluid intelligence (g f) influences performance across many cognitive domains. It is affected by both genetic and environmental factors. Tasks tapping g f activate a network of brain regions including the lateral prefrontal cortex (LPFC), the presupplementary motor area/anterior cingulate cortex (pre-SMA/ACC), and the intraparietal sulcus (IPS). In line with the “intermediate phenotype” approach, we assessed effects of a polymorphism (val158met) in the catechol-O-methyltransferase (COMT) gene...

  15. Association between the COMT Val158Met polymorphism and risk of cancer: evidence from 99 case–control studies

    OpenAIRE

    Zhou, Quan; Wang, Yan; Chen, Aihua; Tao, Yaling; Song, Huamei; Li, Wei; Tao, Jing; Zuo, Manzhen

    2015-01-01

    Catechol-O-methyltransferase (COMT) plays a central role in DNA repair and estrogen-induced carcinogenesis. Many recent epidemiologic studies have investigated the association between the COMT Val158Met polymorphism and cancer risk, but the results are inconclusive. In this study, we performed a meta-analysis to investigate the association between cancer susceptibility and COMT Val158Met in different genetic models. Overall, no significant associations were found between COMT Val158Met polymo...

  16. Association between the COMT Val158Met polymorphism and risk of cancer: evidence from 99 case–control studies

    OpenAIRE

    Zhou Q; Wang Y; Chen AH; Tao YL; Song HM; Li W.; Tao J.; Zuo MZ

    2015-01-01

    Quan Zhou, Yan Wang, Aihua Chen, Yaling Tao, Huamei Song, Wei Li, Jing Tao, Manzhen ZuoDepartment of Gynecology and Obstetrics, The People’s Hospital of Three Gorges University, The First People’s Hospital of Yichang, Yichang, People’s Republic of ChinaAbstract: Catechol-O-methyltransferase (COMT) plays a central role in DNA repair and estrogen-induced carcinogenesis. Many recent epidemiologic studies have investigated the association between the COMT Val158Met polymorphism ...

  17. A Haplotype Implicated in Schizophrenia Susceptibility Is Associated with Reduced COMT Expression in Human Brain

    OpenAIRE

    Bray, Nicholas J.; Buckland, Paul R.; Williams, Nigel M.; Williams, Hywel J.; Norton, Nadine; Owen, Michael J; O’Donovan, Michael C

    2003-01-01

    The gene encoding catechol-O-methyltransferase (COMT) is a strong candidate for schizophrenia susceptibility, owing to the role of COMT in dopamine metabolism, and the location of the gene within the deleted region in velocardiofacial syndrome, a disorder associated with high rates of schizophrenia. Recently, a highly significant association was reported between schizophrenia and a COMT haplotype in a large case-control sample (Shifman et al. 2002). In addition to a functional valine→methioni...

  18. Association of COMT genotypes with S-COMT promoter methylation in growth-discordant monozygotic twins and healthy adults

    OpenAIRE

    Schreiner Felix; El-Maarri Osman; Gohlke Bettina; Stutte Sonja; Nuesgen Nicole; Mattheisen Manuel; Fimmers Rolf; Bartmann Peter; Oldenburg Johannes; Woelfle Joachim

    2011-01-01

    Abstract Background Catechol-O-Methyltransferase (COMT) plays a key role in dopamine and estrogen metabolism. Recently, COMT haplotypes rather than the single polymorphism Val158Met have been reported to underlie differences in protein expression by modulating mRNA secondary structure. So far, studies investigating the epigenetic variability of the S-COMT (soluble COMT) promoter region mainly focused on phenotypical aspects, and results have been controversial. Methods We assessed S-COMT prom...

  19. COMT Val158Met polymorphism, cognitive stability and cognitive flexibility: an experimental examination

    OpenAIRE

    Rosa Elise C; Dickinson Dwight; Apud José; Weinberger Daniel R; Elvevåg Brita

    2010-01-01

    Abstract Background Dopamine in prefrontal cortex (PFC) modulates core cognitive processes, notably working memory and executive control. Dopamine regulating genes and polymorphisms affecting PFC - including Catechol-O-Methyltransferase (COMT) Val158Met - are crucial to understanding the molecular genetics of cognitive function and dysfunction. A mechanistic account of the COMT Val158Met effect associates the Met allele with increased tonic dopamine transmission underlying maintenance of rele...

  20. Lack of Association Between COMT and Working Memory in a Population-Based Cohort of Healthy Young Adults

    OpenAIRE

    Wardle, Margaret C; de Wit, Harriet; Penton-Voak, Ian; Lewis, Glyn; Munafò, Marcus R.

    2013-01-01

    The Val158Met polymorphism of the catechol-O-methyltransferase (COMT) gene is an important regulator of dopamine in the prefrontal cortex, an area critical to working memory. Working memory deficits are present in several psychiatric disorders, and there is wide variation in working memory capacity in the normal population. Association studies of COMT and working memory in healthy volunteers have yielded inconsistent results, possibly because of small sample sizes. Here we examine COMT in rel...