Sample records for oryzae catechol oxidase

  1. An association study of catechol- O-methyltransferase and monoamine oxidase A polymorphisms and personality traits in Koreans

    Microsoft Academic Search

    Se Joo Kim; Young Shin Kim; Shin Young Kim; Hong Shick Lee; Chan-Hyung Kim

    2006-01-01

    Catechol-O-methyltransferase (COMT) and monoamine oxidase A (MAOA) are both involved in the degradation of various biogenic amines which have been hypothesized to have a relationship with personality traits. The present study investigated the possible relationships between the genotypes of COMT Val158Met and MAOA-uVNTR polymorphisms and personality traits measured by the Temperament and Character Inventory (TCI). We recruited 286 normal, unrelated

  2. Multipart copolyelectrolyte adhesive of the sandcastle worm, Phragmatopoma californica (Fewkes): catechol oxidase catalyzed curing through peptidyl-DOPA.

    PubMed

    Wang, Ching Shuen; Stewart, Russell J

    2013-05-13

    Tube-building sabellariid polychaetes have major impacts on the geology and ecology of shorelines worldwide. Sandcastle worms, Phragmatopoma californica (Fewkes), live along the western coast of North America. Individual sabellariid worms build tubular shells by gluing together mineral particles with a multipart polyelectrolytic adhesive. Distinct sets of oppositely charged components are packaged and stored in concentrated granules in separate cell types. Homogeneous granules contain sulfated macromolecules as counter-polyanion to polycationic Pc2 and Pc5 proteins, which become major components of the fully cured glue. Heterogeneous granules contain polyphosphoproteins, Pc3A/B, paired with divalent cations and polycationic Pc1 and Pc4 proteins. Both types of granules contain catechol oxidase that catalyzes oxidative cross-linking of L-DOPA. Co-secretion of catechol oxidase guarantees rapid and spatially homogeneous curing with limited mixing of the preassembled adhesive packets. Catechol oxidase remains active long after the glue is fully cured, perhaps providing an active cue for conspecific larval settlement. PMID:23530959

  3. Monoamine oxidase a and catechol-o-methyltransferase functional polymorphisms and the placebo response in major depressive disorder.

    PubMed

    Leuchter, Andrew F; McCracken, James T; Hunter, Aimee M; Cook, Ian A; Alpert, Jonathan E

    2009-08-01

    The placebo response shows pronounced interindividual variability. Placebos are postulated to act through central reward pathways that are modulated by monoamines. Because monoaminergic signaling is under strong genetic control, we hypothesized that common functional polymorphisms modulating monoaminergic tone would be related to degree of improvement during placebo treatment of subjects with major depressive disorder. We examined polymorphisms in genes encoding the catabolic enzymes catechol-O-methyltransferase and monoamine oxidase A. Subjects with monoamine oxidase A G/T polymorphisms (rs6323) coding for the highest activity form of the enzyme (G or G/G) had a significantly lower magnitude of placebo response than those with other genotypes. Subjects with ValMet catechol-O-methyltransferase polymorphisms coding for a lower-activity form of the enzyme (2 Met alleles) showed a statistical trend toward a lower magnitude of placebo response. These findings support the hypothesis that genetic polymorphisms modulating monoaminergic tone are related to degree of placebo responsiveness in major depressive disorder. PMID:19593178

  4. Secreted fungal sulfhydryl oxidases: sequence analysis and characterisation of a representative flavin-dependent enzyme from Aspergillus oryzae

    PubMed Central

    2010-01-01

    Background Sulfhydryl oxidases are flavin-dependent enzymes that catalyse the formation of de novo disulfide bonds from free thiol groups, with the reduction of molecular oxygen to hydrogen peroxide. Sulfhydryl oxidases have been investigated in the food industry to remove the burnt flavour of ultraheat-treated milk and are currently studied as potential crosslinking enzymes, aiming at strengthening wheat dough and improving the overall bread quality. Results In the present study, potential sulfhydryl oxidases were identified in the publicly available fungal genome sequences and their sequence characteristics were studied. A representative sulfhydryl oxidase from Aspergillus oryzae, AoSOX1, was expressed in the fungus Trichoderma reesei. AoSOX1 was produced in relatively good yields and was purified and biochemically characterised. The enzyme catalysed the oxidation of thiol-containing compounds like glutathione, D/L-cysteine, beta-mercaptoethanol and DTT. The enzyme had a melting temperature of 57°C, a pH optimum of 7.5 and its enzymatic activity was completely inhibited in the presence of 1 mM ZnSO4. Conclusions Eighteen potentially secreted sulfhydryl oxidases were detected in the publicly available fungal genomes analysed and a novel proline-tryptophan dipeptide in the characteristic motif CXXC, where X is any amino acid, was found. A representative protein, AoSOX1 from A. oryzae, was produced in T. reesei in an active form and had the characteristics of sulfhydryl oxidases. Further testing of the activity on thiol groups within larger peptides and on protein level will be needed to assess the application potential of this enzyme. PMID:20727152

  5. Functional Analysis of Fructosyl-Amino Acid Oxidases of Aspergillus oryzae

    PubMed Central

    Akazawa, Shin-ichi; Karino, Tetsuya; Yoshida, Nobuyuki; Katsuragi, Tohoru; Tani, Yoshiki

    2004-01-01

    Three active fractions of fructosyl-amino acid oxidase (FAOD-Ao1, -Ao2a, and -Ao2b) were isolated from Aspergillus oryzae strain RIB40. N-terminal and internal amino acid sequences of FAOD-Ao2a corresponded to those of FAOD-Ao2b, suggesting that these two isozymes were derived from the same protein. FAOD-Ao1 and -Ao2 were different in substrate specificity and subunit assembly; FAOD-Ao2 was active toward N?-fructosyl N?-Z-lysine and fructosyl valine (Fru-Val), whereas FAOD-Ao1 was not active toward Fru-Val. The genes encoding the FAOD isozymes (i.e., FAOAo1 and FAOAo2) were cloned by PCR with an FAOD-specific primer set. The deduced amino acid sequences revealed that FAOD-Ao1 was 50% identical to FAOD-Ao2, and each isozyme had a peroxisome-targeting signal-1, indicating their localization in peroxisomes. The genes was expressed in Escherichia coli and rFaoAo2 showed the same characteristics as FAOD-Ao2, whereas rFaoAo1 was not active. FAOAo2 disruptant was obtained by using ptrA as a selective marker. Wild-type strain grew on the medium containing Fru-Val as the sole carbon and nitrogen sources, but strain ?faoAo2 did not grow. Addition of glucose or (NH4)2SO4 to the Fru-Val medium did not affect the assimilation of Fru-Val by wild-type, indicating glucose and ammonium repressions did not occur in the expression of the FAOAo2 gene. Furthermore, conidia of the wild-type strain did not germinate on the medium containing Fru-Val and NaNO2 as the sole carbon and nitrogen sources, respectively, suggesting that Fru-Val may also repress gene expression of nitrite reductase. These results indicated that FAOD is needed for utilization of fructosyl-amino acids as nitrogen sources in A. oryzae. PMID:15466528

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

    NASA Astrophysics Data System (ADS)

    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.

  7. Anion coordination selective [Mn3] and [Mn4] assemblies: synthesis, structural diversity, magnetic properties and catechol oxidase activity.

    PubMed

    Pait, Moumita; Shatruk, Michael; Ray, Debashis

    2015-07-14

    Syntheses, crystal structures, magnetic properties and catechol oxidation behavior are presented for [Mn3] and [Mn4] aggregates, [MnMn(II)(O2CMe)4(dmp)2(H2O)2]·2H2O (1·2H2O), [MnMn(II)(O2CCH2Cl)4(dmp)2(H2O)2]·H2O·MeOH (2·H2O·MeOH), [Mn(?3-O)(dmp)4(?-DMSO)(N3)(DMSO)(H2O)]ClO4·DMSO (3·ClO4·DMSO), and [Mn(?3-O)(dmp)4(?-DMSO)(ClO4)(DMSO)(H2O)]ClO4·DMSO (4·ClO4·DMSO), developed with single type ligand H2dmp, 2-[(2-hydroxy-1,1-dimethyl-ethylimino)-methyl]-phenol. The successful isolation of 1-4 resulted from a systematic exploration of the effect of Mn(II) salts, added carboxylates, Mn/H2dmp ratio, presence of azide, and other reaction conditions. The cores of 1 and 2 are similar and consist of a linear Mn(III)Mn(II)Mn(III) unit in a carboxylate and H2dmp environment, revealing a central Mn(II) ion in a different environment and terminal Mn(III) ions available for the introduction of structural and magnetic anisotropy to the system. The cores of 3 and 4 are also similar and consist of a distorted incomplete-adamantane type Mn4 coordination assembly in a carboxylate-free environment built on a triangular [Mn(?3-O)] unit. The magnetic behavior of complexes 1-3 is dominated by antiferromagnetic exchange coupling that results in ground state spin values of S = 3/2 for 1 and 2 and S = 0 for 3. In solution, all four complexes 1-4 show catechol oxidation activity towards 3,5-DTBC. The catalytic activity for the oxidation of 3,5-DTBC in air followed the order 4 < 3 < 1 < 2. PMID:26050820

  8. Gonadectomy and Hormone Replacement Exert Region- and Enzyme Isoform-Specific Effects on Monoamine Oxidase and Catechol-O-Methyltransferase Activity in Prefrontal Cortex and Neostriatum of Adult Male Rats

    PubMed Central

    Meyers, B.; D'Agostino, A.; Walker, J.; Kritzer, M. F.

    2010-01-01

    Sex differences and gonadal hormone influences are well known for diverse aspects of forebrain amine and indolamine neurotransmitter systems, the cognitive and affective functions they govern and their malfunction in mental illness. This study explored whether hormone regulation/dysregulation of these systems could be related to gonadal steroid effects on catechol-O-methyltransferase and monoamine oxidase which are principal enzymatic controllers of forebrain dopamine, serotonin and norepinephrine levels. Driven by male over female differences in cortical enzyme activities, by male-specific associations between monoamine oxidase and catechol-O-methyltransferase gene polymorphisms and cognitive and dysfunction in disease and by male-specific consequences of gene knockouts in mice, the question of hormone sensitivity was addressed here using a male rat model where prefrontal dopamine levels and related behaviors are also known to be affected. Specifically, quantitative O-methylation and oxidative deamination assays were used to compare the activities of catechol-O-methyltransferase's soluble and membrane-bound isoforms and of monoamine oxidase's A and B isoforms in the pregenual medial prefrontal cortex and dorsal striatum of male rats that were sham operated, gonadectomized or gonadectomized and supplemented with testosterone propionate or with estradiol for 28 days. These studies revealed significant effects of hormone replacement but not gonadectomy on the soluble but not the membrane-bound isorfom of catechol-O-methyltransferase in both striatum and cortex. A significant, cortex-specific testosterone—but not estradiol—attenuated effect (increase) of gonadectomy on monoamine oxidase's A but not B isoform was also observed. Although none of these actions suggest potential roles in the reguation/dysregulation of prefrontal dopamine, the suppressive effects of testosterone on cortical monoamine oxidase-A that were observed could have bearing on the increased incidence of cognitive deficits and symptoms of depression and anxiety that are repeatedly observed in males in conditions of hypogonadalism related to aging, other biological factors or in prostate cancer where androgen deprivation is used as a neoadjuvant treatment. PMID:19909795

  9. Relation between the catalytic efficiency of the synthetic analogues of catechol oxidase with their electrochemical property in the free state and substrate-bound state.

    PubMed

    Chakraborty, Prateeti; Adhikary, Jaydeep; Ghosh, Bipinbihari; Sanyal, Ria; Chattopadhyay, Shyamal Kumar; Bauzá, Antonio; Frontera, Antonio; Zangrando, Ennio; Das, Debasis

    2014-08-18

    A library of 15 dicopper complexes as synthetic analogues of catechol oxidase has been synthesized with the aim to determine the relationship between the electrochemical behavior of the dicopper(II) species in the absence as well as in the presence of 3,5-di-tert-butylcatechol (3,5-DTBC) as model substrate and the catalytic activity, kcat, in DMSO medium. The complexes have been characterized by routine physicochemical techniques as well as by X-ray single-crystal structure analysis in some cases. Fifteen "end-off" compartmental ligands have been designed as 1 + 2 Schiff-base condensation product of 2,6-diformyl-4-R-phenol (R = Me, (t)Bu, and Cl) and five different amines, N-(2-aminoethyl)piperazine, N-(2-aminoethyl)pyrrolidine, N-(2-aminoethyl)morpholine, N-(3-aminopropyl)morpholine, and N-(2-aminoethyl)piperidine. Interestingly, in case of the combination of 2,6-diformyl-4-methylphenol and N-(2-aminoethyl)morpholine/N-(3-aminopropyl)morpholine/N-(2-aminoethyl)piperidine 1 + 1 condensation becomes the reality and the ligands are denoted as L2(1-3). On reaction of copper(II) nitrate with L2(1-3) in situ complexes 3, 12, and 13 are formed having general formula Cu2(L2(1-3))2(NO3)2. The remaining 12 ligands obtained as 1 + 2 condensation products are denoted as L1(1-12), which produce complexes having general formula Cu2(L1(1-12))(NO3)2. Catecholase activity of all 15 complexes has been investigated in DMSO medium using 3,5-DTBC as model substrate. Treatment on the basis of Michaelis-Menten model has been applied for kinetic study, and thereby turnover number, kcat, values have been evaluated. Cyclic voltametric (CV) and differential pulse voltametric (DPV) studies of the complexes in the presence as well as in the absence of 3,5-DTBC have been thoroughly investigated in DMSO medium. From those studies it is evident that oxidation of 3,5-DTBC catalyzed by dicopper(II) complexes proceed via two steps: first, semibenzoquinone followed by benzoquinone with concomitant reduction of Cu(II) to Cu(I). Our study reveals that apparently there is nearly no linear relationship between kcat and E° values of the complexes. However, a detailed density functional theory (DFT) calculation sheds light on this subject. A very good correlation prevails in terms of the energetics associated with the Cu(II) to Cu(I) reduction process and kcat values, as revealed from the combined theoretical and experimental approach. PMID:25072328

  10. Secreted fungal sulfhydryl oxidases: sequence analysis and characterisation of a representative flavin-dependent enzyme from Aspergillus oryzae

    Microsoft Academic Search

    Greta Faccio; Kristiina Kruus; Johanna Buchert; Markku Saloheimo

    2010-01-01

    BACKGROUND: Sulfhydryl oxidases are flavin-dependent enzymes that catalyse the formation of de novo disulfide bonds from free thiol groups, with the reduction of molecular oxygen to hydrogen peroxide. Sulfhydryl oxidases have been investigated in the food industry to remove the burnt flavour of ultraheat-treated milk and are currently studied as potential crosslinking enzymes, aiming at strengthening wheat dough and improving

  11. Identification of catechol as a new marker for detecting propolis adulteration.

    PubMed

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

    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 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. PMID:25025150

  12. Spectroscopic Studies of the Catechol Dioxygenases.

    ERIC Educational Resources Information Center

    Que, Lawrence Jr.

    1985-01-01

    The catechol dioxygenases are bacterial iron-containing enzymes that catalyze the oxidative cleavage of catechols. These enzymes serve as a component of nature's mechanisms for degrading aromatic compounds in the environment. The structure and mechanistic aspects of these enzymes are described. (JN)

  13. Photocatalytic destruction of catechol on illuminated titania

    Microsoft Academic Search

    Andrzej Sobczy?ski; ?ukasz Duczmal

    2004-01-01

    First-order kinetics was found for the photocatalytic oxidation of catechol on TiO2. Kinetic constants calculated from the Langmuir-Hinshelwood equation are: k=2.03x10-8 mol dm-3 s-1; Kads=1.63x104 dm3 mol-1. Full catechol mineralization is a multistep reaction, 1,2,4-benzenetriol and glycol are the main intermediates.

  14. Oxidase Test Protocol

    NSDL National Science Digital Library

    American Society For Microbiology

    2010-11-11

    The oxidase test is used to detect the presence of the enzyme cytochrome oxidase in microorganisms.  While used as a taxonomic tool for many microorganisms, the test was established initially to differentiate Neisseria spp. (oxidase positive) from Acinetobacter (oxidase negative) and Pseudomonas spp. (oxidase positive) from the Enterobacteriaceae (oxidase negative).

  15. Laccases and other polyphenol oxidases in ecto- and ericoid mycorrhizal fungi

    Microsoft Academic Search

    R. M. Burke; J. W. G. Cairney

    2002-01-01

    Polyphenol oxidases are known to be produced by a range of ectomycorrhizal (ECM) and ericoid mycorrhizal fungi. These enzymes include laccase (EC 1.10.3.2), catechol oxidase (EC 1.10.3.1) and tyrosinase (EC 1.14.18.1), between which there exists considerable overlap in substrate affinities. In this review we consider the nature and function of these enzymes, along with the difficulties associated with assigning precise

  16. Catecholate Siderophores Protect Bacteria from Pyochelin Toxicity

    PubMed Central

    Adler, Conrado; Corbalán, Natalia S.; Seyedsayamdost, Mohammad R.; Pomares, María Fernanda; de Cristóbal, Ricardo E.; Clardy, Jon; Kolter, Roberto; Vincent, Paula A.

    2012-01-01

    Background Bacteria produce small molecule iron chelators, known as siderophores, to facilitate the acquisition of iron from the environment. The synthesis of more than one siderophore and the production of multiple siderophore uptake systems by a single bacterial species are common place. The selective advantages conferred by the multiplicity of siderophore synthesis remains poorly understood. However, there is growing evidence suggesting that siderophores may have other physiological roles besides their involvement in iron acquisition. Methods and Principal Findings Here we provide the first report that pyochelin displays antibiotic activity against some bacterial strains. Observation of differential sensitivity to pyochelin against a panel of bacteria provided the first indications that catecholate siderophores, produced by some bacteria, may have roles other than iron acquisition. A pattern emerged where only those strains able to make catecholate-type siderophores were resistant to pyochelin. We were able to associate pyochelin resistance to catecholate production by showing that pyochelin-resistant Escherichia coli became sensitive when biosynthesis of its catecholate siderophore enterobactin was impaired. As expected, supplementation with enterobactin conferred pyochelin resistance to the entE mutant. We observed that pyochelin-induced growth inhibition was independent of iron availability and was prevented by addition of the reducing agent ascorbic acid or by anaerobic incubation. Addition of pyochelin to E. coli increased the levels of reactive oxygen species (ROS) while addition of ascorbic acid or enterobactin reduced them. In contrast, addition of the carboxylate-type siderophore, citrate, did not prevent pyochelin-induced ROS increases and their associated toxicity. Conclusions We have shown that the catecholate siderophore enterobactin protects E. coli against the toxic effects of pyochelin by reducing ROS. Thus, it appears that catecholate siderophores can behave as protectors of oxidative stress. These results support the idea that siderophores can have physiological roles aside from those in iron acquisition. PMID:23071628

  17. Identification of the active-site peptide of 2,3-dihydroxybenzoic acid decarboxylase from Aspergillus oryzae

    Microsoft Academic Search

    R. Santha; N. Appaji Rao; C. S. Vaidyanathan

    1996-01-01

    The non-oxidative decarboxylation of aromatic acids is a poorly understood reaction. The transformation of 2,3-dihydroxybenzoic acid to catechol in the fungal metabolism of indole is a prototype of such a reaction. 2,3-Dihydroxybenzoic acid decarboxylase (EC 4.1.1.46) which catalyzes this reaction was purified to homogeneity from anthranilate induced cultures of Aspergillus oryzae using affinity chromatography. The enzyme did not require cofactors

  18. Nitroderivatives of catechol: from synthesis to application.

    PubMed

    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

  19. Catechol metabolites of the mycotoxin zearalenone are poor substrates but potent inhibitors of catechol-O-methyltransferase.

    PubMed

    Pfeiffer, Erika; Wefers, Daniel; Hildebrand, Andreas A; Fleck, Stefanie C; Metzler, Manfred

    2013-08-01

    The mycotoxin zearalenone (ZEN) elicits estrogenic effects and is biotransformed to two catechol metabolites, in analogy to the endogenous steroidal estrogen 17ß-estradiol (E2). Previous studies have shown that the catechol metabolites of ZEN have about the same potency to induce oxidative DNA damage as the catechol metabolites of E2, but are less efficiently converted to their methyl ethers by human hepatic catechol-O-methyltransferase (COMT). Here, we report that the two catechol metabolites of ZEN, i.e. 13-hydroxy-ZEN and 15-hydroxy-ZEN, are not only poor substrates of human COMT but are also able to strongly inhibit the O-methylation of 2-hydroxy-E2, the major catechol metabolite of E2. 15-Hydroxy-ZEN acts as a non-competitive inhibitor and is about ten times more potent than 13-hydroxy-ZEN, which is an uncompetitive inhibitor of COMT. The catechol metabolites of ZEN were also shown to inhibit the O-methylation of 2-hydroxy-E2 by hepatic COMT from mouse, rat, steer and piglet, although to a lesser extent than observed with human COMT. The powerful inhibitory effect of catechol metabolites of ZEN on COMT may have implications for the tumorigenic activity of E2, because catechol metabolites of E2 elicit genotoxic effects, and their impaired O-methylation may increase the tumorigenicity of steroidal estrogens. PMID:23558779

  20. Amine Oxidases of Microorganisms

    Microsoft Academic Search

    O. V. Yagodina; E. B. Nikol'skaya; A. E. Khovanskikh; B. N. Kormilitsyn

    2002-01-01

    The review of works on amine oxidases of microorganisms is presented. Preparation, physical-chemical and kinetic properties of amine oxidases from archaebacteria Methanosarcina barkery, group of methane-producing archaebacteria, eubacteria, Sarcina lutea, Micrococcus rubens, M. lutea, representatives of Enterobacteriaceae family, such as Klebsiella and Escherichia, are considered. Besides, the amine oxidases obtained from mycelium of fungus Aspergillus niger are described. The works

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

    PubMed Central

    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

  2. Decolorization of the Textile Dyes Using Purified Banana Pulp Polyphenol Oxidase

    Microsoft Academic Search

    Umesh U. Jadhav; Vishal V. Dawkar; Mital U. Jadhav; Sanjay P. Govindwar

    2011-01-01

    Polyphenol oxidase (PPO) purified using DEAE-cellulose and Biogel P-100 column chromatography from banana pulp showed 12.72-fold activity and 2.49% yield. The optimum temperature and pH were found to be 30°C and 7.0, respectively for its activity. Catechol was found to be a suitable substrate for banana pulp PPO that showed Vmax, 0.041 mM min and Km, 1.6 mM. The enzyme

  3. Purification and Biochemical Characterization of Polyphenol Oxidases from Embryogenic and Nonembryogenic Cotton ( Gossypium hirsutum L.) Cells

    Microsoft Academic Search

    Tanoh Hilaire Kouakou; Yatty Justin Kouadio; Patrice Kouamé; Pierre Waffo-Téguo; Alain Décendit; Jean-Michel Mérillon

    2009-01-01

    Polyphenol oxidases (PPOs) were isolated from cell suspensions of two cultivars of cotton (Gossypium hirsutum L.), and their biochemical characteristics were studied. PPO from Coker 312, an embryogenic cultivar, showed a highest affinity\\u000a to catechol 20 mM, and PPO from R405-2000, a nonembryogenic cultivar, showed a highest affinity to 4-methylcatechol 20 mM.\\u000a The optimal pH for PPO activity was 7.0 and 6.0

  4. Peroxynitrite oxidises catechols to o-quinones.

    PubMed

    Kerry, N; Rice-Evans, C

    1998-10-23

    Nitration of phenolic compounds is a well-established mechanism on interaction with peroxynitrite. However, while nitration is the predominant reaction for monophenolic hydroxycinnamates, this does not take place with the catechol-containing hydroxycinnamate, caffeic acid. The aim of the present study was to investigate the mechanism of the chemical interaction of caffeic acid with peroxynitrite and to characterise the products formed. A novel compound was detected and characterised as the o-quinone of caffeic acid based on its reaction with nucleophilic thiol compounds, glutathione and L-cysteine. The same novel product was identified following the oxidation of caffeic acid in alkaline solutions confirming the identity of this species as a caffeic acid oxidation product. PMID:9824283

  5. Bioinspired catecholic copolymers for antifouling surface coatings.

    PubMed

    Cho, Joon Hee; Shanmuganathan, Kadhiravan; Ellison, Christopher J

    2013-05-01

    We report here a synthetic approach to prepare poly(methyl methacrylate)-polydopamine diblock (PMMA-PDA) and triblock (PDA-PMMA-PDA) copolymers combining mussel-inspired catecholic oxidative chemistry and atom transfer radical polymerization (ATRP). These copolymers display very good solubility in a range of organic solvents and also a broad band photo absorbance that increases with increasing PDA content in the copolymer. Spin-cast thin films of the copolymer were stable in water and showed a sharp reduction (by up to 50%) in protein adsorption compared to those of neat PMMA. Also the peak decomposition temperature of the copolymers was up to 43°C higher than neat PMMA. The enhanced solvent processability, thermal stability and low protein adsorption characteristics of this copolymer makes it attractive for variety of applications including antifouling coatings on large surfaces such as ship hulls, buoys, and wave energy converters. PMID:23544666

  6. Dietary Catechols and their Relationship to Microbial Endocrinology

    Microsoft Academic Search

    Neil Shearer; Nicholas J. Walton

    \\u000a This chapter examines the evidence that the ability of neuroendocrine hormones, notably norepinephrine and epinephrine, to\\u000a stimulate bacterial growth in iron-restricted media is not limited to molecules with a catecholamine structure but is also\\u000a possessed by a variety of other catechols, many of which are of plant origin and are common in the diet. Catechols derived\\u000a from the diet, such

  7. Molecular detection of Xanthomonas oryzae pv. oryzae, Xanthomonas oryzae pv. oryzicola, and Burkholderia glumae in infected rice seeds and leaves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Polymerase chain reaction (PCR) is particularly useful for plant pathogen detection. In the present study, multiplex PCR and SYBR green real-time PCR were developed to facilitate simultaneous detection of three important rice pathogens, Xanthomonas oryzae pv. oryzae, X. oryzae pv. oryzicola, and Bur...

  8. L Amino acid oxidase from filamentous fungi: screening and optimization

    Microsoft Academic Search

    Ashraf S. El-Sayed; Ahmed A. Shindia; Yomna Zaher

    Twenty-seven fungal isolates recovered on medium containing L-lysine were found to have the potentiality for producing extracellular L-amino acid oxidase (L-AAO). Aspergillus oryzae displayed the highest yield of enzyme (2.6 U\\/mg protein) and antioxidants (2.3 mg\\/ml) followed by Aspergillus flavipes and Trichoderma viride. Upon optimization of the fermentation medium, the maximum enzyme yield (4.6 U\\/mg protein) was obtained on a medium containing\\u000a L-lysine

  9. Catechol conjugates are in vivo metabolites of Salicis cortex.

    PubMed

    Knuth, Susanne; Abdelsalam, Rania M; Khayyal, Mohamed T; Schweda, Frank; Heilmann, Jörg; Kees, Martin Georg; Mair, Georg; Kees, Frieder; Jürgenliemk, Guido

    2013-11-01

    After oral administration of 100?mg/kg b.?w. (235.8?µmol/kg) salicortin to Wistar rats, peak serum concentrations of 1.43?mg/L (13.0?µM) catechol were detected after 0.5?h in addition to salicylic acid by HPLC-DAD after serum processing with ?-glucuronidase and sulphatase. Both metabolites could also be detected in the serum of healthy volunteers following oral administration of a willow bark extract (Salicis cortex, Salix spec., Salicaceae) corresponding to 240?mg of salicin after processing with both enzymes. In humans, the cmax (1.46?mg/L, 13.3?µM) of catechol was reached after 1.2?h. The predominant phase-II metabolite in humans and rats was catechol sulphate, determined by HPLC analysis of serum samples processed with only one kind of enzyme. Without serum processing with glucuronidase and sulphatase, no unconjugated catechol could be detected in human and animal serum samples. As catechol is described as an anti-inflammatory compound, these results may contribute to the elucidation of the mechanism of the action of willow bark extract. PMID:24146062

  10. Control of catechol meta-cleavage pathway in Alcaligenes eutrophus.

    PubMed Central

    Hughes, E J; Bayly, R C

    1983-01-01

    Alcaligenes eutrophus 335 (ATCC 17697) metabolizes phenol and p-cresol via a catechol meta-cleavage pathway. Studies with mutant strains, each defective in an enzyme of the pathway, showed that the six enzymes assayed are induced by the primary substrate. Studies with a putative polarity mutant defective in the expression of aldehyde dehydrogenase suggested that the structural genes encoding this and subsequent enzymes of the pathway exist in the same operon. From studies with mutant strains that constitutively synthesize catechol 2,3-oxygenase and subsequent enzymes and from the coordination of repression of these enzymes by p-toluate, benzoate, and acetate, it is proposed the catechol 2,3-oxygenase structural gene is situated in this operon (2,3-oxygenase operon). Studies with regulatory mutant strains suggest that the 2,3-oxygenase operon is under negative control. PMID:6853447

  11. Genome sequence and rapid evolution of the rice pathogen Xanthomonas oryzae pv. oryzae PXO99A

    Microsoft Academic Search

    Steven L Salzberg; Daniel D Sommer; Michael C Schatz; Adam M Phillippy; Pablo D Rabinowicz; Seiji Tsuge; Ayako Furutani; Hirokazu Ochiai; Arthur L Delcher; David Kelley; Ramana Madupu; Daniela Puiu; Diana Radune; Martin Shumway; Cole Trapnell; Gudlur Aparna; Gopaljee Jha; Alok Pandey; Prabhu B Patil; Hiromichi Ishihara; Damien F Meyer; Boris Szurek; Valerie Verdier; Ralf Koebnik; J Maxwell Dow; Robert P Ryan; Hisae Hirata; Shinji Tsuyumu; Sang Won Lee; Pamela C Ronald; Ramesh V Sonti; Marie-Anne Van Sluys; Jan E Leach; Frank F White; Adam J Bogdanove

    2008-01-01

    BACKGROUND: Xanthomonas oryzae pv. oryzae causes bacterial blight of rice (Oryza sativa L.), a major disease that constrains production of this staple crop in many parts of the world. We report here on the complete genome sequence of strain PXO99A and its comparison to two previously sequenced strains, KACC10331 and MAFF311018, which are highly similar to one another. RESULTS: The

  12. Characterization of catechol catabolic genes from Rhodococcus erythropolis 1CP.

    PubMed Central

    Eulberg, D; Golovleva, L A; Schlömann, M

    1997-01-01

    The biochemical characterization of the muconate and the chloromuconate cycloisomerases of the chlorophenol-utilizing Rhodococcus erythropolis strain 1CP previously indicated that efficient chloromuconate conversion among the gram-positive bacteria might have evolved independently of that among gram-negative bacteria. Based on sequences of the N terminus and of tryptic peptides of the muconate cycloisomerase, a fragment of the corresponding gene has now been amplified and used as a probe for the cloning of catechol catabolic genes from R. erythropolis. The clone thus obtained expressed catechol 1,2-dioxygenase, muconate cycloisomerase, and muconolactone isomerase activities. Sequencing of the insert on the recombinant plasmid pRER1 revealed that the genes are transcribed in the order catA catB catC. Open reading frames downstream of catC may have a function in carbohydrate metabolism. The predicted protein sequence of the catechol 1,2-dioxygenase was identical to the one from Arthrobacter sp. strain mA3 in 59% of the positions. The chlorocatechol 1,2-dioxygenases and the chloromuconate cycloisomerases of gram-negative bacteria appear to be more closely related to the catechol 1,2-dioxygenases and muconate cycloisomerases of the gram-positive strains than to the corresponding enzymes of gram-negative bacteria. PMID:8990288

  13. Iron-Binding Catechols and Virulence in Escherichia coli

    PubMed Central

    Rogers, Henry J.

    1973-01-01

    Previous work suggested that virulent bacteria, which can grow rapidly in serum, must possess a specific mechanism for removing iron from its transferrin complex. Two strains of Escherichia coli were examined with this in mind. Strain O141, which showed inoculum-dependent growth in serum and multiplied in the mouse peritoneum, secreted iron-binding catechols into both synthetic medium and serum. One of these compounds has an association constant for iron similar to that of transferrin. Both transferrin and ethylenediamine-di-o-hydroxyphenyl acetic acid (EDDA), which have very high affinities for ferric iron, induced catechol synthesis in growing cultures of strain O111. This organism was inhibited by normal horse serum. Further work showed that traces of specific antibody inhibited catechol synthesis by O111 exposed to EDDA; therefore, the existence of this inhibitory process means that the organism can no longer obtain Fe3+, which all remains bound to transferrin in serum. In vivo, the inhibition of O111 is similar to that produced by serum in vitro. Neither phagocytosis nor killing by complement appeared to be of any significance during the first 4 h of the infections. Significantly, the purified catechol was capable of abolishing bacteriostasis in vivo. Since these results show that the production of iron-binding catechols is essential for rapid bacterial growth both in vitro and in vivo, these compounds should therefore be considered as true virulence factors. Conversely, any interference by the host with the production or activity of these compounds would constitute an important aspect of antibacterial defense. Images PMID:16558077

  14. Spinach thylakoid polyphenol oxidase isolation, activation, and properties of the native chloroplast enzyme

    SciTech Connect

    Golbeck, J.H.; Cammarata, K.V.

    1981-05-01

    Polyphenol oxidase activity (E.C. 1.14,18.1) has been found in two enzyme species isolated from thylakoid membranes of spinach chloroplasts. The proteins were released from the membrane by sonication and purified >900-fold by ammonium sulfate precipitation, gel filtration, and ion-exchange chromatography. The enzymes appear to be the tetramer and monomer of a subunit with a molecular weight of 42,500 as determined by lithium dodecyl sulfate gel electrophoresis. Sonication releases polyphenol oxidase from the membrane largely in the latent state. In the absence of added fatty acids, the isolated enzyme spontaneously, but slowly, activates with time. Purified polyphenol oxidase utilizes o-diphenols as substrates and shows no detectable levels of monophenol or p-diphenol oxidase activities. Suitable substrates include chlorogenic acid, catechol, caffeic acid, pyrogallol, and dopamine; however, the enzyme is substrate-inhibited by the last four at concentrations near their K/sub m/. A large seasonal variation in polyphenol oxidase activity may result from a decrease in enzyme content rather than inhibition of the enzyme present.

  15. Genetic diversity and species relationships in the Oryza complex and glufosinate tolerance in rice

    E-print Network

    Vaughan, Laura Kelly

    2005-08-29

    rufipogon, Oryza nivara and Oryza sativa ssp. indica samples...................... 70 3-6. SINE and MITE data for annual and perennial Oryza species................... 72 3-7. Multi-dimensional scaling (MDS) of SINE and MITE data for Oryza...-9. Phylogenetic tree of microsatellite data for Oryza sativa ssp. japonica, Oryza sativa ssp. indica, NSGC Oryza rufipogon and Oryza nivara, red rice and perennial Oryza rufipogon samples from the GS/MDS (Figure 3-4) and STRUCTURE (Figure 3-5) analysis...

  16. Acidovorax oryzae Catheter-Associated Bloodstream Infection

    PubMed Central

    Hardy, Alison; Isalska, Barbara; Williams, Simon G.; Muldoon, Eavan G.

    2014-01-01

    Acidovorax oryzae is a bacterium that has never before been reported as pathogenic in human subjects. Here we describe the first case of a successfully treated A. oryzae catheter-associated bloodstream infection in an immunocompetent patient prior to heart transplantation. PMID:25275006

  17. Germination de la semence d'Oryza sativa L. varit Cigalon en stricte anoxie ; gnralisation aux Oryza

    E-print Network

    Paris-Sud XI, Université de

    Germination de la semence d'Oryza sativa L. variété « Cigalon » en stricte anoxie ; généralisation racinaire, riz. SUMMARY Seedling growth of Oryza sativa ev.« Cigalon» under strict ano.xia ; generalization of this adaptative behaviour to all cultivated Oryza spp. The development of Oryza sativa cv. « Cigalonwas studied

  18. Transfer of bacterial blight and blast resistance from the tetraploid wild rice Oryza minuta to cultivated rice, Oryza sativa

    Microsoft Academic Search

    A. Amante-Bordeos; L. A. Sitch; R. Nelson; R. D. Dalmacio; N. P. Oliva; H. Aswidinnoor; H. Leung

    1992-01-01

    Oryza minuta J. S. Presl ex C. B. Presl is a tetraploid wild rice with resistance to several insects and diseases, including blast (caused by Pyricularia grisea) and bacterial blight (caused by Xanthomonas oryzae pv. oryzae). To transfer resistance from the wild species into the genome of cultivated rice (Oryza sativa L.), backcross progeny (BC1, BC2, and BC3) were produced

  19. New synthetic catecholate-type siderophores with triamine backbone

    Microsoft Academic Search

    Lothar Heinisch; Peter Gebhardt; Renate Heidersbach; Rolf Reissbrodt; Ute Möllmann

    2002-01-01

    New analogues of triscatecholate siderophores based on linear or tripodal triamines with or without spacer groups or lipophilic and hydrophilic substituents were synthesized. The catecholate moieties were prepared in OH-forms, as acetylated compounds or masked as 8-methoxycarbonyloxy-2,4-dioxo-1,3-benzoxazine derivatives. Some of the new compounds were active as siderophores tested by growth promotion assays using various Gram-negative bacteria and mycobacteria under iron

  20. Brain catechol synthesis - Control by brain tyrosine concentration

    NASA Technical Reports Server (NTRS)

    Wurtman, R. J.; Larin, F.; Mostafapour, S.; Fernstrom, J. D.

    1974-01-01

    Brain catechol synthesis was estimated by measuring the rate at which brain dopa levels rose following decarboxylase inhibition. Dopa accumulation was accelerated by tyrosine administration, and decreased by treatments that lowered brain tyrosine concentrations (for example, intraperitoneal tryptophan, leucine, or parachlorophenylalanine). A low dose of phenylalanine elevated brain tyrosine without accelerating dopa synthesis. Our findings raise the possibility that nutritional and endocrine factors might influence brain catecholamine synthesis by controlling the availability of tyrosine.

  1. Immobilization of Amphiphilic Polycations by Catechol Functionality for Antimicrobial Coatings

    PubMed Central

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

    2011-01-01

    A new strategy to prepare antimicrobial surfaces by a simple dip-coating procedure is reported. Amphiphilic polycations with different mole ratios of monomers containing dodecyl quaternary ammonium, methoxyethyl, and catechol groups were synthesized by free-radical polymerization. The polymer coatings were prepared by immersing glass slides into a polymer solution and subsequent drying and heating. The quaternary ammonium side chains endow the coatings with potent antibacterial activity, while the methoxyetyhyl side chains enable tuning the hydrophobic/hydrophilic balance and the catachol groups promote immobilization of the polymers into films. The polymer coated surfaces displayed bactericidal activity against Escherichia coli and Staphylococcus aureus in a dynamic contact assay and prevented accumulation of viable E. coli, S. aureus, and Acinetobacter baumannii for up to 96 hours. Atomic force microscopy (AFM) images of coating surfaces indicated that the surfaces exhibit virtually the same smoothness for all polymers except the most hydrophobic. The hydrophobic polymer without methoxyethyl side chains showed clear structuring into polymer domains, causing high surface roughness. Sum-frequency generation (SFG) vibrational spectroscopy characterization of the surface structures demonstrated that the dodecyl chains are predominantly localized at the surface-air interface of the coatings. SFG also showed that the phenyl groups of the catechols are oriented on the substrate surface. These results support our hypothesis that the adhesive or cross-linking functionality of catechol groups discourages leaching of polymers, allowing tuning of the amphiphilic balance by incorporating hydrophilic components into the polymer chains to gain potent biocidal activity. PMID:21391641

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

    PubMed Central

    2013-01-01

    Catechol is used in many industries. It can be removed from wastewater by various methods but biological processes are the most superior and commonly used technology. The SCR is a modified form of SBR used to degrade catechol. The objective of this study was to investigate the performance of SCR for biodegradation and mineralization of catechol under various inlet concentrations (630–1500 mg/L) and hydraulic retention times (HRT) (18–9 h). This study used a bench scale SCR setup to test catechol degradation. The acclimation time of biomass for catechol at degradation at 630 mg/L was 41 d. The SCR operating cycle time was 6 h and the consecutive times taken for aerating, settling and decanting were 4, 1.5 and 0.5 h, respectively. This study investigated the effects of inlet catechol concentration (630–1560 mg/L) and HRT (18–9 h). The average catechol removal efficiencies in steady-state conditions of 630, 930, 12954 and 1559 mg/L of catechol were 98.5%, 98.5%, 98.2% and 96.9% in terms catechol and 97.8%, 97.7%, 96.4% and 94.3% for COD, respectively. SCR with acclimated biomasses could effectively remove the catechol and the corresponding COD from wastewater with concentrations of up to 1560, at the loading rate of 5.38 kg COD/m3.d and at a HRT of up to 13 h. The HRT was determined as an important variable affecting catechol removal from wastewater. Reducing the HRT to below 13 h led to reduced removal of catechol and COD. PMID:24499534

  3. Radicals from the gas-phase pyrolysis of catechol. 2. Comparison of the pyrolysis of catechol and hydroquinone.

    PubMed

    Khachatryan, Lavrent; Asatryan, Rubik; McFerrin, Cheri; Adounkpe, Julien; Dellinger, Barry

    2010-09-23

    Formation of radicals from the pyrolysis of catechol (CT) and hydroquinone (HQ) over a temperature range of 350-900 °C was studied using low-temperature matrix isolation electron paramagnetic resonance (LTMI EPR) spectroscopy. Comparative analysis of the pyrolysis mechanisms of these isomeric compounds was performed, and the role of semiquinone-type carrier radicals was studied. Pathways of unimolecular decomposition of intermediate radicals and molecular products were identified from the examination of the potential energy surface of catechol calculated at B3LYP hybrid density functional theory and composite CBS-QB3 levels. The results were compared with the experimental observations and mechanistic pathways previously developed for the pyrolysis of hydroquinone. PMID:20731470

  4. Distribution of the related weevil species Sitophilus oryzae and S. zeamais in Brazil.

    PubMed

    Corrêa, Alberto S; Orlando de Oliveira, Luiz; Braga, Lucas S; Guedes, Raul Narciso C

    2013-12-01

    The genus Sitophilus (Coleoptera: Curculionidae) encompasses species of great economic importance as stored grain pests worldwide. Among these species, the maize and the rice weevils (Sitophilus zeamais and Sitophilus oryzae, respectively) are particularly important in warmer climates. These two weevils exhibit closely morphological and ecological resemblance making difficult their proper identification and recognition of their distribution in grain-producing regions. Both species are recorded in South America and particularly in Brazil, but their respective distribution and prevalence were not yet assessed in the region. Therefore, several insect samples throughout Brazil were collected and subjected to morphological identification using male genitalia and also using molecular identification with species-specific primers designed for clear recognition of both the species. The primers were designed for the specific amplification of a gene fragment of the cytochrome oxidase subunit I, which exhibited high specificity during our preliminary experiments with insects from six populations of known species (either S. zeamais or S. oryzae). Both identification strategies provided the same results indicating prevalence of the maize weevil S. zeamais throughout the country. Two hypotheses may explain such prevalence: (i) the likely host preference of S. zeamais for maize because this is the most cultivated cereal in Brazil, and (ii) the prevalence of S. zeamais in tropical regions as compared with S. oryzae, which is more disseminated in subtropical and temperate regions. PMID:23956213

  5. NADPH oxidases and cancer.

    PubMed

    Roy, Krishnendu; Wu, Yongzhong; Meitzler, Jennifer L; Juhasz, Agnes; Liu, Han; Jiang, Guojian; Lu, Jiamo; Antony, Smitha; Doroshow, James H

    2015-06-01

    The mechanism by which reactive oxygen species (ROS) are produced by tumour cells remained incompletely understood until the discovery over the last 15 years of the family of NADPH oxidases (NOXs 1-5 and dual oxidases DUOX1/2) which are structural homologues of gp91phox, the major membrane-bound component of the respiratory burst oxidase of leucocytes. Knowledge of the roles of the NOX isoforms in cancer is rapidly expanding. Recent evidence suggests that both NOX1 and DUOX2 species produce ROS in the gastrointestinal tract as a result of chronic inflammatory stress; cytokine induction (by interferon-?, tumour necrosis factor ?, and interleukins IL-4 and IL-13) of NOX1 and DUOX2 may contribute to the development of colorectal and pancreatic carcinomas in patients with inflammatory bowel disease and chronic pancreatitis, respectively. NOX4 expression is increased in pre-malignant fibrotic states which may lead to carcinomas of the lung and liver. NOX5 is highly expressed in malignant melanomas, prostate cancer and Barrett's oesophagus-associated adenocarcinomas, and in the last it is related to chronic gastro-oesophageal reflux and inflammation. Over-expression of functional NOX proteins in many tissues helps to explain tissue injury and DNA damage from ROS that accompany pre-malignant conditions, as well as elucidating the potential mechanisms of NOX-related damage that contribute to both the initiation and the progression of a wide range of solid and haematopoietic malignancies. PMID:25818486

  6. NADH oxidase of plasma membranes

    Microsoft Academic Search

    D. James Morré; Andrew O. Brightman

    1991-01-01

    NADH oxidase is a cyanide-resistant and hormone-responsive oxidase intrinsic to the plasma membrane of both plant and animal cells. The activity has many unique characteristics that distinguish it from other oxidases and oxidoreductases of both organelles and internal membranes and from other oxidoreductases of the plasma membrane. Among these are resistance to inhibition by cyanide, catalase, superoxide dismutase, and phenylchloromer-curibenzoate.

  7. Phenol oxidase activity in secondary transformed peat-moorsh soils

    NASA Astrophysics Data System (ADS)

    Sty?a, K.; Szajdak, L.

    2009-04-01

    The chemical composition of peat depends on the geobotanical conditions of its formation and on the depth of sampling. The evolution of hydrogenic peat soils is closely related to the genesis of peat and to the changes in water conditions. Due to a number of factors including oscillation of ground water level, different redox potential, changes of aerobic conditions, different plant communities, and root exudes, and products of the degradation of plant remains, peat-moorsh soils may undergo a process of secondary transformation conditions (Sokolowska et al. 2005; Szajdak et al. 2007). Phenol oxidase is one of the few enzymes able to degrade recalcitrant phenolic materials as lignin (Freeman et al. 2004). Phenol oxidase enzymes catalyze polyphenol oxidation in the presence of oxygen (O2) by removing phenolic hydrogen or hydrogenes to from radicals or quinines. These products undergo nucleophilic addition reactions in the presence or absence of free - NH2 group with the eventual production of humic acid-like polymers. The presence of phenol oxidase in soil environments is important in the formation of humic substances a desirable process because the carbon is stored in a stable form (Matocha et al. 2004). The investigations were carried out on the transect of peatland 4.5 km long, located in the Agroecological Landscape Park host D. Chlapowski in Turew (40 km South-West of Pozna?, West Polish Lowland). The sites of investigation were located along Wysko? ditch. The following material was taken from four chosen sites marked as Zbechy, Bridge, Shelterbelt and Hirudo in two layers: cartel (0-50cm) and cattle (50-100cm). The object of this study was to characterize the biochemical properties by the determination of the phenol oxidize activity in two layers of the four different peat-moors soils used as meadow. The phenol oxidase activity was determined spectrophotometrically by measuring quinone formation at ?max=525 nm with catechol as substrate by method of Perucci et al. (2000). In peat the highest activities of phenol oxidase was observed in the combinations marked as Shelterbelt and whereas the lowest - in Zbechy, Bridge and Hirudo. Activities of this enzyme in peat ranged from 15.35 to 38.33 ?mol h-1g d.m soil. Increased activities of phenol oxidase have been recorded on the depth 50-100cm - catotelm (21.74-38.33 ?mol h-1g d.m soil) in comparison with the depth 0-50cm - acrotelm (15.35-28.32 ?mol h-1g d.m soil). References Freeman, C., Ostle N.J., Fener, N., Kang H. 2004. A regulatory role for phenol oxidase during decomposition in peatlands. Soil Biology and Biochemistry, 36, 1663-1667. Matocha Ch.J., Haszler G.R., Grove J.H. 2004. Nitrogen fertilization suppresses soil phenol oxidase enzyme activity in no-tillage systems. Soil Science, 169/10, 708-714. Perucci P., Casucci C., Dumontet S. 2000. An improved method to evaluate the o-diphenol oxidase activity of soil. Soil Biology and Biochemistry, 32, 1927-1933. Sokolowska Z., Szajdak L., Matyka-Sarzy?ska D. 2005. Impact of the degree of secondary transformation on amid-base properties of organic compounds in mucks. Geoderma, 127, 80-90. Szajdak L., Szczepa?ski M., Bogacz A. 2007. Impact of secondary transformation of peat-moorsh soils on the decrease of nitrogen and carbon compounds in ground water. Agronomy Research, 5/2, 189-200.

  8. Lysyl oxidases: a novel multifunctional amine oxidase family.

    PubMed

    Csiszar, K

    2001-01-01

    Lysyl oxidase (LOX), a copper-containing amine oxidase, belongs to a heterogeneous family of enzymes that oxidize primary amine substrates to reactive aldehydes. LOX has been traditionally known for one function, the extracellular catalysis of lysine-derived cross-links in fibrillar collagens and elastin. More recently, diverse roles have been attributed to lysyl oxidase and these novel activities cover a spectrum of diverse biological functions such as developmental regulation, tumor suppression, cell motility, and cellular senescence. Lysyl oxidase has also been shown to have both intracellular and intranuclear locations. The multifunctional properties of lysyl oxidase (LOX) and our recent discovery of three novel members of this amine oxidase family, LOX-like (LOXL), LOXL2, and LOXL3, indicate the possibility that these varied functions are performed in both intracellular and extracellular environments by individual novel members of the LOX amine-oxidase family. Structural similarities of the highly conserved copper-binding and lysyl-tyrosylquinone cofactor sites among the LOX and LOX-like proteins may result in similar amine oxidase activities. However, specific novel functions, such as a potential role in cell adhesion and cell growth control, will be determined by other, conserved domains such as the cytokine receptor-like domain that is shared by all LOXs and by multiple scavenger receptor cysteine-rich (SRCR) domains present in LOXL2 and LOXL3. Furthermore, these functions may be carried out in a temporally and spatially regulated fashion. PMID:11642359

  9. Adsorptive removal of aniline by granular activated carbon from aqueous solutions with catechol and resorcinol

    Microsoft Academic Search

    S. Suresh; V. C. Srivastava; I. M. Mishra

    2012-01-01

    In the present paper, the removal of aniline by adsorption process onto granular activated carbon (GAC) is reported from aqueous solutions containing catechol and resorcinol separately. The Taguchi experimental design was applied to study the effect of such parameters as the initial component concentrations (C0, i) of two solutes (aniline and catechol or aniline and resorcinol) in the solution, temperature

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

    PubMed Central

    Klitsche, Franziska; Ramcke, Julian; Migenda, Julia; Hensel, Andreas; Vossmeyer, Tobias; Weller, Horst

    2015-01-01

    Summary 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.

  11. CCMR: The Synthesis of Covalent Organic Frameworks From Acetonide-Protected Polyfunctional Catechols.

    NSDL National Science Digital Library

    White, Sarah L.

    2009-08-15

    The formation and exchange of boronate ester moieties associated with the synthesis of boronate ester-linked covalent organic frameworks (COFs) has been investigated from acetonide-protected catechol and phenylboronic acid starting materials. Acetonideprotected catechol reacts with phenylboronic acid in the presence of the Lewis acid boron triflouride etherate (BF3OEt2) to afford the corresponding catechol boronic ester. Catechol phenylboronate undergoes exchange in the presence of BF3OEt2 with excess boronic acid or catechol, both important processes for the formation of well-ordered COF materials. These mechanistic studies were used to optimize the reaction of acetonideprotected 2,3,6,7,10,11-hexahydroxytriphenylene with bis(boronic) acids to provide crystalline samples of two previously reported COFs, indicating the utility of this new synthetic method for the preparation of these materials.

  12. Improved performance of protected catecholic polysiloxanes for bio-inspired wet adhesion to surface oxides

    PubMed Central

    Heo, Jinhwa; Kang, Taegon; Jang, Se Gyu; Hwang, Dong Soo; Spruell, Jason M.; Killops, Kato L.; Waite, J. Herbert; Hawker, Craig J.

    2012-01-01

    A facile synthetic strategy for introducing catecholic moieties into polymeric materials based on a readily available precursor – eugenol – and efficient chemistries – tris(pentafluorophenyl)borane catalyzed silation and thiol-ene coupling is reported. Silyl-protection is shown to be critical for the oxidative stability of catecholic moieties during synthesis and processing which allows functionalized polysiloxane derivatives to be fabricated into 3-D microstructures as well as 2-D patterned surfaces. Deprotection gives stable catechol surfaces with adhesion to a variety of oxide surfaces being precisely tuned by the level of catechol incorporation. The advantage of silyl-protection for catechol functionalized polysiloxanes is demonstrated and represents a promising and versatile new platform for underwater surface treatments. PMID:23181614

  13. Mapping the conformational space accessible to catechol-O-methyltransferase

    PubMed Central

    Ehler, Andreas; Benz, Jörg; Schlatter, Daniel; Rudolph, Markus G.

    2014-01-01

    Methylation catalysed by catechol-O-methyltransferase (COMT) is the main pathway of catechol neurotransmitter deactivation in the prefrontal cortex. Low levels of this class of neurotransmitters are held to be causative of diseases such as schizophrenia, depression and Parkinson’s disease. Inhibition of COMT may increase neurotransmitter levels, thus offering a route for treatment. Structure-based drug design hitherto seems to be based on the closed enzyme conformation. Here, a set of apo, semi-holo, holo and Michaelis form crystal structures are described that define the conformational space available to COMT and that include likely intermediates along the catalytic pathway. Domain swaps and sizeable loop movements around the active site testify to the flexibility of this enzyme, rendering COMT a difficult drug target. The low affinity of the co-substrate S-adenosylmethionine and the large conformational changes involved during catalysis highlight significant energetic investment to achieve the closed conformation. Since each conformation of COMT is a bona fide target for inhibitors, other states than the closed conformation may be promising to address. Crystallographic data for an alternative avenue of COMT inhibition, i.e. locking of the apo state by an inhibitor, are presented. The set of COMT structures may prove to be useful for the development of novel classes of inhibitors. PMID:25084335

  14. Methyl conjugation in uraemia: catechol-O-methyltransferase.

    PubMed Central

    Pazmiño, P A; Weinshilboum, R M

    1980-01-01

    1 Erythrocyte (RBC) catechol-9-methyltransferase (COMT) activity is significantly higher in erythrocytes from uraemic patients on maintenance haemodialysis, 18.7 +/- 1.4 units/ml RBC (mean +/- s.e. mean, n = 22) than in the blood of randomly selected subjects, 12.0 +/- 0.2 units/ml (mean +/- s.e. mean, n = 557, P < 0.001). 2 Uraemic plasma contains larger quantities of endogenous methyl acceptors than does normal plasma, and it reversibly inhibits RBC lysate COMT activity to a greater degree than does normal plasma. 3 There are large individual variations in the degree of inhibition of RBC COMT activity plasma from patients with renal failure. Inhibition varied from 10-43% when 40 microliters plasma from each of 19 randomly selected uraemic patients was tested, and there as a direct correlation between the inhibition of COMT by plasma from an individual uraemic patient and its content of endogenous methyl acceptors (r = 0.64, n = 19, P < 0.01). 4 Kinetic studies with pooled uraemic plasma demonstrate that inhibition of COMT by uraemic plasma is uncompetitive with respect to both the catechol substrate and the methyl donor for the reaction, S-adenosyl-L-methionine. 5 Plasma from uraemic patients does not inhibit partially purified rat liver COMT, an observation which suggests that the inhibition is not due to a direct effect on COMT but requires the presence of other constituents of the RBC lysate, perhaps other methyltransferase enzymes. PMID:7437264

  15. Detoxication of Structurally Diverse Polycyclic Aromatic Hydrocarbon (PAH) o-Quinones by Human Recombinant Catechol-O-methyltransferase (COMT) via O-Methylation of PAH Catechols*

    PubMed Central

    Zhang, Li; Jin, Yi; Chen, Mo; Huang, Meng; Harvey, Ronald G.; Blair, Ian A.; Penning, Trevor M.

    2011-01-01

    Polycyclic aromatic hydrocarbons (PAH) are environmental and tobacco carcinogens. Metabolic activation of intermediate PAH trans-dihydrodiols by aldo-keto reductases (AKRs) leads to the formation of electrophilic and redox-active o-quinones. We investigated whether O-methylation by human recombinant soluble catechol-O-methyltransferase (S-COMT) is a feasible detoxication step for a panel of structurally diverse PAH-catechols produced during the redox-cycling process. Classes of PAH non-K-region o-quinones (bay region, methylated bay region, and fjord region o-quinones) produced by AKRs were employed in the studies. PAH o-quinones were reduced to the corresponding catechols by dithiothreitol under anaerobic conditions and then further O-methylated by human S-COMT in the presence of S-[3H]adenosyl-l-methionine as a methyl group donor. The formation of the O-methylated catechols was detected by HPLC-UV coupled with in-line radiometric detection, and unlabeled products were also characterized by LC-MS/MS. Human S-COMT was able to catalyze O-methylation of all of the PAH-catechols and generated two isomeric metabolites in different proportions. LC-MS/MS showed that each isomer was a mono-O-methylated metabolite. 1H NMR was used to assign the predominant positional isomer of benzo[a]pyrene-7,8-catechol as the O-8-monomethylated catechol. The catalytic efficiency (kcat/Km) varied among different classes of PAH-catechols by 500-fold. The ability of S-COMT to produce two isomeric products from PAH-catechols was rationalized using the crystal structure of the enzyme. We provide evidence that O-8-monomethylated benzo[a]pyrene-7,8-catechol is formed in three different human lung cell lines. It is concluded that human S-COMT may play a critical role in the detoxication of PAH o-quinones generated by AKRs. PMID:21622560

  16. Epidemiology / pidmiologie Spatial distribution of Rhizoctonia oryzae and

    E-print Network

    Zhang, Hao

    Epidemiology / Épidémiologie Spatial distribution of Rhizoctonia oryzae and rhizoctonia root rot in direct-seeded cereals T.C. Paulitz, H. Zhang, and R.J. Cook Abstract: Rhizoctonia oryzae causes root rot Rhizoctonia oryzae cause le rhizoctone noir et l'arrêt de croissance chez le blé, l'orge et d'autres petites

  17. Draft Genome Sequence of Aspergillus oryzae Strain 3.042

    PubMed Central

    Zhao, Guozhong; Yao, Yunping; Qi, Wei; Wang, Chunling; Hou, Lihua; Zeng, Bin

    2012-01-01

    Aspergillus oryzae is the most important fungus for the traditional fermentation in China and is particularly important in soy sauce fermentation. We report the 36,547,279-bp draft genome sequence of A. oryzae 3.042 and compared it to the published genome sequence of A. oryzae RIB40. PMID:22933657

  18. Compositional Difference of the Exopolysaccharides Produced by the Virulent and Virulence-Deficient Strains of Xanthomonas oryzae pv. oryzae

    Microsoft Academic Search

    Ashok Kumar; R. Sunish Kumar; N. Sakthivel

    2003-01-01

    Xanthomonas oryzae pv. oryzae, the bacterial blight pathogen of rice, is known to produce phytotoxic polysaccharides. The extracellular polysaccharide (EPS)\\u000a was isolated from virulent (BXO1) and virulence-deficient gum G mutant (BXO1002) strains of X. oryzae pv. oryzae and characterized using fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR). Data from the FT-IR suggested\\u000a that the aldehyde (R-CHO) group and

  19. ?-cyclodextrin-cobalt ferrite nanocomposite as enhanced sensing platform for catechol determination.

    PubMed

    Han, Jin-Tu; Huang, Ke-Jing; Li, Jing; Liu, Yan-Ming; Yu, Meng

    2012-10-01

    An electrochemical sensor based on ?-cyclodextrin-cobalt ferrite nanocomposite was developed for the sensitive detection of catechol (CT). To construct the base of the sensor, a novel composite was initially fabricated and used as the substrate material by combining cobalt ferrite nanocomposite and ?-cyclodextrin via a simple sonication-induced assembly. Due to the high catechol-loading capacity on the electrode surface and the upstanding electric conductivity of cobalt ferrite nanocomposite, the electrochemical response of the fabricated sensor was greatly enhanced and displayed excellent analytical performance for catechol detection from 1 to 200 ?M with a low detection limit of 0.12 ?M (S/N=3). Moreover, the developed electrochemical sensor exhibited good selectivity and acceptable reproducibility and could be used for the detection of catechol in water samples. PMID:22659205

  20. H-point curve isolation method for determination of catechol in complex unknown mixtures

    NASA Astrophysics Data System (ADS)

    Hasani, Masoumeh; Mohammadi, Masoumeh; Shariati-Rad, Masoud; Abdollahi, Hamid

    2012-10-01

    In this work, the combination of H-point curve isolation method (HPCIM) and H-point standard additions method (HPSAM) was used for determination of catechol in the presence of phenolic interferents. Spectrophotometric multivariate calibration data constructed by successive standard additions of an analyte in an unknown matrix was used by the method. A cumulative spectrum for interferents in sample was extracted by HPCIM and then HPSAM is used for determination of the catechol concentration by obtained cumulative interferents spectrum. The method was tested with simulated data set. The spectrum obtained from applying HPCIM to the simulated data well agrees with the cumulative spectra of the interferents. The method was applied to the determination of catechol in the presence of highly overlapping interferents in synthetic ternary mixtures using spectrophotometric data. Moreover, the proposed method was successfully used for determination of catechol in real complicated matrices of tea and urine samples. Percent recoveries were between 95.4 and 113.6.

  1. NADPH Oxidases in Vascular Pathology

    PubMed Central

    Konior, Anna; Schramm, Agata; Czesnikiewicz-Guzik, Marta

    2014-01-01

    Abstract Significance: Reactive oxygen species (ROS) play a critical role in vascular disease. While there are many possible sources of ROS, nicotinamide adenine dinucleotide phosphate (NADPH) oxidases play a central role. They are a source of “kindling radicals,” which affect other enzymes, such as nitric oxide synthase endothelial nitric oxide synthase or xanthine oxidase. This is important, as risk factors for atherosclerosis (hypertension, diabetes, hypercholesterolemia, and smoking) regulate the expression and activity of NADPH oxidases in the vessel wall. Recent Advances: There are seven isoforms in mammals: Nox1, Nox2, Nox3, Nox4, Nox5, Duox1 and Duox2. Nox1, Nox2, Nox4, and Nox5 are expressed in endothelium, vascular smooth muscle cells, fibroblasts, or perivascular adipocytes. Other homologues have not been found or are expressed at very low levels; their roles have not been established. Nox1/Nox2 promote the development of endothelial dysfunction, hypertension, and inflammation. Nox4 may have a role in protecting the vasculature during stress; however, when its activity is increased, it may be detrimental. Calcium-dependent Nox5 has been implicated in oxidative damage in human atherosclerosis. Critical Issues: NADPH oxidase-derived ROS play a role in vascular pathology as well as in the maintenance of normal physiological vascular function. We also discuss recently elucidated mechanisms such as the role of NADPH oxidases in vascular protection, vascular inflammation, pulmonary hypertension, tumor angiogenesis, and central nervous system regulation of vascular function and hypertension. Future Directions: Understanding the role of individual oxidases and interactions between homologues in vascular disease is critical for efficient pharmacological regulation of vascular NADPH oxidases in both the laboratory and clinical practice. Antioxid. Redox Signal. 20, 2794–2814. PMID:24180474

  2. Surface water enhances the uptake and photoreactivity of gaseous catechol on solid iron(III) chloride.

    PubMed

    Tofan-Lazar, Julia; Al-Abadleh, Hind A

    2014-01-01

    Uptake and photoreactivity of catechol-Fe complexes are investigated at the gas/solid interface under humid and dry conditions, along with the nature of the hydrogen-bonding network of adsorbed water. Catechol was chosen as a simple model for organics in aerosols. Iron chloride was used to distinguish ionic mobility from binding to coordinated iron(III) in hematite. Studies were conducted using diffuse reflectance infrared Fourier transform spectroscopy as a function of irradiation time. Results show that adsorbed water at 30% relative humidity (RH), not light, increases the concentration of adsorbed catechol by a factor of 3 over 60 min relative to dry conditions. Also, our data show that, at 30% RH and under light and dark conditions, growth factors describing the concentration of adsorbed catechol are very similar suggesting that light does not significantly enhance the uptake of catechol vapor on FeCl3. Surface water also enhances the initial photodecay kinetics of catechol-Fe complexes at 30% RH by a factor of 10 relative to control experiments (RH < 1%, or no FeCl3 under humid conditions). Absorptions assigned to carbonyl groups were not observed with irradiation time, which was explained by the dominance of FeCl(2+) species relative to FeOH(2+) in the highly acidic "quasi-liquid" phase at 30% RH. Clear differences in the hydrogen-bonding network upon gaseous catechol uptake are observed in the dark and light and during the photodecay of adsorbed catechol. The implications of these results on our understanding of interfacial processes in aged iron-containing surfaces are discussed. PMID:24295105

  3. Role of catechol in the radical reduction of B-alkylcatecholboranes in presence of methanol.

    PubMed

    Povie, Guillaume; Villa, Giorgio; Ford, Leigh; Pozzi, Davide; Schiesser, Carl H; Renaud, Philippe

    2010-02-01

    Mechanistic investigations on the previously reported reduction of B-alkylcatecholboranes in the presence of methanol led to the disclosure of a new mechanism involving catechol as a reducing agent. More than just revising the mechanism of this reaction, we disclose here the surprising role of catechol, a chain breaking antioxidant, which becomes a source of hydrogen atoms in an efficient radical chain process. PMID:20087526

  4. Isothermal vapor–liquid equilibria for mixtures of 4-methoxyphenol, catechol, and p-cresol

    Microsoft Academic Search

    Shou-Ming Hwang; Ming-Jer Lee; Ho-mu Lin

    2000-01-01

    Isothermal vapor–liquid equilibrium data are measured with a static apparatus for the binary and ternary mixtures composed of 4-methoxyphenol, catechol (1,2-dihydroxybenzene ), and p-cresol (4-methylphenol) at temperatures ranging from 423.15 to 453.15K. While minimum pressure azeotropes are exhibited in 4-methoxyphenol+catechol, no azeotropes are found in the rest of the systems. The new binary data are correlated with the Wilson, the

  5. Purification and characterization of polyphenol oxidase from jackfruit ( Artocarpus heterophyllus ) bulbs.

    PubMed

    Tao, Yi-Ming; Yao, Le-Yi; Qin, Qiu-Yan; Shen, Wang

    2013-12-26

    Polyphenol oxidase (PPO) from jackfruit bulb was purified through acetone precipitation, ion-exchange column, and gel filtration column. PPO was a dimer with the molecular weight of 130 kDa determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and gel filtration. The Km was 8.3 and 18.2 mM using catechol and 4-methylcatechol as substrates, respectively. The optimum pH was 7.0 (catechol as the substrate) or 6.5 (4-methylcatechol as the substrate). The optimum temperature was 8 °C. The enzyme was stable below 40 °C. The activation energy (Ea) of heat inactivation was estimated to be 103.30 kJ/mol. The PPO activity was activated by Mn(2+), SDS, Tween-20, Triton X-100, citric acid, and malic acid but inhibited by K(+), Zn(2+), Mg(2+), Ca(2+), Ba(2+), cetyl trimethyl ammonium bromide (CTAB), kojic acid, tropolone, glutathione (GSH), cysteine (Cys), and ascorbic acid (AA). Cys and AA were effective to reduce browning of jackfruit bulbs during the storage at 8 °C for 15 days. PMID:24325285

  6. Alkali and halide-resistant catalysis by the multipotent oxidase from Marinomonas mediterranea.

    PubMed

    Jimenez-Juarez, Nuria; Roman-Miranda, Rosa; Baeza, Alejandro; Sánchez-Amat, Antonio; Vazquez-Duhalt, Rafael; Valderrama, Brenda

    2005-04-20

    The incorporation of fungal laccases into novel applications has been delayed mainly due to their intrinsic sensitivity towards halides and alkaline conditions. In order to explore new sources of enzymes we evaluated the multipotent polyphenol oxidase PPO1 from the marine bacterium Marinomonas mediterranea. Here we report that, in contrast to its fungal counterparts, PPO1 remained functional above neutral pH presenting high specificity for phenolic compounds, in particular for methoxyl-substituted mono-phenols and catechols. These properties, in addition to its tolerance towards chloride (up to 1 M) and its elevated redox potential at neutral pH (0.9 V), suggest this enzyme may be an interesting candidate for specific applications such as the Amperometric determination of phenolic compounds and bio-fuel cells. PMID:15831249

  7. Mono- and dinuclear manganese(III) complexes showing efficient catechol oxidase activity: syntheses, characterization and spectroscopic studies.

    PubMed

    Banu, Kazi Sabnam; Chattopadhyay, Tanmay; Banerjee, Arpita; Mukherjee, Madhuparna; Bhattacharya, Santanu; Patra, Goutam Kumar; Zangrando, Ennio; Das, Debasis

    2009-10-28

    Four side-off compartmental ligands L1-L4 [L1 = N,N'-ethylenebis(3-formyl-5-methyl-salicylaldimine), L2 = N,N'-1-methylethylenebis(3-formyl-5-methylsalicylaldimine), L3 = N,N'-1,1-dimethylethylenebis(3-formyl-5-methylsalicylaldimine) and L4= N,N'-cyclohexenebis(3-formyl-5-methylsalicylaldimine)] having two binding sites, N2O2 and O4, have been chosen to synthesize mononuclear and dinuclear manganese(III) complexes with the aim to study their catecholase activity using 3,5-di-tert-butylcatechol (3,5-DTBC) as substrate in the presence of molecular oxygen. In all cases only mononuclear manganese complexes (1-4) were obtained, with manganese coordination taking place at the N2O2 binding site only, irrespective of the amount of manganese salt used. All these complexes have been characterized by routine physico-chemical techniques. Complex MnL2Cl.4H2O (2) has further been structurally characterized by X-ray single crystal structure analysis. Four dinuclear manganese complexes, 5-8, were obtained after condensing the two pending formyl groups on each ligand (L1-L4) with aniline followed by reaction with MnCl2 to put the second Mn atom onto another N2O2 site. The catalytic activity of all complexes 1-8 has been investigated following the oxidation of 3,5-di-tert-butylcatechol (3,5-DTBC) to 3,5-di-tert-butylbenzoquinone (3,5-DTBQ) with molecular oxygen in two different solvents, methanol and acetonitrile. The study reveals that the catalytic activity is influenced by the solvent and to a significant extent by the backbone of the diamine and the behavior seems to be related mainly to steric rather than electronic factors. Experimental data suggest that a correlation, the lower the E(1/2) value the higher the catalytic activity, can be drawn between E(1/2) and Vmax of the complexes in a particular solvent. The EPR measurements suggest that the catalytic property of the complexes is related to the metal center(s) participation rather than to a radical mechanism. PMID:19809751

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

    Microsoft Academic Search

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

    2010-01-01

    Metabolites of dopamine and norepinephrine measured in the plasma have long been associated with symptomatic severity and response to treatment in schizophrenic, bipolar and other psychiatric patients. Plasma concentrations of catecholamine metabolites are genetically regulated. The genes encoding enzymes that are involved in the synthesis and degradation of these monoamines are candidate targets for this genetic regulation. We have studied

  9. [Alternative oxidase in industrial fungi].

    PubMed

    Gu, Shuai; Liu, Qiang; He, Hao; Li, Shuang

    2015-01-01

    Filamentous fungi have been used in industrial fermentation extensively. Based on non-phosphorylating electron transport process, alternative respiration pathway (ARP) acts as an energy overflow, which can balance carbon metabolism and electron transport, allow the continuance of tricarboxylic acid cycle without the formation of ATP, and permit the turnover of carbon skeletons. Alternative respiration pathway also plays an important role in the stress response of fungi and the physiological function of conditioned pathogen. Alternative oxidase (AOX) is the terminal oxidase responsible for the activity of alternative respiration pathway, which exists widely in higher plants, parts of fungi and algae. Owing to the property that alternative oxidase (AOX) is sensitive to salicylhydroxamic acid (SHAM) and insensitive to conventional inhibitors of cytochrome respiration, alternative respiration pathway by AOX is also named as cyanide-resistant respiration (CRR). In recent years, the study of the alternative respiration pathway and alternative oxidase has been a hot topic in the area involving cellular respiration metabolism. In this review we summarized the latest research advances about the functions of alternative respiration pathway and alternative oxidase in industrial fungi. PMID:26021078

  10. Studies on the mechanism of alcohol oxidase 

    E-print Network

    Menon, Vipin

    1994-01-01

    The flavoprotein alcohol oxidase from the yeast Candida boidinii catalyzes the oxidation of primary alcohols to aidehydes with transfer of the electrons to molecular oxygen to form hydrogen peroxide. The mechanism of alcohol oxidase with beta...

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

    Microsoft Academic Search

    MATTHEW B. MESARCH; CINDY H. NAKATSU; LORING NIES

    2000-01-01

    Benzene, toluene, xylenes, phenol, naphthalene, and biphenyl are among a group of compounds that have at least one reported pathway for biodegradation involving catechol 2,3-dioxygenase enzymes. Thus, detection of the corresponding catechol 2,3-dioxygenase genes can serve as a basis for identifying and quantifying bacteria that have these catabolic abilities. Primes that can successfully amplify a 238-bp catechol 2,3-dioxygenase gene fragment

  12. Genome sequence and rapid evolution of the rice pathogen Xanthomonas oryzae pv. oryzae PXO99A

    PubMed Central

    Salzberg, Steven L; Sommer, Daniel D; Schatz, Michael C; Phillippy, Adam M; Rabinowicz, Pablo D; Tsuge, Seiji; Furutani, Ayako; Ochiai, Hirokazu; Delcher, Arthur L; Kelley, David; Madupu, Ramana; Puiu, Daniela; Radune, Diana; Shumway, Martin; Trapnell, Cole; Aparna, Gudlur; Jha, Gopaljee; Pandey, Alok; Patil, Prabhu B; Ishihara, Hiromichi; Meyer, Damien F; Szurek, Boris; Verdier, Valerie; Koebnik, Ralf; Dow, J Maxwell; Ryan, Robert P; Hirata, Hisae; Tsuyumu, Shinji; Won Lee, Sang; Ronald, Pamela C; Sonti, Ramesh V; Van Sluys, Marie-Anne; Leach, Jan E; White, Frank F; Bogdanove, Adam J

    2008-01-01

    Background Xanthomonas oryzae pv. oryzae causes bacterial blight of rice (Oryza sativa L.), a major disease that constrains production of this staple crop in many parts of the world. We report here on the complete genome sequence of strain PXO99A and its comparison to two previously sequenced strains, KACC10331 and MAFF311018, which are highly similar to one another. Results The PXO99A genome is a single circular chromosome of 5,240,075 bp, considerably longer than the genomes of the other strains (4,941,439 bp and 4,940,217 bp, respectively), and it contains 5083 protein-coding genes, including 87 not found in KACC10331 or MAFF311018. PXO99A contains a greater number of virulence-associated transcription activator-like effector genes and has at least ten major chromosomal rearrangements relative to KACC10331 and MAFF311018. PXO99A contains numerous copies of diverse insertion sequence elements, members of which are associated with 7 out of 10 of the major rearrangements. A rapidly-evolving CRISPR (clustered regularly interspersed short palindromic repeats) region contains evidence of dozens of phage infections unique to the PXO99A lineage. PXO99A also contains a unique, near-perfect tandem repeat of 212 kilobases close to the replication terminus. Conclusion Our results provide striking evidence of genome plasticity and rapid evolution within Xanthomonas oryzae pv. oryzae. The comparisons point to sources of genomic variation and candidates for strain-specific adaptations of this pathogen that help to explain the extraordinary diversity of Xanthomonas oryzae pv. oryzae genotypes and races that have been isolated from around the world. PMID:18452608

  13. Recognition of Ferric Catecholates by FepA

    PubMed Central

    Annamalai, Rajasekaran; Jin, Bo; Cao, Zhenghua; Newton, Salete M. C.; Klebba, Phillip E.

    2004-01-01

    Escherichia coli FepA transports certain catecholate ferric siderophores, but not others, nor any noncatecholate compounds. Direct binding and competition experiments demonstrated that this selectivity originates during the adsorption stage. The synthetic tricatecholate Fe-TRENCAM bound to FepA with 50- to 100-fold-lower affinity than Fe-enterobactin (FeEnt), despite an identical metal center, and Fe-corynebactin only bound at much higher concentrations. Neither Fe-agrobactin nor ferrichrome bound at all, even at concentrations 106-fold above the Kd. Thus, FepA only adsorbs catecholate iron complexes, and it selects FeEnt among even its close homologs. We used alanine scanning mutagenesis to study the contributions of surface aromatic residues to FeEnt recognition. Although not apparent from crystallography, aromatic residues in L3, L5, L7, L8, and L10 affected FepA's interaction with FeEnt. Among 10 substitutions that eliminated aromatic residues, Kd increased as much as 20-fold (Y481A and Y638A) and Km increased as much as 400-fold (Y478), showing the importance of aromaticity around the pore entrance. Although many mutations equally reduced binding and transport, others caused greater deficiencies in the latter. Y638A and Y478A increased Km 10- and 200-fold more, respectively, than Kd. N-domain loop deletions created the same phenotype: ?60-67 (in NL1) and ?98-105 (in NL2) increased Kd 10- to 20-fold but raised Km 500- to 700-fold. W101A (in NL2) had little effect on Kd but increased Km 1,000-fold. These data suggested that the primary role of the N terminus is in ligand uptake. Fluorescence and radioisotopic experiments showed biphasic release of FeEnt from FepA. In spectroscopic determinations, koff1 was 0.03/s and koff2 was 0.003/s. However, FepAY272AF329A did not manifest the rapid dissociation phase, corroborating the role of aromatic residues in the initial binding of FeEnt. Thus, the ?-barrel loops contain the principal ligand recognition determinants, and the N-domain loops perform a role in ligand transport. PMID:15150246

  14. GLUCOSE OXIDASE REDUCES OXIDATION IN FROZEN SHRIMP

    E-print Network

    role oxygen can have during storage of foods (Scott, 1958). Glucose oxidase-catalase preparations are used to carry out the net reaction: 2 glucose + oxygen glucose oxidase > 2 gluconic acid. catalase of glucose oxidase -catalase would probably be more obvious in shrimp, which were packed in transparent bags

  15. Stereoselective Hydrogen Abstraction by Galactose Oxidase

    Microsoft Academic Search

    Stefan G. Minasian; Mei M. Whittaker; James W. Whittaker

    2004-01-01

    The fungal enzyme galactose oxidase is a radical copper oxidase that catalyzes the oxidation of a broad range of primary alcohols to aldehydes. Previous mechanistic studies have revealed a large substrate deuterium kinetic isotope effect on galactose oxidase turnover whose magnitude varies systematically over a series of substituted benzyl alcohols, reflecting a change in the character of the transition state

  16. Brucella abortus strain 2308 produces brucebactin, a highly efficient catecholic siderophore.

    PubMed

    González Carreró, Manuel I; Sangari, Félix J; Agüero, Jesús; García Lobo, Juan M

    2002-02-01

    Brucella abortus is known to produce 2,3-dihydroxybenzoate (2,3-DHBA) and to use this catechol as a siderophore to grow under iron-limited conditions. In this study a mutant (BAM41) is described that is deficient in siderophore production by insertion of Tn5 in the virulent B. abortus strain 2308. This mutant was unable to grow on iron-deprived medium and its growth could not be restored by addition of 2,3-DHBA. Production of catecholic compounds by both the Brucella mutant and parental strains under iron-deprivation conditions was assayed by TLC. Two catecholic substances were identified in the supernatant of the parental strain 2308. The faster migrating spot showed the same retention factor (R(f)) as that of purified 2,3-DHBA. The mutant BAM41 overproduced 2,3-DHBA, but failed to form the slower migrating catechol. This defect could only be complemented by the addition of the slow-migrating catechol from strain 2308. The genomic region containing Tn5 in BAM41 was cloned and the position of the transposon was determined by nucleotide sequencing. The sequence revealed that the insertion had occurred at a gene with homology to Escherichia coli entF, a locus involved in the late steps of the biosynthesis of the complex catecholic siderophore enterobactin. Intracellular survival and growth rates of the B. abortus wild-type and entF mutant strains in mouse-derived J774 macrophages were similar, indicating that production of this siderophore was not essential in this model of infection. It is concluded that B. abortus synthesizes a previously unknown and highly efficient catecholic siderophore, different from 2,3-DHBA, for which the name brucebactin is proposed. PMID:11832499

  17. Expression and cyclic variations of catechol-O-methyl transferase in human endometrial stroma

    PubMed Central

    Salih, Sana M.; Salama, Salama A.; Fadl, Amin A.; Nagamani, Manubai; Al-Hendy, Ayman

    2015-01-01

    Objective To investigate the role of catechol-O-methyl transferase (COMT) in the regulation of estrogen metabolism in human endometrium. Design Laboratory study. Setting Academic research laboratory. Intervention(s) Immunohistochemistry was used to localize COMT protein in human endometrial tissues. Catechol-O-methyl transferase promoter–luciferace reporter gene transactivation assay was used to assess COMT promoter activity in response to estrogen and progesterone treatment in primary human endometrial stroma (pHES) cells. Catechol-O-methyl transferase protein and mRNA expression were determined by Western blot and/or real-time polymerase chain reaction. The effect of 2-methoxy estrogen treatment on DNA proliferation, B-cell lymphoma 2, and vascular epithelial growth factor protein expression were assessed by Hoechst and Western blot analyses, respectively. Main Outcome Measure(s) Catechol-O-methyl transferase protein and mRNA subcellular localization and expression in human endometrial tissues and pHES cells. Result(s) Catechol-O-methyl transferase protein expression in human endometrial tissues was up-regulated in the proliferative phase and down-regulated in the midsecretory phase of the menstrual cycle. Estrogen induced a dose-dependent increase in COMT proximal promotor–luciferace transactivation in pHES cells whereas progesterone inhibited it. Estrogen up-regulated soluble COMT protein isoform expression whereas the addition of progesterone down-regulated it in pHES cells. High doses of 2-methoxy estrogen inhibited endometrial stroma cell proliferation, and down-regulated B-cell lymphoma 2 and vascular epithelial growth factor protein expression. Conclusion(s) Catechol-O-methyl transferase expression is hormonally regulated in human endometrial stroma. Catechol-O-methyl transferase product, 2-methoxy estrogen, inhibited endometrial stroma cell proliferation and decreased vascular epithelial growth factor and B-cell lymphoma 2 protein expression. PMID:17418156

  18. Protoporphyrinogen Oxidase-Inhibiting Herbicides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Protoporphyrinogen oxidase-inhibiting herbicides (also referred to as Protox- or PPO-inhibiting herbicides) were commercialized in the 1960s and their market share reached approximately 10% (total herbicide active ingredient output) in the late 1990’s. The wide-spread adoption of glyphosate-resista...

  19. The genome sequence of Xanthomonas oryzae pathovar oryzae KACC10331, the bacterial blight pathogen of rice

    PubMed Central

    Lee, Byoung-Moo; Park, Young-Jin; Park, Dong-Suk; Kang, Hee-Wan; Kim, Jeong-Gu; Song, Eun-Sung; Park, In-Cheol; Yoon, Ung-Han; Hahn, Jang-Ho; Koo, Bon-Sung; Lee, Gil-Bok; Kim, Hyungtae; Park, Hyun-Seok; Yoon, Kyong-Oh; Kim, Jeong-Hyun; Jung, Chol-hee; Koh, Nae-Hyung; Seo, Jeong-Sun; Go, Seung-Joo

    2005-01-01

    The nucleotide sequence was determined for the genome of Xanthomonas oryzae pathovar oryzae (Xoo) KACC10331, a bacterium that causes bacterial blight in rice (Oryza sativa L.). The genome is comprised of a single, 4 941 439 bp, circular chromosome that is G + C rich (63.7%). The genome includes 4637 open reading frames (ORFs) of which 3340 (72.0%) could be assigned putative function. Orthologs for 80% of the predicted Xoo genes were found in the previously reported X.axonopodis pv. citri (Xac) and X.campestris pv. campestris (Xcc) genomes, but 245 genes apparently specific to Xoo were identified. Xoo genes likely to be associated with pathogenesis include eight with similarity to Xanthomonas avirulence (avr) genes, a set of hypersensitive reaction and pathogenicity (hrp) genes, genes for exopolysaccharide production, and genes encoding extracellular plant cell wall-degrading enzymes. The presence of these genes provides insights into the interactions of this pathogen with its gramineous host. PMID:15673718

  20. Radicals from the gas-phase pyrolysis of catechol: 1. o-Semiquinone and ipso-catechol radicals.

    PubMed

    Khachatryan, Lavrent; Adounkpe, Julien; Asatryan, Rubik; Dellinger, Barry

    2010-02-18

    The formation of environmentally persistent free radicals (EPFRs) from the gas-phase pyrolysis of catechol (CT) was studied over a temperature range of 400-750 degrees C using the technique of low-temperature matrix isolation electron paramagnetic resonance (LTMI-EPR) spectroscopy. A split singlet EPR spectrum with a g value of 2.0052 was observed. To aid in the interpretation of this spectrum, a detailed analysis of the potential energy surface of CT decomposition pathways was performed employing CBS-QB3 multilevel and DFT individual methods. The energetically favored channels were the formation of ipso- and alpha-CT isomers of CT as well as o-semiquinone (o-SQ) radicals from ipso- and alpha-CT. ipso-CT as well as open ipso-CT radicals were apparently unstable intermediates that could not be accumulated in sufficiently high concentrations to be detected by EPR. The calculated EPR spectrum of o-SQ radical is consistent with the formation of an oxygen-centered radical with a high g value observed experimentally. The hyperfine splitting of the observed spectrum can be attributed to the formation of hydrogen bonds in radical dimers. The lack of experimental observation of o-benzoquinone, an anticipated pyrolysis product, has been explained based on theoretical calculations. PMID:20104861

  1. Relation Between the Adsorbed Quantity and the Immersion Enthalpy in Catechol Aqueous Solutions on Activated Carbons

    PubMed Central

    Moreno-Piraján, Juan Carlos; Blanco, Diego; Giraldo, Liliana

    2012-01-01

    An activated carbon, CarbochemTM—PS230, was modified by chemical and thermal treatment in flow of H2, in order to evaluate the influence of the activated carbon chemical characteristics in the adsorption of the catechol. The catechol adsorption in aqueous solution was studied along with the effect of the pH solution in the adsorption process of modified activated carbons and the variation of immersion enthalpy of activated carbons in the aqueous solutions of catechol. The interaction solid-solution is characterized by adsorption isotherms analysis, at 298 K and pH 7, 9 and 11 in order to evaluate the adsorption value above and below that of the catechol pKa. The adsorption capacity of carbons increases when the solution pH decreases. The retained amount increases slightly in the reduced carbon to maximum adsorption pH and diminishes in the oxidized carbon. Similar conclusions are obtained from the immersion enthalpies, whose values increase with the solute quantity retained. In granular activated carbon (CAG), the immersion enthalpies obtained are between 21.5 and 45.7 J·g?1 for catechol aqueous solutions in a range of 20 at 1500 mg·L?1. PMID:22312237

  2. Somaclonal genetics of rice, Oryza sativa L

    Microsoft Academic Search

    Sun Zong-xiu; Zhao Cheng-zhang; Zheng Kang-le; Qi Xiu-fang; Fu Ya-ping

    1983-01-01

    The inheritance and variations of some traits of more than 2,000 somatic cell derived plants of rice (Oryza sativa L.) were investigated in the second and third generations (T2 and T3) of regenerated plants (somaclones). The percentages of multiploids occurring in somaclones ranged from 0–13.3 in nine varieties (or hybrids) of ‘Hsien’ (indica) group, but no multiploid was found in

  3. Bioconversion of Capsaicin by Aspergillus oryzae.

    PubMed

    Lee, Minji; Cho, Jeong-Yong; Lee, Yu Geon; Lee, Hyoung Jae; Lim, Seong-Il; Park, So-Lim; Moon, Jae-Hak

    2015-07-01

    This study identified metabolites of capsaicin bioconverted by Aspergillus oryzae, which is generally used for mass production of gochujang prepared by fermenting red pepper powder in Korea. A. oryzae was incubated with capsaicin in potato dextrose broth. Capsaicin decreased depending on the incubation period, but new metabolites increased. Five capsaicin metabolites purified from the ethyl acetate fraction of the capsaicin culture were identified as N-vanillylcarbamoylbutyric acid, N-vanillyl-9-hydroxy-8-methyloctanamide, ?-hydroxycapsaicin, 8-methyl-N-vanillylcarbamoyl-6(E)-octenoic acid, and 2-methyl-N-vanillylcarbamoyl-6(Z)-octenoic acid by nuclear magnetic resonance (NMR) and mass spectrometry (MS). The capsaicin metabolites in gochujang were confirmed and quantitated by selective multiple reaction monitoring detection after liquid chromatography electrospray ionization MS using the isolated compounds as external standards. On the basis of the structures of the capsaicin metabolites, it is proposed that capsaicin metabolites were converted by A. oryzae by ?-hydroxylation, alcohol oxidation, hydrogenation, isomerization, and ?- and/or ?-oxidation. PMID:26072923

  4. Gene Prioritization of Resistant Rice Gene against Xanthomas oryzae pv. oryzae by Using Text Mining Technologies

    PubMed Central

    Xia, Jingbo; Zhang, Xing; Yuan, Daojun; Chen, Lingling; Webster, Jonathan; Fang, Alex Chengyu

    2013-01-01

    To effectively assess the possibility of the unknown rice protein resistant to Xanthomonas oryzae pv. oryzae, a hybrid strategy is proposed to enhance gene prioritization by combining text mining technologies with a sequence-based approach. The text mining technique of term frequency inverse document frequency is used to measure the importance of distinguished terms which reflect biomedical activity in rice before candidate genes are screened and vital terms are produced. Afterwards, a built-in classifier under the chaos games representation algorithm is used to sieve the best possible candidate gene. Our experiment results show that the combination of these two methods achieves enhanced gene prioritization. PMID:24371834

  5. Catechol estrogens as biomarkers for mammary gland cancer.

    PubMed

    Calaf, Gloria M; Garrido, Fernando

    2011-07-01

    The origin of human tumors has been attributed to the exposure to several environmental chemicals and implicated in the increase of incidence in breast cancer. Progression of breast cancer follows a complex multistep process that seems to depend on various exogenous and endogenous factors. The aim of this study was to examine the effects of the organo-phosphorous pesticide malathion in the presence of estrogen on neoplastic transformation of rat mammary glands. Virgin female rats were sacrificed after 30, 124 and 240 days of 5-day injections twice a day. There were four groups: i) control, ii) malathion (22 mg/100 g body weight, BW), iii) 17?-estradiol (30 µg/100 g BW) and iv) combination of both. Progressive alterations in ducts were observed by the effect of malathion in comparison to control after 240 days. Ducts markedly increased in size and number of cells per square millimeter and tumors similar to ductal carcinoma were originated. The increase in number of proliferative ducts per square millimeter was significantly (P<0.05) higher in malathion-treated animals compared to the other groups. Progressive alterations in lobules with estrogen treatment were found after 240 days. Lobules became markedly abnormal, referred to as secretory lobules, increased in number and size and the tumors originated were similar to lobular carcinoma. The increase in number of secretory lobules was significantly (P<0.05) higher in estrogen- treated animals compared to the other groups. Treatment with the combination of malathion and estrogen gave rise to tumors constituted of both proliferative ducts and secretory lobules as well as formation of estrogen metabolites such as 2 and 4 catechol estrogens in the blood of the animals after 240 days. We concluded that morphological changes and alterations in the blood of the animals can be used as biomarkers for mammary gland cancer. PMID:21503573

  6. Direct Analysis of Phenol, Catechol and Hydroquinone in Human Urine by Coupled-Column HPLC with Fluorimetric Detection

    Microsoft Academic Search

    G. Marrubini; E. Calleri; T. Coccini; A. F. Castoldi; L. Manzo

    2005-01-01

    Phenol, catechol, and hydroquinone, are urinary end-products of the metabolism of benzene, nutrients, drugs, and endogenous substances. Recent research demonstrated that phenol, catechol, and hydroquinone, may have themselves a role in the carcinogenicity of benzene and in mechanisms that lead to leukemia. In this respect there is the need of rapid, low-cost, and possibly direct methods to quantitate these phenolic

  7. Effect of ?-cyclodextrin on intra and intermolecular Michael addition of some catechol derivatives.

    PubMed

    Khalafi, Lida; Rafiee, Mohammad; Fathi, Sahar

    2014-01-24

    The oxidation reactions of catechol, dopamine and epinephrine have been studied in the absence and presence of N-methylaniline by UV-Vis. Spectrophotometry. A variety of reaction pathways (inter and intramolecular reactions) that followed by this oxidation have been observed depending on the nature of catechol derivatives. The observed homogeneous rate constants of the reactions were estimated by fitting the absorption time profiles for each reaction. The effect of ?-cyclodextrin and its inclusion complex has also been studied on the chosen reactions. The formation constants of the complexes of catechol, dopamine and epinephrine with ?-cyclodextrin as well as the rate constants of the reactions of free and complexed forms have been obtained by fitting the absorption-time spectra to a proposed kinetic-equilibrium model. PMID:24096065

  8. Catechol-functionalized chitosan/pluronic hydrogels for tissue adhesives and hemostatic materials.

    PubMed

    Ryu, Ji Hyun; Lee, Yuhan; Kong, Won Ho; Kim, Taek Gyoung; Park, Tae Gwan; Lee, Haeshin

    2011-07-11

    Bioinspired from adhesion behaviors of mussels, injectable and thermosensitive chitosan/Pluronic composite hydrogels were synthesized for tissue adhesives and hemostatic materials. Chitosan conjugated with multiple catechol groups in the backbone was cross-linked with terminally thiolated Pluronic F-127 triblock copolymer to produce temperature-sensitive and adhesive sol-gel transition hydrogels. A blend mixture of the catechol-conjugated chitosan and the thiolated Pluronic F-127 was a viscous solution state at room temperature but became a cross-linked gel state with instantaneous solidification at the body temperature and physiological pH. The adhesive chitosan/Pluronic injectable hydrogels with remnant catechol groups showed strong adhesiveness to soft tissues and mucous layers and also demonstrated superior hemostatic properties. These chitosan/Pluronic hydrogels are expected to be usefully exploited for injectable drug delivery depots, tissue engineering hydrogels, tissue adhesives, and antibleeding materials. PMID:21599012

  9. Effect of ?-cyclodextrin on intra and intermolecular Michael addition of some catechol derivatives

    NASA Astrophysics Data System (ADS)

    Khalafi, Lida; Rafiee, Mohammad; Fathi, Sahar

    2014-01-01

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

  10. PLASMIDS FOR EXPRESSION OF HETEROLOGOUS PROTEINS IN RHIZOPUS ORYZAE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizopus oryzae has long been used for enzyme production (e.g., glucoamylase and lipase), organic acid synthesis, and various fermented food applications. In this work, we describe a set of plasmid-based expression vectors that can be used for the production of heterologous proteins in R. oryzae. ...

  11. Lactic acid production from xylose by the fungus Rhizopus oryzae

    Microsoft Academic Search

    Ronald H. W. Maas; Robert R. Bakker; Gerrit Eggink; Ruud A. Weusthuis

    2006-01-01

    Lignocellulosic biomass is considered nowadays to be an economically attractive carbohydrate feedstock for large-scale fermentation of bulk chemicals such as lactic acid. The filamentous fungus Rhizopus oryzae is able to grow in mineral medium with glucose as sole carbon source and to produce optically pure l(+)-lactic acid. Less is known about the conversion by R. oryzae of pentose sugars such

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

    PubMed

    Bukowska, Bo?ena; Micha?owicz, 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 500?g/mL for 1h. Human blood mononuclear cells were obtained from leucocyte-platelet buffy coat taken from healthy donors in the Blood Bank of ?ód?, 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 250?g/mL), apoptotic (from 100?g/mL), and morphological changes (from 250?g/mL) in the incubated cells. We have also noted that catechol decreased H2DCF oxidation at 2 and 10?g/mL but at higher concentrations of 250 and 500?g/mL it caused statistically significant increase in the oxidation of this probe. We also observed an increase in lipid peroxidation (from 250?g/mL) and protein carbonylation (from 50?g/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

  13. Abiotic transformation of catechol and 1-naphthol in aqueous solution-influence of environmental factors.

    PubMed

    Borraccino, R; Kharoune, M; Giot, R; Agathos, S N; Nyns, E J; Naveau, H P; Pauss, A

    2001-10-01

    The abiotic transformation of catechol and 1-naphthol singly and in mixtures was tested in sterile Tris-HCl buffer with regard to several environmental factors including temperature (7 degrees C, 20 degrees C and 30 degrees C), lighting conditions, pH (between 7.0 and 8.5) and dissolved oxygen (at partial pressures of 0.0, 220, 2200, 11000 and 22000 Pa). Irrespective of lighting conditions. catechol autoxidation was confirmed in aerated medium with a rate independent of the presence of 1-naphthol but proportional to the dissolved oxygen concentration, to the pH (its half-disappearance occurred in 24h at pH 8.5) and, to a lesser extent, to the incubating temperature (at 20 degrees C, 20% disappeared in 10 days at pH 7.0). Under alkaline conditions, the reaction of the anionic form (catecholate) with an equimolar concentration of molecular oxygen (O2) led presumably to hydrogen peroxide anion (HO2-) and coloured polymerization products. When tested alone, 1-naphthol was not significantly influenced either by lighting conditions, incubating temperature or dissolved oxygen concentration. It was also found to be quite stable with respect to pH, with a 15-fold weaker transformation rate than for catechol at the highest pH used. When tested in a mixture with catechol, 1-naphthol was found to be involved in a new chemical oxidation reaction catalyzed by catecholate. The transformation of one mole of 1-naphthol consumes four moles of oxygen. In the presence of catechol, the stoichiometry of the 1-naphthol transformation, under the influence of oxygen, suggests the possible formation of 2,5,6,8-tetrahydroxy 1,4-naphthoquinone via Lawsone (2-hydroxy 1,4-naphthoquinone) and naphthopurpurine (2,5,8-trihydroxy 1,4-naphthoquinone) as hypothetic intermediates. This is the first report of the autoxidation of 1-naphthol, catalyzed by catechol, in aqueous solution, in the absence of UV irradiation. PMID:11561636

  14. NADPH oxidases and cardiac remodelling

    Microsoft Academic Search

    Adam Nabeebaccus; Min Zhang; Ajay M. Shah

    2011-01-01

    A heart under chronic stress undergoes cardiac remodelling, a process that comprises structural and functional changes including\\u000a cardiomyocyte hypertrophy, interstitial fibrosis, contractile dysfunction, cell death and ventricular dilatation. Reactive\\u000a oxygen species (ROS)-dependent modulation of intracellular signalling is implicated in the development of cardiac remodelling.\\u000a Among the different ROS sources that are present in the heart, NADPH oxidases (NOXs) are particularly

  15. Detection of Xanthomonas oryzae pv. oryzae in artificially inoculated and naturally infected rice seeds and plants by molecular techniques

    Microsoft Academic Search

    N. Sakthivel; C. N. Mortensen; S. B. Mathur

    2001-01-01

    A polymerase chain reaction (PCR) technique was developed for detecting the presence of Xanthomonas oryzae pv. oryzae, the bacterial leaf blight (BLB) pathogen in rice seed and for studying the transmission of this bacterium from seed to plant. Primers TXT and TXT4R from an insertion sequence (IS1113) of the pathogen were used to amplify a 964-bp DNA fragment. A combined

  16. QTL mapping and introgression of yield-related traits from Oryza glumaepatula to cultivated rice ( Oryza sativa ) using microsatellite markers

    Microsoft Academic Search

    C. Brondani; P. Rangel; R. Brondani; M. Ferreira

    2002-01-01

    Rice (Oryza sativa) cultivar development currently faces the task of overcoming yield plateaus, which is difficult due to the narrow genetic base of breeding programs. Oryza glumaepatula is a diploid wild relative of cultivated rice, native to Central and South America, and is therefore a potential source of alleles of agronomic importance to rice breeding programs. We studied 11 agronomic

  17. NADPH oxidase and cardiac failure.

    PubMed

    Kuroda, Junya; Sadoshima, Junichi

    2010-08-01

    Increases in oxidative stress in the heart play an important role in mediating hypertrophy, apoptosis, fibrosis, mitochondrial dysfunction, and the consequent development of heart failure. Although it has been widely believed that electron leakage from the mitochondrial electron transport chain is the primary source of oxidative stress in the failing heart, increasing lines of evidence suggest that enzymes which produce reactive oxygen species may also contribute to it. NADPH oxidases are transmembrane enzymes dedicated to producing superoxide (O(2)(-)) by transferring an electron from NAD(P)H to molecular oxygen. Nox4 is a major NADPH oxidase isoform expressed in the heart. Nox4 is localized primarily at mitochondria in cardiac myocytes, and upregulation of Nox4 hypertrophic stimuli enhances O(2)(-) production, apoptosis, and mitochondrial dysfunction, thereby playing an important role in mediating cardiac dysfunction. Since Nox4 could be a key molecule mediating oxidative stress and pathological hypertrophy, it may serve as an important target of heart failure treatment. In this review, the importance of NADPH oxidases as sources of increased oxidative stress in the failing heart and the role of Nox4 in mediating growth and death of cardiac myocytes are discussed. PMID:20559780

  18. NADPH Oxidase and Cardiac Failure

    PubMed Central

    Kuroda, Junya; Sadoshima, Junichi

    2011-01-01

    Increases in oxidative stress in the heart play an important role in mediating hypertrophy, apoptosis, fibrosis, mitochondrial dysfunction and the consequent development of heart failure. Although it has been widely believed that electron leakage from the mitochondrial electron transport chain is the primary source of oxidative stress in the failing heart, increasing lines of evidence suggest that enzymes which produce reactive oxygen species (ROS) may also contribute to it. NADPH oxidases are transmembrane enzymes dedicated to producing superoxide (O2-) by transferring an electron from NAD(P)H to molecular oxygen. Nox4 is a major NADPH oxidase isoform expressed in the heart. Nox4 is localized primarily at mitochondria in cardiac myocytes, and upregulation of Nox4 hypertrophic stimuli enhances O2- production, apoptosis, and mitochondrial dysfunction, thereby playing an important role in mediating cardiac dysfunction. Since Nox4 could be a key molecule mediating oxidative stress and pathological hypertrophy, it may serve as an important target of heart failure treatment. In this review, the importance of NADPH oxidases as sources of increased oxidative stress in the failing heart and the role of Nox4 in mediating growth and death of cardiac myocytes are discussed. PMID:20559780

  19. Characterization of Two Brassinosteroid C-6 Oxidase Genes in Pea1[W][OA

    PubMed Central

    Jager, Corinne E.; Symons, Gregory M.; Nomura, Takahito; Yamada, Yumiko; Smith, Jennifer J.; Yamaguchi, Shinjiro; Kamiya, Yuji; Weller, James L.; Yokota, Takao; Reid, James B.

    2007-01-01

    C-6 oxidation genes play a key role in the regulation of biologically active brassinosteroid (BR) levels in the plant. They control BR activation, which involves the C-6 oxidation of 6-deoxocastasterone (6-DeoxoCS) to castasterone (CS) and in some cases the further conversion of CS to brassinolide (BL). C-6 oxidation is controlled by the CYP85A family of cytochrome P450s, and to date, two CYP85As have been isolated in tomato (Solanum lycopersicum), two in Arabidopsis (Arabidopsis thaliana), one in rice (Oryza sativa), and one in grape (Vitis vinifera). We have now isolated two CYP85As (CYP85A1 and CYP85A6) from pea (Pisum sativum). However, unlike Arabidopsis and tomato, which both contain one BR C-6 oxidase that converts 6-DeoxoCS to CS and one BR C-6 Baeyer-Villiger oxidase that converts 6-DeoxoCS right through to BL, the two BR C-6 oxidases in pea both act principally to convert 6-DeoxoCS to CS. The isolation of these two BR C-6 oxidation genes in pea highlights the species-specific differences associated with C-6 oxidation. In addition, we have isolated a novel BR-deficient mutant, lke, which blocks the function of one of these two BR C-6 oxidases (CYP85A6). The lke mutant exhibits a phenotype intermediate between wild-type plants and previously characterized pea BR mutants (lk, lka, and lkb) and contains reduced levels of CS and increased levels of 6-DeoxoCS. To date, lke is the only mutant identified in pea that blocks the latter steps of BR biosynthesis and it will therefore provide an excellent tool to further examine the regulation of BR biosynthesis and the relative biological activities of CS and BL in pea. PMID:17322341

  20. Quantitative determination of catecholic degradation products from insect sclerotized cuticles.

    PubMed

    Andersen, Svend Olav

    2008-09-01

    Acid hydrolysates of cuticle from various insect species were quantitatively analyzed for five catecholic amino acid adducts. Four of the adducts are ketocatechols; in three of them the amino acid moiety, either lysine, glycine or beta-alanine, is connected via its amino group to the alpha-carbon atom of 3,4-dihydroxyacetophenone, in the fourth a tyrosine residue is connected to the same position via its phenolic group. The fifth adduct contains histidine linked via its imidazole-ring to the beta-position of the dopamine sidechain. The three ketocatecholic adducts containing alpha-amino acids were obtained in significant yields from adult cuticles of the locust Schistocerca gregaria, the cockroaches Blaberus craniifer and Periplaneta americana, and the beetles Pachynoda sinuata and Tenebrio molitor, but only in trace amounts from larval and pupal cuticles of T. molitor, pupal cuticles of the moths Manduca sexta and Hyalophora cecropia, and puparia of the blowfly Calliphora vicina. The beta-alanine-containing ketocatechol was not obtained from cuticle of locusts and T. molitor larvae and pupae, but it was present in the hydrolysates of the other cuticles. The beta-histidine-dopamine adduct was obtained from all the cuticles, the highest yield was obtained from adult P. sinuata and the lowest yield was from adult S. gregaria. The beta-histidine-dopamine adduct is derived from the product formed by reaction of p-quinone methides of N-acetyldopamine (NADA) or N-beta-alanyldopamine (NBAD) with histidine residues in the cuticular proteins. The ketocatecholic adducts are assumed to be degradation products of crosslinks formed when oxidized dehydro-NADA reacts with the cuticular proteins. The insect species investigated appear to use both pathways for sclerotization, but to widely differing extents; the dehydro-NADA pathway dominates in cuticles which are exposed to strong deforming forces, such as those of adult locusts and cockroaches, and the p-quinone methide pathway dominates in cuticle of lepidopteran pupae and blowfly puparia, which are not exposed to strong mechanical forces but have to be effectively protected against microbial and fungal attacks. PMID:18675913

  1. Polyphenol oxidase and herbivore defense in trembling aspen (Populus tremuloides): cDNA cloning, expression, and potential substrates.

    PubMed

    Haruta, Miyoshi; Pedersen, Jens A.; Constabel, C. Peter

    2001-08-01

    The biochemical anti-herbivore defense of trembling aspen (Populus tremuloides Michx.) was investigated in a molecular analysis of polyphenol oxidase (PPO; EC 1.10.3.2). A PPO cDNA was isolated from a trembling aspen wounded leaf cDNA library and its nucleotide sequence determined. Southern analysis indicated the presence of two PPO genes in the trembling aspen genome. Expression of PPO was found to be induced after herbivory by forest tent caterpillar, by wounding, and by methyl jasmonate treatment. Wound induction was systemic, and occurred in unwounded leaves on wounded plants. This pattern of expression is consistent with a role of this enzyme in insect defense. A search for potential PPO substrates in ethanolic aspen leaf extracts using electron spin resonance (ESR) found no pre-existing diphenolic compounds. However, following a brief delay and several additions of oxygen, an ESR signal specific for catechol was detected. The source of this catechol was most likely the aspen phenolic glycosides tremulacin or salicortin which decomposed during ESR experiments. This was subsequently confirmed in experiments using pure salicortin. PMID:11473716

  2. Comparison of membrane-bound and soluble polyphenol oxidase in Fuji apple (Malus domestica Borkh. cv. Red Fuji).

    PubMed

    Liu, Fang; Zhao, Jin-Hong; Gan, Zhi-Lin; Ni, Yuan-Ying

    2015-04-15

    This study compared membrane-bound with soluble polyphenol oxidase (mPPO and sPPO, respectively) from Fuji apple. Purified mPPO and partially purified sPPO were used. mPPO was purified by temperature-induced phase partitioning and ion exchange chromatography. The specific activity of mPPO was 34.12× higher than that of sPPO. mPPO was more stable than sPPO at pH 5.0-8.5. Although mPPO was more easily inactivated at 25-55 °C, it is still more active than sPPO in this temperature range. The optimum substrate of mPPO was 4-methyl catechol, followed by catechol. L-cysteine had the highest inhibitory effects on mPPO followed by ascorbic acid and glutathione. Surprisingly, EDTA increased mPPO activity. The results revealed that purified mPPO is a dimer with a molecular weight of approximately 67 kDa. PMID:25465998

  3. Catechol-O-Methyltransferase Val158Met Polymorphism Associates with Individual Differences in Sleep

    E-print Network

    Bushman, Frederic

    baseline REM sleep latency. The genotypes, however, did not differ in performance across various executiveCatechol-O-Methyltransferase Val158Met Polymorphism Associates with Individual Differences in Sleep Physiologic Responses to Chronic Sleep Loss Namni Goel1 *, Siobhan Banks1¤ , Ling Lin2 , Emmanuel Mignot2

  4. High propylene/propane adsorption selectivity in a copper(catecholate)-decorated porous organic

    E-print Network

    High propylene/propane adsorption selectivity in a copper(catecholate)-decorated porous organic and propane isotherms measured at ambient temperatures and ideal adsorption solution theory (IAST demonstrated to be highly advantageous in a wide array of applications such as gas storage,1­3 chemical

  5. Salicylate and catechol levels are maintained in nahG transgenic poplar

    Microsoft Academic Search

    Alison M. Morse; Timothy J. Tschaplinski; Christopher Dervinis; Paula M. Pijut; Eric A. Schmelz; Wendy Day; John M. Davis

    2007-01-01

    Metabolic profiling was used to investigate the molecular phenotypes of a transgenic Populus tremula×P. alba hybrid expressing the nahG transgene, a bacterial gene encoding salicylate hydroxylase that converts salicylic acid to catechol. Despite the efficacy of this transgenic approach to reduce salicylic acid levels in other model systems and thereby elucidate roles for salicylic acid in plant signaling, transgenic poplars

  6. Mechanisms of product formation from the pyrolytic thermal degradation of catechol.

    PubMed

    Lomnicki, Slawomir; Truong, Hieu; Dellinger, Barry

    2008-09-01

    Catechol has been identified as one of the most abundant organic products in tobacco smoke and a major molecular precursor for semiquinone type radicals in the combustion of biomass material. The high-temperature gas-phase pyrolysis of catechol under hydrogen-rich and hydrogen-lean conditions was studied using a fused-silica tubular flow reactor coupled to an in-line GC/MS analytical system. Thermal degradation of catechol over temperature range of 250-1000 degrees C with a reaction time of 2.0s yielded a variety products including phenol, benzene, dibenzofuran, dibenzo-p-dioxin, phenylethyne, styrene, indene, anthracene, naphthalene, and biphenylene. Ortho-benzoquinone which is typically associated with the presence of semiquinone radicals was not observed and is proposed to be the result of fast decomposition reactions that lead to a variety of other reaction products. This is in contrast to the decomposition of hydroquinone that produced para-benzoquinone as the major product. A detailed mechanism of the degradation pathway of catechol is proposed. PMID:18640699

  7. Role of Catecholate Siderophores in Gram-Negative Bacterial Colonization of the Mouse Gut

    PubMed Central

    Pi, Hualiang; Jones, Shari A.; Mercer, Lynn E.; Meador, Jessica P.; Caughron, Joyce E.; Jordan, Lorne; Newton, Salete M.; Conway, Tyrrell; Klebba, Phillip E.

    2012-01-01

    We investigated the importance of the production of catecholate siderophores, and the utilization of their iron (III) complexes, to colonization of the mouse intestinal tract by Escherichia coli. First, a ?tonB strain was completely unable to colonize mice. Next, we compared wild type E. coli MG1655 to its derivatives carrying site-directed mutations of genes for enterobactin synthesis (?entA::Cm; strain CAT0), ferric catecholate transport (?fiu, ?fepA, ?cir, ?fecA::Cm; CAT4), or both (?fiu, ?fepA, ?fecA, ?cir, ?entA::Cm; CAT40) during colonization of the mouse gut. Competitions between wild type and mutant strains over a 2-week period in vivo showed impairment of all the genetically engineered bacteria relative to MG1655. CAT0, CAT4 and CAT40 colonized mice 101-, 105-, and 102-fold less efficiently, respectively, than MG1655. Unexpectedly, the additional inability of CAT40 to synthesize enterobactin resulted in a 1000-fold better colonization efficiency relative to CAT4. Analyses of gut mucus showed that CAT4 hyperexcreted enterobactin in vivo, effectively rendering the catecholate transport-deficient strain iron-starved. The results demonstrate that, contrary to prior reports, iron acquisition via catecholate siderophores plays a fundamental role in bacterial colonization of the murine intestinal tract. PMID:23209633

  8. Salicylate and catechol levels are maintained in nahG transgenic poplar

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Metabolic profiling was used to investigate the molecular phenotypes of transgenic Populus tremula x P. alba bybrids expressing the nahG transgene, a bacterial gene encoding salicylate hydroxylase that converts salicylic acid to catechol. Despite the efficacy of this transgenic approach to reducing...

  9. Characterization of the gene encoding an extracellular laccase of Myceliophthora thermophila and analysis of the recombinant enzyme expressed in Aspergillus oryzae.

    PubMed Central

    Berka, R M; Schneider, P; Golightly, E J; Brown, S H; Madden, M; Brown, K M; Halkier, T; Mondorf, K; Xu, F

    1997-01-01

    A genomic DNA segment encoding an extracellular laccase was isolated from the thermophilic fungus Myceliophthora thermophila, and the nucleotide sequence of this gene was determined. The deduced amino acid sequence of M. thermophila laccase (MtL) shows homology to laccases from diverse fungal genera. A vector containing the M. thermophila laccase coding region, under transcriptional control of an Aspergillus oryzae alpha-amylase gene promoter and terminator, was constructed for heterologous expression in A. oryzae. The recombinant laccase expressed in A. oryzae was purified to electrophoretic homogeneity by anion-exchange chromatography. Amino-terminal sequence data suggests that MtL is synthesized as a preproenzyme. The molecular mass was estimated to be approximately 100 to 140 kDa by gel filtration on Sephacryl S-300 and to be 85 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Carbohydrate analysis revealed that MtL contains 40 to 60% glycosylation. The laccase shows an absorbance spectrum that is typical of blue copper oxidases, with maxima at 276 and 589 nm, and contains 3.9 copper atoms per subunit. With syringaldazine as a substrate, MtL has optimal activity at pH 6.5 and retains nearly 100% of its activity when incubated at 60 degrees C for 20 min. This is the first report of the cloning and heterologous expression of a thermostable laccase. PMID:9251203

  10. Silicon-Induced Systemic Defense Responses in Perennial Ryegrass Against Infection by Magnaporthe oryzae.

    PubMed

    Rahman, Alamgir; Wallis, Christopher M; Uddin, Wakar

    2015-06-01

    Sustainable integrated disease management for gray leaf spot of perennial ryegrass may involve use of plant defense elicitors with compatible traditional fungicides to reduce disease incidence and severity. Silicon (Si) has previously been identified as a potential inducer or modulator of plant defenses against different fungal pathogens. To this end, perennial ryegrass was inoculated with the causal agent of gray leaf spot, Magnaporthe oryzae, when grown in soil that was nonamended or amended with three different levels of calcium silicate (1, 5, or 10 metric tons [t]/ha). When applied at a rate of 5 t/ha, calcium silicate was found to significantly suppress gray leaf spot in perennial ryegrass, including a significant reduction of disease incidence (39.5%) and disease severity (47.3%). Additional studies observed nonpenetrated papillae or cell-wall appositions harboring callose, phenolic autofluorogens, and lignin-associated polyphenolic compounds in grass grown in the Si-amended soil. Regarding defense-associated enzyme levels, only following infection did grass grown in Si-amended soil exhibit greater activities of peroxidase and polyphenol oxidase than equivalent inoculated control plants. Also following infection with M. oryzae, grass levels of several phenolic acids, including chlorogenic acid and flavonoids, and relative expression levels of genes encoding phenylalanine ammonia lyase (PALa and PALb) and lipoxygenase (LOXa) significantly increased in Si-amended plants compared with that of nonamended control plants. These results suggest that Si-mediated increase of host defense responses to fungal pathogens in perennial ryegrass has a great potential to be part of an effective integrated disease management strategy against gray leaf spot development. PMID:25738553

  11. Polyaniline-iron oxide nanohybrid film as multi-functional label-free electrochemical and biomagnetic sensor for catechol.

    PubMed

    Chandra, Sudeshna; Lang, Heinrich; Bahadur, Dhirendra

    2013-09-17

    Polyaniline-iron oxide magnetic nanohybrid was synthesized and characterized using various spectroscopic, microstructural and electrochemical techniques. The smart integration of Fe3O4 nanoparticles within the polyaniline (PANI) matrix yielded a mesoporous nanohybrid (Fe3O4@PANI) with high surface area (94 m(2) g(-1)) and average pore width of 12.8 nm. Catechol is quasi-reversibly oxidized to o-quinone and reduced at the Fe3O4@PANI modified electrodes. The amperometric current response toward catechol was evaluated using the nanohybrid and the sensitivity and detection limit were found to be 312 ?A ?L(-1) and 0.2 nM, respectively. The results from electrochemical impedance spectroscopy (EIS) indicated that the increased solution resistance (Rs) was due to elevated adsorption of catechol on the modified electrodes. Photoluminescence spectra showed ligand-to-metal charge transfer (LMCT) between p-? orbitals of the phenolate oxygen in catechol and the d-?* metal orbital of Fe3O4@PANI nanohybrid. Potential dependent spectroelectrochemical behavior of Fe3O4@PANI nanohybrid toward catechol was studied using UV/vis/NIR spectroscopy. The binding activity of the biomagnetic particles to catechol through Brownian relaxation was evident from AC susceptibility measurements. The proposed sensor was used for successful recovery of catechol in tap water samples. PMID:23998532

  12. Exploring excited states of Pt(ii) diimine catecholates for photoinduced charge separation.

    PubMed

    Scattergood, Paul A; Jesus, Patricia; Adams, Harry; Delor, Milan; Sazanovich, Igor V; Burrows, Hugh D; Serpa, Carlos; Weinstein, Julia A

    2015-07-14

    The intense absorption in the red part of the visible range, and the presence of a lowest charge-transfer excited state, render Platinum(ii) diimine catecholates potentially promising candidates for light-driven applications. Here, we test their potential as sensitisers in dye-sensitised solar cells and apply, for the first time, the sensitive method of photoacoustic calorimetry (PAC) to determine the efficiency of electron injection in the semiconductor from a photoexcited Pt(ii) complex. Pt(ii) catecholates containing 2,2'-bipyridine-4,4'-di-carboxylic acid (dcbpy) have been prepared from their parent iso-propyl ester derivatives, complexes of 2,2'-bipyridine-4,4'-di-C(O)O(i)Pr, (COO(i)Pr)2bpy, and their photophysical and electrochemical properties studied. Modifying diimine Pt(ii) catecholates with carboxylic acid functionality has allowed for the anchoring of these complexes to thin film TiO2, where steric bulk of the complexes (3,5-di(t)Bu-catechol vs. catechol) has been found to significantly influence the extent of monolayer surface coverage. Dye-sensitised solar cells using Pt(dcbpy)((t)Bu2Cat), 1a, and Pt(dcbpy)(pCat), 2a, as sensitisers, have been assembled, and photovoltaic measurements performed. The observed low, 0.02-0.07%, device efficiency of such DSSCs is attributed at least in part to the short excited state lifetime of the sensitisers, inherent to this class of complexes. The lifetime of the charge-transfer ML/LLCT excited state in Pt((COO(i)Pr)2bpy)(3,5-di-(t)Bu-catechol) was determined as 250 ps by picosecond time-resolved infrared spectroscopy, TRIR. The measured increase in device efficiency for 2a over 1a is consistent with a similar increase in the quantum yield of charge separation (where the complex acts as a donor and the semiconductor as an acceptor) determined by PAC, and is also proportional to the increased surface loading achieved with 2a. It is concluded that the relative efficiency of devices sensitised with these particular Pt(ii) species is governed by the degree of surface coverage. Overall, this work demonstrates the use of Pt(diimine)(catecholate) complexes as potential photosensitizers in solar cells, and the first application of photoacoustic calorimetry to Pt(ii) complexes in general. PMID:25683063

  13. Effects of Metal Oxides on a Fungal Laccase Activity and Catechol Transformation

    NASA Astrophysics Data System (ADS)

    Ahn, M.; Dec, J.; Bollag, J.

    2003-12-01

    The transformation of naturally occurring phenols to humic polymers is generally catalyzed by various phenoloxidases commonly present in soil. Some poorly crystalline metal oxides and hydroxides may also participate in these reactions. In this study, catechol (0.1 M) was incubated with a fungal laccase (950 unit/mL) in the presence of poorly crystalline minerals (ferrihydrite; 50 mg/mL: birnessite; 1 mg/mL: aluminum hydroxide; 50 mg/mL) to examine the interaction between these soil components under field conditions. Birnessite had an inhibitory effect on the laccase-mediated transformation of catechol (by up to 40%). Enzyme inhibition was possibly caused by the rapid production of humic-like polymers by birnessite. An additional inhibitory effect was caused by Manganese ion released from birnessite as it oxidized catechol (up to 70% loss in enzyme activity). In contrast to birnessite, aluminum hydroxide had an additive effect on the disappearance of catechol despite the rapid adsorption of the enzyme by this mineral (Xm=6.18? g/mg). Apparently, the adsorbed laccase retained some enzyme activity. Ferrihydrite also had an additive effect on catechol transformation. However, as compared to aluminum hydroxide, ferrihydrite adsorbed less laccase (Xm=0.89? g/mg) and more humic-like polymers. Unlike birnessite, aluminum hydroxide and ferrihydrite released negligible amounts of metal ions. In conclusion, under field conditions, phenoloxidase activity may be diminished by the presence of birnessite, but the presence of either ferrihydrite or aluminum hydroxide is less likely to inhibit enzyme activity, and may even enhance substrate transformation.

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

    PubMed

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

    1996-03-01

    Siderophores bind ferric ions and are involved in receptor-specific iron transport into bacteria. Six types of siderophores were tested against strains representing the 12 different serotypes of Actinobacillus pleuropneumoniae. Ferrichrome and bis-catechol-based siderophores showed strong growth-promoting activities for A. pleuropneumoniae in a disk diffusion assay. Most strains of A. pleuropneumoniae tested were able to use ferrichrome (21 of 22 or 95%), ferrichrome A (20 of 22 or 90%), and lysine-based bis-catechol (20 of 22 or 90%), while growth of 36% (8 of 22) was promoted by a synthetic hydroxamate, N5-acetyl-N5-hydroxy-L-ornithine tripeptide. A. pleuropneumoniae serotype 1 (strain FMV 87-682) and serotype 5 (strain 2245) exhibited a distinct yellow halo around colonies on Chrome Azurol S agar plates, suggesting that both strains can produce an iron chelator (siderophore) in response to iron stress. The siderophore was found to be neither a phenolate nor a hydroxamate by the chemical tests of Arnow and Csaky, respectively. This is the first report demonstrating the production of an iron chelator and the use of exogenous siderophores by A. pleuropneumoniae. A spermidine-based bis-catechol siderophore conjugated to a carbacephalosporin was shown to inhibit growth of A. pleuropneumoniae. A siderophore-antibiotic-resistant strain was isolated and shown to have lost the ability to use ferrichrome, synthetic hydroxamate, or catechol-based siderophores when grown under conditions of iron restriction. This observation indicated that a common iron uptake pathway, or a common intermediate, for hydroxamate- and catechol-based siderophores may exist in A. pleuropneumoniae. PMID:8975614

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

    PubMed

    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 ?M. 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

  16. Some new functions of amine oxidases

    Microsoft Academic Search

    B. Mondovì; P. Pietrangeli; L. Morpurgo; E. Masini; R. Federico; M. A. Mateescu; O. Befani; E. Agostinelli

    2003-01-01

    Two contrasting topics are examined in this account: the protective actions of amine oxidases (AOs) resulting from the elimination and\\/or modulation of the levels of polyamines and some biogenic amines, such as histamine, in anaphylactic shock and the cell damaging effect of AOs catabolic products. Other functions of the plasma copper-containing amine oxidase are considered; namely the modification of some

  17. Immunological comparison of sulfite oxidase

    SciTech Connect

    Pollock, V.; Barber, M.J. (Univ. South Florida College, Tampa (United States))

    1991-03-11

    Polyclonal antibodies (rabbit), elicited against FPLC-purified chicken and rat liver sulfite oxidase (SO), have been examined for inhibition and binding to purified chicken (C), rat (R), bovine (B), alligator (A) and shark (S) liver enzymes. Anti-CSO IgG cross-reacted with all five enzymes, with varying affinities, in the order CSO=ASO{gt}RSO{gt}BSO{gt}SSO. Anti-ROS IgG also cross-reacted with all five enzymes in the order RSO{gt}CSO=ASO{gt}BSO{gt}SSO. Anti-CSO IgG inhibited sulfite:cyt. c reductase (S:CR), sulfite:ferricyanide reductase (S:FR) and sulfite:dichlorophenolindophenol reductase (S:DR) activities of CSO to different extents (S:CR{gt}S:FR=S:DR). Similar differential inhibition was found for anti-ROS IgG and RSO S:CR, S:FR and S:DR activities. Anti-CSO IgG inhibited S:CR activities in the order CSO=ASO{much gt}SSO{gt}BSO. RSO was uninhibited. For anti-RSO IgG the inhibition order was RSO{gt}SSO{gt}BSO{gt}ASO. CSO was uninhibited. Anti-CSO and RSO IgGs partially inhibited Chlorella nitrate reductase (NR). Minor cross-reactivity was found for xanthine oxidase. Common antigenic determinants for all five SO's and NR are indicated.

  18. 21 CFR 173.130 - Carbohydrase derived from Rhizopus oryzae.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SECONDARY DIRECT FOOD ADDITIVES PERMITTED IN FOOD FOR HUMAN CONSUMPTION Enzyme Preparations and Microorganisms § 173.130 Carbohydrase derived from Rhizopus oryzae. Carbohydrase from Rhizopus...

  19. 21 CFR 173.130 - Carbohydrase derived from Rhizopus oryzae.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SECONDARY DIRECT FOOD ADDITIVES PERMITTED IN FOOD FOR HUMAN CONSUMPTION Enzyme Preparations and Microorganisms § 173.130 Carbohydrase derived from Rhizopus oryzae. Carbohydrase from Rhizopus...

  20. 21 CFR 173.130 - Carbohydrase derived from Rhizopus oryzae.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SECONDARY DIRECT FOOD ADDITIVES PERMITTED IN FOOD FOR HUMAN CONSUMPTION Enzyme Preparations and Microorganisms § 173.130 Carbohydrase derived from Rhizopus oryzae. Carbohydrase from Rhizopus...

  1. 21 CFR 173.130 - Carbohydrase derived from Rhizopus oryzae.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SECONDARY DIRECT FOOD ADDITIVES PERMITTED IN FOOD FOR HUMAN CONSUMPTION Enzyme Preparations and Microorganisms § 173.130 Carbohydrase derived from Rhizopus oryzae. Carbohydrase from Rhizopus...

  2. 21 CFR 173.130 - Carbohydrase derived from Rhizopus oryzae.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) SECONDARY DIRECT FOOD ADDITIVES PERMITTED IN FOOD FOR HUMAN CONSUMPTION Enzyme Preparations and Microorganisms § 173.130 Carbohydrase derived from Rhizopus oryzae. Carbohydrase from Rhizopus...

  3. Genipin-crosslinked catechol-chitosan mucoadhesive hydrogels for buccal drug delivery.

    PubMed

    Xu, Jinke; Strandman, Satu; Zhu, Julian X X; Barralet, Jake; Cerruti, Marta

    2015-01-01

    Drug administration via buccal mucosa is an attractive drug delivery strategy due to good patient compliance, prolonged localized drug effect, and avoidance of gastrointestinal drug metabolism and first-pass elimination. Buccal drug delivery systems need to maintain an intimate contact with the mucosa lining in the wet conditions of the oral cavity for long enough to allow drug release and absorption. For decades, mucoadhesive polymers such as chitosan (CS) and its derivatives have been explored to achieve this. In this study, inspired by the excellent wet adhesion of marine mussel adhesive protein, we developed a buccal drug delivery system using a novel catechol-functionalized CS (Cat-CS) hydrogel. We covalently bonded catechol functional groups to the backbone of CS, and crosslinked the polymer with a non-toxic crosslinker genipin (GP). We achieved two degrees of catechol conjugation (9% and 19%), forming Cat9-CS/GP and Cat19-CS/GP hydrogels, respectively. We confirmed covalent bond formation during the catechol functionalization and GP crosslinking during the gel formation. The gelation time and the mechanical properties of Cat-CS hydrogels are similar to those of CS only hydrogels. Catechol groups significantly enhanced mucoadhesion in vitro (7 out of the 10 Cat19-CS hydrogels were still in contact with porcine mucosal membrane after 6 h, whereas all of the CS hydrogels lost contact after 1.5 h). The new hydrogel systems sustained the release of lidocaine for about 3 h. In-vivo, we compared buccal patches made of Cat19-CS/GP and CS/GP adhered to rabbit buccal mucosa. We were able to detect lidocaine in the rabbit's serum at concentration about 1 ng/ml only from the Cat19-CS patch, most likely due to the intimate contact provided by mucoadhesive Cat19-CS/GP systems. No inflammation was observed on the buccal tissue in contact with any of the patches tested. These results show that the proposed catechol-modified CS hydrogel is a promising mucoadhesive and biocompatible hydrogel system for buccal drug delivery. PMID:25453967

  4. Solid–liquid equilibria of closely boiling compounds of 4-methoxyphenol and catechol with p-cresol

    Microsoft Academic Search

    Ho-mu Lin; Yu-Hsing Chou; Fu-Li Wu; Ming-Jer Lee

    2004-01-01

    Solid–liquid equilibrium data were measured for binary and ternary mixtures composed of p-cresol with closely boiling compounds: 4-methoxyphenol and catechol. Experimental results revealed that all the binaries behave as simple eutectic systems. The eutectic loci were also observed for the mixtures of 4-methoxyphenol+catechol+p-cresol, from which a ternary solid–liquid equilibrium phase diagram was obtained. The Wilson and the NRTL models were

  5. Electrooxidation of catechols in the presence of benzenesulfinic acid. Application to electro-organic synthesis of new sulfone derivatives

    Microsoft Academic Search

    D Nematollahi; R. A Rahchamani

    2002-01-01

    The mechanism of electrochemical oxidation of catechol (1a), 3-methylcatechol (1b) and 3-methoxycatechol (1c) in the presence of benzenesulfinic acid (3) as a nucleophile has been studied in an aqueous solution using cyclic voltammetry and controlled-potential coulometry. The results indicate that the catechol derivatives (1a–1c) are converted to sulfone derivatives (4a–4c) through Michael addition of benzenesulfinate to anodically generated o-quinones (2a–2c).

  6. Genetic characterization of red rice (Oryza sativa L.) and control in imidazolinone tolerant rice (Oryza sativa L.) 

    E-print Network

    Ottis, Brian Vance

    2002-01-01

    Red rice from the southern United States was collected and analyzed using Simple Sequence Length Polymorphism (SSLP) markers in an effort to test the assumption that red rice is Oryza sativa ssp. indica. The 18 markers used are distributed across...

  7. Genetic characterization of red rice (Oryza sativa L.) and control in imidazolinone tolerant rice (Oryza sativa L.)

    E-print Network

    Ottis, Brian Vance

    2002-01-01

    Red rice from the southern United States was collected and analyzed using Simple Sequence Length Polymorphism (SSLP) markers in an effort to test the assumption that red rice is Oryza sativa ssp. indica. The 18 markers used are distributed across...

  8. Improving Pharmaceutical Protein Production in Oryza sativa

    PubMed Central

    Kuo, Yu-Chieh; Tan, Chia-Chun; Ku, Jung-Ting; Hsu, Wei-Cho; Su, Sung-Chieh; Lu, Chung-An; Huang, Li-Fen

    2013-01-01

    Application of plant expression systems in the production of recombinant proteins has several advantages, such as low maintenance cost, absence of human pathogens, and possession of complex post-translational glycosylation capabilities. Plants have been successfully used to produce recombinant cytokines, vaccines, antibodies, and other proteins, and rice (Oryza sativa) is a potential plant used as recombinant protein expression system. After successful transformation, transgenic rice cells can be either regenerated into whole plants or grown as cell cultures that can be upscaled into bioreactors. This review summarizes recent advances in the production of different recombinant protein produced in rice and describes their production methods as well as methods to improve protein yield and quality. Glycosylation and its impact in plant development and protein production are discussed, and several methods of improving yield and quality that have not been incorporated in rice expression systems are also proposed. Finally, different bioreactor options are explored and their advantages are analyzed. PMID:23615467

  9. Structural Insights into Sulfite Oxidase Deficiency

    SciTech Connect

    Karakas,E.; Wilson, H.; Graf, T.; Xiang, S.; Jaramillo-Busquets, S.; Rajagopalan, K.; Kisker, C.

    2005-01-01

    Sulfite oxidase deficiency is a lethal genetic disease that results from defects either in the genes encoding proteins involved in molybdenum cofactor biosynthesis or in the sulfite oxidase gene itself. Several point mutations in the sulfite oxidase gene have been identified from patients suffering from this disease worldwide. Although detailed biochemical analyses have been carried out on these mutations, no structural data could be obtained because of problems in crystallizing recombinant human and rat sulfite oxidases and the failure to clone the chicken sulfite oxidase gene. We synthesized the gene for chicken sulfite oxidase de novo, working backward from the amino acid sequence of the native chicken liver enzyme by PCR amplification of a series of 72 overlapping primers. The recombinant protein displayed the characteristic absorption spectrum of sulfite oxidase and exhibited steady state and rapid kinetic parameters comparable with those of the tissue-derived enzyme. We solved the crystal structures of the wild type and the sulfite oxidase deficiency-causing R138Q (R160Q in humans) variant of recombinant chicken sulfite oxidase in the resting and sulfate-bound forms. Significant alterations in the substrate-binding pocket were detected in the structure of the mutant, and a comparison between the wild type and mutant protein revealed that the active site residue Arg-450 adopts different conformations in the presence and absence of bound sulfate. The size of the binding pocket is thereby considerably reduced, and its position relative to the cofactor is shifted, causing an increase in the distance of the sulfur atom of the bound sulfate to the molybdenum.

  10. NADPH Oxidases and Angiotensin II Receptor Signaling

    PubMed Central

    Garrido, Abel Martin; Griendling, Kathy K.

    2010-01-01

    Over the last decade many studies have demonstrated the importance of reactive oxygen species (ROS) production by NADPH oxidases in angiotensin II (Ang II) signaling, as well as a role for ROS in the development of different diseases in which Ang II is a central component. In this review, we summarize the mechanism of activation of NADPH oxidases by Ang II and describe the molecular targets of ROS in Ang II signaling in the vasculature, kidney and brain. We also discuss the effects of genetic manipulation of NADPH oxidase function on the physiology and pathophysiology of the renin angiotensin system. PMID:19059306

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

    NASA Astrophysics Data System (ADS)

    Jankovi?, Ivana A.; Šaponji?, Zoran V.; Džunuzovi?, Enis S.; Nedeljkovi?, Jovan M.

    2010-01-01

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

  12. Structure-based drug design of catechol-O-methyltransferase inhibitors for CNS disorders.

    PubMed

    Ma, Zhiguo; Liu, Hongming; Wu, Baojian

    2014-03-01

    Catechol-O-methyltransferase (COMT) is of great importance in pharmacology because it catalyzes the metabolism (methylation) of endogenous and xenobiotic catechols. Moreover, inhibition of COMT is the drug target in the management of central nervous system (CNS) disorders such as Parkinson's disease due to its role in regulation of the dopamine level in the brain. The X-ray crystal structures for COMT have been available since 1994. The active sites for cofactor and substrate/inhibitor binding are well resolved to an atomic level, providing valuable insights into the catalytic mechanisms as well as the role of magnesium ions in catalysis. Determination of how the substrates/inhibitors bind to the protein leads to a structure-based approach that has resulted in potent and selective inhibitors. This review focuses on the design of two types of inhibitors (nitrocatechol-type and bisubstrate inhibitors) for COMT using the protein structures. PMID:23713800

  13. Brucella abortus strain 2308 produces brucebactin, a highly efficient catecholic siderophore

    Microsoft Academic Search

    Manuel I. Gonza; J. Sangari; Juan M. Garci

    Brucella abortus is known to produce 2,3-dihydroxybenzoate (2,3-DHBA) and to use this catechol as a siderophore to grow under iron-limited conditions. In this study a mutant (BAM41) is described that is deficient in siderophore production by insertion of Tn5 in the virulent B. abortus strain 2308. This mutant was unable to grow on iron-deprived medium and its growth could not

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

    Microsoft Academic Search

    Alex Avdeef; Stephen R. Sofen; Thomas L. Bregante; Kenneth N. Raymond

    1978-01-01

    The stability constants of ferric complexes with several substituted catechol (1,2-dihydroxybenzene) ligands in aqueous solutions of low ionic strength have been determined at 27°C in the pH range 2 to 11. Enterobactin, the principal siderophore of enteric bacteria, is a tricatechol and, from the formation constants reported here, is estimated to have a formation constant with ferric ion which is

  15. Catechol O-methyltransferase pharmacogenomics and selective serotonin reuptake inhibitor response

    Microsoft Academic Search

    Y Ji; J Biernacka; K Snyder; M Drews; L L Pelleymounter; C Colby; L Wang; D A Mrazek; R M Weinshilboum

    2012-01-01

    We applied a systematic pharmacogenetic approach to investigate the role of genetic variation in the gene encoding catechol O-methyltransferase (COMT) in individual variation in selective serotonin reuptake inhibitor (SSRI) response among depressed patients. In all, 23 single-nucleotide polymorphisms (SNPs) in COMT were genotyped using DNA from the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study (N=1914). One SNP, rs13306278, located

  16. Role of catechol structure in the adsorption and transformation reactions of L-DOPA in soils.

    PubMed

    Furubayashi, Akihiro; Hiradate, Syuntaro; Fujii, Yoshiharu

    2007-02-01

    3-(3',4'-Dihydroxyphenyl)-L-alanine (L-DOPA), which is synthesized in velvet bean (Mucuna pruriens), inhibits plant growth. The concentration of L-DOPA in soil is reduced by adsorption and transformation reactions, which can result in the reduction of its plant-growth-inhibitory activity. To determine which part of the L-DOPA structure is involved in the adsorption and soil transformation reactions, we compared the kinetics of L-DOPA disappearance in a volcanic ash soil with that of L-phenylalanine (3-phenyl-L-alanine) and L-tyrosine (3-(4'-hydroxyphenyl)-L-alanine), compounds that are similar in structure to L-DOPA but do not have a catechol (o-dihydroxybenzene) moiety. L-Phenylalanine and L-tyrosine were not adsorbed and transformed in the soil at equilibrium pH values between 4 and 7. These results suggest that the adsorption and transformation reactions of L-DOPA in the soil involve the catechol moiety and not the amino and carboxylic acid groups, which are common to all three compounds. Like L-DOPA, (+)-catechin, another allelochemical that contains a catechol moiety, underwent adsorption and soil transformation reactions. Thus, we concluded that the concentrations of allelochemicals bearing a catechol moiety in soils will decrease rapidly owing to adsorption and transformation reactions, and this decrease will be faster in soils with a high pH value or high adsorption ability. Owing to this decrease in concentration, allelopathic phenomena may not occur. PMID:17195117

  17. Catechol 1,2-dioxygenase from Acinetobacter calcoaceticus: purification and properties.

    PubMed Central

    Patel, R N; Hou, C T; Felix, A; Lillard, M O

    1976-01-01

    Procedures for the purification of catechol 1,2-dioxygenase from extracts of Acinetobacter calcoaceticus strain ADP-96 are described. The purified enzyme was homogeneous as judged by ultracentrifugation and acrylamide gel electrophoresis. The enzyme contained 2 g-atoms of iron per mol of protein. The enzyme had a broad substrate specificity and catalyzed the oxidation of catechol, 4-methylcatechol, 3-methylcatechol, and 3-isopropyl catechol. The activity of the enzyme was inhibited by heavy metals, sulfhydryl inhibitors, and substrate analogues. The molecular weight of the enzyme was 85,000 as estimated by filtration on Bio-Gel agarose and 81,000 as estimated by sedimentation equilibrium analysis. The subunit size determined by sodium dodecyl sulfate-gel electrophoresis was 40,000. The amino terminal amino acid was methionine. The amino acid composition and spectral properties of 1,2-dioxygenase are also presented. Antisera prepared against the purified enzyme cross-reacted and inhibited enzyme activity in crude extracts from the other strain of A. calcoaceticus, but failed to cross-react and inhibit isofunctional enzyme from organisms of the genera Pseudomonas, Alcaligenes, and Nocardia. Images PMID:58860

  18. A catechol biosensor based on a gold nanoparticles encapsulated-dendrimer.

    PubMed

    Singh, Ravindra P

    2011-03-21

    Tyrosinase has been immobilized on a Au nanoparticles encapsulated-dendrimer bonded conducting polymer on a glassy carbon electrode for the estimation of catechol. The modified electrode was characterized by cyclic voltammetry and AFM techniques. The principle of catechol estimation was based on the reduction of biocatalytically liberated quinone species at +0.2 V versus Ag/AgCl (3 M KCl), with good stability, sensitivity, and featuring a low detection limit (about 0.002 ?M) and wide linear range (0.005 ?M-120 ?M). The electrochemical redox peak of catechol on the GCE/PolyPATT/Den(AuNPs)/tyrosinase was also investigated. A response time of 7 s, reusability up to 5 cycles and a shelf life of more than 2 months under refrigerated conditions were reported. Various parameters influencing biosensor performance have been optimized including pH, temperature, and applied potential. The utility and application of this nanobiosensor was tested in a real water samples. PMID:21240422

  19. Phenol and catechol biodegradation by the haloalkaliphile Halomonas campisalis: influence of pH and salinity.

    PubMed

    Alva, Victor A; Peyton, Brent M

    2003-10-01

    Removal of aromatic compounds from alkaline and/or saline industrial wastewater is an environmental concern for industry. In addition, aromatics may be accumulating in soda lakes, unique natural systems, where the fate and toxicity of these contaminants is unknown. To determine the feasibility of aromatic compound biodegradation in saline and alkaline conditions, the effect of pH and salinity on the biodegradation of phenol as a model aromatic waste compound by the haloalkaliphilic bacterium Halomonas campisalis was examined. Phenol was degraded as a source of carbon and energy at pH 8-11 and 0-150 g/L NaCl. Metabolic intermediates catechol, cis,cis-muconate, and (+)-muconolactone were identified, thus indicating that phenol was degraded via the beta-ketoadipate metabolic pathway. Although phenol and catechol were completely degraded in all cases, small amounts of cis,cis-muconate accumulated proportionally to increases in pH. There was no noticeable influence of salinity on cis,cis-muconate accumulation except at 0 g/L NaCl where it was completely degraded. These results indicate that it may be feasible to use haloalkaliphiles forthe treatment of aromatics present in saline and/or alkaline systems. This is the first report of phenol and catechol biodegradation under combined saline and alkaline conditions. PMID:14572091

  20. Chromosomal polymorphism of ribosomal genes in the genus Oryza

    PubMed Central

    Lee, Yung-I; Cheng, Yueh-Yun; Chou, Yi-Jia; Lu, Chia-Fu

    2008-01-01

    The genes encoding for 18S–5.8S–28S ribosomal RNA (rDNA) are both conserved and diversified. We used rDNA as probe in the fluorescent in situ hybridization (rDNA-FISH) to localized rDNAs on chromosomes of 15 accessions representing ten Oryza species. These included cultivated and wild species of rice, and four of them are tetraploids. Our results reveal polymorphism in the number of rDNA loci, in the number of rDNA repeats, and in their chromosomal positions among Oryza species. The numbers of rDNA loci varies from one to eight among Oryza species. The rDNA locus located at the end of the short arm of chromosome 9 is conserved among the genus Oryza. The rDNA locus at the end of the short arm of chromosome 10 was lost in some of the accessions. In this study, we report two genome specific rDNA loci in the genus Oryza. One is specific to the BB genome, which was localized at the end of the short arm of chromosome 4. Another may be specific to the CC genome, which was localized in the proximal region of the short arm of chromosome 5. A particular rDNA locus was detected as stretched chromatin with bright signals at the proximal region of the short arm of chromosome 4 in O.grandiglumis by rDNA-FISH. We suggest that chromosomal inversion and the amplification and transposition of rDNA might occur during Oryza species evolution. The possible mechanisms of cyto-evolution in tetraploid Oryza species are discussed. PMID:18214422

  1. Activation of polyphenol oxidase of chloroplasts.

    PubMed

    Tolbert, N E

    1973-02-01

    Polyphenol oxidase of leaves is located mainly in chloroplasts isolated by differential or sucrose density gradient centrifugation. This activity is part of the lamellar structure that is not lost on repeated washing of the plastids. The oxidase activity was stable during prolonged storage of the particles at 4 C or -18 C. The Km (dihydroxyphenylalanine) for spinach leaf polyphenol oxidase was 7 mm by a spectrophotometric assay and 2 mm by the manometric assay. Polyphenol oxidase activity in the leaf peroxisomal fraction, after isopycnic centrifugation on a linear sucrose gradient, did not coincide with the peroxisomal enzymes but was attributed to proplastids at nearly the same specific density.Plants were grouped by the latency properties for polyphenol oxidase in their isolated chloroplasts. In a group including spinach, Swiss chard, and beet leaves the plastids immediately after preparation from fresh leaves required a small amount of light for maximal rates of oxidation of dihydroxyphenylalanine. Polyphenol oxidase activity in the dark or light increased many fold during aging of these chloroplasts for 1 to 5 days. Soluble polyphenol oxidase of the cytoplasm was not so stimulated. Chloroplasts prepared from stored leaves were also much more active than from fresh leaves. Maximum rates of dihydroxyphenylalanine oxidation were 2 to 6 mmoles x mg(-1) chlorophyll x hr(-1). Equal stimulation of latent polyphenol oxidase in fresh or aged chloroplasts in this group was obtained by either light, an aged trypsin digest, 3-(4-chlorophenyl)-1, 1-dimethylurea, or antimycin A. A variety of other treatments did not activate or had little effect on the oxidase, including various peptides, salts, detergents, and other proteolytic enzymes.Activation of latent polyphenol oxidase in spinach chloroplasts by trypsin amounted to as much as 30-fold. The trypsin activation occurred even after the trypsin had been treated with 10% trichloroacetic acid, 1.0 n HCl or boiled for 30 minutes. No single peptide from the digested trypsin was found to be the sole activating factor. About 0.25 mug of trypsin activated 50% the polyphenol oxidase activity in a standard chloroplast assay containing 2.1 mug of chlorophyll. Treatment of spinach chloroplasts with tris buffer or ethylenediamine tetraacetate extracted the ATPase activity, but the polyphenol oxidase activity remained with the broken plastids. However these treatments increased the latent polyphenol oxidase activity 50- to 100-fold.Chloroplasts from a second group of plants, including alfalfa, wheat, oats, peas, and sugarcane leaves, oxidized dihydroxyphenylalanine at a rate of 11 to 120 mumoles x mg(-1) chlorophyll x hr(-1). Polyphenol oxidase in these chloroplasts required a low intensity of red light for activity. Fifty or 75% activation of the oxidase in wheat chloroplasts required 4 to 6 foot candles of light and more light was required for alfalfa chloroplasts. Blue or far red light were ineffective. Trypsin was inhibitory. Upon aging chloroplasts from wheat leaves, but not alfalfa or peas, for 5 to 7 days at 4 C the total polyphenol oxidase activity did not increase, but the activation characteristics changed to those of chloroplasts from the spinach group. Chloroplasts from a third group of plants, including bean, tomato, and corn leaves, slowly oxidized dihydroxyphenylalanine in the dark and exhibited no latency. PMID:16658308

  2. Identification and QTL mapping of blast resistance in wild Oryza species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leaf blast disease of rice (Oryza sativa L.) caused by Magnaporthe oryzae B. Couch is one of the most devastating rice fungal diseases worldwide. Wild relatives of rice (Oryza spp.) may contain novel genes for biotic and abiotic stress resistance lost during domestication. A collection of 67 wild ...

  3. Evolutionary relationships in the Sativa group of Oryza based on isozyme data

    E-print Network

    Paris-Sud XI, Université de

    Evolutionary relationships in the Sativa group of Oryza based on isozyme data Gérard SECOND O Montpellier Cedex Summary The wild and weedy species of the Sativa group of Oryza were studied entre lignées du groupe Sativa (génôme AA) d'Oryza L. étudiées à 24 locus d'isozymes Les espèces

  4. Evaluation of antioxidant, lipid, and protein fractions of accessions of Oryza Species.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The genus Oryza has given rise to rice (Oryza sativa L.), a major source of food for much of the human population. The Oryza genus is small, including only 23 species, but it is remarkably diverse in terms of its ecological adaptation. This diversity may not only be restricted to ecological characte...

  5. Targeting NADPH oxidases in vascular pharmacology

    PubMed Central

    Schramm, Agata; Matusik, Pawe?; Osmenda, Grzegorz; Guzik, Tomasz J

    2012-01-01

    Oxidative stress is a molecular dysregulation in reactive oxygen species (ROS) metabolism, which plays a key role in the pathogenesis of atherosclerosis, vascular inflammation and endothelial dysfunction. It is characterized by a loss of nitric oxide (NO) bioavailability. Large clinical trials such as HOPE and HPS have not shown a clinical benefit of antioxidant vitamin C or vitamin E treatment, putting into question the role of oxidative stress in cardiovascular disease. A change in the understanding of the molecular nature of oxidative stress has been driven by the results of these trials. Oxidative stress is no longer perceived as a simple imbalance between the production and scavenging of ROS, but as a dysfunction of enzymes involved in ROS production. NADPH oxidases are at the center of these events, underlying the dysfunction of other oxidases including eNOS uncoupling, xanthine oxidase and mitochondrial dysfunction. Thus NADPH oxidases are important therapeutic targets. Indeed, HMG-CoA reductase inhibitors (statins) as well as drugs interfering with the renin-angiotensin-aldosterone system inhibit NADPH oxidase activation and expression. Angiotensin-converting enzyme (ACE) inhibitors, AT1 receptor antagonists (sartans) and aliskiren, as well as spironolactone or eplerenone, have been discussed. Molecular aspects of NADPH oxidase regulation must be considered, while thinking about novel pharmacological targeting of this family of enzymes consisting of several homologs Nox1, Nox2, Nox3, Nox4 and Nox5 in humans. In order to properly design trials of antioxidant therapies, we must develop reliable techniques for the assessment of local and systemic oxidative stress. Classical antioxidants could be combined with novel oxidase inhibitors. In this review, we discuss NADPH oxidase inhibitors such as VAS2870, VAS3947, GK-136901, S17834 or plumbagin. Therefore, our efforts must focus on generating small molecular weight inhibitors of NADPH oxidases, allowing the selective inhibition of dysfunctional NADPH oxidase homologs. This appears to be the most reasonable approach, potentially much more efficient than non-selective scavenging of all ROS by the administration of antioxidants. PMID:22405985

  6. Purification and partial biochemical characterization of polyphenol oxidase from mango (Mangifera indica cv. Manila).

    PubMed

    Palma-Orozco, Gisela; Marrufo-Hernández, Norma A; Sampedro, José G; Nájera, Hugo

    2014-10-01

    Polyphenol oxidase (PPO) is an enzyme widely distributed in the plant kingdom that has been detected in most fruits and vegetables. PPO was extracted and purified from Manila mango (Mangifera indica), and its biochemical properties were studied. PPO was purified 216-fold by hydrophobic interaction and ion exchange chromatography. PPO was purified to homogeneity, and the estimated PPO molecular weight (MW) by SDS-PAGE was ?31.5 kDa. However, a MW of 65 kDa was determined by gel filtration, indicating a dimeric structure for the native PPO. The isolated PPO showed the highest affinity to pyrogallol (Km = 2.77 mM) followed by 4-methylcatechol (Km = 3.14 mM) and catechol (Km = 15.14 mM). The optimum pH for activity was 6.0. PPO was stable in the temperature range of 20-70 °C. PPO activity was completely inhibited by tropolone, ascorbic acid, sodium metabisulfite, and kojic acid at 0.1 mM. PMID:25211397

  7. Characterization of germin-like protein with polyphenol oxidase activity from Satsuma mandarine.

    PubMed

    Cheng, Xi; Huang, Xingjian; Liu, Siyu; Tang, Mi; Hu, Wanfeng; Pan, Siyi

    2014-07-01

    Polyphenol oxidases (PPOs) catalyzing the oxygen dependent oxidation of phenols to quinones are ubiquitously distributed in plants and are assumed to be involved in plant defense against pests and pathogens. A protein with high PPO activity was identified in Satsuma mandarine, extracted with Tris-HCl buffer, purified by salt precipitation and column chromatography, and characterized by mass spectrometry as germin-like protein (GLP), which belongs to pathogenesis related protein (PR) family. In the present study, the structure and enzymatic properties of GLP were characterized using spectroscopy methods. Based on native PAGE analysis, the molecular weight of GLP was estimated to be 108 kDa and GLP was identified as a pentamer containing five subunits of 22 kDa. The optimum pH and temperature for PPO catalyzing activity of GLP was 6.5 and 65°C, respectively. Kinetic constants were 0.0365 M and 0.0196 M with the substrates catechol and pyrogallol, respectively. The structural characterization of GLP provided better insights into the regions responsible for its PPO activity. PMID:24845377

  8. Characteristics of murine protoporphyrinogen oxidase.

    PubMed Central

    Proulx, K. L.; Dailey, H. A.

    1992-01-01

    Protoporphyrinogen oxidase (EC 1.3.3.4) (PPO) is the penultimate enzyme of the heme biosynthetic pathway. Mouse PPO has been purified in low yield and kinetically characterized by this laboratory previously. A new more rapid purification procedure is described herein, and with this protein we detect a noncovalently bound flavin moiety. This flavin is present at approximately stoichiometric amounts in the purified enzyme and has been identified by its fluorescence spectrum and high performance liquid chromatography as flavin mononucleotide (FMN). Fluorescence quenching studies on the flavin yielded a Stern-Volmer quenching constant of 12.08 M-1 for iodide and 1.1 M-1 for acrylamide. Quenching of enzyme tryptophan fluorescence resulted in quenching constants of 6 M-1 and 10 M-1 for iodide and acrylamide, respectively. Plasma scans performed on purified enzyme preparations did not reveal the presence of stoichiometric amounts of protein-bound metal ions, and we were unable to detect any protein-associated pyrroloquinoline quinone (PQQ). Data from circular dichroism studies predict a secondary structure of the native protein consisting of 30.5% alpha helix, 40.5% beta sheet, 13.7% turn, and 15.3% random coil. Denaturation of PPO with urea resulted in a biphasic curve when ellipticity is plotted against urea concentration, typical of amphipathic proteins. PMID:1304921

  9. Azide inhibition of urate oxidase.

    PubMed

    Gabison, Laure; Colloc'h, Nathalie; Prangé, Thierry

    2014-07-01

    The inhibition of urate oxidase (UOX) by azide was investigated by X-ray diffraction techniques and compared with cyanide inhibition. Two well characterized sites for reagents are present in the enzyme: the dioxygen site and the substrate-binding site. To examine the selectivity of these sites towards azide inhibition, several crystallization conditions were developed. UOX was co-crystallized with azide (N3) in the presence or absence of either uric acid (UA, the natural substrate) or 8-azaxanthine (8AZA, a competitive inhibitor). In a second set of experiments, previously grown orthorhombic crystals of the UOX-UA or UOX-8AZA complexes were soaked in sodium azide solutions. In a third set of experiments, orthorhombic crystals of UOX with the exchangeable ligand 8-nitroxanthine (8NXN) were soaked in a solution containing uric acid and azide simultaneously (competitive soaking). In all assays, the soaking periods were either short (a few hours) or long (one or two months). These different experimental conditions showed that one or other of the sites, or the two sites together, could be inhibited. This also demonstrated that azide not only competes with dioxygen as cyanide does but also competes with the substrate for its enzymatic site. A model in agreement with experimental data would be an azide in equilibrium between two sites, kinetically in favour of the dioxygen site and thermodynamically in favour of the substrate-binding site. PMID:25005084

  10. Biosynthesis of silver nanoparticles by phytopathogen Xanthomonas oryzae pv. oryzae strain BXO8.

    PubMed

    Narayanan, Kannan Badri; Sakthivel, Natarajan

    2013-09-28

    Extracellular biogenic synthesis of silver nanoparticles with various shapes using the rice bacterial blight bacterium Xanthomonas oryzae pv. oryzae BXO8 is reported. The synthesized silver nanoparticles were characterized by UV-Vis spectroscopy, powder X-ray diffractometry (XRD), scanning electron microscopy, energy dispersive X-ray spectrometry, and highresolution transmission electron microscopy (HR-TEM). Based on the evidence of HR-TEM, the synthesized particles were found to be spherical, with anisotropic structures such as triangles and rods, with an average size of 14.86 nm. The crystalline nature of silver nanoparticles was evident from the bright circular spots in the SAED pattern, clear lattice fringes in the high-resolution TEM images, and peaks in the XRD pattern. The FTIR spectrum showed that biomolecules containing amide and carboxylate groups are involved in the reduction and stabilization of the silver nanoparticles. Using such a biological method for the synthesis of silver nanoparticles is a simple, viable, cost-effective, and environmentally friendly process, which can be used in antimicrobial therapy. PMID:23751558

  11. gltB/D mutants of Xanthomonas oryzae pv. oryzae are virulence deficient.

    PubMed

    Pandey, Alok; Ray, Suvendra Kumar; Sonti, Ramesh V; Rajeshwari, R

    2014-01-01

    Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial blight, a serious disease of rice. Upon clip inoculation of rice leaves, Xoo causes typical V-shaped lesions whose leading edge moves through the mid-veinal region. We have isolated a virulence deficient mutant of Xoo, referred to as BXO808 that causes limited lesions which primarily extend through the side-veinal regions of rice leaves. Functional complementation studies identified a clone, pSR19, from a cosmid genomic library that restored wild-type virulence and lesion phenotype to BXO808. Transposon mutagenesis of the pSR19 clone, marker exchange experiments, and targeted mutagenesis, revealed that the BXO808 phenotype is due to mutation in the gltB/D genes of Xoo, which encode glutamate synthase subunits ? and ?, respectively. The gltB/D mutants that were generated in this study also exhibited virulence deficiency, an altered lesion phenotype and growth deficiency on minimal medium with low levels of ammonium as a sole nitrogen source. This is the first report that mutations in the gltB/D genes of Xoo cause virulence deficiency. PMID:23995777

  12. Production of biologically active recombinant human lactoferrin in Aspergillus oryzae.

    PubMed

    Ward, P P; Lo, J Y; Duke, M; May, G S; Headon, D R; Conneely, O M

    1992-07-01

    We report the production of recombinant human lactoferrin in Aspergillus oryzae. Expression of human lactoferrin (hLF), a 78 kD glycoprotein, was achieved by placing the cDNA under the control of the A. oryzae alpha-amylase promoter and the 3' flanking region of the A. niger glucoamylase gene. Using this system, hLF is expressed and secreted into the growth medium at levels up to 25 mg/l. The recombinant lactoferrin is indistinguishable from human milk lactoferrin with respect to its size, immunoreactivity, and iron-binding capacity. The recombinant protein appears to be appropriately N-linked glycosylated and correctly processed at the N-terminus by the A. oryzae secretory apparatus. Lactoferrin is the largest heterologous protein and the first mammalian glycoprotein expressed in the Aspergillus system to date. Hence, this expression system appears suitable for the large-scale production and secretion of biologically active mammalian glycoproteins. PMID:1368268

  13. Catechol, a bioactive degradation product of salicortin, reduces TNF-? induced ICAM-1 expression in human endothelial cells.

    PubMed

    Knuth, Susanne; Schübel, Helmut; Hellemann, Martin; Jürgenliemk, Guido

    2011-07-01

    The phenolic glucoside salicortin was isolated from a Willow bark extract, and its ability to reduce the TNF- ? induced ICAM-1 expression (10 ng/mL, 30 min pretreatment with salicortin) was tested IN VITRO on human microvascular endothelial cells (HMEC-1). After 24 h, 25 µM salicortin decreased the TNF- ? induced ICAM-1 expression to 65.9 % compared to cells which were treated only with TNF- ?. In parallel, the stability of 25 µM salicortin under assay conditions was determined by HPLC. Within 24 h, the salicortin concentration decreased to 3.1 µM whereas catechol, a known NF- ?B inhibitor, rose as a metabolite. After 8 h the catechol concentration was relatively constant and varied between 8.2 and 10.9 µM. Considering this degradation in the IN VITRO test system, 10 µM catechol was added 8 h after TNF- ? stimulation, and 16 h later the ICAM-1 expression was determined. In this setting, the ICAM-1 expression was reduced to 74.8 %. This is comparable to the effect obtained from 25 µM salicortin and indicates that its activity is related to the generation of catechol, as salicin, saligenin, and salicylic acid are only marginally active or inactive in this test system in a concentration up to 50 µM. These results indicate catechol as an important bioactive metabolite from salicortin. PMID:21305449

  14. Heterokaryosis and the parasexual cycle in Pyricularia oryzae Cav 

    E-print Network

    Genovesi, Anthony Dennis

    1975-01-01

    oryzae Cav. 1s the causal agent of rice blast, the most destructive d1sease of rice. Plant breeders have obtained resistant var1eties of the rice plant, but due to the highly variable pathogenic character of P. orgzao such resistance is usually circum...- vented 1n a few years. Several mechan1sms have been suggested as the possible basis for such variability, but heterokaryosis and the parasexual cycle seem the most likely. Growth rate and sporulat1on data of P. oryzae were obtai ned for various...

  15. Cyclopiazonic Acid Biosynthesis of Aspergillus flavus and Aspergillus oryzae

    PubMed Central

    Chang, Perng-Kuang; Ehrlich, Kenneth C.; Fujii, Isao

    2009-01-01

    Cyclopiazonic acid (CPA) is an indole-tetramic acid neurotoxin produced by some of the same strains of A. flavus that produce aflatoxins and by some Aspergillus oryzae strains. Despite its discovery 40 years ago, few reviews of its toxicity and biosynthesis have been reported. This review examines what is currently known about the toxicity of CPA to animals and humans, both by itself or in combination with other mycotoxins. The review also discusses CPA biosynthesis and the genetic diversity of CPA production in A. flavus/oryzae populations. PMID:22069533

  16. The biosynthesis, structure and gelatinization properties of starches from wild and cultivated African rice species (Oryza barthii and Oryza glaberrima).

    PubMed

    Wang, Kai; Wambugu, Peterson W; Zhang, Bin; Wu, Alex Chi; Henry, Robert J; Gilbert, Robert G

    2015-09-20

    The molecular structure and gelatinization properties of starches from domesticated African rice (Oryza glaberrima) and its wild progenitor (Oryza barthii) are determined and comparison made with Asian domesticated rice (Oryza sativa), the commonest commercial rice. This suggests possible enzymatic processes contributing to the unique traits of the African varieties. These have similar starch structures, including smaller amylose molecules, but larger amounts of amylose chains across the whole amylose chain-length distribution, and higher amylose contents, than O. sativa. They also show a higher proportion of two- and three-lamellae spanning amylopectin branch chains (degree of polymerization 34-100) than O. sativa, which contributes to their higher gelatinization temperatures. Fitting amylopectin chain-length distribution with a biosynthesis-based mathematical model suggests that the reason for this difference might be because O. glaberrima and O. barthii have more active SSIIIa and/or less active SBEIIb enzymes. PMID:26050893

  17. The Bordetella Bfe System: Growth and Transcriptional Response to Siderophores, Catechols, and Neuroendocrine Catecholamines

    PubMed Central

    Anderson, Mark T.; Armstrong, Sandra K.

    2006-01-01

    Ferric enterobactin utilization by Bordetella bronchiseptica and Bordetella pertussis requires the BfeA outer membrane receptor. Under iron-depleted growth conditions, transcription of bfeA is activated by the BfeR regulator by a mechanism requiring the siderophore enterobactin. In this study, enterobactin-inducible bfeA transcription was shown to be TonB independent. To determine whether other siderophores or nonsiderophore catechols could be utilized by the Bfe system, various compounds were tested for the abilities to promote the growth of iron-starved B. bronchiseptica and induce bfeA transcription. The BfeA receptor transported ferric salmochelin, corynebactin, and the synthetic siderophores TRENCAM and MECAM. Salmochelin and MECAM induced bfeA transcription in iron-starved Bordetella cells, but induction by corynebactin and TRENCAM was minimal. The neuroendocrine catecholamines epinephrine, norepinephrine, and dopamine exhibited a remarkable capacity to induce transcription of bfeA. Norepinephrine treatment of B. bronchiseptica resulted in BfeR-dependent bfeA transcription, elevated BfeA receptor production, and growth stimulation. Pyrocatechol, carbidopa, and isoproterenol were similarly strong inducers of bfeA transcription, whereas tyramine and 3,4-dihydroxymandelic acid demonstrated low inducing activity. The results indicate that the inducer structure requires a catechol group for function and that the ability to induce bfeA transcription does not necessarily correlate with the ability to stimulate bacterial growth. The expanded range of catechol siderophores transported by the BfeA receptor demonstrates the potential versatility of the Bordetella Bfe iron retrieval system. The finding that catecholamine neurotransmitters activate bfeA transcription and promote growth suggests that Bordetella cells can perceive and may benefit from neuroendocrine catecholamines on the respiratory epithelium. PMID:16885441

  18. Crystallization and preliminary crystallographic studies of CbsA, a secretory exoglucanase from Xanthomonas oryzae pv. oryzae

    PubMed Central

    Kumar, Sushil; Haque, Asfarul S.; Jha, Gopaljee; Sonti, Ramesh V.; Sankaranarayanan, Rajan

    2012-01-01

    The bacterial pathogen Xanthomonas oryzae pv. oryzae causes bacterial leaf blight, a serious disease of rice. The secreted exoglucanase CbsA is an important virulence factor of this pathogen. It belongs to the glycosyl hydrolase 6 family of proteins based on the carbohydrate-active enzyme (CAZY) classification. In this study, CbsA has been overexpressed, purified and crystallized. The crystal diffracted to a resolution of 1.86?Å and belonged to space group P212121. It contained one monomer per asymmetric unit, with a solvent content of 45.8%. PMID:23027745

  19. Torsional Motion of the Chromophore Catechol following the Absorption of Ultraviolet Light

    NASA Astrophysics Data System (ADS)

    Young, J. D.; Staniforth, M.; Paterson, M. J.; Stavros, V. G.

    2015-06-01

    The ability to probe energy flow in molecules, following the absorption of ultraviolet light, is crucial to unraveling photophysical phenomena. Here we excite a coherent superposition of vibrational states in the first excited electronic state (S1 ) in catechol, resulting in a vibrational wave packet. The observed quantum beats, assigned to superpositions of the low-frequency, and strongly mixed, O-H torsional mode ?2 , elegantly demonstrate how changes in geometry upon photoionization from the S1 state to the ground state of the cation (D0 ) enables one to probe energy flow at the very early stages of photoexcitation in this biological chromophore.

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

    PubMed

    Vrchlabský, M; Sommer, L

    1968-09-01

    Methods are given for the extraction of iron(III), molybdenum(VI), titanium(IV), niobium(V), vanadium(IV), uranium(VI) and tungsten(VI) as ternary complexes with catechol and a quaternary cation such as n-butyltriphenylphosphonium, n-propyltriphenylphosphonium, tetraphenylarsonium, cetylpyridinium, cetyltrimethylammonium and 2,3,5-triphenyltetrazolium, the solvent being chloroform. By use of masking agents and pH control, some of these elements can be separated from each other by this means. PMID:18960382

  1. Direct inhibition of tyrosine hydroxylase from PC12 cells by catechol derivatives

    Microsoft Academic Search

    G. Laschinski; B. Kittner; M. Bräutigam

    1986-01-01

    Several drugs with a catechol moiety were studied for their potency to inhibit tyrosine hydroxylase (TH) from PC-12 cells in vitro. When the natural compounds tested were compared, dopamine, norepinephrine and 2(3,4-dihydroxyphenyl)-ethanol (DOPET) were most effective (IC50 between 1.4 and 3.6 µM with 0.5 µM 6(R,S)-l-erythro-5,6,7,8-tetrahydrobiopterin as cofactor). 3,4-Dihydroxyphenylalanine (DOPA; IC50: 35 µM) and 3,4-dihydroxyphenylacetic acid (DOPAC; IC50: 180 µM

  2. Growth promotion of synthetic catecholate derivatives on Gram-negative bacteria

    Microsoft Academic Search

    Rolf Reissbrodt; Lothar Heinisch; Ute Möllmann; Wolfgang Rabsch; Hermann Ulbricht

    1993-01-01

    Derivatives of benzoic acid, glyoxylic acid benzhydrazone, oxanilic acid and N-dihydroxybenzylidene-2,4,6-trimethylaminobenzene were investigated as catecholic iron chelators under iron-depleted conditions. Some of the compounds showed strong positive reactions in the universal chemical siderophore assay (CAS): 3,4-dihydroxybenzoic acid, glyoxylic acid 2,3-dihydroxybenzhydrazone, N-3,4-dihydroxybenzylidene-2,4,6-trimethylaminobenzene. In particular these compounds also enabled removal of iron from iron-saturated transferrin. Using various siderophore indicator strains (enterobacteriacecae, Pseudomonas

  3. Bioactive steroids from Oryza sativa L.

    PubMed

    Macías, Francisco A; Chinchilla, Nuria; Varela, Rosa M; Molinillo, José M G

    2006-07-01

    Rice is one of the most interesting crops in the world from both the social and the economic point of views. The monoculture practices along with the heavy use of herbicides are characteristic of modern agriculture and are inducing the appearance of tolerant and/or herbicide resistant weed biotypes. This is the case the world's main weed of rice barnyardgrass (Echinochloa crus-galli). Alternative strategies for weed suppression consist of the use of chemicals from rice due to necessity of obtaining new herbicides with new modes of action that could prevent resistance phenomena. In order to carry out a study that guides to the isolation of the most active compounds from rice, different extracts were achieved, and their activities evaluated. So, all the plant material was divided into three parts: fresh plant, dried plant, and fresh plant from Pluviotron. The aerial part was separated from roots in all cases and extracted in water, in organic solvents as well as with the Pluviotron device. The activity of the 12 extracts obtained was evaluated using a generalist bioassay, wheat etiolated coleoptiles bioassay, and a phytotoxic bioassay on barnyardgrass as target species. The bioactive extracts were fractionated and 15 compounds were isolated and identified by spectroscopic methods. Eight of these compounds were isolated for the first time in Oryza sativa. The most phytotoxic compounds on E. crus-galli were ergosterol peroxide and 7-oxo-stigmasterol. In the case of ergosterol peroxide the activity was higher than the commercial herbicide Logran. This is the first report of potential allelopathic activity of steroids on weeds based on their phytotoxicity. PMID:16620896

  4. Catechol 1,2-dioxygenase from Pseudomonas putida in organic media--an electron paramagnetic resonance study.

    PubMed

    Sanakis, Y; Mamma, D; Christakopoulos, P; Stamatis, H

    2003-11-01

    The ability of an isolated isozyme of catechol 1,2-dioxygenase from Pseudomonas putida DSM 437 to function in a non-aqueous environment was investigated. The lyophilized enzyme is able to keep its catalytic function catalyzing the oxidation of catechol in n-hexane. Electron paramagnetic resonance (EPR) spectroscopy at liquid helium temperatures was applied to compare the properties of the non-heme iron of the enzyme in the organic solvent and in the aqueous solution. The catalytic performance of the enzyme in the organic solvent is correlated with the spectroscopic properties of the non-heme iron. PMID:14599591

  5. Experimental and Computational Evidence for the Mechanism of Intradiol Catechol Dioxygenation by Non-Heme Iron(III) Complexes

    PubMed Central

    Jastrzebski, Robin; Quesne, Matthew G; Weckhuysen, Bert M; de Visser, Sam P; Bruijnincx, Pieter C A

    2014-01-01

    Catechol intradiol dioxygenation is a unique reaction catalyzed by iron-dependent enzymes and non-heme iron(III) complexes. The mechanism by which these systems activate dioxygen in this important metabolic process remains controversial. Using a combination of kinetic measurements and computational modelling of multiple iron(III) catecholato complexes, we have elucidated the catechol cleavage mechanism and show that oxygen binds the iron center by partial dissociation of the substrate from the iron complex. The iron(III) superoxide complex that is formed subsequently attacks the carbon atom of the substrate by a rate-determining C=O bond formation step. PMID:25322920

  6. Pathotype and Genetic Diversity amongst Indian Isolates of Xanthomonas oryzae pv. oryzae

    PubMed Central

    Mishra, Deo; Vishnupriya, Manne Ramachander; Anil, Madhusoodana Girija; Konda, Kotilingam; Raj, Yog; Sonti, Ramesh V.

    2013-01-01

    A number of rice resistance genes, called Xa genes, have been identified that confer resistance against various strains of Xanthomonas oryzae pv. oryzae (Xoo), the causal agent of bacterial blight. An understanding of pathotype diversity within the target pathogen population is required for identifying the Xa genes that are to be deployed for development of resistant rice cultivars. Among 1024 isolates of Xoo collected from 20 different states of India, 11 major pathotypes were distinguished based on their reaction towards ten Xa genes (Xa1, Xa3, Xa4, xa5, Xa7, xa8, Xa10, Xa11, xa13, Xa21). Isolates belonging to pathotype III showing incompatible interaction towards xa8, xa13 and Xa21 and compatible interaction towards the rest of Xa genes formed the most frequent (41%) and widely distributed pathotype. The vast majority of the assayed Xoo isolates were incompatible with one or more Xa genes. Exceptionally, the isolates of pathotype XI were virulent on all Xa genes, but have restricted distribution. Considering the individual R-genes, Xa21 appeared as the most broadly effective, conferring resistance against 88 % of the isolates, followed in decreasing order by xa13 (84 %), xa8 (64 %), xa5 (30 %), Xa7 (17 %) and Xa4 (14 %). Fifty isolates representing all the eleven pathotypes were analyzed by southern hybridization to determine their genetic relatedness using the IS1112 repeat element of Xoo. Isolates belonging to pathotype XI were the most divergent. The results suggest that one RFLP haplotype that is widely distributed all over India and is represented in strains from five different pathotypes might be an ancestral haplotype. A rice line with xa5, xa13 and Xa21 resistance genes is resistant to all strains, including those belonging to pathotype XI. This three gene combination appears to be the most suitable Xa gene combination to be deployed in Indian rice cultivars. PMID:24312391

  7. Bilirubin Oxidase Activity of Bacillus subtilis CotA

    PubMed Central

    Sakasegawa, Shin-ichi; Ishikawa, Hidehiko; Imamura, Shigeyuki; Sakuraba, Haruhiko; Goda, Shuichiro; Ohshima, Toshihisa

    2006-01-01

    The spore coat protein CotA from Bacillus subtilis was previously identified as a laccase. We have now found that CotA also shows strong bilirubin oxidase activity and markedly higher affinity for bilirubin than conventional bilirubin oxidase. This is the first characterization of bilirubin oxidase activity in a bacterial protein. PMID:16391148

  8. Monoclonal antibodies to the alternative oxidase of higher plant mitochondria

    Microsoft Academic Search

    T. E. Elthon; R. L. Nickels; L. McIntosh

    1989-01-01

    The higher plant mitochondrial electron transport chain contains, in addition to the cytochrome chain which terminates with cytochrome oxidase, an alternative pathway that terminates with an alternative oxidase. The alternative oxidase of Sauromatum guttatum Schott has recently been identified as a cluster of proteins with apparent M{sub r} of 37, 36, and 35 kilodaltons (kD). Monoclonal antibodies have now been

  9. Cyclopiazonic Acid Biosynthesis of Aspergillus flavus and Aspergillus oryzae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cyclopiazonic acid (CPA) is an indole-tetramic acid neurotoxin produced by some of the same strains of A. flavus that produce aflatoxins and by some Aspergillus oryzae strains. Despite its discovery 40 years ago, few reviews of its toxicity and biosynthesis have been reported. This review examines w...

  10. Genetic Structure and Diversity in Oryza sativa L

    Microsoft Academic Search

    Amanda J. Garris; Thomas H. Tai; Jason Coburn; Steve Kresovich; Susan McCouch

    2005-01-01

    The population structure of domesticated species is influenced by the natural history of the populations of predomesticated ancestors, as well as by the breeding system and complexity of the breeding practices exercised by humans. Within Oryza sativa, there is an ancient and well-established divergence between the two major subspecies, indica and japonica, but finer levels of genetic structure are suggested

  11. WHOLE GENOME COMPARISON OF ASPERGILLUS FLAVUS AND A. ORYZAE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is a plant and animal pathogen that also produces the potent carcinogen aflatoxin. Aspergillus oryzae is a closely related species that has been used for centuries in the food fermentation industry and is generally regarded as safe (GRAS). Whole genome sequences for these two fu...

  12. Indoloditerpenes from an algicolous isolate of Aspergillus oryzae

    Microsoft Academic Search

    Ming-Feng Qiao; Nai-Yun Ji; Xiang-Hong Liu; Ke Li; Qing-Mei Zhu; Qin-Zhao Xue

    2010-01-01

    Two new indoloditerpene derivatives asporyzin A (1) and asporyzin B (2), one new indoloditerpene asporyzin C (3), and three known related indoloditerpenes JBIR-03 (4), emindole SB (5), and emeniveol (6) were isolated from an endophytic fungus Aspergillus oryzae, isolated from the marine red alga Heterosiphonia japonica. Their structures were unambiguously established by spectroscopic techniques. In addition, all the isolates were

  13. CBS domain-containing proteins are Rhizopus oryzae ferrioxamine receptors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Iron-overload patients treated with deferoxamine are uniquely susceptible to mucormycosis, because Rhizopus spp. can obtain iron from ferrioxamine (deferoxamine + Fe**3+). Previously we have identified two closely related, ferrioxamine-inducible R. oryzae genes (FOB1 and FOB2) in which ...

  14. Galacto-oligosaccharide synthesis by immobilized Aspergillus oryzae ?-galactosidase

    Microsoft Academic Search

    Ruchi Gaur; Hema Pant; Ruchi Jain; S. K. Khare

    2006-01-01

    Aspergillus oryzae ?-galactosidase was immobilized by three different techniques, namely adsorption on celite, covalent coupling to chitosan and aggregation by cross-linking. These techniques were compared in terms of the yield of immobilized preparation, enzymatic characteristics, stability and efficiency in oligosaccharide synthesis. Immobilization led to increase in Km in each case. Immobilization on chitosan gave maximum enzyme yield and oligosaccharide synthesis.

  15. In vitro induction of phosphinothricin tolerance in rice (Oryza sativa)

    Microsoft Academic Search

    Yu-Wen Liu; Wei-Yu Chou; Ching-Yuh Wang

    Liu, Y. W., Chou, W. Y., and Wang, C. Y. * 2005. In vitro induction of phosphinothricin tolerance in rice (Oryza sativa). Plant Prot. Bull. 47: 47 - 58 In vitro culture of rice buds has been developed to induce tolerance to phos- phinothricin (PPT), i.e., the glufosinate herbicide. Treatment at stage I of tissue culture with PPT concentrations higher

  16. Could abiotic stress tolerance in wild relatives of rice be used to improve Oryza sativa?

    PubMed

    Atwell, Brian J; Wang, Han; Scafaro, Andrew P

    2014-02-01

    Oryza sativa and Oryza glaberrima have been selected to acquire and partition resources efficiently as part of the process of domestication. However, genetic diversity in cultivated rice is limited compared to wild Oryza species, in spite of 120,000 genotypes being held in gene banks. By contrast, there is untapped diversity in the more than 20 wild species of Oryza, some having been collected from just a few coastal locations (e.g. Oryza schlechteri), while others are widely distributed (e.g. Oryza nivara and Oryza rufipogon). The extent of DNA sequence diversity and phenotypic variation is still being established in wild Oryza, with genetic barriers suggesting a vast range of morphologies and function even within species, such as has been demonstrated for Oryza meridionalis. With increasing climate variability and attempts to make more marginal land arable, abiotic and biotic stresses will be managed over the coming decades by tapping into the genetic diversity of wild relatives of O. sativa. To help create a more targeted approach to sourcing wild rice germplasm for abiotic stress tolerance, we have created a climate distribution map by plotting the natural occurrence of all Oryza species against corresponding temperature and moisture data. We then discuss interspecific variation in phenotype and its significance for rice, followed by a discussion of ways to integrate germplasm from wild relatives into domesticated rice. PMID:24388514

  17. Effect of anti-inflammatory drugs on xanthine oxidase and xanthine oxidase induced depolymerization of hyaluronic acid

    Microsoft Academic Search

    G. Carlin; R. Djursäter; G. Smedegård; B. Gerdin

    1985-01-01

    The inhibitory effect of various anti-inflammatory drugs on the xanthine oxidase derived depolymerization of hyaluronic acid was studied. The depolymerization was assayed by repeated viscosity measurements. By using a low xanthine oxidase activity, the decrease in viscosity with time followed first order reaction kinetics and was therefore suitable for kinetic analysis. The xanthine oxidase activity was monitored by assay of

  18. Suicide Inactivation of Catechol 2,3-Dioxygenase from Pseudomonas putida mt-2 by 3-Halocatechols

    PubMed Central

    Bartels, Iris; Knackmuss, Hans-Joachim; Reineke, Walter

    1984-01-01

    The inactivation of catechol 2,3-dioxygenase from Pseudomonas putida mt-2 by 3-chloro- and 3-fluorocatechol and the iron-chelating agent Tiron (catechol-3,5-disulfonate) was studied. Whereas inactivation by Tiron is an oxygen-independent and mostly reversible process, inactivation by the 3-halocatechols was only observed in the presence of oxygen and was largely irreversible. The rate constants for inactivation (K2) were 1.62 × 10?3 sec?1 for 3-chlorocatechol and 2.38 × 10?3 sec?1 for 3-fluorocatechol. The inhibitor constants (Ki) were 23 ?M for 3-chlorocatechol and 17 ?M for 3-fluorocatechol. The kinetic data for 3-fluorocatechol could only be obtained in the presence of 2-mercaptoethanol. Besides inactivated enzyme, some 2-hydroxyhexa-2,4-diendioic acid was formed from 3-chlorocatechol, suggesting 5-chloroformyl-2-hydroxypenta-2,4-dienoic acid as the actual suicide product of meta-cleavage. A side product of 3-fluorocatechol cleavage is a yellow compound with the spectral characteristics of a 2-hydroxy-6-oxohexa-2,4-dienoic acid indicating 1,6-cleavage. Rates of inactivation by 3-fluorocatechol were reduced in the presence of superoxide dismutase, catalase, formate, and mannitol, which implies that superoxide anion, hydrogen peroxide, and hydroxyl radical exhibit additional inactivation. PMID:16346490

  19. Degradation of Phenolic Compounds and Ring Cleavage of Catechol by Phanerochaete chrysosporium

    PubMed Central

    Leatham, Gary F.; Crawford, R. L.; Kirk, T. Kent

    1983-01-01

    POL-88, a mutant of the white-rot fungus Phanerochaete chrysosporium, was selected for diminished phenol-oxidizing enzyme activity. A wide variety of phenolic compounds were degraded by ligninolytic cultures of this mutant. With several o-diphenolic substrates, degradation intermediates were produced that had UV spectra consistent with muconic acids. Extensive spectrophotometric and polarographic assays failed to detect classical ring-cleaving dioxygenases in cell homogenates or in extracts from ligninolytic cultures. Even so, a sensitive carrier-trapping assay showed that intact cultures degraded [U-14C]catechol to [14C]muconic acid, establishing the presence of a system capable of 1,2-intradiol fission. Significant accumulation of [14C]muconic acid into carrier occurred only when evolution of 14CO2 from [14C]catechol was inhibited by treating cultures with excess nutrient nitrogen (e.g., l-glutamic acid) or with cycloheximide. l-Glutamic acid is known from past work to repress the ligninolytic system in P. chrysosporium and to mimic the effect of cycloheximide. The results here indicate, therefore, that the enzyme system responsible for degrading ring-cleavage products to CO2 turns over faster than does the system responsible for ring cleavage. PMID:16346340

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

  1. [Catechol siderophore, produced by thermoresistent strain of Bacillus licheniformis VK21].

    PubMed

    Temirov, Iu V; Esikova, T Z; Kashparov, I A; Balashova, T A; Vinokurov, L M; Alakhov, Iu B

    2003-01-01

    Thermophilic and thermoresistant strains of bacilli were screened on a medium containing Chrome Azurol S for producers of siderophores. It was found that the Bacillus licheniformis VK21 strain dramatically increases secretion of the metabolite, a chelator of Fe3+, in response to addition of manganese(II) salts. The growth of the producer on a minimum medium containing MnSO4 under the conditions of iron deficiency is accompanied by the accumulation of a catechol product, the content of which reaches a maximum at the beginning of the stationary growth phase of culture. In the presence of FeCl3, the amount of the catechol product in the medium considerably decreases. The siderophore, called SVK21, was isolated from the cultural medium and purified by reversed phase HPLC, and its siderophore function was confirmed by the test for the restoration of growth of producer cells in a medium containing EDTA. The UV spectrum of the siderophore has absorption maxima at 248 and 315 nm. According to amino acid analysis and NMR spectrometry, the metabolite SVK21 is 2,3-dihydroxybenzoyl-glycyl-threonine. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2003, vol. 29, no. 6; see also http://www.maik.ru. PMID:14743533

  2. Formation of Catechols via Removal of Acid Side Chains from Ibuprofen and Related Aromatic Acids

    PubMed Central

    Murdoch, Robert W.; Hay, Anthony G.

    2005-01-01

    Although ibuprofen [2-(4-isobutylphenyl)-propionic acid] is one of the most widely consumed drugs in the world, little is known regarding its degradation by environmental bacteria. Sphingomonas sp. strain Ibu-2 was isolated from a wastewater treatment plant based on its ability to use ibuprofen as a sole carbon and energy source. A slight preference toward the R enantiomer was observed, though both ibuprofen enantiomers were metabolized. A yellow color, indicative of meta-cleavage, accumulated transiently in the culture supernatant when Ibu-2 was grown on ibuprofen. When and only when 3-flurocatechol was used to poison the meta-cleavage system, isobutylcatechol was identified in the culture supernatant via gas chromatography-mass spectrometry analysis. Ibuprofen-induced washed-cell suspensions also metabolized phenylacetic acid and 2-phenylpropionic acid to catechol, while 3- and 4-tolylacetic acids and 2-(4-tolyl)-propionic acid were metabolized to the corresponding methyl catechols before ring cleavage. These data suggest that, in contrast to the widely distributed coenzyme A ligase, homogentisate, or homoprotocatechuate pathway for metabolism of phenylacetic acid and similar compounds, Ibu-2 removes the acidic side chain of ibuprofen and related compounds prior to ring cleavage. PMID:16204529

  3. Flavin Amine Oxidases from the Monoamine Oxidase Structural Family Utilize a Hydride Transfer Mechanism 

    E-print Network

    Henderson Pozzi, Michelle

    2011-08-08

    The amine oxidase family of enzymes has been the center of numerous mechanistic studies because of the medical relevance of the reactions they catalyze. This study describes transient and steady-state kinetic analyses of ...

  4. Relationship between Disease Resistance and Rice Oxalate Oxidases in Transgenic Rice

    PubMed Central

    Zhang, Xian Yong; Nie, Zhuan Hua; Wang, Wen Juan; Leung, David W. M.; Xu, Da Gao; Chen, Bai Ling; Chen, Zhe; Zeng, Lie Xian; Liu, E. E.

    2013-01-01

    Differential expression of rice oxalate oxidase genes (OsOxO1-4) in rice leaves (Oryza sativa L.) in response to biotic stress was assayed using RT-PCR. OsOxO4 was induced transiently at 12 h in plants inoculated with the pathogens of bacterial blight and that of the wounding control. Inoculation with the rice blast pathogen induced OsOxO2 expression compared to the mock spray control. Overexpressing OsOxO1 or OsOxO4 in rice resulted in elevated transcript levels of the respective transgene as well as OsOxO3 in leaves compared to that in untransformed wild type (WT). In a line of RNA-i transgenic rice plants (i-12), expression of all four OsOxO genes except that of OsOxO2 was severely inhibited. Oxalate oxidase (OxO, EC 1.2.3.4) activity in plants overexpressing OsOxO1 or OsOxO4 was substantially higher than that in WT and the RNA-i lines. It was found that transgenic rice plants with substantially higher OxO activity were not more resistant to rice blast and bacterial blight than WT. In contrast, some RNA-i lines with less OxO activity seemed to be more resistant to rice blast while some overexpressing lines were more susceptible to rice blast than WT. Therefore, OxO might not be a disease resistance factor in rice. PMID:24205207

  5. Search for and Analysis of Single Nucleotide Polymorphisms (SNPs) in Rice (Oryza sativa, Oryza rufipogon) and Establishment of SNP Markers

    Microsoft Academic Search

    Shinobu Nasu; Junko Suzuki; Rieko Ohta; Kana Hasegawa; Rika Yui; Noriyuki Kitazawa; Lisa Monna; Yuzo Minobe

    2002-01-01

    We searched for SNPs in 417 regions distributed throughout the genome of three Oryza sativa ssp. japonica cultivars, two indica cultivars, and a wild rice (O. rufipogon). We found 2800 SNPs in approxi- mately 250,000 aligned bases for an average of one SNP every 89 bp, or one SNP every 232 bp between two randomly selected strains. Graphic representation of

  6. Genetic analysis of agronomic and grain quality traits in an Oryza sativa/Oryza nivara advanced backcross population

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice wild relatives are a potential source of genetic diversity for cultivated rice improvement. Approximately 175 BC2F3:4 M202 (Oryza sativa L.)/O. nivara Sharma & Shastry (IRGC 100195) advanced backcross progeny were genotyped with 150 SSR (single sequence repeat) markers, and phenotyped for five...

  7. Evaluating the effects of cold water diffusates against Xanthomonas oryzae Pv. Oryzae causing bacterial leaf blight (BLB) in rice

    Microsoft Academic Search

    Rukhsana Jabeen; Muhammad Ashraf; Iftikhar Ahmad

    2009-01-01

    The crude extracts of 63 plants were used for testing antibacterial activity against Xanthmonas oryazae Pv. oryzae that causes bacterial leaf blight (BLB) in rice plants. Only ten aqueous extracts of botanicals (Thuja orientalis, Prunus domestica, Citrus limon, Allium sativum, Vitis vinefera, Mangifera indica, Phyllanthus emblica, and Terminalia chebula) showed maximum activity against Xanthmonas oryazae in a plate agar diffusion

  8. Novel lead compound optimization and synthesized based on the target structure of Xanthomonas oryzae pv. oryzae GlmU.

    PubMed

    Qi, Xiaojuan; Deng, Wenjun; Gao, Min; Mao, Bangqiang; Xu, Shengzhen; Chen, Changshui; Zhang, Qingye

    2015-07-01

    Bacterial leaf blight, caused by Xanthomonas oryzae pv. oryzae, is one of the most destructive diseases of rice worldwide. N-acetylglucosamine-1-phosphate uridyltransferase (GlmU) was an attractive target for the development of antimicrobial agents. To develop novel, more potent and even more selective inhibitors of the uridyltransferase activity of Xanthomonas oryzae pv. oryzae GlmU (Xo-GlmU), three types of novel target compounds were optimized and synthesized based on the Xo-GlmU structure in this study. The biological testing results showed that all of the target compounds displayed the higher inhibition than the lead compound with the IC50 values in the 10.82-23.31?µM range, and the inhibition rates were increased by 30%-67%. The binding mode and the possible inhibitory mechanism of the target compounds in the active site were also analyzed by the molecular docking based on the uridyltransferase active site of Xo-GlmU. PMID:26071803

  9. A theoretical study of the dioxygen activation by glucose oxidase and copper amine oxidase

    Microsoft Academic Search

    Rajeev Prabhakar; Per E. M. Siegbahn; Boris F. Minaev

    2003-01-01

    Glucose oxidase (GO) and copper amine oxidase (CAO) catalyze the reduction of molecular oxygen to hydrogen peroxide. If a closed-shell cofactor (like FADH2 in GO and topaquinone (TPQ) in CAO) is electron donor in dioxygen reduction, the formation of a closed-shell species (H2O2) is a spin forbidden process. Both in GO and CAO, formation of a superoxide ion that leads

  10. Field evaluation of seed production, shattering, and dormancy in hybrid populations of transgenic rice ( Oryza sativa) and the weed, red rice ( Oryza sativa)

    Microsoft Academic Search

    James Oard; Marc Alan Cohn; Steve Linscombe; David Gealy; Kenneth Gravois

    2000-01-01

    The genetic and agronomic consequences of transferring glufosinate (Liberty™) herbicide resistance from transgenic rice (Oryza sativa L.) lines to the noxious weed red rice (Oryza sativa L.) were evaluated under field conditions. Replicated field trials in Louisiana (LA) and Arkansas (AR) were conducted in 1997 to evaluate ten vegetative and reproductive traits of eight F2 populations produced from controlled crosses

  11. Monoamine Oxidase Expression During Development and Aging

    Microsoft Academic Search

    Antonietta Nicotra; Federica Pierucci; Hasan Parvez; Ornella Senatori

    2004-01-01

    Monoamine oxidase (MAO) isoenzymes play a major role in regulating the concentration of several bioactive amines, including serotonin and catecholamines. Both in the nervous system and in peripheral organs, MAOs can potentially modulate all the processes involving these bioactive amines. In the present article, we review some of the most significant articles published so far on changes in MAOs during

  12. Myeloperoxidase-oxidase oxidation of cysteamine.

    PubMed Central

    Svensson, B E; Lindvall, S

    1988-01-01

    Cysteamine oxidation was shown to be catalysed by nanomolar concentrations of myeloperoxidase in a peroxidase-oxidase reaction, i.e. an O2-consuming oxidation of a compound catalysed by peroxidase without H2O2 addition. When auto-oxidation of the thiol was prevented by the metal-ion chelator diethylenetriaminepenta-acetic acid, native, but not heat-inactivated, myeloperoxidase induced changes in the u.v.-light-absorption spectrum of cysteamine. These changes were consistent with disulphide (cystamine) formation. Concomitantly, O2 was consumed and superoxide radical anion formation could be detected by Nitro Blue Tetrazolium reduction. Both superoxide dismutase and catalase inhibited the reaction, whereas the hydroxyl-radical scavengers mannitol and ethanol did not. O2 consumption increased with increasing pH (between pH 6.0 and 8.0), and 50% inhibition was exhibited by about 3 mM-NaCl at pH 7.0 and by about 100 mM-NaCl at pH 8.0. Cysteamine was about 5 times as active (in terms of increased O2 consumption at pH 7.5) as the previously reported peroxidase-oxidase substrates NADPH, dihydroxyfumaric acid and indol-3-ylacetic acid. A possible reaction pathway for the myeloperoxidase-oxidase oxidation of cysteamine is discussed. These results indicate that cysteamine is a very useful substrate for studies on myeloperoxidase-oxidase activity. PMID:2829860

  13. Polyphenol oxidase activity in annual forage clovers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Polyphenol oxidase (PPO)-mediated phenol reactions in red clover (Trifolium pratense L.) bind forage protein and reduce proteolysis, producing beneficial effects on forage protein degradability, silage fermentation, and soil-N cycling. We evaluated PPO activity in seven previously untested annual c...

  14. Combination Patterns of Major R Genes Determine the Level of Resistance to the M. oryzae in Rice (Oryza sativa L.)

    PubMed Central

    Yu, Ling; Pan, Cunhong; Li, Yuhong; Zhang, Xiaoxiang; Liu, Guangqing; Dai, Zhengyuan; Pan, Xuebiao; Li, Aihong

    2015-01-01

    Rice blast caused by Magnaporthe oryzae is the most devastating disease of rice and poses a serious threat to world food security. In this study, the distribution and effectiveness of 18 R genes in 277 accessions were investigated based on pathogenicity assays and molecular markers. The results showed that most of the accessions exhibited some degree of resistance (resistance frequency, RF >50%). Accordingly, most of the accessions were observed to harbor two or more R genes, and the number of R genes harbored in accessions was significantly positively correlated with RF. Some R genes were demonstrated to be specifically distributed in the genomes of rice sub-species, such as Pigm, Pi9, Pi5 and Pi1, which were only detected in indica-type accessions, and Pik and Piz, which were just harbored in japonica-type accessions. By analyzing the relationship between R genes and RF using a multiple stepwise regression model, the R genes Pid3, Pi5, Pi9, Pi54, Pigm and Pit were found to show the main effects against M. oryzae in indica-type accessions, while Pita, Pb1, Pik, Pizt and Pia were indicated to exhibit the main effects against M. oryzae in japonica-type accessions. Principal component analysis (PCA) and cluster analysis revealed that combination patterns of major R genes were the main factors determining the resistance of rice varieties to M. oryzae, such as ‘Pi9+Pi54’, ‘Pid3+Pigm’, ‘Pi5+Pid3+Pigm’, ‘Pi5+Pi54+Pid3+Pigm’, ‘Pi5+Pid3’ and ‘Pi5+Pit+Pid3’ in indica-type accessions and ‘Pik+Pib’, ‘Pik+Pita’, ‘Pik+Pb1’, ‘Pizt+Pia’ and ‘Pizt+Pita’ in japonica-type accessions, which were able to confer effective resistance against M. oryzae. The above results provide good theoretical support for the rational utilization of combinations of major R genes in developing rice cultivars with broad-spectrum resistance. PMID:26030358

  15. Combination Patterns of Major R Genes Determine the Level of Resistance to the M. oryzae in Rice (Oryza sativa L.).

    PubMed

    Wu, Yunyu; Xiao, Ning; Yu, Ling; Pan, Cunhong; Li, Yuhong; Zhang, Xiaoxiang; Liu, Guangqing; Dai, Zhengyuan; Pan, Xuebiao; Li, Aihong

    2015-01-01

    Rice blast caused by Magnaporthe oryzae is the most devastating disease of rice and poses a serious threat to world food security. In this study, the distribution and effectiveness of 18 R genes in 277 accessions were investigated based on pathogenicity assays and molecular markers. The results showed that most of the accessions exhibited some degree of resistance (resistance frequency, RF >50%). Accordingly, most of the accessions were observed to harbor two or more R genes, and the number of R genes harbored in accessions was significantly positively correlated with RF. Some R genes were demonstrated to be specifically distributed in the genomes of rice sub-species, such as Pigm, Pi9, Pi5 and Pi1, which were only detected in indica-type accessions, and Pik and Piz, which were just harbored in japonica-type accessions. By analyzing the relationship between R genes and RF using a multiple stepwise regression model, the R genes Pid3, Pi5, Pi9, Pi54, Pigm and Pit were found to show the main effects against M. oryzae in indica-type accessions, while Pita, Pb1, Pik, Pizt and Pia were indicated to exhibit the main effects against M. oryzae in japonica-type accessions. Principal component analysis (PCA) and cluster analysis revealed that combination patterns of major R genes were the main factors determining the resistance of rice varieties to M. oryzae, such as 'Pi9+Pi54', 'Pid3+Pigm', 'Pi5+Pid3+Pigm', 'Pi5+Pi54+Pid3+Pigm', 'Pi5+Pid3' and 'Pi5+Pit+Pid3' in indica-type accessions and 'Pik+Pib', 'Pik+Pita', 'Pik+Pb1', 'Pizt+Pia' and 'Pizt+Pita' in japonica-type accessions, which were able to confer effective resistance against M. oryzae. The above results provide good theoretical support for the rational utilization of combinations of major R genes in developing rice cultivars with broad-spectrum resistance. PMID:26030358

  16. Detection of xanthine oxidase in human plasma.

    PubMed

    Newaz, M A; Adeeb, N N

    1998-03-01

    Xanthine oxidase is a highly versatile enzyme which is widely distributed among various species. Though the presence of the enzyme in serum is not yet established, high antibody titre of this enzyme has been reported. Xanthine oxidase is thought to be the principal source of free radical generation via degradation of nucleotides to the end product, uric acid. The aim of this study was to detect xanthine oxidase activity in human plasma and report any significant relationships found between its activity and variables such as race, age and sex for the sample size studied. Forty six normal healthy individuals (14 males and 32 females) were studied. The enzyme activity was measured by a spectrophotometric method whereby the reduction of ferricytochrome c by free radicals was calculated and expressed as nmol O2 production/ml/min. Results obtained showed that there was a positive relationship between xanthine oxidase activity with age (r = 0.415, p < 0.05) and weight (r = 0.369, p < 0.05) in the normal individual. For the age group 30-39 yrs (n = 11), a higher enzyme activity was observed in males (2.71 +/- 1.44) as compared to females (2.34 +/- 1.23) but it was not significant (p = 0.53). For racial distribution, the Malays [M] have a higher enzyme activity (2.65 +/- 0.86, N = 32) than their Indian [I] (2.27 +/- 0.58; N = 7) and Chinese counterparts [C] (1.44 +/- 1.22; N = 7) but this was also not statistically significant (M vs I: p = 0.39; M vs C: p = 0.07; I vs C: p = 0.16). In conclusion this study showed that there is a measurable amount of xanthine oxidase activity in the human plasma. PMID:10968141

  17. Estrogen 2- and 4Hydroxylase Activity, Catechol Estrogen Formation, and Implications for Estrogen Carcinogenesis in the Hamster Kidney1

    Microsoft Academic Search

    Sara Antonia Li; John K. Klicka; Jonathan J. Li

    Estrogen 2- and 4-hydroxylase (ESH), a microsomal enzyme which mediates the formation of catechol estrogens, has been studied in the kidneys of castrated male Syrian hamsters, a species uniquely susceptible to induction of renal carcinomas by both steroidal and stilbene estrogens. The apparent Kâ€?, for estrone was 17.0 MM,and V,â\\

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

    EPA Science Inventory

    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...

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

    EPA Science Inventory

    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...

  20. Iron transport-mediated antibacterial activity of and development of resistance to hydroxamate and catechol siderophore-carbacephalosporin conjugates.

    PubMed Central

    Minnick, A A; McKee, J A; Dolence, E K; Miller, M J

    1992-01-01

    Peptides containing residues of N5-acetyl-N5-hydroxy-L-ornithine were evaluated as potential artificial siderophores of beta-lactam-hypersusceptible Escherichia coli X580. Only those peptides which were capable of forming a hexadentate complex around ferric iron, which is analogous to the natural siderophore ferrichrome, were able to reverse the growth inhibition effects of the ferric iron chelator ethylenediamine di(o-hydroxyphenylacetic acid). A synthetic bis(catechol) spermidine derivative, similar to the natural siderophores enterobactin and agrobactin, also exhibited siderophore activity with this strain. Conjugation of the N5-acetyl-N5-hydroxy-L-ornithine tripeptide and the bis(catechol) siderophore to the potent carbacephalosporin loracarbef and closely related analogs provided compounds which exhibited antibacterial activity against E. coli X580. As was observed with the naturally occurring albomycins, the initial bactericidal effect was followed by the appearance of survivors that were resistant to the test compound. An enhanced killing effect was observed when the parent was incubated simultaneously with hydroxamate and catechol siderophore-antibiotic conjugates. Natural and synthetic siderophore growth promotion experiments with survivors resistant to the conjugates strongly suggested that disabled ferrichrome and enterobactin-catechol assimilation mechanisms may be responsible for the observed resistance. One isolated survivor was postulated to be a tonB mutant. The antibacterial activities of the described siderophore-carbacephalosporin conjugates appear to be related to an iron transport assimilation mechanism and would not have been detected during routine MIC testing procedures. PMID:1503447

  1. Characterization and genetic analysis of a very high tillering and dwarf rice (Oryza sativa L.) mutant 

    E-print Network

    Mani, Dhananjay

    2009-05-15

    . Oryza sativa is cultivated throughout the world but Oryza glaberrima is cultivated mostly in West Africa. Oryza sativa is further classified into three sub-species based on geographical distribution and morphological traits: japonica, indica..., and javanica (Takahashi, 1984). Japonica and indica are mainly grown in temperate and tropical/sub-tropical areas, respectively. Javanica is also known as ?tropical japonica? (Mae, 1997) commonly grown in the U.S. The first trial planting of rice in the U...

  2. Site-specific Inhibitory Mechanism for Amyloid ?42 Aggregation by Catechol-type Flavonoids Targeting the Lys Residues*

    PubMed Central

    Sato, Mizuho; Murakami, Kazuma; Uno, Mayumi; Nakagawa, Yu; Katayama, Sumie; Akagi, Ken-ichi; Masuda, Yuichi; Takegoshi, Kiyonori; Irie, Kazuhiro

    2013-01-01

    The aggregation of the 42-residue amyloid ?-protein (A?42) is involved in the pathogenesis of Alzheimer disease (AD). Numerous flavonoids exhibit inhibitory activity against A?42 aggregation, but their mechanism remains unclear in the molecular level. Here we propose the site-specific inhibitory mechanism of (+)-taxifolin, a catechol-type flavonoid, whose 3?,4?-dihydroxyl groups of the B-ring plays a critical role. Addition of sodium periodate, an oxidant, strengthened suppression of A?42 aggregation by (+)-taxifolin, whereas no inhibition was observed under anaerobic conditions, suggesting the inhibition to be associated with the oxidation to form o-quinone. Because formation of the A?42-taxifolin adduct was suggested by mass spectrometry, A?42 mutants substituted at Arg5, Lys16, and/or Lys28 with norleucine (Nle) were prepared to identify the residues involved in the conjugate formation. (+)-Taxifolin did not suppress the aggregation of A?42 mutants at Lys16 and/or Lys28 except for the mutant at Arg5. In addition, the aggregation of A?42 was inhibited by other catechol-type flavonoids, whereas that of K16Nle-A?42 was not. In contrast, some non-catechol-type flavonoids suppressed the aggregation of K16Nle-A?42 as well as A?42. Furthermore, interaction of (+)-taxifolin with the ?-sheet region in A?42 was not observed using solid-state NMR unlike curcumin of the non-catechol-type. These results demonstrate that catechol-type flavonoids could specifically suppress A?42 aggregation by targeting Lys residues. Although the anti-AD activity of flavonoids has been ascribed to their antioxidative activity, the mechanism that the o-quinone reacts with Lys residues of A?42 might be more intrinsic. The Lys residues could be targets for Alzheimer disease therapy. PMID:23792961

  3. Self-Assembly of Catecholic Moiety-Containing Cationic Random Acrylic Copolymers.

    PubMed

    Taresco, Vincenzo; Gontrani, Lorenzo; Crisante, Fernanda; Francolini, Iolanda; Martinelli, Andrea; D'Ilario, Lucio; Bordi, Federico; Piozzi, Antonella

    2015-07-01

    Amphiphilic polyelectrolytes (APEs), exhibiting particular self-association properties in aqueous media, can be used in different industrial applications, including drug delivery systems. Their typical core-shell structure (micelle) depends on the balance of interactions between hydrophobic and ionizable monomer units. In this work, the structure of amphiphilic cationic random copolymers, obtained by employing different molar ratios of two acrylic monomers, one bearing in the side chain a tertiary amine (N,N-diethylethylendiamine, DED) and the other one a hydrophobic catecholic group (hydroxytyrosol, HTy), was investigated by atomistic molecular dynamics (MD) simulation, (1)H NMR analysis, dynamic light scattering (DLS), and zeta potential measurements. The structures of p(AcDED-co-AcHTy) copolymers were compared with that of the cationic homopolymer (pAcDED). MD simulation showed a chain folding in water solution of all polymer materials consistent with the degree of hydrophobicity of the chain, that increases with the number of aromatic residues. This phenomenon was induced by the interaction between the charged amine groups with water and by the associated attraction between aromatic rings inside the molecule. In addition, the p(AcDED-co-AcHTy) 70/30 copolymer had a marked tendency to self-assemble as shown by the radial distribution function among catechol carbon atoms. Electrical conductivity measurements evidenced a micellar arragment for all of the synthesized copolymers, and specially for p(AcDED-co-AcHTy) 70/30, a flower micelle structure seem to be more likely. The stacking interactions among catecholic groups present in the side chain of the copolymers reduced the size and charge density specially for the p(AcDED-co-AcHTy) 70/30 copolymer. Finally, the good antimicrobial activity of all copolymers confirmed the right reached amphiphilic balance. Indeed, a considerable reduction of the minimum inhibitory concentration (from 100 ?g/mL to 40 ?g/mL for pAcDED and p(AcDED-co-AcHTy) 70/30, respectively) was obtained by introducing a hydrophobic group molar fraction of 0.3. PMID:26075948

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

    SciTech Connect

    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 formation and protein aggregation.

  5. Urinary excretion of phenol, catechol, hydroquinone, and muconic acid by workers occupationally exposed to benzene

    PubMed Central

    Rothman, N.; Bechtold, W. E.; Yin, S. N.; Dosemeci, M.; Li, G. L.; Wang, Y. Z.; Griffith, W. C.; Smith, M. T.; Hayes, R. B.

    1998-01-01

    OBJECTIVES: Animal inhalation studies and theoretical models suggest that the pattern of formation of benzene metabolites changes as exposure to benzene increases. To determine if this occurs in humans, benzene metabolites in urine samples collected as part of a cross sectional study of occupationally exposed workers in Shanghai, China were measured. METHODS: With organic vapour monitoring badges, 38 subjects were monitored during their full workshift for inhalation exposure to benzene. The benzene urinary metabolites phenol, catechol, hydroquinone, and muconic acid were measured with an isotope dilution gas chromatography mass spectroscopy assay and strongly correlated with concentrations of benzene air. For the subgroup of workers (n = 27) with urinary phenol > 50 ng/g creatinine (above which phenol is considered to be a specific indicator of exposure to benzene), concentrations of each of the four metabolites were calculated as a ratio of the sum of the concentrations of all four metabolites (total metabolites) and were compared in workers exposed to > 25 ppm v < or = 25 ppm. RESULTS: The median, 8 hour time weighted average exposure to benzene was 25 ppm. Relative to the lower exposed workers, the ratio of phenol and catechol to total metabolites increased by 6.0% (p = 0.04) and 22.2% (p = 0.007), respectively, in the more highly exposed workers. By contrast, the ratio of hydroquinone and muconic acid to total metabolites decreased by 18.8% (p = 0.04) and 26.7% (p = 0.006), respectively. Similar patterns were found when metabolite ratios were analysed as a function of internal benzene dose (defined as total urinary benzene metabolites), although catechol showed a more complex, quadratic relation with increasing dose. CONCLUSIONS: These results, which are consistent with previous animal studies, show that the relative production of benzene metabolites is a function of exposure level. If the toxic benzene metabolites are assumed to be derived from hydroquinone, ring opened products, or both, these results suggests that the risk for adverse health outcomes due to exposure to benzene may have a supralinear relation with external dose, and that linear extrapolation of the toxic effects of benzene in highly exposed workers to lower levels of exposure may underestimate risk.   PMID:9930093

  6. Lysyl oxidase expression and inhibition in uveal melanoma.

    PubMed

    Abourbih, Daniel A; Di Cesare, Sebastian; Orellana, Maria E; Antecka, Emilia; Martins, Claudia; Petruccelli, Luca A; Burnier, Miguel N

    2010-04-01

    Lysyl oxidase is a marker of poor prognosis in several malignancies and is hypothesized to promote a migratory phenotype in hypoxic breast carcinomas. This study aims to characterize the expression of the lysyl oxidase and lysyl oxidase-like proteins in human uveal melanoma cell lines and archival choroidal melanomas using immunohistochemistry. The transcriptional control of lysyl oxidase will also be investigated under simulated hypoxic conditions using cobalt chloride. Lastly, changes in cellular proliferation and invasion will be assessed after the treatment of cell lines with beta-aminopropionitrile, a lysyl oxidase catalytic inhibitor. Retrospective analysis of lysyl oxidase expression in primary human uveal melanoma showed 82% (27 of 33) of tumors being stained positive. High lysyl oxidase expression correlated with the aggressive epithelioid cell type and was associated with shorter metastasis-free survival. Simulated hypoxia resulted in a significant increase in lysyl oxidase mRNA expression. Inhibiting lysyl oxidase's catalytic activity significantly reduced cellular invasion but had no effect on cell proliferation. Our study is the first to show lysyl oxidase expression in primary choroidal melanomas. This protein may represent a potential therapeutic target that warrants further study in this malignancy. PMID:20179655

  7. Ultraviolet resonance Raman study of drug binding in dihydrofolate reductase, gyrase, and catechol O-methyltransferase.

    PubMed Central

    Couling, V W; Fischer, P; Klenerman, D; Huber, W

    1998-01-01

    This paper presents a study of the use of ultraviolet resonance Raman (UVRR) spectroscopic methods as a means of elucidating aspects of drug-protein interactions. Some of the RR vibrational bands of the aromatic amino acids tyrosine and tryptophan are sensitive to the microenvironment, and the use of UV excitation radiation allows selective enhancement of the spectral features of the aromatic amino acids, enabling observation specifically of their change in microenvironment upon drug binding. The three drug-protein systems investigated in this study are dihydrofolate reductase with its inhibitor trimethoprim, gyrase with novobiocin, and catechol O-methyltransferase with dinitrocatechol. It is demonstrated that UVRR spectroscopy has adequate sensitivity to be a useful means of detecting drug-protein interactions in those systems for which the electronic absorption of the aromatic amino acids changes because of hydrogen bonding and/or possible dipole-dipole and dipole-polarizability interactions with the ligand. PMID:9675211

  8. Enhanced biological denitrification in the cyclic rotating bed reactor with catechol as carbon source.

    PubMed

    Moussavi, Gholamreza; Jafari, Seyed Javad; Yaghmaeian, Kamyar

    2015-08-01

    The performance of CRBR in denitrification with catechol carbon source is presented. The influence of inlet nitrate concentration, hydraulic retention time (HRT), media filling ratio and rotational speed of media on the performance of CRBR was investigated. The bioreactor could denitrify over 95% of the nitrate at an inlet concentration up to 1000mgNO3(-)/L and a short HRT as low as 18h. The optimum media filling ratio at which the maximum denitrification was achieved in the CRBR was 30% and the contribution of media at this condition was around 36%. The optimum ratio of media filling at which the maximum denitrification was 20rpm and the contribution of rotational speed under this condition was around 17%. According to the findings, the CRBR is a high rate bioreactor and thus serves as an appropriate technology for denitrification of wastewaters containing a high concentration of nitrate and toxic organic compounds. PMID:25898088

  9. RFLP analysis of rice ( Oryza sativa L.) introgression lines

    Microsoft Academic Search

    K. K. Jena; G. Kochert; G. S. Khush

    1992-01-01

    Fifty-two introgression lines (BC2F8) from crosses between two Oryza sativa parents and five accessions of O. officinalis were analyzed for the introgression of O. officinalis chromosome segments. DNA from the parents and introgression lines was analyzed with 177 RFLP markers located at approximately 10-cM intervals over the rice chromosomes. Most probe\\/enzyme combinations detected RFLPs between the parents. Of the 174

  10. Differential effects of NADPH oxidase and xanthine oxidase inhibition on sympathetic reinnervation in postinfarct rat hearts.

    PubMed

    Lee, Tsung-Ming; Chen, Chien-Chang; Hsu, Yu-Jung

    2011-06-01

    Superoxide has been shown to play a major role in ventricular remodeling and arrhythmias after myocardial infarction. However, the source of increased myocardial superoxide production and the role of superoxide in sympathetic innervation remain to be further characterized. Male Wistar rats, after coronary artery ligation, were randomized to vehicle, allopurinol, or apocynin for 4weeks. To determine the role of peroxynitrite in sympathetic reinnervation, we also used 3-morpholinosydnonimine (a peroxynitrite generator). The postinfarction period was associated with increased oxidative stress, as measured by myocardial superoxide, nitrotyrosine, xanthine oxidase activity, NADPH oxidase activity, and dihydroethidium fluorescent staining. Measurement of myocardial norepinephrine levels revealed a significant elevation in vehicle-treated infarcted rats compared with sham. Sympathetic hyperinnervation was blunted after administration of allopurinol. Arrhythmic scores in the allopurinol-treated infarcted rats were significantly lower than those in vehicle. For similar levels of ventricular remodeling, apocynin had no beneficial effects on oxidative stress, sympathetic hyperinnervation, or arrhythmia vulnerability. Allopurinol-treated hearts had significantly decreased nerve growth factor expression, which was substantially increased after coadministration of 3-morpholinosydnonimine. These results indicate that xanthine oxidase but not NADPH oxidase largely mediates superoxide production after myocardial infarction. Xanthine oxidase inhibition ameliorates sympathetic innervation and arrhythmias possibly via inhibition of the peroxynitrite-mediated nerve growth factor pathway. PMID:21295134

  11. Xanthine oxidase biosensor for monitoring meat spoilage

    NASA Astrophysics Data System (ADS)

    Vanegas, D. C.; Gomes, C.; McLamore, E. S.

    2014-05-01

    In this study, we have designed an electrochemical biosensor for real-time detection of specific biomarkers of bacterial metabolism related to meat spoilage (hypoxanthine and xanthine). The selective biosensor was developed by assembling a `sandwich' of nanomaterials and enzymes on a platinum-iridium electrode (1.6 mm tip diameter). The materials deposited on the sensor tip include amorphous platinum nanoclusters (i.e. Pt black), reduced graphene oxide, nanoceria, and xanthine oxidase. Xanthine oxidase was encapsulated in laponite hydrogel and used for the biorecognition of hypoxanthine and xanthine (two molecules involved in the rotting of meat by spoilage microorganisms). The developed biosensor demonstrated good electrochemical performance toward xanthine with sensitivity of 2.14 +/- 1.48 ?A/mM, response time of 5.2 +/- 1.5 sec, lower detection limit of 150 +/- 39 nM, and retained at least 88% of its activity after 7 days of continuous use.

  12. Natural Compounds as Modulators of NADPH Oxidases

    PubMed Central

    2013-01-01

    Reactive oxygen species (ROS) are cellular signals generated ubiquitously by all mammalian cells, but their relative unbalance triggers also diseases through intracellular damage to DNA, RNA, proteins, and lipids. NADPH oxidases (NOX) are the only known enzyme family with the sole function to produce ROS. The NOX physiological functions concern host defence, cellular signaling, regulation of gene expression, and cell differentiation. On the other hand, increased NOX activity contributes to a wide range of pathological processes, including cardiovascular diseases, neurodegeneration, organ failure, and cancer. Therefore targeting these enzymatic ROS sources by natural compounds, without affecting the physiological redox state, may be an important tool. This review summarizes the current state of knowledge of the role of NOX enzymes in physiology and pathology and provides an overview of the currently available NADPH oxidase inhibitors derived from natural extracts such as polyphenols. PMID:24381714

  13. Cytokinin Oxidase Regulates Rice Grain Production

    Microsoft Academic Search

    Motoyuki Ashikari; Hitoshi Sakakibara; Shaoyang Lin; Toshio Yamamoto; Tomonori Takashi; Asuka Nishimura; Enrique R. Angeles; Qian Qian; Hidemi Kitano; Makoto Matsuoka

    2005-01-01

    Most agriculturally important traits are regulated by genes known as quantitative trait loci (QTLs) derived from natural allelic variations. We here show that a QTL that increases grain productivity in rice, Gn1a, is a gene for cytokinin oxidase\\/dehydrogenase (OsCKX2), an enzyme that degrades the phytohormone cytokinin. Reduced expression of OsCKX2 causes cytokinin accumulation in inflorescence meristems and increases the number

  14. Imaging Monoamine Oxidase in the Human Brain

    SciTech Connect

    Fowler, J. S.; Volkow, N. D.; Wang, G-J.; Logan, Jean

    1999-11-10

    Positron emission tomography (PET) studies mapping monoamine oxidase in the human brain have been used to measure the turnover rate for MAO B; to determine the minimum effective dose of a new MAO inhibitor drug lazabemide and to document MAO inhibition by cigarette smoke. These studies illustrate the power of PET and radiotracer chemistry to measure normal biochemical processes and to provide information on the effect of drug exposure on specific molecular targets.

  15. Defensive Roles of Polyphenol Oxidase in Plants

    Microsoft Academic Search

    C. Peter Constabel; Raymond Barbehenn

    Plant polyphenol oxidases (PPOs) are widely distributed and well-studied oxidative enzymes, and their effects on discoloration in damaged and diseased plant tissues have been known for many years. The discovery in C.A. Ryan's laboratory in the mid-1990s that tomato PPO is induced by the herbivore defense signals systemin and jasmonate, together with seminal work on PPO's possible effects on herbiv-

  16. [Cloning and sequencing of ACC oxidase gene from sugarcane].

    PubMed

    Wang, Zi-Zhang; Li, Yang-Rui; Zhang, Shu-Zhen; Lin, Jun-Fang; Guo, Li-Qiong

    2003-01-01

    The plant hormone ethylene is not only responsible for the initiation of fruit ripening, senescence and dormancy but also for regulating many other plant developmental processes, such as seed germination, root initiation, growth, floral differentiation, sex differentiation and responding to environment stresses. One of the rate-limiting steps for ethylene biosynthesizing in plant is catalyzed by 1-aminocyclopropane-1-carboxylate (ACC) oxidase. Understanding of ethylene expressive pattern in plant is an entrance to understand the roles of ethylene on plant. In this paper, two degenerate oligonucleotide primers were designed, coding for two conservative amino acid regions in ACC oxidase protein family, the sequences of the two primers were TAGAGCTCGATGC[TA]TG [CT]GA[GA]AA[AC]TGGGG and CGTCTAGAGCTTC[GA]AATCTTGGCTCCTT respectively. A PCR amplification was performed on sugarcane (Saccharum L. Hybrid cv. ROC16) DNA template, and produced a fragment of 940 bp. By using the program of BLAST on NCBI GenBank database, the sequence presented a very high match with the ACC oxidase genes from other plants, 63 searched out sequences were all ACC oxidase genes. After alignment on PCgene program, the identities of the cloned fragment with ACC oxidase genes from rice and bamboo were both reaching about 88%. So we can concluded that the cloned sequence was a member of ACC oxidase genes fragment from sugarcane. The sequence has been submitted to the GenBank database, the accession number is AF442821. According to the ACC oxidase protein family, a 'intron' of 103 bp was excluded and the sequence coded 279 amino acids, which spanned 88% of the putative whole sequence in length. Alignment and phylogenetic analysis of the amino acid sequence deduced from this fragment and the ACC oxidase sequences of other plants retrieved from GenBank were carried out by using PCgene program. The putative amino acid sequence shared a homology of 86% with the ACC oxidases of bamboo and rice, 74.6% with banana, 70% with tomato and potato and 68% with melon and carnation, which showed that the homology of sugarcane ACC oxidase with monocot was higher than with dicot. The results of phylogenetic analysis showed that ACC oxidase from sugarcane and ACC oxidases from rice clustered together firstly, and then came those from banana, ACC oxidases of dicot from potato, tomato, petunia, melon, Arabidopsis thaliana and carnation came subsequently. It indicated that sugarcane ACC oxidase had a closer phylogenetic affinities to the monocot ACC oxidase sequences than to the dicot ACC oxidases sequences. The clustering results of ACC oxidase molecules accorded with morphological classification system. PMID:12812078

  17. A mutation in the aroE gene affects pigment production, virulence, and chemotaxis in Xanthomonas oryzae pv. oryzae.

    PubMed

    Kim, Hong-Il; Noh, Tae-Hwan; Lee, Chang-Soo; Park, Young-Jin

    2015-01-01

    Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial blight (BB) in rice. To study its function, a random insertion mutation library of Xoo was constructed using the Tn5 transposon. A mutant strain with decreased virulence against the susceptible rice cultivar IR24 was isolated from the library (aroE mutant), which also had extremely low pigment production. Thermal asymmetric interlaced-polymerase chain reaction (TAIL-PCR) and sequence analysis of the mutant revealed that the transposon was inserted into the aroE gene (encoding shikimate dehydrogenase). To investigate gene expression changes in the pigment- and virulence-deficient mutant, DNA microarray analysis was performed, which showed downregulation of 20 genes involved in the chemotaxis of Xoo. Our findings reveal that mutation of the aroE gene affects virulence and pigment production, as well as expression of genes involved in Xoo chemotaxis. PMID:25213405

  18. Changes in the Plasma Membrane Distribution of Rice Phospholipase D during Resistant Interactions with Xanthomonas oryzae pv oryzae.

    PubMed

    Young, S. A.; Wang, X.; Leach, J. E.

    1996-06-01

    Phospholipase D (PLD; EC 3.1.4.4), which hydrolyzes phospholipids to generate phosphatidic acid, was examined in rice leaves undergoing susceptible or resistant interactions with Xanthomonas oryzae pv oryzae. RNA analysis of leaves undergoing resistant interactions revealed different expression patterns for PLD over 5 days relative to control plants or those undergoing susceptible interactions. By using an activity assay and immunoblot analysis, we identified three forms of PLD (1, 2, and 3). PLD 1 was observed only at 1 day after tissue infiltration. PLDs 2 and 3 were detected up to 3 days in all interactions. Immunoelectron microscopy studies revealed PLD to be associated predominantly with the plasma membrane. In cells undergoing a susceptible response, PLD was uniformly distributed along the plasma membrane at 3, 6, 12, and 24 hr after inoculation. However, within 12 hr after bacterial challenge in resistant interactions, PLD was clustered preferentially in membranes adjacent to bacterial cells. PMID:12239412

  19. Induction of human monocyte motility by lysyl oxidase.

    PubMed

    Lazarus, H M; Cruikshank, W W; Narasimhan, N; Kagan, H M; Center, D M

    1995-12-01

    Lysyl oxidase highly purified from calf aorta was found to be a potent chemotactic agent for unstimulated human peripheral blood mononuclear cells, determined in in vitro assays in Boyden chambers. A typical chemotactic bell-shaped curve was observed, with a maximal migratory response of 237% of control occurring at 10(-10) M lysyl oxidase. The chemotactic response was prevented by prior heat inactivation of the enzyme, by treatment of the enzyme with beta-aminopropionitrile or ethylenediamine, which are active site-directed inhibitors of lysyl oxidase, and by a competing, lysine-containing peptide substrate of lysyl oxidase. The chemoattractant response to lysyl oxidases was characterized by both chemokinetic and chemotactic components. These results raise the possibility that extracellular lysyl oxidase may have important roles to play in biology in addition to its established function in the crosslinking of elastin and collagen. PMID:8785587

  20. Hyperuricemia and urate nephropathy in urate oxidase-deficient mice.

    PubMed

    Wu, X; Wakamiya, M; Vaishnav, S; Geske, R; Montgomery, C; Jones, P; Bradley, A; Caskey, C T

    1994-01-18

    Urate oxidase, or uricase (EC 1.7.3.3), is a purine metabolic enzyme that catalyzes the conversion of uric acid to allantoin in most mammals except humans and certain other primates. The loss of urate oxidase in the human during primate evolution predisposes man to hyperuricemia, a metabolic disturbance that can lead to gouty arthritis and renal stones. To create a mouse model for hyperuricemia and gout, and to address the question of whether urate oxidase is essential in lower mammalian species, we have disrupted the urate oxidase gene in the mouse by homologous recombination in embryonic stem cells. Unlike the human situation, urate oxidase deficiency in mice causes pronounced hyperuricemia and urate nephropathy. More than half of the mutant mice died before 4 weeks of age, indicating that urate oxidase is essential in mice. These mutant mice may also serve as animal models for hyperuricemia and its related nephropathy in humans. PMID:8290593

  1. Action in vitro d'un herbicide (molinate) sur trois champignons parasites du riz : Sclerotium oryzae Catt.,

    E-print Network

    Paris-Sud XI, Université de

    oryzae Catt., S. hydrophilum Sacc. et Rhizoctonia oryzae Ryker et Gooch Paul BERNAUX Germaine BERTI I, Rhizoctonia oryzae). A des concentrations inférieures à Molinate, ' 0,5 g/1 de matière active, il provoque un mêmes concentrations ou à des concentrations supérieures, la reprise d'activité Rhizoctonia, des

  2. Aspergillus oryzae NRRL 35191 from coffee, a non-toxigenic endophyte with the ability to synthesize kojic acid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus oryzae was isolated as an endophyte from coffee leaves and found to produce kojic acid in culture. When inoculated in cacao seedlings (Theobroma cacao L.), A. oryzae grew endophytically and synthesize kojic acid in planta. Cacao seedlings inoculated with A. oryzae produced higher levels...

  3. Regulation of Superoxide?Producing NADPH Oxidases in Nonphagocytic Cells

    Microsoft Academic Search

    Ryu Takeya; Noriko Ueno; Hideki Sumimoto

    2006-01-01

    The membrane?integrated protein gp91phox functions as the catalytic center of the superoxide?producing phagocyte NADPH oxidase. Recent studies have identified homologs of gp91phox in nonphagocytic cells, which constitute the NADPH oxidase (Nox) family. Activation of the Nox oxidases leads to production of reactive oxygen species (ROS), thereby participating in a variety of biological events, such as host defense, hormone biosynthesis, and

  4. QTL mapping and introgression of yield-related traits from Oryza glumaepatula to cultivated rice ( Oryza sativa) using microsatellite markers.

    PubMed

    Brondani, C.; Rangel, N.; Brondani, V.; Ferreira, E.

    2002-05-01

    Rice ( Oryza sativa) cultivar development currently faces the task of overcoming yield plateaus, which is difficult due to the narrow genetic base of breeding programs. Oryza glumaepatula is a diploid wild relative of cultivated rice, native to Central and South America, and is therefore a potential source of alleles of agronomic importance to rice breeding programs. We studied 11 agronomic traits in BC(2)F(2) families of the interspecific cross Oryza sativa x O. glumaepatula. Transgressive lines which are almost isogenic to the elite recurrent O. sativa parent were identified for most of these traits. Quantitative trait locus (QTL) analysis was performed by single-point and interval mapping using a molecular map based on 157 microsatellite and STS markers. Marker regions accounting for 14.5 to 72.9% of a phenotypic variation trait were identified in 9 of the 12 rice chromosomes. Positive QTL effects from O. glumaepatula were observed in chromosomal regions associated with tillering and panicle-number traits. PMID:12582630

  5. The 1.8 Å crystal structure of catechol 1,2-dioxygenase reveals a novel hydrophobic helical zipper as a subunit linker

    Microsoft Academic Search

    Matthew W Vetting; Douglas H Ohlendorf

    2000-01-01

    Background: Intradiol dioxygenases catalyze the critical ring-cleavage step in the conversion of catecholate derivatives to citric acid cycle intermediates. Catechol 1,2-dioxygenases (1,2-CTDs) have a rudimentary design structure — a homodimer with one catalytic non-heme ferric ion per monomer, that is (?Fe3+)2. This is in contrast to the archetypical intradiol dioxygenase protocatechuate 3,4-dioxygenase (3,4-PCD), which forms more diverse oligomers, such as

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

    Microsoft Academic Search

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

    2010-01-01

    The occupied and unoccupied electronic structure of catechol adsorbed onto two single crystal surfaces, rutile TiO2(110) and wurtzite ZnO(112¯0), have been investigated using UV-photoemission and inverse photoemission spectroscopies (UPS and IPS) in an ultra-high vacuum environment. To aid in assignment of the spectral features, model metal-bound catechol structures were calculated using a DFT approach. From these measurements, the energy alignment

  7. A study on the thermostability of microencapsulated glucose oxidase.

    PubMed

    Hoshino, K; Muramatsu, N; Kondo, T

    1989-01-01

    Glucose oxidase was microencapsulated within polyurea membranes by the interfacial polymerization method and the stability to heat of the encapsulated enzyme was examined. Thermostability of microencapsulated glucose oxidase was prominent and increased with increase in the amount of glucose oxidase entrapped. This stability, however, could not be ascribed to the peculiar properties of microcapsules but was suggested to be caused by the incorporation of glucose oxidase molecules in the membranes through chemical bonding. This stability revealed that the enzyme molecules in the microcapsules could not always exist in the dissolved form but a fairly large portion of the molecules participated in the polymerization reaction and changed their enzymatic properties. PMID:2723964

  8. 21 CFR 866.2420 - Oxidase screening test for gonorrhea.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2420 Oxidase screening test for gonorrhea. (a) Identification. An...

  9. Exploring the use of Oryza species to enhance the lipid fraction of cultivated rice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the past few several years, efforts to collect rice germplasm were broadened to collect more widely from the Oryza genepool. The Oryza genus includes only 23 species, but it is remarkably diverse in-terms of its ecological adaptation. This diversity may not only be restricted to ecological charac...

  10. Resistance among U.S. wheat Triticum aestivum cultivars to the wheat pathotype of Magnaporthe oryzae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Magnaporthe oryzae is the causal agent of blast on several graminaceous plants. The M. oryzae population causing wheat blast has not been found outside South America. U.S. wheat production is at risk to this pathogen if introduced and established. Proactive testing of US wheat cultivars for their re...

  11. Instability of the Magnaporthe oryzae Avirulence gene AVR-Pita alters virulence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The avirulence gene AVR-Pita of Magnaporthe oryzae determines the efficacy of the resistance gene Pi-ta in rice. The structures of the AVR-Pita alleles in 39 US isolates of M. oryzae were analyzed using polymerase chain reaction. A series of allele-specific primers were developed from the AVR-Pita...

  12. Phylogeography of Asian wild rice, Oryza rufipogon: a genome-wide view

    E-print Network

    Purugganan, Michael D.

    Phylogeography of Asian wild rice, Oryza rufipogon: a genome-wide view PU HUANG,* JEANMAIRE MOLINA Technologies, University of Georgia, Athens, GA 30621, USA Abstract Asian wild rice (Oryza rufipogon of cultivated Asian rice (O. sativa). Studies of the geographic structure of O. rufipogon, based on chloroplast

  13. Studies on Aspergillus oryzae Mutants for the Production of Single Cell Proteins from Deoiled Rice Bran

    Microsoft Academic Search

    Rudravaram Ravinder; Linga Venkateshwar Rao; Pogaku Ravindra

    2003-01-01

    Summary Ethyl methyl sulphonate was used to induce point mutation in Aspergillus oryzae (MTCC 1846). Incubation with ethyl methyl sulphonate for 1 h resulted in 98 % killing of spores. By screening the survived colonies three hypermorphs were found (Shan1, Shan2 and Shan3). These three mutants along with the A. oryzae (MTCC 1846) were used for the production of single

  14. Light regulation of asexual development in the rice blast fungus, Magnaporthe oryzae

    Microsoft Academic Search

    Kwangwon Lee; Pratibha Singh; Wen-Chuan Chung; Joshua Ash; Tae Sung Kim; Lisa Hang

    2006-01-01

    Light is a major environmental factor that influences many biological processes. We characterized the roles of light in asexual development (including the formation of aerial hyphae and conidiophore) in Magnaporthe oryzae, which is the causal agent of rice blast disease. Our data revealed a complex nature of light regulation in the asexual developments of M. oryzae. Asexual development of M.

  15. New insights into Oryza genome evolution: high gene colinearity and differential retrotransposon amplification

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A genomic region (~247kb) from an FF genome, wild Oryza species, O. brachyantha L., was sequenced and compared to the orthologous region (~450 kb) from AA genome rice, O. sativa L. ssp japonica ¬ the first such comparison reported between cultivated Oryza and a distantly related wild species. Among ...

  16. Improved annotation through genome-scale metabolic modeling of Aspergillus oryzae

    Microsoft Academic Search

    Wanwipa Vongsangnak; Peter Olsen; Kim Hansen; Steen Krogsgaard; Jens Nielsen

    2008-01-01

    BACKGROUND: Since ancient times the filamentous fungus Aspergillus oryzae has been used in the fermentation industry for the production of fermented sauces and the production of industrial enzymes. Recently, the genome sequence of A. oryzae with 12,074 annotated genes was released but the number of hypothetical proteins accounted for more than 50% of the annotated genes. Considering the industrial importance

  17. The rice endophyte Harpophora oryzae genome reveals evolution from a pathogen to a mutualistic endophyte

    PubMed Central

    Xu, Xi-Hui; Su, Zhen-Zhu; Wang, Chen; Kubicek, Christian P.; Feng, Xiao-Xiao; Mao, Li-Juan; Wang, Jia-Ying; Chen, Chen; Lin, Fu-Cheng; Zhang, Chu-Long

    2014-01-01

    The fungus Harpophora oryzae is a close relative of the pathogen Magnaporthe oryzae and a beneficial endosymbiont of wild rice. Here, we show that H. oryzae evolved from a pathogenic ancestor. The overall genomic structures of H. and M. oryzae were found to be similar. However, during interactions with rice, the expression of 11.7% of all genes showed opposing trends in the two fungi, suggesting differences in gene regulation. Moreover, infection patterns, triggering of host defense responses, signal transduction and nutritional preferences exhibited remarkable differentiation between the two fungi. In addition, the H. oryzae genome was found to contain thousands of loci of transposon-like elements, which led to the disruption of 929 genes. Our results indicate that the gain or loss of orphan genes, DNA duplications, gene family expansions and the frequent translocation of transposon-like elements have been important factors in the evolution of this endosymbiont from a pathogenic ancestor. PMID:25048173

  18. In vitro antibacterial activity of sphaeropsidins and chemical derivatives toward Xanthomonas oryzae pv. oryzae, the causal agent of rice bacterial blight.

    PubMed

    Evidente, Antonio; Venturi, Vittorio; Masi, Marco; Degrassi, Giuliano; Cimmino, Alessio; Maddau, Lucia; Andolfi, Anna

    2011-12-27

    Sphaeropsidin A, the main phytotoxin produced by Diplodia cupressi, as well as the two natural analogues sphaeropsidins B and C and 14 derivatives obtained by chemical modifications were assayed for antibacterial activity against Xanthomonas oryzae pv. oryzae, Pseudomonas fuscovaginae, and Burkholderia glumae, the causal agents of severe bacterial rice diseases. The results showed a strong and specific activity of sphaeropsidin A against X. oryzae pv. oryzae, while no activity was observed against the other two pathogens. The results of structure-activity relationship studies showed that structural features important to impart this antibacterial activity are the presence of the C-7 carbonyl group and the hemiketalic lactone functionality. The C-13 vinyl group, the double bond of ring C, and/or the tertiary C-9 hydroxy group, as well as the pimarane arrangement of the tricylic carbon skeleton, were also important for the antibacterial activity. These findings may be useful in designing novel compounds for practical applications in agriculture. PMID:22124378

  19. Substituted catechols as complexing agents for the determination of bismuth, lead, copper and cadmium by adsorptive stripping voltammetry

    Microsoft Academic Search

    Janice Limson; Tebello Nyokong

    1997-01-01

    Copper, cadmium, lead and bismuth (> 5 ?g ml?1) are determined by adsorptive cathodic stripping voltammetry (AdCSV) on a mercury film glassy carbon electrode, using catechol, 4-methylcatechol, 4-t-butylcatechol and resorcinol as complexing ligands. Complexes of lead, copper and bismuth with resorcinol showed the largest increase in current with increase in metal concentration, whereas complexes of these metals with 4-t-butylcatechol showed

  20. Interaction of photoactive catechol with TiO 2 anatase (1 0 1) surface: A periodic density functional theory study

    Microsoft Academic Search

    Ying Xu; Wen-Kai Chen; Shu-Hong Liu; Mei-Juan Cao; Jun-Qian Li

    2007-01-01

    The plane-wave function method, based on density functional theory, has been used to calculate the adsorption, electronic band structures and optical absorption spectra of molecular and dissociative catechol adsorbed on TiO2 anatase (101) surface. The obtained electronic structures of anatase (101) surface are similar with the previous theoretical works for anatase bulk. Our calculations reveal that one type of molecular

  1. Catechol-O-Methyltransferase Gene Polymorphism Modifies the Effect of Coffee Intake on Incidence of Acute Coronary Events

    Microsoft Academic Search

    Pertti Happonen; Sari Voutilainen; Tomi-Pekka Tuomainen; Jukka T. Salonen; Thomas Zwaka

    2006-01-01

    BackgroundThe 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 FindingsIn a cohort of 773 men who were 42 to

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

    Microsoft Academic Search

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

    2004-01-01

    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\\u000a performance in healthy and schizophrenic adults. Since several of the cognitive functions typically deficient in children\\u000a with Attention Deficit Hyperactivity Disorder (ADHD) are mediated by prefrontal dopamine (DA) mechanisms, we investigated\\u000a the relationship between a functional

  3. Genotype Determining Low Catechol-O-Methyltransferase Activity as a Risk Factor for Obsessive-Compulsive Disorder

    Microsoft Academic Search

    Maria Karayiorgou; Margaret Altemus; Brandi L. Galke; David Goldman; Dennis L. Murphy; Jurg Ott; Joseph A. Gogos

    1997-01-01

    In the present study, we address the role of the gene for catechol-O-methyltransferase (COMT), a key modulator of dopaminergic and noradrenergic neurotransmission, in the genetic predisposition to obsessive-compulsive disorder (OCD). We show that a common functional allele of this gene, which results in a 3- to 4-fold reduction in enzyme activity, is significantly associated in a recessive manner with susceptibility

  4. NADPH Oxidase Promotes Neutrophil Extracellular Trap Formation in Pulmonary Aspergillosis

    PubMed Central

    Röhm, Marc; Grimm, Melissa J.; D'Auria, Anthony C.; Almyroudis, Nikolaos G.

    2014-01-01

    NADPH oxidase is a crucial enzyme in antimicrobial host defense and in regulating inflammation. Chronic granulomatous disease (CGD) is an inherited disorder of NADPH oxidase in which phagocytes are defective in generation of reactive oxidant intermediates. Aspergillus species are ubiquitous, filamentous fungi, which can cause invasive aspergillosis, a major cause of morbidity and mortality in CGD, reflecting the critical role for NADPH oxidase in antifungal host defense. Activation of NADPH oxidase in neutrophils can be coupled to the release of proteins and chromatin that comingle in neutrophil extracellular traps (NETs), which can augment extracellular antimicrobial host defense. NETosis can be driven by NADPH oxidase-dependent and -independent pathways. We therefore undertook an analysis of whether NADPH oxidase was required for NETosis in Aspergillus fumigatus pneumonia. Oropharyngeal instillation of live Aspergillus hyphae induced neutrophilic pneumonitis in both wild-type and NADPH oxidase-deficient (p47phox?/?) mice which had resolved in wild-type mice by day 5 but progressed in p47phox?/? mice. NETs, identified by immunostaining, were observed in lungs of wild-type mice but were absent in p47phox?/? mice. Using bona fide NETs and nuclear chromatin decondensation as an early NETosis marker, we found that NETosis required a functional NADPH oxidase in vivo and ex vivo. In addition, NADPH oxidase increased the proportion of apoptotic neutrophils. Together, our results show that NADPH oxidase is required for pulmonary clearance of Aspergillus hyphae and generation of NETs in vivo. We speculate that dual modulation of NETosis and apoptosis by NADPH oxidase enhances antifungal host defense and promotes resolution of inflammation upon infection clearance. PMID:24549323

  5. Rapid evaluation of biocidal activity using a transposon-encoded catechol 2,3-dioxygenase from Pseudomonas putida.

    PubMed

    Edghill, L A; Russell, A D; Day, M J; Furr, J R

    1999-07-01

    Pseudomonas putida (UWC1), containing a genetically-engineered plasmid (pQM899), that encodes for the production of catechol 2,3-dioxygenase (C230), was used as a potential means of rapidly estimating bactericidal activity of chlorhexidine diacetate (CHA), phenol, cetylpyridinium chloride (CPC) and phenylmercuric nitrate (PMN). Enzyme C230 converts catechol to 2-hydroxymuconic semialdehyde (2-HMS), which is yellow in colour, via a meta cleavage pathway. Ideal conditions for production and measurement spectrophotometrically of 2-HMS were determined. However, the correlation between this method and viable plate counts was not sufficiently accurate to enable 2-HMS production to provide a sufficiently sensitive determination of biocidal activity. An alternative method, synchronous scanning fluorimetry, in which the decrease in catechol concentration was measured under standardized conditions, provided a good dose-response histogram for all the biocides tested. Although, in comparison with plate counts, there was an underestimation of the bactericidal effects of phenol an PMN, the results of this study suggest that this method has potential in determining the bactericidal efficacy of agents such as CHA and CPC. PMID:10432591

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

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

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

    PubMed

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

    2015-06-01

    The titled compounds were examined as PPO inhibitors and antibrowning agents; their various mechanisms were investigated and discussed. All compounds reduced significantly both the browning process and PPO activity. Browning index gave strong correlation with PPO activity (r(2)?=?0.96, n?=?19) indicating that the browning process is mainly enzymatic. Ascorbic acid could reduce the formed quinone instantly to the original substrate (catechol) at high concentration (>1.5 %) while at lower concentrations acted as competitive inhibitor (KI?=?0.256?±?0.067 mM). Cysteine, at higher concentrations (?1.0 %), reacted with the resulted quinone to give a colorless products while at the low concentrations, cysteine worked as competitive inhibitor (KI?=?1.113?±?0.176 mM). Citric acid acted only as PPO non-competitive inhibitor with KI?=?2.074?±?0.363 mM. The products of PPO-catechole-cysteine reaction could be separation and identification by LC-ESI-MS. Results indicated that the product of the enzymatic oxidation of catechol, quinone, undergoes two successive nucleophilic attacks by cysteine thiol group. Cysteine was condensed with the resulted mono and dithiocatechols to form peptide side chains. PMID:26028748

  8. Gene Cluster Involved in the Biosynthesis of Griseobactin, a Catechol-Peptide Siderophore of Streptomyces sp. ATCC 700974?

    PubMed Central

    Patzer, Silke I.; Braun, Volkmar

    2010-01-01

    The main siderophores produced by streptomycetes are desferrioxamines. Here we show that Streptomyces sp. ATCC 700974 and several Streptomyces griseus strains, in addition, synthesize a hitherto unknown siderophore with a catechol-peptide structure, named griseobactin. The production is repressed by iron. We sequenced a 26-kb DNA region comprising a siderophore biosynthetic gene cluster encoding proteins similar to DhbABCEFG, which are involved in the biosynthesis of 2,3-dihydroxybenzoate (DHBA) and in the incorporation of DHBA into siderophores via a nonribosomal peptide synthetase. Adjacent to the biosynthesis genes are genes that encode proteins for the secretion, uptake, and degradation of siderophores. To correlate the gene cluster with griseobactin synthesis, the dhb genes in ATCC 700974 were disrupted. The resulting mutants no longer synthesized DHBA and griseobactin; production of both was restored by complementation with the dhb genes. Heterologous expression of the dhb genes or of the entire griseobactin biosynthesis gene cluster in the catechol-negative strain Streptomyces lividans TK23 resulted in the synthesis and secretion of DHBA or griseobactin, respectively, suggesting that these genes are sufficient for DHBA and griseobactin biosynthesis. Griseobactin was purified and characterized; its structure is consistent with a cyclic and, to a lesser extent, linear form of the trimeric ester of 2,3-dihydroxybenzoyl-arginyl-threonine complexed with aluminum under iron-limiting conditions. This is the first report identifying the gene cluster for the biosynthesis of DHBA and a catechol siderophore in Streptomyces. PMID:19915026

  9. Nox NADPH Oxidases and the Endoplasmic Reticulum

    PubMed Central

    Araujo, Thaís L.S.; Abrahão, Thalita B.

    2014-01-01

    Abstract Significance: Understanding isoform- and context-specific subcellular Nox reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase compartmentalization allows relevant functional inferences. This review addresses the interplay between Nox NADPH oxidases and the endoplasmic reticulum (ER), an increasingly evident player in redox pathophysiology given its role in redox protein folding and stress responses. Recent Advances: Catalytic/regulatory transmembrane subunits are synthesized in the ER and their processing includes folding, N-glycosylation, heme insertion, p22phox heterodimerization, as shown for phagocyte Nox2. Dual oxidase (Duox) maturation also involves the regulation by ER-resident Duoxa2. The ER is the activation site for some isoforms, typically Nox4, but potentially other isoforms. Such location influences redox/Nox-mediated calcium signaling regulation via ER targets, such as sarcoendoplasmic reticulum calcium ATPase (SERCA). Growing evidence suggests that Noxes are integral signaling elements of the unfolded protein response during ER stress, with Nox4 playing a dual prosurvival/proapoptotic role in this setting, whereas Nox2 enhances proapoptotic signaling. ER chaperones such as protein disulfide isomerase (PDI) closely interact with Noxes. PDI supports growth factor-dependent Nox1 activation and mRNA expression, as well as migration in smooth muscle cells, and PDI overexpression induces acute spontaneous Nox activation. Critical Issues: Mechanisms of PDI effects include possible support of complex formation and RhoGTPase activation. In phagocytes, PDI supports phagocytosis, Nox activation, and redox-dependent interactions with p47phox. Together, the results implicate PDI as possible Nox organizer. Future Directions: We propose that convergence between Noxes and ER may have evolutive roots given ER-related functional contexts, which paved Nox evolution, namely calcium signaling and pathogen killing. Overall, the interplay between Noxes and the ER may provide relevant insights in Nox-related (patho)physiology. Antioxid. Redox Signal. 20, 2755–2775. PMID:24386930

  10. The interaction of arsenite with xanthine oxidase.

    PubMed

    Hille, R; Stewart, R C; Fee, J A; Massey, V

    1983-04-25

    The binding of arsenite to the molybdenum center of milk xanthine oxidase is re-examined. The Kd for the arsenite complex has been determined to be 24 microM from equilibrium binding studies and this value has been confirmed by determination of the association and dissociation rate constants for the interaction of arsenite with xanthine oxidase. Formation of the complex is not prevented by prior reaction of the enzyme with thiol reagents such as 5,5'-dithiobis-(2-nitrobenzoic acid) or methyl methanethiosulfonate. Binding of arsenite to the enzyme perturbs both the oxidation-reduction potentials and the electron paramagnetic resonance signal of the molybdenum center observed after partial reduction of the enzyme with sodium dithionite. The EPR signal of the partially reduced arsenite-complexed enzyme is further modified in two different ways by the addition of xanthine or salicylate. Other purine and pteridine substrates and products for the enzyme yield EPR signals indistinguishable from that generated by xanthine, whereas aromatic aldehydes and carboxylic acids give signals similar to that observed in the presence of salicylate. It is thus clear that while arsenite prevents enzyme turnover, it does not preclude binding of substrate and product molecules. Binding of arsenite at the molybdenum center of xanthine oxidase does not disturb the oxidation-reduction potentials of the iron-sulfur centers of the enzyme, but evidence is presented to suggest that the midpoint potential of the FAD site is decreased by approximately 15 mV. A structure for the arsenite complex is proposed to provide a framework in which to interpret the EPR signals in a quantitative fashion. PMID:6300101

  11. Evidence for Biotrophic Lifestyle and Biocontrol Potential of Dark Septate Endophyte Harpophora oryzae to Rice Blast Disease

    PubMed Central

    Su, Zhen-Zhu; Mao, Li-Juan; Li, Na; Feng, Xiao-Xiao; Yuan, Zhi-Lin; Wang, Li-Wei; Lin, Fu-Cheng; Zhang, Chu-Long

    2013-01-01

    The mutualism pattern of the dark septate endophyte (DSE) Harpophora oryzae in rice roots and its biocontrol potential in rice blast disease caused by Magnaporthe oryzae were investigated. Fluorescent protein-expressing H. oryzae was used to monitor the colonization pattern. Hyphae invaded from the epidermis to the inner cortex, but not into the root stele. Fungal colonization increased with root tissue maturation, showing no colonization in the meristematic zone, slight colonization in the elongation zone, and heavy colonization in the differentiation zone. H. oryzae adopted a biotrophic lifestyle in roots accompanied by programmed cell death. Real-time PCR facilitated the accurate quantification of fungal growth and the respective plant response. The biocontrol potential of H. oryzae was visualized by inoculation with eGFP-tagged M. oryzae in rice. H. oryzae protected rice from M. oryzae root invasion by the accumulation of H2O2 and elevated antioxidative capacity. H. oryzae also induced systemic resistance against rice blast. This systemic resistance was mediated by the OsWRKY45-dependent salicylic acid (SA) signaling pathway, as indicated by the strongly upregulated expression of OsWRKY45. The colonization pattern of H. oryzae was consistent with the typical characteristics of DSEs. H. oryzae enhanced local resistance by reactive oxygen species (ROS) and high antioxidative level and induced OsWRKY45-dependent SA-mediated systemic resistance against rice blast. PMID:23637814

  12. Multicopper oxidase-1 orthologs from diverse insect species have ascorbate oxidase activity.

    PubMed

    Peng, Zeyu; Dittmer, Neal T; Lang, Minglin; Brummett, Lisa M; Braun, Caroline L; Davis, Lawrence C; Kanost, Michael R; Gorman, Maureen J

    2015-04-01

    Members of the multicopper oxidase (MCO) family of enzymes can be classified by their substrate specificity; for example, ferroxidases oxidize ferrous iron, ascorbate oxidases oxidize ascorbate, and laccases oxidize aromatic substrates such as diphenols. Our previous work on an insect multicopper oxidase, MCO1, suggested that it may function as a ferroxidase. This hypothesis was based on three lines of evidence: RNAi-mediated knock down of Drosophila melanogaster MCO1 (DmMCO1) affects iron homeostasis, DmMCO1 has ferroxidase activity, and DmMCO1 has predicted iron binding residues. In our current study, we expanded our focus to include MCO1 from Anopheles gambiae, Tribolium castaneum, and Manduca sexta. We verified that MCO1 orthologs have similar expression profiles, and that the MCO1 protein is located on the basal surface of cells where it is positioned to oxidize substrates in the hemolymph. In addition, we determined that RNAi-mediated knock down of MCO1 in A. gambiae affects iron homeostasis. To further characterize the enzymatic activity of MCO1 orthologs, we purified recombinant MCO1 from all four insect species and performed kinetic analyses using ferrous iron, ascorbate and two diphenols as substrates. We found that all of the MCO1 orthologs are much better at oxidizing ascorbate than they are at oxidizing ferrous iron or diphenols. This result is surprising because ascorbate oxidases are thought to be specific to plants and fungi. An analysis of three predicted iron binding residues in DmMCO1 revealed that they are not required for ferroxidase or laccase activity, but two of the residues (His374 and Asp380) influence oxidation of ascorbate. These two residues are conserved in MCO1 orthologs from insects and crustaceans; therefore, they are likely to be important for MCO1 function. The results of this study suggest that MCO1 orthologs function as ascorbate oxidases and influence iron homeostasis through an unknown mechanism. PMID:25701385

  13. Purification of Xanthine Dehydrogenase and Sulfite Oxidase from Chicken Liver

    Microsoft Academic Search

    Kapila Ratnam; Michael S. Brody; Russ Hille

    1996-01-01

    Xanthine dehydrogenase and sulfite oxidase from chicken liver are oxomolybdenum enzymes which catalyze the oxidation of xanthine to uric acid and sulfite to sulfate, respectively. Independent purification protocols have been previously described for both enzymes. Here we describe a procedure by which xanthine dehydrogenase and sulfite oxidase are purified simultaneously from the same batch of fresh chicken liver. Also, unlike

  14. Bilirubin oxidase bioelectrocatalytic cathodes: the impact of hydrogen peroxide.

    PubMed

    Milton, Ross D; Giroud, Fabien; Thumser, Alfred E; Minteer, Shelley D; Slade, Robert C T

    2014-01-01

    Mediator-less, direct electro-catalytic reduction of oxygen to water by bilirubin oxidase (Myrothecium sp.) was obtained on anthracene-modified, multi-walled carbon nanotubes. H2O2 was found to significantly and irreversibly affect the electro-catalytic activity of bilirubin oxidase, whereas similar electrodes comprised of laccase (Trametes versicolor) were reversibly inhibited. PMID:24185735

  15. Molecular evolution of cytochrome bd oxidases across proteobacterial genomes.

    PubMed

    Degli Esposti, Mauro; Rosas-Pérez, Tania; Servín-Garcidueñas, Luis Eduardo; Bolaños, Luis Manuel; Rosenblueth, Monica; Martínez-Romero, Esperanza

    2015-03-01

    This work is aimed to resolve the complex molecular evolution of cytochrome bd ubiquinol oxidase, a nearly ubiquitous bacterial enzyme that is involved in redox balance and bioenergetics. Previous studies have created an unclear picture of bd oxidases phylogenesis without considering the existence of diverse types of bd oxidases. Integrated approaches of genomic and protein analysis focused on proteobacteria have generated a molecular classification of diverse types of bd oxidases, which produces a new scenario for interpreting their evolution. A duplication of the original gene cluster of bd oxidase might have occurred in the ancestors of extant ?-proteobacteria of the Rhodospirillales order, such as Acidocella, from which the bd-I type of the oxidase might have diffused to other proteobacterial lineages. In contrast, the Cyanide-Insensitive Oxidase type may have differentiated into recognizable subtypes after another gene cluster duplication. These subtypes are widespread in the genomes of ?-, ?-, and ?-proteobacteria, with occasional instances of lateral gene transfer. In resolving the evolutionary pattern of proteobacterial bd oxidases, this work sheds new light on the basal taxa of ?-proteobacteria from which the ?-proteobacterial lineage probably emerged. PMID:25688108

  16. Kinetic properties of glycerophosphate oxidase isolated from dry baker's yeast

    Microsoft Academic Search

    Luciana Amade Camargo; Maria Henriques Lourenço Ribeiro; Maristela de Freitas Sanches Peres; Edwil Aparecida de Lucca Gattás

    2008-01-01

    The glycerophosphate oxidase is a flavoprotein responsible for the catalysis of the oxidation of the glycerophosphate to dihydroxyacetone phosphate, through the reduction of the oxygen to hydrogen peroxide. The glycerophosphate oxidase from baker's yeast was specific for l-?-glycerol phosphate. It was estimated by monitoring the consumption of oxygen with an oxygraph. An increase of 32% in consumption of oxygen was

  17. Methods and approaches to study plant mitochondrial alternative oxidase

    Microsoft Academic Search

    Allison E. McDonald; Stephen M. Sieger; Greg C. Vanlerberghe

    2002-01-01

    The alternative oxidase is a non-proton motive 'alternative' to electron transport through the cytochrome pathway. Despite its wasteful nature in terms of energy conservation, the path- way is likely present throughout the plant kingdom and ap- pears to be expressed in most plant tissues. A small alterna- tive oxidase gene family exists, the members of which are differentially expressed in

  18. Polyphenol Oxidase: Characteristics and Mechanisms of Browning Control

    Microsoft Academic Search

    Christiane Queiroz; Maria Lúcia Mendes Lopes; Eliane Fialho; Vera Lúcia Valente-Mesquita

    2008-01-01

    Polyphenol oxidase, a copper-containing metalloprotein, catalyzes the oxidation of phenolic compounds to quinones, which produce brown pigments in wounded tissues. This enzymatic mechanism causes post harvest losses and mainly affects tropical fruits. In this article, some characteristics of polyphenol oxidase from different plants are reviewed and information about conventional and alternative methods to inactivate this enzyme is presented. Characterization of

  19. A prokaryotic alternative oxidase present in the bacterium Novosphingobium aromaticivorans

    Microsoft Academic Search

    Pål Stenmark; Pär Nordlund

    2003-01-01

    The alternative oxidase (AOX) is a terminal oxidase present in the respiratory chain of all plants as well as some yeasts and trypanosomes, but has not previously been found in a prokaryote. We have identified an AOX homologue in Novosphingobium aromaticivorans, the first AOX found in a prokaryote. We have cloned the gene for the N. aromaticivorans AOX and showed

  20. A study on heat-resistance of microencapsulated glucose oxidase.

    PubMed

    Komori, T; Muramatsu, N; Kondo, T

    1986-01-01

    Polyurea microcapsules containing glucose oxidase were prepared and their thermodurability was examined. Microencapsulated glucose oxidase was found to be more stable to heat than the enzyme in free solution. This stability was enhanced with an increase in the amount of enzyme entrapped in the microcapsules. PMID:3508188

  1. Polymorphic minisatellites in the mitochondrial DNAs of Oryza and Brassica.

    PubMed

    Honma, Yujiro; Yoshida, Yu; Terachi, Toru; Toriyama, Kinya; Mikami, Tetsuo; Kubo, Tomohiko

    2011-08-01

    Polymorphic analyses of angiosperm mitochondrial DNA are rare in comparison with chloroplast DNA, because few target sequences in angiosperm mitochondrial DNA are known. Minisatellites, a tandem array of repeated sequences with a repeat unit of 10 to ~100 bp, are popular target sequences of animal mitochondria, but Beta vulgaris is the only known angiosperm species for which such an analysis has been conducted. From this lack of information, it was uncertain as to whether polymorphic minisatellites existed in other angiosperm species. Ten plant mitochondrial DNAs were found to contain minisatellite-like repeated sequences, most of which were located in intergenic regions but a few occurred in gene coding and intronic regions. Oryza and Brassica accessions were selected as models for the investigation of minisatellite polymorphism because substantial systematic information existed. PCR analysis of 42 Oryza accessions revealed length polymorphisms in four of the five minisatellites. The mitochondrial haplotypes of the 16 Oryza accessions with chromosomal complement (genome) types of CC, BBCC and CCDD were identical but were clearly distinguished from BB-genome accessions, a result consistent with the notion that the cytoplasmic donor parent of the amphidiploid species might be the CC-genome species. Twenty-nine accessions of six major cultivated species of Brassica were classified into five mitochondrial haplotypes based on two polymorphic minisatellites out of six loci. The haplotypes of Brassica juncea and Brassica carinata accessions were identical to Brassica rapa and Brassica nigra accessions, respectively. The haplotypes of Brassica napus accessions were heterogeneous and unique, results that were consistent with previous studies. PMID:21562713

  2. Identification of the active-site peptide of 2,3-dihydroxybenzoic acid decarboxylase from Aspergillus oryzae.

    PubMed

    Santha, R; Rao, N A; Vaidyanathan, C S

    1996-04-16

    The non-oxidative decarboxylation of aromatic acids is a poorly understood reaction. The transformation of 2,3-dihydroxybenzoic acid to catechol in the fungal metabolism of indole is a prototype of such a reaction. 2,3-Dihydroxybenzoic acid decarboxylase (EC 4.1.1.46) which catalyzes this reaction was purified to homogeneity from anthranilate induced cultures of Aspergillus oryzae using affinity chromatography. The enzyme did not require cofactors like NAD+, PLP, TPP or metal ions for its activity. There was no spectral evidence for the presence of enzyme bound cofactors. The preparation, which was adjudged homogeneous by the criteria of SDS-PAGE, sedimentation analysis and N-terminal analysis, was characterized for its physicochemical and kinetic parameters. The enzyme was inactivated by group-specific modifiers like diethyl pyrocarbonate (DEPC) and N-ethylmaleimide (NEM). The kinetics of inactivation by DEPC suggested the presence of a single class of essential histidine residues, the second order rate constant of inactivation for which was 12.5 M-1 min-1. A single class of cysteine residues was modified by NEM with a second order rate constant of 33 M-1 min-1. Substrate analogues protected the enzyme against inactivation by both DEPC and NEM, suggesting the location of the essential histidine and cysteine to be at the active site of the enzyme. The incorporation of radiolabelled NEM in a differential labelling experiment was 0.73 mol per mol subunit confirming the presence of a single essential cysteine per active-site. Differentially labelled enzyme was enzymatically cleaved and the peptide bearing the label was purified and sequenced. The active-site peptide LLGLAETCK and the N-terminal sequence MLGKIALEEAFALPRFEEKT did not bear any similarity to sequences reported in the Swiss-Prot Protein Sequence Databank, a reflection probably of the unique primary structure of this novel enzyme. The sequences reported in this study will appear in the Swiss-Prot Protein Sequence Databank under the accession number P80402. PMID:8620029

  3. Indoloditerpenes from an algicolous isolate of Aspergillus oryzae.

    PubMed

    Qiao, Ming-Feng; Ji, Nai-Yun; Liu, Xiang-Hong; Li, Ke; Zhu, Qing-Mei; Xue, Qin-Zhao

    2010-10-01

    Two new indoloditerpene derivatives asporyzin A (1) and asporyzin B (2), one new indoloditerpene asporyzin C (3), and three known related indoloditerpenes JBIR-03 (4), emindole SB (5), and emeniveol (6) were isolated from an endophytic fungus Aspergillus oryzae, isolated from the marine red alga Heterosiphonia japonica. Their structures were unambiguously established by spectroscopic techniques. In addition, all the isolates were evaluated preliminarily for insecticidal and antimicrobial activities in order to probe into their chemical defensive function. Compound 4 was more active against brine shrimp than the others, and 3 possessed potent activity against Escherichia coli. PMID:20797856

  4. Bioremediation of Dyes in Textile Effluents by Aspergillus oryzae

    Microsoft Academic Search

    Carlos Renato Corso; Ana Carolina Maganha de Almeida

    2009-01-01

    In this study Aspergillus oryzae was utilized to remove azo dyes from aqueous solution. Physically induced in its paramorphogenic form to produce standardized\\u000a mycelial pellets, the non-autoclaved and autoclaved hyphae biomass was applied to biosorb the reactive dyes Procion Red HE7B\\u000a (PR-HE7B) and Procion Violet H3R (PV-H3R) at different pH values (2.50, 4.50, and 6.50). The best pH for biosorption

  5. Genotypic Variation in Cytokinin Oxidase from Phaseolus Callus Cultures 1

    PubMed Central

    Kaminek, Miroslav; Armstrong, Donald J.

    1990-01-01

    Genotypic variation in cytokinin oxidase has been detected in enzyme preparations from Phaseolus vulgaris L. cv Great Northern and Phaseolus lunatus L. cv Kingston callus cultures. Although cytokinin oxidase preparations from Great Northern and Kingston callus tissues appear to have very similar substrate specificities, the cytokinin oxidase activities from the two callus tissues were found to differ in a number of other properties. The cytokinin oxidase from P. vulgaris cv Great Northern callus tissue exhibited a pH optimum of 6.5 (bisTris) and had a strong affinity for the lectin concanavalin A. The cytokinin oxidase from P. lunatus cv Kingston callus tissue exhibited a pH optimum of 8.4 (Taps) and did not bind to concanavalin A. The two enzymes also differed in position of elution when chromatographed on DEAE-cellulose. Both cytokinin oxidase activities exhibited enhanced activity and lower pH optima in the presence of copper-imidazole complexes, but the optimum copper-imidazole ratio and the magnitude of enhancement differed for the two activities. In both callus tissues, transient increases in the supply of exogenous cytokinins induced increases in cytokinin oxidase activity. The differences in pH optima and in glycosylation (as evidenced by the observed difference in lectin affinity) of the cytokinin oxidases from Great Northern and Kingston callus tissues suggest that the compartmentation of cytokinin oxidase may differ in the two callus tissues. The possibility that enzyme compartmentation and isozyme variation in cytokinin oxidase may play a role in the regulation of cytokinin degradation in plant tissues is discussed in relation to known differences in the rates of cytokinin degradation in Great Northern and Kingston callus tissues. Images Figure 6 PMID:16667652

  6. Effects of cholesterol oxidase on cultured vascular smooth muscle cells.

    PubMed

    Liu, K Z; Maddaford, T G; Ramjiawan, B; Kutryk, M J; Pierce, G N

    1991-11-13

    Cholesterol oxidase (3 beta-hydroxy-steroid oxidase) catalyzes the oxidation of cholesterol to 4-cholesten-3 one and other oxidized cholesterol derivatives. The purpose of the present study was to investigate its effects on cultured vascular smooth muscle cells. Cultured rabbit aortic smooth muscle cells were morphologically altered after exposure to cholesterol oxidase in the presence of culture medium containing 10% fetal calf serum. If fetal calf serum was absent, cells were unaffected by the treatment. The extent of morphological change of the smooth muscle cells was dependent upon the time of exposure to the enzyme and the concentration of cholesterol oxidase employed. After moderate treatment with cholesterol oxidase, cells excluded trypan blue. Further, a specific mitochondrial marker DASPMI (dimethyl aminostyryl-methyl-pyridiniumiodine) which was used as a fluorescent index of cell viability, revealed that cell viability was unchanged after moderate cholesterol oxidase treatment. Nile red, a hydrophobic probe which selectively stains intracellular lipid droplets, was applied to detect the cellular lipid content after treatment with cholesterol oxidase. Cellular nile red fluorescence intensity increased linearly with the time and concentration of cholesterol oxidase treatment. These results demonstrate that cholesterol oxidase alters lipid deposition in the cell and changes cell morphology. The primary site of action of cholesterol oxidase appears to be independent of the cell membrane itself and instead is dependent upon the lipid content in the surrounding culture media. These changes occur prior to the cytotoxic effects of extensive oxidation. Because oxidized cholesterol may play an important role in the pathogenesis of atherosclerosis, our results have implications for intracellular accumulation of lipids in smooth muscle cells during the atherosclerotic lesion. PMID:1770944

  7. Xanthine oxidase inhibitors from Garcinia esculenta twigs.

    PubMed

    Zhu, Lun-Lun; Fu, Wen-Wei; Watanabe, Shimpei; Shao, Yi-Nuo; Tan, Hong-Sheng; Zhang, Hong; Tan, Chang-Heng; Xiu, Yan-Feng; Norimoto, Hisayoshi; Xu, Hong-Xi

    2014-12-01

    The EtOAc-soluble portion of the 80?% (v/v) EtOH extract from the twigs of Garcinia esculenta exhibited strong xanthine oxidase inhibition in vitro. Bioassay-guided purification led to the isolation of 1,3,6,7-tetrahydroxyxanthone (3) and griffipavixanthone (8) as the main xanthine oxidase inhibitors, along with six additional compounds (1, 2, 4-7), including two new compounds (1 and 2). This enzyme inhibition was dose dependent with an IC50 value of approximately 1.2?µM for 3 and 6.3?µM for 8. The inhibitory activity of 3 was stronger than the control allopurinol (IC50 value: 5.3?µM). To our knowledge, compound 8 is the first bixanthone that demonstrated potent XO inhibitory activity in vitro. The structures of the new compounds were established by spectroscopic analysis, and the optical properties and absolute stereochemistry of racemic (±) esculentin A (2) were further determined by the calculation of the DP4 probability and analysis of its MTPA ester derivatives. PMID:25340468

  8. Interheme electron tunneling in cytochrome c oxidase

    PubMed Central

    Kaila, Ville R. I.; Johansson, Mikael P.; Sundholm, Dage; Wikström, Mårten

    2010-01-01

    Cytochrome c oxidase (CcO) is the terminal enzyme of the respiratory chain that catalyzes respiratory reduction of dioxygen (O2) to water in all eukaryotes and many aerobic bacteria. CcO, and its homologs among the heme-copper oxidases, has an active site composed of an oxygen-binding heme and a copper center in the vicinity, plus another heme group that donates electrons to this site. In most oxidoreduction enzymes, electron transfer (eT) takes place by quantum-mechanical electron tunneling. Here we show by independent molecular dynamics and quantum-chemical methods that the heme-heme eT in CcO differs from the majority of cases in having an exceptionally low reorganization energy. We show that the rate of interheme eT in CcO may nevertheless be predicted by the Moser-Dutton equation if reinterpreted as the average of the eT rates between all individual atoms of the donor and acceptor weighed by the respective packing densities between them. We argue that this modification may be necessary at short donor/acceptor distances comparable to the donor/acceptor radii. PMID:21106766

  9. Association between catechol-O-methyltransferase Val¹??Met polymorphism and configural mode of face processing.

    PubMed

    Doi, Hirokazu; Nishitani, Shota; Shinohara, Kazuyuki

    2015-01-23

    Human visual system heavily relies on the spatial configuration among facial parts in discriminating faces. There are individual differences in the ability of configural face processing, which are supposed to be partly attributable to genetic predispositions. However, few studies have identified a specific gene linked to configural face processing ability. The present study investigated an association between configural mode of face processing and a single-nucleotide polymorphism in codon 158 of catechol-O-methyltransferase gene (COMT Val(158)Met polymorphism) using part-spacing paradigm. The results have revealed superior sensitivity to the changes in facial configuration in participants with Met/Met genotype of COMT Val(158)Met polymorphism compared to the other genotypes. This effect was virtually eliminated when the faces were presented upside-down. There was no group-difference in the ability to detect the change in morphological features of individual facial parts. These results indicate that COMT Val(158)Met polymorphism partly explains the individual differences in the ability of configural face processing. PMID:25481766

  10. Polyoxometalate/laccase-mediated oxidative polymerization of catechol for textile dyeing.

    PubMed

    Kim, Suyeon; Silva, Carla; Evtuguin, Dmitry V; Gamelas, José A F; Cavaco-Paulo, Artur

    2011-02-01

    The synergistic effect between polyoxometalates (POMs), namely K(5)[SiW(11)V(V)O(40)]·11H(2)O and H(5)[PMo(10)V(V) (2)O(40)]·13H(2)O and laccase from ascomycete Myceliophthora thermophila has been employed for the first time in oxidative polymerization of catechol. Such a laccase-mediator system allowed the formation of a relatively high molecular weight polycatechol as confirmed by size exclusion chromatography and electrospray ionization mass spectrometry (ESI-MS) (3990 Da when using K(5)[SiW(11)V(V)O(40)]·11H(2)O and 3600 Da with H(5)[PMo(10)V(V) (2)O(40)]·13H(2)O). The synthesized polymers were applied as dyes for the dyeing of flax fabrics. The color intensity of flax fabrics colored with polymer solutions was evaluated by diffuse reflectance spectrophotometry via k/s measurements (+10% of fixation ratio). A new synthetic process allowed a dyeing polymer, provided upon flax coloration, better color fixation and color resistance when compared to that obtained by conventional synthesis with laccase solely or with addition of organic mediator (1-hydroxybenzotriazole). PMID:20953600

  11. TRAUMATIC BRAIN INJURY STIMULATES HIPPOCAMPAL CATECHOL-O-METHYL TRANSFERASE EXPRESSION IN MICROGLIA

    PubMed Central

    Redell, John B.; Dash, Pramod K.

    2007-01-01

    Outcome following traumatic brain injury (TBI) is in large part determined by the combined action of multiple processes. In order to better understand the response of the central nervous system to injury, we utilized an antibody array to simultaneously screen 507 proteins for altered expression in the injured hippocampus, a structure critical for memory formation. Array analysis indicated 41 candidate proteins have altered expression levels 24 hours after TBI. Of particular interest was catechol-O-methyl transferase (COMT), an enzyme involved in metabolizing catecholamines released following neuronal activity. Altered catecholamine signaling has been observed after brain injury, and may contribute to the cognitive dysfunctions and behavioral deficits often experienced after TBI. Our data shows that COMT expression in the injured ipsilateral hippocampus was elevated for at least 14 days after controlled cortical impact injury. We found strong co-localization of COMT immunoreactivity with the microglia marker Iba1 near the injury site. Since dopamine transporter expression has been reported to be down-regulated after brain injury, COMT-mediated catecholamine metabolism may play a more prominent role in terminating catecholamine signaling in injured areas. PMID:17240060

  12. Formation of cyclopentadienyl radical from the gas-phase pyrolysis of hydroquinone, catechol, and phenol.

    PubMed

    Khachatryan, Lavrent; Adounkpe, Julien; Maskos, Zofia; Dellinger, Barry

    2006-08-15

    The formation of radicals from the gas-phase pyrolysis of hydroquinone, catechol, and phenol over a temperature range of 400-750 degrees C was studied using the technique of low-temperature matrix isolation electron paramagnetic resonance (LTMI EPR). Cooling the reactor effluent from pyrolysis in a nitrogen carrier gas to 77 K produces a cryogenic matrix that exhibits poorly resolved EPR spectra. However, using carbon dioxide as a carrier gas formed a matrix that, upon annealing by slowly raising the matrix temperature followed by rapid recooling to 77 K, yielded more resolved, identifiable spectra. Annealed spectra of all three samples resulted in the generation of EPR spectra above 700 degrees C with 6 lines, hyperfine splitting constant approximately 6.0 G, and peak to peak width approximately 3 G that was readily assignable, based on comparison to the literature and theoretical calculations, as that of cyclopentadienyl radical. Pyrolysis at temperatures below 700 degrees C generated a carbon dioxide matrix isolation spectrum with a high g-value (>2.0040) that is attributed to oxygen-containing radicals such as semiquinone or phenoxyl. Conclusive identification of anticipated semiquinone, phenoxyl, and hydroxycyclopentadienyl radicals was complicated by the ability of these radicals to exist in carbon-centered and oxygen-centered resonance structures that can give different EPR spectra. PMID:16955909

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

    PubMed Central

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

    2014-01-01

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

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

    PubMed Central

    Correia da Costa, José M.; Vale, Nuno; Gouveia, Maria J.; Botelho, Mónica C.; Sripa, Banchob; Santos, Lúcio L.; Santos, Júlio H.; Rinaldi, Gabriel; Brindley, Paul J.

    2014-01-01

    Infection with helminth parasites remains a persistent public health problem in developing countries. Three of these pathogens, the liver flukes Clonorchis sinensis, Opisthorchis viverrini and the blood fluke Schistosoma haematobium, are of particular concern due to their classification as Group 1 carcinogens: infection with these worms is carcinogenic. Using liquid chromatography-mass spectrometry (LC-MS/MS) approaches, we identified steroid hormone like (e.g., oxysterol-like, catechol estrogen quinone-like, etc.) metabolites and related DNA-adducts, apparently of parasite origin, in developmental stages including eggs of S. haematobium, in urine of people with urogenital schistosomiasis, and in the adult stage of O. viverrini. Since these kinds of sterol derivatives are metabolized to active quinones that can modify DNA, which in other contexts can lead to breast and other cancers, helminth parasite associated sterols might induce tumor-like phenotypes in the target cells susceptible to helminth parasite associated cancers, i.e., urothelial cells of the bladder in the case of urogenital schistosomiasis and the bile duct epithelia or cholangiocytes, in the case of O. viverrini and C. sinensis. Indeed we postulate that helminth induced cancers originate from parasite estrogen-host epithelial/urothelial cell chromosomal DNA adducts, and here we review recent findings that support this conjecture. PMID:25566326

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

    PubMed

    Correia da Costa, José M; Vale, Nuno; Gouveia, Maria J; Botelho, Mónica C; Sripa, Banchob; Santos, Lúcio L; Santos, Júlio H; Rinaldi, Gabriel; Brindley, Paul J

    2014-01-01

    Infection with helminth parasites remains a persistent public health problem in developing countries. Three of these pathogens, the liver flukes Clonorchis sinensis, Opisthorchis viverrini and the blood fluke Schistosoma haematobium, are of particular concern due to their classification as Group 1 carcinogens: infection with these worms is carcinogenic. Using liquid chromatography-mass spectrometry (LC-MS/MS) approaches, we identified steroid hormone like (e.g., oxysterol-like, catechol estrogen quinone-like, etc.) metabolites and related DNA-adducts, apparently of parasite origin, in developmental stages including eggs of S. haematobium, in urine of people with urogenital schistosomiasis, and in the adult stage of O. viverrini. Since these kinds of sterol derivatives are metabolized to active quinones that can modify DNA, which in other contexts can lead to breast and other cancers, helminth parasite associated sterols might induce tumor-like phenotypes in the target cells susceptible to helminth parasite associated cancers, i.e., urothelial cells of the bladder in the case of urogenital schistosomiasis and the bile duct epithelia or cholangiocytes, in the case of O. viverrini and C. sinensis. Indeed we postulate that helminth induced cancers originate from parasite estrogen-host epithelial/urothelial cell chromosomal DNA adducts, and here we review recent findings that support this conjecture. PMID:25566326

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

    PubMed

    Wendt, Laura; Albring, Antje; Benson, Sven; Engler, Harald; Engler, Andrea; Hinney, Anke; Rief, Winfried; Witzke, Oliver; Schedlowski, Manfred

    2014-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

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

  18. Catechol--an oviposition stimulant for cigarette beetle in roasted coffee beans.

    PubMed

    Nagasawa, Atsuhiko; Kamada, Yuji; Kosaka, Yuji; Arakida, Naohiro; Hori, Masatoshi

    2014-05-01

    The cigarette beetle, Lasioderma serricorne, is a serious global pest that preys on stored food products. Larvae of the beetle cannot grow on roasted coffee beans or dried black or green tea leaves, although they oviposit on such products. We investigated oviposition by the beetles on MeOH extracts of the above products. The number of eggs laid increased with an increase in dose of each extract, indicating that chemical factors stimulate oviposition by the beetles. This was especially true for \\ coffee bean extracts, which elicited high numbers of eggs even at a low dose (0.1 g bean equivalent/ml) compared to other extracts. Coffee beans were extracted in hexane, chloroform, 1-butanol, MeOH, and 20% MeOH in water. The number of eggs laid was higher on filter papers treated with chloroform, 1-butanol, MeOH, and 20% MeOH in water extracts than on control (solvent alone) papers. The chloroform extract was fractionated by silica-gel column chromatography. Nine compounds were identified by gas chromatography/mass spectrometry from an active fraction. Of these compounds, only a significant ovipositional response to catechol was observed. PMID:24752858

  19. Induced systemic resistance responses in perennial ryegrass against Magnaporthe oryzae elicited by semi-purified surfactin lipopeptides and live cells of Bacillus amyloliquefaciens.

    PubMed

    Rahman, Alamgir; Uddin, Wakar; Wenner, Nancy G

    2015-08-01

    The suppressive ability of several strains of cyclic lipopeptide-producing Bacillus rhizobacteria to grey leaf spot disease caused by Magnaporthe oryzae has been documented previously; however, the underlying mechanism(s) involved in the induced systemic resistance (ISR) activity in perennial ryegrass (Lolium perenne?L.) remains unknown. Root-drench application of solid-phase extraction (SPE)-enriched surfactin and live cells of mutant Bacillus amyloliquefaciens strain FZB42-AK3 (produces surfactin, but not bacillomycin D and fengycin) significantly reduced disease incidence and severity on perennial ryegrass. The application of the treatments revealed a pronounced multilayered ISR defence response activation via timely and enhanced accumulation of hydrogen peroxide (H2 O2 ), elevated cell wall/apoplastic peroxidase activity, and deposition of callose and phenolic/polyphenolic compounds underneath the fungal appressoria in naïve leaves, which was significantly more intense in treated plants than in mock-treated controls. Moreover, a hypersensitive response (HR)-type reaction and enhanced expression of LpPrx (Prx, peroxidase), LpOXO4 (OXO, oxalate oxidase), LpPAL (PAL, phenylalanine ammonia lyase), LpLOXa (LOX, lipoxygenase), LpTHb (putative defensin) and LpDEFa (DEFa, putative defensin) in perennial ryegrass were associated with SPE-enriched surfactin and live AK3 cell treatments, acting as a second layer of defence when pre-invasive defence responses failed. The results indicate that ISR activity following surfactin perception may sensitize H2 O2 -mediated defence responses, thereby providing perennial ryegrass with enhanced protection against M.?oryzae. PMID:25285593

  20. In-depth insight into in vivo apoplastic secretome of rice-Magnaporthe oryzae interaction.

    PubMed

    Kim, Sang Gon; Wang, Yiming; Lee, Kyung Hee; Park, Zee-Yong; Park, Jongsun; Wu, Jingni; Kwon, Soon Jae; Lee, Yong-Hwan; Agrawal, Ganesh Kumar; Rakwal, Randeep; Kim, Sun Tae; Kang, Kyu Young

    2013-01-14

    The in vivo apoplastic fluid secretome of rice-blast fungus interaction remains largely uncharacterized. Here, we report a proteomics investigation of in vivo secreted proteins of rice leaves infected with incompatible (KJ401) and compatible (KJ301) races of Magnaporthe oryzae (M. oryzae) using 2-DGE and MudPIT coupled with MALDI-TOF-MS and/or nESI-LC-MS/MS analyses. Prepared fractions of secretory proteins were essentially free from cytoplasmic contamination. Two-DGE and MudPIT identified 732 secretory proteins, where 291 (40%) and 441 (60%) proteins were derived from rice and M. oryzae, respectively. Of these, 39.2% (rice) and 38.9% (M. oryzae) of proteins were predicted by SignalP as retaining signal peptides. Among these, rice secreted more proteins related to stress response, ROS and energy metabolism, whereas, M. oryzae secreted more proteins involved in metabolism and cell wall hydrolyses. Semi-quantitative RT-PCR revealed their differential expression under compatible/incompatible interactions. In vivo expression of M. oryzae glycosyl hydrolase (GH) protein family members using particle bombardment driven transient expression system showed that four GH genes could act as effectors within host apoplast possibly via interaction with host membrane bound receptor. The established in vivo secretome serves as a valuable resource toward secretome analysis of rice-M. oryzae interaction. PMID:23159799

  1. Toward understanding of rice innate immunity against Magnaporthe oryzae.

    PubMed

    Azizi, P; Rafii, M Y; Abdullah, S N A; Nejat, N; Maziah, M; Hanafi, M M; Latif, M A; Sahebi, M

    2014-09-01

    Abstract The blast fungus, Magnaporthe oryzae, causes serious disease on a wide variety of grasses including rice, wheat and barley. The recognition of pathogens is an amazing ability of plants including strategies for displacing virulence effectors through the adaption of both conserved and variable pathogen elicitors. The pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) and effector-triggered immunity (ETI) were reported as two main innate immune responses in plants, where PTI gives basal resistance and ETI confers durable resistance. The PTI consists of extracellular surface receptors that are able to recognize PAMPs. PAMPs detect microbial features such as fungal chitin that complete a vital function during the organism's life. In contrast, ETI is mediated by intracellular receptor molecules containing nucleotide-binding (NB) and leucine rich repeat (LRR) domains that specifically recognize effector proteins produced by the pathogen. To enhance crop resistance, understanding the host resistance mechanisms against pathogen infection strategies and having a deeper knowledge of innate immunity system are essential. This review summarizes the recent advances on the molecular mechanism of innate immunity systems of rice against M. oryzae. The discussion will be centered on the latest success reported in plant-pathogen interactions and integrated defense responses in rice. PMID:25198435

  2. Enhanced acid tolerance of Rhizopus oryzae during fumaric acid production.

    PubMed

    Liu, Ying; Lv, Chunwei; Xu, Qing; Li, Shuang; Huang, He; Ouyang, Pingkai

    2015-02-01

    Ensuring a suitable pH in the culture broth is a major problem in microorganism-assisted industrial fermentation of organic acids. To address this issue, we investigated the physiological changes in Rhizopus oryzae at different extracellular pH levels and attempted to solve the issue of cell shortage under low pH conditions. We compared various parameters, such as membrane fatty acids' composition, intracellular pH, and adenosine triphosphate (ATP) concentration. It was found that the shortage of intracellular ATP might be the main reason for the low rate of fumaric acid production by R. oryzae under low pH conditions. When 1 g/l citrate was added to the culture medium at pH 3.0, the intracellular ATP concentration increased from 0.4 to 0.7 µmol/mg, and the fumaric acid titer was enhanced by 63% compared with the control (pH 3.0 without citrate addition). The final fumaric acid concentration at pH 3.0 reached 21.9 g/l after 96 h of fermentation. This strategy is simple and feasible for industrial fumaric acid production under low pH conditions. PMID:25190324

  3. Interaction of bovine serum amine oxidase with the polyamine oxidase inactivator MDL 72527.

    PubMed

    Agostinelli, Enzo; Palmigiani, Paola; Vedova, Laura Dalla; Tempera, Giampiero; Belli, Francesca; Seiler, Nikolaus

    2006-02-17

    MDL 72527 was considered a selective inhibitor of FAD-dependent polyamine oxidases. In the present communication, we demonstrate that MDL 72527 inactivates bovine serum amine oxidase, a copper-containing, TPQ-enzyme, time-dependently at 25 degrees C. In striking contrast, the enzyme remained active after incubation with excessive MDL 72527 at 37 degrees C, even after 70 h of incubation. Inactivation of BSAO with MDL 72527 at 25 degrees C did not involve the cofactor, as was shown by spectroscopy and by reaction with phenylhydrazine. Docking of MDL 72527 is difficult, owing to its size and two lipophilic moieties, and it has been shown that minor changes in reaction rate of substrates cause major changes in K(m) and k(cat)/K(m). We hypothesise that subtle conformational changes between 25 and 37 degrees C impair MDL 72527 from productive binding and prevent the nucleophilic group from reacting with the double bond system. PMID:16380084

  4. Evaluation of oxalate decarboxylase and oxalate oxidase for industrial applications.

    PubMed

    Cassland, Pierre; Sjöde, Anders; Winestrand, Sandra; Jönsson, Leif J; Nilvebrant, Nils-Olof

    2010-05-01

    Increased recirculation of process water has given rise to problems with formation of calcium oxalate incrusts (scaling) in the pulp and paper industry and in forest biorefineries. The potential in using oxalate decarboxylase from Aspergillus niger for oxalic acid removal in industrial bleaching plant filtrates containing oxalic acid was examined and compared with barley oxalate oxidase. Ten different filtrates from chemical pulping were selected for the evaluation. Oxalate decarboxylase degraded oxalic acid faster than oxalate oxidase in eight of the filtrates, while oxalate oxidase performed better in one filtrate. One of the filtrates inhibited both enzymes. The potential inhibitory effect of selected compounds on the enzymatic activity was tested. Oxalate decarboxylase was more sensitive than oxalate oxidase to hydrogen peroxide. Oxalate decarboxylase was not as sensitive to chlorate and chlorite as oxalate oxidase. Up to 4 mM chlorate ions, the highest concentration tested, had no inhibitory effect on oxalate decarboxylase. Analysis of the filtrates suggests that high concentrations of chlorate present in some of the filtrates were responsible for the higher sensitivity of oxalate oxidase in these filtrates. Oxalate decarboxylase was thus a better choice than oxalate oxidase for treatment of filtrates from chlorine dioxide bleaching. PMID:19763895

  5. Two o-type oxidases in Methylobacillus flagellatum KT.

    PubMed

    Muntyan, M S; Bloch, D A; Dinarieva, T Y; Drachev, L A; Netrusov, A I

    1994-10-14

    Two oxidases of the o-type in membranes of the methanol-grown obligate methylotroph Methylobacillus flagellatum KT were distinguished. For this purpose the kinetic analysis of the laser flash-induced optical absorbance changes of CO-oxidase complexes under reducing conditions was used. The ratio of these oxidases in membranes greatly depended on the phases of bacterial growth. One of the oxidases appeared to belong to the Escherichia coli o-type oxidase family being more sensitive to KCN (Ki = 1 microM). It showed monophasic CO recombination kinetics with tau 25-30 ms and was expressed in the early exponential phase of growth. The other oxidase seemed to be similar to the Bacillus sp. FTU o-type oxidase being less sensitive to KCN (Ki = 6 microM), having three-phasic CO reassociation kinetics with tau 35-70 microseconds, 0.25-0.5 ms and 2-4 ms and dominating in the stationary growth phase. Pyridine haemochrome spectra showed haems A and D to be absent from the bacterial membranes. PMID:7945389

  6. Quantitation of immunoadsorbed flavoprotein oxidases by luminol-mediated chemiluminescence.

    PubMed

    Hinkkanen, A; Maly, F E; Decker, K

    1983-04-01

    The detection of the flavoenzymes 6-hydroxy-L-nicotine oxidase and 6-hydroxy-D-nicotine oxidase at the sub-femtomol level was achieved by coupling the reaction of the immunoadsorbed proteins to the peroxidase-catalysed oxidation of luminol. The H2O2-producing oxidases retained their full activity when bound to the respective immobilized antibodies. This fact allowed the concentration of the enzymes from very dilute solutions and the quantitative assay of their activities in the microU range. Due to strict stereoselectivity and the absence of immunological cross-reactivity, the two flavoproteins could be determined in the same solution. This method was used to measure the 6-hydroxy-D-nicotine oxidase and 6-hydroxy-L-nicotine oxidase activities in Escherichia coli RR1 and different Arthrobacter strains cultured under non-inducing conditions. The same activity ratio of 6-hydroxy-L-nicotine oxidase/6-hydroxy-D-nicotine oxidase as in D L-nicotine-induced cells of A. oxidans was observed in non-induced wild type and in riboflavin-requiring (rf-) mutant cells of this aerob. PMID:6862382

  7. Genetic polymorphism of aldehyde oxidase in Donryu rats.

    PubMed

    Itoh, Kunio; Masubuchi, Akiko; Sasaki, Takamitsu; Adachi, Mayuko; Watanabe, Nobuaki; Nagata, Kiyoshi; Yamazoe, Yasushi; Hiratsuka, Masahiro; Mizugaki, Michinao; Tanaka, Yorihisa

    2007-05-01

    One of major metabolic pathways of [(+/-)-4-(4-cyanoanilino)-5,6-dihydro-7-hydroxy-7H-cyclopenta[d]-pyrimidine] (RS-8359), a selective and reversible monoamine oxidase type A inhibitor, is the aldehyde oxidase-catalyzed 2-hydroxylation at the pyrimidine ring. Donryu rats showed a dimorphic pattern for the 2-oxidation activity with about 20- to 40-fold variations in the Vmax/Km values between a low and a high activity group. The rats were classified as extensive metabolizers (EM) and poor metabolizers (PM) of RS-8359, of which ratios were approximately 1:1. One rat among the EM rats of each sex showed extremely high activity, and they were referred to as ultrarapid metabolizers. There was no significant difference in the expression levels of mRNA of aldehyde oxidase between the EM and PM rats. Analysis of nucleotide sequences showed four substitutions, of which the substitutions at 377G>A and 2604C>T caused 110Gly-Ser and 852Ala-Val amino acid changes, respectively. Amino acid residue 110 is located very near the second Fe-S center of aldehyde oxidase. Its change from nonchiral Gly to chiral Ser may result in a conformational change of aldehyde oxidase protein with the shift of isoelectric point value from 5.0 in the EM rats to 6.2 in the PM rats. The 110Gly-Ser amino acid substitution (377G>A) may be primarily responsible for the variations of aldehyde oxidase activity observed in Donryu rats, in addition to the difference of expression levels of aldehyde oxidase protein. If a new drug candidate is primarily metabolized by aldehyde oxidase, attention should be given to using a rat strain with high aldehyde oxidase activity and small individual variation. PMID:17293383

  8. Current status of NADPH oxidase research in cardiovascular pharmacology

    PubMed Central

    Rodiño-Janeiro, Bruno K; Paradela-Dobarro, Beatriz; Castiñeiras-Landeira, María Isabel; Raposeiras-Roubín, Sergio; González-Juanatey, José R; Álvarez, Ezequiel

    2013-01-01

    The implications of reactive oxygen species in cardiovascular disease have been known for some decades. Rationally, therapeutic antioxidant strategies combating oxidative stress have been developed, but the results of clinical trials have not been as good as expected. Therefore, to move forward in the design of new therapeutic strategies for cardiovascular disease based on prevention of production of reactive oxygen species, steps must be taken on two fronts, ie, comprehension of reduction-oxidation signaling pathways and the pathophysiologic roles of reactive oxygen species, and development of new, less toxic, and more selective nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitors, to clarify both the role of each NADPH oxidase isoform and their utility in clinical practice. In this review, we analyze the value of NADPH oxidase as a therapeutic target for cardiovascular disease and the old and new pharmacologic agents or strategies to prevent NADPH oxidase activity. Some inhibitors and different direct or indirect approaches are available. Regarding direct NADPH oxidase inhibition, the specificity of NADPH oxidase is the focus of current investigations, whereas the chemical structure-activity relationship studies of known inhibitors have provided pharmacophore models with which to search for new molecules. From a general point of view, small-molecule inhibitors are preferred because of their hydrosolubility and oral bioavailability. However, other possibilities are not closed, with peptide inhibitors or monoclonal antibodies against NADPH oxidase isoforms continuing to be under investigation as well as the ongoing search for naturally occurring compounds. Likewise, some different approaches include inhibition of assembly of the NADPH oxidase complex, subcellular translocation, post-transductional modifications, calcium entry/release, electron transfer, and genetic expression. High-throughput screens for any of these activities could provide new inhibitors. All this knowledge and the research presently underway will likely result in development of new drugs for inhibition of NADPH oxidase and application of therapeutic approaches based on their action, for the treatment of cardiovascular disease in the next few years. PMID:23983473

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

    SciTech Connect

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

    1995-05-24

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

  10. Plastid terminal oxidase 2 (PTOX2) is the major oxidase involved in chlororespiration in Chlamydomonas

    PubMed Central

    Houille-Vernes, Laura; Rappaport, Fabrice; Wollman, Francis-André; Alric, Jean; Johnson, Xenie

    2011-01-01

    By homology with the unique plastid terminal oxidase (PTOX) found in plants, two genes encoding oxidases have been found in the Chlamydomonas genome, PTOX1 and PTOX2. Here we report the identification of a knockout mutant of PTOX2. Its molecular and functional characterization demonstrates that it encodes the oxidase most predominantly involved in chlororespiration in this algal species. In this mutant, the plastoquinone pool is constitutively reduced under dark-aerobic conditions, resulting in the mobile light-harvesting complexes being mainly, but reversibly, associated with photosystem I. Accordingly, the ptox2 mutant shows lower fitness than wild type when grown under phototrophic conditions. Single and double mutants devoid of the cytochrome b6f complex and PTOX2 were used to measure the oxidation rates of plastoquinols via PTOX1 and PTOX2. Those lacking both the cytochrome b6f complex and PTOX2 were more sensitive to light than the single mutants lacking either the cytochrome b6f complex or PTOX2, which discloses the role of PTOX2 under extreme conditions where the plastoquinone pool is overreduced. A model for chlororespiration is proposed to relate the electron flow rate through these alternative pathways and the redox state of plastoquinones in the dark. This model suggests that, in green algae and plants, the redox poise results from the balanced accumulation of PTOX and NADPH dehydrogenase. PMID:22143777

  11. Plastid terminal oxidase 2 (PTOX2) is the major oxidase involved in chlororespiration in Chlamydomonas.

    PubMed

    Houille-Vernes, Laura; Rappaport, Fabrice; Wollman, Francis-André; Alric, Jean; Johnson, Xenie

    2011-12-20

    By homology with the unique plastid terminal oxidase (PTOX) found in plants, two genes encoding oxidases have been found in the Chlamydomonas genome, PTOX1 and PTOX2. Here we report the identification of a knockout mutant of PTOX2. Its molecular and functional characterization demonstrates that it encodes the oxidase most predominantly involved in chlororespiration in this algal species. In this mutant, the plastoquinone pool is constitutively reduced under dark-aerobic conditions, resulting in the mobile light-harvesting complexes being mainly, but reversibly, associated with photosystem I. Accordingly, the ptox2 mutant shows lower fitness than wild type when grown under phototrophic conditions. Single and double mutants devoid of the cytochrome b(6)f complex and PTOX2 were used to measure the oxidation rates of plastoquinols via PTOX1 and PTOX2. Those lacking both the cytochrome b(6)f complex and PTOX2 were more sensitive to light than the single mutants lacking either the cytochrome b(6)f complex or PTOX2, which discloses the role of PTOX2 under extreme conditions where the plastoquinone pool is overreduced. A model for chlororespiration is proposed to relate the electron flow rate through these alternative pathways and the redox state of plastoquinones in the dark. This model suggests that, in green algae and plants, the redox poise results from the balanced accumulation of PTOX and NADPH dehydrogenase. PMID:22143777

  12. The catalytic behaviour of monoamine oxidase.

    PubMed

    Tipton, K F; O'Carroll, A M; McCrodden, J M

    1987-01-01

    Evidence concerning the kinetic mechanism of the reaction catalyzed by monoamine oxidase is reviewed with particular reference to the possibility that the double-displacement mechanism followed by other substrates is not operative with benzylamine. The requirement for only one of the two products of the first half-reaction to be released in a double-displacement mechanism indicates that the available evidence does not exclude such a mechanism with benzylamine as the substrate. Cases in which substrates also act as time-dependent inhibitors are considered. The mechanism that can describe the inhibition and product formation is similar for the compounds MD 780236 and MPTP whereas that describing the effects of high concentrations of 2-phenethylamine is best described by a scheme involving inhibition occurring via an abortive complex. PMID:3295115

  13. Glucose oxidase immobilization onto carbon nanotube networking

    E-print Network

    Karachevtsev, V A; Zarudnev, E S; Karachevtsev, M V; Leontiev, V S; Linnik, A S; Lytvyn, O S; Plokhotnichenko, A M; Stepanian, S G

    2012-01-01

    When elaborating the biosensor based on single-walled carbon nanotubes (SWNTs), it is necessary to solve such an important problem as the immobilization of a target biomolecule on the nanotube surface. In this work, the enzyme (glucose oxidase (GOX)) was immobilized on the surface of a nanotube network, which was created by the deposition of nanotubes from their solution in 1,2-dichlorobenzene by the spray method. 1-Pyrenebutanoic acid succinimide ester (PSE) was used to form the molecular interface, the bifunctional molecule of which provides the covalent binding with the enzyme shell, and its other part (pyrene) is adsorbed onto the nanotube surface. First, the usage of such a molecular interface leaves out the direct adsorption of the enzyme (in this case, its activity decreases) onto the nanotube surface, and, second, it ensures the enzyme localization near the nanotube. The comparison of the resonance Raman (RR) spectrum of pristine nanotubes with their spectrum in the PSE environment evidences the creat...

  14. Coumarins: Auspicious Cholinesterase and Monoamine Oxidase Inhibitors.

    PubMed

    Orhan, Ilkay Erdogan; Gulcan, H Ozan

    2015-01-01

    Cholinesterase inhibition is the only current validated target in clinics in the treatment of Alzheimer's disease (AD). Therefore, there is continuous interest in the development and discovery of novel cholinesterase inhibitory molecules. Coumarins, beside their employment in other pharmacological groups, have also attracted attention to be utilized in cholinesterase inhibitory molecule discovery and development. Numerous studies so far indicated the natural and synthetic coumarin analogues that have the potential to inhibit acetylcholinesterase and butyrylcholinesterase enzymes. Since the pathophysiology of AD is highly complex and, in particular, monoamine oxidase (MAO) inhibitors are also utilized in clinic for disease symptoms, coumarin analogues, either natural or synthetic, that have the potential to inhibit cholinesterase or MAO enzymes are summarized within this review. PMID:25915613

  15. NADPH Oxidases in Lung Health and Disease

    PubMed Central

    Bernard, Karen; Hecker, Louise; Luckhardt, Tracy R.; Cheng, Guangjie

    2014-01-01

    Abstract Significance: The evolution of the lungs and circulatory systems in vertebrates ensured the availability of molecular oxygen (O2; dioxygen) for aerobic cellular metabolism of internal organs in large animals. O2 serves as the physiologic terminal acceptor of mitochondrial electron transfer and of the NADPH oxidase (Nox) family of oxidoreductases to generate primarily water and reactive oxygen species (ROS), respectively. Recent advances: The purposeful generation of ROS by Nox family enzymes suggests important roles in normal physiology and adaptation, most notably in host defense against invading pathogens and in cellular signaling. Critical issues: However, there is emerging evidence that, in the context of chronic stress and/or aging, Nox enzymes contribute to the pathogenesis of a number of lung diseases. Future Directions: Here, we review evolving functions of Nox enzymes in normal lung physiology and emerging pathophysiologic roles in lung disease. Antioxid. Redox Signal. 20, 2838–2853. PMID:24093231

  16. Function and Expression Analysis of Gibberellin Oxidases in Apple

    Microsoft Academic Search

    Huijun Zhao; Jiangli Dong; Tao Wang

    2010-01-01

    Three cDNAs, encoding gibberellin (GA) 20-oxidase (MdGA20ox1, identical to AB037114), 3-oxidase (MdGA3ox1), and 2-oxidase (MdGA2ox1), were isolated from apple cv. Fuji (Malus x domestica). Southern blot analysis indicated that each of these genes belongs to a gene family. Standard enzyme assays show that the\\u000a MdGA20ox1-MBP fusion protein can sequentially oxidize three times at C-20 position of GA12 and GA53 and

  17. Genomic Analysis of Xanthomonas oryzae Isolates from Rice Grown in the United States Reveals Substantial Divergence from Known X. oryzae Pathovars ? †

    PubMed Central

    Triplett, L. R.; Hamilton, J. P.; Buell, C. R.; Tisserat, N. A.; Verdier, V.; Zink, F.; Leach, J. E.

    2011-01-01

    The species Xanthomonas oryzae is comprised of two designated pathovars, both of which cause economically significant diseases of rice in Asia and Africa. Although X. oryzae is not considered endemic in the United States, an X. oryzae-like bacterium was isolated from U.S. rice and southern cutgrass in the late 1980s. The U.S. strains were weakly pathogenic and genetically distinct from characterized X. oryzae pathovars. In the current study, a draft genome sequence from two U.S. Xanthomonas strains revealed that the U.S. strains form a novel clade within the X. oryzae species, distinct from all strains known to cause significant yield loss. Comparative genome analysis revealed several putative gene clusters specific to the U.S. strains and supported previous reports that the U.S. strains lack transcriptional activator-like (TAL) effectors. In addition to phylogenetic and comparative analyses, the genome sequence was used for designing robust U.S. strain-specific primers, demonstrating the usefulness of a draft genome sequence in the rapid development of diagnostic tools. PMID:21515727

  18. Immunocytochemical localization of urate oxidase, fatty acyl-CoA oxidase, and catalase in bovine kidney peroxisomes.

    PubMed

    Usuda, N; Usman, M I; Reddy, M K; Hashimoto, T; Reddy, J K; Rao, M S

    1988-03-01

    We investigated the localization of urate oxidase, peroxisomal fatty acyl-CoA oxidase, and catalase in bovine kidney by immunoblot analysis and protein A-gold immunocytochemistry, using the respective polyclonal monospecific antibodies raised against the enzymes purified from rat liver. By immunoblot analysis, these three proteins were detected in bovine kidney and bovine liver homogenates. Subcellular localization of these three enzymes in kidney was ascertained by protein A-gold immunocytochemical staining of Lowicryl K4M-embedded tissue. Peroxisomes in bovine kidney cortical epithelium possessed crystalloid cores or nucleoids, which were found to be the exclusive sites of urate oxidase localization. The limiting membrane, the marginal plate, and the matrix of renal peroxisomes were negative for urate oxidase staining. In contrast, catalase and fatty acyl-CoA oxidase were found in the peroxisome matrix. These results demonstrate that, unlike rat kidney peroxisomes which lack urate oxidase, peroxisomes of bovine kidney contain this enzyme as well as peroxisomal fatty acyl-CoA oxidase. PMID:3343509

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

    PubMed

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

    1997-05-01

    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 aerogenes, Serratia marcescens, Proteus spp., and Providencia spp. BMS-180680 had moderate activities (MIC90s of 2 to 8 microg/ml) against Citrobacter freundii, Morganella morganii, Shigella spp., and non-E. aerogenes Enterobacter spp. BMS-180680 was the only antibiotic evaluated that was active against >90% of the Pseudomonas aeruginosa (MIC90, 0.25 microg/ml), Burkholderia cepacia, and Stenotrophomonas maltophilia (MIC90s, 1 microg/ml) strains tested. BMS-180680 was inactive against most strains of Pseudomonas fluorescens, Pseudomonas stutzeri, Pseudomonas diminuta, and Burkholderia pickettii. BMS-180680 was moderately active (MIC90s of 4 to 8 microg/ml) against Alcaligenes spp. and Acinetobacter lwoffii and less active (MIC90, 16 microg/ml) against Acinetobacter calcoaceticus-Acinetobacter baumanii complex. BMS-180680 lacked activity against gram-positive bacteria and anaerobic bacteria. Both tonB and cir fiu double mutants of E. coli had greatly decreased susceptibility to BMS-180680. Of the TEM, PSE, and chromosomal-encoded beta-lactamases tested, only the K1 enzyme hydrolyzed BMS-180680 to any measurable extent. Like aztreonam, BMS-180680 bound preferentially to penicillin-binding protein 3. The MICs of BMS-180680 were not influenced by the presence of hematin or 5% sheep blood in the test medium or with incubation in an atmosphere containing 5% CO2. BMS-180680 MICs obtained under strict anaerobic conditions were significantly higher than those obtained in ambient air. PMID:9145861

  20. Genetic association of catechol-O-methyltransferase val(158)met polymorphism in Saudi schizophrenia patients.

    PubMed

    Al-Asmary, S; Kadasah, S; Arfin, M; Tariq, M; Al-Asmari, A

    2014-01-01

    Schizophrenia is a complex neuropsychiatric disorder strongly associated with dopamine dysregulation. Catechol-O-methyl-transferase (COMT) is a candidate gene for schizophrenia that encodes an enzyme involved in the metabolic inactivation of dopamine. The COMT Val(158)Met polymorphism has been associated with schizophrenia and has significant inter- and intra-ethnic variations. We examined a possible association between the COMT Val(158)Met polymorphism and schizophrenia in Saudis, taking into account gender and functional symptoms. Saudi subjects including 172 unrelated schizophrenia patients and 177 matched controls were analyzed for allele and genotype distribution of the COMT Val(158)Met polymorphism. We found significant differences in allele and genotype frequencies between patients and controls. The frequencies of Met(158) allele (A) and genotype Val(158)Met (GA) were significantly higher in patients compared to those in controls. On the other hand, the frequencies of Val(158) allele (G) and genotype Val(158)Val (GG) were significantly higher in controls than those in patients. We found a significant association of the COMT Val(158)Met polymorphism with schizophrenia. Moreover, male patients with the COMT Val(158)Met polymorphism had increased risk for schizophrenia compared to female subjects. However, no association was noticed with the COMT Val(158)Met polymorphism and negative or positive symptoms of schizophrenia. These results provide evidence for a role of the COMT Val(158)Met polymorphism in the etiopathophysiology of schizophrenia in Saudi population. It appears that the association of the COMT Val(158)Met polymorphism with schizophrenia is mediated by gender. PMID:24782165

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

    PubMed Central

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

    2014-01-01

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

  2. Differential regulation of catechol-O-methyltransferase expression in a mouse model of aggression

    PubMed Central

    Che, Shaoli; Hashim, Audrey; Zavadil, Jiri; Cancro, Robert; Lee, Sang H.; Petkova, Eva; Sershen, Henry W.; Volavka, Jan

    2011-01-01

    This study was designed to understand molecular and cellular mechanisms underlying aggressive behaviors in mice exposed to repeated interactions in their homecage with conspecifics. A resident–intruder procedure was employed whereby two males were allowed to interact for 10 min trials, and aggressive and/or submissive behaviors (e.g., degree of attacking, biting, chasing, grooming, rearing, or upright posture) were assessed. Following 10 days of behavioral trials, brains were removed and dissected into specific regions including the cerebellum, frontal cortex, hippocampus, midbrain, pons, and striatum. Gene expression analysis was performed using real-time quantitative polymerase-chain reaction (qPCR) for catechol-O-methyltransferase (COMT) and tyrosine hydroxylase (TH). Compared to naive control mice, significant up regulation of COMT expression of residents was observed in the cerebellum, frontal cortex, hippocampus, midbrain, and striatum; in all of these brain regions the COMT expression of residents was also significantly higher than that of intruders. The intruders also had a significant down regulation (compared to naive control mice) within the hippocampus, indicating a selective decrease in COMT expression in the hippocampus of submissive subjects. Immunoblot analysis confirmed COMT up regulation in the midbrain and hippocampus of residents and down regulation in intruders. qPCR analysis of TH expression indicated significant up regulation in the midbrain of residents and concomitant down regulation in intruders. These findings implicate regionally- and behaviorally-specific regulation of COMT and TH expression in aggressive and submissive behaviors. Additional molecular and cellular characterization of COMT, TH, and other potential targets is warranted within this animal model of aggression. PMID:21512897

  3. How Metal Substitution Affects the Enzymatic Activity of Catechol-O-Methyltransferase

    PubMed Central

    Sparta, Manuel; Alexandrova, Anastassia N.

    2012-01-01

    Catechol-O-methyltransferase (COMT) degrades catecholamines, such as dopamine and epinephrine, by methylating them in the presence of a divalent metal cation (usually Mg(II)), and S-adenosyl-L-methionine. The enzymatic activity of COMT is known to be vitally dependent on the nature of the bound metal: replacement of Mg(II) with Ca(II) leads to a complete deactivation of COMT; Fe(II) is slightly less than potent Mg(II), and Fe(III) is again an inhibitor. Considering the fairly modest role that the metal plays in the catalyzed reaction, this dependence is puzzling, and to date remains an enigma. Using a quantum mechanical / molecular mechanical dynamics method for extensive sampling of protein structure, and first principle quantum mechanical calculations for the subsequent mechanistic study, we explicate the effect of metal substitution on the rate determining step in the catalytic cycle of COMT, the methyl transfer. In full accord with experimental data, Mg(II) bound to COMT is the most potent of the studied cations and it is closely followed by Fe(II), whereas Fe(III) is unable to promote catalysis. In the case of Ca(II), a repacking of the protein binding site is observed, leading to a significant increase in the activation barrier and higher energy of reaction. Importantly, the origin of the effect of metal substitution is different for different metals: for Fe(III) it is the electronic effect, whereas in the case of Ca(II) it is instead the effect of suboptimal protein structure. PMID:23056605

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

    PubMed Central

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

    2012-01-01

    Polycyclic aromatic hydrocarbons (PAH) are ubiquitous environmental pollutants. They are procarcinogens requiring metabolic activation to elicit their deleterious effects. Aldo-keto reductases (AKR) catalyze the oxidation of proximate carcinogenic PAH trans-dihydrodiols to yield electrophilic and redox-active PAH o-quinones. AKRs are also found to be capable of reducing PAH o-quinones to form PAH catechols. The interconversion of o-quinones and catechols results in the redox-cycling of PAH o-quinones to give rise to the generation of reactive oxygen species and subsequent oxidative DNA damage. On the other hand, PAH catechols can be intercepted through phase II metabolism by which PAH o-quinones could be detoxified and eliminated. The aim of the present review is to summarize the role of human AKRs in the metabolic activation/detoxication of PAH and the relevance of phase II conjugation reactions to human lung carcinogenesis. PMID:23162467

  5. A trial of minimization of chromosome 7 in Aspergillus oryzae by multiple chromosomal deletions

    Microsoft Academic Search

    Feng Jie Jin; Tadashi Takahashi; Michiyo Utsushikawa; Toshi Furukido; Michiyo Nishida; Masahiro Ogawa; Masahumi Tokuoka; Yasuji Koyama

    2010-01-01

    We aim to create an Aspergillus oryzae mutant with a highly reduced chromosome, but better growth, by eliminating the nonessential regions coding various dispensable\\u000a functions for its better industrial use. In our previous study, we successfully determined the outline of essential and nonessential\\u000a regions by constructing a series of large chromosomal deletions in A. oryzae chromosome 7. Based on these

  6. Purification and characterization of the pectin lyase produced by Rhizopus oryzae grown on orange peels

    Microsoft Academic Search

    Hossam S. HAMDY

    Potentiality of Rhizopus oryzae to utilize orange peels under solid state fermentation conditions to produce macerating fluid with high cellulolytic and pectinolytic activities were confirmed in this work. Addition of NH4NO3 and NH4Cl to the fermentation medium improved the macerating potentiality due to an increase in enzyme levels. The pectin lyase (PL) secreted by R. oryzae under these conditions was

  7. Discovery of a novel superfamily of type III polyketide synthases in Aspergillus oryzae

    Microsoft Academic Search

    Yasuyo Seshime; Praveen Rao Juvvadi; Isao Fujii; Katsuhiko Kitamoto

    2005-01-01

    Identification of genes encoding type III polyketide synthase (PKS) superfamily members in the industrially useful filamentous fungus, Aspergillus oryzae, revealed that their distribution is not specific to plants or bacteria. Among other Aspergilli (Aspergillus nidulans and Aspergillus fumigatus), A. oryzae was unique in possessing four chalcone synthase (CHS)-like genes (csyA, csyB, csyC, and csyD). Expression of csyA, csyB, and csyD

  8. Cyanobacteria-mediated phenylpropanoids and phytohormones in rice ( Oryza sativa ) enhance plant growth and stress tolerance

    Microsoft Academic Search

    Dhananjaya P. Singh; Ratna Prabha; Mahesh S. Yandigeri; Dilip K. Arora

    Phenylpropanoids, flavonoids and plant growth regulators in rice (Oryza sativa) variety (UPR 1823) inoculated with different cyanobacterial strains namely Anabaena oryzae, Anabaena doliolum, Phormidium fragile, Calothrix geitonos, Hapalosiphon intricatus, Aulosira fertilissima,\\u000a Tolypothrix tenuis, Oscillatoria acuta and Plectonema boryanum were quantified using HPLC in pot conditions after 15 and 30 days. Qualitative analysis of the induced compounds using reverse\\u000a phase HPLC and

  9. Efficacy of diflubenzuron plus methoprene against Sitophilus oryzae and Rhyzopertha dominica in stored sorghum

    Microsoft Academic Search

    Gregory J. Daglish; Barry E. Wallbank

    2005-01-01

    The efficacy of diflubenzuron (1mgkg?1)+methoprene (1mgkg?1) against Sitophilus oryzae (L.) and Rhyzopertha dominica (F.) in sorghum was evaluated in a silo-scale trial in southeast Queensland, Australia. Sorghum is normally protected from a wide range of insects by mixtures of grain protectants. The chitin synthesis inhibitor diflubenzuron was evaluated as a potential new protectant for S. oryzae in combination with the

  10. Functional models for catechol dioxygenases: iron(III) complexes of cis-facially coordinating linear 3N ligands.

    PubMed

    Velusamy, Marappan; Mayilmurugan, Ramasamy; Palaniandavar, Mallayan

    2005-05-01

    A series of 1:1 iron(III) complexes of simple and sterically hindered tridentate 3N donor ligands have been synthesized and studied as functional models for catechol dioxygenases. All of them are of the type [FeLCl3], where L is bis(pyrid-2-yl-methyl)amine (L1), N,N-bis(benzimidazol-2-ylmethyl)amine (L2), N-methyl-N'-(pyrid-2-ylmethyl)ethylenediamine (L3), N,N-dimethyl-N'-(pyrid-2-ylmethyl)-ethylenediamine (L4) and N-phenyl-N'-(pyrid-2-ylmethyl)ethylenediamine (L5). They have been characterised by spectral and electrochemical methods. The X-ray crystal structure of the complex [Fe(L4)Cl3] has been successfully determined. The complex crystallizes in the triclinic space group P1 with a = 7.250(6), b = 8.284(3), c = 12.409(4) angstroms, alpha = 80.84(3) degrees, beta = 86.76(6) degrees, gamma = 72.09(7) degrees and Z = 2. It possesses a distorted octahedral geometry in which the L4 ligand is cis-facially coordinated to iron(III) and the chloride ions occupy the remaining coordination sites. The systematic variation in the ligand donor atom type significantly influences the Lewis acidity of the iron(III) center and hence the binding interaction of the complexes with simple and substituted catechols. The spectroscopic and electrochemical properties of the catecholate complexes generated in situ have been investigated. All the complexes catalyze mainly the oxidative intradiol cleavage of 3,5-di-tert-butylcatechol (H2DBC) in the presence of dioxygen, which is unexpected of the cis-facial coordination of the ligands. The rate of intradiol catechol cleavage reaction depends upon the Lewis acidity of iron(III) center and steric demand and hydrogen-bonding functionalities of the ligands. Interestingly, the electron-sink property of N-phenyl substituent in [Fe(L5)Cl3] complex leads to enhancement in rate of cleavage. All these observations provide support to the substrate activation mechanism proposed for intradiol-cleaving enzymes. PMID:15833326

  11. Multiple-dose clinical pharmacology of the catechol-O-methyl-transferase inhibitor tolcapone in elderly subjects

    Microsoft Academic Search

    J. Dingemanse; K. Jorga; G. Zürcher; B. Fotteler; G. Sedek; T. Nielsen; P. van Brummelen

    1996-01-01

    .  \\u000a Objective: The purpose of this study was to assess the multiple-dose clinical pharmacology of tolcapone, a novel catechol-O-methyltransferase (COMT) inhibitor, in elderly subjects. \\u000a \\u000a Methods:\\u000a \\u000a \\u000a The drug was administered orally t.i.d. for 7 days to four sequential groups of eight elderly subjects (gender ratio1:1) at\\u000a doses of 100, 200, 400 and 800 mg in a double-blind, randomised, placebo-controlled, ascending-multiple-dose design.

  12. Rapid diversification of five Oryza AA genomes associated with rice adaptation

    PubMed Central

    Zhang, Qun-Jie; Zhu, Ting; Xia, En-Hua; Shi, Chao; Liu, Yun-Long; Zhang, Yun; Liu, Yuan; Jiang, Wen-Kai; Zhao, You-Jie; Mao, Shu-Yan; Zhang, Li-Ping; Huang, Hui; Jiao, Jun-Ying; Xu, Ping-Zhen; Yao, Qiu-Yang; Zeng, Fan-Chun; Yang, Li-Li; Gao, Ju; Tao, Da-Yun; Wang, Yue-Ju; Bennetzen, Jeffrey L.; Gao, Li-Zhi

    2014-01-01

    Comparative genomic analyses among closely related species can greatly enhance our understanding of plant gene and genome evolution. We report de novo-assembled AA-genome sequences for Oryza nivara, Oryza glaberrima, Oryza barthii, Oryza glumaepatula, and Oryza meridionalis. Our analyses reveal massive levels of genomic structural variation, including segmental duplication and rapid gene family turnover, with particularly high instability in defense-related genes. We show, on a genomic scale, how lineage-specific expansion or contraction of gene families has led to their morphological and reproductive diversification, thus enlightening the evolutionary process of speciation and adaptation. Despite strong purifying selective pressures on most Oryza genes, we documented a large number of positively selected genes, especially those genes involved in flower development, reproduction, and resistance-related processes. These diversifying genes are expected to have played key roles in adaptations to their ecological niches in Asia, South America, Africa and Australia. Extensive variation in noncoding RNA gene numbers, function enrichment, and rates of sequence divergence might also help account for the different genetic adaptations of these rice species. Collectively, these resources provide new opportunities for evolutionary genomics, numerous insights into recent speciation, a valuable database of functional variation for crop improvement, and tools for efficient conservation of wild rice germplasm. PMID:25368197

  13. Development of INDEL markers to discriminate all genome types rapidly in the genus Oryza

    PubMed Central

    Yamaki, Shinichiro; Ohyanagi, Hajime; Yamasaki, Masanori; Eiguchi, Mitsugu; Miyabayashi, Toshie; Kubo, Takahiko; Kurata, Nori; Nonomura, Ken-Ichi

    2013-01-01

    The wild Oryza species are rich in genetic diversity and are good resources for modern breeding of rice varieties. The reliable ex situ conservation of various genetic resources supports both basic and applied rice research. For this purpose, we developed PCR-based and co-dominant insertion/deletion (INDEL) markers which enable the discrimination of the genome types or species in the genus Oryza. First, 12,107 INDEL candidate sequences were found in the BAC end sequences for 12 Oryza species available in public databases. Next, we designed PCR primers for INDEL-flanking sequences to match the characteristics of each INDEL, based on an assessment of their likelihood to give rise to a single or few PCR products in all 102 wild accessions, covering most Oryza genome types. Then, we selected 22 INDEL markers to discriminate all genome types in the genus Oryza. A phylogenetic tree of 102 wild accessions and two cultivars according to amplicon polymorphisms for the 22 INDEL markers corresponded well to those in previous studies, indicating that the INDEL markers developed in this study were a useful tool to improve the reliability of identification of wild Oryza species in the germplasm stocks. PMID:24273419

  14. Development of INDEL markers to discriminate all genome types rapidly in the genus Oryza.

    PubMed

    Yamaki, Shinichiro; Ohyanagi, Hajime; Yamasaki, Masanori; Eiguchi, Mitsugu; Miyabayashi, Toshie; Kubo, Takahiko; Kurata, Nori; Nonomura, Ken-Ichi

    2013-09-01

    The wild Oryza species are rich in genetic diversity and are good resources for modern breeding of rice varieties. The reliable ex situ conservation of various genetic resources supports both basic and applied rice research. For this purpose, we developed PCR-based and co-dominant insertion/deletion (INDEL) markers which enable the discrimination of the genome types or species in the genus Oryza. First, 12,107 INDEL candidate sequences were found in the BAC end sequences for 12 Oryza species available in public databases. Next, we designed PCR primers for INDEL-flanking sequences to match the characteristics of each INDEL, based on an assessment of their likelihood to give rise to a single or few PCR products in all 102 wild accessions, covering most Oryza genome types. Then, we selected 22 INDEL markers to discriminate all genome types in the genus Oryza. A phylogenetic tree of 102 wild accessions and two cultivars according to amplicon polymorphisms for the 22 INDEL markers corresponded well to those in previous studies, indicating that the INDEL markers developed in this study were a useful tool to improve the reliability of identification of wild Oryza species in the germplasm stocks. PMID:24273419

  15. Chromosome location of Oryza sativa recombination linkage groups.

    PubMed Central

    Gustafson, J P; Dillé, J E

    1992-01-01

    In situ hybridization, a powerful tool for the molecular cytogeneticist, can be used to physically map repetitive, low-copy, and unique DNA sequences in plant chromosomes. With the availability of a recombination map in Oryza sativa L. and an improved in situ hybridization technique, this study was designed to establish the relationship between the genetic and physical distances of the rice restriction fragment length polymorphism map. Analysis indicated that considerable variation can exist between genetic and physical maps. A 183-centimorgan linkage map for chromosome 2 covered less than 50% of the chromosome and did not include the centromere, whereas a 91-centimorgan linkage map for chromosome 1 covered approximately 80% of the chromosome. The results indicated that there are potential "hot" and "cold" spots of recombination and polymorphisms in rice, which involve both genes and restriction fragment length polymorphisms. Images PMID:1356266

  16. Drimane sesquiterpenoids from the Aspergillus oryzae QXPC-4.

    PubMed

    Ren, Ren; Chen, Chao-Jun; Hu, Sha-Sha; Ge, Hui-Ming; Zhu, Wen-Yong; Tan, Ren-Xiang; Jiao, Rui-Hua

    2015-03-01

    Three new drimane sesquiterpenoids, astellolides C-E (1-3, resp.), four new drimane sesquiterpenoid p-hydroxybenzoates, astellolides F-I (4-7, resp.), together with two known compounds astellolides A and B (8 and 9, resp.), have been isolated from the liquid culture of Aspergillus oryzae (strain No.?QXPC-4). Their structures were established by comprehensive analysis of spectroscopic data. The relative and absolute configurations were determined on the basis of NOESY and CD data, together with single-crystal X-ray diffraction analyses of compounds 1-3. The metabolites were evaluated for their cytotoxic activities, however, no compounds showed a significant cytotoxicity against the tested cell lines at a concentration of 20??M. PMID:25766910

  17. Monoolein production by triglycerides hydrolysis using immobilized Rhizopus oryzae lipase.

    PubMed

    Ghattas, Nesrine; Abidi, Ferid; Galai, Said; Marzouki, M Nejib; Salah, Abderraouf Ben

    2014-07-01

    Lipase extracted from Rhizopus oryzae was immobilized in alginate gel beads. The effects of the immobilization conditions, such as, alginate concentration, CaCl2 concentration and amount of initial enzyme on retained activity (specific activity ratio of entrapped active lipase to free lipase) were investigated. The optimal conditions for lipase entrapment were determined: 2% (w/v) alginate concentration, 100mM CaCl2 and enzyme ratio of 2000IU/mL.In such conditions, immobilized lipase by inclusion in alginate showed a highest stability and activity, on olive oil hydrolysis reaction where it could be reused for 10 cycles. After 15min of hydrolysis reaction, the mass composition of monoolein, diolein and triolein were about 78%, 10% and 12%. Hydrolysis' products purification by column chromatography lead to a successful separation of reaction compounds and provide a pure fraction of monoolein which is considered as the widest used emulsifier in food and pharmaceutical industries. PMID:24755261

  18. Fabrication of mussel-inspired highly adhesive honeycomb films containing catechol groups and their applications for substrate-independent porous templates.

    PubMed

    Saito, Yuta; Kawano, Takahito; Shimomura, Masatsugu; Yabu, Hiroshi

    2013-04-25

    Porous surface patterns are used in a wide variety of practical applications. Honeycomb-patterned porous polymer films are good templates for preparing porous surfaces due to their simple fabrication and the arrangement of pores on the surface. Catechol groups include in adhesive protein of mussels have attracted much attention due to their highly and substrate-independent adhesive properties. In this paper, highly and substrate-independent adhesive honeycomb-patterned porous polymer films are prepared by using amphiphilic copolymer having catechol moieties. Furthermore, porous surface patterns are transferred on various organic or inorganic substrates by wet etching with using adhesive honeycomb films as templates. PMID:23508892

  19. PhyA, a secreted protein of Xanthomonas oryzae pv. oryzae, is required for optimum virulence and growth on phytic acid as a sole phosphate source.

    PubMed

    Chatterjee, Subhadeep; Sankaranarayanan, Rajan; Sonti, Ramesh V

    2003-11-01

    Xanthomonas oryzae pv. oryzae causes bacterial leaf blight, a serious disease of rice. We have identified a novel virulence deficient mutant (BXO1691) of X. oryzae pv. oryzae that has a Tn5 insertion in an open reading frame (phyA; putative phytase A) encoding a 373-amino acid (aa) protein containing a 28-aa predicted signal peptide. Extracellular protein profiles revealed that a 38-kDa band is absent in phyA mutants as compared with phyA+ strains. A BLAST search with phyA and its deduced polypeptide sequence indicated significant similarity with conserved hypothetical proteins in Xanthomonas axonopodis pv. citri and Xanthomonas campestris pv. campestris and limited homology to secreted phytases of Bacillus species. Homology modeling with a Bacillus phytase as the template suggests that the PhyA protein has a similar six-bladed beta-propeller architecture and exhibits conservation of certain critical active site residues. Phytases are enzymes that are involved in degradation of phytic acid (inositol hexaphosphate), a stored form of phosphate in plants. The phyA mutants exhibit a growth deficiency in media containing phytic acid as a sole phosphate source. Exogenous phosphate supplementation promotes migration of phyA X. oryzae pv. oryzae mutants in rice leaves. These results suggest that the virulence deficiency of phyA mutants is, at least in part, due to inability to use host phytic acid as a source of phosphate. phyA-like genes have not been previously reported to be involved in the virulence of any plant pathogenic bacterium. PMID:14601665

  20. The Xanthomonas oryzae pv. oryzae PilZ Domain Proteins Function Differentially in Cyclic di-GMP Binding and Regulation of Virulence and Motility.

    PubMed

    Yang, Fenghuan; Tian, Fang; Chen, Huamin; Hutchins, William; Yang, Ching-Hong; He, Chenyang

    2015-07-01

    The PilZ domain proteins have been demonstrated to be one of the major types of receptors mediating cyclic di-GMP (c-di-GMP) signaling pathways in several pathogenic bacteria. However, little is known about the function of PilZ domain proteins in c-di-GMP regulation of virulence in the bacterial blight pathogen of rice Xanthomonas oryzae pv. oryzae. Here, the roles of PilZ domain proteins PXO_00049 and PXO_02374 in c-di-GMP binding, regulation of virulence and motility, and subcellular localization were characterized in comparison with PXO_02715, identified previously as an interactor with the c-di-GMP receptor Filp to regulate virulence. The c-di-GMP binding motifs in the PilZ domains were conserved in PXO_00049 and PXO_02374 but were less well conserved in PXO_02715. PXO_00049 and PXO_02374 but not PXO_02715 proteins bound to c-di-GMP with high affinity in vitro, and the R(141) and R(10) residues in the PilZ domains of PXO_00049 and PXO_02374, respectively, were crucial for c-di-GMP binding. Gene deletion of PXO_00049 and PXO_02374 resulted in significant increases in virulence and hrp gene transcription, indicating their negative regulation of virulence via type III secretion system expression. All mutants showed significant changes in sliding motility but not exopolysaccharide production and biofilm formation. In trans expression of the full-length open reading frame (ORF) of each gene in the relevant mutants led to restoration of the phenotype to wild-type levels. Moreover, PXO_00049 and PXO_02374 displayed mainly multisite subcellular localizations, whereas PXO_02715 showed nonpolar distributions in the X. oryzae pv. oryzae cells. Therefore, this study demonstrated the different functions of the PilZ domain proteins in mediation of c-di-GMP regulation of virulence and motility in X. oryzae pv. oryzae. PMID:25911481

  1. Bioelectrochemical characteristics of cholesterol oxidase immobilized in a polyaniline film

    Microsoft Academic Search

    Haiyan Wang; Shaolin Mu

    1999-01-01

    Cholesterol oxidase has been immobilized in polyaniline film by the electrochemical doping method. The measurements of the response current are carried out in the solutions containing cholesterol and Triton X-100 of 5% and 1%, respectively. The latter is necessary for solubilizing cholesterol. The response current of the polyaniline cholesterol oxidase electrode increases with increasing potential from 0.35 to 0.60 V

  2. Identification and Characterization of Two Novel DSF-Controlled Virulence-Associated Genes Within the nodB-rhgB Locus of Xanthomonas oryzae pv. oryzicola Rs105.

    PubMed

    Song, Zhiwei; Zhao, Yancun; Zhou, Xingyang; Wu, Guichun; Zhang, Yuqiang; Qian, Guoliang; Liu, Fengquan

    2015-05-01

    Xanthomonas oryzae pv. oryzicola and X. oryzae pv. oryzae are two pathovars of X. oryzae that cause leaf streak and blight in rice, respectively. These two bacterial pathogens cause different disease symptoms by utilizing different infection sites on rice. Compared with X. oryzae pv. oryzae, the molecular virulence mechanism of X. oryzae pv. oryzicola remains largely unknown. Previously, we identified a unique diffusible signal factor (DSF)-controlled virulence-related gene (hshB) in X. oryzae pv. oryzicola Rs105 located in the nodB-rghB locus, which is absent in X. oryzae pv. oryzae PXO99(A). In the present study, we identified two additional genes within this locus (hshA and hshC) that were unique to X. oryzae pv. oryzicola Rs105 compared with X. oryzae pv. oryzae PXO99(A), and we found that the transcription of these genes was regulated by DSF signaling in X. oryzae pv. oryzicola. The mutation of these genes impaired the virulence of the wild-type Rs105 when using a low inoculation density of X. oryzae pv. oryzicola. In contrast to hshB, the mutation of these genes did not have any visible effect on characterized virulence-related functions, including in vitro growth, extracellular polysaccharide production, extracellular protease activity, and antioxidative ability. However, we found that mutation of hshA or hshC significantly reduced the in planta growth ability and epiphytic survival level of X. oryzae pv. oryzicola cells, which was the probable mechanisms of involvement of these two genes in virulence. Collectively, our studies of X. oryzae pv. oryzicola have identified two novel DSF-controlled virulence-associated genes (hshA and hshC), which will add to our understanding of the regulatory mechanisms of conserved DSF virulence signaling in Xanthomonas species. PMID:26020828

  3. Vacuolar Membrane Dynamics in the Filamentous Fungus Aspergillus oryzae

    PubMed Central

    Shoji, Jun-ya; Arioka, Manabu; Kitamoto, Katsuhiko

    2006-01-01

    Vacuoles in filamentous fungi are highly pleomorphic and some of them, e.g., tubular vacuoles, are implicated in intra- and intercellular transport. In this report, we isolated Aovam3, the homologue of the Saccharomyces cerevisiae VAM3 gene that encodes the vacuolar syntaxin, from Aspergillus oryzae. In yeast complementation analyses, the expression of Aovam3 restored the phenotypes of both ?vam3 and ?pep12 mutants, suggesting that AoVam3p is likely the vacuolar and/or endosomal syntaxin in A. oryzae. FM4-64 [N-(3-triethylammoniumpropyl)-4-(p-diethylaminophenyl-hexatrienyl)pyridinium dibromide] and CMAC (7-amino-4-chloromethylcoumarin) staining confirmed that the fusion protein of enhanced green fluorescent protein (EGFP) with AoVam3p (EGFP-AoVam3p) localized on the membrane of the pleomorphic vacuolar networks, including large spherical vacuoles, tubular vacuoles, and putative late endosomes/prevacuolar compartments. EGFP-AoVam3p-expressing strains allowed us to observe the dynamics of vacuoles with high resolutions, and moreover, led to the discovery of several new aspects of fungal vacuoles, which have not been discovered so far with conventional staining methods, during different developmental stages. In old hyphae, EGFP fluorescence was present in the entire lumen of large vacuoles, which occupied most of the cell, indicating that degradation of cytosolic materials had occurred in such hyphae via an autophagic process. In hyphae that were not in contact with nutrients, such as aerial hyphae and hyphae that grew on a glass surface, vacuoles were composed of small punctate structures and tubular elements that often formed reticulum-like networks. These observations imply the presence of so-far-unrecognized roles of vacuoles in the development of filamentous fungi. PMID:16467481

  4. Genetic structure of Oryza rufipogon Griff. in China.

    PubMed

    Wang, M X; Zhang, H L; Zhang, D L; Qi, Y W; Fan, Z L; Li, D Y; Pan, D J; Cao, Y S; Qiu, Z E; Yu, P; Yang, Q W; Wang, X K; Li, Z C

    2008-12-01

    Oryza rufipogon Griff. (common wild rice; CWR) is the ancestor of Asian cultivated rice (Oryza sativa L.). Investigation of the genetic structure and diversity of CWR in China will provide information about the origin of cultivated rice and the grain quality and yield. In this study, we used 36 simple sequence repeat (SSR) markers to assay 889 accessions, which were highly representative of whole germplasm in China. The analysis revealed a hierarchical genetic structure within CWR. First, CWR has diverged into two ecotypic populations, a south subtropical population (SSP) and a middle subtropical population (MSP), probably owing to natural selection by the different climates. The distribution of specific alleles and haplotypes indicated that Chinese CWR had both indica-like and japonica-like variations; the SSP was an indica-like type, whereas the MSP was more japonica-like. The SSP and MSP further diverged into five (HN, GD-GX1, GX2, FJ and YN) and two (JX-HuN1 and HuN2) geographical populations, respectively. The genetic data suggest the isolation by distance, although water systems also appear to play an important role in the formation of homogenous populations, and occasionally landscape was also involved. The population GD-GX1, which grew widely in Guangdong and Guangxi provinces, was the largest geographical population in China. It had a high level of genetic diversity (GD) and the closest genetic relationship with other inferred populations. The population HN, with the smallest SSR molecular weights and the highest level of GD, may be the most ancestral population. PMID:18827837

  5. Confirmation of a blocked amino terminus of sulfhydryl oxidase

    SciTech Connect

    Janolino, V.G.; Morrison-Rowe, S.J.; Swaisgood, H.E. (North Carolina State Univ., Raleigh (USA))

    1990-09-01

    The isolation of sulfhydryl oxidase from bovine milk in a suitably pure form for sequencing was carried out by transient covalent affinity chromatography of diafiltered whey using cysteinylsuccinamidopropyl-glass as matrix. The glutathione-eluted proteins were separated by SDS-PAGE. By radiolabeling the affinity chromatography-purified enzyme with ({sup 14}C)iodoacetate before subjecting to SDS-PAGE, the sulfhydryl oxidase band was identified, because sulfhydryl oxidase is known to be inactivated by alkylation of one sulfhydryl group per mole. The results confirmed that sulfhydryl oxidase corresponds to the 85 ({plus minus} 5)-kDa band observed on SDS-PAGE. The protein band corresponding to radiolabeled sulfhydryl oxidase was recovered from SDS-PAGE gels by electrophoretic elution and by electroblotting on polyvinylidene difluoride membrane and subjected to gas phase sequencing. Precautions were taken during electrophoretic elution to prevent reactions that result in N-terminal blocking. Both methods of protein recovery yielded negative results when subjected to sequence analysis indicating that the N-terminus of sulfhydryl oxidase is blocked.

  6. Purification of enzymatically active human lysyl oxidase and lysyl oxidase-like protein from Escherichia coli inclusion bodies

    Microsoft Academic Search

    Sang Taek Jung; Moon Suk Kim; Ji Yeon Seo; Hyung Chul Kim; Youngho Kim

    2003-01-01

    Lysyl oxidase (LOX) is an extracellular copper dependent enzyme catalyzing lysine-derived cross-links in extracellular matrix proteins. Recent molecular cloning has revealed the existence of a LOX family consisting of LOX and four lysyl oxidase-like proteins (LOXLs; LOXL, LOXL2, LOXL3, and LOXL4). Each member of the LOX family contains a copper-binding domain, residues for lysyl-tyrosyl quinone, and a cytokine receptor-like domain.

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

    PubMed

    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

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  9. Bioactive surface modification of metal oxides via catechol-bearing modular peptides: multivalent-binding, surface retention, and peptide bioactivity.

    PubMed

    Tang, Wen; Policastro, Gina M; Hua, Geng; Guo, Kai; Zhou, Jinjun; Wesdemiotis, Chrys; Doll, Gary L; Becker, Matthew L

    2014-11-19

    A series of multivalent dendrons containing a bioactive osteogenic growth peptide (OGP) domain and surface-binding catechol domains were obtained through solid phase synthesis, and their binding affinity to hydroxyapatite, TiO2, ZrO2, CeO2, Fe3O4 and gold was characterized using a quartz crystal microbalance with dissipation (QCM-d). Using the distinct difference in binding affinity of the bioconjugate to the metal oxides, TiO2-coated glass slides were selectively patterned with bioactive peptides. Cell culture studies demonstrated the bioavailability of the OGP and that OGP remained on the surface for at least 2 weeks under in vitro cell culture conditions. Bone sialoprotein (BSP) and osteocalcein (OCN) markers were upregulated 3-fold and 60-fold, respectively, relative to controls at 21 days. Similarly, 3-fold more calcium was deposited using the OGP tethered dendron compared to TiO2. These catechol-bearing dendrons provide a fast and efficient method to functionalize a wide range of inorganic materials with bioactive peptides and have the potential to be used in coating orthopaedic implants and fixation devices. PMID:25343707

  10. Linking electrostatic effects and protein motions in enzymatic catalysis. A theoretical analysis of catechol o-methyltransferase.

    PubMed

    García-Meseguer, Rafael; Zinovjev, Kirill; Roca, Maite; Ruiz-Pernía, Javier J; Tuñón, Iñaki

    2015-01-22

    The role of protein motions in enzymatic catalysis is the subject of a hot scientific debate. We here propose the use of an explicit solvent coordinate to analyze the impact of environmental motions during the reaction process. The example analyzed here is the reaction catalyzed by catechol O-methyltransferase, a methyl transfer reaction from S-adenosylmethionine (SAM) to the nucleophilic oxygen atom of catecholate. This reaction proceeds from a charged reactant to a neutral product, and then a large electrostatic coupling with the environment could be expected. By means of a two-dimensional free energy surface, we show that a large fraction of the environmental motions needed to attain the transition state happens during the first stages of the reaction because most of the environmental motions are slower than changes in the substrate. The incorporation of the solvent coordinate in the definition of the transition state improves the transmission coefficient and the committor histogram in solution, while the changes are much less significant in the enzyme. The equilibrium solvation approach seems then to work better in the enzyme than in aqueous solution because the enzyme provides a preorganized environment where the reaction takes place. PMID:25159911

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

    NASA Astrophysics Data System (ADS)

    Liu, Yujie; Luo, Rifang; Shen, Fangyu; Tang, Linlin; Wang, Jin; Huang, Nan

    2015-02-01

    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.

  12. Rice OsFLS2-Mediated Perception of Bacterial Flagellins Is Evaded by Xanthomonas oryzae pvs. oryzae and oryzicola.

    PubMed

    Wang, Shanzhi; Sun, Zhe; Wang, Huiqin; Liu, Lijuan; Lu, Fen; Yang, Jun; Zhang, Min; Zhang, Shiyong; Guo, Zejian; Bent, Andrew F; Sun, Wenxian

    2015-07-01

    Bacterial flagellins are often recognized by the receptor kinase FLAGELLIN SENSITIVE2 (FLS2) and activate MAMP-triggered immunity in dicotyledonous plants. However, the capacity of monocotyledonous rice to recognize flagellins of key rice pathogens and its biological relevance remain poorly understood. We demonstrate that ectopically expressed OsFLS2 in Arabidopsis senses the eliciting flg22 peptide and in vitro purified Acidovorax avenae (Aa) flagellin in an expression level-dependent manner, but does not recognize purified flagellins or derivative flg22(Xo) peptides of Xanthomonas oryzae pvs. oryzae (Xoo) and oryzicola (Xoc). Consistently, the flg22 peptide and purified Aa flagellin, but not Xoo/Xoc flagellins, induce various immune responses such as defense gene induction and MAPK activation in rice. Perception of flagellin by rice does induce strong resistance to Xoo infection, as shown after pre-treatment of rice leaves with Aa flagellin. OsFLS2 was found to differ from AtFLS2 in its perception specificities or sensitivities to different flg22 sequences. In addition, post-translational modification of Xoc flagellin was altered by deletion of glycosyltransferase-encoding rbfC, but this had little effect on Xoc motility and rpfC mutation did not detectably reduce Xoc virulence on rice. Deletion of flagellin-encoding fliC from Xoo/Xoc blocked swimming motility but also did not significantly alter Xoo/Xoc virulence. These results suggest that Xoo/Xoc carry flg22-region amino acid changes that allow motility while evading the ancient flagellin detection system in rice, which retains recognition capacity for other bacterial pathogens. PMID:25617720

  13. Covalently bound phosphate residues in bovine milk xanthine oxidase and in glucose oxidase from Aspergillus niger: A reevaluation

    SciTech Connect

    Johnson, J.L.; Rajagopalan, K.V. (Duke Univ. Medical Center, Durham, NC (USA)); London, R.E. (National Institute of Environmental Health Science, Research Triangle Park, NC (USA))

    1989-09-01

    The reported presence of covalently bound phosphate residues in flavoproteins has significant implications with regard to the catalytic mechanisms and structural stability of the specific enzymes themselves and in terms of general cellular metabolic regulation. These considerations have led to a reevaluation of the presence of covalently bound phosphorus in the flavoproteins xanthine oxidase and glucose oxidase. Milk xanthine oxidase purified by a procedure that includes anion-exchange chromatography is shown to contain three phosphate residues. All three are noncovalently associated with the protein, two with the FAD cofactor, and one with the molybdenum cofactor. Results of chemical analysis and {sup 31}P NMR spectroscopy indicate that enzyme purified by this method contains no phosphoserine residues. Xanthine oxidase preparations purified by chromatography on calcium phosphate gel in place of DEAE-Sephadex yielded higher phosphate-to-protein ratios, which could be reduced to the expected values by additional purification on a folate affinity column. Highly active, highly purified preparations of glucose oxidase are shown to contain only the two phosphate residues of the FAD cofactor. The covalently bound bridging phosphate reported by others may arise in aged or degraded preparations of the enzyme but appears not to be a constituent of functional glucose oxidase. These results suggest that the presence of covalent phosphate residues in other flavoproteins should be rigorously reevaluated as well.

  14. Monoamine oxidase inactivation: from pathophysiology to therapeutics

    PubMed Central

    Bortolato, Marco; Chen, Kevin; Shih, Jean C

    2008-01-01

    Monoamine oxidases (MAOs) A and B are mitochondrial bound isoenzymes which catalyze the oxidative deamination of dietary amines and monoamine neurotransmitters, such as serotonin, norepinephrine, dopamine, ?-phenylethylamine and other trace amines. The rapid degradation of these molecules ensures the proper functioning of synaptic neurotransmission and is critically important for the regulation of emotional behaviors and other brain functions. The byproducts of MAO-mediated reactions include several chemical species with neurotoxic potential, such as hydrogen peroxide, ammonia and aldehydes. As a consequence, it is widely speculated that prolonged excessive activity of these enzymes may be conducive to mitochondrial damages and neurodegenerative disturbances. In keeping with these premises, the development of MAO inhibitors has led to important breakthroughs in the therapy of several neuropsychiatric disorders, ranging from mood disorders to Parkinson’s disease. Furthermore, the characterization of MAO knockout (KO) mice has revealed that the inactivation of this enzyme produces a number of functional and behavioral alterations, some of which may be harnessed for therapeutic aims. In this article, we discuss the intriguing hypothesis that the attenuation of the oxidative stress induced by the inactivation of either MAO isoform may contribute to both antidepressant and antiparkinsonian actions of MAO inhibitors. This possibility further highlights MAO inactivation as a rich source of novel avenues in the treatment of mental disorders. PMID:18652859

  15. Monoamine oxidase: Radiotracer chemistry and human studies

    DOE PAGESBeta

    Fowler, Joanna S.; Logan, Jean; Shumay, Elena; Alia-Klein, Nelly; Wang, Gene-Jack; Volkow, Nora D.

    2015-03-01

    Monoamine oxidase (MAO) oxidizes amines from both endogenous and exogenous sources thereby regulating the concentration of neurotransmitter amines such as serot onin, norepinephrine and dopamine as well as many xenobiotics. MAO inhibitor drugs are used in the treatment of Parkinson’s disease and in depression stimulating the development of radiotracer tools to probe the role of MAO in normal human biology and in disease. Over the past 30 since the first radiotracers were developed and the first PET images of MAO in humans were carried out, PET studies of brain MAO in healthy volunteers and in patients have identified different variablesmore »which have contributed to different MAO levels in brain and in peripheral organs. MAO radiotracers and PET have also been used to study the current and developing MAO inhibitor drugs including the selection of doses for clinical trials. In this article, we describe (1) the development of MAO radiotracers; (2) human studies including the relationship of brain MAO levels to genotype, personality, neurological and psychiatric disorders; (3) examples of the use of MAO radiotracers in drug research and development. We will conclude with outstanding needs to improve the radiotracers which are currently used and possible new applications.« less

  16. Crystallization of beef heart cytochrome c oxidase

    NASA Astrophysics Data System (ADS)

    Yoshikawa, Shinya; Shinzawa, Kyoko; Tsukihara, Tomitake; Abe, Toshio; Caughey, Winslow S.

    1991-03-01

    The three-dimensional structure of cytochrome c oxidase, a complex (multimetal, multisubunit) membrane protein is critical to elucidation of the mechanism of the enzymic reactions and their control. Our recent developments in the crystallization of the enzyme isolated from beef hearts are presented. The crystals appeared more readily at higher protein concentration, lower ionic strength, higher detergent concentration (Brij-35) and lower temperature. Large crystals were obtained by changing one of these parameters to the crystallization point as slowly as possible, keeping the other parameters constant. Increasing the detergent concentration was the most successful method, producing green crystals of the resting oxidized form as hexagonal bipyramids with typical dimensions of 0.6 mm. The usual procedures for crystallization of water soluble proteins, such as increasing ionic strength by vapor diffusion, were not applicable for this enzyme. Crystals of the resting oxidized enzyme belong to a space group of P6 2 or P6 4 with cell dimensions, a = b = 208.7 Å and c = 282.3 Å. The Patterson function shows that the crystal exhibited a non-crystallographic two-fold axis parallel to the c-axis in the asymmetric unit.

  17. Monoamine oxidase: Radiotracer chemistry and human studies

    DOE PAGESBeta

    Fowler, Joanna S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Logan, Jean [New York Univ., Langone Medical Center, New York, NY (United States); Shumay, Elena [National Inst. on Alcohol Abuse and Alcoholism, National Inst. of Health, Betheseda, MD (United States); Alia-Klein, Nelly [Mount Sinai School of Medicine, New York, NY (United States); Wang, Gene-Jack [National Inst. on Alcohol Abuse and Alcoholism, National Inst. of Health, Betheseda, MD (United States); Volkow, Nora D. [National Inst. on Alcohol Abuse and Alcoholism, National Inst. of Health, Betheseda, MD (United States); National Inst. on Drug Abuse, National Inst. of Health, Bethesda, MD (United States)

    2015-03-01

    Monoamine oxidase (MAO) oxidizes amines from both endogenous and exogenous sources thereby regulating the concentration of neurotransmitter amines such as serot onin, norepinephrine and dopamine as well as many xenobiotics. MAO inhibitor drugs are used in the treatment of Parkinson’s disease and in depression stimulating the development of radiotracer tools to probe the role of MAO in normal human biology and in disease. Over the past 30 since the first radiotracers were developed and the first PET images of MAO in humans were carried out, PET studies of brain MAO in healthy volunteers and in patients have identified different variables which have contributed to different MAO levels in brain and in peripheral organs. MAO radiotracers and PET have also been used to study the current and developing MAO inhibitor drugs including the selection of doses for clinical trials. In this article, we describe (1) the development of MAO radiotracers; (2) human studies including the relationship of brain MAO levels to genotype, personality, neurological and psychiatric disorders; (3) examples of the use of MAO radiotracers in drug research and development. We will conclude with outstanding needs to improve the radiotracers which are currently used and possible new applications.

  18. Origin and evolution of lysyl oxidases

    PubMed Central

    Grau-Bové, Xavier; Ruiz-Trillo, Iñaki; Rodriguez-Pascual, Fernando

    2015-01-01

    Lysyl oxidases (LOX) are copper-dependent enzymes that oxidize primary amine substrates to reactive aldehydes. The best-studied role of LOX enzymes is the remodeling of the extracellular matrix (ECM) in animals by cross-linking collagens and elastin, although intracellular functions have been reported as well. Five different LOX enzymes have been identified in mammals, LOX and LOX-like (LOXL) 1 to 4, showing a highly conserved catalytic carboxy terminal domain and more divergence in the rest of the sequence. Here we have surveyed a wide selection of genomes in order to infer the evolutionary history of LOX. We identified LOX proteins not only in animals, but also in many other eukaryotes, as well as in bacteria and archaea – which reveals a pre-metazoan origin for this gene family. LOX genes expanded during metazoan evolution resulting in two superfamilies, LOXL2/L3/L4 and LOX/L1/L5. Considering the current knowledge on the function of mammalian LOX isoforms in ECM remodeling, we propose that LOXL2/L3/L4 members might have preferentially been involved in making cross-linked collagen IV-based basement membrane, whereas the diversification of LOX/L1/L5 forms contributed to chordate/vertebrate-specific ECM innovations, such as elastin and fibronectin. Our work provides a novel view on the evolution of this family of enzymes. PMID:26024311

  19. Origin and evolution of lysyl oxidases.

    PubMed

    Grau-Bové, Xavier; Ruiz-Trillo, Iñaki; Rodriguez-Pascual, Fernando

    2015-01-01

    Lysyl oxidases (LOX) are copper-dependent enzymes that oxidize primary amine substrates to reactive aldehydes. The best-studied role of LOX enzymes is the remodeling of the extracellular matrix (ECM) in animals by cross-linking collagens and elastin, although intracellular functions have been reported as well. Five different LOX enzymes have been identified in mammals, LOX and LOX-like (LOXL) 1 to 4, showing a highly conserved catalytic carboxy terminal domain and more divergence in the rest of the sequence. Here we have surveyed a wide selection of genomes in order to infer the evolutionary history of LOX. We identified LOX proteins not only in animals, but also in many other eukaryotes, as well as in bacteria and archaea - which reveals a pre-metazoan origin for this gene family. LOX genes expanded during metazoan evolution resulting in two superfamilies, LOXL2/L3/L4 and LOX/L1/L5. Considering the current knowledge on the function of mammalian LOX isoforms in ECM remodeling, we propose that LOXL2/L3/L4 members might have preferentially been involved in making cross-linked collagen IV-based basement membrane, whereas the diversification of LOX/L1/L5 forms contributed to chordate/vertebrate-specific ECM innovations, such as elastin and fibronectin. Our work provides a novel view on the evolution of this family of enzymes. PMID:26024311

  20. Xanthine oxidase inhibitory lanostanoids from Ganoderma tsugae.

    PubMed

    Lin, Kai-Wei; Chen, Yen-Ting; Yang, Shyh-Chyun; Wei, Bai-Luh; Hung, Chi-Feng; Lin, Chun-Nan

    2013-09-01

    Two new lanostanoids, 3?-acetoxy-22-oxo-5?-lanosta-8,24-dien-21-oic acid, named tsugaric acid D (1) and 16?-hydroxy-3-oxo-5?-lanosta-6,8,24(24(1))-trien-21-oic acid, named tsugaric acid E (2) were isolated from the fruit bodies of Ganoderma tsugae. The structures 1 and 2 were determined by spectroscopic methods. Compound 1 and known compounds 3 and 6 exhibited significant inhibitory effects on xanthine oxidase (XO) activity with an IC50 values of 90.2±24.2, 116.1±3.0, and 181.9±5.8 ?M, respectively. Known compound 5 was able to protect human keratinocytes against damage induced by UVB light, which showed 5 could protect keratinocytes from photodamage. The 1 and 5 ?M 1 combined with 5 ?M cisplatin, respectively, enhanced the cytotoxicity induced by cisplatin. It suggested that 1 and 5 ?M 1 combined with low dose of cisplatin may enhance the therapeutic efficacy of cisplatin and reduce side effect and cisplatin resistant. PMID:23769935

  1. Conversion of Escherichia coli pyruvate oxidase to an 'alpha-ketobutyrate oxidase'.

    PubMed Central

    Chang, Y Y; Cronan, J E

    2000-01-01

    Escherichia coli pyruvate oxidase (PoxB), a lipid-activated homotetrameric enzyme, is active on both pyruvate and 2-oxobutanoate ('alpha-ketobutyrate'), although pyruvate is the favoured substrate. By localized random mutagenesis of residues chosen on the basis of a modelled active site, we obtained several PoxB enzymes that had a markedly decreased activity with the natural substrate, pyruvate, but retained full activity with 2-oxobutanoate. In each of these mutant proteins Val-380 had been replaced with a smaller residue, namely alanine, glycine or serine. One of these, PoxB V380A/L253F, was shown to lack detectable pyruvate oxidase activity in vivo; this protein was purified, studied and found to have a 6-fold increase in K(m) for pyruvate and a 10-fold lower V(max) with this substrate. In contrast, the mutant had essentially normal kinetic constants with 2-oxobutanoate. The altered substrate specificity was reflected in a decreased rate of pyruvate binding to the latent conformer of the mutant protein owing to the V380A mutation. The L253F mutation alone had no effect on PoxB activity, although it increased the activity of proteins carrying substitutions at residue 380, as it did that of the wild-type protein. The properties of the V380A/L253F protein provide new insights into the mode of substrate binding and the unusual activation properties of this enzyme. PMID:11104678

  2. Hot electron-induced cathodic electrochemiluminescence at oil film-covered carbon paste electrode and application to nano-molar determination of catechol.

    PubMed

    Chen, Xiao-Yan; Zheng, Rui-Juan; Qin, Su-Fang; Sun, Jian-Jun

    2012-11-15

    Hot electron-induced cathodic electrochemiluminescence of the Ru(bpy)(3)(2+)/S(2)O(8)(2-) system was investigated at an oil film-covered carbon paste electrode (CPE) under cathodic pulse polarization for the first time. Compared with other electrodes, the CPE is of lower background, better stability and reproducibility. The method is also applied to the determination of catechol. Under the optimum conditions, the linear correlation between the quenched ECL intensity (?I) and the logarithm of catechol concentration (logC(catechol)) was observed over the range of 2.0×10(-10) mol/L-4.0×10(-9) mol/L and 4.0×10(-9) mol/L-4.0×10(-7) mol/L with the limit of detection (LOD) of 2.0×10(-10) mol/L, which is lower than the other reported methods. The proposed method is applied to determine catechol in reservoir water. The mean recoveries of 83.3%-99.0% and the relative standard deviations (RSDs) of 0.8%-2.2% were obtained. PMID:23158335

  3. Metabolism of benzoic acid by bacteria: 3,5-cyclohexadiene-1,2-diol-1-carboxylic acid is an intermediate in the formation of catechol.

    PubMed

    Reiner, A M

    1971-10-01

    3,5-Cyclohexadiene-1,2-diol-1-carboxylic acid (1,2-dihydro-1,2-dihydroxy-benzoic acid) is converted enzymatically to catechol in cell extracts from Acinetobacter, Alcaligenes, Azotobacter, and three Pseudomonas species. This enzymatic activity is present only in cultures which have been grown in the presence of benzoic acid, and which convert benzoic acid to catechol rather than to protocatechuic acid. The reaction is assayed by the concomitant formation of reduced nicotinamide adenine dinucleotide from nicotinamide adenine dinucleotide. The conversion of [(14)C]benzoic acid to [(14)C]dihydrodihydroxybenzoic acid is demonstrated in cell extracts. A scheme for the conversion of benzoic acid to catechol in bacteria is presented, involving the formation of dihydrodihydroxybenzoic acid from benzoic acid by a dioxygenase which is unstable in cell extracts, followed by the dehydrogenation and decarboxylation of dihydrodihydroxybenzoic acid to catechol by a previously undescribed enzyme. Experiments with anthranilic acid and phthalic acid suggest that dihydrodihydroxybenzoic acid is a metabolite unique to benzoic acid metabolism. Two new methods for assaying benzoic acid dioxygenase are suggested. PMID:4399343

  4. MAPPING QUANTITATVE TRAIT LOCI FOR YIELD, YIELD COMPONENTS AND MORPHOLOGICAL TRAITS IN AN ADVANCED BACKCROSS POPULATION BETWEEN ORYZA RUFIPOGON AND THE ORYZA SATIVA CULTIVAR JEFFERSON

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A BC2F2 population developed from an interspecific cross between IR64 (Oryza sativa) and O. rufipogon (IRGC 105491) was used in an advanced backcross QTL analysis to identify and introduce agronomically useful genes from this wild relative into the cultivated gene pool. Two hundred eighty five famil...

  5. Natural variation of the rice blast resistance gene Pi-ta in Oryza species and its corresponding avirulence gene AVR-Pita in Magnaporthe oryzae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Pi-ta gene prevents the infections of M. oryzae races containing the corresponding avirulence gene AVR-Pita in a gene-for-gene manner. Pi-ta is a putative NBS type major resistance gene, and can directly recognize the AVR-Pita putative metalloprotease in triggering effective resistance. We hav...

  6. L-lactic acid production from starch by simultaneous saccharification and fermentation in a genetically engineered Aspergillus oryzae pure culture.

    PubMed

    Wakai, Satoshi; Yoshie, Toshihide; Asai-Nakashima, Nanami; Yamada, Ryosuke; Ogino, Chiaki; Tsutsumi, Hiroko; Hata, Yoji; Kondo, Akihiko

    2014-12-01

    Lactic acid is a commodity chemical that can be produced biologically. Lactic acid-producing Aspergillus oryzae strains were constructed by genetic engineering. The A. oryzae LDH strain with the bovine L-lactate dehydrogenase gene produced 38 g/L of lactate from 100g/L of glucose. Disruption of the wild-type lactate dehydrogenase gene in A. oryzae LDH improved lactate production. The resulting strain A. oryzae LDH?871 produced 49 g/L of lactate from 100g/L of glucose. Because A. oryzae strains innately secrete amylases, A. oryzae LDH?871 produced approximately 30 g/L of lactate from various starches, dextrin, or maltose (all at 100 g/L). To our knowledge, this is the first report describing the simultaneous saccharification and fermentation of lactate from starch using a pure culture of transgenic A. oryzae. Our results indicate that A. oryzae could be a promising host for the bioproduction of useful compounds such as lactic acid. PMID:25314668

  7. Characterizing virulence phenotypes among U.S. isolates of Magnaporthe oryzae using IRRI NILs, US germplasm, and NERICA lines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice blast disease, caused by Magnaporthe oryzae, is a major constraint to rice production in most rice production areas, including the Southern U.S. In continued efforts to evaluate the effectiveness of resistance (R) genes, a total of 33 field and 12 U.S. reference isolates of M. oryzae were eval...

  8. Southern U.S. weedy red rice(Oryza sativa) accessions for entry into the National Small Grains Collection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Red rice (Oryza sativa) is a troublesome weed in rice (Oryza sativa) production systems in the southern U.S. and throughout the world, especially where direct seeding methods are employed. Diverse biotypes of red rice infest rice in the southern U.S. This creates a challenge for management and con...

  9. Native and Modified Lactate Dehydrogenase Expression in a Fumaric Acid Producing isolate Rhizopus oryzae 99-880

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizopus oryzae is a filamentous fungus that is of broad importance to the industrial, agricultural, and medical community. R. oryzae can be subdivided into two groups based on genetic and phenotypic differences. Type-I isolates accumulate primarily lactic acid when grown in the presence of a ferm...

  10. Mapping two major resistance genes in an indica cultivar Zhe733 to the race IE-1K of Magnaporthe oryzae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Resistance (R) genes in rice confer resistance to races of Magnaporthe oryzae that contain the corresponding avirulence genes. The race IE-1K of M. oryzae recovered from the southern US overcomes R gene Pi-ta. The objectives of the present study were to identify new resistance sources to IE-1k an...

  11. Diversification and evolution of the avirulence gene AVR-Pita1 in field isolates of Magnaporthe oryzae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The study of the evolution of the AVR-Pita1 genes should benefit the deployment of the resistance gene Pi-ta for protecting rice production. The AVR-Pita1 avirulence gene in races of Magnaporthe oryzae triggers an effective resistance response when M. oryzae infects rice plants that contain the Pi-...

  12. Expression profiling of common and specific defense responses of rice to Magnaporthe oryzae infection using deep sequencing technologies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice blast caused by Magnaporthe oryzae is a serious disease in rice production. Wild type Nipponbare and transgenic rice plants (carrying the Pi9 blast resistance gene) were challenged with the rice blast strain KJ201 to identify the early, mid and late host responses to M. oryzae infection at the ...

  13. Genome-wide comparative analyses of domain organisation of repertoires of protein kinases of Arabidopsis thaliana and Oryza sativa

    E-print Network

    Srinivasan, N.

    of Arabidopsis thaliana and Oryza sativa A. Krupa 1,2 , Anamika 2 , N. Srinivasan Molecular Biophysics Unit, namely Arabidopsis thaliana and Oryza sativa spp japonica cv. Nipponbare is reported in the current study. We have analysed 836 and 1386 kinases identified from A. thaliana and the O. sativa genomes

  14. Preliminary assessment of resistance among U.S. wheat cultivars to the Triticum pathotype of Magnaporthe oryzae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Magnaporthe oryzae is the causal agent of blast disease on several graminaceous plants. The M. oryzae population causing wheat blast has not been officially reported outside South America. U.S. wheat production is at risk to this pathogen if it is introduced and established. Proactive testing of U.S...

  15. Differentiation in MALDI-TOF MS and FTIR spectra between two pathovars of Xanthomonas oryzae.

    PubMed

    Ge, Mengyu; Li, Bin; Wang, Li; Tao, Zhongyun; Mao, Shengfeng; Wang, Yangli; Xie, Guanlin; Sun, Guochang

    2014-12-10

    Xanthomonas oryzae pv. oryzae (Xoo) and Xanthomonas oryzae pv. oryzicola (Xoc) strains are closely related phenotypically and genetically, which make it difficult to differentiate between the two pathovars based on phenotypic and DNA-based methods. In this study, a fast and accurate method was developed based on the differences in MALDI-TOF MS and FTIR spectra between the two pathovars. MALDI-TOF MS analysis revealed that 9 and 10 peaks are specific to Xoo and Xoc, respectively, which can be used as biomarkers to identify and differentiate the two closely related pathovars. Furthermore, FTIR analysis showed that there is a significant difference in both the band frequencies and absorption intensity of various functional groups between the two pathovars. In particular, the 6 peaks at 3433, 2867, 1273, 1065, 983 and 951cm(-1) were specific to the Xoo strains, while one peak at 1572cm(-1) was specific to the Xoc strains. Overall, this study gives the first attempt to identify and differentiate the two pathovars of X. oryzae based on mass and FTIR spectra, which will be helpful for the early detection and prevention of the two rice diseases caused by both X. oryzae pathovars. PMID:24996215

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

    PubMed Central

    Jung, Moon Chul; Weber, Stephen G.

    2006-01-01

    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-?m-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)33+ by analyte to the photoluminescent Os(bpy)32+) 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-hydroquinone. Kinetically controlled reactions of catechols, however, could be also completed in a reasonable time at increased reagent concentration. A satisfactory reactor, operating at 1.7 cm/s (2 ?L/min) velocity with solutes having diffusion coefficients in the 5 × 10?6 cm2/s range, can be constructed from 8.0 cm of 25-?m-radius capillary. Slower reactions require longer reaction times, but theoretical calculations expect that a CTR does not broaden a chromatographic peak (N = 14 000) from a 100-?m-capillary chromatography column by 10% if the pseudo-first-order rate constant is larger than 0.1 s?1. PMID:15858975

  17. The alternative oxidases: simple oxidoreductase proteins with complex functions.

    PubMed

    Young, Luke; Shiba, Tomoo; Harada, Shigeharu; Kita, Kiyoshi; Albury, Mary S; Moore, Anthony L

    2013-10-01

    The alternative oxidases are membrane-bound monotopic terminal electron transport proteins found in all plants and in some agrochemically important fungi and parasites including Trypansoma brucei, which is the causative agent of trypanosomiasis. They are integral membrane proteins and reduce oxygen to water in a four electron process. The recent elucidation of the crystal structure of the trypanosomal alternative oxidase at 2.85 Å (1 Å=0.1 nm) has revealed salient structural features necessary for its function. In the present review we compare the primary and secondary ligation spheres of the alternative oxidases with other di-iron carboxylate proteins and propose a mechanism for the reduction of oxygen to water. PMID:24059524

  18. The mechanism of cytochrome C oxidase inhibition by nitric oxide.

    PubMed

    Antunes, Fernando; Cadenas, Enrique

    2007-01-01

    The basic biochemistry of the inhibition of cytochrome oxidase by NO is reviewed. Three possible mechanisms that include the binding of NO to the fully reduced Fe(a3)-Cu(B) site, to the semi-reduced Fe(a3)-Cu(B) site, and to the fully oxidized Fe(a3)-Cu(B) site are confronted with the experimental data. Mathematical models are used to facilitate the analysis and to solve puzzling observations concerning the NO inhibition of cytochrome oxidase. It is concluded that the inhibition of cytochrome oxidase by NO is mixed, having both competitive and uncompetitive components, but under physiological electron flows the competitive component is largely predominant. The physiological and pathological relevance of this inhibition is briefly discussed. PMID:17127353

  19. Characterization of wheat germin (oxalate oxidase) expressed by Pichia pastoris

    SciTech Connect

    Pan, Heng-Yen [Department of Environmental and Biomolecular Systems, Oregon Health and Sciences University, 20000 N.W. Walker Road, Beaverton, OR 97006-8921 (United States); Whittaker, Mei M. [Department of Environmental and Biomolecular Systems, Oregon Health and Sciences University, 20000 N.W. Walker Road, Beaverton, OR 97006-8921 (United States); Bouveret, Romaric [IBMP-Institut de Botanique, Strasbourg (France); Berna, Anne [IBMP-Institut de Botanique, Strasbourg (France); Bernier, Francois [IBMP-Institut de Botanique, Strasbourg (France); Whittaker, James W. [Department of Environmental and Biomolecular Systems, Oregon Health and Sciences University, 20000 N.W. Walker Road, Beaverton, OR 97006-8921 (United States)]. E-mail: jim@ebs.ogi.edu

    2007-05-18

    High-level secretory expression of wheat (Triticum aestivum) germin/oxalate oxidase was achieved in Pichia pastoris fermentation cultures as an {alpha}-mating factor signal peptide fusion, based on the native wheat cDNA coding sequence. The oxalate oxidase activity of the recombinant enzyme is substantially increased (7-fold) by treatment with sodium periodate, followed by ascorbate reduction. Using these methods, approximately 1 g (4 x 10{sup 4} U) of purified, activated enzyme was obtained following eight days of induction of a high density Pichia fermentation culture, demonstrating suitability for large-scale production of oxalate oxidase for biotechnological applications. Characterization of the recombinant protein shows that it is glycosylated, with N-linked glycan attached at Asn47. For potential biomedical applications, a nonglycosylated (S49A) variant was also prepared which retains essentially full enzyme activity, but exhibits altered protein-protein interactions.

  20. Clinical applications of L-lactate oxidase-based biosensor

    NASA Astrophysics Data System (ADS)

    Xing, Keli; Liu, Yanfan; Wang, Lei; Han, Qiao; Yin, Lizhi

    2001-09-01

    A L-lactate oxidase (LOD)-based biosensor is developed for the determination of L-lactate in blood samples. The L- lactate oxidase membrane is prepared by covalently linking LOD into a nylon set, followed by attaching the membrane onto a flow injection type of oxygen electrode. The response of the biosensor is based on the limited diffusion of L- lactate on the L-lactate oxidase membrane. No performance difference have been found between the LOD-based biosensor and regular enzyme optical determination methods for blood sample testing. It is suggested that the LOD-based biosensor may serve as an alternative for the detection of L-lactate in blood.

  1. X-ray absorption spectroscopy of chicken sulfite oxidase crystals

    SciTech Connect

    George, G.N.; Pickering, I.J. [Stanford Univ., CA (United States). Stanford Synchrotron Radiation Lab.] [Stanford Univ., CA (United States). Stanford Synchrotron Radiation Lab.; Kisker, C. [State Univ. of New York, Stony Brook, NY (United States). Dept. of Pharmacological Sciences] [State Univ. of New York, Stony Brook, NY (United States). Dept. of Pharmacological Sciences

    1999-05-17

    Sulfite oxidase catalyzes the physiologically vital oxidation of sulfite to sulfate. Recently, the crystal structure of chicken sulfite oxidase has been reported at 1.9 {angstrom} resolution. In contrast to the information available from previous X-ray absorption spectroscopic studies, the active site indicated by crystallography was a mono-oxo species. Because of this the possibility that the crystals did in fact contain a reduced molybdenum species was considered in the crystallographic work. The authors report herein an X-ray absorption spectroscopic study of polycrystalline sulfite oxidase prepared in the same manner as the previous single-crystal samples, and compare this with data for frozen solutions of oxidized and reduced enzyme.

  2. Perchlorate reduction using free and encapsulated Azospira oryzae enzymes.

    PubMed

    Hutchison, Justin M; Poust, Sean K; Kumar, Manish; Cropek, Donald M; Macallister, Irene E; Arnett, Clint M; Zilles, Julie L

    2013-09-01

    Existing methods for perchlorate remediation are hampered by the common co-occurrence of nitrate, which is structurally similar and a preferred electron acceptor. In this work, the potential for perchlorate removal using cell-free bacterial enzymes as biocatalysts was investigated using crude cell lysates and soluble protein fractions of Azospira oryzae PS, as well as soluble protein fractions encapsulated in lipid and polymer vesicles. The crude lysates showed activities between 41?700 to 54?400 U L(-1) (2.49 to 3.06 U mg(-1) total protein). Soluble protein fractions had activities of 15?400 to 29?900 U L(-1) (1.70 to 1.97 U mg(-1)) and still retained an average of 58.2% of their original activity after 23 days of storage at 4 °C under aerobic conditions. Perchlorate was removed by the soluble protein fraction at higher rates than nitrate. Importantly, perchlorate reduction occurred even in the presence of 500-fold excess nitrate. The soluble protein fraction retained its function after encapsulation in lipid or polymer vesicles, with activities of 13.8 to 70.7 U L(-1), in agreement with theoretical calculations accounting for the volume limitation of the vesicles. Further, encapsulation mitigated enzyme inactivation by proteinase K. Enzyme-based technologies could prove effective at perchlorate removal from water cocontaminated with nitrate or sulfate. PMID:23924304

  3. Kinetic modeling of fructooligosaccharide production using Aspergillus oryzae N74.

    PubMed

    Guio, Felipe; Rugeles, Luz D; Rojas, Sonia E; Palomino, María P; Camargo, María C; Sánchez, Oscar F

    2012-05-01

    In this study, the kinetic for the bioconversion of sucrose to fructooligosaccharides (FOS) by free cells of Aspergillus oryzae N74 was modeled. In addition, the effect of immobilized glucose isomerase (IGI) on FOS production yield was evaluated and considered in the kinetic model. The selected kinetic models were based on a proposed reaction mechanism described by elementary rate equations and modified Michaelis-Menten kinetic equations. The use of IGI allowed to increase the FOS production yield (FOS(Yield)) and to decrease the glucose/fructose (G/F) ratio. At shake flask scale, the FOS(Yield) was increased in 4.7 % (final yield 58.3 %), while the G/F ratio was reduced 6.2-fold. At bench scale, the FOS(Yield) was increased in 2.2 % (final yield 57.3 %), while the G/F ratio was reduced 4.5-fold. The elementary rate equation model was the one that best adjusted experimental data for FOS production using either the fungus biomass or the mixture fungus biomass-IGI, with an overall average percentage error of 7.2. Despite that FOS production yield was not highly improved by the presence of IGI in the reaction mixture, it favored the reduction of residual glucose in the mixture, avoiding the loss of material owe to glucose transformation to fructose that can be used in situ for FOS production by the fructosyltransferase. PMID:22528647

  4. The Population Structure of African Cultivated Rice Oryza glaberrima (Steud.)

    PubMed Central

    Semon, Mande; Nielsen, Rasmus; Jones, Monty P.; McCouch, Susan R.

    2005-01-01

    Genome-wide linkage disequilibrium (LD) was investigated for 198 accessions of Oryza glaberrima using 93 nuclear microsatellite markers. Significantly elevated levels of LD were detected, even among distantly located markers. Free recombination among loci at the population genetic level was shown (1) by a lack of decay in LD among markers on the same chromosome and (2) by a strictly increasing composite likelihood function for the recombination parameter. This suggested that the elevation in LD was due not to physical linkage but to other factors, such as population structure. A Bayesian clustering analysis confirmed this hypothesis, indicating that the sample of O. glaberrima in this study was subdivided into at least five cryptic subpopulations. Two of these subpopulations clustered with control samples of O. sativa, subspecies indica and japonica, indicating that some O. glaberrima accessions represent admixtures. The remaining three O. glaberrima subpopulations were significantly associated with specific combinations of phenotypic traits—possibly reflecting ecological adaptation to different growing environments. PMID:15545652

  5. Characterization of a novel lipolytic enzyme from Aspergillus oryzae.

    PubMed

    Koseki, Takuya; Asai, Shungo; Saito, Natsumi; Mori, Masayo; Sakaguchi, Yasuko; Ikeda, Kazutaka; Shiono, Yoshihito

    2013-06-01

    In this study, we report the characterization of a protein from Aspergillus oryzae, exhibiting sequence identity with paraben esterase from the genus Aspergillus. The coding region of 1,586 bp, including a 77-bp intron, encoded a protein of 502 amino acids. The gene without the signal peptide of 19 amino acids was cloned into a vector, pPICZ?C, and expressed successfully in Pichia pastoris as an active extracellular protein. The purified recombinant protein had pH and temperature optima of 7.0-8.0 and 30 °C, respectively, and was stable at the pH range of 7.0-10.0 and up to 40 °C. The optimal substrate for hydrolysis by the purified recombinant protein, among a panel of ?-naphthyl esters (C2-C16), was ?-naphthyl butyrate (C4), with activity of 0.16 units/mg protein. The considerable hydrolytic activity of the purified recombinant enzyme toward tributyrin was determined. However, no paraben esterase activity was detected toward the ethyl, propyl, and butyl esters of 4-hydroxybenzoic acid. In addition, no activity was detected toward the methyl esters of ferulic, p-coumaric, caffeic, and sinapic acids that would indicate feruloyl esterase activity. PMID:23001008

  6. Proteomics study of silver nanoparticles toxicity on Oryza sativa L.

    PubMed

    Mirzajani, Fateme; Askari, Hossein; Hamzelou, Sara; Schober, Yvonne; Römpp, Andreas; Ghassempour, Alireza; Spengler, Bernhard

    2014-10-01

    The increasing use of silver nanoparticles, (AgNPs), will inevitably result in their release into the environment and thereby cause the exposure to plants. It was claimed that using AgNPs is a safe and efficient method to preserve and treat agents of disease in agriculture. This study tries to understand the protein populations and sub-populations and follow up environmental AgNPs stresses. To accomplish these, the action of homemade spherical AgNPs colloidal suspension against Oryza sativa L. was investigated by a proteomic approach (2-DE and NanoLC/FT-ICR MS identification). Twenty-eight responsive (decrement/increment in abundance) proteins were identified. Proteomic results revealed that an exposure of O. sativa L., root with different concentrations of AgNPs resulted in an accumulation of protein precursors, indicative of the dissipation of a proton motive force. The identified proteins are involved in oxidative stress tolerance, Ca(2+) regulation and signaling, transcription and protein degradation, cell wall and DNA/RNA/protein direct damage, cell division and apoptosis. The expression pattern of these proteins and their possible involvement in the nontoxicity mechanisms were discussed. PMID:25124680

  7. Synthesis and characterization of chromium(III) Schiff base complexes: antimicrobial activity and its electrocatalytic sensing ability of catechol.

    PubMed

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

    2015-03-15

    A series of acyclic Schiff base chromium(III) complexes were synthesized with the aid of microwave irradiation method. The complexes were characterized on the basis of elemental analysis, spectral analysis such as UV-Visible, Fourier transform infrared (FT-IR), nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR) spectroscopies and electrospray ionization (ESI) mass spectrometry. Electrochemical analysis of the complexes indicates the presence of chromium ion in +3 oxidation state. Cr (III) ion is stabilized by the tetradentate Schiff base ligand through its nitrogen and phenolic oxygen. From the spectral studies it is understood that the synthesized chromium(III) complexes exhibits octahedral geometry. Antimicrobial activity of chromium complexes was investigated towards the Gram positive and Gram negative bacteria. In the present work, an attempt was made to fabricate a new kind of modified electrode based on chromium Schiff base complexes for the detection of catechol at nanomolar level. PMID:25576940

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  9. Reversible swelling-shrinking behavior of hydrogen-bonded free-standing thin film stabilized by catechol reaction.

    PubMed

    Sun, Jiaxing; Su, Chao; Zhang, Xuejian; Yin, Wenjing; Xu, Jian; Yang, Shuguang

    2015-05-12

    Dopamine-modified poly(acrylic acid) (PAA-dopa) and poly(vinylpyrrolidone) (PVPON) was layer-by-layer (LbL) assembled to prepare thin film based on hydrogen bonding. The carboxylic group of acrylic acid and the phenolic hydroxyl group of dopamine can both act as hydrogen bond donors. The critical assembly and the critical disintegration pH values of PVPON/PAA-dopa film are enhanced compared with PVPON/PAA film. The hydrogen-bonded PVPON/PAA-dopa thin film can be cross-linked via catechol chemistry of dopamine. After cross-linking, the film can be exfoliated from the substrate in alkaline solution to get a free-standing film. Moreover, by tuning the pH value, deprotonation and protonation of PAA will make the hydrogen bond in the film break and reconstruct, which induces that the free-standing film has a reversible swelling-shrinking behavior. PMID:25899235

  10. Expression of Dm-AMP1 in rice confers resistance to Magnaporthe oryzae and Rhizoctonia solani.

    PubMed

    Jha, Sanjay; Tank, Harsukh G; Prasad, Bishun Deo; Chattoo, Bharat B

    2009-02-01

    Magnaporthe oryzae and Rhizoctonia solani, are among the most important pathogens of rice, severely limiting its productivity. Dm-AMP1, an antifungal plant defensin from Dahlia merckii, was expressed in rice (Oryza sativa L. sp. indica cv. Pusa basmati 1) using Agrobacterium tumefaciens-mediated transformation. Expression levels of Dm-AMP1 ranged from 0.43% to 0.57% of total soluble protein in transgenic plants. It was observed that constitutive expression of Dm-AMP1 suppresses the growth of M. oryzae and R. solani by 84% and 72%, respectively. Transgenic expression of Dm-AMP1 was not accompanied by an induction of pathogenesis-related (PR) gene expression, indicating that the expression of DmAMP1 directly inhibits the pathogen. The results of in vitro, in planta and microscopic analyses suggest that Dm-AMP1 expression has the potential to provide broad-spectrum disease resistance in rice. PMID:18618285

  11. Morphological and molecular characterization of Magnaporthe oryzae (fungus) from infected rice leaf samples

    NASA Astrophysics Data System (ADS)

    Muni, Nurulhidayah Mat; Nadarajah, Kalaivani

    2014-09-01

    Magnaporthe oryzae is a plant-pathogenic fungus that causes a serious disease affecting rice called rice blast. Outbreaks of rice blast have been a threat to the global production of rice. This fungal disease is estimated to cause production losses of US55 million each year in South and Southeast Asia. It has been used as a primary model for elucidating various aspects of the host-pathogen interaction with its host. We have isolated five isolates of Magnaporthe oryzae from diseased leaf samples obtained from the field at Kompleks Latihan MADA, Kedah, Malaysia. We have identified the isolates using morphological and microscopic studies on the fungal spores and the lesions on the diseased leaves. Amplification of the internal transcribed spacer (ITS) was carried out with universal primers ITS1 and ITS4. The sequence of each isolates showed at least 99% nucleotide identity with the corresponding sequence in GenBank for Magnaporthe oryzae.

  12. Triterpenoid glycosides from Medicago sativa as antifungal agents against Pyricularia oryzae.

    PubMed

    Abbruscato, Pamela; Tosi, Solveig; Crispino, Laura; Biazzi, Elisa; Menin, Barbara; Picco, Anna M; Pecetti, Luciano; Avato, Pinarosa; Tava, Aldo

    2014-11-19

    The antifungal properties of saponin mixtures from alfalfa (Medicago sativa L.) tops and roots, the corresponding mixtures of prosapogenins from tops, and purified saponins and sapogenins against the causal agent of rice blast Pyricularia oryzae isolates are presented. In vitro experiments highlighted a range of activities, depending upon the assayed metabolite. The antifungal effects of the most promising prosapogenin mixture from alfalfa tops were confirmed by means of in planta tests using three different Italian cultivars of rice (Oryza sativa L. ssp. japonica), known to possess high, medium, and low blast resistance. The evidenced antifungal properties of the tested metabolites allowed some considerations on their structure-activity relationship. Results indicate that prosapogenins are active compounds to prevent the fungal attack of P. oryzae on different rice cultivars. Therefore, if properly formulated, these substances could represent a promising and environmentally friendly treatment to control rice blast. PMID:25361378

  13. The genome sequence of African rice (Oryza glaberrima) and evidence for independent domestication.

    PubMed

    Wang, Muhua; Yu, Yeisoo; Haberer, Georg; Marri, Pradeep Reddy; Fan, Chuanzhu; Goicoechea, Jose Luis; Zuccolo, Andrea; Song, Xiang; Kudrna, Dave; Ammiraju, Jetty S S; Cossu, Rosa Maria; Maldonado, Carlos; Chen, Jinfeng; Lee, Seunghee; Sisneros, Nick; de Baynast, Kristi; Golser, Wolfgang; Wissotski, Marina; Kim, Woojin; Sanchez, Paul; Ndjiondjop, Marie-Noelle; Sanni, Kayode; Long, Manyuan; Carney, Judith; Panaud, Olivier; Wicker, Thomas; Machado, Carlos A; Chen, Mingsheng; Mayer, Klaus F X; Rounsley, Steve; Wing, Rod A

    2014-09-01

    The cultivation of rice in Africa dates back more than 3,000 years. Interestingly, African rice is not of the same origin as Asian rice (Oryza sativa L.) but rather is an entirely different species (i.e., Oryza glaberrima Steud.). Here we present a high-quality assembly and annotation of the O. glaberrima genome and detailed analyses of its evolutionary history of domestication and selection. Population genomics analyses of 20 O. glaberrima and 94 Oryza barthii accessions support the hypothesis that O. glaberrima was domesticated in a single region along the Niger river as opposed to noncentric domestication events across Africa. We detected evidence for artificial selection at a genome-wide scale, as well as with a set of O. glaberrima genes orthologous to O. sativa genes that are known to be associated with domestication, thus indicating convergent yet independent selection of a common set of genes during two geographically and culturally distinct domestication processes. PMID:25064006

  14. First case of Tritirachium oryzae as agent of onychomycosis and its susceptibility to antifungal drugs.

    PubMed

    Naseri, Ali; Fata, Abdolmajid; Najafzadeh, Mohammad Javad

    2013-08-01

    The first case of Tritirachium oryzae isolated from an Iranian patient is reported. A 44-year-old woman with a lesion in her fingernail was examined for onychomycosis. Direct microscopic examination of the nail clippings revealed fungal filaments and inoculation of portions of the nail clippings on cultures media yielded T. oryzae after 8 days. The isolate was identified as Tritirachium spp. on the basis of gross morphological characteristics of the fungal colony and microscopic characterization of slide cultures. The diagnosis of T. oryzae was confirmed by PCR sequencing of the internal transcribed spacer domain of the rDNA gene. In vitro antifungal susceptibility test demonstrated that the fungus was susceptible to itraconazole and posaconazole. The patient was treated with oral itraconazole. PMID:23591624

  15. Update: Mammalian Cytochrome c Oxidase, a Molecular Monster Subdued

    NSDL National Science Digital Library

    Shelagh Ferguson-Miller (Michigan State University; Department of Biochemistry)

    1996-05-24

    Access to the article is free, however registration and sign-in are required. The high-resolution crystal structure of mammalian cytochrome c oxidase, a key enzyme in aerobic metabolism, was recently reported in Science by Tsukihara et al. (1), and discussed in an accompanying Perspective (2). The original paper (1), a landmark achievement in protein structure analysis, described the structure of the six metal centers (two hemes, two copper centers, Mg, and Zn), information critical to understanding the energy-transforming activity of the enzyme. In this issue, Tsukihara et al. (3) now present the complete structure of bovine cytochrome c oxidase at name 2.8 resolution.

  16. Galactose oxidase in stereospecific oxidation of primary alcohols 

    E-print Network

    Root, Robert Lee

    1985-01-01

    (23) with the loss of a superoxide radical which then immediately HN g~N Hs OH I ?, C OH HP l H ( O OH H H~ Cg(fJ) N~~NH Figure 2. The current concept of the active site of galactose oxidase (18) . reoxidizes the Cu(I) to Cu... rate sufficient to account for the change in absorbance observed in the galactose oxidase reaction. Potassium ferricyanide also oxidizes o-dianisidine, the chromagen used in the assay, but again, at the concentrations used in the assay, the increase...

  17. The Arabidopsis acyl-CoA oxidase gene family.

    PubMed

    Eastmond, P J; Hooks, M; Graham, I A

    2000-12-01

    A family of acyl-CoA oxidase isozymes catalyse the first step in the peroxisomal fatty acid beta-oxidation spiral. Our group and others have recently characterized four genes from this family in the model oilseed Arabidopsis. These genes encode isozymes with different acyl-CoA substrate specificities, which together encompass the full range of fatty acid chain lengths that exist in vivo. Here we review the biochemical properties and physiological roles of the acyl-CoA oxidase isozymes. PMID:11171196

  18. A Conserved Steroid Binding Site in Cytochrome c Oxidase

    SciTech Connect

    Qin, Ling; Mills, Denise A.; Buhrow, Leann; Hiser, Carrie; Ferguson-Miller, Shelagh (Michigan)

    2010-09-02

    Micromolar concentrations of the bile salt deoxycholate are shown to rescue the activity of an inactive mutant, E101A, in the K proton pathway of Rhodobacter sphaeroides cytochrome c oxidase. A crystal structure of the wild-type enzyme reveals, as predicted, deoxycholate bound with its carboxyl group at the entrance of the K path. Since cholate is a known potent inhibitor of bovine oxidase and is seen in a similar position in the bovine structure, the crystallographically defined, conserved steroid binding site could reveal a regulatory site for steroids or structurally related molecules that act on the essential K proton path.

  19. The biological functions of polyamine oxidation products by amine oxidases: Perspectives of clinical applications

    Microsoft Academic Search

    E. Agostinelli; G. Arancia; L. Dalla Vedova; F. Belli; M. Marra; M. Salvi; A. Toninello

    2004-01-01

    Summary. The polyamines spermine, spermidine and putrescine are ubiquitous cell components. If they accumulate excessively within the cells, due either to very high extracellular concentrations or to deregulation of the systems which control polyamine homeostasis, they can induce toxic effects. These molecules are substrates of a class of enzymes that includes monoamine oxidases, diamine oxidases, polyamine oxidases and copper containing

  20. Xanthine Oxidase Inhibition Attenuates Endothelial Dysfunction Caused by Chronic Intermittent Hypoxia in Rats

    Microsoft Academic Search

    John M. Dopp; Nathan R. Philippi; Noah J. Marcus; E. Burt Olson; Cynthia E. Bird; John J. M. Moran; Scott W. Mueller; Barbara J. Morgan

    2011-01-01

    Background: Xanthine oxidase is a major source of superoxide in the vascular endothelium. Previous work in humans demonstrated improved conduit artery function following xanthine oxidase inhibition in patients with obstructive sleep apnea. Objectives: To determine whether impairments in endothelium-dependent vasodilation produced by exposure to chronic intermittent hypoxia are prevented by in vivo treatment with allopurinol, a xanthine oxidase inhibitor. Methods:

  1. Determination of a Large Reorganization Energy Barrier for Hydride Abstraction by Glucose Oxidase

    E-print Network

    Roth, Justine P.

    Determination of a Large Reorganization Energy Barrier for Hydride Abstraction by Glucose Oxidase the context of Marcus theory.3 Glucose oxidase (GO) uses a noncovalently bound flavin (FAD) to oxidize sugars accelerations in a number of C-H oxidizing enzymes including glucose oxidase.7 In previous studies, it was shown

  2. Adsorption of Glucose Oxidase onto Single-Walled Carbon Nanotubes and Its Application in

    E-print Network

    Resasco, Daniel

    Adsorption of Glucose Oxidase onto Single-Walled Carbon Nanotubes and Its Application in Layer suspension-dialysis method to adsorb the redox enzyme glucose oxidase (GOX) onto single-walled carbon nano. To test this we used the enzyme glucose oxidase (GOX), which is * To whom correspondence should

  3. Cloning and characterization of Arabidopsis and Brassica juncea flavin-containing amine oxidases

    Microsoft Academic Search

    Tze Soo Lim; Thiruvetipuram Rajam Chitra; Ping Han; Eng Chong Pua; Hao Yu

    2006-01-01

    Polyamines (PAs) are low molecular weight metabolites involved in various physiological and developmental processes in eukaryotic and prokaryotic cells. The cellular PA level is regulated in part by the action of amine oxidases (AOs) including copper diamine oxi- dases (DAOs) and flavoprotein polyamine oxidases (PAOs). In this study, the isolation and characterization of flavin amine oxidases (FAOs) from Brassica juncea

  4. Free and Membrane-Bound Xanthine Oxidase in Bovine Milk During Cooling and Heating

    Microsoft Academic Search

    M. K. Bhavadasan; N. C. Ganguli

    1980-01-01

    The effect of cold storage (5 C, 24 h) and heat treatment (60 C, 5 rain) of milk on activities of free and membrane-bound xanthine oxidase has been studied. Both treatments enhanced total xanthine oxi- dase activity in milk. Activity of mem- brane-bound xanthine oxidase increased and free xanthine oxidase decreased in buttermilk while it increased in skim milk on

  5. Kinetics of proton pumping in cytochrome c oxidase Anatoly Yu. Smirnov,1,2,3,a

    E-print Network

    Nori, Franco

    Kinetics of proton pumping in cytochrome c oxidase Anatoly Yu. Smirnov,1,2,3,a Lev G. Mourokh,4 propose a simple model of cytochrome c oxidase, including four redox centers and four protonable sites of the respiratory chain of animal cells and bacteria, cytochrome c oxidase CcO , operates as an efficient nanoscale

  6. Transferability of microsatellite and sequence tagged site markers in Oryza species.

    PubMed

    Brondani, Claudio; Rangel, Paulo Hideo Nakano; Borba, Tereza Cristina Oliveira; Brondani, Rosana Pereira Vianello

    2003-01-01

    The genus Oryza comprises 22 species which are potentially useful as a source of genetic variability that can be introgressed into the worldwide cultivated rice, Oryza sativa. Molecular markers are useful tools for monitoring gene introgressions and for detecting polymorphism among species. In this study, cross-amplification was estimated among 28 accessions of 16 Oryza species, representing the genomes AA, BB, CC, BBCC and CCDD, using 59 microsatellite (OG, OS and RM series) and 15 STS (Sequence Tagged Sites) markers. All markers amplified at least one Oryza species, indicating different levels of transferability across species. Markers based on microsatellite sequences amplified 37 % of the accessions, with an average of 6.58 alleles per locus and an average polymorphism information content (PIC) of 70 %. For STS markers, the amplification level was 53.3 %, and the average number of alleles and PIC values were 1.6 and 10 %, respectively. These Results showed that although the STS markers detected a reduced level of genetic diversity, the transferability was higher, indicating that they can be used for genetic analysis when evaluating less genetically related species of Oryza. Among the microsatellite markers, an analysis of species with an AA genome showed that the OG markers produced the highest level of polymorphic loci (54.6 %), followed by RM markers (48 %). Highly polymorphic and transferable molecular markers in Oryza can be useful for exploiting the genetic resources of this genus, for detecting allelic variants in loci associated with important agronomic traits, and for monitoring alleles introgressed from wild relatives to cultivated rice. PMID:14641482

  7. Forage polyphenol oxidase and ruminant livestock nutrition

    PubMed Central

    Lee, Michael R. F.

    2014-01-01

    Polyphenol oxidase (PPO) is predominately associated with the detrimental effect of browning fruit and vegetables, however, interest within PPO containing forage crops (crops to be fed to animals) has grown since the browning reaction was associated with reduced nitrogen (N) losses in silo and the rumen. The reduction in protein breakdown in silo of red clover (high PPO forage) increased the quality of protein, improving N-use efficiency [feed N into product N (e.g., Milk): NUE] when fed to ruminants. A further benefit of red clover silage feeding is a significant reduction in lipolysis (cleaving of glycerol-based lipid) in silo and an increase in the deposition of beneficial C18 polyunsaturated fatty acid (PUFA) in animal products, which has also been linked to PPO activity. PPOs protection of plant protein and glycerol based-PUFA in silo is related to the deactivation of plant proteases and lipases. This deactivation occurs through PPO catalyzing the conversion of diphenols to quinones which bind with cellular nucleophiles such as protein reforming a protein-bound phenol (PBP). If the protein is an enzyme (e.g., protease or lipase) the complexing denatures the enzyme. However, PPO is inactive in the anaerobic rumen and therefore any subsequent protection of plant protein and glycerol based-PUFA in the rumen must be as a result of events that occurred to the forage pre-ingestion. Reduced activity of plant proteases and lipases would have little effect on NUE and glycerol based-PUFA in the rumen due to the greater concentration of rumen microbial proteases and lipases. The mechanism for PPOs protection of plant protein in the rumen is a consequence of complexing plant protein, rather than protease deactivation per se. These complexed proteins reduce protein digestibility in the rumen and subsequently increase undegraded dietary protein flow to the small intestine. The mechanism for protecting glycerol-based PUFA has yet to be fully elucidated but may be associated with entrapment within PBP reducing access to microbial lipases or differences in rumen digestion kinetics of the forage and therefore not related to PPO activity. PMID:25538724

  8. Development and mapping of Oryza glumaepatula-derived microsatellite markers in the interspecific cross Oryza glumaepatula x O. sativa.

    PubMed

    Brondani, C; Brondani, R P; Rangel, P H; Ferreira, M E

    2001-01-01

    Wild germplasm of domesticated crops is a source of genetic variation little utilized in breeding programs. Interspecific crosses can potentially uncover novel gene combinations that can be important for quantitative trait analysis. The combined use of wide crosses and genetic maps of chromosomal regions associated with quantitative traits can be used to broaden the genetic basis of rice breeding programs. Oryza glumaepatula is a diploid (AA genome) wild rice species native from South and Central America. A genetic map was constructed with 162 PCR-based markers (155 microsatellite and 7 STS markers) using a backcross population derived from the cross O. glumaepatula, accession RS-16 from the Brazilian Amazon Region x O. sativa BG-90-2, an elite rice inbred line. The map included 47 new SSR markers developed from an O. glumaepatula genomic library enriched for AG/TC sequences. All SSR markers were able to amplify the O. sativa genome, indicating a high degree of SSR flanking region conservation between O. glumaepatula and O. sativa species. The map covered 1500.4 cM, with an average of one marker every 10 cM. Despite some chromosomes being more densely mapped, the overall coverage was similar to other maps developed for rice. The advantage to construct a SSR-based map is to permit the combination of the speed of the PCR reaction, and the codominant nature of the SSR marker, facilitating the QTL analysis and marker assisted selection for rice breeding programs. PMID:11525066

  9. Molecular abnormalities of coproporphyrinogen oxidase in patients with hereditary coproporphyria.

    PubMed

    Grandchamp, B; Lamoril, J; Puy, H

    1995-04-01

    Genetic defects of coproporphyrinogen oxidase (CPO) lead to hereditary coproporphyria, an inherited autosomal dominant porphyria. The recent cloning of human cDNAs and of the gene encoding CPO permits deducing the primary structure of the CPO protein and elucidating the molecular basis of HC in some families. PMID:7592568

  10. NADPH oxidases in Eukaryotes: red algae provide new hints!

    PubMed

    Hervé, Cécile; Tonon, Thierry; Collén, Jonas; Corre, Erwan; Boyen, Catherine

    2006-03-01

    The red macro-alga Chondrus crispus is known to produce superoxide radicals in response to cell-free extracts of its green algal pathogenic endophyte Acrochaete operculata. So far, no enzymes involved in this metabolism have been isolated from red algae. We report here the isolation of a gene encoding a homologue of the respiratory burst oxidase gp91(phox) in C. crispus, named Ccrboh. This single copy gene encodes a polypeptide of 825 amino acids. Search performed in available genome and EST algal databases identified sequences showing common features of NADPH oxidases in other algae such as the red unicellular Cyanidioschyzon merolae, the economically valuable red macro-alga Porphyra yezoensis and the two diatoms Phaeodactylum tricornutum and Thalassiosira pseudonana. Domain organization and phylogenetic relationships with plant, animal, fungal and algal NADPH oxidase homologues were analyzed. Transcription analysis of the C. crispus gene revealed that it was over-transcribed during infection of C. crispus gametophyte by the endophyte A. operculata, and after incubation in presence of atrazine, methyl jasmonate and hydroxyperoxides derived from C20 polyunsaturated fatty acids (PUFAs). These results also illustrate the interest of exploring the red algal lineage for gaining insight into the deep evolution of NADPH oxidases in Eukaryotes. PMID:16344959

  11. RESEARCH ARTICLE Open Access Multiple controls affect arsenite oxidase gene

    E-print Network

    Paris-Sud XI, Université de

    mutagenesis was performed. Transposon insertions resulting in a lack of arsenite oxidase activity disrupted to As(III). To get insight into the molecular mechanisms of this enzyme activity, a Tn5 transposon-component system. Remarkably, transposon insertions were also identified in rpoN coding for the alternative N sigma

  12. WHEAT FLOUR PROTEINS AS AFFECTED BY TRANSGLUTAMINASE AND GLUCOSE OXIDASE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Enzymes are good tools to modify wheat proteins by creating new bonds between the protein chains. In this study, the effect of the addition of glucose oxidase (GO) and transglutaminase (TG) on the wheat flour proteins is presented. The modification of wheat proteins was determined by analyzing the...

  13. Demographic, Biologic, and Other Variables Affecting Monoamine Oxidase Activity

    Microsoft Academic Search

    Donald S. Robinson; Alexander Nies

    1980-01-01

    Monoamine oxidase (MAO) activity has been shown to be influenced by a variety of demographic, biologic, and other variables. Human platelet, plasma, and brain enzyme activities correlate with age and are higher in women. Brain catecholamines tend to decrease with age. The acute effects of ethanol on platelet MAO do not appear to be significant, but chronic ethanol ingestion could

  14. Monoamine oxidase inhibition by Rhodiola rosea L. roots

    Microsoft Academic Search

    Daphne van Diermen; Andrew Marston; Juan Bravo; Marianne Reist; Pierre-Alain Carrupt; Kurt Hostettmann

    2009-01-01

    Aim of the studyRhodiola rosea L. (Crassulaceae) is traditionally used in Eastern Europe and Asia to stimulate the nervous system, enhance physical and mental performance, treat fatigue, psychological stress and depression. In order to investigate the influence of Rhodiola rosea L. roots on mood disorders, three extracts were tested against monoamine oxidases (MAOs A and B) in a microtitre plate

  15. Decolorization of phenolic effluents by soluble and immobilized phenol oxidases

    Microsoft Academic Search

    Susan Davis; Richard G. Burns

    1990-01-01

    Colour removal from phenplic industrial effluents by phenol oxidase enzymes and white-rot fungi was compared. Soluble laccase and horseradish peroxidase (HRP) removed colour from pulp mill (E), cotton mill hydroxide (OH) and cotton mill sulphide (S) effluents, but rapid and irreversible enzyme inactivation took place. Entrapment of laccase in alginate beads improved decolorization by factors of 3.5 (OH) and 2

  16. Studies on the mechanism of D-amino acid oxidase 

    E-print Network

    Kurtz, Kevin Anthony

    2000-01-01

    . The measured []V/K[] isotope effects decrease at higher pH and increase in D?O suggesting that the unprotonated form of the amino group is the substrate for D-amino acid oxidase. However, the results are inconclusive due to poor precision....

  17. HypC, the Anthrone Oxidase Involved in Aflatoxin Biosynthesis? †

    PubMed Central

    Ehrlich, Kenneth C.; Li, Ping; Scharfenstein, Leslie; Chang, Perng-Kuang

    2010-01-01

    On the basis of gene disruption and enzyme activity, hypC, an open reading frame in the region between the pksA (aflC) and nor-1 (aflD) genes in the aflatoxin biosynthesis gene cluster, encodes a 17-kDa oxidase that converts norsolorinic acid anthrone to norsolorinic acid. PMID:20348292

  18. Reducing peanut allergens by high pressure combined with polyphenol oxidase

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Polyphenol oxidase (PPO) has been shown to reduce major peanut allergens (Ara h 1 and Ara h 2). Because high pressure (HP) can increase enzyme activity, we postulated that further reduction of peanut allergens can be achieved through HP combined with PPO. Peanut extracts were treated with each of th...

  19. Molecular dynamics in cytochrome c oxidase Moessbauer spectra deconvolution

    SciTech Connect

    Bossis, Fabrizio [Department of Medical Biochemistry, Medical Biology and Medical Physics (DIBIFIM), University of Bari 'Aldo Moro', Bari (Italy)] [Department of Medical Biochemistry, Medical Biology and Medical Physics (DIBIFIM), University of Bari 'Aldo Moro', Bari (Italy); Palese, Luigi L., E-mail: palese@biochem.uniba.it [Department of Medical Biochemistry, Medical Biology and Medical Physics (DIBIFIM), University of Bari 'Aldo Moro', Bari (Italy)

    2011-01-07

    Research highlights: {yields} Cytochrome c oxidase molecular dynamics serve to predict Moessbauer lineshape widths. {yields} Half height widths are used in modeling of Lorentzian doublets. {yields} Such spectral deconvolutions are useful in detecting the enzyme intermediates. -- Abstract: In this work low temperature molecular dynamics simulations of cytochrome c oxidase are used to predict an experimentally observable, namely Moessbauer spectra width. Predicted lineshapes are used to model Lorentzian doublets, with which published cytochrome c oxidase Moessbauer spectra were simulated. Molecular dynamics imposed constraints to spectral lineshapes permit to obtain useful information, like the presence of multiple chemical species in the binuclear center of cytochrome c oxidase. Moreover, a benchmark of quality for molecular dynamic simulations can be obtained. Despite the overwhelming importance of dynamics in electron-proton transfer systems, limited work has been devoted to unravel how much realistic are molecular dynamics simulations results. In this work, molecular dynamics based predictions are found to be in good agreement with published experimental spectra, showing that we can confidently rely on actual simulations. Molecular dynamics based deconvolution of Moessbauer spectra will lead to a renewed interest for application of this approach in bioenergetics.

  20. Beyond brown: polyphenol oxidases as enzymes of plant specialized metabolism

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Most cloned and/or characterized plant polyphenol oxidases (PPOs) have catecholase 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 oth...

  1. PXO_00987, a putative acetyltransferase, is required for flagellin glycosylation, and regulates flagellar motility, exopolysaccharide production, and biofilm formation in Xanthomonas oryzae pv. oryzae.

    PubMed

    Li, Haiyun; Yu, Chao; Chen, Huamin; Tian, Fang; He, Chenyang

    2015-08-01

    Acetyltransferases catalyze an important process for sugar or protein modification. In the genome of Xanthomonas oryzae pv. oryzae (Xoo), the causal agent of bacterial blight of rice, there are 32 acetyltransferase-encoding genes belonging to different families. In this work, we focused on PXO_00987, which encodes a putative acetyltransferase in the flagellar regulon. We found that mutation of PXO_00987 gene abolished the glycosylation of wild-type flagellin protein of Xoo. In addition, the PXO_00987 mutant showed enhanced swimming motility, and decreased exopolysaccharide production and biofilm formation. Virulence assays demonstrated that the PXO_00987 mutant caused shorter disease length on rice leaves, suggesting that the function of PXO_00987 contributes to the pathogenesis of Xoo. PMID:26065383

  2. KdgR, an IClR Family Transcriptional Regulator, Inhibits Virulence Mainly by Repression of hrp Genes in Xanthomonas oryzae pv. oryzae?

    PubMed Central

    Lu, Yao; Rashidul, Islam M.; Hirata, Hisae; Tsuyumu, Shinji

    2011-01-01

    KdgR has been reported to negatively regulate the genes involved in degradation and metabolization of pectic acid and other extracellular enzymes in soft-rotting Erwinia spp. through direct binding to their promoters. The possible involvement of a KdgR orthologue in virulence by affecting the expression of extracellular enzymes in Xanthomonas oryzae pv. oryzae, the causal agent of rice blight disease, was examined by comparing virulence and regulation of extracellular enzymes between the wild type (WT) and a strain carrying a mutation in putative kdgR (?Xoo0310 mutant). This putative kdgR mutant of X. oryzae pv. oryzae showed increased pathogenicity on rice without affecting the regulation of extracellular enzymes, such as amylase, cellulase, xylanase, and protease. However, the mutant carrying a mutation in an ortholog of xpsL, which encodes the functional secretion machinery for the extracellular enzymes, showed a dramatic decrease in pathogenicity on rice. Both mutants of kdgR and of xpsL orthologs showed higher expression of two major hrp regulatory genes, hrpG and hrpX, and the genes in the hrp operons when grown in hrp-inducing medium. Thus, both genes were shown to be involved in repression of hrp genes. The kdgR ortholog was thought to suppress virulence mainly by repressing the expression of hrp genes without affecting the expression of extracellular enzymes, unlike findings for the kdgR gene in soft-rotting Erwinia spp. On the other hand, xpsL was confirmed to be involved in virulence by promoting the secretion of extracellular enzymes in spite of repressing the expression of the hrp genes. PMID:21984784

  3. Comparative proteomics reveals differential induction of both biotic and abiotic stress response associated proteins in rice during Xanthomonas oryzae pv. oryzae infection.

    PubMed

    Kumar, Anirudh; Bimolata, Waikhom; Kannan, Monica; Kirti, P B; Qureshi, Insaf Ahmed; Ghazi, Irfan Ahmad

    2015-07-01

    Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial blight disease in rice and brutally affects the yield up to 50 % of total production. Here, we report a comparative proteomics analysis of total foliar protein isolated from infected rice leaves of susceptible Pusa Basmati 1 (PB1) and resistant Oryza longistaminata genotypes. Two-dimensional gel electrophoresis (2-DE) coupled with matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) approaches identified 29 protein spots encoding unique proteins from both the genotypes. Identified proteins belonged to a large number of biological and molecular functions related to biotic and abiotic stress proteins which are potentially involved during Xoo infection. Biotic and abiotic stress-related proteins were induced during Xoo infection, indicating the activation of common stress pathway during bacterial blight infection. Candidate genes conferring tolerance against bacterial blight, which include germin-like protein, putative r40c1, cyclin-dependent kinase C, Ent-isokaur-15-ene synthase and glutathione-dependent dehydroascorbate reductase 1 (GSH-DHAR1), were also induced, with germin-like proteins induced only in the resistant rice genotype O. longistaminata. Energy, metabolism and hypothetical proteins were common among both the genotypes. Further, host defence/stress-related proteins were mostly expressed in resistant genotype O. longistaminata, indicating possible co-evolution of the pathogen and the wild rice, O. longistaminata. PMID:25648443

  4. Mapping the Catechol Binding Site in Dopamine D1 Receptors: Synthesis and Evaluation of Two Parallel Series of Bicyclic Dopamine Analogues

    PubMed Central

    Bonner, Lisa A.; Laban, Uros; Chemel, Benjamin R.; Juncosa, Jose I.; Lill, Markus A.; Watts, Val J.; Nichols, David E.

    2012-01-01

    A novel class of isochroman dopamine analogues, 1, originally reported by Abbott Laboratories, had greater than 100-fold selectivity for D1-like vs. D2-like receptors. We synthesized a parallel series of chroman compounds, 2, and showed that repositioning the oxygen in the heterocyclic ring reduced potency and conferred D2-like receptor selectivity to these compounds. In silico modeling supported the hypothesis that the altered pharmacology for 2 was due to potential intramolecular hydrogen bonding between the oxygen in the chroman ring and the meta-hydroxyl of the catechol moiety. This interaction realigns the catechol hydroxyl groups and disrupts key interactions between these ligands and critical serine residues in TM5 of the D1-like receptors. This hypothesis was tested by the synthesis and pharmacological evaluation of a parallel series of carbocyclic compounds, 3. Our results suggest that when the potential for intramolecular hydrogen bonding is removed, D1-like receptor potency and selectivity is restored. PMID:21538900

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

    SciTech Connect

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

    2012-04-23

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

  6. Replacement of a terminal cytochrome c oxidase by ubiquinol oxidase during the evolution of acetic acid bacteria.

    PubMed

    Matsutani, Minenosuke; Fukushima, Kota; Kayama, Chiho; Arimitsu, Misato; Hirakawa, Hideki; Toyama, Hirohide; Adachi, Osao; Yakushi, Toshiharu; Matsushita, Kazunobu

    2014-10-01

    The bacterial aerobic respiratory chain has a terminal oxidase of the heme-copper oxidase superfamily, comprised of cytochrome c oxidase (COX) and ubiquinol oxidase (UOX); UOX evolved from COX. Acetobacter pasteurianus, an ?-Proteobacterial acetic acid bacterium (AAB), produces UOX but not COX, although it has a partial COX gene cluster, ctaBD and ctaA, in addition to the UOX operon cyaBACD. We expressed ctaB and ctaA genes of A. pasteurianus in Escherichia coli and demonstrated their function as heme O and heme A synthases. We also found that the absence of ctaD function is likely due to accumulated mutations. These COX genes are closely related to other ?-Proteobacterial COX proteins. However, the UOX operons of AAB are closely related to those of the ?/?-Proteobacteria (?-type UOX), distinct from the ?/?-Proteobacterial proteins (?-type UOX), but different from the other ?-type UOX proteins by the absence of the cyoE heme O synthase. Thus, we suggest that A. pasteurianus has a functional ?-type UOX but has lost the COX genes, with the exception of ctaB and ctaA, which supply the heme O and A moieties for UOX. Our results suggest that, in AAB, COX was replaced by ?/?-Proteobacterial UOX via horizontal gene transfer, while the COX genes, except for the heme O/A synthase genes, were lost. PMID:24862920

  7. Inheritance of polyphenol oxidase activity in wheat breeding lines derived from matings of low polyphenol oxidase parents

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Polyphenol oxidase (PPO) in grain plays a major role in time-dependent discoloration of wheat (Triticum aestivum L.) products, especially fresh noodles. Breeding wheat cultivars with low or nil PPO activity can reduce the undesirable product darkening. The low PPO line PI 117635 was crossed to two...

  8. DEVELOPMENT OF 2,240 NEW SSR MARKERS FOR RICE (ORYZA SATIVA)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A total of 2,417 new di-, tri- and tetra-nucleotide SSR markers, representing 2,243 unique loci have been developed and experimentally validated for rice (Oryza sativa L.). Duplicate primer pairs are reported for 7% (174) of the loci. The majority (92%) of primer pairs were developed in regions flan...

  9. Genetic diversity and species relationships in the Oryza complex and glufosinate tolerance in rice 

    E-print Network

    Vaughan, Laura Kelly

    2005-08-29

    The weed red rice is a major problem in rice producing areas world wide. All of the red rice in commercial rice fields in the United States has traditionally been considered to be the same species as commercial rice, Oryza sativa. However, using DNA...

  10. Local differentiation amidst extensive allele sharing in Oryza nivara and O. rufipogon

    PubMed Central

    Banaticla-Hilario, Maria Celeste N; van den Berg, Ronald G; Hamilton, Nigel Ruaraidh Sackville; McNally, Kenneth L

    2013-01-01

    Genetic variation patterns within and between species may change along geographic gradients and at different spatial scales. This was revealed by microsatellite data at 29 loci obtained from 119 accessions of three Oryza series Sativae species in Asia Pacific: Oryza nivara Sharma and Shastry, O. rufipogon Griff., and O. meridionalis Ng. Genetic similarities between O. nivara and O. rufipogon across their distribution are evident in the clustering and ordination results and in the large proportion of shared alleles between these taxa. However, local-level species separation is recognized by Bayesian clustering and neighbor-joining analyses. At the regional scale, the two species seem more differentiated in South Asia than in Southeast Asia as revealed by FST analysis. The presence of strong gene flow barriers in smaller spatial units is also suggested in the analysis of molecular variance (AMOVA) results where 64% of the genetic variation is contained among populations (as compared to 26% within populations and 10% among species). Oryza nivara (HE = 0.67) exhibits slightly lower diversity and greater population differentiation than O. rufipogon (HE = 0.70). Bayesian inference identified four, and at a finer structural level eight, genetically distinct population groups that correspond to geographic populations within the three taxa. Oryza meridionalis and the Nepalese O. nivara seemed diverged from all the population groups of the series, whereas the Australasian O. rufipogon appeared distinct from the rest of the species. PMID:24101993

  11. Seedling vigour and the early growth of transplanted rice ( Oryza sativa )

    Microsoft Academic Search

    C. Ros; R. W. Bell; P. F. White

    2003-01-01

    Previous studies suggest that the positive response of transplanted rice (Oryza sativa L.) to nursery fertiliser application was due to increased seedling vigour or possibly to increased nutrient content. This paper presents results of two glasshouse experiments designed to test the hypothesis that seedling vigour was responsible for the response of transplanted seedlings to nursery treatments. The aim of the

  12. Common and distinct organ and stress responsive transcriptomic patterns in Oryza sativa and Arabidopsis thaliana

    Microsoft Academic Search

    Reena Narsai; Ian Castleden; James Whelan

    2010-01-01

    BACKGROUND: Arabidopsis thaliana is clearly established as the model plant species. Given the ever-growing demand for food, there is a need to translate the knowledge learned in Arabidopsis to agronomically important species, such as rice (Oryza sativa). To gain a comparative insight into the similarities and differences into how organs are built and how plants respond to stress, the transcriptomes

  13. Basil oil fumigation increases radiation sensitivity in adult Sitophilus oryzae (Coleoptera: Curculionidae).

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The biological activity of basil (Ocimum basilicum L.) oil was tested against the stored product pest rice weevil, Sitophilus oryzae(L.). Adult weevils were exposed to seven different concentrations of basil oil ranging from 0.12 µl/ml-0.60 µl/ml in Petri dishes and mortality was assessed at 3,4 and...

  14. Construction of six Oryza sativa x O. rufipogon Chromosome Segment Substitution Line (CSSL) Libraries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transgressive variation has been observed in rice (Oryza sativa) as an increase in grain yield and attributed to the ancestral parent, O. rufipogon, in mapping populations developed from several adapted rice varieties crossed with a single O. rufipogon accession. To explore this phenomenon of transg...

  15. Biological and mechanical control of Sitophilus oryzae (Coleoptera: Curculionidae) in rice

    Microsoft Academic Search

    Éric Lucas; Jordi Riudavets

    2002-01-01

    The combination of mechanical and biological methods was evaluated in the laboratory to assess their impact on the rice weevil Sitophilus oryzae in rice. Mechanical methods comprising the conventional polishing process applied either before or after infestation, resulting in reduced nutritional quality plus the added effect of mechanical impact in the presence of the pest, biological methods including parasitism by

  16. Journal of Stored Products Research 38 (2002) 293304 Biological and mechanical control of Sitophilus oryzae

    E-print Network

    Lucas, Éric

    2002-01-01

    of Sitophilus oryzae (Coleoptera: Curculionidae) in rice !Eric Lucas*, Jordi Riudavets Departament de Protecci because of the mechanical action of the process (Riudavets and Lucas, 2000; Lucas and Riudavets, 2000; Singh, 1981; Lucas and Riudavets, 2000; Ryoo and Cho, 1992; Haryadi and Fleurat- Lessard, 1994

  17. Genetic diversity associated with conservation of endangered Dongxiang wild rice ( Oryza rufipogon )

    Microsoft Academic Search

    J. Xie; H. A. Agrama; D. Kong; J. Zhuang; B. Hu; Y. Wan; W. Yan

    2010-01-01

    The wild progenitor species (Oryza rufipogon) of Asian cultivated rice (O. sativa L.) is located in Dongxiang county, China which is considered its the northernmost range worldwide. Nine ex situ and three in situ populations of the Dongxiang wild rice (DXWR) and four groups of modern cultivars were genotyped using 21 SSR markers for\\u000a study of population structure, conservation efficiency

  18. Development and evaluation of a core subset of the USDA rice (Oryza sativa L.) germplasm collection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A valuable core collection that is a subset of a whole germplasm collection should capture most of the variation present in the whole collection, while allowing for more efficient evaluation and management due to smaller size. The United States Department of Agriculture (USDA) rice (Oryza sativa L.)...

  19. Field resistance expressed when the PI-TA gene is compromised by Magnaporthe oryzae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Pi-ta gene provided 14 years of durable resistance to contemporary field population of Magnaporthe oryzae in southern USA rice production areas before being overcome during 2004 in ‘Banks’, a Pi-ta-based cultivar, by race IE-1k of the blast pathogen. Previously detected in production fields in 1...

  20. An expedited method to isolate DNA for PCR from Magnaporthe oryzae stored on filter paper

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fungus Magnaporthe oryzae is the causal agent for a wide range of cereal diseases. For long-term preservation, the fungus is grown and stored desiccated on filter papers at -20° C. Inoculated filter papers were cut into pieces from 0.5-1 cm diameter prior to storage. In the present study, a quic...

  1. Identification and characterization of a novel gene encoding the NBS1 protein in Pyricularia oryzae.

    PubMed

    Narukawa-Nara, Megumi; Sasaki, Kengo; Ishii, Akira; Baba, Kouhei; Amano, Kanako; Kuroki, Misa; Saitoh, Ken-Ichiro; Kamakura, Takashi

    2015-07-01

    The ascomycete Pyricularia oryzae (teleomorph: Magnaporthe oryzae) causes one of the most serious diseases known as rice blast. The Nijmegen breakage syndrome protein (NBS1) is essential for DNA repair; thus, we studied the P. oryzae NBS1 homolog (PoNBS1). A PoNBS1 null mutant exhibited high sensitivity to DNA damage-inducing agents. The mutant also exhibited the retarded hyphal growth, and induced abnormal conidial germination and shape, but showed normal appressorium formation. The phenotypes of the null mutant were complemented by introducing the cDNA of PoNBS1 driven by a TrpC promoter of Aspergillus nidulans. In addition, the null mutant similarly complemented with the PoNBS1 cDNA lacking the FHA domain that had a normal phenotype except for hyphal growth. These results suggest that PoNBS1 is involved in DNA repair and normal development in P. oryzae. Moreover, the FHA domain of PoNBS1 participates in normal hyphal growth. PMID:25774746

  2. Transcriptome Analysis of Early Responsive Genes in Rice during Magnaporthe oryzae Infection.

    PubMed

    Wang, Yiming; Kwon, Soon Jae; Wu, Jingni; Choi, Jaeyoung; Lee, Yong-Hwan; Agrawal, Ganesh Kumar; Tamogami, Shigeru; Rakwal, Randeep; Park, Sang-Ryeol; Kim, Beom-Gi; Jung, Ki-Hong; Kang, Kyu Young; Kim, Sang Gon; Kim, Sun Tae

    2014-12-01

    Rice blast disease caused by Magnaporthe oryzae is one of the most serious diseases of cultivated rice (Oryza sativa L.) in most rice-growing regions of the world. In order to investigate early response genes in rice, we utilized the transcriptome analysis approach using a 300 K tilling microarray to rice leaves infected with compatible and incompatible M. oryzae strains. Prior to the microarray experiment, total RNA was validated by measuring the differential expression of rice defense-related marker genes (chitinase 2, barwin, PBZ1, and PR-10) by RT-PCR, and phytoalexins (sakuranetin and momilactone A) with HPLC. Microarray analysis revealed that 231 genes were up-regulated (>2 fold change, p < 0.05) in the incompatible interaction compared to the compatible one. Highly expressed genes were functionally characterized into metabolic processes and oxidation-reduction categories. The oxidative stress response was induced in both early and later infection stages. Biotic stress overview from MapMan analysis revealed that the phytohormone ethylene as well as signaling molecules jasmonic acid and salicylic acid is important for defense gene regulation. WRKY and Myb transcription factors were also involved in signal transduction processes. Additionally, receptor-like kinases were more likely associated with the defense response, and their expression patterns were validated by RT-PCR. Our results suggest that candidate genes, including receptor-like protein kinases, may play a key role in disease resistance against M. oryzae attack. PMID:25506299

  3. Enhancement of the Stability of a Prolipase from Rhizopus oryzae toward Aldehydes by Saturation Mutagenesis

    Microsoft Academic Search

    Mirella Di Lorenzo; Aurelio Hidalgo; Rafael Molina; Juan A. Hermoso; Domenico Pirozzi; Uwe T. Bornscheuer

    2007-01-01

    A prolipase from Rhizopus oryzae (proROL) was engineered in order to increase its stability toward lipid oxidation products such as aldehydes with the aim of improving its performance in oleochemical industries. Out of 22 amino acid residues (15 Lys and 7 His) prone to react with aldehydes, 6 Lys and all His residues (except for the catalytic histidine) were chosen

  4. Alkylresorcylic acid synthesis by type III polyketide synthases from rice Oryza sativa

    Microsoft Academic Search

    Miku Matsuzawa; Yohei Katsuyama; Nobutaka Funa; Sueharu Horinouchi

    2010-01-01

    Alkylresorcinols, produced by various plants, bacteria, and fungi, are bioactive compounds possessing beneficial activities for human health, such as anti-cancer activity. In rice, they accumulate in seedlings, contributing to protection against fungi. Alkylresorcylic acids, which are carboxylated forms of alkylresorcinols, are unstable compounds and decarboxylate readily to yield alkylresorcinols. Genome mining of the rice Oryza sativa identified two type III

  5. A RAPID PCR-BASED METHOD TO DETECT MAGNAPORTHE ORYZAE FROM INFECTED PERENNIAL RYEGRASS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gray leaf spot of perennial ryegrass caused by Magnaporthe oryzae is a serious disease in the Midwestern U.S. Outbreaks normally occur from mid- to late summer and are especially severe on athletic fields and golf course fairways. Symptoms of gray leaf spot can be confused with those of other fungal...

  6. Genetic variation detected with RAPD markers among upland and lowland rice cultivars ( Oryza sativa L.)

    Microsoft Academic Search

    L.-X. Yu; H. T. Nguyen

    1994-01-01

    Genetic variation of nine upland and four lowland rice cultivars (Oryza sativa L.) was investigated at the DNA level using the randomly amplified polymorphic DNA (RAPD) method via the polymerase chain reaction (PCR). Forty-two random primers were used to amplify DNA segments and 260 PCR products were obtained. The results of agarosegel electrophoretic analysis of these PCR products indicated that

  7. Comparative Gene Expression Analysis of Fusarium graminearum in Triticum aestivum and Oryza sativa spp. japonica

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Negligible amounts of Type B trichothecenes accumulate in Oryza sativa spp. japonica infected with Fusarium graminearum relative to Triticum aestivum inoculated with an identical strain of the fungus. To identify differential fungal gene expression patterns that could be responsible for differences ...

  8. Comprehensive Analysis of NAC Family Genes in Oryza sativa and Arabidopsis thaliana

    Microsoft Academic Search

    Hisako Ooka; Kouji Satoh; Koji Doi; Toshifumi Nagata; Yasuhiro Otomo; Kazuo Murakami; Kenichi Matsubara; Naoki Osato; Jun Kawai; Piero Carninci; Yoshihide Hayashizaki; Koji Suzuki; Keiichi Kojima; Yoshinori Takahara; Koji Yamamoto; Shoshi Kikuchi

    2003-01-01

    The NAC domain was originally characterized from consensus sequences from petunia NAM and from Arabidopsis ATAF1, ATAF2, and CUC2. Genes containing the NAC domain (NAC family genes) are plant- specific transcriptional regulators and are expressed in various developmental stages and tissues. We per- formed a comprehensive analysis of NAC family genes in Oryza sativa (a monocot) and Arabidopsis thaliana (a

  9. Plantlet regeneration from somatic hybrids of rice ( Oryza sativa L.) and barnyard grass ( Echinochloa oryzicola Vasing)

    Microsoft Academic Search

    Rie Terada; Junko Kyozuka; Soryu Nishibayashi; Ko Shimamoto

    1987-01-01

    Somatic hybridization of rice (Oryza sativa L.) and barnyard grass (Echinochloa oryzicola), a close relative of barnyard millet, was attempted using electrofusion and a new culture method developed for rice protoplasts (Kyozuka et al. 1987) to incorporate some of the agronomically important characters of the latter species into rice. Selection of hybrids was based on inactivation of rice protoplasts by

  10. EXPRESSION PROFILING OF ORYZA SATIVA METAL HOMEOSTASIS GENES IN DIFFERENT RICE CULTIVARS USING CDNA MACROARRAYS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice (Oryza sativa) has shaped the cultures, diets and economies of billions of people; unfortunately, rice is a poor source of many essential micronutrients and vitamins. Deficiencies in these micronutrients are common in developing countries, especially where rice is the staple food. In order to i...

  11. Comparative analysis of the small RNA transcriptomes of Pinus contorta and Oryza sativa

    Microsoft Academic Search

    Ryan D. Morin; Gozde Aksay; Elena Dolgosheina; H. Alexander Ebhardt; Vincent Magrini; Elaine R. Mardis; S. Cenk Sahinalp; Peter J. Unrau

    2008-01-01

    The diversity of microRNAs and small-interfering RNAs has been extensively explored within angiosperms by focusing on a few key organisms such as Oryza sativa and Arabidopsis thaliana. A deeper division of the plants is defined by the radiation of the angiosperms and gymnosperms, with the latter comprising the commercially important conifers. The conifers are expected to provide important information regarding

  12. Irradiation quarantine treatment for control of Sitophilus oryzae (Coleoptera: Curculionidae) in rice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Irradiation is a quarantine treatment option for stored products pests. Dose response tests were conducted to identify a postharvest radiation treatment that would control rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae) in rice. Rice infested with adult or immature weevils was treate...

  13. Draft Genome Sequence of Streptacidiphilus oryzae TH49T, an Acidophilic Actinobacterium Isolated from Soil.

    PubMed

    Kim, Yu Ri; Park, Sewook; Kim, Tae-Su; Kim, Min-Kyeong; Han, Ji-Hye; Joung, Yochan; Kim, Seung Bum

    2015-01-01

    The draft genome sequence of Streptacidiphilus oryzae strain TH49(T), an acidophilic actinobacterium, was obtained. The draft is composed of six scaffolds totaling 7.8 Mbp, and it contains 6,829 protein-coding genes and 91 RNA genes. Genes related to respiratory nitrate reduction, siderophore production, and biosynthesis of other secondary metabolites were identified. PMID:26112795

  14. Draft Genome Sequence of Streptacidiphilus oryzae TH49T, an Acidophilic Actinobacterium Isolated from Soil

    PubMed Central

    Kim, Yu Ri; Park, Sewook; Kim, Tae-Su; Kim, Min-Kyeong; Han, Ji-Hye; Joung, Yochan

    2015-01-01

    The draft genome sequence of Streptacidiphilus oryzae strain TH49T, an acidophilic actinobacterium, was obtained. The draft is composed of six scaffolds totaling 7.8 Mbp, and it contains 6,829 protein-coding genes and 91 RNA genes. Genes related to respiratory nitrate reduction, siderophore production, and biosynthesis of other secondary metabolites were identified. PMID:26112795

  15. Induction of salicylic acid-mediated defense response in perennial ryegrass against infection by Magnaporthe oryzae.

    PubMed

    Rahman, Alamgir; Kuldau, Gretchen A; Uddin, Wakar

    2014-06-01

    Incorporation of plant defense activators is an innovative approach to development of an integrated strategy for the management of turfgrass diseases. The effects of salicylic acid (SA), benzothiadiazole (BTH, chemical analog of SA), jasmonic acid (JA), and ethephon (ET, an ethylene-releasing compound) on development of gray leaf spot in perennial ryegrass (Lolium perenne L.) caused by Magnaporthe oryzae were evaluated. Gray leaf spot disease incidence and severity were significantly decreased when plants were treated prior to inoculation with SA, BTH, and partially by ET but not by JA. Accumulation of endogenous SA and elevated expression of pathogenesis-related (PR)-1, PR-3.1, and PR-5 genes were associated with inoculation of plants by M. oryzae. Treatment of plants with SA enhanced expression levels of PR-3.1 and PR-5 but did not affect the PR-1 level, whereas BTH treatment enhanced relative expression levels of all three PR genes. Microscopic observations of leaves inoculated with M. oryzae revealed higher frequencies of callose deposition at the penetration sites in SA- and BTH-treated plants compared with the control plants (treated with water). These results suggest that early and higher induction of these genes by systemic resistance inducers may provide perennial ryegrass with a substantial advantage to defend against infection by M. oryzae. PMID:24328494

  16. Genome-wide association mapping reveals rich genetic architecture of complex traits in Oryza sativa

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Domesticated Asian rice, Oryza sativa, is a cultivated, inbreeding species that feeds over half of the world’s population. Understanding the genetic basis of diverse physiological, developmental, and morphological traits provides the basis for improving yield, quality and sustainability. Here, we pr...

  17. Genetic diversity of weedy red rice (Oryza sativa) in Arkansas, USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weedy red rice (Oryza sativa L.) is a problematic weed in rice. About 50% of US rice is produced in Arkansas and 60% of these fields have some red rice infestation. Red rice populations are morphologically and phenologically diverse. We hypothesize that red rice in Arkansas has high genetic diversit...

  18. Rhizopus delemar is the proper name for Rhizopus oryzae fumaric-malic acid producers

    Microsoft Academic Search

    Ayumi Abe; Yuji Oda; Kozo Asano; Teruo Sone

    2007-01-01

    The zygomycete Rhizopus oryzae currently is identified by sporangiophore morphology and growth temperature, but heterogeneity of the species has been reported. We examined the suitability of organic acid production as an effective taxonomic character for reclassification of the species. Strains were divided into two groups, LA (lactic acid pro- ducer) and FMA (fumaric-malic acid producers) according to organic acid production.

  19. Isoenzyme pattern and subcellular localisation of enzymes involved in fumaric acid accumulation by Rhizopus oryzae

    Microsoft Academic Search

    Yoav Peleg; Emil Battat; Michael C. Scrutton; Israel Goldberg

    1989-01-01

    Electrophoretic studies of fumarase and nicotine adenine dinucleotide (NAD)-malate dehydrogenase were carried out in the fumaric acid-accumulating fungus Rhizopus oryzae. The analyses revealed two fumarase isoenzymes, one localised solely in the cytosol and the other found both in the cytosol and in the mitochondrial fraction. The activity of the cytosolic isoenzyme of fumarase was higher during the acid production stage

  20. Inhibition of respiration of Aspergillus oryzae by adsorption of the mycelium on cellulose acetate fibres

    Microsoft Academic Search

    J. Meyrath; A. F. McIntosh

    1964-01-01

    Résumé L'intensité de respiration d'Aspergillus oryzae est fortement diminuée par adsorption du mycélium à un filtre d'acétate de cellulose soigneusement nettoyé. Cet effet suggère que certaines substances d'une importance capitale dans le métabolisme sont éliminées de la surface des hyphes.

  1. The stereochemical course of sulphuryl transfer catalysed by arylsulphatase II from Aspergillus oryzae.

    PubMed Central

    Chai, C L; Loughlin, W A; Lowe, G

    1992-01-01

    Phenyl [(R)-16O,17O,18O]sulphate was synthesized and used to study the stereochemical course of sulphuryl transfer to p-cresol catalysed by arylsulphatase II from Aspergillus oryzae. The reaction was shown to proceed with retention of configuration at the sulphur atom, providing evidence for the involvement of a sulpho-enzyme intermediate on the reaction pathway. PMID:1445242

  2. TECHNICAL REPORTS Water quality concerns have arisen related to rice (Oryza sativa

    E-print Network

    van Kessel, Chris

    TECHNICAL REPORTS 304 Water quality concerns have arisen related to rice (Oryza sativa L.) field applications. Water quality concerns have arisen in relation to the potential increase in DOC concentration drain water, which has the potential to contribute large amounts of dissolved organic carbon (DOC

  3. LACTIC ACID PRODUCTION BY SACCHAROMYCES CEREVISIAE EXPRESSING A RHIZOPUS ORYZAE LACTATE DEHYDROGENASE GENE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This work demonstrates the first example of a fungal LDH expressed in yeast. A L(+)-lactate dehydrogenase gene, ldhA, from the filamentous fungus Rhizopus oryzae was modified to be expressed under control of the Saccharomyces cerevisiae adhl promoter and terminator, then placed in a 2 micron contai...

  4. Use of Harvested Rice (Oryza Sativa) Fields for Diazinon Runoff Mitigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In landscapes defined by intensive agriculture, management practices are often needed to abate effects of potential non-point source pollution. Innovative research focuses on using rice (Oryza sativa), a wetland cereal crop, for pesticide mitigation both pre- and post-harvest. Because rice fields ...

  5. Effect of infection by Rhizopus oryzae on biochemical composition of stored potato tubers

    Microsoft Academic Search

    A. C. Amadioha

    1998-01-01

    The carbohydrate fractions, protein and lipid contents of two cultivars of potato namely, Irish Cobbler and Red Pontiac, were altered quantitatively by Rhizopus oryzae during the 10-day incubation period. Glucose content increased during the incubation period for both healthy and inoculated tubers. Starch, maltose, sucrose, protein and lipid contents decreased more rapidly in inoculated tubers than in healthy tubers in

  6. Transcriptome Analysis of Early Responsive Genes in Rice during Magnaporthe oryzae Infection

    PubMed Central

    Wang, Yiming; Kwon, Soon Jae; Wu, Jingni; Choi, Jaeyoung; Lee, Yong-Hwan; Agrawal, Ganesh Kumar; Tamogami, Shigeru; Rakwal, Randeep; Park, Sang-Ryeol; Kim, Beom-Gi; Jung, Ki-Hong; Kang, Kyu Young; Kim, Sang Gon; Kim, Sun Tae

    2014-01-01

    Rice blast disease caused by Magnaporthe oryzae is one of the most serious diseases of cultivated rice (Oryza sativa L.) in most rice-growing regions of the world. In order to investigate early response genes in rice, we utilized the transcriptome analysis approach using a 300 K tilling microarray to rice leaves infected with compatible and incompatible M. oryzae strains. Prior to the microarray experiment, total RNA was validated by measuring the differential expression of rice defense-related marker genes (chitinase 2, barwin, PBZ1, and PR-10) by RT-PCR, and phytoalexins (sakuranetin and momilactone A) with HPLC. Microarray analysis revealed that 231 genes were up-regulated (>2 fold change, p < 0.05) in the incompatible interaction compared to the compatible one. Highly expressed genes were functionally characterized into metabolic processes and oxidation-reduction categories. The oxidative stress response was induced in both early and later infection stages. Biotic stress overview from MapMan analysis revealed that the phytohormone ethylene as well as signaling molecules jasmonic acid and salicylic acid is important for defense gene regulation. WRKY and Myb transcription factors were also involved in signal transduction processes. Additionally, receptor-like kinases were more likely associated with the defense response, and their expression patterns were validated by RT-PCR. Our results suggest that candidate genes, including receptor-like protein kinases, may play a key role in disease resistance against M. oryzae attack. PMID:25506299

  7. The ultrasound-enhanced bioscouring performance of four polygalacturonase enzymes obtained from rhizopus oryzae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An analytical and statistical method has been developed to measure the ultrasound-enhanced bioscouring performance of milligram quantities of endo- and exo-polygalacturonase enzymes obtained from Rhizopus oryzae fungi. UV-Vis spectrophotometric data and a general linear mixed models procedure indic...

  8. ECONOMIC EFFECT OF DIFFERENT PLANT ESTABLISHMENT TECHNIQUES ON RICE, ORYZA SATIVA PRODUCTION

    Microsoft Academic Search

    Tahir Hussain Awan; Inalyat Ali; M. Ehsan Safdar; Mirza M. Ashraf; Muhammad Yaqub

    Economic effect of different plant establishment techniques on rice (Oryza sativa L.) production was studied at Rice Research Institute, Kala Shah Kaku, Lahore during kharif season 2001-2002 and 2002-2003. In this experiment, seven planting techniques were compared with the conventional method of transplanting. Five direct seeding techniques (drilling of soaked seed in wattar soil, drilling of soaked seed on raised

  9. What Does Genetic Diversity of Aspergillus flavus Tell Us About Aspergillus oryzae?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus and Aspergillus oryzae belong to Aspergillus section Flavi. They are closely related and are of significant economic importance. The former species has the ability to produce harmful aflatoxins while the latter is widely used in food fermentation and industrial enzyme production. ...

  10. Evidence for statistical epistasis between catechol- O -methyltransferase (COMT) and polymorphisms in RGS4, G72 (DAOA), GRM3, and DISC1: influence on risk of schizophrenia

    Microsoft Academic Search

    Kristin K. Nicodemus; Bhaskar S. Kolachana; Radhakrishna Vakkalanka; Richard E. Straub; Ina Giegling; Michael F. Egan; Dan Rujescu; Daniel R. Weinberger

    2007-01-01

    Catechol-O-methyltransferase (COMT) regulates dopamine degradation and is located in a genomic region that is deleted in a syndrome\\u000a associated with psychosis, making it a promising candidate gene for schizophrenia. COMT also has been shown to influence prefrontal\\u000a cortex processing efficiency. Prefrontal processing dysfunction is a common finding in schizophrenia, and a background of\\u000a inefficient processing may modulate the effect of

  11. Sensitization of nanocrystalline TiO2 anchored with pendant catechol functionality using a new tetracyanato ruthenium(II) polypyridyl complex.

    PubMed

    Kar, Prasenjit; Verma, Sandeep; Sen, Anik; Das, Amitava; Ganguly, Bishwajit; Ghosh, Hirendra Nath

    2010-05-01

    We have synthesized a new photoactive ruthenium(II) complex having a pendant catechol functionality (K(2)[Ru(CN)(4)(L)] (1) (L is 4-[2-(4'-methyl-2,2'-bipyridinyl-4-yl)vinyl]benzene-1,2-diol) for studying the dynamics of the interfacial electron transfer between nanoparticulate TiO(2) and the photoexcited states of this Ru(II) complex using femtosecond transient absorption spectroscopy. Steady-state absorption and emission studies revealed that the complex 1 showed a strong solvatochromic behavior in solvents or solvent mixtures of varying polarity. Our steady-state absorption studies further revealed that 1 is bound to TiO(2) surfaces through the catechol functionality, though 1 has two different types of functionalities (catecholate and cyanato) for binding to TiO(2) surfaces. The longer wavelength absorption band tail for 1, bound to TiO(2) through the proposed catecholate functionality, could also be explained on the basis of the DFT calculations. Dynamics of the interfacial electron transfer between 1 and TiO(2) nanoparticles was investigated by studying kinetics at various wavelengths in the visible and near-infrared region. Electron injection to the conduction band of the nanoparticulate TiO(2) was confirmed by detection of the conduction band electron in TiO(2) ([e(-)](TiO(2))(CB)) and cation radical of the adsorbed dye (1(*+)) in real time as monitored by transient absorption spectroscopy. A single exponential and pulse-width limited (<100 fs) electron injection was observed. Back electron transfer dynamics was determined by monitoring the decay kinetics of 1(*+) and [e(-)](TiO(2))(CB). This is the first report on ultrafast ET dynamics on TiO(2) nanoparticle surface using a solvatochromic sensitizer molecule. PMID:20349939

  12. Thin-layer chromatography of gallic acid, methyl gallate, pyrogallol, phloroglucinol, catechol, resorcinol, hydroquinone, catechin, epicatechin, cinnamic acid, p-coumaric acid, ferulic acid and tannic acid

    Microsoft Academic Search

    Om Prakash Sharma; Tej Krishan Bhat; Bhupinder Singh

    1998-01-01

    Six solvent systems of varying suitability are reported for the thin-layer chromatographic separation of simple phenolics and related compounds such as gallic acid, methyl gallate, pyrogallol, phloroglucinol, catechol, resorcinol, hydroquinone, catechin, epicatechin, cinnamic acid, p-coumaric acid, ferulic acid and tannic acid. The solvent system chloroform-ethyl acetate-acetic acid (50:50:1) facilitated the separation of all the compounds except pyrogallol and ferulic acid;

  13. Molecular aspects of catechol and pyrogallol inhibition of liver microsomal lipid peroxidation stimulated by ferrous ion-ADP-complexes or by carbon tetrachloride

    Microsoft Academic Search

    H. Kappus; H. Kieczka; M. Scheulen; H. Remmer

    1977-01-01

    Lipid peroxidation was induced in rat liver microsomes either by iron-ADP-complexes or by carbon tetrachloride in the presence of NADPH. Different compounds containing catechol or pyrogallol structures were examined for their activities to inhibit lipid peroxidation in both systems. In general, all compounds tested showed similar inhibitory activities on lipid peroxidation, if induced by ferrous ion-ADP-complexes or by carbon tetrachloride.

  14. Association of functional catechol O -methyl transferase ( COMT ) Val108Met polymorphism with smoking severity and age of smoking initiation in Chinese male smokers

    Microsoft Academic Search

    Song Guo; Da Fang Chen; Dong Feng Zhou; Hong Qiang Sun; Gui Ying Wu; Colin N. Haile; Therese A. Kosten; Thomas R. Kosten; Xiang Yang Zhang

    2007-01-01

    Rationale  Catechol-O-methyltransferase (COMT) is an enzyme involved in the degradation and inactivation of the neurotransmitter dopamine, which\\u000a is important in mediating drug reward such as nicotine in tobacco smoke. Different COMT alleles encode enzyme whose activity varies from three- to fourfold that may affect dopamine levels and alter subjective\\u000a effects of nicotine. Recent evidence also suggests that a COMT polymorphism may

  15. Evidence for a biopsychosocial influence on shoulder pain: Pain catastrophizing and catechol- O-methyltransferase (COMT) diplotype predict clinical pain ratings

    Microsoft Academic Search

    Steven Z. George; Margaret R. Wallace; Thomas W. Wright; Michael W. Moser; Warren H. Greenfield III; Brandon K. Sack; Deborah M. Herbstman; Roger B. Fillingim

    2008-01-01

    The experience of pain is believed to be influenced by social, cultural, environmental, psychological, and genetic factors. Despite this assertion, few studies have included clinically relevant pain phenotypes when investigating interactions among these variables. This study investigated whether psychological variables specific to fear-avoidance models and catechol-O-methyltransferase (COMT) genotype influenced pain ratings for a cohort of patients receiving operative treatment of

  16. Purification of enzymatically active human lysyl oxidase and lysyl oxidase-like protein from Escherichia coli inclusion bodies.

    PubMed

    Jung, Sang Taek; Kim, Moon Suk; Seo, Ji Yeon; Kim, Hyung Chul; Kim, Youngho

    2003-10-01

    Lysyl oxidase (LOX) is an extracellular copper dependent enzyme catalyzing lysine-derived cross-links in extracellular matrix proteins. Recent molecular cloning has revealed the existence of a LOX family consisting of LOX and four lysyl oxidase-like proteins (LOXLs; LOXL, LOXL2, LOXL3, and LOXL4). Each member of the LOX family contains a copper-binding domain, residues for lysyl-tyrosyl quinone, and a cytokine receptor-like domain. Very recently, novel functions, such as tumor suppression, cellular senescence, and chemotaxis, have been attributed to this family of amine oxidases, but functional differences among the family members have yet to be determined. For efficient expression and purification, we cloned the cDNAs corresponding to proteolytically processed forms of LOX (LOX-p) and LOXL (LOXL-p1 and LOXL-p2) into a bacterial expression vector pET21a with six continuous histidine codons attached to the 3' of the gene. The recombinant proteins were purified with nickel-chelating affinity chromatography and converted into enzymatically active forms by stepwise dialysis in the presence of N-lauroylsarcosinate and Cu2+. The purified LOX-p, LOXL-p1, and LOXL-p2 proteins showed specific amine oxidase activity of 0.097, 0.054, and 0.150 U/mg, respectively, which was inhibited by beta-aminopropionitrile (BAPN), a specific inhibitor of LOX. Availability of these pure and active forms of LOX and LOXLs will be significantly helpful in functional studies related to substrate specificity and crystal structures of this family of amine oxidases. PMID:14550642

  17. Simultaneous determination of 5-hydroxyindoles and catechols by high-performance liquid chromatography with fluorescence detection following derivatization with benzylamine and 1,2-diphenylethylenediamine.

    PubMed

    Fujino, Kaoru; Yoshitake, Takashi; Kehr, Jan; Nohta, Hitoshi; Yamaguchi, Masatoshi

    2003-09-19

    A highly selective and sensitive method for the simultaneous determination of 5-hydroxyindoles and catechols (serotonin, norepinephrine, dopamine and related compounds) by high-performance liquid chromatography with fluorescence detection is described. The method is based on the two-step precolumn derivatization of 5-hydroxyindoles and catechols with benzylamine (BA) and 1,2-diphenylethylenediamine (DPE), respectively, resulting in highly fluorescent and stable benzoxazole derivatives. The first derivatization with BA proceeds at room temperature (ca. 23 degrees C) for 2 min in a mixture of 0.3 M 3-cyclohexylamino-1-propanesulfonic acid buffer (pH 10.0) and methanol in the presence of potassium hexacyanoferrate(III). The subsequent second derivatization with DPE is carried out at 50 degrees C for 20 min in the presence of glycine. The resulting fluorescent derivatives of five 5-hydroxyindoles and seven catechols are separated on a reversed-phase column (150 x 1.5 mm I.D., packed with C18 silica, 5 microm) with isocratic elution using a mixture of acetonitrile-15 mM acetate buffer (pH 4.5) (34:66, v/v) containing 1 mM octanesulfonic acid sodium salt, and are detected spectrofluorimetrically at 480 nm with excitation at 345 nm. The detection limits (signal-to-noise ratio of 3) of the related compounds are 80 amol to 86 fmol for a 20-microl injection. PMID:14521313

  18. Liquid chromatography coupled to negative electrospray/ion trap mass spectrometry for the identification of isomeric glutathione conjugates of catechol estrogens

    NASA Astrophysics Data System (ADS)

    Rathahao, E.; Page, A.; Jouanin, I.; Paris, A.; Debrauwer, L.

    2004-02-01

    Conjugation to glutathione (GSH) represents an important detoxification pathway for preventing DNA damage due to oxidation products of catechol estrogens. In order to identify isomeric GSH conjugates of catechol estrogens, liquid chromatography coupled to electrospray/ion trap mass spectrometry was used. For this purpose, both positive and negative ion modes were applied, generating protonated and deprotonated species, respectively. Energy-resolved fragmentation of each isomeric quasi-molecular ion was achieved in two regions of the mass spectrometer: (i) the mass analyzer (ion trap mass spectrometer) and (ii) the interface region of the electrospray ionization source. The resonance excitation of [M+H]+ protonated ions carried out into the ion trap did not show any isomeric differentiation. Although ion source fragmentation of these same species allowed identification of each isomer, this method requires a good chromatographic separation, making it inefficient for the analysis of low sample amounts from in vitro or in vivo sources. Conversely, using resonance excitation of deprotonated ions, isomer distinction could be achieved. Thus, this technique should yield the best data for the direct characterization of isomers of catechol estrogen-GSH conjugates from biological samples.

  19. The effect of substituents on the surface modification of anatase nanoparticles with catecholate-type ligands: a combined DFT and experimental study.

    PubMed

    Savi?, Tatjana D; ?omor, Mirjana I; Nedeljkovi?, Jovan M; Veljkovi?, Dušan Ž; Zari?, Snežana D; Raki?, Vesna M; Jankovi?, Ivana A

    2014-10-14

    The surface modification of nanocrystalline TiO2 particles (45 Å) with catecholate-type ligands having different electron donating/electron withdrawing substituent groups, specifically 3-methylcatechol, 4-methylcatechol, 3-methoxycatechol, 3,4-dihydroxybenzaldehyde and 4-nitrocatechol, was found to alter the optical properties of nanoparticles in a similar way to catechol. The formation of the inner-sphere charge-transfer (CT) complexes results in a red shift of the semiconductor absorption compared to unmodified nanocrystallites and a reduction of the effective band gap, being slightly less pronounced in the case of electron withdrawing substituents. The investigated ligands have the optimal geometry for binding to surface Ti atoms, resulting in ring coordination complexes of the catecholate type (binuclear bidentate binding-bridging) thus restoring six-coordinated octahedral geometry of surface Ti atoms. From the absorption measurements (Benesi-Hildebrand plot), the stability constants in methanol/water = 90/10 solutions at pH 2 in the order of 10(3) M(-1) have been determined. The binding structures were investigated by using FTIR spectroscopy. Thermal stability of CT-complexes was investigated by using TG/DSC/MS analysis. Quantum chemical calculations on model systems using density functional theory (DFT) were performed to obtain the vibrational frequencies of charge transfer complexes, and the calculated values were compared with the experimental data. PMID:25166456

  20. A new amperometric biosensor based on Fe3O4/polyaniline/laccase/chitosan biocomposite-modified carbon paste electrode for determination of catechol in tea leaves.

    PubMed

    Sadeghi, Susan; Fooladi, Ebrahim; Malekaneh, Mohammad

    2015-02-01

    In the present study, a new biosensor based on laccase from Paraconiothyrium variabile was developed for catechol. The purified enzyme entrapped into the Fe3O4/polyaniline/chitosan (Fe3O4/polyaniline (PANI)/chitosan (CS)) biocomposite matrix film without the aid of other cross-linking reagents by a one-step electrodeposition on the surface of carbon paste electrode (CPE). The formed layer of biocomposite was characterized with scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). The biosensor was optimized with respect to biocomposite composition, enzyme loading, and solution pH by amperometry method. The biosensor exhibited noticeable eletrocatalytic ability toward catechol with a linear concentration range from 0.5 to 80 ?M and a detection limit of 0.4 ?M. The biosensor showed optimum response within 8 s, at pH 5, and 40 °C. The apparent Michaelis-Menten (K M (app)) was found to be 1.092 ?M. The fabricated biosensor could be applied for determination of catechol in tea leaf samples. PMID:25413793

  1. Formation of Light Absorbing Soluble Secondary Organics and Insoluble Polymeric Particles from the Dark Reaction of Catechol and Guaiacol with Fe(III).

    PubMed

    Slikboer, Samantha; Grandy, Lindsay; Blair, Sandra L; Nizkorodov, Sergey A; Smith, Richard W; Al-Abadleh, Hind A

    2015-07-01

    Transition metals such as iron are reactive components of environmentally relevant surfaces. Here, dark reaction of Fe(III) with catechol and guaiacol was investigated in an aqueous solution at pH 3 under experimental conditions that mimic reactions in the adsorbed phase of water. Using UV-vis spectroscopy, liquid chromatography, mass spectrometry, elemental analysis, dynamic light scattering, and electron microscopy techniques, we characterized the reactants, intermediates, and products as a function of reaction time. The reactions of Fe(III) with catechol and guaiacol produced significant changes in the optical spectra of the solutions due to the formation of light absorbing secondary organics and colloidal organic particles. The primary steps in the reaction mechanism were shown to include oxidation of catechol and guaiacol to hydroxy- and methoxy-quinones. The particles formed within a few minutes of reaction and grew to micron-size aggregates after half an hour reaction. The mass-normalized absorption coefficients of the particles were comparable to those of strongly absorbing brown carbon compounds produced by biomass burning. These results could account for new pathways that lead to atmospheric secondary organic aerosol formation and abiotic polymer formation on environmental surfaces mediated by transition metals. PMID:26039867

  2. Genomic Analysis of the Basal Lineage Fungus Rhizopus oryzae Reveals a Whole-Genome Duplication

    PubMed Central

    Ma, Li-Jun; Ibrahim, Ashraf S.; Skory, Christopher; Grabherr, Manfred G.; Burger, Gertraud; Butler, Margi; Elias, Marek; Idnurm, Alexander; Lang, B. Franz; Sone, Teruo; Abe, Ayumi; Calvo, Sarah E.; Corrochano, Luis M.; Engels, Reinhard; Fu, Jianmin; Hansberg, Wilhelm; Kim, Jung-Mi; Kodira, Chinnappa D.; Koehrsen, Michael J.; Liu, Bo; Miranda-Saavedra, Diego; O'Leary, Sinead; Ortiz-Castellanos, Lucila; Poulter, Russell; Rodriguez-Romero, Julio; Ruiz-Herrera, José; Shen, Yao-Qing; Zeng, Qiandong; Galagan, James; Birren, Bruce W.

    2009-01-01

    Rhizopus oryzae is the primary cause of mucormycosis, an emerging, life-threatening infection characterized by rapid angioinvasive growth with an overall mortality rate that exceeds 50%. As a representative of the paraphyletic basal group of the fungal kingdom called “zygomycetes,” R. oryzae is also used as a model to study fungal evolution. Here we report the genome sequence of R. oryzae strain 99–880, isolated from a fatal case of mucormycosis. The highly repetitive 45.3 Mb genome assembly contains abundant transposable elements (TEs), comprising approximately 20% of the genome. We predicted 13,895 protein-coding genes not overlapping TEs, many of which are paralogous gene pairs. The order and genomic arrangement of the duplicated gene pairs and their common phylogenetic origin provide evidence for an ancestral whole-genome duplication (WGD) event. The WGD resulted in the duplication of nearly all subunits of the protein complexes associated with respiratory electron transport chains, the V-ATPase, and the ubiquitin–proteasome systems. The WGD, together with recent gene duplications, resulted in the expansion of multiple gene families related to cell growth and signal transduction, as well as secreted aspartic protease and subtilase protein families, which are known fungal virulence factors. The duplication of the ergosterol biosynthetic pathway, especially the major azole target, lanosterol 14?-demethylase (ERG11), could contribute to the variable responses of R. oryzae to different azole drugs, including voriconazole and posaconazole. Expanded families of cell-wall synthesis enzymes, essential for fungal cell integrity but absent in mammalian hosts, reveal potential targets for novel and R. oryzae-specific diagnostic and therapeutic treatments. PMID:19578406

  3. Novel hydrophobic surface binding protein, HsbA, produced by Aspergillus oryzae.

    PubMed

    Ohtaki, Shinsaku; Maeda, Hiroshi; Takahashi, Toru; Yamagata, Youhei; Hasegawa, Fumihiko; Gomi, Katsuya; Nakajima, Tasuku; Abe, Keietsu

    2006-04-01

    Hydrophobic surface binding protein A (HsbA) is a secreted protein (14.5 kDa) isolated from the culture broth of Aspergillus oryzae RIB40 grown in a medium containing polybutylene succinate-co-adipate (PBSA) as a sole carbon source. We purified HsbA from the culture broth and determined its N-terminal amino acid sequence. We found a DNA sequence encoding a protein whose N terminus matched that of purified HsbA in the A. ozyzae genomic sequence. We cloned the hsbA genomic DNA and cDNA from A. oryzae and constructed a recombinant A. oryzae strain highly expressing hsbA. Orthologues of HsbA were present in animal pathogenic and entomopathogenic fungi. Heterologously synthesized HsbA was purified and biochemically characterized. Although the HsbA amino acid sequence suggests that HsbA may be hydrophilic, HsbA adsorbed to hydrophobic PBSA surfaces in the presence of NaCl or CaCl(2). When HsbA was adsorbed on the hydrophobic PBSA surfaces, it promoted PBSA degradation via the CutL1 polyesterase. CutL1 interacts directly with HsbA attached to the hydrophobic QCM electrode surface. These results suggest that when HsbA is adsorbed onto the PBSA surface, it recruits CutL1, and that when CutL1 is accumulated on the PBSA surface, it stimulates PBSA degradation. We previously reported that when the A. oryzae hydrophobin RolA is bound to PBSA surfaces, it too specifically recruits CutL1. Since HsbA is not a hydrophobin, A. oryzae may use several types of proteins to recruit lytic enzymes to the surface of hydrophobic solid materials and promote their degradation. PMID:16597938

  4. Novel Hydrophobic Surface Binding Protein, HsbA, Produced by Aspergillus oryzae

    PubMed Central

    Ohtaki, Shinsaku; Maeda, Hiroshi; Takahashi, Toru; Yamagata, Youhei; Hasegawa, Fumihiko; Gomi, Katsuya; Nakajima, Tasuku; Abe, Keietsu

    2006-01-01

    Hydrophobic surface binding protein A (HsbA) is a secreted protein (14.5 kDa) isolated from the culture broth of Aspergillus oryzae RIB40 grown in a medium containing polybutylene succinate-co-adipate (PBSA) as a sole carbon source. We purified HsbA from the culture broth and determined its N-terminal amino acid sequence. We found a DNA sequence encoding a protein whose N terminus matched that of purified HsbA in the A. ozyzae genomic sequence. We cloned the hsbA genomic DNA and cDNA from A. oryzae and constructed a recombinant A. oryzae strain highly expressing hsbA. Orthologues of HsbA were present in animal pathogenic and entomopathogenic fungi. Heterologously synthesized HsbA was purified and biochemically characterized. Although the HsbA amino acid sequence suggests that HsbA may be hydrophilic, HsbA adsorbed to hydrophobic PBSA surfaces in the presence of NaCl or CaCl2. When HsbA was adsorbed on the hydrophobic PBSA surfaces, it promoted PBSA degradation via the CutL1 polyesterase. CutL1 interacts directly with HsbA attached to the hydrophobic QCM electrode surface. These results suggest that when HsbA is adsorbed onto the PBSA surface, it recruits CutL1, and that when CutL1 is accumulated on the PBSA surface, it stimulates PBSA degradation. We previously reported that when the A. oryzae hydrophobin RolA is bound to PBSA surfaces, it too specifically recruits CutL1. Since HsbA is not a hydrophobin, A. oryzae may use several types of proteins to recruit lytic enzymes to the surface of hydrophobic solid materials and promote their degradation. PMID:16597938

  5. THE EQUILIBRIUM BETWEEN CYTOCHROME OXIDASE AND CARBON MONOXIDE

    PubMed Central

    Wald, George; Allen, David W.

    1957-01-01

    An evolution argument which attempted to trace the development of hemoglobins from such respiratory pigments as cytochrome oxidase presupposed that the latter possesses, in addition to its high affinity for oxygen, an approximately hyperbolic equilibrium function, and little if any Bohr effect (decline in affinity for oxygen with rise in acidity). Since cytochrome oxidase, unlike hemoglobin, is irreversibly oxidized by oxygen, the present experiments examine its combination with carbon monoxide, with which, like hemoglobin, it yields a true equilibrium. In all known hemoglobins the form of the equilibrium function and the vigor of the Bohr effect are similar with carbon monoxide and with oxygen, so that observations involving the former gas are relevant to the relations of the latter. The equilibrium function of cytochrome oxidase with carbon monoxide—percentage saturation vs. partial pressure of CO—is slightly inflected (in the Hill equation n = 1.26; for a hyperbola, n = 1). No Bohr effect is present in the range of pH 7–8. The pressure of carbon monoxide at which half-saturation occurs (p50) is about 0.17 mm. at 10–13°C. The affinity for carbon monoxide is therefore higher than commonly supposed. These properties are consistent with the evolution argument. They are important also for the physiological functioning of cytochrome oxidase, the nearly hyperbolic equilibrium function facilitating a high degree of saturation, and the lack of Bohr effect making this enzyme impervious to hyperacidity. The slight inflection of the equilibrium function shows that the Fe-porphyrin units of cytochrome oxidase interact to a degree, hence that the enzyme must contain more than one such unit per molecule. It is suggested that in cytochrome oxidase two Fe-porphyrin groups may unite with one oxygen in the manner Fe++-O2-Fe++; and that the evolution of hemoglobins proceeded over a first stage in which the hemes were separated so that each combines with only one molecule of oxygen, so tending to remain reduced; to a further stage in which the separated hemes interact through the protein to facilitate one another in combining with oxygen. PMID:13416533

  6. The virulence factor AvrXa7 of Xanthomonas oryzae pv. oryzae is a type III secretion pathway-dependent nuclear-localized double-stranded DNA-binding protein

    Microsoft Academic Search

    Bing Yang; Weiguang Zhu; Lowell B. Johnson; Frank F. White

    2000-01-01

    AvrXa7 is a member of the avrBs3 avirulence gene family, which encodes proteins targeted to plant cells by a type III secretion apparatus. AvrXa7, the product of avrXa7, is also a virulence factor in strain PXO86 of Xanthomonas oryzae pv. oryzae. Avirulence and virulence specificities are associated with the central repeat domain, which, in avrXa7, consists of 25.5 direct repeat

  7. Phosphatidic acid and diacylglycerol directly activate NADPH oxidase by interacting with enzyme components.

    PubMed

    Palicz, A; Foubert, T R; Jesaitis, A J; Marodi, L; McPhail, L C

    2001-02-01

    The enzyme NADPH oxidase is regulated by phospholipase D in intact neutrophils and is activated by phosphatidic acid (PA) plus diacylglycerol (DG) in cell-free systems. We showed previously that cell-free NADPH oxidase activation by these lipids involves both protein kinase-dependent and -independent pathways. Here we demonstrate that only the protein kinase-independent pathway is operative in a cell-free system of purified and recombinant NADPH oxidase components. Activation by PA + DG was ATP-independent and unaffected by the protein kinase inhibitor staurosporine, indicating the lack of protein kinase involvement. Both PA and DG were required for optimal activation to occur. The drug reduced activation of NADPH oxidase by either arachidonic acid or PA + DG, with IC(50) values of 46 and 25 microm, respectively. The optimal concentration of arachidonic acid or PA + DG for oxidase activation was shifted to the right with, indicating interference of the drug with the interaction of lipid activators and enzyme components. inhibited the lipid-induced aggregation/sedimentation of oxidase components p47(phox) and p67(phox), suggesting a disruption of the lipid-mediated assembly process. The direct effects of on NADPH oxidase activation complicate its use as a "specific" inhibitor of DG kinase. We conclude that the protein kinase-independent pathway of NADPH oxidase activation by PA and DG involves direct interaction with NADPH oxidase components. Thus, NADPH oxidase proteins are functional targets for these lipid messengers in the neutrophil. PMID:11060300

  8. Functional expression and peroxisomal targeting of rat urate oxidase in monkey kidney cells.

    PubMed

    Yeldandi, A V; Chu, R; Reddy, S K; Pan, J; Usuda, N; Lin, Y; Rao, M S; Reddy, J K

    1995-01-01

    Humans and hominoid primates lack the enzyme urate oxidase, which catalyzes the oxidation of uric acid to allantoin. In rats and most other mammals, urate oxidase is present as a crystalloid core within the peroxisomes of liver parenchymal cells. To determine whether functionally active recombinantly expressed urate oxidase can be targeted to the peroxisome as well as display the crystalloid core-like structure, we expressed rat urate oxidase cDNA in African green monkey kidney cells (CV-1 cells) under the control of a cytomegalovirus promoter. Cell lines stably expressing urate oxidase were isolated. Northern blot analysis revealed a 1.3-kb transcript and immunoblot analysis confirmed the presence of urate oxidase in the stably transfected cells. The recombinant urate oxidase expressed in CV-1 cells was functionally active. Immunofluorescence microscopy revealed that the expressed protein was visualized as discrete granules in the cytoplasm. Electron microscopy and immunocytochemical localization studies showed that the recombinantly expressed protein formed distinct crystalloid core structures with bundles of tubules within single membrane limited cytoplasmic organelles. On cross section, the recombinant urate oxidase tubular structures are arranged as circles of 10 surrounding a slightly larger circle. This arrangement is reminiscent of urate oxidase-containing cores in rat liver peroxisomes. Immunocytochemical studies confirmed that the recombinantly expressed urate oxidase is correctly targeted to the catalase-containing peroxisomes in these CV-1 cells. PMID:8821625

  9. The Escherichia coli CydX Protein Is a Member of the CydAB Cytochrome bd Oxidase Complex and Is Required for Cytochrome bd Oxidase Activity

    PubMed Central

    VanOrsdel, Caitlin E.; Bhatt, Shantanu; Allen, Rondine J.; Brenner, Evan P.; Hobson, Jessica J.; Jamil, Aqsa; Haynes, Brittany M.; Genson, Allyson M.

    2013-01-01

    Cytochrome bd oxidase operons from more than 50 species of bacteria contain a short gene encoding a small protein that ranges from ?30 to 50 amino acids and is predicted to localize to the cell membrane. Although cytochrome bd oxidases have been studied for more than 70 years, little is known about the role of this small protein, denoted CydX, in oxidase activity. Here we report that Escherichia coli mutants lacking CydX exhibit phenotypes associated with reduced oxidase activity. In addition, cell membrane extracts from ?cydX mutant strains have reduced oxidase activity in vitro. Consistent with data showing that CydX is required for cytochrome bd oxidase activity, copurification experiments indicate that CydX interacts with the CydAB cytochrome bd oxidase complex. Together, these data support the hypothesis that CydX is a subunit of the CydAB cytochrome bd oxidase complex that is required for complex activity. The results of mutation analysis of CydX suggest that few individual amino acids in the small protein are essential for function, at least in the context of protein overexpression. In addition, the results of analysis of the paralogous small transmembrane protein AppX show that the two proteins could have some overlapping functionality in the cell and that both have the potential to interact with the CydAB complex. PMID:23749980

  10. dffA Gene from Aspergillus oryzae encodes l-ornithine N 5-oxygenase and is indispensable for deferriferrichrysin biosynthesis

    Microsoft Academic Search

    Osamu Yamada; Suthamas Na Nan; Takeshi Akao; Mihoko Tominaga; Hisayuki Watanabe; Toshitsugu Satoh; Hitoshi Enei; Osamu Akita

    2003-01-01

    We identified and analyzed thedffA gene fromAspergillus oryzae which encodesl-ornithineN5-oxygenase involved in the biosynthesis of deferriferrichrysin, a type of siderophore which is a low-molecular-weight iron chelating compound. From among more than 20,000 clones in anA. oryzae EST (expressed sequence tag) library, we found only one clone encoding a protein that exhibited homology to theUstilago maydis sid1 protein (Sid1) andPseudomonas aeruginosa

  11. Morphological stability and metabolic activity of rice (Oryza sativa L.) protoplasts in media supplemented with polyamines and divalent cations 

    E-print Network

    Adhikary, Bharat Raj

    1979-01-01

    MORPHOLOGICAL STABILITY AND METABOLIC ACTIVITY OF RICE (ORYZA SATIVA L. ) PROTOPLASTS IN MEDIA SUPPLEMENTED WITH POLYAMINES AND DIVALENT CATIONS A Thesis by BHARAT RAJ ADHIKARY Submitted to the Graduate College of Texas A&M University... in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE August 1979 Major Subject: Genetics MORPHOLOGICAL STABILITY AND METABOLIC ACTIVITY QF RICE (ORYZA SATIVA L. ) PROTOPLASTS IN MEDIA SUPPLEMENTED WITH POLYAMINES AND DIVALENT...

  12. Identification of csypyrone B1 as the novel product of Aspergillus oryzae type III polyketide synthase CsyB

    Microsoft Academic Search

    Yasuyo Seshime; Praveen Rao Juvvadi; Katsuhiko Kitamoto; Yutaka Ebizuka; Isao Fujii

    2010-01-01

    As a novel superfamily of type III polyketide synthases (PKSs) in microbes, four genes, csyA, csyB, csyC, and csyD, were found in the genome of Aspergillus oryzae, an industrially important filamentous fungus. Although orthologs of csyA, csyC, and csyD genes are present in a closely related species, Aspergillus flavus, csyB gene is unique to A. oryzae. To identify its function,

  13. Aspergillus oryzae type III polyketide synthase CsyA is involved in the biosynthesis of 3,5-dihydroxybenzoic acid

    Microsoft Academic Search

    Yasuyo Seshime; Praveen Rao Juvvadi; Katsuhiko Kitamoto; Yutaka Ebizuka; Takamasa Nonaka; Isao Fujii

    2010-01-01

    As a novel superfamily of type III polyketide synthases in microbes, four genes csyA, csyB, csyC, and csyD, were found in the genome of Aspergillus oryzae, an industrially important filamentous fungus. In order to analyze their functions, we carried out the overexpression of csyA under the control of ?-amylase promoter in A. oryzae and identified 3,5-dihydroxybenzoic acid (DHBA) as the

  14. Alkaline Serine Proteinase: A Major Allergen of Aspergillus oryzae and Its Cross-Reactivity with Penicillium citrinum

    Microsoft Academic Search

    Horng-Der Shen; Win-Ling Lin; Ming F. Tam; Soo-Ray Wang; Jaw-Ji Tsai; Hong Chou; Shou-Hwa Han

    1998-01-01

    Background:Aspergillus species are common indoor airborne fungi and have been considered as causative agents of human allergic disorders. However, allergens of different Aspergillus species have not been effectively characterized. The object of this study was to identify and characterize IgE-binding components of Aspergillus oryzae. Methods. Allergens of A. oryzae were identified by immunoblot analysis using sera from asthmatic patients. The

  15. Naphthylisopropylamine and N-benzylamphetamine derivatives as monoamine oxidase inhibitors.

    PubMed

    Vilches-Herrera, Marcelo; Miranda-Sepúlveda, Juan; Rebolledo-Fuentes, Marco; Fierro, Angélica; Lühr, Susan; Iturriaga-Vasquez, Patricio; Cassels, Bruce K; Reyes-Parada, Miguel

    2009-03-15

    A series of naphthylisopropylamine and N-benzyl-4-methylthioamphetamine derivatives were evaluated as monoamine oxidase inhibitors. Their potencies were compared with those of a series of amphetamine derivatives, to test if the increase of electron richness of the aromatic ring and overall size of the molecule might improve their potency as enzyme inhibitors. Molecular dockings were performed to gain insight regarding the binding mode of these inhibitors and rationalize their different potencies. In the case of naphthylisopropylamine derivatives, the increased electron-donating capacity and size of the aromatic moiety resulting from replacement of the phenyl ring of amphetamine derivatives by a naphthalene system resulted in more potent compounds. In the other case, extension of the arylisopropylamine molecule by N-benzylation of the amino group led to a decrease in potency as monoamine oxidase inhibitors. PMID:19243954

  16. Cytochrome c oxidase: 25 years of the elusive proton pump.

    PubMed

    Wikström, Mårten

    2004-04-12

    Since its discovery [Nature 266 (1977) 271], the function of cytochrome c oxidase (and other haem-copper oxidases) as a redox-driven proton pump has been subject of both intense research and controversy, and is one of the key unsolved issues of bioenergetics and of biochemistry more generally. Despite the fact that the mechanism of proton translocation is not yet fully understood on the molecular level, many important details and principles have been learned. In the hope of accelerating progress, some of these will be reviewed here, together with a brief presentation of a novel proton pump mechanism, and of the emergence of a molecular basis for control of its efficiency. PMID:15100038

  17. Versatile roles of plant NADPH oxidases and emerging concepts.

    PubMed

    Kaur, Gurpreet; Sharma, Ashutosh; Guruprasad, Kunchur; Pati, Pratap Kumar

    2014-01-01

    NADPH oxidase (NOX) is a key player in the network of reactive oxygen species (ROS) producing enzymes. It catalyzes the production of superoxide (O2(-)), that in turn regulates a wide range of biological functions in a broad range of organisms. Plant Noxes are known as respiratory burst oxidase homologs (Rbohs) and are homologs of catalytic subunit of mammalian phagocyte gp91(phox). They are unique among other ROS producing mechanisms in plants as they integrate different signal transduction pathways in plants. In recent years, there has been addition of knowledge on various aspects related to its structure, regulatory components and associated mechanisms, and its plethora of biological functions. This update highlights some of the recent developments in the field with particular reference to important members of the plant kingdom. PMID:24561450

  18. Characterization of a monoclonal antibody to bovine xanthine oxidase.

    PubMed Central

    Kaetzel, C S; Mather, I H; Bruder, G; Madara, P J

    1984-01-01

    The isolation of a hybridoma cell line, C-41, secreting monoclonal antibody to bovine xanthine oxidase (EC 1.2.3.2), is described. The specificity of this antibody was determined by solid-phase immunoassay, immunoblotting procedures, affinity chromatography, immunoelectrophoresis and precipitation techniques. The results are compared with those obtained in similar specificity studies on a previously described monoclonal antibody secreted by hybridoma cell line A-94 [Mather, Nace, Johnson & Goldsby (1980) Biochem. J. 188, 925-928]. This latter antibody appears to bind to xanthine oxidase only when the enzyme is immobilized on a solid support such as a plastic plate or nitrocellulose paper. Potential problems in the determination of the specificity of monoclonal antibodies, especially towards membrane proteins of unknown biological activity, are discussed. Images Fig. 2. Fig. 3. Fig. 6. Fig. 7. PMID:6378181

  19. Catechol-O-Methyltransferase Val158Met Polymorphism on the Relationship between White Matter Hyperintensity and Cognition in Healthy People

    PubMed Central

    Liu, Mu-En; Huang, Chu-Chung; Yang, Albert C.; Tu, Pei-Chi; Yeh, Heng-Liang; Hong, Chen-Jee; Liou, Ying-Jay; Chen, Jin-Fan; Chou, Kun-Hsien; Lin, Ching-Po; Tsai, Shih-Jen

    2014-01-01

    Background White matter lesions can be easily observed on T2-weighted MR images, and are termed white matter hyperintensities (WMH). Their presence may be correlated with cognitive impairment; however, the relationship between regional WMH volume and catechol-O-methyltransferase (COMT) Val158Met polymorphism in healthy populations remains unclear. Methods We recruited 315 ethnic Chinese adults with a mean age of 54.9±21.8 years (range: 21–89 y) to examine the genetic effect of COMT on regional WMH and the manner in which they interact to affect cognitive function in a healthy adult population. Cognitive tests, structural MRI scans, and genotyping of COMT were conducted for each participant. Results Negative correlations between the Digit Span Forward (DSF) score and frontal WMH volumes (r?=??.123, P?=?.032, uncorrected) were noted. For the genetic effect of COMT, no significant difference in cognitive performance was observed among 3 genotypic groups. However, differences in WMH volumes over the subcortical region (P?=?.016, uncorrected), whole brain (P?=?.047, uncorrected), and a trend over the frontal region (P?=?.050, uncorrected) were observed among 3 COMT genotypic groups. Met homozygotes and Met/Val heterozygotes exhibited larger WMH volumes in these brain regions than the Val homozygotes. Furthermore, a correlation between the DSF and regional WMH volume was observed only in Met homozygotes. The effect size (cohen’s f) revealed a small effect. Conclusions The results indicate that COMT might modulate WMH volumes and the effects of WMH on cognition. PMID:24551149

  20. Structure-Based Evaluation of C5 Derivatives in the Catechol Diether Series Targeting HIV-1 Reverse Transcriptase

    PubMed Central

    Frey, Kathleen M.; Gray, William T.; Spasov, Krasimir A.; Bollini, Mariela; Gallardo-Macias, Ricardo; Jorgensen, William L.; Anderson, Karen S.

    2014-01-01

    Using a computationally driven approach, a class of inhibitors with picomolar potency known as the catechol diethers were developed targeting the non-nucleoside binding pocket (NNBP) of HIV-1 RT. Computational studies suggested that halogen bonding interactions between the C5 substituent of the inhibitor and backbone carbonyl of conserved residue Pro95 might be important. While the recently reported crystal structures of the RT complexes confirmed the interactions with the NNBP, they revealed the lack of a halogen bonding interaction with Pro95. In order to understand the effects of substituents at the C5 position, we determined additional crystal structures with 5-Br and 5-H derivatives. Using comparative structural analysis, we identified several conformations of the ethoxy uracil dependent on the strength of a van der Waals interaction with the C? of Pro95 and the C5 substitution. The 5-Cl and 5-F derivatives position the ethoxy uracil to make more hydrogen bonds, while the larger 5-Br and smaller 5-H position the ethoxy uracil to make fewer hydrogen bonds. EC50 values correlate with the trends observed in the crystal structures. The influence of C5 substitutions on the ethoxy uracil conformation may have strategic value, as future derivatives can possibly be modulated in order to gain additional hydrogen bonding interactions with resistant variants of RT. PMID:24289305

  1. Chemical intervention in bacterial lignin degradation pathways: Development of selective inhibitors for intradiol and extradiol catechol dioxygenases.

    PubMed

    Sainsbury, Paul D; Mineyeva, Yelena; Mycroft, Zoe; Bugg, Timothy D H

    2015-06-01

    Bacterial lignin degradation could be used to generate aromatic chemicals from the renewable resource lignin, provided that the breakdown pathways can be manipulated. In this study, selective inhibitors of enzymatic steps in bacterial degradation pathways were developed and tested for their effects upon lignin degradation. Screening of a collection of hydroxamic acid metallo-oxygenase inhibitors against two catechol dioxygenase enzymes, protocatechuate 3,4-dioxygenase (3,4-PCD) and 2,3-dihydroxyphenylpropionate 1,2-dioxygenase (MhpB), resulted in the identification of selective inhibitors D13 for 3,4-PCD (IC50 15?M) and D3 for MhpB (IC50 110?M). Application of D13 to Rhodococcus jostii RHA1 in minimal media containing ferulic acid led to the appearance of metabolic precursor protocatechuic acid at low concentration. Application of 1mM disulfiram, an inhibitor of mammalian aldehyde dehydrogenase, to R. jostii RHA1, gave rise to 4-carboxymuconolactone on the ?-ketoadipate pathway, whereas in Pseudomonas fluorescens Pf-5 disulfiram treatment gave rise to a metabolite found to be glycine betaine aldehyde. PMID:25984987

  2. Size-dependent and step-modulated supramolecular electrochemical properties of catechol-derived adlayers at Pt(hkl) surfaces.

    PubMed

    Rodríguez-López, Margarita; Herrero, Enrique; Climent, Víctor; Rodes, Antonio; Aldaz, Antonio; Feliu, Juan M; Carrasquillo, Arnaldo

    2013-10-22

    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 organic monolayers at metallic single-crystal electrode surfaces. A hard sphere model of surfaces and a simplified band formation model are used as a theoretical framework for interpretation of experimental results. The experimental results reveal (i) that supramolecular electrochemical effects may be confined, propagated, or modulated by the choice of atomic level crystallographic features (i.e.monatomic steps), deliberately introduced at metallic substrate surfaces, suggesting (ii) that substrate-defect engineering may be used to tune the macroscopic electronic properties of aromatic molecular adlayers and of smaller molecular aggregates. PMID:24116987

  3. Catechol-O-methyltransferase Val158Met polymorphism and hyperactivity symptoms in Egyptian children with autism spectrum disorder.

    PubMed

    Karam, Rehab A; Rezk, Noha A; Abdelrahman, Hadeel M; Hassan, Tamer H; Mohammad, Doaa; Hashim, Haitham M; Fattah, Nelly R A Abdel

    2013-07-01

    Catechol-O-methyltransferase (COMT) plays an important role in the catabolism of brain dopamine and norepinephrine, which have been implicated in the pathogenesis of Autism spectrum disorder (ASD) as well as in other neuropsychatric disorders. We aimed to investigate the association of COMT Val158Met gene polymorphism with ASD and to examine the influence of such genotypes on hyperactivity symptoms in ASD patients. Eighty ASD patients (mean age 9 ± 1.9 years) and 100 control children (mean age 8.9 ± 1.9 years) were examined. COMT Val58Met polymorphism was genotyped using Tetra-primer ARMS-PCR method. The clinical diagnosis of ASD and ADHD were confirmed according to the DSM-IV criteria for research. We found no significant difference in genotypes or alleles' frequencies of COMT Val158Met polymorphism between ASD patients and control group. There was a significant association between COMT (Val/Val) genotype and both increasing CARS (p=0.001) and hyperactivity scores (p=0.006). Regarding Conner's Score, the DSM-IV hyperactive impulsive were significantly higher in Val/Val genotype than both Met/Val and Met/Met genotypes (p=0.03). Our data suggested an association between COMT Val58Met polymorphism and hyperactivity symptoms in Egyptian children with ASD. PMID:23643763

  4. Isolation and characterization of a new spore-forming sulfate-reducing bacterium growing by complete oxidation of catechol.

    PubMed

    Kuever, J; Kulmer, J; Jannsen, S; Fischer, U; Blotevogel, K H

    1993-01-01

    A new mesophilic sulfate-reducing bacterium, strain Groll, was isolated from a benzoate enrichment culture inoculated with black mud from a freshwater ditch. The isolate was a spore-forming, rod-shaped, motile, gram-positive bacterium. This isolate was able of complete oxidation of several aromatic compounds including phenol, catechol, benzoate, p- and m-cresol, benzyl alcohol and vanillate. With hydrogen and carbon dioxide, formate or O-methylated aromatic compounds, autotrophic growth during sulfate reduction or homoacetogenesis was demonstrated. Lactate was not used as a substrate. SO4(2-), SO3(2-), and S2O3(2-) were utilized as electron acceptors. Although strain Groll originated from a freshwater habitat, salt concentrations of up to 30 g.l-1 were tolerated. The optimum temperature for growth was 35-37 degrees C. The G + C content of DNA was 42.1 mol%. This isolate is described as a new species of the genus Desulfotomaculum. PMID:8481092

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

    PubMed

    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

  6. Oxygen reactivity of mammalian sulfite oxidase provides a concept for the treatment of sulfite oxidase deficiency.

    PubMed

    Belaidi, Abdel A; Röper, Juliane; Arjune, Sita; Krizowski, Sabina; Trifunovic, Aleksandra; Schwarz, Guenter

    2015-07-15

    Mammalian sulfite oxidase (SO) is a dimeric enzyme consisting of a molybdenum cofactor- (Moco) and haem-containing domain and catalyses the oxidation of toxic sulfite to sulfate. Following sulfite oxidation, electrons are passed from Moco via the haem cofactor to cytochrome c, the terminal electron acceptor. In contrast, plant SO (PSO) lacks the haem domain and electrons shuttle from Moco to molecular oxygen. Given the high similarity between plant and mammalian SO Moco domains, factors that determine the reactivity of PSO towards oxygen, remained unknown. In the present study, we generated mammalian haem-deficient and truncated SO variants and demonstrated their oxygen reactivity by hydrogen peroxide formation and oxygen-consumption studies. We found that intramolecular electron transfer between Moco and haem showed an inverse correlation to SO oxygen reactivity. Haem-deficient SO variants exhibited oxygen-dependent sulfite oxidation similar to PSO, which was confirmed further using haem-deficient human SO in a cell-based assay. This finding suggests the possibility to use oxygen-reactive SO variants in sulfite detoxification, as the loss of SO activity is causing severe neurodegeneration. Therefore we evaluated the potential use of PEG attachment (PEGylation) as a modification method for future enzyme substitution therapies using oxygen-reactive SO variants, which might use blood-dissolved oxygen as the electron acceptor. PEGylation has been shown to increase the half-life of other therapeutic proteins. PEGylation resulted in the modification of up to eight surface-exposed lysine residues of SO, an increased conformational stability and similar kinetic properties compared with wild-type SO. PMID:26171830

  7. Evaluation of Oxalate Decarboxylase and Oxalate Oxidase for Industrial Applications

    Microsoft Academic Search

    Pierre Cassland; Anders Sjöde; Sandra Winestrand; Leif J. Jönsson; Nils-Olof Nilvebrant

    2010-01-01

    Increased recirculation of process water has given rise to problems with formation of calcium oxalate incrusts (scaling) in\\u000a the pulp and paper industry and in forest biorefineries. The potential in using oxalate decarboxylase from Aspergillus niger for oxalic acid removal in industrial bleaching plant filtrates containing oxalic acid was examined and compared with barley\\u000a oxalate oxidase. Ten different filtrates from

  8. Comparative substrate-inhibitor analysis of mink liver monoamine oxidases

    Microsoft Academic Search

    O. V. Yagodina

    2010-01-01

    Comparative substrate-inhibitor analysis of catalytic properties of liver monoamine oxidases (MAO) was performed in the mature\\u000a males of the American mink Mustela vison and the European mink Mustela lutreola. The action on the MAO activity was studied of alkaloids of the benzo[c]phenanthridine group: sanguinarine and chelidonine,\\u000a diisoquinoline alkaloid berberine, medicinal agents “Ukrain” and “Sanguirythrin” as well as derivatives of 2-propylamine:

  9. NADPH oxidases in Eukaryotes: red algae provide new hints!

    Microsoft Academic Search

    Cécile Hervé; Thierry Tonon; Jonas Collén; Erwan Corre; Catherine Boyen

    2006-01-01

    The red macro-alga Chondrus crispus is known to produce superoxide radicals in response to cell-free extracts of its green algal pathogenic endophyte Acrochaete operculata. So far, no enzymes involved in this metabolism have been isolated from red algae. We report here the isolation of a gene\\u000a encoding a homologue of the respiratory burst oxidase gp91phox in C. crispus, named Ccrboh.

  10. Physiological and pathological implications of semicarbazide-sensitive amine oxidase

    Microsoft Academic Search

    Peter H Yu; Shannon Wright; Ellen H Fan; Zhao-Rong Lun; Diana Gubisne-Harberle

    2003-01-01

    Semicarbazide-sensitive amine oxidase (SSAO) catalyzes the deamination of primary amines. Such deamination has been shown capable of regulating glucose transport in adipose cells. It has been independently discovered that the primary structure of vascular adhesion protein-1 (VAP-1) is identical to SSAO. VAP-1 regulates leukocyte migration and is related to inflammation. Increased serum SSAO activities have been found in patients with

  11. Characteristics and biotechnological applications of microbial cholesterol oxidases

    Microsoft Academic Search

    Noriyuki Doukyu

    2009-01-01

    Microbial cholesterol oxidase is an enzyme of great commercial value, widely employed by laboratories routinely devoted to\\u000a the determination of cholesterol concentrations in serum, other clinical samples, and food. In addition, the enzyme has potential\\u000a applications as a biocatalyst which can be used as an insecticide and for the bioconversion of a number of sterols and non-steroidal\\u000a alcohols. The enzyme

  12. Lysyl Oxidase ( Lox ) Gene Deficiency Affects Osteoblastic Phenotype

    Microsoft Academic Search

    N. Pischon; J. M. Mäki; P. Weisshaupt; N. Heng; A. H. Palamakumbura; P. N’Guessan; A. Ding; R. Radlanski; H. Renz; T. A. L. J. J. Bronckers; J. Myllyharju; A. M. Kielbassa; B. M. Kleber; J.-P. Bernimoulin; P. C. Trackman

    2009-01-01

    Lysyl oxidase (LOX) catalyzes cross-linking of elastin and collagen, which is essential for the structural integrity and function\\u000a of bone tissue. The present study examined the role of Lox gene deficiency for the osteoblast phenotype in primary calvarial osteoblasts from E18.5 Lox knockout (Lox\\u000a \\u000a ?\\/?\\u000a ) and wild type (wt) (C57BL\\/6) mice. Next to Lox gene depletion, mRNA expression of

  13. Subpollen particles: Carriers of allergenic proteins and oxidases

    PubMed Central

    Bacsi, Attila; Choudhury, Barun K.; Dharajiya, Nilesh; Sur, Sanjiv; Boldogh, Istvan

    2011-01-01

    Background Pollen is known to induce allergic asthma in atopic individuals, although only a few inhaled pollen grains penetrate into the lower respiratory tract. Objective We sought to provide evidence that subpollen particles (SPPs) of respirable size, possessing both antigenic and redox properties, are released from weed pollen grains and to test their role in allergic airway inflammation. Methods The release of SPPs was analyzed by means of microscopic imaging and flow cytometry. The redox properties of SPPs and the SPP-mediated oxidative effect on epithelial cells were determined by using redox-sensitive probes and specific inhibitors. Western blotting and amino acid sequence analysis were used to examine the protein components of the SPP. The allergenic properties of the SPP were determined in a murine model of experimental asthma. Results Ragweed pollen grains released 0.5 to 4.5 ?m of SPPs on hydration. These contained Amb a 1, along with other allergenic proteins of ragweed pollen, and possessed nicotinamide adenine dinucleotide (reduced) or nicotinamide adenine dinucleotide phosphate (reduced) [NAD(P)H] oxidase activity. The SPPs significantly increased the levels of reactive oxygen species (ROS) in cultured cells and induced allergic airway inflammation in the experimental animals. Pretreatment of the SPPs with NAD(P)H oxidase inhibitors attenuated their capacity to increase ROS levels in the airway epithelial cells and subsequent airway inflammation. Conclusions The allergenic potency of SPPs released from ragweed pollen grains is mediated in tandem by ROS generated by intrinsic NAD(P)H oxidases and antigenic proteins. Clinical implications Severe clinical symptoms associated with seasonal asthma might be explained by immune responses to inhaled SPPs carrying allergenic proteins and ROS-producing NAD(P)H oxidases. PMID:17030236

  14. Plant secondary metabolites- potent inhibitors of monoamine oxidase isoforms.

    PubMed

    Mathew, Bijo; Suresh, Jerad; Mathew, Githa E; Parasuraman, Ramamoorthy; Abdulla, Nalakathu

    2014-01-01

    Target of monoamine oxidase inhibitions are considered as the treatment of depressive states and neurodegenerative disorders, including Parkinson’s and Alzheimer’s diseases. Many medicinal chemistry research groups are actively working in this area for the development of most promising selective MAO inhibitors. Many plant isolates also showed remarkable MAO inhibition in recent years. The objective of this review is to identify the major MAO inhibitors secondary metabolites from plants like flavonoids, alkaloids and xanthones class of compounds. PMID:25142815

  15. Transcriptome and Proteome Expression Analysis of the Metabolism of Amino Acids by the Fungus Aspergillus oryzae in Fermented Soy Sauce

    PubMed Central

    Zhao, Guozhong; Yao, Yunping; Wang, Chunling; Tian, Fengwei; Liu, Xiaoming; Hou, Lihua; Yang, Zhen; Zhao, Jianxin; Zhang, Hao

    2015-01-01

    Amino acids comprise the majority of the flavor compounds in soy sauce. A portion of these amino acids are formed from the biosynthesis and metabolism of the fungus Aspergillus oryzae; however, the metabolic pathways leading to the formation of these amino acids in A. oryzae remain largely unknown. We sequenced the transcriptomes of A. oryzae 100-8 and A. oryzae 3.042 under similar soy sauce fermentation conditions. 2D gel electrophoresis was also used to find some differences in protein expression. We found that many amino acid hydrolases (endopeptidases, aminopeptidases, and X-pro-dipeptidyl aminopeptidase) were expressed at much higher levels (mostly greater than double) in A. oryzae 100-8 than in A. oryzae 3.042. Our results indicated that glutamate dehydrogenase may activate the metabolism of amino acids. We also found that the expression levels of some genes changed simultaneously in the metabolic pathways of tyrosine and leucine and that these conserved genes may modulate the function of the metabolic pathway. Such variation in the metabolic pathways of amino acids is important as it can significantly alter the flavor of fermented soy sauce. PMID:25945335

  16. 3,4-Dihydroxy-5-nitrobenzaldehyde (DHNB) is a Potent Inhibitor of Xanthine Oxidase: a potential therapeutic agent for treatment of hyperuricemia and gout

    PubMed Central

    Lü, Jian-Ming; Yao, Qizhi; Chen, Changyi

    2013-01-01

    Hyperuricemia, excess of uric acid in the blood, is a clinical problem that causes gout and is also considered a risk factor for cardiovascular disease. The enzyme xanthine oxidase (XO) produces uric acid during the purine metabolism; therefore, discovering novel XO inhibitors is an important strategy to develop an effective therapy for hyperuricemia and gout. We found that 3,4-dihydroxy-5-nitrobenzaldehyde (DHNB), a derivative of the natural substance protocatechuic aldehyde, potently inhibited XO activity with an IC50 value of 3 ?M. DHNB inhibited XO activity in a time-dependent manner, which was similar to that of allopurinol, a clinical XO inhibitory drug. DHNB displayed potent mixed-type inhibition of the activity of XO, and showed an additive effect with allopurinol at the low concentration. Structure-activity relationship studies of DHNB indicated that the aldehyde moiety, the catechol moiety, and nitration at C-5 were required for XO inhibition. DHNB interacted with the molybdenum center of XO and was slowly converted to its carboxylic acid at a rate of 10-10 mol/L/s. In addition, DHNB directly scavenged free radical DPPH and ROS, including ONOO? and HOCl. DHNB effectively reduced serum uric acid levels in allantoxanamide-induced hyperuricemic mice. Furthermore, mice given a large dose (500 mg/kg) of DHNB did not show any side effects, while 42% of allopurinol-treated mice died and their offspring lost their fur. Thus, DHNB could be an outstanding candidate for a novel XO inhibitory drug that has potent activity and low toxicity, as well as antioxidant activity and a distinct chemical structure from allopurinol. PMID:23994369

  17. Inhibition of plant and mammalian diamine oxidases by hydrazine and guanidine compounds.

    PubMed

    Biega?ski, T; Osi?ska, Z; Ma?li?ski, C

    1982-01-01

    1. Pig kidney and pea seedling diamine oxidases have similar sensitivity to methylhydrazine and phenylhydrazine as inhibitors. 2. Inhibition of pig kidney and pea seedling enzymes by hydrazine and guanidine compounds is time dependent. To reveal full inhibitory potency, methylhydrazine and aminoguanidine need longer preincubation with plant diamine oxidase as compared with mammalian diamine oxidase. 3. Impromidine, a known H2 histamine receptor agonist with guanidine and imidazole structures, and aminoguanidine have higher inhibitory activity towards pig kidney enzyme in comparison with the pea seedling one. 4. Impromidine inhibits pig kidney diamine oxidase in a noncompetitive manner. The Ki value is 6.6 muM. 5. The 24 hr dialysis of rat intestinal diamine oxidase preincubated with phenylhydrazine or impromidine only partially recovered the enzymic activities. 6. Impromidine inhibits mouse intestinal diamine oxidase in vivo. PMID:6215274

  18. The rice bacterial pathogen Xanthomonas oryzae pv. oryzae produces 3-hydroxybenzoic acid and 4-hydroxybenzoic acid via XanB2 for use in xanthomonadin, ubiquinone, and exopolysaccharide biosynthesis.

    PubMed

    Zhou, Lian; Huang, Tin-Wei; Wang, Jia-Yuan; Sun, Shuang; Chen, Gongyou; Poplawsky, Alan; He, Ya-Wen

    2013-10-01

    Xanthomonas oryzae pv. oryzae, the causal agent of rice bacterial blight, produces membrane-bound yellow pigments, referred to as xanthomonadins. Xanthomonadins protect the pathogen from photodamage and host-induced perioxidation damage. They are also required for epiphytic survival and successful host plant infection. Here, we show that XanB2 encoded by PXO_3739 plays a key role in xanthomonadin and coenzyme Q8 biosynthesis in X. oryzae pv. oryzae PXO99A. A xanB2 deletion mutant exhibits a pleiotropic phenotype, including xanthomonadin deficiency, producing less exopolysaccharide (EPS), lower viability and H2O2 resistance, and lower virulence. We further demonstrate that X. oryzae pv. oryzae produces 3-hydroxybenzoic acid (3-HBA) and 4-hydroxybenzoic acid (4-HBA) via XanB2. 3-HBA is associated with xanthomonadin biosynthesis while 4-HBA is mainly used as a precursor for coenzyme Q (CoQ)8 biosynthesis. XanB2 is the alternative source of 4-HBA for CoQ8 biosynthesis in PXO99A. These findings suggest that the roles of XanB2 in PXO99A are generally consistent with those in X. campestris pv. campestris. The present study also demonstrated that X. oryzae pv. oryzae PXO99A has evolved several specific features in 3-HBA and 4-HBA signaling. First, our results showed that PXO99A produces less 3-HBA and 4-HBA than X. campestris pv. campestris and this is partially due to a degenerated 4-HBA efflux pump. Second, PXO99A has evolved unique xanthomonadin induction patterns via 3-HBA and 4-HBA. Third, our results showed that 3-HBA or 4-HBA positively regulates the expression of gum cluster to promote EPS production in PXO99A. Taken together, the results of this study indicate that XanB2 is a key metabolic enzyme linking xanthomonadin, CoQ, and EPS biosynthesis, which are collectively essential for X. oryzae pv. oryzae pathogenesis. PMID:23718125

  19. Early diagnosis of blast fungus, Magnaporthe oryzae, in rice plant by using an ultra-sensitive electrically magnetic-controllable electrochemical biosensor.

    PubMed

    Yang, Weijuan; Zhang, Hongyan; Li, Mengxue; Wang, Zonghua; Zhou, Jie; Wang, Shihua; Lu, Guodong; Fu, FengFu

    2014-11-19

    As one of the most destructive and widespread disease of rice, Magnaporthe oryzae (also called Magnaporthe grisea) has a significant negative impact on rice production. Therefore, it is still in high demand to develop extremely sensitive and accurate methods for the early diagnosis of Magnaporthe oryzae (M. oryzae). In this study, we developed a novel magnetic-controllable electrochemical biosensor for the ultra sensitive and specific detection of M. oryzae in rice plant by using M. oryzae's chitinases (Mgchi) as biochemical marker and a rice (Oryza sativa) cDNA encoding mannose-binding jacalin-related lectin (Osmbl) as recognition probe. The proposed biosensor combined with the merits of chronoamperometry, electrically magnetic-controllable gold electrode and magnetic beads (MBs)-based palladium nano-particles (PdNPs) catalysis amplification, has an ultra-high sensitivity and specificity for the detection of trace M. oryzae in rice plant. It could be used to detect M. oryzae in rice plant in the initial infection stage (before any symptomatic lesions were observed) to help farmers timely manage the disease. In comparison with previous methods, the proposed method has notable advantages such as higher sensitivity, excellent specificity, short analysis time, robust resistibility to complex matrix and low cost etc. The success in this study provides a reliable approach for the early diagnosis and fast screening of M. oryzae in rice plant. PMID:25441164

  20. Protective action of NADPH oxidase inhibitors and role of NADPH oxidase in pathogenesis of colon inflammation in mice

    PubMed Central

    Ramonaite, Rima; Skieceviciene, Jurgita; Juzenas, Simonas; Salteniene, Violeta; Kupcinskas, Juozas; Matusevicius, Paulius; Borutaite, Vilmante; Kupcinskas, Limas

    2014-01-01

    AIM: To investigate the role of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase in colon epithelial cells in the pathogenesis of acute and chronic colon inflammation in a mouse model of dextran sulphate sodium (DSS)-induced colitis. METHODS: Balb/c mice were divided into three groups: 8 mice with acute DSS-induced colitis (3.5% DSS solution; 7 d), 8 mice with chronic DSS-induced colitis (3.5% DSS solution for 5 d + water for 6 d; 4 cycles; total: 44 d) and 12 mice without DSS supplementation as a control group. Primary colonic epithelial cells were isolated using chelation method. The cells were cultivated in the presence of mediators (lipopolysaccharide (LPS), apocynin or diphenyleneiodonium). Viability of cells was assessed by fluorescent microscopy. Production of reactive oxygen species (ROS) by the cells was measured fluorometrically using Amplex Red. Production of tumour necrosis factor-alpha (TNF-?) by the colonic epithelial cells was analysed by ELISA. Nox1 gene expression was assessed by real-time PCR. RESULTS: Our study showed that TNF-? level was increased in unstimulated primary colonic cells both in the acute and chronic colitis groups, whereas decreased viability, increased ROS production, and expression of Nox1 was characteristic only for chronic DSS colitis mice when compared to the controls. The stimulation by LPS increased ROS generation via NADPH oxidase and decreased cell viability in mice with acute colitis. Treatment with NADPH oxidase inhibitors increased cell viability and decreased the levels of ROS and TNF-? in the LPS-treated cells isolated from mice of both acute and chronic colitis groups. CONCLUSION: Our study revealed the importance of NADPH oxidase in the pathogenesis of both acute and chronic inflammation of the colon. PMID:25253955