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Sample records for acid dioxygenase hpd

  1. Hourly Precipitation Data (HPD) Publication

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hourly Precipitation Data (HPD) Publication is archived and available from the National Climatic Data Center (NCDC). This publication contains hourly precipitation...

  2. Function of different amino acid residues in the reaction mechanism of gentisate 1,2-dioxygenases deduced from the analysis of mutants of the salicylate 1,2-dioxygenase from Pseudaminobacter salicylatoxidans.

    Science.gov (United States)

    Eppinger, Erik; Ferraroni, Marta; Bürger, Sibylle; Steimer, Lenz; Peng, Grace; Briganti, Fabrizio; Stolz, Andreas

    2015-10-01

    The genome of the α-proteobacterium Pseudaminobacter salicylatoxidans codes for a ferrous iron containing ring-fission dioxygenase which catalyzes the 1,2-cleavage of (substituted) salicylate(s), gentisate (2,5-dihydroxybenzoate), and 1-hydroxy-2-naphthoate. Sequence alignments suggested that the "salicylate 1,2-dioxygenase" (SDO) from this strain is homologous to gentisate 1,2-dioxygenases found in bacteria, archaea and fungi. In the present study the catalytic mechanism of the SDO and gentisate 1,2-dioxygenases in general was analyzed based on sequence alignments, mutational and previously performed crystallographic studies and mechanistic comparisons with "extradiol- dioxygenases" which cleave aromatic nuclei in the 2,3-position. Different highly conserved amino acid residues that were supposed to take part in binding and activation of the organic substrates were modified in the SDO by site-specific mutagenesis and the enzyme variants subsequently analyzed for the conversion of salicylate, gentisate and 1-hydroxy-2-naphthoate. The analysis of enzyme variants which carried exchanges in the positions Arg83, Trp104, Gly106, Gln108, Arg127, His162 and Asp174 demonstrated that Arg83 and Arg127 were indispensable for enzymatic activity. In contrast, residual activities were found for variants carrying mutations in the residues Trp104, Gly106, Gln108, His162, and Asp174 and some of these mutants still could oxidize gentisate, but lost the ability to convert salicylate. The results were used to suggest a general reaction mechanism for gentisate-1,2-dioxygenases and to assign to certain amino acid residues in the active site specific functions in the cleavage of (substituted) salicylate(s). Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Purification and properties of protocatechuate 3,4-dioxygenase from Chaetomium piluliferum induced with p-hydroxybenzoic acid.

    Science.gov (United States)

    Wojtaś-Wasilewska, M; Trojanowski, J

    1980-01-01

    1. Protocatechuate 3,4-dioxygenase (protocatechuate : oxygen 3,4-oxidoreductase, EC 1.13.11.3) was isolated from mycelium of Chaetomium piluliferum induced with p-hydroxybenzoic acid. The enzyme was purified about 80-fold by ammonium sulphate fractionation and DEAE-cellulose and Sephadex G-200 chromatography, and was homogeneous on polyacrylamide-gel electrophoresis. 2. The enzyme showed high substrate specificity; its pH optimum was 7.5-8.0, and molecula weight about 76 000 as determined by filtration on Sephadex G-200. The Michaelis constant for protocatechuic acid was 11.1 microM.

  4. Phenylpropanoid 2,3-dioxygenase involved in the cleavage of the ferulic acid side chain to form vanillin and glyoxylic acid in Vanilla planifolia.

    Science.gov (United States)

    Negishi, Osamu; Negishi, Yukiko

    2017-09-01

    Enzyme catalyzing the cleavage of the phenylpropanoid side chain was partially purified by ion exchange and gel filtration column chromatography after (NH 4 ) 2 SO 4 precipitation. Enzyme activities were dependent on the concentration of dithiothreitol (DTT) or glutathione (GSH) and activated by addition of 0.5 mM Fe 2+ . Enzyme activity for ferulic acid was as high as for 4-coumaric acid in the presence of GSH, suggesting that GSH acts as an endogenous reductant in vanillin biosynthesis. Analyses of the enzymatic reaction products with quantitative NMR (qNMR) indicated that an amount of glyoxylic acid (GA) proportional to vanillin was released from ferulic acid by the enzymatic reaction. These results suggest that phenylpropanoid 2,3-dioxygenase is involved in the cleavage of the ferulic acid side chain to form vanillin and GA in Vanilla planifolia.

  5. P-HYDROXYPHENYLPYRUVATE DIOXYGENASE from Medicago sativa is involved in vitamin E biosynthesis and abscisic acid-mediated seed germination

    Science.gov (United States)

    Jiang, Jishan; Chen, Zhihong; Ban, Liping; Wu, Yudi; Huang, Jianping; Chu, Jinfang; Fang, Shuang; Wang, Zan; Gao, Hongwen; Wang, Xuemin

    2017-01-01

    P-HYDROXYPHENYLPYRUVATE DIOXYGENASE (HPPD) is the first committed enzyme involved in the biosynthesis of vitamin E, and is characterized by catalyzing the conversion of p-hydroxyphenyl pyruvate (HPP) to homogentisic acid (HGA). Here, an HPPD gene was cloned from Medicago sativa L. and designated MsHPPD, which was expressed at high levels in alfalfa leaves. PEG 6000 (polyethylene glycol), NaCl, abscisic acid and salicylic acid were shown to significantly induce MsHPPD expression, especially in the cotyledons and root tissues. Overexpression of MsHPPD was found to significantly increase the level of β-tocotrienol and the total vitamin E content in Arabidopsis seeds. Furthermore, these transgenic Arabidopsis seeds exhibited an accelerated germination time, compared with wild-type seeds under normal conditions, as well as under NaCl and ABA treatments. Meanwhile, the expression level of several genes associated with ABA biosynthesis (NCED3, NCED5 and NCED9) and the ABA signaling pathway (RAB18, ABI3 and ABI5) were significantly down-regulated in MsHPPD-overexpressing transgenic lines, as well as the total free ABA content. Taken together, these results demonstrate that MsHPPD functions not only in the vitamin E biosynthetic pathway, but also plays a critical role in seed germination via affecting ABA biosynthesis and signaling. PMID:28084442

  6. P-HYDROXYPHENYLPYRUVATE DIOXYGENASE from Medicago sativa is involved in vitamin E biosynthesis and abscisic acid-mediated seed germination.

    Science.gov (United States)

    Jiang, Jishan; Chen, Zhihong; Ban, Liping; Wu, Yudi; Huang, Jianping; Chu, Jinfang; Fang, Shuang; Wang, Zan; Gao, Hongwen; Wang, Xuemin

    2017-01-13

    P-HYDROXYPHENYLPYRUVATE DIOXYGENASE (HPPD) is the first committed enzyme involved in the biosynthesis of vitamin E, and is characterized by catalyzing the conversion of p-hydroxyphenyl pyruvate (HPP) to homogentisic acid (HGA). Here, an HPPD gene was cloned from Medicago sativa L. and designated MsHPPD, which was expressed at high levels in alfalfa leaves. PEG 6000 (polyethylene glycol), NaCl, abscisic acid and salicylic acid were shown to significantly induce MsHPPD expression, especially in the cotyledons and root tissues. Overexpression of MsHPPD was found to significantly increase the level of β-tocotrienol and the total vitamin E content in Arabidopsis seeds. Furthermore, these transgenic Arabidopsis seeds exhibited an accelerated germination time, compared with wild-type seeds under normal conditions, as well as under NaCl and ABA treatments. Meanwhile, the expression level of several genes associated with ABA biosynthesis (NCED3, NCED5 and NCED9) and the ABA signaling pathway (RAB18, ABI3 and ABI5) were significantly down-regulated in MsHPPD-overexpressing transgenic lines, as well as the total free ABA content. Taken together, these results demonstrate that MsHPPD functions not only in the vitamin E biosynthetic pathway, but also plays a critical role in seed germination via affecting ABA biosynthesis and signaling.

  7. Eucalyptus ESTs involved in the production of 9-cis epoxycarotenoid dioxygenase, a regulatory enzyme of abscisic acid production

    Directory of Open Access Journals (Sweden)

    Iraê A. Guerrini

    2005-01-01

    Full Text Available Abscisic acid (ABA regulates stress responses in plants, and genomic tools can help us to understand the mechanisms involved in that process. FAPESP, a Brazilian research foundation, in association with four private forestry companies, has established the FORESTs database (https://forests.esalq.usp.br. A search was carried out in the Eucalyptus expressed sequence tag database to find ESTs involved with 9-cis epoxycarotenoid dioxygenase (NCED, the regulatory enzyme for ABA biosynthesis, using the basic local BLAST alignment tool. We found four clusters (EGEZLV2206B11.g, EGJMWD2252H08.g, EGBFRT3107F10.g, and EGEQFB1200H10.g, which represent similar sequences of the gene that produces NCED. Data showed that the EGBFRT3107F10.g cluster was similar to the maize (Zea mays NCED enzyme, while EGEZLV2206B11.g and EGJMWD2252H08.g clusters were similar to the avocado (Persea americana NCED enzyme. All Eucalyptus clusters were expressed in several tissues, especially in flower buds, where ABA has a special participation during the floral development process.

  8. Bubble chamber film exposure for measurement by HPD

    International Nuclear Information System (INIS)

    Oxley, A.J.

    1978-03-01

    It is not easy for HPD measuring machines to detect tracks of low contrast in film from bubble chambers with bright-field illumination. Some of the basic aspects and limitations are considered in this paper. (author)

  9. 3-Sulphocatechol 2,3-dioxygenase and other dioxygenases (EC 1.13.11.2 and EC 1.14.12.-) in the degradative pathways of 2-aminobenzenesulphonic, benzenesulphonic and 4-toluenesulphonic acids in Alcaligenes sp. strain O-1.

    Science.gov (United States)

    Junker, F; Leisinger, T; Cook, A M

    1994-07-01

    Alcaligenes sp. strain O-1 utilizes three sulphonated aromatic compounds as sole sources of carbon and energy for growth in minimal salts medium-benzenesulphonate (BS), 4-toluenesulphonate (TS) and 2-aminobenzenesulphonate (2AS). The degradative pathway(s) in 2AS-grown cells are initiated with membrane transport, NADH-dependent dioxygenation and meta ring cleavage. The specific activity of the NADH-dependent dioxygenation(s) varied with the growth phase and was maximal near the end of exponential growth for each growth substrate. Cells were harvested at this point from BS-, TS- and 2AS-salts medium. Cells grown with each sulphonated substrate could oxygenate all three compounds, but only 2AS-grown cells consumed 2 mol O2 per mol 2AS or BS or TS. BS- and TS-grown cells consumed 2 mol O2 per mol BS or TS but failed to oxygenate the product of oxygenation of 2AS, 3-sulphocatechol (3SC). These observations were repeated with cell extracts and we concluded that there were two sets of desulphonative pathways in the organism, one for 2AS and one for BS and TS. We confirmed this hypothesis by separating the degradative enzymes from 2AS-, BS- or TS-grown cells. A 2AS dioxygenase system and a 3SC-2,3-dioxygenase (3SC23O) were detected in 2AS-grown cells only. In both BS- and TS-grown cells a dioxygenase system for BS and TS was observed as well as a principal catechol 2,3-dioxygenase (C23O-III), neither of which was present in 2AS-grown cells. The 3SC23O was purified to near homogeneity, found to be monomeric (M(r) 42,000), and to catalyse 2,3-dioxygenation to a product that decayed spontaneously to sulphite and 2-hydroxymuconate. The 2AS dioxygenase system could cause not only deamination of 2AS but also desulphonation of BS and TS. The BS dioxygenase could desulphonate BS and apparently either desulphonate or deaminate 2AS. Strain O-1 thus seems to contain two putative, independently regulated operons involving oxygenation and spontaneous desulphonation(s). One operon

  10. Two members of the CERN HPD team present their babies. André Braem (left) holds in his hands a 5-inch glass HPD, while a ceramic HPD for medical applications is shown by Christian Joram. The large detector in the middle is a 10-inch HPD developed for an astrophysics experiment.

    CERN Multimedia

    Maximilien Brice

    2004-01-01

    Two members of the CERN HPD team present their babies. André Braem (left) holds in his hands a 5-inch glass HPD, while a ceramic HPD for medical applications is shown by Christian Joram. The large detector in the middle is a 10-inch HPD developed for an astrophysics experiment.

  11. Design, fabrication and performance of the 10-in TOM HPD

    CERN Document Server

    Braem, André; Joram, C; Séguinot, Jacques; Weilhammer, P; Giunta, M; Malakhov, N; Menzione, A; Pegna, R; Piccioli, A; Raffaelli, F; Sartori, G

    2004-01-01

    The first sealed TOM Hybrid Photon Detector (HPD) with 10-in. diameter has been fabricated and successfully tested at CERN. This HPD has a spherical entrance window and a bialkali photocathode. The fountain focusing optics produces a demagnified image (D = 4) on the round segmented silicon sensor. The signals of the 2048 cells are read out through analog front-end electronics encapsulated in the vacuum envelope. We report on the design, fabrication technique and the experimental results obtained with laboratory test benches. The large TOM HPD is a prototype tube developed for the CLUE cosmic ray experiment. The final tubes, now under development, will be equipped with a solar-blind Rb//2Te photocathode and self triggering front-end electronics.

  12. The AlkB Family of Fe(II)/α-Ketoglutarate-dependent Dioxygenases: Repairing Nucleic Acid Alkylation Damage and Beyond.

    Science.gov (United States)

    Fedeles, Bogdan I; Singh, Vipender; Delaney, James C; Li, Deyu; Essigmann, John M

    2015-08-21

    The AlkB family of Fe(II)- and α-ketoglutarate-dependent dioxygenases is a class of ubiquitous direct reversal DNA repair enzymes that remove alkyl adducts from nucleobases by oxidative dealkylation. The prototypical and homonymous family member is an Escherichia coli "adaptive response" protein that protects the bacterial genome against alkylation damage. AlkB has a wide variety of substrates, including monoalkyl and exocyclic bridged adducts. Nine mammalian AlkB homologs exist (ALKBH1-8, FTO), but only a subset functions as DNA/RNA repair enzymes. This minireview presents an overview of the AlkB proteins including recent data on homologs, structural features, substrate specificities, and experimental strategies for studying DNA repair by AlkB family proteins. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  13. Metabolism and Residues of 2,4-Dichlorophenoxyacetic Acid in DAS-40278-9 Maize (Zea mays) Transformed with Aryloxyalkanoate Dioxygenase-1 Gene.

    Science.gov (United States)

    Zhou, Xiao; Rotondaro, Sandra L; Ma, Mingming; Rosser, Steve W; Olberding, Ed L; Wendelburg, Brian M; Adelfinskaya, Yelena A; Balcer, Jesse L; Blewett, T Craig; Clements, Bruce

    2016-10-12

    DAS-40278-9 maize, which is developed by Dow AgroSciences, has been genetically modified to express the aryloxyalkanoate dioxygenase-1 (AAD-1) protein and is tolerant to phenoxy auxin herbicides, such as 2,4-dichlorophenoxyacetic acid (2,4-D). To understand the metabolic route and residue distribution of 2,4-D in DAS-40278-9 maize, a metabolism study was conducted with 14 C-radiolabeled 2,4-D applied at the maximum seasonal rate. Plants were grown in boxes outdoors. Forage and mature grain, cobs, and stover were collected for analysis. The metabolism study showed that 2,4-D was metabolized to 2,4-dichlorophenol (2,4-DCP), which was then rapidly conjugated with glucose. Field-scale residue studies with 2,4-D applied at the maximum seasonal rate were conducted at 25 sites in the U.S. and Canada to measure the residues of 2,4-D and free and conjugated 2,4-DCP in mature forage, grain, and stover. Residues of 2,4-D were not detectable in the majority of the grain samples and averaged <1.0 and <1.5 μg/g in forage and stover, respectively. Free plus conjugated 2,4-DCP was not observed in grain and averaged <1.0 μg/g in forage and stover.

  14. The metabolism of L-tryptophan by isolated rat liver cells. Effect of albumin binding and amino acid competition on oxidatin of tryptophan by tryptophan 2,3-dioxygenase.

    OpenAIRE

    Smith, S A; Pogson, C I

    1980-01-01

    1. Novel methods, using L-[ring-2-14C]tryptophan, are described for the measurement of tryptophan 2,3-dioxygenase activity and tryptophan accumulation in isolated rat liver cells. 2. The effects of bovine serum albumin, non-esterified fatty acids and neutral amino acids on tryptophan oxidation by hepatocytes and on the partition of tryptophan between free and albumin-bound forms were investigated. 3. Oxidation of physiological concentrations (0.1 mM) of tryptophan was inhibited by approx. 50%...

  15. Role of dioxygenase α-DOX2 and SA in basal response and in hexanoic acid-induced resistance of tomato (Solanum lycopersicum) plants against Botrytis cinerea.

    Science.gov (United States)

    Angulo, Carlos; de la O Leyva, María; Finiti, Ivan; López-Cruz, Jaime; Fernández-Crespo, Emma; García-Agustín, Pilar; González-Bosch, Carmen

    2015-03-01

    Resistance of tomato (Solanum Lycopersicum) to the fungal pathogen Botrytis cinerea requires complex interplay between hormonal signalling. In this study, we explored the involvement of new oxylipins in the tomato basal and induced response to this necrotroph through the functional analysis of the tomato α-dioxygenase2 (α-DOX2)-deficient mutant divaricata. We also investigated the role of SA in the defence response against this necrotrophic fungus using SA-deficient tomato nahG plants. The plants lacking dioxigenase α-DOX2, which catalyses oxylipins production from fatty acids, were more susceptible to Botrytis, and hexanoic acid-induced resistance (Hx-IR) was impaired; hence α-DOX2 is required for both tomato defence and the enhanced protection conferred by natural inducer hexanoic acid (Hx) against B. cinerea. The divaricata plants accumulated less pathogen-induced callose and presented lower levels of jasmonic acid (JA) and 12-oxo-phytodienoic acid (OPDA) upon infection if compared to the wild type. Glutathion-S-transferase (GST) gene expression decreased and ROS production significantly increased in Botrytis-infected divaricata plants. These results indicate that absence of α-DOX2 influences the hormonal changes, oxidative burst and callose deposition that occur upon Botrytis infection in tomato. The study of SA-deficient nahG tomato plants showed that the plants with low SA levels displayed increased resistance to Botrytis, but were unable to display Hx-IR. This supports the involvement of SA in Hx-IR. NaghG plants displayed reduced callose and ROS accumulation upon infection and an increased GST expression. This reflects a positive relationship between SA and these defensive mechanisms in tomato. Finally, Hx boosted the pathogen-induced callose in nahG plants, suggesting that this priming mechanism is SA-independent. Our results support the involvement of the oxylipins pathway and SA in tomato response to Botrytis, probably through complex crosstalk of

  16. The Pad HPD as photodetector of the LHCb RICH detectors

    CERN Document Server

    Braem, André; Filthaut, F; Go, A; Joram, C; Séguinot, Jacques; Weilhammer, Peter; Ypsilantis, Thomas

    2001-01-01

    This document is a proposal to equip the LHCb RICH detectors with Pad HPDs as photodetectors. The Pad HPD has been developed "in-house" at CERN. It is a five inch vacuum tube with bialkali cathode and segmented silicon anode, incorporating 2048 anode pads, each connected to analogue readout electronics, encapsulated within the vacuum envelope. The design of the baseline option is described. Results of R&D using measurements in laboratory and test beam are described. The future R&D programme and the detector costs and production schedule are outlined.

  17. Measurement of the Photoelectron Detection Efficiency of the HPD Anode

    CERN Document Server

    Carson, L; Soler, P

    2009-01-01

    This paper reports on measurements carried out on the Hybrid Photon Detectors (HPDs) of the LHCb RICH detectors. The purpose of these tests is to determine the photoelectron detection efficiency $\\eta$ of the HPD anode. Knowledge of $\\eta$ is required for an accurate simulation of the RICH detectors. It is found that this efficiency is $(93.3\\pm0.7)\\%$ for a 50 ns digital readout window, and $(87.9\\pm1.4)\\%$ for a 25 ns digital readout window. The 25 ns result exceeds the LHCb-RICH requirement of 85\\%, and is in agreement both with direct $\\eta$ measurements using preseries HPDs, and with indirect measurements from testbeams using preseries and production HPDs.

  18. Indoleamine 2,3-dioxygenase, by degrading L-tryptophan, enhances carnitine palmitoyltransferase I activity and fatty acid oxidation, and exerts fatty acid-dependent effects in human alloreactive CD4+ T-cells.

    Science.gov (United States)

    Eleftheriadis, Theodoros; Pissas, Georgios; Sounidaki, Maria; Tsogka, Konstantina; Antoniadis, Nikolaos; Antoniadi, Georgia; Liakopoulos, Vassilios; Stefanidis, Ioannis

    2016-11-01

    Indoleamine 2,3-dioxygenase (IDO) is expressed in antigen-presenting cells and by degrading L-tryptophan along the kynurenine pathway suppresses CD4+ T-cell proliferation, induces apoptosis and promotes differentiation towards a regulatory as opposed to an effector phenotype. Recent findings revealed that the above effects may be mediated through alterations in T-cell metabolism. In this study, the effect of IDO on fatty acid β-oxidation in CD4+ T-cells was evaluated in human mixed lymphocyte reactions (MLRs) using the IDO inhibitor, 1-DL-methyl-tryptophan. Protein analysis of CD4+ T-cells isolated from the MLR showed that L-tryptophan degradation acts by activating the general control non‑derepressible 2 kinase and aryl-hydrocarbon receptor in T-cells. In the absence of IDO inhibition, fatty acid oxidation increased along with increased activity of carnitine palmitoyltransferase I (CPT1), the latter due to the increased expression of CPT1 isoenzymes and alterations in acetyl-CoA carboxylase 2, the enzyme that controls CPT1 activity. Increased fatty acid oxidation due to the action of IDO was accompanied by an increased expression of forkhead box P3 (FoxP3) and a decreased expression of related orphan receptor γt (RORγt), the signature transcription factors of regulatory T-cells and T helper 17 cells, respectively. However, in MLR and in the presence of fatty acid in the culture medium, IDO did not inhibit proliferation. Additionally, fatty acid protected the CD4+ T-cells against apoptosis. Thus, IDO, by degrading L-tryptophan, enhances CPT1 activity and fatty acid oxidation, and exerts fatty acid-dependent effects in human alloreactive CD4+ T-cells.

  19. EPR characterization of the mononuclear Cu-containing Aspergillus japonicus quercetin 2,3-dioxygenase reveals dramatic changes upon anaerobic binding of substrates

    NARCIS (Netherlands)

    Kooter, Ingeborg M.; Steiner, Roberto A.; Dijkstra, Bauke W.; Noort, Paula I. van; Egmond, Maarten R.; Huber, Martina

    Quercetin 2,3-dioxygenase (2,3QD) is a copper-containing dioxygenase that catalyses the oxidation of the flavonol quercetin to 2-protocatechuoylphloroglucinol carboxylic acid with concomitant production of carbon monoxide. In contrast to iron dioxygenases, very little is known about copper

  20. Extensive tests of Hybrid Photon Detectors (HPD) used to collect Cherenkov light

    International Nuclear Information System (INIS)

    Borsato, E.; Buccheri, A.; DalCorso, F.; Ferroni, F.; Iacovella, F.; Mazzoni, M.A.; Morandin, M.; Morganti, S.; Piredda, G.; Posocco, M.; Santacesaria, R.; Stroili, R.; Torassa, E.; Voci, C.

    1997-01-01

    The principle of operation of a newly developed proximity focused Hybrid Photon Detector is described. The HPD characteristics, performance and calibration are reported. Results from beam tests of aerogel threshold counters read out by HPD and the particle identification performance are presented. (orig.)

  1. Review of the hybrid photo diode tube (HPD) an advanced light detector for physics

    International Nuclear Information System (INIS)

    Anzivino, G.; Baillon, P.; Benetti, P.; Boskma, L.; Burger, P.; Contin, A.; DeSalvo, R.; Gorodetzky, P.; Grassi, D.; Hao, W.; He, H.; Liu, L.; Lundin, M.; Mondardini, M.R.; Paolucci, S.; Rossella, M.; Santiard, J.C.; Schomaker, R.; You, K.; Wang, K.; Wang, Y.; Xia, X.; Xu, C.; Yang, C.; Zhao, M.

    1995-01-01

    The HPD is a nonmultiplicative light detector with typical gain of 1000 to 5000. Its development project, mainly supported by the CERN LAA project and by the INFN group V, was originally intended to find a replacement for the photo multiplier (PM) tubes for scintillating fibre calorimeter readout. After five years of development the HPD has become a versatile light detector, commercially available for everyday use, that can outperform PM tubes in photon counting efficiency and resolution, multi tesla magnetic field operation, uniformity of response, fast pulse dynamic range, and gain stability. The HPD has also a wide edge on PMs on pixelization potential and it is getting more and more competitive on timing properties. A review of the HPD performances and its latest advances are reported. (orig.)

  2. Review of the hybrid photo diode tube (HPD) an advanced light detector for physics

    Energy Technology Data Exchange (ETDEWEB)

    Anzivino, G. [Istituto Nazionale di Fisica Nucleare, Frascati (Italy). Lab. Nazionale di Frascati; Arnaudon, H. [Universite` L. Pasteur, 4, rue B. Pascal, F-67000 Strasbourg (France); Baillon, P. [CERN, CH-1211 Geneva 23 (Switzerland); Benetti, P. [INFN Sezione di Pavia and Universita` di Pavia, via A. Bassi 6, I-27100 Pavia (Italy); Boskma, L. [DEP, P.O. box 60, NL-9300 AB Roden (Netherlands); Burger, P. [Canberra, Lammerdries 25, B-2250 Olen (Belgium); Contin, A. [CERN, CH-1211 Geneva 23 (Switzerland)]|[INFN Sezione di Bologna and Universita` di Bologna, via Irnerio 46, I-40126 Bologna (Italy); DeSalvo, R. [CERN, CH-1211 Geneva 23 (Switzerland); Gorodetzky, P. [CNRS, Strasbourg (France); Grassi, D. [INFN Sezione di Pavia and Universita` di Pavia, via A. Bassi 6, I-27100 Pavia (Italy); Hao, W. [IHEP, Beijing (China); He, H. [IHEP, Beijing (China); Liu, L. [IHEP, Beijing (China); Lundin, M. [Cornell University, Ithaca, NY 14853 (United States); Mondardini, M.R. [Cornell University, Ithaca, NY 14853 (United States); Paolucci, S. [INFN Sezione di Pavia and Universita` di Pavia, via A. Bassi 6, I-27100 Pavia (Italy); Rossella, M. [INFN Sezione di Pavia and Universita` di Pavia, via A. Bassi 6, I-27100 Pavia (Italy); Santiard, J.C. [CERN, CH-1211 Geneva 23 (Switzerland); Schomaker, R. [DEP, P.O. box 60, NL-9300 AB Roden (Netherlands); You, K. [IHEP, Beijing (China); Wang, K. [IHEP, Beijing (China); Wang, Y. [IHEP, Beijing (China); Xia, X. [IHEP, Beijing (China); Xu, C. [IHEP, Beijing (China); Yang, C. [IHEP, Beijing (China); Zhao, M. [IHEP, Beijing (China)

    1995-11-01

    The HPD is a nonmultiplicative light detector with typical gain of 1000 to 5000. Its development project, mainly supported by the CERN LAA project and by the INFN group V, was originally intended to find a replacement for the photo multiplier (PM) tubes for scintillating fibre calorimeter readout. After five years of development the HPD has become a versatile light detector, commercially available for everyday use, that can outperform PM tubes in photon counting efficiency and resolution, multi tesla magnetic field operation, uniformity of response, fast pulse dynamic range, and gain stability. The HPD has also a wide edge on PMs on pixelization potential and it is getting more and more competitive on timing properties. A review of the HPD performances and its latest advances are reported. (orig.).

  3. Biochemical analysis of Phytolacca DOPA dioxygenase.

    Science.gov (United States)

    Takahashi, Kana; Yoshida, Kazuko; Yura, Kei; Ashihara, Hiroshi; Sakuta, Masaaki

    2015-05-01

    The biochemical analysis of Phytolacca americana DOPA dioxygenases (PaDOD1 and PaDOD2) was carried out. The recombinant protein of PaDOD1 catalyzed the conversion of DOPA to betalamic acid, whereas DOD activity was not detected in PaDOD2 in vitro. While the reported motif conserved in DODs from betalain-producing plants was found in PaDOD1, a single amino acid residue alteration was detected in PaDOD2. A mutated PaDOD1 protein with a change of 177 Asn to Gly showed reduced specific activity compared with PaDOD1, while DOPA dioxygenase activity was not observed for a mutated PaDOD2 protein which had its conserved motif replaced with that of PaDOD. A three-dimensional (3D) structural model of PaDOD1 and PaDOD2 showed that the conserved motif in DODs was located in the N-terminal side of a loop, which was found close to the putative active site. The difference in stability of the loop may affect the enzymatic activity of PaDOD2.

  4. Band structure analysis of (1 × 2)-H/Pd(110)-pr

    Science.gov (United States)

    Shuttleworth, I. G.

    2013-09-01

    A novel method of band structure analysis based on the atomic orbital (AO) coefficients in LCAO-DFT has been applied to the (1 × 2)-H/Pd(110)-pr system. The analysis has revealed symmetry-dependent Pd 4d band splitting due to H ligand effects; ensemble effects due to the (1 × 2) Pd reconstruction are shown to be relatively minor.

  5. Tuning biphenyl dioxygenase for extended substrate specificity

    Energy Technology Data Exchange (ETDEWEB)

    Bruehlmann, F.; Chen, W. [Univ. of California, Riverside, CA (United States). Dept. of Chemical and Environmental Engineering

    1999-06-05

    Highly substituted polychlorinated biphenyls (PCBs) are known to be very resistant to aerobic biodegradation, particularly the initial attack by biphenyl dioxygenase. Functional evolution of the substrate specificity of biphenyl dioxygenase was demonstrated by DNA shuffling and staggered extension process (StEP) of the bphA gene coding for the large subunit of biphenyl dioxygenase. Several variants with an extended substrate range for PCBs were selected. In contrast to the parental biphenyl dioxygenases from Burkholderia cepacia LB400 and Pseudomonas pseudoalcaligenes KF707, which preferentially recognize either ortho-(LB400) or para-(KF707) substituted PCBs, several variants degraded both congeners to about the same extent. These variants also exhibited superior degradation capabilities toward several tetra- and pentachlorinated PCBs as well as commercial PCB mixtures, such as Aroclor 1242 or Aroclor 1254. Sequence analysis confirmed that most variants contained at least four to six template switches. All desired variants contained the Thr335Ala and Phe336lle substitutions confirming the importance of this critical region in substrate specificity. These results suggest that the block-exchange nature of gene shuffling between a diverse class of dioxygenases may be the most useful approach for breeding novel dioxygenases for PCB degradation in the desired direction.

  6. Hilbert phase dynamometry (HPD) for real-time measurement of cell generated forces (Conference Presentation)

    Science.gov (United States)

    Sridharan, Shamira; Li, Yanfen; Bhaduri, Basanta; Majeed, Hassaan; Dupenloup, Paul; Levine, Alex; Kilian, Kristopher A.; Popescu, Gabriel

    2016-03-01

    Traction force microscopy is the most widely used technique for studying the forces exerted by cells on deformable substrates. However, the method is computationally intense and cells have to be detached from the substrate prior to measuring the displacement map. We have developed a new method, referred to as Hilbert phase dynamometry (HPD), which yields real-time force fields and, simultaneously, cell dry mass and growth information. HPD operates by imaging cells on a deformable substrate that is patterned with a grid of fluorescent proteins. A Hilbert transform is used to extract the phase map associated with the grid deformation, which provides the displacement field. By combining this information with substrate stiffness, an elasticity model was developed to measure forces exerted by cells with high spatial resolution. In our study, we prepared 10kPa gels and them with a 2-D grid of FITC-conjugated fibrinogen/fibronectin mixture, an extracellular matrix protein to which cells adhere. We cultured undifferentiated mesenchymal stem cells (MSC), and MSCs that were in the process of undergoing adipogenesis and osteogenesis. The cells were measured over the course of 24 hours using Spatial Light Interference Microscopy (SLIM) and wide-field epi-fluorescence microscopy allowing us to simultaneously measure cell growth and the forces exerted by the cells on the substrate.

  7. The X-HPD-A modern implementation of a SMART concept

    International Nuclear Information System (INIS)

    Braem, Andre; Joram, Christian; Seguinot, Jacques; Solevi, Paola; Pierre, Leo

    2009-01-01

    The concept of hybrid photodetectors which combine a large area photocathode with a crystal scintillator anode in the centre of a hemispherical vacuum tube was demonstrated first with the Philips SMART tubes and, more recently, with the QUASAR tubes of the Lake Baikal experiment. Photoelectrons from the cathode are accelerated by a potential difference of 20-30 kV and deposit their kinetic energy in the scintillator (or Phosphor). The generated scintillation light is detected by a small and low cost photodetector, e.g. a conventional PMT. The X-HPD study is a variation of this concept aiming at improved performance and maximum simplicity. The glass envelope is essentially spherical and a spatial scintillator crystal is mounted in its centre. The spherical symmetry leads to a uniform collection efficiency and very small intrinsic time spread over the full viewing angle of 120 deg. (3π solid angle). We report about test results of a the first X-HPD prototypes of 208 mm diameter with cylindrical and conical LYSO crystal anodes.

  8. Characterization of oxylipins and dioxygenase genes in the asexual fungus Aspergillus niger

    Directory of Open Access Journals (Sweden)

    Kalkhove Stefanie IC

    2009-03-01

    Full Text Available Abstract Background Aspergillus niger is an ascomycetous fungus that is known to reproduce through asexual spores, only. Interestingly, recent genome analysis of A. niger has revealed the presence of a full complement of functional genes related to sexual reproduction 1. An example of such genes are the dioxygenase genes which in Aspergillus nidulans, have been shown to be connected to oxylipin production and regulation of both sexual and asexual sporulation 234. Nevertheless, the presence of sex related genes alone does not confirm sexual sporulation in A. niger. Results The current study shows experimentally that A. niger produces the oxylipins 8,11-dihydroxy octadecadienoic acid (8,11-diHOD, 5,8-dihydroxy octadecadienoic acid (5,8-diHOD, lactonized 5,8-diHOD, 8-hydroxy octadecadienoic acid (8-HOD, 10-hydroxy octadecadienoic acid (10-HOD, small amounts of 8-hydroxy octadecamonoenoic acid (8-HOM, 9-hydroxy octadecadienoic acid (9-HOD and 13-hydroxy octadecadienoic acid (13-HOD. Importantly, this study shows that the A. niger genome contains three putative dioxygenase genes, ppoA, ppoC and ppoD. Expression analysis confirmed that all three genes are indeed expressed under the conditions tested. Conclusion A. niger produces the same oxylipins and has similar dioxygenase genes as A. nidulans. Their presence could point towards the existence of sexual reproduction in A. niger or a broader role for the gene products in physiology, than just sexual development.

  9. 4-Hydroxyphenylpyruvate Dioxygenase Inhibitors: From Chemical Biology to Agrochemicals.

    Science.gov (United States)

    Ndikuryayo, Ferdinand; Moosavi, Behrooz; Yang, Wen-Chao; Yang, Guang-Fu

    2017-10-04

    The development of new herbicides is receiving considerable attention to control weed biotypes resistant to current herbicides. Consequently, new enzymes are always desired as targets for herbicide discovery. 4-Hydroxyphenylpyruvate dioxygenase (HPPD, EC 1.13.11.27) is an enzyme engaged in photosynthetic activity and catalyzes the transformation of 4-hydroxyphenylpyruvic acid (HPPA) into homogentisic acid (HGA). HPPD inhibitors constitute a promising area of discovery and development of innovative herbicides with some advantages, including excellent crop selectivity, low application rates, and broad-spectrum weed control. HPPD inhibitors have been investigated for agrochemical interests, and some of them have already been commercialized as herbicides. In this review, we mainly focus on the chemical biology of HPPD, discovery of new potential inhibitors, and strategies for engineering transgenic crops resistant to current HPPD-inhibiting herbicides. The conclusion raises some relevant gaps for future research directions.

  10. Indoleamine 2,3-dioxygenase vaccination

    DEFF Research Database (Denmark)

    Andersen, Mads Hald; Svane, Inge Marie

    2015-01-01

    Indoleamine 2,3-dioxygenase (IDO) is an immunoregulatory enzyme. Remarkably, we discovered IDO-specific T cells that can influence adaptive immune reactions in patients with cancer. Further, a recent phase I clinical trial demonstrated long-lasting disease stabilization without toxicity in patien...... with non-small-cell lung cancer (NSCLC) who were vaccinated with an IDO-derived HLA-A2-restricted epitope....

  11. Identification of metabolites from phenanthrene oxidation by phenoloxidases and dioxygenases of Polyporus sp. S133.

    Science.gov (United States)

    Hadibarata, Tony; Tachibana, Sanro; Askari, Muhamad

    2011-03-01

    Phenanthrene degradation by Polyporus sp. S133, a new phenanthrene-degrading strain, was investigated in this work. The analysis of degradation was performed by calculation of the remaining phenanthrene by gas chromatography-mass spectrometry. When cells were grown in phenanthrene culture after 92 h, all but 200 and 250 mg/l of the phenanthrene had been degraded. New metabolic pathways of phenanthrene and a better understanding of the phenoloxidases and dioxygenase mechanism involved in degradation of phenanthrene were explored in this research. The mechanism of degradation was determined through identification of the several metabolites; 9,10-phenanthrenequinone, 2,2'-diphenic acid, salicylic acid, and catechol. 9,10-Oxidation and ring cleavage to give 9,10-phenanthrenequinone is the major fate of phenanthrene in ligninolytic Polyporus sp. S133. The identification of 2,2'-diphenic acid in culture extracts indicates that phenanthrene was initially attacked through dioxigenation at C9 and C10 to give cis-9,10-dihydrodiol. Dehydrogenation of phenanthrene-cis-9,10-dihydrodiol to produce the corresponding diol, followed by ortho-cleavage of the oxygenated ring, produced 2,2'-diphenic acid. Several enzymes (manganese peroxidase, lignin peroxidase, laccase, 1,2-dioxygenase, and 2,3-dioxygenase) produced by Polyporus sp. S133 was detected during the incubation. The highest level of activity was shown at 92 h of culture.

  12. Understanding human thiol dioxygenase enzymes: structure to function, and biology to pathology.

    Science.gov (United States)

    Sarkar, Bibekananda; Kulharia, Mahesh; Mantha, Anil K

    2017-04-01

    Amino acid metabolism is a significant metabolic activity in humans, especially of sulphur-containing amino acids, methionine and cysteine (Cys). Cys is cytotoxic and neurotoxic in nature; hence, mammalian cells maintain a constant intracellular level of Cys. Metabolism of Cys is mainly regulated by two thiol dioxygenases: cysteine dioxygenase (CDO) and 2-aminoethanethiol dioxygenase (ADO). CDO and ADO are the only human thiol dioxygenases reported with a role in Cys metabolism and localized to mitochondria. This metabolic pathway is important in various human disorders, as it is responsible for the synthesis of antioxidant glutathione and is also for the synthesis of hypotaurine and taurine. CDO is the most extensively studied protein, whose high-resolution crystallographic structures have been solved. As compared to CDO, ADO is less studied, even though it has a key role in cysteamine metabolism. To further understand ADO's structure and function, the three-dimensional structures have been predicted from I-TASSER and SWISS-MODEL servers and validated with PROCHECK software. Structural superimposition approach using iPBA web server further confirmed near-identical structures (including active sites) for the predicted protein models of ADO as compared to CDO. In addition, protein-protein interaction and their association in patho-physiology are crucial in understanding protein functions. Both ADO and CDO interacting partner profiles have been presented using STRING database. In this study, we have predicted a 3D model structure for ADO and summarized the biological roles and the pathological consequences which are associated with the altered expression and functioning of ADO and CDO in case of cancer, neurodegenerative disorders and other human diseases. © 2017 The Authors. International Journal of Experimental Pathology © 2017 International Journal of Experimental Pathology.

  13. Direct Ring Fission of Salicylate by a Salicylate 1,2-Dioxygenase Activity from Pseudaminobacter salicylatoxidans

    Science.gov (United States)

    Hintner, Jan-Peter; Lechner, Christa; Riegert, Ulrich; Kuhm, Andrea Elisabeth; Storm, Thomas; Reemtsma, Thorsten; Stolz, Andreas

    2001-01-01

    In cell extracts of Pseudaminobacter salicylatoxidans strain BN12, an enzymatic activity was detected which converted salicylate in an oxygen-dependent but NAD(P)H-independent reaction to a product with an absorbance maximum at 283 nm. This metabolite was isolated, purified, and identified by mass spectrometry and 1H and 13C nuclear magnetic resonance spectroscopy as 2-oxohepta-3,5-dienedioic acid. This metabolite could be formed only by direct ring fission of salicylate by a 1,2-dioxygenase reaction. Cell extracts from P. salicylatoxidans also oxidized 5-aminosalicylate, 3-, 4-, and 5-chlorosalicylate, 3-, 4-, and 5-methylsalicylate, 3- and 5-hydroxysalicylate (gentisate), and 1-hydroxy-2-naphthoate. The dioxygenase was purified and shown to consist of four identical subunits with a molecular weight of about 45,000. The purified enzyme showed higher catalytic constants with gentisate or 1-hydroxy-2-naphthoate than with salicylate. It was therefore concluded that P. salicylatoxidans synthesized a gentisate 1,2-dioxygenase with an extraordinary substrate range, which also allowed the oxidation of salicylate. PMID:11698383

  14. Using resistivity to measure H/Pd and D/Pd loading. Method and significance

    International Nuclear Information System (INIS)

    Mckubre, M.C.H.; Tanzella, F.L.

    2006-01-01

    is now important to obtain accurate quantitative information for x close to unity. With further experimentation and analysis of published data it is apparent that the curve originally published in 1990 is in error in the high loading condition. This paper describes how this empirical fit has been improved over the years for both H/Pd and D/Pd by employing new data, new analysis of old data, new experimental methods and results. (author)

  15. Software of the mini-computer TPA-1 saving system of events measured on the HPD automation

    International Nuclear Information System (INIS)

    Zhenei, M.

    1977-01-01

    Described is the event recovery system for events measured by the HPD automatic scanner. The system contains a raster display, 256x256, with built-in the INTEL 8080 microprocessor, the TRA/1 minicomputer, and two storage disks of 512 kilobytes. Designing the recovery system on the basis of the minicomputer becomes possible due to that the recovery program is written on the ASSEMBLER lanquage and owing to that no high accuracy is required for recognizing tracks. Discussed is the software of this recovery system designed on the basis of the OS/8 operational system. The software enables the operator to participate in recognizing images of complicated events

  16. Evaluation of personal dose equivalent 'HP(d)' in a external individual monitoring system for X and gamma radiation

    International Nuclear Information System (INIS)

    Santoro, C.; Antonio Filho, J.; Santos, M.A.P.

    2007-01-01

    The good of individual monitoring for external radiation is the assessment of occupational exposure from X and γ radiations in order to assure that the radiological conditions of the workplace are acceptable, safe and satisfactory. The evaluation of radiations doses for workers must not exceed dose limits specified for workers, according to national regulatory agencies. Nowadays, there are two external monitoring systems in use, both based on ICRU definitions. In the conventional system, the workers doses are evaluated in terms of Hx. The personal dosimeter is worn over chest surface and it is calibrated in function of air kerma. In the new system, the workers doses are evaluated in terms of HP(d) and the personal dosimeter is calibrated in function of phantom doses. The aim of this paper is to adapt an external dosimetry laboratory (based on photographic dosimetry) to evaluate the personal dosimeters in terms of HP(d). In this way, a simple methodology, based on linear programming, was utilized. In this adaptation, calibration curves were obtained for radiation qualities (W and N series) described by International Organization for Standardization (ISO 4037-1, 1995). These calibration curves offer a better accuracy on dose determinations and energy below 140 keV, improving the quality of service rendered the society. (author)

  17. Structure of the 2,4'-dihydroxyacetophenone dioxygenase from Alcaligenes sp. 4HAP.

    Science.gov (United States)

    Keegan, R; Lebedev, A; Erskine, P; Guo, J; Wood, S P; Hopper, D J; Rigby, S E J; Cooper, J B

    2014-09-01

    The enzyme 2,4'-dihydroxyacetophenone dioxygenase (DAD) catalyses the conversion of 2,4'-dihydroxyacetophenone to 4-hydroxybenzoic acid and formic acid with the incorporation of molecular oxygen. Whilst the vast majority of dioxygenases cleave within the aromatic ring of the substrate, DAD is very unusual in that it is involved in C-C bond cleavage in a substituent of the aromatic ring. There is evidence that the enzyme is a homotetramer of 20.3 kDa subunits, each containing nonhaem iron, and its sequence suggests that it belongs to the cupin family of dioxygenases. In this paper, the first X-ray structure of a DAD enzyme from the Gram-negative bacterium Alcaligenes sp. 4HAP is reported, at a resolution of 2.2 Å. The structure establishes that the enzyme adopts a cupin fold, forming dimers with a pronounced hydrophobic interface between the monomers. The catalytic iron is coordinated by three histidine residues (76, 78 and 114) within a buried active-site cavity. The iron also appears to be tightly coordinated by an additional ligand which was putatively assigned as a carbonate dianion since this fits the electron density optimally, although it might also be the product formate. The modelled carbonate is located in a position which is highly likely to be occupied by the α-hydroxyketone group of the bound substrate during catalysis. Modelling of a substrate molecule in this position indicates that it will interact with many conserved amino acids in the predominantly hydrophobic active-site pocket where it undergoes peroxide radical-mediated heterolysis.

  18. Indoleamine 2,3-Dioxygenase (IDO)

    Science.gov (United States)

    Scheler, Marina; Wenzel, Joerg; Tüting, Thomas; Takikawa, Osamu; Bieber, Thomas; von Bubnoff, Dagmar

    2007-01-01

    Recent studies have provided evidence that a type I interferon (IFN)-driven immune response might play an important role in the pathogenesis of lichen planus (LP), an inflammatory disorder of the skin of unclear etiology. Plasmacytoid dendritic cells in affected skin from LP have been proposed to produce IFN-α/β locally, which leads to the expression of IFN-inducible chemokines such as IP10/CXCL10 in the epidermis. This chemokine recruits chemokine receptor CXCR3-expressing T-lymphocytes into the skin via CXCR3/IP10 interactions. Indoleamine 2,3-dioxygenase (IDO), which degrades tryptophan and suppresses T-cell proliferation, is induced by IFNs and other inflammatory cytokines. We show that type I IFN-mediated skin disorders, such as LP, strongly express IDO in lesional skin. This expression closely correlates to the expression of the highly specific type I IFN marker MxA. We further demonstrate that the IDO+ cells in LP are large myeloid CD11c+S100+CD68− dendritic cells. Accordingly, CD11c+ antigen-presenting cells significantly up-regulate IDO gene expression and intracellular IDO protein expression after stimulation with IFN-α in vitro. These findings reveal that both proinflammatory and counterregulatory mechanisms are operative in cutaneous lesions of LP. We propose that the balance of these mechanisms may be involved in the pathogenesis of this disorder. PMID:18055547

  19. Exploring the mechanism of tryptophan 2,3-dioxygenase

    Science.gov (United States)

    Thackray, Sarah J.; Mowat, Christopher G.; Chapman, Stephen K.

    2008-01-01

    The haem proteins TDO (tryptophan 2,3-dioxygenase) and IDO (indoleamine 2,3-dioxygenase) are specific and powerful oxidation catalysts that insert one molecule of dioxygen into L-tryptophan in the first and rate-limiting step in the kynurenine pathway. Recent crystallographic and biochemical analyses of TDO and IDO have greatly aided our understanding of the mechanisms employed by these enzymes in the binding and activation of dioxygen and tryptophan. In the present paper, we briefly discuss the function, structure and possible catalytic mechanism of these enzymes. PMID:19021508

  20. Modulating Tumor Immunology by Inhibiting Indoleamine 2,3-Dioxygenase (IDO): Recent Developments and First Clinical Experiences.

    Science.gov (United States)

    Davar, Diwakar; Bahary, Nathan

    2018-04-01

    Indoleamine 2,3-dioxygenase (IDO) and tryptophan 2,3-dioxygenase (TDO) catalyze the first rate-limiting step in the oxidative metabolism of compounds containing indole rings, including the transformation of the essential amino acid L-tryptophan to N-formyl-L-kynurenine. Through direct and indirect means, IDO exerts both tolerogenic and pro-inflammatory effects and has a profound immunoregulatory role in the tumor microenvironment. Although the role of IDO in mediating peripheral acquired immunologic tolerance has been known for some time, its role in tumorigenesis and the subversion of anti-tumor immunity have only recently been appreciated. Small-molecule inhibitors of IDO1 and TDO are being evaluated as single agents and in combination with immune checkpoint blockade in a host of advanced cancers. In this review, we delineate the tolerogenic and pro-inflammatory effects of IDO as it relates to immune escape and discuss current clinical progress in this area.

  1. Enzyme Specificity of 2-Nitrotoluene 2,3-Dioxygenase from Pseudomonas sp. Strain JS42 Is Determined by the C-Terminal Region of the α Subunit of the Oxygenase Component

    Science.gov (United States)

    Parales, Juanito V.; Parales, Rebecca E.; Resnick, Sol M.; Gibson, David T.

    1998-01-01

    Biotransformations with recombinant Escherichia coli expressing the genes encoding 2-nitrotoluene 2,3-dioxygenase (2NTDO) from Pseudomonas sp. strain JS42 demonstrated that 2NTDO catalyzes the dihydroxylation and/or monohydroxylation of a wide range of aromatic compounds. Extremely high nucleotide and deduced amino acid sequence identity exists between the components from 2NTDO and the corresponding components from 2,4-dinitrotoluene dioxygenase (2,4-DNTDO) from Burkholderia sp. strain DNT (formerly Pseudomonas sp. strain DNT). However, comparisons of the substrates oxidized by these dioxygenases show that they differ in substrate specificity, regiospecificity, and the enantiomeric composition of their oxidation products. Hybrid dioxygenases were constructed with the genes encoding 2NTDO and 2,4-DNTDO. Biotransformation experiments with these hybrid dioxygenases showed that the C-terminal region of the large subunit of the oxygenase component (ISPα) was responsible for the enzyme specificity differences observed between 2NTDO and 2,4-DNTDO. The small subunit of the terminal oxygenase component (ISPβ) was shown to play no role in determining the specificities of these dioxygenases. PMID:9495758

  2. Isolation of recombinant cysteine dioxygenase protein from Trichophyton mentagrophytes

    Czech Academy of Sciences Publication Activity Database

    Kašperová, A.; Kunert, J.; Horynová, M.; Weigl, E.; Sebela, M.; Lenobel, René; Raška, M.

    2011-01-01

    Roč. 54, č. 5 (2011), E456-E462 ISSN 0933-7407 R&D Projects: GA ČR GA301/08/1649 Institutional research plan: CEZ:AV0Z50380511 Keywords : Cysteine dioxygenase * dermatophytes * recombinant protein * keratinolytic fungi * cDNA Subject RIV: CE - Biochemistry Impact factor: 2.247, year: 2011

  3. Detection of meta - and ortho -cleavage dioxygenases in bacterial ...

    African Journals Online (AJOL)

    In contrast, isolates S-5, Sea-8, W-6, W-15 and Pla-1 showed activity with the enzyme catalyzing the second step in the phenol degradation meta-cleavage pathway, catechol-2,3-dioxygenase. On the basis of our previous and present analysis, the investigated isolates are considered to have a good potential for application ...

  4. Characterization and Functional Identification of a Novel Plant 4,5-Extradiol Dioxygenase Involved in Betalain Pigment Biosynthesis in Portulaca grandiflora

    Science.gov (United States)

    Christinet, Laurent; Burdet, Frédéric X.; Zaiko, Maïa; Hinz, Ursula; Zrÿd, Jean-Pierre

    2004-01-01

    Betalains are pigments that replace anthocyanins in the majority of families of the plant order Caryophyllales. Betalamic acid is the common chromophore of betalains. The key enzyme of the betalain biosynthetic pathway is an extradiol dioxygenase that opens the cyclic ring of dihydroxy-phenylalanine (DOPA) between carbons 4 and 5, thus producing an unstable seco-DOPA that rearranges nonenzymatically to betalamic acid. A gene for a 4,5-DOPA-dioxygenase has already been isolated from the fungus Amanita muscaria, but no homolog was ever found in plants. To identify the plant gene, we constructed subtractive libraries between different colored phenotypes of isogenic lines of Portulaca grandiflora (Portulacaceae) and between different stages of flower bud formation. Using in silico analysis of differentially expressed cDNAs, we identified a candidate showing strong homology at the level of translated protein with the LigB domain present in several bacterial extradiol 4,5-dioxygenases. The gene was expressed only in colored flower petals. The function of this gene in the betalain biosynthetic pathway was confirmed by biolistic genetic complementation in white petals of P. grandiflora genotypes lacking the gene for color formation. This gene named DODA is the first characterized member of a novel family of plant dioxygenases phylogenetically distinct from Amanita sp. DOPA-dioxygenase. Homologs of DODA are present not only in betalain-producing plants but also, albeit with some changes near the catalytic site, in other angiosperms and in the bryophyte Physcomitrella patens. These homologs are part of a novel conserved plant gene family probably involved in aromatic compound metabolism. PMID:14730069

  5. Structures of the human poly (ADP-ribose glycohydrolase catalytic domain confirm catalytic mechanism and explain inhibition by ADP-HPD derivatives.

    Directory of Open Access Journals (Sweden)

    Julie A Tucker

    Full Text Available Poly(ADP-ribose glycohydrolase (PARG is the only enzyme known to catalyse hydrolysis of the O-glycosidic linkages of ADP-ribose polymers, thereby reversing the effects of poly(ADP-ribose polymerases. PARG deficiency leads to cell death whilst PARG depletion causes sensitisation to certain DNA damaging agents, implicating PARG as a potential therapeutic target in several disease areas. Efforts to develop small molecule inhibitors of PARG activity have until recently been hampered by a lack of structural information on PARG. We have used a combination of bio-informatic and experimental approaches to engineer a crystallisable, catalytically active fragment of human PARG (hPARG. Here, we present high-resolution structures of the catalytic domain of hPARG in unliganded form and in complex with three inhibitors: ADP-ribose (ADPR, adenosine 5'-diphosphate (hydroxymethylpyrrolidinediol (ADP-HPD and 8-n-octyl-amino-ADP-HPD. Our structures confirm conservation of overall fold amongst mammalian PARG glycohydrolase domains, whilst revealing additional flexible regions in the catalytic site. These new structures rationalise a body of published mutational data and the reported structure-activity relationship for ADP-HPD based PARG inhibitors. In addition, we have developed and used biochemical, isothermal titration calorimetry and surface plasmon resonance assays to characterise the binding of inhibitors to our PARG protein, thus providing a starting point for the design of new inhibitors.

  6. Auto-triggerable HPD sensors fully readout on Ethernet, applications for high energy physics and medical imaging

    International Nuclear Information System (INIS)

    Katsanevas, S.; Largeron, G.; Marteau, J.; Moret, G.

    2002-01-01

    The OPERA project is dedicated to neutrino oscillation search in the CNGS neutrino beam from CERN to Gran Sasso. The experiment is designed to characterize the interaction of ν τ resulted from the ν μ → ν τ oscillation. The main element of the detector is a brick consisting of the emulsion sheets interleaved with lead plates. These bricks are assembled in walls of about 7 m side. A total of 72 walls is foreseen for OPERA experiment with a total of fiducial mass of 2 k tons. When a neutrino interaction occurs the tracks of the charged particles are recorded in the emulsions with a high accuracy and the topology of the event is fully reconstructed with an automatic scanning of the emulsions. The role of the target tracker in OPERA is to locate the brick where the primary neutrino interaction occurs to provide triggers and to make a coarser reconstruction of the events. It consists of 2 planes of scintillator strips located after a brick wall.. The scintillation photons are collected by WLS fibers and read by a multi-pixel photodetector. The results obtained with 61 pixels HPDs readout by auto-triggerable front-end electronics of the VA-TA series. A new kind of acquisition system based on Ethernet abler to read the front-end electronics and deliver the data directly to the Ethernet network is described. The Ethernet DAQ system is based on a ORCA (Opera Readout Card) module which includes all the features to control the front-end and the time stamping of the trigger of the events. The front-end electronics and the HPD characteristics are described in Sections 2 and 3 while the PMT which validates the acquisition chain is presented in Section 4. Medical applications and the results obtained with the acquisition system used as micro pet and for characterized photodetectors in High Energy experiment are also presented

  7. Molecular detection and diversity of novel diterpenoid dioxygenase DitA1 genes from proteobacterial strains and soil samples.

    Science.gov (United States)

    Witzig, Robert; Aly, Hamdy A H; Strömpl, Carsten; Wray, Victor; Junca, Howard; Pieper, Dietmar H

    2007-05-01

    Resin acids are tricyclic diterpenoids naturally synthesized by trees that are released from wood during pulping processes. Using a newly designed primer set, genes similar to that encoding the DitA1 catalytic alpha-subunit of the diterpenoid dioxygenase, a key enzyme in abietane resin acid degradation by Pseudomonas abietaniphila BKME-9, could be amplified from different Pseudomonas strains, whereas ditA1 gene sequence types representing distinct branches in the evolutionary tree were amplified from Burkholderia and Cupriavidus isolates. All isolates harbouring a ditA1-homologue were capable of growth on dehydroabietic acid as the sole source of carbon and energy and reverse transcription polymerase chain reaction analysis in three strains confirmed that ditA1 was expressed constitutively or in response to DhA, demonstrating its involvement in DhA-degradation. Evolutionary analyses indicate that gyrB (as a phylogenetic marker) and ditA1 genes have coevolved under purifying selection from their ancestral variants present in the most recent common ancestor of the genera Pseudomonas, Cupriavidus and Burkholderia. A polymerase chain reaction-single-strand conformation poylmorphism fingerprinting method was established to monitor the diversity of ditA1 genes in environmental samples. The molecular fingerprints indicated the presence ofa broad, previously unrecognized diversity of diterpenoid dioxygenase genes in soils, and suggest that other bacterial phyla may also harbour the genetic potential for DhA-degradation.

  8. Lowering the Barriers to Using Data: Enabling Desktop-based HPD Science through Virtual Environments and Web Data Services

    Science.gov (United States)

    Druken, K. A.; Trenham, C. E.; Steer, A.; Evans, B. J. K.; Richards, C. J.; Smillie, J.; Allen, C.; Pringle, S.; Wang, J.; Wyborn, L. A.

    2016-12-01

    The Australian National Computational Infrastructure (NCI) provides access to petascale data in climate, weather, Earth observations, and genomics, and terascale data in astronomy, geophysics, ecology and land use, as well as social sciences. The data is centralized in a closely integrated High Performance Computing (HPC), High Performance Data (HPD) and cloud facility. Despite this, there remain significant barriers for many users to find and access the data: simply hosting a large volume of data is not helpful if researchers are unable to find, access, and use the data for their particular need. Use cases demonstrate we need to support a diverse range of users who are increasingly crossing traditional research discipline boundaries. To support their varying experience, access needs and research workflows, NCI has implemented an integrated data platform providing a range of services that enable users to interact with our data holdings. These services include: - A GeoNetwork catalog built on standardized Data Management Plans to search collection metadata, and find relevant datasets; - Web data services to download or remotely access data via OPeNDAP, WMS, WCS and other protocols; - Virtual Desktop Infrastructure (VDI) built on a highly integrated on-site cloud with access to both the HPC peak machine and research data collections. The VDI is a fully featured environment allowing visualization, code development and analysis to take place in an interactive desktop environment; and - A Learning Management System (LMS) containing User Guides, Use Case examples and Jupyter Notebooks structured into courses, so that users can self-teach how to use these facilities with examples from our system across a range of disciplines. We will briefly present these components, and discuss how we engage with data custodians and consumers to develop standardized data structures and services that support the range of needs. We will also highlight some key developments that have

  9. INDOLEAMINE 2,3-DIOXYGENASE (IDO AND IMMUNE TOLERANCE

    Directory of Open Access Journals (Sweden)

    Coma-del-Corral MJ

    2013-09-01

    Full Text Available SUMMARY: Indoleamine 2,3-dioxygenase (IDO is an intracellular and extrahepatic enzyme predominantly found in many cells, especially macrophages. Tryptophan degradation generates kynurenine, and this pathway of tryptophan metabolism is an effective mechanism for modulating the immune response. The IDO facilitates immune tolerance and is one of the main actors involved in the inhibition of cell proliferation, including activated T cells. IDO induces production of reactive oxygen species (ROS and nitric oxide (NO radicals. Several pathways involved in the regulation of immune response are regulated by redox mechanisms. Reactive oxygen and nitrogen species (ROS-RNS and other redox active molecules play key roles in immunity.

  10. Separation of chlorogenic acid from honeysuckle crude extracts by macroporous resins.

    Science.gov (United States)

    Zhang, Bin; Yang, Ruiyuan; Zhao, Yan; Liu, Chun-Zhao

    2008-05-15

    Chlorogenic acid, one of the most bioactive compounds rich in the Chinese medicinal herb honeysuckle, is a natural antioxidant and serves as anti-inflammatory, anti-tumor, anti-mutagenic and anti-carcinogenic agent. An efficient preparative separation process of chlorogenic acid from honeysuckle crude extracts has been developed in the present study. HPD-850 resin offers the best adsorption capacity, and adsorption and desorption ratios for chlorogenic acid among the nine macroporous resins tested, and its adsorption rate at 25 degrees C fit best to the Langmuir isotherm. The adsorption capacity of HPD-850 resin was found to depend strongly on the pH value of the initial adsorption solution. The dynamic adsorption and desorption experiments have been carried out on a HPD-850 resin packed column to optimize the separation process of chlorogenic acid from honeysuckle crude extracts. After one run treatment with HPD-850 resin, the chlorogenic acid content in the final product was increased 4.46-fold from 11.2% to 50.0%, with a recovery yield of 87.9%. The preparative separation of chlorogenic acid can be easily and efficiently achieved via adsorption and desorption on HPD-850 resin, and the method developed will provide a potential approach for large-scale separation and purification of chlorogenic acid for its wide pharmaceutical use.

  11. Analysis of phylogenetic and functional diverge in plant nine-cis epoxycarotenoid dioxygenase gene family.

    Science.gov (United States)

    Priya, R; Siva, Ramamoorthy

    2015-07-01

    During different environmental stress conditions, plant growth is regulated by the hormone abscisic acid (an apocarotenoid). In the biosynthesis of abscisic acid, the oxidative cleavage of cis-epoxycarotenoid catalyzed by 9-cis-epoxycarotenoid dioxygenase (NCED) is the crucial step. The NCED genes were isolated in numerous plant species and those genes were phylogenetically investigated to understand the evolution of NCED genes in various plant lineages comprising lycophyte, gymnosperm, dicot and monocot. A total of 93 genes were obtained from 48 plant species to statistically estimate their sequence conservation and functional divergence. Selaginella moellendorffii appeared to be evolutionarily distinct from those of the angiosperms, insisting the substantial influence of natural selection pressure on NCED genes. Further, using exon-intron structure analysis, the gene structures of NCED were found to be conserved across some species. In addition, the substitution rate ratio of non-synonymous (Ka) versus synonymous (Ks) mutations using the Bayesian inference approach, depicted the critical amino acid residues for functional divergence. A significant functional divergence was found between some subgroups through the co-efficient of type-I functional divergence. Our results suggest that the evolution of NCED genes occurred by duplication, diversification and exon intron loss events. The site-specific profile and functional diverge analysis revealed NCED genes might facilitate the tissue-specific functional divergence in NCED sub-families, that could combat different environmental stress conditions aiding plant survival.

  12. Substrate Recognition and Catalysis by the Cofactor-Independent Dioxygenase DpgC+

    Energy Technology Data Exchange (ETDEWEB)

    Fielding,E.; Widboom, P.; Bruner, S.

    2007-01-01

    The enzyme DpgC belongs to a small class of oxygenases not dependent on accessory cofactors for activity. DpgC is in the biosynthetic pathway for the nonproteinogenic amino acid 3, 5-dihydroxyphenylglycine in actinomycetes bacteria responsible for the production of the vancomycin/teicoplanin family of antibiotic natural products. The X-ray structure of DpgC confirmed the absence of cofactors and defined a novel hydrophobic dioxygen binding pocket adjacent to a bound substrate analogue. In this paper, the role specific amino acids play in substrate recognition and catalysis is examined through biochemical and structural characterization of site-specific enzyme mutations and alternate substrates. The results establish the importance of three amino acids, Arg254, Glu299, and Glu189, in the chemistry of DpgC. Arg254 and Glu189 join to form a specific contact with one of the phenolic hydroxyls of the substrate, and this interaction plays a key role in both substrate recognition and catalysis. The X-ray crystal structure of Arg254Lys was determined to address the role this residue plays in the chemistry. In addition, characterization of alternate substrate analogues demonstrates the presence and position of phenol groups are necessary for both enzyme recognition and downstream oxidation chemistry. Overall, this work defines the mechanism of substrate recognition and specificity by the cofactor-independent dioxygenase DpgC.

  13. Tryptophan 2,3-dioxygenase and indoleamine 2,3-dioxygenase 1 make separate, tissue-specific contributions to basal and inflammation-induced kynurenine pathway metabolism in mice.

    Science.gov (United States)

    Larkin, Paul B; Sathyasaikumar, Korrapati V; Notarangelo, Francesca M; Funakoshi, Hiroshi; Nakamura, Toshikazu; Schwarcz, Robert; Muchowski, Paul J

    2016-11-01

    In mammals, the majority of the essential amino acid tryptophan is degraded via the kynurenine pathway (KP). Several KP metabolites play distinct physiological roles, often linked to immune system functions, and may also be causally involved in human diseases including neurodegenerative disorders, schizophrenia and cancer. Pharmacological manipulation of the KP has therefore become an active area of drug development. To target the pathway effectively, it is important to understand how specific KP enzymes control levels of the bioactive metabolites in vivo. Here, we conducted a comprehensive biochemical characterization of mice with a targeted deletion of either tryptophan 2,3-dioxygenase (TDO) or indoleamine 2,3-dioxygenase (IDO), the two initial rate-limiting enzymes of the KP. These enzymes catalyze the same reaction, but differ in biochemical characteristics and expression patterns. We measured KP metabolite levels and enzyme activities and expression in several tissues in basal and immune-stimulated conditions. Although our study revealed several unexpected downstream effects on KP metabolism in both knockout mice, the results were essentially consistent with TDO-mediated control of basal KP metabolism and a role of IDO in phenomena involving stimulation of the immune system. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. EXPRESSION AND POST-TRANSLATIONAL MODIFICATION OF HUMAN 4-HYDROXY-PHENYLPYRUVATE DIOXYGENASE

    DEFF Research Database (Denmark)

    Aarenstrup, Lene; Falch, Anne-Marie; Jakobsen, Kirsten K.

    2002-01-01

    12q24¿qter. In the present study high-resolution chromosome mapping localized the HPD gene to 12q24.31. DNase I footprinting, revealed that four regions of the HPD promoter were protected by rat liver nuclear proteins. Computer-assisted analyses suggested that these elements might bind Sp1/AP2, HNF4......, HNF3/CREB, and C/EBP, respectively. In transient transfection experiments, the proximal 271 bp of the promoter conferred basal transcriptional activation in human Chang cells. Sequences in intron 1 were able to enhance the activity of this basal promoter. Finally, vaccinia virus-based expression...

  15. Crystallization and preliminary crystallographic analysis of maganese(II)-dependent 2,3-dihydroxybiphenyl 1,2-dioxygenase from Bacillus sp. JF8

    International Nuclear Information System (INIS)

    Senda, Miki; Hatta, Takashi; Kimbara, Kazuhide; Senda, Toshiya

    2010-01-01

    A thermostable manganese(II)-dependent 2,3-dihydroxybiphenyl-1,2-dioxygenase derived from Bacillus sp. JF8 was crystallized in two forms using the sitting-drop vapour-diffusion method. Both crystals diffracted to approximately 1.3 Å resolution. A thermostable manganese(II)-dependent 2,3-dihydroxybiphenyl-1,2-dioxygenase derived from Bacillus sp. JF8 was crystallized. The initial screening for crystallization was performed by the sitting-drop vapour-diffusion method using a crystallization robot, resulting in the growth of two crystal forms. The first crystal belonged to space group P1, with unit-cell parameters a = 62.7, b = 71.4, c = 93.6 Å, α = 71.2, β = 81.0, γ = 64.0°, and diffracted to 1.3 Å resolution. The second crystal belonged to space group I222, with unit-cell parameters a = 74.2, b = 90.8, c = 104.3 Å, and diffracted to 1.3 Å resolution. Molecular-replacement trials using homoprotocatechuate 2,3-dioxygenase from Arthrobacter globiformis (28% amino-acid sequence identity) as a search model provided a satisfactory solution for both crystal forms

  16. Characterization of DitA3, the [Fe3S4] ferredoxin of an aromatic ring-hydroxylating dioxygenase from a diterpenoid-degrading microorganism.

    Science.gov (United States)

    Couture, Manon M-J; Martin, Vincent J J; Mohn, William W; Eltis, Lindsay D

    2006-09-01

    DitA3, a small soluble ferredoxin, is a component of a ring-hydroxylating dioxygenase involved in the microbial degradation of the diterpenoid, dehydroabietic acid. The anaerobic purification of a heterologously expressed his-tagged DitA3 yielded 20 mg of apparently homogeneous recombinant protein, rcDitA3, per liter of cell culture. Each mole of purified rcDitA3 contained 2.9 equivalents of iron and 4.2 equivalents of sulfur, indicating the presence of a single [Fe(3)S(4)] cluster. This conclusion was corroborated by UV-Visible absorption (epsilon(412)=13.4 mM(-1) cm(-1)) and EPR (g(x,y)=2.00 and g(z)=2.02) spectroscopies. The reduction potential of rcDitA3, determined using a highly oriented parallel graphite (HOPG) electrode, was -177.0+/-0.5 mV vs. the standard hydrogen electrode (SHE) (20 mM MOPS, 80 mM KCl, pH 7.0, 22 degrees C). This potential is similar to those of small, soluble Rieske-type ferredoxin components of aromatic-ring dihydroxylating dioxygenases. In contrast to these Rieske-type ferredoxins, DitA3 appears to exist as a dimer in solution. The dimeric ferredoxin may be more stable or may increase the catalytic efficiency of the dioxygenase by delivering the two reducing equivalents required for turnover of the oxygenase.

  17. INHIBITION OF INDOLEAMINE 2,3-DIOXYGENASE DOES NOT IMPEDE ORAL TOLERANCE

    Science.gov (United States)

    Rationale: Indoleamine 2,3-dioxygenase (IDO), a tryptophan catabolizing enzyme, regulates immune tolerance through inhibition of T-cell proliferation. Pharmacologic inhibition of IDO, which causes fetal rejection and increased tumor resistance in mice, may prove useful in cancer...

  18. Crystallization and preliminary crystallographic studies of human indoleamine 2,3-dioxygenase

    Energy Technology Data Exchange (ETDEWEB)

    Oda, Shun-ichiro [Biometal Science Laboratory, RIKEN SPring-8 Center, Harima Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); Department of Life Science, Graduate School of Science, University of Hyogo, Kamigori Ako, Hyogo 678-1297 (Japan); Sugimoto, Hiroshi, E-mail: sugimoto@spring8.or.jp [Biometal Science Laboratory, RIKEN SPring-8 Center, Harima Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); Yoshida, Tadashi [Department of Biochemistry, Yamagata University School of Medicine, Yamagata 990-9585 (Japan); Shiro, Yoshitsugu [Biometal Science Laboratory, RIKEN SPring-8 Center, Harima Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); Department of Life Science, Graduate School of Science, University of Hyogo, Kamigori Ako, Hyogo 678-1297 (Japan)

    2006-03-01

    Human indoleamine 2,3-dioxygenase, a haem-containing dioxygenase, was crystallized. The crystal diffracted to 2.3 Å resolution. Indoleamine 2,3-dioxygenase (IDO) is a haem-containing dioxygenase that catalyzes the oxidative cleavage of the pyrrole ring of indoleamines by the insertion of molecular oxygen. This reaction is the first and the rate-limiting step in the kynurenine pathway, the major Trp catabolic pathway in mammals. Recombinant human IDO was crystallized by the vapour-diffusion technique. The addition of 4-phenylimidazole as a haem ligand was essential for crystallization. The crystals belong to space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 86.1, b = 98.0, c = 131.0 Å. Diffraction data were collected to 2.3 Å resolution.

  19. Effect of different drying techniques on bioactive components, fatty acid composition, and volatile profile of robusta coffee beans.

    Science.gov (United States)

    Dong, Wenjiang; Hu, Rongsuo; Chu, Zhong; Zhao, Jianping; Tan, Lehe

    2017-11-01

    This study investigated the effect of different drying techniques, namely, room-temperature drying (RTD), solar drying (SD), heat-pump drying (HPD), hot-air drying (HAD), and freeze drying (FD), on bioactive components, fatty acid composition, and the volatile compound profile of robusta coffee beans. The data showed that FD was an effective method to preserve fat, organic acids, and monounsaturated fatty acids. In contrast, HAD was ideal for retaining polyunsaturated fatty acids and amino acids. Sixty-two volatile compounds were identified in the differently dried coffee beans, representing 90% of the volatile compounds. HPD of the coffee beans produced the largest number of volatiles, whereas FD resulted in the highest volatile content. A principal component analysis demonstrated a close relationship between the HPD, SD, and RTD methods whereas the FD and HAD methods were significantly different. Overall, the results provide a basis for potential application to other similar thermal sensitive materials. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. The aryloxyalkanoate dioxygenase-12 (AAD-12) protein is not acutely toxic in mice.

    Science.gov (United States)

    Papineni, Sabitha; Golden, Rachel M; Thomas, Johnson

    2017-12-01

    Typically, when a protein is orally toxic, it acts via acute mechanisms, especially at high doses. Therefore, an acute oral toxicity study is considered appropriate for evaluating the safety of transgenic proteins. Soybean plants (events DAS-68416-4 and DAS-444Ø6-6) have been genetically modified to express the aryloxyalkanoate dioxygenase-12 (AAD-12) protein. The AAD-12 protein provides tolerance to the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). This paper summarizes the study designs of two acute oral toxicity studies evaluating the AAD-12 protein and reports the results of these studies. No mortalities or adverse effects were observed in mice when AAD-12 was tested up to a limit dose of 5000 mg/kg body weight. Based on the results of these studies, it can be concluded that AAD-12 protein, as expressed in genetically modified DAS-68416-4 and DAS-444Ø6-6 soybeans, lacks acute toxicity via the oral route. Copyright © 2017. Published by Elsevier Ltd.

  1. Identification and expression pattern of a new carotenoid cleavage dioxygenase gene member from Bixa orellana

    Science.gov (United States)

    Rodríguez-Ávila, N. L.; Narváez-Zapata, J. A.; Ramírez-Benítez, J. E.; Aguilar-Espinosa, M. L.; Rivera-Madrid, R.

    2011-01-01

    Carotenoid cleavage dioxygenases (CCDs) are a class of enzymes involved in the biosynthesis of a broad diversity of secondary metabolites known as apocarotenoids. In plants, CCDs are part of a genetic family with members which cleave specific double bonds of carotenoid molecules. CCDs are involved in the production of diverse and important metabolites such as vitamin A and abscisic acid (ABA). Bixa orellana L. is the main source of the natural pigment annatto or bixin, an apocarotenoid accumulated in large quantities in its seeds. Bixin biosynthesis has been studied and the involvement of a CCD has been confirmed in vitro. However, the CCD genes involved in the biosynthesis of the wide variety of apocarotenoids found in this plant have not been well documented. In this study, a new CCD1 gene member (BoCCD1) was identified and its expression was charaterized in different plant tissues of B. orellana plantlets and adult plants. The BoCCD1 sequence showed high homology with plant CCD1s involved mainly in the cleavage of carotenoids in several sites to generate multiple apocarotenoid products. Here, the expression profiles of the BoCCD1 gene were analysed and discussed in relation to total carotenoids and other important apocarotenoids such as bixin. PMID:21813796

  2. Spectroscopic and computational studies of reversible O2binding by a cobalt complex of relevance to cysteine dioxygenase.

    Science.gov (United States)

    Fischer, Anne A; Lindeman, Sergey V; Fiedler, Adam T

    2017-10-10

    The substitution of non-native metal ions into metalloenzyme active sites is a common strategy for gaining insights into enzymatic structure and function. For some nonheme iron dioxygenases, replacement of the Fe(ii) center with a redox-active, divalent transition metal (e.g., Mn, Co, Ni, Cu) gives rise to an enzyme with equal or greater activity than the wild-type enzyme. In this manuscript, we apply this metal-substitution approach to synthetic models of the enzyme cysteine dioxygenase (CDO). CDO is a nonheme iron dioxygenase that initiates the catabolism of l-cysteine by converting this amino acid to the corresponding sulfinic acid. Two mononuclear Co(ii) complexes (3 and 4) have been prepared with the general formula [Co 2+ (Tp R2 )(CysOEt)] (R = Ph (3) or Me (4); Tp R2 = hydrotris(pyrazol-1-yl)borate substituted with R-groups at the 3- and 5-positions, and CysOEt is the anion of l-cysteine ethyl ester). These Co(ii) complexes mimic the active-site structure of substrate-bound CDO and are analogous to functional iron-based CDO models previously reported in the literature. Characterization with X-ray crystallography and/or 1 H NMR spectroscopy revealed that 3 and 4 possess five-coordinate structures featuring facially-coordinating Tp R2 and S,N-bidentate CysOEt ligands. The electronic properties of these high-spin (S = 3/2) complexes were interrogated with UV-visible absorption and X-band electron paramagnetic resonance (EPR) spectroscopies. The air-stable nature of complex 3 replicates the inactivity of cobalt-substituted CDO. In contrast, complex 4 reversibly binds O 2 at reduced temperatures to yield an orange chromophore (4-O 2 ). Spectroscopic (EPR, resonance Raman) and computational (density functional theory, DFT) analyses indicate that 4-O 2 is a S = 1/2 species featuring a low-spin Co(iii) center bound to an end-on (η 1 ) superoxo ligand. DFT calculations were used to evaluate the energetics of key steps in the reaction mechanism. Collectively, these

  3. Cloning and Expression of the Benzoate Dioxygenase Genes from Rhodococcus sp. Strain 19070

    Science.gov (United States)

    Haddad, Sandra; Eby, D. Matthew; Neidle, Ellen L.

    2001-01-01

    The bopXYZ genes from the gram-positive bacterium Rhodococcus sp. strain 19070 encode a broad-substrate-specific benzoate dioxygenase. Expression of the BopXY terminal oxygenase enabled Escherichia coli to convert benzoate or anthranilate (2-aminobenzoate) to a nonaromatic cis-diol or catechol, respectively. This expression system also rapidly transformed m-toluate (3-methylbenzoate) to an unidentified product. In contrast, 2-chlorobenzoate was not a good substrate. The BopXYZ dioxygenase was homologous to the chromosomally encoded benzoate dioxygenase (BenABC) and the plasmid-encoded toluate dioxygenase (XylXYZ) of gram-negative acinetobacters and pseudomonads. Pulsed-field gel electrophoresis failed to identify any plasmid in Rhodococcus sp. strain 19070. Catechol 1,2- and 2,3-dioxygenase activity indicated that strain 19070 possesses both meta- and ortho-cleavage degradative pathways, which are associated in pseudomonads with the xyl and ben genes, respectively. Open reading frames downstream of bopXYZ, designated bopL and bopK, resembled genes encoding cis-diol dehydrogenases and benzoate transporters, respectively. The bop genes were in the same order as the chromosomal ben genes of P. putida PRS2000. The deduced sequences of BopXY were 50 to 60% identical to the corresponding proteins of benzoate and toluate dioxygenases. The reductase components of these latter dioxygenases, BenC and XylZ, are 201 residues shorter than the deduced BopZ sequence. As predicted from the sequence, expression of BopZ in E. coli yielded an approximately 60-kDa protein whose presence corresponded to increased cytochrome c reductase activity. While the N-terminal region of BopZ was approximately 50% identical in sequence to the entire BenC or XylZ reductases, the C terminus was unlike other known protein sequences. PMID:11375157

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

    NARCIS (Netherlands)

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

    Pseudomonas putida GJ31 contains an unusual catechol 2,3-dioxygenase that converts 3-chlorocatechol and 3-methylcatechol, which enables the organism to use both chloroaromatics and methylaromatics for growth, A 3.1-kb region of genomic DNA of strain GJ31 containing the gene for this chlorocatechol

  5. Kinetic analysis of human homogentisate 1,2-dioxygenase.

    Science.gov (United States)

    Amaya, Alphonso A; Brzezinski, Kotanee T; Farrington, Natasha; Moran, Graham R

    2004-01-01

    Homogentisate 1,2-dioxygenase (HGD) is a mononuclear Fe(II)-dependent oxygenase that catalyzes the third step in the pathway for the catabolism of tyrosine, the conversion of homogentisate (HG) to maleylacetoacetate (MAA). We have heterologously expressed and purified native human HGD in the apo form. Steady-state analysis varying the concentration of both HG and molecular oxygen shows that the purified enzyme has a turnover number of 16 s(-1). Our data suggest that HG binds to the apo-enzyme and that the apo-HGD.HG complex does not bind Fe(II) and dissociates slowly at approximately 0.028 s(-1). The rate constant for the dissociation of Fe(II) from the holo-enzyme as measured under anaerobic conditions is 0.00004 s(-1) and indicates that this process is not relevant in steady-state turnover. The addition of HG and molecular oxygen to the holo-enzyme is formally random as the holo-enzyme reduces molecular oxygen at a rate of 1.35x10(3) M(-1) s(-1) at 4 degrees C. The term ordered with respect to the addition of substrates is most descriptive as the rate of reduction of molecular oxygen must increase in the presence of HG to sustain the observed turnover number.

  6. Engineering Non-Heme Mono- and Dioxygenases for Biocatalysis

    Directory of Open Access Journals (Sweden)

    Adi Dror

    2012-09-01

    Full Text Available Oxygenases are ubiquitous enzymes that catalyze the introduction of one or two oxygen atoms to unreactive chemical compounds. They require reduction equivalents from NADH or NADPH and comprise metal ions, metal ion complexes, or coenzymes in their active site. Thus, for industrial purposes, oxygenases are most commonly employed using whole cell catalysis, to alleviate the need for co-factor regeneration. Biotechnological applications include bioremediation, chiral synthesis, biosensors, fine chemicals, biofuels, pharmaceuticals, food ingredients and polymers. Controlling activity and selectivity of oxygenases is therefore of great importance and of growing interest to the scientific community. This review focuses on protein engineering of non-heme monooxygenases and dioxygenases for generating improved or novel functionalities. Rational mutagenesis based on x-ray structures and sequence alignment, as well as random methods such as directed evolution, have been utilized. It is concluded that knowledge-based protein engineering accompanied with targeted libraries, is most efficient for the design and tuning of biocatalysts towards novel substrates and enhanced catalytic activity while minimizing the screening efforts.

  7. Antitumour agents as inhibitors of tryptophan 2,3-dioxygenase

    Energy Technology Data Exchange (ETDEWEB)

    Pantouris, Georgios; Mowat, Christopher G., E-mail: C.G.Mowat@ed.ac.uk

    2014-01-03

    Highlights: •∼2800 National Cancer Institute USA compounds have been screened as potential inhibitors of TDO and/or IDO. •Seven compounds with anti-tumour properties have been identified as potent inhibitors. •NSC 36398 (taxifolin, dihydroquercetin) is selective for TDO with a K{sub i} of 16 M. •This may help further our understanding of the role of TDO in cancer. -- Abstract: The involvement of tryptophan 2,3-dioxygenase (TDO) in cancer biology has recently been described, with the enzyme playing an immunomodulatory role, suppressing antitumour immune responses and promoting tumour cell survival and proliferation. This finding reinforces the need for specific inhibitors of TDO that may potentially be developed for therapeutic use. In this work we have screened ∼2800 compounds from the library of the National Cancer Institute USA and identified seven potent inhibitors of TDO with inhibition constants in the nanomolar or low micromolar range. All seven have antitumour properties, killing various cancer cell lines. For comparison, the inhibition potencies of these compounds were tested against IDO and their inhibition constants are reported. Interestingly, this work reveals that NSC 36398 (dihydroquercetin, taxifolin), with an in vitro inhibition constant of ∼16 μM, is the first TDO-selective inhibitor reported.

  8. Crystal Structure of Mammalian Cysteine dioxygenase: A Novel Mononuclear Iron Center for Cysteine Thiol Oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Simmons,C.; Liu, Q.; Huang, Q.; Hao, Q.; Begley, T.; Karplus, P.; Stipanuk, M.

    2006-01-01

    Cysteine dioxygenase is a mononuclear iron-dependent enzyme responsible for the oxidation of cysteine with molecular oxygen to form cysteinesulfinate. This reaction commits cysteine to either catabolism to sulfate and pyruvate or to the taurine biosynthetic pathway. Cysteine dioxygenase is a member of the cupin superfamily of proteins. The crystal structure of recombinant rat cysteine dioxygenase has been determined to 1.5 Angstroms resolution, and these results confirm the canonical cupin {beta}-sandwich fold and the rare cysteinyl-tyrosine intramolecular crosslink (between Cys93 and Tyr157) seen in the recently reported murine cysteine dioxygenase structure. In contrast to the catalytically inactive mononuclear Ni(II) metallocenter present in the murine structure, crystallization of a catalytically competent preparation of rat cysteine dioxygenase revealed a novel tetrahedrally coordinated mononuclear iron center involving three histidines (His86, His88, and His140) and a water molecule. Attempts to acquire a structure with bound ligand using either co-crystallization or soaks with cysteine revealed the formation of a mixed disulfide involving Cys164 near the active site, which may explain previously observed substrate inhibition. This work provides a framework for understanding the molecular mechanisms involved in thiol dioxygenation and sets the stage for exploring the chemistry of both the novel mononuclear iron center and the catalytic role of the cysteinyl-tyrosine linkage.

  9. Degradation of chloroanilines by toluene dioxygenase from Pseudomonas putida T57.

    Science.gov (United States)

    Nitisakulkan, Tisana; Oku, Shota; Kudo, Daizo; Nakashimada, Yutaka; Tajima, Takahisa; Vangnai, Alisa S; Kato, Junichi

    2014-03-01

    In this study, we investigated the ability of Pseudomonas putida toluene dioxygenase to oxidize chloroanilines. Toluene-induced P. putida T57 cells degraded 4-chloroaniline (4CA) more rapidly than toluene-non-induced cells, suggesting that toluene dioxygenase pathway was involved in 4CA degradation. Escherichia coli harboring P. putida T57 genes encoding toluene dioxygenase complex (todC1C2BA) showed 4CA degradation activity, demonstrating that toluene dioxygenase oxidizes 4CA. Thin-layer chromatography (TLC) and mass spectrometry (MS) analyses identified 4-chlorocatechol and 2-amino-5-chlorophenol as reaction products, suggesting that toluene dioxygenase catalyzes both 1,2- and 2,3-dioxygenation of 4CA. A plasmid containing the entire tod operon (todC1C2BADE) was introduced to P. putida T57 to enhance its ability to degrade 4CA. Resulting P. putida T57 (pHK-C1C2BADE) showed 250-fold higher 4CA degradation activity than P. putida T57 parental strain. P. putida T57 (pHK-C1C2BADE) degraded 2-chloroaniline (2CA), 3-chloroaniline (3CA), and 3,4-dichloroaniline (34DCA) as well as 4CA, but not 3,5-dichloroaniline (35DCA). The order of the degradation rate was: 4CA > 3CA > 2CA > 34DCA. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  10. The salicylate 1,2-dioxygenase as a model for a conventional gentisate 1,2-dioxygenase: crystal structures of the G106A mutant and its adducts with gentisate and salicylate.

    Science.gov (United States)

    Ferraroni, Marta; Matera, Irene; Bürger, Sibylle; Reichert, Sabrina; Steimer, Lenz; Scozzafava, Andrea; Stolz, Andreas; Briganti, Fabrizio

    2013-04-01

    The salicylate 1,2-dioxygenase (SDO) from the bacterium Pseudaminobacter salicylatoxidans BN12 is a versatile gentisate 1,2-dioxygenase (GDO) that converts both gentisate (2,5-dihydroxybenzoate) and various monohydroxylated substrates. Several variants of this enzyme were rationally designed based on the previously determined enzyme structure and sequence differences between the SDO and the 'conventional' GDO from Corynebacterium glutamicum. This was undertaken in order to define the structural elements that give the SDO its unique ability to dioxygenolytically cleave (substituted) salicylates. SDO variants M103L, G106A, G111A, R113G, S147R and F159Y were constructed and it was found that G106A oxidized only gentisate; 1-hydroxy-2-naphthoate and salicylate were not converted. This indicated that this enzyme variant behaves like previously known 'conventional' GDOs. Crystals of the G106A SDO variant and its complexes with salicylate and gentisate were obtained under anaerobic conditions, and the structures were solved and analyzed. The amino acid residue Gly106 is located inside the SDO active site cavity but does not directly interact with the substrates. Crystal structures of G106A SDO complexes with gentisate and salicylate showed a different binding mode for salicylate when compared with the wild-type enzyme. Thus, salicylate coordinated in the G106A variant with the catalytically active Fe(II) ion in an unusual and unproductive manner because of the inability of salicylate to displace a hydrogen bond that was formed between Trp104 and Asp174 in the G106A variant. It is proposed that this type of unproductive substrate binding might generally limit the substrate spectrum of 'conventional' GDOs. Structural data are available in the Protein Data Bank databases under the accession numbers 3NST, 3NWA, 3NVC. © 2013 The Authors Journal compilation © 2013 FEBS.

  11. In situ, real-time catabolic gene expression: Extraction and characterization of naphthalene dioxygenase mRNA transcripts from groundwater

    International Nuclear Information System (INIS)

    Wilson, M.S.; Bakermans, C.; Madsen, E.L.

    1999-01-01

    The authors developed procedures for isolating and characterizing in situ-transcribed mRNA from groundwater microorganisms catabolizing naphthalene at a coal tar waste-contaminated site. Groundwater was pumped through 0.22-microm-pore-size filters, which were then frozen to dry ice-ethanol. RNA was extracted from the frozen filters by boiling sodium dodecyl sulfate lysis and acidic phenol-chloroform extraction. Transcript characterization was performed with a series of PCR primers designed to amplify nahAc homologs. Several primer pairs were found to amplify nahAc homologs representing the entire diversity of the naphthalene-degrading genes. The environmental RNA extract was reverse transcribed, and the resultant mixture of cDNAs was amplified by PCR. A digoxigenin-labeled probe mixture was produced by PCR amplification of groundwater cDNA. This probe mixture hybridized under stringent conditions with the corresponding PCR products from naphthalene-degrading bacteria carrying a variety of nahAc homologs, indicating that diverse dioxygenase transcripts had been retrieved from groundwater. Diluted and undiluted cDNA preparations were independently amplified, and 28 of the resulting PCR products were cloned and sequenced. Sequence comparisons revealed two major groups related to the dioxygenase genes ndoB and dntAc, previously cloned from Pseudomonas putida NCIB 9816-4 and Burkholderia sp. strain DNT, respectively. A distinctive subgroup of sequences was found only in experiments performed with the undiluted cDNA preparation. To the authors' knowledge, these results are the first to directly document in situ transcription of genes encoding naphthalene catabolism at a contaminated site by indigenous microorganisms. The retrieved sequences represent greater diversity than has been detected at the study site by culture-based approaches

  12. Cloning and functional characterization of carotenoid cleavage dioxygenase 4 genes.

    Science.gov (United States)

    Huang, Fong-Chin; Molnár, Péter; Schwab, Wilfried

    2009-01-01

    Although a number of plant carotenoid cleavage dioxygenase (CCD) genes have been functionally characterized in different plant species, little is known about the biochemical role and enzymatic activities of members of the subclass 4 (CCD4). To gain insight into their biological function, CCD4 genes were isolated from apple (Malus x domestica, MdCCD4), chrysanthemum (Chrysanthemum x morifolium, CmCCD4a), rose (Rosa x damascena, RdCCD4), and osmanthus (Osmanthus fragrans, OfCCD4), and were expressed, together with AtCCD4, in Escherichia coli. In vivo assays showed that CmCCD4a and MdCCD4 cleaved beta-carotene well to yield beta-ionone, while OfCCD4, RdCCD4, and AtCCD4 were almost inactive towards this substrate. No cleavage products were found for any of the five CCD4 genes when they were co-expressed in E. coli strains that accumulated cis-zeta-carotene and lycopene. In vitro assays, however, demonstrated the breakdown of 8'-apo-beta-caroten-8'-al by AtCCD4 and RdCCD4 to beta-ionone, while this apocarotenal was almost not degraded by OfCCD4, CmCCD4a, and MdCCD4. Sequence analysis of genomic clones of CCD4 genes revealed that RdCCD4, like AtCCD4, contains no intron, while MdCCD, OfCCD4, and CmCCD4a contain introns. These results indicate that plants produce at least two different forms of CCD4 proteins. Although CCD4 enzymes cleave their substrates at the same position (9,10 and 9',10'), they might have different biochemical functions as they accept different (apo)-carotenoid substrates, show various expression patterns, and are genomically differently organized.

  13. INDOLEAMINE 2,3-DIOXYGENASE INDUCES EXPRESSION OF A NOVEL TRYPTOPHAN TRANSPORTER IN MOUSE AND HUMAN TUMOR CELLS1

    Science.gov (United States)

    Silk, Jonathan D.; Lakhal, Samira; Laynes, Robert; Vallius, Laura; Karydis, Ioannis; Marcea, Cornelius; Boyd, C. A. Richard; Cerundolo, Vincenzo

    2011-01-01

    Indoleamine 2,3 dioxygenase (IDO) is the rate-limiting enzyme in the kynurenine pathway, catabolizing tryptophan to kynurenine. Tryptophan depletion by IDO expressing tumors is a common mechanism of immune evasion inducing regulatory T cells and inhibiting effector T cells. As mammalian cells cannot synthesize tryptophan, it remains unclear how IDO positive tumor cells overcome the detrimental effects of local tryptophan depletion. We demonstrate that IDO positive tumor cells express a novel amino acid transporter, which accounts for approximately 50% of the tryptophan uptake. The induced transporter is biochemically distinguished from the constitutively expressed tryptophan transporter System L by increased resistance to inhibitors of System L, resistance to inhibition by high concentrations of most amino acids tested, and high substrate specificity for tryptophan. Under conditions of low extracellular tryptophan, expression of this novel transporter significantly increases tryptophan entry into IDO positive tumors relative to tryptophan uptake through the low affinity System L alone, and further decreases tryptophan levels in the microenvironment. Targeting this additional tryptophan transporter could be a way of pharmacological inhibition of IDO mediated tumor escape. These findings highlight the ability of IDO-expressing tumor cells to thrive in a tryptophan depleted microenvironment by expressing a novel, highly tryptophan-specific transporter, which is resistant to inhibition by most other amino acids. The additional transporter allows tumor cells to strike the ideal balance between supply of tryptophan essential for their own proliferation and survival, and depleting the extracellular milieu of tryptophan to inhibit T cell proliferation. PMID:21742973

  14. Activation of ethylene-responsive p-hydroxyphenylpyruvate dioxygenase leads to increased tocopherol levels during ripening in mango

    Science.gov (United States)

    Singh, Rajesh K.; Ali, Sharique A.; Nath, Pravendra; Sane, Vidhu A.

    2011-01-01

    Mango is characterized by high tocopherol and carotenoid content during ripening. From a cDNA screen of differentially expressing genes during mango ripening, a full-length p-hydroxyphenylpyruvate dioxygenase (MiHPPD) gene homologue was isolated that encodes a key enzyme in the biosynthesis of tocopherols. The gene encoded a 432-amino-acid protein. Transcript analysis during different stages of ripening revealed that the gene is ripening related and rapidly induced by ethylene. The increase in MiHPPD transcript accumulation was followed by an increase in tocopherol levels during ripening. The ripening-related increase in MiHPPD expression was also seen in response to abscisic acid and to alesser extent to indole-3-acetic acid. The expression of MiHPPD was not restricted to fruits but was also seen in other tissues such as leaves particularly during senescence. The strong ethylene induction of MiHPPD was also seen in young leaves indicating that ethylene induction of MiHPPD is tissue independent. Promoter analysis of MiHPPD gene in tomato discs and leaves of stable transgenic lines of Arabidopsis showed that the cis elements for ripening-related, ethylene-responsive, and senescence-related expression resided within the 1590 nt region upstream of the ATG codon. Functionality of the gene was demonstrated by the ability of the expressed protein in bacteria to convert p-hydroxyphenylpyruvate to homogentisate. These results provide the first evidence for HPPD expression during ripening of a climacteric fruit. PMID:21430290

  15. Expression of tryptophan 2,3-dioxygenase and production of kynurenine pathway metabolites in triple transgenic mice and human Alzheimer's disease brain.

    Directory of Open Access Journals (Sweden)

    Wei Wu

    Full Text Available To assess the role of the kynurenine pathway in the pathology of Alzheimer's disease (AD, the expression and localization of key components of the kynurenine pathway including the key regulatory enzyme tryptophan 2,3 dioxygenase (TDO, and the metabolites tryptophan, kynurenine, kynurenic acid, quinolinic acid and picolinic acid were assessed in different brain regions of triple transgenic AD mice. The expression and cell distribution of TDO and quinolinic acid, and their co-localization with neurofibrillary tangles and senile β amyloid deposition were also determined in hippocampal sections from human AD brains. The expression of TDO mRNA was significantly increased in the cerebellum of AD mouse brain. Immunohistochemistry demonstrated that the density of TDO immuno-positive cells was significantly higher in the AD mice. The production of the excitotoxin quinolinic acid strongly increased in the hippocampus in a progressive and age-dependent manner in AD mice. Significantly higher TDO and indoleamine 2,3 dioxygenase 1 immunoreactivity was observed in the hippocampus of AD patients. Furthermore, TDO co-localizes with quinolinic acid, neurofibrillary tangles-tau and amyloid deposits in the hippocampus of AD. These results show that the kynurenine pathway is over-activated in AD mice. This is the first report demonstrating that TDO is highly expressed in the brains of AD mice and in AD patients, suggesting that TDO-mediated activation of the kynurenine pathway could be involved in neurofibrillary tangles formation and associated with senile plaque. Our study adds to the evidence that the kynurenine pathway may play important roles in the neurodegenerative processes of AD.

  16. Structural Investigations of the Ferredoxin and Terminal Oxygenase Components of the biphenyl 2,3-dioxygenase from Sphingobium yanoikuyae B1

    Energy Technology Data Exchange (ETDEWEB)

    Ferraro,D.; Brown, E.; Yu, C.; Parales, R.; Gibson, D.; Ramaswamy, S.

    2007-01-01

    The initial step involved in oxidative hydroxylation of monoaromatic and polyaromatic compounds by the microorganism Sphingobium yanoikuyae strain B1 (B1), previously known as Sphingomonas yanoikuyae strain B1 and Beijerinckia sp. strain B1, is performed by a set of multiple terminal Rieske non-heme iron oxygenases. These enzymes share a single electron donor system consisting of a reductase and a ferredoxin (BPDO-F{sub B1}). One of the terminal Rieske oxygenases, biphenyl 2,3-dioxygenase (BPDO-O{sub B1}), is responsible for B1's ability to dihydroxylate large aromatic compounds, such as chrysene and benzo(a)pyrene. Results: In this study, crystal structures of BPDO-O{sub B1} in both native and biphenyl bound forms are described. Sequence and structural comparisons to other Rieske oxygenases show this enzyme to be most similar, with 43.5 % sequence identity, to naphthalene dioxygenase from Pseudomonas sp. strain NCIB 9816-4. While structurally similar to naphthalene 1,2-dioxygenase, the active site entrance is significantly larger than the entrance for naphthalene 1,2-dioxygenase. Differences in active site residues also allow the binding of large aromatic substrates. There are no major structural changes observed upon binding of the substrate. BPDO-F{sub B1} has large sequence identity to other bacterial Rieske ferredoxins whose structures are known and demonstrates a high structural homology; however, differences in side chain composition and conformation around the Rieske cluster binding site are noted. Conclusion: This is the first structure of a Rieske oxygenase that oxidizes substrates with five aromatic rings to be reported. This ability to catalyze the oxidation of larger substrates is a result of both a larger entrance to the active site as well as the ability of the active site to accommodate larger substrates. While the biphenyl ferredoxin is structurally similar to other Rieske ferredoxins, there are distinct changes in the amino acids near the

  17. An iron-oxygen intermediate formed during the catalytic cycle of cysteine dioxygenase.

    Science.gov (United States)

    Tchesnokov, E P; Faponle, A S; Davies, C G; Quesne, M G; Turner, R; Fellner, M; Souness, R J; Wilbanks, S M; de Visser, S P; Jameson, G N L

    2016-07-07

    Cysteine dioxygenase is a key enzyme in the breakdown of cysteine, but its mechanism remains controversial. A combination of spectroscopic and computational studies provides the first evidence of a short-lived intermediate in the catalytic cycle. The intermediate decays within 20 ms and has absorption maxima at 500 and 640 nm.

  18. Benzoate degradation by Rhodococcus opacus 1CP after dormancy: Characterization of dioxygenases involved in the process.

    Science.gov (United States)

    Solyanikova, Inna P; Emelyanova, Elena V; Borzova, Oksana V; Golovleva, Ludmila A

    2016-01-01

    The process of benzoate degradation by strain Rhodococcus opacus 1CP after a five-year dormancy was investigated and its peculiarities were revealed. The strain was shown to be capable of growth on benzoate at a concentration of up to 10 g L(-1). The substrate specificity of benzoate dioxygenase (BDO) during the culture growth on a medium with a low (200-250 mg L(-1)) and high (4 g L(-1)) concentration of benzoate was assessed. BDO of R. opacus 1CP was shown to be an extremely narrow specificity enzyme. Out of 31 substituted benzoates, only with one, 3-chlorobenzoate, its activity was higher than 9% of that of benzoate. Two dioxygenases, catechol 1,2-dioxygenase (Cat 1,2-DO) and protocatechuate 3,4-dioxygenase (PCA 3,4-DO), were identified in a cell-free extract, purified and characterized. The substrate specificity of Cat 1,2-DO isolated from cells of strain 1CP after the dormancy was found to differ significantly from that of Cat 1,2-DO isolated earlier from cells of this strain grown on benzoate. By its substrate specificity, the described Cat 1,2-DO was close to the Cat 1,2-DO from strain 1CP grown on 4-methylbenzoate. Neither activity nor inhibition by protocatechuate was observed during the reaction of Cat 1,2-DO with catechol, and catechol had no inhibitory effect on the reaction of PCA 3,4-DO with protocatechuate.

  19. A biological pathway linking inflammation and depression: activation of indoleamine 2,3-dioxygenase

    Directory of Open Access Journals (Sweden)

    Christmas DM

    2011-07-01

    Full Text Available David M Christmas, JP Potokar, Simon JC DaviesAcademic Unit of Psychiatry, School of Social and Community Medicine, University of Bristol, Bristol, UK A presentation relating to this manuscript was made by Dr David Christmas at the 9th International Meeting on Clinical Pharmacology in Psychiatry (9th IMCPP in Copenhagen, Denmark in September 2010Abstract: This article highlights the evidence linking depression to increased inflammatory drive and explores putative mechanisms for the association by reviewing both preclinical and clinical literature. The enzyme indoleamine 2,3-dioxygenase is induced by proinflammatory cytokines and may form a link between immune functioning and altered neurotransmission, which results in depression. Increased indoleamine 2,3-dioxygenase activity may cause both tryptophan depletion and increased neurotoxic metabolites of the kynurenine pathway, two alterations which have been hypothesized to cause depression. The tryptophan-kynurenine pathway is comprehensively described with a focus on the evidence linking metabolite alterations to depression. The use of immune-activated groups at high risk of depression have been used to explore these hypotheses; we focus on the studies involving chronic hepatitis C patients receiving interferon-alpha, an immune activating cytokine. Findings from this work have led to novel strategies for the future development of antidepressants including inhibition of indoleamine 2,3-dioxygenase, moderating the cytokines which activate it, or addressing other targets in the kynurenine pathway.Keywords: depression, inflammation, indoleamine 2,3-dioxygenase, kynurenine, serotonin, tryptophan

  20. The NCI High Performance Computing (HPC) and High Performance Data (HPD) Platform to Support the Analysis of Petascale Environmental Data Collections

    Science.gov (United States)

    Evans, B. J. K.; Pugh, T.; Wyborn, L. A.; Porter, D.; Allen, C.; Smillie, J.; Antony, J.; Trenham, C.; Evans, B. J.; Beckett, D.; Erwin, T.; King, E.; Hodge, J.; Woodcock, R.; Fraser, R.; Lescinsky, D. T.

    2014-12-01

    The National Computational Infrastructure (NCI) has co-located a priority set of national data assets within a HPC research platform. This powerful in-situ computational platform has been created to help serve and analyse the massive amounts of data across the spectrum of environmental collections - in particular the climate, observational data and geoscientific domains. This paper examines the infrastructure, innovation and opportunity for this significant research platform. NCI currently manages nationally significant data collections (10+ PB) categorised as 1) earth system sciences, climate and weather model data assets and products, 2) earth and marine observations and products, 3) geosciences, 4) terrestrial ecosystem, 5) water management and hydrology, and 6) astronomy, social science and biosciences. The data is largely sourced from the NCI partners (who include the custodians of many of the national scientific records), major research communities, and collaborating overseas organisations. By co-locating these large valuable data assets, new opportunities have arisen by harmonising the data collections, making a powerful transdisciplinary research platformThe data is accessible within an integrated HPC-HPD environment - a 1.2 PFlop supercomputer (Raijin), a HPC class 3000 core OpenStack cloud system and several highly connected large scale and high-bandwidth Lustre filesystems. New scientific software, cloud-scale techniques, server-side visualisation and data services have been harnessed and integrated into the platform, so that analysis is performed seamlessly across the traditional boundaries of the underlying data domains. Characterisation of the techniques along with performance profiling ensures scalability of each software component, all of which can either be enhanced or replaced through future improvements. A Development-to-Operations (DevOps) framework has also been implemented to manage the scale of the software complexity alone. This ensures that

  1. Spontaneous release of fluoride during the dioxygenolytic cleavage of 5-fluorosalicylate by the salicylate 1,2-dioxygenase from Pseudaminobacter salicylatoxidans BN12.

    Science.gov (United States)

    Eppinger, Erik; Bürger, Sibylle; Stolz, Andreas

    2016-01-01

    The alpha-Proteobacterium Pseudaminobacter salicylatoxidans BN12 forms a peculiar gentisate 1,2-dioxygenase (SDO) that oxidatively cleaves gentisate (2,5-dihydroxybenzoate) and additionally 1-hydroxy-2-naphthoate, salicylate and various amino-, chloro-, fluoro-, hydroxy- and methylsalicylates. In the present study, the conversion of 5-fluorosalicylate by this enzyme was analysed using various analytical techniques. Spectrophotometric assays showed that the conversion of 5-fluorosalicylate by the purified enzyme resulted in the formation of a new unstable intermediate showing an absorbance maximum at λmax = 292 nm. The analysis of the enzymatic reaction by HPLC showed that two main products with absorbance maxima at λmax = 292-296 nm were formed from 5-fluorosalicylate. The same two products (although in different relative proportions) were also formed when the SDO transformed 5-chlorosalicylate or when a purified 5-nitrosalicylate 1,2-dioxygenase from Bradyrhizobium sp. JS329 oxidized 5-nitrosalicylate. A whole cell system with recombinant Escherichia coli cells overexpressing the SDO activity was established in order to produce larger amounts of the reaction products. The reaction products were subsequently identified by (1)H-NMR and mass spectrometry as stereoisomers of 2-oxo-3-(5-oxofuran-2-ylidine)propanoic acid. The release of fluoride in the course of the dioxygenolytic cleavage reaction was confirmed by ion-chromatography and (19)F-NMR. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Preparation, crystallization and X-ray diffraction analysis to 1.5 Å resolution of rat cysteine dioxygenase, a mononuclear iron enzyme responsible for cysteine thiol oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Simmons, Chad R. [Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853-8001 (United States); Hao, Quan [MacCHESS at the Cornell High Energy Synchrotron Source, Cornell University, Ithaca, NY 14853-8001 (United States); Stipanuk, Martha H., E-mail: mhs6@cornell.edu [Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853-8001 (United States)

    2005-11-01

    Recombinant rat cysteine dioxygenase (CDO) has been expressed, purified and crystallized and X-ray diffraction data have been collected to 1.5 Å resolution. Cysteine dioxygenase (CDO; EC 1.13.11.20) is an ∼23 kDa non-heme iron metalloenzyme that is responsible for the oxidation of cysteine by O{sub 2}, yielding cysteinesulfinate. CDO catalyzes the first step in the conversion of cysteine to taurine, as well as the first step in the catabolism of cysteine to pyruvate plus sulfate. Recombinant rat CDO was heterologously expressed, purified and crystallized. The protein was expressed as a fusion protein bearing a polyhistidine tag to facilitate purification, a thioredoxin tag to improve solubility and a factor Xa cleavage site to permit removal of the entire N-terminus, leaving only the 200 amino acids inherent to the native protein. A multi-step purification scheme was used to achieve >95% purity of CDO. The optimal CDO crystals diffracted to 1.5 Å resolution and belonged to space group P4{sub 3}2{sub 1}2 or P4{sub 1}2{sub 1}2, with unit-cell parameters a = b = 57.55, c = 123.06 Å, α = β = γ = 90°. CDO shows little homology to any other proteins; therefore, the structure of the enzyme will be determined by ab initio phasing using a selenomethionyl derivative.

  3. Putative mitochondrial α-ketoglutarate-dependent dioxygenase Fmp12 controls utilization of proline as an energy source in Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Ikuhisa Nishida

    2016-09-01

    Full Text Available The amino acid proline functions as a nitrogen source and as a stress protectant in the yeast Saccharomyces cerevisiae. However, utilization of proline as a carbon source in S. cerevisiae cells has not been studied yet. In the process of study on the physiological roles of the found-in-mitochondrial-proteome (FMP genes in proline metabolism, we found that Δfmp12 cells could grow better than wild-type cells on agar plate medium containing proline as the sole nitrogen and carbon sources. In contrast, overexpression of FMP12 negatively affected cell growth under the same condition. The Fmp12 protein was localized in the mitochondria and was constitutively expressed. Deletion of the genes that encode mitochondrial enzymes, such as proline dehydrogenase (PUT1, Δ1-pyrroline-5-carboxylate dehydrogenase (PUT2, alanine transaminase (ALT1, and α-ketoglutarate dehydrogenase subunit (KGD1, abolished the enhanced cell growth in Δfmp12. These results provided the first evidence that proline can be utilized as a carbon source via the mitochondrial proline metabolic pathway and the subsequent tricarboxylic acid (TCA cycle in S. cerevisiae. The function of Fmp12, which has a similarity with α-ketoglutarate-dependent dioxygenases of the yeast Candida species and human, might inhibit cell growth by skipping the ATP production step of the TCA cycle.

  4. Diversity of 16S rRNA and dioxygenase genes detected in coal-tar-contaminated site undergoing active bioremediation.

    Science.gov (United States)

    Kumar, M; Khanna, S

    2010-04-01

    In order to develop effective bioremediation strategies for polyaromatic hydrocarbons (PAHs) degradation, the composition and metabolic potential of microbial communities need to be better understood, especially in highly PAH contaminated sites in which little information on the cultivation-independent communities is available. Coal-tar-contaminated soil was collected, which consisted of 122.5 mg g(-1) total extractable PAH compounds. Biodegradation studies with this soil indicated the presence of microbial community that is capable of degrading the model PAH compounds viz naphthalene, phenanthrene and pyrene at 50 ppm each. PCR clone libraries were established from the DNA of the coal-tar-contaminated soil, targeting the 16S rRNA to characterize (i) the microbial communities, (ii) partial gene fragment encoding the Rieske iron sulfur center (alpha-subunit) common to all PAH dioxygenase enzymes and (iii) beta-subunit of dioxygenase. Phylotypes related to Proteobacteria (Alpha-, Epsilon- and Gammaproteobacteria), Acidobacteria, Actinobacteria, Firmicutes, Gemmatimonadetes and Deinococci were detected in 16S rRNA derived clone libraries. Many of the gene fragment sequences of alpha-subunit and beta-subunit of dioxygenase obtained from the respective clone libraries fell into clades that are distinct from the reference dioxygenase gene sequences. Presence of consensus sequence of the Rieske type [2Fe-2S] cluster binding site suggested that these gene fragments encode for alpha-subunit of dioxygenase gene. Sequencing of the cloned libraries representing alpha-subunit gene fragments (Rf1) and beta-subunit of dioxygenase showed the presence of hitherto unidentified dioxygenase in coal-tar-contaminated soil. The combination of the Rieske primers and bacterial community profiling represents a powerful tool for both assessing bioremediation potential and the exploration of novel dioxygenase genes in a contaminated environment.

  5. Purification and Characterization of Carbazole 1,9a-Dioxygenase, a Three-Component Dioxygenase System of Pseudomonas resinovorans Strain CA10

    OpenAIRE

    Nam, Jeong-Won; Nojiri, Hideaki; Noguchi, Haruko; Uchimura, Hiromasa; Yoshida, Takako; Habe, Hiroshi; Yamane, Hisakazu; Omori, Toshio

    2002-01-01

    The carbazole 1,9a-dioxygenase (CARDO) system of Pseudomonas resinovorans strain CA10 consists of terminal oxygenase (CarAa), ferredoxin (CarAc), and ferredoxin reductase (CarAd). Each component of CARDO was expressed in Escherichia coli strain BL21(DE3) as a native form (CarAa) or a His-tagged form (CarAc and CarAd) and was purified to apparent homogeneity. CarAa was found to be trimeric and to have one Rieske type [2Fe-2S] cluster and one mononuclear iron center in each monomer. Both His-ta...

  6. Characterization of Metal Binding in the Active Sites of acireductone dioxygenase Isoforms from Klebsiella ATCC 8724

    Energy Technology Data Exchange (ETDEWEB)

    S Chai; T Ju; M Dang; R Goldsmith; M Maroney; T Pochapsky

    2011-12-31

    The two acireductone dioxygenase (ARD) isozymes from the methionine salvage pathway of Klebsiella ATCC 8724 present an unusual case in which two enzymes with different structures and distinct activities toward their common substrates (1,2-dihydroxy-3-oxo-5-(methylthio)pent-1-ene and dioxygen) are derived from the same polypeptide chain. Structural and functional differences between the two isozymes are determined by the type of M{sup 2+} metal ion bound in the active site. The Ni{sup 2+}-bound NiARD catalyzes an off-pathway shunt from the methionine salvage pathway leading to the production of formate, methylthiopropionate, and carbon monoxide, while the Fe{sup 2+}-bound FeARD catalyzes the on-pathway formation of methionine precursor 2-keto-4-methylthiobutyrate and formate. Four potential protein-based metal ligands were identified by sequence homology and structural considerations. Based on the results of site-directed mutagenesis experiments, X-ray absorption spectroscopy (XAS), and isothermal calorimetry measurements, it is concluded that the same four residues, His96, His98, Glu102 and His140, provide the protein-based ligands for the metal in both the Ni- and Fe-containing forms of the enzyme, and subtle differences in the local backbone conformations trigger the observed structural and functional differences between the FeARD and NiARD isozymes. Furthermore, both forms of the enzyme bind their respective metals with pseudo-octahedral geometry, and both may lose a histidine ligand upon binding of substrate under anaerobic conditions. However, mutations at two conserved nonligand acidic residues, Glu95 and Glu100, result in low metal contents for the mutant proteins as isolated, suggesting that some of the conserved charged residues may aid in transfer of metal from in vivo sources or prevent the loss of metal to stronger chelators. The Glu100 mutant reconstitutes readily but has low activity. Mutation of Asp101 results in an active enzyme that incorporates

  7. Novel carotenoid cleavage dioxygenase catalyzes the first dedicated step in saffron crocin biosynthesis

    KAUST Repository

    Frusciante, Sarah

    2014-08-05

    Crocus sativus stigmas are the source of the saffron spice and accumulate the apocarotenoids crocetin, crocins, picrocrocin, and safranal, responsible for its color, taste, and aroma. Through deep transcriptome sequencing, we identified a novel dioxygenase, carotenoid cleavage dioxygenase 2 (CCD2), expressed early during stigma development and closely related to, but distinct from, the CCD1 dioxygenase family. CCD2 is the only identified member of a novel CCD clade, presents the structural features of a bona fide CCD, and is able to cleave zeaxanthin, the presumed precursor of saffron apocarotenoids, both in Escherichia coli and in maize endosperm. The cleavage products, identified through high-resolution mass spectrometry and comigration with authentic standards, are crocetin dialdehyde and crocetin, respectively. In vitro assays show that CCD2 cleaves sequentially the 7,8 and 7′,8′ double bonds adjacent to a 3-OH-β-ionone ring and that the conversion of zeaxanthin to crocetin dialdehyde proceeds via the C30 intermediate 3-OH-β-apo-8′-carotenal. In contrast, zeaxanthin cleavage dioxygenase (ZCD), an enzyme previously claimed to mediate crocetin formation, did not cleave zeaxanthin or 3-OH-β-apo-8′-carotenal in the test systems used. Sequence comparison and structure prediction suggest that ZCD is an N-truncated CCD4 form, lacking one blade of the β-propeller structure conserved in all CCDs. These results constitute strong evidence that CCD2 catalyzes the first dedicated step in crocin biosynthesis. Similar to CCD1, CCD2 has a cytoplasmic localization, suggesting that it may cleave carotenoids localized in the chromoplast outer envelope.

  8. An isoelectronic NO dioxygenase reaction using a nonheme iron(III)-peroxo complex and nitrosonium ion†

    Science.gov (United States)

    Yokoyama, Atsutoshi; Han, Jung Eun; Karlin, Kenneth D.; Nam, Wonwoo

    2014-01-01

    Reaction of a nonheme iron(III)-peroxo complex, [FeIII(14-TMC)(O2)]+, with NO+, a transformation which is essentially isoelectronic with that for nitric oxide dioxygenases [Fe(III)(O2•−) + NO], affords an iron(IV)-oxo complex, [FeIV(14-TMC)(O)]2+, and nitrogen dioxide (NO2), followed by conversion to an iron(III)-nitrato complex, [FeIII(14-TMC)(NO3)(F)]+. PMID:24394960

  9. New Insight into the Cleavage Reaction of Nostoc sp. Strain PCC 7120 Carotenoid Cleavage Dioxygenase in Natural and Nonnatural Carotenoids

    Science.gov (United States)

    Heo, Jinsol; Kim, Se Hyeuk

    2013-01-01

    Carotenoid cleavage dioxygenases (CCDs) are enzymes that catalyze the oxidative cleavage of carotenoids at a specific double bond to generate apocarotenoids. In this study, we investigated the activity and substrate preferences of NSC3, a CCD of Nostoc sp. strain PCC 7120, in vivo and in vitro using natural and nonnatural carotenoid structures. NSC3 cleaved β-apo-8′-carotenal at 3 positions, C-13C-14, C-15C-15′, and C-13′C-14′, revealing a unique cleavage pattern. NSC3 cleaves the natural structure of carotenoids 4,4′-diaponeurosporene, 4,4′-diaponeurosporen-4′-al, 4,4′-diaponeurosporen-4′-oic acid, 4,4′-diapotorulene, and 4,4′-diapotorulen-4′-al to generate novel cleavage products (apo-14′-diaponeurosporenal, apo-13′-diaponeurosporenal, apo-10′-diaponeurosporenal, apo-14′-diapotorulenal, and apo-10′-diapotorulenal, respectively). The study of carotenoids with natural or nonnatural structures produced by using synthetic modules could provide information valuable for understanding the cleavage reactions or substrate preferences of other CCDs in vivo and in vitro. PMID:23524669

  10. Characterization of dioxygenases and biosurfactants produced by crude oil degrading soil bacteria

    Directory of Open Access Journals (Sweden)

    Santhakumar Muthukamalam

    Full Text Available ABSTRACT Role of microbes in bioremediation of oil spills has become inevitable owing to their eco friendly nature. This study focused on the isolation and characterization of bacterial strains with superior oil degrading potential from crude-oil contaminated soil. Three such bacterial strains were selected and subsequently identified by 16S rRNA gene sequence analysis as Corynebacterium aurimucosum, Acinetobacter baumannii and Microbacterium hydrocarbonoxydans respectively. The specific activity of catechol 1,2 dioxygenase (C12O and catechol 2,3 dioxygenase (C23O was determined in these three strains wherein the activity of C12O was more than that of C23O. Among the three strains, Microbacterium hydrocarbonoxydans exhibited superior crude oil degrading ability as evidenced by its superior growth rate in crude oil enriched medium and enhanced activity of dioxygenases. Also degradation of total petroleum hydrocarbon (TPH in crude oil was higher with Microbacterium hydrocarbonoxydans. The three strains also produced biosurfactants of glycolipid nature as indicated d by biochemical, FTIR and GCMS analysis. These findings emphasize that such bacterial strains with superior oil degrading capacity may find their potential application in bioremediation of oil spills and conservation of marine and soil ecosystem.

  11. Prokaryotic Homologs of the Eukaryotic 3-Hydroxyanthranilate 3,4-Dioxygenase and 2-Amino-3-Carboxymuconate-6-Semialdehyde Decarboxylase in the 2-Nitrobenzoate Degradation Pathway of Pseudomonas fluorescens Strain KU-7†

    OpenAIRE

    Muraki, Takamichi; Taki, Masami; Hasegawa, Yoshie; Iwaki, Hiroaki; Lau, Peter C. K.

    2003-01-01

    The 2-nitrobenzoic acid degradation pathway of Pseudomonas fluorescens strain KU-7 proceeds via a novel 3-hydroxyanthranilate intermediate. In this study, we cloned and sequenced a 19-kb DNA locus of strain KU-7 that encompasses the 3-hydroxyanthranilate meta-cleavage pathway genes. The gene cluster, designated nbaEXHJIGFCDR, is organized tightly and in the same direction. The nbaC and nbaD gene products were found to be novel homologs of the eukaryotic 3-hydroxyanthranilate 3,4-dioxygenase a...

  12. Molecular cloning and characterization of cDNAs encoding carotenoid cleavage dioxygenase in bitter melon (Momordica charantia).

    Science.gov (United States)

    Tuan, Pham Anh; Park, Sang Un

    2013-01-01

    Carotenoid cleavage dioxygenases (CCDs) are a family of enzymes that catalyze the oxidative cleavage of carotenoids at various chain positions to form a broad spectrum of apocarotenoids, including aromatic substances, pigments and phytohormones. Using the rapid amplification of cDNA ends (RACE) PCR method, we isolated three cDNA-encoding CCDs (McCCD1, McCCD4, and McNCED) from Momordica charantia. Amino acid sequence alignments showed that they share high sequence identity with other orthologous genes. Quantitative real-time RT PCR (reverse transcriptase PCR) analysis revealed that the expression of McCCD1 and McCCD4 was highest in flowers, and lowest in roots and old leaves (O-leaves). During fruit maturation, the two genes displayed differential expression, with McCCD1 peaking at mid-stage maturation while McCCD4 showed the lowest expression at that stage. The mRNA expression level of McNCED, a key enzyme involved in abscisic acid (ABA) biosynthesis, was high during fruit maturation and further increased at the beginning of seed germination. When first-leaf stage plants of M. charantia were exposed to dehydration stress, McNCED mRNA expression was induced primarily in the leaves and, to a lesser extend, in roots and stems. McNCED expression was also induced by high temperature and salinity, while treatment with exogenous ABA led to a decrease. These results should be helpful in determining the substrates and cleavage sites catalyzed by CCD genes in M. charantia, and also in defining the roles of CCDs in growth and development, and in the plant's response to environmental stress. Copyright © 2012 Elsevier GmbH. All rights reserved.

  13. Role of 9-lipoxygenase and α-dioxygenase oxylipin pathways as modulators of local and systemic defense.

    Science.gov (United States)

    Vicente, Jorge; Cascón, Tomás; Vicedo, Begonya; García-Agustín, Pilar; Hamberg, Mats; Castresana, Carmen

    2012-07-01

    Plant 9-lipoxygenases (9-LOX) and α-dioxygenases (α-DOX) initiate the synthesis of oxylipins after bacterial infection. Here, the role of these enzymes in plants' defense was investigated using individual Arabidopsis thaliana lox1 and dox1 mutants and a double lox1 dox1 mutant. Studies with Pseudomonas syringae pv. tomato (Pst) revealed the enhanced susceptibility of lox1 to the virulent strain Pst DC3000 and the partial impairment of lox1 and dox1 mutants to activate systemic acquired resistance. Notably, both defects were enhanced in the lox1 dox1 plants as compared with individual mutants. We found that pre-treatment with 9-LOX- and α-DOX-generated oxylipins protected plant tissues against bacterial infection. The strongest effect in this respect was exerted by 9-ketooctadecatrienoic acid (9-KOT), which is produced from linolenic acid by 9-LOX. Quantification of 9-KOT revealed its accumulation after bacterial infection. The levels were reduced in lox1 and lox1 dox1 plants but strongly increased in the dox1 mutant due to metabolic interaction of the two pathways. Transcriptional analyses indicated that 9-KOT pre-treatment modifies hormone homeostasis during bacterial infection. The nature of the changes detected suggested that 9-KOT interferes with the hormonal changes caused by bacterial effectors. This notion was substantiated by the finding that 9-KOT failed to reduce the growth of PstDC3000hrpA, a mutant compromised in effector secretion, and of the avirulent strain Pst DC3000 avrRpm1. Further support for the action of the 9-LOX- and α-DOX-oxylipin pathways as modulators of hormone homeostasis was the observation that lox1 dox1 seedlings are hypersensitive to the growth-inhibitory effect of ABA and showed enhanced activation of ABA-inducible marker genes as compared with wild-type plants.

  14. Tryptophan degradation in irritable bowel syndrome: evidence of indoleamine 2,3-dioxygenase activation in a male cohort

    Directory of Open Access Journals (Sweden)

    Cryan John F

    2009-01-01

    Full Text Available Abstract Background Irritable bowel syndrome (IBS is a common disorder that affects 10–15% of the population. Although characterised by a lack of reliable biological markers, the disease state is increasingly viewed as a disorder of the brain-gut axis. In particular, accumulating evidence points to the involvement of both the central and peripheral serotonergic systems in disease symptomatology. Furthermore, altered tryptophan metabolism and indoleamine 2,3-dioxygenase (IDO activity are hallmarks of many stress-related disorders. The kynurenine pathway of tryptophan degradation may serve to link these findings to the low level immune activation recently described in IBS. In this study, we investigated tryptophan degradation in a male IBS cohort (n = 10 and control subjects (n = 26. Methods Plasma samples were obtained from patients and healthy controls. Tryptophan and its metabolites were measured by high performance liquid chromatography (HPLC and neopterin, a sensitive marker of immune activation, was measured using a commercially available ELISA assay. Results Both kynurenine levels and the kynurenine:tryptophan ratio were significantly increased in the IBS cohort compared with healthy controls. Neopterin was also increased in the IBS subjects and the concentration of the neuroprotective metabolite kynurenic acid was decreased, as was the kynurenic acid:kynurenine ratio. Conclusion These findings suggest that the activity of IDO, the immunoresponsive enzyme which is responsible for the degradation of tryptophan along this pathway, is enhanced in IBS patients relative to controls. This study provides novel evidence for an immune-mediated degradation of tryptophan in a male IBS population and identifies the kynurenine pathway as a potential source of biomarkers in this debilitating condition.

  15. Degradation of chloroaromatics : Purification and characterization of a novel type of chlorocatechol 2,3-dioxygenase of Pseudomonas putida GJ31

    NARCIS (Netherlands)

    Kaschabek, Stefan R.; Kasberg, Thomas; Müller, Dagmar; Mars, Astrid E.; Janssen, Dick B.; Reineke, Walter

    A purification procedure for a new kind of extradiol dioxygenase, termed chlorocatechol 2,3-dioxygenase, that converts 3-chlorocatechol productively was developed. Structural and kinetic properties of the enzyme, which is part of the degradative pathway used for growth of Pseudomonas putida GJ31

  16. Broad specificity dioxygenase enzymes and the bioremediation of hazardous aromatic pollutants

    International Nuclear Information System (INIS)

    Bonus, P.A.; Nies, L.

    1996-01-01

    The release of aromatic compounds to the environment is a major source of global pollution. In particular, the contamination of soil and groundwater with benzene, toluene, and xylenes (BTX) is the most ubiquitous form of aromatic pollution. The major source of BTX contamination is the release of gasoline and other petroleum products. This research focused on the improvement of bioremediation of BTX through a better understanding of broad specificity dioxygenase enzymes produced by soil and sediment bacteria. The investigation utilized pure bacterial strains isolated on biphenyl, naphthalene, or toluene. These isolated aerobic bacteria were then used to investigate the specificity of the initial enzymatic attack on aromatic compounds including BTX and polychlorinated biphenyls (PCBs). The enzymatic specificity and competency of the five isolates selected for study were determined through the use of growth tests and two rapid assay techniques. The growth tests were conducted on mineral agar plates or in liquid cultures, and they were used to determine substrate specificity. In addition, rapid assays for both BTX and PCBs were carried out using various growth substrates. These assays allowed further clarification of the specificity of the dioxygenase enzymes involved in aromatic degradation. Preliminary results of the PCB assay show that biphenyl and naphthalene isolated organisms grown on biphenyl, benzoate, naphthalene, and succinate maintain production of broad specificity dioxygenase enzymes able to degrade PCBs. Likewise, the BTX assay confirms that biphenyl and naphthalene selected organisms grown on their respective selection substrates completely degrade BTX including all three xylene isomers. In comparison, the toluene selected organism that was studied was unable to degrade PCBs, but it was able to degrade all BTX constituents

  17. A novel l-isoleucine-4?-dioxygenase and l-isoleucine dihydroxylation cascade in Pantoea ananatis

    OpenAIRE

    Smirnov, Sergey V; Sokolov, Pavel M; Kotlyarova, Veronika A; Samsonova, Natalya N; Kodera, Tomohiro; Sugiyama, Masakazu; Torii, Takayoshi; Hibi, Makoto; Shimizu, Sakayu; Yokozeki, Kenzo; Ogawa, Jun

    2013-01-01

    A unique operon structure has been identified in the genomes of several plant- and insect-associated bacteria. The distinguishing feature of this operon is the presence of tandem hilA and hilB genes encoding dioxygenases belonging to the PF13640 and PF10014 (BsmA) Pfam families, respectively. The genes encoding HilA and HilB from Pantoea ananatis AJ13355 were cloned and expressed in Escherichia coli. The culturing of E. coli cells expressing hilA (E. coli-HilA) or both hilA and hilB (E. coli-...

  18. Spontaneous cytotoxic T-Cell reactivity against indoleamine 2,3-dioxygenase-2

    DEFF Research Database (Denmark)

    Sørensen, Rikke Bæk; Køllgaard, Tania; Andersen, Rikke Sick

    2011-01-01

    Several lines of data have suggested a possible link between the indoleamine 2,3-dioxygenase (IDO)-like protein IDO2 and cancer. First, IDO2 expression has been described in human tumors, including renal, gastric, colon, and pancreatic tumors. Second, the apparent selective inhibition of IDO2...... in mouse models of cancer in a nontoxic fashion. Here, we describe the immunogenicity of IDO2 by showing the presence of spontaneous cytotoxic T-cell reactivity against IDO2 in peripheral blood of both healthy donors and cancer patients. Furthermore, we show that these IDO2-specific T cells are cytotoxic...

  19. 4-Hydroxyphenylpyruvate dioxygenase inhibitors in combination with safeners: solutions for modern and sustainable agriculture.

    Science.gov (United States)

    Ahrens, Hartmut; Lange, Gudrun; Müller, Thomas; Rosinger, Chris; Willms, Lothar; van Almsick, Andreas

    2013-09-02

    Inhibitors of 4-hydroxyphenylpyruvate dioxygenase (HPPD) prevent plant carotenoid pigment formation, which in turn leads to chlorophyll degradation. This "bleaching" herbicide mode of action provides weed-control products for various crops, such as rice, corn, and cereals. Combinations with suitable safeners allow the full exploitation of the potential of this compound class to selectively control major weed problems, including rapidly increasing cases of resistance against other important herbicide classes. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Compound-Specific Isotope Analysis of Nitroaromatic Contaminant Transformations by Nitroarene Dioxygenases

    Science.gov (United States)

    Pati, Sarah G.; Kohler, Hans-Peter E.; Hofstetter, Thomas B.

    2014-05-01

    Dioxygenation is an important biochemical reaction that often initiates the mineralization of recalcitrant organic contaminants such as nitroaromatic explosives, chlorinated benzenes, and polycyclic aromatic hydrocarbons. However, to assess the extent of dioxygenation in contaminated environments is difficult because of competing transformation processes and further reactions of the dioxygenation products. Compound-specific isotope analysis (CSIA) offers a new approach to reliably quantify biodegradation initiated by dioxygenation based on changes in stable isotope ratios of the pollutant. For CSIA it is essential to know the kinetic isotope effects (KIEs) pertinent to the dioxygenation mechanism of organic contaminants. Unfortunately, the range of KIEs of such reactions is poorly constrained although many dioxygenase enzymes with a broad substrate specificity have been reported. Dioxygenase enzymes usually exhibit complex reaction kinetics involving multiple substrates and substrate-specific binding modes which makes the determination of KIEs challenging. The goal of this study was to explore the magnitude and variability of 13C-, 2H-, and 15N-KIEs for the dioxygenation of one contaminant class, that is nitroaromatic contaminants (NACs). To this end, we investigated the C, H, and N isotope fractionation during the dioxygenation of nitrobenzene (NB), 2-nitrotoluene (2-NT), and 3-nitrotoluene (3-NT) by pure cultures, E. coli clones, cell extracts, and purified enzymes. From isotope fractionations measured in the substrates and reaction products, we determined dioxygenation KIEs for different combinations of the three substrates with nitrobenzene dioxygenase (NBDO) and 2-nitrotoluene dioxygenase (2NTDO). The 13C-, 2H-, and 15N-KIEs for the dioxygenation of NB by NBDO were consistent for all experimental systems considered (i.e., Comamonas sp. Strain JS765, E. coli clones, cell extracts of E. coli clones, and purified NBDO). This observation suggests that the isotope

  1. Molecular Characterization of the Genes pcaG and pcaH, Encoding Protocatechuate 3,4-Dioxygenase, Which Are Essential for Vanillin Catabolism in Pseudomonas sp. Strain HR199

    Science.gov (United States)

    Overhage, Jörg; Kresse, Andreas U.; Priefert, Horst; Sommer, Horst; Krammer, Gerhard; Rabenhorst, Jürgen; Steinbüchel, Alexander

    1999-01-01

    Pseudomonas sp. strain HR199 is able to utilize eugenol (4-allyl-2-methoxyphenol), vanillin (4-hydroxy-3-methoxybenzaldehyde), or protocatechuate as the sole carbon source for growth. Mutants of this strain which were impaired in the catabolism of vanillin but retained the ability to utilize eugenol or protocatechuate were obtained after nitrosoguanidine mutagenesis. One mutant (SK6169) was used as recipient of a Pseudomonas sp. strain HR199 genomic library in cosmid pVK100, and phenotypic complementation was achieved with a 5.8-kbp EcoRI fragment (E58). The amino acid sequences deduced from two corresponding open reading frames (ORF) identified on E58 revealed high degrees of homology to pcaG and pcaH, encoding the two subunits of protocatechuate 3,4-dioxygenase. Three additional ORF most probably encoded a 4-hydroxybenzoate 3-hydroxylase (PobA) and two putative regulatory proteins, which exhibited homology to PcaQ of Agrobacterium tumefaciens and PobR of Pseudomonas aeruginosa, respectively. Since mutant SK6169 was also complemented by a subfragment of E58 that harbored only pcaH, this mutant was most probably lacking a functional β subunit of the protocatechuate 3,4-dioxygenase. Since this mutant was still able to grow on protocatechuate and lacked protocatechuate 4,5-dioxygenase and protocatechuate 2,3-dioxygenase, the degradation had to be catalyzed by different enzymes. Two other mutants (SK6184 and SK6190), which were also impaired in the catabolism of vanillin, were not complemented by fragment E58. Since these mutants accumulated 3-carboxy muconolactone during cultivation on eugenol, they most probably exhibited a defect in a step of the catabolic pathway following the ortho cleavage. Moreover, in these mutants cyclization of 3-carboxymuconic acid seems to occur by a syn absolute stereochemical course, which is normally only observed for cis,cis-muconate lactonization in pseudomonads. In conclusion, vanillin is degraded through the ortho-cleavage pathway

  2. Catalytic Mechanism of Salicylate Dioxygenase: QM/MM Simulations Reveal the Origin of Unexpected Regioselectivity of the Ring Cleavage.

    Science.gov (United States)

    Roy, Subhendu; Kästner, Johannes

    2017-07-03

    Salicylate 1,2-dioxygenase (SDO) was the first enzyme discovered, in the family of iron dioxygenases, to catalyze the ring cleavage of a monohydroxylated aromatic compound, salicylate, without a proton donor. Salicylate is not electron-rich like the familiar dihydroxy or aromatic substrates with an electron-donating group that are utilized in the well-known dioxygenases. SDO carries out the intramolecular C-C bond cleavage in salicylate bearing the OH and COOH groups with high regioselectivity in comparison with the extradiol and intradiol dioxygenases. The catalytic cleavage of a nonactivated substrate like salicylate that lacks an electron-donating group, also in the absence of a proton source, raises many puzzling questions about the oxy intermediates in the reaction pathway of dioxygenase enzymes in general. To answer these fundamental queries, we have investigated the full catalytic mechanism of SDO by a combination of quantum mechanics and molecular mechanics (QM/MM) calculations. Herein, our QM/MM study has several unexpected and interesting implications for the mechanistic pathway of SDO in comparison to the experimental observations. Importantly, it unravels the basis for the unexpected "intra"-cleavage regioselectivity in SDO. Ostensibly a similar alkylperoxo intermediate is formed in SDO much like in the extradiol and intradiol dioxygenases. In stark contrast to the two diol enzymes, the O-O bond breaking leads to an unprotonated gem-hydroxy carboxylate intermediate, a paradigm analogue of the elusive gem diol intermediate. This unprotonated gem-hydroxy carboxylate intermediate exclusively dictates the C-C cleavage regiospecificity in SDO, which is unprecedented in the family of dioxygenases. It forms a seven-membered lactone species, which eventually forms the ring-cleavage final product by incorporation of two oxygen atoms in the salicylate. Thus, our computational study unravels a detailed reaction pathway of the oxidative cleavage of salicylate

  3. Genetic Analysis of Dioxin Dioxygenase of Sphingomonas sp. Strain RW1: Catabolic Genes Dispersed on the Genome

    OpenAIRE

    Armengaud, Jean; Happe, Birgitta; Timmis, Kenneth N.

    1998-01-01

    The dioxin dioxygenase of Sphingomonas sp. strain RW1 activates dibenzo-p-dioxin and dibenzofuran for further metabolism by introducing two atoms of oxygen at a pair of vicinal carbon atoms, one of which is involved in one of the bridges between the two aromatic rings, i.e., an angular dioxygenation. The dxnA1 and dxnA2 cistrons encoding this dioxygenase have been cloned and shown to be located just upstream of a hydrolase gene which specifies an enzyme involved in the subsequent step of the ...

  4. First report of a deletion encompassing an entire exon in the homogentisate 1,2-dioxygenase gene causing alkaptonuria.

    Science.gov (United States)

    Zouheir Habbal, Mohammad; Bou-Assi, Tarek; Zhu, Jun; Owen, Renius; Chehab, Farid F

    2014-01-01

    Alkaptonuria is often diagnosed clinically with episodes of dark urine, biochemically by the accumulation of peripheral homogentisic acid and molecularly by the presence of mutations in the homogentisate 1,2-dioxygenase gene (HGD). Alkaptonuria is invariably associated with HGD mutations, which consist of single nucleotide variants and small insertions/deletions. Surprisingly, the presence of deletions beyond a few nucleotides among over 150 reported deleterious mutations has not been described, raising the suspicion that this gene might be protected against the detrimental mechanisms of gene rearrangements. The quest for an HGD mutation in a proband with AKU revealed with a SNP array five large regions of homozygosity (5-16 Mb), one of which includes the HGD gene. A homozygous deletion of 649 bp deletion that encompasses the 72 nucleotides of exon 2 and surrounding DNA sequences in flanking introns of the HGD gene was unveiled in a proband with AKU. The nature of this deletion suggests that this in-frame deletion could generate a protein without exon 2. Thus, we modeled the tertiary structure of the mutant protein structure to determine the effect of exon 2 deletion. While the two β-pleated sheets encoded by exon 2 were missing in the mutant structure, other β-pleated sheets are largely unaffected by the deletion. However, nine novel α-helical coils substituted the eight coils present in the native HGD crystal structure. Thus, this deletion results in a deleterious enzyme, which is consistent with the proband's phenotype. Screening for mutations in the HGD gene, particularly in the Middle East, ought to include this exon 2 deletion in order to determine its frequency and uncover its origin.

  5. Indoleamine 2,3-dioxygenase-expressing myeloid dendritic cells and macrophages in infectious and noninfectious cutaneous granulomas.

    Science.gov (United States)

    von Bubnoff, Dagmar; Scheler, Marina; Wilms, Helene; Wenzel, Jörg; von Bubnoff, Nikolas; Häcker, Georg; Schultze, Joachim; Popov, Alexey; Racz, Paul; Bieber, Thomas; Wickenhauser, Claudia

    2011-10-01

    The enzyme indoleamine 2,3-dioxygenase (IDO) degrades the essential amino acid tryptophan, and this degradation is an immunosuppressive mechanism that is mainly used by antigen-presenting cells. IDO-expressing dendritic cells and macrophages have previously been identified as components of lymph node granulomas after Listeria monocytogenes infection. In this study we undertook an analysis of IDO expression in granulomas of infectious and noninfectious origin in the human skin. Lesional skin biopsy specimens (n = 22) from different granulomatous skin disorders (lupus vulgaris, sarcoidosis, granuloma annulare, leprosy) were analyzed. Immunohistochemistry was performed to identify and locate the enzyme IDO within the inflammatory granulomatous infiltrate (IDO, CD11c, CD68, S100, CD3, Foxp3). Two-color immunofluorescence of IDO in combination with multiple markers was applied to characterize the IDO-expressing cells. Cutaneous granulomas of different origin strongly express IDO, mainly in the center and in the ring wall of the granulomas. We demonstrate that in infectious, but also in noninfectious human cutaneous granulomas the large myeloid CD11c(+)S100(+)CD68(-) dendritic cells and the CD68(+) macrophages express IDO. This study was limited by the lack of details about the exact stage or maturity of granuloma formation in the specimens investigated. These findings reveal that IDO expression in myeloid dendritic cells and macrophages is part of an integrated response of granuloma formation, which may be a unifying feature of granulomatous reactions in the skin. Copyright © 2010 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.

  6. Single turnover of substrate-bound ferric cysteine dioxygenase with superoxide anion: enzymatic reactivation, product formation, and a transient intermediate.

    Science.gov (United States)

    Crawford, Joshua A; Li, Wei; Pierce, Brad S

    2011-11-29

    Cysteine dioxygenase (CDO) is a non-heme mononuclear iron enzyme that catalyzes the O(2)-dependent oxidation of L-cysteine (Cys) to produce cysteine sulfinic acid (CSA). In this study we demonstrate that the catalytic cycle of CDO can be "primed" by one electron through chemical oxidation to produce CDO with ferric iron in the active site (Fe(III)-CDO, termed 2). While catalytically inactive, the substrate-bound form of Fe(III)-CDO (2a) is more amenable to interrogation by UV-vis and EPR spectroscopy than the 'as-isolated' Fe(II)-CDO enzyme (1). Chemical-rescue experiments were performed in which superoxide (O(2)(•-)) anions were introduced to 2a to explore the possibility that a Fe(III)-superoxide species represents the first intermediate within the catalytic pathway of CDO. In principle, O(2)(•-) can serve as a suitable acceptor for the remaining 3-electrons necessary for CSA formation and regeneration of the active Fe(II)-CDO enzyme (1). Indeed, addition of O(2)(•-) to 2a resulted in the rapid formation of a transient species (termed 3a) observable at 565 nm by UV-vis spectroscopy. The subsequent decay of 3a is kinetically matched to CSA formation. Moreover, a signal attributed to 3a was also identified using parallel mode X-band EPR spectroscopy (g ~ 11). Spectroscopic simulations, observed temperature dependence, and the microwave power saturation behavior of 3a are consistent with a ground state S = 3 from a ferromagnetically coupled (J ~ -8 cm(-1)) high-spin ferric iron (S(A) = 5/2) with a bound radical (S(B) = 1/2), presumably O(2)(•-). Following treatment with O(2)(•-), the specific activity of recovered CDO increased to ~60% relative to untreated enzyme.

  7. Synergistic Substrate and Oxygen Activation in Salicylate Dioxygenase Revealed by QM/MM Simulations.

    Science.gov (United States)

    Roy, Subhendu; Kästner, Johannes

    2016-01-18

    Salicylate 1,2-dioxygenase (SDO) is the first enzyme to be discovered to catalyze the oxidative cleavage of a monohydroxylated aromatic compound, namely salicylate, instead of the well-known electron-rich substrates. We have investigated the mechanism of dioxygen activation in SDO by QM/MM calculations. Our study reveals that the non-heme Fe(II) center in SDO activates salicylate and O2 synergistically through a strong covalent interaction to facilitate the reductive cleavage of O2. A covalent salicylate-Fe(II) -O2 complex is the reactive oxygen species in this case, and its electronic structure is best described as being between the two limiting cases, Fe(II)-O2 and Fe(II)-O2˙(-), with partial electron transfer from the activated salicylate to O2 via the Fe center. Thus SDO employs a synergistic strategy of substrate and oxygen activation to carry out the catalytic reaction, which is unprecedented in the family of iron dioxygenases. Moreover, O2 activation in SDO happens without the assistance of a proton source. Our study essentially shows a new mechanistic possibility for O2 activation. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Different Mechanisms of Catalytic Complex Formation in Two L-Tryptophan Processing Dioxygenases

    Directory of Open Access Journals (Sweden)

    Karin Nienhaus

    2018-01-01

    Full Text Available The human heme enzymes tryptophan 2,3-dioxygenase (hTDO and indoleamine 2,3 dioxygenase (hIDO catalyze the initial step in L-tryptophan (L-Trp catabolism, the insertion of dioxygen into L-Trp. Overexpression of these enzymes causes depletion of L-Trp and accumulation of metabolic products, and thereby contributes to tumor immune tolerance and immune dysregulation in a variety of disease pathologies. Understanding the assembly of the catalytically active, ternary enzyme-substrate-ligand complexes is not yet fully resolved, but an essential prerequisite for designing efficient and selective de novo inhibitors. Evidence is mounting that the ternary complex forms by sequential binding of ligand and substrate in a specific order. In hTDO, the apolar L-Trp binds first, decreasing active-site solvation and, as a result, reducing non-productive oxidation of the heme iron by the dioxygen ligand, which may leave the substrate bound to a ferric heme iron. In hIDO, by contrast, dioxygen must first coordinate to the heme iron because a bound substrate would occlude ligand access to the heme iron, so the ternary complex can no longer form. Consequently, faster association of L-Trp at high concentrations results in substrate inhibition. Here, we summarize our present knowledge of ternary complex formation in hTDO and hIDO and relate these findings to structural peculiarities of their active sites.

  9. Purification and partial characterization of the extradiol dioxygenase, 2'-carboxy-2,3-dihydroxybiphenyl 1,2-dioxygenase, in the fluorene degradation pathway from Rhodococcus sp. strain DFA3.

    Science.gov (United States)

    Kotake, Tatsuro; Matsuzawa, Jun; Suzuki-Minakuchi, Chiho; Okada, Kazunori; Nojiri, Hideaki; Iwata, Kenichi

    2016-01-01

    Type II extradiol dioxygenase, 2'-carboxy-2,3-dihydroxybiphenyl 1,2-dioxygenase (FlnD1D2) involved in the fluorene degradation pathway of Rhodococcus sp. DFA3 was purified to homogeneity from a heterologously expressing Escherichia coli. Gel filtration chromatography and SDS-PAGE suggested that FlnD1D2 is an α4β4 heterooctamer and that the molecular masses of these subunits are 30 and 9.9 kDa, respectively. The optimum pH and temperature for enzyme activity were 8.0 and 30 °C, respectively. Assessment of metal ion effects suggested that exogenously supplied Fe(2+) increases enzyme activity 3.2-fold. FlnD1D2 catalyzed meta-cleavage of 2'-carboxy-2,3-dihydroxybiphenyl homologous compounds, but not single-ring catecholic compounds. The Km and kcat/Km values of FlnD1D2 for 2,3-dihidroxybiphenyl were 97.2 μM and 1.5 × 10(-2) μM(-1)sec(-1), and for 2,2',3-trihydroxybiphenyl, they were 168.0 μM and 0.5 × 10(-2) μM(-1)sec(-1), respectively. A phylogenetic tree of the large and small subunits of type II extradiol dioxygenases suggested that FlnD1D2 constitutes a novel subgroup among heterooligomeric type II extradiol dioxygenases.

  10. Indoleamine 2,3-dioxygenase-dependent tryptophan metabolites contribute to tolerance induction during allergen immunotherapy in a mouse model

    NARCIS (Netherlands)

    Taher, Yousef A.; Piavaux, Benoit J. A.; Gras, Renee; van Esch, Betty C. A. M.; Hofman, Gerard A.; Bloksma, Nanne; Henricks, Paul A. J.; van Oosterhout, Antoon J. M.

    Background: The tryptophan-catabolizing enzyme indoleamine 2,3-dioxygenase (IDO) has been implicated in immune suppression and tolerance induction. Objective: We examined (1) whether IDO activity is required during tolerance induction by allergen immunotherapy or for the subsequent suppressive

  11. Indoleamine 2,3-dioxygenase and survivin peptide vaccine combined with temozolomide in metastatic melanoma

    DEFF Research Database (Denmark)

    Nitschke, Nikolaj Juul; Bjoern, Jon; Iversen, Trine Zeeberg

    2017-01-01

    BACKGROUND: Indoleamine 2,3-dioxygenase (IDO) and survivin have been identified as potential targets for cancer vaccination. In this phase II study a vaccine using the peptides Sur1M2 and IDO5 was combined with the chemotherapy temozolomide (TMZ) for treatment of metastatic melanoma patients....... The aim was to simultaneously target several immune inhibiting mechanisms and the highly malignant cells expressing survivin. METHODS: HLA-A2 positive patients with advanced malignant melanoma were treated biweekly with 150 mg/m2 TMZ daily for 7 days followed by subcutaneous vaccination with 250 µg...... of each peptide in 500 µL Montanide solution at day 8. Granulocyte-macrophage colony-stimulating factor was used as an adjuvant and topical imiquimod was applied prior to vaccination. Treatment was continued until disease progression. Clinical response was evaluated by PET-CT and immunological outcome...

  12. Targeting the immunoregulatory indoleamine 2,3 dioxygenase pathway in immunotherapy

    Science.gov (United States)

    Johnson, Burles A; Baban, Babak; Mellor, Andrew L

    2009-01-01

    Natural immune tolerance is a formidable barrier to successful immunotherapy to treat established cancers and chronic infections. Conversely, creating robust immune tolerance via immunotherapy is the major goal in treating autoimmune and allergic diseases, and enhancing survival of transplanted organs and tissues. In this review, we focus on a natural mechanism that creates local T-cell tolerance in many clinically relevant settings of chronic inflammation involving expression of the cytosolic enzyme indoleamine 2,3-dioxygenase (IDO) by specialized subsets of dendritic cells. IDO-expressing dendritic cells suppress antigen-specific T-cell responses directly, and induce bystander suppression by activating regulatory T cells. Thus, manipulating IDO is a promising strategy to treat a range of chronic inflammatory diseases. PMID:20161103

  13. Indoleamine 2,3-dioxygenase specific, cytotoxic T cells as immune regulators

    DEFF Research Database (Denmark)

    Sørensen, Rikke Bæk; Hadrup, Sine Reker; Svane, Inge Marie

    2011-01-01

    Indoleamine 2,3-dioxygenase (IDO) is an immunoregulatory enzyme that is implicated in suppressing T-cell immunity in normal and pathologic settings. Here, we describe that spontaneous cytotoxic T-cell reactivity against IDO exists not only in patients with cancer but also in healthy persons. We...... show that the presence of such IDO-specific CD8(+) T cells boosted T-cell immunity against viral or tumor-associated antigens by eliminating IDO+ suppressive cells. This had profound effects on the balance between interleukin-17 (IL-17)-producing CD4(+) T cells and regulatory T cells. Furthermore....... We describe for the first time effector T cells with a general regulatory function that may play a vital role for the mounting or maintaining of an effective adaptive immune response. We suggest terming such effector T cells "supporter T cells." (Blood. 2011;117(7):2200-2210)...

  14. Degradation of benzotrifluoride via the dioxygenase pathway in Rhodococcus sp. 065240.

    Science.gov (United States)

    Yano, Kenichi; Wachi, Masaaki; Tsuchida, Sakiko; Kitazume, Tomoya; Iwai, Noritaka

    2015-01-01

    We previously isolated Rhodococcus sp. 065240, which catalyzes the defluorination of benzotrifluoride (BTF). In order to investigate the mechanism of this degradation of BTF, we performed proteomic analysis of cells grown with or without BTF. Three proteins, which resemble dioxygenase pathway enzymes responsible for isopropylbenzene degradation from Rhodococcus erythropolis BD2, were induced by BTF. Genomic PCR and DNA sequence analysis revealed that the Rhodococcus sp. 065240 carries the gene cluster, btf, which is highly homologous to the ipb gene cluster from R. erythropolis BD2. A mutant strain, which could not catalyze BTF defluorination, was isolated from 065240 strain by UV mutagenesis. The mutant strain had one mutation in the btfT gene, which encodes a response regulator of the two component system. The defluorinating ability of the mutant strain was recovered by complementation of btfT. These results suggest that the btf gene cluster is responsible for degradation of BTF.

  15. Indoleamine 2,3-dioxygenase promotes peritoneal metastasis of ovarian cancer by inducing an immunosuppressive environment.

    Science.gov (United States)

    Tanizaki, Yuko; Kobayashi, Aya; Toujima, Saori; Shiro, Michihisa; Mizoguchi, Mika; Mabuchi, Yasushi; Yagi, Shigetaka; Minami, Sawako; Takikawa, Osamu; Ino, Kazuhiko

    2014-08-01

    Indoleamine 2,3-dioxygenase (IDO) is a tryptophan-catabolizing enzyme that has immunoregulatory functions. Our prior study showed that tumoral IDO overexpression is involved in disease progression and impaired patient survival in human ovarian cancer, although its mechanism remains unclear. The purpose of the present study is to clarify the role of IDO during the process of peritoneal dissemination of ovarian cancer. Indoleamine 2,3-dioxygenase cDNA was transfected into the murine ovarian carcinoma cell line OV2944-HM-1, establishing stable clones of IDO-overexpressing cells (HM-1-IDO). Then HM-1-IDO or control vector-transfected cells (HM-1-mock) were i.p. transplanted into syngeneic immunocompetent mice. The HM-1-IDO-transplanted mice showed significantly shortened survival compared with HM-1-mock-transplanted (control) mice. On days 11 and 14 following transplantation, the tumor weight of peritoneal dissemination and ascites volume were significantly increased in HM-1-IDO-transplanted mice compared with those of control mice. This tumor-progressive effect was coincident with significantly reduced numbers of CD8(+) T cells and natural killer cells within tumors as well as increased levels of transforming growth factor-β and interleukin-10 in ascites. Finally, treatment with the IDO inhibitor 1-methyl-tryptophan significantly suppressed tumor dissemination and ascites with reduced transforming growth factor-β secretion. These findings showed that tumor-derived IDO promotes the peritoneal dissemination of ovarian cancer through suppression of tumor-infiltrating effector T cell and natural killer cell recruitment and reciprocal enhancement of immunosuppressive cytokines in ascites, creating an immunotolerogenic environment within the peritoneal cavity. Therefore, IDO may be a promising molecular target for the therapeutic strategy of ovarian cancer. © 2014 The Authors. Cancer Science published by Wiley Publishing Asia Pty Ltd on behalf of Japanese Cancer

  16. Functional Metagenomics of a Biostimulated Petroleum-Contaminated Soil Reveals an Extraordinary Diversity of Extradiol Dioxygenases.

    Science.gov (United States)

    Terrón-González, Laura; Martín-Cabello, Guadalupe; Ferrer, Manuel; Santero, Eduardo

    2016-04-01

    A metagenomic library of a petroleum-contaminated soil was constructed in a fosmid vector that allowed heterologous expression of metagenomic DNA. The library, consisting of 6.5 Gb of metagenomic DNA, was screened for extradiol dioxygenase (Edo) activity using catechol and 2,3-dihydroxybiphenyl as the substrates. Fifty-eight independent clones encoding extradiol dioxygenase activity were identified. Forty-one different Edo-encoding genes were identified. The population of Edo genes was not dominated by a particular gene or by highly similar genes; rather, the genes had an even distribution and high diversity. Phylogenetic analyses revealed that most of the genes could not be ascribed to previously defined subfamilies of Edos. Rather, the Edo genes led to the definition of 10 new subfamilies of type I Edos. Phylogenetic analysis of type II enzymes defined 7 families, 2 of which harbored the type II Edos that were found in this work. Particularly striking was the diversity found in family I.3 Edos; 15 out of the 17 sequences assigned to this family belonged to 7 newly defined subfamilies. A strong bias was found that depended on the substrate used for the screening: catechol mainly led to the detection of Edos belonging to the I.2 family, while 2,3-dihydroxybiphenyl led to the detection of most other Edos. Members of the I.2 family showed a clear substrate preference for monocyclic substrates, while those from the I.3 family showed a broader substrate range and high activity toward 2,3-dihydroxybiphenyl. This metagenomic analysis has substantially increased our knowledge of the existing biodiversity of Edos. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  17. Degradation of phenanthrene and pyrene using genetically engineered dioxygenase producing Pseudomonas putida in soil

    Directory of Open Access Journals (Sweden)

    Mardani Gashtasb

    2016-01-01

    Full Text Available Bioremediation use to promote degradation and/or removal of contaminants into nonhazardous or less-hazardous substances from the environment using microbial metabolic ability. Pseudomonas spp. is one of saprotrophic soil bacterium and can be used for biodegradation of polycyclic aromatic hydrocarbons (PAHs but this activity in most species is weak. Phenanthrene and pyrene could associate with a risk of human cancer development in exposed individuals. The aim of the present study was application of genetically engineered P. putida that produce dioxygenase for degradation of phenanthrene and pyrene in spiked soil using high-performance liquid chromatography (HPLC method. The nahH gene that encoded catechol 2,3-dioxygenase (C23O was cloned into pUC18 and pUC18-nahH recombinant vector was generated and transformed into wild P. putida, successfully. The genetically modified and wild types of P. putida were inoculated in soil and pilot plan was prepared. Finally, degradation of phenanthrene and pyrene by this bacterium in spiked soil were evaluated using HPLC measurement technique. The results were showed elimination of these PAH compounds in spiked soil by engineered P. putida comparing to dishes containing natural soil with normal microbial flora and inoculated autoclaved soil by wild type of P. putida were statistically significant (p0.05 but it was few impact on this process (more than 2%. Additional and verification tests including catalase, oxidase and PCR on isolated bacteria from spiked soil were indicated that engineered P. putida was alive and functional as well as it can affect on phenanthrene and pyrene degradation via nahH gene producing. These findings indicated that genetically engineered P. putida generated in this work via producing C23O enzyme can useful and practical for biodegradation of phenanthrene and pyrene as well as petroleum compounds in polluted environments.

  18. Indoleamine 2,3-dioxygenase-expressing leukemic dendritic cells impair a leukemia-specific immune response by inducing potent T regulatory cells.

    Science.gov (United States)

    Curti, Antonio; Trabanelli, Sara; Onofri, Chiara; Aluigi, Michela; Salvestrini, Valentina; Ocadlikova, Darina; Evangelisti, Cecilia; Rutella, Sergio; De Cristofaro, Raimondo; Ottaviani, Emanuela; Baccarani, Michele; Lemoli, Roberto M

    2010-12-01

    The immunoregulatory enzyme indoleamine 2,3-dioxygenase, which catalyzes the conversion of tryptophan into kynurenine, is expressed in a significant subset of patients with acute myeloid leukemia, resulting in the inhibition of T-cell proliferation and the induction of regulatory T cells. Acute myeloid leukemia cells can be differentiated into dendritic cells, which have increased immunogenicity and have been proposed as vaccines against leukemia. Leukemic dendritic cells were generated from acute myeloid leukemia cells and used as stimulators in functional assays, including the induction of regulatory T cells. Indoleamine 2,3-dioxygenase expression in leukemic dendritic cells was evaluated at molecular, protein and enzymatic levels. We demonstrate that, after differentiation into dendritic cells, both indoleamine 2,3-dioxygenase-negative and indoleamine 2,3-dioxygenase-positive acute myeloid leukemia samples show induction and up-regulation of indoleamine 2,3-dioxygenase gene and protein, respectively. Indoleamine 2,3-dioxygenase-positive acute myeloid leukemia dendritic cells catabolize tryptophan into kynurenine metabolite and inhibit T-cell proliferation through an indoleamine 2,3-dioxygenase-dependent mechanism. Moreover, indoleamine 2,3-dioxygenase-positive leukemic dendritic cells increase the number of allogeneic and autologous CD4(+)CD25(+) Foxp3(+) T cells and this effect is completely abrogated by the indoleamine 2,3-dioxygenase-inhibitor, 1-methyl tryptophan. Purified CD4(+)CD25(+) T cells obtained from co-culture with indoleamine 2,3-dioxygenase-positive leukemic dendritic cells act as regulatory T cells as they inhibit naive T-cell proliferation and impair the complete maturation of normal dendritic cells. Importantly, leukemic dendritic cell-induced regulatory T cells are capable of in vitro suppression of a leukemia-specific T cell-mediated immune response, directed against the leukemia-associated antigen, Wilms' tumor protein. These data identify

  19. Structure of the Dioxygenase AsqJ: Mechanistic Insights into a One-Pot Multistep Quinolone Antibiotic Biosynthesis

    KAUST Repository

    Bräuer, Alois

    2015-11-10

    © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. Multienzymatic cascades are responsible for the biosynthesis of natural products and represent a source of inspiration for synthetic chemists. The FeII/α-ketoglutarate-dependent dioxygenase AsqJ from Aspergillus nidulans is outstanding because it stereoselectively catalyzes both a ferryl-induced desaturation reaction and epoxidation on a benzodiazepinedione. Interestingly, the enzymatically formed spiro epoxide spring-loads the 6,7-bicyclic skeleton for non-enzymatic rearrangement into the 6,6-bicyclic scaffold of the quinolone alkaloid 4′-methoxyviridicatin. Herein, we report different crystal structures of the protein in the absence and presence of synthesized substrates, surrogates, and intermediates that mimic the various stages of the reaction cycle of this exceptional dioxygenase.

  20. Tryptophan 2,3-dioxygenase (TDO)-reactive T cells differ in their functional characteristics in health and cancer

    DEFF Research Database (Denmark)

    Hjortsø, Mads Duus; Larsen, Stine Kiaer; Kongsted, Per

    2015-01-01

    Tryptophan-2,3-dioxygenase (TDO) physiologically regulates systemic tryptophan levels in the liver. However, numerous studies have linked cancer with activation of local and systemic tryptophan metabolism. Indeed, similar to other heme dioxygenases TDO is constitutively expressed in many cancers....... In the present study, we detected the presence of both CD8(+) and CD4(+) T-cell reactivity toward TDO in peripheral blood of patients with malignant melanoma (MM) or breast cancer (BC) as well as healthy subjects. However, TDO-reactive CD4(+) T cells constituted distinct functional phenotypes in health...... and disease. In healthy subjects these cells predominately comprised interferon (IFN)γ and tumor necrosis factor (TNF)-α producing Th1 cells, while in cancer patients TDO-reactive CD4(+) T-cells were more differentiated with release of not only IFNγ and TNFα, but also interleukin (IL)-17 and IL-10 in response...

  1. Atom Tunneling in the Hydroxylation Process of Taurine/α-Ketoglutarate Dioxygenase Identified by Quantum Mechanics/Molecular Mechanics Simulations.

    Science.gov (United States)

    Álvarez-Barcia, Sonia; Kästner, Johannes

    2017-06-01

    Taurine/α-ketoglutarate dioxygenase is one of the most studied α-ketoglutarate-dependent dioxygenases (αKGDs), involved in several biotechnological applications. We investigated the key step in the catalytic cycle of the αKGDs, the hydrogen transfer process, by a quantum mechanics/molecular mechanics approach (B3LYP/CHARMM22). Analysis of the charge and spin densities during the reaction demonstrates that a concerted mechanism takes place, where the H atom transfer happens simultaneously with the electron transfer from taurine to the Fe═O cofactor. We found the quantum tunneling of the hydrogen atom to increase the rate constant by a factor of 40 at 5 °C. As a consequence, a quite high kinetic isotope effect close to 60 is obtained, which is consistent with the experimental value.

  2. Molecular dynamics simulations of Hsp40 J-domain mutants identifies disruption of the critical HPD-motif as the key factor for impaired curing in vivo of the yeast prion [URE3].

    Science.gov (United States)

    Xue, You-Lin; Wang, Hao; Riedy, Michael; Roberts, Brittany-Lee; Sun, Yuna; Song, Yong-Bo; Jones, Gary W; Masison, Daniel C; Song, Youtao

    2018-05-01

    Genetic screens using Saccharomyces cerevisiae have identified an array of Hsp40 (Ydj1p) J-domain mutants that are impaired in the ability to cure the yeast [URE3] prion through disrupting functional interactions with Hsp70. However, biochemical analysis of some of these Hsp40 J-domain mutants has so far failed to provide major insight into the specific functional changes in Hsp40-Hsp70 interactions. To explore the detailed structural and dynamic properties of the Hsp40 J-domain, 20 ns molecular dynamic simulations of 4 mutants (D9A, D36A, A30T, and F45S) and wild-type J-domain were performed, followed by Hsp70 docking simulations. Results demonstrated that although the Hsp70 interaction mechanism of the mutants may vary, the major structural change was targeted to the critical HPD motif of the J-domain. Our computational analysis fits well with previous yeast genetics studies regarding highlighting the importance of J-domain function in prion propagation. During the molecular dynamics simulations several important residues were identified and predicted to play an essential role in J-domain structure. Among these residues, Y26 and F45 were confirmed, using both in silico and in vivo methods, as being critical for Ydj1p function.

  3. Indoleamine 2,3-dioxygenase 1 (IDO1) activity correlates with immune system abnormalities in multiple myeloma

    OpenAIRE

    Bonanno Giuseppina; Mariotti Andrea; Procoli Annabella; Folgiero Valentina; Natale Daniela; De Rosa Luca; Majolino Ignazio; Novarese Linda; Rocci Alberto; Gambella Manuela; Ciciarello Marilena; Scambia Giovanni; Palumbo Antonio; Locatelli Franco; De Cristofaro Raimondo

    2012-01-01

    Abstract Background Multiple myeloma (MM) is a plasma cell malignancy with a multifaceted immune dysfunction. Indoleamine 2,3-dioxygenase 1 (IDO1) degrades tryptophan into kynurenine (KYN), which inhibits effector T cells and promote regulatory T-cell (Treg) differentiation. It is presently unknown whether MM cells express IDO1 and whether IDO1 activity correlates with immune system impairment. Methods We investigated IDO1 expression in 25 consecutive patients with symptomatic MM and in 7 pat...

  4. Diversity of extradiol dioxygenases in aromatic-degrading microbial community explored using both culture-dependent and culture-independent approaches.

    Science.gov (United States)

    Suenaga, Hikaru; Mizuta, Shiori; Miyazaki, Kentaro; Yaoi, Katsuro

    2014-11-01

    Culture-dependent and culture-independent approaches were used for extensive retrieval of the extradiol dioxygenase (EDO) gene from the environment to investigate the relationship between the EDO genes from isolated bacteria and the metagenomic EDO genes from which they were isolated. In our previous study, we identified 91 fosmid clones showing EDO enzyme activity using a metagenomic approach. In the present study, we classified all these metagenome-derived EDOs and newly isolated 88 phenol-utilizing bacteria from the same sample and identified four EDO genes from them. Of these, two EDOs had amino acid sequences similar to those reported previously in aromatic-utilizing strains, and one EDO had a sequence almost identical to that of metagenomic EDOs identified in our previous study. Unexpectedly, one EDO showed no similarity to any class I EDOs and was categorized as class II, which has not been found in past metagenomic approaches. Quantitative polymerase chain reaction (PCR) assay indicated that the low-abundance class II EDO gene can be enriched by culturing approaches. We conclude that the combined use of the two approaches can explore the gene community more extensively than their individual use. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  5. Preparation, Crystallization and X-ray Diffraction Analysis to 1.5 A Resolution of Rat Cysteine Dioxygenase, a Mononuclear Iron Enzyme Responsible for Cysteine Thiol Oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Simmons,C.; Hao, Q.; Stipanuk, M.

    2005-01-01

    Cysteine dioxygenase (CDO; EC 1.13.11.20) is an {approx}23 kDa non-heme iron metalloenzyme that is responsible for the oxidation of cysteine by O2, yielding cysteinesulfinate. CDO catalyzes the first step in the conversion of cysteine to taurine, as well as the first step in the catabolism of cysteine to pyruvate plus sulfate. Recombinant rat CDO was heterologously expressed, purified and crystallized. The protein was expressed as a fusion protein bearing a polyhistidine tag to facilitate purification, a thioredoxin tag to improve solubility and a factor Xa cleavage site to permit removal of the entire N-terminus, leaving only the 200 amino acids inherent to the native protein. A multi-step purification scheme was used to achieve >95% purity of CDO. The optimal CDO crystals diffracted to 1.5 Angstroms resolution and belonged to space group P4{sub 3}2{sub 1}2 or P4{sub 1}2{sub 1}2, with unit-cell parameters a = b = 57.55, c = 123.06 Angstrom, {alpha} = {beta} = {gamma} = 90. CDO shows little homology to any other proteins; therefore, the structure of the enzyme will be determined by ab initio phasing using a selenomethionyl derivative.

  6. Characterization of the Promoter Region of an Arabidopsis Gene for 9-cis-Epoxycarotenoid Dioxygenase Involved in Dehydration-Inducible Transcription

    Science.gov (United States)

    Behnam, Babak; Iuchi, Satoshi; Fujita, Miki; Fujita, Yasunari; Takasaki, Hironori; Osakabe, Yuriko; Yamaguchi-Shinozaki, Kazuko; Kobayashi, Masatomo; Shinozaki, Kazuo

    2013-01-01

    Plants respond to dehydration stress and tolerate water-deficit status through complex physiological and cellular processes. Many genes are induced by water deficit. Abscisic acid (ABA) plays important roles in tolerance to dehydration stress by inducing many stress genes. ABA is synthesized de novo in response to dehydration. Most of the genes involved in ABA biosynthesis have been identified, and they are expressed mainly in leaf vascular tissues. Of the products of such genes, 9-cis-epoxycarotenoid dioxygenase (NCED) is a key enzyme in ABA biosynthesis. One of the five NCED genes in Arabidopsis, AtNCED3, is significantly induced by dehydration. To understand the regulatory mechanism of the early stages of the dehydration stress response, it is important to analyse the transcriptional regulatory systems of AtNCED3. In the present study, we found that an overlapping G-box recognition sequence (5′-CACGTG-3′) at −2248 bp from the transcriptional start site of AtNCED3 is an important cis-acting element in the induction of the dehydration response. We discuss the possible transcriptional regulatory system of dehydration-responsive AtNCED3 expression, and how this may control the level of ABA under water-deficit conditions. PMID:23604098

  7. THE ROLE OF 4-HYDROXYPHENYLPYRUVATE DIOXYGENASE IN ENHANCEMENT OF SOLID-PHASE ELECTRON TRANSFER BY SHEWANELLA ONEIDENSIS MR-1

    Energy Technology Data Exchange (ETDEWEB)

    Turick, C; Amy Ekechukwu, A

    2007-06-01

    While mechanistic details of dissimilatory metal reduction are far from being understood, it is postulated that the electron transfer to solid metal oxides is mediated by outer membrane-associated c-type cytochromes and redox active electron shuttling compounds. This study focuses on the production of homogensitate in Shewanella oneidensis MR-1, an intermediate of tyrosine degradation pathway, which is a precursor of a redox cycling metabolite, pyomelanin. In this study, we determined that two enzymes involved in this pathway, 4-hydroxyphenylpyruvate dioxygenase (4HPPD) and homogentisate 1,2-dioxygenase are responsible for homogentisate production and oxidation, respectively. Inhibition of 4-HPPD activity with the specific inhibitor sulcotrione (2-(2-chloro-4-methane sulfonylbenzoyl)-1,3-cyclohexanedione), and deletion of melA, a gene encoding 4-HPPD, resulted in no pyomelanin production by S. oneidensis MR-1. Conversely, deletion of hmgA which encodes the putative homogentisate 1,2-dioxygenase, resulted in pyomelanin overproduction. The efficiency and rates, with which MR-1 reduces hydrous ferric oxide, were directly linked to the ability of mutant strains to produce pyomelanin. Electrochemical studies with whole cells demonstrated that pyomelanin substantially increases the formal potential (E{sup o}{prime}) of S. oneidensis MR-1. Based on this work, environmental production of pyomelanin likely contributes to an increased solid-phase metal reduction capacity in Shewanella oneidensis.

  8. Molecular mechanism of strict substrate specificity of an extradiol dioxygenase, DesB, derived from Sphingobium sp. SYK-6.

    Directory of Open Access Journals (Sweden)

    Keisuke Sugimoto

    Full Text Available DesB, which is derived from Sphingobium sp. SYK-6, is a type II extradiol dioxygenase that catalyzes a ring opening reaction of gallate. While typical extradiol dioxygenases show broad substrate specificity, DesB has strict substrate specificity for gallate. The substrate specificity of DesB seems to be required for the efficient growth of S. sp. SYK-6 using lignin-derived aromatic compounds. Since direct coordination of hydroxyl groups of the substrate to the non-heme iron in the active site is a critical step for the catalytic reaction of the extradiol dioxygenases, the mechanism of the substrate recognition and coordination of DesB was analyzed by biochemical and crystallographic methods. Our study demonstrated that the direct coordination between the non-heme iron and hydroxyl groups of the substrate requires a large shift of the Fe (II ion in the active site. Mutational analysis revealed that His124 and His192 in the active site are essential to the catalytic reaction of DesB. His124, which interacts with OH (4 of the bound gallate, seems to contribute to proper positioning of the substrate in the active site. His192, which is located close to OH (3 of the gallate, is likely to serve as the catalytic base. Glu377' interacts with OH (5 of the gallate and seems to play a critical role in the substrate specificity. Our biochemical and structural study showed the substrate recognition and catalytic mechanisms of DesB.

  9. Characterization of arene di-oxygenases involved in polycyclic aromatic hydrocarbons biodegradation in Mycobacterium sp. 6PY1; Caracterisation d'arene dioxygenases impliquees dans la biodegradation des hydrocarbures aromatiques polycycliques chez Mycobacterium sp. 6PY1

    Energy Technology Data Exchange (ETDEWEB)

    Kuony, S.

    2005-06-15

    This thesis deals with the bacterial biodegradation of pollutants called polycyclic aromatic hydrocarbons (PAHs). The bacterium Mycobacterium sp. 6PY1 was isolated from a polluted soil for its ability to use pyrene, a 4-ring PAH, as sole source of carbon and energy. To learn about the pyrene metabolic pathway, the identification of the enzymes involved in this process has been undertaken using a proteomic approach. This approach revealed the occurrence of two ring-hydroxylating di-oxygenases in strain 6PY1, which could catalyze the initial attack of pyrene. The goal of this study was to clone the genes encoding the di-oxygenases identified in Mycobacterium sp. 6PY1, over-express these genes in an heterologous system in order to facilitate the purification of the corresponding enzymes, and determine the biochemical and catalytic properties of these enzymes. The pdoA1B1 genes encoding the terminal component of a di-oxygenase were cloned and over-expressed in Escherichia coli. The catalytic properties of this enzyme, called Pdo1, were determined in vivo by measuring the oxidation products of 2- to 4-ring PAHs by gas chromatography coupled to mass spectrometry (GC-MS). Analysis of the selectivity of the enzyme, as determined using GC-MS, showed that Pdo1 preferentially oxidized 3- or 4-ring PAHs, including phenanthrene and pyrene, but was inactive on di-aromatic compounds such as naphthalene and biphenyl. Pdo1 was unstable and was therefore purified in inactive form. The genes encoding a second di-oxygenase component were found in a locus containing two other catabolic genes. The pdoA2B2 genes encoded an enzyme called Pdo2 showing a narrow specificity towards 2- to 3-ring PAHs, and a high preference for phenanthrene. Pdo2 is an a3{beta}3 hexamer, containing [2Fe-2S] Rieske clusters which confer it a characteristic absorbance spectrum. A third set of genes possibly encoding another di-oxygenase was discovered in the genome of Mycobacterium sp. 6PY1. This set is closely

  10. A Mathematical Model of Tryptophan Metabolism via the Kynurenine Pathway Provides Insights into the Effects of Vitamin B-6 Deficiency, Tryptophan Loading, and Induction of Tryptophan 2,3-Dioxygenase on Tryptophan Metabolites123

    Science.gov (United States)

    Rios-Avila, Luisa; Nijhout, H. Frederik; Reed, Michael C.; Sitren, Harry S.; Gregory, Jesse F.

    2013-01-01

    Vitamin B-6 deficiency is associated with impaired tryptophan metabolism because of the coenzyme role of pyridoxal 5′-phosphate (PLP) for kynureninase and kynurenine aminotransferase. To investigate the underlying mechanism, we developed a mathematical model of tryptophan metabolism via the kynurenine pathway. The model includes mammalian data on enzyme kinetics and tryptophan transport from the intestinal lumen to liver, muscle, and brain. Regulatory mechanisms and inhibition of relevant enzymes were included. We simulated the effects of graded reduction in cellular PLP concentration, tryptophan loads and induction of tryptophan 2,3-dioxygenase (TDO) on metabolite profiles and urinary excretion. The model predictions matched experimental data and provided clarification of the response of metabolites in various extents of vitamin B-6 deficiency. We found that moderate deficiency yielded increased 3-hydroxykynurenine and a decrease in kynurenic acid and anthranilic acid. More severe deficiency also yielded an increase in kynurenine and xanthurenic acid and more pronounced effects on the other metabolites. Tryptophan load simulations with and without vitamin B-6 deficiency showed altered metabolite concentrations consistent with published data. Induction of TDO caused an increase in all metabolites, and TDO induction together with a simulated vitamin B-6 deficiency, as has been reported in oral contraceptive users, yielded increases in kynurenine, 3-hydroxykynurenine, and xanthurenic acid and decreases in kynurenic acid and anthranilic acid. These results show that the model successfully simulated tryptophan metabolism via the kynurenine pathway and can be used to complement experimental investigations. PMID:23902960

  11. Synthesis and Herbicidal Activity of Triketone-Quinoline Hybrids as Novel 4-Hydroxyphenylpyruvate Dioxygenase Inhibitors.

    Science.gov (United States)

    Wang, Da-Wei; Lin, Hong-Yan; Cao, Run-Jie; Chen, Tao; Wu, Feng-Xu; Hao, Ge-Fei; Chen, Qiong; Yang, Wen-Chao; Yang, Guang-Fu

    2015-06-17

    4-Hydroxyphenylpyruvate dioxygenase (EC 1.13.11.27, HPPD) is one of the most important targets for herbicide discovery. In the search for new HPPD inhibitors with novel scaffolds, triketone-quinoline hybrids were designed and subsequently optimized on the basis of the structure-activity relationship (SAR) studies. Most of the synthesized compounds displayed potent inhibition of Arabidopsis thaliana HPPD (AtHPPD), and some of them exhibited broad-spectrum and promising herbicidal activity at the rate of 150 g ai/ha by postemergence application. Most promisingly, compound III-l, 3-hydroxy-2-(2-methoxy-7-(methylthio)quinoline-3-carbonyl)cyclohex-2-enone (Ki = 0.009 μM, AtHPPD), had broader spectrum of weed control than mesotrione. Furthermore, compound III-l was much safer to maize at the rate of 150 g ai/ha than mesotrione, demonstrating its great potential as herbicide for weed control in maize fields. Therefore, triketone-quinoline hybrids may serve as new lead structures for novel herbicide discovery.

  12. Expression Profile of Carotenoid Cleavage Dioxygenase Genes in Summer Squash (Cucurbita pepo L.).

    Science.gov (United States)

    González-Verdejo, Clara I; Obrero, Ángeles; Román, Belén; Gómez, Pedro

    2015-06-01

    Carotenoids are important dietary components that can be found in vegetable crops. The accumulation of these compounds in fruit and vegetables is altered by the activity of carotenoid cleavage dioxygenases (CCDs) enzymes that produce their degradation. The aim of this work was to study the possible implication of CCD genes in preventing carotenoid storage in the horticultural crop summer squash (Cucurbita pepo L.). The relationship between the presence of these compounds and gene expression for CCDs was studied in three varieties showing different peel and flesh colour. Expression analysis for the CCD genes CpNCED1, CpNCED2, CpNCED3, CpNCED9, CpCCD1, CpCCD4a, CpCCD4b and CpCCD8 was carried out on different organs and at several fruit developmental stages. The results showed that the CpCCD4a and CpCCD4b genes were highly expressed in the variety with lowest carotenoid content suggesting a putative role in carotenoid accumulation pattern in summer squash fruit.

  13. Zinc protoporphyrin IX stimulates tumor immunity by disrupting the immunosuppressive enzyme indoleamine 2,3-dioxygenase.

    Science.gov (United States)

    Metz, Richard; Duhadaway, James B; Rust, Sonja; Munn, David H; Muller, Alexander J; Mautino, Mario; Prendergast, George C

    2010-06-01

    The tryptophan catabolic enzyme indoleamine 2,3-dioxygenase (IDO) has emerged as an important driver of immune escape in a growing number of cancers and cancer-associated chronic infections. In this study, we define novel immunotherapeutic applications for the heme precursor compound zinc protoporphyrin IX (ZnPP) based on our discovery that it is a potent small-molecule inhibitor of IDO. Inhibitory activity was determined using in vitro and in-cell enzyme assays as well as a novel in vivo pharmacodynamic system. An irreversible mechanism of inhibition was documented, consistent with competition for heme binding in newly synthesized cellular protein. siRNA methodology and an IDO-deficient mouse strain were used to verify the specificity of ZnPP as an IDO inhibitor. In a preclinical model of melanoma, ZnPP displayed antitumor properties that relied on T-cell function and IDO integrity. ZnPP also phenocopied the known antitumor properties of IDO inhibitors in preclinical models of skin and breast carcinoma. Our results suggest clinical evaluation of ZnPP as an adjuvant immunochemotherapy in chronic infections and cancers in which there is emerging recognition of a pathophysiologic role for IDO dysregulation.

  14. Lignans from Carthamus tinctorius suppress tryptophan breakdown via indoleamine 2,3-dioxygenase

    Science.gov (United States)

    Kuehnl, Susanne; Schroecksnadel, Sebastian; Temml, Veronika; Gostner, Johanna M.; Schennach, Harald; Schuster, Daniela; Schwaiger, Stefan; Rollinger, Judith M.; Fuchs, Dietmar; Stuppner, Hermann

    2013-01-01

    Seed extracts of Carthamus tinctorius L. (Asteraceae), safflower, have been traditionally used to treat coronary disease, thrombotic disorders, and menstrual problems but also against cancer and depression. A possible effect of C. tinctorius compounds on tryptophan-degrading activity of enzyme indoleamine 2,3-dioxygenase (IDO) could explain many of its activities. To test for an effect of C. tinctorius extracts and isolated compounds on cytokine-induced IDO activity in immunocompetent cells in vitro methanol and ethylacetate seed extracts were prepared from cold pressed seed cakes of C. tinctorius and three lignan derivatives, trachelogenin, arctigenin and matairesinol were isolated. The influence on tryptophan breakdown was investigated in peripheral blood mononuclear cells (PBMCs). Effects were compared to neopterin production in the same cellular assay. Both seed extracts suppressed tryptophan breakdown in stimulated PBMC. The three structurally closely related isolates exerted differing suppressive activity on PBMC: arctigenin (IC50 26.5 μM) and trachelogenin (IC50 of 57.4 μM) showed higher activity than matairesinol (IC50 >200 μM) to inhibit tryptophan breakdown. Effects on neopterin production were similar albeit generally less strong. Data show an immunosuppressive property of compounds which slows down IDO activity. The in vitro results support the view that some of the anti-inflammatory, anti-cancer and antidepressant properties of C. tinctorius lignans might relate to their suppressive influence on tryptophan breakdown. PMID:23867649

  15. Structural insights into substrate and inhibitor binding sites in human indoleamine 2,3-dioxygenase 1

    Energy Technology Data Exchange (ETDEWEB)

    Lewis-Ballester, Ariel; Pham, Khoa N.; Batabyal, Dipanwita; Karkashon, Shay; Bonanno, Jeffrey B.; Poulos, Thomas L.; Yeh, Syun-Ru (Einstein); (UCI)

    2017-11-22

    Human indoleamine 2,3-dioxygenase 1 (hIDO1) is an attractive cancer immunotherapeutic target owing to its role in promoting tumoral immune escape. However, drug development has been hindered by limited structural information. Here, we report the crystal structures of hIDO1 in complex with its substrate, Trp, an inhibitor, epacadostat, and/or an effector, indole ethanol (IDE). The data reveal structural features of the active site (Sa) critical for substrate activation; in addition, they disclose a new inhibitor-binding mode and a distinct small molecule binding site (Si). Structure-guided mutation of a critical residue, F270, to glycine perturbs the Si site, allowing structural determination of an inhibitory complex, where both the Sa and Si sites are occupied by Trp. The Si site offers a novel target site for allosteric inhibitors and a molecular explanation for the previously baffling substrate-inhibition behavior of the enzyme. Taken together, the data open exciting new avenues for structure-based drug design.

  16. Cysteine dioxygenase type 1 promotes adipogenesis via interaction with peroxisome proliferator-activated receptor gamma

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Peng; Chen, Yi; Ji, Ning; Lin, Yunfeng; Yuan, Quan; Ye, Ling; Chen, Qianming, E-mail: qmchen@scu.edu.cn

    2015-02-27

    Mammalian cysteine dioxygenase type 1 (CDO1) is an essential enzyme for taurine biosynthesis and the biodegradation of toxic cysteine. As previously suggested, Cdo1 may be a marker of liposarcoma progression and adipogenic differentiation, but the role of Cdo1 in adipogenesis has yet been reported. In this study, we found that the expression of Cdo1 is dramatically elevated during adipogenic differentiation of 3T3-L1 pre-adipocytes and mouse bone marrow-derived mesenchymal stem cells (mBMSCs). Conversely, knockdown of Cdo1 inhibited expression of adipogenic specific genes and lipid droplet formation in 3T3-L1 cells and mBMSCs. Mechanistically, we found Cdo1 interacted with Pparγ in response to adipogenic stimulus. Further, depletion of Cdo1 reduced the recruitment of Pparγ to the promoters of C/EBPα and Fabp4. Collectively, our finding indicates that Cdo1 may be a co-activator of Pparγ in adipogenesis, and may contribute to the development of disease associated with excessive adipose tissue. - Highlights: • Cdo1expression is highly up-regulated during adipogenic differentiation of 3T3-L1 and mBMSCs. • Depletion of Cdo1 inhibited expression of adipogenic specific genes and lipid droplet formation. • Cdo1interacts with Pparγ during adipogenesis. • Knockdown of Cdo1 inhibited Pparγ binding to the promoters of C/EBPα and Fabp4.

  17. Detection of benzene, toluene, ethyl benzene, and xylenes (BTEX) using toluene dioxygenase-peroxidase coupling reactions.

    Science.gov (United States)

    Xu, Zhaohui; Mulchandani, Ashok; Chen, Wilfred

    2003-01-01

    We have developed a simple, whole-cell bioassay for the detection of bioavailable benzene, toluene, ethyl benzene, and xylenes (BTEX) and similar compounds. A genetically engineered E. coli strain expressing toluene dioxygenase (TDO) and toluene dihydrodiol dehydrogenase (TodD) was constructed, enabling the conversion of BTEX into their respective catechols, which were quickly converted into colored products by a horseradish peroxidase (HRP)-coupled reaction. The intensity of the color formation was correlated to concentrations of the BTEX compounds. Under the optimized conditions, a detection limit (defined as three times the standard deviation of the response obtained from the blank) of 10, 10, 20, and 50 microM was observed for benzene, toluene, ethyl benzene, and xylene, respectively. The bioassay was selective toward BTEX-related compounds with no interference observed with commonly used pesticides, herbicides, and organic solvent. The bioassay was very stable with little change in response over a 10-week period. The excellent stability suggests that the reported bioassay may be suitable for field monitoring of BTEX to identify and track contaminated water and follow the bioremediation progress.

  18. On the substrate- and stereospecificity of the plant carotenoid cleavage dioxygenase 7

    KAUST Repository

    Bruno, Mark

    2014-05-01

    Strigolactones are phytohormones synthesized from carotenoids via a stereospecific pathway involving the carotenoid cleavage dioxygenases 7 (CCD7) and 8. CCD7 cleaves 9-cis-β-carotene to form a supposedly 9-cis-configured β-apo-10′-carotenal. CCD8 converts this intermediate through a combination of yet undetermined reactions into the strigolactone-like compound carlactone. Here, we investigated the substrate and stereo-specificity of the Arabidopsis and pea CCD7 and determined the stereo-configuration of the β-apo-10′-carotenal intermediate by using Nuclear Magnetic Resonance Spectroscopy. Our data unequivocally demonstrate the 9-cis-configuration of the intermediate. Both CCD7s cleave different 9-cis-carotenoids, yielding hydroxylated 9-cis-apo-10′-carotenals that may lead to hydroxylated carlactones, but show highest affinity for 9-cis-β-carotene. © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  19. Indoleamine 2,3-dioxygenase expression in patients with allergic rhinitis: a case-control study

    Directory of Open Access Journals (Sweden)

    Luukkainen Annika

    2011-12-01

    Full Text Available Abstract Background Indoleamine 2,3-dioxygenase (IDO is a tryptophan catalyzing enzyme. It has been suggested that it has a role in lower airway allergic inflammations, but its role in allergic rhinitis has not been investigated. Objective Our aim was to evaluate the expression of IDO in the nasal mucosa of allergic rhinitis patients allergic to birch pollen during peak exposure to birch pollen allergen and compare it to non-atopic patients. Methods IDO expression was immunohistochemically evaluated from nasal specimens obtained in- and off-season from otherwise healthy non-smoking volunteers both allergic to birch pollen (having mild or moderate allergic rhinoconjunctivitis and non-allergic controls. Results: The IDO expression levels were low in healthy controls and remained low also in patients allergic to birch pollen. There were no differences in the expression of IDO in- and off-season in either healthy or allergic subjects. Conclusions There is a controversy in the role of IDO in upper and lower airways during allergic airway disease. It seems that IDO is associated to allergic inflammations of the lower airways, but does not have a local role in the nasal cavity at least in mild or moderate forms of allergic rhinitis.

  20. Isolation and Functional Characterization of Carotenoid Cleavage Dioxygenase-1 from Laurus nobilis L. (Bay Laurel) Fruits.

    Science.gov (United States)

    Yahyaa, Mosaab; Berim, Anna; Isaacson, Tal; Marzouk, Sally; Bar, Einat; Davidovich-Rikanati, Rachel; Lewinsohn, Efraim; Ibdah, Mwafaq

    2015-09-23

    Bay laurel (Laurus nobilis L.) is an agriculturally important tree used in food, drugs, and the cosmetics industry. Many of the health beneficial properties of bay laurel are due to volatile terpene metabolites that they contain, including various norisoprenoids. Despite their importance, little is known about the norisoprenoid biosynthesis in Laurus nobilis fruits. We found that the volatile norisoprenoids 6-methyl-5-hepten-2-one, pseudoionone, and β-ionone accumulated in Laurus nobilis fruits in a pattern reflecting their carotenoid content. A full-length cDNA encoding a potential carotenoid cleavage dioxygenase (LnCCD1) was isolated. The LnCCD1 gene was overexpressed in Escherichia coli, and recombinant protein was assayed for its cleavage activity with an array of carotenoid substrates. The LnCCD1 protein was able to cleave a variety of carotenoids at the 9,10 (9',10') and 5,6 (5',6') positions to produce 6-methyl-5-hepten-2-one, pseudoionone, β-ionone, and α-ionone. Our results suggest a role for LnCCD1 in Laurus nobilis fruit flavor biosynthesis.

  1. Indoleamine 2,3 Dioxygenase (IDO Expression and Activity in Relapsing-Remitting Multiple Sclerosis.

    Directory of Open Access Journals (Sweden)

    Roberta Mancuso

    Full Text Available Interferon gamma (IFN-γ production induces the transcription of indoleamine 2,3 dioxygenase (IDO resulting in the reduction of T-cell activation and proliferation through the depletion of tryptophan and the elicitation of Treg lymphocytes. IDO was shown to be involved in the pathogenesis of autoimmune diseases; we investigated whether changes in IDO gene expression and activity could be indicative of onset of relapse in multiple sclerosis (MS patients.IDO and interferon-γ (IFN-γ gene expression, serum IDO activity (Kynurenine/Tryptophan ratio and serum neopterin concentration--a protein released by macrophages upon IFN-γ stimulation--were measured in 51 individuals: 36 relapsing remitting (RR-MS patients (21 in acute phase--AMS, 15 in stable phase--SMS and 15 healthy controls (HC. PBMCs samples in AMS patients were collected before (BT-AMS and during glucocorticoids-based therapy (DT-AMS.IDO expression was increased and IFN-γ was decreased (p<0.001 in BT-AMS compared to SMS patients. Glucocorticoids-induced disease remission resulted in a significant reduction of IDO and IFN-γ gene expression, IDO catalytic activity (p<0.001. Serum neopterin concentration followed the same trend as IDO expression and activity.Measurement of IDO gene expression and activity in blood could be a useful marker to monitor the clinical course of RR-MS. Therapeutic interventions modulating IDO activity may be beneficial in MS.

  2. Indoleamine 2,3-dioxygenase (IDO): the antagonist of type I interferon-driven skin inflammation?

    Science.gov (United States)

    Scheler, Marina; Wenzel, Joerg; Tüting, Thomas; Takikawa, Osamu; Bieber, Thomas; von Bubnoff, Dagmar

    2007-12-01

    Recent studies have provided evidence that a type I interferon (IFN)-driven immune response might play an important role in the pathogenesis of lichen planus (LP), an inflammatory disorder of the skin of unclear etiology. Plasmacytoid dendritic cells in affected skin from LP have been proposed to produce IFN-alpha/beta locally, which leads to the expression of IFN-inducible chemokines such as IP10/CXCL10 in the epidermis. This chemokine recruits chemokine receptor CXCR3-expressing T-lymphocytes into the skin via CXCR3/IP10 interactions. Indoleamine 2,3-dioxygenase (IDO), which degrades tryptophan and suppresses T-cell proliferation, is induced by IFNs and other inflammatory cytokines. We show that type I IFN-mediated skin disorders, such as LP, strongly express IDO in lesional skin. This expression closely correlates to the expression of the highly specific type I IFN marker MxA. We further demonstrate that the IDO+ cells in LP are large myeloid CD11c+S100+CD68(-) dendritic cells. Accordingly, CD11c+ antigen-presenting cells significantly up-regulate IDO gene expression and intracellular IDO protein expression after stimulation with IFN-alpha in vitro. These findings reveal that both proinflammatory and counterregulatory mechanisms are operative in cutaneous lesions of LP. We propose that the balance of these mechanisms may be involved in the pathogenesis of this disorder.

  3. The immune system strikes back: cellular immune responses against indoleamine 2,3-dioxygenase.

    Directory of Open Access Journals (Sweden)

    Rikke Baek Sørensen

    2009-09-01

    Full Text Available The enzyme indoleamine 2,3-dioxygenase (IDO exerts an well established immunosuppressive function in cancer. IDO is expressed within the tumor itself as well as in antigen-presenting cells in tumor-draining lymph nodes, where it promotes the establishment of peripheral immune tolerance to tumor antigens. In the present study, we tested the notion whether IDO itself may be subject to immune responses.The presence of naturally occurring IDO-specific CD8 T cells in cancer patients was determined by MHC/peptide stainings as well as ELISPOT. Antigen specific cytotoxic T lymphocytes (CTL from the peripheral blood of cancer patients were cloned and expanded. The functional capacity of the established CTL clones was examined by chrome release assays. The study unveiled spontaneous cytotoxic T-cell reactivity against IDO in peripheral blood as well as in the tumor microenvironment of different cancer patients. We demonstrate that these IDO reactive T cells are indeed peptide specific, cytotoxic effector cells. Hence, IDO reactive T cells are able to recognize and kill tumor cells including directly isolated AML blasts as well as IDO-expressing dendritic cells, i.e. one of the major immune suppressive cell populations.IDO may serve as an important and widely applicable target for anti-cancer immunotherapeutic strategies. Furthermore, as emerging evidence suggests that IDO constitutes a significant counter-regulatory mechanism induced by pro-inflammatory signals, IDO-based immunotherapy holds the promise to boost anti-cancer immunotherapy in general.

  4. 1,2,3-Triazoles as inhibitors of indoleamine 2,3-dioxygenase 2 (IDO2).

    Science.gov (United States)

    Röhrig, Ute F; Majjigapu, Somi Reddy; Caldelari, Daniela; Dilek, Nahzli; Reichenbach, Patrick; Ascencao, Kelly; Irving, Melita; Coukos, George; Vogel, Pierre; Zoete, Vincent; Michielin, Olivier

    2016-09-01

    Indoleamine 2,3-dioxygenase 2 (IDO2) is a potential therapeutic target for the treatment of diseases that involve immune escape such as cancer. In contrast to IDO1, only a very limited number of inhibitors have been described for IDO2 due to inherent difficulties in expressing and purifying a functionally active, soluble form of the enzyme. Starting from our previously discovered highly efficient 4-aryl-1,2,3-triazole IDO1 inhibitor scaffold, we used computational structure-based methods to design inhibitors of IDO2 which we then tested in cellular assays. Our approach yielded low molecular weight inhibitors of IDO2, the most active displaying an IC50 value of 51μM for mIDO2, and twofold selectivity over hIDO1. These compounds could be useful as molecular probes to investigate the biological role of IDO2, and could inspire the design of new IDO2 inhibitors. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Functional expression of a valencene dioxygenase from Pleurotus sapidus in E. coli.

    Science.gov (United States)

    Zelena, Kateryna; Krings, Ulrich; Berger, Ralf G

    2012-03-01

    Valencene dioxygenase (ValOx) from the edible basidiomycete Pleurotus sapidus converted the sesquiterpene (+)-valencene to the valuable grapefruit flavour (+)-nootkatone and to nootkatols through intermediate hydroperoxides. Expression of the enzyme was carried out in the cytosol and periplasm of Escherichia coli. The heterologous production led to high yields of inclusion bodies. The poor yield of soluble recombinant protein was improved by various strategies including cold shock expression, chaperone co-expression, and employment of mutant E. coli strains. Up to 60 mg of the biologically active, soluble ValOx was produced by cold shock under control of the cspA promoter at 8 °C in the BL21(DE3)Star strain and co-expression of the E. coli trigger factor. The recombinant enzyme, purified using the N-terminal His tag, showed the catalytic properties of the wild-type enzyme, as was confirmed by the LC-MS analysis of hydroperoxide intermediates and GC-MS analysis of the volatile products. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. Knockout of the murine cysteine dioxygenase gene results in severe impairment in ability to synthesize taurine and an increased catabolism of cysteine to hydrogen sulfide

    Science.gov (United States)

    Ueki, Iori; Roman, Heather B.; Valli, Alessandro; Fieselmann, Krista; Lam, Jimmy; Peters, Rachel; Hirschberger, Lawrence L.

    2011-01-01

    Cysteine homeostasis is dependent on the regulation of cysteine dioxygenase (CDO) in response to changes in sulfur amino acid intake. CDO oxidizes cysteine to cysteinesulfinate, which is further metabolized to either taurine or to pyruvate plus sulfate. To gain insight into the physiological function of CDO and the consequence of a loss of CDO activity, mice carrying a null CDO allele (CDO+/− mice) were crossed to generate CDO−/−, CDO+/−, and CDO+/+ mice. CDO−/− mice exhibited postnatal mortality, growth deficit, and connective tissue pathology. CDO−/− mice had extremely low taurine levels and somewhat elevated cysteine levels, consistent with the lack of flux through CDO-dependent catabolic pathways. However, plasma sulfate levels were slightly higher in CDO−/− mice than in CDO+/− or CDO+/+ mice, and tissue levels of acid-labile sulfide were elevated, indicating an increase in cysteine catabolism by cysteine desulfhydration pathways. Null mice had lower hepatic cytochrome c oxidase levels, suggesting impaired electron transport capacity. Supplementation of mice with taurine improved survival of male pups but otherwise had little effect on the phenotype of the CDO−/− mice. H2S has been identified as an important gaseous signaling molecule as well as a toxicant, and pathology may be due to dysregulation of H2S production. Control of cysteine levels by regulation of CDO may be necessary to maintain low H2S/sulfane sulfur levels and facilitate the use of H2S as a signaling molecule. PMID:21693692

  7. Remarkable ability of Pandoraea pnomenusa B356 biphenyl dioxygenase to metabolize simple flavonoids.

    Science.gov (United States)

    Pham, Thi Thanh My; Tu, Youbin; Sylvestre, Michel

    2012-05-01

    Many investigations have provided evidence that plant secondary metabolites, especially flavonoids, may serve as signal molecules to trigger the abilities of bacteria to degrade chlorobiphenyls in soil. However, the bases for this interaction are largely unknown. In this work, we found that BphAE(B356), the biphenyl/chlorobiphenyl dioxygenase from Pandoraea pnomenusa B356, is significantly better fitted to metabolize flavone, isoflavone, and flavanone than BphAE(LB400) from Burkholderia xenovorans LB400. Unlike those of BphAE(LB400), the kinetic parameters of BphAE(B356) toward these flavonoids were in the same range as for biphenyl. In addition, remarkably, the biphenyl catabolic pathway of strain B356 was strongly induced by isoflavone, whereas none of the three flavonoids induced the catabolic pathway of strain LB400. Docking experiments that replaced biphenyl in the biphenyl-bound form of the enzymes with flavone, isoflavone, or flavanone showed that the superior ability of BphAE(B356) over BphAE(LB400) is principally attributable to the replacement of Phe336 of BphAE(LB400) by Ile334 and of Thr335 of BphAE(LB400) by Gly333 of BphAE(B356). However, biochemical and structural comparison of BphAE(B356) with BphAE(p4), a mutant of BphAE(LB400) which was obtained in a previous work by the double substitution Phe336Met Thr335Ala of BphAE(LB400), provided evidence that other residues or structural features of BphAE(B356) whose precise identification the docking experiment did not allow are also responsible for the superior catalytic abilities of BphAE(B356). Together, these data provide supporting evidence that the biphenyl catabolic pathways have evolved divergently among proteobacteria, where some of them may serve ecological functions related to the metabolism of plant secondary metabolites in soil.

  8. Indoleamine 2,3-dioxygenase protects corneal endothelial cells from UV mediated damage.

    Science.gov (United States)

    Serbecic, Nermin; Beutelspacher, Sven Christoph

    2006-03-01

    Indoleamine-2,3-dioxygenase (IDO) is an intracellular enzyme present in dendritic cells and macrophages. It is a known modulator of T-cell response and contributes to the UV protection of the lens. There yet is no information on IDO activity in the corneal endothelium, protecting the endothelial cells from light mediated damage. We exposed murine corneal endothelial cells (MCEC) with different doses of UV-B light 280-320 nm, probed for IDO mRNA (real-time PCR) and assessed apoptosis rate (flow cytometry) and caspase-3-activity in the cells. The metabolites of the IDO catalysed reaction, l-kynurenine, was also measured. Malondialdehyde was detected for quantification of UV-B-induced oxidative stress. To investigate specificity, IDO effects were blocked by 1-methyl-tryptophan. The effects of IDO overexpression in the MCEC were assessed by transfection of an expression vector. MCEC consistently express IDO at low levels. Exposure to UV-B light led to a dose-responding upregulation of IDO; IDO was found competent converting l-tryptophan into l-kynurenine. Irradiation led to increased apoptosis and caspase-3-activity of MCEC. Supplementation of l-kynurenine or overexpression of IDO in the MCEC could reduce apoptosis significantly following UV-B irradiation. Inhibition of IDO by 1-MT was potent to reverse this effect. IDO and its metabolite l-kynurenine can protect corneal endothelial cells from UV-B-induced oxidative stress and apoptosis. It may be an active protection mechanism against corneal endothelial damage.

  9. Indoleamine 2,3-dioxygenase and regulatory T cells in acute myeloid leukemia.

    Science.gov (United States)

    Mansour, Iman; Zayed, Rania A; Said, Fadwa; Latif, Lamyaa Abdel

    2016-09-01

    The microenvironment of acute myeloid leukemia (AML) is suppressive for immune cells. Regulatory T cells (Tregs) have been recognized to play a role in helping leukemic cells to evade immunesurveillance. The mesenchymal stem cells (MSCs) are essential contributors in immunomodulation of the microenvironment as they can promote differentiation of Tregs via the indoleamine 2,3-dioxygenase (IDO) pathway. The aim of the present work was to evaluate the expression of IDO in bone marrow derived MSCs and to study its correlation to percentage of Tregs. Thirty-seven adult bone marrow samples were cultured in appropriate culture medium to isolate MSCs. Successful harvest of MSCs was determined by plastic adherence, morphology, and positive expression of CD271 and CD105; negative expression of CD34 and CD45 using flowcytometry. MSCs were examined for IDO expression by immunocytochemistry using anti-IDO monoclonal antibody. CD4+ CD25+ cells (Tregs) were measured in bone marrow samples by flowcytometry. MSCs were successfully isolated from 20 of the 37 bone marrow samples cultured. MSCs showed higher expression of IDO and Tregs percentage was higher in AML patients compared to control subjects (P = 0.002 and P < 0.001, respectively). A positive correlation was found between IDO expression and Tregs percentage (P value = 0.012, r = 0.5). In this study, we revealed an association between high IDO expression in MSCs and elevated levels of Tregs which could have an important role in the pathogenesis of AML, providing immunosuppressive microenvironment.

  10. Glial and tissue-specific regulation of Kynurenine Pathway dioxygenases by acute stress of mice

    Directory of Open Access Journals (Sweden)

    Carlos R. Dostal

    2017-12-01

    Full Text Available Stressors activate the hypothalamic-pituitary-adrenal (HPA axis and immune system eliciting changes in cognitive function, mood and anxiety. An important link between stress and altered behavior is stimulation of the Kynurenine Pathway which generates neuroactive and immunomodulatory kynurenines. Tryptophan entry into this pathway is controlled by rate-limiting indoleamine/tryptophan 2,3-dioxygenases (DOs: Ido1, Ido2, Tdo2. Although implicated as mediating changes in behavior, detecting stress-induced DO expression has proven inconsistent. Thus, C57BL/6J mice were used to characterize DO expression in brain-regions, astrocytes and microglia to characterize restraint-stress-induced DO expression. Stress increased kynurenine in brain and plasma, demonstrating increased DO activity. Of three Ido1 transcripts, only Ido1-v1 expression was increased by stress and within astrocytes, not microglia, indicating transcript- and glial-specificity. Stress increased Ido1-v1 only in frontal cortex and hypothalamus, indicating brain-region specificity. Of eight Ido2 transcripts, Ido2-v3 expression was increased by stress, again only within astrocytes. Likewise, stress increased Tdo2-FL expression in astrocytes, not microglia. Interestingly, Ido2 and Tdo2 transcripts were not correspondingly induced in Ido1-knockout (Ido1KO mice, suggesting that Ido1 is necessary for the central DO response to acute stress. Unlike acute inflammatory models resulting in DO induction within microglia, only astrocyte DO expression was increased by acute restraint-stress, defining their unique role during stress-dependent activation of the Kynurenine Pathway. Keywords: Stress, Ido, Tdo, Kynurenine, Astrocyte, Liver

  11. Evolutionarily distinct carotenoid cleavage dioxygenases are responsible for crocetin production in Buddleja davidii.

    Science.gov (United States)

    Ahrazem, Oussama; Diretto, Gianfranco; Argandoña, Javier; Rubio-Moraga, Ángela; Julve, José Manuel; Orzáez, Diego; Granell, Antonio; Gómez-Gómez, Lourdes

    2017-07-20

    Crocetin, one of the few colored apocarotenoids known in nature, is present in flowers and fruits and has long been used medicinally and as a colorant. Saffron is the main source of crocetin, although a few other plants produce lower amounts of this apocarotenoid. Notably, Buddleja davidii accumulates crocetin in its flowers. Recently, a carotenoid dioxygenase cleavage enzyme, CCD2, has been characterized as responsible for crocetin production in Crocus species. We searched for CCD2 homologues in B. davidii and identified several CCD enzymes from the CCD1 and CCD4 subfamilies. Unexpectedly, two out of the three CCD4 enzymes, namely BdCCD4.1 and BdCCD4.3, showed 7,8;7',8' activity in vitro and in vivo over zeaxanthin. In silico analyses of these enzymes and CCD2 allowed the determination of key residues for this activity. Both BdCCD4 genes are highly expressed during flower development and transcripts levels parallel the accumulation of crocins in the petals. Phylogenetic analysis showed that BdCCD4.2 grouped with almost all the characterized CCD4 enzymes, while BdCCD4.1 and BdCCD4.3 form a new sub-cluster together with CCD4 enzymes from certain Lamiales species. The present study indicates that convergent evolution led to the acquisition of 7,8;7',8' apocarotenoid cleavage activity in two separate CCD enzyme families. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  12. Resonance Raman study on indoleamine 2,3-dioxygenase: Control of reactivity by substrate-binding

    Energy Technology Data Exchange (ETDEWEB)

    Yanagisawa, Sachiko; Hara, Masayuki [Graduate School of Life Science and Picobiology Institute, University of Hyogo, Koto 3-2-1, Kamigori-cho, Ako-gun, Hyogo 678-1297 (Japan); Sugimoto, Hiroshi; Shiro, Yoshitsugu [Biometal Science Laboratory, RIKEN SPring-8 Center, Harima Institute, Koto 1-1-1, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Ogura, Takashi, E-mail: ogura@sci.u-hyogo.ac.jp [Graduate School of Life Science and Picobiology Institute, University of Hyogo, Koto 3-2-1, Kamigori-cho, Ako-gun, Hyogo 678-1297 (Japan)

    2013-06-20

    Highlights: • Indoleamine 2,3-dioygenase has been studied by resonance Raman spectroscopy. • Trp-binding to the enzyme induces high frequency shift of the Fe–His stretching mode. • Increased imidazolate character of histidine promotes the O–O bond cleavage step. • A fine-tuning of the reactivity of the O–O bond cleavage reaction is identified. • The results are consistent with the sequential oxygen-atom-transfer mechanism. - Abstract: Resonance Raman spectra of ligand-bound complexes including the 4-phenylimidazole complex and of free and L-Trp-bound forms of indoleamine 2, 3-dioxygenase in the ferric state were examined. Effects on the vinyl and propionate substituent groups of the heme were detected in a ligand-dependent fashion. The effects of phenyl group of 4-phenylimidazole on the vinyl and propionate Raman bands were evident when compared with the case of imidazole ligand. Substrate binding to the ferrous protein caused an upshift of the iron–histidine stretching mode by 3 cm{sup −1}, indicating an increase in negativity of the imidazole ring, which favors the O–O bond cleavage. The substrate binding event is likely to be communicated from the heme distal side to the iron–histidine bond through heme substituent groups and the hydrogen-bond network which includes water molecules, as identified in an X-ray structure of a 4-phenylimidazole complex. The results provide evidence for fine-tuning of the reactivity of O–O bond cleavage by the oxygenated heme upon binding of L-Trp.

  13. Swapping metals in Fe- and Mn-dependent dioxygenases: Evidence for oxygen activation without a change in metal redox state

    Science.gov (United States)

    Emerson, Joseph P.; Kovaleva, Elena G.; Farquhar, Erik R.; Lipscomb, John D.; Que, Lawrence

    2008-01-01

    Biological O2 activation often occurs after binding to a reduced metal [e.g., M(II)] in an enzyme active site. Subsequent M(II)-to-O2 electron transfer results in a reactive M(III)-superoxo species. For the extradiol aromatic ring-cleaving dioxygenases, we have proposed a different model where an electron is transferred from substrate to O2 via the M(II) center to which they are both bound, thereby obviating the need for an integral change in metal redox state. This model is tested by using homoprotocatechuate 2,3-dioxygenases from Brevibacterium fuscum (Fe-HPCD) and Arthrobacter globiformis (Mn-MndD) that share high sequence identity and very similar structures. Despite these similarities, Fe-HPCD binds Fe(II) whereas Mn-MndD incorporates Mn(II). Methods are described to incorporate the nonphysiological metal into each enzyme (Mn-HPCD and Fe-MndD). The x-ray crystal structure of Mn-HPCD at 1.7 Å is found to be indistinguishable from that of Fe-HPCD, while EPR studies show that the Mn(II) sites of Mn-MndD and Mn-HPCD, and the Fe(II) sites of the NO complexes of Fe-HPCD and Fe-MndD, are very similar. The uniform metal site structures of these enzymes suggest that extradiol dioxygenases cannot differentially compensate for the 0.7-V gap in the redox potentials of free iron and manganese. Nonetheless, all four enzymes exhibit nearly the same KM and Vmax values. These enzymes constitute an unusual pair of metallo-oxygenases that remain fully active after a metal swap, implicating a different way by which metals are used to promote oxygen activation without an integral change in metal redox state. PMID:18492808

  14. Swapping metals in Fe- and Mn-dependent dioxygenases: Evidence for oxygen activation without a change in metal redox state

    Energy Technology Data Exchange (ETDEWEB)

    Emerson, Joseph P.; Kovaleva, Elena G.; Farquhar, Erik R.; Lipscomb, John D.; Oue, Jr., Lawrence (UMM)

    2008-07-21

    Biological O{sub 2} activation often occurs after binding to a reduced metal [e.g., M(II)] in an enzyme active site. Subsequent M(II)-to-O{sub 2} electron transfer results in a reactive M(III)-superoxo species. For the extradiol aromatic ring-cleaving dioxygenases, we have proposed a different model where an electron is transferred from substrate to O{sub 2} via the M(II) center to which they are both bound, thereby obviating the need for an integral change in metal redox state. This model is tested by using homoprotocatechuate 2,3-dioxygenases from Brevibacterium fuscum (Fe-HPCD) and Arthrobacter globiformis (Mn-MndD) that share high sequence identity and very similar structures. Despite these similarities, Fe-HPCD binds Fe(II) whereas Mn-MndD incorporates Mn(II). Methods are described to incorporate the nonphysiological metal into each enzyme (Mn-HPCD and Fe-MndD). The x-ray crystal structure of Mn-HPCD at 1.7 {angstrom} is found to be indistinguishable from that of Fe-HPCD, while EPR studies show that the Mn(II) sites of Mn-MndD and Mn-HPCD, and the Fe(II) sites of the NO complexes of Fe-HPCD and Fe-MndD, are very similar. The uniform metal site structures of these enzymes suggest that extradiol dioxygenases cannot differentially compensate for the 0.7-V gap in the redox potentials of free iron and manganese. Nonetheless, all four enzymes exhibit nearly the same K{sub M} and V{sub max} values. These enzymes constitute an unusual pair of metallo-oxygenases that remain fully active after a metal swap, implicating a different way by which metals are used to promote oxygen activation without an integral change in metal redox state.

  15. Stepwise O-Atom Transfer in Heme-Based Tryptophan Dioxygenase: Role of Substrate Ammonium in Epoxide Ring Opening.

    Science.gov (United States)

    Shin, Inchul; Ambler, Brett R; Wherritt, Daniel; Griffith, Wendell P; Maldonado, Amanda C; Altman, Ryan A; Liu, Aimin

    2018-03-28

    Heme-based tryptophan dioxygenases are established immunosuppressive metalloproteins with significant biomedical interest. Here, we synthesized two mechanistic probes to specifically test if the α-amino group of the substrate directly participates in a critical step of the O atom transfer during catalysis in human tryptophan 2,3-dioxygenase (TDO). Substitution of the nitrogen atom of the substrate to a carbon (probe 1) or oxygen (probe 2) slowed the catalytic step following the first O atom transfer such that transferring the second O atom becomes less likely to occur, although the dioxygenated products were observed with both probes. A monooxygenated product was also produced from probe 2 in a significant quantity. Analysis of this new product by HPLC coupled UV-vis spectroscopy, high-resolution mass spectrometry, 1 H NMR, 13 C NMR, HSQC, HMBC, and infrared (IR) spectroscopies concluded that this monooxygenated product is a furoindoline compound derived from an unstable epoxyindole intermediate. These results prove that small molecules can manipulate the stepwise O atom transfer reaction of TDO and provide a showcase for a tunable mechanism by synthetic compounds. The product analysis results corroborate the presence of a substrate-based epoxyindole intermediate during catalysis and provide the first substantial experimental evidence for the involvement of the substrate α-amino group in the epoxide ring-opening step during catalysis. This combined synthetic, biochemical, and biophysical study establishes the catalytic role of the α-amino group of the substrate during the O atom transfer reactions and thus represents a substantial advance to the mechanistic comprehension of the heme-based tryptophan dioxygenases.

  16. Zinc protoporphyrin-IX stimulates tumor immunity by disrupting the immunosuppressive enzyme indoleamine 2,3-dioxygenase

    OpenAIRE

    Metz, Richard; DuHadaway, James B.; Rust, Sonja; Munn, David H.; Muller, Alexander J.; Mautino, Mario; Prendergast, George C.

    2010-01-01

    The tryptophan catabolic enzyme indoleamine 2,3-dioxygenase (IDO) has emerged as an important driver of immune escape in a growing number of cancers and cancer-associated chronic infections. In this study, we define novel immunotherapeutic applications for the heme precursor compound zinc protoporphyrin IX (ZnPP) based on our discovery that it is a potent small molecule inhibitor of IDO. Inhibitory activity was determined using in vitro and in-cell enzyme assays as well as a novel in vivo pha...

  17. Dioxygenases of Chlorobiphenyl-Degrading Species Rhodococcus wratislaviensis G10 and Chlorophenol-Degrading Species Rhodococcus opacus 1CP Induced in Benzoate-Grown Cells and Genes Potentially Involved in These Processes.

    Science.gov (United States)

    Solyanikova, I P; Borzova, O V; Emelyanova, E V; Shumkova, E S; Prisyazhnaya, N V; Plotnikova, E G; Golovleva, L A

    2016-09-01

    Dioxygenases induced during benzoate degradation by the actinobacterium Rhodococcus wratislaviensis G10 strain degrading haloaromatic compounds were studied. Rhodococcus wratislaviensis G10 completely degraded 2 g/liter benzoate during 30 h and 10 g/liter during 200 h. Washed cells grown on benzoate retained respiration activity for more than 90 days, and a high activity of benzoate dioxygenase was recorded for 10 days. Compared to the enzyme activities with benzoate, the activity of benzoate dioxygenases was 10-30% with 13 of 35 substituted benzoate analogs. Two dioxygenases capable of cleaving the aromatic ring were isolated and characterized: protocatechuate 3,4-dioxygenase and catechol 1,2-dioxygenase. Catechol inhibited the activity of protocatechuate 3,4-dioxygenase. Protocatechuate did not affect the activity of catechol 1,2-dioxygenase. A high degree of identity was shown by MALDI-TOF mass spectrometry for protein peaks of the R. wratislaviensis G10 and Rhodococcus opacus 1CP cells grown on benzoate or LB. DNA from the R. wratislaviensis G10 strain was specifically amplified using specific primers to variable regions of genes coding α- and β-subunits of protocatechuate 3,4-dioxygenase and to two genes of the R. opacus 1CP coding catechol 1,2-dioxygenase. The products were 99% identical with the corresponding regions of the R. opacus 1CP genes. This high identity (99%) between the genes coding degradation of aromatic compounds in the R. wratislaviensis G10 and R. opacus 1CP strains isolated from sites of remote location (1400 km) and at different time (20-year difference) indicates a common origin of biodegradation genes of these strains and a wide distribution of these genes among rhodococci.

  18. A "White" Anthocyanin-less Pomegranate (Punica granatum L. Caused by an Insertion in the Coding Region of the Leucoanthocyanidin Dioxygenase (LDOX; ANS Gene.

    Directory of Open Access Journals (Sweden)

    Zohar Ben-Simhon

    Full Text Available Color is an important determinant of pomegranate fruit quality and commercial value. To understand the genetic factors controlling color in pomegranate, chemical, molecular and genetic characterization of a "white" pomegranate was performed. This unique accession is lacking the typical pomegranate color rendered by anthocyanins in all tissues of the plant, including flowers, fruit (skin and arils and leaves. Steady-state gene-expression analysis indicated that none of the analyzed "white" pomegranate tissues are able to synthesize mRNA corresponding to the PgLDOX gene (leucoanthocyanidin dioxygenase, also called ANS, anthocyanidin synthase, which is one of the central structural genes in the anthocyanin-biosynthesis pathway. HPLC analysis revealed that none of the "white" pomegranate tissues accumulate anthocyanins, whereas other flavonoids, corresponding to biochemical reactions upstream of LDOX, were present. Molecular analysis of the "white" pomegranate revealed the presence of an insertion and an SNP within the coding region of PgLDOX. It was found that the SNP does not change amino acid sequence and is not fully linked with the "white" phenotype in all pomegranate accessions from the collection. On the other hand, genotyping of pomegranate accessions from the collection and segregating populations for the "white" phenotype demonstrated its complete linkage with the insertion, inherited as a recessive single-gene trait. Taken together, the results indicate that the insertion in PgLDOX is responsible for the "white" anthocyanin-less phenotype. These data provide the first direct molecular, genetic and chemical evidence for the effect of a natural modification in the LDOX gene on color accumulation in a fruit-bearing woody perennial deciduous tree. This modification can be further utilized to elucidate the physiological role of anthocyanins in protecting the tree organs from harmful environmental conditions, such as temperature and UV

  19. A "White" Anthocyanin-less Pomegranate (Punica granatum L.) Caused by an Insertion in the Coding Region of the Leucoanthocyanidin Dioxygenase (LDOX; ANS) Gene.

    Science.gov (United States)

    Ben-Simhon, Zohar; Judeinstein, Sylvie; Trainin, Taly; Harel-Beja, Rotem; Bar-Ya'akov, Irit; Borochov-Neori, Hamutal; Holland, Doron

    2015-01-01

    Color is an important determinant of pomegranate fruit quality and commercial value. To understand the genetic factors controlling color in pomegranate, chemical, molecular and genetic characterization of a "white" pomegranate was performed. This unique accession is lacking the typical pomegranate color rendered by anthocyanins in all tissues of the plant, including flowers, fruit (skin and arils) and leaves. Steady-state gene-expression analysis indicated that none of the analyzed "white" pomegranate tissues are able to synthesize mRNA corresponding to the PgLDOX gene (leucoanthocyanidin dioxygenase, also called ANS, anthocyanidin synthase), which is one of the central structural genes in the anthocyanin-biosynthesis pathway. HPLC analysis revealed that none of the "white" pomegranate tissues accumulate anthocyanins, whereas other flavonoids, corresponding to biochemical reactions upstream of LDOX, were present. Molecular analysis of the "white" pomegranate revealed the presence of an insertion and an SNP within the coding region of PgLDOX. It was found that the SNP does not change amino acid sequence and is not fully linked with the "white" phenotype in all pomegranate accessions from the collection. On the other hand, genotyping of pomegranate accessions from the collection and segregating populations for the "white" phenotype demonstrated its complete linkage with the insertion, inherited as a recessive single-gene trait. Taken together, the results indicate that the insertion in PgLDOX is responsible for the "white" anthocyanin-less phenotype. These data provide the first direct molecular, genetic and chemical evidence for the effect of a natural modification in the LDOX gene on color accumulation in a fruit-bearing woody perennial deciduous tree. This modification can be further utilized to elucidate the physiological role of anthocyanins in protecting the tree organs from harmful environmental conditions, such as temperature and UV radiation.

  20. Overexpression of the rice carotenoid cleavage dioxygenase 1 gene in Golden Rice endosperm suggests apocarotenoids as substrates in planta.

    Science.gov (United States)

    Ilg, Andrea; Yu, Qiuju; Schaub, Patrick; Beyer, Peter; Al-Babili, Salim

    2010-08-01

    Carotenoids are converted by carotenoid cleavage dioxygenases that catalyze oxidative cleavage reactions leading to apocarotenoids. However, apocarotenoids can also be further truncated by some members of this enzyme family. The plant carotenoid cleavage dioxygenase 1 (CCD1) subfamily is known to degrade both carotenoids and apocarotenoids in vitro, leading to different volatile compounds. In this study, we investigated the impact of the rice CCD1 (OsCCD1) on the pigmentation of Golden Rice 2 (GR2), a genetically modified rice variety accumulating carotenoids in the endosperm. For this purpose, the corresponding cDNA was introduced into the rice genome under the control of an endosperm-specific promoter in sense and anti-sense orientations. Despite high expression levels of OsCCD1 in sense plants, pigment analysis revealed carotenoid levels and patterns comparable to those of GR2, pleading against carotenoids as substrates in rice endosperm. In support, similar carotenoid contents were determined in anti-sense plants. To check whether OsCCD1 overexpressed in GR2 endosperm is active, in vitro assays were performed with apocarotenoid substrates. HPLC analysis confirmed the cleavage activity of introduced OsCCD1. Our data indicate that apocarotenoids rather than carotenoids are the substrates of OsCCD1 in planta.

  1. Crystallization and Preliminary X-ray Diffraction Analysis of Recombinant Chlorocatechol 1 2-dioxygenase from Pseudomonas Putida

    Energy Technology Data Exchange (ETDEWEB)

    J Rustiguel; M Pinheiro; A Araujo; M Nonato

    2011-12-31

    Chlorocatechol 1,2-dioxygenase from the Gram-negative bacterium Pseudomonas putida (Pp 1,2-CCD) is considered to be an important biotechnological tool owing to its ability to process a broad spectrum of organic pollutants. In the current work, the crystallization, crystallographic characterization and phasing of the recombinant Pp 1,2-CCD enzyme are described. Reddish-brown crystals were obtained in the presence of polyethylene glycol and magnesium acetate by utilizing the vapor-diffusion technique in sitting drops. Crystal dehydration was the key step in obtaining data sets, which were collected on the D03B-MX2 beamline at the CNPEM/MCT - LNLS using a MAR CCD detector. Pp 1,2-CCD crystals belonged to space group P6{sub 1}22 and the crystallographic structure of Pp 1,2-CCD has been solved by the MR-SAD technique using Fe atoms as scattering centres and the coordinates of 3-chlorocatechol 1,2-dioxygenase from Rhodococcus opacus (PDB entry 2boy) as the search model. The initial model, which contains three molecules in the asymmetric unit, has been refined to 3.4 {angstrom} resolution.

  2. Oxidation of indole-3-acetic acid to oxindole-3-acetic acid by an enzyme preparation from Zea mays

    Science.gov (United States)

    Reinecke, D. M.; Bandurski, R. S.

    1988-01-01

    Indole-3-acetic acid is oxidized to oxindole-3-acetic acid by Zea mays tissue extracts. Shoot, root, and endosperm tissues have enzyme activities of 1 to 10 picomoles per hour per milligram protein. The enzyme is heat labile, is soluble, and requires oxygen for activity. Cofactors of mixed function oxygenase, peroxidase, and intermolecular dioxygenase are not stimulatory to enzymic activity. A heat-stable, detergent-extractable component from corn enhances enzyme activity 6- to 10-fold. This is the first demonstration of the in vitro enzymic oxidation of indole-3-acetic acid to oxindole-3-acetic acid in higher plants.

  3. Immuno-regulatory function of indoleamine 2,3 dioxygenase through modulation of innate immune responses.

    Directory of Open Access Journals (Sweden)

    Malihe-Sadat Poormasjedi-Meibod

    Full Text Available Successful long-term treatment of type-1 diabetes mainly relies on replacement of β-cells via islet transplantation. Donor shortage is one of the main obstacles preventing transplantation from becoming the treatment of choice. Although animal organs could be an alternative source for transplantation, common immunosuppressive treatments demonstrate low efficacy in preventing xenorejection. Immunoprotective effects of indoleamine 2,3-dioxygenase (IDO on T-cell mediated allorejection has been extensively studied. Our studies revealed that IDO expression by fibroblasts, induced apoptosis in T-cells while not affecting non-immune cell survival/function. Since macrophages play a pivotal role in xenograft rejection, herein we investigated the effect of IDO-induced tryptophan deficiency/kynurenine accumulation on macrophage function/survival. Moreover, we evaluated the local immunosuppressive effect of IDO on islet-xenograft protection. Our results indicated that IDO expression by bystander fibroblasts significantly reduced the viability of primary macrophages via apoptosis induction. Treatment of peritoneal macrophages by IDO-expressing fibroblast conditioned medium significantly reduced their proinflammatory activity through inhibition of iNOS expression. To determine whether IDO-induced tryptophan starvation or kynurenine accumulation is responsible for macrophage apoptosis and inhibition of their proinflammatory activity, Raw264.7 cell viability and proinflammatory responses were evaluated in tryptophan deficient medium or in the presence of kynurenine. Tryptophan deficiency, but not kynurenine accumulation, reduced Raw264.7 cell viability and suppressed their proinflammatory activity. Next a three-dimensional islet-xenograft was engineered by embedding rat islets within either control or IDO-expressing fibroblast-populated collagen matrix. Islets morphology and immune cell infiltration were then studied in the xenografts transplanted into the C57

  4. The effects of trace elements, cations, and environmental conditions on protocatechuate 3,4-dioxygenase activity

    Directory of Open Access Journals (Sweden)

    Andréa Scaramal da Silva

    2013-04-01

    Full Text Available Phenanthracene is a highly toxic organic compound capable of contaminating water and soils, and biodegradation is an important tool for remediating polluted environments. This study aimed to evaluate the effects of trace elements, cations, and environmental conditions on the activity of the protocatechol 3,4-dioxygenase (P3,4O enzyme produced by the isolate Leifsonia sp. in cell-free and immobilized extracts. The isolate was grown in Luria Bertani broth medium (LB amended with 250 mg L-1 of phenanthrene. Various levels of pH (4.0-9.0, temperature (5-80 °C, time (0-90 min, trace elements (Cu2+, Hg2+ and Fe3+, and cations (Mg2+, Mn2+, K+ and NH4+ were tested to determine which conditions optimized enzyme activity. In general, the immobilized extract exhibited higher enzyme activity than the cell-free extract in the presence of trace elements and cations. Adding iron yielded the highest relative activity for both cell-free and immobilized extracts, with values of 16 and 99 %, respectively. Copper also increased enzyme activity for both cell-free and immobilized extracts, with values of 8 and 44 %, respectively. Enzyme activity in the phosphate buffer was high across a wide range of pH, reaching 80 % in the pH range between 6.5 and 8.0. The optimum temperatures for enzyme activity differed for cell-free and immobilized extracts, with maximum enzyme activity observed at 35 ºC for the cell-free extract and at 55 ºC for the immobilized extract. The cell-free extract of the P3,4O enzyme exhibited high activity only during the first 3 min of incubation, when it showed 50 % relative activity, and dropped to 0 % after 60 min of incubation. By contrast, activity in the immobilized extract was maintained during 90 min of incubation. This isolate has important characteristics for phenanthrene biodegradation, producing high quantities of the P3,4O enzyme that forms part of the most important pathway for PAH biodegradation.

  5. The Relationships among Tryptophan, Kynurenine, Indoleamine 2,3-Dioxygenase, Depression, and Neuropsychological Performance

    Directory of Open Access Journals (Sweden)

    Knut A. Hestad

    2017-10-01

    Full Text Available It has been suggested that the metabolic enzyme indoleamine 2,3-dioxygenase (IDO is a biological mediator of inflammation related to the psychopathology of depression, with a Kynurenine (KYN increase in the Tryptophan (TRP metabolic pathway, resulting in reduced Serotonin. In this study, we examined KYN, TRP, and the ratio of KYN to TRP concentrations × 103 (KT Ratio in serum and cerebrospinal fluid (CSF in (a a group of depressed patients and (b a control group of patients referred to a neurologic outpatient clinic for whom no specific diagnosis could be established. The KT Ratio is considered an index that represents IDO. The participants were examined with the Beck Depression Inventory II (BDI-II, the Montgomery Aasberg Depression Rating Scale (MADRS, and a neuropsychological test battery. We found no significant differences between the two study groups with respect to TRP, KYN, or KT Ratio in serum or CSF. Differences in neuropsychological performance between the two patient groups could be seen in the following tests: Animal Fluency, Digit Symbol, the DKEFS Color-Interference Test (Naming Part, Trail Making Test A and B, and the Grooved Pegboard Non-dominant Hand. KYN in serum correlated highly with KYN in CSF. KYN in serum correlated significantly with both age and gender. When analyzing males and females separately, we found that women had a lower level of TRP in both serum (Mann–Whitney U-test: TRP in Serum; p = 0.001 and CSF (Mann–Whitney U-test: TRP in CSF; p = 0.003. Women had a lower level of KYN in serum (p = 0.029 than men did. Age was positively associated with KYN. KYN in CSF correlated only with age, however; there were no gender differences. No significant relationship was seen between BDI-II and MADRS on the one hand, and KYN and TRP on the other. KYN in CSF as the KT Ratio in both serum and CSF was associated with neuropsychological performance. Thus, we suggest that KYN and KT Ratio are related more strongly to

  6. NRVS Studies of the Peroxide Shunt Intermediate in a Rieske Dioxygenase and Its Relation to the Native FesupII/supOinf2/infReaction

    Czech Academy of Sciences Publication Activity Database

    Sutherlin, K. D.; Rivard, B. S.; Böttger, L. H.; Liu, L. V.; Rogers, M. S.; Srnec, Martin; Park, K.; Yoda, Y.; Kitao, S.; Kobayashi, Y.; Saito, M.; Seto, M.; Hu, M.; Zhao, J.; Lipscomb, J. D.; Solomon, E. I.

    2018-01-01

    Roč. 140, č. 16 (2018), s. 5544-5559 ISSN 0002-7863 Institutional support: RVO:61388955 Keywords : NRVS studies * Rieske dioxygenase * mononuclear nonheme iron enzymes Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 13.858, year: 2016

  7. Long-lasting Disease Stabilization in the Absence of Toxicity in Metastatic Lung Cancer Patients Vaccinated with an Epitope Derived from Indoleamine 2,3 Dioxygenase

    DEFF Research Database (Denmark)

    Iversen, Trine Zeeberg; Engell-Noerregaard, Lotte; Ellebaek, Eva

    2014-01-01

    PURPOSE: To investigate targeting of indoleamine 2,3 dioxygenase (IDO) enzyme using a synthetic peptide vaccine administered to patients with metastatic non-small cell lung cancer (NSCLC). EXPERIMENTAL DESIGN: In a clinical phase I study, we treated 15 HLA-A2-positive patients with stage III-IV N...

  8. Purification, crystallization and preliminary X-ray diffraction studies of the three components of the toluene 2,3-dioxygenase enzyme system

    International Nuclear Information System (INIS)

    Lee, Kyoung; Friemann, Rosmarie; Parales, Juan V.; Gibson, David T.; Ramaswamy, S.

    2005-01-01

    All three components of the toluene dioxygenase system have been expressed, purified and crystallized. Pseudomonas putida F1 can grow with toluene as its sole source of carbon and energy. The initial reaction of the degradation of toluene is catalyzed by a three-component toluene dioxygenase enzyme system consisting of a reductase (Reductase TOL ), a ferredoxin (Ferredoxin TOL ) and a Rieske non-heme iron dioxygenase (Oxygenase TOL ). The three components and the apoenzyme of the dioxygenase (apo-Oxygenase TOL ) were overexpressed, purified and crystallized. Reductase TOL diffracts to 1.8 Å and belongs to space group P4 1 2 1 2, with unit-cell parameters a = b = 77.1, c = 156.3 Å. Ferredoxin TOL diffracts to 1.2 Å and belongs to space group P2 1 , with unit-cell parameters a = 30.5, b = 52.0, c = 30.95 Å, β = 113.7°. Apo-Oxygenase TOL and Oxygenase TOL diffract to 3.2 Å and belong to space group P4 3 32, with unit-cell parameters a = 235.9 Å and a = 234.5 Å, respectively

  9. NUCLEOTIDE SEQUENCING AND TRANSCRIPTIONAL MAPPING OF THE GENES ENCODING BIPHENYL DIOXYGENASE, A MULTICOM- PONENT POLYCHLORINATED-BIPHENYL-DEGRADING ENZYME IN PSEUDOMONAS STRAIN LB400

    Science.gov (United States)

    The DNA region encoding biphenyl dioxygenase, the first enzyme in the biphenyl-polychlorinated biphenyl degradation pathway of Pseudomonas species strain LB400, was sequenced. Six open reading frames were identified, four of which are homologous to the components of toluene dioxy...

  10. Highly catalytic hollow palladium nanoparticles derived from silver@silver-palladium core-shell nanostructures for the oxidation of formic acid

    Science.gov (United States)

    Chen, Dong; Cui, Penglei; He, Hongyan; Liu, Hui; Yang, Jun

    2014-12-01

    Hollow Palladium (hPd) nanoparticles (NPs) are prepared via a simple and mild successive method. Firstly, core-shell NPs with silver (Ag) cores and silver-palladium (Ag-Pd) alloy shells are synthesized in aqueous phase by galvanic replacement reaction (GRR) between Ag NPs and Pd2+ ion precursors. Saturated aqueous sodium chloride (NaCl) solution was then employed to remove the Ag component from the core and shell regions of core-shell Ag@Ag-Pd NPs, resulting in the formation of hPd NPs with shrunk sizes in comparison with their core-shell parents. Specifically, the hPd NPs exhibit superior catalytic activity and durability for catalyzing the oxidation of formic acid, compared with the Pd NPs reduced by NaBH4 in aqueous solution and commercial Pd/C catalyst from Johnson Matthey, mainly due to the large electrochemically active surface areas of the hollow particles. In addition, The Ag component in core-shell Ag@Ag-Pd NPs has an unfavorable influence on catalytic activity of NPs for formic acid oxidation. However, the durability could be improved due to the electron donating effect from Ag to Pd atoms in the core-shell NPs.

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

    Science.gov (United States)

    Silva, A.S.; Jacques, R.J.S.; Andreazza, R.; Bento, F.M.; Roesch, L.F.W.; Camargo, F.A.O.

    2013-01-01

    Polycyclic aromatic hydrocarbons (PAH) are carcinogenic compounds which contaminate water and soil, and the enzymes can be used for bioremediation of these environments. This study aimed to evaluate some environmental conditions that affect the production and activity of the catechol 1,2-dioxygenase (C12O) by Mycobacterium fortuitum in the cell free and immobilized extract in sodium alginate. The bacterium was grown in mineral medium and LB broth containing 250 mg L−1 of anthracene (PAH). The optimum conditions of pH (4.0–9.0), temperature (5–70 °C), reaction time (10–90 min) and the effect of ions in the enzyme activity were determined. The Mycobacterium cultivated in LB shown higher growth and the C12O activity was two-fold higher to that in the mineral medium. To both extracts the highest enzyme activity was at pH 8.0, however, the immobilized extract promoted the increase in the C12O activity in a pH range between 4.0 and 8.5. The immobilized extract increased the enzymatic activity time and showed the highest C12O activity at 45 °C, 20 °C higher than the greatest temperature in the cell free extract. The enzyme activity in both extracts was stimulated by Fe3+, Hg2+ and Mn2+ and inhibited by NH4+ and Cu2+, but the immobilization protected the enzyme against the deleterious effects of K+ and Mg2+ in tested concentrations. The catechol 1,2-dioxygenase of Mycobacterium fortuitum in the immobilized extract has greater stability to the variations of pH, temperature and reaction time, and show higher activity in presence of ions, comparing to the cell free extract. PMID:24159319

  12. Structure and mechanism leading to formation of the cysteine sulfinate product complex of a biomimetic cysteine dioxygenase model.

    Science.gov (United States)

    Sallmann, Madleen; Kumar, Suresh; Chernev, Petko; Nehrkorn, Joscha; Schnegg, Alexander; Kumar, Devesh; Dau, Holger; Limberg, Christian; de Visser, Sam P

    2015-05-11

    Cysteine dioxygenase is a unique nonheme iron enzyme that is involved in the metabolism of cysteine in the body. It contains an iron active site with an unusual 3-His ligation to the protein, which contrasts with the structural features of common nonheme iron dioxygenases. Recently, some of us reported a truly biomimetic model for this enzyme, namely a trispyrazolylborato iron(II) cysteinato complex, which not only has a structure very similar to the enzyme-substrate complex but also represents a functional model: Treatment of the model with dioxygen leads to cysteine dioxygenation, as shown by isolating the cysteine part of the product in the course of the work-up. However, little is known on the conversion mechanism and, so far, not even the structure of the actual product complex had been characterised, which is also unknown in case of the enzyme. In a multidisciplinary approach including density functional theory calculations and X-ray absorption spectroscopy, we have now determined the structure of the actual sulfinato complex for the first time. The Cys-SO2 (-) functional group was found to be bound in an η(2) -O,O-coordination mode, which, based on the excellent resemblance between model and enzyme, also provides the first support for a corresponding binding mode within the enzymatic product complex. Indeed, this is again confirmed by theory, which had predicted a η(2) -O,O-binding mode for synthetic as well as the natural enzyme. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Targeting Oxidative Stress, Cytokines and Serotonin Interactions Via Indoleamine 2, 3 Dioxygenase by Coenzyme Q10: Role in Suppressing Depressive Like Behavior in Rats.

    Science.gov (United States)

    Abuelezz, Sally A; Hendawy, Nevien; Magdy, Yosra

    2017-06-01

    Depression is a major health problem in which oxidative stress and inflammation are inextricably connected in its pathophysiology. Coenzyme Q10 (CoQ10) is an important anti-oxidant compound with anti-inflammatory and neuro-protective properties. This study was designed to investigate the hypothesis that CoQ10 by its anti-oxidant and anti-inflammatory potentials can alleviate depressive- like behavior by restoring the balance of the tryptophan catabolites kynurenine/serotonin toward the serotonin pathway by down-regulation of hippocampal indoleamine 2,3-dioxygenase 1 (IDO-1). Depressive-like behavior was induced by chronic unpredictable mild stress (CUMS) protocol including food or water deprivation, cage tilting, reversed light cycle etc. Male Wistar rats were randomly divided into five groups; Control, CUMS, CUMS and CoQ10 (50,100 and 200 mg/kg/day i.p. respectively) groups. CoQ10 effects on different behavioral and biochemical tests were analyzed. CoQ10 showed significant antidepressant efficacy, as evidenced by significantly decreased stress induced changes to forced swimming challenge and open field test, as well as attenuating raised corticosterone level and adrenal glands weight. The anti-oxidant effect of CoQ10 was exhibited by its ability to significantly reduce hippocampal elevated malondialdehyde and 4-hydroxynonenal levels and elevate the reduced glutathione and catalase levels. CoQ10 significantly reduced different pro-inflammatory cytokines levels including interleukin (IL)-1β, IL-2, IL-6 and tumor necrosis factor-α. It suppressed hippocampal IDO-1 and subsequent production of kynurenine and enhanced the hippocampal contents of tryptophan and serotonin. Immunohistochemical analysis revealed that CoQ10 was able to attenuate the elevated microglial CD68 and elevate the astrocyte glial fibrillary acidic protein compared to CUMS group. CoQ10 exhibited antidepressant-like effects on rats exposed to CUMS. This could be attributed to its ability to reduce

  14. Indoleamine 2,3-dioxygenase-expressing leukemic dendritic cells impair a leukemia-specific immune response by inducing potent T regulatory cells

    OpenAIRE

    Curti, A; Trabanelli, S; Onofri, C; Aluigi, M; Salvestrini, V; Ocadlikova, D; Evangelisti, C; Rutella, S; De Cristofaro, R; Ottaviani, E; Baccarani, M; Lemoli, RM

    2010-01-01

    Background: The immunoregulatory enzyme indoleamine 2,3-dioxygenase, which catalyzes the conversion of tryptophan into kynurenine, is expressed in a significant subset of patients with acute myeloid leukemia, resulting in the inhibition of T-cell proliferation and the induction of regulatory T cells. Acute myeloid leukemia cells can be differentiated into dendritic cells, which have increased immunogenicity and have been proposed as vaccines against leukemia.\\ud Design and Methods: Leukemic d...

  15. Ability of bacterial biphenyl dioxygenases from Burkholderia sp. LB400 and Comamonas testosteroni B-356 to catalyse oxygenation of ortho-hydroxychlorobiphenyls formed from PCBs by plants

    Czech Academy of Sciences Publication Activity Database

    Francová, K.; Macková, M.; Macek, Tomáš; Sylvestre, M.

    2004-01-01

    Roč. 127, - (2004), s. 41-48 ISSN 0269-7491 R&D Projects: GA ČR GA526/01/1292 Grant - others:Natural Science and Engineering Research(CA) RGPIN39579-02; NATO Collaborative linkage(XE) SA(EST.GLC.977477)5941SA Institutional research plan: CEZ:AV0Z4055905 Keywords : PCB degradation * biphenyl dioxygenases * enzyme specificity Subject RIV: CE - Biochemistry Impact factor: 2.205, year: 2004

  16. Remarkable Role of Indoleamine 2,3-Dioxygenase and Tryptophan Metabolites in Infectious Diseases: Potential Role in Macrophage-Mediated Inflammatory Diseases

    OpenAIRE

    Murakami, Yuki; Hoshi, Masato; Imamura, Yukio; Arioka, Yuko; Yamamoto, Yasuko; Saito, Kuniaki

    2013-01-01

    Indoleamine 2,3-dioxygenase 1 (IDO1), the L-tryptophan-degrading enzyme, plays a key role in the immunomodulatory effects on several types of immune cells. Originally known for its regulatory function during pregnancy and chronic inflammation in tumorigenesis, the activity of IDO1 seems to modify the inflammatory state of infectious diseases. The pathophysiologic activity of L-tryptophan metabolites, kynurenines, is well recognized. Therefore, an understanding of the regulation of IDO1 and th...

  17. Dietary Fatty Acids Alter Lipid Profiles and Induce Myocardial Dysfunction without Causing Metabolic Disorders in Mice.

    Science.gov (United States)

    Chen, Bainian; Huang, Yifan; Zheng, Dong; Ni, Rui; Bernards, Mark A

    2018-01-19

    Oversupply of bulk saturated fatty acids (SFA) induces metabolic disorders and myocardial dysfunction. We investigated whether, without causing metabolic disorders, the uptake of individual dietary SFA species alters lipid profiles and induces myocardial dysfunction. C57BL/6 mice were fed various customized long-chain SFA diets (40% caloric intake from SFA), including a beef tallow (HBD), cocoa butter (HCD), milk fat (HMD) and palm oil diet (HPD), for 6 months. An isocaloric fat diet, containing medium-chain triglycerides, served as a control (CHD). Long-term intake of dietary long-chain SFA differentially affected the fatty acid composition in cardiac phospholipids. All long-chain SFA diets increased the levels of arachidonic acid and total SFA in cardiac phospholipids. The preferential incorporation of individual SFA into the cardiac phospholipid fraction was dependent on the dietary SFA species. Cardiac ceramide content was elevated in all mice fed long-chain SFA diets, while cardiac hypertrophy was only presented in mice fed HMD or HPD. We have demonstrated that the intake of long-chain SFA species differentially alters cardiac lipid profiles and induces cardiac dysfunction, without causing remarkable metabolic disorders.

  18. The indoleamine-2,3-dioxygenase (IDO inhibitor 1-methyl-D-tryptophan upregulates IDO1 in human cancer cells.

    Directory of Open Access Journals (Sweden)

    Christiane A Opitz

    Full Text Available 1-methyl-D-tryptophan (1-D-MT is currently being used in clinical trials in patients with relapsed or refractory solid tumors with the aim of inhibiting indoleamine-2,3-dioxygenase (IDO-mediated tumor immune escape. IDO is expressed in tumors and tumor-draining lymph nodes and degrades tryptophan (trp to create an immunsuppressive micromilieu both by depleting trp and by accumulating immunosuppressive metabolites of the kynurenine (kyn pathway. Here we show that proliferation of alloreactive T-cells cocultured with IDO1-positive human cancer cells paradoxically was inhibited by 1-D-MT. Surprisingly incubation with 1-D-MT increased kyn production of human cancer cells. Cell-free assays revealed that 1-D-MT did not alter IDO1 enzymatic activity. Instead, 1-D-MT induced IDO1 mRNA and protein expression through pathways involving p38 MAPK and JNK signalling. Treatment of cancer patients with 1-D-MT has transcriptional effects that may promote rather than suppress anti-tumor immune escape by increasing IDO1 in the cancer cells. These off-target effects should be carefully analyzed in the ongoing clinical trials with 1-D-MT.

  19. Ethylnaphthoquinone derivatives as inhibitors of indoleamine-2, 3-dioxygenase from the mangrove endophytic fungus Neofusicoccum austral SYSU-SKS024.

    Science.gov (United States)

    Cui, Hui; Zhang, Hongao; Liu, Yena; Gu, Qiong; Xu, Jun; Huang, Xishan; She, Zhigang

    2018-03-01

    Bioassay-guided fractionation of the dichloromethane extract of the fungus Neofusicoccum austral SYSU-SKS024 led to the isolation of three new ethylnaphthoquinone derivatives, neofusnaphthoquinone A (1), 6-(1-methoxylethy1)-2,7-dimethoxyjuglone (2), (3R,4R)-3-methoxyl-botryosphaerone D (6), together with six known analogs (3-5 and 7-9). Their structures were elucidated by spectroscopic analysis and single crystal X-ray diffraction analysis. Neofusnaphthoquinone A (1) is the third example of the unsymmetrical naphthoquinone dimer, which is rarely found in natural source. All of the isolates were evaluated for their indoleamine 2, 3-dioxygenase (IDO) inhibitory activity, compounds 1-6 showed in vitro inhibitory effects against IDO with IC 50 values ranging from 0.11 to 10.92μM. This is the first time naphthoquinone dimer (1), as a novel carbon skeleton possessing IDO inhibitory activity, was reported. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Zinc protoporphyrin-IX stimulates tumor immunity by disrupting the immunosuppressive enzyme indoleamine 2,3-dioxygenase

    Science.gov (United States)

    Metz, Richard; DuHadaway, James B.; Rust, Sonja; Munn, David H.; Muller, Alexander J.; Mautino, Mario; Prendergast, George C.

    2010-01-01

    The tryptophan catabolic enzyme indoleamine 2,3-dioxygenase (IDO) has emerged as an important driver of immune escape in a growing number of cancers and cancer-associated chronic infections. In this study, we define novel immunotherapeutic applications for the heme precursor compound zinc protoporphyrin IX (ZnPP) based on our discovery that it is a potent small molecule inhibitor of IDO. Inhibitory activity was determined using in vitro and in-cell enzyme assays as well as a novel in vivo pharmacodynamic system. An irreversible mechanism of inhibition was documented consistent with competition for heme binding in newly synthesized cellular protein. siRNA methodology and an IDO-deficient mouse strain were used to verify specificity as an IDO inhibitor. In a preclinical model of melanoma, ZnPP displayed antitumor properties that relied upon T cell function and IDO integrity. ZnPP also phenocopied the known antitumor properties of IDO inhibitors in preclinical models of skin and breast carcinoma. Our results suggest clinical evaluation of ZnPP as an adjuvant immunochemotherapy in chronic infections and cancers where there is emerging recognition of a pathophysiological role for IDO dysregulation. PMID:20530717

  1. Expression of tryptophan 2,3-dioxygenase in mature granule cells of the adult mouse dentate gyrus

    Directory of Open Access Journals (Sweden)

    Ohira, Koji

    2010-09-01

    Full Text Available Abstract New granule cells are continuously generated in the dentate gyrus of the adult hippocampus. During granule cell maturation, the mechanisms that differentiate new cells not only describe the degree of cell differentiation, but also crucially regulate the progression of cell differentiation. Here, we describe a gene, tryptophan 2,3-dioxygenase (TDO, whose expression distinguishes stem cells from more differentiated cells among the granule cells of the adult mouse dentate gyrus. The use of markers for proliferation, neural progenitors, and immature and mature granule cells indicated that TDO was expressed in mature cells and in some immature cells. In mice heterozygous for the alpha-isoform of calcium/calmodulin-dependent protein kinase II, in which dentate gyrus granule cells fail to mature normally, TDO immunoreactivity was substantially downregulated in the dentate gyrus granule cells. Moreover, a 5-bromo-2'-deoxyuridine labeling experiment revealed that new neurons began to express TDO between 2 and 4 wk after the neurons were generated, when the axons and dendrites of the granule cells developed and synaptogenesis occurred. These findings indicate that TDO might be required at a late-stage of granule cell development, such as during axonal and dendritic growth, synaptogenesis and its maturation.

  2. Disruption of a CAROTENOID CLEAVAGE DIOXYGENASE 4 gene converts flower colour from white to yellow in Brassica species.

    Science.gov (United States)

    Zhang, Bao; Liu, Chao; Wang, Yaqin; Yao, Xuan; Wang, Fang; Wu, Jiangsheng; King, Graham J; Liu, Kede

    2015-06-01

    In Brassica napus, yellow petals had a much higher content of carotenoids than white petals present in a small number of lines, with violaxanthin identified as the major carotenoid compound in yellow petals of rapeseed lines. Using positional cloning we identified a carotenoid cleavage dioxygenase 4 gene, BnaC3.CCD4, responsible for the formation of flower colour, with preferential expression in petals of white-flowered B. napus lines. Insertion of a CACTA-like transposable element 1 (TE1) into the coding region of BnaC3.CCD4 had disrupted its expression in yellow-flowered rapeseed lines. α-Ionone was identified as the major volatile apocarotenoid released from white petals but not from yellow petals. We speculate that BnaC3.CCD4 may use δ- and/or α-carotene as substrates. Four variations, including two CACTA-like TEs (alleles M1 and M4) and two insertion/deletions (INDELs, alleles M2 and M3), were identified in yellow-flowered Brassica oleracea lines. The two CACTA-like TEs were also identified in the coding region of BcaC3.CCD4 in Brassica carinata. However, the two INDELs were not detected in B. napus and B. carinata. We demonstrate that the insertions of TEs in BolC3.CCD4 predated the formation of the two allotetraploids. © 2015 The Authors New Phytologist © 2015 New Phytologist Trust.

  3. Cyclooxygenase-2 (COX-2 Inhibition Constrains Indoleamine 2,3-Dioxygenase 1 (IDO1 Activity in Acute Myeloid Leukaemia Cells

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    Sergio Rutella

    2013-08-01

    Full Text Available Indoleamine 2,3-dioxygenase 1 (IDO1 metabolizes L-tryptophan to kynurenines (KYN, inducing T-cell suppression either directly or by altering antigen-presenting-cell function. Cyclooxygenase (COX-2, the rate-limiting enzyme in the synthesis of prostaglandins, is over-expressed by several tumours. We aimed at determining whether COX-2 inhibitors down-regulate the IFN-g-induced expression of IDO1 in acute myeloid leukaemia (AML cells. IFN-γ at 100 ng/mL up-regulated COX-2 and IDO1 in HL-60 AML cells, both at mRNA and protein level. The increased COX-2 and IDO1 expression correlated with heightened production of prostaglandin (PGE2 and kynurenines, respectively. Nimesulide, a preferential COX-2 inhibitor, down-regulated IDO1 mRNA/protein and attenuated kynurenine synthesis, suggesting that overall IDO inhibition resulted both from reduced IDO1 gene transcription and from inhibited IDO1 catalytic activity. From a functional standpoint, IFN-g-challenged HL-60 cells promoted the in vitro conversion of allogeneic CD4+CD25− T cells into bona fide CD4+CD25+FoxP3+ regulatory T cells, an effect that was significantly reduced by treatment of IFN-γ-activated HL-60 cells with nimesulide. Overall, these data point to COX-2 inhibition as a potential strategy to be pursued with the aim at circumventing leukaemia-induced, IDO-mediated immune dysfunction.

  4. Dioxygenases Catalyze O-Demethylation and O,O-Demethylenation with Widespread Roles in Benzylisoquinoline Alkaloid Metabolism in Opium Poppy*

    Science.gov (United States)

    Farrow, Scott C.; Facchini, Peter J.

    2013-01-01

    In opium poppy, the antepenultimate and final steps in morphine biosynthesis are catalyzed by the 2-oxoglutarate/Fe(II)-dependent dioxygenases, thebaine 6-O-demethylase (T6ODM) and codeine O-demethylase (CODM). Further investigation into the biochemical functions of CODM and T6ODM revealed extensive and unexpected roles for such enzymes in the metabolism of protopine, benzo[c]phenanthridine, and rhoeadine alkaloids. When assayed with a wide range of benzylisoquinoline alkaloids, CODM, T6ODM, and the functionally unassigned paralog DIOX2, renamed protopine O-dealkylase, showed novel and efficient dealkylation activities, including regio- and substrate-specific O-demethylation and O,O-demethylenation. Enzymes catalyzing O,O-demethylenation, which cleave a methylenedioxy bridge leaving two hydroxyl groups, have previously not been reported in plants. Similar cleavage of methylenedioxy bridges on substituted amphetamines is catalyzed by heme-dependent cytochromes P450 in mammals. Preferred substrates for O,O-demethylenation by CODM and protopine O-dealkylase were protopine alkaloids that serve as intermediates in the biosynthesis of benzo[c]phenanthridine and rhoeadine derivatives. Virus-induced gene silencing used to suppress the abundance of CODM and/or T6ODM transcripts indicated a direct physiological role for these enzymes in the metabolism of protopine alkaloids, and they revealed their indirect involvement in the formation of the antimicrobial benzo[c]phenanthridine sanguinarine and certain rhoeadine alkaloids in opium poppy. PMID:23928311

  5. Dioxygenases catalyze O-demethylation and O,O-demethylenation with widespread roles in benzylisoquinoline alkaloid metabolism in opium poppy.

    Science.gov (United States)

    Farrow, Scott C; Facchini, Peter J

    2013-10-04

    In opium poppy, the antepenultimate and final steps in morphine biosynthesis are catalyzed by the 2-oxoglutarate/Fe(II)-dependent dioxygenases, thebaine 6-O-demethylase (T6ODM) and codeine O-demethylase (CODM). Further investigation into the biochemical functions of CODM and T6ODM revealed extensive and unexpected roles for such enzymes in the metabolism of protopine, benzo[c]phenanthridine, and rhoeadine alkaloids. When assayed with a wide range of benzylisoquinoline alkaloids, CODM, T6ODM, and the functionally unassigned paralog DIOX2, renamed protopine O-dealkylase, showed novel and efficient dealkylation activities, including regio- and substrate-specific O-demethylation and O,O-demethylenation. Enzymes catalyzing O,O-demethylenation, which cleave a methylenedioxy bridge leaving two hydroxyl groups, have previously not been reported in plants. Similar cleavage of methylenedioxy bridges on substituted amphetamines is catalyzed by heme-dependent cytochromes P450 in mammals. Preferred substrates for O,O-demethylenation by CODM and protopine O-dealkylase were protopine alkaloids that serve as intermediates in the biosynthesis of benzo[c]phenanthridine and rhoeadine derivatives. Virus-induced gene silencing used to suppress the abundance of CODM and/or T6ODM transcripts indicated a direct physiological role for these enzymes in the metabolism of protopine alkaloids, and they revealed their indirect involvement in the formation of the antimicrobial benzo[c]phenanthridine sanguinarine and certain rhoeadine alkaloids in opium poppy.

  6. Eosinophil Granulocytes Account for Indoleamine 2,3-Dioxygenase-Mediated Immune Escape in Human Non Small Cell Lung Cancer

    Directory of Open Access Journals (Sweden)

    Simonetta Astigiano

    2005-04-01

    Full Text Available Indoleamine 2,3-dioxygenase (IDO, a catabolizing enzyme of tryptophan, is supposed to play a role in tumor immune escape. Its expression in solid tumors has not yet been well elucidated: IDO can be expressed by the tumor cells themselves, or by ill-defined infiltrating cells, possibly depending on tumor type. We have investigated IDO expression in 25 cases of non small cell lung cancer (NSCLC. Using histochemistry and immunohistochemistry, we found that IDO was expressed not by tumor cells, but by normal cells infiltrating the peritumoral stroma. These cells were neither macrophages nor dendritic cells, and were identified as eosinophil granulocytes. The amount of IDO-positive eosinophils varied in different cases, ranging from a few cells to more than 50 per field at x200 magnification. IDO protein in NSCLC was enzymatically active. Therefore, at least in NSCLC cases displaying a large amount of these cells in the inflammatory infiltrate, IDO-positive eosinophils could exert an effective immunosuppressive action. On analyzing the 17 patients with adequate follow-up, a significant relationship was found between the amount of IDO-positive infiltrate and overall survival. This finding suggests that the degree of IDO-positive infiltrate could be a prognostic marker in NSCLC.

  7. 4-Bromophenylhydrazinyl benzenesulfonylphenylureas as indoleamine 2,3-dioxygenase inhibitors with in vivo target inhibition and anti-tumor efficacy.

    Science.gov (United States)

    Lin, Shu-Yu; Yeh, Teng-Kuang; Song, Jen-Shin; Hung, Ming-Shiu; Cheng, Ming-Fu; Liao, Fang-Yu; Li, An-Shiou; Cheng, Shu-Ying; Lin, Li-Mei; Chiu, Chun-Hsien; Wu, Mine-Hsine; Lin, Yi-Jyun; Hsiao, Wenchi; Sun, Manwu; Wang, Yi-Hsin; Huang, Chin-Hsiang; Tang, Ya-Chu; Chang, Hsin-Huei; Huang, Zih-Ting; Chao, Yu-Sheng; Shih, Chuan; Pan, Shiow-Lin; Wu, Su-Ying; Kuo, Ching-Chuan; Ueng, Shau-Hua

    2018-02-12

    Indoleamine 2,3-dioxygenase is a heme-containing enzyme implicated in the down regulation of the anti-tumor immune response, and considered a promising anti-cancer drug target. Several pharmaceutical companies, including Pfizer, Merck, and Bristol-Myers Squibb, are known to be in pursuit of IDO inhibitors, and Incyte recently reported good results in the phase II clinical trial of the IDO inhibitor Epacadostat. In previous work, we developed a series of IDO inhibitors based on a sulfonylhydrazide core structure, and explored how they could serve as potent IDO inhibitors with good drug profiles. Herein, we disclose the development of the 4-bromophenylhydrazinyl benzenesulfonylphenylurea 5k, a potent IDO inhibitor which demonstrated 25% tumor growth inhibition in a murine CT26 syngeneic model on day 18 with 100 mg/kg oral administration twice daily, and a 30% reduction in tumor weight. Pharmacodynamic testing of 5k found it to cause a 25% and 21% reduction in kyn/trp ratio at the plasma and tumor, respectively. In the CT26 tumor model, 5k was found to slightly increase the percentage of CD3 + T cells and lymphocyte responsiveness, indicating that 5k may have potential in modulating anti-tumor immunity. These data suggest 5k to be worthy of further investigation in the development of anti-tumor drugs. Copyright © 2018 Elsevier Inc. All rights reserved.

  8. One enzyme, many reactions: structural basis for the various reactions catalyzed by naphthalene 1,2-dioxygenase

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    Daniel J. Ferraro

    2017-09-01

    Full Text Available Rieske nonheme iron oxygenases (ROs are a well studied class of enzymes. Naphthalene 1,2-dioxygenase (NDO is used as a model to study ROs. Previous work has shown how side-on binding of oxygen to the mononuclear iron provides this enzyme with the ability to catalyze stereospecific and regiospecific cis-dihydroxylation reactions. It has been well documented that ROs catalyze a variety of other reactions, including mono-oxygenation, desaturation, O- and N-dealkylation, sulfoxidation etc. NDO itself catalyzes a variety of these reactions. Structures of NDO in complex with a number of different substrates show that the orientation of the substrate in the active site controls not only the regiospecificity and stereospecificity, but also the type of reaction catalyzed. It is proposed that the mononuclear iron-activated dioxygen attacks the atoms of the substrate that are most proximal to it. The promiscuity of delivering two products (apparently by two different reactions from the same substrate can be explained by the possible binding of the substrate in slightly different orientations aided by the observed flexibility of residues in the binding pocket.

  9. Indoleamine 2,3-dioxygenase 1 (IDO1 activity correlates with immune system abnormalities in multiple myeloma

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    Bonanno Giuseppina

    2012-12-01

    Full Text Available Abstract Background Multiple myeloma (MM is a plasma cell malignancy with a multifaceted immune dysfunction. Indoleamine 2,3-dioxygenase 1 (IDO1 degrades tryptophan into kynurenine (KYN, which inhibits effector T cells and promote regulatory T-cell (Treg differentiation. It is presently unknown whether MM cells express IDO1 and whether IDO1 activity correlates with immune system impairment. Methods We investigated IDO1 expression in 25 consecutive patients with symptomatic MM and in 7 patients with either monoclonal gammopathy of unknown significance (MGUS; n=3 or smoldering MM (SMM; n=4. IDO1-driven tryptophan breakdown was correlated with the release of hepatocyte growth factor (HGF and with the frequency of Treg cells and NY-ESO-1-specific CD8+ T cells. Results KYN was increased in 75% of patients with symptomatic MM and correlated with the expansion of CD4+CD25+FoxP3+ Treg cells and the contraction of NY-ESO-1-specific CD8+ T cells. In vitro, primary MM cells promoted the differentiation of allogeneic CD4+ T cells into bona fide CD4+CD25hiFoxP3hi Treg cells and suppressed IFN-γ/IL-2 secretion, while preserving IL-4 and IL-10 production. Both Treg expansion and inhibition of Th1 differentiation by MM cells were reverted, at least in part, by d,l-1-methyl-tryptophan, a chemical inhibitor of IDO. Notably, HGF levels were higher within the BM microenvironment of patients with IDO+ myeloma disease compared with patients having IDO- MM. Mechanistically, the antagonism of MET receptor for HGF with SU11274, a MET inhibitor, prevented HGF-induced AKT phosphorylation in MM cells and translated into reduced IDO protein levels and functional activity. Conclusions These data suggest that IDO1 expression may contribute to immune suppression in patients with MM and possibly other HGF-producing cancers.

  10. Inhibition of indoleamine 2,3-dioxygenase prevented cognitive impairment in adult Wistar rats subjected to pneumococcal meningitis.

    Science.gov (United States)

    Barichello, Tatiana; Generoso, Jaqueline S; Simões, Lutiana R; Elias, Samuel G; Tashiro, Michael H; Dominguini, Diogo; Comim, Clarissa M; Vilela, Márcia Carvalho; Teixeira, Antonio Lucio; Quevedo, João

    2013-12-01

    Streptococcus pneumoniae is a common cause of forms of bacterial meningitis that have a high mortality rate and cause long-term neurologic sequelae. We evaluated the effects of an indoleamine 2,3-dioxygenase (IDO) inhibitor on proinflammatory mediators and memory in Wistar rats subjected to pneumococcal meningitis. The animals were divided into 4 groups: sham, sham treated with IDO inhibitor, meningitis, and meningitis treated with IDO inhibitor. During the first experiment, the animals were killed 24 hours later, and the hippocampus was isolated for the analysis of tumor necrosis factor (TNF)-α, interleukin (IL)-4, IL-6, IL-10, and cytokine-induced neutrophil chemoattractant 1 (CINC-1) levels. The survival rate was 56.296% in the meningitis group and 29.616% in the meningitis group with IDO inhibitor. In the control group, we found a mean of 14.29 white blood cells/mL cerebrospinal fluid, whereas the mean was 80.00 white blood cells/mL cerebrospinal fluid in the sham IDO inhibitor group, 1167.00 white blood cells/mL cerebrospinal fluid in the meningitis group, and 286.70 white blood cells/mL cerebrospinal fluid in the meningitis IDO inhibitor group. In the meningitis group with IDO inhibitor, the levels of TNF-α and CINC-1 were reduced. In the second experiment, animals were subjected to a behavioral task and cytokine analysis 10 days after meningitis induction. In the meningitis group, there was an impairment of aversive memory. However, in the meningitis group that received adjuvant treatment with the IDO inhibitor, animals demonstrated preservation of aversive memory. These findings showed dual effects of the IDO inhibitor on a pneumococcal meningitis animal model because the inhibitor impaired survival but also produced beneficial effects, including anti-inflammatory activity and neuroprotection against the latter behavioral deficits. Copyright © 2013 Mosby, Inc. All rights reserved.

  11. Influence of Tryptophan Contained in 1-Methyl-Tryptophan on Antimicrobial and Immunoregulatory Functions of Indoleamine 2,3-Dioxygenase

    Science.gov (United States)

    Schmidt, Silvia K.; Siepmann, Stephan; Kuhlmann, Katja; Meyer, Helmut E.; Metzger, Sabine; Pudelko, Sabine; Leineweber, Margret; Däubener, Walter

    2012-01-01

    Indoleamine 2,3-dioxygenase (IDO) has been identified as an important antimicrobial and immunoregulatory effector molecule essential for the establishment of tolerance by regulating local tryptophan (Trp) concentrations. On the other hand, the immunosuppressive capacity of IDO can have detrimental effects for the host as it can lead to deleterious alterations of the immune response by promoting tolerance to some types of tumors. To suppress this disadvantageous IDO effect, the competitive inhibitor 1-Methyl-Tryptophan (1-MT) is being tested in clinical trials. However, it remains inconclusive which stereoisomer of 1-MT is the more effective inhibitor of IDO-mediated immunosuppression. While IDO enzyme activity is more efficiently inhibited by 1-L-MT in cell-free or in vitro settings, 1-D-MT is superior to 1-L-MT in the enhancement of anti-tumor responses in vivo. Here, we present new data showing that commercially available 1-L-MT lots contain tryptophan in amounts sufficient to compensate for the IDO-mediated tryptophan depletion in vitro. The addition of 1-L-MT abrogated IDO-mediated antimicrobial effects and permitted the growth of the tryptophan-auxotroph microorganisms Staphylococcus aureus and Toxoplasma gondii. Consistent with this, the tryptophan within 1-L-MT lots was sufficient to antagonize IDO-mediated inhibition of T cell responses. Mass spectrometry (MS) analysis revealed not only tryptophan within 1-L-MT, but also the incorporation of this tryptophan in bacterial and human proteins that were generated in the presence of 1-L-MT in otherwise tryptophan-free conditions. In summary, these data reveal that tryptophan within 1-L-MT can affect the results of in vitro studies in an L-stereospecific and IDO-independent way. PMID:23028625

  12. Modulatory roles of interferon-γ through indoleamine 2, 3-dioxygenase induction in innate immune response of dental pulp cells.

    Science.gov (United States)

    Takegawa, Daisuke; Nakanishi, Tadashi; Hirao, Kouji; Yumoto, Hiromichi; Takahashi, Kanako; Matsuo, Takashi

    2014-09-01

    Marked infiltration of inflammatory cells such as activated T cells producing interferon-γ (IFN-γ) is observed in severe pulpitis. However, the roles of IFN-γ in the innate immune response of dental pulp have not been reported. Indoleamine 2, 3-dioxygenase (IDO) is a regulator of immune responses, and the IDO expression is induced by IFN-γ in many cells whose expression in dental pulp is unknown. The purpose of this study was to determine the role of IFN-γ in the immune response through microbial pattern recognition receptors (PRRs) such as Toll-like receptors or nucleotide-binding oligomerization domain-like receptors on the production of proinflammatory cytokines such as CXCL10 and interleukin (IL)-6 and the expression of IDO in cultured human dental pulp cells (HDPCs). HDPCs were established from explant cultures of healthy pulp tissues. CXCL10 and IL-6 production was determined using enzyme-linked immunosorbent assay. Confirmation of IDO localization in dental pulp tissues was examined using immunohistochemistry. IDO expression in HDPCs was analyzed by immunoblot. IFN-γ significantly up-regulated CXCL10 and IL-6 production in the HDPCs stimulated with ligands for PRRs in a concentration-dependent manner. The expression of IDO was detected in inflamed pulp tissue. In addition, IFN-γ in combination with the PRR ligands enhanced IDO expression in HDPCs compared with IFN-γ alone. Moreover, CXCL10 production in IFN-γ-stimulated HDPCs was inhibited by an IDO inhibitor. This study showed the synergistic effects by IFN-γ on cytokine production and IDO expression in HDPCs, suggesting that IFN-γ may modulate the innate immune response of dental pulp. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  13. Prognostic Significance of Promoter DNA Hypermethylation of cysteine dioxygenase 1 (CDO1 Gene in Primary Breast Cancer.

    Directory of Open Access Journals (Sweden)

    Naoko Minatani

    Full Text Available Using pharmacological unmasking microarray, we identified promoter DNA methylation of cysteine dioxygenase 1 (CDO1 gene in human cancer. In this study, we assessed the clinicopathological significance of CDO1 methylation in primary breast cancer (BC with no prior chemotherapy. The CDO1 DNA methylation was quantified by TaqMan methylation specific PCR (Q-MSP in 7 BC cell lines and 172 primary BC patients with no prior chemotherapy. Promoter DNA of the CDO1 gene was hypermethylated in 6 BC cell lines except SK-BR3, and CDO1 gene expression was all silenced at mRNA level in the 7 BC cell lines. Quantification of CDO1 methylation was developed using Q-MSP, and assessed in primary BC. Among the clinicopathologic factors, CDO1 methylation level was not statistically significantly associated with any prognostic factors. The log-rank plot analysis elucidated that the higher methylation the tumors harbored, the poorer prognosis the patients exhibited. Using the median value of 58.0 as a cut-off one, disease specific survival in BC patients with CDO1 hypermethylation showed significantly poorer prognosis than those with hypomethylation (p = 0.004. Multivariate Cox proportional hazards model identified that CDO1 hypermethylation was prognostic factor as well as Ki-67 and hormone receptor status. The most intriguingly, CDO1 hypermethylation was of robust prognostic relevance in triple negative BC (p = 0.007. Promoter DNA methylation of CDO1 gene was robust prognostic indicator in primary BC patients with no prior chemotherapy. Prognostic relevance of the CDO1 promoter DNA methylation is worthy of being paid attention in triple negative BC cancer.

  14. Effect of Indoleamine 2,3-Dioxygenase Expressed in HTR-8/SVneo Cells on Decidual NK Cell Cytotoxicity.

    Science.gov (United States)

    Ban, Yanli; Zhao, Ying; Liu, Fen; Dong, Baihua; Kong, Beihua; Qu, Xun

    2016-05-01

    To study the effect of indoleamine 2,3-dioxygenase (IDO) expressed in HTR-8/SVneo cells on NKG2D and NKp46 expression and cytotoxicity of decidual NK (dNK) and peripheral NK (pNK) cells. CD56(+) dNK and pNK cells purified were cultured with HTR-8/SVneo cell conditioned medium (CM), 1-MT+HTR-8/SVneo cell CM, and complete RPMI 1640 medium (negative control) in vitro. The mRNA and protein expression of NKG2D and NKp46 in NK cells were then assessed by qRT-PCR and flow cytometry, respectively. Their cytotoxicity was evaluated with LDH assays, and TNF-α secretion was analyzed by ELISA. For dNK cells, the mRNA and protein expression of NKp46 as well as NKG2D did not differ significantly among the three groups (P > 0.05), whereas for pNK cells, the expression level was significantly decreased in HTR-8/SVneo cell CM group than the other two groups (P cytotoxicity and TNF-α secretion than the other two groups (P 0.05). IDO expressed by HTR-8/SVneo cells can down-regulate NKp46 and NKG2D expression and reduce cytotoxicity in pNK cells, and may contribute to keep dNK cytotoxicity at a low level, suggesting an important role for IDO in the maintenance of normal pregnancy. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. GENETIC ANALYSIS OF ABSCISIC ACID BIOSYNTHESIS

    Energy Technology Data Exchange (ETDEWEB)

    MCCARTY D R

    2012-01-10

    The carotenoid cleavage dioxygenases (CCD) catalyze synthesis of a variety of apo-carotenoid secondary metabolites in plants, animals and bacteria. In plants, the reaction catalyzed by the 11, 12, 9-cis-epoxy carotenoid dioxygenase (NCED) is the first committed and key regulated step in synthesis of the plant hormone, abscisic acid (ABA). ABA is a key regulator of plant stress responses and has critical functions in normal root and seed development. The molecular mechanisms responsible for developmental control of ABA synthesis in plant tissues are poorly understood. Five of the nine CCD genes present in the Arabidopsis genome encode NCED's involved in control of ABA synthesis in the plant. This project is focused on functional analysis of these five AtNCED genes as a key to understanding developmental regulation of ABA synthesis and dissecting the role of ABA in plant development. For this purpose, the project developed a comprehensive set of gene knockouts in the AtNCED genes that facilitate genetic dissection of ABA synthesis. These mutants were used in combination with key molecular tools to address the following specific objectives: (1) the role of ABA synthesis in root development; (2) developmental control of ABA synthesis in seeds; (3) analysis of ATNCED over-expressers; (4) preliminary crystallography of the maize VP14 protein.

  16. Evidence that pcpA encodes 2,6-dichlorohydroquinone dioxygenase, the ring cleavage enzyme required for pentachlorophenol degradation in Sphingomonas chlorophenolica strain ATCC 39723.

    Science.gov (United States)

    Xu, L; Resing, K; Lawson, S L; Babbitt, P C; Copley, S D

    1999-06-15

    An enzyme that catalyzes an Fe2+-dependent reaction of 2, 6-dichlorohydroquinone with O2 has been isolated from Sphingomonas chlorophenolica sp. strain ATCC 39723, a soil microorganism capable of complete mineralization of pentachlorophenol. The product of the reaction is too unstable to allow spectroscopic characterization, but is apparently negatively charged and retains the two chlorine atoms of the substrate. The enzyme was partially sequenced using electrospray LC-MS, and one peptide was used to search the NCBInr database. This peptide matched a part of PcpA, a protein of unknown function that is induced in S. chlorophenolica in response to pentachlorophenol. Several other peptides could also be mapped onto the sequence of PcpA, suggesting that the enzyme is encoded by pcpA. PcpA has low but significant sequence similarity to an unusual class of extradiol dioxygenases. On the basis of the sequence analysis, the Fe2+ and O2 dependence of the enzyme, and the characteristics of the product, the enzyme is proposed to be a 2,6-dichlorohydroquinone dioxygenase. The position of ring cleavage has not yet been identified.

  17. Kinetics of interaction between substrates/substrate analogs and benzoate 1,2-dioxygenase from benzoate-degrading Rhodococcus opacus 1CP.

    Science.gov (United States)

    Solyanikova, Inna P; Borzova, Oksana V; Emelyanova, Elena V

    2017-07-01

    Benzoate 1,2-dioxygenase (BDO) of Rhodococcus opacus 1CP, which carried out the initial attack on benzoate, was earlier shown to be the enzyme with a narrow substrate specificity. A kinetics of interaction between benzoate 1,2-dioxygenase and substituted benzoates was assessed taking into account the enlarged list of the type of inhibition and using whole cells grown on benzoate. The type of inhibition was determined and the constants of a reaction of BDO with benzoate in the presence of 2-chlorobenzoate (2CBA), 3,5-dichlorobenzoate (3,5DCBA), and 3-methylbenzoate (3MBA) were calculated. For 2CBA and 3MBA, the types of inhibition were classified as biparametrically disсoordinated inhibition and transient inhibition (from activation towards inhibition), respectively. The process of not widely recognized pseudoinhibition of a BDO reaction with benzoate by 3,5DCBA was assessed by the vector method for the representation of enzymatic reactions. Ki value was determined for 2CBA, 3MBA, and 3,5DCBA as 337.5, 870.3, and 14.7 μM, respectively.

  18. Searching iron sensors in plants by exploring the link among 2’-OG-dependent dioxygenases, the iron deficiency response and metabolic adjustments occurring under iron deficiency

    Directory of Open Access Journals (Sweden)

    GIANPIERO eVIGANI

    2013-05-01

    Full Text Available Knowledge accumulated on the regulation of iron (Fe homeostasis, its intracellular trafficking and transport across various cellular compartments and organs in plants; storage proteins, transporters and transcription factors involved in Fe metabolism have been analysed in detail in recent years. However, the key sensor(s of cellular plant Fe status triggering the long-distance shoot-root signalling and leading to the root Fe-deficiency responses is (are still unknown. Local Fe sensing is also a major task for roots, for adjusting the internal Fe requirements to external Fe availability: how such sensing is achieved and how it leads to metabolic adjustments in case of nutrient shortage, is mostly unknown. Two proteins belonging to the 2′-OG dependent dioxygenases family accumulate several folds in Fe-deficient Arabidopsis roots. Such proteins require Fe(II as enzymatic cofactor; one of their subgroups, the HIF-P4H (Hypoxia Inducible Factor- Prolyl 4-Hydroxylase, is an effective oxygen sensor in animal cells. We envisage here the possibility that some members of the 2′-OG dioxygenase family may be involved in the Fe-deficiency response and in the metabolic adjustments to Fe deficiency or even in sensing Fe, in plant cells.

  19. Ability of bacterial biphenyl dioxygenases from Burkholderia sp. LB400 and Comamonas testosteroni B-356 to catalyse oxygenation of ortho-hydroxychlorobiphenyls formed from PCBs by plants

    International Nuclear Information System (INIS)

    Francova, K.; Mackova, M.; Macek, T.; Sylvestre, M.

    2004-01-01

    Bacterial dioxygenases are useful in breakdown of PCB products associated with plants. - Capacity of enzymes of the biphenyl/chlorobiphenyl pathway, especially biphenyl dioxygenase (BPDO) of two polychlorinated biphenyls (PCB) degrading bacteria, Burkholderia sp. LB400 and Comamonas testosteroni B-356, to metabolize ortho-substituted hydroxybiphenyls was tested.,These compounds found among plant products of PCB metabolism, are carrying chlorine atoms on the hydroxyl-substituted ring. The abilities of His-tagged purified LB400 and B-356 BPDOs to catalyze the oxygenation of 2-hydroxy-3-chlorobiphenyl, 2-hydroxy-5-chlorobiphenyl and 2-hydroxy-3,5-dichlorobiphenyl were compared. Both enzyme preparations catalyzed the hydroxylation of the three chloro-hydroxybiphenyls on the non-substituted ring. Neither LB400 BPDO nor B-356 BPDO oxygenated the substituted ring of the ortho-hydroxylated biphenyl. The fact that metabolites generated by both enzymes were identical for all three hydroxychlorobiphenyls tested; exclude any other mode of attack of these compounds by LB400 BPDOs than the ortho-meta oxygenation

  20. Purification of Biotransformation Products of Cis-Isoflavan-4-ol by Biphenyl Dioxygenase of Pseudomonas pseudoalcaligenes KF707 Strain Expressed in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Tri Ratna Sulistiyani

    2013-04-01

    Full Text Available Isoflavone has multiple beneficial effects on human health, especially through its antioxidant and anticancer activities. The biotransformation of isoflavone using byphenyl dioxygenase could be performed to extend the diversity of flavonoids and to improve their biological and physiological properties. Biotransformation of two enantiomers (3R, 4R-cis-isoflavan-4-ol and (3S, 4S-cis-isoflavan-4-ol by E. coli JM109 (pJHF108 carrying a biphenyl dioxygenase gene from P. pseudoalcaligenesKF707 produced two products, designated as CM1 andCM2. The products had a retention time of 11.9 and 14.6 min, respectively, and the same absorption peaks at 204, 220, and 275 nm. CM1 and CM2 had [M-H2O+H]+ at m/z 225. Based on the molecular mass and hydrolysis products, we proposed that epoxidation occurred on cis-isoflavan-4-ol. Chloroform extraction instead of ethyl acetate extraction was performed to improve the stability of cismetabolites, CM1 and CM2.

  1. Safety, immune and clinical responses in metastatic melanoma patients vaccinated with a long peptide derived from indoleamine 2,3-dioxygenase in combination with ipilimumab

    DEFF Research Database (Denmark)

    Bjørn, Jon; Iversen, Trine Zeeberg; Nitschke, Nikolaj Juul

    2016-01-01

    BACKGROUND AIM: Indoleamine 2,3-dioxygenase (IDO) is an emerging new target in cancer therapy that can be targeted with active immunotherapy (e.g. through peptide vaccination). Furthermore, IDO has been identified as a key mechanism underlying resistance to treatment with the checkpoint blocking...... antibody ipilimumab (ipi). METHODS: Ten patients with metastatic melanoma participated in a phase I first-in-human clinical study assessing safety of combining ipi with a 21-mer synthetic peptide vaccine from IDO denoted IDOlong. Secondary and tertiary end points included vaccine and clinical response....... RESULTS: Treatment was generally safe and well tolerated. Vaccine related adverse reactions included grade I and II erythema, oedema and pruritus at the vaccination site, which were manageable with mild topical corticosteroids. One patient developed presumed ipi-induced colitis. It initially responded...

  2. Interferon-γ regulates the proliferation and differentiation of mesenchymal stem cells via activation of indoleamine 2,3 dioxygenase (IDO.

    Directory of Open Access Journals (Sweden)

    Juliana Croitoru-Lamoury

    Full Text Available The kynurenine pathway (KP of tryptophan metabolism is linked to antimicrobial activity and modulation of immune responses but its role in stem cell biology is unknown. We show that human and mouse mesenchymal and neural stem cells (MSCs and NSCs express the complete KP, including indoleamine 2,3 dioxygenase 1 (IDO and IDO2, that it is highly regulated by type I (IFN-β and II interferons (IFN-γ, and that its transcriptional modulation depends on the type of interferon, cell type and species. IFN-γ inhibited proliferation and altered human and mouse MSC neural, adipocytic and osteocytic differentiation via the activation of IDO. A functional KP present in MSCs, NSCs and perhaps other stem cell types offers novel therapeutic opportunities for optimisation of stem cell proliferation and differentiation.

  3. Remarkable Role of Indoleamine 2,3-Dioxygenase and Tryptophan Metabolites in Infectious Diseases: Potential Role in Macrophage-Mediated Inflammatory Diseases

    Directory of Open Access Journals (Sweden)

    Yuki Murakami

    2013-01-01

    Full Text Available Indoleamine 2,3-dioxygenase 1 (IDO1, the L-tryptophan-degrading enzyme, plays a key role in the immunomodulatory effects on several types of immune cells. Originally known for its regulatory function during pregnancy and chronic inflammation in tumorigenesis, the activity of IDO1 seems to modify the inflammatory state of infectious diseases. The pathophysiologic activity of L-tryptophan metabolites, kynurenines, is well recognized. Therefore, an understanding of the regulation of IDO1 and the subsequent biochemical reactions is essential for the design of therapeutic strategies in certain immune diseases. In this paper, current knowledge about the role of IDO1 and its metabolites during various infectious diseases is presented. Particularly, the regulation of type I interferons (IFNs production via IDO1 in virus infection is discussed. This paper offers insights into new therapeutic strategies in the modulation of viral infection and several immune-related disorders.

  4. Synthesis of 3-oxalinolenic acid and beta-oxidation-resistant 3-oxa-oxylipins.

    Science.gov (United States)

    Hamberg, Mats; Chechetkin, Ivan R; Grechkin, Alexander N; Ponce de León, Inés; Castresana, Carmen; Bannenberg, Gerard

    2006-05-01

    3-Oxalinolenic acid (3-oxa-9(Z),12(Z),15(Z)-octadecatrienoic acid or (6(Z),9(Z),12(Z)-pentadecatrienyloxy)acetic acid) was synthesized from 5(Z),8(Z),11(Z),14(Z),17(Z)-eicosapentaenoic acid by a sequence involving the C15 aldehyde 3(Z),6(Z),9(Z),12(Z)-pentadecatetraenal as a key intermediate. Conversion of the aldehyde by isomerization and two steps of reduction afforded 6(Z),9(Z),12(Z)-pentadecatrienol, which was coupled to bromoacetate to afford after purification by HPLC >99%-pure 3-oxalinolenic acid in 10-15% overall yield. 3-Oxalinolenic acid was efficiently oxygenated by soybean lipoxygenase-1 into 3-oxa-13(S)-hydroperoxy-9(Z),11(E),15(Z)-octadecatrienoic acid, and this hydroperoxide could be further converted chemically into 3-oxa-13(S)-hydroxy-9(Z),11 (E),15(Z)-octadecatrienoic acid and 3-oxa-13-oxo-9(Z),11 (E),15(Z)-octadecatrienoic acid. The 3-oxa-hydroperoxide also served as the substrate for the plant enzymes allene oxide synthase, divinyl ether synthase, and hydroperoxide lyase to produce 3-oxa-12-oxo-10,15(Z)-phytodienoic acid and other 3-oxa-oxylipins that were characterized by MS. 3-Oxalinolenic acid was not oxygenated by 9-lipoxygenase from tomato but was converted at a slow rate into 3-oxa-9(S)-hydroperoxy-10(E),12(Z),15(Z)-octadecatrienoic acid by recombinant maize 9-lipoxygenase. Recombinant alpha-dioxygenase-1 from Arabidopsis thaliana catalyzed the conversion of 3-oxalinolenic acid into a 2-hydroperoxide, which underwent spontaneous degradation into a mixture of 6,9,12-pentadecatrienol and 6,9,12-pentadecatrienyl formate. A novel alpha-dioxygenase from the moss Physcomitrella patens was cloned and expressed and was found to display the same activity with 3-oxalinolenic acid as Arabidopsis thaliana alpha-dioxygenase-1. Lipoxygenase-generated 3-oxa-oxylipins are resistant toward beta-oxidation and have the potential for displaying enhanced biological activity in situations where activity is limited by metabolic degradation.

  5. Genome-Wide Analysis of the Biosynthesis and Deactivation of Gibberellin-Dioxygenases Gene Family in Camellia sinensis (L. O. Kuntze

    Directory of Open Access Journals (Sweden)

    Cheng Pan

    2017-09-01

    Full Text Available Gibberellins (GAs, a class of diterpenoid phytohormones, play a key role in regulating diverse processes throughout the life cycle of plants. Bioactive GA levels are rapidly regulated by Gibberellin-dioxygenases (GAox, which are involved in the biosynthesis and deactivation of gibberellin. In this manuscript, a comprehensive genome-wide analysis was carried out to find all GAox in Camellia sinensis. For the first time in a tea plant, 14 CsGAox genes, containing two domains, DIOX_N (PF14226 and 2OG-FeII_Oxy, were identified (PF03171. These genes all belong to 2-oxoglutarate-dependent dioxygenases (2-ODD, including four CsGA20ox (EC: 1.14.11.12, three CsGA3ox (EC: 1.14.11.15, and seven CsGA2ox (EC: 1.14.11.13. According to the phylogenetic classification as in Arabidopsis, the CsGAox genes spanned five subgroups. Each CsGAox shows tissue-specific expression patterns, although these vary greatly. Some candidate genes, which may play an important role in response to external abiotic stresses, have been identified with regards to patterns, such as CsGA20ox2, CsGA3ox2, CsGA3ox3, CsGA2ox1, CsGA2ox2, and CsGA2ox4. The bioactive GA levels may be closely related to the GA20ox, GA3ox and GA2ox genes. In addition, the candidate genes could be used as marker genes for abiotic stress resistance breeding in tea plants.

  6. Enzymes Involved in the Aerobic Bacterial Degradation of N-Heteroaromatic Compounds: Molybdenum Hydroxylases and Ring-Opening 2,4-Dioxygenases

    Science.gov (United States)

    Fetzner, S.

    Many N-heteroaromatic compounds are utilized by micro-organisms as a source of carbon (and nitrogen) and energy. The aerobic bacterial degradation of these growth substrates frequently involves several hydroxylation steps and subsequent dioxygenolytic cleavage of (di)hydroxy-substituted heteroaromatic intermediates to aliphatic metabolites which finally are channeled into central metabolic pathways. As a rule, the initial bacterial hydroxylation of a N-heteroaromatic compound is catalyzed by a molybdenum hydroxylase, which uses a water molecule as source of the incorporated oxygen. The enzyme's redox-active centers - the active site molybdenum ion coordinated to a distinct pyranopterin cofactor, two different [2Fe2S] centers, and in most cases, flavin adenine dinucleotide - transfer electrons from the N-heterocyclic substrate to an electron acceptor, which for many molybdenum hydroxylases is still unknown. Ring-opening 2,4-dioxygenases involved in the bacterial degradation of quinaldine and 1H-4-oxoquinoline catalyze the cleavage of two carbon-carbon bonds with concomitant formation of carbon monoxide. Since they contain neither a metal center nor an organic cofactor, and since they do not show any sequence similarity to known oxygenases, these unique dioxygenases form a separate enzyme family. Quite surprisingly, however, they appear to be structurally and mechanistically related to enzymes of the α/β hydrolase fold superfamily. Microbial enzymes are a great resource for biotechnological applications. Microbial strains or their enzymes may be used for degradative (bioremediation) or synthetic (biotransformation) purposes. Modern bioremediation or biotransformation strategies may even involve microbial catalysts or strains designed by protein engineering or pathway engineering. Prerequisite for developing such modern tools of biotechnology is a comprehensive understanding of microbial metabolic pathways, of the structure and function of enzymes, and of the

  7. Nutritional Stress Induced by Tryptophan-Degrading Enzymes Results in ATF4-Dependent Reprogramming of the Amino Acid Transporter Profile in Tumor Cells.

    Science.gov (United States)

    Timosenko, Elina; Ghadbane, Hemza; Silk, Jonathan D; Shepherd, Dawn; Gileadi, Uzi; Howson, Lauren J; Laynes, Robert; Zhao, Qi; Strausberg, Robert L; Olsen, Lars R; Taylor, Stephen; Buffa, Francesca M; Boyd, Richard; Cerundolo, Vincenzo

    2016-11-01

    Tryptophan degradation is an immune escape strategy shared by many tumors. However, cancer cells' compensatory mechanisms remain unclear. We demonstrate here that a shortage of tryptophan caused by expression of indoleamine 2,3-dioxygenase (IDO) and tryptophan 2,3-dioxygenase (TDO) resulted in ATF4-dependent upregulation of several amino acid transporters, including SLC1A5 and its truncated isoforms, which in turn enhanced tryptophan and glutamine uptake. Importantly, SLC1A5 failed to be upregulated in resting human T cells kept under low tryptophan conditions but was enhanced upon cognate antigen T-cell receptor engagement. Our results highlight key differences in the ability of tumor and T cells to adapt to tryptophan starvation and provide important insights into the poor prognosis of tumors coexpressing IDO and SLC1A5. Cancer Res; 76(21); 6193-204. ©2016 AACR. ©2016 American Association for Cancer Research.

  8. A multi-enzymatic cascade reaction for the stereoselective production of γ-oxyfunctionalyzed amino acids

    Directory of Open Access Journals (Sweden)

    Junichi eEnoki

    2016-04-01

    Full Text Available A stereoselective three-enzyme cascade for synthesis of diasteromerically pure γ-oxyfunctionalized α-amino acids was developed. By coupling a dynamic kinetic resolution using an N-acylamino acid racemase and an L-selective aminoacylase from Geobacillus thermoglucosidasius with a stereoselective isoleucine dioxygenase from Bacillus thuringiensis, diastereomerically pure oxidized amino acids were produced from racemic N-acetylamino acids. The three enzymes differ in their optimal temperature and pH-spectra. Their different metal cofactor dependencies lead to inhibitory effects. Under optimized conditions, racemic N-acetylmethionine was quantitatively converted into L-methionine-(S-sulfoxide with 97% conversion and 95% de. The combination of these three different biocatalysts allows the direct synthesis of diastereopure oxyfunctionalized amino acids from inexpensive racemic starting material.

  9. Production of muconic acid in plants.

    Science.gov (United States)

    Eudes, Aymerick; Berthomieu, Roland; Hao, Zhangying; Zhao, Nanxia; Benites, Veronica Teixeira; Baidoo, Edward E K; Loqué, Dominique

    2018-03-01

    Muconic acid (MA) is a dicarboxylic acid used for the production of industrially relevant chemicals such as adipic acid, terephthalic acid, and caprolactam. Because the synthesis of these polymer precursors generates toxic intermediates by utilizing petroleum-derived chemicals and corrosive catalysts, the development of alternative strategies for the bio-based production of MA has garnered significant interest. Plants produce organic carbon skeletons by harvesting carbon dioxide and energy from the sun, and therefore represent advantageous hosts for engineered metabolic pathways towards the manufacturing of chemicals. In this work, we engineered Arabidopsis to demonstrate that plants can serve as green factories for the bio-manufacturing of MA. In particular, dual expression of plastid-targeted bacterial salicylate hydroxylase (NahG) and catechol 1,2-dioxygenase (CatA) resulted in the conversion of the endogenous salicylic acid (SA) pool into MA via catechol. Sequential increase of SA derived from the shikimate pathway was achieved by expressing plastid-targeted versions of bacterial salicylate synthase (Irp9) and feedback-resistant 3-deoxy-D-arabino-heptulosonate synthase (AroG). Introducing this SA over-producing strategy into engineered plants that co-express NahG and CatA resulted in a 50-fold increase in MA titers. Considering that MA was easily recovered from senesced plant biomass after harvest, we envision the phytoproduction of MA as a beneficial option to add value to bioenergy crops. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

  10. Benzene-free synthesis of adipic acid.

    Science.gov (United States)

    Niu, Wei; Draths, K M; Frost, J W

    2002-01-01

    Strains of Escherichia coli were constructed and evaluated that synthesized cis,cis-muconic acid from D-glucose under fed-batch fermentor conditions. Chemical hydrogenation of the cis,cis-muconic acid in the resulting fermentation broth has also been examined. Biocatalytic synthesis of adipic acid from glucose eliminates two environmental concerns characteristic of industrial adipic acid manufacture: use of carcinogenic benzene and benzene-derived chemicals as feedstocks and generation of nitrous oxide as a byproduct of a nitric acid catalyzed oxidation. While alternative catalytic syntheses that eliminate the use of nitric acid have been developed, most continue to rely on petroleum-derived benzene as the ultimate feedstock. In this study, E. coli WN1/pWN2.248 was developed that synthesized 36.8 g/L of cis,cis-muconic acid in 22% (mol/mol) yield from glucose after 48 h of culturing under fed-batch fermentor conditions. Optimization of microbial cis,cis-muconic acid synthesis required expression of three enzymes not typically found in E. coli. Two copies of the Klebsiella pneumoniae aroZ gene encoding DHS dehydratase were inserted into the E. coli chromosome, while the K. pneumoniae aroY gene encoding PCA decarboxylase and the Acinetobacter calcoaceticus catA gene encoding catechol 1,2-dioxygenase were expressed from an extrachromosomal plasmid. After fed-batch culturing of WN1/pWN2.248 was complete, the cells were removed from the broth, which was treated with activated charcoal and subsequently filtered to remove soluble protein. Hydrogenation of the resulting solution with 10% Pt on carbon (5% mol/mol) at 3400 kPa of H2 pressure for 2.5 h at ambient temperature afforded a 97% (mol/mol) conversion of cis,cis-muconic acid into adipic acid.

  11. Synthesis of 5-hydroxyectoine from ectoine: crystal structure of the non-heme iron(II and 2-oxoglutarate-dependent dioxygenase EctD.

    Directory of Open Access Journals (Sweden)

    Klaus Reuter

    2010-05-01

    Full Text Available As a response to high osmolality, many microorganisms synthesize various types of compatible solutes. These organic osmolytes aid in offsetting the detrimental effects of low water activity on cell physiology. One of these compatible solutes is ectoine. A sub-group of the ectoine producer's enzymatically convert this tetrahydropyrimidine into a hydroxylated derivative, 5-hydroxyectoine. This compound also functions as an effective osmostress protectant and compatible solute but it possesses properties that differ in several aspects from those of ectoine. The enzyme responsible for ectoine hydroxylation (EctD is a member of the non-heme iron(II-containing and 2-oxoglutarate-dependent dioxygenases (EC 1.14.11. These enzymes couple the decarboxylation of 2-oxoglutarate with the formation of a high-energy ferryl-oxo intermediate to catalyze the oxidation of the bound organic substrate. We report here the crystal structure of the ectoine hydroxylase EctD from the moderate halophile Virgibacillus salexigens in complex with Fe(3+ at a resolution of 1.85 A. Like other non-heme iron(II and 2-oxoglutarate dependent dioxygenases, the core of the EctD structure consists of a double-stranded beta-helix forming the main portion of the active-site of the enzyme. The positioning of the iron ligand in the active-site of EctD is mediated by an evolutionarily conserved 2-His-1-carboxylate iron-binding motif. The side chains of the three residues forming this iron-binding site protrude into a deep cavity in the EctD structure that also harbours the 2-oxoglutarate co-substrate-binding site. Database searches revealed a widespread occurrence of EctD-type proteins in members of the Bacteria but only in a single representative of the Archaea, the marine crenarchaeon Nitrosopumilus maritimus. The EctD crystal structure reported here can serve as a template to guide further biochemical and structural studies of this biotechnologically interesting enzyme family.

  12. 2-Oxoglutarate: linking TCA cycle function with amino acid, glucosinolate, flavonoid, alkaloid, and gibberellin biosynthesis.

    Science.gov (United States)

    Araújo, Wagner L; Martins, Auxiliadora O; Fernie, Alisdair R; Tohge, Takayuki

    2014-01-01

    The tricarboxylic acid (TCA) cycle intermediate 2-oxoglutarate (2-OG) is used as an obligatory substrate in a range of oxidative reactions catalyzed by 2-OG-dependent dioxygenases. These enzymes are widespread in nature being involved in several important biochemical processes. We have recently demonstrated that tomato plants in which the TCA cycle enzyme 2-OG dehydrogenase (2-ODD) was antisense inhibited were characterized by early senescence and modified fruit ripening associated with differences in the levels of bioactive gibberellin (GA). Accordingly, there is now compelling evidence that the TCA cycle plays an important role in modulating the rate of flux from 2-OG to amino acid metabolism. Here we discuss recent advances in the biochemistry and molecular biology of 2-OG metabolism occurring in different biological systems indicating the importance of 2-OG and 2-OG dependent dioxygenases not only in glucosinolate, flavonoid and alkaloid metabolism but also in GA and amino acid metabolism. We additionally summarize recent findings regarding the impact of modification of 2-OG metabolism on biosynthetic pathways involving 2-ODDs.

  13. 2-Oxoglutarate: linking TCA cycle function with amino acid, glucosinolate, flavonoid, alkaloid and gibberellin biosynthesis

    Directory of Open Access Journals (Sweden)

    Wagner L. Araújo

    2014-10-01

    Full Text Available The tricarboxylic acid (TCA cycle intermediate 2-oxoglutarate (2-OG is used as an obligatory substrate in a range of oxidative reactions catalyzed by 2-OG-dependent dioxygenases. These enzymes are widespread in nature being involved in several important biochemical processes. We have recently demonstrated that tomato plants in which the TCA cycle enzyme 2-OG dehydrogenase (2-ODD was antisense inhibited were characterized by early senescence and modified fruit ripening associated with differences in the levels of bioactive gibberellin (GA. Accordingly, there is now compelling evidence that the TCA cycle plays an important role in modulating the rate of flux from 2-OG to amino acid metabolism. Here we discuss recent advances in the biochemistry and molecular biology of 2-OG metabolism occurring in different biological systems indicating the importance of 2-OG and 2-OG dependent dioxygenases not only in glucosinolate, flavonoid and alkaloid metabolism but also in GA and amino acid metabolism. We additionally summarize recent findings regarding the impact of modification of 2-OG metabolism on biosynthetic pathways involving 2-ODDs.

  14. Tryptamine and dimethyltryptamine inhibit indoleamine 2,3 dioxygenase and increase the tumor-reactive effect of peripheral blood mononuclear cells.

    Science.gov (United States)

    Tourino, Melissa Cavalheiro; de Oliveira, Edson Mendes; Bellé, Luziane Potrich; Knebel, Franciele Hinterholz; Albuquerque, Renata Chaves; Dörr, Felipe Augusto; Okada, Sabrina Sayori; Migliorini, Silene; Soares, Irene Silva; Campa, Ana

    2013-07-01

    Indoleamine 2,3-dioxygenase (IDO) is an interferon-γ (IFN-γ)-induced tryptophan-degrading enzyme, producing kynurenine (KYN) that participates in the mechanism of tumor immune tolerance. Thus, IDO inhibition has been considered a strategy for anticancer therapy. The aim of this study was to identify whether the metabolites originated from the competitive routes of tryptophan metabolism, such as the serotonergic or N, N-dimethyltryptamine (DMT) pathways, have inhibitory effects on recombinant human IDO (rhIDO) activity. Serotonin and melatonin had no effect; on the other hand, tryptamine (TRY) and DMT modulated the activity of rhIDO as classical non-competitive inhibitors, with Ki values of 156 and 506 μM, respectively. This inhibitory effect was also observed on constitutively expressed or IFN-γ-induced IDO in the A172 human glioma cell line. TRY and DMT increased the cytotoxic activity of peripheral blood mononuclear cells (PBMCs) in co-culture assays. We conclude that the IDO inhibition by TRY and DMT contributed to a more effective tumor-reactive response by the PBMCs. Copyright © 2013 John Wiley & Sons, Ltd.

  15. The potato carotenoid cleavage dioxygenase 4 catalyzes a single cleavage of β-ionone ring-containing carotenes and non-epoxidated xanthophylls

    KAUST Repository

    Bruno, Mark

    2015-04-01

    Down-regulation of the potato carotenoid cleavage dioxygenase 4 (StCCD4) transcript level led to tubers with altered morphology and sprouting activity, which also accumulated higher levels of violaxanthin and lutein leading to elevated carotenoid amounts. This phenotype indicates a role of this enzyme in tuber development, which may be exerted by a cleavage product. In this work, we investigated the enzymatic activity of StCCD4, by expressing the corresponding cDNA in carotenoid accumulating Escherichia coli strains and by performing in vitro assays with heterologously expressed enzyme. StCCD4 catalyzed the cleavage of all-. trans-β-carotene at the C9\\'-C10\\' double bond, leading to β-ionone and all-. trans-β-apo-10\\'-carotenal, both in vivo and in vitro. The enzyme also cleaved β,β-cryptoxanthin, zeaxanthin and lutein either at the C9\\'-C10\\' or the C9-C10 double bond in vitro. In contrast, we did not observe any conversion of violaxanthin and only traces of activity with 9-. cis-β-carotene, which led to 9-. cis-β-apo-10\\'-carotenal. Our data indicate that all-. trans-β-carotene is the likely substrate of StCCD4 in planta, and that this carotene may be precursor of an unknown compound involved in tuber development.

  16. Kinetic and spectroscopic investigation of CoII, NiII, and N-oxalylglycine inhibition of the FeII/α-ketoglutarate dioxygenase, TauD

    International Nuclear Information System (INIS)

    Kalliri, Efthalia; Grzyska, Piotr K.; Hausinger, Robert P.

    2005-01-01

    Co II , Ni II , and N-oxalylglycine (NOG) are well-known inhibitors of Fe II /α-ketoglutarate (αKG)-dependent hydroxylases, but few studies describe their kinetics and no spectroscopic investigations have been reported. Using taurine/αKG dioxygenase (TauD) as a paradigm for this enzyme family, time-dependent inhibition assays showed that Co II and Ni II follow slow-binding inhibition kinetics. Whereas Ni II -substituted TauD was non-chromophoric, spectroscopic studies of the Co II -substituted enzyme revealed a six-coordinate site (protein alone or with αKG) that became five-coordinate upon taurine addition. The Co II spectrum was not perturbed by a series of anions or oxidants, suggesting the Co II is inaccessible and could be used to stabilize the protein. NOG competed weakly (K i ∼ 290 μM) with αKG for binding to TauD, with the increased electron density of NOG yielding electronic transitions for NOG-Fe II -TauD and taurine-NOG-Fe II -TauD at 380 nm (ε 38 90-105 M -1 cm -1 ). The spectra of the NOG-bound TauD species did not change significantly upon oxygen exposure, arguing against the formation of an oxygen-bound state mimicking an early intermediate in catalysis

  17. Brief Report: Proteasomal Indoleamine 2,3-Dioxygenase Degradation Reduces the Immunosuppressive Potential of Clinical Grade-Mesenchymal Stromal Cells Undergoing Replicative Senescence.

    Science.gov (United States)

    Loisel, Séverine; Dulong, Joëlle; Ménard, Cédric; Renoud, Marie-Laure; Meziere, Nadine; Isabelle, Bezier; Latour, Maëlle; Bescher, Nadège; Pedeux, Rémy; Bertheuil, Nicolas; Flecher, Erwan; Sensebé, Luc; Tarte, Karin

    2017-05-01

    Owing to their immunosuppressive properties, mesenchymal stromal cells (MSCs) obtained from bone marrow (BM-MSCs) or adipose tissue (ASCs) are considered a promising tool for cell therapy. However, important issues should be considered to ensure the reproducible production of efficient and safe clinical-grade MSCs. In particular, high expansion rate, associated with progressive senescence, was recently proposed as one of the parameters that could alter MSC functionality. In this study, we directly address the consequences of replicative senescence on BM-MSC and ASC immunomodulatory properties. We demonstrate that MSCs produced according to GMP procedures inhibit less efficiently T-cell, but not Natural Killer (NK)- and B-cell, proliferation after reaching senescence. Senescence-related loss-of-function is associated with a decreased indoleamine 2,3-dioxygenase (IDO) activity in response to inflammatory stimuli. In particular, although STAT-1-dependent IDO expression is transcriptionally induced at a similar level in senescent and nonsenescent MSCs, IDO protein is specifically degraded by the proteasome in senescent ASCs and BM-MSCs, a process that could be reversed by the MG132 proteasome inhibitor. These data encourage the use of appropriate quality controls focusing on immunosuppressive mechanisms before translating clinical-grade MSCs in the clinic. Stem Cells 2017;35:1431-1436. © 2017 AlphaMed Press.

  18. Chemo-Immunotherapy: Role of Indoleamine 2,3-Dioxygenase in Defining Immunogenic Versus Tolerogenic Cell Death in the Tumor Microenvironment.

    Science.gov (United States)

    Johnson, Theodore S; Mcgaha, Tracy; Munn, David H

    2017-01-01

    In certain settings, chemotherapy can trigger an immunogenic form of tumor cell death. More often, however, tumor cell death after chemotherapy is not immunogenic, and may be actively tolerizing. However, even in these settings the dying tumor cells may be much more immunogenic than previously recognized, if key suppressive immune checkpoints such as indoleamine 2,3-dioxygenase (IDO) can be blocked. This is an important question, because a robust immune response to dying tumor cells could potentially augment the efficacy of conventional chemotherapy, or enhance the strength and duration of response to other immunologic therapies. Recent findings using preclinical models of self-tolerance and autoimmunity suggest that IDO and related downstream pathways may play a fundamental role in the decision between tolerance versus immune activation in response to dying cells. Thus, in the period of tumor cell death following chemotherapy or immunotherapy, the presence of IDO may help dictate the choice between dominant immunosuppression versus inflammation, antigen cross-presentation, and epitope spreading. The IDO pathway thus differs from other checkpoint-blockade strategies, in that it affects early immune responses, at the level of inflammation, activation of antigen-presenting cells, and initial cross-presentation of tumor antigens. This "up-stream" position may make IDO a potent target for therapeutic inhibition.

  19. Enhanced tolerance and remediation to mixed contaminates of PCBs and 2,4-DCP by transgenic alfalfa plants expressing the 2,3-dihydroxybiphenyl-1,2-dioxygenase.

    Science.gov (United States)

    Wang, Yan; Ren, Hejun; Pan, Hongyu; Liu, Jinliang; Zhang, Lanying

    2015-04-09

    Polychlorinated biphenyls (PCBs) and 2,4-dichlorophenol (2,4-DCP) generally led to mixed contamination of soils as a result of commercial and agricultural activities. Their accumulation in the environment poses great risks to human and animal health. Therefore, the effective strategies for disposal of these pollutants are urgently needed. In this study, genetic engineering to enhance PCBs/2,4-DCP phytoremediation is a focus. We cloned the 2,3-dihydroxybiphenyl-1,2-dioxygenase (BphC.B) from a soil metagenomic library, which is the key enzyme of aerobic catabolism of a variety of aromatic compounds, and then it was expressed in alfalfa driven by CaMV 35S promoter using Agrobacterium-mediated transformation. Transgenic line BB11 was selected out through PCR, Western blot analysis and enzyme activity assays. Its disposal and tolerance to both PCBs and 2,4-DCP were examined. The tolerance capability of transgenic line BB11 towards complex contaminants of PCBs/2,4-DCP significantly increased compared with non-transgenic plants. Strong dissipation of PCBs and high removal efficiency of 2,4-DCP were exhibited in a short time. It was confirmed expressing BphC.B would be a feasible strategy to help achieving phytoremediation in mixed contaminated soils with PCBs and 2,4-DCP. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Tomato carotenoid cleavage dioxygenases 1A and 1B: Relaxed double bond specificity leads to a plenitude of dialdehydes, mono-apocarotenoids and isoprenoid volatiles

    KAUST Repository

    Ilg, Andrea

    2014-06-25

    The biosynthetic processes leading to many of the isoprenoid volatiles released by tomato fruits are still unknown, though previous reports suggested a clear correlation with the carotenoids contained within the fruit. In this study, we investigated the activity of the tomato (Solanum lycopersicum) carotenoid cleavage dioxygenase (SlCCD1B), which is highly expressed in fruits, and of its homolog SlCCD1A. Using in vitro assays performed with purified recombinant enzymes and by analyzing products formed by the two enzymes in carotene-accumulating Escherichia coli strains, we demonstrate that SlCCD1A and, to a larger extent, SlCCD1B, have a very relaxed specificity for both substrate and cleavage site, mediating the oxidative cleavage of cis- and all-. trans-carotenoids as well as of different apocarotenoids at many more double bonds than previously reported. This activity gives rise to a plenitude of volatiles, mono-apocarotenoids and dialdehyde products, including cis-pseudoionone, neral, geranial, and farnesylacetone. Our results provide a direct evidence for a carotenoid origin of these compounds and point to CCD1s as the enzymes catalyzing the formation of the vast majority of tomato isoprenoid volatiles, many of which are aroma constituents. © 2014 The Authors.

  1. Increased activity of indoleamine 2,3-dioxygenase in serum from acutely infected dengue patients linked to gamma interferon antiviral function

    Science.gov (United States)

    Becerra, Aniuska; Warke, Rajas V.; Xhaja, Kris; Evans, Barbara; Evans, James; Martin, Katherine; de Bosch, Norma; Rothman, Alan L.; Bosch, Irene

    2009-01-01

    The depletion of l-tryptophan (L-Trp) has been associated with the inhibition of growth of micro-organisms and also has profound effects on T cell proliferation and immune tolerance. The enzyme indoleamine 2,3-dioxygenase (IDO) catalyses the rate-limiting step in the catabolic pathway of L-Trp. Gene expression analysis has shown upregulation of genes involved in L-Trp catabolism in in vitro models of dengue virus (DENV) infection. To understand the role of IDO during DENV infection, we measured IDO activity in sera from control and DENV-infected patients. We found increased IDO activity, lower levels of L-Trp and higher levels of l-kynurenine in sera from DENV-infected patients during the febrile days of the disease compared with patients with other febrile illnesses and healthy donors. Furthermore, we confirmed upregulation of IDO mRNA expression in response to DENV infection in vitro, using a dendritic cell (DC) model of DENV infection. We found that the antiviral effect of gamma interferon (IFN-γ) in DENV-infected DCs in vitro was partially dependent on IDO activity. Our results demonstrate that IDO plays an important role in the antiviral effect of IFN-γ against DENV infection in vitro and suggest that it has a role in the immune response to DENV infections in vivo. PMID:19264674

  2. Effects of Various Phytochemicals on Indoleamine 2,3-Dioxygenase 1 Activity: Galanal Is a Novel, Competitive Inhibitor of the Enzyme

    Science.gov (United States)

    Yamamoto, Rie; Yamamoto, Yasuko; Imai, Shinjiro; Fukutomi, Ryuta; Ozawa, Yoshio; Abe, Masako; Matuo, Yushi; Saito, Kuniaki

    2014-01-01

    Indoleamine 2,3-dioxygenase (IDO) 1, that catalyzes the first and rate-limiting step in the degradation of L-tryptophan, has an important immunomodulatory function. The activity of IDO1 increases in various inflammatory diseases, including tumors, autoimmune diseases, and different kinds of inflammation. We evaluated the suppressive effect of plant extracts or phytochemicals on IDO1 induction and activity; sixteen kinds of plants extracts and fourteen kinds of phytochemicals were examined. As a result, the methanol extracts of Myoga flower buds, which are traditional Japanese foods, and labdane-type diterpene galanal derived from Myoga flowers significantly suppressed IDO1 activity. The Lineweaver-Burk plot analysis indicated that galanal is a competitive inhibitor. Galanal attenuated L-kynurenine formation with an IC50 value of 7.7 µM in the assay system using recombinant human IDO1, and an IC50 value of 45 nM in the cell-based assay. Further, mechanistic analysis revealed that galanal interfered with the transcriptional function of the nuclear factor-κB and the interferon-γ signaling pathway. These effects of galanal are important for immune response. Because the inhibitory effect of galanal on IDO1 activity was stronger than that of 1-methyl tryptophan, a tryptophan analog, galanal may have great potential as the novel drug for various immune-related diseases. PMID:24533148

  3. Indoleamine 2,3-dioxygenase (IDO) is frequently expressed in stromal cells of Hodgkin lymphoma and is associated with adverse clinical features: a retrospective cohort study

    International Nuclear Information System (INIS)

    Choe, Ji-Young; Yun, Ji Yun; Jeon, Yoon Kyoung; Kim, Se Hoon; Park, Gyeongsin; Huh, Joo Ryoung; Oh, Sohee; Kim, Ji Eun

    2014-01-01

    Regulation of tumor microenvironment is closely involved in the prognosis of Hodgkin lymphoma (HL). Indoleamine 2,3-dioxygenase (IDO) is an enzyme acting as immune modulator through suppression of T-cell immunity. This study aims to investigate role of IDO in the microenvironment of HL. A total of 121 cases of HL were enrolled to do immunohistochemistry for IDO, CD163, CD68, CD4, CD8, and FoxP3. Positivity was evaluated from area fractions or numbers of positive cells using automated image analyzer. Correlations between IDO expression and various cellular infiltrates and clinicopathologic parameters were examined and survival analyses were performed. IDO was expressed in histiocytes, dendritic cells and some endothelial cells with variable degrees, but not in tumor cells. IDO positive cells were more frequently found in mixed cellularity type than other histologic types, and in cases with EBV+, high Ann Arbor stages, B symptoms, and high IPS (all p < 0.05). High IDO expression was associated with inferior survival (p < 0.001) and reflects an independent prognostic factor in nodular sclerosis HL. This is the first study suggesting that IDO is the principle immunomodulator and is involved to adverse clinical outcomes of HL

  4. Effects of Tranilast on the Urinary Excretion of Kynurenic and Quinolinic Acid under Conditions of L Tryptophan Loading

    Directory of Open Access Journals (Sweden)

    Rowland R. Noakes

    2013-01-01

    Full Text Available The pathogenesis of morphea and other cutaneous sclerosing disorders remain poorly understood. Although they are considered to be autoimmune disorders, abnormal tryptophan metabolism may be involved. Current therapy is directed to supressing the autoimmune response. Demonstration of a therapeutic response to manipulation of the kynurenine pathway would both support a role for abnormal tryptophan metabolism and offer additional targets for therapy. Tranilast is a 3-hydroxyanthranilic acid derivative known to target the kynurenine pathway. The aim of this study was to see if tranilast lowered the urinary excretion of the kynurenine metabolites kynurenic and quinolinic acid under condition of L tryptophan loading in a volunteer. Mean baseline value for kynurenic acid and quinolinic acid were 1.1 and 2.1 mmol/mol creatinine, respectively. This rose to 5.6 and 3.8 mmol/mol creatinine respectively under conditions of L tryptophan loading 2 grams daily. Adding 1 g of tranilast daily lowered the values to 2.0 and 2.9 mmol/mol creatinine, respectively. These data suggest that tranilast acts as a competitive inhibitor of either indoleamine 2, 3-dioxygenase (IDO, tryptophan 2, 3 di-oxygenase (TDO or both. As it involved only 1 subject, the results may not be representative of the larger population and must be considered preliminary.

  5. Studies on Nitrobenzene Metabolism by a Comamonas sp. Strain JS7651

    National Research Council Canada - National Science Library

    Gibson, David

    2000-01-01

    .... The nitrobenzene dioxygenase enzyme system shares high amino acid homology with other identified nitroarene dioxygenase enzymes, in particular the 2-nitrotoluene dioxygenase system from Pseudomonas sp. strain JS42...

  6. Long-lasting disease stabilization in the absence of toxicity in metastatic lung cancer patients vaccinated with an epitope derived from indoleamine 2,3 dioxygenase.

    Science.gov (United States)

    Iversen, Trine Zeeberg; Engell-Noerregaard, Lotte; Ellebaek, Eva; Andersen, Rikke; Larsen, Stine Kiaer; Bjoern, Jon; Zeyher, Claus; Gouttefangeas, Cécile; Thomsen, Birthe Moerk; Holm, Bente; Thor Straten, Per; Mellemgaard, Anders; Andersen, Mads Hald; Svane, Inge Marie

    2014-01-01

    To investigate targeting of indoleamine 2,3 dioxygenase (IDO) enzyme using a synthetic peptide vaccine administered to patients with metastatic non-small cell lung cancer (NSCLC). In a clinical phase I study, we treated 15 HLA-A2-positive patients with stage III-IV NSCLC in disease stabilization after standard chemotherapy. Patients were treated with imiquimod ointment and subcutaneous vaccinations (100 μg IDO5 peptide, sequence ALLEIASCL, formulated in 900 μL Montanide). Primary endpoint was toxicity. Clinical benefit and immunity were assessed as secondary endpoints. No severe toxicity was observed. One patient developed a partial response (PR) after one year of vaccine treatment, whereas long-lasting stable disease (SD) ≥ 8.5 months was demonstrated in another six patients. The median overall survival (OS) was 25.9 months. Patients demonstrated significant improved OS (P = 0.03) when compared with the group of patients excluded because of HLA-A2 negativity. IDO-specific CD8(+) T-cell immunity was demonstrated by IFN-γ Elispot and Tetramer staining. Fluorescence-activated cell sorting analyses demonstrated a significant reduction of the Treg population (P = 0.03) after the sixth vaccine (2.5 months) compared with pretreatment levels. Furthermore, expression of IDO was detected in nine of ten tumor biopsies by immunohistochemistry. High-performance liquid chromatography analyses of kynurenine/tryptophan (Kyn/Trp) ratio in sera were performed. In long-term analyses of two clinical responding patients, the ratio of Kyn/Trp remained stable. The vaccine was well tolerated with no severe toxicity occurring. A median OS of 25.9 months was demonstrated and long-lasting PR+SD was seen in 47% of the patients.

  7. Involvement of NpdA, a Putative 2-Nitropropane Dioxygenase, in the T3SS Expression and Full Virulence inRalstonia solanacearumOE1-1.

    Science.gov (United States)

    Zhang, Weiqi; Li, Jing; Tang, Yu; Chen, Kai; Shi, Xiaojun; Ohnishi, Kouhei; Zhang, Yong

    2017-01-01

    Previously, we isolated several genes that potentially affected the expression of type III secretion system (T3SS) in Ralstonia solanacearum OE1-1. Here, we focused on the rsp0316 , which encodes a putative 2-nitropropane dioxygenase (hereafter designated NpdA). The deletion of npdA substantially reduced the T3SS expression and virulence in OE1-1, and the complementation with functional NpdA could completely restore its reduced T3SS expression and virulence to that of wild type. The NpdA was highly conserved among diverse R. solanacearum species and the NpdA-dependent expression of T3SS was not specific to OE1-1 strain, but not the virulence. The NpdA was important for the T3SS expression in planta , while it was not required for the bacterial growth in planta . Moreover, the NpdA was not required for the elicitation of hypersensitive response (HR) of R. solanacearum strains in tobacco leaves. The T3SS in R. solanacearum is directly controlled by the AraC-type transcriptional regulator HrpB and regulated by a complex regulation network. The NpdA affected the T3SS expression mediated with HrpB but through some novel pathway. All these results from genetic studies demonstrate that NpdA is a novel factor for the T3SS expression in diverse R. solanacearum species in medium, but specifically for the T3SS expression in strain OE1-1 in planta . And the NpdA-dependent expression of T3SS in planta plays an important role in pathogenicity of R. solanacearum OE1-1 in host plants.

  8. Lipopolysaccharide-induced brain activation of the indoleamine 2,3-dioxygenase and depressive-like behavior are impaired in a mouse model of metabolic syndrome.

    Science.gov (United States)

    Dinel, Anne-Laure; André, Caroline; Aubert, Agnès; Ferreira, Guillaume; Layé, Sophie; Castanon, Nathalie

    2014-02-01

    Although peripheral low-grade inflammation has been associated with a high incidence of mood symptoms in patients with metabolic syndrome (MetS), much less is known about the potential involvement of brain activation of cytokines in that context. Recently we showed in a mouse model of MetS, namely the db/db mice, an enhanced hippocampal inflammation associated with increased anxiety-like behavior (Dinel et al., 2011). However, depressive-like behavior was not affected in db/db mice. Based on the strong association between depressive-like behavior and cytokine-induced brain activation of indoleamine 2,3-dioxygenase (IDO), the enzyme that metabolizes tryptophan along the kynurenine pathway, these results may suggest an impairment of brain IDO activation in db/db mice. To test this hypothesis, we measured the ability of db/db mice and their healthy db/+ littermates to enhance brain IDO activity and depressive-like behavior after a systemic immune challenge with lipopolysaccharide (LPS). Here we show that LPS (5 μg/mouse) significantly increased depressive-like behavior (increased immobility time in a forced-swim test, FST) 24h after treatment in db/+ mice, but not in db/db mice. Interestingly, db/db mice also displayed after LPS treatment blunted increase of brain kynurenine/tryptophan ratio compared to their db/+ counterparts, despite enhanced induction of hippocampal cytokine expression (interleukin-1β, tumor necrosis factor-α). Moreover, this was associated with an impaired effect of LPS on hippocampal expression of the brain-derived neurotrophic factor (BDNF) that contributes to mood regulation, including under inflammatory conditions. Collectively, these data indicate that the rise in brain tryptophan catabolism and depressive-like behavior induced by innate immune system activation is impaired in db/db mice. These findings could have relevance in improving the management and treatment of inflammation-related complications in MetS. Copyright © 2013 Elsevier

  9. Inhibition of Indoleamine 2,3-Dioxygenase Activity by Levo-1-Methyl Tryptophan Blocks Gamma Interferon-Induced Chlamydia trachomatis Persistence in Human Epithelial Cells ▿

    Science.gov (United States)

    Ibana, Joyce A.; Belland, Robert J.; Zea, Arnold H.; Schust, Danny J.; Nagamatsu, Takeshi; AbdelRahman, Yasser M.; Tate, David J.; Beatty, Wandy L.; Aiyar, Ashok A.; Quayle, Alison J.

    2011-01-01

    Gamma interferon (IFN-γ) induces expression of the tryptophan-catabolizing enzyme indoleamine 2,3-dioxygenase (IDO1) in human epithelial cells, the permissive cells for the obligate intracellular bacterium Chlamydia trachomatis. IDO1 depletes tryptophan by catabolizing it to kynurenine with consequences for C. trachomatis, which is a tryptophan auxotroph. In vitro studies reveal that tryptophan depletion can result in the formation of persistent (viable but noncultivable) chlamydial forms. Here, we tested the effects of the IDO1 inhibitor, levo-1-methyl-tryptophan (L-1MT), on IFN-γ-induced C. trachomatis persistence. We found that addition of 0.2 mM L-1MT to IFN-γ-exposed infected HeLa cell cultures restricted IDO1 activity at the mid-stage (20 h postinfection [hpi]) of the chlamydial developmental cycle. This delayed tryptophan depletion until the late stage (38 hpi) of the cycle. Parallel morphological and gene expression studies indicated a consequence of the delay was a block in the induction of C. trachomatis persistence by IFN-γ. Furthermore, L-1MT addition allowed C. trachomatis to undergo secondary differentiation, albeit with limited productive multiplication of the bacterium. IFN-γ-induced persistent infections in epithelial cells have been previously reported to be more resistant to doxycycline than normal productive infections in vitro. Pertinent to this observation, we found that L-1MT significantly improved the efficacy of doxycycline in clearing persistent C. trachomatis forms. It has been postulated that persistent forms of C. trachomatis may contribute to chronic chlamydial disease. Our findings suggest that IDO1 inhibitors such as L-1MT might provide a novel means to investigate, and potentially target, persistent chlamydial forms, particularly in conjunction with conventional therapeutics. PMID:21911470

  10. Implication of Tryptophan 2,3-Dioxygenase and its Novel Variants in the Hippocampus and Cerebellum During the Developing and Adult Brain

    Directory of Open Access Journals (Sweden)

    Masaaki Kanai

    2010-07-01

    Full Text Available Tryptophan 2,3-dioxygenase (TDO is a first and rate-limiting enzyme for the kynurenine pathway of tryptophan metabolism. Using Tdo-/-mice, we have recently shown that TDO plays a pivotal role in systemic tryptophan metabolism and brain serotonin synthesis as well as emotional status and adult neurogenesis. However, the expression of TDO in the brain has not yet been well characterized, in contrast to its predominant expression in the liver. To further examine the possible role of local TDO in the brain, we quantified the levels of tdo mRNA in various nervous tissues, using Northern blot and quantitative real-time RT-PCR. Higher levels of tdo mRNA expression were detected in the cerebellum and hippocampus. We also identified two novel variants of the tdo gene, termed tdo variant1 and variant2, in the brain. Similar to the known TDO form (TDO full-form, tetramer formation and enzymatic activity were obtained when these variant forms were expressed in vitro. While quantitative real-time RT-PCR revealed that the tissue distribution of these variants was similar to that of tdo full-form, the expression patterns of these variants during early postnatal development in the hippocampus and cerebellum differed. Our findings indicate that in addition to hepatic TDO, TDO and its variants in the brain might function in the developing and adult nervous system. Given the previously reported associations of tdo gene polymorphisms in the patients with autism and Tourette syndrome, the expression of TDO in the brain suggests the possible influence of TDO on psychiatric status. Potential functions of TDOs in the cerebellum, hippocampus and cerebral cortex under physiological and pathological conditions are discussed.

  11. Homogentisate 1-2-Dioxygenase Downregulation in the Chronic Persistence of Pseudomonas aeruginosa Australian Epidemic Strain-1 in the CF Lung.

    Directory of Open Access Journals (Sweden)

    Christopher J Harmer

    Full Text Available Some Pseudomonas aeruginosa strains including Australian Epidemic Strain-1 (AES-1 or AUS-01 cause persistent chronic infection in cystic fibrosis (CF patients, with greater morbidity and mortality. Factors conferring persistence are largely unknown. Previously we analysed the transcriptomes of AES-1 grown in Luria broth, nematode growth medium for Caenorhabditis elegans assay (both aerobic and artificial sputum medium (mainly hypoxic. Transcriptional comparisons included chronic AES-1 strains against PAO1 and acute AES-1 (AES-1R against its chronic isogen (AES-1M, isolated 10.5 years apart from a CF patient and not eradicated in the meantime. Prominent amongst genes downregulated in AES-1M in all comparisons was homogentisate-1-2-dioxygenase (hmgA; an oxygen-dependent gene known to be mutationally deactivated in many chronic infection strains of P. aeruginosa. To investigate if hmgA downregulation and deactivation gave similar virulence persistence profiles, a hmgA mutant made in UCBPP-PA14 utilising RedS-recombinase and AES-1M were assessed in the C. elegans virulence assay, and the C57BL/6 mouse for pulmonary colonisation and TNF-α response. In C. elegans, hmgA deactivation resulted in significantly increased PA14 virulence while hmgA downregulation reduced AES-1M virulence. AES-1M was significantly more persistent in mouse lung and showed a significant increase in TNF-α (p<0.0001, sustained even with no detectable bacteria. PA14ΔhmgA did not show increased TNF-α. This study suggests that hmgA may have a role in P. aeruginosa persistence in chronic infection and the results provide a starting point for clarifying the role of hmgA in chronic AES-1.

  12. Indoleamine 2,3-dioxygenase mediates inhibition of virus-specific CD8(+) T cell proliferation by human mesenchymal stromal cells.

    Science.gov (United States)

    Hong, Jian; Hueckelhoven, Angela; Wang, Lei; Schmitt, Anita; Wuchter, Patrick; Tabarkiewicz, Jacek; Kleist, Christian; Bieback, Karen; Ho, Anthony D; Schmitt, Michael

    2016-05-01

    Mesenchymal stromal cells (MSCs) exert broad immunomodulatory functions. We recently demonstrated a strong suppressive effect of MSCs on virus-specific CD8(+) T-cell proliferation. Here, we further explored the underlying mechanism. The role of indoleamine 2,3-dioxygenase (IDO) in inhibition of virus-specific CD8(+) T-cell proliferation by human MSCs was investigated using a mixed lymphocyte peptide culture assay, IDO intracellular staining and IDO inhibition through 1-methyl-DL-tryptophan (1-MT). Moreover, the influence of the number of passages and the seeding density of MSCs on their IDO expression and immunosuppressive ability were investigated. MSCs with low IDO expression exhibited a reduced suppressive effect on both allo-antigen- and cytomegalovirus (CMV)-specific CD8(+) T-cell proliferation. 1-MT could partially abrogate the suppressive effect. MSCs inhibited CMV-specific CD8(+) T-cell proliferation regardless of the number of passages and the seeding density. IDO expression of MSCs was not significantly affected by the number of passages or the seeding density. In addition, the interferon (IFN)-γ level in the culture system was crucial for MSCs to inhibit the proliferation of CMV-specific CD8(+) T cells. MSCs inhibit virus-specific CD8(+) T-cell proliferation through IFN-γ-induced IDO activity, resolving current conflicting reports on this issue and indicating the potential need for prophylaxis and surveillance of virus infection in patients treated with MSCs. In addition, our study makes a contribution to the development of MSC potency assay for clinical use. Copyright © 2016 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

  13. Catechol 2,3-dioxygenase and other meta-cleavage catabolic pathway genes in the 'anaerobic' termite gut spirochete Treponema primitia.

    Science.gov (United States)

    Lucey, Kaitlyn S; Leadbetter, Jared R

    2014-03-01

    Microorganisms have evolved a spectacular diversity of metabolisms, some of which allow them to overcome environmental constraints, utilize abundant but inaccessible resources and drive nutrient cycling in various ecosystems. The termite hindgut microbial community is optimized to metabolize wood, and in recent years, the in situ physiological and ecological functions of community members have been researched. Spirochetes are abundant in the termite gut, and herein, putative aromatic meta-cleavage pathway genes typical of aerobic pseudomonads were located in genomes of homoacetogenic termite hindgut 'anaerobes', Treponema primitia str. ZAS-1 and ZAS-2. Phylogenetic analyses suggest the T. primitia catechol 2,3-dioxygenase and several other essential meta-pathway genes were acquired from an α-proteobacterium in the distant past to augment several genes T. primitia acquired from anaerobic firmicutes that do not directly catabolize aromatics but can contribute to the final pathway steps. Further, transcripts for each meta-pathway gene were expressed in strictly anaerobic cultures of T. primitia str. ZAS-2 indicative of constitutive pathway expression. Also, the addition of catechol + O(2) to T. primitia liquid cultures resulted in the transient accumulation of trace amounts of the yellow ring cleavage product, hydroxymuconic semialdehyde. This is the first evidence of aromatic ring cleavage in the phylum (division) Spirochetes. Results also support a possible role for T. primitia in termite hindgut O(2) /lignin aromatic monomer metabolism. Potential O(2) -dependent yet nonrespiratory microbial metabolisms have heretofore been overlooked and warrant further investigation. These metabolisms could describe the degradation of plant-derived and other aromatics in microoxic environments and contribute significantly to carbon turnover. © 2013 John Wiley & Sons Ltd.

  14. Enhanced enzymatic degradation of tryptophan by indoleamine 2,3-dioxygenase contributes to the tryptophan-deficient state seen after major trauma.

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    Pellegrin, Katharina; Neurauter, Gabriele; Wirleitner, Barbara; Fleming, Arthur W; Peterson, Verlyn M; Fuchs, Dietmar

    2005-03-01

    Decreased lymphocyte proliferation, lymphopenia, immunodepression, and opportunistic infections are common after major trauma. Early alimentation in these patients corrects lymphopenia, enhances immunity, and reduces the incidence of infections, but the underlying mechanisms are poorly understood. Tryptophan is essential for the production and function of rapidly proliferating cells such as lymphocytes. Tryptophan is enzymatically degraded by indoleamine 2,3-dioxygenase (IDO), whose activity is solely dependent on expression of interferon-gamma (IFN-gamma). Because increased expression of IFN-gamma has been reported in trauma patients, we investigated whether enhanced IDO-mediated tryptophan degradation is associated with lymphopenia and poor outcomes after major trauma. The incidence of bacteremic sepsis (BS), adult respiratory distress syndrome (ARDS), multiple organ dysfunction/failure syndromes (MODS/MOF), and death was prospectively documented in 22 trauma patients with a mean ISS of 24.9 +/- 2.2. Sequential blood samples were obtained from admission through postinjury day 10. Five patients developed BS, three of whom developed ARDS; two of the three ARDS patients developed MOF and died on day 10. Trauma patients had significantly lower tryptophan levels (days 1-10), higher kynurenine:tryptophan ratios (days 1-2), and fewer lymphocytes (days 1-4) than healthy volunteers (P < 0.05). Although patients with poor outcomes (i.e., BS, ARDS, MOF, and death) had significantly lower tryptophan levels and greater lymphopenia on several days after injury, the sample size was too small to draw any definitive conclusions. These data indicate that decreased plasma tryptophan levels and lymphopenia typically occur after major trauma. A concomitant increase in kynurenine suggests that the observed tryptophan deficiency is caused, in part, by IDO-mediated tryptophan degradation.

  15. Indoleamine 2,3-dioxygenase controls fungal loads and immunity in Paracoccidioidomicosis but is more important to susceptible than resistant hosts.

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    Araújo, Eliseu F; Loures, Flávio V; Bazan, Silvia B; Feriotti, Claudia; Pina, Adriana; Schanoski, Alessandra S; Costa, Tânia A; Calich, Vera L G

    2014-11-01

    Paracoccidioidomycosis, a primary fungal infection restricted to Latin America, is acquired by inhalation of fungal particles. The immunoregulatory mechanisms that control the severe and mild forms of paracoccidioidomycosis are still unclear. Indoleamine 2,3-dioxygenase (IDO), an IFN-γ induced enzyme that catalyzes tryptophan metabolism, can control host-pathogen interaction by inhibiting pathogen growth, T cell immunity and tissue inflammation. In this study, we investigated the role of IDO in pulmonary paracoccidioidomycosis of susceptible and resistant mice. IDO was blocked by 1-methyl-dl-tryptophan (1MT), and fungal infection studied in vitro and in vivo. Paracoccidioides brasiliensis infection was more severe in 1MT treated than untreated macrophages of resistant and susceptible mice, concurrently with decreased production of kynurenines and IDO mRNA. Similar results were observed in the pulmonary infection. Independent of the host genetic pattern, IDO inhibition reduced fungal clearance but enhanced T cell immunity. The early IDO inhibition resulted in increased differentiation of dendritic and Th17 cells, accompanied by reduced responses of Th1 and Treg cells. Despite these equivalent biological effects, only in susceptible mice the temporary IDO blockade caused sustained fungal growth, increased tissue pathology and mortality rates. In contrast, resistant mice were able to recover the transitory IDO blockade by the late control of fungal burdens without enhanced tissue pathology. Our studies demonstrate for the first time that in pulmonary paracoccidioidomycosis, IDO is an important immunoregulatory enzyme that promotes fungal clearance and inhibits T cell immunity and inflammation, with prominent importance to susceptible hosts. In fact, only in the susceptible background IDO inhibition resulted in uncontrolled tissue pathology and mortality rates. Our findings open new perspectives to understand the immunopathology of paracoccidioidomycosis, and suggest

  16. Indoleamine 2,3-dioxygenase controls fungal loads and immunity in Paracoccidioidomicosis but is more important to susceptible than resistant hosts.

    Directory of Open Access Journals (Sweden)

    Eliseu F Araújo

    2014-11-01

    Full Text Available Paracoccidioidomycosis, a primary fungal infection restricted to Latin America, is acquired by inhalation of fungal particles. The immunoregulatory mechanisms that control the severe and mild forms of paracoccidioidomycosis are still unclear. Indoleamine 2,3-dioxygenase (IDO, an IFN-γ induced enzyme that catalyzes tryptophan metabolism, can control host-pathogen interaction by inhibiting pathogen growth, T cell immunity and tissue inflammation.In this study, we investigated the role of IDO in pulmonary paracoccidioidomycosis of susceptible and resistant mice. IDO was blocked by 1-methyl-dl-tryptophan (1MT, and fungal infection studied in vitro and in vivo. Paracoccidioides brasiliensis infection was more severe in 1MT treated than untreated macrophages of resistant and susceptible mice, concurrently with decreased production of kynurenines and IDO mRNA. Similar results were observed in the pulmonary infection. Independent of the host genetic pattern, IDO inhibition reduced fungal clearance but enhanced T cell immunity. The early IDO inhibition resulted in increased differentiation of dendritic and Th17 cells, accompanied by reduced responses of Th1 and Treg cells. Despite these equivalent biological effects, only in susceptible mice the temporary IDO blockade caused sustained fungal growth, increased tissue pathology and mortality rates. In contrast, resistant mice were able to recover the transitory IDO blockade by the late control of fungal burdens without enhanced tissue pathology.Our studies demonstrate for the first time that in pulmonary paracoccidioidomycosis, IDO is an important immunoregulatory enzyme that promotes fungal clearance and inhibits T cell immunity and inflammation, with prominent importance to susceptible hosts. In fact, only in the susceptible background IDO inhibition resulted in uncontrolled tissue pathology and mortality rates. Our findings open new perspectives to understand the immunopathology of

  17. A dioxygenase of Pleurotus sapidus transforms (+)-valencene regio-specifically to (+)-nootkatone via a stereo-specific allylic hydroperoxidation.

    Science.gov (United States)

    Krügener, Sven; Krings, Ulrich; Zorn, Holger; Berger, Ralf G

    2010-01-01

    A selective and highly efficient allylic oxidation of the sesquiterpene (+)-valencene to the grapefruit flavour compound (+)-nootkatone was achieved with lyophilisate of the edible mushroom Pleurotus sapidus. The catalytic reaction sequence was elucidated through the identification of intermediate, (+)-valencene derived hydroperoxides. A specific staining of hydroperoxides allowed the semi-preparative isolation of two secondary (+)-valencene hydroperoxides, 6(R)-Isopropenyl-4(R),4a(S)-dimethyl-2,3,4,4a,5,6,7,8-octahydro-naphthalen-4(S)-yl-hydroperoxide and 6(R)-Isopropenyl-4(R),4a(S)-dimethyl-2,3,4,4a,5,6,7,8-octahydro-naphthalen-2(R)-yl-hydroperoxide. Chemical reduction of the biotransformation products yielded a tertiary alcohol identified as 2(R)-Isopropenyl-8(R),8a(S)-dimethyl-1,3,4,7,8,8a-hexahydro-2H-naphthalen-4a(R)-ol. This suggested a lipoxygenase-type oxidation of (+)-valencene via secondary and tertiary hydroperoxides and confirmed homology data of the key enzyme obtained previously from amino acid sequencing.

  18. Mechanism of antiinflammatory actions of curcumine and boswellic acids.

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    Ammon, H P; Safayhi, H; Mack, T; Sabieraj, J

    1993-03-01

    Curcumine from Curcuma longa and the gum resin of Boswellia serrata, which were demonstrated to act as anti-inflammatories in in vivo animal models, were studied in a set of in vitro experiments in order to elucidate the mechanism of their beneficial effects. Curcumine inhibited the 5-lipoxygenase activity in rat peritoneal neutrophils as well as the 12-lipoxygenase and the cyclooxygenase activities in human platelets. In a cell free peroxidation system curcumine exerted strong antioxidative activity. Thus, its effects on the dioxygenases are probably due to its reducing capacity. Boswellic acids were isolated from the gum resin of Boswellia serrata and identified as the active principles. Boswellic acids inhibited the leukotriene synthesis via 5-lipoxygenase, but did not affect the 12-lipoxygenase and the cyclooxygenase activities. Additionally, boswellic acids did not impair the peroxidation of arachidonic acid by iron and ascorbate. The data suggest that boswellic acids are specific, non-redox inhibitors of leukotriene synthesis either interacting directly with 5-lipoxygenase or blocking its translocation.

  19. Indoleamine 2,3-dioxygenase in endometrial cancer: a targetable mechanism of immune resistance in mismatch repair-deficient and intact endometrial carcinomas.

    Science.gov (United States)

    Mills, Anne; Zadeh, Sara; Sloan, Emily; Chinn, Zachary; Modesitt, Susan C; Ring, Kari L

    2018-03-20

    Mismatch repair-deficient endometrial carcinomas are optimal candidates for immunotherapy given their high neoantigen loads, robust lymphoid infiltrates, and frequent PD-L1 expression. However, co-opting the PD-1/PD-L1 pathway is just one mechanism that tumors can utilize to evade host immunity. Another immune modulatory molecule that has been demonstrated in endometrial carcinoma is indoleamine 2,3-dioxygenase (IDO). We herein evaluate IDO expression in 60 endometrial carcinomas and assess results in relation to PD-L1 and mismatch repair status. IDO immunohistochemistry was performed on 60 endometrial carcinomas (20 Lynch syndrome (LS)-associated, 20 MLH1 promoter hypermethylated, and 20 mismatch repair-intact). Eight-five percent of endometrial carcinomas showed IDO tumor staining in >1% of cells. Twenty-five percent were positive in >25% of tumor cells and only 7% exceeded 50% staining. Mismatch repair-deficient cancers were more likely than mismatch repair-intact cancers to be >25% IDO-positive (35% vs. 5% p = 0.024). Differences were amplified when Lynch syndrome-associated cases were evaluated in isolation (50% Lynch syndrome-associated vs. 10% mismatch repair-intact and MLH1-hypermethylated, p = 0.001). Of the four cases showing >50% staining, three were Lynch syndrome-associated and one was MLH1-hypermethylated; no mismatch repair-intact cases had >50% staining. Forty-three percent of IDO-positive tumors were also positive for PD-L1, whereas only two cases showed tumoral PD-L1 in the absence of IDO. In summary, IDO expression is prevalent in endometrial carcinomas and diffuse staining is significantly more common in mismatch repair-deficient cancers, particularly Lynch syndrome-associated cases. Given that the majority of PD-L1 positive cancers also express IDO, synergistic combination therapy with anti-IDO and anti-PD1/PD-L1 may be relevant in this tumor type. Furthermore, anti-IDO therapy may be an option for a small subset of mismatch repair

  20. Indoleamine 2,3-Dioxygenase (IDO) Enzyme Links Innate Immunity and Altered T-Cell Differentiation in Non-ST Segment Elevation Acute Coronary Syndrome.

    Science.gov (United States)

    Zara, Chiara; Severino, Anna; Flego, Davide; Ruggio, Aureliano; Pedicino, Daniela; Giglio, Ada Francesca; Trotta, Francesco; Lucci, Claudia; D'Amario, Domenico; Vinci, Ramona; Pisano, Eugenia; La Rosa, Giulio; Biasucci, Luigi Marzio; Crea, Filippo; Liuzzo, Giovanna

    2017-12-26

    Atherosclerosis is a chronic inflammatory disease characterized by a complex interplay between innate and adaptive immunity. Dendritic cells (DCs) play a key role in T-cell activation and regulation by promoting a tolerogenic environment through the expression of the immunosuppressive enzyme indoleamine 2,3-dioxygenase (IDO), an intracellular enzyme involved in tryptophan catabolism. IDO expression and activity was analyzed in monocytes derived DCs (MDDCs) from non-ST segment elevation myocardial infarction (NSTEMI) patients, stable angina (SA) patients and healthy controls (HC) by real-time quantitative polymerase chain reaction (RT-qPCR) before and after in vitro maturation with lipopolysaccharide (LPS). The amount of tryptophan catabolite; kynurenine; was evaluated in the culture supernatants of mature-MDDCs by ELISA assay. Autologous mixed lymphocyte reaction (MLR) between mature-MDDCs and naïve T-cells was carried out to study the differentiation towards T-helper 1 (Th1) and induced regulatory T-cells (iTreg). Analysis of IDO mRNA transcripts in mature-MDDCs revealed a significant reduction in cells isolated from NSTEMI (625.0 ± 128.2; mean ± SEM) as compared with those from SA (958.5 ± 218.3; p = 0.041) and from HC (1183.6 ± 231.6; p = 0.034). Furthermore; the concentration of kynurenine was lower in NSTEMI patients (2.78 ± 0.2) and SA (2.98 ± 0.25) as compared with HC (5.1 ± 0.69 ng/mL; p = 0.002 and p = 0.016; respectively). When IDO-competent mature-MDDCs were co-cultured with allogeneic naïve T-cells, the ratio between the percentage of generated Th1 and iTreg was higher in NSTEMI (4.4 ± 2.9) than in SA (1.8 ± 0.6; p = 0.056) and HC (0.9 ± 0.3; p = 0.008). In NSTEMI, the tolerogenic mechanism of the immune response related to IDO production by activated MDDCs is altered, supporting their role in T-cell dysregulation.

  1. Indoleamine 2,3-Dioxygenase (IDO Enzyme Links Innate Immunity and Altered T-Cell Differentiation in Non-ST Segment Elevation Acute Coronary Syndrome

    Directory of Open Access Journals (Sweden)

    Chiara Zara

    2017-12-01

    Full Text Available Atherosclerosis is a chronic inflammatory disease characterized by a complex interplay between innate and adaptive immunity. Dendritic cells (DCs play a key role in T-cell activation and regulation by promoting a tolerogenic environment through the expression of the immunosuppressive enzyme indoleamine 2,3-dioxygenase (IDO, an intracellular enzyme involved in tryptophan catabolism. IDO expression and activity was analyzed in monocytes derived DCs (MDDCs from non-ST segment elevation myocardial infarction (NSTEMI patients, stable angina (SA patients and healthy controls (HC by real-time quantitative polymerase chain reaction (RT-qPCR before and after in vitro maturation with lipopolysaccharide (LPS. The amount of tryptophan catabolite; kynurenine; was evaluated in the culture supernatants of mature-MDDCs by ELISA assay. Autologous mixed lymphocyte reaction (MLR between mature-MDDCs and naïve T-cells was carried out to study the differentiation towards T-helper 1 (Th1 and induced regulatory T-cells (iTreg. Analysis of IDO mRNA transcripts in mature-MDDCs revealed a significant reduction in cells isolated from NSTEMI (625.0 ± 128.2; mean ± SEM as compared with those from SA (958.5 ± 218.3; p = 0.041 and from HC (1183.6 ± 231.6; p = 0.034. Furthermore; the concentration of kynurenine was lower in NSTEMI patients (2.78 ± 0.2 and SA (2.98 ± 0.25 as compared with HC (5.1 ± 0.69 ng/mL; p = 0.002 and p = 0.016; respectively. When IDO-competent mature-MDDCs were co-cultured with allogeneic naïve T-cells, the ratio between the percentage of generated Th1 and iTreg was higher in NSTEMI (4.4 ± 2.9 than in SA (1.8 ± 0.6; p = 0.056 and HC (0.9 ± 0.3; p = 0.008. In NSTEMI, the tolerogenic mechanism of the immune response related to IDO production by activated MDDCs is altered, supporting their role in T-cell dysregulation.

  2. Electron Transport in a Dioxygenase-Ferredoxin Complex: Long Range Charge Coupling between the Rieske and Non-Heme Iron Center.

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    Wayne K Dawson

    Full Text Available Dioxygenase (dOx utilizes stereospecific oxidation on aromatic molecules; consequently, dOx has potential applications in bioremediation and stereospecific oxidation synthesis. The reactive components of dOx comprise a Rieske structure Cys2[2Fe-2S]His2 and a non-heme reactive oxygen center (ROC. Between the Rieske structure and the ROC, a universally conserved Asp residue appears to bridge the two structures forming a Rieske-Asp-ROC triad, where the Asp is known to be essential for electron transfer processes. The Rieske and ROC share hydrogen bonds with Asp through their His ligands; suggesting an ideal network for electron transfer via the carboxyl side chain of Asp. Associated with the dOx is an itinerant charge carrying protein Ferredoxin (Fdx. Depending on the specific cognate, Fdx may also possess either the Rieske structure or a related structure known as 4-Cys-[2Fe-2S] (4-Cys. In this study, we extensively explore, at different levels of theory, the behavior of the individual components (Rieske and ROC and their interaction together via the Asp using a variety of density function methods, basis sets, and a method known as Generalized Ionic Fragment Approach (GIFA that permits setting up spin configurations manually. We also report results on the 4-Cys structure for comparison. The individual optimized structures are compared with observed spectroscopic data from the Rieske, 4-Cys and ROC structures (where information is available. The separate pieces are then combined together into a large Rieske-Asp-ROC (donor/bridge/acceptor complex to estimate the overall coupling between individual components, based on changes to the partial charges. The results suggest that the partial charges are significantly altered when Asp bridges the Rieske and the ROC; hence, long range coupling through hydrogen bonding effects via the intercalated Asp bridge can drastically affect the partial charge distributions compared to the individual isolated

  3. Preparation and evaluation of L- and D-5-[18F]fluorotryptophan as PET imaging probes for indoleamine and tryptophan 2,3-dioxygenases.

    Science.gov (United States)

    Tang, Tang; Gill, Herman S; Ogasawara, Annie; Tinianow, Jeff N; Vanderbilt, Alexander N; Williams, Simon-Peter; Hatzivassiliou, Georgia; White, Sharla; Sandoval, Wendy; DeMent, Kevin; Wong, Mengling; Marik, Jan

    2017-08-01

    Indoleamine and tryptophan 2,3-dioxygenases (IDO1 and TDO2) are pyrrolases catalyzing the oxidative cleavage of the 2,3-double bond of L-tryptophan in kynurenine pathway. In the tumor microenvironment, their increased activity prevents normal immune function, i.e. tumor cell recognition and elimination by cytotoxic T-cells. Consequently, inhibition of the kynurenine pathway may enhance the activity of cancer immunotherapeutics by reversing immune dysfunction. We sought to investigate the properties of radiolabeled 5-[ 18 F]fluorotryptophan with respect to its ability for measuring IDO1 and TDO2 activity by positron emission tomography (PET). L-5-[ 18 F]fluorotryptophan and D-5-[ 18 F]fluorotryptophan were synthesized by Cu(I) catalyzed [ 18 F]fluorodeboronylation of Boc/tBu protected precursors in moderate yields (1.5±0.6%) sufficient for pre-clinical studies. The specific activity of the product was 407-740GBq/μmol, radiochemical purity >99% and enantiomeric excess 90-99%. Enzymatic assay confirmed that L-5-fluorotryptophan is an IDO1 and TDO2 substrate whereas the D-isomer is not. In-vitro cell uptake experiments using CT26 cells with doxycycline-induced overexpression of human-IDO1 and human-TDO2 revealed an elevated cell uptake of L-5-[ 18 F]fluorotryptophan upon induction of IDO1 or TDO2 enzymes compared to baseline; however, the uptake was observed only in the presence of low L-tryptophan levels in media. PET imaging experiments performed using tumor bearing mouse models expressing IDO1 at various levels (CT26, CT26-hIDO1, 17082A, 17095A) showed tumor uptake of the tracer elevated up to 8%ID/g; however, the observed tumor uptake could not be attributed to IDO1 activity in the tumor tissue. The metabolism of L- and D- isomers was markedly different in vivo, the D-isomer was excreted by a combination of hepatobiliary and renal routes, the L-isomer underwent extensive metabolism to [ 18 F]fluoride. The observed in vivo tumor uptake of the tracer could not be

  4. Induced nitric oxide synthase (iNOS and indoleamine 2,3-dioxygenase (IDO detection in circulating monocyte subsets from Brazilian patients with Dengue-4 virus

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    Luciana Gomes Fialho

    2017-06-01

    Full Text Available Among viral diseases transmitted by mosquitoes, dengue is characterized by its rapid dispersion around the world. Dengue severity is associated to a cytokine “storm” leading to vascular hemorrhagic manifestations, plasma leakage and shock, but also producing viral clearance. Macrophage/monocyte activation occurs during infection. Monocyte lineage cells are among those that allow virus replication. We investigated circulating human monocyte subsets - classical CD14+CD16− and non-classical CD14+CD16+ - during DENV-4 infection in patients. Intracellular inducible nitric oxide synthase (iNOS and indoleamine 2,3–dioxygenase (IDO were detected in both monocyte subsets. Circulating CD14+CD16+ monocyte frequency is mildly increased during DENV-4 infection. INOS is more intensely detected in CD14+CD16− than in CD16+ monocytes and IDO in CD14+CD16+. DENV-4 patients show increase in NO, TNF-α, IFN-y, IP-10/CXL10, IL-10 and MCP-1/CCL2 plasma levels when compared to healthy individuals. The classical monocyte subset, CD14+CD16− was shown to be inversely correlated with IL-10 and IP-10/CXCL10 levels, while the non-classical CD14+CD16+ is positively correlated with IL-10 cytokine. TNF-α, IL-10 cytokines and IP-10/CXL10 chemokine are positively correlated with the CD14+iNOS+ monocyte population. Both CD14+ cells - CD16−iNOS+ and CD16+iNOS+ subsets - presented positive correlation with IL-10, IP-10/CXL10 and MCP-1/CCL2, besides TNF-α associated with CD16−iNOS+ cells. CD14+CD16−IDO+and CD16+IDO+ populations correlated positively with IL-10. Furthermore, CD16−IDO+ monocyte subset also presented a positive correlation with TNF-α and IP-10/CXCL10. According to these data, we considered that iNOS and IDO are activated in monocyte CD16− and CD16+ subsets, likely exerting both antiviral effects and modulating exacerbated immunological responses during dengue fever.

  5. Diet-induced obesity progressively alters cognition, anxiety-like behavior and lipopolysaccharide-induced depressive-like behavior: focus on brain indoleamine 2,3-dioxygenase activation.

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    André, Caroline; Dinel, Anne-Laure; Ferreira, Guillaume; Layé, Sophie; Castanon, Nathalie

    2014-10-01

    Obesity is associated with a high prevalence of mood symptoms and cognitive dysfunctions that emerges as significant risk factors for important health complications such as cardiovascular diseases and type 2 diabetes. It is therefore important to identify the dynamic of development and the pathophysiological mechanisms underlying these neuropsychiatric symptoms. Obesity is also associated with peripheral low-grade inflammation and increased susceptibility to immune-mediated diseases. Excessive production of proinflammatory cytokines and the resulting activation of the brain tryptophan catabolizing enzyme indoleamine 2,3-dioxygenase (IDO) have been shown to promote neurobehavioral complications, particularly depression. In that context, questions arise about the impact of diet-induced obesity on the onset of neuropsychiatric alterations and the increased susceptibility to immune-mediated diseases displayed by obese patients, particularly through brain IDO activation. To answer these questions, we used C57Bl/6 mice exposed to standard diet or western diet (WD; consisting of palatable energy-dense food) since weaning and for 20 weeks. We then measured inflammatory and behavioral responses to a systemic immune challenge with lipopolysaccharide (LPS) in experimental conditions known to alter cognitive and emotional behaviors independently of any motor impairment. We first showed that in absence of LPS, 9 weeks of WD is sufficient to impair spatial recognition memory (in the Y-maze). On the other hand, 18 weeks of WD increased anxiety-like behavior (in the elevated plus-maze), but did not affect depressive-like behavior (in the tail-suspension and forced-swim tests). However, 20 weeks of WD altered LPS-induced depressive-like behavior compared to LPS-treated lean mice and exacerbated hippocampal and hypothalamic proinflammatory cytokine expression and brain IDO activation. Taken together, these results show that WD exposure alters cognition and anxiety in unstimulated

  6. Betalain production is possible in anthocyanin-producing plant species given the presence of DOPA-dioxygenase and L-DOPA.

    Science.gov (United States)

    Harris, Nilangani N; Javellana, John; Davies, Kevin M; Lewis, David H; Jameson, Paula E; Deroles, Simon C; Calcott, Kate E; Gould, Kevin S; Schwinn, Kathy E

    2012-03-12

    Carotenoids and anthocyanins are the predominant non-chlorophyll pigments in plants. However, certain families within the order Caryophyllales produce another class of pigments, the betalains, instead of anthocyanins. The occurrence of betalains and anthocyanins is mutually exclusive. Betalains are divided into two classes, the betaxanthins and betacyanins, which produce yellow to orange or violet colours, respectively. In this article we show betalain production in species that normally produce anthocyanins, through a combination of genetic modification and substrate feeding. The biolistic introduction of DNA constructs for transient overexpression of two different dihydroxyphenylalanine (DOPA) dioxygenases (DODs), and feeding of DOD substrate (L-DOPA), was sufficient to induce betalain production in cell cultures of Solanum tuberosum (potato) and petals of Antirrhinum majus. HPLC analysis showed both betaxanthins and betacyanins were produced. Multi-cell foci with yellow, orange and/or red colours occurred, with either a fungal DOD (from Amanita muscaria) or a plant DOD (from Portulaca grandiflora), and the yellow/orange foci showed green autofluorescence characteristic of betaxanthins. Stably transformed Arabidopsis thaliana (arabidopsis) lines containing 35S: AmDOD produced yellow colouration in flowers and orange-red colouration in seedlings when fed L-DOPA. These tissues also showed green autofluorescence. HPLC analysis of the transgenic seedlings fed L-DOPA confirmed betaxanthin production. The fact that the introduction of DOD along with a supply of its substrate (L-DOPA) was sufficient to induce betacyanin production reveals the presence of a background enzyme, possibly a tyrosinase, that can convert L-DOPA to cyclo-DOPA (or dopaxanthin to betacyanin) in at least some anthocyanin-producing plants. The plants also demonstrate that betalains can accumulate in anthocyanin-producing species. Thus, introduction of a DOD and an enzyme capable of converting

  7. Betalain production is possible in anthocyanin-producing plant species given the presence of DOPA-dioxygenase and L-DOPA

    Directory of Open Access Journals (Sweden)

    Harris Nilangani N

    2012-03-01

    Full Text Available Abstract Background Carotenoids and anthocyanins are the predominant non-chlorophyll pigments in plants. However, certain families within the order Caryophyllales produce another class of pigments, the betalains, instead of anthocyanins. The occurrence of betalains and anthocyanins is mutually exclusive. Betalains are divided into two classes, the betaxanthins and betacyanins, which produce yellow to orange or violet colours, respectively. In this article we show betalain production in species that normally produce anthocyanins, through a combination of genetic modification and substrate feeding. Results The biolistic introduction of DNA constructs for transient overexpression of two different dihydroxyphenylalanine (DOPA dioxygenases (DODs, and feeding of DOD substrate (L-DOPA, was sufficient to induce betalain production in cell cultures of Solanum tuberosum (potato and petals of Antirrhinum majus. HPLC analysis showed both betaxanthins and betacyanins were produced. Multi-cell foci with yellow, orange and/or red colours occurred, with either a fungal DOD (from Amanita muscaria or a plant DOD (from Portulaca grandiflora, and the yellow/orange foci showed green autofluorescence characteristic of betaxanthins. Stably transformed Arabidopsis thaliana (arabidopsis lines containing 35S: AmDOD produced yellow colouration in flowers and orange-red colouration in seedlings when fed L-DOPA. These tissues also showed green autofluorescence. HPLC analysis of the transgenic seedlings fed L-DOPA confirmed betaxanthin production. Conclusions The fact that the introduction of DOD along with a supply of its substrate (L-DOPA was sufficient to induce betacyanin production reveals the presence of a background enzyme, possibly a tyrosinase, that can convert L-DOPA to cyclo-DOPA (or dopaxanthin to betacyanin in at least some anthocyanin-producing plants. The plants also demonstrate that betalains can accumulate in anthocyanin-producing species. Thus, introduction

  8. α-Ketol linolenic acid (KODA) application affects endogenous abscisic acid, jasmonic acid and aromatic volatiles in grapes infected by a pathogen (Glomerella cingulata).

    Science.gov (United States)

    Wang, Shanshan; Saito, Takanori; Ohkawa, Katsuya; Ohara, Hitoshi; Shishido, Masahiro; Ikeura, Hiromi; Takagi, Kazuteru; Ogawa, Shigeyuki; Yokoyama, Mineyuki; Kondo, Satoru

    2016-03-15

    Effects of α-ketol linolenic acid (KODA) application on endogenous abscisic acid (ABA), jasmonic acid (JA), and aromatic volatiles were investigated in 'Kyoho' grapes (Vitis labrusca×Vitis vinifera) infected by a pathogen (Glomerella cingulata). The expressions of 9-cis-epoxycarotenoid dioxygenase (VvNCED1), ABA 8'-hydroxylase (VvCYP707A1), lipoxygenase (VvLOX), and allene oxide synthase (VvAOS) were also examined. The grape berries were dipped in 0.1mM KODA solution before inoculation with the pathogen and stored at 25°C for 12 days. The development of infection was significantly suppressed upon KODA treatment. Endogenous ABA, JA and phaseic acid (PA) were induced in inoculated berries. KODA application before inoculation increased endogenous ABA, PA and JA through the activation of VvNCED1, VvCYP707A1 and VvAOS genes, respectively. In addition, terpenes, methyl salicylate (Me-SA) and C6-aldehydes such as (E)-2-hexenal and cis-3-hexenal associated with fungal resistance also increased in KODA-treated berries during storage. These results suggest that the synergistic effect of JA, ABA, and some aromatic volatiles induced by KODA application may provide resistance to pathogen infection in grape berries. Copyright © 2016 Elsevier GmbH. All rights reserved.

  9. Degradation of a model pollutant ferulic acid by the endophytic fungus Phomopsis liquidambari.

    Science.gov (United States)

    Xie, Xing-Guang; Dai, Chuan-Chao

    2015-03-01

    Biodegradation of ferulic acid, by an endophytic fungus called Phomopsis liquidambari was investigated in this study. This strain can use ferulic acid as the sole carbon for growth. Both in mineral salt medium and in soil, more than 97% of added ferulic acid was degraded within 48 h. The metabolites were identified and quantified using GC-MS and HPLC-MS. Ferulic acid was first decarboxylated to 4-vinyl guaiacol and then oxidized to vanillin and vanillic acid, followed by demethylation to protocatechuic acid, which was further degraded through the β-ketoadipate pathway. During degradation, ferulic acid decarboxylase, laccase and protocatechuate 3,4-dioxygenase activities and their gene transcription levels were significantly affected by the variation of substrate and product concentrations. Moreover, ferulic acid degradation was determined to some extent by P. liquidambari laccase. This study is the first report of an endophytic fungus that has a great potential for practical application in ferulic acid-contaminated environments. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Interaction of the retinoic acid signaling pathway with spicule formation in the marine sponge Suberites domuncula through activation of bone morphogenetic protein-1.

    Science.gov (United States)

    Müller, Werner E G; Binder, Michael; von Lintig, Johannes; Guo, Yue-Wei; Wang, Xiaohong; Kaandorp, Jaap A; Wiens, Matthias; Schröder, Heinz C

    2011-12-01

    The formation of the spicules in siliceous sponges involves the formation of cylinder-like structures in the extraspicular space, composed of the enzyme silicatein and the calcium-dependent lectin. Molecular cloning of the cDNAs (carotene dioxygenase, retinal dehydrogenase, and BMB-1 [bone morphogenic protein-1]) from the demosponge Suberites domuncula was performed. These tools were used to understand the retinoid metabolism in the animal by qRT-PCR, immunoblotting and TEM. We demonstrate that silintaphin-2, a silicatein-interacting protein, is processed from a longer-sized 15-kDa precursor to a truncated, shorter-sized 13kDa calcium-binding protein via proteolytic cleavage at the dipeptide Ala↓Asp, mediated by BMP-1. The expression of this protease as well as the expression of two key enzymes of the carotinoid metabolism, the β,β-carotene-15,15'-dioxygenase and the retinal dehydrogenase/reductase, were found to be strongly up-regulated by retinoic acid. Hence retinoic acid turned out to be a key factor in skeletogenesis in the most ancient still existing metazoans, the sponges. It is shown that retinoic acid regulates the formation of the organic cylinder that surrounds the axis of the spicules and enables, as a scaffold, the radial apposition of new silica layers and hence the growth of the spicules. 2011 Elsevier B.V. All rights reserved.

  11. Mechanisms of the Pellagragenic Effect of Leucine: Stimulation of Hepatic Tryptophan Oxidation by Administration of Branched-Chain Amino Acids to Healthy Human Volunteers and the Role of Plasma Free Tryptophan and Total Kynurenines

    OpenAIRE

    Abdulla A-B Badawy; Sarah L. Lake; Donald M. Dougherty

    2014-01-01

    The pellagragenic effect of leucine (Leu) has been proposed to involve modulation of L -tryptophan (Trp) metabolism along the hepatic kynurenine pathway. Here, we discuss some of the mechanisms suggested and report the effects in healthy volunteers of single doses of Leu (4.05–6.75 g) administered in a 16-amino acid mixture on concentrations of plasma Trp and its kynurenine metabolites. Flux of Trp through Trp 2,3-dioxygenase (TDO) is dose-dependently enhanced most probably by Leu and can be ...

  12. Influence of induction conditions on the expression of carbazole dioxygenase components (CarAa, CarAc, and CarAd) from Pseudomonas stutzeri in recombinant Escherichia coli using experimental design.

    Science.gov (United States)

    Larentis, Ariane Leites; Sampaio, Haryana de Cássia Cunha; Martins, Orlando Bonifácio; Rodrigues, Maria Isabel; Alves, Tito Lívio Moitinho

    2011-08-01

    Carbazole 1,9a-dioxygenase (CarA), the first enzyme in the carbazole degradation pathway used by Pseudomonas sp., was expressed in E. coli under different conditions defined by experimental design. This enzyme depends on the coexistence of three components containing [2Fe-2S] clusters: CarAa, CarAc, and CarAd. The catalytic site is present in CarAa. The genes corresponding to components of carbazole 1,9a-dioxygenase from P. stutzeri were cloned and expressed by salt induction in E. coli BL21-SI (a host that allows the enhancement of overexpressed proteins in the soluble fraction), using the vector pDEST™14. The expression of these proteins was performed under different induction conditions (cell concentration, temperature, and time), with the help of two-level factorial design. Cell concentration at induction (measured by absorbance at 600 nm) was tested at 0.5 and 0.8. After salt induction, expression was performed at 30 and 37°C, for 4 h and 24 h. Protein expression was evaluated by densitometry analysis. Expression of CarAa was enhanced by induction at a lower cell concentration and temperature and over a longer time, according to the analysis of the experimental design results. The results were validated at Abs (ind) = 0.3, 25°C, and 24 h, at which CarAa expression was three times higher than under the standard condition. The behavior of CarAc and CarAd was the inverse, with the best co-expression condition tested being the standard one (Abs (ind) = 0.5, T = 37°C, and t = 4 h). The functionality of the proteins expressed in E. coli was confirmed by the degradation of 20 ppm carbazole.

  13. Microbial degradation of 2,4-dichlorophenoxyacetic acid: Insight into the enzymes and catabolic genes involved, their regulation and biotechnological implications.

    Science.gov (United States)

    Kumar, Ajit; Trefault, Nicole; Olaniran, Ademola Olufolahan

    2016-01-01

    A considerable progress has been made to understand the mechanisms of biodegradation of 2,4-dichlorophenoxyacetic acid (2,4-D). 2,4-D biodegradation pathway has been elucidated in many microorganisms including Cupriavidus necator JMP134 (previously known as Wautersia eutropha, Ralstonia eutropha and Alcaligenes eutrophus) and Pseudomonas strains. It generally involves the side chain removal of 2,4-D by α-ketoglutarate-dependent 2,4-D dioxygenase (tfdA) to form 2,4-dichlorophenol (2,4-DCP); hydroxylation of 2,4-DCP by 2,4-DCP hydroxylase (tfdB) to form dichlorocatechol; ortho or meta cleavage of dichlorocatechol by chlorocatechol 1,2-dioxygenase (tfdC) to form 2,4-dichloro-cis,cis-muconate; conversion of 2,4-dichloro-cis,cis-muconate to 2-chlorodienelactone by chloromuconate cycloisomerase (tfdD); conversion of 2-chlorodienelactone to 2-chloromaleylacetate by chlorodienelactone hydrolase (tfdE) and, finally, conversion of 2-chloromaleylacetate to 3-oxoadepate via maleylacetate by chloromaleylacetate reductase and maleylacetate reductase (tfdF), respectively, which is funnelled to the tricarboxylic acid cycle. The latest review on microbial breakdown of 2,4-D, other halogenated aromatic pesticides, and related compounds was compiled by Haggblom, however, a considerable progress has been made in this area of research since then. Thus, this review focuses on the recent advancement on 2,4-D biodegradation, the enzymes, and genes involved and their biotechlogical implications.

  14. Folic Acid

    Science.gov (United States)

    Folic acid is a B vitamin. It helps the body make healthy new cells. Everyone needs folic acid. For women who may get pregnant, it is really important. Getting enough folic acid before and during pregnancy can prevent major birth ...

  15. Amino Acid Catabolism in Multiple Sclerosis Affects Immune Homeostasis.

    Science.gov (United States)

    Negrotto, Laura; Correale, Jorge

    2017-03-01

    Amino acid catabolism has been implicated in immunoregulatory mechanisms present in several diseases, including autoimmune disorders. Our aims were to assess expression and activity of enzymes involved in Trp and Arg catabolism, as well as to investigate amino acid catabolism effects on the immune system of multiple sclerosis (MS) patients. To this end, 40 MS patients, 30 healthy control subjects, and 30 patients with other inflammatory neurological diseases were studied. Expression and activity of enzymes involved in Trp and Arg catabolism (IDO1, IDO2, Trp 2,3-dioxygenase [TDO], arginase [ARG] 1, ARG2, inducible NO synthetase) were evaluated in PBMCs. Expression of general control nonrepressed 2 serine/threonine kinase and mammalian target of rapamycin (both molecules involved in sensing amino acid levels) was assessed in response to different stimuli modulating amino acid catabolism, as were cytokine secretion levels and regulatory T cell numbers. The results demonstrate that expression and activity of IDO1 and ARG1 were significantly reduced in MS patients compared with healthy control subjects and other inflammatory neurological diseases. PBMCs from MS patients stimulated with a TLR-9 agonist showed reduced expression of general control nonrepressed 2 serine/threonine kinase and increased expression of mammalian target of rapamycin, suggesting reduced amino acid catabolism in MS patients. Functionally, this reduction resulted in a decrease in regulatory T cells, with an increase in myelin basic protein-specific T cell proliferation and secretion of proinflammatory cytokines. In contrast, induction of IDO1 using CTLA-4 or a TLR-3 ligand dampened proinflammatory responses. Overall, these results highlight the importance of amino acid catabolism in the modulation of the immunological responses in MS patients. Molecules involved in these pathways warrant further exploration as potential new therapeutic targets in MS. Copyright © 2017 by The American Association of

  16. Lens epithelial cell apoptosis and intracellular Ca2+ increase in the presence of xanthurenic acid

    Directory of Open Access Journals (Sweden)

    Richter Christoph

    2002-04-01

    Full Text Available Abstract Background Xanthurenic acid is an endogenous product of tryptophan degradation by indoleamine 2,3-dioxygenase (IDO. We have previously reported that IDO is present in mammalian lenses, and xanthurenic acid is accumulated in the lenses with aging. Here, we studied the involvement of xanthurenic acid in the human lens epithelial cell physiology. Methods Human lens epithelial cells primary cultures were used. Control cells, and cells in the presence of xanthurenic acid grow in the dark. Western blot analysis and immunofluorescence studies were performed. Results In the presence of xanthurenic acid human lens epithelial cells undergo apoptosis-like cell death. In the control cells gelsolin stained the perinuclear region, whereas in the presence of 10 μM xanthurenic acid gelsolin is translocated to the cytoskeleton, but does not lead to cytoskeleton breakdown. In the same condition caspase-3 activation, and DNA fragmentation was observed. At low (5 to 10 μM of xanthurenic acid concentration, the elongation of the cytoskeleton was associated with migration of mitochondria and cytochrome c release. At higher concentrations xanthurenic acid (20 μM and 40 μM damaged mitochondria were observed in the perinuclear region, and nuclear DNA cleavage was observed. We observed an induction of calpain Lp 82 and an increase of free Ca2+ in the cells in a xanthurenic acid concentration-dependent manner. Conclusions The results show that xanthurenic acid accumulation in human lens epithelial cells disturbs the normal cell physiology and leads to a cascade of pathological events. Xanthurenic acid induces calpain Lp82 and caspases in the cells growing in the dark and can be involved in senile cataract development.

  17. Unravelling the gallic acid degradation pathway in bacteria: the gal cluster from Pseudomonas putida.

    Science.gov (United States)

    Nogales, Juan; Canales, Angeles; Jiménez-Barbero, Jesús; Serra, Beatriz; Pingarrón, José Manuel; García, José Luis; Díaz, Eduardo

    2011-01-01

    Gallic acid (3,4,5-trihydroxybenzoic acid, GA) is widely distributed in nature, being a major phenolic pollutant and a commonly used antioxidant and building-block for drug development. We have characterized the first complete cluster (gal genes) responsible for growth in GA in a derivative of the model bacterium Pseudomonas putida KT2440. GalT mediates specific GA uptake and chemotaxis, and highlights the critical role of GA transport in bacterial adaptation to GA consumption. The proposed GA degradation via the central intermediate 4-oxalomesaconic acid (OMA) was revisited and all enzymes involved have been identified. Thus, GalD is the prototype of a new subfamily of isomerases that catalyses a biochemical step that remained unknown, i.e. the tautomerization of the OMAketo generated by the GalA dioxygenase to OMAenol. GalB is the founding member of a new family of zinc-containing hydratases that converts OMAenol into 4-carboxy-4-hydroxy-2-oxoadipic acid (CHA). galC encodes the aldolase catalysing CHA cleavage to pyruvic and oxaloacetic acids. The presence of homologous gal clusters outside the Pseudomonas genus sheds light on the evolution and ecology of the gal genes in GA degraders. The gal genes were used for expanding the metabolic abilities of heterologous hosts towards GA degradation, and for engineering a GA cellular biosensor. © 2010 Blackwell Publishing Ltd.

  18. Large scale purification of puerarin from Puerariae Lobatae Radix through resins adsorption and acid hydrolysis.

    Science.gov (United States)

    Guo, Hai-Dong; Zhang, Qing-Feng; Chen, Ji-Guang; Shangguang, Xin-Cheng; Guo, Yu-Xian

    2015-02-01

    Puerarin is the major isoflavone of Puerariae Lobatae Radix. A method for large scale purification of puerarin was developed through resins adsorption and acid hydrolysis. The adsorption properties of six macroporous resins (D101, S-8, H103, X-5, HPD600, AB-8) were compared through the adsorption kinetics and equilibrium adsorption isotherms. Results showed that H103 resin had the best adsorption rate and capacity. The mass transfer zone motion model was further used for analyzing the fixed bed adsorption of H103 resin. Its length of mass transfer zone with 2mg/ml of puerarin in water and 10% ethanol at flow rate of 10ml/min were 41.6 and 47.5cm, while the equilibrium adsorption capacity was 165.03 and 102.88mg/g, respectively. By using 75% ethanol, puerarin could be well desorbed from the resin with recovery of 97.4%. Subsequently, H103 resin was successfully used for puerarin purification from Puerariae Lobatae Radix. The content of total isoflavones and puerarin in the resin adsorption product were 69.25% and 41.78%, respectively, which were about three times increased compared to the crude extract. Then, the product was hydrolyzed by 2.5M HCl at 90°C for 1h. Puerarin with purity of 90% and a byproduct daidzein with purity of 78% were obtained. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Probiotics Differently Affect Gut-Associated Lymphoid Tissue Indolamine-2,3-Dioxygenase mRNA and Cerebrospinal Fluid Neopterin Levels in Antiretroviral-Treated HIV-1 Infected Patients: A Pilot Study.

    Science.gov (United States)

    Scagnolari, Carolina; Corano Scheri, Giuseppe; Selvaggi, Carla; Schietroma, Ivan; Najafi Fard, Saeid; Mastrangelo, Andrea; Giustini, Noemi; Serafino, Sara; Pinacchio, Claudia; Pavone, Paolo; Fanello, Gianfranco; Ceccarelli, Giancarlo; Vullo, Vincenzo; d'Ettorre, Gabriella

    2016-09-27

    Recently the tryptophan pathway has been considered an important determinant of HIV-1 infected patients' quality of life, due to the toxic effects of its metabolites on the central nervous system (CNS). Since the dysbiosis described in HIV-1 patients might be responsible for the microbial translocation, the chronic immune activation, and the altered utilization of tryptophan observed in these individuals, we speculated a correlation between high levels of immune activation markers in the cerebrospinal fluid (CSF) of HIV-1 infected patients and the over-expression of indolamine-2,3-dioxygenase (IDO) at the gut mucosal surface. In order to evaluate this issue, we measured the levels of neopterin in CSF, and the expression of IDO mRNA in gut-associated lymphoid tissue (GALT), in HIV-1-infected patients on effective combined antiretroviral therapy (cART), at baseline and after six months of probiotic dietary management. We found a significant reduction of neopterin and IDO mRNA levels after the supplementation with probiotic. Since the results for the use of adjunctive therapies to reduce the levels of immune activation markers in CSF have been disappointing so far, our pilot study showing the efficacy of this specific probiotic product should be followed by a larger confirmatory trial.

  20. Structural Insights into Maize Viviparous14, a Key Enzyme in the Biosynthesis of the Phytohormone Abscisic Acid W

    Energy Technology Data Exchange (ETDEWEB)

    Messing, S.; Gabelli, S; Echeverria, I; Vogel, J; Guan, J; Tan, B; Klee, H; McCarty, D; Amzela, M

    2010-01-01

    The key regulatory step in the biosynthesis of abscisic acid (ABA), a hormone central to the regulation of several important processes in plants, is the oxidative cleavage of the 11,12 double bond of a 9-cis-epoxycarotenoid. The enzyme viviparous14 (VP14) performs this cleavage in maize (Zea mays), making it a target for the rational design of novel chemical agents and genetic modifications that improve plant behavior through the modulation of ABA levels. The structure of VP14, determined to 3.2-{angstrom} resolution, provides both insight into the determinants of regio- and stereospecificity of this enzyme and suggests a possible mechanism for oxidative cleavage. Furthermore, mutagenesis of the distantly related CCD1 of maize shows how the VP14 structure represents a template for all plant carotenoid cleavage dioxygenases (CCDs). In addition, the structure suggests how VP14 associates with the membrane as a way of gaining access to its membrane soluble substrate.

  1. Structural Insights into Maize Viviparous14, a Key Enzyme in the Biosynthesis of the Phytohormone Abscisic Acid

    Energy Technology Data Exchange (ETDEWEB)

    Messing, Simon A.J.; Gabelli, Sandra B.; Echeverria, Ignacia; Vogel, Jonathan T.; Guan, Jiahn Chou; Tan, Bao Cai; Klee, Harry J.; McCarty, Donald R.; Amzel, L. Mario (JHU); (Florida)

    2011-09-06

    The key regulatory step in the biosynthesis of abscisic acid (ABA), a hormone central to the regulation of several important processes in plants, is the oxidative cleavage of the 11,12 double bond of a 9-cis-epoxycarotenoid. The enzyme viviparous14 (VP14) performs this cleavage in maize (Zea mays), making it a target for the rational design of novel chemical agents and genetic modifications that improve plant behavior through the modulation of ABA levels. The structure of VP14, determined to 3.2-{angstrom} resolution, provides both insight into the determinants of regio- and stereospecificity of this enzyme and suggests a possible mechanism for oxidative cleavage. Furthermore, mutagenesis of the distantly related CCD1 of maize shows how the VP14 structure represents a template for all plant carotenoid cleavage dioxygenases (CCDs). In addition, the structure suggests how VP14 associates with the membrane as a way of gaining access to its membrane soluble substrate.

  2. Prediction of novel families of enzymes involved in oxidative and other complex modifications of bases in nucleic acids.

    Science.gov (United States)

    Iyer, Lakshminarayan M; Tahiliani, Mamta; Rao, Anjana; Aravind, L

    2009-06-01

    Modified bases in nucleic acids present a layer of information that directs biological function over and beyond the coding capacity of the conventional bases. While a large number of modified bases have been identified, many of the enzymes generating them still remain to be discovered. Recently, members of the 2-oxoglutarate- and iron(II)-dependent dioxygenase super-family, which modify diverse substrates from small molecules to biopolymers, were predicted and subsequently confirmed to catalyze oxidative modification of bases in nucleic acids. Of these, two distinct families, namely the AlkB and the kinetoplastid base J binding proteins (JBP) catalyze in situ hydroxylation of bases in nucleic acids. Using sensitive computational analysis of sequences, structures and contextual information from genomic structure and protein domain architectures, we report five distinct families of 2-oxoglutarate- and iron(II)-dependent dioxygenase that we predict to be involved in nucleic acid modifications. Among the DNA-modifying families, we show that the dioxygenase domains of the kinetoplastid base J-binding proteins belong to a larger family that includes the Tet proteins, prototyped by the human oncogene Tet1, and proteins from basidiomycete fungi, chlorophyte algae, heterolobosean amoeboflagellates and bacteriophages. We present evidence that some of these proteins are likely to be involved in oxidative modification of the 5-methyl group of cytosine leading to the formation of 5-hydroxymethylcytosine. The Tet/JBP homologs from basidiomycete fungi such as Laccaria and Coprinopsis show large lineage-specific expansions and a tight linkage with genes encoding a novel and distinct family of predicted transposases, and a member of the Maelstrom-like HMG family. We propose that these fungal members are part of a mobile transposon. To the best of our knowledge, this is the first report of a eukaryotic transposable element that encodes its own DNA-modification enzyme with a

  3. Ascorbic Acid

    Science.gov (United States)

    Ascorbic acid is used to prevent and treat scurvy, a disease caused by a lack of vitamin C in ... Ascorbic acid comes in extended-release (long-acting) capsules and tablets, lozenges, syrup, chewable tablets, and liquid drops to ...

  4. Obeticholic Acid

    Science.gov (United States)

    Obeticholic acid is used alone or in combination with ursodiol (Actigall, Urso) to treat primary biliary cholangitis (PBC; a ... were not treated successfully with ursodiol alone. Obeticholic acid is in a class of medications called farnesoid ...

  5. Aminocaproic Acid

    Science.gov (United States)

    Aminocaproic acid is used to control bleeding that occurs when blood clots are broken down too quickly. This type ... the baby is ready to be born). Aminocaproic acid is also used to control bleeding in the ...

  6. Ethacrynic Acid

    Science.gov (United States)

    Ethacrynic acid, a 'water pill,' is used to treat swelling and fluid retention caused by various medical problems. It ... Ethacrynic acid comes as a tablet to take by mouth. It is usually taken once or twice a day ...

  7. Mefenamic Acid

    Science.gov (United States)

    Mefenamic acid is used to relieve mild to moderate pain, including menstrual pain (pain that happens before or during a menstrual period). Mefenamic acid is in a class of medications called NSAIDs. ...

  8. Zoledronic acid overcomes chemoresistance and immunosuppression of malignant mesothelioma

    Science.gov (United States)

    Kopecka, Joanna; Gazzano, Elena; Sara, Orecchia; Ghigo, Dario; Riganti, Chiara

    2015-01-01

    The human malignant mesothelioma (HMM) is characterized by a chemoresistant and immunosuppressive phenotype. An effective strategy to restore chemosensitivity and immune reactivity against HMM is lacking. We investigated whether the use of zoledronic acid is an effective chemo-immunosensitizing strategy. We compared primary HMM samples with non-transformed mesothelial cells. HMM cells had higher rate of cholesterol and isoprenoid synthesis, constitutive activation of Ras/extracellular signal-regulated kinase1/2 (ERK1/2)/hypoxia inducible factor-1α (HIF-1α) pathway and up-regulation of the drug efflux transporter P-glycoprotein (Pgp). By decreasing the isoprenoid supply, zoledronic acid down-regulated the Ras/ERK1/2/HIF-1α/Pgp axis and chemosensitized the HMM cells to Pgp substrates. The HMM cells also produced higher amounts of kynurenine, decreased the proliferation of T-lymphocytes and expanded the number of T-regulatory (Treg) cells. Kynurenine synthesis was due to the transcription of the indoleamine 1,2 dioxygenase (IDO) enzyme, consequent to the activation of the signal transducer and activator of transcription-3 (STAT3). By reducing the activity of the Ras/ERK1/2/STAT3/IDO axis, zoledronic acid lowered the kyurenine synthesis and the expansion of Treg cells, and increased the proliferation of T-lymphocytes. Thanks to its ability to decrease Ras/ERK1/2 activity, which is responsible for both Pgp-mediated chemoresistance and IDO-mediated immunosuppression, zoledronic acid is an effective chemo-immunosensitizing agent in HMM cells. PMID:25544757

  9. Arabidopsis cysteine-rich receptor-like kinase 45 functions in the responses to abscisic acid and abiotic stresses

    KAUST Repository

    Zhang, Xiujuan

    2013-06-01

    The phytohormone abscisic acid (ABA) regulates seed germination, plant growth and development, and response to abiotic stresses such as drought and salt stresses. Receptor-like kinases are well known signaling components that mediate plant responses to developmental and environmental stimuli. Here, we characterized the biological function of an ABA and stress-inducible cysteine-rich receptor-like protein kinase, CRK45, in ABA signaling in Arabidopsis thaliana. The crk45 mutant was less sensitive to ABA than the wild type during seed germination and early seedling development, whereas CRK45 overexpression plants were more sensitive to ABA compared to the wild type. Furthermore, overexpression of CRK45 led to hypersensitivity to salt and glucose inhibition of seed germination, whereas the crk45 mutant showed the opposite phenotypes. In addition, CRK45 overexpression plants had enhanced tolerance to drought. Gene expression analyses revealed that the expression of representative stress-responsive genes was significantly enhanced in CRK45 overexpression plants in response to salt stress. ABA biosynthetic genes such as NCED3,. 22NCED3, 9-Cis-Epoxycarotenoid Dioxygenase 3.NCED5,. 33NCED5, 9-Cis-Epoxycarotenoid Dioxygenase 5.ABA2,. 44ABA2, Abscisic Acid Deficient 2. and AAO355AAO3, Abscisic Aldehyde Oxidase 3. were also constitutively elevated in the CRK45 overexpression plants. We concluded that CRK45 plays an important role in ABA signaling that regulates Arabidopsis seeds germination, early seedling development and abiotic stresses response, by positively regulating ABA responses in these processes. © 2013 Elsevier Masson SAS.

  10. Ibotenic acid and thioibotenic acid

    DEFF Research Database (Denmark)

    Hermit, Mette B; Greenwood, Jeremy R; Nielsen, Birgitte

    2004-01-01

    In this study, we have determined and compared the pharmacological profiles of ibotenic acid and its isothiazole analogue thioibotenic acid at native rat ionotropic glutamate (iGlu) receptors and at recombinant rat metabotropic glutamate (mGlu) receptors expressed in mammalian cell lines....... Thioibotenic acid has a distinct pharmacological profile at group III mGlu receptors compared with the closely structurally related ibotenic acid; the former is a potent (low microm) agonist, whereas the latter is inactive. By comparing the conformational energy profiles of ibotenic and thioibotenic acid...... with the conformations preferred by the ligands upon docking to mGlu1 and models of the other mGlu subtypes, we propose that unlike other subtypes, group III mGlu receptor binding sites require a ligand conformation at an energy level which is prohibitively expensive for ibotenic acid, but not for thioibotenic acid...

  11. Okadaic acid

    DEFF Research Database (Denmark)

    Danielsen, E Michael; Hansen, Gert H; Severinsen, Mai C K

    2014-01-01

    Okadaic acid (OA) is a polyether fatty acid produced by marine dinoflagellates and the causative agent of diarrhetic shellfish poisoning. The effect of OA on apical endocytosis in the small intestine was studied in organ cultured porcine mucosal explants. Within 0.5-1 h of culture, the toxin caused...... in acidic organelles, implying a different toxic mechanism of action. We propose that rapid induction of LBs, an indicator of phospholipidosis, should be included in the future toxicity profile of OA....

  12. The Crystal Structure of a Quercetin 2,3-Dioxygenase from Bacillus subtilis Suggests Modulation of Enzyme Activity by a Change in the Metal Ion at the Active Site(s)

    Energy Technology Data Exchange (ETDEWEB)

    Gopal, B.; Madan, Lalima L.; Betz, Stephen F.; Kossiakoff, Anthony A. (Indian); (UC); (GeneFormatics)

    2010-11-10

    Common structural motifs, such as the cupin domains, are found in enzymes performing different biochemical functions while retaining a similar active site configuration and structural scaffold. The soil bacterium Bacillus subtilis has 20 cupin genes (0.5% of the total genome) with up to 14% of its genes in the form of doublets, thus making it an attractive system for studying the effects of gene duplication. There are four bicupins in B. subtilis encoded by the genes yvrK, yoaN, yxaG, and ywfC. The gene products of yvrK and yoaN function as oxalate decarboxylases with a manganese ion at the active site(s), whereas YwfC is a bacitracin synthetase. Here we present the crystal structure of YxaG, a novel iron-containing quercetin 2,3-dioxygenase with one active site in each cupin domain. Yxag is a dimer, both in solution and in the crystal. The crystal structure shows that the coordination geometry of the Fe ion is different in the two active sites of YxaG. Replacement of the iron at the active site with other metal ions suggests modulation of enzymatic activity in accordance with the Irving-Williams observation on the stability of metal ion complexes. This observation, along with a comparison with the crystal structure of YvrK determined recently, has allowed for a detailed structure-function analysis of the active site, providing clues to the diversification of function in the bicupin family of proteins.

  13. Co-operative intermolecular kinetics of 2-oxoglutarate dependent dioxygenases may be essential for system-level regulation of plant cell physiology

    Directory of Open Access Journals (Sweden)

    Siddhartha eKundu

    2015-07-01

    Full Text Available Chlorosis, a common manifestation of Fe-deficiency in plants occurs in soils with an alkaline pH and/or a high concentration of calcium carbonate (calcareous, and is an important cause of depressed yield. The core premise of this work is the notion that the response to waning ferrous iron in the cytosol of graminaceous root cells is a well orchestrated pathophysiological event, wherein the principal co-ordinator is not restricted to a single protein, but is an assortment of enzymes. The 2OG-dependent sequences comprise members present in all major kingdoms of life, and catalyze the release of carbon dioxide and succinic acid from 2-oxoglutarate, and the hydroxylation of a substrate molecule. This generic reaction is, in most cases accompanied by a specialized conversion of the product. Here, I present a model of iron deficiency sensing and response actuation in the root cells of graminaceous crops. This hypothesis is centered on the rationale that, iron is an essential co-factor for the catalytic process, and therefore, declining cytosolic levels of this micronutrient could trigger compensatory measures. Regression models of empirically available kinetic data for iron and alpha-ketoglutarate were formulated, analysed, and compared. The results, when viewed in the context of the superfamily responding as a unit to this abiotic stressor, suggest that the 2OG-sequences can indeed, work together to mitigate the effects of this noxious stimulus.

  14. Individual monitoring of external exposure in terms of personal dose equivalent, Hp(d)

    International Nuclear Information System (INIS)

    Fantuzzi, E.

    2001-01-01

    The institute for Radiation Protection of ENEA - Bologna has organised a one day-workshop on the subject: Individual monitoring of external exposure in terms of personal dose equivalent, H p (d). The aim of the workshop was the discussion of the new implications and modifications to be expected in the routine individual monitoring of external radiation, due to the issue of the Decree 241/00 (G.U. 31/8/2000) in charge since 01/01/2001. The decree set up in Italian law the standards contained in the European Directive EURATOM 96/29-Basic Standards for the Protection of Health of Workers and the General Public against Dangers arising from Ionizing Radiation. Among others, the definition of the operational quantities for external radiation for personal and environmental monitoring, H p (d) e H * (d) respectively as defined by ICRU (International Commission for Radiation Units and Measurements), requires to update the methods of measurements and calibration of the personal dosemeters and environmental monitors. This report collects the papers presented at the workshop dealing with the Personal Dose Equivalent, H p (d), the conversion coefficients, H p (d)/K a e H p (d)/ , obtained through Monte Carlo calculations published by ICRU and ICRP (International Commission for Radiation Protection), the new calibration procedures and the practical implication in the routine of individual monitoring in terms of H p (d). Eventually, in the last chapter, the answers to Frequently Asked Questions (FAQ) are briefly reported [it

  15. Aristolochic Acids

    Science.gov (United States)

    ... often used as herbal medicines or in other botanical products in the United States and abroad. Aristolochic ... individuals with kidney or renal disease who consumed botanical products containing aristolochic acids. Animal Studies The findings ...

  16. Adaptation of phenylalanine and tyrosine catabolic pathway to hibernation in bats.

    Science.gov (United States)

    Pan, Yi-Hsuan; Zhang, Yijian; Cui, Jie; Liu, Yang; McAllan, Bronwyn M; Liao, Chen-Chung; Zhang, Shuyi

    2013-01-01

    Some mammals hibernate in response to harsh environments. Although hibernating mammals may metabolize proteins, the nitrogen metabolic pathways commonly activated during hibernation are not fully characterized. In contrast to the hypothesis of amino acid preservation, we found evidence of amino acid metabolism as three of five key enzymes, including phenylalanine hydroxylase (PAH), homogentisate 1,2-dioxygenase (HGD), fumarylacetoacetase (FAH), involved in phenylalanine and tyrosine catabolism were co-upregulated during hibernation in two distantly related species of bats, Myotis ricketti and Rhinolophus ferrumequinum. In addition, the levels of phenylalanine in the livers of these bats were significantly decreased during hibernation. Because phenylalanine and tyrosine are both glucogenic and ketogenic, these results indicate the role of this catabolic pathway in energy supply. Since any deficiency in the catabolism of these two amino acids can cause accumulations of toxic metabolites, these results also suggest the detoxification role of these enzymes during hibernation. A higher selective constraint on PAH, HPD, and HGD in hibernators than in non-hibernators was observed, and hibernators had more conserved amino acid residues in each of these enzymes than non-hibernators. These conserved amino acid residues are mostly located in positions critical for the structure and activity of the enzymes. Taken together, results of this work provide novel insights in nitrogen metabolism and removal of harmful metabolites during bat hibernation.

  17. Ex vivo immunosuppressive effects of mesenchymal stem cells on Crohn's disease mucosal T cells are largely dependent on indoleamine 2,3-dioxygenase activity and cell-cell contact.

    Science.gov (United States)

    Ciccocioppo, Rachele; Cangemi, Giuseppina C; Kruzliak, Peter; Gallia, Alessandra; Betti, Elena; Badulli, Carla; Martinetti, Miryam; Cervio, Marila; Pecci, Alessandro; Bozzi, Valeria; Dionigi, Paolo; Visai, Livia; Gurrado, Antonella; Alvisi, Costanza; Picone, Cristina; Monti, Manuela; Bernardo, Maria E; Gobbi, Paolo; Corazza, Gino R

    2015-07-24

    Crohn's disease (CD) is a disabling chronic enteropathy sustained by a harmful T-cell response toward antigens of the gut microbiota in genetically susceptible subjects. Growing evidence highlights the safety and possible efficacy of mesenchymal stem cells (MSCs) as a new therapeutic tool for this condition. Therefore, we aimed to investigate the effects of bone marrow-derived MSCs on pathogenic T cells with a view to clinical application. T-cell lines from both inflamed and non-inflamed colonic mucosal specimens of CD patients and from healthy mucosa of control subjects were grown with the antigen muramyl-dipeptide in the absence or presence of donors' MSCs. The MSC effects were evaluated in terms of T-cell viability, apoptotic rate, proliferative response, immunophenotype, and cytokine profile. The role of the indoleamine 2,3-dioxygenase (IDO) was established by adding a specific inhibitor, the 1-methyl-DL-tryptophan, and by using MSCs transfected with the small interfering RNA (siRNA) targeting IDO. The relevance of cell-cell contact was evaluated by applying transwell membranes. A significant reduction in both cell viability and proliferative response to muramyl-dipeptide, with simultaneous increase in the apoptotic rate, was found in T cells from both inflamed and non-inflamed CD mucosa when co-cultured with MSCs and was reverted by inhibiting IDO activity and expression. A reduction of the activated CD4(+)CD25(+) subset and increase of the CD3(+)CD69(+) population were also observed when T-cell lines from CD mucosa were co-cultured with MSCs. In parallel, an inhibitory effect was evident on the expression of the pro-inflammatory cytokines tumor necrosis factor-α, interferon-γ, interleukin-17A and -21, whereas that of the transforming growth factor-β and interleukin-6 were increased, and production of the tolerogenic molecule soluble HLA-G was high. These latter effects were almost completely eliminated by blocking the IDO, whose activity was upregulated in

  18. Fully automated radiosynthesis of N(1)-[(18)F]fluoroethyl-tryptophan and study of its biological activity as a new potential substrate for indoleamine 2,3-dioxygenase PET imaging.

    Science.gov (United States)

    Henrottin, Jean; Lemaire, Christian; Egrise, Dominique; Zervosen, Astrid; Van den Eynde, Benoit; Plenevaux, Alain; Franci, Xavier; Goldman, Serge; Luxen, André

    2016-06-01

    Indoleamine 2,3-dioxygenase (IDO) catalyzes the initial step in the catabolism of l-tryptophan along the kynurenine pathway and exerts immunosuppressive properties in inflammatory and tumor tissues by blocking locally T-lymphocyte proliferation. Recently, 1-(2-[(19)F]fluoroethyl)-dl-tryptophan (1-[(19)F]FE-dl-Trp) was reported as a good and specific substrate of this enzyme. Herein, the radiosynthesis of its radioactive isotopomer (1-[(18)F]FE-dl-Trp, dl-[(18)F]5) is presented along with in vitro enzymatic and cellular uptake studies. The one-pot n.c.a. radiosynthesis of this novel potential PET imaging tracer, including HPLC purification and formulation, has been fully automated on a FASTlab™ synthesizer. Chiral separation of both isomers and their formulation were implemented on a second cassette. In vitro enzymatic and cellular uptake studies were then conducted with the d-, l- and dl-radiotracers. The radiolabeling of the tosylate precursor was performed in DMF (in 5min; RCY: 57% (d.c.), n=3). After hydrolysis, HPLC purification and formulation, dl-[(18)F]5 was obtained with a global radiochemical yield of 18±3% (not decay corrected, n=7, in 80min) and a specific activity of 600±180GBq/μmol (n=5). The subsequent separation of l- and d-enantiomers was performed by chiral HPLC and both were obtained after formulation with an RCY (d.c.) of 6.1% and 5.8%, respectively. In vitro enzymatic assays reveal that l-[(18)F]5 is a better substrate than d-[(18)F]5 for human IDO. In vitro cellular assays show an IDO-specific uptake of the racemate varying from 30% to 50% of that of l-[(18)F]5, and a negligible uptake of d-[(18)F]5. In vitro studies show that l-[(18)F]5 is a good and specific substrate of hIDO, while presenting a very low efflux. These results confirm that l-[(18)F]5 could be a very useful PET radiotracer for IDO expressing cells in cancer imaging. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Zoledronic acid.

    Science.gov (United States)

    Coleman, Robert; Burkinshaw, Roger; Winter, Matthew; Neville-Webbe, Helen; Lester, Jim; Woodward, Emma; Brown, Janet

    2011-01-01

    Both bone metastases and fragility fractures due to bone loss result in considerable morbidity affecting quality of life and independence as well as placing complex demands on healthcare resources. Zoledronic acid is a widely used intravenous bisphosphonate that reduces this skeletal morbidity in both benign and malignant conditions. The incidence, clinical importance and prevention strategies to minimize side effects associated with the use of zoledronic acid are discussed with a particular focus on use in oncology where intensive monthly scheduling is required. This potentially increases the risk for adverse events over the 6-12 monthly administration used to treat benign bone diseases. A detailed understanding of the generally favorable safety profile of zoledronic acid, but particularly the potential for renal dysfunction and osteonecrosis of the jaw. When compared to many other therapies, especially in the cancer setting, the severity of adverse events related to zoledronic acid is generally mild and, with the exception of the acute phase response causing transient fever, myalgia and bone pain, side effects are infrequent. Thus, the benefits of treatment with zoledronic acid within its licensed indications almost always outweigh the risks.

  20. Acid Rain

    Science.gov (United States)

    Bricker, Owen P.; Rice, Karen C.; Dietrich, W.E.; Sposito, Garrison

    1997-01-01

    Acid deposition, or acid rain as it is more commonly referred to, has become a widely publicized environmental issue in the U.S. over the past decade. The term usually conjures up images of fish kills, dying forests, "dead" lakes, and damage to monuments and other historic artifacts. The primary cause of acid deposition is emission of S02 and NOx to the atmosphere during the combustion of fossil fuels. Oxidation of these compounds in the atmosphere forms strong acids - H2SO4 and HNO3 - which are returned to the Earth in rain, snow, fog, cloud water, and as dry deposition.Although acid deposition has only recently been recognized as an environmental problem in the U.S., it is not a new phenomenon (Cogbill & Likens 1974). As early as the middle of the 17th century in England, the deleterious effects of industrial emissions on plants, animals, and humans, and the atmospheric transport of pollutants between England and France had become issues of concern (Evelyn 1661, Graunt 1662). It is interesting that well over three hundred years ago in England, recommendations were made to move industry outside of towns and build higher chimneys to spread the pollution into "distant parts." Increasing the height of smokestacks has helped alleviate local problems, but has exacerbated others. In the U.S. the height of the tallest smokestack has more than doubled, and the average height of smokestacks has tripled since the 1950s (Patrick et al 1981). This trend occurred in most industrialized nations during the 20th century and has had the effect of transforming acid rain from a local urban problem into a problem of global scale.

  1. Lipoic Acid

    Directory of Open Access Journals (Sweden)

    Ramazan Tetikcok

    2015-09-01

    Full Text Available Lipoic acid, which is defined as a miralce antioxidan, is used by many departments. Eventhough clinical using data are very limited , it is used in treatment of diabetic neuropathy, physical therapy and rehabilitation clinic, dermatology clinic, geriatric clinics. It has usage area for cosmetic purposes. Although there are reports there are the direction of the effectiveness in these areas, the works done are not enough. Today lipoic acid , used in many areas ,is evaluated as universal antioxidant [J Contemp Med 2015; 5(3.000: 206-209

  2. Salicylhydroxamic acids

    Indian Academy of Sciences (India)

    to as topological indices, can be used for establishing QSAR of interest in pharmacology. A number of successful QSAR studies were made 4 based on Wms by means of which we can determine the ways in which the structural features of SHA and SHA derivatives influence the course of nucleic acid synthesis in a tumour ...

  3. Levulinic acid

    Directory of Open Access Journals (Sweden)

    Barbara Hachuła

    2013-09-01

    Full Text Available The title compound (systematic name: 4-oxopentanoic acid, C5H8O3, is close to planar (r.m.s. deviation = 0.0762 Å. In the crystal, the molecules interact via O—H...O hydrogen bonds in which the hydroxy O atoms act as donors and the ketone O atoms in adjacent molecules as acceptors, forming C(7 chains along [20-1].

  4. Pyridine 2,4-Dicarboxylic Acid Suppresses Tomato Seedling Growth.

    Science.gov (United States)

    Fragkostefanakis, Sotirios; Kaloudas, Dimitrios; Kalaitzis, Panagiotis

    2018-01-01

    Pyridine 2,4-dicarboxylic acid is a structural analog of 2-oxoglutarate and is known to inhibit 2-oxoglutare-dependent dioxygenases. The effect of this inhibitor in tomato seedlings grown in MS media supplied with various concentrations of PDCA was investigated, resulting in shorter roots and hypocotyls in a dose-dependent manner. The partial inhibition of growth in roots was more drastic compared to hypocotyls and was attributed to a decrease in the elongation of root and hypocotyl cells. Concentrations of 100 and 250 μM of PDCA decreased hydroxyproline content in roots while only the 250 μM treatment reduced the hydroxyproline content in shoots. Seedlings treated with 100 μM PDCA exhibited enhanced growth of hypocotyl and cotyledon cells and higher hydroxyproline content resulting in cotyledons with greater surface area. However, no alterations in hypocotyl length were observed. Prolyl 4 hydroxylases (P4Hs) are involved in the O-glycosylation of AGPs and were also highly expressed during seedling growth. Moreover PDCA induced a decrease in the accumulation of HRGPs and particularly in AGPs-bound epitopes in a dose dependent-manner while more drastic reduction were observed in roots compared to shoots. In addition, bulged root epidermal cells were observed at the high concentration of 250 μM which is characteristic of root tissues with glycosylation defects. These results indicate that PDCA induced pleiotropic effects during seedling growth while further studies are required to better investigate the physiological significance of this 2-oxoglutarate analog. This pharmacological approach might be used as a tool to better understand the physiological significance of HRGPs and probably P4Hs in various growth and developmental programs in plants.

  5. Pyridine 2,4-Dicarboxylic Acid Suppresses Tomato Seedling Growth

    Directory of Open Access Journals (Sweden)

    Sotirios Fragkostefanakis

    2018-01-01

    Full Text Available Pyridine 2,4-dicarboxylic acid is a structural analog of 2-oxoglutarate and is known to inhibit 2-oxoglutare-dependent dioxygenases. The effect of this inhibitor in tomato seedlings grown in MS media supplied with various concentrations of PDCA was investigated, resulting in shorter roots and hypocotyls in a dose-dependent manner. The partial inhibition of growth in roots was more drastic compared to hypocotyls and was attributed to a decrease in the elongation of root and hypocotyl cells. Concentrations of 100 and 250 μM of PDCA decreased hydroxyproline content in roots while only the 250 μM treatment reduced the hydroxyproline content in shoots. Seedlings treated with 100 μM PDCA exhibited enhanced growth of hypocotyl and cotyledon cells and higher hydroxyproline content resulting in cotyledons with greater surface area. However, no alterations in hypocotyl length were observed. Prolyl 4 hydroxylases (P4Hs are involved in the O-glycosylation of AGPs and were also highly expressed during seedling growth. Moreover PDCA induced a decrease in the accumulation of HRGPs and particularly in AGPs-bound epitopes in a dose dependent-manner while more drastic reduction were observed in roots compared to shoots. In addition, bulged root epidermal cells were observed at the high concentration of 250 μM which is characteristic of root tissues with glycosylation defects. These results indicate that PDCA induced pleiotropic effects during seedling growth while further studies are required to better investigate the physiological significance of this 2-oxoglutarate analog. This pharmacological approach might be used as a tool to better understand the physiological significance of HRGPs and probably P4Hs in various growth and developmental programs in plants.

  6. Metabolic regulation at the tricarboxylic acid and glyoxylate cycles of the lignin-degrading basidiomycete Phanerochaete chrysosporium against exogenous addition of vanillin.

    Science.gov (United States)

    Shimizu, Motoyuki; Yuda, Naoki; Nakamura, Tomofumi; Tanaka, Hiroo; Wariishi, Hiroyuki

    2005-10-01

    A proteomic differential display technique was utilized to study cellular responses of Phanerochaete chrysosporium exposed to vanillin, one of the key intermediates found during lignin biodegradation. Intracellular proteins were resolved by 2-DE and target protein spots were identified using MALDI-MS after in-gel tryptic digestions. Upon addition of vanillin to P. chrysosporium, up-regulation of homogentisate 1,2-dioxygenase, 1,4-benzoquinone reductases, aldehyde dehydrogenase, and aryl-alcohol dehydrogenase, which seem to play roles in vanillin metabolism, was observed. Furthermore, enzymes involved in glycolysis, the tricarboxylic acid cycle, the pentose-phosphate cycle, and heme biosynthesis were also activated. Up-regulation of extracellular peroxidase was also observed. One of the most unique phenomena against exogenous vanillin was a switch from the glyoxylate cycle to the tricarboxylic acid cycle, where a drastic increase in isocitrate dehydrogenase activity was observed. The exogenous addition of other aromatic compounds also caused an increase in its activity, which in turn triggered NAD(P)H production via the action of dehydrogenases in the tricarboxylic acid cycle, heme biosynthesis via the action of aminolevulinic acid synthase on succinyl-CoA, and energy production via activation of the mitochondrial electron transfer system. These metabolic shifts seem to be required for activating a metabolic system for aromatic compounds.

  7. Maleopimaric acid acetic acid solvate

    OpenAIRE

    Zhang, Meng; Zhou, Yong-hong; Guo, Xiao-xin; Hu, Li-hong

    2009-01-01

    The title compound, C24H32O5·C2H4O2, is a derivative of abietic acid. The two fused and unbridged cyclohexane rings have chair conformations and the anhydride ring is planar. Of the other three six-membered rings, two have boat conformations and one has a twist-boat conformation. The crystal structure is stabilized by intermolecular O—H...O and C—H...O hydrogen bonds.

  8. Rescue of IL-1β-induced reduction of human neurogenesis by omega-3 fatty acids and antidepressants.

    Science.gov (United States)

    Borsini, Alessandra; Alboni, Silvia; Horowitz, Mark A; Tojo, Luis M; Cannazza, Giuseppe; Su, Kuan-Pin; Pariante, Carmine M; Zunszain, Patricia A

    2017-10-01

    Both increased inflammation and reduced neurogenesis have been associated with the pathophysiology of major depression. We have previously described how interleukin-1 (IL-1) β, a pro-inflammatory cytokine increased in depressed patients, decreases neurogenesis in human hippocampal progenitor cells. Here, using the same human in vitro model, we show how omega-3 (ω-3) polyunsaturated fatty acids and conventional antidepressants reverse this reduction in neurogenesis, while differentially affecting the kynurenine pathway. We allowed neural cells to proliferate for 3days and further differentiate for 7days in the presence of IL-1β (10ng/ml) and either the selective serotonin reuptake inhibitor sertraline (1µM), the serotonin and norepinephrine reuptake inhibitor venlafaxine (1µM), or the ω-3 fatty acids eicosapentaenoic acid (EPA, 10µM) or docosahexaenoic acid (DHA, 10µM). Co-incubation with each of these compounds reversed the IL-1β-induced reduction in neurogenesis (DCX- and MAP2-positive neurons), indicative of a protective effect. Moreover, EPA and DHA also reversed the IL-1β-induced increase in kynurenine, as well as mRNA levels of indolamine-2,3-dioxygenase (IDO); while DHA and sertraline reverted the IL-1β-induced increase in quinolinic acid and mRNA levels of kynurenine 3-monooxygenase (KMO). Our results show common effects of monoaminergic antidepressants and ω-3 fatty acids on the reduction of neurogenesis caused by IL-1β, but acting through both common and different kynurenine pathway-related mechanisms. Further characterization of their individual properties will be of benefit towards improving a future personalized medicine approach. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

  9. Folic Acid and Pregnancy

    Science.gov (United States)

    ... Safe Videos for Educators Search English Español Folic Acid and Pregnancy KidsHealth / For Parents / Folic Acid and ... conception and during early pregnancy . What Is Folic Acid? Folic acid, sometimes called folate, is a B ...

  10. The Arabidopsis Vacuolar Sorting Receptor1 Is Required for Osmotic Stress-Induced Abscisic Acid Biosynthesis

    KAUST Repository

    Wang, Zhen-Yu

    2014-11-21

    Osmotic stress activates the biosynthesis of the phytohormone abscisic acid (ABA) through a pathway that is rate limited by the carotenoid cleavage enzyme 9-cis-epoxycarotenoid dioxygenase (NCED). To understand the signal transduction mechanism underlying the activation of ABA biosynthesis, we performed a forward genetic screen to isolate mutants defective in osmotic stress regulation of the NCED3 gene. Here, we identified the Arabidopsis (Arabidopsis thaliana) Vacuolar Sorting Receptor1 (VSR1) as a unique regulator of ABA biosynthesis. The vsr1 mutant not only shows increased sensitivity to osmotic stress, but also is defective in the feedback regulation of ABA biosynthesis by ABA. Further analysis revealed that vacuolar trafficking mediated by VSR1 is required for osmotic stress-responsive ABA biosynthesis and osmotic stress tolerance. Moreover, under osmotic stress conditions, the membrane potential, calcium flux, and vacuolar pH changes in the vsr1 mutant differ from those in the wild type. Given that manipulation of the intracellular pH is sufficient to modulate the expression of ABA biosynthesis genes, including NCED3, and ABA accumulation, we propose that intracellular pH changes caused by osmotic stress may play a signaling role in regulating ABA biosynthesis and that this regulation is dependent on functional VSR1.

  11. Direct and indirect inactivation of tumor cell protective catalase by salicylic acid and anthocyanidins reactivates intercellular ROS signaling and allows for synergistic effects.

    Science.gov (United States)

    Scheit, Katrin; Bauer, Georg

    2015-03-01

    Salicylic acid and anthocyanidins are known as plant-derived antioxidants, but also can provoke paradoxically seeming prooxidant effects in vitro. These prooxidant effects are connected to the potential of salicylic acid and anthocyanidins to induce apoptosis selectively in tumor cells in vitro and to inhibit tumor growth in animal models. Several epidemiological studies have shown that salicylic acid and its prodrug acetylsalicylic acid are tumor-preventive for humans. The mechanism of salicylic acid- and anthocyanidin-dependent antitumor effects has remained enigmatic so far. Extracellular apoptosis-inducing reactive oxygen species signaling through the NO/peroxynitrite and the HOCl signaling pathway specifically induces apoptosis in transformed cells. Tumor cells have acquired resistance against intercellular reactive oxygen species signaling through expression of membrane-associated catalase. Here, we show that salicylic acid and anthocyanidins inactivate tumor cell protective catalase and thus reactive apoptosis-inducing intercellular reactive oxygen species signaling of tumor cells and the mitochondrial pathway of apoptosis Salicylic acid inhibits catalase directly through its potential to transform compound I of catalase into the inactive compound II. In contrast, anthocyanidins provoke a complex mechanism for catalase inactivation that is initiated by anthocyanidin-mediated inhibition of NO dioxygenase. This allows the formation of extracellular singlet oxygen through the reaction between H(2)O(2) and peroxynitrite, amplification through a caspase8-dependent step and subsequent singlet oxygen-mediated inactivation of catalase. The combination of salicylic acid and anthocyanidins allows for a remarkable synergistic effect in apoptosis induction. This effect may be potentially useful to elaborate novel therapeutic approaches and crucial for the interpretation of epidemiological results related to the antitumor effects of secondary plant compounds. © The

  12. Dehydroabietic acid

    Directory of Open Access Journals (Sweden)

    Xiao-Ping Rao

    2009-10-01

    Full Text Available The title compound [systematic name: (1R,4aS,10aR-7-isopropyl-1,4a-dimethyl-1,2,3,4,4a,9,10,10a-octahydrophenanthrene-1-carboxylic acid], C20H28O2, has been isolated from disproportionated rosin which is obtained by isomerizing gum rosin with a Pd-C catalyst.. Two crystallographically independent molecules exist in the asymmetric unit. In each molecule, there are three six-membered rings, which adopt planar, half-chair and chair conformations. The two cyclohexane rings form a trans ring junction with the two methyl groups in axial positions. The crystal structure is stabilized by intermolecular O—H...O hydrogen bonds.

  13. Nicotinic Acid-Mediated Activation of Both Membrane and Nuclear Receptors towards Therapeutic Glucocorticoid Mimetics for Treating Multiple Sclerosis

    Directory of Open Access Journals (Sweden)

    W. Todd Penberthy

    2009-01-01

    Full Text Available Acute attacks of multiple sclerosis (MS are most commonly treated with glucocorticoids, which can provide life-saving albeit only temporary symptomatic relief. The mechanism of action (MOA is now known to involve induction of indoleamine 2,3-dioxygenase (IDO and interleukin-10 (IL-10, where IL-10 requires subsequent heme oxygenase-1 (HMOX-1 induction. Ectopic expression studies reveal that even small changes in expression of IDO, HMOX-1, or mitochondrial superoxide dismutase (SOD2 can prevent demyelination in experimental autoimmune encephalomyelitis (EAE animal models of MS. An alternative to glucocorticoids is needed for a long-term treatment of MS. A distinctly short list of endogenous activators of both membrane G-protein-coupled receptors and nuclear peroxisome proliferating antigen receptors (PPARs demonstrably ameliorate EAE pathogenesis by MOAs resembling that of glucocorticoids. These dual activators and potential MS therapeutics include endocannabinoids and the prostaglandin 15-deoxy-Δ12,14-PGJ2. Nicotinamide profoundly ameliorates and prevents autoimmune-mediated demyelination in EAE via maintaining levels of nicotinamide adenine dinucleotide (NAD, without activating PPAR nor any G-protein-coupled receptor. By comparison, nicotinic acid provides even greater levels of NAD than nicotinamide in many tissues, while additionally activating the PPAR-dependent pathway already shown to provide relief in animal models of MS after activation of GPR109a/HM74a. Thus nicotinic acid is uniquely suited for providing therapeutic relief in MS. However nicotinic acid is unexamined in MS research. Nicotinic acid penetrates the blood brain barrier, cures pellagric dementia, has been used for over 50 years clinically without toxicity, and raises HDL concentrations to a greater degree than any pharmaceutical, thus providing unparalleled benefits against lipodystrophy. Summary analysis reveals that the expected therapeutic benefits of high-dose nicotinic

  14. The c4h, tat, hppr and hppd genes prompted engineering of rosmarinic acid biosynthetic pathway in Salvia miltiorrhiza hairy root cultures.

    Directory of Open Access Journals (Sweden)

    Ying Xiao

    Full Text Available Rational engineering to produce biologically active plant compounds has been greatly impeded by our poor understanding of the regulatory and metabolic pathways underlying the biosynthesis of these compounds. Here we capitalized on our previously described gene-to-metabolite network in order to engineer rosmarinic acid (RA biosynthesis pathway for the production of beneficial RA and lithospermic acid B (LAB in Salvia miltiorrhiza hairy root cultures. Results showed their production was greatly elevated by (1 overexpression of single gene, including cinnamic acid 4-hydroxylase (c4h, tyrosine aminotransferase (tat, and 4-hydroxyphenylpyruvate reductase (hppr, (2 overexpression of both tat and hppr, and (3 suppression of 4-hydroxyphenylpyruvate dioxygenase (hppd. Co-expression of tat/hppr produced the most abundant RA (906 mg/liter and LAB (992 mg/liter, which were 4.3 and 3.2-fold more than in their wild-type (wt counterparts respectively. And the value of RA concentration was also higher than that reported before, that produced by means of nutrient medium optimization or elicitor treatment. It is the first report of boosting RA and LAB biosynthesis through genetic manipulation, providing an effective approach for their large-scale commercial production by using hairy root culture systems as bioreactors.

  15. Production of 10R-hydroxy unsaturated fatty acids from hempseed oil hydrolyzate by recombinant Escherichia coli cells expressing PpoC from Aspergillus nidulans.

    Science.gov (United States)

    Han, Jeong-Eun; Seo, Min-Ju; Shin, Kyung-Chul; Oh, Deok-Kun

    2016-09-01

    The first and second preferred substrates of recombinant Escherichia coli cells expressing 10R-dioxygenase (PpoC) from Aspergillus nidulans and the purified enzyme were linoleic acid and α-linolenic acid, respectively. PpoC in cells showed higher thermal and reaction stabilities compared to purified PpoC. Thus, 10R-hydroxy unsaturated fatty acids were produced from linoleic acid, α-linolenic acid, and hempseed oil hydrolyzate containing linoleic acid and α-linolenic acid as substrates by whole recombinant cells expressing PpoC. The optimal reaction conditions for the production of 10R-hydroxy-8E,12Z-octadecadienoic acid (10R-HODE) were pH 8.0, 30 °C, 250 rpm, 5 % (v/v) dimethyl sulfoxide, 5 g l(-1) linoleic acid, and 60 g l(-1) cells in 100-ml baffled flask. Under these conditions, whole recombinant cells expressing PpoC produced 2.7 g l(-1) 10R-HODE from 5 g l(-1) linoleic acid for 40 min, with a conversion yield of 54 % (w/w) and a productivity of 4.0 g l(-1) h(-1); produced 2.2 g l(-1) 10R-hydroxy-8E,12Z,15Z-octadecatrienoic acid (10R-HOTrE) from 3 g l(-1) α-linolenic acid for 30 min, with a conversion yield of 72 % (w/w) and a productivity of 4.3 g l(-1) h(-1); and produced 1.8 g l(-1) 10R-HODE and 0.5 g l(-1) 10R-HOTrE from 5 g l(-1) hempseed oil hydrolyzate containing 2.5 g l(-1) linoleic acid and 1.0 g l(-1) α-linolenic acid for 30 min, with a conversion yield of 74 and 51 % (w/w), respectively, and a productivity of 3.6 and 1.0 g l(-1) h(-1), respectively. To the best of our knowledge, this is the first report on the biotechnological production of 10R-hydroxy unsaturated fatty acids.

  16. [Teichoic acids from lactic acid bacteria].

    Science.gov (United States)

    Livins'ka, O P; Harmasheva, I L; Kovalenko, N K

    2012-01-01

    The current view of the structural diversity of teichoic acids and their involvement in the biological activity of lactobacilli has been reviewed. The mechanisms of effects of probiotic lactic acid bacteria, in particular adhesive and immunostimulating functions have been described. The prospects of the use of structure data of teichoic acid in the assessment of intraspecific diversity of lactic acid bacteria have been also reflected.

  17. Uric acid test (image)

    Science.gov (United States)

    Uric acid urine test is performed to check for the amount of uric acid in urine. Urine is collected over a 24 ... for testing. The most common reason for measuring uric acid levels is in the diagnosis or treatment of ...

  18. Uric acid - urine

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003616.htm Uric acid urine test To use the sharing features on this page, please enable JavaScript. The uric acid urine test measures the level of uric acid ...

  19. Plasma amino acids

    Science.gov (United States)

    Amino acids blood test ... types of methods used to determine the individual amino acid levels in the blood. ... test is done to measure the level of amino acids in the blood. An increased level of a ...

  20. Facts about Folic Acid

    Science.gov (United States)

    ... Information For… Media Policy Makers Facts About Folic Acid Language: English (US) Español (Spanish) Recommend on Facebook ... of the baby’s brain and spine. About folic acid Folic acid is a B vitamin. Our bodies ...

  1. Methylmalonic acid blood test

    Science.gov (United States)

    ... medlineplus.gov/ency/article/003565.htm Methylmalonic acid blood test To use the sharing features on this page, please enable JavaScript. The methylmalonic acid blood test measures the amount of methylmalonic acid in the ...

  2. Characterization of major ripening events during softening in grape: turgor, sugar accumulation, abscisic acid metabolism, colour development, and their relationship with growth

    Science.gov (United States)

    Castellarin, Simone D.; Gambetta, Gregory A.; Wada, Hiroshi; Krasnow, Mark N.; Cramer, Grant R.; Peterlunger, Enrico; Shackel, Kenneth A.; Matthews, Mark A.

    2016-01-01

    Along with sugar accumulation and colour development, softening is an important physiological change during the onset of ripening in fruits. In this work, we investigated the relationships among major events during softening in grape (Vitis vinifera L.) by quantifying elasticity in individual berries. In addition, we delayed softening and inhibited sugar accumulation using a mechanical growth-preventing treatment in order to identify processes that are sugar and/or growth dependent. Ripening processes commenced on various days after anthesis, but always at similarly low elasticity and turgor. Much of the softening occurred in the absence of other changes in berry physiology investigated here. Several genes encoding key cell wall-modifying enzymes were not up-regulated until softening was largely completed, suggesting softening may result primarily from decreases in turgor. Similarly, there was no decrease in solute potential, increase in sugar concentration, or colour development until elasticity and turgor were near minimum values, and these processes were inhibited when berry growth was prevented. Increases in abscisic acid occurred early during softening and in the absence of significant expression of the V. vinifera 9-cis-epoxycarotenoid dioxygenases. However, these increases were coincident with decreases in the abscisic acid catabolite diphasic acid, indicating that initial increases in abscisic acid may result from decreases in catabolism and/or exogenous import. These data suggest that softening, decreases in turgor, and increases in abscisic acid represent some of the earliest events during the onset of ripening. Later, physical growth, further increases in abscisic acid, and the accumulation of sugar are integral for colour development. PMID:26590311

  3. Acid distribution in phosphoric acid fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Okae, I.; Seya, A.; Umemoto, M. [Fuji Electric Co., Ltd., Chiba (Japan)

    1996-12-31

    Electrolyte acid distribution among each component of a cell is determined by capillary force when the cell is not in operation, but the distribution under the current load conditions had not been clear so far. Since the loss of electrolyte acid during operation is inevitable, it is necessary to store enough amount of acid in every cell. But it must be under the level of which the acid disturbs the diffusion of reactive gases. Accordingly to know the actual acid distribution during operation in a cell is very important. In this report, we carried out experiments to clarify the distribution using small single cells.

  4. Enhanced mineralization of [U-(14)C]2,4-dichlorophenoxyacetic acid in soil from the rhizosphere of Trifolium pratense.

    Science.gov (United States)

    Shaw, Liz J; Burns, Richard G

    2004-08-01

    Enhanced biodegradation in the rhizosphere has been reported for many organic xenobiotic compounds, although the mechanisms are not fully understood. The purpose of this study was to discover whether rhizosphere-enhanced biodegradation is due to selective enrichment of degraders through growth on compounds produced by rhizodeposition. We monitored the mineralization of [U-(14)C]2,4-dichlorophenoxyacetic acid (2,4-D) in rhizosphere soil with no history of herbicide application collected over a period of 0 to 116 days after sowing of Lolium perenne and Trifolium pratense. The relationships between the mineralization kinetics, the number of 2,4-D degraders, and the diversity of genes encoding 2,4-D/alpha-ketoglutarate dioxygenase (tfdA) were investigated. The rhizosphere effect on [(14)C]2,4-D mineralization (50 microg g(-1)) was shown to be plant species and plant age specific. In comparison with nonplanted soil, there were significant (P mineralization rate for 25- and 60-day T. pratense soil but not for 116-day T. pratense rhizosphere soil or for L. perenne rhizosphere soil of any age. Numbers of 2,4-D degraders in planted and nonplanted soil were low (most probable number, mineralization in T. pratense rhizosphere soil is not due to enrichment of 2,4-D-degrading microorganisms by rhizodeposits. We suggest an alternative mechanism in which one or more components of the rhizodeposits induce the 2,4-D pathway.

  5. The plant cuticle is required for osmotic stress regulation of abscisic acid biosynthesis and osmotic stress tolerance in Arabidopsis

    KAUST Repository

    Wang, Zhenyu

    2011-05-01

    Osmotic stress activates the biosynthesis of abscisic acid (ABA). One major step in ABA biosynthesis is the carotenoid cleavage catalyzed by a 9-cis epoxycarotenoid dioxygenase (NCED). To understand the mechanism for osmotic stress activation of ABA biosynthesis, we screened for Arabidopsis thaliana mutants that failed to induce the NCED3 genee xpression in response to osmotic stress treatments. The ced1 (for 9-cis epoxycarotenoid dioxy genase defective 1) mutant isolated in this study showed markedly reduced expression of NCED3 in response to osmotic stress (polyethylene glycol)treatments compared with the wild type. Other ABA biosynthesis genes are also greatly reduced in ced1 under osmotic stress. ced1 mutant plants are very sensitive to even mild osmotic stress. Map-based cloning revealed unexpectedly thatCED1 encodes a putative a/b hydrolase domain-containing protein and is allelic to the BODYGUARD gene that was recently shown to be essential for cuticle biogenesis. Further studies discovered that other cut in biosynthesis mutants are also impaired in osmotic stress induction of ABA biosynthesis genes and are sensitive to osmotic stress. Our work demonstrates that the cuticle functions not merely as a physical barrier to minimize water loss but also mediates osmotic stress signaling and tolerance by regulating ABA biosynthesis and signaling. © 2011 American Society of Plant Biologists. All rights reserved.

  6. Toxicity of adipic acid.

    Science.gov (United States)

    Kennedy, Gerald L

    2002-05-01

    Adipic acid has very low acute toxicity in rats with an LD50 > 5000 mg/kg. Adipic acid produced mild to no skin irritation on intact guinea pig skin as a 50% concentration in propylene glycol; it was not a skin sensitizer. Adipic acid caused mild conjunctival irritation in washed rabbit eyes; in unwashed rabbit eyes, there was mild conjunctival irritation, minimal iritis, but no corneal effects. Adipic acid dust may irritate the mucous membranes of the lungs and nose. In a 2-year feeding study, rats fed adipic acid at concentrations up to 5% in the diet exhibited only weight loss. Adipic acid is not genetically active in a wide variety of assay systems. Adipic acid caused no developmental toxicity in mice, rats, rabbits, or hamsters when administered orally. Adipic acid is partially metabolized in humans; the balance is eliminated unchanged in the urine. Adipic acid is slightly to moderately toxic to fish, daphnia, and algae in acute tests.

  7. Acid Thunder: Acid Rain and Ancient Mesoamerica

    Science.gov (United States)

    Kahl, Jonathan D. W.; Berg, Craig A.

    2006-01-01

    Much of Mesoamerica's rich cultural heritage is slowly eroding because of acid rain. Just as water dissolves an Alka-Seltzer tablet, acid rain erodes the limestone surfaces of Mexican archaeological sites at a rate of about one-half millimeter per century (Bravo et al. 2003). A half-millimeter may not seem like much, but at this pace, a few…

  8. Auto-triggerable HPD sensors fully readout on ethernet: Applications for high-energy physics and medical imaging

    CERN Document Server

    Katsanevas, S; Marteau, J; Moret, G

    2003-01-01

    The OPERA project is dedicated to neutrino oscillation search in the CNGS neutrino beam from CERN to Gran Sasso (Experimental Proposal, CERN/SPSC 2000-028, SPSC/P318, LNGS P25/2000, July 10, 2000). The experiment is designed to characterize the interactions of nu//tau resulting of the nu//mu yields nu//tau oscillation. The main element of the detector is a brick 10.2 cm multiplied by 12.8 cm cross- section consisting of 56 emulsion sheets 100 mum wide, interleaved with 1 mm lead plates. These bricks are assembled in walls of similar to 7 m side. A total of 72 walls is foreseen for the OPERA experiment with a total fiducial mass of 2 ktons. When a neutrino interaction occurs, the tracks of the charged particles are recorded in the emulsions with a high accuracy and the topology of the event is fully reconstructed with an automatic scanning of the emulsions. The role of the target tracker in OPERA is to locate the brick where the primary neutrino interaction occurs, to provide triggers and to make a coarser rec...

  9. Results of the regional intercomparison exercise for the determination of operational quantity Hp(d) in Latin America

    International Nuclear Information System (INIS)

    Saravi, M.; Zaretzky, A.; Lindner, C.; Diaz, J.; Walwyn, G.; Souza, D.; Amorin, R.; Gregory, B.; Papadopulos, S.; Meghzifene, A.; Ferruz Cruz, P.; Cruz Suarez, R.

    2005-01-01

    Full text: Several intercomparison exercises were organized by the International Atomic Energy Agency (IAEA) on the determination of operational quantities at the regional or interregional basis. These exercises revealed significant differences in the approach, methods and assumptions, and consequently in the measurement results obtained by participating laboratories. In the Latin America region, an intercomparison for determination of operational quantity Hp(10), organized within the frame of a technical cooperation regional project, was completed mid-2004, as a follow-up to previous exercises carried out during the 1990s. Eighteen laboratories from 19 member states participated in the first phase; the second phase grouped 15 laboratories from 16 member states. Dosimeter irradiations (5 different radiation qualities for photon simulating workplace fields) were done by 4 Secondary Standards Dosimetry Laboratories (SSDL). The preparations for the exercise involved an audit by the IAEA SSDL, where reference irradiations were provided to all participants for verification of their system. During the first phase (2002/03), only 9 out of 18 laboratories met the performance requirements for such monitoring services. Necessary corrective actions and procedure verification were implemented, and staff involved in these evaluations were subsequently trained. During the second phase (2004), 11 out of 15 laboratories fulfilled the performance criteria. The 4 laboratories still having difficulties in assessing occupational exposure participated in a results meeting, during which problem areas were identified. An ongoing technical cooperation mission is expected to assist these laboratories accordingly. There has been a definite improvement in the second phase and most laboratories demonstrated a good performance in the quantity tested. The technical results clearly show that the laboratories' capability in assessing occupational exposure from external sources of radiation is adequate. These results underline the importance of such an intercomparison programme as a key element towards the harmonization of quantities and units on an international level. This paper presents the intercomparison results. It must be noted that member states strongly recommend that the IAEA continue acting as a focal point for, inter alia, training in all forms, particularly in measurements and dosimetry techniques. This exercise also stressed the importance for the IAEA to take an active role in establishing a network of monitoring laboratories for radiation protection purposes, as it would provide for better information exchange for similar projects. (author)

  10. Future needs for improvement of NIHL awareness training and HPD practices in the South African mining industry

    CSIR Research Space (South Africa)

    Edwards, A

    2012-08-01

    Full Text Available Introduction 5 Definitions Awareness training Education, motivation and training Education ? to ensure the worker has the knowledge about the risks of the noise hazard and the effects on the hearing health and safety of workers Motivation... methods and self motivated prevention and protection of hearing 4. Amount of training in relation to extent of the problem 5. Properly equipped trainers- Who should do the training 10 Awareness training - Data analysis What should it look...

  11. Acid Deposition Phenomena

    International Nuclear Information System (INIS)

    Ramadan, A.E.K.

    2004-01-01

    Acid deposition, commonly known as acid rain, occurs when emissions from the combustion of fossil fuels and other industrial processes undergo complex chemical reactions in the atmosphere and fall to the earth as wet deposition (rain, snow, cloud, fog) or dry deposition (dry particles, gas). Rain and snow are already naturally acidic, but are only considered problematic when less than a ph of 5.0 The main chemical precursors leading to acidic conditions are atmospheric concentrations of sulfur dioxide (SO 2 ) and nitrogen oxides (NO x ). When these two compounds react with water, oxygen, and sunlight in the atmosphere, the result is sulfuric (H 2 SO 4 ) and nitric acids (HNO 3 ), the primary agents of acid deposition which mainly produced from the combustion of fossil fuel and from petroleum refinery. Airborne chemicals can travel long distances from their sources and can therefore affect ecosystems over broad regional scales and in locations far from the sources of emissions. According to the concern of petroleum ministry with the environment and occupational health, in this paper we will discussed the acid deposition phenomena through the following: Types of acidic deposition and its components in the atmosphere Natural and man-made sources of compounds causing the acidic deposition. Chemical reactions causing the acidic deposition phenomenon in the atmosphere. Factors affecting level of acidic deposition in the atmosphere. Impact of acid deposition. Procedures for acidic deposition control in petroleum industry

  12. Amino Acid Metabolism Disorders

    Science.gov (United States)

    ... acids are "building blocks" that join together to form proteins. If you have one of these disorders, your body may have trouble breaking down certain amino acids. Or there may be a problem getting the ...

  13. Uric acid - blood

    Science.gov (United States)

    ... acid in blood Images Blood test Uric acid crystals References Edwards NL. Crystal deposition diseases. In: Goldman L, Schafer AI, eds. ... M. is among the first to achieve this important distinction for online health information and services. Learn ...

  14. Omega-6 Fatty Acids

    Science.gov (United States)

    Omega-6 fatty acids are types of fats. Some types are found in vegetable oils, including corn, evening primrose seed, safflower, and soybean oils. Other types of omega-6 fatty acids are found in black currant seed, borage seed, ...

  15. Pantothenic acid and biotin

    Science.gov (United States)

    ... gov/ency/article/002410.htm Pantothenic acid and biotin To use the sharing features on this page, please enable JavaScript. Pantothenic acid and biotin are types of B vitamins. They are water- ...

  16. Acid-fast stain

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003766.htm Acid-fast stain To use the sharing features on this page, please enable JavaScript. The acid-fast stain is a laboratory test that determines ...

  17. Hydrochloric acid poisoning

    Science.gov (United States)

    Hydrochloric acid is a clear, poisonous liquid. It is highly corrosive, which means it immediately causes severe damage, such ... poisoning due to swallowing or breathing in hydrochloric acid. This article is for information only. Do NOT ...

  18. Aminolevulinic Acid Topical

    Science.gov (United States)

    Aminolevulinic acid is used in combination with photodynamic therapy (PDT; special blue light) to treat actinic keratoses (small crusty ... skin cancer) of the face or scalp. Aminolevulinic acid is in a class of medications called photosensitizing ...

  19. Zoledronic Acid Injection

    Science.gov (United States)

    Zoledronic acid (Reclast) is used to prevent or treat osteoporosis (condition in which the bones become thin and weak ... of life,' end of regular menstrual periods). Zoledronic acid (Reclast) is also used to treat osteoporosis in ...

  20. Azelaic Acid Topical

    Science.gov (United States)

    Azelaic acid gel and foam is used to clear the bumps, lesions, and swelling caused by rosacea (a skin ... redness, flushing, and pimples on the face). Azelaic acid cream is used to treat the pimples and ...

  1. Aminocaproic Acid Injection

    Science.gov (United States)

    Aminocaproic acid injection is used to control bleeding that occurs when blood clots are broken down too quickly. This ... the baby is ready to be born). Aminocaproic acid injection is also used to control bleeding in ...

  2. Deoxycholic Acid Injection

    Science.gov (United States)

    Deoxycholic acid injection is used to improve the appearance and profile of moderate to severe submental fat ('double chin'; fatty tissue located under the chin). Deoxycholic acid injection is in a class of medications called ...

  3. Valproic Acid and Pregnancy

    Science.gov (United States)

    ... live chat Live Help Fact Sheets Share Valproic Acid Monday, 01 January 2018 In every pregnancy, a ... This sheet talks about whether exposure to valproic acid may increase the risk for birth defects over ...

  4. Lactic acid test

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003507.htm Lactic acid test To use the sharing features on this page, please enable JavaScript. Lactic acid is mainly produced in muscle cells and red ...

  5. Sulfuric acid poisoning

    Science.gov (United States)

    Sulfuric acid is a very strong chemical that is corrosive. Corrosive means it can cause severe burns and ... or mucous membranes. This article discusses poisoning from sulfuric acid. This article is for information only. Do NOT ...

  6. Reinvestigation of a Ru(2)-incorporated polyoxometalate dioxygenase precatalyst, "[WZnRu(2)(III)(H(2)O)(OH)(ZnW(9)O(34))(2)](11-)": evidence for marginal,

    Science.gov (United States)

    Morris, Aimee M; Anderson, Oren P; Finke, Richard G

    2009-05-18

    A 1997 Nature paper (Nature 1997, 388, 353-355) and subsequent 1998 J. Am. Chem. Soc. paper (J. Am. Chem. Soc. 1998, 120, 11969-11976) reported that a putative Ru(2)-substituted polyoxoanion, "[WZnRu(2)(III)(H(2)O)(OH)(ZnW(9)O(34))(2)](11-)", (1), is an all inorganic dioxygenase able to incorporate one O(2) into two adamantane CH bonds to yield 2 equiv of 1-adamantanol as the primary product. In a subsequent 2005 Inorg. Chem. publication (Inorg. Chem. 2005, 44, 4175-4188), strong evidence was provided that the putative dioxygenase chemistry is, instead, the result of classic autoxidation catalysis. That research raised the question of whether the reported Ru(2) precatalyst, 1, was pure or even if it contained two Ru atoms, since Ru is known to be difficult to substitute into polyoxoanion structures (Nomiya, K.; Torii, H.; Nomura, K.; Sato, Y. J. Chem. Soc. Dalton Trans. 2001, 1506-1521). After our research group had contact with three other groups who also had difficulties reproducing the reported synthesis and composition of 1, we decided to re-examine 1 in some detail. Herein we provide evidence that the claimed 1 actually appears to be the parent polyoxoanion [WZn(3)(H(2)O)(2)(ZnW(9)O(34))(2)](12-) with small amounts of Ru (

  7. Immunomodulatory Effects of the Mycosporine-Like Amino Acids Shinorine and Porphyra-334

    Directory of Open Access Journals (Sweden)

    Kathrin Becker

    2016-06-01

    Full Text Available Mycosporine-like amino acids (MAAs are secondary metabolites, produced by a large variety of microorganisms including algae, cyanobacteria, lichen and fungi. MAAs act as UV-absorbers and photo-protectants. MAAs are suggested to exert pharmaceutical relevant bioactivities in the human system. We particularly focused on their effect on defence and regulatory pathways that are active in inflamed environments. The MAAs shinorine and porphyra-334 were isolated and purified from the red algae Porphyra sp. using chromatographic methods. The effect of MAAs on central signaling cascades, such as transcription factor nuclear factor kappa b (NF-κB activation, as well as tryptophan metabolism, was investigated in human myelomonocytic THP-1 and THP-1-Blue cells. Cells were exposed to the MAAs in the presence or absence of lipopolysaccharide (LPS. NF-κB activity and the activity of tryptophan degrading enzyme indoleamine 2,3-dioxygenase (IDO-1 were used as readout. Compounds were tested in the concentration range from 12.5 to 200 µg/mL. Both MAAs were able to induce NF-κB activity in unstimulated THP-1-Blue cells, whereby the increase was dose-dependent and more pronounced with shinorine treatment. While shinorine also slightly superinduced NF-κB in LPS-stimulated cells, porphyra-334 reduced NF-κB activity in this inflammatory background. Modulation of tryptophan metabolism was moderate, suppressive in stimulated cells with the lower treatment concentration of both MAAs and with the unstimulated cells upon porphyra-334 treatment. Inflammatory pathways are affected by MAAs, but despite the structural similarity, diverse effects were observed.

  8. Immunomodulatory Effects of the Mycosporine-Like Amino Acids Shinorine and Porphyra-334.

    Science.gov (United States)

    Becker, Kathrin; Hartmann, Anja; Ganzera, Markus; Fuchs, Dietmar; Gostner, Johanna M

    2016-06-21

    Mycosporine-like amino acids (MAAs) are secondary metabolites, produced by a large variety of microorganisms including algae, cyanobacteria, lichen and fungi. MAAs act as UV-absorbers and photo-protectants. MAAs are suggested to exert pharmaceutical relevant bioactivities in the human system. We particularly focused on their effect on defence and regulatory pathways that are active in inflamed environments. The MAAs shinorine and porphyra-334 were isolated and purified from the red algae Porphyra sp. using chromatographic methods. The effect of MAAs on central signaling cascades, such as transcription factor nuclear factor kappa b (NF-κB) activation, as well as tryptophan metabolism, was investigated in human myelomonocytic THP-1 and THP-1-Blue cells. Cells were exposed to the MAAs in the presence or absence of lipopolysaccharide (LPS). NF-κB activity and the activity of tryptophan degrading enzyme indoleamine 2,3-dioxygenase (IDO-1) were used as readout. Compounds were tested in the concentration range from 12.5 to 200 µg/mL. Both MAAs were able to induce NF-κB activity in unstimulated THP-1-Blue cells, whereby the increase was dose-dependent and more pronounced with shinorine treatment. While shinorine also slightly superinduced NF-κB in LPS-stimulated cells, porphyra-334 reduced NF-κB activity in this inflammatory background. Modulation of tryptophan metabolism was moderate, suppressive in stimulated cells with the lower treatment concentration of both MAAs and with the unstimulated cells upon porphyra-334 treatment. Inflammatory pathways are affected by MAAs, but despite the structural similarity, diverse effects were observed.

  9. Acid Rain Study Guide.

    Science.gov (United States)

    Hunger, Carolyn; And Others

    Acid rain is a complex, worldwide environmental problem. This study guide is intended to aid teachers of grades 4-12 to help their students understand what acid rain is, why it is a problem, and what possible solutions exist. The document contains specific sections on: (1) the various terms used in conjunction with acid rain (such as acid…

  10. The Acid Rain Reader.

    Science.gov (United States)

    Stubbs, Harriett S.; And Others

    A topic which is often not sufficiently dealt with in elementary school textbooks is acid rain. This student text is designed to supplement classroom materials on the topic. Discussed are: (1) "Rain"; (2) "Water Cycle"; (3) "Fossil Fuels"; (4) "Air Pollution"; (5) "Superstacks"; (6) "Acid/Neutral/Bases"; (7) "pH Scale"; (8) "Acid Rain"; (9)…

  11. Amino acids and proteins

    NARCIS (Netherlands)

    van Goudoever, Johannes B.; Vlaardingerbroek, Hester; van den Akker, Chris H.; de Groof, Femke; van der Schoor, Sophie R. D.

    2014-01-01

    Amino acids and protein are key factors for growth. The neonatal period requires the highest intake in life to meet the demands. Those demands include amino acids for growth, but proteins and amino acids also function as signalling molecules and function as neurotransmitters. Often the nutritional

  12. Stomach acid test

    Science.gov (United States)

    Gastric acid secretion test ... of the cells in the stomach to release acid. The stomach contents are then removed and analyzed. ... 3.5). These numbers are converted to actual acid production in units of milliequivalents per hour (mEq/ ...

  13. Immunoglobulin and fatty acids

    DEFF Research Database (Denmark)

    2009-01-01

    The present invention relates to a composition comprising 0.1-10 w/w % immunoglobulin (Ig), 4-14 w/w % saturated fatty acids, 4-14 w/w % mono-unsaturated fatty acids and 0-5 w/w % poly-unsaturated fatty acids, wherein the weight percentages are based on the content of dry matter in the composition...

  14. Amino acid analysis

    Science.gov (United States)

    Winitz, M.; Graff, J. (Inventor)

    1974-01-01

    The process and apparatus for qualitative and quantitative analysis of the amino acid content of a biological sample are presented. The sample is deposited on a cation exchange resin and then is washed with suitable solvents. The amino acids and various cations and organic material with a basic function remain on the resin. The resin is eluted with an acid eluant, and the eluate containing the amino acids is transferred to a reaction vessel where the eluant is removed. Final analysis of the purified acylated amino acid esters is accomplished by gas-liquid chromatographic techniques.

  15. Molecular Interaction of Pinic Acid with Sulfuric Acid

    DEFF Research Database (Denmark)

    Elm, Jonas; Kurten, Theo; Bilde, Merete

    2014-01-01

    from the corresponding ΔG values. The first two additions of sulfuric acid to pinic acid are found to be favorable with ΔG values of -9.06 and -10.41 kcal/mol. Addition of a third sulfuric acid molecule is less favorable and leads to a structural rearrangement forming a bridged sulfuric acid-pinic acid...... without the further possibility for attachment of either sulfuric acid or pinic acid. This suggests that pinic acid cannot be a key species in the first steps in nucleation, but the favorable interactions between sulfuric acid and pinic acid imply that pinic acid can contribute to the subsequent growth...

  16. Tryptophan-Derived 3-Hydroxyanthranilic Acid Contributes to Angiotensin II-Induced Abdominal Aortic Aneurysm Formation in Mice In Vivo.

    Science.gov (United States)

    Wang, Qiongxin; Ding, Ye; Song, Ping; Zhu, Huaiping; Okon, Imoh; Ding, Yang-Nan; Chen, Hou-Zao; Liu, De-Pei; Zou, Ming-Hui

    2017-12-05

    Abnormal amino acid metabolism is associated with vascular disease. However, the causative link between dysregulated tryptophan metabolism and abdominal aortic aneurysm (AAA) is unknown. Indoleamine 2,3-dioxygenase (IDO) is the first and rate-limiting enzyme in the kynurenine pathway of tryptophan metabolism. Mice with deficiencies in both apolipoprotein e (Apoe) and IDO (Apoe -/- /IDO -/- ) were generated by cross-breeding IDO -/- mice with Apoe -/- mice. The acute infusion of angiotensin II markedly increased the incidence of AAA in Apoe -/- mice, but not in Apoe -/- /IDO -/- mice, which presented decreased elastic lamina degradation and aortic expansion. These features were not altered by the reconstitution of bone marrow cells from IDO +/+ mice. Moreover, angiotensin II infusion instigated interferon-γ, which induced the expression of IDO and kynureninase and increased 3-hydroxyanthranilic acid (3-HAA) levels in the plasma and aortas of Apoe -/- mice, but not in IDO -/- mice. Both IDO and kynureninase controlled the production of 3-HAA in vascular smooth muscle cells. 3-HAA upregulated matrix metallopeptidase 2 via transcription factor nuclear factor-κB. Furthermore, kynureninase knockdown in mice restrained 3-HAA, matrix metallopeptidase 2, and resultant AAA formation by angiotensin II infusion. Intraperitoneal injections of 3-HAA into Apoe -/- and Apoe -/- /IDO -/- mice for 6 weeks increased the expression and activity of matrix metallopeptidase 2 in aortas without affecting metabolic parameters. Finally, human AAA samples had stronger staining with the antibodies against 3-HAA, IDO, and kynureninase than those in adjacent nonaneurysmal aortic sections of human AAA samples. These data define a previously undescribed causative role for 3-HAA, which is a product of tryptophan metabolism, in AAA formation. Furthermore, these findings suggest that 3-HAA reduction may be a new target for treating cardiovascular diseases. © 2017 American Heart Association, Inc.

  17. Abscisic acid metabolism and anthocyanin synthesis in grape skin are affected by light emitting diode (LED) irradiation at night.

    Science.gov (United States)

    Kondo, Satoru; Tomiyama, Hiroyuki; Rodyoung, Abhichartbut; Okawa, Katsuya; Ohara, Hitoshi; Sugaya, Sumiko; Terahara, Norihiko; Hirai, Nobuhiro

    2014-06-15

    The effects of blue and red light irradiation at night on abscisic acid (ABA) metabolism and anthocyanin synthesis were examined in grape berries. The expressions of VlMYBA1-2, VlMYBA2, UDP-glucose-flavonoid 3-O-glucosyltransferase (VvUFGT), 9-cis-epoxycarotenoid dioxygenase (VvNCED1), and ABA 8'-hydroxylase (VvCYP707A1) were also investigated. Endogenous ABA, its metabolite phaseic acid (PA), and the expressions of VvNCED1 and VvCYP707A1 were highest in red light-emitting diode (LED)-treated skin. In contrast, anthocyanin concentrations were highest in blue LED-treated skin, followed by red LED treatment. However, the expressions of VlMYBA1-2, VlMYBA2, and VvUFGT did not necessarily coincide with anthocyanin concentrations. The quality of coloring may depend on the amount of malvidin-based anthocyanin, which increased toward harvest in blue and red LED-treated skin, unlike in untreated controls. An increase in sugars was also observed in blue and red LED-treated skin. These results suggest that blue LED irradiation at night may be effective in increasing anthocyanin and sugar concentrations in grape berries. However, there is evidence that another factor may influence anthocyanin concentrations in grape berry skin significantly more than endogenous ABA: ABA concentrations were highest in red LED-treated skin, which had lower anthocyanin concentrations than blue LED-treated skin. Copyright © 2014 Elsevier GmbH. All rights reserved.

  18. Employing a Recombinant Strain of Advenella mimigardefordensis for Biotechnical Production of Homopolythioesters from 3,3′-Dithiodipropionic Acid

    Science.gov (United States)

    Xia, Yongzhen; Wübbeler, Jan Hendrik; Qi, Qingsheng

    2012-01-01

    Advenella mimigardefordensis strain DPN7T was genetically modified to produce poly(3-mercaptopropionic acid) (PMP) homopolymer by exploiting the recently unraveled process of 3,3′-dithiodipropionic acid (DTDP) catabolism. Production was achieved by systematically engineering the metabolism of this strain as follows: (i) deletion of its inherent 3MP dioxygenase-encoding gene (mdo), (ii) introduction of the buk-ptb operon (genes encoding the butyrate kinase, Buk, and the phosphotransbutyrylase, Ptb, from Clostridium acetobutylicum), and (iii) overexpression of its own polyhydroxyalkanoate synthase (phaCAm). These measures yielded the potent PMP production strain A. mimigardefordensis strain SHX22. The deletion of mdo was required for adequate synthesis of PMP due to the resulting accumulation of 3MP during utilization of DTDP. Overexpression of the plasmid-borne buk-ptb operon caused a severe growth repression. This effect was overcome by inserting this operon into the genome. Polyhydroxyalkanoate (PHA) synthases from different origins were compared. The native PHA synthase of A. mimigardefordensis (phaCAm) was obviously the best choice to establish homopolythioester production in this strain. In addition, the cultivation conditions, including an appropriate provision of the carbon source, were further optimized to enhance PMP production. The engineered strain accumulated PMP up to approximately 25% (wt/wt) of the cell dry weight when cultivated in mineral salts medium containing glycerol as the carbon source in addition to DTDP as the sulfur-providing precursor. According to our knowledge, this is the first report of PMP homopolymer production by a metabolically engineered bacterium using DTDP, which is nontoxic, as the precursor substrate. PMID:22344658

  19. [Biosynthesis of adipic acid].

    Science.gov (United States)

    Han, Li; Chen, Wujiu; Yuan, Fei; Zhang, Yuanyuan; Wang, Qinhong; Ma, Yanhe

    2013-10-01

    Adipic acid is a six-carbon dicarboxylic acid, mainly for the production of polymers such as nylon, chemical fiber and engineering plastics. Its annual demand is close to 3 million tons worldwide. Currently, the industrial production of adipic acid is based on the oxidation of aromatics from non-renewable petroleum resources by chemo-catalytic processes. It is heavily polluted and unsustainable, and the possible alternative method for adipic acid production should be developed. In the past years, with the development of synthetic biology and metabolic engineering, green and clean biotechnological methods for adipic acid production attracted more attention. In this study, the research advances of adipic acid and its precursor production are reviewed, followed by addressing the perspective of the possible new pathways for adipic acid production.

  20. Process for the preparation of lactic acid and glyceric acid

    Science.gov (United States)

    Jackson, James E [Haslett, MI; Miller, Dennis J [Okemos, MI; Marincean, Simona [Dewitt, MI

    2008-12-02

    Hexose and pentose monosaccharides are degraded to lactic acid and glyceric acid in an aqueous solution in the presence of an excess of a strongly anionic exchange resin, such as AMBERLITE IRN78 and AMBERLITE IRA400. The glyceric acid and lactic acid can be separated from the aqueous solution. Lactic acid and glyceric acid are staple articles of commerce.

  1. Bile acid sequestrants

    DEFF Research Database (Denmark)

    Hansen, Morten; Sonne, David P; Knop, Filip K

    2014-01-01

    Bile acids are synthesized in the liver from cholesterol and have traditionally been recognized for their role in absorption of lipids and in cholesterol homeostasis. In recent years, however, bile acids have emerged as metabolic signaling molecules that are involved in the regulation of lipid...... and glucose metabolism, and possibly energy homeostasis, through activation of the bile acid receptors farnesoid X receptor (FXR) and TGR5. Bile acid sequestrants (BASs) constitute a class of drugs that bind bile acids in the intestine to form a nonabsorbable complex resulting in interruption...... of the enterohepatic circulation. This increases bile acid synthesis and consequently reduces serum low-density lipoprotein cholesterol. Also, BASs improve glycemic control in patients with type 2 diabetes. Despite a growing understanding of the impact of BASs on glucose metabolism, the mechanisms behind their glucose...

  2. Citric Acid Alternative to Nitric Acid Passivation

    Science.gov (United States)

    Lewis, Pattie L. (Compiler)

    2013-01-01

    The Ground Systems Development and Operations GSDO) Program at NASA John F. Kennedy Space Center (KSC) has the primary objective of modernizing and transforming the launch and range complex at KSC to benefit current and future NASA programs along with other emerging users. Described as the launch support and infrastructure modernization program in the NASA Authorization Act of 2010, the GSDO Program will develop and implement shared infrastructure and process improvements to provide more flexible, affordable, and responsive capabilities to a multi-user community. In support of the GSDO Program, the purpose of this project is to demonstratevalidate citric acid as a passivation agent for stainless steel. Successful completion of this project will result in citric acid being qualified for use as an environmentally preferable alternative to nitric acid for passivation of stainless steel alloys in NASA and DoD applications.

  3. DEOXYRIBONUCLEIC ACID HYBRIDS OF ACETIC ACID BACTERIA

    Science.gov (United States)

    De Ley, J.; Friedman, S.

    1964-01-01

    De Ley, J. (State University, Ghent, Belgium), and S. Friedman. Deoxyribonucleic acid hybrids of acetic acid bacteria. J. Bacteriol. 88:937–945. 1964.—Deuterated N15-labeled deoxyribonucleic acid (DNA) from Acetobacter aceti (mesoxydans 4) forms hybrids with ordinary DNA from other species of this genus (A. xylinum, A. pasteurianus, A. estunensis, and possibly A. xylinoides) when the guanine plus cytosine base composition does not vary by more than 1 to 2%. Beyond this limit (A. aceti Ch31 and A. muciparus 5) no hybrids are formed. The hybrids are apparently derived from an asymmetrical part of the compositional distribution. The results lend strength to the concept of a genetic species rather than to a division of a genus into sharply separated species, based on small phenotypic differences. Taxonomic implications are discussed. PMID:14219057

  4. Azetidinic amino acids

    DEFF Research Database (Denmark)

    Bräuner-Osborne, Hans; Bunch, Lennart; Chopin, Nathalie

    2005-01-01

    A set of ten azetidinic amino acids, that can be envisioned as C-4 alkyl substituted analogues of trans-2-carboxyazetidine-3-acetic acid (t-CAA) and/or conformationally constrained analogues of (R)- or (S)-glutamic acid (Glu) have been synthesized in a diastereo- and enantiomerically pure form from...... of two diastereoisomers that were easily separated and converted in two steps into azetidinic amino acids. Azetidines 35-44 were characterized in binding studies on native ionotropic Glu receptors and in functional assays at cloned metabotropic receptors mGluR1, 2 and 4, representing group I, II and III...

  5. Recovery of organic acids

    Science.gov (United States)

    Verser, Dan W.; Eggeman, Timothy J.

    2009-10-13

    A method is disclosed for the recovery of an organic acid from a dilute salt solution in which the cation of the salt forms an insoluble carbonate salt. A tertiary amine and CO.sub.2 are introduced to the solution to form the insoluble carbonate salt and a complex between the acid and an amine. A water immiscible solvent, such as an alcohol, is added to extract the acid/amine complex from the dilute salt solution to a reaction phase. The reaction phase is continuously dried and a product between the acid and the solvent, such as an ester, is formed.

  6. The acid rain primer

    International Nuclear Information System (INIS)

    Nugent, O.

    2006-10-01

    Acid rain continues to be a major problem in North America, and particularly in eastern Canada. This report introduced the topic of acid rain and discussed its formation, measurement, sources, and geographic distribution. The major sources of sulphur dioxide in Canada are smelting metals, burning coal for electrical power generation, industrial emissions (e.g., pulp and paper, petroleum and aluminum industry), and oil and gas extraction and refining. In Canada, the largest source of nitrogen oxide is the burning of fossil fuels by the transportation sector. Problem areas for acid rain in Canada were identified. The effects of acid rain were examined on lakes and aquatic ecosystems, forests and soils, human-made structures and materials, human health, and on visibility. Acid rain policies and programs were then presented from a historical and current context. Ecosystem recovery from acid rain was discussed with reference to acid rain monitoring, atmospheric response to reductions in acid-causing emissions, and ecosystem recovery of lakes, forests, and aquatic ecosystems. Challenges affecting ecosystem recovery were also presented. These challenges include drought and dry weather, decrease of base cations in precipitation, release of sulphate previously stored in soil, mineralization and immobilization of sulphur/sulphates. Last, the report discussed what still needs to be done to improve the problem of acid rain as well as future concerns. These concerns include loss of base cations from forested watersheds and nitrogen deposition and saturation. 21 refs., 2 tabs., 17 figs

  7. Folic Acid Quiz

    Science.gov (United States)

    ... to Other Health Outcomes Folic Acid Fortification and Supplementation Neural Tube Defects Surveillance References Data and Statistics Research Birth Defects COUNT Articles & Key Findings Recommendations Links to ...

  8. Recovery of organic acids

    Science.gov (United States)

    Verser, Dan W [Menlo Park, CA; Eggeman, Timothy J [Lakewood, CO

    2011-11-01

    A method is disclosed for the recovery of an organic acid from a dilute salt solution in which the cation of the salt forms an insoluble carbonate salt. A tertiary amine and CO.sub.2 are introduced to the solution to form the insoluble carbonate salt and a complex between the acid and an amine. A water immiscible solvent, such as an alcohol, is added to extract the acid/amine complex from the dilute salt solution to a reaction phase. The reaction phase is continuously dried and a product between the acid and the solvent, such as an ester, is formed.

  9. USGS Tracks Acid Rain

    Science.gov (United States)

    Gordon, John D.; Nilles, Mark A.; Schroder, LeRoy J.

    1995-01-01

    The U.S. Geological Survey (USGS) has been actively studying acid rain for the past 15 years. When scientists learned that acid rain could harm fish, fear of damage to our natural environment from acid rain concerned the American public. Research by USGS scientists and other groups began to show that the processes resulting in acid rain are very complex. Scientists were puzzled by the fact that in some cases it was difficult to demonstrate that the pollution from automobiles and factories was causing streams or lakes to become more acidic. Further experiments showed how the natural ability of many soils to neutralize acids would reduce the effects of acid rain in some locations--at least as long as the neutralizing ability lasted (Young, 1991). The USGS has played a key role in establishing and maintaining the only nationwide network of acid rain monitoring stations. This program is called the National Atmospheric Deposition Program/National Trends Network (NADP/NTN). Each week, at approximately 220 NADP/NTN sites across the country, rain and snow samples are collected for analysis. NADP/NTN site in Montana. The USGS supports about 72 of these sites. The information gained from monitoring the chemistry of our nation's rain and snow is important for testing the results of pollution control laws on acid rain.

  10. Chlorogenic acid and caffeic acid are absorbed in humans

    OpenAIRE

    Olthof, M.R.; Hollman, P.C.H.; Katan, M.B.

    2001-01-01

    Chlorogenic acid, an ester of caffeic acid and quinic acid, is a major phenolic compound in coffee; daily intake in coffee drinkers is 0.5-1 g. Chlorogenic acid and caffeic acid are antioxidants in vitro and might therefore contribute to the prevention of cardiovascular disease. However, data on the absorption of chlorogenic acid and caffeic acid in humans are lacking. We determined the absorption of chlorogenic acid and caffeic acid in a cross-over study with 4 female and 3 male healthy ileo...

  11. Characterization of acid tars

    Energy Technology Data Exchange (ETDEWEB)

    Leonard, Sunday A., E-mail: sunday.leonard@ucl.ac.uk [Department of Civil Environmental and Geomatic Engineering, University College London, Chadwick Building, Gower Street, London, WC1E 6BT (United Kingdom); Stegemann, Julia A. [Department of Civil Environmental and Geomatic Engineering, University College London, Chadwick Building, Gower Street, London, WC1E 6BT (United Kingdom); Roy, Amitava [J. Bennett Johnston, Sr., Centre for Advance Microstructures and Devices (CAMD), 6980 Jefferson Highway, Louisiana State University, Baton Rouge, LA, 70806 (United States)

    2010-03-15

    Acid tars from the processing of petroleum and petrochemicals using sulfuric acid were characterized by gas chromatography/mass spectrometry (GC/MS), inductively coupled plasma/optical emission spectrometry (ICP/OES), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectrometry, and scanning electron microscopy/energy dispersive X-ray (SEM/EDX) micro-analysis. Leaching of contaminants from the acid tars in 48 h batch tests with distilled water at a liquid-to-solid ratio 10:1 was also studied. GC/MS results show that the samples contained aliphatic hydrocarbons, cyclic hydrocarbons, up to 12 of the 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs), and numerous other organic groups, including organic acids (sulfonic acids, carboxylic acids and aromatic acids), phenyl, nitrile, amide, furans, thiophenes, pyrroles, and phthalates, many of which are toxic. Metals analysis shows that Pb was present in significant concentration. DSC results show different transition peaks in the studied samples, demonstrating their complexity and variability. FTIR analysis further confirmed the presence of the organic groups detected by GC/MS. The SEM/EDX micro-analysis results provided insight on the surface characteristics of the samples and show that contaminants distribution was heterogeneous. The results provide useful data on the composition, complexity, and variability of acid tars; information which hitherto have been scarce in public domain.

  12. Science of acid rain

    International Nuclear Information System (INIS)

    Mizoguchi, Tsuguo

    1992-01-01

    In this report, the mechanism of forming acid rain in the atmosphere and the process of its fall to ground, the mechanism of withering forests by acid substances, and the process of acidifying lakes and marshes are explained. Moreover, the monitoring networks for acid rain and the countermeasures are described. Acid rain is the pollution phenomena related to all environment, that is, atmosphere, hydrosphere, soilsphere, biosphere and so on, and it is a local environmental pollution problem, and at the same time, an international, global environmental pollution problem. In Japan, acid rain has fallen, but the acidification of lakes and marshes is not clear, and the damage to forests is on small scale. However in East Asia region, the release of sulfur oxides and nitrogen oxides is much, and the increase of the effects of acid rain is expected. It is necessary to devise the measures for preventing the damage due to acid rain. The global monitoring networks of World Meteorological Organization and United Nations Environment Program, and those in Europe, USA and Japan are described. The monitoring of acid rain in Japan is behind that in Europe and USA. (K.I.)

  13. Omega-3 Fatty Acids

    Science.gov (United States)

    Omega-3 fatty acids are used together with lifestyle changes (diet, weight-loss, exercise) to reduce the amount of triglycerides (a fat- ... in people with very high triglycerides. Omega-3 fatty acids are in a class of medications called antilipemic ...

  14. Locked nucleic acid

    DEFF Research Database (Denmark)

    Jepsen, Jan Stenvang; Sørensen, Mads D; Wengel, Jesper

    2004-01-01

    Locked nucleic acid (LNA) is a class of nucleic acid analogs possessing very high affinity and excellent specificity toward complementary DNA and RNA, and LNA oligonucleotides have been applied as antisense molecules both in vitro and in vivo. In this review, we briefly describe the basic...

  15. Peptide Nucleic Acid Synthons

    DEFF Research Database (Denmark)

    2004-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  16. Amino Acid Crossword Puzzle

    Science.gov (United States)

    Sims, Paul A.

    2011-01-01

    Learning the 20 standard amino acids is an essential component of an introductory course in biochemistry. Later in the course, the students study metabolism and learn about various catabolic and anabolic pathways involving amino acids. Learning new material or concepts often is easier if one can connect the new material to what one already knows;…

  17. Halogenated fatty acids

    DEFF Research Database (Denmark)

    Mu, Huiling; Wesén, Clas; Sundin, Peter

    1997-01-01

    Chlorinated fatty acids have been found to be major contributors to organohalogen compounds in fish, bivalves, jellyfish, and lobster, and they have been indicated to contribute considerably to organohalogens in marine mammals. Brominated fatty acids have been found in marine sponges. Also, chlor...

  18. Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    2003-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  19. Peptide Nucleic Acids (PNA)

    DEFF Research Database (Denmark)

    2002-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  20. Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    1998-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  1. Acid dissociation characteristics of humic acids

    International Nuclear Information System (INIS)

    Tochiyama, Osamu; Sakakibara, Tetsuro; Inoue, Yasushi

    1995-01-01

    Based on the results from potentiometric titrations carried out on polyacrylic acid and some commercially available humic acids, the equation for the proton dissociation of weak polymeric acids is proposed to be K app (H + )α/(1-α) = K 1/2 {(1-α)/α}((Na + )/(Na + ) s ), where α is the degree of dissociation, K 1/2 is the dissociation constant at α = 1/2, and the brackets with subscript s denote the concentration at the surface of the polymer. This equation has been derived on the assumptions: (i) Each polymer molecule is a polybasic acid (H N R N ) having different acidic sites with K values from K 1 to K N . (ii) Binding energies of protons on these sites are all equal. (iii) The ratios of the dissociation constants of H N-i R N i- and H N-j R N j- is expressed by K i /K j = {(N-i+1)/i}/{(N-j+1)/j} since the probabilities to release or bind a proton are proportional to the numbers of protons or numbers of available anionic sites on the polymer. (iv) The effective concentration of protons at the surface of the polymer ((H + ) s ) is related by (H + ) s /(H + ) = (Na + ) s /(Na + ), where (Na + ) s can be estimated by the relation, (Na + ) s = (Cl - ) s + (R - ) s (where (R - ) s Σi(H N-i R N i- )). This leads to (Na + ) s ≅ (Cl - ) s , which in turn leads to (Na + ) s ≅ (Na + ) at high ionic strength and (Na + ) s ≅ (R - ) s = C R α at low ionic strength. (author)

  2. Chlorogenic acid and caffeic acid are absorbed in humans

    NARCIS (Netherlands)

    Olthof, Margreet R.; Hollman, Peter C H; Katan, Martijn B.

    2001-01-01

    Chlorogenic acid, an ester of caffeic acid and quinic acid, is a major phenolic compound in coffee; daily intake in coffee drinkers is 0.5-1 g. Chlorogenic acid and caffeic acid are antioxidants in vitro and might therefore contribute to the prevention of cardiovascular disease. However, data on the

  3. Production of shikimic acid.

    Science.gov (United States)

    Ghosh, Saptarshi; Chisti, Yusuf; Banerjee, Uttam C

    2012-01-01

    Shikimic acid is a key intermediate for the synthesis of the antiviral drug oseltamivir (Tamiflu®). Shikimic acid can be produced via chemical synthesis, microbial fermentation and extraction from certain plants. An alternative production route is via biotransformation of the more readily available quinic acid. Much of the current supply of shikimic acid is sourced from the seeds of Chinese star anise (Illicium verum). Supply from star anise seeds has experienced difficulties and is susceptible to vagaries of weather. Star anise tree takes around six-years from planting to bear fruit, but remains productive for long. Extraction and purification from seeds are expensive. Production via fermentation is increasing. Other production methods are too expensive, or insufficiently developed. In the future, production in recombinant microorganisms via fermentation may become established as the preferred route. Methods for producing shikimic acid are reviewed. Copyright © 2012 Elsevier Inc. All rights reserved.

  4. 2-Methylaspartic acid monohydrate

    Directory of Open Access Journals (Sweden)

    Ray J. Butcher

    2013-12-01

    Full Text Available The title compound, C5H9NO4·H2O, is an isomer of the α-amino acid glutamic acid that crystallizes from water in its zwitterionic form as a monohydrate. It is not one of the 20 proteinogenic α-amino acids that are used in living systems and differs from the natural amino acids in that it has an α-methyl group rather than an α-H atom. In the crystal, an O—H...O hydrogen bond is present between the acid and water molecules while extensive N—H...O and O—H...O hydrogen bonds link the components into a three-dimensional array.

  5. Acidity in rainfall

    International Nuclear Information System (INIS)

    Tisue, G.T.; Kacoyannakis, J.

    1975-01-01

    The reported increasing acidity of rainfall raises many interesting ecological and chemical questions. In spite of extensive studies in Europe and North America there are, for example, great uncertainties in the relative contributions of strong and weak acids to the acid-base properties of rainwater. Unravelling this and similar problems may require even more rigorous sample collection and analytical procedures than previously employed. Careful analysis of titration curves permits inferences to be made regarding chemical composition, the possible response of rainwater to further inputs of acidic components to the atmosphere, and the behavior to be expected when rainwater interacts with the buffers present in biological materials and natural waters. Rainwater samples collected during several precipitation events at Argonne National Laboratory during October and November 1975 have been analyzed for pH, acid and base neutralizing properties, and the ions of ammonium, nitrate, chloride, sulfate, and calcium. The results are tabulated

  6. Conjugated Fatty Acid Synthesis

    Science.gov (United States)

    Rawat, Richa; Yu, Xiao-Hong; Sweet, Marie; Shanklin, John

    2012-01-01

    Conjugated linolenic acids (CLNs), 18:3 Δ9,11,13, lack the methylene groups found between the double bonds of linolenic acid (18:3 Δ9,12,15). CLNs are produced by conjugase enzymes that are homologs of the oleate desaturases FAD2. The goal of this study was to map the domain(s) within the Momordica charantia conjugase (FADX) responsible for CLN formation. To achieve this, a series of Momordica FADX-Arabidopsis FAD2 chimeras were expressed in the Arabidopsis fad3fae1 mutant, and the transformed seeds were analyzed for the accumulation of CLN. These experiments identified helix 2 and the first histidine box as a determinant of conjugase product partitioning into punicic acid (18:3 Δ9cis,11trans,13cis) or α-eleostearic acid (18:3 Δ9cis,11trans,13trans). This was confirmed by analysis of a FADX mutant containing six substitutions in which the sequence of helix 2 and first histidine box was converted to that of FAD2. Each of the six FAD2 substitutions was individually converted back to the FADX equivalent identifying residues 111 and 115, adjacent to the first histidine box, as key determinants of conjugase product partitioning. Additionally, expression of FADX G111V and FADX G111V/D115E resulted in an approximate doubling of eleostearic acid accumulation to 20.4% and 21.2%, respectively, compared with 9.9% upon expression of the native Momordica FADX. Like the Momordica conjugase, FADX G111V and FADX D115E produced predominantly α-eleostearic acid and little punicic acid, but the FADX G111V/D115E double mutant produced approximately equal amounts of α-eleostearic acid and its isomer, punicic acid, implicating an interactive effect of residues 111 and 115 in punicic acid formation. PMID:22451660

  7. Trans Fatty Acids

    Science.gov (United States)

    Doyle, Ellin

    1997-09-01

    Fats and their various fatty acid components seem to be a perennial concern of nutritionists and persons concerned with healthful diets. Advice on the consumption of saturated, polyunsaturated, monounsaturated, and total fat bombards us from magazines and newspapers. One of the newer players in this field is the group of trans fatty acids found predominantly in partially hydrogenated fats such as margarines and cooking fats. The controversy concerning dietary trans fatty acids was recently addressed in an American Heart Association (AHA) science advisory (1) and in a position paper from the American Society of Clinical Nutrition/American Institute of Nutrition (ASCN/AIN) (2). Both reports emphasize that the best preventive strategy for reducing risk for cardiovascular disease and some types of cancer is a reduction in total and saturated fats in the diet, but a reduction in the intake of trans fatty acids was also recommended. Although the actual health effects of trans fatty acids remain uncertain, experimental evidence indicates that consumption of trans fatty acids adversely affects serum lipid levels. Since elevated levels of serum cholesterol and triacylglycerols are associated with increased risk of cardiovascular disease, it follows that intake of trans fatty acids should be minimized.

  8. Sulfuric Acid on Europa

    Science.gov (United States)

    1999-01-01

    Frozen sulfuric acid on Jupiter's moon Europa is depicted in this image produced from data gathered by NASA's Galileo spacecraft. The brightest areas, where the yellow is most intense, represent regions of high frozen sulfuric acid concentration. Sulfuric acid is found in battery acid and in Earth's acid rain. This image is based on data gathered by Galileo's near infrared mapping spectrometer.Europa's leading hemisphere is toward the bottom right, and there are enhanced concentrations of sulfuric acid in the trailing side of Europa (the upper left side of the image). This is the face of Europa that is struck by sulfur ions coming from Jupiter's innermost moon, Io. The long, narrow features that crisscross Europa also show sulfuric acid that may be from sulfurous material extruded in cracks. Galileo, launched in 1989, has been orbiting Jupiter and its moons since December 1995. JPL manages the Galileo mission for NASA's Office of Space Science, Washington DC. JPL is a division of the California Institute of Technology, Pasadena, CA.

  9. Glycosyltransferase glycosylating flavokermesic acid and/or kermesic acid

    DEFF Research Database (Denmark)

    2016-01-01

    An isolated glycosyltransferase (GT) polypeptide capable of: (I) : conjugating glucose to flavokermesic acid (FK); and/or (II) : conjugating glucose to kermesic acid (KA) and use of this GT to e.g. make Carminic acid.......An isolated glycosyltransferase (GT) polypeptide capable of: (I) : conjugating glucose to flavokermesic acid (FK); and/or (II) : conjugating glucose to kermesic acid (KA) and use of this GT to e.g. make Carminic acid....

  10. GLYCOSYLTRANSFERASE GLYCOSYLATING FLAVOKERMESIC ACID AND/OR KERMESIC ACID

    DEFF Research Database (Denmark)

    2015-01-01

    An isolated glycosyltransferase (GT) polypeptide capable of: (I): conjugating glucose to flavokermesic acid (FK); and/or (II): conjugating glucose to kermesic acid (KA) and use of this GT to e.g. make Carminic acid.......An isolated glycosyltransferase (GT) polypeptide capable of: (I): conjugating glucose to flavokermesic acid (FK); and/or (II): conjugating glucose to kermesic acid (KA) and use of this GT to e.g. make Carminic acid....

  11. Fusidic acid in dermatology

    DEFF Research Database (Denmark)

    Schöfer, Helmut; Simonsen, Lene

    1995-01-01

    Studies on the clinical efficacy of fusidic acid in skin and soft-tissue infections (SSTIs), notably those due to Staphylococcus aureus, are reviewed. Oral fusidic acid (tablets dosed at 250 mg twice daily, or a suspension for paediatric use at 20 mg/kg/day given as two daily doses) has shown good...... excellent results in infected eczema by addressing both inflammation and infection. A new lipid-rich combination formulation provides an extra moisturizing effect. Development of resistance to fusidic acid has remained generally low or short-lived and can be minimized by restricting therapy to no more than...

  12. octadecenoic acid in tomato

    African Journals Online (AJOL)

    User

    octadecenoic acid which is proba- bly involved in plant defense responses is synthesized in tomato fruits and subjected to metabo- lism. Its catabolism or conversion was thus further characterized. The endogenous level of.

  13. Folic acid in diet

    Science.gov (United States)

    Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes: Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. National Academies Press. Washington, DC, 1998. PMID: 23193625 ...

  14. Amino Acids and Chirality

    Science.gov (United States)

    Cook, Jamie E.

    2012-01-01

    Amino acids are among the most heavily studied organic compound class in carbonaceous chondrites. The abundance, distributions, enantiomeric compositions, and stable isotopic ratios of amino acids have been determined in carbonaceous chondrites fi'om a range of classes and petrographic types, with interesting correlations observed between these properties and the class and typc of the chondritcs. In particular, isomeric distributions appear to correlate with parent bodies (chondrite class). In addition, certain chiral amino acids are found in enantiomeric excess in some chondrites. The delivery of these enantiomeric excesses to the early Earth may have contributed to the origin of the homochirality that is central to life on Earth today. This talk will explore the amino acids in carbonaceous chondritcs and their relevance to the origin of life.

  15. Amino acid racemisation dating

    International Nuclear Information System (INIS)

    Murray-Wallace, C.V.

    1999-01-01

    The potential of the time-dependent amino acid racemisation reaction as a method of age assessment was first reported by Hare and Abelson (1968). They noted that in specimens of the bivalve mollusc Mercenaria sp., greater concentrations of amino acids in the D-configuration with increasing fossil age. Hare and Abelson (1968) also reported negligible racemisation in a modern specimen of Mecanaria sp. On this basis they suggested that the extent of amino acid racemisation (epimerisation in the case of isoleucine) may be used to assess the age of materials within and beyond the range of radiocarbon dating. For the past thirty years amino acid racemisation has been extensively applied in Quaternary research as a method of relative and numeric dating, and a particularly large literature has emerged on the subject

  16. Hydrofluoric acid poisoning

    Science.gov (United States)

    ... mouth (intubation), and breathing machine (ventilator) Blood and urine tests Camera down the throat to see burns in the esophagus and the stomach (endoscopy) Fluids through a vein (IV) Magnesium and calcium solutions to neutralize the acid Medicines ...

  17. Acid Mine Drainage Treatment

    National Research Council Canada - National Science Library

    Fripp, Jon

    2000-01-01

    .... Acid mine drainage (AMD) can have severe impacts to aquatic resources, can stunt terrestrial plant growth and harm wetlands, contaminate groundwater, raise water treatment costs, and damage concrete and metal structures...

  18. Methylmalonic Acid Test

    Science.gov (United States)

    ... and Iron-binding Capacity (TIBC, UIBC) Trichomonas Testing Triglycerides Troponin Tryptase Tumor Markers Uric Acid Urinalysis Urine ... very small amounts and is necessary for human metabolism and energy production. In one step of metabolism, ...

  19. Neutron Nucleic Acid Crystallography.

    Science.gov (United States)

    Chatake, Toshiyuki

    2016-01-01

    The hydration shells surrounding nucleic acids and hydrogen-bonding networks involving water molecules and nucleic acids are essential interactions for the structural stability and function of nucleic acids. Water molecules in the hydration shells influence various conformations of DNA and RNA by specific hydrogen-bonding networks, which often contribute to the chemical reactivity and molecular recognition of nucleic acids. However, X-ray crystallography could not provide a complete description of structural information with respect to hydrogen bonds. Indeed, X-ray crystallography is a powerful tool for determining the locations of water molecules, i.e., the location of the oxygen atom of H2O; however, it is very difficult to determine the orientation of the water molecules, i.e., the orientation of the two hydrogen atoms of H2O, because X-ray scattering from the hydrogen atom is very small.Neutron crystallography is a specialized tool for determining the positions of hydrogen atoms. Neutrons are not diffracted by electrons, but are diffracted by atomic nuclei; accordingly, neutron scattering lengths of hydrogen and its isotopes are comparable to those of non-hydrogen atoms. Therefore, neutron crystallography can determine both of the locations and orientations of water molecules. This chapter describes the current status of neutron nucleic acid crystallographic research as well as the basic principles of neutron diffraction experiments performed on nucleic acid crystals: materials, crystallization, diffraction experiments, and structure determination.

  20. Fatty Acid Biosynthesis IX

    DEFF Research Database (Denmark)

    Carey, E. M.; Hansen, Heinz Johs. Max; Dils, R.

    1972-01-01

    # 1. I. [I-14C]Acetate was covalently bound to rabbit mammary gland fatty acid synthetase by enzymic transacylation from [I-14C]acetyl-CoA. Per mole of enzyme 2 moles of acetate were bound to thiol groups and up to I mole of acetate was bound to non-thiol groups. # 2. 2. The acetyl-fatty acid...... synthetase complex was isolated free from acetyl-CoA. It was rapidly hydrolysed at 30°C, but hydrolysis was greatly diminished at o°C and triacetic lactone synthesis occurred. In the presence of malonyl-CoA and NADPH, all the acetate bound to fatty acid synthetase was incorporated into long-chain fatty acids....... Hydrolysis of bound acetate and incorporation of bound acetate into fatty acids were inhibited to the same extent by guanidine hydrochloride. # 3. 3. Acetate was also covalently bound to fatty acid synthetase by chemical acetylation with [I-14C]acetic anhydride in the absence of CoASH. A total of 60 moles...

  1. [Acids in coffee. XI. The proportion of individual acids in the total titratable acid].

    Science.gov (United States)

    Engelhardt, U H; Maier, H G

    1985-07-01

    22 acids in ground roast coffees and instant coffees were determined by GLC of their silyl derivatives (after preseparation by gel electrophoresis) or isotachophoresis. The contribution to the total acidity (which was estimated by titration to pH 8 after cation exchange of the coffee solutions) was calculated for each individual acid. The mentioned acids contribute with 67% (roast coffee) and 72% (instant coffee) to the total acidity. In the first place citric acid (12.2% in roast coffee/10.7% in instant coffee), acetic acid (11.2%/8.8%) and the high molecular weight acids (8%/9%) contribute to the total acidity. Also to be mentioned are the shares of chlorogenic acids (9%/4.8%), formic acid (5.3%/4.6%), quinic acid (4.7%/5.9%), malic acid (3.9%/3%) and phosphoric acid (2.5%/5.2%). A notable difference in the contribution to total acidity between roast and instant coffee was found for phosphoric acid and pyrrolidonecarboxylic acid (0.7%/1.9%). It can be concluded that those two acids are formed or released from e.g. their esters in higher amounts than other acids during the production of instant coffee.

  2. Acidification and Acid Rain

    Science.gov (United States)

    Norton, S. A.; Veselã½, J.

    2003-12-01

    Air pollution by acids has been known as a problem for centuries (Ducros, 1845; Smith, 1872; Camuffo, 1992; Brimblecombe, 1992). Only in the mid-1900s did it become clear that it was a problem for more than just industrially developed areas, and that precipitation quality can affect aquatic resources ( Gorham, 1955). The last three decades of the twentieth century saw tremendous progress in the documentation of the chemistry of the atmosphere, precipitation, and the systems impacted by acid atmospheric deposition. Chronic acidification of ecosystems results in chemical changes to soil and to surface waters and groundwater as a result of reduction of base cation supply or an increase in acid (H+) supply, or both. The most fundamental changes during chronic acidification are an increase in exchangeable H+ or Al3+ (aluminum) in soils, an increase in H+ activity (˜concentration) in water in contact with soil, and a decrease in alkalinity in waters draining watersheds. Water draining from the soil is acidified and has a lower pH (=-log [H+]). As systems acidify, their biotic community changes.Acidic surface waters occur in many parts of the world as a consequence of natural processes and also due to atmospheric deposition of strong acid (e.g., Canada, Jeffries et al. (1986); the United Kingdom, Evans and Monteith (2001); Sweden, Swedish Environmental Protection Board (1986); Finland, Forsius et al. (1990); Norway, Henriksen et al. (1988a); and the United States (USA), Brakke et al. (1988)). Concern over acidification in the temperate regions of the northern hemisphere has been driven by the potential for accelerating natural acidification by pollution of the atmosphere with acidic or acidifying compounds. Atmospheric pollution ( Figure 1) has resulted in an increased flux of acid to and through ecosystems. Depending on the ability of an ecosystem to neutralize the increased flux of acidity, acidification may increase only imperceptibly or be accelerated at a rate that

  3. Inhibitory effect of ethanol, acetic acid, propionic acid and butyric acid on fermentative hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Bo; Wan, Wei; Wang, Jianlong [Laboratory of Environmental Technology, INET, Tsinghua University, Beijing 100084 (China)

    2008-12-15

    The inhibitory effect of added ethanol, acetic acid, propionic acid and butyric acid on fermentative hydrogen production by mixed cultures was investigated in batch tests using glucose as substrate. The experimental results showed that, at 35 C and initial pH 7.0, during the fermentative hydrogen production, the substrate degradation efficiency, hydrogen production potential, hydrogen yield and hydrogen production rate all trended to decrease with increasing added ethanol, acetic acid, propionic acid and butyric acid concentration from 0 to 300 mmol/L. The inhibitory effect of added ethanol on fermentative hydrogen production was smaller than those of added acetic acid, propionic acid and butyric acid. The modified Han-Levenspiel model could describe the inhibitory effects of added ethanol, acetic acid, propionic acid and butyric acid on fermentative hydrogen production rate in this study successfully. The modified Logistic model could describe the progress of cumulative hydrogen production. (author)

  4. Amino acids in the sedimentary humic and fulvic acids

    Digital Repository Service at National Institute of Oceanography (India)

    Sardessai, S.

    Humic and fulvic acids isolated from a few sediment samples from Arabian Sea and Bay of Bengal were analysed for total hydrolysable amino acids concentration and their composition. The amono acids content of fulvic acids was higher than in the humic...

  5. Synthesis and anticonvulsant activity of novel bicyclic acidic amino acids

    DEFF Research Database (Denmark)

    Conti, Paola; De Amici, Marco; Joppolo Di Ventimiglia, Samuele

    2003-01-01

    Bicyclic acidic amino acids (+/-)-6 and (+/-)-7, which are conformationally constrained homologues of glutamic acid, were prepared via a strategy based on a 1,3-dipolar cycloaddition. The new amino acids were tested toward ionotropic and metabotropic glutamate receptor subtypes; both of them...

  6. Over-expression of LeNCED1 in tomato (Solanum lycopersicum L.) with the rbcS3C promoter allows recovery of lines that accumulate very high levels of abscisic acid and exhibit severe phenotypes.

    Science.gov (United States)

    Tung, Swee Ang; Smeeton, Rachel; White, Charlotte A; Black, Colin R; Taylor, Ian B; Hilton, Howard W; Thompson, Andrew J

    2008-07-01

    Previous work where 9-cis-epoxycarotenoid dioxygenase (NCED) was over-expressed using the constitutive Gelvin Superpromoter resulted in mild increases in abscisic acid (ABA) accumulation, accompanied by stomatal closure and increased water-use efficiency (WUE), but with apparently little impact on long-term biomass production. However, one of the negative effects of the over-expression of NCED using constitutive promoters in tomato was increased seed dormancy. Here we report the use of the rbcS3C promoter, from a gene encoding the small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), to drive LeNCED1 transgene expression in tomato in a light-responsive and circadian manner. In comparison to the constitutive promoter, the rbcS3C promoter allowed the generation of transgenic plants with much higher levels of ABA accumulation in leaves and sap, but the effect on seed dormancy was diminished. These plants displayed the expected reductions in stomatal conductance and CO(2) assimilation, but they also exhibited a severe set of symptoms that included perturbed cotyledon release from the testa, increased photobleaching in young seedlings, substantially reduced chlorophyll and carotenoid content, interveinal leaf flooding, and greatly reduced growth. These symptoms illustrate adverse consequences of long-term, very high ABA accumulation. Only more moderate increases in ABA biosynthesis are likely to be useful in the context of agriculture. Implications are discussed for the design of transgenic 'high ABA' plants that exhibit increased WUE but have minimal negative phenotypic effects.

  7. Amino-acid contamination of aqueous hydrochloric acid.

    Science.gov (United States)

    Wolman, Y.; Miller, S. L.

    1971-01-01

    Considerable amino-acid contamination in commercially available analytical grade hydrochloric acid (37% HCl) was found. One bottle contained 8,300 nmol of amino-acids per liter. A bottle from another supplier contained 6,700 nmol per liter. The contaminants were mostly protein amino-acids and several unknowns. Data on the volatility of the amino-acids during HCl distillation were also obtained.

  8. Domoic Acid Epileptic Disease

    Directory of Open Access Journals (Sweden)

    John S. Ramsdell

    2014-03-01

    Full Text Available Domoic acid epileptic disease is characterized by spontaneous recurrent seizures weeks to months after domoic acid exposure. The potential for this disease was first recognized in a human case study of temporal lobe epilepsy after the 1987 amnesic shellfish-poisoning event in Quebec, and was characterized as a chronic epileptic syndrome in California sea lions through investigation of a series of domoic acid poisoning cases between 1998 and 2006. The sea lion study provided a breadth of insight into clinical presentations, unusual behaviors, brain pathology, and epidemiology. A rat model that replicates key observations of the chronic epileptic syndrome in sea lions has been applied to identify the progression of the epileptic disease state, its relationship to behavioral manifestations, and to define the neural systems involved in these behavioral disorders. Here, we present the concept of domoic acid epileptic disease as a delayed manifestation of domoic acid poisoning and review the state of knowledge for this disease state in affected humans and sea lions. We discuss causative mechanisms and neural underpinnings of disease maturation revealed by the rat model to present the concept for olfactory origin of an epileptic disease; triggered in dendodendritic synapases of the olfactory bulb and maturing in the olfactory cortex. We conclude with updated information on populations at risk, medical diagnosis, treatment, and prognosis.

  9. Biodegradation of Cyanuric Acid

    Science.gov (United States)

    Saldick, Jerome

    1974-01-01

    Cyanuric acid biodegrades readily under a wide variety of natural conditions, and particularly well in systems of either low or zero dissolved-oxygen level, such as anaerobic activated sludge and sewage, soils, muds, and muddy streams and river waters, as well as ordinary aerated activated sludge systems with typically low (1 to 3 ppm) dissolved-oxygen levels. Degradation also proceeds in 3.5% sodium chloride solution. Consequently, there are degradation pathways widely available for breaking down cyanuric acid discharged in domestic effluents. The overall degradation reaction is merely a hydrolysis; CO2 and ammonia are the initial hydrolytic breakdown products. Since no net oxidation occurs during this breakdown, biodegradation of cyanuric acid exerts no primary biological oxygen demand. However, eventual nitrification of the ammonia released will exert its usual biological oxygen demand. PMID:4451360

  10. Acid rain in Asia

    Science.gov (United States)

    Bhatti, Neeloo; Streets, David G.; Foell, Wesley K.

    1992-07-01

    Acid rain has been an issue of great concern in North America and Europe during the past several decades. However, due to the passage of a number of recent regulations, most notably the Clean Air Act in the United States in 1990, there is an emerging perception that the problem in these Western nations is nearing solution. The situation in the developing world, particularly in Asia, is much bleaker. Given the policies of many Asian nations to achieve levels of development comparable with the industrialized world—which necessitate a significant expansion of energy consumption (most derived from indigenous coal reserves)—the potential for the formation of, and damage from, acid deposition in these developing countries is very high. This article delineates and assesses the emissions patterns, meteorology, physical geology, and biological and cultural resources present in various Asian nations. Based on this analysis and the risk factors to acidification, it is concluded that a number of areas in Asia are currently vulnerable to acid rain. These regions include Japan, North and South Korea, southern China, and the mountainous portions of Southeast Asia and southwestern India. Furthermore, with accelerated development (and its attendant increase in energy use and production of emissions of acid deposition precursors) in many nations of Asia, it is likely that other regions will also be affected by acidification in the near future. Based on the results of this overview, it is clear that acid deposition has significant potential to impact the Asian region. However, empirical evidence is urgently needed to confirm this and to provide early warning of increases in the magnitude and spread of acid deposition and its effects throughout this part of the world.

  11. Whither Acid Rain?

    Directory of Open Access Journals (Sweden)

    Peter Brimblecombe

    2000-01-01

    Full Text Available Acid rain, the environmental cause célèbre of the 1980s seems to have vanished from popular conscience. By contrast, scientific research, despite funding difficulties, has continued to produce hundreds of research papers each year. Studies of acid rain taught much about precipitation chemistry, the behaviour of snow packs, long-range transport of pollutants and new issues in the biology of fish and forested ecosystems. There is now evidence of a shift away from research in precipitation and sulfur chemistry, but an impressive theoretical base remains as a legacy.

  12. 2-(Benzylcarbamoylnicotinic acid

    Directory of Open Access Journals (Sweden)

    Yan-Cao Mao

    2013-10-01

    Full Text Available In the title compound, C14H12N2O3, the pyridine ring is twisted with respect to the phenyl ring and the carboxylic acid group at angles of 37.1 (5 and 8.1 (3°, respectively; the phenyl ring forms a dihedral angle of 41.4 (1° with the mean plane of the C—NH—C=O fragment. An intramolecular O—H...O hydrogen bond occurs between the carboxylic acid and carbonyl groups. In the crystal, N—H...O hydrogen bonds link molecules into a supramolecular chain running along the a-axis direction.

  13. Boric acid concentration monitoring

    International Nuclear Information System (INIS)

    Kysela, J.; Mickal, V.; Racek, J.

    1978-01-01

    Boric acid concentration was measured by thermal neutron absorption in the study of the boric acid sorption and desorption curves on an anion exchange resin. Ra-Be 18.5 GBq and Am-Be 111 GBq sources and water as a moderator were used. The SNM 12 cylindrical corona detector with 10 B placed in the middle of the measuring cell was used for neutron flux measurement. The HP 9600 E computer system was used for measured data collection and evaluation. (Ha)

  14. Omega-3 fatty acids: new insights into the pharmacology and biology of docosahexaenoic acid, docosapentaenoic acid, and eicosapentaenoic acid.

    Science.gov (United States)

    Davidson, Michael H

    2013-12-01

    Fish oil contains a complex mixture of omega-3 fatty acids, which are predominantly eicosapentaenoic acid (EPA), docosapentaenoic acid, and docosahexaenoic acid (DHA). Each of these omega-3 fatty acids has distinct biological effects that may have variable clinical effects. In addition, plasma levels of omega-3 fatty acids are affected not only by dietary intake, but also by the polymorphisms of coding genes fatty acid desaturase 1-3 for the desaturase enzymes that convert short-chain polyunsaturated fatty acids to long-chain polyunsaturated fatty acids. The clinical significance of this new understanding regarding the complexity of omega-3 fatty acid biology is the purpose of this review. FADS polymorphisms that result in either lower levels of long-chain omega-3 fatty acids or higher levels of long-chain omega-6 polyunsaturated fatty acids, such as arachidonic acid, are associated with dyslipidemia and other cardiovascular risk factors. EPA and DHA have differences in their effects on lipoprotein metabolism, in which EPA, with a more potent peroxisome proliferator-activated receptor-alpha effect, decreases hepatic lipogenesis, whereas DHA not only enhances VLDL lipolysis, resulting in greater conversion to LDL, but also increases HDL cholesterol and larger, more buoyant LDL particles. Overall, these results emphasize that blood concentrations of individual long-chain polyunsaturated fatty acids, which reflect both dietary intake and metabolic influences, may have independent, but also complementary- biological effects and reinforce the need to potentially provide a complex mixture of omega-3 fatty acids to maximize cardiovascular risk reduction.

  15. Catalytic acetoxylation of lactic acid to 2-acetoxypropionic acid, en route to acrylic acid

    NARCIS (Netherlands)

    Beerthuis, R.; Granollers, M.; Brown, D.R.; Salavagione, H.J.; Rothenberg, G.; Shiju, N.R.

    2015-01-01

    We present an alternative synthetic route to acrylic acid, starting from the platform chemical lactic acid and using heterogeneous catalysis. To improve selectivity, we designed an indirect dehydration reaction that proceeds via acetoxylation of lactic acid to 2-acetoxypropionic acid. This

  16. The Acid-Base Titration of a Very Weak Acid: Boric Acid

    Science.gov (United States)

    Celeste, M.; Azevedo, C.; Cavaleiro, Ana M. V.

    2012-01-01

    A laboratory experiment based on the titration of boric acid with strong base in the presence of d-mannitol is described. Boric acid is a very weak acid and direct titration with NaOH is not possible. An auxiliary reagent that contributes to the release of protons in a known stoichiometry facilitates the acid-base titration. Students obtain the…

  17. Usnic acid controls the acidity tolerance of lichens

    International Nuclear Information System (INIS)

    Hauck, Markus; Juergens, Sascha-Rene

    2008-01-01

    The hypotheses were tested that, firstly, lichens producing the dibenzofuran usnic acid colonize substrates characterized by specific pH ranges, secondly, this preferred pH is in a range where soluble usnic acid and its corresponding anion occur in similar concentrations, and thirdly, usnic acid makes lichens vulnerable to acidity. Lichens with usnic acid prefer an ambient pH range between 3.5 and 5.5 with an optimum between 4.0 and 4.5. This optimum is close to the pK a1 value of usnic acid of 4.4. Below this optimum pH, dissolved SO 2 reduces the chlorophyll fluorescence yield more in lichens with than without their natural content of usnic acid. This suggests that usnic acid influences the acidity tolerance of lichens. The putative mechanism of the limited acidity tolerance of usnic acid-containing lichens is the acidification of the cytosol by molecules of protonated usnic acid shuttling protons through the plasma membrane at an apoplastic pH a1 . - Combined field and experimental data suggest that usnic acid makes lichens sensitive to acidity at pH <3.5

  18. Oxalic acid excretion after intravenous ascorbic acid administration

    Science.gov (United States)

    Robitaille, Line; Mamer, Orval A.; Miller, Wilson H.; Levine, Mark; Assouline, Sarit; Melnychuk, David; Rousseau, Caroline; Hoffer, L. John

    2012-01-01

    Ascorbic acid is frequently administered intravenously by alternative health practitioners and, occasionally, by mainstream physicians. Intravenous administration can greatly increase the amount of ascorbic acid that reaches the circulation, potentially increasing the risk of oxalate crystallization in the urinary space. To investigate this possibility, we developed gas chromatography mass spectrometry methodology and sampling and storage procedures for oxalic acid analysis without interference from ascorbic acid and measured urinary oxalic acid excretion in people administered intravenous ascorbic acid in doses ranging from 0.2 to 1.5 g/kg body weight. In vitro oxidation of ascorbic acid to oxalic acid did not occur when urine samples were brought immediately to pH less than 2 and stored at –30°C within 6 hours. Even very high ascorbic acid concentrations did not interfere with the analysis when oxalic acid extraction was carried out at pH 1. As measured during and over the 6 hours after ascorbic acid infusions, urinary oxalic acid excretion increased with increasing doses, reaching approximately 80 mg at a dose of approximately 100 g. We conclude that, when studied using correct procedures for sample handling, storage, and analysis, less than 0.5% of a very large intravenous dose of ascorbic acid is recovered as urinary oxalic acid in people with normal renal function. PMID:19154961

  19. Comparison of Buffer Effect of Different Acids During Sandstone Acidizing

    International Nuclear Information System (INIS)

    Shafiq, Mian Umer; Mahmud, Hisham Khaled Ben; Hamid, Mohamed Ali

    2015-01-01

    The most important concern of sandstone matrix acidizing is to increase the formation permeability by removing the silica particles. To accomplish this, the mud acid (HF: HCl) has been utilized successfully for many years to stimulate the sandstone formations, but still it has many complexities. This paper presents the results of laboratory investigations of different acid combinations (HF: HCl, HF: H 3 PO 4 and HF: HCOOH). Hydrofluoric acid and fluoboric acid are used to dissolve clays and feldspar. Phosphoric and formic acids are added as a buffer to maintain the pH of the solution; also it allows the maximum penetration of acid into the core sample. Different tests have been performed on the core samples before and after the acidizing to do the comparative study on the buffer effect of these acids. The analysis consists of permeability, porosity, color change and pH value tests. There is more increase in permeability and porosity while less change in pH when phosphoric and formic acids were used compared to mud acid. From these results it has been found that the buffer effect of phosphoric acid and formic acid is better than hydrochloric acid. (paper)

  20. Detection of meta- and ortho-cleavage dioxygenases in bacterial ...

    African Journals Online (AJOL)

    DR. MIKE HORSFALL

    was defined as the initial rate of indigo formation or enzyme specific activity normalized to the protein content of the sample. ... One unit of activity was defined as the amount of enzyme catalyzing the oxidation of 1 mmol NADH min .... degrade hydrocarbons. These can easily allow the formation of new mixed metabolic ...

  1. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Catechol 1,2-dioxygenase (CTD) and protocatechuate 3,4-dioxygenase (PCD) are bacterial non-heme iron enzymes, which catalyse the oxidative cleavage of catechols to cis, cis-muconic acids with the incorporation of molecular oxygen via a mechanism involving a high-spin ferric centre. The iron(III) complexes of tripodal ...

  2. Iron (III) complexes of certain tetradentate phenolate ligands as ...

    Indian Academy of Sciences (India)

    Catechol 1,2-dioxygenase (CTD) and protocatechuate 3,4-dioxygenase (PCD) are bacterial non-heme iron enzymes, which catalyse the oxidative cleavage of catechols to cis, cis-muconic acids with the incorporation of molecular oxygen via a mechanism involving a high-spin ferric centre. The iron(III) complexes of tripodal ...

  3. A Direct, Biomass-Based Synthesis of Benzoic Acid: Formic Acid-Mediated Deoxygenation of the Glucose-Derived Materials Quinic Acid and Shikimic Acid

    Energy Technology Data Exchange (ETDEWEB)

    Arceo, Elena; Ellman, Jonathan; Bergman, Robert

    2010-05-03

    An alternative biomass-based route to benzoic acid from the renewable starting materials quinic acid and shikimic acid is described. Benzoic acid is obtained selectively using a highly efficient, one-step formic acid-mediated deoxygenation method.

  4. Synthesis of acid addition salt of delta-aminolevulinic acid from 5-bromo levulinic acid esters

    Science.gov (United States)

    Moens, Luc

    2003-06-24

    A process of preparing an acid addition salt of delta-aminolevulinc acid comprising: a) dissolving a lower alkyl 5-bromolevulinate and hexamethylenetetramine in a solvent selected from the group consisting of water, ethyl acetate, chloroform, acetone, ethanol, tetrahydrofuran and acetonitrile, to form a quaternary ammonium salt of the lower alkyl 5-bromolevulinate; and b) hydrolyzing the quaternary ammonium salt with an inorganic acid to form an acid addition salt of delta-aminolevulinic acid.

  5. Acid Ceramidase in Melanoma

    DEFF Research Database (Denmark)

    Realini, Natalia; Palese, Francesca; Pizzirani, Daniela

    2016-01-01

    Acid ceramidase (AC) is a lysosomal cysteine amidase that controls sphingolipid signaling by lowering the levels of ceramides and concomitantly increasing those of sphingosine and its bioactive metabolite, sphingosine 1-phosphate. In the present study, we evaluated the role of AC-regulated sphing...

  6. Accidents with sulfuric acid

    Directory of Open Access Journals (Sweden)

    Rajković Miloš B.

    2006-01-01

    Full Text Available Sulfuric acid is an important industrial and strategic raw material, the production of which is developing on all continents, in many factories in the world and with an annual production of over 160 million tons. On the other hand, the production, transport and usage are very dangerous and demand measures of precaution because the consequences could be catastrophic, and not only at the local level where the accident would happen. Accidents that have been publicly recorded during the last eighteen years (from 1988 till the beginning of 2006 are analyzed in this paper. It is very alarming data that, according to all the recorded accidents, over 1.6 million tons of sulfuric acid were exuded. Although water transport is the safest (only 16.38% of the total amount of accidents in that way 98.88% of the total amount of sulfuric acid was exuded into the environment. Human factor was the common factor in all the accidents, whether there was enough control of the production process, of reservoirs or transportation tanks or the transport was done by inadequate (old tanks, or the accidents arose from human factor (inadequate speed, lock of caution etc. The fact is that huge energy, sacrifice and courage were involved in the recovery from accidents where rescue teams and fire brigades showed great courage to prevent real environmental catastrophes and very often they lost their lives during the events. So, the phrase that sulfuric acid is a real "environmental bomb" has become clearer.

  7. Salicylic Acid Topical

    Science.gov (United States)

    ... the package label for more information.Apply a small amount of the salicylic acid product to one or two small areas you want to treat for 3 days ... know that children and teenagers who have chicken pox or the flu should not use topical salicylic ...

  8. Multifunctional Cinnamic Acid Derivatives

    Directory of Open Access Journals (Sweden)

    Aikaterini Peperidou

    2017-07-01

    Full Text Available Our research to discover potential new multitarget agents led to the synthesis of 10 novel derivatives of cinnamic acids and propranolol, atenolol, 1-adamantanol, naphth-1-ol, and (benzylamino ethan-1-ol. The synthesized molecules were evaluated as trypsin, lipoxygenase and lipid peroxidation inhibitors and for their cytotoxicity. Compound 2b derived from phenoxyphenyl cinnamic acid and propranolol showed the highest lipoxygenase (LOX inhibition (IC50 = 6 μΜ and antiproteolytic activity (IC50 = 0.425 μΜ. The conjugate 1a of simple cinnamic acid with propranolol showed the higher antiproteolytic activity (IC50 = 0.315 μΜ and good LOX inhibitory activity (IC50 = 66 μΜ. Compounds 3a and 3b, derived from methoxylated caffeic acid present a promising combination of in vitro inhibitory and antioxidative activities. The S isomer of 2b also presented an interesting multitarget biological profile in vitro. Molecular docking studies point to the fact that the theoretical results for LOX-inhibitor binding are identical to those from preliminary in vitro study.

  9. Koetjapic acid chloroform hemisolvate

    Directory of Open Access Journals (Sweden)

    Z. D. Nassar

    2010-06-01

    Full Text Available The asymmetric unit of the title compound, C30H46O4·0.5CHCl3, consists of one koetjapic acid [systematic name: (3R,4aR,4bS,7S,8S,10bS,12aS-7-(2-carboxyethyl-3,4b,7,10b,12a-pentamethyl-8-(prop-1-en-2-yl-1,2,3,4,4a,4b,5,6,7,8,9,10,10b,11,12,12a-hexadecahydrochrysene-3-carboxylic acid] molecule and one half-molecule of chloroform solvent, which is disordered about a twofold rotation axis. The symmetry-independent component is further disordered over two sites, with occupancies of 0.30 and 0.20. The koetjapic acid contains a fused four-ring system, A/B/C/D. The A/B, B/C and C/D junctions adopt E/trans/cis configurations, respectively. The conformation of ring A is intermediate between envelope and half-chair and ring B adopts an envelope conformation whereas rings C and D adopt chair conformations. A weak intramolecular C—H...O hydrogen bond is observed. The koetjapic acid molecules are linked into dimers by two pairs of intermolecular O—H...O hydrogen bonds. The dimers are stacked along the c axis.

  10. Acid dip for dosemeter

    International Nuclear Information System (INIS)

    Stewart, J.C.; McWhan, A.F.

    1982-01-01

    Background signal in a PTFE based dosemeter caused by impurities in the PTFE and in the active component such as lithium fluoride is substantially reduced by treating the dosemeter with acid. The optimum treatment involves use of hydrofluoric acid at room temperature for approximately one minute, followed by thorough washing with methanol, and finally drying. This treatment is best applied after the original manufacture of the dosemeters. It may also be applied to existing dosemeters after they have been in use for some time. The treatment produces a permanent effect in reducing both the light induced signal and the non-light induced signal. The process may be applied to all types of dosemeter manufactured from PTFE or other plastics or resins which are able to resist brief exposure to acid. The treatment works particularly well with dosemeters based on PTFE and lithium fluoride. It is also applicable to dosemeters based on calcium sulphate, lithium borate and magnesium borate. Acids which may be used include hydrofluoric, hydrochloric, nitric, phosphoric and sulphuric. (author)

  11. Hyaluronic Acid Assays

    DEFF Research Database (Denmark)

    Itenov, Theis Skovsgaard; Kirkby, Nikolai S; Bestle, Morten H

    2016-01-01

    BACKGROUD: Hyaluronic acid (HA) is proposed as a marker of functional liver capacity. The aim of the present study was to compare a new turbidimetric assay for measuring HA with the current standard method. METHODS: HA was measured by a particle-enhanced turbidimetric immunoassay (PETIA) and enzyme...

  12. Halogenated fatty acids

    DEFF Research Database (Denmark)

    Mu, Huiling; Sundin, Peter; Wesén, Clas

    1997-01-01

    Halogenated fatty acids are the major contributors to organohalogen compounds in lipids of marine mammals, fish, and bivalves. For the initial characterization of these recently noticed compounds, a determination of the halogen concentration has usually been combined with some lipid isolation and...

  13. and amino acids

    Indian Academy of Sciences (India)

    Unknown

    (L-Trp), were obtained from Sigma Chemical Company (USA). All the metal ions Cu(II),. Ni(II) and .... respective free amino acids show characteristic band positions, shifts and intensities, which can be correlated to ..... Financial support from the University Grants Commission, New Delhi to Prof P Rabindra. Reddy is gratefully ...

  14. [Acid hydrolysis of mandioca].

    Science.gov (United States)

    Colombo, A J; Schneiderman, B; Baruffaldi, R; Nacco, R

    1975-01-01

    The influence of time of hydrolysis, pression of the process, ratio of mass of flour and volume and concentration of the acid solution was studied in the hydrolytic processes for Cassava flour. The aim was to obtain fermentable sugars, and the results were submitted to variance analysis.

  15. Hurnic acid protein complexation

    NARCIS (Netherlands)

    Tan, W. F.; Koopal, L. K.; Weng, L. P.; van Riemsdijk, W. H.; Norde, W.

    2008-01-01

    Interactions of purified Aldrich humic acid (PAHA) with lysozyme (LSZ) are investigated. In solution LSZ is moderately positively and PAHA negatively charged at the investigated pH values. The proton binding of PAHA and of LSZ is determined by potentiometric proton titrations at various KCl

  16. Nanoclusters of Cyanuric Acid

    Indian Academy of Sciences (India)

    Hydrogen bonding; molecular clusters; cyanuric acid; self-assembly; symmetry. ... Chemical Laboratory, CSIR-Central Leather Research Institute, Adyar, Chennai 600 020, India; Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, USA; Indian Institute of Science Education and ...

  17. Kainic acid and 1'-hydroxykainic acid from Palmariales.

    Science.gov (United States)

    Ramsey, U P; Bird, C J; Shacklock, P F; Laycock, M V; Wright, J L

    1994-01-01

    The distribution of kainic acid among various red algae was investigated. Analysis of free amino acids from different populations of Palmaria palmata showed that some were unable to accumulate kainic acid to detectable concentrations, whereas in two dwarf mutants it was a major component of the free amino acid composition. The amino acid profiles were also examined for unknown amino acids in the search for possible intermediates in kainic acid biosynthesis. The only unknown amino acid present in P. palmata extracts was isolated and identified by NMR spectroscopy as 1'-hydroxykainic acid. This compound was found in all samples that contained kainic acid. To investigate the effect of growth conditions on kainic acid production different strains of P. palmata were grown at 5, 10, and 15 degrees C with or without added nitrate. No effect on production was observed, suggesting that the growth conditions in these experiments do not affect the level of gene expression in the pathway of kainic acid biosynthesis. Furthermore, changing the growth conditions did not induce synthesis of kainic acid in the non-producing strains of Palmariales.

  18. Vaccinium virgatum fruit extract as an important adjuvant in biochemical and behavioral alterations observed in animal model of metabolic syndrome.

    Science.gov (United States)

    Oliveira, Pathise Souto; Gazal, Marta; Flores, Natália Porto; Zimmer, Aline Rigon; Chaves, Vitor Clasen; Reginatto, Flávio Henrique; Kaster, Manuella Pinto; Tavares, Rejane Giacomelli; Spanevello, Roselia Maria; Lencina, Claiton Leoneti; Stefanello, Francieli Moro

    2017-04-01

    The aim of this study was to investigate the effect of blueberry (Vaccinium virgatum) fruit extract on metabolic, behavioral and oxidative stress parameters in the hippocampus and cerebral cortex of mice submitted to an experimental model of metabolic syndrome induced by a highly palatable diet (HPD). Mice C57BL/6 were divided into 4 experimental groups: (1) received standard chow and saline orally, (2) received standard chow and blueberry hydroalcoholic extract, (3) received HPD and saline orally, (4) received HPD and blueberry hydroalcoholic extract. The animals were treated for 150days. Our results showed that the animals fed with HPD presented insulin resistance, increased body weight, visceral fat, glucose, triglycerides, and total cholesterol when compared to the control group. The blueberry extract prevented the increase of these metabolic parameters. Also, the extract was able to reduce the levels of thiobarbituric acid reactive substances in the cerebral cortex and hippocampus of animals submitted to HPD. In contrast, no differences were observed in the total thiol content, activity of the antioxidant enzymes catalase and superoxide dismutase. In addition, the HPD fed animals showed a significant increase in immobility time in the forced swimming test and blueberry prevented this alteration, although no changes were observed in the ambulatory behavior, as well as in the anxiolytic profile of these animals. Overall, our findings suggest that chronic consumption of blueberry extract exhibits hypoglycemic, hypolipidemic, antidepressant-like and antiperoxidative effects in an animal model of metabolic syndrome. Copyright © 2017. Published by Elsevier Masson SAS.

  19. Dentate gyrus and hilus transection blocks seizure propagation and granule cell dispersion in a mouse model for mesial temporal lobe epilepsy.

    Science.gov (United States)

    Pallud, Johan; Häussler, Ute; Langlois, Mélanie; Hamelin, Sophie; Devaux, Bertrand; Deransart, Colin; Depaulis, Antoine

    2011-03-01

    Epilepsy-associated changes of the anatomical organization of the dentate gyrus and hilus may play a critical role in the initiation and propagation of seizures in mesial temporal lobe epilepsy (MTLE). This study evaluated the role of longitudinal projections in the propagation of hippocampal paroxysmal discharges (HPD) in dorsal hippocampus by performing a selective transection in a mouse model for MTLE obtained by a single unilateral intrahippocampal injection of kainic acid (KA). Full transections of the dentate gyrus and hilus were performed in the transverse axis at 22 days after KA injection when spontaneous HPD were fully developed. They: (i) significantly reduced the occurrence of HPD; (ii) increased their duration at the KA injection site; (iii) abolished their spread along the longitudinal axis of the hippocampal formation and; (iv) limited granule cell dispersion (GCD) of the dentate gyrus posterior to the transection. These data suggest that: (i) longitudinal projections through the dentate gyrus and hilus are involved in HPD spread; (ii) distant hippocampal circuits participate in the generation and cessation of HPD and; (iii) GCD requires continuous HPD to develop, even when seizures are established. Our data reveal a critical role for longitudinal projections in the generation and spread of hippocampal seizures. Copyright © 2010 Wiley-Liss, Inc.

  20. Fatty acid-producing hosts

    Science.gov (United States)

    Pfleger, Brian F; Lennen, Rebecca M

    2013-12-31

    Described are hosts for overproducing a fatty acid product such as a fatty acid. The hosts include an exogenous nucleic acid encoding a thioesterase and, optionally, an exogenous nucleic acid encoding an acetyl-CoA carboxylase, wherein an acyl-CoA synthetase in the hosts are functionally delected. The hosts prefereably include the nucleic acid encoding the thioesterase at an intermediate copy number. The hosts are preferably recominantly stable and growth-competent at 37.degree. C. Methods of producing a fatty acid product comprising culturing such hosts at 37.degree. C. are also described.

  1. Progress in engineering acid stress resistance of lactic acid bacteria.

    Science.gov (United States)

    Wu, Chongde; Huang, Jun; Zhou, Rongqing

    2014-02-01

    Lactic acid bacteria (LAB) are widely used for the production of a variety of fermented foods, and are considered as probiotic due to their health-promoting effect. However, LAB encounter various environmental stresses both in industrial fermentation and application, among which acid stress is one of the most important survival challenges. Improving the acid stress resistance may contribute to the application and function of probiotic action to the host. Recently, the advent of genomics, functional genomics and high-throughput technologies have allowed for the understanding of acid tolerance mechanisms at a systems level, and many method to improve acid tolerance have been developed. This review describes the current progress in engineering acid stress resistance of LAB. Special emphasis is placed on engineering cellular microenvironment (engineering amino acid metabolism, introduction of exogenous biosynthetic capacity, and overproduction of stress response proteins) and maintaining cell membrane functionality. Moreover, strategies to improve acid tolerance and the related physiological mechanisms are also discussed.

  2. Adipic acid tolerance screening for potential adipic acid production hosts.

    Science.gov (United States)

    Karlsson, Emma; Mapelli, Valeria; Olsson, Lisbeth

    2017-02-01

    Biobased processes for the production of adipic acid are of great interest to replace the current environmentally detrimental petrochemical production route. No efficient natural producer of adipic acid has yet been identified, but several approaches for pathway engineering have been established. Research has demonstrated that the microbial production of adipic acid is possible, but the yields and titres achieved so far are inadequate for commercialisation. A plausible explanation may be intolerance to adipic acid. Therefore, in this study, selected microorganisms, including yeasts, filamentous fungi and bacteria, typically used in microbial cell factories were considered to evaluate their tolerance to adipic acid. Screening of yeasts and bacteria for tolerance to adipic acid was performed in microtitre plates, and in agar plates for A. niger in the presence of adipic acid over a broad range of concentration (0-684 mM). As the different dissociation state(s) of adipic acid may influence cells differently, cultivations were performed with at least two pH values. Yeasts and A. niger were found to tolerate substantially higher concentrations of adipic acid than bacteria, and were less affected by the undissociated form of adipic acid than bacteria. The yeast exhibiting the highest tolerance to adipic acid was Candida viswanathii, showing a reduction in maximum specific growth rate of no more than 10-15% at the highest concentration of adipic acid tested and the tolerance was not dependent on the dissociation state of the adipic acid. Tolerance to adipic acid was found to be substantially higher among yeasts and A. niger than bacteria. The explanation of the differences in adipic acid tolerance between the microorganisms investigated are likely related to fundamental differences in their physiology and metabolism. Among the yeasts investigated, C. viswanathii showed the highest tolerance and could be a potential host for a future microbial cell factory for adipic acid.

  3. Boswellic acid inhibits expression of acid sphingomyelinase in intestinal cells

    Directory of Open Access Journals (Sweden)

    Duan Rui-Dong

    2009-12-01

    Full Text Available Abstract Background Boswellic acid is a type of triterpenoids with antiinflammatory and antiproliferative properties. Sphingomyelin metabolism generates multiple lipid signals affecting cell proliferation, inflammation, and apoptosis. Upregulation of acid sphingomyelinase (SMase has been found in several inflammation-related diseases such as inflammatory bowel diseases, atherosclerosis, and diabetes. Methods The present study is to examine the effect of 3-acetyl-11-keto-β-boswellic acids (AKBA, a potent boswellic acid, on acid SMase activity and expression in intestinal cells. Both transformed Caco-2 cells and non-transformed Int407 cells were incubated with AKBA. After incubation, the change of acid SMase activity was assayed biochemically, the enzyme protein was examined by Western blot, and acid SMase mRNA was quantified by qPCR. Results We found that AKBA decreased acid SMase activity in both intestinal cell lines in dose and time dependent manners without affecting the secretion of the enzyme to the cell culture medium. The effect of AKBA was more effective in the fetal bovine serum-free culture medium. Among different types of boswellic acid, AKBA was the most potent one. The inhibitory effect on acid SMase activity occurred only in the intact cells but not in cell-free extract in the test tubes. At low concentration, AKBA only decreased the acid SMase activity but not the quantity of the enzyme protein. However, at high concentration, AKBA decreased both the mass of acid SMase protein and the mRNA levels of acid SMase in the cells, as demonstrated by Western blot and qPCR, respectively. Under the concentrations decreasing acid SMase activity, AKBA significantly inhibited cell proliferation. Conclusion We identified a novel inhibitory effect of boswellic acids on acid SMase expression, which may have implications in human diseases and health.

  4. Selective hydrodeoxygenation of tartaric acid to succinic acid

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Jiayi [Department of Chemical and Biomolecular Engineering; University of Delaware; Newark; USA; Catalysis Center for Energy Innovation; Vasiliadou, Efterpi S. [Catalysis Center for Energy Innovation; University of Delaware; Newark; USA; Goulas, Konstantinos A. [Catalysis Center for Energy Innovation; University of Delaware; Newark; USA; Saha, Basudeb [Catalysis Center for Energy Innovation; University of Delaware; Newark; USA; Vlachos, Dionisios G. [Department of Chemical and Biomolecular Engineering; University of Delaware; Newark; USA; Catalysis Center for Energy Innovation

    2017-01-01

    A novel one-step process for the selective production of succinic acid from tartaric acid is developed. High succinic yield is achieved in an efficient catalytic system comprised of MoOx/BC, HBr and acetic acid under hydrogen atmosphere.

  5. Formic acid assisted hydrogenation of levulinic acid to ...

    Indian Academy of Sciences (India)

    Muppala Ashokraju

    2018-02-07

    Feb 7, 2018 ... formic acid) as it is obtained through the hydrolysis of biomass that contains water. In this context, we have per- formed the hydrogenation of levulinic acid with formic acid in presence of water (LA: FA: H2O 1:5:1) and the results are displayed in Figure 7b. The results indicate better performance of the cat-.

  6. Acetic acid extraction from aqueous solutions using fatty acids

    NARCIS (Netherlands)

    IJmker, H.M.; Gramblicka, M.; Kersten, Sascha R.A.; van der Ham, Aloysius G.J.; Schuur, Boelo

    2014-01-01

    A major challenge for production of acetic acid via bio-based routes is cost-effective concentration and purification of the acetic acid from the aqueous solutions, for which liquid–liquid extraction is a possible method. A main challenge in extraction of acetic acid from dilute aqueous solutions is

  7. Cytotoxic effect of betulinic acid and betulinic acid acetate isolated ...

    African Journals Online (AJOL)

    Cytotoxic effect of betulinic acid and betulinic acid acetate isolated from Melaleuca cajuput on human myeloid leukemia (HL-60) cell line. ... The cytotoxic effect of betulinic acid (BA), isolated from Melaleuca cajuput a Malaysian plant and its four synthetic derivatives were tested for their cytotoxicity in various cell line or ...

  8. (Radioiodinated free fatty acids)

    Energy Technology Data Exchange (ETDEWEB)

    Knapp, Jr., F. F.

    1987-12-11

    The traveler participated in the Second International Workshop on Radioiodinated Free Fatty Acids in Amsterdam, The Netherlands where he presented an invited paper describing the pioneering work at the Oak Ridge National Laboratory (ORNL) involving the design, development and testing of new radioiodinated methyl-branched fatty acids for evaluation of heart disease. He also chaired a technical session on the testing of new agents in various in vitro and in vivo systems. He also visited the Institute for Clinical and Experimental Nuclear Medicine in Bonn, West Germany, to review, discuss, plan and coordinate collaborative investigations with that institution. In addition, he visited the Cyclotron Research Center in Liege, Belgium, to discuss continuing collaborative studies with the Osmium-191/Iridium-191m radionuclide generator system, and to complete manuscripts and plan future studies.

  9. Acid hydrolysis of cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Salazar, H.

    1980-12-01

    One of the alternatives to increase world production of etha nol is by the hydrolysis of cellulose content of agricultural residues. Studies have been made on the types of hydrolysis: enzimatic and acid. Data obtained from the sulphuric acid hydrolysis of cellulose showed that this process proceed in two steps, with a yield of approximately 95% glucose. Because of increases in cost of alternatives resources, the high demand of the product and the more economic production of ethanol from cellulose materials, it is certain that this technology will be implemented in the future. At the same time further studies on the disposal and reuse of the by-products of this production must be undertaken.

  10. Bile acids for viral hepatitis

    DEFF Research Database (Denmark)

    Chen, Weikeng; Liu, J; Gluud, C

    2007-01-01

    Trials have assessed bile acids for patients with viral hepatitis, but no consensus has been reached regarding their usefulness.......Trials have assessed bile acids for patients with viral hepatitis, but no consensus has been reached regarding their usefulness....

  11. Omega-3 fatty acids (image)

    Science.gov (United States)

    Omega-3 fatty acids are a form of polyunsaturated fat that the body derives from food. Omega-3s (and omega-6s) are known as essential fatty acids (EFAs) because they are important for good health. ...

  12. Electrochemistry of nucleic acids

    Czech Academy of Sciences Publication Activity Database

    Paleček, Emil; Bartošík, Martin

    2012-01-01

    Roč. 112, č. 6 (2012), s. 3427-3481 ISSN 0009-2665 R&D Projects: GA ČR(CZ) GAP301/11/2055; GA MŠk(CZ) ME09038; GA MŠk(CZ) LC06035 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : nucleic acids electrochemistry * DNA biosensors * DNA damage Subject RIV: BO - Biophysics Impact factor: 41.298, year: 2012

  13. Whence the acid raindrop

    International Nuclear Information System (INIS)

    Heaton, T.H.E.

    1987-01-01

    Absorption of NO 2 can cause damage in animals and plants and, if present trends for NO x emissions continue, their by-product nitric acid may soon overtake sulphuric acid as the main acidifying agent of 'acid' rain. In response to this problem the feasibility of reducing NO x emissions from power stations is being studied. Although there can be no doubt that these expensive controls are desirable, their benefits are difficult to predict for two reasons: NO x is not only emitted by fuel combustion and the degree to which an industrialised country benefits from the implementation of NO x emission controls depends on how much its pollutant 'fall out' is immediately returned from the atmosphere, and how much is exported to neighbouring countries. The above factors involve questions regarding the source and reaction mechanisms for nitrogen compounds in the atmosphere. Because stable isotope ratio analysis has proved to be of value in providing answers to such questions in other environments, an investigation of the 15 N/ 14 N ratios of atmospheric gases (NO x , NH 3 ) and their solution products in rain (NO 3 , NH + 4 ) seemed to be justified

  14. LACTIC ACID BACTERIA: PROBIOTIC APPLICATIONS

    OpenAIRE

    NEENA GARG

    2015-01-01

    Lactic acid bacteria (LAB) is a heterotrophic Gram-positive bacteria which under goes lactic acid fermentations and leads to production of lactic acid as an end product. LAB includes Lactobacillus, Leuconostoc, Pediococcus, Lactococcus and Streptococcus which are grouped together in the family lactobacillaceae. LAB shows numerous antimicrobial activities due to production of antibacterial and antifungal compounds such as organic acids, bacteriocins, diacetyl, hydrogen peroxide and reutrin. LA...

  15. Levulinic acid in organic synthesis

    International Nuclear Information System (INIS)

    Timokhin, Boris V; Baransky, V A; Eliseeva, G D

    1999-01-01

    Data concerning the methods of synthesis, chemical transformations and application of levulinic acid are analysed and generalised. The wide synthetic potential of levulinic acid, particularly as a key compound in the synthesis of various heterocyclic systems, saturated and unsaturated ketones and diketones, difficultly accessible acids and other compounds is demonstrated. The accessibility of levulinic acid from hexose-containing wood-processing and agricultural wastes is noted. The bibliography includes 260 references.

  16. Acids and bases solvent effects on acid-base strenght

    CERN Document Server

    Cox, Brian G

    2013-01-01

    Acids and bases are ubiquitous in chemistry. Our understanding of them, however, is dominated by their behaviour in water. Transfer to non-aqueous solvents leads to profound changes in acid-base strengths and to the rates and equilibria of many processes: for example, synthetic reactions involving acids, bases and nucleophiles; isolation of pharmaceutical actives through salt formation; formation of zwitter- ions in amino acids; and chromatographic separation of substrates. This book seeks to enhance our understanding of acids and bases by reviewing and analysing their behaviour in non-aqueous solvents. The behaviour is related where possible to that in water, but correlations and contrasts between solvents are also presented.

  17. Macrocyclic polyether complexes of amino acids and amino acid salts

    International Nuclear Information System (INIS)

    Bidzilya, V.A.; Oleksenko, LP.

    1985-01-01

    This paper deals with the isolation of the complexes formed between various types of amino acid derivatives and macrocyclic polyethers, and the characterisation of their physical and chemical properties. The study shows that macrocyclic polyethers form 1:1 complexes with amino acids and amino acid derivatives, and that these complexes can be isolated in pure form. Amino acids can be bound to these complexes in their anionic forms, in switterionic forms, as well as in their protonated forms. These types of complexes may be useful for the transport of amino acids or their derivatives across both synthetic and natural membranes

  18. Age-related mechanism and its relationship with secondary metabolism and abscisic acid in Aristotelia chilensis plants subjected to drought stress.

    Science.gov (United States)

    González-Villagra, Jorge; Rodrigues-Salvador, Acácio; Nunes-Nesi, Adriano; Cohen, Jerry D; Reyes-Díaz, Marjorie M

    2018-03-01

    Drought stress is the most important stress factor for plants, being the main cause of agricultural crop loss in the world. Plants have developed complex mechanisms for preventing water loss and oxidative stress such as synthesis of abscisic acid (ABA) and non-enzymatic antioxidant compounds such as anthocyanins, which might help plants to cope with abiotic stress as antioxidants and for scavenging reactive oxygen species. A. chilensis (Mol.) is a pioneer species, colonizing and growing on stressed and disturbed environments. In this research, an integrated analysis of secondary metabolism in Aristotelia chilensis was done to relate ABA effects on anthocyanins biosynthesis, by comparing between young and fully-expanded leaves under drought stress. Plants were subjected to drought stress for 20 days, and physiological, biochemical, and molecular analyses were performed. The relative growth rate and plant water status were reduced in stressed plants, with young leaves significantly more affected than fully-expanded leaves beginning from the 5th day of drought stress. A. chilensis plants increased their ABA and total anthocyanin content and showed upregulation of gene expression when they were subjected to severe drought (day 20), with these effects being higher in fully-expanded leaves. Multivariate analysis indicated a significant positive correlation between transcript levels for NCED1 (9-cis-epoxycarotenoid dioxygenase) and UFGT (UDP glucose: flavonoid-3-O-glucosyltransferase) with ABA and total anthocyanin, respectively. Thus, this research provides a more comprehensive analysis of the mechanisms that allow plants to cope with drought stress. This is highlighted by the differences between young and fully-expanded leaves, showing different sensibility to stress due to their ability to synthesize anthocyanins. In addition, this ability to synthesize different and high amounts of anthocyanins could be related to higher NCED1 and MYB expression and ABA levels

  19. Sustained increases in cerebrospinal fluid quinolinic acid concentrations in rhesus macaques (Macaca mulatta) naturally infected with simian retrovirus type-D.

    Science.gov (United States)

    Heyes, M P; Gravell, M; London, W T; Eckhaus, M; Vickers, J H; Yergey, J A; April, M; Blackmore, D; Markey, S P

    1990-10-29

    Sustained increases in CSF concentrations of the excitotoxin quinolinic acid (QUIN) occur in patients with AIDS and have been implicated in the pathogenesis of the AIDS dementia complex. Macaques in captivity may also develop immunodeficiency syndromes caused by retrovirus infection, including simian retrovirus type-D. In the present study, CSF QUIN concentrations were moderately increased in retrovirus type-D-positive/antibody-negative macaques (163.8 +/- 35.1 nmol/l; P less than 0.0001, n = 21) but not virus-negative/antibody-positive macaques (27.4 +/- 9.4 nmol/l, n = 8) compared to uninfected control macaques (23.0 +/- 1.6 nmol/l; n = 22). CSF QUIN concentrations in virus-positive/antibody-negative macaques tended to remain elevated over a 4-20 month period. Post-mortem studies of 9 virus-positive/antibody-negative macaques and 6 virus-negative/antibody-positive macaques revealed inflammatory responses in the brains of 6 of 9 virus-positive/antibody negative macaques, including lymphocytic infiltrates of the choroid plexus in 3 macaques, glial nodules in 3 macaques and perivascular infiltrates in 1 macaque. These lesions were not extensive and no evidence of brain atrophy was observed. No lesions were observed in the 6 antibody-positive/virus-negative macaques. Small increases in plasma L-kynurenine in virus-positive/antibody-negative macaques are consistent with activation of indoleamine-2,3-dioxygenase, the first enzyme in the kynurenine pathway. We conclude that sustained moderate increases in CSF QUIN occur in viremic simian retrovirus type-D macaques. The increases in CSF QUIN may reflect inflammatory responses within the brain or synthesis of QUIN precursors in systemic tissues, their entry into brain and subsequent conversion to QUIN. The neuropathologic significance of these increases in CSF QUIN remains to be determined.

  20. Sequential injection redox or acid-base titration for determination of ascorbic acid or acetic acid.

    Science.gov (United States)

    Lenghor, Narong; Jakmunee, Jaroon; Vilen, Michael; Sara, Rolf; Christian, Gary D; Grudpan, Kate

    2002-12-06

    Two sequential injection titration systems with spectrophotometric detection have been developed. The first system for determination of ascorbic acid was based on redox reaction between ascorbic acid and permanganate in an acidic medium and lead to a decrease in color intensity of permanganate, monitored at 525 nm. A linear dependence of peak area obtained with ascorbic acid concentration up to 1200 mg l(-1) was achieved. The relative standard deviation for 11 replicate determinations of 400 mg l(-1) ascorbic acid was 2.9%. The second system, for acetic acid determination, was based on acid-base titration of acetic acid with sodium hydroxide using phenolphthalein as an indicator. The decrease in color intensity of the indicator was proportional to the acid content. A linear calibration graph in the range of 2-8% w v(-1) of acetic acid with a relative standard deviation of 4.8% (5.0% w v(-1) acetic acid, n=11) was obtained. Sample throughputs of 60 h(-1) were achieved for both systems. The systems were successfully applied for the assays of ascorbic acid in vitamin C tablets and acetic acid content in vinegars, respectively.

  1. Excitatory amino acid receptor antagonists

    DEFF Research Database (Denmark)

    Johansen, T N; Frydenvang, Karla Andrea; Ebert, B

    1997-01-01

    We have previously shown that (RS)-2-amino-2-(5-tert-butyl-3-hydroxyisoxazol-4-yl)acetic acid (ATAA) is an antagonist at N-methyl-D-aspartic acid (NMDA) and (RS)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) receptors. We have now resolved ATAA via diastereomeric salt formation...

  2. Pantothenic acid biosynthesis in zymomonas

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Luan; Tomb, Jean-Francois; Viitanen, Paul V.

    2014-07-01

    Zymomonas is unable to synthesize pantothenic acid and requires this essential vitamin in growth medium. Zymomonas strains transformed with an operon for expression of 2-dehydropantoate reductase and aspartate 1-decarboxylase were able to grow in medium lacking pantothenic acid. These strains may be used for ethanol production without pantothenic acid supplementation in seed culture and fermentation media.

  3. Fumaric acid production by fermentation

    NARCIS (Netherlands)

    Roa Engel, C.A.; Straathof, A.J.J.; Zijlmans, T.W.; Van Gulik, W.M.; Van der Wielen, L.A.M.

    2008-01-01

    Abstract The potential of fumaric acid as a raw material in the polymer industry and the increment of cost of petroleum-based fumaric acid raises interest in fermentation processes for production of this compound from renewable resources. Although the chemical process yields 112% w/w fumaric acid

  4. Waste acid detoxification and reclamation

    International Nuclear Information System (INIS)

    Brouns, T.M.; Stewart, T.L.

    1988-01-01

    Economically feasible processes that reduce the volume, quantity, and toxicity of metal-bearing waste acids by reclaiming, reusing, and recycling spent acids and metal salts are being developed and demonstrated. The acids used in the demonstrations are generated during metal-finishing operations used in nuclear fuel fabrication; HF-HNO 3 , HNO 3 , and HNO 3 -H 2 SO 4 wastes result from Zr etching, Cu stripping, and chemical milling of U. At discharge, wastes contain high concentrations of acid and one major metal impurity. The waste minimization process used to reclaim acid from these three streams incorporates three processes for acid regeneration and reclamation. Normally, HNO 3 remains in the bottoms when an aqueous acid solution is distilled; however, in the presence of H 2 SO 4 , HNO 3 will distill to the overhead stream. In this process, nitrates and fluorides present as free acid and metal salts can be reclaimed as acid for recycle to the metal-finishing processes. Uranium present in the chemical milling solution can be economically recovered from distillation bottoms and refined. Using acid distillation, the volume of chemical milling solution discharged as waste can be reduced by as much as 60% depending on the H 2 SO 4 concentration. A payback period of 2.2 years has been estimated for this process. The development and demonstration of precipitation and distillation processes for detoxification and reclamation of waste acid is supported by the US Department of Energy's Hazardous Waste Remedial Actions Program (HAZWRAP)

  5. Acidic aerosol in urban air

    Energy Technology Data Exchange (ETDEWEB)

    Fukuda, M.; Yamaoka, S.; Miyazaki, T.; Oka, M.

    1982-01-01

    The distribution and chemical composition of acidic aerosol in Osaka City were investigated. Samples were collected at five sites in the city from June to September, 1979. Acidic aerosol was determined by the acid-base titration method, sulfate ion by barium chloride turbidimetry, nitrate ion by the xylenol method, and chloride ion by the mercury thiocyanate method. The concentration of acidic aerosol at five sites ranged from 7.7 micrograms per cubic meter to 10.0 micrograms per cubic meter, but mean concentrations in the residential area were slightly higher than those in the industrial area. When acidic aerosol concentrations were compared with concentrations of sulfate, nitrate, and chloride ions, a significant correlation was found between acidic aerosol and sulfate ion. The sum of the ion equivalents of the three types showed good correlation with the acidic aerosol equivalent during the whole period.

  6. Adsorption of humic acid on acid-activated Greek bentonite.

    Science.gov (United States)

    Doulia, Danae; Leodopoulos, Ch; Gimouhopoulos, K; Rigas, F

    2009-12-15

    The adsorption of humic acid on bentonite from Milos Island (Greece) acid-treated with dilute H(2)SO(4) solutions over a concentration range between 0.25 and 13M has been studied. Bentonite activated with 3M sulfuric acid (AAS) showed a higher efficiency in removing humic acid from aqueous solutions and was selected for further investigation. The specific surface area of acid-activated bentonite was estimated using the methylene blue adsorption method. The morphology of untreated, activated, and HA-sorbed bentonite was studied under scanning electron microscope (SEM). The effects of contact time, adsorbate concentration, adsorbent dose, and temperature on the adsorption of humic acid onto bentonite activated with 3M H(2)SO(4) were studied using a batch adsorption technique. Acidic pH and high ionic strength proved to be favorable for the adsorption efficiency. Pseudo-first-order, pseudo-second-order, and intraparticle diffusion models were used to describe the kinetic data and the rate constants were evaluated. The experimental isotherm data were analyzed using Langmuir, Freundlich, and Temkin equations and the isotherm constants were determined. Thermodynamic parameters (DeltaH(o), DeltaS(o), and DeltaG(o)) of adsorption of humic acid onto acid-activated bentonite with 3M sulfuric acid were also evaluated.

  7. Cytenamide acetic acid solvate

    OpenAIRE

    Johnston, Andrea; Florence, Alastair J.; Fabianni, Francesca J. A.; Shankland, Kenneth; Bedford, Colin T.

    2008-01-01

    In the crystal structure of the title compound (systematic name: 5H-dibenzo[a,d]cycloheptatriene-5-carboxamide ethanoic acid solvate), C16H13NO C2H4O2, the cytenamide and solvent molecules form a hydrogen-bonded R2 2(8) dimer motif, which is further connected to form a centrosymmetric double ring motif arrangement. The cycloheptene ring adopts a boat conformation and the dihedral angle between the leastsquares planes through the two aromatic rings is 54.7 (2) . peer...

  8. Crassulacean acid metabolism

    Directory of Open Access Journals (Sweden)

    Thomas David Geydan

    2005-07-01

    Full Text Available A review of Crassulacean acid metabolism is presented, characterized by showing the occurrence, activity and plasticity of these complex mechanism at the physiological, biochemical and molecular level, framed by the presence of the denominated four phases in CAM and its repercussion and expression due to different stresses in an ecological context. The basic enzymes, and metabolites necessary for the optional functioning of CAM are presented as well as their mode of action and cellular control. Finally, it is shown how environmental conditions and molecular signalling mediate the phenotypic plasticity.

  9. New Acid Combination for a Successful Sandstone Acidizing

    Science.gov (United States)

    Shafiq, M. U.; Mahmud, H. K. B.; Rezaee, R.

    2017-05-01

    With the development of new enhanced oil recovery techniques, sandstone acidizing has been introduced and played a pivotal role in the petroleum industry. Different acid combinations have been applied, which react with the formation, dissolve the soluble particles; thus increase the production of hydrocarbons. To solve the problems which occurred using current preflush sandstone acidizing technology (hydrochloric acid); a new acid combination has been developed. Core flooding experiments on sandstone core samples with dimensions 1.5 in. × 3 in. were conducted at a flow rate of 2 cm3/min. A series of hydrochloric-acetic acid mixtures with different ratios were tested under 150°F temperature. The core flooding experiments performed are aimed to dissolve carbonate, sodium, potassium and calcium particles from the core samples. These experiments are followed by few important tests which include, porosity-permeability, pH value, Inductively Coupled Plasma (ICP) analysis and Nuclear Magnetic Resonance (NMR measurements). All the results are compared with the results of conventional hydrochloric acid technology. NMR and porosity analysis concluded that the new acid combination is more effective in creating fresh pore spaces and thus increasing the reservoir permeability. It can be seen from the pore distribution before and after the acidizing. Prior applying acid; the large size of pores appears most frequently in the pore distribution while with the applied acid, it was found that the small pore size is most the predominant of the pore distribution. These results are validated using ICP analysis which shows the effective removal of calcium and other positive ions from the core sample. This study concludes that the combination of acetic-hydrochloric acid can be a potential candidate for the preflush stage of sandstone acidizing at high temperature reservoirs.

  10. Simultaneous liquid-chromatographic quantitation of salicylic acid, salicyluric acid, and gentisic acid in urine.

    Science.gov (United States)

    Cham, B E; Bochner, F; Imhoff, D M; Johns, D; Rowland, M

    1980-01-01

    We have developed a specific and sensitive method for the determination of salicylic acid, salicyluric acid, and gentisic acid in urine. Any proteins present are precipitated with methyl cyanide. After centrifugation, an aliquot of the supernate is directly injected into an octadecyl silane reversed-phase chromatographic column, then eluted with a mixture of water, butanol, acetic acid, and sodium sulfate, and quantitated at 313 nm by ultraviolet detection according to peak-height ratios (with internal standard, o-methoxybenzoic acid) or peak heights (no internal standard). The method allows estimates within 25 min. Sensitivity was 0.2 mg/L for gentisic acid, and 0.5 mg/L for both salicyluric and salicylic acid (20-micro L injection volume); response was linear with concentration to at least 2.000 g/L for salicylic acid and metabolites. Analytical recovery of salicylic acid and metabolites from urine is complete. Intra-assay precision (coefficient of variation) is 5.52% at 7.5 mg/L for salicylic acid, 5.01% at 9.33 mg/L for salicyluric acid, and 3.07% at 7.96 mg/L for gentisic acid. Interassay precision is 7.32% at 7.51 mg/L for salicylic acid, 5.52% at 8.58 mg/L for salicyluric acid, and 3.97% at 8.32 mg/L for gentisic acid. We saw no significant interference in urine from patients being treated with various drugs other than aspirin.

  11. Vibrational structure of the polyunsaturated fatty acids eicosapentaenoic acid and arachidonic acid studied by infrared spectroscopy

    Science.gov (United States)

    Kiefer, Johannes; Noack, Kristina; Bartelmess, Juergen; Walter, Christian; Dörnenburg, Heike; Leipertz, Alfred

    2010-02-01

    The spectroscopic discrimination of the two structurally similar polyunsaturated C 20 fatty acids (PUFAs) 5,8,11,14,17-eicosapentaenoic acid and 5,8,11,14-eicosatetraenoic acid (arachidonic acid) is shown. For this purpose their vibrational structures are studied by means of attenuated total reflection (ATR) Fourier-transform infrared (FT-IR) spectroscopy. The fingerprint regions of the recorded spectra are found to be almost identical, while the C-H stretching mode regions around 3000 cm -1 show such significant differences as results of electronic and molecular structure alterations based on the different degree of saturation that both fatty acids can be clearly distinguished from each other.

  12. 2-arylureidobenzoic acids

    DEFF Research Database (Denmark)

    Valgeirsson, Jon; Nielsen, Elsebet Ø; Peters, Dan

    2003-01-01

    A series of 2-arylureidobenzoic acids (AUBAs) was prepared by a short and effective synthesis, and the pharmacological activity at glutamate receptors was evaluated in vitro and in vivo. The compounds showed noncompetitive antagonistic activity at the kainate receptor subtype GluR5. The most potent...... on the benzoic acid moiety (ring A), whereas ring B tolerated a variety of substituents, but with a preference for lipophilic substituents. The most potent compounds had a 4-chloro substituent on ring A and 3-chlorobenzene (6b), 2-naphthalene (8h), or 2-indole (8k) as ring B and had IC(50) values of 1.3, 1.......2, and 1.2 microM, respectively, in a functional GluR5 assay. Compound 6c (IC(50) = 4.8 microM at GluR5) showed activity in the in vivo ATPA rigidity test, indicating that 6c has better pharmacokinetic properties than 8h, which was inactive in this test. The AUBAs are the first example of a series...

  13. Solid acid catalysis from fundamentals to applications

    CERN Document Server

    Hattori, Hideshi

    2014-01-01

    IntroductionTypes of solid acid catalystsAdvantages of solid acid catalysts Historical overviews of solid acid catalystsFuture outlookSolid Acids CatalysisDefinition of acid and base -Brnsted acid and Lewis acid-Acid sites on surfacesAcid strengthRole of acid sites in catalysisBifunctional catalysisPore size effect on catalysis -shape selectivity-Characterization of Solid Acid Catalysts Indicator methodTemperature programmed desorption (TPD) of ammoniaCalorimetry of adsorption of basic moleculesInfrare

  14. Maleic acid and succinic acid in fermented alcoholic beverages are the stimulants of gastric acid secretion.

    Science.gov (United States)

    Teyssen, S; González-Calero, G; Schimiczek, M; Singer, M V

    1999-03-01

    Alcoholic beverages produced by fermentation (e.g., beer and wine) are powerful stimulants of gastric acid output and gastrin release in humans. The aim of this study was to separate and specify the gastric acid stimulatory ingredients in alcoholic beverages produced by fermentation. Yeast-fermented glucose was used as a simple model of fermented alcoholic beverages; it was stepwise separated by different methods of liquid chromatography, and each separated solution was tested in human volunteers for its stimulatory action on gastric acid output and gastrin release. Five substances were detected by high-performance liquid chromatography and were analyzed by mass spectrometry and 1H-13C nuclear magnetic resonance spectroscopy. At the end of the separation process of the five identified substances, only the two dicarboxylic acids, maleic acid and succinic acid, had a significant (P fermented glucose, respectively), but not on gastrin release. When given together, they increased gastric acid output by 100% of fermented glucose and by 95% of maximal acid output. We therefore conclude that maleic acid and succinic acid are the powerful stimulants of gastric acid output in fermented glucose and alcoholic beverages produced by fermentation, and that gastrin is not their mediator of action.

  15. Effect of baseline plasma fatty acids on eicosapentaenoic acid levels in individuals supplemented with alpha-linolenic acid.

    Science.gov (United States)

    DeFilippis, Andrew P; Harper, Charles R; Cotsonis, George A; Jacobson, Terry A

    2009-01-01

    We previously reported a >50% increase in mean plasma eicosapentaenoic acid levels in a general medicine clinic population after supplementation with alpha-linolenic acid. In the current analysis, we evaluate the variability of changes in eicosapentaenoic acid levels among individuals supplemented with alpha-linolenic acid and evaluated the impact of baseline plasma fatty acids levels on changes in eicosapentaenoic acid levels in these individuals. Changes in eicosapentaenoic acid levels among individuals supplemented with alpha-linolenic acid ranged from a 55% decrease to a 967% increase. Baseline plasma fatty acids had no statistically significant effect on changes in eicosapentaenoic levels acid after alpha-linolenic acid supplementation. Changes in eicosapentaenoic acid levels varied considerably in a general internal medicine clinic population supplemented with alpha-linolenic acid. Factors that may impact changes in plasma eicosapentaenoic acid levels after alpha-linolenic acid supplementation warrant further study.

  16. Uric acid nephrolithiasis: An update.

    Science.gov (United States)

    Cicerello, Elisa

    2018-04-01

    Uric acid nephrolithiasis appears to increase in prevalence. While a relationship between uric acid stones and low urinary pH has been for long known, additional association with various metabolic conditions and pathophysiological basis has recently been elucidated. Some conditions such as diabetes and metabolic syndrome disease, excessive dietary intake, and increased endogenous uric acid production and/or defect in ammoniagenesis are associated with low urinary pH. In addition, the phenomenon of global warming could result in an increase in areas with greater climate risk for uric acid stone formation. There are three therapeutic steps to be taken for management of uric acid stones: identification of urinary pH profiles, assessment of urinary volume status, and identification of disorders leading to excessive uric acid production. However, the most important factor for uric acid stone formation is acid urinary pH, which is a prerequisite for uric acid precipitation. This article reviews recent insights into the pathophysiology of uric acid stones and their management.

  17. Dissociation of weak acids during Gran plot free acidity titrations

    OpenAIRE

    Lindberg, Steven E:; Cole, Jan M.

    2011-01-01

    A comparison of weak and free acid concentrations measured by base titration and hydrogen ionactivities determined by direct pH measurement is described for several of our data sets for raincollected above and below a forest canopy in the eastern United States. These data illustrate theinfluence of weak acid dissociation during titration and the possible effect of activity coefficientson calculated free acid concentrations.DOI: 10.1111/j.1600-0889.1984.tb00240.x

  18. Electrolytic nature of aqueous sulfuric acid. 2. Acidity.

    Science.gov (United States)

    Fraenkel, Dan

    2012-09-27

    In part 1 of this study, I reported that the Debye-Hückel limiting law and the smaller-ion shell (SiS) model of strong electrolyte solutions fit nicely with the experimental mean ionic activity coefficient (γ(±)) of aqueous sulfuric acid as a function of concentration and of temperature when the acid is assumed to be a strong 1-3 electrolyte. Here, I report that the SiS-derived activity coefficient of H(+), γ(H(+)), of the 1-3 acid is comparable to that of aqueous HCl. This agrees with titration curves showing, as well-known, that sulfuric acid in water is parallel in strength to aqueous HCl. The calculated pH is in good accord with the Hammett acidity function, H(0), of aqueous sulfuric acid at low concentration, and differences between the two functions at high concentration are discussed and explained. This pH-H(0) relation is consistent with the literature showing that the H(0) of sulfuric acid (in the 1-9 M range) is similar to those of HCl and the other strong mineral monoprotic acids. The titration of aqueous sulfuric acid with NaOH does not agree with the known second dissociation constant of 0.010 23; rather, the constant is found to be ~0.32 and the acid behaves upon neutralization as a strong diprotic acid practically dissociating in one step. A plausible reaction pathway is offered to explain how the acid may transform, upon base neutralization, from a dissociated H(4)SO(5) (as 3H(+) and HSO(5)(3-)) to a dissociated H(2)SO(4) even though the equilibrium constant of the reaction H(+) + HSO(5)(3-) ↔ SO(4)(2-) + H(2)O, at 25 °C, is 10(-37) (part 1).

  19. Adipic acid tolerance screening for potential adipic acid production hosts

    OpenAIRE

    Karlsson, Emma; Mapelli, Valeria; Olsson, Lisbeth

    2017-01-01

    Background Biobased processes for the production of adipic acid are of great interest to replace the current environmentally detrimental petrochemical production route. No efficient natural producer of adipic acid has yet been identified, but several approaches for pathway engineering have been established. Research has demonstrated that the microbial production of adipic acid is possible, but the yields and titres achieved so far are inadequate for commercialisation. A plausible explanation ...

  20. Counter current extraction of phosphoric acid: Food grade acid production

    International Nuclear Information System (INIS)

    Shlewit, H.; AlIbrahim, M.

    2009-01-01

    Extraction, scrubbing and stripping of phosphoric acid from the Syrian wet-phosphoric acid was carried out using Micro-pilot plant of mixer settler type of 8 l/h capacity. Tributyl phosphate (TBP)/di-isopropyl ether (DIPE) in kerosene was used as extractant. Extraction and stripping equilibrium curves were evaluated. The number of extraction and stripping stages to achieve the convenient and feasible yield was determined. Detailed flow sheet was suggested for the proposed continuous process. Data obtained include useful information for the design of phosphoric acid extraction plant. The produced phosphoric acid was characterized using different analytical techniques. (author)

  1. Phytanic acid metabolism in health and disease

    NARCIS (Netherlands)

    Wanders, Ronald J. A.; Komen, Jasper; Ferdinandusse, Sacha

    2011-01-01

    Phytanic acid (3,7,11,15-tetramethylhexadecanoic acid) is a branched-chain fatty acid which cannot be beta-oxidized due to the presence of the first methyl group at the 3-position. Instead, phytanic acid undergoes alpha-oxidation to produce pristanic acid (2,6,10,14-tetramethylpentadecanoic acid)

  2. 49 CFR 173.158 - Nitric acid.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Nitric acid. 173.158 Section 173.158... Nitric acid. (a) Nitric acid exceeding 40 percent concentration may not be packaged with any other material. (b) Nitric acid in any concentration which does not contain sulfuric acid or hydrochloric acid as...

  3. Acid mine drainage

    Science.gov (United States)

    Bigham, Jerry M.; Cravotta, Charles A.

    2016-01-01

    Acid mine drainage (AMD) consists of metal-laden solutions produced by the oxidative dissolution of iron sulfide minerals exposed to air, moisture, and acidophilic microbes during the mining of coal and metal deposits. The pH of AMD is usually in the range of 2–6, but mine-impacted waters at circumneutral pH (5–8) are also common. Mine drainage usually contains elevated concentrations of sulfate, iron, aluminum, and other potentially toxic metals leached from rock that hydrolyze and coprecipitate to form rust-colored encrustations or sediments. When AMD is discharged into surface waters or groundwaters, degradation of water quality, injury to aquatic life, and corrosion or encrustation of engineered structures can occur for substantial distances. Prevention and remediation strategies should consider the biogeochemical complexity of the system, the longevity of AMD pollution, the predictive power of geochemical modeling, and the full range of available field technologies for problem mitigation.

  4. Synthesis of aminoaldonic acids

    DEFF Research Database (Denmark)

    Jørgensen, Christel Thea

    With the aim of synthesising aminoaldonic acids, two 2-acetamido-2-deoxyaldonolactones with D-galacto (6) and D-arabino (11) configuration were prepared from acetylated sugar formazans in analogy with a known procedure. Empolying the same procedure to acetylated sugar phenylhydrazones gave mixtures......,4-lactone, respectively. A 2,3-aziridino-2,3-dideoxypentonamide 70 was also prepared from D-glucono-1,5-lactone. The lactones were converted into methyl 3,4-O-isopropylidene-2-O-sulfonyl esters 42, 50, 62 and 68, which upon treatment with concentrated aqueous ammonia yielded the aziridino compounds...... and 82, respectively. The aminolactone 84 was converted into the corresponding amino sugar 89.With the aim of synthesising substrates for the Pictet-Spengler reaction three 4-aldehydo acetamidodideoxytetronolactones 92, 97 and 103 were prepared by periodate cleavage of the corresponding hexonolactones...

  5. Uranium extraction from phosphoric acid

    International Nuclear Information System (INIS)

    Araujo Figueiredo, C. de

    1984-01-01

    The recovery of uranium from phosphoric liquor by two extraction process is studied. First, uranium is reduced to tetravalent condition and is extracted by dioctypyrophosphoric acid. The re-extraction is made by concentrated phosphoric acid with an oxidizing agent. The re-extract is submitted to the second process and uranium is extracted by di-ethylhexilphosphoric acid and trioctylphosphine oxide. (M.A.C.) [pt

  6. Acid digestion of organic materials

    International Nuclear Information System (INIS)

    Capp, P.D.

    1988-01-01

    To overcome the high temperatures involved in straight incineration of organic waste and the difficulty of extracting actinides from the ash various research establishments throughout the world, including Winfrith and Harwell in the UK, have carried out studies on an alternative chemical combustion method known as acid digestion. The basis of the technique is to digest the waste in concentrated sulphuric acid containing a few percent of nitric acid at a temperature of about 250 0 C. Acid digestion residues consist mainly of non-refractory inorganic sulphates and oxides from which any actinide materials can easily be extracted. (author)

  7. Antibiofilm Properties of Acetic Acid

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Alhede, Morten; Jensen, Peter Østrup

    2014-01-01

    of the infected implant, tissue, or organ and thereby the biofilm. Acetic acid is known for its antimicrobial effect on bacteria in general, but has never been thoroughly tested for its efficacy against bacterial biofilms. In this article, we describe complete eradication of both Gram-positive and Gram......-negative biofilms using acetic acid both as a liquid and as a dry salt. In addition, we present our clinical experience of acetic acid treatment of chronic wounds. In conclusion, we here present the first comprehensive in vitro and in vivo testing of acetic acid against bacterial biofilms....

  8. ACETIC ACID AND A BUFFER

    DEFF Research Database (Denmark)

    2009-01-01

    The present invention relates to a composition comprising : a) 0.01-20% wt/wt acetic acid and b) a physiologically tolerable buffer capable of maintaining acetic acid at a pH in the range of 2-7; and use of such a composition as an antimicrobial agent.......The present invention relates to a composition comprising : a) 0.01-20% wt/wt acetic acid and b) a physiologically tolerable buffer capable of maintaining acetic acid at a pH in the range of 2-7; and use of such a composition as an antimicrobial agent....

  9. Kinetics of oxidation of acidic amino acids by sodium N ...

    Indian Academy of Sciences (India)

    Unknown

    ... the mechanism of amino acids metabolism. Amino acids find a number of applications in biochemical research, metabolism, microbiology, nutrition, pharmaceuticals and fortification of foods and feeds. Generally only the amino and carboxyl functional groups in RCH(NH2)COOH undergo chemical transformations while.

  10. How salicylic acid takes transcriptional control over jasmonic acid signaling

    NARCIS (Netherlands)

    Caarls, Lotte|info:eu-repo/dai/nl/371746213; Pieterse, Corné M J|info:eu-repo/dai/nl/113115113; van Wees, Saskia C M|info:eu-repo/dai/nl/185445373

    2015-01-01

    Transcriptional regulation is a central process in plant immunity. The induction or repression of defense genes is orchestrated by signaling networks that are directed by plant hormones of which salicylic acid (SA) and jasmonic acid (JA) are the major players. Extensive cross-communication between

  11. Lipoic acid and diabetes: Effect of dihydrolipoic acid administration ...

    Indian Academy of Sciences (India)

    Relative α-lipoic acid content of diabetic livers was considerably less than that of normal livers as determined by gas chromatography. It was not possible to detect any dihydrolipoic acid in the livers. Biochemical abnormalities such as hyperglycaemia, ketonemia, reduction in liver glycogen and impaired incorporation of ...

  12. Amino acids analysis during lactic acid fermentation by single strain ...

    African Journals Online (AJOL)

    SAM

    2014-07-09

    Jul 9, 2014 ... Amino acids analysis during lactic acid fermentation by single strain cultures of lactobacilli and mixed culture starter made from them. KiBeom Lee1*, Ho-Jin Kim1 and Sang-Kyu Park2. 1Bio Center Technopark, 7-50 Songdo, Yeonsu-Gu, Incheon 406-840, Republic of Korea. 2Nambu University, Chumdan ...

  13. Fatty Acid Desaturases, Polyunsaturated Fatty Acid Regulation, and Biotechnological Advances

    Directory of Open Access Journals (Sweden)

    Je Min Lee

    2016-01-01

    Full Text Available Polyunsaturated fatty acids (PUFAs are considered to be critical nutrients to regulate human health and development, and numerous fatty acid desaturases play key roles in synthesizing PUFAs. Given the lack of delta-12 and -15 desaturases and the low levels of conversion to PUFAs, humans must consume some omega-3 and omega-6 fatty acids in their diet. Many studies on fatty acid desaturases as well as PUFAs have shown that fatty acid desaturase genes are closely related to different human physiological conditions. Since the first front-end desaturases from cyanobacteria were cloned, numerous desaturase genes have been identified and animals and plants have been genetically engineered to produce PUFAs such as eicosapentaenoic acid and docosahexaenoic acid. Recently, a biotechnological approach has been used to develop clinical treatments for human physiological conditions, including cancers and neurogenetic disorders. Thus, understanding the functions and regulation of PUFAs associated with human health and development by using biotechnology may facilitate the engineering of more advanced PUFA production and provide new insights into the complexity of fatty acid metabolism.

  14. Composition of amino acids, fatty acids and dietary fibre monomers ...

    African Journals Online (AJOL)

    There is increasing demand for sources of energy and non-meat protein with balanced amino acid profiles worldwide. Nuts are rich in protein and essential amino acids, and have a high energy value due to their high fat content. Kernels from two wild fruits in Mozambique, Adansonia digitata and Sclerocarya birrea, were ...

  15. Biopropionic acid production via molybdenumcatalyzed deoxygenation of lactic acid

    NARCIS (Netherlands)

    Korstanje, T.J.; Kleijn, H.; Jastrzebski, J.T.B.H.; Klein Gebbink, R.J.M.

    2013-01-01

    As the search for non-fossil based building blocks for the chemical industry increases, new methods for the deoxygenation of biomass-derived substrates are required. Here we present the deoxygenation of lactic acid to propionic acid, using a catalyst based on the non-noble and abundant metal

  16. Neuroexcitatory amino acids: 4-methylene glutamic acid derivatives : Short Communication.

    Science.gov (United States)

    Receveur, J M; Roumestant, M L; Viallefont, P

    1995-12-01

    A short synthesis of 4-methylene glutamic acid was achieved. Under thermal conditions the corresponding anhydride reacted with 2,3 dimethylbutadiene to afford the corresponding DIELS-ALDER adduct in good yield. L-4-methylene glutamic acid essentially acts on glutamate metabotropic receptors and is as potent as L-Glu in producing IPs.

  17. Nucleic Acid Backbone Structure Variations: Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    Nielsen, Peter E.

    2010-01-01

    Synthetic analogues and mimics of the natural genetic material deoxyribonucleic acid (DNA) are potential gene therapeutic (antisense or antigene) drugs. One of these mimics, peptide nucleic acids (PNAs), are chemically closer to peptides and proteins than to DNA, but nonetheless have retained many...

  18. Classifying Your Food as Acid, Low-Acid, or Acidified

    OpenAIRE

    Bacon, Karleigh

    2012-01-01

    As a food entrepreneur, you should be aware of how ingredients in your product make the food look, feel, and taste; as well as how the ingredients create environments for microorganisms like bacteria, yeast, and molds to survive and grow. This guide will help you classifying your food as acid, low-acid, or acidified.

  19. Formic acid assisted hydrogenation of levulinic acid to γ ...

    Indian Academy of Sciences (India)

    Vapor phase hydrogenation of levulinic acid using formic acid as a hydrogen source has been conducted over ordered mesoporous Cu/Fe2O3 catalysts prepared by hard template method using mesoporous silica, SBA-15. X-ray diffraction result reveals the absence of copper peaks because of either highly dispersed state, ...

  20. C-11 Acid and the Stereochemistry of Abietic Acid

    Indian Academy of Sciences (India)

    IAS Admin

    organic chemistry' and of the theoretical treatment of the chemical bond, essential to an understanding of how natural products are formed through biosynthetic processes (enzyme mediated synthe- sis of complex structures from substrates of primary structure). C-11 and C-12 Acids. Oxidation of abietic acid or its methyl ...

  1. Mechanisms and improvement of acid resistance in lactic acid bacteria.

    Science.gov (United States)

    Wang, Chao; Cui, Yanhua; Qu, Xiaojun

    2018-03-01

    Lactic acid bacteria (LAB) can take advantage of fermentable carbohydrates to produce lactic acid. They are proverbially applied in industry, agricultural production, animal husbandry, food enterprise, pharmaceutical engineering and some other important fields, which are closely related to human life. For performing the probiotic functions, LAB have to face the low pH environment of the gastrointestinal tract. Therefore, acid resistance of LAB is of great importance not only for their own growth, but also for fermentation and preparation of probiotic products. Recent research studies on acid resistance mechanisms of LAB are mainly focused on neutralization process, biofilm and cell density, proton pump, protection of macromolecules, pre-adaptation and cross-protection, and effect of solutes. In this context, biotechnological strategies such as synthetic biology, genome shuffling, high pressure homogenization and adaptive laboratory evolution were also used to improve the acid resistance of LAB to respond to constantly changing low pH environment.

  2. Carbonic Acid Pretreatment of Biomass

    Energy Technology Data Exchange (ETDEWEB)

    G. Peter van Walsum; Kemantha Jayawardhana; Damon Yourchisin; Robert McWilliams; Vanessa Castleberry

    2003-05-31

    This project sought to address six objectives, outlined below. The objectives were met through the completion of ten tasks. 1) Solidify the theoretical understanding of the binary CO2/H2O system at reaction temperatures and pressures. The thermodynamics of pH prediction have been improved to include a more rigorous treatment of non-ideal gas phases. However it was found that experimental attempts to confirm theoretical pH predictions were still off by a factor of about 1.8 pH units. Arrhenius experiments were carried out and the activation energy for carbonic acid appears to be substantially similar to sulfuric acid. Titration experiments have not yet confirmed or quantified the buffering or acid suppression effects of carbonic acid on biomass. 2) Modify the carbonic acid pretreatment severity function to include the effect of endogenous acid formation and carbonate buffering, if necessary. It was found that the existing severity functions serve adequately to account for endogenous acid production and carbonate effects. 3) Quantify the production of soluble carbohydrates at different reaction conditions and severity. Results show that carbonic acid has little effect on increasing soluble carbohydrate concentrations for pretreated aspen wood, compared to pretreatment with water alone. This appears to be connected to the release of endogenous acids by the substrate. A less acidic substrate such as corn stover would derive benefit from the use of carbonic acid. 4) Quantify the production of microbial inhibitors at selected reaction conditions and severity. It was found that the release of inhibitors was correlated to reaction severity and that carbonic acid did not appear to increase or decrease inhibition compared to pretreatment with water alone. 5) Assess the reactivity to enzymatic hydrolysis of material pretreated at selected reaction conditions and severity. Enzymatic hydrolysis rates increased with severity, but no advantage was detected for the use of carbonic

  3. Infrared spectra of hydrogen-bonded salicylic acid and its derivatives : Salicylic acid and acetylsalicylic acid

    Science.gov (United States)

    Wójcik, Marek J.

    1981-11-01

    Infrared spectra of hydrogen-bonded salicylic acid, O-deutero-salicylic acid and acetylsalicylic acid crystals have been studied experimentally and theoretically. Interpretation of these spectra was based on the Witkowski-Maréchal model. Semi-quantitative agreement between experimental and theoretical spectra can be achieved with the simplest form of this model, with values of interaction parameters transferable for equivalent intermolecular hydrogen bonds.

  4. Interaction of Polyamines, Abscisic Acid, Nitric Oxide, and Hydrogen Peroxide under Chilling Stress in Tomato (Lycopersicon esculentumMill.) Seedlings.

    Science.gov (United States)

    Diao, Qiannan; Song, Yongjun; Shi, Dongmei; Qi, Hongyan

    2017-01-01

    Polyamines (PAs) play a vital role in the responses of higher plants to abiotic stresses. However, only a limited number of studies have examined the interplay between PAs and signal molecules. The aim of this study was to elucidate the cross-talk among PAs, abscisic acid (ABA), nitric oxide (NO), and hydrogen peroxide (H 2 O 2 ) under chilling stress conditions using tomato seedlings [( Lycopersicon esculentum Mill.) cv. Moneymaker]. The study showed that during chilling stress (4°C; 0, 12, and 24 h), the application of spermidine (Spd) and spermine (Spm) elevated NO and H 2 O 2 levels, enhanced nitrite reductase (NR), nitric oxide synthase (NOS)-like, and polyamine oxidase activities, and upregulated LeNR relative expression, but did not influence LeNOS1 expression. In contrast, putrescine (Put) treatment had no obvious impact. During the recovery period (25/15°C, 10 h), the above-mentioned parameters induced by the application of PAs were restored to their control levels. Seedlings pretreated with sodium nitroprusside (SNP, an NO donor) showed elevated Put and Spd levels throughout the treatment period, consistent with increased expression in leaves of genes encoding arginine decarboxylase ( LeADC. LeADC1 ), ornithine decarboxylase ( LeODC ), and Spd synthase ( LeSPDS ) expressions in tomato leaves throughout the treatment period. Under chilling stress, the Put content increased first, followed by a rise in the Spd content. Exogenously applied SNP did not increase the expression of genes encoding S -adenosylmethionine decarboxylase ( LeSAMDC ) and Spm synthase ( LeSPMS ), consistent with the observation that Spm levels remained constant under chilling stress and during the recovery period. In contrast, exogenous Put significantly increased the ABA content and the 9- cis -epoxycarotenoid dioxygenase ( LeNCED1 ) transcript level. Treatment with ABA could alleviate the electrolyte leakage (EL) induced by D-Arg (an inhibitor of Put). Taken together, it is

  5. Origin of nucleic acids

    International Nuclear Information System (INIS)

    Prieur, B.E.

    1995-01-01

    The appearance of nucleic acids is the first event after the birth of membranes which made it possible to assure the perenniality of information. The complexity of these molecules has led some scientists to propose that they were not prebiotic but rather derived a more simple and achiral primitive ancestor. This hypothesis suggests that ribose possesses properties that allowed the formation of certain polysaccharides which evolved to RNA. The first step of the hypothesis is the selection and concentration of ribofuranose. This sugar has chelating properties and its alpha-ribofuranose is favoured in the chelating position. The density of the sugar with a heavy cation is greater than water and thus the complex can escape the UV radiation at the surface of the ocean. The particularity of ribose is to be able to form a homochiral regular array of these basic chelating structures with pyrophosphite. These arrays evolve towards the formation of polysaccharides (poly ribose phosphate) which have a very organized structure. These polysaccharides in turn evolve to RNA by binding of adenine and deoxyguanine which are HCN derivatives that can react with the polysaccharides. The primitive RNA is methylated and oxidized to form prebiotic RNA with adenosine, cytidine, 7methyl-guanosine and ribothymidine as nucleic bases. The pathway of biosynthesis of DNA form RNA will be studied. I suggest that the appearance of DNA results form the interaction between prebiotic double stranded RNA and proteins. DNA could be a product of RNA degradation by proteins. The catabolism of RNA to DNA requires a source of free radicals, protons and hydrides. RNA cannot produce free radicals, which are provided by the phenol group of the amino acid tyrosien. Protons are provided by the medium and hydrides are provided by 7-methyl-guanosine which can fix hydrides coming from hydrogen gas and donate them for the transformation of a riboside to a deoxyriboside. This pathway suggests that DNA appeared at

  6. Bile acids for viral hepatitis

    DEFF Research Database (Denmark)

    Chen, Weikeng; Liu, J; Gluud, C

    2003-01-01

    The viral hepatitides are common causes of liver diseases globally. Trials have assessed bile acids for patients with viral hepatitis, but no consensus was reached regarding their usefulness.......The viral hepatitides are common causes of liver diseases globally. Trials have assessed bile acids for patients with viral hepatitis, but no consensus was reached regarding their usefulness....

  7. Chloroacetic acids in environmental processes

    Czech Academy of Sciences Publication Activity Database

    Matucha, Miroslav; Gryndler, Milan; Forczek, Sándor; Uhlířová, H.; Fuksová, Květoslava; Schröder, P.

    2003-01-01

    Roč. 1, - (2003), s. 127-130 ISSN 1610-3653 R&D Projects: GA ČR GA522/02/0874 Institutional research plan: CEZ:AV0Z5038910 Keywords : Dichloroacetic acid * Trichloroacetic acid * Microbial degradation Subject RIV: GK - Forestry

  8. Ascorbic acid in bronchial asthma

    African Journals Online (AJOL)

    1983-04-23

    Apr 23, 1983 ... by comparing the pre-ascorbic acid results with those obtained 21/2 hours after the intravenous ... (ASO), C-reactive protein and antibodies to certain respiratory viruses. These investigations were ..... vitamin.6 However, other investigators were unable to detect any protective effects of ascorbic acid on the ...

  9. Getting Back to Basics (& Acidics)

    Science.gov (United States)

    Rhodes, Sam

    2006-01-01

    This article describes a few novel acid-base experiments intended to introduce students to the basic concepts of acid-base chemistry and provide practical examples that apply directly to the study of biology and the human body. Important concepts such as the reaction between carbon dioxide and water, buffers and protein denaturation, are covered.…

  10. 78 FR 20029 - Castor Oil, Polymer With Adipic Acid, Linoleic Acid, Oleic Acid and Ricinoleic Acid; Tolerance...

    Science.gov (United States)

    2013-04-03

    ... ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 180 [EPA-HQ-OPP-2013-0057; FRL-9381-2] Castor Oil... from the requirement of a tolerance for residues of castor oil, polymer with adipic acid, linoleic acid... eliminates the need to establish a maximum permissible level for residues of castor oil, polymer with adipic...

  11. Reactive extraction and recovery of levulinic acid, formic acid and furfural from aqueous solutions containing sulphuric acid

    NARCIS (Netherlands)

    Brouwer, Thomas; Blahusiak, Marek; Babic, Katarina; Schuur, Boelo

    2017-01-01

    Levulinic acid (LA) can be produced from lignocellulosic materials via hydroxylation followed by an acid-catalyzed conversion of hexoses. Inorganic homogeneous catalysts are mostly used, in particular sulphuric acid, yielding a mixture of LA with sulphuric acid, formic acid (FA) and furfural.

  12. Studies on radiolysis of amino acids, (4)

    International Nuclear Information System (INIS)

    Oku, Tadatake

    1978-01-01

    In order to elucidate the effect of adding methionine on the loss of amino acid by γ-irradiation in amino acid mixture, because methionine is one of the most radio-sensitive in amino acids, the remaining amino acids in γ-irradiated aqueous solution of amino acid mixture were studied by determining the total amount of each remaining amino acid. The mixture of 18 amino acids which contains methionine and that of 17 amino acids without methionine were used. Amino acids and the irradiation products were determined with an automatic amino acid analyzer. The total amount of remaining amino acids in the irradiated solution of 18 amino acid mixture was more than that of 17 amino acid mixture. The order of the total amount of each remaining amino acid by low-dose irradiation was Gly>Ala>Asp>Glu>Val>Ser, Pro>Ile, Leu>Thr>Lys>Tyr>Arg>His>Phe>Try>Cys>Met. In case of the comparison of amino acids of same kinds, the total remaining amount of each amino acid in amino acid mixture was more than that of individually irradiated amino acid. The total remaining amounts of glycine, alanine and aspartic acid in irradiated 17 amino acid mixture resulted in slight increase. Ninhydrin positive products formed from 18 amino acid mixture irradiated with 2.640 x 10 3 rad were ammonia, methionine sulfoxide and DOPA of 1.34, 0.001 and 0.25 μmoles/ml of the irradiated solution, respectively. (Kobake, H.)

  13. Valproic Acid-induced Agranulocytosis

    Directory of Open Access Journals (Sweden)

    Hui-Chuan Hsu

    2009-06-01

    Full Text Available Valproic acid is considered to be the most well-tolerated antiepileptic drug. However, few cases of neutropenia or leukopenia caused by valproic acid have been reported. We present a patient who took valproic acid to treat a complication of brain surgery and in whom severe agranulocytosis occurred after 2.5 months. Valproic acid was stopped immediately, and granulocyte colony-stimulating factor was administered for 2 days. The patient's white blood cell count returned to normal within 2 weeks. The result of bone marrow aspiration was compatible with drug-induced agranulocytosis. This case illustrates that patients who take valproic acid may need regular checking of complete blood cell count.

  14. Uric acid and evolution.

    Science.gov (United States)

    Álvarez-Lario, Bonifacio; Macarrón-Vicente, Jesús

    2010-11-01

    Uric acid (UA) is the end product of purine metabolism in humans due to the loss of uricase activity by various mutations of its gene during the Miocene epoch, which led to humans having higher UA levels than other mammals. Furthermore, 90% of UA filtered by the kidneys is reabsorbed, instead of being excreted. These facts suggest that evolution and physiology have not treated UA as a harmful waste product, but as something beneficial that has to be kept. This has led various researchers to think about the possible evolutionary advantages of the loss of uricase and the subsequent increase in UA levels. It has been argued that due to the powerful antioxidant activity of UA, the evolutionary benefit could be the increased life expectancy of hominids. For other authors, the loss of uricase and the increase in UA could be a mechanism to maintain blood pressure in times of very low salt ingestion. The oldest hypothesis associates the increase in UA with higher intelligence in humans. Finally, UA has protective effects against several neurodegenerative diseases, suggesting it could have interesting actions on neuronal development and function. These hypotheses are discussed from an evolutionary perspective and their clinical significance. UA has some obvious harmful effects, and some, not so well-known, beneficial effects as an antioxidant and neuroprotector.

  15. Phosphonic acid: preparation and applications

    Directory of Open Access Journals (Sweden)

    Charlotte M. Sevrain

    2017-10-01

    Full Text Available The phosphonic acid functional group, which is characterized by a phosphorus atom bonded to three oxygen atoms (two hydroxy groups and one P=O double bond and one carbon atom, is employed for many applications due to its structural analogy with the phosphate moiety or to its coordination or supramolecular properties. Phosphonic acids were used for their bioactive properties (drug, pro-drug, for bone targeting, for the design of supramolecular or hybrid materials, for the functionalization of surfaces, for analytical purposes, for medical imaging or as phosphoantigen. These applications are covering a large panel of research fields including chemistry, biology and physics thus making the synthesis of phosphonic acids a determinant question for numerous research projects. This review gives, first, an overview of the different fields of application of phosphonic acids that are illustrated with studies mainly selected over the last 20 years. Further, this review reports the different methods that can be used for the synthesis of phosphonic acids from dialkyl or diaryl phosphonate, from dichlorophosphine or dichlorophosphine oxide, from phosphonodiamide, or by oxidation of phosphinic acid. Direct methods that make use of phosphorous acid (H3PO3 and that produce a phosphonic acid functional group simultaneously to the formation of the P–C bond, are also surveyed. Among all these methods, the dealkylation of dialkyl phosphonates under either acidic conditions (HCl or using the McKenna procedure (a two-step reaction that makes use of bromotrimethylsilane followed by methanolysis constitute the best methods to prepare phosphonic acids.

  16. Studies on biphenyl disulphonic acid doped polyanilines: Synthesis ...

    Indian Academy of Sciences (India)

    zed protonic acids, such as camphorsulfonic acid, dodecyl- benzene sulfonic acid, para-toluene sulfonic acid, benzene sulfonic acid, sulfanilic acid, sulfamic acid, octyl-benzene sulfonic acid, sulfosalicylic acid or methane sulfonic acid as dopants (Epstein et al 1987; Li et al 1987; Dhawan and Trivedi 1991, 1992; Kobayashi ...

  17. Expression of sialic acids and other nonulosonic acids in Leptospira

    Directory of Open Access Journals (Sweden)

    Ricaldi N Jessica

    2012-08-01

    Full Text Available Abstract Background Sialic acids are negatively charged nine carbon backbone sugars expressed on mammalian cell surfaces. Sialic acids are part of a larger family of nonulosonic acid (NulO molecules that includes pseudaminic and legionaminic acids. Microbial expression of sialic acids and other nonulosonic acids has been shown to contribute to host-microbe interactions in a variety of contexts, including participation in colonization, immune subversion, and behaviors such as biofilm formation, autoagglutination and motility. Previous research has suggested that some spirochetes may also express these molecules. Results Here we use a combination of molecular tools to investigate the presence of NulO biosynthetic gene clusters among clinical and saprophytic isolates of the genus Leptospira. Polymerase chain reaction and Southern blotting suggested that a variety of leptospires encoded NulO biosynthetic pathways. High performance liquid chromatography and mass spectrometry analyses provided biochemical evidence that di-N-acetylated NulO molecules are expressed at relatively high levels by L. interrogans serovar Lai strain 55601, and at lower levels by L. alexanderi serovar Manhao and L. fainei serovar Hurstbridge. Endogenous expression of N-acetylneuraminic acid (Neu5Ac, the most common sialic acid was documented in L. interrogans serovar Copenhageni strain L1-130. Neu5Ac biosynthesis is also supported by a unique gene fusion event resulting in an enzyme with an N-terminal N-acetylneuraminic acid synthase domain and a C-terminal phosphatase domain. This gene fusion suggests that L. interrogans uses a Neu5Ac biosynthetic pathway more similar to animals than to other bacteria. Analysis of the composition and phylogeny of putative NulO biosynthetic gene clusters in L. interrogans serovar Lai and serovar Copenhageni revealed that both strains have complete biosynthetic pathways for legionamimic acid synthesis, a molecule with the same stereochemistry

  18. Analytical application of aminohydroxamic acids

    International Nuclear Information System (INIS)

    Fadl Elmoula, Abd ELfatah Abdella

    2000-11-01

    Anthranilic hydroxamic acid was prepared by coupling of methylanthranilate (prepared by esterification of anthranilic acid with methyl alcohol using the fisher-speir method) with freshly prepared hydroxylamine. The lignad was characterized by the usual reaction of hydroxamic acid with acidic V(V) and Fe(III) solutions that gives blood-red colour in amyl alcohol and deep-violet colour in aqueous solution, respectively. The absorbance of Fe(III)-hydroxamic acids complexes increases with increase of pH. In this study, the effect of pH on the absorbance of Fe(III)-anthranilic hydroxamic acid was in accordance with this trend. The maximum absorbance was obtained at pH 5.0 at maximum wavelength of 482 nm. For Cu(II)-anthranilic hydroxamic acid complex, the use of acidic basic pH lead to precipitation of Cu(II)-ligand complex. But when using buffer pH (acetic acid/sodium acetate) a clear green colour of Cu(II)-ligand complex was obtained. The maximum wavelength of 390 nm. V(V)-anthranilic hydroxamic acid complex was extracted in acidic medium in amyl alcohol at pH 2.0 because in aqueous solution V(V)-anthranilic hydroxamic acid complex has not clear colour. It was observed the the maximum extraction in acidic medium decrease sharply with the increasing of pH value. The maximum wavelength for maximum absorbance was recorded at 472 nm. V(V) interfered with determination of Fe(III)) above concentration of 2 ppm, whereas Cu(II) interferes slightly with the determination of Fe(III) ions even at a high concentration of the Cu(II) ions. Both Cu(II) and Ni(II) do not interfere with the determination of V(V) ions even at high concentrations, Fe(III) ion produced slight interference, while Mo(VI) ions have a pronounced interference. Both V(V) and Fe(III) ions interfered markedly with the determination of Cu(II) ions, and made impractical under conditions. However, the calibration curves for the three metal ions produced a practical linear dynamic range.(Author)

  19. 21 CFR 184.1007 - Aconitic acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Aconitic acid. 184.1007 Section 184.1007 Food and... Substances Affirmed as GRAS § 184.1007 Aconitic acid. (a) Aconitic acid (1,2,3-propenetricarboxylic acid... Ranunculaceae. Transaconitic acid can be isolated during sugarcane processing, by precipitation as the calcium...

  20. Mechanical cell disruption of Parachlorella kessleri microalgae: Impact on lipid fraction composition.

    Science.gov (United States)

    Clavijo Rivera, E; Montalescot, V; Viau, M; Drouin, D; Bourseau, P; Frappart, M; Monteux, C; Couallier, E

    2018-05-01

    Samples of nitrogen-starved Parachlorella kessleri containing intact cells (IC), cells ground by bead milling (BM), and cells subjected to high-pressure cell disruption (HPD), together with their supernatants after centrifugation, were compared for granulometry and lipid profiles. The effects of disruption on the lipid profile and organisation were evaluated. The quantity of lipids available for extraction increased with disruption, and up to 81% could be recovered in supernatants after centrifugation, but a marked reorganization occurred. The proportion of amphiphilic free fatty acids and lysophosphatidylcholine increased during disruption due to their release or owing to lipid degradation by enzymes or physical conditions. This effect was more marked in HPD than in BM. Lipids contained in the aqueous phase, after disruption and centrifugation, were enriched in unsaturated fatty acids, BM leading to larger droplets than HPD. The larger liquid lipid droplet would be easier to recover in the following downstream processing. Copyright © 2018 Elsevier Ltd. All rights reserved.