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Sample records for biphenyl dioxygenase genes

  1. 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...

  2. Structural characterization of Pandoraea pnomenusa B-356 biphenyl dioxygenase reveals features of potent polychlorinated biphenyl-degrading enzymes.

    Directory of Open Access Journals (Sweden)

    Christopher L Colbert

    Full Text Available The oxidative degradation of biphenyl and polychlorinated biphenyls (PCBs is initiated in Pandoraea pnomenusa B-356 by biphenyl dioxygenase (BPDO(B356. BPDO(B356, a heterohexameric (αβ(3 Rieske oxygenase (RO, catalyzes the insertion of dioxygen with stereo- and regioselectivity at the 2,3-carbons of biphenyl, and can transform a broad spectrum of PCB congeners. Here we present the X-ray crystal structures of BPDO(B356 with and without its substrate biphenyl 1.6-Å resolution for both structures. In both cases, the Fe(II has five ligands in a square pyramidal configuration: H233 Nε2, H239 Nε2, D386 Oδ1 and Oδ2, and a single water molecule. Analysis of the active sites of BPDO(B356 and related ROs revealed structural features that likely contribute to the superior PCB-degrading ability of certain BPDOs. First, the active site cavity readily accommodates biphenyl with minimal conformational rearrangement. Second, M231 was predicted to sterically interfere with binding of some PCBs, and substitution of this residue yielded variants that transform 2,2'-dichlorobiphenyl more effectively. Third, in addition to the volume and shape of the active site, residues at the active site entrance also apparently influence substrate preference. Finally, comparison of the conformation of the active site entrance loop among ROs provides a basis for a structure-based classification consistent with a phylogeny derived from amino acid sequence alignments.

  3. Absolute configuration-dependent epoxide formation from isoflavan-4-ol stereoisomers by biphenyl dioxygenase of Pseudomonas pseudoalcaligenes strain KF707.

    Science.gov (United States)

    Seo, Jiyoung; Kang, Su-Il; Won, Dongho; Kim, Mihyang; Ryu, Ji-Young; Kang, Suk-Woo; Um, Byung-Hun; Pan, Cheol-Ho; Ahn, Joong-Hoon; Chong, Youhoon; Kanaly, Robert A; Han, Jaehong; Hur, Hor-Gil

    2011-03-01

    Biphenyl dioxygenase from Pseudomonas pseudoalcaligenes strain KF707 expressed in Escherichia coli was found to exhibit monooxygenase activity toward four stereoisomers of isoflavan-4-ol. LC-MS and LC-NMR analyses of the metabolites revealed that the corresponding epoxides formed between C2' and C3' on the B-ring of each isoflavan-4-ol substrate were the sole products. The relative reactivity of the stereoisomers was found to be in the order: (3S,4S)-cis-isoflavan-4-ol > (3R,4S)-trans-isoflavan-4-ol > (3S,4R)-trans-isoflavan-4-ol > (3R,4R)-cis-isoflavan-4-ol and this likely depended upon the absolute configuration of the 4-OH group on the isoflavanols, as explained by an enzyme-substrate docking study. The epoxides produced from isoflavan-4-ols by P. pseudoalcaligenes strain KF707 were further abiotically transformed into pterocarpan, the molecular structure of which is commonly found as part of plant-protective phytoalexins, such as maackiain from Cicer arietinum and medicarpin from Medicago sativa.

  4. Structure of the human 4-hydroxyphenylpyruvic acid dioxygenase gene (HPD)

    Energy Technology Data Exchange (ETDEWEB)

    Awata, H.; Endo, F.; Matsuda, I. [Kumamoto Univ. (Japan)

    1994-10-01

    4-Hydroxyphenylpyruvic acid dioxygenase (HPD) is an important enzyme in tyrosine catabolism in most organisms. The activity of this enzyme is expressed mainly in the liver and developmentally regulated in mammals, and a genetic deficiency in this enzyme in humans and mice leads to hereditary tyrosinemia type 3. Using human HPD cDNA as a probe, a chromosomal gene related to HPD was isolated from human gene libraries. The human HPD gene is over 30 kb long and is split into 14 exons. The extract sizes and boundaries of exon blocks were determined, and all of the splice donor and acceptor sites conformed to the GT/AG rule. Analysis of the 5{prime} flanking sequence of the gene suggests that expression of the gene is regulated by hepatocyte-specific and liver-enriched transcription factors, as well as by hormones. These features of the 5{prime} flanking region of the gene are similar to those of other genes that are specifically expressed in hepatocytes and that are developmentally regulated. 41 refs., 2 figs., 1 tab.

  5. Trichloroethylene degradation by Escherichia coli containing the cloned Pseudomonas putida F1 toluene dioxygenase genes.

    OpenAIRE

    Zylstra, G J; Wackett, L P; Gibson, D T

    1989-01-01

    Toluene dioxygenase from Pseudomonas putida F1 has been implicated as an enzyme capable of degrading trichloroethylene. This has now been confirmed with Escherichia coli JM109(pDTG601) that contains the structural genes (todC1C2BA) of toluene dioxygenase under the control of the tac promoter. The extent of trichloroethylene degradation by the recombinant organism depended on the cell concentration and the concentration of trichloroethylene. A linear rate of trichloroethylene degradation was o...

  6. Molecular Cloning and Characterization of a New Cold-active Extradiol Dioxygenase from a Metagenomic Library Derived from Polychlorinated Biphenyl-contaminated Soil

    Institute of Scientific and Technical Information of China (English)

    REN He-jun; LU Yang; ZHOU Rui; DAI Chun-yan; WANG Yan; ZHANG Lan-ying

    2012-01-01

    To find new extradiol dioxygenases(EDOs,EC 1.13.11.2),a metagenomics library was constructed from polychlorinated biphenyl-contaminated soil and was screened for some dioxygenase with aromatic ring cleavage activity.A novel EDO,designated as BphC_A,was identified and heterologously expressed in Escherichia coli.The deduced amino acid sequence of BphC_A exhibited a homology of less than 60% with other known EDOs.Phylogenetic analysis of BphC_A suggests that the protein is a novel member of the EDO family.The enzyme exhibits higher substrate affinity and catalytic efficiency toward 3-methylcatechol than toward 2,3-dihydroxybiphenyl or catechol,the preferred substrate of other known EDOs.The optimum activity of purified BphC_A occurred at pH=8.5 and 35 ℃,and BphC_A showed more than 40% of its initial activity at 5 ℃.The activity of purified BphC_A was significantly induced by Mn2+ and slightly reduced bv Al3+,Cu2+ and Zn2+.

  7. [Isolation, charcaterization of an anthracene degrading bacterium Martelella sp. AD-3 and cloning of dioxygenase gene].

    Science.gov (United States)

    Cui, Chang-Zheng; Feng, Tian-Cai; Yu, Ya-Qi; Dong, Fei; Yang, Xin-Mei; Feng, Yao-Yu; Liu, Yong-Di; Lin, Han-Ping

    2012-11-01

    Anthracene, among the 16 US EPA polycyclic aromatic hydrocarbons (PAHs), is a typical low molecular weight environmental contaminant, which gains concern on its biodegradation under hypersaline condition. In this study, an anthracene-degrading bacterial strain was isolated from highly saline petroleum-contaminated soil. Based on its physiological, biochemical characteristics and 16S rDNA sequence analysis, the bacteria was preliminary identified and named as Martelella sp. AD-3. The strain was able to utilize anthracene as sole carbon source for growth and the degradation occurred under broad salinities (0.1% to 10%) and varying pHs (6.0 to 10.0). The optimized degradation conditions were initial concentration 25 mg x L(-1), culture temperature 30 degrees C, pH 9.0 and salinity 3%. And 94.6% of anthracene was degraded by strain AD-3 under the optimal conditions within 6 days. Degenerate primers design was performed with a reported dioxygenase alpha subunit homologous gene. A length of 307 bp fragment of the partial dioxygenase gene sequences (GenBank accession: JF823991.1) was amplified by nested PCR. The clones amino acid sequence from strain AD-3 showed 95% identity to that of the partial naphthalene dioxygenase large-subunit from Marinobacter sp. NCE312 (AF295033). The results lay a foundation for the further study of molecular mechanism involved in the PAHs biodegradation by strain AD-3.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-02-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, M.; Khanna, S. [NIIT Univ, Neemrana (India). Dept. of Biotechnology & Bioinformation

    2010-04-15

    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 122-122.5 mg g{sup -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 (2Fe2S) 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.

  10. Isolation and characteristics of a novel biphenyl-degrading bacterial strain, Dyella ginsengisoli LA-4

    Institute of Scientific and Technical Information of China (English)

    LI Ang; QU Yuanyuan; ZHOU Jiti; GOU Min

    2009-01-01

    A novel biphenyl-degrading bacterial strain LA-4 was isolated from activated sludge. It was identified as Dyella ginsengisoli according to phylogenetic similarity of 16S rRNA gene sequence. This isolate could utilize biphenyl as sole source of carbon and energy, which degraded over 95 mg/L biphenyl within 36 h. The major metabolites formed from biphenyl, such as 2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoic acid (HOPDA) and benzoic acid, were identified by LC-MS. The crude cell extract of strain LA-4 exhibited the activity of 2,3-dihydroxybiphenyl 1,2-dioxygenase (2,3-DHBD) and the kinetic parameters were Km= 26.48 μmol/L and Vmax= 8.12 μmol/mg protein. A conserved region of the biphenyl dioxygenase gene bphA1 of strain LA-4 was amplified by PCR and confirmed by DNA sequencing.

  11. Mutations in the 4-hydroxyphenylpyruvate dioxygenase gene (HPD) in patients with tyrosinemia type III.

    Science.gov (United States)

    Rüetschi, U; Cerone, R; Pérez-Cerda, C; Schiaffino, M C; Standing, S; Ugarte, M; Holme, E

    2000-06-01

    Tyrosinemia type III (OMIM 276710) is an autosomal recessive disorder caused by the deficiency of 4-hydroxyphenylpyruvate dioxygenase (HPD), the second enzyme in the tyrosine catabolic pathway. The enzyme deficiency results in an accumulation and increased excretion of tyrosine and phenolic metabolites. Only a few cases with the disorder have been described, and the clinical spectrum of the disorder is unknown. Reported patients have presented with mental retardation or neurological symptoms or have been picked up by neonatal screening. We have identified four presumed pathogenic mutations (two missense and two nonsense mutations) in the HPD gene in three unrelated families encompassing four homozygous individuals and one compound heterozygous individual with tyrosinemia type III. Furthermore, a number of polymorphic mutations have been identified in the HPD gene. No correlation of the severity of the mutation and enzyme deficiency and mental function has been found; neither do the recorded tyrosine levels correlate with the clinical phenotype.

  12. 2,3-Dihydroxybiphenyl dioxygenase gene was first discovered in Arthrobacter sp. strain P J3

    Institute of Scientific and Technical Information of China (English)

    YANG MeiYing; MA PengDa; LI WenMing; LIU JinYing; LI Liang; ZHU XiaoJuan; WANG XingZhi

    2007-01-01

    Bacterium strain PJ3, isolated from wastewater and identified as Arthrobacter sp. bacterium based on its 16S rDNA gene, could use carbazole as the sole carbon, nitrogen and energy source. The genomic libraryof strain PJ3 was constructed and a positive clone JM109 (pUCW402) was screened out for the expression of dioxygenase by the ability to form yellow ring-fission product. A 2,3-dihydroxybiphenyl dioxygenase (23DHBD) gene of 933 bp was found in the 3360 bp exogenous fragment of pUCW402 by GenSCAN software and BLAST analysis. The phylogenetic analysis showed that 23DHBD from strain PJ3 formed a deep branch separate from a cluster containing most known 23DHBD in GenBank.Southern hybridization confirmed for the first time that the 23DHBD gene was from the genomic DNA of Arthrobacter sp. PJ3. In order to test the gene function, recombinant bacterium BL21 (pETW-8) was constructed to express 23DHBD. The expression level in BL21 (pETW-8) was highest compared with the recombinant bacteria JM109 (pUCW402) and strain PJ3. We observed that 23DHBD was not absolute specific. The enzyme activity was higher with 2,3-dihydroxybiphenyl as a substrate than with catechol.The substrate specificity assay suggested that 23DHBD was essential for cleavage of bi-cyclic aromatic compounds during the course of aromatic compound biodegradation in Arthrobacter sp. strain PJ3.

  13. Indoleamine 2,3-dioxygenase attenuates inhibitor development in gene-therapy-treated hemophilia A mice.

    Science.gov (United States)

    Liu, L; Liu, H; Mah, C; Fletcher, B S

    2009-06-01

    A serious impediment to gene and protein replacement therapy in hemophilia A is the development of inhibitors. Mechanisms responsible for inhibitor development include T-cell-dependent adaptive immune responses and the CD28-B7 signaling pathway that eventually leads to the formation of antibodies directed against factor VIII (FVIII). Indoleamine 2,3-dioxygenase (IDO) is a potent immunosuppressive enzyme that can inhibit T-cell responses and induce T-cell apoptosis by regulation of tryptophan metabolism. Kynurenine, one of the metabolites of tryptophan, has been implicated as an immune modulator. Here we hypothesize that co-delivery of the genes for FVIII and IDO can attenuate inhibitor formation. Using transposon-based gene delivery, we observed long-term therapeutic FVIII expression and significantly reduced inhibitor titers when the genes were co-delivered. Co-expression of FVIII and IDO in the liver was associated with increased plasma kynurenine levels, an inhibition of T-cell infiltration and increased apoptosis of T cells within the liver. These experiments suggest that modulation of tryptophan catabolism through IDO expression provides a novel strategy to reduce inhibitor development in hemophilia gene/protein therapy.

  14. Structure of 4-hydrophenylpyruvic acid dioxygenase (HPD) gene and its mutation in tyrosinemic mouse strain III

    Energy Technology Data Exchange (ETDEWEB)

    Awata, H.; Endo, F.; Matsuda, I. [Kumamoto Univ. Medical School (Japan)] [and others

    1994-09-01

    4-Hydroxphenylpyruvic acid dioxygenase (HPD) is an important enzyme in tyrosine catabolism in most organisms. The activity of this enzyme is expressed mainly in the liver and is developmentally regulated in mammals. A genetic deficiency of the enzyme in man and mouse leads to hereditary tyrosinemia type 3. Using human HPD cDNA as a probe, a chromosomal gene related to HPD was isolated from human and mouse gene libraries. The human HPD gene is over 30 kilo-bases long and is split into 14 exons. Analysis of the 5{prime} flanking sequence of the gene suggests that expression of the gene is regulated by hepatocyte-specific and liver-enriched transcription factors, as well as by hormones. These features of the 5{prime} flanking region of the gene are similar to those of other genes which are specifically expressed in hepatocytes and which are developmentally regulated. The gene for mouse HPD has a similar structure and we obtained evidence for a nucleotide substitution which generates a termination codon in exon 7 of the HPD gene in III mice. This mutation associates a partial exon skipping and most of the mRNA lacks sequences corresponding to exon 7. The partial exon skipping apparently is the result of a nonsense mutation in the exon. Thus, mouse strain III can serve as a genetic model for human tyrosinemia type 3. Ongoing studies are expected to elucidate the disease process involved in hereditary tyrosinemia type 1 and to shed light on mechanisms that mediate developmental regulation of HPD gene expression. In addition, mouse strain III together with recently established models for tyrosinemia type 1 will facilitate studies on hereditary tyrosinemias.

  15. 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.

  16. Novel aromatic ring-hydroxylating dioxygenase genes from coastal marine sediments of Patagonia

    Directory of Open Access Journals (Sweden)

    Ferrero Marcela A

    2008-03-01

    Full Text Available Abstract Background Polycyclic aromatic hydrocarbons (PAHs, widespread pollutants in the marine environment, can produce adverse effects in marine organisms and can be transferred to humans through seafood. Our knowledge of PAH-degrading bacterial populations in the marine environment is still very limited, and mainly originates from studies of cultured bacteria. In this work, genes coding catabolic enzymes from PAH-biodegradation pathways were characterized in coastal sediments of Patagonia with different levels of PAH contamination. Results Genes encoding for the catalytic alpha subunit of aromatic ring-hydroxylating dioxygenases (ARHDs were amplified from intertidal sediment samples using two different primer sets. Products were cloned and screened by restriction fragment length polymorphism analysis. Clones representing each restriction pattern were selected in each library for sequencing. A total of 500 clones were screened in 9 gene libraries, and 193 clones were sequenced. Libraries contained one to five different ARHD gene types, and this number was correlated with the number of PAHs found in the samples above the quantification limit (r = 0.834, p nahAc-like genes, phnAc-like genes as identified in Alcaligenes faecalis AFK2, and phnA1-like genes from marine PAH-degraders from the genus Cycloclasticus. Conclusion These results show the presence of hitherto unidentified ARHD genes in this sub-Antarctic marine environment exposed to anthropogenic contamination. This information can be used to study the geographical distribution and ecological significance of bacterial populations carrying these genes, and to design molecular assays to monitor the progress and effectiveness of remediation technologies.

  17. Mutations in the 4-hydroxyphenylpyruvic acid dioxygenase gene are responsible for tyrosinemia type III and hawkinsinuria.

    Science.gov (United States)

    Tomoeda, K; Awata, H; Matsuura, T; Matsuda, I; Ploechl, E; Milovac, T; Boneh, A; Scott, C R; Danks, D M; Endo, F

    2000-11-01

    The enzyme 4-hydroxyphenylpyruvic acid dioxygenase (HPD) catalyzes the reaction of 4-hydroxyphenylpyruvic acid to homogentisic acid in the tyrosine catabolism pathway. A deficiency in the catalytic activity of HPD may lead to tyrosinemia type III, an autosomal recessive disorder characterized by elevated levels of blood tyrosine and massive excretion of tyrosine derivatives into urine. It has been postulated that hawkinsinuria, an autosomal dominant disorder characterized by the excretion of 'hawkinsin,' may also be a result of HPD deficiency. Hawkinsin is a sulfur amino acid identified as (2-l-cystein-S-yl, 4-dihydroxycyclohex-5-en-1-yl)acetic acid. Patients with hawkinsinuria excrete this metabolite in their urine throughout their life, although symptoms of metabolic acidosis and tyrosinemia improve in the first year of life. We performed analyses of the HPD gene in a patient with tyrosinemia type III and two unrelated patients with hawkinsinuria. A homozygous missense mutation predicting an Ala to Val change at codon 268 (A268V) in the HPD gene was found in the patient with tyrosinemia type III. A heterozygous missense mutation predicting an Ala to Thr change at codon 33 (A33T) was found in the same HPD gene in the two patients with hawkinsinuria. These findings support the hypothesis that alterations in the structure and activity of HPD are causally related to two different metabolic disorders, tyrosinemia type III and hawkinsinuria.

  18. The gene coding for the DOPA dioxygenase involved in betalain biosynthesis in Amanita muscaria and its regulation.

    Science.gov (United States)

    Hinz, U G; Fivaz, J; Girod, P A; Zyrd, J P

    1997-09-01

    Genomic and cDNA clones derived from the gene (dodA) coding for DOPA dioxygenase, a key enzyme in the betalain pathway, were obtained from the basidiomycete Amanita muscaria. A cDNA library was established in the phage lambda ZapII and dodA clones were isolated using polyclonal antibodies raised against the purified enzyme. Their identity was confirmed by comparison of the deduced amino acid sequence with the sequence of several tryptic peptide fragments of DOPA dioxygenase. The gene coded for a 228-amino acid protein that showed no homology to published sequences. The coding region was interrupted by five short introns. Regulation was shown to occur at the transcriptional level; the mRNA accumulated to high levels only in the coloured cap tissue. dodA was found to be a single-copy gene in A. muscaria. To our knowledge, this is the first gene from the betalain pathway to be cloned. It encodes a type of aromatic ring-cleaving dioxygenase that has not been previously described.

  19. Aerobic degradation of polychlorinated biphenyls

    Energy Technology Data Exchange (ETDEWEB)

    Pieper, D.H. [Dept. of Environmental Microbiology, German Research Center for Biotechnology, Braunschweig (Germany)

    2005-04-01

    The microbial degradation of polychlorinated biphenyls (PCBs) has been extensively studied in recent years. The genetic organization of biphenyl catabolic genes has been elucidated in various groups of microorganisms, their structures have been analyzed with respect to their evolutionary relationships, and new information on mobile elements has become available. Key enzymes, specifically biphenyl 2,3-dioxygenases, have been intensively characterized, structure/sequence relationships have been determined and enzymes optimized for PCB transformation. However, due to the complex metabolic network responsible for PCB degradation, optimizing degradation by single bacterial species is necessarily limited. As PCBs are usually not mineralized by biphenyl-degrading organisms, and cometabolism can result in the formation of toxic metabolites, the degradation of chlorobenzoates has received special attention. A broad set of bacterial strategies to degrade chlorobenzoates has recently been elucidated, including new pathways for the degradation of chlorocatechols as central intermediates of various chloroaromatic catabolic pathways. To optimize PCB degradation in the environment beyond these metabolic limitations, enhancing degradation in the rhizosphere has been suggested, in addition to the application of surfactants to overcome bioavailability barriers. However, further research is necessary to understand the complex interactions between soil/sediment, pollutant, surfactant and microorganisms in different environments. (orig.)

  20. Identification of novel extracellular protein for PCB/biphenyl metabolism in Rhodococcus jostii RHA1.

    Science.gov (United States)

    Atago, Yuki; Shimodaira, Jun; Araki, Naoto; Bin Othman, Nor'azizi; Zakaria, Zuriati; Fukuda, Masao; Futami, Junichiro; Hara, Hirofumi

    2016-05-01

    Rhodococcus jostii RHA1 (RHA1) degrades polychlorinated biphenyl (PCB) via co-metabolism with biphenyl. To identify the novel open reading frames (ORFs) that contribute to PCB/biphenyl metabolism in RHA1, we compared chromatin immunoprecipitation chip and transcriptomic data. Six novel ORFs involved in PCB/biphenyl metabolism were identified. Gene deletion mutants of these 6 ORFs were made and were tested for their ability to grow on biphenyl. Interestingly, only the ro10225 deletion mutant showed deficient growth on biphenyl. Analysis of Ro10225 protein function showed that growth of the ro10225 deletion mutant on biphenyl was recovered when exogenous recombinant Ro10225 protein was added to the culture medium. Although Ro10225 protein has no putative secretion signal sequence, partially degraded Ro10225 protein was detected in conditioned medium from wild-type RHA1 grown on biphenyl. This Ro10225 fragment appeared to form a complex with another PCB/biphenyl oxidation enzyme. These results indicated that Ro10225 protein is essential for the formation of the PCB/biphenyl dioxygenase complex in RHA1.

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

    Science.gov (United States)

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

    2013-01-01

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

  2. A nonsense mutation in the 4-hydroxyphenylpyruvic acid dioxygenase gene (Hpd) causes skipping of the constitutive exon and hypertyrosinemia in mouse strain III

    Energy Technology Data Exchange (ETDEWEB)

    Endo, Fumio; Awata, Hisataka; Matsuda, Ichiro [Kumamoto Univ. (Japan)

    1995-01-01

    4-Hydroxyphenylpyruvic acid dioxygenase (HPD; EC 1.13.11.27) is an important enzyme in tyrosine catabolism in most organisms. Decreased activity of 4-hydroxyphenylpyruvic acid dioxygenase in the liver of mouse strain III is associated with tyrosinemia. We report a nucleotide substitution that generates a termination codon in exon 7 of the 4-hydroxyphenylpyruvic acid dioxygenase gene in III mice. This mutation is associated with partial exon skipping, and most of the mRNA lacks sequences corresponding to exon 7. The partial exon skipping apparently is the result of a nonsense mutation in the exon. Mouse strain III is a model for human tyrosinemia type 3 (McKusick 276710), and this train together with recently established models for tyrosinemia type 1 will facilitate studies of hereditary tyrosinemias.

  3. A nonsense mutation in the 4-hydroxyphenylpyruvic acid dioxygenase gene (Hpd) causes skipping of the constitutive exon and hypertyrosinemia in mouse strain III.

    Science.gov (United States)

    Endo, F; Awata, H; Katoh, H; Matsuda, I

    1995-01-01

    4-Hydroxyphenylpyruvic acid dioxygenase (HPD; EC 1.13.11.27) is an important enzyme in tyrosine catabolism in most organisms. Decreased activity of 4-hydroxyphenylpyruvic acid dioxygenase in the liver of mouse strain III is associated with tyrosinemia. We report a nucleotide substitution that generates a termination codon in exon 7 of the 4-hydroxyphenylpyruvic acid dioxygenase gene in III mice. This mutation is associated with partial exon skipping, and most of the mRNA lacks sequences corresponding to exon 7. The partial exon skipping apparently is the result of a nonsense mutation in the exon. Mouse strain III is a model for human tyrosinemia type 3 (McKusick 276710), and this strain together with recently established models for tyrosinemia type 1 will facilitate studies of hereditary tyrosinemias.

  4. Oxidation of chlorinated olefins by Escherichia coli transformed with dimethyl sulfide monooxygenase genes or cumene dioxygenase genes.

    Science.gov (United States)

    Takami, Wako; Yoshida, Takako; Nojiri, Hideaki; Yamane, Hisakazu; Omori, Toshio

    1999-04-01

    In the present work, it was shown that the dimethyl sulfide (DMS) monooxygenase and the cumene dioxygenase catalyzed oxidation of various chlorinated ethenes, propenes, and butenes. The specific activities of these oxygenases were determined for C(2) to C(4) chlorinated olefins, and the oxidation rates ranged from 0.19 to 4.18 nmol.min(-1).mg(-1) of dry cells by the DMS monooxygenase and from 0.19 to 1.29 nmol.min(-1).mg(-1) of dry cells by the cumene dioxygenase. The oxidation products were identified by gas chromatography-mass spectrometry. Most chlorinated olefins were monooxygenated by the DMS monooxygenase to yield chlorinated epoxides. In the case of the cumene dioxygenase, the substrates lacking any chlorine atom on double-bond carbon atoms were dioxygenated, and those with chlorine atoms attaching to double-bond carbon atoms were monooxygenated to yield allyl alcohols.

  5. Localization of the human indoleamine 2,3-dioxygenase (IDO) gene to the pericentromeric region of human chromosome 8

    Energy Technology Data Exchange (ETDEWEB)

    Burkin, D.J.; Jones, C. (Eleanor Roosevelt Institute for Cancer Research, Denver, CO (United States)); Kimbro, K.S.; Taylor, M.W. (Indiana Univ., Bloomington, IN (United States)); Barr, B.L.; Gupta, S.L. (Hipple Cancer Research Center, Dayton, OH (United States))

    1993-07-01

    Indoleamine 2,3-dioxygenase (IDO) is the first enzyme in the catabolic pathway for tryptophan. This extrahepatic enzyme differs from the hepatic enzyme, tryptophan 2,3-dioxygenase (TDO), in molecular as well as enzymatic characteristics, although both enzymes catalyze the same reaction: cleavage of tryptophan into N-formylkynurenine. The induction of IDO by IFN-[gamma] plays a role in the antigrowth effect of IFN-[gamma] in cell cultures and in the inhibition of intracellular pathogens, e.g., Toxoplasma gondii and Chlamydia psittaci. Tryptophan is also the precursor for the synthesis of serotonin, and reduced levels of tryptophan and serotonin found in AIDS patients have been correlated with the presence of IFN-[gamma] and consequent elevation of IDO activity. The IDO enzyme has been purified and characterized, and its cDNA and genomic DNA clones have been isolated and analyzed. DNA from hybrid cells containing fragments of human chromosome 8 was used to determine the regional localization of the IDO gene on chromosome 8. The hybrids R30-5B and R30-2A contain 8p11 [yields] qter and 8q13 [yields] qter, respectively. Hybrid 229-3A contains the 8pter [yields] q11. The hybrid R30-2A was negative for the IDO gene, whereas R30-5B and 229-3A were positive as analyzed by PCR and verified by Southern blotting. Only the region close to the centromere is shared by R30-5B and 229-3A hybrids. The results indicate that the IDO gene is located on chromosome 8p11 [yields] q11.

  6. Redox proteins of hydroxylating bacterial dioxygenases establish a regulatory cascade that prevents gratuitous induction of tetralin biodegradation genes

    Science.gov (United States)

    Ledesma-García, Laura; Sánchez-Azqueta, Ana; Medina, Milagros; Reyes-Ramírez, Francisca; Santero, Eduardo

    2016-01-01

    Bacterial dioxygenase systems are multicomponent enzymes that catalyze the initial degradation of many environmentally hazardous compounds. In Sphingopyxis granuli strain TFA tetralin dioxygenase hydroxylates tetralin, an organic contaminant. It consists of a ferredoxin reductase (ThnA4), a ferredoxin (ThnA3) and a oxygenase (ThnA1/ThnA2), forming a NAD(P)H–ThnA4–ThnA3–ThnA1/ThnA2 electron transport chain. ThnA3 has also a regulatory function since it prevents expression of tetralin degradation genes (thn) in the presence of non-metabolizable substrates of the catabolic pathway. This role is of physiological relevance since avoids gratuitous and wasteful production of catabolic enzymes. Our hypothesis for thn regulation implies that ThnA3 exerts its action by diverting electrons towards the regulator ThnY, an iron-sulfur flavoprotein that together with the transcriptional activator ThnR is necessary for thn gene expression. Here we analyze electron transfer among ThnA4, ThnA3 and ThnY by using stopped-flow spectrophotometry and determination of midpoint reduction potentials. Our results indicate that when accumulated in its reduced form ThnA3 is able to fully reduce ThnY. In addition, we have reproduced in vitro the regulatory circuit in the proposed physiological direction, NAD(P)H–ThnA4–ThnA3–ThnY. ThnA3 represents an unprecedented way of communication between a catabolic pathway and its regulatory system to prevent gratuitous induction. PMID:27030382

  7. Transgenic Leucaena leucocephala expressing the Rhizobium gene pydA encoding a meta-cleavage dioxygenase shows reduced mimosine content.

    Science.gov (United States)

    Jube, Sandro L R; Borthakur, Dulal

    2010-04-01

    The use of the tree-legume Leucaena leucocephala (leucaena), which contains high levels of proteins in its foliage, is limited due to the presence of the toxic free amino acid mimosine. The goal of this research was to develop transgenic leucaena with reduced mimosine content. Two genes, pydA and pydB, encoding a meta-cleavage dioxygenase (EC 1.13.11.2) and a pyruvate hydrolase (EC 3.7.1.6), respectively, from the mimosine-degrading leucaena symbiont Rhizobium sp. strain TAL1145, were used to transform leucaena. These bacterial genes were sequence-optimized for expression in leucaena and cloned into the plant binary vector pCAMBIA3201 for Agrobacterium tumefaciens-mediated transformation. Using immature zygotic embryos as the start explant material, six pydA and three pydB transgenic lines were developed. The presence and expression of the bacterial genes in the transgenic lines were verified by PCR, reverse transcriptase PCR, and Southern analyses. HPLC analyses of the transgenic plants determined that the mimosine contents of the pydA-expressing lines were reduced up to 22.5% in comparison to the wild-type. No significant reduction in mimosine content was observed in the pydB-expressing lines. This is the first example of using a gene from a bacterial symbiont to reduce the toxicity of a tree-legume.

  8. Differential expression of biphenyl synthase gene family members in fire-blight-infected apple 'Holsteiner Cox'.

    Science.gov (United States)

    Chizzali, Cornelia; Gaid, Mariam M; Belkheir, Asma K; Hänsch, Robert; Richter, Klaus; Flachowsky, Henryk; Peil, Andreas; Hanke, Magda-Viola; Liu, Benye; Beerhues, Ludger

    2012-02-01

    Fire blight, caused by the bacterium Erwinia amylovora, is a devastating disease of apple (Malus × domestica). The phytoalexins of apple are biphenyls and dibenzofurans, whose carbon skeleton is formed by biphenyl synthase (BIS), a type III polyketide synthase. In the recently published genome sequence of apple 'Golden Delicious', nine BIS genes and four BIS gene fragments were detected. The nine genes fall into four subfamilies, referred to as MdBIS1 to MdBIS4. In a phylogenetic tree, the BIS amino acid sequences from apple and Sorbus aucuparia formed an individual cluster within the clade of the functionally diverse type III polyketide synthases. cDNAs encoding MdBIS1 to MdBIS4 were cloned from fire-blight-infected shoots of apple 'Holsteiner Cox,' heterologously expressed in Escherichia coli, and functionally analyzed. Benzoyl-coenzyme A and salicoyl-coenzyme A were the preferred starter substrates. In response to inoculation with E. amylovora, the BIS3 gene was expressed in stems of cv Holsteiner Cox, with highest transcript levels in the transition zone between necrotic and healthy tissues. The transition zone was the accumulation site of biphenyl and dibenzofuran phytoalexins. Leaves contained transcripts for BIS2 but failed to form immunodetectable amounts of BIS protein. In cell cultures of apple 'Cox Orange,' expression of the BIS1 to BIS3 genes was observed after the addition of an autoclaved E. amylovora suspension. Using immunofluorescence localization under a confocal laser-scanning microscope, the BIS3 protein in the transition zone of stems was detected in the parenchyma of the bark. Dot-shaped immunofluorescence was confined to the junctions between neighboring cortical parenchyma cells.

  9. 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.

  10. Identification and characterization of genes encoding polycyclic aromatic hydrocarbon dioxygenase and polycyclic aromatic hydrocarbon dihydrodiol dehydrogenase in Pseudomonas putida OUS82.

    OpenAIRE

    Takizawa, N; Kaida, N; Torigoe, S; Moritani,T.; Sawada, T.; Satoh, S.; Kiyohara, H

    1994-01-01

    Naphthalene and phenanthrene are transformed by enzymes encoded by the pah gene cluster of Pseudomonas putida OUS82. The pahA and pahB genes, which encode the first and second enzymes, dioxygenase and cis-dihydrodiol dehydrogenase, respectively, were identified and sequenced. The DNA sequences showed that pahA and pahB were clustered and that pahA consisted of four cistrons, pahAa, pahAb, pahAc, and pahAd, which encode ferredoxin reductase, ferredoxin, and two subunits of the iron-sulfur prot...

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

    NARCIS (Netherlands)

    Wadman, Mayken W; de Vries, Ronald P; Kalkhove, Stefanie I C; Veldink, Gerrit A; Vliegenthart, Johannes F G

    2009-01-01

    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 dio

  12. Effects of polycyclic aromatic hydrocarbons on microbial community structure and PAH ring hydroxylating dioxygenase gene abundance in soil.

    Science.gov (United States)

    Sawulski, Przemyslaw; Clipson, Nicholas; Doyle, Evelyn

    2014-11-01

    Development of successful bioremediation strategies for environments contaminated with recalcitrant pollutants requires in-depth knowledge of the microorganisms and microbial processes involved in degradation. The response of soil microbial communities to three polycyclic aromatic hydrocarbons, phenanthrene (3-ring), fluoranthene (4-ring) and benzo(a)pyrene (5-ring), was examined. Profiles of bacterial, archaeal and fungal communities were generated using molecular fingerprinting techniques (TRFLP, ARISA) and multivariate statistical tools were employed to interpret the effect of PAHs on community dynamics and composition. The extent and rate of PAH removal was directly related to the chemical structure, with the 5-ring PAH benzo(a)pyrene degraded more slowly than phenathrene or fluoranthene. Bacterial, archaeal and fungal communities were all significantly affected by PAH amendment, time and their interaction. Based on analysis of clone libraries, Actinobacteria appeared to dominate in fluoranthene amended soil, although they also represented a significant portion of the diversity in phenanthrene amended and unamended soils. In addition there appeared to be more γ-Proteobacteria and less Bacteroidetes in soil amended with either PAH compared to the control. The soil bacterial community clearly possessed the potential to degrade PAHs as evidenced by the abundance of PAH ring hydroxylating (PAH-RHDα) genes from both gram negative (GN) and gram positive (GP) bacteria in PAH-amended and control soils. Although the dioxygenase gene from GP bacteria was less abundant in soil than the gene associated with GN bacteria, significant (p PAH-RHDα gene were observed during phenanthrene and fluoranthene degradation, whereas there was no significant difference in the abundance of the GN PAH-RHDα gene during the course of the experiment. Few studies to-date have examined the effect of pollutants on more than one microbial community in soil. The current study provides

  13. Patchwork assembly of nag-like nitroarene dioxygenase genes and the 3-chlorocatechol degradation cluster for evolution of the 2-chloronitrobenzene catabolism pathway in Pseudomonas stutzeri ZWLR2-1.

    Science.gov (United States)

    Liu, Hong; Wang, Shu-Jun; Zhang, Jun-Jie; Dai, Hui; Tang, Huiru; Zhou, Ning-Yi

    2011-07-01

    Pseudomonas stutzeri ZWLR2-1 utilizes 2-chloronitrobenzene (2CNB) as a sole source of carbon, nitrogen, and energy. To identify genes involved in this pathway, a 16.2-kb DNA fragment containing putative 2CNB dioxygenase genes was cloned and sequenced. Of the products from the 19 open reading frames that resulted from this fragment, CnbAc and CnbAd exhibited striking identities to the respective α and β subunits of the Nag-like ring-hydroxylating dioxygenases involved in the metabolism of nitrotoluene, nitrobenzene, and naphthalene. The encoding genes were also flanked by two copies of insertion sequence IS6100. CnbAa and CnbAb are similar to the ferredoxin reductase and ferredoxin for anthranilate 1,2-dioxygenase from Burkholderia cepacia DBO1. Escherichia coli cells expressing cnbAaAbAcAd converted 2CNB to 3-chlorocatechol with concomitant nitrite release. Cell extracts of E. coli/pCNBC exhibited chlorocatechol 1,2-dioxygenase activity. The cnbCDEF gene cluster, homologous to a 3-chlorocatechol degradation cluster in Sphingomonas sp. strain TFD44, probably contains all of the genes necessary for the conversion of 3-chlorocatechol to 3-oxoadipate. The patchwork-like structure of this catabolic cluster suggests that the cnb cluster for 2CNB degradation evolved by recruiting two catabolic clusters encoding a nitroarene dioxygenase and a chlorocatechol degradation pathway. This provides another example to help elucidate the bacterial evolution of catabolic pathways in response to xenobiotic chemicals.

  14. OXIDATION OF BIPHENYL BY A MULTICOMPONENT ENZYME SYSTEM FROM PSEUDOMONAS SP. STRAIN LB400

    Science.gov (United States)

    Pseudomonas sp. strain LB400 grows on biphenyl as the sole carbon and energy source. This organism also cooxidizes several chlorinated biphenyl congeners. Biphenyl dioxygenase activity in cell extract required addition of NAD(P)H as an electron donor for the conversion of bipheny...

  15. Abundance of Dioxygenase Genes Similar to Ralstonia sp. Strain U2 nagAc Is Correlated with Naphthalene Concentrations in Coal Tar-Contaminated Freshwater Sediments

    Science.gov (United States)

    Dionisi, Hebe M.; Chewning, Christopher S.; Morgan, Katherine H.; Menn, Fu-Min; Easter, James P.; Sayler, Gary S.

    2004-01-01

    We designed a real-time PCR assay able to recognize dioxygenase large-subunit gene sequences with more than 90% similarity to the Ralstonia sp. strain U2 nagAc gene (nagAc-like gene sequences) in order to study the importance of organisms carrying these genes in the biodegradation of naphthalene. Sequencing of PCR products indicated that this real-time PCR assay was specific and able to detect a variety of nagAc-like gene sequences. One to 100 ng of contaminated-sediment total DNA in 25-μl reaction mixtures produced an amplification efficiency of 0.97 without evident PCR inhibition. The assay was applied to surficial freshwater sediment samples obtained in or in close proximity to a coal tar-contaminated Superfund site. Naphthalene concentrations in the analyzed samples varied between 0.18 and 106 mg/kg of dry weight sediment. The assay for nagAc-like sequences indicated the presence of (4.1 ± 0.7) × 103 to (2.9 ± 0.3) × 105 copies of nagAc-like dioxygenase genes per μg of DNA extracted from sediment samples. These values corresponded to (1.2 ± 0.6) × 105 to (5.4 ± 0.4) × 107 copies of this target per g of dry weight sediment when losses of DNA during extraction were taken into account. There was a positive correlation between naphthalene concentrations and nagAc-like gene copies per microgram of DNA (r = 0.89) and per gram of dry weight sediment (r = 0.77). These results provide evidence of the ecological significance of organisms carrying nagAc-like genes in the biodegradation of naphthalene. PMID:15240274

  16. Cysteine dioxygenase and cysteine sulfinate decarboxylase genes of the deep-sea mussel Bathymodiolus septemdierum: possible involvement in hypotaurine synthesis and adaptation to hydrogen sulfide.

    Science.gov (United States)

    Nagasaki, Toshihiro; Hongo, Yuki; Koito, Tomoko; Nakamura-Kusakabe, Ikumi; Shimamura, Shigeru; Takaki, Yoshihiro; Yoshida, Takao; Maruyama, Tadashi; Inoue, Koji

    2015-03-01

    It has been suggested that invertebrates inhabiting deep-sea hydrothermal vent areas use the sulfinic acid hypotaurine, a precursor of taurine, to protect against the toxicity of hydrogen sulfide contained in the seawater from the vent. In this protective system, hypotaurine is accumulated in the gill, the primary site of sulfide exposure. However, the pathway for hypotaurine synthesis in mollusks has not been identified. In this study, we screened for the mRNAs of enzymes involved in hypotaurine synthesis in the deep-sea mussel Bathymodiolus septemdierum and cloned cDNAs encoding cysteine dioxygenase and cysteine sulfinate decarboxylase. As mRNAs encoding cysteamine dioxygenase and cysteine lyase were not detected, the cysteine sulfinate pathway is suggested to be the major pathway of hypotaurine and taurine synthesis. The two genes were found to be expressed in all the tissues examined, but the gill exhibited the highest expression. The mRNA level in the gill was not significantly changed by exposure to sulfides or thiosulfate. These results suggests that the gill of B. septemdierum maintains high levels of expression of the two genes regardless of ambient sulfide level and accumulates hypotaurine continuously to protect against sudden exposure to high level of sulfide.

  17. Comparative quantitative prevalence of mycobacteria and functionally abundant nidA, nahAc, and nagAc Dioxygenase genes in coal tar contaminated sediments

    Energy Technology Data Exchange (ETDEWEB)

    Jennifer M. DeBruyn; Christopher S. Chewning; Gary S. Sayler [University of Tennessee, Knoxville, TN (United States). Department of Ecology and Evolutionary Biology

    2007-08-01

    The Chattanooga Creek Superfund site is heavily contaminated with metals, pesticides, and coal tar with sediments exhibiting high concentrations of polycyclic aromatic hydrocarbons (PAHs). High molecular weight PAHs are of concern because of their toxicity and recalcitrance in the environment; as such, there is great interest in microbes, such as fast-growing Mycobacterium spp., capable of degradation of these compounds. Real-time quantitative PCR assays were developed targeting multiple dioxygenase genes to assess the ecology and functional diversity of PAH-degrading communities. These assays target the Mycobacterium nidA, {beta}-proteobacteria nagAc, and {gamma}-proteobacteria nahAc with the specific goal of testing the hypothesis that Mycobacteria catabolic genes are enriched and may be functionally associated with high molecular weight PAH biodegradation in Chattanooga Creek. Dioxygenase gene abundances were quantitatively compared to naphthalene and pyrene mineralization, and temporal and spatial PAH concentrations. nidA abundances ranged from 5.69 x 10{sup 4} to 4.92 x 10{sup 6} copies per gram sediment; nagAc from 2.42 x 10{sup 3} to 1.21 x 10{sup 7}, and nahAc from below detection to 4.01 x 10{sup 6} copies per gram sediment. There was a significantly greater abundance of nidA and nagAc at sites with the greatest concentrations of PAHs. In addition, nidA and nagAc were significantly positively correlated, indicating a coexistence of organisms carrying these genes. A positive relationship was also observed between nidA and nagAc and pyrene mineralization indicating that these genes serve as biomarkers for pyrene degradation. A 16S rDNA clone library of fast-growing Mycobacteria indicated that the population is very diverse and likely plays an important role in attenuation of high molecular weight PAHs from Chattanooga Creek. 35 refs., 5 figs., 1 tab.

  18. Expression of Biphenyl Synthase Genes and Formation of Phytoalexin Compounds in Three Fire Blight-Infected Pyrus communis Cultivars.

    Directory of Open Access Journals (Sweden)

    Cornelia Chizzali

    Full Text Available Pear (Pyrus communis is an economically important fruit crop. Drops in yield and even losses of whole plantations are caused by diseases, most importantly fire blight which is triggered by the bacterial pathogen Erwinia amylovora. In response to the infection, biphenyls and dibenzofurans are formed as phytoalexins, biosynthesis of which is initiated by biphenyl synthase (BIS. Two PcBIS transcripts were cloned from fire blight-infected leaves and the encoded enzymes were characterized regarding substrate specificities and kinetic parameters. Expression of PcBIS1 and PcBIS2 was studied in three pear cultivars after inoculation with E. amylovora. Both PcBIS1 and PcBIS2 were expressed in 'Harrow Sweet', while only PcBIS2 transcripts were detected in 'Alexander Lucas' and 'Conference'. Expression of the PcBIS genes was observed in both leaves and the transition zone of the stem; however, biphenyls and dibenzofurans were only detected in stems. The maximum phytoalexin level (~110 μg/g dry weight was observed in the transition zone of 'Harrow Sweet', whereas the concentrations were ten times lower in 'Conference' and not even detectable in 'Alexander Lucas'. In 'Harrow Sweet', the accumulation of the maximum phytoalexin level correlated with the halt of migration of the transition zone, whereby the residual part of the shoot survived. In contrast, the transition zones of 'Alexander Lucas' and 'Conference' advanced down to the rootstock, resulting in necrosis of the entire shoots.

  19. Expression of Biphenyl Synthase Genes and Formation of Phytoalexin Compounds in Three Fire Blight-Infected Pyrus communis Cultivars.

    Science.gov (United States)

    Chizzali, Cornelia; Swiddan, Asya K; Abdelaziz, Sahar; Gaid, Mariam; Richter, Klaus; Fischer, Thilo C; Liu, Benye; Beerhues, Ludger

    2016-01-01

    Pear (Pyrus communis) is an economically important fruit crop. Drops in yield and even losses of whole plantations are caused by diseases, most importantly fire blight which is triggered by the bacterial pathogen Erwinia amylovora. In response to the infection, biphenyls and dibenzofurans are formed as phytoalexins, biosynthesis of which is initiated by biphenyl synthase (BIS). Two PcBIS transcripts were cloned from fire blight-infected leaves and the encoded enzymes were characterized regarding substrate specificities and kinetic parameters. Expression of PcBIS1 and PcBIS2 was studied in three pear cultivars after inoculation with E. amylovora. Both PcBIS1 and PcBIS2 were expressed in 'Harrow Sweet', while only PcBIS2 transcripts were detected in 'Alexander Lucas' and 'Conference'. Expression of the PcBIS genes was observed in both leaves and the transition zone of the stem; however, biphenyls and dibenzofurans were only detected in stems. The maximum phytoalexin level (~110 μg/g dry weight) was observed in the transition zone of 'Harrow Sweet', whereas the concentrations were ten times lower in 'Conference' and not even detectable in 'Alexander Lucas'. In 'Harrow Sweet', the accumulation of the maximum phytoalexin level correlated with the halt of migration of the transition zone, whereby the residual part of the shoot survived. In contrast, the transition zones of 'Alexander Lucas' and 'Conference' advanced down to the rootstock, resulting in necrosis of the entire shoots.

  20. Genomic analysis and gene structure of the plant carotenoid dioxygenase 4 family: a deeper study in Crocus sativus and its allies.

    Science.gov (United States)

    Ahrazem, Oussama; Trapero, Almudena; Gómez, M Dolores; Rubio-Moraga, Angela; Gómez-Gómez, Lourdes

    2010-10-01

    The plastoglobule-targeted enzyme carotenoid cleavage dioxygenase (CCD4) mediates the formation of volatile C13 ketones, such as β-ionone, by cleaving the C9-C10 and C9'-C10' double bonds of cyclic carotenoids. Here, we report the isolation and analysis of CCD4 genomic DNA regions in Crocus sativus. Different CCD4 alleles have been identified: CsCCD4a which is found with and without an intron and CsCCD4b that showed the presence of a unique intron. The presence of different CCD4 alleles was also observed in other Crocus species. Furthermore, comparison of the locations of CCD4 introns within the coding region with CCD4 genes from other plant species suggests that independent gain/losses have occurred. The comparison of the promoter region of CsCCD4a and CsCCD4b with available CCD4 gene promoters from other plant species highlighted the conservation of cis-elements involved in light response, heat stress, as well as the absence and unique presence of cis-elements involved in circadian regulation and low temperature responses, respectively. Functional characterization of the Crocus sativus CCD4a promoter using Arabidopsis plants stably transformed with a DNA fragment of 1400 base pairs (P-CsCCD4a) fused to the β-glucuronidase (GUS) reporter gene showed that this sequence was sufficient to drive GUS expression in the flower, in particular high levels were detected in pollen.

  1. St. John's Wort increases brain serotonin synthesis by inhibiting hepatic tryptophan 2, 3 dioxygenase activity and its gene expression in stressed rats.

    Science.gov (United States)

    Bano, Samina; Ara, Iffat; Saboohi, Kausar; Moattar, Tariq; Chaoudhry, Bushra

    2014-09-01

    We aimed to investigate the effects of herbal St. John's Wort (SJW) on transcriptional regulation of hepatic tryptophan 2, 3 - dioxygenase (TDO) enzyme activity and brain regional serotonin (5-HT) levels in rats exposed to forced swim test (FST). TDO mRNA expression was quantified using real-time reverse transcription polymerase chain (RT-PCR) reaction and brain regional indoleamines were determined by high performance liquid chromatography coupled to fluorescence detector. Behavioral analysis shows significant reduction in immobility time in SJW (500mg/kg/ml) administered rats. It was found that pretreatment of SJW to rats did not prevent stress-induced elevation in plasma corticosterone levels however it increases serotonin synthesis by virtue of inhibiting hepatic TDO enzyme activity and its gene expression, ascertaining the notion that there exists an inverse relationship between hepatic TDO enzyme activity and brain 5-HT. The drug also decreases serotonin turnover in all the brain areas (hypothalamus, hippocampus amygdala) in stressed rats endorsing its monoamine oxidase inhibition property. Inhibition of TDO enzyme activity and its gene expression by the drug provides new insights for the development of therapeutic interventions for stress related mental illnesses.

  2. Polychlorinated Biphenyls

    Science.gov (United States)

    Peakall, David B.; Lincer, Jeffrey L.

    1970-01-01

    Describes structure, use, analysis, and toxicological properties of polychlorinated biphenyls. Provides data on occurrence and biological magnification in ecosystems. Significance, and synergistic relationships with DDT summarized. (AL)

  3. 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.

  4. 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

  5. Developmental and stress regulation of gene expression for a 9-cis-epoxycarotenoid dioxygenase, CstNCED, isolated from Crocus sativus stigmas.

    Science.gov (United States)

    Ahrazem, Oussama; Rubio-Moraga, Angela; Trapero, Almudena; Gómez-Gómez, Lourdes

    2012-01-01

    Oxidative cleavage of cis-epoxycarotenoids by 9-cis-epoxycarotenoid dioxygenase (NCED) is the critical step in the regulation of abscisic acid (ABA) synthesis in higher plants. ABA has been associated with dormancy and flower senescence, while also regulating plant adaptive responses to various environmental stresses. An NCED gene, CstNCED, was cloned from Crocus sativus stigmas. The deduced amino acid sequence of the CstNCED protein shared high identity with other monocot NCEDs, and was closely related to the liliopsida enzymes. At the N-terminus of CstNCED a chloroplast transit peptide sequence is located. However, its expression in chloroplast-free tissues suggested localization in other plastid types. The relationship between expression of CstNCED and the endogenous ABA level was investigated in the stigma and corms, where it was developmentally regulated. The senescence of the unpollinated stigma is preceded by an increase in ABA levels and CstNCED expression. In corms, a correlation was observed between CstNCED expression and dormancy. Furthermore, CstNCED expression was correlated with the presence of zeaxanthin in the dormant corms. When detached C. sativus leaves and stigmas were water and salt stressed, increases in CstNCED mRNA were observed. The results provided evidence of the involvement of CstNCED in the regulation of ABA-associated processes such as flower senescence and corm dormancy in monocotyledonous saffron.

  6. Prognostic significance of Tet methylcytosine dioxygenase 2 (TET2) gene mutations in adult patients with acute myeloid leukemia: a meta-analysis.

    Science.gov (United States)

    Liu, Wen-Jian; Tan, Xiao-Hong; Luo, Xiu-Ping; Guo, Bao-Ping; Wei, Zhou-Ji; Ke, Qing; He, Sha; Cen, Hong

    2014-12-01

    Tet methylcytosine dioxygenase 2 (TET2) gene mutations have recently been recognized in acute myeloid leukemia (AML). We performed a meta-analysis to evaluate the controversial prognostic significance of TET2 mutations in AML. Eight studies, covering 2552 patients with AML, were included in this analysis. Pooled hazard ratios (HRs) indicated that TET2 mutations had a poor prognostic impact on the survival of patients with AML. The combined HR for overall survival (OS) was 1.53 and the summary HR for event-free survival (EFS) was 1.64. Additionally, TET2 mutations appeared to be an adverse prognostic indicator in both patients with cytogenetically normal (CN)-AML (HR for OS: 1.43 and HR for EFS: 1.76) and subgroups of patients with favorable-risk genotypes (HR for EFS: 2.35) and intermediate-I-risk genotypes (HR for EFS: 1.57). These findings indicate that TET2 mutations have an adverse impact on prognosis and may help to justify risk-adapted therapeutic strategies for patients with AML.

  7. Molecular characterization of the gallate dioxygenase from Pseudomonas putida KT2440. The prototype of a new subgroup of extradiol dioxygenases.

    Science.gov (United States)

    Nogales, Juan; Canales, Angeles; Jiménez-Barbero, Jesús; García, José Luis; Díaz, Eduardo

    2005-10-21

    In this work we have characterized the galA gene product from Pseudomonas putida KT2440, a ring-cleavage dioxygenase that acts specifically on gallate to produce 4-oxalomesaconate. The protein is a trimer composed by three identical subunits of 47.6 kDa (419 amino acids) that uses Fe2+ as the main cofactor. The gallate dioxygenase showed maximum activity at pH 7.0, and the Km and Vmax values for gallate were 144 microM and 53.2 micromol/min/mg of protein, respectively. A phylogenetic study suggests that the gallate dioxygenase from P. putida KT2440 is the prototype of a new subgroup of type II extradiol dioxygenases that share a common ancestor with protocatechuate 4,5-dioxygenases and whose two-domain architecture might have evolved from the fusion of the large and small subunits of the latter. A three-dimensional model for the N-terminal domain (residues 1-281) and C-terminal domain (residues 294-420) of the gallate dioxygenase from P. putida KT2440 was generated by comparison with the crystal structures of the large (LigB) and small (LigA) subunits of the protocatechuate 4,5-dioxygenase from Sphingomonas paucimobilis SYK-6. The expression of the galA gene was specifically induced when P. putida KT2440 cells grew in the presence of gallate. A P. putida KT2440 galA mutant strain was unable to use gallate as the sole carbon source and it did not show gallate dioxygenase activity, suggesting that the GalA protein is the only dioxygenase involved in gallate cleavage in this bacterium. This work points to the existence of a new pathway that is devoted to the catabolism of gallic acid and that remained unknown in the paradigmatic P. putida KT2440 strain.

  8. Expression of Biphenyl Synthase Genes and Formation of Phytoalexin Compounds in Three Fire Blight-Infected Pyrus communis Cultivars

    Science.gov (United States)

    Chizzali, Cornelia; Swiddan, Asya K.; Abdelaziz, Sahar; Gaid, Mariam; Richter, Klaus; Fischer, Thilo C.; Liu, Benye; Beerhues, Ludger

    2016-01-01

    Pear (Pyrus communis) is an economically important fruit crop. Drops in yield and even losses of whole plantations are caused by diseases, most importantly fire blight which is triggered by the bacterial pathogen Erwinia amylovora. In response to the infection, biphenyls and dibenzofurans are formed as phytoalexins, biosynthesis of which is initiated by biphenyl synthase (BIS). Two PcBIS transcripts were cloned from fire blight-infected leaves and the encoded enzymes were characterized regarding substrate specificities and kinetic parameters. Expression of PcBIS1 and PcBIS2 was studied in three pear cultivars after inoculation with E. amylovora. Both PcBIS1 and PcBIS2 were expressed in ‘Harrow Sweet’, while only PcBIS2 transcripts were detected in ‘Alexander Lucas’ and ‘Conference’. Expression of the PcBIS genes was observed in both leaves and the transition zone of the stem; however, biphenyls and dibenzofurans were only detected in stems. The maximum phytoalexin level (~110 μg/g dry weight) was observed in the transition zone of ‘Harrow Sweet’, whereas the concentrations were ten times lower in ‘Conference’ and not even detectable in ‘Alexander Lucas’. In ‘Harrow Sweet’, the accumulation of the maximum phytoalexin level correlated with the halt of migration of the transition zone, whereby the residual part of the shoot survived. In contrast, the transition zones of ‘Alexander Lucas’ and ‘Conference’ advanced down to the rootstock, resulting in necrosis of the entire shoots. PMID:27410389

  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. New target carotenoids for CCD4 enzymes are revealed with the characterization of a novel stress-induced carotenoid cleavage dioxygenase gene from Crocus sativus.

    Science.gov (United States)

    Rubio-Moraga, Angela; Rambla, José Luis; Fernández-de-Carmen, Asun; Trapero-Mozos, Almudena; Ahrazem, Oussama; Orzáez, Diego; Granell, Antonio; Gómez-Gómez, Lourdes

    2014-11-01

    Apocarotenoid compounds play diverse communication functions in plants, some of them being as hormones, pigments and volatiles. Apocarotenoids are the result of enzymatic cleavage of carotenoids catalyzed by carotenoid cleavage dioxygenase (CCD). The CCD4 family is the largest family of plant CCDs, only present in flowering plants, suggesting a functional diversification associated to the adaptation for specific physiological capacities unique to them. In saffron, two CCD4 genes have been previously isolated from the stigma tissue and related with the generation of specific volatiles involved in the attraction of pollinators. The aim of this study was to identify additional CCD4 members associated with the generation of other carotenoid-derived volatiles during the development of the stigma. The expression of CsCCD4c appears to be restricted to the stigma tissue in saffron and other Crocus species and was correlated with the generation of megastigma-4,6,8-triene. Further, CsCCD4c was up-regulated by wounding, heat, and osmotic stress, suggesting an involvement of its apocarotenoid products in the adaptation of saffron to environmental stresses. The enzymatic activity of CsCCD4c was determined in vivo in Escherichia coli and subsequently in Nicotiana benthamiana by analyzing carotenoids by HPLC-DAD and the volatile products by GC/MS. β-Carotene was shown to be the preferred substrate, being cleaved at the 9,10 (9',10') bonds and generating β-ionone, although β-cyclocitral resulting from a 7,8 (7',8') cleavage activity was also detected at lower levels. Lutein, neoxanthin and violaxanthin levels in Nicotiana leaves were markedly reduced when CsCCD4c is over expressed, suggesting that CsCCD4c recognizes these carotenoids as substrates.

  11. Expression of Biphenyl Synthase Genes and Formation of Phytoalexin Compounds in Three Fire Blight-Infected Pyrus communis Cultivars

    OpenAIRE

    Cornelia Chizzali; Swiddan, Asya K.; Sahar Abdelaziz; Mariam Gaid; Klaus Richter; Fischer, Thilo C.; Benye Liu; Ludger Beerhues

    2016-01-01

    Pear (Pyrus communis) is an economically important fruit crop. Drops in yield and even losses of whole plantations are caused by diseases, most importantly fire blight which is triggered by the bacterial pathogen Erwinia amylovora. In response to the infection, biphenyls and dibenzofurans are formed as phytoalexins, biosynthesis of which is initiated by biphenyl synthase (BIS). Two PcBIS transcripts were cloned from fire blight-infected leaves and the encoded enzymes were characterized regard...

  12. Crystal structure of the terminal oxygenase component of cumene dioxygenase from Pseudomonas fluorescens IP01.

    Science.gov (United States)

    Dong, Xuesong; Fushinobu, Shinya; Fukuda, Eriko; Terada, Tohru; Nakamura, Shugo; Shimizu, Kentaro; Nojiri, Hideaki; Omori, Toshio; Shoun, Hirofumi; Wakagi, Takayoshi

    2005-04-01

    The crystal structure of the terminal component of the cumene dioxygenase multicomponent enzyme system of Pseudomonas fluorescens IP01 (CumDO) was determined at a resolution of 2.2 A by means of molecular replacement by using the crystal structure of the terminal oxygenase component of naphthalene dioxygenase from Pseudomonas sp. strain NCIB 9816-4 (NphDO). The ligation of the two catalytic centers of CumDO (i.e., the nonheme iron and Rieske [2Fe-2S] centers) and the bridging between them in neighboring catalytic subunits by hydrogen bonds through a single amino acid residue, Asp231, are similar to those of NphDO. An unidentified external ligand, possibly dioxygen, was bound at the active site nonheme iron. The entrance to the active site of CumDO is different from the entrance to the active site of NphDO, as the two loops forming the lid exhibit great deviation. On the basis of the complex structure of NphDO, a biphenyl substrate was modeled in the substrate-binding pocket of CumDO. The residues surrounding the modeled biphenyl molecule include residues that have already been shown to be important for its substrate specificity by a number of engineering studies of biphenyl dioxygenases.

  13. Differential Expression of Biphenyl Synthase Gene Family Members in Fire-Blight-Infected Apple ‘Holsteiner Cox’ 1[W][OA

    Science.gov (United States)

    Chizzali, Cornelia; Gaid, Mariam M.; Belkheir, Asma K.; Hänsch, Robert; Richter, Klaus; Flachowsky, Henryk; Peil, Andreas; Hanke, Magda-Viola; Liu, Benye; Beerhues, Ludger

    2012-01-01

    Fire blight, caused by the bacterium Erwinia amylovora, is a devastating disease of apple (Malus × domestica). The phytoalexins of apple are biphenyls and dibenzofurans, whose carbon skeleton is formed by biphenyl synthase (BIS), a type III polyketide synthase. In the recently published genome sequence of apple ‘Golden Delicious’, nine BIS genes and four BIS gene fragments were detected. The nine genes fall into four subfamilies, referred to as MdBIS1 to MdBIS4. In a phylogenetic tree, the BIS amino acid sequences from apple and Sorbus aucuparia formed an individual cluster within the clade of the functionally diverse type III polyketide synthases. cDNAs encoding MdBIS1 to MdBIS4 were cloned from fire-blight-infected shoots of apple ‘Holsteiner Cox,’ heterologously expressed in Escherichia coli, and functionally analyzed. Benzoyl-coenzyme A and salicoyl-coenzyme A were the preferred starter substrates. In response to inoculation with E. amylovora, the BIS3 gene was expressed in stems of cv Holsteiner Cox, with highest transcript levels in the transition zone between necrotic and healthy tissues. The transition zone was the accumulation site of biphenyl and dibenzofuran phytoalexins. Leaves contained transcripts for BIS2 but failed to form immunodetectable amounts of BIS protein. In cell cultures of apple ‘Cox Orange,’ expression of the BIS1 to BIS3 genes was observed after the addition of an autoclaved E. amylovora suspension. Using immunofluorescence localization under a confocal laser-scanning microscope, the BIS3 protein in the transition zone of stems was detected in the parenchyma of the bark. Dot-shaped immunofluorescence was confined to the junctions between neighboring cortical parenchyma cells. PMID:22158676

  14. Bioaugmentation of a historically contaminated soil by polychlorinated biphenyls with Lentinus tigrinus

    Directory of Open Access Journals (Sweden)

    Federici Ermanno

    2012-03-01

    Full Text Available Abstract Background Several species belonging to the ecological group of white-rot basidiomycetes are able to bring about the remediation of matrices contaminated by a large variety of anthropic organic pollutants. Among them, polychlorobiphenyls (PCBs are characterized by a high recalcitrance due to both their low bioavailability and the inability of natural microbial communities to degrade them at significant rates and extents. Objective of this study was to assess the impact of a maize stalk-immobilized Lentinus tigrinus CBS 577.79 inoculant combined with soybean oil (SO, as a possible PCB-mobilizing agent, on the bioremediation and resident microbiota of an actual Aroclor 1260 historically contaminated soil under unsaturated solid-phase conditions. Results Best overall PCB depletions (33.6 ± 0.3% and dechlorination (23.2 ± 1.3% were found after 60 d incubation in the absence of SO where, however, the fungus appeared to exert adverse effects on both the growth of biphenyl- and chlorobenzoate-degrading bacteria and the abundance of genes coding for both biphenyl dioxygenase (bph and catechol-2,3-dioxygenase. A significant (P bph. Conclusions The PCB depletion extents obtained in the presence of L. tigrinus are by far higher than those reported in other remediation studies conducted under unsaturated solid phase conditions on actual site soils historically contaminated by Aroclor 1260. These results suggest that the bioaugmentation strategy with the maize stalk-immobilized mycelium of this species might be promising in the reclamation of PCB-contaminated soils. The addition of SO to matrices contaminated by technical PCB mixtures, such as Aroclor 1242 and Delor 103 and characterized by a large preponderance of low chlorinated congeners, might not be advisable.

  15. Enhanced Polychlorinated Biphenyl Removal in a Switchgrass Rhizosphere by Bioaugmentation with Burkholderia xenovorans LB400.

    Science.gov (United States)

    Liang, Yi; Meggo, Richard; Hu, Dingfei; Schnoor, Jerald L; Mattes, Timothy E

    2014-10-01

    Phytoremediation makes use of plants and associated microorganisms to clean up soils and sediments contaminated with inorganic and organic pollutants. In this study, switchgrass (Panicum virgatum) was used to test for its efficiency in improving the removal of three specific polychlorinated biphenyl (PCB) congeners (PCB 52, 77 and 153) in soil microcosms. The congeners were chosen for their ubiquity, toxicity, and recalcitrance. After 24 weeks of incubation, loss of 39.9 ± 0.41% of total PCB molar mass was observed in switchgrass treated soil, significantly higher than in unplanted soil (29.5 ± 3.4%) (p<0.05). The improved PCB removal in switchgrass treated soils could be explained by phytoextraction processes and enhanced microbial activity in the rhizosphere. Bioaugmentation with Burkholderia xenovorans LB400 was performed to further enhance aerobic PCB degradation. The presence of LB400 was associated with improved degradation of PCB 52, but not PCB 77 or PCB 153. Increased abundances of bphA (a functional gene that codes for a subunit of PCB-degrading biphenyl dioxygenase in bacteria) and its transcript were observed after bioaugmentation. The highest total PCB removal was observed in switchgrass treated soil with LB400 bioaugmentation (47.3 ± 1.22 %), and the presence of switchgrass facilitated LB400 survival in the soil. Overall, our results suggest the combined use of phytoremediation and bioaugmentation could be an efficient and sustainable strategy to eliminate recalcitrant PCB congeners and remediate PCB-contaminated soil.

  16. A gene expression study of the activities of aromatic ring-cleavage dioxygenases in Mycobacterium gilvum PYR-GCK to changes in salinity and pH during pyrene degradation.

    Directory of Open Access Journals (Sweden)

    Abimbola Comfort Badejo

    Full Text Available Polycyclic aromatic hydrocarbons (PAHs are toxic pollutants found in the environment which can be removed through the use of physical and biological agents. The rate of PAH biodegradation is affected by environmental conditions of pH, salinity and temperature. Adaptation of the pyrene degrading bacteria, Mycobacterium gilvum PYR-GCK, to fluctuating environmental conditions during pyrene biodegrading activity was studied using the quantitative real time - Polymerase Chain Reaction (qRT-PCR technique. Four aromatic ring-cleavage dioxygenase genes: phdF, phdI, pcaG and pcaH; critical to pyrene biodegradation, were studied in pH states of 5.5, 6.5, 7.5 and NaCl concentrations 0 M, 0.17 M, 0.5 M, 0.6 M, 1 M. First, we conducted a residual pyrene study using gas chromatography and flame ionization technologies. Central to a gene expression study is the use of a valid endogenous reference gene, making its determination our next approach, using the geNorm/NormFinder algorithms. Armed with a valid control gene, rpoB, we applied it to a gene expression study, using the comparative critical threshold (2(ΔΔCT quantification method. The pyrene degrading activity of the strain was strongly functional in all the NaCl concentration states, with the least activity found at 1M (∼70% degraded after 48 hours of cultivation. The transcripts quantification of three genes backed this observation with high expression levels. The gene expression levels also revealed pH 6.5 as optimal for pyrene degradation and weak degradation activity at pH of 5.5, corroborating the residual pyrene analysis. The expression of these genes as proteins has already been studied in our laboratory using proteomics techniques and this validates our current study.

  17. Phytoalexins of the Pyrinae: Biphenyls and dibenzofurans

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    Cornelia Chizzali

    2012-04-01

    Full Text Available Biphenyls and dibenzofurans are the phytoalexins of the Pyrinae, a subtribe of the plant family Rosaceae. The Pyrinae correspond to the long-recognized Maloideae. Economically valuable species of the Pyrinae are apples and pears. Biphenyls and dibenzofurans are formed de novo in response to infection by bacterial and fungal pathogens. The inducible defense compounds were also produced in cell suspension cultures after treatment with biotic and abiotic elicitors. The antimicrobial activity of the phytoalexins was demonstrated. To date, 10 biphenyls and 17 dibenzofurans were isolated from 14 of the 30 Pyrinae genera. The most widely distributed compounds are the biphenyl aucuparin and the dibenzofuran γ-cotonefuran. The biosynthesis of the two classes of defense compounds is not well understood, despite the importance of the fruit crops. More recent studies have revealed simultaneous accumulation of biphenyls and dibenzofurans, suggesting sequential, rather than the previously proposed parallel, biosynthetic pathways. Elicitor-treated cell cultures of Sorbus aucuparia served as a model system for studying phytoalexin metabolism. The key enzyme that forms the carbon skeleton is biphenyl synthase. The starter substrate for this type-III polyketide synthase is benzoyl-CoA. In apples, biphenyl synthase is encoded by a gene family, members of which are differentially regulated. Metabolism of the phytoalexins may provide new tools for designing disease control strategies for fruit trees of the Pyrinae subtribe.

  18. Phytoalexins of the Pyrinae: Biphenyls and dibenzofurans.

    Science.gov (United States)

    Chizzali, Cornelia; Beerhues, Ludger

    2012-01-01

    Biphenyls and dibenzofurans are the phytoalexins of the Pyrinae, a subtribe of the plant family Rosaceae. The Pyrinae correspond to the long-recognized Maloideae. Economically valuable species of the Pyrinae are apples and pears. Biphenyls and dibenzofurans are formed de novo in response to infection by bacterial and fungal pathogens. The inducible defense compounds were also produced in cell suspension cultures after treatment with biotic and abiotic elicitors. The antimicrobial activity of the phytoalexins was demonstrated. To date, 10 biphenyls and 17 dibenzofurans were isolated from 14 of the 30 Pyrinae genera. The most widely distributed compounds are the biphenyl aucuparin and the dibenzofuran γ-cotonefuran. The biosynthesis of the two classes of defense compounds is not well understood, despite the importance of the fruit crops. More recent studies have revealed simultaneous accumulation of biphenyls and dibenzofurans, suggesting sequential, rather than the previously proposed parallel, biosynthetic pathways. Elicitor-treated cell cultures of Sorbus aucuparia served as a model system for studying phytoalexin metabolism. The key enzyme that forms the carbon skeleton is biphenyl synthase. The starter substrate for this type-III polyketide synthase is benzoyl-CoA. In apples, biphenyl synthase is encoded by a gene family, members of which are differentially regulated. Metabolism of the phytoalexins may provide new tools for designing disease control strategies for fruit trees of the Pyrinae subtribe.

  19. Isolation and Expression of 9-cis Epoxycarotenoid Dioxygenase Gene in Tree Peony%牡丹NCED基因的克隆和表达分析

    Institute of Scientific and Technical Information of China (English)

    王晓庆; 张超; 王彦杰; 董丽

    2012-01-01

    A full-length cDNA(temporarily name it Ps-NCED1)encoding 9-cis-epoxycarotenoid (NCED)was isolated with the techniques of RT-PCR and RACE from petals of tree peony flower and characterized. Phylogenetic tree analysis revealed that amino acids sequence of Ps-NCED1 shared more than 70% identity with the sequence of NCED from plants such as Vitis vinifera,Solanum tuberosum, Daucus carota and so on. Ps-NCED1 also had the highest amino acids sequence identity with At-NCED3 of CCD(carotenoid cleavage dioxygenase)family in Arabidopsis. Cut flowers during full open stage had the lowest endogenous ABA levels,to the contrary,flowers during primary and senescent stages had higher ABA levels. The relative real-time PCR analysis was used to identify the expression of Ps-NCED1 in different parts of tree peony at blooming stage. The expression in root and stamen presented the highest,while that in leaf and sepal the lowest. The expression of Ps-NCED1 in the petals from ABA treated flowers during vasing increased with cut flowers opening and senescence,coincided with the ABA content increase,resulted in the assumption that it might be the main member in regulation the ABA biosynthesis in tree peony responding to the postharvest stress during opening and senescence process.%通过RT-PCR和RACE技术克隆得到了牡丹(Paeonia suffruticosa Andr.)中编码9–顺式–环氧类胡萝卜素加双氧酶蛋白(NCED)的一条cDNA基因全长(暂命名为Ps-NCED1)。进化树分析显示Ps-NCED1的氨基酸序列与葡萄、马铃薯、胡萝卜等植物中的NCED一致性均达到了70%以上。通过与拟南芥中CCD(类胡萝卜素分解加双氧酶)家族氨基酸序列比对后发现,Ps-NCED1与调控ABA合成的At-NCED3一致性最高。对花朵中内源ABA的研究发现,ABA在花朵蕾期及衰老期含量较高,盛开期时含量较低,表明ABA对于植物的开放衰老具有促进作用。相对荧光定量PCR分析发现:在花朵完全

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

    NARCIS (Netherlands)

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

    1999-01-01

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

  1. Expression, purification and kinetic characterization of recombinant benzoate dioxygenase from Rhodococcus ruber UKMP-5M

    Directory of Open Access Journals (Sweden)

    Arezoo Tavakoli

    2016-09-01

    Full Text Available In this study, benzoate dioxygenase from Rhodococcus ruber UKMP-5M was catalyzed by oxidating the benzene ring to catechol and other derivatives. The benzoate dioxygenase (benA gene from Rhodococcus ruber UKMP-5M was then expressed, purified, characterized, The benA gene was amplified (642 bp, and the product was cloned into a pGEM-T vector.The recombinant plasmid pGEMT-benA was digested by double restriction enzymes BamHI and HindIII to construct plasmid pET28b-benA and was then ligated into Escherichia coli BL21 (DE3. The recombinant E. coli was induced with 0.5 mM isopropyl β-D-thiogalactoside (IPTG at 22˚C to produce benzoate dioxygenase. The enzyme was then purified by ion exchange chromatography after 8 purification folds. The resulting product was 25 kDa, determined by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE and western blotting. Benzoate dioxygenase activity was found to be 6.54 U/mL and the optimal pH and temperature were 8.5 and 25°C, respectively. Maximum velocity (Vmax and Michaelis constant (Km were 7.36 U/mL and 5.58 µM, respectively. The end metabolite from the benzoate dioxygenase reaction was cyclohexane dione, which was determined by gas chromatography mass spectrometry (GC-MS.

  2. Sphingobium fuliginis HC3: a novel and robust isolated biphenyl- and polychlorinated biphenyls-degrading bacterium without dead-end intermediates accumulation.

    Directory of Open Access Journals (Sweden)

    Jinxing Hu

    Full Text Available Biphenyl and polychlorinated biphenyls (PCBs are typical environmental pollutants. However, these pollutants are hard to be totally mineralized by environmental microorganisms. One reason for this is the accumulation of dead-end intermediates during biphenyl and PCBs biodegradation, especially benzoate and chlorobenzoates (CBAs. Until now, only a few microorganisms have been reported to have the ability to completely mineralize biphenyl and PCBs. In this research, a novel bacterium HC3, which could degrade biphenyl and PCBs without dead-end intermediates accumulation, was isolated from PCBs-contaminated soil and identified as Sphingobium fuliginis. Benzoate and 3-chlorobenzoate (3-CBA transformed from biphenyl and 3-chlorobiphenyl (3-CB could be rapidly degraded by HC3. This strain has strong degradation ability of biphenyl, lower chlorinated (mono-, di- and tri- PCBs as well as mono-CBAs, and the biphenyl/PCBs catabolic genes of HC3 are cloned on its plasmid. It could degrade 80.7% of 100 mg L -1 biphenyl within 24 h and its biphenyl degradation ability could be enhanced by adding readily available carbon sources such as tryptone and yeast extract. As far as we know, HC3 is the first reported that can degrade biphenyl and 3-CB without accumulation of benzoate and 3-CBA in the genus Sphingobium, which indicates the bacterium has the potential to totally mineralize biphenyl/PCBs and might be a good candidate for restoring biphenyl/PCBs-polluted environments.

  3. Hydrogen Peroxide-induced Cell Death in Arabidopsis : Transcriptional and Mutant Analysis Reveals a Role of an Oxoglutarate-dependent Dioxygenase Gene in the Cell Death Process

    NARCIS (Netherlands)

    Gechev, Tsanko S.; Minkov, Ivan N.; Hille, Jacques

    2005-01-01

    Hydrogen peroxide is a major regulator of plant programmed cell death (PCD) but little is known about the downstream genes from the H2O2-signaling network that mediate the cell death. To address this question, a novel system for studying H2O2-induced programmed cell death in Arabidopsis thaliana was

  4. Transcriptional regulation of 9-cis-epoxycarotenoid dioxygenase (NCED) gene by putrescine accumulation positively modulates ABA synthesis and drought tolerance in Lotus tenuis plants.

    Science.gov (United States)

    Espasandin, Fabiana D; Maiale, Santiago J; Calzadilla, Pablo; Ruiz, Oscar A; Sansberro, Pedro A

    2014-03-01

    The accumulation of putrescine (Put) and increased arginine decarboxylase (ADC, EC 4.1.1.19) activity levels in response to osmotic stress has been reported; however, the biological meaning of this increase remains unclear. To obtain new insights into these questions, we studied the drought response of a transgenic Lotus tenuis line that expresses the oat ADC gene, which is driven by the stress-inducible pRD29A promoter. This line contains high levels of Put with no changes in spermidine and spermine contents, even under water deficits. Our results indicate that the biochemical and morphological responses to dehydration correlate with the Put level and provide evidence that Put controls the ABA content in response to drought by modulating ABA biosynthesis at the transcriptional level.

  5. Cloning and Characterization of a Sulfonate/α-Ketoglutarate Dioxygenase from Saccharomyces cerevisiae

    OpenAIRE

    Hogan, Deborah A; Auchtung, Thomas A.; Hausinger, Robert P.

    1999-01-01

    The Saccharomyces cerevisiae open reading frame YLL057c is predicted to encode a gene product with 31.5% amino acid sequence identity to Escherichia coli taurine/α-ketoglutarate dioxygenase and 27% identity to Ralstonia eutropha TfdA, a herbicide-degrading enzyme. Purified recombinant yeast protein is shown to be an Fe(II)-dependent sulfonate/α-ketoglutarate dioxygenase. Although taurine is a poor substrate, a variety of other sulfonates are utilized, with the best natural substrates being is...

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

    Science.gov (United States)

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

    2012-01-01

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

  7. Isolation of bacterial strains able to degrade biphenyl, diphenyl ether and the heat transfer fluid used in thermo-solar plants.

    Science.gov (United States)

    Blanco-Moreno, Rafael; Sáez, Lara P; Luque-Almagro, Víctor M; Roldán, M Dolores; Moreno-Vivián, Conrado

    2017-03-25

    Thermo-solar plants use eutectic mixtures of diphenyl ether (DE) and biphenyl (BP) as heat transfer fluid (HTF). Potential losses of HTF may contaminate soils and bioremediation is an attractive tool for its treatment. DE- or BP-degrading bacteria are known, but up to now bacteria able to degrade HTF mixture have not been described. Here, five bacterial strains which are able to grow with HTF or its separate components DE and BP as sole carbon sources have been isolated, either from soils exposed to HTF or from rhizospheric soils of plants growing near a thermo-solar plant. The organisms were identified by 16S rRNA gene sequencing as Achromobacter piechaudii strain BioC1, Pseudomonas plecoglossicida strain 6.1, Pseudomonas aeruginosa strains HBD1 and HBD3, and Pseudomonas oleovorans strain HBD2. Activity of 2,3-dihydroxybiphenyl dioxygenase (BphC), a key enzyme of the biphenyl upper degradation pathway, was detected in all isolates. Pseudomonas strains almost completely degraded 2000ppm HTF after 5-day culture, and even tolerated and grew in the presence of 150,000ppm HTF, being suitable candidates for in situ soil bioremediation. Degradation of both components of HTF is of particular interest since in the DE-degrader Sphingomonas sp. SS3, growth on DE or benzoate was strongly inhibited by addition of BP.

  8. Cytochrome P4501A induction in avian hepatocyte cultures exposed to polychlorinated biphenyls: Comparisons with AHR1-mediated reporter gene activity and in ovo toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Manning, Gillian E., E-mail: gmann017@uottawa.ca [Centre for Advanced Research in Environmental Genomics, Department of Biology, University of Ottawa, Ottawa, ON, Canada K1N 6N5 (Canada); Environment Canada, National Wildlife Research Centre, Ottawa, ON, Canada K1A 0H3 (Canada); Mundy, Lukas J., E-mail: lukas.mundy@ec.gc.ca [Centre for Advanced Research in Environmental Genomics, Department of Biology, University of Ottawa, Ottawa, ON, Canada K1N 6N5 (Canada); Environment Canada, National Wildlife Research Centre, Ottawa, ON, Canada K1A 0H3 (Canada); Crump, Doug, E-mail: doug.crump@ec.gc.ca [Environment Canada, National Wildlife Research Centre, Ottawa, ON, Canada K1A 0H3 (Canada); Jones, Stephanie P., E-mail: stephanie.jones@ec.gc.ca [Environment Canada, National Wildlife Research Centre, Ottawa, ON, Canada K1A 0H3 (Canada); Chiu, Suzanne, E-mail: suzanne.chiu@ec.gc.ca [Environment Canada, National Wildlife Research Centre, Ottawa, ON, Canada K1A 0H3 (Canada); Klein, Jeff, E-mail: jeffery@well-labs.com [Wellington Laboratories Inc., Research Division, Guelph, ON, Canada N1G 3chsM5 (Canada); Konstantinov, Alex, E-mail: alex@well-labs.com [Wellington Laboratories Inc., Research Division, Guelph, ON, Canada N1G 3chsM5 (Canada); Potter, Dave, E-mail: dpotter@well-labs.com [Wellington Laboratories Inc., Research Division, Guelph, ON, Canada N1G 3chsM5 (Canada); Kennedy, Sean W., E-mail: sean.kennedy@ec.gc.ca [Centre for Advanced Research in Environmental Genomics, Department of Biology, University of Ottawa, Ottawa, ON, Canada K1N 6N5 (Canada); Environment Canada, National Wildlife Research Centre, Ottawa, ON, Canada K1A 0H3 (Canada)

    2013-01-01

    Avian-specific toxic equivalency factors (TEFs) were developed by the World Health Organization to simplify environmental risk assessments of dioxin-like compounds (DLCs), but TEFs do not account for differences in the toxic and biochemical potencies of DLCs among species of birds. Such variability may be due to differences in species sensitivity to individual DLCs. The sensitivity of avian species to DLCs was recently associated with the identity of amino acids 324 and 380 in the aryl hydrocarbon receptor 1 (AHR1) ligand binding domain. A luciferase reporter gene (LRG) assay, measuring AHR1-mediated induction of a cytochrome P450 1A5 (CYP1A5) reporter gene, in combination with a species' AHR1 ligand binding domain sequence, were also shown to predict avian species sensitivity to polychlorinated biphenyls (PCBs) and PCB relative potency in a given species. The goals of the present study were to (1) characterize the concentration-dependent effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin and PCBs 126, 77, 105 and 118 on induction of ethoxyresorufin O-deethylase (EROD) activity and CYP1A4/5 mRNA in chicken, ring-necked pheasant and Japanese quail embryo hepatocytes and (2) compare these in vitro results to those previously generated by the LRG assay and in ovo toxicity studies. EROD activity and CYP1A4/5 mRNA expression data support and complement the findings of the LRG assay. CYP1A enzyme activity and mRNA expression were significantly correlated both with luciferase activity and in ovo toxicity induced by PCBs. Relative potency values were generally similar between the LRG and EROD assays and indicate that the relative potency of some PCBs may differ among species. -- Highlights: ► The chicken isn't the most sensitive species to CYP1A induction by PCB 105 and 118. ► The relative potency of PCBs differs between avian species. ► EROD activity was correlated with luciferase activity from the LRG assay. ► EROD activity was a better predictor of

  9. 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....

  10. Discovery of Key Dioxygenases that Diverged the Paraherquonin and Acetoxydehydroaustin Pathways in Penicillium brasilianum.

    Science.gov (United States)

    Matsuda, Yudai; Iwabuchi, Taiki; Fujimoto, Takayuki; Awakawa, Takayoshi; Nakashima, Yu; Mori, Takahiro; Zhang, Huiping; Hayashi, Fumiaki; Abe, Ikuro

    2016-09-28

    Paraherquonin (1), a fungal meroterpenoid produced by Penicillium brasilianum NBRC 6234, possesses a unique, highly congested hexacyclic molecular architecture. Here we identified the biosynthetic gene cluster of 1 (the prh cluster) and elucidated the pathway up to berkeleydione (2), which serves as the key intermediate for the biosynthesis of 1 as well as many other meroterpenoids. Interestingly, the nonheme iron and α-ketoglutarate-dependent dioxygenase PrhA constructs the cycloheptadiene moiety to afford 2 from preaustinoid A1 (6), probably via the homoallyl-homoallyl radical rearrangement. Additionally, another fungal strain, P. brasilianum MG11, which produces acetoxydehydroaustin instead of 1, was found to have a gene cluster nearly identical to the prh cluster. The dioxygenase encoded by the cluster shares 92% sequence identity with PrhA, and also accepts 6 but produces preaustinoid A3 (17) with a spiro-lactone system, generating a diverging point for the two different meroterpenoid pathways in the same species.

  11. Characterization of an indoleamine 2,3-dioxygenase-like protein found in humans and mice.

    Science.gov (United States)

    Ball, Helen J; Sanchez-Perez, Angeles; Weiser, Silvia; Austin, Christopher J D; Astelbauer, Florian; Miu, Jenny; McQuillan, James A; Stocker, Roland; Jermiin, Lars S; Hunt, Nicholas H

    2007-07-01

    Indoleamine 2,3-dioxygenase (INDO) and tryptophan 2,3-dioxygenase (TDO) each catalyze the first step in the kynurenine pathway of tryptophan metabolism. We describe the discovery of another enzyme with this activity, indoleamine 2,3-dioxygenase-like protein (INDOL1), which is closely related to INDO and is expressed in mice and humans. The corresponding genes have a similar genomic structure and are situated adjacent to each other on human and mouse chromosome 8. They are likely to have arisen by gene duplication before the origin of the tetrapods. The expression of INDOL1 is highest in the mouse kidney, followed by epididymis, and liver. Expression of mouse INDOL1 was further localized to the tubular cells in the kidney and the spermatozoa. INDOL1 was assigned its name because of its structural similarity to INDO. We demonstrate that INDOL1 catalyses the conversion of tryptophan to kynurenine therefore a more appropriate nomenclature for the enzymes might be INDO-1 and INDO-2, or the more commonly-used abbreviations, IDO-1 and IDO-2. Although the two proteins have similar enzymatic activities, their different expression patterns within tissues and during malaria infection, suggests a distinct role for each protein. This identification of INDOL1 may help to explain the regulation of the diversity of physiological and patho-physiological processes in which the kynurenine pathway is involved.

  12. Loss of ETHE1, a mitochondrial dioxygenase, causes fatal sulfide toxicity in ethylmalonic encephalopathy.

    Science.gov (United States)

    Tiranti, Valeria; Viscomi, Carlo; Hildebrandt, Tatjana; Di Meo, Ivano; Mineri, Rossana; Tiveron, Cecilia; Levitt, Michael D; Prelle, Alessandro; Fagiolari, Gigliola; Rimoldi, Marco; Zeviani, Massimo

    2009-02-01

    Ethylmalonic encephalopathy is an autosomal recessive, invariably fatal disorder characterized by early-onset encephalopathy, microangiopathy, chronic diarrhea, defective cytochrome c oxidase (COX) in muscle and brain, high concentrations of C4 and C5 acylcarnitines in blood and high excretion of ethylmalonic acid in urine. ETHE1, a gene encoding a beta-lactamase-like, iron-coordinating metalloprotein, is mutated in ethylmalonic encephalopathy. In bacteria, ETHE1-like sequences are in the same operon of, or fused with, orthologs of TST, the gene encoding rhodanese, a sulfurtransferase. In eukaryotes, both ETHE1 and rhodanese are located within the mitochondrial matrix. We created a Ethe1(-/-) mouse that showed the cardinal features of ethylmalonic encephalopathy. We found that thiosulfate was excreted in massive amounts in urine of both Ethe1(-/-) mice and humans with ethylmalonic encephalopathy. High thiosulfate and sulfide concentrations were present in Ethe1(-/-) mouse tissues. Sulfide is a powerful inhibitor of COX and short-chain fatty acid oxidation, with vasoactive and vasotoxic effects that explain the microangiopathy in ethylmalonic encephalopathy patients. Sulfide is detoxified by a mitochondrial pathway that includes a sulfur dioxygenase. Sulfur dioxygenase activity was absent in Ethe1(-/-) mice, whereas it was markedly increased by ETHE1 overexpression in HeLa cells and Escherichia coli. Therefore, ETHE1 is a mitochondrial sulfur dioxygenase involved in catabolism of sulfide that accumulates to toxic levels in ethylmalonic encephalopathy.

  13. Isolation, degradation characteristics and catechol 1,2 dioxygenase gene expression level of 1,2,4-TCB degrading bacterium under low temperature%低温1,2,4-TCB降解菌的选育、降解特性及邻苯二酚1,2-双加氧酶基因表达水平

    Institute of Scientific and Technical Information of China (English)

    胡日查; 孙立波

    2013-01-01

    从长期受l,2,4-三氯苯(1,2,4-TCB)污染的地下水中筛选出一株低温寡营养降解菌A2,对A2菌进行革兰氏染色鉴定和16S rDNA鉴定,研究了不同pH、温度、盐度等因素对A2菌降解l,2,4-TCB效果以及对邻苯二酚l,2-双加氧酶基因表达的影响,并进行了正交实验.结果表明,A2菌为革兰氏阴性短杆细菌,初步鉴定为假单胞菌;在pH值为7、培养温度30℃、盐度0.8%、培养时间6d时,A2菌对1,2,4-TCB降解效果最好,降解率达到88.14%,同时该条件下邻苯二酚1,2-双加氧酶基因相对表达水平最高;培养温度为10℃时,A2菌对1,2,4-TCB降解率可达到85.3%,同时邻苯二酚l,2-双加氧酶基因也有较高的相对表达水平 以上结果说明,将A2菌应用于低温寡营养地下水的生物修复是可能的.%An oligotrophic degrading bacterium named strain A2 was screened from groundwater long-term contaminated by 1 , 2 , 4-TCB under low temperature condition, strain A2 was identified by gram stain and 16S rDNA sequence, the impacts of different pH, temperature, salinity on degradation effect and catechol 1 ,2 dioxyge-nase gene expression level were studied, and orthogonality experiment was carried out. The results showed that strain A2 was gram negative short rods, and was identified as pseudomonas preliminarily. The degrading effect of strain A2 on 1 ,2,4-TCB and catechol 1 ,2 dioxygenase gene expression level showed best under the conditions; pH of 7, cultivation temperature of 30℃ , salinity of 0.8% , cultivation time of 6 days, and the degrading rate could reach 88. 14% . The degrading rate of 1 ,2,4-TCB by strain A2 could reach 85.3% at 10℃ , and catechol 1 ,2 dioxygenase gene expression level also showed a relative high expression level. This research demonstrated that it is possible to apply strain A2 in the bioremediation of oligotrophic groundwater under low temperature condition.

  14. Disruption of thyroid hormone (TH) levels and TH-regulated gene expression by polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and hydroxylated PCBs in e-waste recycling workers.

    Science.gov (United States)

    Zheng, Jing; He, Chun-Tao; Chen, She-Jun; Yan, Xiao; Guo, Mi-Na; Wang, Mei-Huan; Yu, Yun-Jiang; Yang, Zhong-Yi; Mai, Bi-Xian

    2017-02-25

    Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) are the primary toxicants released by electronic waste (e-waste) recycling, but their adverse effects on people working in e-waste recycling or living near e-waste sites have not been studied well. In the present study, the serum concentrations of PBDEs, PCBs, and hydroxylated PCBs, the circulating levels of thyroid hormones (THs), and the mRNA levels of seven TH-regulated genes in peripheral blood leukocytes of e-waste recycling workers were analyzed. The associations of the hormone levels and gene expression with the exposure to these contaminants were examined using multiple linear regression models. There were nearly no associations of the TH levels with PCBs and hydroxylated PCBs, whereas elevated hormone (T4 and T3) levels were associated with certain lower-brominated BDEs. While not statistically significant, we did observe a negative association between highly brominated PBDE congeners and thyroid-stimulating hormone (TSH) levels in the e-waste workers. The TH-regulated gene expression was more significantly associated with the organohalogen compounds (OHCs) than the TH levels in these workers. The TH-regulated gene expression was significantly associated with certain PCB and hydroxylated PCB congeners. However, the expression of most target genes was suppressed by PBDEs (mostly highly brominated congeners). This is the first evidence of alterations in TH-regulated gene expression in humans exposed to OHCs. Our findings indicated that OHCs may interfere with TH signaling and/or exert TH-like effects, leading to alterations in related gene expression in humans. Further research is needed to investigate the mechanisms of action and associated biological consequences of the gene expression disruption by OHCs.

  15. Isolation,Charcaterization of an Anthracene Degrading Bacterium Martelella sp. AD-3 and Cloning of Dioxygenase Gene%降解蒽嗜盐菌AD-3的筛选、降解特性及加氧酶基因的研究

    Institute of Scientific and Technical Information of China (English)

    崔长征; 冯天才; 于亚琦; 董婓; 杨昕梅; 冯耀宇; 刘勇弟; 林汉平

    2012-01-01

    Anthracene,among the 16 US EPA polycyclic aromatic hydrocarbons(PAHs),is a typical low molecular weight environmental contaminant,which gains concern on its biodegradation under hypersaline condition.In this study,an anthracene-degrading bacterial strain was isolated from highly saline petroleum-contaminated soil.Based on its physiological,biochemical characteristics and 16S rDNA sequence analysis,the bacteria was preliminary identified and named as Martelella sp. AD-3.The strain was able to utilize anthracene as sole carbon source for growth and the degradation occurred under broad salinities(0.1% to 10%) and varying pHs(6.0 to 10.0).The optimized degradation conditions were initial concentration 25 mg·L^-1,culture temperature 30℃,pH 9.0 and salinity 3%.And 94.6% of anthracene was degraded by strain AD-3 under the optimal conditions within 6 days.Degenerate primers design was performed with a reported dioxygenase α subunit homologous gene.A length of 307 bp fragment of the partial dioxygenase gene sequences(GenBank accession: JF823991.1) was amplified by nested PCR.The clones amino acid sequence from strain AD-3 showed 95% identity to that of the partial naphthalene dioxygenase large-subunit from Marinobacter sp. NCE312(AF295033).The results lay a foundation for the further study of molecular mechanism involved in the PAHs biodegradation by strain AD-3.%蒽是典型的多环芳烃类环境污染物,属于美国EPA优先控制的16种多环芳烃类化合物,其在高盐环境下的生物降解备受关注.本研究从某石油污染的高盐土壤中成功筛选出了1株高效降解蒽的菌株,经过对其生理生化特征和16S rDNA序列分析,初步鉴定并命名该菌株为Martelella sp.AD-3.该菌株在0.1%~10%的盐度和6.0~10.0的pH范围内,均能够降解蒽.其生长和降解蒽的优化条件是:蒽初始浓度25 mg·L^-1、温度30℃、pH值9.0和盐度3%,在优化条件下培养6 d,蒽的降解率可达到94.6%.根据已报道的双

  16. Heme-containing dioxygenases involved in tryptophan oxidation.

    Science.gov (United States)

    Millett, Elizabeth S; Efimov, Igor; Basran, Jaswir; Handa, Sandeep; Mowat, Christopher G; Raven, Emma Lloyd

    2012-04-01

    Heme iron is often used in biology for activation of oxygen. The mechanisms of oxygen activation by heme-containing monooxygenases (the cytochrome P450s) are well known, and involve formation of a Compound I species, but information on the heme-containing dioxygenase enzymes involved in tryptophan oxidation lags far behind. In this review, we gather together information emerging recently from structural, mechanistic, spectroscopic, and computational approaches on the heme dioxygenase enzymes involved in tryptophan oxidation. We explore the subtleties that differentiate various heme enzymes from each other, and use this to piece together a developing picture for oxygen activation in this particular class of heme-containing dioxygenases.

  17. Isolation of oxygenase genes for indigo-forming activity from an artificially polluted soil metagenome by functional screening using Pseudomonas putida strains as hosts.

    Science.gov (United States)

    Nagayama, Hirofumi; Sugawara, Tomonori; Endo, Ryo; Ono, Akira; Kato, Hiromi; Ohtsubo, Yoshiyuki; Nagata, Yuji; Tsuda, Masataka

    2015-05-01

    Metagenomes contain the DNA from many microorganisms, both culturable and non-culturable, and are a potential resource of novel genes. In this study, a 5.2-Gb metagenomic DNA library was constructed from a soil sample (artificially polluted with four aromatic compounds, i.e., biphenyl, phenanthrene, carbazole, and 3-chlorobenzoate) in Escherichia coli by using a broad-host-range cosmid vector. The resultant library was introduced into naphthalene-degrading Pseudomonas putida-derived strains having deficiencies in their naphthalene dioxygenase components, and indigo-forming clones on the indole-containing agar plates were screened. Cosmids isolated from 29 positive clones were classified by their various properties (original screening hosts, hosts showing indigo-forming activity, and digestion patterns with restriction enzymes), and six representative cosmids were chosen. Sequencing and in vitro transposon mutagenesis of the six cosmids resulted in the identification of genes encoding putative class B and D flavoprotein monooxygenases, a multicomponent hydroxylase, and a reductase that were responsible for the indigo-forming activity in the host cells. Among them, the genes encoding the multicomponent hydroxylase were demonstrated to be involved in phenol degradation. Furthermore, two genes encoding ring-cleavage dioxygenases were also found adjacent to the genes responsible for the indigo formation, and their functions were experimentally confirmed.

  18. Hemoglobin: A Nitric-Oxide Dioxygenase

    Directory of Open Access Journals (Sweden)

    Paul R. Gardner

    2012-01-01

    Full Text Available Members of the hemoglobin superfamily efficiently catalyze nitric-oxide dioxygenation, and when paired with native electron donors, function as NO dioxygenases (NODs. Indeed, the NOD function has emerged as a more common and ancient function than the well-known role in O2 transport-storage. Novel hemoglobins possessing a NOD function continue to be discovered in diverse life forms. Unique hemoglobin structures evolved, in part, for catalysis with different electron donors. The mechanism of NOD catalysis by representative single domain hemoglobins and multidomain flavohemoglobin occurs through a multistep mechanism involving O2 migration to the heme pocket, O2 binding-reduction, NO migration, radical-radical coupling, O-atom rearrangement, nitrate release, and heme iron re-reduction. Unraveling the physiological functions of multiple NODs with varying expression in organisms and the complexity of NO as both a poison and signaling molecule remain grand challenges for the NO field. NOD knockout organisms and cells expressing recombinant NODs are helping to advance our understanding of NO actions in microbial infection, plant senescence, cancer, mitochondrial function, iron metabolism, and tissue O2 homeostasis. NOD inhibitors are being pursued for therapeutic applications as antibiotics and antitumor agents. Transgenic NOD-expressing plants, fish, algae, and microbes are being developed for agriculture, aquaculture, and industry.

  19. Structure and mechanism of mouse cysteine dioxygenase

    Science.gov (United States)

    McCoy, Jason G.; Bailey, Lucas J.; Bitto, Eduard; Bingman, Craig A.; Aceti, David J.; Fox, Brian G.; Phillips, George N.

    2006-01-01

    Cysteine dioxygenase (CDO) catalyzes the oxidation of l-cysteine to cysteine sulfinic acid. Deficiencies in this enzyme have been linked to autoimmune diseases and neurological disorders. The x-ray crystal structure of CDO from Mus musculus was solved to a nominal resolution of 1.75 Å. The sequence is 91% identical to that of a human homolog. The structure reveals that CDO adopts the typical β-barrel fold of the cupin superfamily. The NE2 atoms of His-86, -88, and -140 provide the metal binding site. The structure further revealed a covalent linkage between the side chains of Cys-93 and Tyr-157, the cysteine of which is conserved only in eukaryotic proteins. Metal analysis showed that the recombinant enzyme contained a mixture of iron, nickel, and zinc, with increased iron content associated with increased catalytic activity. Details of the predicted active site are used to present and discuss a plausible mechanism of action for the enzyme. PMID:16492780

  20. Expression Pattern and Clinicopathological Relevance of the Indoleamine 2,3-Dioxygenase 1/Tryptophan 2,3-Dioxygenase Protein in Colorectal Cancer

    Directory of Open Access Journals (Sweden)

    I-Chien Chen

    2016-01-01

    Full Text Available Aims. Cancer cells use the indoleamine 2,3-dioxygenase 1 (IDO1 pathway to suppress the host’s immune response in order to facilitate survival, growth, invasion, and metastasis of malignant cells. Higher IDO1 expression was shown to be involved in colorectal cancer (CRC progression and to be correlated with impaired clinical outcome. However, the potential correlation between the expression of IDO1 in a CRC population with a low mutation rate of the APC gene remains unknown. Material and Methods. Tissues and blood samples were collected from 192 CRC patients. The expressions of IDO1, tryptophan 2,3-dioxygenase (TDO2, and beta-catenin proteins were analyzed by immunohistochemistry. Microsatellite instability (MSI was determined by PCR amplification of microsatellite loci. Results. The results showed that high IDO1 or TDO2 protein expression was associated with characteristics of more aggressive phenotypes of CRC. For the first time, they also revealed a positive correlation between the abnormal expression of beta-catenin and IDO1 or TDO2 proteins in a CRC population with a low mutation rate of APC. Conclusion. We concluded that an IDO1-regulated molecular pathway led to abnormal expression of beta-catenin in the nucleus/cytoplasm of CRC patients with low mutation rate of APC, making IDO1 an interesting target for immunotherapy in CRC.

  1. Non-coplanar polychlorinated biphenyls (PCBs) are direct agonists for the human pregnane-X receptor and constitutive androstane receptor, and activate target gene expression in a tissue-specific manner

    Energy Technology Data Exchange (ETDEWEB)

    Al-Salman, Fadheela; Plant, Nick, E-mail: N.Plant@Surrey.ac.uk

    2012-08-15

    The polychlorinated biphenyl group possesses high environmental persistence, leading to bioaccumulation and a number of adverse effects in mammals. Whilst coplanar PCBs elicit their toxic effects through agonism of the aryl hydrocarbon receptor; however, non-coplanar PCBs are not ligands for AhR, but may be ligands for members of the nuclear receptor family of proteins. To better understand the biological actions of non-coplanar PCBs, we have undertaken a systematic analysis of their ability to activate PXR and CAR-mediated effects. Cells were exposed to a range of non-coplanar PCBs (99, 138, 153, 180 and 194), or the coplanar PCB77: Direct activation of PXR and CAR was measured using a mammalian receptor activation assay in human liver cells, with rifampicin and CITCO used as positive controls ligands for PXR and CAR, respectively; activation of target gene expression was examined using reporter gene plasmids for CYP3A4 and MDR1 transfected into liver, intestine and lung cell lines. Several of the non-coplanar PCBs directly activated PXR and CAR, whilst the coplanar PCB77 did not. Non-coplanar PCBs were also able to activate PXR/CAR target gene expression in a substitution- and tissue-specific manner. Non-coplanar PCBs act as direct activators for the nuclear receptors PXR and CAR, and are able to elicit transcriptional activation of target genes in a substitution- and tissue-dependent manner. Chronic activation of PXR/CAR is linked to adverse effects and must be included in any risk assessment of PCBs. -- Highlights: ► Several Non-coplanar PCBs are able to directly activate both PXR and CAR in vitro. ► PCB153 is the most potent direct activator of PXR and CAR nuclear receptors. ► Non-coplanar PCB activation of CYP3A4/MDR1 reporter genes is structure-dependent. ► Non-coplanar PCB activate CYP3A4/MDR1 reporter genes in a tissue-dependent. ► PCB153 is the most potent activator of PXR/CAR target gene in all tissues.

  2. Cloning of 9-cis-epoxycarotenoid dioxygenase (NCED) gene encoding a key enzyme during abscisic acid (ABA) biosynthesis and ABA-regulated ethylene production in detached young persimmon calyx

    Institute of Scientific and Technical Information of China (English)

    LENG Ping; ZHANG GuangLian; LI XiangXin; WANG LiangHe; ZHENG ZhongMing

    2009-01-01

    Unlike the typical climacteric fruits,persimmons (Diospyros kaki Thunb.) produce higher levels of ethylene when they are detached from trees at a younger stage.In order to obtain detailed information on the role of abscisic acid (ABA) in ripening,we cloned the DKNCED1,DKACS2,and DKAC01 genes from the calyx.Water loss was first noted in the calyx lobe,and DKNCED1 was highly expressed 1 d after the fruits were detached,coinciding with an increase in the ABA content.Then,the DKACS2 and DKAC01 genes were expressed after some delay.In the calyx,the ABA peak was observed 2 d after the fruits were harvested,and this peak preceded the ethylene peak observed on day 3.The fruit firmness rapidly decreased on day 4,and the fruits softened completely 6 d after they were harvested.The increases in the expressions of ABA,ethylene,and the genes in the calyxes occurred earlier than the corresponding increases in the pulp,although the 3 increases occurred on different days.Exogenous ABA treatment increased ABA concentration,induced expression of both ACS and ACO,and promoted ethylene synthesis and young-fruit softening;by contrast,treatment with NDGA inhibited the gene expressions and ethylene synthesis and delayed young-fruit softening.These results indicate that ethylene biosynthesis in the detached young persimmon fruits is initially triggered by ABA,which is induced by water loss in the calyx,through the induction of DKACS2 and DKAC01 expressions.The ethylene produced in the calyx subsequently diffuses into the pulp tissue,where it induces autocatalytic ethylene biosynthesis,resulting in an abrupt increase in ethylene production.

  3. Assays of polychlorinated biphenyl congeners and co-contaminated heavy metals in the transgenic Arabidopsis plants carrying the recombinant guinea pig aryl hydrocarbon receptor-mediated β-glucuronidase reporter gene expression system.

    Science.gov (United States)

    Shimazu, Sayuri; Ohta, Masaya; Ohkawa, Hideo; Ashida, Hitoshi

    2012-01-01

    The transgenic Arabidopsis plant XgD2V11-6 carrying the recombinant guinea pig (g) aryl hydrocarbon receptor (AhR)-mediated β-glucuronidase (GUS) reporter gene expression system was examined for assay of polychlorinated biphenyl (PCB) congeners and co-contaminated heavy metals. When the transgenic Arabidopsis plants were treated with PCB126 (toxic equivalency factor; TEF: 0.1) and PCB169 (TEF: 0.03), the GUS activity of the whole plants was increased significantly. After treatment with PCB80 (TEF: 0), the GUS activity was nearly the same level as that treated with 0.1% dimethylsulfoxide (DMSO) as a vehicle control. After exposure to a 1:1 mixture of PCB126 and PCB169, the GUS activity was increased additively. However, after exposure to a mixture of PCB126 and PCB80, the GUS activity was lower than that of the treatment with PCB126 alone. Thus, PCB80 seemed to be an antagonist towards AhR. When the transgenic plants were treated with each of the heavy metals Fe, Cu, Zn, Cd and Pb together with PCB126, Cd and Pb increased the PCB126-induced GUS activity. On the other hand, Fe, Cu and Zn did not affect the PCB126-induced GUS activity. In the presence of the biosurfactant mannosylerythritol lipid-B (MEL-B) and the carrier protein bovine serum albumin (BSA), the PCB126-induced GUS activity was increased, but the Cd-assisted PCB126-induced GUS activity was not affected. Thus, MEL-B and BSA seemed to increase uptake and transport of PCB126, respectively.

  4. Sequence of the bphD gene encoding 2-hydroxy-6-oxo-(phenyl/chlorophenyl)hexa-2,4-dienoic acid (HOP/cPDA) hydrolase involved in the biphenyl/polychlorinated biphenyl degradation pathway in Comamonas testosteroni: evidence suggesting involvement of Ser112 in catalytic activity.

    Science.gov (United States)

    Ahmad, D; Fraser, J; Sylvestre, M; Larose, A; Khan, A; Bergeron, J; Juteau, J M; Sondossi, M

    1995-04-14

    The nucleotide sequence of bphD, encoding 2-hydroxy-6-oxo-(phenyl/chlorophenyl)hexa-2,4-dienoic acid hydrolase involved in the biphenyl/polychlorinated biphenyl degradation pathway of Comamonas testosteroni strain B-356, was determined. Comparison of the deduced amino-acid sequence with published sequences led to the identification of a 'lipase box', containing a consensus pentapeptide sequence GlyXaaSerXaaGly. This suggested that the mechanism of action of this enzyme may involve an Asp-Ser-His catalytic triad similar to that of classical lipases and serine hydrolases. Further biochemical and genetic evidence for the active-site involvement of Ser112 was obtained by showing that a semipurified enzyme was inhibited by PMSF, a classic inhibitor of serine hydrolases, and by site-directed Ser112-->Ala mutagenesis.

  5. The Role of 4-Hydroxyphenylpyruvate Dioxygenase in Enhancement of Solid-Phase Electron Transfer by Shewanella oneidensis MR-1

    Energy Technology Data Exchange (ETDEWEB)

    Turick, Charles E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Beliaev, Alex S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Zakrajsek, Brian A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Reardon, Catherine L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lowy, Daniel A. [Nova Research Inc., Alexandria, VA (United States); Poppy, Tara E. [Univ. of South Carolina, Aiken, SC (United States); Maloney, Andrea [Winthrop Univ., Rock Hill, SC (United States); Ekechukwu, Amy A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2009-05-01

    ABSTRACT - 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 electron shuttling compounds. This study focuses on the production of homogensitate in Shewanella oneidensis MR-1, an intermediate of the tyrosine degradation pathway, which is a precursor of a redox cycling metabolite, pyomelanin. 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 at 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°') of S. oneidensis MR-1. Based on our findings, environmental production of pyomelanin likely contributes to an increased solid-phase metal reduction capacity in S. oneidensis MR-1.

  6. 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.

  7. Hunting down frame shifts: Ecological analysis of diverse functional gene sequences

    Directory of Open Access Journals (Sweden)

    Michal eStrejcek

    2015-11-01

    Full Text Available Functional gene ecological analyses using amplicon sequencing can be challenging as translated sequences are often burdened with shifted reading frames. The aim of this work was to evaluate several bioinformatics tools designed to correct errors which arise during sequencing in an effort to reduce the number of frame-shifts (FS. Genes encoding for alpha subunits of biphenyl (bphA and benzoate (benA dioxygenases were used as model sequences. FrameBot, a FS correction tool, was able to reduce the number of detected FS to zero. However, up to 43.1% of sequences were discarded by FrameBot as non-specific targets. Therefore, we proposed a de novo mode of FrameBot for FS correction, which works on a similar basis as common chimera identifying platforms and is not dependent on reference sequences. By nature of FrameBot de novo design, it is crucial to provide it with data as error free as possible. We tested the ability of several publicly available correction tools to decrease the number of errors in the data sets. The combination of Maximum Expected Error (MEE filtering and single linkage pre-clustering (SLP proved the most efficient read procession. Applying FrameBot de novo on the processed data enabled analysis of BphA sequences with minimal losses of potentially functional sequences not homologous to those previously known. This experiment also demonstrated the extensive diversity of dioxygenases in soil. A script which performs FrameBot de novo is presented in the supplementary material to the study and the tool was implemented into FunGene Pipeline available at http://fungene.cme.msu.edu/FunGenePipeline/ and https://github.com/rdpstaff/Framebot.

  8. Biosynthesis of the biphenyl phytoalexin aucuparin in Sorbus aucuparia cell cultures treated with Venturia inaequalis.

    Science.gov (United States)

    Khalil, Mohammed N A; Beuerle, Till; Müller, Andreas; Ernst, Ludger; Bhavanam, Vijaya B R; Liu, Benye; Beerhues, Ludger

    2013-12-01

    Aucuparin is the most widely distributed biphenyl phytoalexin in the rosaceous subtribe Pyrinae, which includes the economically important fruit trees apple and pear. The biphenyl scaffold is formed by biphenyl synthase, which catalyzes biosynthesis of 3,5-dihydroxybiphenyl. Conversion of this precursor to aucuparin (3,5-dimethoxy-4-hydroxybiphenyl) was studied in cell cultures of Sorbus aucuparia after treatment with an elicitor preparation from the scab-causing fungus Venturia inaequalis. The sequence of the biosynthetic steps detected was O-methylation - 4-hydroxylation - O-methylation. The two alkylation reactions were catalyzed by distinct methyltransferases, which differed in pH and temperature optima as well as stability. Biphenyl 4-hydroxylase was a microsomal cytochrome P450 monooxygenase, whose activity was appreciably decreased by the addition of established P450 inhibitors. When fed to V. inaequalis-treated S. aucuparia cell cultures, radioactively labeled 3,5-dihydroxybiphenyl was not only incorporated into aucuparin but also into the dibenzofuran eriobofuran, the accumulation of which paralleled that of aucuparin. However, biphenyl 2'-hydroxylase activity proposed to be involved in dibenzofuran formation was detected in neither microsomes nor cell-free extracts in the presence of NADPH and 2-oxoglutarate, respectively. Nevertheless, a basis for studying biphenyl biosynthesis at the gene level is provided.

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

    Directory of Open Access Journals (Sweden)

    Andréa Scaramal Silva

    2012-01-01

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

  10. In vitro antiestrogenic effects of aryl methyl sulfone metabolites of polychlorinated biphenyls and 2,2-bis(4-chlorophenyl)-1,1-dichloroethene on 17beta-estradiol-induced gene expression in several bioassay systems.

    Science.gov (United States)

    Letcher, Robert J; Lemmen, Josephine G; van der Burg, Bart; Brouwer, Abraham; Bergman, Ake; Giesy, John P; van den Berg, Martin

    2002-10-01

    Methylsulfonyl (MeSO(2)) metabolites of polychlorinated biphenyls (PCBs) and 2,2-bis(4-chlorophenyl)-1,1-dichloroethene (4,4'-DDE), itself a metabolite of the insecticide 4,4'-DDT, are emerging as a major class of contaminants in the tissues of wildlife and humans. We investigated the antiestrogenic capacity and potencies of 3'- and 4'-MeSO(2)-2,2',4,5,5'-pentachlorobiphenyl (CB101) and -2,2',4,5'-tetrachlorobiphenyl (CB49), which are among the most environmentally persistent MeSO(2)-PCBs, and 3-MeSO(2)-4,4'-DDE on estrogen receptor (ER)-dependent gene expression in four cell-based bioassay systems. Congener- and concentration-dependent antagonism of 17beta-estradiol (E2)-induced gene expression, rather than induction of ER-dependent gene expression, was observed for the MeSO(2)-PCBs on lucifierase activity in stably transfected human breast adenocarcinoma T47D cells (ER-CALUX) and vitellogenin (vtg) production in primary hepatocytes from male carp fish (Cyprinus carpio) (CARP-HEP/vtg). 4'-MeSO(2)-CB101 and -CB49 had the highest antagonistic potency (i.e., maximum inhibition of about 70%, LOECs of 1.0 microM and 2.5 microM), whereas 3'-MeSO(2)-CB101 and -CB49 were less antagonistic; the precursor CB101 and MeSO(2)-PCB analog MeSO(2)-2,5-dichlorobenzene had no effect. Relative to the 4-MeSO(2)-PCBs, tamoxifen (IC(50), 0.06 microM and 0.7 microM) was about 40 and 7 times more potent in the ER-CALUX and CARP-HEP/vtg assays, respectively. Congener- and concentration-dependent effects on aryl hydrocarbon receptor-mediated induction of EROD activity (carp hepatocytes), luciferase expression (H4IIE rat hepatoma [H4IIE.luc] cell line), or cell viability were not observed. 3-MeSO(2)-4,4'-DDE was neither estrogenic nor antiestrogenic in either of the bioassays. Inhibitory trends for the MeSO(2)-PCBs in a bioassay based on stably transfected human embryonic kidney cell (HEK293-ERalpha-ERE) were similar to the ER-CALUX and CARP-HEP/vtg bioassays, whereas the antagonism was

  11. 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.

  12. 21 CFR 109.30 - Tolerances for polychlorinated biphenyls (PCB's).

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Tolerances for polychlorinated biphenyls (PCB's... Tolerances for polychlorinated biphenyls (PCB's). (a) Polychlorinated biphenyls (PCB's) are toxic, industrial... practicable time. For the purposes of this paragraph, the term “polychlorinated biphenyls (PCB's)”...

  13. Occurrence of Tn4371-related mobile elements and sequences in (chloro)biphenyl-degrading bacteria.

    Science.gov (United States)

    Springael, D; Ryngaert, A; Merlin, C; Toussaint, A; Mergeay, M

    2001-01-01

    Tn4371, a 55-kb transposable element involved in the degradation and biphenyl or 4-chlorobiphenyl identified in Ralstonia eutropha A5, displays a modular structure including a phage-like integrase gene (int), a Pseudomonas-like (chloro)biphenyl catabolic gene cluster (bph), and RP4- and Ti-plasmid-like transfer genes (trb) (C. Merlin, D. Springael, and A. Toussaint, Plasmid 41:40-54, 1999). Southern blot hybridization was used to examine the presence of different regions of Tn4371 in a collection of (chloro)biphenyl-degrading bacteria originating from different habitats and belonging to different bacterial genera. Tn4371-related sequences were never detected on endogenous plasmids. Although the gene probes containing only bph sequences hybridized to genomic DNA from most strains tested, a limited selection of strains, all beta-proteobacteria, displayed hybridization patterns similar to the Tn4371 bph cluster. Homology between Tn4371 and DNA of two of those strains, originating from the same area as strain A5, extended outside the catabolic genes and covered the putative transfer region of Tn4371. On the other hand, none of the (chloro)biphenyl degraders hybridized with the outer left part of Tn4371 containing the int gene. The bph catabolic determinant of the two strains displaying homology to the Tn4371 transfer genes and a third strain isolated from the A5 area could be mobilized to a R. eutropha recipient, after insertion into an endogenous or introduced IncP1 plasmid. The mobilized DNA of those strains included all Tn4371 homologous sequences previously identified in their genome. Our observations show that the bph genes present on Tn4371 are highly conserved between different (chloro)biphenyl-degrading hosts, isolated globally but belonging mainly to the beta-proteobacteria. On the other hand, Tn4371-related mobile elements carrying bph genes are apparently only found in isolates from the environment that provided the Tn4371-bearing isolate A5.

  14. Induction of 9-cis-epoxycarotenoid dioxygenase in Arabidopsis thaliana seeds enhances seed dormancy.

    Science.gov (United States)

    Martínez-Andújar, Cristina; Ordiz, M Isabel; Huang, Zhonglian; Nonogaki, Mariko; Beachy, Roger N; Nonogaki, Hiroyuki

    2011-10-11

    Full understanding of mechanisms that control seed dormancy and germination remains elusive. Whereas it has been proposed that translational control plays a predominant role in germination, other studies suggest the importance of specific gene expression patterns in imbibed seeds. Transgenic plants were developed to permit conditional expression of a gene encoding 9-cis-epoxycarotenoid dioxygenase 6 (NCED6), a rate-limiting enzyme in abscisic acid (ABA) biosynthesis, using the ecdysone receptor-based plant gene switch system and the ligand methoxyfenozide. Induction of NCED6 during imbibition increased ABA levels more than 20-fold and was sufficient to prevent seed germination. Germination suppression was prevented by fluridone, an inhibitor of ABA biosynthesis. In another study, induction of the NCED6 gene in transgenic seeds of nondormant mutants tt3 and tt4 reestablished seed dormancy. Furthermore, inducing expression of NCED6 during seed development suppressed vivipary, precocious germination of developing seeds. These results indicate that expression of a hormone metabolism gene in seeds can be a sole determinant of dormancy. This study opens the possibility of developing a robust technology to suppress or promote seed germination through engineering pathways of hormone metabolism.

  15. An ancient relative of cyclooxygenase in cyanobacteria is a linoleate 10S-dioxygenase that works in tandem with a catalase-related protein with specific 10S-hydroperoxide lyase activity.

    Science.gov (United States)

    Brash, Alan R; Niraula, Narayan P; Boeglin, William E; Mashhadi, Zahra

    2014-05-09

    In the course of exploring the scope of catalase-related hemoprotein reactivity toward fatty acid hydroperoxides, we detected a novel candidate in the cyanobacterium Nostoc punctiforme PCC 73102. The immediate neighboring upstream gene, annotated as "cyclooxygenase-2," appeared to be a potential fatty acid heme dioxygenase. We cloned both genes and expressed the cDNAs in Escherichia coli, confirming their hemoprotein character. Oxygen electrode recordings demonstrated a rapid (>100 turnovers/s) reaction of the heme dioxygenase with oleic and linoleic acids. HPLC, including chiral column analysis, UV, and GC-MS of the oxygenated products, identified a novel 10S-dioxygenase activity. The catalase-related hemoprotein reacted rapidly and specifically with linoleate 10S-hydroperoxide (>2,500 turnovers/s) with a hydroperoxide lyase activity specific for the 10S-hydroperoxy enantiomer. The products were identified by NMR as (8E)10-oxo-decenoic acid and the C8 fragments, 1-octen-3-ol and 2Z-octen-1-ol, in ∼3:1 ratio. Chiral HPLC analysis established strict enzymatic control in formation of the 3R alcohol configuration (99% enantiomeric excess) and contrasted with racemic 1-octen-3-ol formed in reaction of linoleate 10S-hydroperoxide with hematin or ferrous ions. The Nostoc linoleate 10S-dioxygenase, the sequence of which contains the signature catalytic sequence of cyclooxygenases and fungal linoleate dioxygenases (YRWH), appears to be a heme dioxygenase ancestor. The novel activity of the lyase expands the known reactions of catalase-related proteins and functions in Nostoc in specific transformation of the 10S-hydroperoxylinoleate.

  16. Promotion of Germination Using Hydroxamic Acid Inhibitors of 9-cis-Epoxycarotenoid Dioxygenase

    Science.gov (United States)

    Awan, Sajjad Z.; Chandler, Jake O.; Harrison, Peter J.; Sergeant, Martin J.; Bugg, Timothy D. H.; Thompson, Andrew J.

    2017-01-01

    Abscisic acid (ABA) inhibits seed germination and the regulation of ABA biosynthesis has a role in maintenance of seed dormancy. The key rate-limiting step in ABA biosynthesis is catalyzed by 9-cis-epoxycarotenoid dioxygenase (NCED). Two hydroxamic acid inhibitors of carotenoid cleavage dioxygenase (CCD), D4 and D7, previously found to inhibit CCD and NCED in vitro, are shown to have the novel property of decreasing mean germination time of tomato (Solanum lycopersicum L.) seeds constitutively overexpressing LeNCED1. Post-germination, D4 exhibited no negative effects on tomato seedling growth in terms of height, dry weight, and fresh weight. Tobacco (Nicotiana tabacum L.) seeds containing a tetracycline-inducible LeNCED1 transgene were used to show that germination could be negatively and positively controlled through the chemical induction of gene expression and the chemical inhibition of the NCED protein: application of tetracycline increased mean germination time and delayed hypocotyl emergence in a similar manner to that observed when exogenous ABA was applied and this was reversed by D4 when NCED expression was induced at intermediate levels. D4 also improved germination in lettuce (Lactuca sativa L.) seeds under thermoinhibitory temperatures and in tomato seeds imbibed in high osmolarity solutions of polyethylene glycol. D4 reduced ABA and dihydrophaseic acid accumulation in tomato seeds overexpressing LeNCED1 and reduced ABA accumulation in wild type tomato seeds imbibed on polyethylene glycol. The evidence supports a mode of action of D4 through NCED inhibition, and this molecule provides a lead compound for the design of NCED inhibitors with greater specificity and potency.

  17. 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.

  18. 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.

  19. Phytoalexins of the Pyrinae: Biphenyls and dibenzofurans

    OpenAIRE

    Cornelia Chizzali; Ludger Beerhues

    2012-01-01

    Biphenyls and dibenzofurans are the phytoalexins of the Pyrinae, a subtribe of the plant family Rosaceae. The Pyrinae correspond to the long-recognized Maloideae. Economically valuable species of the Pyrinae are apples and pears. Biphenyls and dibenzofurans are formed de novo in response to infection by bacterial and fungal pathogens. The inducible defense compounds were also produced in cell suspension cultures after treatment with biotic and abiotic elicitors. The antimicrobial activity of ...

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

    Science.gov (United States)

    Müller, R; Schmitt, S; Lingens, F

    1982-07-01

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

  1. Analysis of multi-domain hypothetical proteins containing iron-sulphur clusters and fad ligands reveal rieske dioxygenase activity suggesting their plausible roles in bioremediation.

    Science.gov (United States)

    Sathyanarayanan, Nitish; Nagendra, Holenarasipur Gundurao

    2012-01-01

    'Conserved hypothetical' proteins pose a challenge not just for functional genomics, but also to biology in general. As long as there are hundreds of conserved proteins with unknown function in model organisms such as Escherichia coli, Bacillus subtilis or Saccharomyces cerevisiae, any discussion towards a 'complete' understanding of these biological systems will remain a wishful thinking. Insilico approaches exhibit great promise towards attempts that enable appreciating the plausible roles of these hypothetical proteins. Among the majority of genomic proteins, two-thirds in unicellular organisms and more than 80% in metazoa, are multi-domain proteins, created as a result of gene duplication events. Aromatic ring-hydroxylating dioxygenases, also called Rieske dioxygenases (RDOs), are class of multi-domain proteins that catalyze the initial step in microbial aerobic degradation of many aromatic compounds. Investigations here address the computational characterization of hypothetical proteins containing Ferredoxin and Flavodoxin signatures. Consensus sequence of each class of oxidoreductase was obtained by a phylogenetic analysis, involving clustering methods based on evolutionary relationship. A synthetic sequence was developed by combining the consensus, which was used as the basis to search for their homologs via BLAST. The exercise yielded 129 multidomain hypothetical proteins containing both 2Fe-2S (Ferredoxin) and FNR (Flavodoxin) domains. In the current study, 40 proteins with N-terminus 2Fe-2S domain and C-terminus FNR domain are characterized, through homology modelling and docking exercises which suggest dioxygenase activity indicating their plausible roles in degradation of aromatic moieties.

  2. 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.

  3. Expression and post-translational modification of human 4-hydroxy-phenylpyruvate dioxygenase.

    Science.gov (United States)

    Aarenstrup, Lene; Falch, Anne Marie; Jakobsen, Kirsten K; Neve, Søren; Henriksen L, Linda Ø; Tommerup, Niels; Leffers, Henrik; Kristiansen, Karsten

    2002-01-01

    4-hydroxyphenylpyruvate dioxygenase (HPD) (EC 1.13.11.27) is a key enzyme involved in tyrosine catabolism. Congenital HPD deficiency is a rare, relatively benign condition known as hereditary type III tyrosinemia. The severe type I tyrosinemia, caused by a deficiency of fumarylacetoacetate hydrolase which functions downstream of HPD in the tyrosine degradation pathway, is often associated with decreased expression of HPD, and interestingly, inhibition of HPD activity seems to ameliorate the clinical symptoms of type I tyrosinemia. The HPD gene was previously mapped to the chromosomal region 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 271bp 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 provided evidence that HPD is subject to phosphorylation, and furthermore, allowed mapping of the HPD protein in the human keratinocyte 2D database.

  4. Alternative primer sets for PCR detection of genotypes involved in bacterial aerobic BTEX degradation : Distribution of the genes in BTEX degrading isolates and in subsurface soils of a BTEX contaminated industrial site

    NARCIS (Netherlands)

    Hendrickx, B; Junca, H; Vosahlova, J; Lindner, A; Ruegg, [No Value; Bucheli-Witschel, M; Faber, F; Egli, T; Mau, M; Schlomann, M; Brennerova, M; Brenner, [No Value; Pieper, DH; Top, EM; Dejonghe, W; Bastiaens, L; Springael, D

    2006-01-01

    Eight new primer sets were designed for PCR detection of (i) mono-oxygenase and dioxygenase gene sequences involved in initial attack of bacterial aerobic BTEX degradation and of (ii) catechol 2,3-dioxygenase gene sequences responsible for metacleavage of the aromatic ring. The new primer sets allow

  5. 40 CFR 721.5713 - Phenol - biphenyl polymer condensate (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Phenol - biphenyl polymer condensate... Specific Chemical Substances § 721.5713 Phenol - biphenyl polymer condensate (generic). (a) Chemical... as a phenol - biphenyl polymer condensate (PMN P-00-1220) is subject to reporting under this...

  6. 41 CFR 101-42.1102-2 - Polychlorinated biphenyls.

    Science.gov (United States)

    2010-07-01

    ... 41 Public Contracts and Property Management 2 2010-07-01 2010-07-01 true Polychlorinated biphenyls... Hazardous Materials and Certain Categories of Property § 101-42.1102-2 Polychlorinated biphenyls. (a) General. (1) Polychlorinated biphenyls (PCBs) are one member of a class of chlorinated aromatic...

  7. Chemical components from Aloe and their inhibition of indoleamine 2, 3-dioxygenase

    Directory of Open Access Journals (Sweden)

    Ya Nan Sun

    2017-01-01

    Abbreviation used: IDO: inhibit indoleamine 2, 3-dioxygenase, TMS: tetramethylsilane, HMQC: heteronuclear multiple quantum correlation, HMBC: heteronuclear multiple bond correlation, COSY: 1H-1H correlation spectroscopy, ESI-MS: Electrospray ionization mass spectrometry, DMSO: dimethyl sulfoxide

  8. Biodegradation of biphenyl and removal of 2-chlorobiphenyl by Pseudomonas sp. KM-04 isolated from PCBs-contaminated mine impacted soil

    Science.gov (United States)

    Nam, I.; Chon, C.; Kim, J.; Kim, Y.

    2013-12-01

    The aim of the present study is to remediate the PCBs contaminated mine soil using microcosm study. For that, the naturally occurring microorganisms are stimulated and enriched in soil itself by supplementing biphenyl as well as benzoic acid. As a result the biphenyl degrading organisms are induced to degrade the PCBs contamination. From the stimulated soil, the biphenyl degrading organisms are isolated and degraded metabolites are elucidated. Pseudomonas sp. strain KM-04 was isolated from PCBs-contaminated soil in a coal mine-impacted area, and identification of bacteria was done by sequencing the 16S rRNA gene analysis. The growth of Pseudomonas sp. strain KM-04 using biphenyl as the sole carbon source was investigated by culturing in 100-mL Erlenmeyer flasks containing 10 ml sterilized MSM and 10 μg/ml biphenyl, and the ability of KM-04 to remove biphenyl and 2-chlorobiphenyl from mine soil was investigated. Metabolite formation was confirmed by liquid chromatography/atmospheric pressure chemical ionization-mass spectrometric analysis. Pseudomonas sp. strain KM-04 uses biphenyl as a sole carbon and energy source, and resting cells convert biphenyl to its metabolic intermediates, including dihydroxybiphenyl, 2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoic acid, and benzoic acid. Incubation of real soil collected from abandoned mine areas with resting cells of Pseudomonas sp. strain KM-04 for 10 days resulted in the 98.5 % of biphenyl and 82.3 % of 2-chlorobiphenyl in a slurry system. The ability of the Pseudomonas sp. strain KM-04 to bioremediate biphenyl and 2-chlorobiphenyl from abandoned mine soil was examined using soil microcosm studies under laboratory conditions. Treatment of mine soil with the Pseudomonas sp. strain KM-04 for 15 days resulted in 87.1 % reduction in biphenyl and 68.7 % in 2-chlorobiphenyl contents. The results suggest that Pseudomonas sp. strain KM-04 is a potential candidate for the biological removal of biphenyl and chlorinated derivatives

  9. Ring-hydroxylating dioxygenase (RHD) expression in a microbial community during the early response to oil pollution.

    Science.gov (United States)

    Paissé, Sandrine; Goñi-Urriza, Marisol; Stalder, Thibault; Stadler, Thibault; Budzinski, Hélène; Duran, Robert

    2012-04-01

    The early functional response of a bacterial community from the sediments of a chronically oil-polluted retention basin located at the Etang de Berre (France) was investigated just after petroleum addition. After removing hydrocarbon compounds by natural abiotic and biotic processes, the sediments were maintained in microcosms and Vic Bilh petroleum was added. The diversity and the expression of genes encoding ring-hydroxylating dioxygenases (RHD) were examined just after the petroleum addition until 14 days focussing on the first hours following the contamination. RHD gene copy numbers and diversity were maintained throughout all the incubation period; however, transcripts were detected only during the first 2 days. One dominant RHD gene, immediately and specifically expressed in response to petroleum contamination, was related to RHD gene carried by a plasmid found in Pseudomonas spp. The expression of the RHD genes was correlated with high biodegradation levels observed for low molecular weight PAHs at 7 days of incubation. The study shows that the bacterial metabolism induced just after the oil input is a key stage that could determine the bacterial community structure changes. Monitoring the expression of RHD genes, key genes involved in hydrocarbon degradation, may provide useful information for managing bioremediation processes.

  10. Updated Abraham solvation parameters for polychlorinated biphenyls

    NARCIS (Netherlands)

    van Noort, P.C.M.; Haftka, J.J.H.; Parsons, J.R.

    2010-01-01

    This study shows that the recently published polychlorinated biphenyl (PCB) Abraham solvation parameters predict PCB air−n-hexadecane and n-octanol−water partition coefficients very poorly, especially for highly ortho-chlorinated congeners. Therefore, an updated set of PCB solvation parameters was d

  11. Characterization of the fungal gibberellin desaturase as a 2-oxoglutarate-dependent dioxygenase and its utilization for enhancing plant growth.

    Science.gov (United States)

    Bhattacharya, Anjanabha; Kourmpetli, Sofia; Ward, Dennis A; Thomas, Stephen G; Gong, Fan; Powers, Stephen J; Carrera, Esther; Taylor, Benjamin; de Caceres Gonzalez, Francisco Nuñez; Tudzynski, Bettina; Phillips, Andrew L; Davey, Michael R; Hedden, Peter

    2012-10-01

    The biosynthesis of gibberellic acid (GA(3)) by the fungus Fusarium fujikuroi is catalyzed by seven enzymes encoded in a gene cluster. While four of these enzymes are characterized as cytochrome P450 monooxygenases, the nature of a fifth oxidase, GA(4) desaturase (DES), is unknown. DES converts GA(4) to GA(7) by the formation of a carbon-1,2 double bond in the penultimate step of the pathway. Here, we show by expression of the des complementary DNA in Escherichia coli that DES has the characteristics of a 2-oxoglutarate-dependent dioxygenase. Although it has low amino acid sequence homology with known 2-oxoglutarate-dependent dioxygenases, putative iron- and 2-oxoglutarate-binding residues, typical of such enzymes, are apparent in its primary sequence. A survey of sequence databases revealed that homologs of DES are widespread in the ascomycetes, although in most cases the homologs must participate in non-gibberellin (GA) pathways. Expression of des from the cauliflower mosaic virus 35S promoter in the plant species Solanum nigrum, Solanum dulcamara, and Nicotiana sylvestris resulted in substantial growth stimulation, with a 3-fold increase in height in S. dulcamara compared with controls. In S. nigrum, the height increase was accompanied by a 20-fold higher concentration of GA(3) in the growing shoots than in controls, although GA(1) content was reduced. Expression of des was also shown to partially restore growth in plants dwarfed by ectopic expression of a GA 2-oxidase (GA-deactivating) gene, consistent with GA(3) being protected from 2-oxidation. Thus, des has the potential to enable substantial growth increases, with practical implications, for example, in biomass production.

  12. 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.

  13. 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

    2015-04-01

    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.

  14. In vivo correction with recombinant adenovirus of 4-hydroxyphenylpyruvic acid dioxygenase deficiencies in strain III mice.

    Science.gov (United States)

    Kubo, S; Kiwaki, K; Awata, H; Katoh, H; Kanegae, Y; Saito, I; Yamamoto, T; Miyazaki, J; Matsuda, I; Endo, F

    1997-01-01

    Tyrosinemia type 3, caused by a genetic deficiency of 4-hydroxyphenylpyruvic acid dioxygenase (HPD) in tyrosine catabolism, is characterized by convulsion, ataxia, and mental retardation. The III mouse is a model of tyrosinemia type 3. HPD activity and protein are defective in the liver and its blood tyrosine levels are elevated, the range being between 1,100 and 1,656 microM. We constructed a recombinant adenoviral vector bearing the human HPD cDNA (AdexCAGhHPD), which is expressed under the control of a potent CAG promoter. III mice were injected with 1.0 x 10(8) to 1.0 x 10(9) pfu of AdexCAGhHPD through the tail vein. When 3.0 x 10(8) - 1.0 x 10(9) pfu were injected, blood tyrosine levels decreased within 3 hr, reached a normal range (under 300 microM), and remained at a low level for 2-6 weeks. Hepatic HPD activities also increased as early as 3 hr after the injection of 5.0 x 10(8) pfu, reached the levels comparable to the control mice in 3-7 days, and then decreased, and correlated well to blood tyrosine. Hepatic HPD expression was confirmed by Northern blot and immunoblot analyses. Histology revealed no difference (gross or microscopic) between the liver injected with AdexCAGhHPD and the control. No significant changes in blood tyrosine levels were noted after the second injection of 5.0 x 10(8) pfu of AdexCAGhHPD. Thus, the intravenous administration of the adenoviral vector bearing a foreign gene seems suitable for transient, early gene transfer into the liver.

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

    Science.gov (United States)

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

    1984-02-01

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

  16. Substrate Oxidation by Indoleamine 2,3-Dioxygenase: EVIDENCE FOR A COMMON REACTION MECHANISM.

    Science.gov (United States)

    Booth, Elizabeth S; Basran, Jaswir; Lee, Michael; Handa, Sandeep; Raven, Emma L

    2015-12-25

    The kynurenine pathway is the major route of L-tryptophan (L-Trp) catabolism in biology, leading ultimately to the formation of NAD(+). The initial and rate-limiting step of the kynurenine pathway involves oxidation of L-Trp to N-formylkynurenine. This is an O2-dependent process and catalyzed by indoleamine 2,3-dioxygenase and tryptophan 2,3-dioxygenase. More than 60 years after these dioxygenase enzymes were first isolated (Kotake, Y., and Masayama, I. (1936) Z. Physiol. Chem. 243, 237-244), the mechanism of the reaction is not established. We examined the mechanism of substrate oxidation for a series of substituted tryptophan analogues by indoleamine 2,3-dioxygenase. We observed formation of a transient intermediate, assigned as a Compound II (ferryl) species, during oxidation of L-Trp, 1-methyl-L-Trp, and a number of other substrate analogues. The data are consistent with a common reaction mechanism for indoleamine 2,3-dioxygenase-catalyzed oxidation of tryptophan and other tryptophan analogues.

  17. Electronic and thermal properties of Biphenyl molecules

    Science.gov (United States)

    Medina, F. G.; Ojeda, J. H.; Duque, C. A.; Laroze, D.

    2015-11-01

    Transport properties of a single Biphenyl molecule coupled to two contacts are studied. We characterise this system by a tight-binding Hamiltonian. Based on the non-equilibrium Green's functions technique with a Landauer-Büttiker formalism the transmission probability, current and thermoelectrical power are obtained. We show that the Biphenyl molecule may have semiconductor behavior for certain values of the electrode-molecule-electrode junctions and different values of the angle between the two rings of the molecule. In addition, the density of states (DOS) is calculated to compare the bandwidths with the profile of the transmission probability. DOS allows us to explain the asymmetric shape with respect to the molecule's Fermi energy.

  18. Molecular Transistor Based on the Biphenyl Substituents

    Directory of Open Access Journals (Sweden)

    A.G. Malashenko

    2016-11-01

    Full Text Available It was investigated the physical processes in the molecules, which have properties required in case of using as molecular switches, transistors, or other electronic elements of future computers. Studies show that in the molecules of biphenyl substituents the angle between the planes of the phenyl rings depends on the magnitude of the applied external electric field. So, the ratio of squares of cosines of the angles between the phenyl groups in the field 0.01 a.u. and without field reaches 18. It significantly changes the ability of electrons to move along the long axis of the molecule. By varying the nature of the substituents, we can obtain the molecule characteristics that make these molecules promising for future using. This effect provides the use of biphenyl substitutes as transistors in electrical circuits constructed on separate molecules.

  19. Cytosolic and plastoglobule-targeted carotenoid dioxygenases from Crocus sativus are both involved in beta-ionone release.

    Science.gov (United States)

    Rubio, Angela; Rambla, José Luís; Santaella, Marcella; Gómez, M Dolores; Orzaez, Diego; Granell, Antonio; Gómez-Gómez, Lourdes

    2008-09-05

    Saffron, the processed stigma of Crocus sativus, is characterized by the presence of several apocarotenoids that contribute to the color, flavor, and aroma of the spice. However, little is known about the synthesis of aroma compounds during the development of the C. sativus stigma. The developing stigma is nearly odorless, but before and at anthesis, the aromatic compound beta-ionone becomes the principal norisoprenoid volatile in the stigma. In this study, four carotenoid cleavage dioxygenase (CCD) genes, CsCCD1a, CsCCD1b, CsCCD4a, and CsCCD4b, were isolated from C. sativus. Expression analysis showed that CsCCD1a was constitutively expressed, CsCCD1b was unique to the stigma tissue, but only CsCCD4a and -b had expression patterns consistent with the highest levels of beta-carotene and emission of beta-ionone derived during the stigma development. The CsCCD4 enzymes were localized in plastids and more specifically were present in the plastoglobules. The enzymatic activities of CsCCD1a, CsCCD1b, and CsCCD4 enzymes were determined by Escherichia coli expression, and subsequent analysis of the volatile products was generated by GC/MS. The four CCDs fell in two phylogenetically divergent dioxygenase classes, but all could cleave beta-carotene at the 9,10(9',10') positions to yield beta-ionone. The data obtained suggest that all four C. sativus CCD enzymes may contribute in different ways to the production of beta-ionone. In addition, the location and precise timing of beta-ionone synthesis, together with its known activity as a fragrance and insect attractant, suggest that this volatile may have a role in Crocus pollination.

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

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

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

  1. Crystal Structures of Fe2+ Dioxygenase Superoxo, Alkylperoxo, and Bound Product Intermediates

    OpenAIRE

    Kovaleva, Elena G.; Lipscomb, John D.

    2007-01-01

    We report the structures of three intermediates in the O2 activation and insertion reactions of an extradiol ring-cleaving dioxygenase. A crystal of Fe2+-containing homoprotocatechuate 2,3-dioxygenase was soaked in the slow substrate 4-nitrocatechol in a low O2 atmosphere. The X-ray crystal structure shows that three different intermediates reside in different subunits of a single homotetrameric enzyme molecule. One of these is the key substrate-alkylperoxo-Fe2+ intermediate, which has been p...

  2. Enzymology of the carotenoid cleavage dioxygenases: reaction mechanisms, inhibition and biochemical roles.

    Science.gov (United States)

    Harrison, Peter J; Bugg, Timothy D H

    2014-02-15

    Carotenoid cleavage dioxygenases (CCDs) are a large family of non-heme iron (II) dependent enzymes. CCDs catalyse the selective oxidative cleavage of carotenoids to produce apocarotenoids. Apocarotenoid derived molecules form important signalling molecules in plants in the form of abscisic acid and strigolactone and in mammals in the form of retinal. Very little is known biochemically about the CCDs and only a handful of CCDs have been biochemically characterised. Mechanistically, debate surrounds whether CCDs utilise a mono or dioxygenase mechanism. Here, we review the biochemical roles of CCDs, discuss the mechanisms by which CCD cleavage is proposed to occur, and discuss recent reports of selective CCD enzyme inhibitors.

  3. Optimizing Polychlorinated Biphenyl Degradation by Flavonoid-Induced Cells of the Rhizobacterium Rhodococcus erythropolis U23A.

    Directory of Open Access Journals (Sweden)

    Thi Thanh My Pham

    Full Text Available There is evidence that many plant secondary metabolites may act as signal molecules to trigger the bacterial ability to metabolize polychlorinated biphenyls (PCBs during the rhizoremediation process. However, the bases for the PCB rhizoremediation process are still largely unknown. The rhizobacterium Rhodococcus erythropolis U23A is unable to use flavanone as a growth substrate. However, on the basis of an assay that monitors the amount of 4-chlorobenzoate produced from 4-chlorobiphenyl by cells grown co-metabolically on flavanone plus sodium acetate, this flavonoid was previously found to be a potential inducer of the U23A biphenyl catabolic pathway. In this work, and using the same assay, we identified ten other flavonoids that did not support growth, but that acted as inducers of the U23A biphenyl pathway, and we confirmed flavonoid induction of the biphenyl catabolic pathway using quantitative real-time polymerase chain reaction (RT-qPCR on the bphA gene. We also examined the effect of the growth co-substrate on flavonoid induction. Sodium acetate was replaced by glucose, mannose, sucrose, or mannitol, which are sugars found in plant root exudates. The data showed that the level of induction of strain U23A biphenyl-degrading enzymes was significantly influenced by the nature and concentration of the flavonoid in the growth medium, as well as by the substrate used for growth. Sucrose allowed for an optimal induction response for most flavonoids. Some flavonoids, such as flavone and isoflavone, were better inducers of the biphenyl catabolic enzymes than biphenyl itself. We also found that all flavonoids tested in this work were metabolized by strain U23A during co-metabolic growth, but that the metabolite profiles, as well as the level of efficiency of degradation, differed for each flavonoid. To obtain insight into how flavonoids interact with strain U23A to promote polychlorinated biphenyl (PCB degradation, we determined the concentration of

  4. Robust crop resistance to broadleaf and grass herbicides provided by aryloxyalkanoate dioxygenase transgenes.

    Science.gov (United States)

    Wright, Terry R; Shan, Guomin; Walsh, Terence A; Lira, Justin M; Cui, Cory; Song, Ping; Zhuang, Meibao; Arnold, Nicole L; Lin, Gaofeng; Yau, Kerrm; Russell, Sean M; Cicchillo, Robert M; Peterson, Mark A; Simpson, David M; Zhou, Ning; Ponsamuel, Jayakumar; Zhang, Zhanyuan

    2010-11-23

    Engineered glyphosate resistance is the most widely adopted genetically modified trait in agriculture, gaining widespread acceptance by providing a simple robust weed control system. However, extensive and sustained use of glyphosate as a sole weed control mechanism has led to field selection for glyphosate-resistant weeds and has induced significant population shifts to weeds with inherent tolerance to glyphosate. Additional weed control mechanisms that can complement glyphosate-resistant crops are, therefore, urgently needed. 2,4-dichlorophenoxyacetic acid (2,4-D) is an effective low-cost, broad-spectrum herbicide that controls many of the weeds developing resistance to glyphosate. We investigated the substrate preferences of bacterial aryloxyalkanoate dioxygenase enzymes (AADs) that can effectively degrade 2,4-D and have found that some members of this class can act on other widely used herbicides in addition to their activity on 2,4-D. AAD-1 cleaves the aryloxyphenoxypropionate family of grass-active herbicides, and AAD-12 acts on pyridyloxyacetate auxin herbicides such as triclopyr and fluroxypyr. Maize plants transformed with an AAD-1 gene showed robust crop resistance to aryloxyphenoxypropionate herbicides over four generations and were also not injured by 2,4-D applications at any growth stage. Arabidopsis plants expressing AAD-12 were resistant to 2,4-D as well as triclopyr and fluroxypyr, and transgenic soybean plants expressing AAD-12 maintained field resistance to 2,4-D over five generations. These results show that single AAD transgenes can provide simultaneous resistance to a broad repertoire of agronomically important classes of herbicides, including 2,4-D, with utility in both monocot and dicot crops. These transgenes can help preserve the productivity and environmental benefits of herbicide-resistant crops.

  5. Metabolism and metabolites of polychlorinated biphenyls.

    Science.gov (United States)

    Grimm, Fabian A; Hu, Dingfei; Kania-Korwel, Izabela; Lehmler, Hans-Joachim; Ludewig, Gabriele; Hornbuckle, Keri C; Duffel, Michael W; Bergman, Åke; Robertson, Larry W

    2015-03-01

    Abstract The metabolism of polychlorinated biphenyls (PCBs) is complex and has an impact on toxicity, and thereby on the assessment of PCB risks. A large number of reactive and stable metabolites are formed in the processes of biotransformation in biota in general, and in humans in particular. The aim of this document is to provide an overview of PCB metabolism, and to identify the metabolites of concern and their occurrence. Emphasis is given to mammalian metabolism of PCBs and their hydroxyl, methylsulfonyl, and sulfated metabolites, especially those that persist in human blood. Potential intracellular targets and health risks are also discussed.

  6. Endogenous hydrogen peroxide is a key factor in the yeast extract-induced activation of biphenyl biosynthesis in cell cultures of Sorbus aucuparia.

    Science.gov (United States)

    Qiu, Xiaofang; Lei, Caiyan; Huang, Lili; Li, Xing; Hao, He; Du, Zhigao; Wang, Hong; Ye, Hechun; Beerhues, Ludger; Liu, Benye

    2012-01-01

    Biphenyls are unique phytoalexins produced by plants belonging to Pyrinae, a subtribe of the economically important Rosaceae family. The formation of aucuparin, a well-known biphenyl, is induced by yeast extract (YE) in cell cultures of Sorbus aucuparia. However, the molecular mechanism underlying YE-induced activation of biphenyl biosynthesis remains unknown. Here we demonstrate that the addition of YE to the cell cultures results in a burst of reactive oxygen species (ROS; H(2)O(2) and O(2) (-)), followed by transcriptional activation of the biphenyl synthase 1 gene (BIS1) encoding the key enzyme of the biphenyl biosynthetic pathway and aucuparin accumulation. Pretreatment of the cell cultures with ROS scavenger dihydrolipoic acid and NADPH oxidase-specific inhibitor diphenylene iodonium abolished all of the above YE-induced biological events. However, when the cell cultures was pretreated with superoxide dismutase specific inhibitor N,N-diethyldithiocarbamic acid, although O(2) (-) continued to be generated, the H(2)O(2) accumulation, BIS1 expression and aucuparin production were blocked. Interestingly, exogenous supply of H(2)O(2) in the range of 0.05-10 mM failed to induce aucuparin accumulation. These results indicate that endogenous generation of H(2)O(2) rather than that of O(2) (-) is a key factor in YE-induced accumulation of biphenyl phytoalexins in cell cultures of S. aucuparia.

  7. Transcriptional Response of Rhodococcus aetherivorans I24 to Polychlorinated Biphenyl-Contaminated Sediments

    KAUST Repository

    Puglisi, Edoardo

    2010-04-06

    We used a microarray targeting 3,524 genes to assess the transcriptional response of the actinomycete Rhodococcus aetherivorans I24 in minimal medium supplemented with various substrates (e. g., PCBs) and in both PCB-contaminated and non-contaminated sediment slurries. Relative to the reference condition (minimal medium supplemented with glucose), 408 genes were upregulated in the various treatments. In medium and in sediment, PCBs elicited the upregulation of a common set of 100 genes, including gene-encoding chaperones (groEL), a superoxide dismutase (sodA), alkyl hydroperoxide reductase protein C (ahpC), and a catalase/peroxidase (katG). Analysis of the R. aetherivorans I24 genome sequence identified orthologs of many of the genes in the canonical biphenyl pathway, but very few of these genes were upregulated in response to PCBs or biphenyl. This study is one of the first to use microarrays to assess the transcriptional response of a soil bacterium to a pollutant under conditions that more closely resemble the natural environment. Our results indicate that the transcriptional response of R. aetherivorans I24 to PCBs, in both medium and sediment, is primarily directed towards reducing oxidative stress, rather than catabolism. © 2010 Springer Science+Business Media, LLC.

  8. Structures of aminophenol dioxygenase in complex with intermediate, product and inhibitor.

    Science.gov (United States)

    Li, De Feng; Zhang, Jia Yue; Hou, Yan Jie; Liu, Lei; Hu, Yonglin; Liu, Shuang Jiang; Wang, Da Cheng; Liu, Wei

    2013-01-01

    Dioxygen activation by nonhaem Fe(II) enzymes containing the 2-His-1-carboxylate facial triad has been extensively studied in recent years. Here, crystal structures of 2-aminophenol 1,6-dioxygenase, an enzyme that represents a minor group of extradiol dioxygenases and that catalyses the ring opening of 2-aminophenol, in complex with the lactone intermediate (4Z,6Z)-3-iminooxepin-2(3H)-one and the product 2-aminomuconic 6-semialdehyde and in complex with the suicide inhibitor 4-nitrocatechol are reported. The Fe-ligand binding schemes observed in these structures revealed some common geometrical characteristics that are shared by the published structures of extradiol dioxygenases, suggesting that enzymes that catalyse the oxidation of noncatecholic compounds are very likely to utilize a similar strategy for dioxygen activation and the fission of aromatic rings as the canonical mechanism. The Fe-ligation arrangement, however, is strikingly enantiomeric to that of all other 2-His-1-carboxylate enzymes apart from protocatechuate 4,5-dioxygenase. This structural variance leads to the generation of an uncommon O(-)-Fe(2+)-O(-) species prior to O(2) binding, which probably forms the structural basis on which APD distinguishes its specific substrate and inhibitor, which share an analogous molecular structure.

  9. 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

    4-hydroxyphenylpyruvate dioxygenase (HPD) (EC 1.13.11.27) is a key enzyme involved in tyrosine catabolism. Congenital HPD deficiency is a rare, relatively benign condition known as hereditary type III tyrosinemia. The severe type I tyrosinemia, caused by a deficiency of fumarylacetoacetate hydrol...

  10. Natural CD4+ T-cell responses against indoleamine 2,3-dioxygenase

    DEFF Research Database (Denmark)

    Munir, Shamaila; Larsen, Stine Kiaer; Iversen, Trine Zeeberg;

    2012-01-01

    The enzyme indoleamine 2,3-dioxygenase (IDO) contributes to immune tolerance in a variety of settings. In cancer IDO is expressed within the tumor itself as well as in antigen-presenting cells in tumor-draining lymph nodes, where it endorses the establishment of peripheral immune tolerance to tumor...

  11. 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...

  12. 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.

  13. 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

  14. 4-Nitrocatechol as a colorimetric probe for non-heme iron dioxygenases.

    Science.gov (United States)

    Tyson, C A

    1975-03-10

    4-Nitrocatechol is examined as an active site probe for non-heme iron dioxygenases and found to be of value, particularly with those containing iron in the Fe(II) oxidation state. 4-Nitrocatechol is astrong competitive inhibitor of substrate oxygenation by protocatechuate 3,4-dioxygenase, forming a reversible complex with this enzyme, and by pyrocatechase. The number of binding sites per enzyme molecule titrated spectrophotometrically with 4-nitrocatechol agrees with results from previous studies with either the principal substrate or other analogues, as expected of an effective probe. Despite these facts and the observation that both enzymes cleave the same substrates at the same carbon-carbon bond, the optical and electron paramagnetic resonance (EPR) spectra of their 4-nitrocatechol complexes are remarkably different. The 4-nitocatechol-protocatechuate 3,4-dioxygenase optical spectra resemble that of the 4-nitrocatecholate ion shifted 20 to 30 nm to longer wavelength. Concomitant with this change the EPR signal centered at g equal 4.28 shows increased rhombicity (g values at 4.74, 4.28, and 3.74). In contrast, the spectrum of the 4-nitrocatechol-pyrocatechase complex has a maximum at the same wavelength as that of a 1:1 solution of free Fe(II) and 4-nitrocatechol in the absence of enzyme after titration of the catecholic protons with base and the g equal 4.28 EPR signal is not resolved at liquid N-2 temperature. These changes are interpreted as resulting in part from a pronounced change in the ligand fields about the irons at the active sites which in the case of protocatechuate 3,4-dioxygenase leads to enzyme inactivation. The results also are the first indication that substrate analogues change their ionization form upon complexation with Fe (III) dioxygenases. The interaction of the probe with metapyrocatechase, an Fe(III) containing dioxygenase, and with several additional oxygenases and hydroperoxidases is also briefly examined. The probe is not specific

  15. GenBank blastx search result: AK062096 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK062096 001-044-H12 M86348.1 Pseudomonas sp. LB400 biphenyl dioxygenase (bphA), biphenyl dioxygenase (bph...E), biphenyl dioxygenase (bphF) and biphenyl dioxygenase (bphG)s, complete cds, and dihydrodiol dehydrogenase (bphB), partial cds.|BCT BCT 1e-14 +3 ...

  16. 21 CFR 509.30 - Temporary tolerances for polychlorinated biphenyls (PCB's).

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Temporary tolerances for polychlorinated biphenyls....30 Temporary tolerances for polychlorinated biphenyls (PCB's). (a) Polychlorinated biphenyls (PCB's.... (b) A compilation entitled “Analytical Methodology for Polychlorinated Biphenyls, February 1973”...

  17. 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

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

    Science.gov (United States)

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

    2016-10-02

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

  19. Bioaccumulation dynamics of polychlorinated biphenyls (PCBs) and organochlorine pesticides

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bioaccumulation dynamics of polychlorinated biphenyls (PCBs) and organochlorine pesticides was examined in young-of-the-year bluefish from seven sub-estuaries of New...

  20. 40 CFR 129.105 - Polychlorinated biphenyls (PCBs).

    Science.gov (United States)

    2010-07-01

    ... produces polychlorinated biphenyls. (2) Electrical capacitor manufacturer means a manufacturer who produces or assembles electrical capacitors in which PCB or PCB-containing compounds are part of the... are prohibited in any discharge from any PCB manufacturer. (c) Electrical capacitor...

  1. Tetraanionic biphenyl lanthanide complexes as single-molecule magnets.

    Science.gov (United States)

    Huang, Wenliang; Le Roy, Jennifer J; Khan, Saeed I; Ungur, Liviu; Murugesu, Muralee; Diaconescu, Paula L

    2015-03-02

    Inverse sandwich biphenyl complexes [(NN(TBS))Ln]2(μ-biphenyl)[K(solvent)]2 [NN(TBS) = 1,1'-fc(NSi(t)BuMe2)2; Ln = Gd, Dy, Er; solvent = Et2O, toluene; 18-crown-6], containing a quadruply reduced biphenyl ligand, were synthesized and their magnetic properties measured. One of the dysprosium biphenyl complexes was found to exhibit antiferromagnetic coupling and single-molecule-magnet behavior with Ueff of 34 K under zero applied field. The solvent coordinated to potassium affected drastically the nature of the magnetic interaction, with the other dysprosium complex showing ferromagnetic coupling. Ab initio calculations were performed to understand the nature of magnetic coupling between the two lanthanide ions bridged by the anionic arene ligand and the origin of single-molecule-magnet behavior.

  2. Spatial gradients of polychlorinated biphenyls (PCBs) and organochlorine pesticides

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Spatial gradients of polychlorinated biphenyls (PCBs) and organochlorine pesticides were examined in the young-of-the-year (YOY) blue多sh collected in the vicinity of...

  3. 77 FR 54818 - Polychlorinated Biphenyls (PCBs): Revisions to Manifesting Regulations

    Science.gov (United States)

    2012-09-06

    ... From the Federal Register Online via the Government Publishing Office ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 761 RIN 2050-AG71 Polychlorinated Biphenyls (PCBs): Revisions to Manifesting Regulations AGENCY: Environmental Protection Agency (EPA). ACTION: Direct final rule. SUMMARY:...

  4. 77 FR 54863 - Polychlorinated Biphenyls (PCBs): Revisions to Manifesting Regulations

    Science.gov (United States)

    2012-09-06

    ... From the Federal Register Online via the Government Publishing Office ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 761 ] RIN 2050-AG71 Polychlorinated Biphenyls (PCBs): Revisions to Manifesting... CFR Part 761 Environmental protection, Hazardous substances, Manifest, Polychlorinated...

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

    Science.gov (United States)

    Fielding, Andrew J.

    2014-01-01

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

  6. Whole-Cell Fluorescent Biosensors for Bioavailability and Biodegradation of Polychlorinated Biphenyls

    Directory of Open Access Journals (Sweden)

    David Ryan

    2010-02-01

    Full Text Available Whole-cell microbial biosensors are one of the newest molecular tools used in environmental monitoring. Such biosensors are constructed through fusing a reporter gene such as lux, gfp or lacZ,to a responsive promoter. There have been many reports of the applications of biosensors, particularly their use in assaying pollutant toxicity and bioavailability. This paper reviews the basic concepts behind the construction of whole-cell microbial biosensors for pollutant monitoring, and describes the applications of two such biosensors for detecting the bioavailability and biodegradation of Polychlorinated Biphenyls (PCBs.

  7. 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.

  8. 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.

  9. Molecular cloning of hyoscyamine 6 beta-hydroxylase, a 2-oxoglutarate-dependent dioxygenase, from cultured roots of Hyoscyamus niger.

    Science.gov (United States)

    Matsuda, J; Okabe, S; Hashimoto, T; Yamada, Y

    1991-05-25

    Roots of several solanaceous plants produce anticholinergic alkaloids, hyoscyamine and scopolamine. Hyoscyamine 6 beta-hydroxylase, a 2-oxoglutarate-dependent dioxygenase (EC 1.14.11.11), catalyzes hydroxylation of hyoscyamine in the biosynthetic pathway leading to scopolamine. We report here on the isolation of cDNA clones encoding the hydroxylase from a cDNA library made from mRNA of the cultured roots of Hyoscyamus niger. The library was screened with three synthetic oligonucleotides that encode amino acid sequences of internal peptide fragments of the purified hydroxylase. Nucleotide sequence analysis of the cloned cDNA revealed an open reading frame that encodes 344 amino acids (Mr = 38,999). All 12 internal peptide fragments determined in the purified enzyme were found in the amino acid sequence deduced from the cDNA. With computer-aided comparison to other proteins we found that the hydroxylase is homologous to two synthases involved in the biosynthesis of beta-lactam antibiotics in some microorganisms and the gene products of tomato pTOM13 cDNA and maize A2 locus which had been proposed to catalyze oxidative reactions in the biosynthesis of ethylene and anthocyan, respectively. RNA blotting hybridization showed that mRNA of the hydroxylase is abundant in cultured roots and present in plant roots, but absent in leaves, stems, and cultured cells of H. niger.

  10. The carotenoid cleavage dioxygenase CCD2 catalysing the synthesis of crocetin in spring crocuses and saffron is a plastidial enzyme.

    Science.gov (United States)

    Ahrazem, Oussama; Rubio-Moraga, Angela; Berman, Judit; Capell, Teresa; Christou, Paul; Zhu, Changfu; Gómez-Gómez, Lourdes

    2016-01-01

    The apocarotenoid crocetin and its glycosylated derivatives, crocins, confer the red colour to saffron. Crocetin biosynthesis in saffron is catalysed by the carotenoid cleavage dioxygenase CCD2 (AIG94929). No homologues have been identified in other plant species due to the very limited presence of crocetin and its derivatives in the plant kingdom. Spring Crocus species with yellow flowers accumulate crocins in the stigma and tepals. Four carotenoid CCDs, namely CaCCD1, CaCCD2 and CaCCD4a/b and CaCCD4c were first cloned and characterized. CaCCD2 was localized in plastids, and a longer CCD2 version, CsCCD2L, was also localized in this compartment. The activity of CaCCD2 was assessed in Escherichia coli and in a stable rice gene function characterization system, demonstrating the production of crocetin in both systems. The expression of all isolated CCDs was evaluated in stigma and tepals at three key developmental stages in relation with apocarotenoid accumulation. CaCCD2 expression parallels crocin accumulation, but C14 apocarotenoids most likely are associated to the CaCCD1 activity in Crocus ancyrensis flowers. The specific CCD2 localization and its membrane interaction will contribute to the development of a better understanding of the mechanism of crocetin biosynthesis and regulation in the chromoplast.

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

    Science.gov (United States)

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

    2014-01-01

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

  12. Dynamic changes in bacterial community structure and in naphthalene dioxygenase expression in vermicompost-amended PAH-contaminated soils.

    Science.gov (United States)

    Di Gennaro, Patrizia; Moreno, Beatriz; Annoni, Emanuele; García-Rodríguez, Sonia; Bestetti, Giuseppina; Benitez, Emilio

    2009-12-30

    The aim of the present study was to explore the potential for using vermicompost from olive-mill waste as an organic amendment for enhanced bioremediation of polycyclic aromatic hydrocarbons (PAHs)-contaminated soils. The focus was to analyse the genetic potential and the naphthalene dioxygenase (NDO) expression of the bacterial communities involved in the degradation of naphthalene, as chemical model for the degradation of PAH. The structure of the metabolically active bacterial population was evidenced in the RNA-based denaturing gradient gel electrophoresis (DGGE) profiles. The relative expression of NDO was determined with real-time PCR in both the soil and the vermicompost cDNA. Naphthalene changed the structure of the metabolically active bacterial community in the vermicompost when this was artificially contaminated. When used as amendment, naphthalene-free vermicompost modified the bacterial population in the PAH-contaminated soil, evidenced in the DGGE gels after 1 month of incubation. In the amended soil, the vermicompost enhanced the NDO enzyme expression with a concomitant biodegradation of naphthalene. The effect of the vermicompost was to induce the expression of biodegradation indicator genes in the autochthonous bacterial community and/or incorporate new bacterial species capable of degrading PAH. The results indicated that vermicompost from olive-mill wastes could be considered a suitable technology to be used in PAH bioremediation.

  13. Ring-hydroxylating dioxygenases involved in PAH biodegradation : structure, function, biodiversity

    OpenAIRE

    Jouanneau, Yves; Martin, Florence; Krivobok, Serge; Willison, John Christopher

    2011-01-01

    International audience; The first step in the biodegradation of PAHs by aerobic bacteria is catalyzed by metalloenzymes known as ring-hydroxylating dioxygenases (RHDs). Because of the hydrophobic nature and chemical resistance of PAHs, their initial attack by RHDs is a difficult reaction, which is critical to the whole degradation process. This chapter gives an overview of the current knowledge on the genetics, structure, catalytic mechanism and diversity of RHDs involved in PAH degradation. ...

  14. 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

    2013-09-01

    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.

  15. 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.

  16. Biphenyl 4-Hydroxylases Involved in Aucuparin Biosynthesis in Rowan and Apple Are Cytochrome P450 736A Proteins.

    Science.gov (United States)

    Sircar, Debabrata; Gaid, Mariam M; Chizzali, Cornelia; Reckwell, Dennis; Kaufholdt, David; Beuerle, Till; Broggini, Giovanni A L; Flachowsky, Henryk; Liu, Benye; Hänsch, Robert; Beerhues, Ludger

    2015-06-01

    Upon pathogen attack, fruit trees such as apple (Malus spp.) and pear (Pyrus spp.) accumulate biphenyl and dibenzofuran phytoalexins, with aucuparin as a major biphenyl compound. 4-Hydroxylation of the biphenyl scaffold, formed by biphenyl synthase (BIS), is catalyzed by a cytochrome P450 (CYP). The biphenyl 4-hydroxylase (B4H) coding sequence of rowan (Sorbus aucuparia) was isolated and functionally expressed in yeast (Saccharomyces cerevisiae). SaB4H was named CYP736A107. No catalytic function of CYP736 was known previously. SaB4H exhibited absolute specificity for 3-hydroxy-5-methoxybiphenyl. In rowan cell cultures treated with elicitor from the scab fungus, transient increases in the SaB4H, SaBIS, and phenylalanine ammonia lyase transcript levels preceded phytoalexin accumulation. Transient expression of a carboxyl-terminal reporter gene construct directed SaB4H to the endoplasmic reticulum. A construct lacking the amino-terminal leader and transmembrane domain caused cytoplasmic localization. Functional B4H coding sequences were also isolated from two apple (Malus × domestica) cultivars. The MdB4Hs were named CYP736A163. When stems of cv Golden Delicious were infected with the fire blight bacterium, highest MdB4H transcript levels were observed in the transition zone. In a phylogenetic tree, the three B4Hs were closest to coniferaldehyde 5-hydroxylases involved in lignin biosynthesis, suggesting a common ancestor. Coniferaldehyde and related compounds were not converted by SaB4H.

  17. Biphenyl 4-Hydroxylases Involved in Aucuparin Biosynthesis in Rowan and Apple Are Cytochrome P450 736A Proteins1[OPEN

    Science.gov (United States)

    Kaufholdt, David; Broggini, Giovanni A.L.; Flachowsky, Henryk; Hänsch, Robert

    2015-01-01

    Upon pathogen attack, fruit trees such as apple (Malus spp.) and pear (Pyrus spp.) accumulate biphenyl and dibenzofuran phytoalexins, with aucuparin as a major biphenyl compound. 4-Hydroxylation of the biphenyl scaffold, formed by biphenyl synthase (BIS), is catalyzed by a cytochrome P450 (CYP). The biphenyl 4-hydroxylase (B4H) coding sequence of rowan (Sorbus aucuparia) was isolated and functionally expressed in yeast (Saccharomyces cerevisiae). SaB4H was named CYP736A107. No catalytic function of CYP736 was known previously. SaB4H exhibited absolute specificity for 3-hydroxy-5-methoxybiphenyl. In rowan cell cultures treated with elicitor from the scab fungus, transient increases in the SaB4H, SaBIS, and phenylalanine ammonia lyase transcript levels preceded phytoalexin accumulation. Transient expression of a carboxyl-terminal reporter gene construct directed SaB4H to the endoplasmic reticulum. A construct lacking the amino-terminal leader and transmembrane domain caused cytoplasmic localization. Functional B4H coding sequences were also isolated from two apple (Malus × domestica) cultivars. The MdB4Hs were named CYP736A163. When stems of cv Golden Delicious were infected with the fire blight bacterium, highest MdB4H transcript levels were observed in the transition zone. In a phylogenetic tree, the three B4Hs were closest to coniferaldehyde 5-hydroxylases involved in lignin biosynthesis, suggesting a common ancestor. Coniferaldehyde and related compounds were not converted by SaB4H. PMID:25862456

  18. Anaerobic degradation of Polychlorinated Biphenyls (PCBs) and Polychlorinated Biphenyls Ethers (PBDEs), and microbial community dynamics of electronic waste-contaminated soil

    Energy Technology Data Exchange (ETDEWEB)

    Song, Mengke [Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Graduate University of Chinese Academy of Sciences, Beijing 100039 (China); Luo, Chunling, E-mail: clluo@gig.ac.cn [Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Li, Fangbai [Guangdong Institute of Eco-environmental and Soil Sciences, Guangzhou 510650 (China); Jiang, Longfei [Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); College of Life Sciences, Nanjing Agricultural University, Nanjing 210095 (China); Wang, Yan [Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Zhang, Dayi [Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ (United Kingdom); Zhang, Gan [Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China)

    2015-01-01

    Environmental contamination caused by electronic waste (e-waste) recycling is attracting increasing attention worldwide because of the threats posed to ecosystems and human safety. In the present study, we investigated the feasibility of in situ bioremediation of e-waste-contaminated soils. We found that, in the presence of lactate as an electron donor, higher halogenated congeners were converted to lower congeners via anaerobic halorespiration using ferrous ions in contaminated soil. The 16S rRNA gene sequences of terminal restriction fragments indicated that the three dominant strains were closely related to known dissimilatory iron-reducing bacteria (DIRB) and those able to perform dehalogenation upon respiration. The functional species performed the activities of ferrous oxidation to ferric ions and further ferrous reduction for dehalogenation. The present study links iron cycling to degradation of halogenated materials in natural e-waste-contaminated soil, and highlights the synergistic roles of soil bacteria and ferrous/ferric ion cycling in the dehalogenation of polychlorinated biphenyls (PCBs) and polybrominated biphenyl ethers (PBDEs). - Highlights: • The biodegradation PCBs and PBDEs in e-waste contaminated soils was studied. • DIRB and arylhalorespiring bacteria were responsive to dehalogenation respiration. • Soil bacteria and Fe ion cycling play synergistic roles in dehalogenation.

  19. Anaerobic degradation of polychlorinated biphenyls (PCBs) and polychlorinated biphenyls ethers (PBDEs), and microbial community dynamics of electronic waste-contaminated soil.

    Science.gov (United States)

    Song, Mengke; Luo, Chunling; Li, Fangbai; Jiang, Longfei; Wang, Yan; Zhang, Dayi; Zhang, Gan

    2015-01-01

    Environmental contamination caused by electronic waste (e-waste) recycling is attracting increasing attention worldwide because of the threats posed to ecosystems and human safety. In the present study, we investigated the feasibility of in situ bioremediation of e-waste-contaminated soils. We found that, in the presence of lactate as an electron donor, higher halogenated congeners were converted to lower congeners via anaerobic halorespiration using ferrous ions in contaminated soil. The 16S rRNA gene sequences of terminal restriction fragments indicated that the three dominant strains were closely related to known dissimilatory iron-reducing bacteria (DIRB) and those able to perform dehalogenation upon respiration. The functional species performed the activities of ferrous oxidation to ferric ions and further ferrous reduction for dehalogenation. The present study links iron cycling to degradation of halogenated materials in natural e-waste-contaminated soil, and highlights the synergistic roles of soil bacteria and ferrous/ferric ion cycling in the dehalogenation of polychlorinated biphenyls (PCBs) and polybrominated biphenyl ethers (PBDEs).

  20. Degradation of Benzene by Pseudomonas veronii 1YdBTEX2 and 1YB2 Is Catalyzed by Enzymes Encoded in Distinct Catabolism Gene Clusters

    Science.gov (United States)

    de Lima-Morales, Daiana; Chaves-Moreno, Diego; Wos-Oxley, Melissa L.; Jáuregui, Ruy; Vilchez-Vargas, Ramiro

    2015-01-01

    Pseudomonas veronii 1YdBTEX2, a benzene and toluene degrader, and Pseudomonas veronii 1YB2, a benzene degrader, have previously been shown to be key players in a benzene-contaminated site. These strains harbor unique catabolic pathways for the degradation of benzene comprising a gene cluster encoding an isopropylbenzene dioxygenase where genes encoding downstream enzymes were interrupted by stop codons. Extradiol dioxygenases were recruited from gene clusters comprising genes encoding a 2-hydroxymuconic semialdehyde dehydrogenase necessary for benzene degradation but typically absent from isopropylbenzene dioxygenase-encoding gene clusters. The benzene dihydrodiol dehydrogenase-encoding gene was not clustered with any other aromatic degradation genes, and the encoded protein was only distantly related to dehydrogenases of aromatic degradation pathways. The involvement of the different gene clusters in the degradation pathways was suggested by real-time quantitative reverse transcription PCR. PMID:26475106

  1. Structures of cyano-biphenyl liquid crystals

    Science.gov (United States)

    Chu, Yuan-Chao; Tsang, Tung; Rahimzadeh, E.; Yin, L.

    1989-01-01

    The structures of p-alkyl- p'-cyano- bicyclohexanes, C(n)H(2n+1) (C6H10)(C6H10) CN (n-CCH), and p-alkyl- p'-cyano- biphenyls, C(n)H(2n+1) (C6H4)(C6H4) CN (n-CBP), were studied. It is convenient to use an x ray image intensification device to search for symmetric x ray diffraction patterns. Despite the similarities in molecular structures of these compounds, very different crystal structures were found. For the smectic phase of 2CCH, the structure is close to rhombohedral with threefold symmetry. In contrast, the structure is close to hexagonal close-packed with two molecules per unit cell for 4CCH. Since intermolecular forces may be quite weak for these liquid crystals systems, it appears that crystal structures change considerably when the alkyl chain length is slightly altered. Different structures were also found in the crystalline phase of n-CBP for n = 6 to 9. For n = 7 to 9, the structures are close to monclinic. The structures are reminiscent of the smectic-A liquid crystal structures with the linear molecules slightly tilted away from the c-axis. In contrast, the structure is quite different for n = 6 with the molecules nearly perpendicular to the c-axis.

  2. Can Stress Enhance Phytoremediation of Polychlorinated Biphenyls?

    Science.gov (United States)

    Kalinowski, Tomasz; Halden, Rolf U.

    2012-01-01

    Abstract Phytoremediation—plant-facilitated remediation of polluted soil and groundwater—is a potentially effective treatment technology for the remediation of heavy metals and certain organic compounds. However, contaminant attenuation rates are often not rapid enough to make phytoremediation a viable option when compared with alternative treatment approaches. Different strategies are being employed to enhance the efficacy of phytoremediation, including modification to the plant genome, inoculation of the rhizosphere with specialized and/or engineered bacteria, and treatment of the soil with supplementary chemicals, such as surfactants, chelators, or fertilizers. Despite these efforts, greater breakthroughs are necessary to make phytoremediation a viable technology. Here, we introduce and discuss the concept of integrating controlled environmental stresses as a strategy for enhancing phytoremediation. Plants have a diverse suite of defense mechanisms that are only induced in response to stress. Here, we examine some stress-response mechanisms in plants, focusing on defenses involving physiological changes that alter the soil microenvironment (rhizosphere), and outline how these defense mechanisms can be co-opted to enhance the effectiveness of phytoremediation of polychlorinated biphenyls and other contaminants. PMID:23236249

  3. Polychlorinated biphenyls and links to cardiovascular disease.

    Science.gov (United States)

    Perkins, Jordan T; Petriello, Michael C; Newsome, Bradley J; Hennig, Bernhard

    2016-02-01

    The pathology of cardiovascular disease is multi-faceted, with links to many modifiable and non-modifiable risk factors. Epidemiological evidence now implicates exposure to persistent organic pollutants, such as polychlorinated biphenyls (PCBs), with an increased risk of developing diabetes, hypertension, and obesity; all of which are clinically relevant to the onset and progression of cardiovascular disease. PCBs exert their cardiovascular toxicity either directly or indirectly via multiple mechanisms, which are highly dependent on the type and concentration of PCBs present. However, many PCBs may modulate cellular signaling pathways leading to common detrimental outcomes including induction of chronic oxidative stress, inflammation, and endocrine disruption. With the abundance of potential toxic pollutants increasing globally, it is critical to identify sensible means of decreasing associated disease risks. Emerging evidence now implicates a protective role of lifestyle modifications such as increased exercise and/or nutritional modulation via anti-inflammatory foods, which may help to decrease the vascular toxicity of PCBs. This review will outline the current state of knowledge linking coplanar and non-coplanar PCBs to cardiovascular disease and describe the possible molecular mechanism of this association.

  4. 75 FR 34076 - Polychlorinated Biphenyls (PCBs); Reassessment of Use Authorizations; Extension of Comment Period...

    Science.gov (United States)

    2010-06-16

    ... From the Federal Register Online via the Government Publishing Office ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 761 RIN 2070-AJ38 Polychlorinated Biphenyls (PCBs); Reassessment of Use Authorizations..., Hazardous substances, Labeling, Polychlorinated biphenyls (PCBs), Reporting and recordkeeping...

  5. Anaerobic enzyme·substrate structures provide insight into the reaction mechanism of the copper-dependent quercetin 2,3-dioxygenase

    NARCIS (Netherlands)

    Steiner, Roberto A.; Kalk, Kor H.; Dijkstra, Bauke W.

    2002-01-01

    Quercetin 2,3-dioxygenase (2,3QD) is the only firmly established copper dioxygenase known so far. Depending solely on a mononuclear Cu center, it catalyzes the breakage of the O-heterocycle of flavonols, producing more easily degradable phenolic carboxylic acid ester derivatives. In the enzymatic pr

  6. Anaerobic enzyme-substrate structures provide insight into the reaction mechanism of the copper-dependent quercetin 2,3-dioxygenase

    NARCIS (Netherlands)

    Steiner, RA; Kalk, KH; Dijkstra, BW

    2002-01-01

    Quercetin 2,3-dioxygenase (2,3QD) is the only firmly established copper dioxygenase known so far. Depending solely on a mononuclear Cu center, it catalyzes the breakage of the O-heterocycle of flavonols, producing more easily degradable phenolic carboxylic acid ester derivatives. In the enzymatic pr

  7. Identification of bacteria utilizing biphenyl, benzoate, and naphthalene in long-term contaminated soil.

    Directory of Open Access Journals (Sweden)

    Ondrej Uhlik

    Full Text Available Bacteria were identified associated with biodegradation of aromatic pollutants biphenyl, benzoate, and naphthalene in a long-term polychlorinated biphenyl- and polyaromatic hydrocarbon-contaminated soil. In order to avoid biases of culture-based approaches, stable isotope probing was applied in combination with sequence analysis of 16 S rRNA gene pyrotags amplified from (13C-enriched DNA fractions. Special attention was paid to pyrosequencing data analysis in order to eliminate the errors caused by either generation of amplicons (random errors caused by DNA polymerase, formation of chimeric sequences or sequencing itself. Therefore, sample DNA was amplified, sequenced, and analyzed along with the DNA of a mock community constructed out of 8 bacterial strains. This warranted that appropriate tools and parameters were chosen for sequence data processing. (13C-labeled metagenomes isolated after the incubation of soil samples with all three studied aromatics were largely dominated by Proteobacteria, namely sequences clustering with the genera Rhodanobacter Burkholderia, Pandoraea, Dyella as well as some Rudaea- and Skermanella-related ones. Pseudomonads were mostly labeled by (13C from naphthalene and benzoate. The results of this study show that many biphenyl/benzoate-assimilating bacteria derive carbon also from naphthalene, pointing out broader biodegradation abilities of some soil microbiota. The results also demonstrate that, in addition to traditionally isolated genera of degradative bacteria, yet-to-be cultured bacteria are important players in bioremediation. Overall, the study contributes to our understanding of biodegradation processes in contaminated soil. At the same time our results show the importance of sequencing and analyzing a mock community in order to more correctly process and analyze sequence data.

  8. Indoleamine 2,3-dioxygenases with very low catalytic activity are well conserved across kingdoms: IDOs of Basidiomycota.

    Science.gov (United States)

    Yuasa, Hajime J; Ball, Helen J

    2013-07-01

    Indoleamine 2,3-dioxygenase (IDO) is a tryptophan-degrading enzyme and is found in animals, fungi and bacteria. In fungi, its primary role is to supply nicotinamide adenine dinucleotide (NAD(+)) via the kynurenine pathway. A number of organisms possess more than one IDO gene, for example, mammals have IDO1 and IDO2 genes. We previously reported that the Pezizomycotina fungi commonly possess three types of IDO genes, IDOα, IDOβ and IDOγ. In this study, we surveyed the nature of IDO genes from Basidiomycota fungi, which are categorized into three subphyla (Agaricomycotina, Pucciniomycotina and Ustilaginomycotina). The Agaricomycotina fungi generally have three types of IDO genes (IDOa, IDOb and IDOc), which are distinct from Pezizomycotina three isozymes. Pucciniomycotina and Ustilaginomycotina species possess two types of IDO; one forms a monophyletic clade with Agaricomycotina IDOs in the phylogenetic tree, these IDOs are referred to as "typical Basidiomycota IDOs". The other is IDOγ, which showed more than 40% identity with Pezizomycotina and ciliate IDOγ. We previously demonstrated that IDO2 in mammals and IDOγ in Perzizomycotina fungi have much lower catalytic efficiencies in an in vitro assay, compared with the other IDO isoforms found in the respective species. We have developed a functional assay to determine whether particular IDO enzymes have sufficient enzymatic activity to rescue a yeast strain where IDO-deletion has rendered it auxotrophic for nicotinic acid. IDOα and IDOβ showed comparable catalytic efficiency, both of them could function in the Pezizomycotina fungal L-Trp metabolism. The catalytic efficiency and functional capacity of the Basidiomycota IDOa and IDOb were similar to Pezizomycotina IDOα/IDOβ. We found that Basidiomycota IDOc could not rescue the nicotinic acid auxotroph, similar to other IDO enzymes with low catalytic efficiency (mammalian IDO2 and most fungal IDOγ). Our study suggests that some fungal IDO enzymes function in

  9. OXIDATION OF POLYCHLORINATED BIPHENYLS BY PSEUDOMONAS SP. STRAIN LB400 AND PSEUDOMONAS PSEUDOALCALIGENES KF707

    Science.gov (United States)

    Biphenyl-grown cells and cell extracts prepared from biphenyl-grown cells of Pseudomonas sp. strain LB400 oxidize a much wider range of chlorinated biphenyls than do analogous preparations from Pseudomonas pseudoalcaligenes KF707. These results are attributed to differences in th...

  10. Exposure Monitoring and Risk Assessment of Biphenyl in the Workplace

    Directory of Open Access Journals (Sweden)

    Hyeon-Yeong Kim

    2015-05-01

    Full Text Available This study was performed to assess exposure to and the risk caused by biphenyl in the workplace. Biphenyl is widely used as a heat transfer medium and as an emulsifier and polish in industry. Vapor or high levels of dust inhalation and dermal exposure to biphenyl can cause eye inflammation, irritation of respiratory organs, and permanent lesions in the liver and nervous system. In this study, the workplace environment concentrations were assessed as central tendency exposure and reasonable maximum exposure and were shown to be 0.03 and 0.12 mg/m3, respectively. In addition, the carcinogenic risk of biphenyl as determined by risk assessment was 0.14 × 10−4 (central tendency exposure and 0.56 × 10−4 (reasonable maximum exposure, which is below the acceptable risk value of 1.0 × 10−4. Furthermore, the central tendency exposure and reasonable maximum exposure hazard quotients were 0.01 and 0.06 for oral toxicity, 0.05 and 0.23 for inhalation toxicity, and 0.08 and 0.39 for reproduction toxicity, respectively, which are all lower than the acceptable hazard quotient of 1.0. Therefore, exposure to biphenyl was found to be safe in current workplace environments. Because occupational exposure limits are based on socioeconomic assessment, they are generally higher than true values seen in toxicity experiments. Based on the results of exposure monitoring of biphenyl, the current occupational exposure limits in Korea could be reviewed.

  11. Mechanism of S-oxygenation by a cysteine dioxygenase model complex

    Science.gov (United States)

    Sastry, G. Narahari

    2012-01-01

    In this work we present the first computational study on a biomimetic cysteine dioxygenase model complex, [FeII(LN3S)]+ where LN3S is a tetradentate ligand with a bis(imino)pyridyl scaffold and a pendant arylthiolate group. The reaction mechanism of sulfur dioxygenation with O2 was examined by density functional theory (DFT) methods, and compared to results obtained for cysteine dioxygenase. The reaction proceeds via multistate reactivity patterns on competing singlet, triplet and quintet spin state surfaces. The reaction mechanism is analogous to that found for cysteine dioxygenase enzymes [Kumar, D.; Thiel, W.; de Visser, S. P. J. Am. Chem. Soc. 2011, 133, 3869–3882], hence the computations indicate that this complex can closely mimic the enzymatic process. The catalytic mechanism starts from an iron(III)-superoxo complex and the attack of the terminal oxygen atom of the superoxo group on the sulfur atom of the ligand. Subsequently, the dioxygen bond breaks to form an iron(IV)-oxo complex with a bound sulfenato group. After reorganization the second oxygen atom is transferred to the substrate to give a sulfinic acid product. An alternative mechanism involving the direct attack of dioxygen on the sulfur, without involving any iron-oxygen intermediates, was also examined. Importantly, a significant energetic preference for dioxygen coordinating to the iron center prior to attack at sulfur was discovered and serves to elucidate the function of the metal ion in the reaction process. The computational results are in good agreement with experimental observations, and the differences and similarities of the biomimetic complex and the enzymatic CDO center are highlighted. PMID:22091701

  12. 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

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

    Indian Academy of Sciences (India)

    Mallayan Palaniandavar; Marappan Velusamy; Ramasamy Mayilmurugan

    2006-11-01

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

  14. Structure of the 2, 4′-dihydroxyacetophenone dioxygenase from Alcaligenes sp. 4HAP

    Energy Technology Data Exchange (ETDEWEB)

    Keegan, R.; Lebedev, A. [RAL, Harwell Oxford, Didcot OX11 0FA (United Kingdom); Erskine, P.; Guo, J.; Wood, S. P. [UCL Division of Medicine (Royal Free Campus), Rowland Hill Street, London NW3 2PF (United Kingdom); Hopper, D. J. [Aberystwyth University, Penglais, Aberystwyth SY23 3DA Wales (United Kingdom); Rigby, S. E. J. [University of Manchester, 131 Princess Street, Manchester M1 7DN (United Kingdom); Cooper, J. B., E-mail: jon.cooper@ucl.ac.uk [UCL Division of Medicine (Royal Free Campus), Rowland Hill Street, London NW3 2PF (United Kingdom); RAL, Harwell Oxford, Didcot OX11 0FA (United Kingdom)

    2014-09-01

    The first X-ray structure of a 2, 4′-dihydroxyacetophenone dioxygenase from Alcaligenes sp. 4HAP at a resolution of 2.2 Å is reported. This structure establishes that the enzyme adopts the cupin-fold, forming compact dimers with a pronounced hydrophobic interface between the monomers. Each monomer possesses a catalytic ferrous iron that is coordinated by three histidines (76, 78 and 114) and an additional ligand which has been putatively assigned as a carbonate, although formate and acetate are possibilities. 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

  15. A synthetic model of the putative Fe(II)-iminobenzosemiquinonate intermediate in the catalytic cycle of o-aminophenol dioxygenases.

    Science.gov (United States)

    Bittner, Michael M; Lindeman, Sergey V; Fiedler, Adam T

    2012-03-28

    The oxidative ring cleavage of aromatic substrates by nonheme Fe dioxygenases is thought to involve formation of a ferrous-(substrate radical) intermediate. Here we describe the synthesis of the trigonal-bipyramdial complex Fe((Ph2)Tp)(ISQ(tBu)) (2), the first synthetic example of an iron(II) center bound to an iminobenzosemiquinonate (ISQ) radical. The unique electronic structure of this S = 3/2 complex and its one-electron oxidized derivative ([3](+)) have been established on the basis of crystallographic, spectroscopic, and computational analyses. These findings further demonstrate the viability of Fe(2+)-ISQ intermediates in the catalytic cycles of o-aminophenol dioxygenases.

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

    Science.gov (United States)

    Lin, J; Milase, R N

    2015-12-01

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

  17. Role of 9-Lipoxygenase and α-Dioxygenase Oxylipin Pathways as Modulators of Local and Systemic Defense

    Institute of Scientific and Technical Information of China (English)

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

    2012-01-01

    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.

  18. para-Nitrophenol 4-monooxygenase and hydroxyquinol 1,2-dioxygenase catalyze sequential transformation of 4-nitrocatechol in Pseudomonas sp. strain WBC-3.

    Science.gov (United States)

    Wei, Min; Zhang, Jun-Jie; Liu, Hong; Zhou, Ning-Yi

    2010-11-01

    Pseudomonas sp. strain WBC-3 utilizes para-nitrophenol (PNP) as a sole source of carbon, nitrogen and energy. PnpA (PNP 4-monooxygenase) and PnpB (para-benzoquinone reductase) were shown to be involved in the initial steps of PNP catabolism via hydroquinone. We demonstrated here that PnpA also catalyzed monooxygenation of 4-nitrocatechol (4-NC) to hydroxyquinol, probably via hydroxyquinone. It was the first time that a single-component PNP monooxygenase has been shown to catalyze this conversion. PnpG encoded by a gene located in the PNP degradation cluster was purified as a His-tagged protein and identified as a hydroxyquinol dioxygenase catalyzing a ring-cleavage reaction of hydroxyquinol. Although all the genes necessary for 4-NC metabolism seemed to be present in the PNP degradation cluster in strain WBC-3, it was unable to grow on 4-NC as a sole source of carbon, nitrogen and energy. This was apparently due to the substrate's inability to trigger the expression of genes involved in degradation. Nevertheless, strain WBC-3 could completely degrade both PNP and 4-NC when PNP was used as the inducer, demonstrating its potential in bioremediation of the environment polluted by both 4-NC and PNP.

  19. A cohort study on mortality and exposure to polychlorinated biphenyls.

    Science.gov (United States)

    Hsieh, S F; Yen, Y Y; Lan, S J; Hsieh, C C; Lee, C H; Ko, Y C

    1996-01-01

    In 1979, an outbreak of food poisoning ("Yu-Cheng") occurred in Central Taiwan, ROC, involving more than 2000 people. The event was caused by ingestion of rice oil contaminated with polychlorinated derivatives of biphenyls, dibenzofurans, and quaterphenyls. A retrospective cohort study on mortality was undertaken, and possible long-term health effects in the affected individuals were studied. The mortality experience of 1940 victims (929 males, 1011 females) between 1980 and 1991 was compared with the expected numbers, which were calculated from national and local mortality rates. By the end of 1991, 102 deaths were identified, thus producing a standardized mortality ratio (SMR) of overall mortality of 0.99 for males and 1.34 for females. Total cancer mortality was lower than in each comparison group. Mortality from liver diseases was elevated significantly (SMR = 3.22), especially during the first 3 y after the food-poisoning event (SMR = 10.76). Increased clinical severity of polychlorinated biphenyl intoxication was associated with increased mortality from all causes and from liver diseases. In summary, there was a positive association between mortality and intoxication dose, and severe polychlorinated biphenyl poisoning acutely affected mainly the liver. A continued follow-up of this cohort would be valuable in the study of long-term health effects of polychlorinated biphenyl poisoning.

  20. Polychlorinated Biphenyls: In situ Bioremediation from the Environment

    Science.gov (United States)

    Polychlorinated biphenyls (PCBs) are a group of hydrophobic and stable organic compounds consisting of 209 possible congeners. Because of their unique physico-chemical properties, PCBs were used in a wide range of industrial applications. The properties that made PCBs useful in i...

  1. Polychlorinated biphenyl exposure and deiodinase activity in young infants

    NARCIS (Netherlands)

    Soechitram, Shalini D; Berghuis, Sietske A; Visser, Theo J; Sauer, Pieter J J

    2017-01-01

    BACKGROUND: Several studies have shown effects of polychlorinated biphenyls (PCBs) on serum thyroid hormone levels in pregnant woman and their infants, while other studies did not find such effects. How PCBs might affect thyroid hormone metabolism, is still unclear. Potential mechanisms are direct i

  2. Danish emission inventory for hexachlorobenzene and polychlorinated biphenyls

    DEFF Research Database (Denmark)

    Nielsen, Ole-Kenneth; Plejdrup, Marlene Schmidt; Winther, Morten;

    This report documents the improved air emission inventories for hexachlorobenzene (HCB) and polychlorinated biphenyls (PCBs). The emission inventories now include all sources covered by the EMEP/EEA Guidebook. The completeness and accuracy of the inventories for these pollutants have been...

  3. Comparison of polychlorinated biphenyl levels across studies of human neurodevelopment

    NARCIS (Netherlands)

    Longnecker, MP; Gladen, BC; Brock, JW; Grandjean, P; Jacobson, JL; Korrick, SA; Rogan, WJ; Weisglas-Kuperus, N; Hertz-Picciotto, [No Value; Ayotte, P; Stewart, P; Winneke, G; Charles, MJ; Jacobson, SW; Dewailly, E; Boersma, ER; Altshul, LM; Heinzow, B; Pagano, JJ; Jensen, AA

    2003-01-01

    Polychlorinated biphenyls (PCBs) are persistent pollutants that are ubiquitous in the food chain, and detectable amounts are in the blood of almost every person in most populations that have been examined. Extensive evidence from animal studies shows that PCBs are neurotoxins, even at low doses. Int

  4. Functional identification of gene cluster for the aniline metabolic pathway mediated by transposable element

    Institute of Scientific and Technical Information of China (English)

    LIANG Quanfeng; Takeo Masahiro; LIN Min; CHEN Ming; XU Yuquan; ZHANG Wei; PING Shuzhen; LU Wei; SONG Xianlong; WANG Weiwei; GENG Lizhao

    2005-01-01

    A convenient and widely applicable method has been developed to clone aniline metabolic gene cluster in this study. Three positive recombinant plasmids pDA1, pDB2 and pDB11 were cloned from genomic library of aniline degradation strain AD9. The result of aniline dioxygenase (AD) activity and catechol 2,3-oxygenase (C23O) activity assay showed that pDA1 and pDB11 contain aniline dioxygenase genes and catechol 2,3-dioxygenase genes, respectively. The sequence analysis of the total 24.7-kb region revealed that this region contains 25 ORFs, of which 17 genes involve metabolism of aniline. In the gene cluster, the first five genes (tadQTA1A2B) and the subsequent gene (tadR1) were predicted to encode a multi-component aniline dioxygenase and a LysR-type regulator, respectively, while the others (tadD1C1D2C2EFGIJKL) were expected to encode meta- cleavage pathway enzymes for catechol degradation. The gene cluster was surrounded by two IS1071 sequences.

  5. The Role of Indoleamine 2,3-Dioxygenase in a Mouse Model of Neuroinflammation-Induced Depression

    NARCIS (Netherlands)

    Dobos, Nikoletta; de Vries, Erik F. J.; Kema, Ido P.; Patas, Konstantinos; Prins, Marloes; Nijholt, Ingrid M.; Dierckx, Rudi A.; Korf, Jakob; den Boer, Johan A.; Luiten, Paul G. M.; Eisel, Ulrich L. M.; Borsello, Tiziana

    2012-01-01

    Indoleamine 2,3-dioxygenase (IDO), an enzyme which is activated by pro-inflammatory cytokines, has been suggested as a potential link between neuroinflammatory processes in neurodegenerative diseases (like Alzheimer's disease) and depression. The present study aimed to determine whether neuroinflamm

  6. Identification of 11 Novel Homogentisate 1,2 Dioxygenase Variants in Alkaptonuria Patients and Establishment of a Novel LOVD-Based HGD Mutation Database.

    Science.gov (United States)

    Zatkova, Andrea; Sedlackova, Tatiana; Radvansky, Jan; Polakova, Helena; Nemethova, Martina; Aquaron, Robert; Dursun, Ismail; Usher, Jeannette L; Kadasi, Ludevit

    2012-01-01

    Enzymatic loss in alkaptonuria (AKU), an autosomal recessive disorder, is caused by mutations in the homogentisate 1,2 dioxygenase (HGD) gene, which decrease or completely inactivate the function of the HGD protein to metabolize homogentisic acid (HGA). AKU shows a very low prevalence (1:100,000-250,000) in most ethnic groups, but there are countries with much higher incidence, such as Slovakia and the Dominican Republic. In this work, we report 11 novel HGD mutations identified during analysis of 36 AKU patients and 41 family members from 27 families originating from 9 different countries, mainly from Slovakia and France. In Slovak patients, we identified two additional mutations, thus a total number of HGD mutations identified in this small country is 12. In order to record AKU-causing mutations and variants of the HGD gene, we have created a HGD mutation database that is open for future submissions and is available online ( http://hgddatabase.cvtisr.sk/ ). It is founded on the Leiden Open (source) Variation Database (LOVD) system and includes data from the original AKU database ( http://www.alkaptonuria.cib.csic.es ) and also all so far reported variants and AKU patients. Where available, HGD-haplotypes associated with the mutations are also presented. Currently, this database contains 148 unique variants, of which 115 are reported pathogenic mutations. It provides a valuable tool for information exchange in AKU research and care fields and certainly presents a useful data source for genotype-phenotype correlations and also for future clinical trials.

  7. Membrane-type 1 matrix metalloproteinase cytoplasmic tail binding protein-1 (MTCBP-1) acts as an eukaryotic aci-reductone dioxygenase (ARD) in the methionine salvage pathway.

    Science.gov (United States)

    Hirano, Wakako; Gotoh, Isamu; Uekita, Takamasa; Seiki, Motoharu

    2005-06-01

    MTCBP-1 was identified as a protein that binds the cytoplasmic tail of membrane-type 1 matrix metalloproteinase (MT1-MMP/MMP-14). Since MTCBP-1 has a putative beta-barrel structure, it is presumably a member of the recently proposed cupin superfamily that contains tremendously diverged functions of proteins in spite of their well-conserved beta-barrel structure. MTCBP-1 shows significant homology to the bacterial aci-reductone dioxygenase (ARD) in the cupin family, which is an enzyme in the methionine salvage pathway (MTA cycle). Since it is difficult to speculate the functions of cupin proteins simply based on their sequence homology, we examined whether the eukaryotic ARD homologs surely function in the methionine metabolism. Under sulfur-depleted conditions, yeast could grow when substrate of MTA cycle was provided. Disruption of the yeast ARD homolog, YMR009w gene, abolished ability of the cells to grow in this culture condition. Re-expression of either the YMR009w or MTCBP-1 gene restored the cell growth. Mutation analysis revealed that the glutamic acid residue in the beta-barrel fold and the N-terminal extension from the beta-barrel fold were found to be important for the activity to restore the growth. Thus, MTCBP-1 isolated as a binding protein for MT1-MMP was demonstrated to function as an ARD-like enzyme in the MTA cycle in yeast.

  8. DNA双加氧酶TET在中枢神经系统的研究进展%Research progress of DNA dioxygenase TET in the central nervous system

    Institute of Scientific and Technical Information of China (English)

    刘洁; 米亚静

    2015-01-01

    DNA双加氧酶TET家族是新发现的一类表观遗传修饰蛋白,能够将DNA的5-甲基胞嘧啶氧化为5-羟甲基胞嘧啶,进而调控基因的表达。多项研究显示,TET1-3在中枢神经系统表达丰富,其潜在的生物功能也被广泛关注。本文从TET蛋白结构功能概述、TET蛋白在中枢神经系统的表达及功能以及针对TET家族的基因敲除小鼠实验三方面作一综述。%DNA dioxygenase TET family is a recently discovered proteins involved epigenetic modification, which can oxidize the 5-methylcytosine of DNA into 5-hydroxymethylcytosine and thereby regulate gene expression. Accumulative studies have shown that TET1-3 was abundantly expressed in the central nervous system, and its poten-tial functions were beginning to be studied. This paper gives an overview of the structure and functions of TET, its po-tential roles in the central nervous system, and also the TET gene knockout experiments.

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

    Institute of Scientific and Technical Information of China (English)

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

    2009-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    M.Salah; Uddin

    2009-01-01

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

  11. Synthesis and bioevaluation of pyrazole-benzimidazolone hybrids as novel human 4-Hydroxyphenylpyruvate dioxygenase inhibitors.

    Science.gov (United States)

    Xu, Yu-Ling; Lin, Hong-Yan; Ruan, Xu; Yang, Sheng-Gang; Hao, Ge-Fei; Yang, Wen-Chao; Yang, Guang-Fu

    2015-03-06

    4-Hydroxyphenylpyruvate dioxygenase (HPPD), an essential enzyme in tyrosine catabolism, is an important target for treating type I tyrosinemia. Inhibition of HPPD can effectively alleviate the symptoms of type I tyrosinemia. However, only one commercial HPPD inhibitor, 2-(2-nitro-4-trifluoromethylbenzoyl) cyclohexane-1,3-dione (NTBC), has been available for clinical use so far. In the present study, a series of novel pyrazole-benzimidazolone hybrids were designed, synthesized and evaluated as potent human HPPD inhibitors. Most of the new compounds displayed significant inhibitory activity against the recombinant human HPPD. Moreover, compound 9l was identified as the most potent candidate with IC50 value of 0.021 μM against recombinant human HPPD, about 3-fold more potent than NTBC. Thus the pyrazole-benzimidazolone hybrid has great potential to be further developed for the treatment of type I tyrosinemia.

  12. Sonochemical Degradation of Polychlorinated Biphenyls in Aqueous Solution

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Polychlorinated biphenyl (PCB) is a kind of persistent and dangerous environmental pollutants. This paper presented the research result of sonochemical degradation of 2-chloro- biphenyl (2-CBP), 4-chlorobiphenyl (4-CBP) and 4,4'-dichlorobiphenyl (4,4'-CBP)in water. The ultrasonic degradation kinetics of 2-CBP, 4-CBP and 4,4'-CBP in water were found to be first-order and the degradation rate coefficients are 3.69×10-2, 3.19×10-2 and 2.06×10-2 at 25±1°C for 2-CBP, 4-CBP and 4,4'-CBP respectively. The influence of initial concentrations, reaction temperature on the ultrasonic decomposition of 2-CBP were also investigated.

  13. Quantum Transport in a Biphenyl Molecule: Effects of Magnetic Flux

    OpenAIRE

    Maiti, Santanu K.

    2009-01-01

    Electron transport properties of a biphenyl molecule are studied based on the Green's function formalism. The molecule is sandwiched between two metallic electrodes, where each benzene ring is threaded by a magnetic flux $\\phi$. The results are focused on the effects of the molecule to electrode coupling strength and the magnetic flux $\\phi$. Our numerical study shows that, for a fixed molecular coupling, the current amplitude across the bridge can be {\\em regulated} significantly just by tun...

  14. Research progress of the endocrine disrupting activities of polychlorinated biphenyls

    Institute of Scientific and Technical Information of China (English)

    ZHOU Jingming; QIN Zhanfen; CONG Lin; XU Xiaobai

    2004-01-01

    Polychlorinated biphenyls (PCBs) are global persistent organic pollutants. Almost all commercial PCBs mixtures, single PCB congener, and their metabolites possess endocrine disrupting activities. They can disrupt the estrogen/androgen system, thyroid hormone system and other endocrine systems by interfering with the synthesis, transport, storage, metabolism, and feedback regulation of hormones. The newest data related to the endocrine disrupting activities of PCBs and their mechanisms are reviewed and the research perspectives are also discussed.

  15. Polychlorinated biphenyls and risk of testicular germ cell tumors

    OpenAIRE

    McGlynn, Katherine A.; Quraishi, Sabah M.; Graubard, Barry I.; Weber, Jean-Philippe; Rubertone, Mark V; Erickson, Ralph L.

    2009-01-01

    Exposure to endocrine disrupting chemicals, such as polychlorinated biphenyls (PCBs), may alter hormonal balance and thereby, increase risk of testicular germ cell tumors (TGCT). To study the relationship of PCBs to TGCT, pre-diagnostic serum samples from 736 cases and 913 controls in the Servicemen’s Testicular Tumor Environmental and Endocrine Determinants study were analyzed. Adjusted odds ratios (OR) and 95% confidence intervals (95%CI) were estimated using logistic regression. PCB levels...

  16. Polychlorinated Biphenyl Presence in the Columbia River Corridor

    Energy Technology Data Exchange (ETDEWEB)

    R. M. Hermann

    2007-09-06

    The U. S. Department of Energy (DOE) is required by Comprehensive Environmental Response, Compensation, and Liability Act of 1980 regulations to develop a conceptual understanding of potential contaminant releases from the Hanford Site based on an evaluation of existing data and known historical practices. Polychlorinated biphenyls (PCBs) are one environmental contaminant potentially released through leaks, spills, or disposal. This document presents a summary of selected relevant existing information, including environmental studies and Hanford Site analytical data.

  17. Subculturing of a polychlorinated biphenyl-dechlorinating anaerobic enrichment on solid media

    Energy Technology Data Exchange (ETDEWEB)

    May, H.D.; Boyle, A.W.; Price, W.A. II.; Blake, C.K. (Celgene Corp., Warren, NJ (United States))

    1992-12-01

    An anaerobic culture capable of dechlorinating polychlorinated biphenyls was subcultured under strict anaerobic conditions on solid media containing sterilized river sediment. The dechlorination activity was transferred as a bacterial colony on a solid medium three times. After two transfers on solid medium, the culture was no longer methanogenic but still dechlorinated a mixture of tri- and tetrachlorobiphenyls. This demonstrates that anaerobic bacteria are responsible for the polychlorinated biphenyl dechlorination and can be grown without polychlorinated biphenyl on solid media.

  18. Biosynthesis of biphenyls and benzophenones--evolution of benzoic acid-specific type III polyketide synthases in plants.

    Science.gov (United States)

    Beerhues, Ludger; Liu, Benye

    2009-01-01

    Type III polyketide synthases (PKSs) generate a diverse array of secondary metabolites by varying the starter substrate, the number of condensation reactions, and the mechanism of ring closure. Among the starter substrates used, benzoyl-CoA is a rare starter molecule. Biphenyl synthase (BIS) and benzophenone synthase (BPS) catalyze the formation of identical linear tetraketide intermediates from benzoyl-CoA and three molecules of malonyl-CoA but use alternative intramolecular cyclization reactions to form 3,5-dihydroxybiphenyl and 2,4,6-trihydroxybenzophenone, respectively. In a phylogenetic tree, BIS and BPS group together closely, indicating that they arise from a relatively recent functional diversification of a common ancestral gene. The functionally diverse PKSs, which include BIS and BPS, and the ubiquitously distributed chalcone synthases (CHSs) form separate clusters, which originate from a gene duplication event prior to the speciation of the angiosperms. BIS is the key enzyme of biphenyl metabolism. Biphenyls and the related dibenzofurans are the phytoalexins of the Maloideae. This subfamily of the Rosaceae includes a number of economically important fruit trees, such as apple and pear. When incubated with ortho-hydroxybenzoyl (salicoyl)-CoA, BIS catalyzes a single decarboxylative condensation with malonyl-CoA to form 4-hydroxycoumarin. A well-known anticoagulant derivative of this enzymatic product is dicoumarol. Elicitor-treated cell cultures of Sorbus aucuparia also formed 4-hydroxycoumarin when fed with the N-acetylcysteamine thioester of salicylic acid (salicoyl-NAC). BPS is the key enzyme of benzophenone metabolism. Polyprenylated benzophenone derivatives with bridged polycyclic skeletons are widely distributed in the Clusiaceae (Guttiferae). Xanthones are regioselectively cyclized benzophenone derivatives. BPS was converted into a functional phenylpyrone synthase (PPS) by a single amino acid substitution in the initiation/elongation cavity. The

  19. Comparative study of putative 9-cis-epoxycarotenoid dioxygenase and abscisic acid accumulation in the responses of Sunki mandarin and Rangpur lime to water deficit.

    Science.gov (United States)

    Neves, D M; Filho, M A Coelho; Bellete, B S; Silva, M F G F; Souza, D T; Dos S Soares Filho, W; Costa, M G C; Gesteira, A S

    2013-09-01

    Abscisic acid is a plant hormone that participates in essential plant physiological processes, especially during adaptation to many environmental stresses, such as water deficit. The relationship between ABA accumulation and the expression of putative carotenoid cleavage dioxygenase (CCD) genes was investigated in the pot-cultivated leaves and roots of the 'Rangpur' lime and 'Sunki Maravilha' mandarin plants. Transpiration, stomatal resistance and leaf growth were evaluated when these genotypes were subjected to continuous water deficit. Under water deficit conditions, the 'Rangpur' lime extracts used greater amounts of water when compared to the 'Sunki Maravilha' plants, which reached the greatest stomatal resistance 5 days before 'Rangpur' lime. When subjected to water deficit, the roots and leaves of 'Sunki Maravilha' showed a progressive increase in ABA accumulation; however, in 'Rangpur' lime, alternations between high and low ABA concentrations were observed. These results suggest a retroactive feeding regulation by ABA. In 'Rangpur' lime the NCED2, NCED3 and CCD4a genes were expressed at the highest levels in the roots, and NCED5 was highly expressed in the leaves; in 'Sunki Maravilha', the NCED2 and NCED5 genes were most highly expressed in the roots, and NCED2 was most highly expressed in the leaves. However, for both genotypes, the transcription of these genes only correlated with ABA accumulation during the most severe water deficit conditions. The 'Rangpur' lime behaved as a vigorous rootstock; the leaf growth remained unaltered even when water was scarce. However, 'Sunki Maravilha' adaptation was based on the equilibrium of the response between the root and the aerial tissues due to water restriction. The use of the Sunki mandarin in combination with a scion with similar characteristics as its own, which responds to water deficit stress by accumulating ABA in the leaves, may display good drought tolerance under field conditions.

  20. Staphylococcus aureus CstB is a novel multidomain persulfide dioxygenase-sulfurtransferase involved in hydrogen sulfide detoxification

    Science.gov (United States)

    Shen, Jiangchuan; Keithly, Mary E.; Armstrong, Richard N.; Higgins, Khadine A.; Edmonds, Katherine A.; Giedroc, David P.

    2016-01-01

    Hydrogen sulfide (H2S) is both a lethal gas and an emerging gasotransmitter in humans, suggesting that cellular H2S level must be tightly regulated. CstB is encoded by the cst operon of the major human pathogen Staphylococcus aureus (S. aureus) and is under the transcriptional control of the persulfide sensor CstR and H2S. Here we show that CstB is a multifunctional Fe(II)-containing persulfide dioxygenase (PDO), analogous to the vertebrate protein ETHE1 (Ethylmalonic Encephalopathy Protein 1). Chromosomal deletion of ethe1 is fatal in vertebrates. In the presence of molecular oxygen (O2), hETHE1 oxidizes glutathione persulfide (GSSH) to generate sulfite and reduced glutathione. In contrast, CstB oxidizes major cellular low molecular weight (LMW) persulfide substrates from S. aureus, coenzyme A persulfide (CoASSH) and bacillithiol persulfide (BSSH), directly to generate thiosulfate (TS) and reduced thiols, thereby avoiding the cellular toxicity of sulfite. Both Cys201 in the N-terminal PDO domain (CstBPDO) and Cys408 in the C-terminal rhodanese domain (CstBRhod) strongly enhance the TS generating activity of CstB. CstB also possesses persulfide transferase (PT; reverse rhodanese) activity which generates TS when provided with LMW persulfides and sulfite, as well as conventional thiosulfate transferase (TST; rhodanese) activity; both activities require Cys408. CstB protects S. aureus against H2S toxicity with C201S and C408S cstB genes unable to rescue a NaHS-induced ΔcstB growth phenotype. Induction of the cst operon by NaHS reveals that functional CstB impacts the cellular TS concentrations. These data collectively suggest that CstB may have evolved to facilitate the clearance of LMW persulfides that occur upon the elevation of the level of cellular H2S and hence may have an impact on bacterial viability under H2S stress, in concert with the other enzymes encoded by the cst operon. PMID:26177047

  1. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-02-01

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

  3. Crystallization and preliminary crystallographic analysis of 2-aminophenol 1,6-dioxygenase complexed with substrate and with an inhibitor.

    Science.gov (United States)

    Li, De-Feng; Zhang, Jia-Yue; Hou, Yanjie; Liu, Lei; Liu, Shuang-Jiang; Liu, Wei

    2012-11-01

    Dioxygen activation implemented by nonhaem Fe(II) enzymes containing the 2-His-1-carboxylate facial triad has been extensively studied in recent years. Extradiol dioxygenase is the archetypal member of this superfamily and catalyzes the oxygenolytic ring opening of catechol analogues. Here, the crystallization and preliminary X-ray analysis of 2-aminophenol 1,6-dioxygenase, an enzyme representing a minor subset of extradiol dioxygenases that catalyze the fission of 2-aminophenol rather than catecholic compounds, is reported. Crystals of the holoenzyme with FeII and of complexes with the substrate 2-aminophenol and the suicide inhibitor 4-nitrocatechol were grown using the cocrystallization method under the same conditions as used for the crystallization of the apoenzyme. The crystals belonged to space group C2 and diffracted to 2.3-2.7 Å resolution; the crystal that diffracted to the highest resolution had unit-cell parameters a=270.24, b=48.39, c=108.55 Å, β=109.57°. All X-ray data sets collected from diffraction-quality crystals were suitable for structure determination.

  4. 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.

  5. Biodegradation of biphenyl and 2-chlorobiphenyl by a Pseudomonas sp. KM-04 isolated from PCBs-contaminated coal mine soil.

    Science.gov (United States)

    Nam, In-Hyun; Chon, Chul-Min; Jung, Ka-Young; Kim, Jae-Gon

    2014-07-01

    The biphenyl-degrading strain, Pseudomonas sp. KM-04, was isolated from polychlorinated biphenyls-contaminated soil sample obtained from the vicinity of a former coal mine. We herein report that strain KM-04 can use biphenyl as a sole carbon source, and resting cells convert biphenyl to its corresponding metabolic intermediates. Incubation of KM-04 with autoclaved mining-contaminated soil for 10 days in a slurry system reduced the levels of biphenyl and 2-chlorobiphenyl by 98.5 % and 82.3 %, respectively. Furthermore, treatment of a mine-soil microcosm with strain KM-04 for 15 days in a composting system under laboratory conditions reduced the levels of biphenyl and 2-chlorobiphenyl by 87.1 % and 68.7 %, respectively. These results suggest that KM-04 is a potential candidate for the biological removal of biphenyl and its chlorinated derivatives from polychlorinated biphenyl-contaminated mining areas.

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

    Science.gov (United States)

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

    2009-01-01

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

  7. Plasma polychlorinated biphenyls in residents of 91 PCB-contaminated and 108 non-contaminated dwellings

    DEFF Research Database (Denmark)

    Meyer, Harald William; Frederiksen, Marie; Göen, Thomas;

    2013-01-01

    In the1950s-1970s polychlorinated biphenyls (PCBs) were used in several countries as plasticizers in elastic sealants in buildings.......In the1950s-1970s polychlorinated biphenyls (PCBs) were used in several countries as plasticizers in elastic sealants in buildings....

  8. O-Methyltransferases involved in biphenyl and dibenzofuran biosynthesis.

    Science.gov (United States)

    Khalil, Mohammed N A; Brandt, Wolfgang; Beuerle, Till; Reckwell, Dennis; Groeneveld, Josephine; Hänsch, Robert; Gaid, Mariam M; Liu, Benye; Beerhues, Ludger

    2015-07-01

    Biphenyls and dibenzofurans are the phytoalexins of the Malinae involving apple and pear. Biosynthesis of the defence compounds includes two O-methylation reactions. cDNAs encoding the O-methyltransferase (OMT) enzymes were isolated from rowan (Sorbus aucuparia) cell cultures after treatment with an elicitor preparation from the scab-causing fungus, Venturia inaequalis. The preferred substrate for SaOMT1 was 3,5-dihydroxybiphenyl, supplied by the first pathway-specific enzyme, biphenyl synthase (BIS). 3,5-Dihydroxybiphenyl underwent a single methylation reaction in the presence of S-adenosyl-l-methionine (SAM). The second enzyme, SaOMT2, exhibited its highest affinity for noraucuparin, however the turnover rate was greater with 5-hydroxyferulic acid. Both substrates were only methylated at the meta-positioned hydroxyl group. The substrate specificities of the OMTs and the regiospecificities of their reactions were rationalized by homology modeling and substrate docking. Interaction of the substrates with SAM also took place at a position other than the sulfur group. Expression of SaOMT1, SaOMT2 and SaBIS3 was transiently induced in rowan cell cultures by the addition of the fungal elicitor. While the immediate SaOMT1 products were not detectable in elicitor-treated cell cultures, noraucuparin and noreriobofuran accumulated transiently, followed by increasing levels of the SaOMT2 products aucuparin and eriobofuran. SaOMT1, SaOMT2 and SaBIS3 were N- and C-terminally fused with the super cyan fluorescent protein and a modified yellow fluorescent protein, respectively. All the fluorescent reporter fusions were localized to the cytoplasm of Nicotiana benthamiana leaf epidermis cells. A revised biosynthetic pathway of biphenyls and dibenzofurans in the Malinae is presented.

  9. Fluorescent biphenyl derivatives of phenylalanine suitable for protein modification.

    Science.gov (United States)

    Chen, Shengxi; Fahmi, Nour Eddine; Bhattacharya, Chandrabali; Wang, Lin; Jin, Yuguang; Benkovic, Stephen J; Hecht, Sidney M

    2013-11-26

    In a recent study, we demonstrated that structurally compact fluorophores incorporated into the side chains of amino acids could be introduced into dihydrofolate reductase from Escherichia coli (ecDHFR) with minimal disruption of protein structure or function, even when the site of incorporation was within a folded region of the protein. The modified proteins could be employed for FRET measurements, providing sensitive monitors of changes in protein conformation. The very favorable results achieved in that study encouraged us to prepare additional fluorescent amino acids of potential utility for studying protein dynamics. Presently, we describe the synthesis and photophysical characterization of four positional isomers of biphenyl-phenylalanine, all of which were found to exhibit potentially useful fluorescent properties. All four phenylalanine derivatives were used to activate suppressor tRNA transcripts and incorporated into multiple positions of ecDHFR. All phenylalanine derivatives were incorporated with good efficiency into position 16 of ecDHFR and afforded modified proteins that consumed NADPH at rates up to about twice the rate measured for wild type. This phenomenon has been noted on a number of occasions previously and shown to be due to an increase in the off-rate of tetrahydrofolate from the enzyme, altering a step that is normally rate limiting. When introduced into sterically accessible position 49, the four phenylalanine derivatives afforded DHFRs having catalytic function comparable to wild type. The four phenylalanine derivatives were also introduced into position 115 of ecDHFR, which is known to be a folded region of the protein less tolerant of structural alteration. As anticipated, significant differences were noted in the catalytic efficiencies of the derived proteins. The ability of two of the sizable biphenyl-phenylalanine derivatives to be accommodated at position 115 with minimal perturbation of DHFR function is attributed to rotational

  10. Prediction of the Aqueous Solubilities of Polychlorinated Biphenyls

    Institute of Scientific and Technical Information of China (English)

    Shu Shen LIU; Shi Hai CUI; Lian Sheng WANG

    2004-01-01

    Using the molecular electronegativity distance vector descriptors derived directly from the molecular topological structures, the aqueous solubilities of polychlorinated biphenyls(PCBs)were predicted. A three-variable regression equation with correlation coefficient of 0.9739 and the root mean square errors of 0.26 was developed. The descriptors included in the equation represent three interactions between three pairs of atomic types,I.e.,atom-C=and>C=,-C=and-Cl,and-Cland-Cl.It has been proved that the aqueous solubilities of 137 PCB congeners can be accurately predicted as long as there are more than 65 calibration compounds.

  11. 21 CFR 109.15 - Use of polychlorinated biphenyls (PCB's) in establishments manufacturing food-packaging materials.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Use of polychlorinated biphenyls (PCB's) in... polychlorinated biphenyls (PCB's) in establishments manufacturing food-packaging materials. (a) Polychlorinated biphenyls (PCB's) represent a class of toxic industrial chemicals manufactured and sold under a variety...

  12. 21 CFR 509.15 - Use of polychlorinated biphenyls (PCB's) in establishments manufacturing food-packaging materials.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Use of polychlorinated biphenyls (PCB's) in... polychlorinated biphenyls (PCB's) in establishments manufacturing food-packaging materials. (a) Polychlorinated biphenyls (PCB's) represent a class of toxic industrial chemicals manufactured and sold under a variety...

  13. 21 CFR 500.45 - Use of polychlorinated biphenyls (PCB's) in the production, handling, and storage of animal feed.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Use of polychlorinated biphenyls (PCB's) in the... GENERAL Specific Administrative Rulings and Decisions § 500.45 Use of polychlorinated biphenyls (PCB's) in the production, handling, and storage of animal feed. (a) Polychlorinated biphenyls (PCB's)...

  14. Isolation and characterization of bacteria degrading polychlorinated biphenyls from transformer oil.

    Science.gov (United States)

    Rojas-Avelizapa, N G; Rodríguez-Vázquez, R; Martínez-Cruz, J; Esparza-García, F; Montes de Oca-García, A; Ríos-Leal, E; Fernández-Villagómez, G

    1999-01-01

    Polychlorinated biphenyls from transformer oil were degraded in liquid culture under aerobic conditions using a mixed bacterial culture isolated from a transformer oil sample with a high content of polychlorinated biphenyls and other hydrocarbons. Four strains were identified, three of them corresponded to genus Bacillus, the other one to Erwinia. Bacteria in the transformer oil could remove as much as 65% of polychlorinated biphenyls (88% W/V in the transformer oil). Additional data showed that the two isolated strains of B. lentus were able to grow on transformer oil and degrade polychlorinated biphenyls by 80 and 83%. Our results provide evidence that microorganisms occurring in transformer oil have the potential to degrade polychlorinated biphenyls.

  15. Nanomedicine and cancer immunotherapy: focus on indoleamine 2,3-dioxygenase inhibitors

    Science.gov (United States)

    Zulfiqar, Bilal; Mahroo, Amnah; Nasir, Kaenat; Farooq, Rai Khalid; Jalal, Nasir; Rashid, Muhammad Usman; Asghar, Kashif

    2017-01-01

    Nanomedicine application in cancer immunotherapy is currently one of the most challenging areas in cancer therapeutic intervention. Innovative solutions have been provided by nanotechnology to deliver cytotoxic agents to the cancer cells partially affecting the healthy cells of the body during the process. Nanoparticle-based drug delivery is an emerging approach to stimulate the immune responses against cancer. The inhibition of indoleamine 2,3-dioxygenase (IDO) is a pivotal area of research in cancer immunotherapy. IDO is a heme-containing immunosuppressive enzyme, which is responsible for the degradation of tryptophan while increasing the concentration of kynurenine metabolites. Various preclinical studies showed that IDO inhibition in certain diseases may result in significant therapeutic effects. Here, we provide a review of the natural and synthetic inhibitors of IDO. These inhibitors are classified according to their source, inhibitory concentrations, the chemical structure, and the mechanism of action. Tumor-targeted chemotherapy is an advanced technique and has more advantages as compared to the conventional chemotherapy. Search for more efficient and less toxic nanoparticles in conjunction with compounds to inhibit IDO is still an area of interest for several research groups worldwide, especially revealing to be an extensive and a promising area in cancer therapeutic innovations. PMID:28176942

  16. Indoleamine 2,3-dioxygenase: First evidence of expression in rainbow trout (Oncorhynchus mykiss).

    Science.gov (United States)

    Cortés, Jimena; Alvarez, Claudio; Santana, Paula; Torres, Elisa; Mercado, Luis

    2016-12-01

    The role of enzymes as active antimicrobial agents of the innate immunity in teleost fish is proposed in diverse works. Secretion of Indoleamine 2,3-dioxygenase (IDO) has been described in higher vertebrates; it degrades l-tryptophan in extracellular environments associated mainly with mucosal organs. The effect of IDO on decreasing amino acid concentration may inhibit the growth of potential pathogens. In fish the study of this molecule is still. Here we report the identification of an Onchorhyncus mykiss IDO homologue (OmIDO). IDO was cloned, sequenced, and the primary structure shows conservation of key functional sites. The constitutive expression is altered when the fish is challenged with LPS as a pathogen-associated molecular pattern (PAMPs). Up-regulation of IDO was shown preferentially in the fish's mucosal cells. In order to obtain evidence of a possible regulation mechanism, an in vitro cell model was used for to show that OmIDO is induced by rIFN. These study has identified a Indoleamine 2,3-dyoxigenase in O. mykiss will contribute to expands our knowledge of the function this protein in fish immune response. These findings allow to propose the use of OmIDO as a molecular indicator of strength of the animal's immune response and wellbeing.

  17. Emerging concepts on inhibitors of indoleamine 2,3-dioxygenase in rheumatic diseases.

    Science.gov (United States)

    Filippini, P; Del Papa, N; Sambataro, D; Del Bufalo, A; Locatelli, F; Rutella, S

    2012-01-01

    The enzyme indoleamine 2,3-dioxygenase 1 (IDO1) finely regulates both innate and adaptive immune responses through the degradation of the essential amino acid tryptophan into kynurenine and other downstream metabolites, which suppress effector T-cell function and promote the differentiation of regulatory T cells. A novel role for IDO1 as a signaling molecule and a modifier of innate inflammatory responses is now emerging. In particular, IDO1 can either support or antagonize inflammation in a context- and tissuedependent manner. Studies in experimental arthritis have unravelled a previously unappreciated role for IDO in controlling B-cell activation and autoantibody production. IDO dysregulation has been documented in patients with systemic lupus erythematosus, systemic sclerosis and Sjogren's syndrome, as well as in severe sepsis and chronic kidney disease. This article summarizes the contribution of IDO to the pathophysiology of inflammatory/autoimmune disorders, and discusses whether strategies to restore metabolic equilibrium in the kynurenine pathway might be pursued in diseases states such as rheumatoid arthritis and systemic sclerosis.

  18. Inhibition of indoleamine 2,3-dioxygenase activity accelerates skin wound healing.

    Science.gov (United States)

    Ito, Hiroyasu; Ando, Tatsuya; Ogiso, Hideyuki; Arioka, Yuko; Saito, Kuniaki; Seishima, Mitsuru

    2015-06-01

    Skin wound healing is a complex process involving several stages that include inflammation, proliferation, and remodeling. In the inflammatory phase, pro-inflammatory cytokines and chemokines are induced at the wound site and, they contribute to the development of wound healing. These cytokines also induce indoleamine 2,3-dioxygenase (IDO1) activity; this is the rate-limiting and first enzyme in the l-tryptophan (TRP)-l-kynurenine (KYN) pathway. This study examined the effect of IDO1 on the process of skin wound healing. The expression of the Ido1 mRNA was enhanced after creating a wound in wild-type (WT) mice. TRP concentration was simultaneously reduced at the wound site. The rate of wound healing in IDO1 knockout (IDO-KO) mice was significantly higher than that in WT mice. 1-Methyl-dl-tryptophan (1-MT), a potent inhibitor of IDO1, increased the rate of wound healing in WT mice. The administration of TRP accelerated wound healing in vivo and in an in vitro experimental model, whereas the rate of wound healing was not affected by the administration of KYN. The present study identifies the role of IDO1 in skin wound healing, and indicates that the local administration of 1-MT or TRP may provide an effective strategy for accelerating wound healing.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1984-03-01

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

  20. Inhibition of Indoleamine-2,3-dioxygenase (IDO in Glioblastoma Cells by Oncolytic Herpes Simplex Virus

    Directory of Open Access Journals (Sweden)

    Bonnie Reinhart

    2012-01-01

    Full Text Available Successful oncolytic virus treatment of malignant glioblastoma multiforme depends on widespread tumor-specific lytic virus replication and escape from mitigating innate immune responses to infection. Here we characterize a new HSV vector, JD0G, that is deleted for ICP0 and the joint sequences separating the unique long and short elements of the viral genome. We observed that JD0G replication was enhanced in certain glioblastoma cell lines compared to HEL cells, suggesting that a vector backbone deleted for ICP0 may be useful for treatment of glioblastoma. The innate immune response to virus infection can potentially impede oncolytic vector replication in human tumors. Indoleamine-2,3-dioxygenase (IDO is expressed in response to interferon γ (IFNγ and has been linked to both antiviral functions and to the immune escape of tumor cells. We observed that IFNγ treatment of human glioblastoma cells induced the expression of IDO and that this expression was quelled by infection with both wild-type and JD0G viruses. The role of IDO in inhibiting virus replication and the connection of this protein to the escape of tumor cells from immune surveillance suggest that IDO downregulation by HSV infection may enhance the oncolytic activity of vectors such as JD0G.

  1. Reaction mechanism of cobalt-substituted homoprotocatechuate 2,3-dioxygenase: a QM/MM study.

    Science.gov (United States)

    Cao, Lili; Dong, Geng; Lai, Wenzhen

    2015-04-01

    The reaction mechanisms of cobalt-substituted homoprotocatechuate 2,3-dioxygenase (Co-HPCD) with electron-rich substrate homoprotocatechuate (HPCA) and electron-poor substrate 4-nitrocatechol (4NC) were investigated by quantum mechanical/molecular mechanical (QM/MM) calculations. Our results demonstrated that the Co-O2 adducts has doublet ground state with a Co(III)-O2(•-) character when 4NC was used as the substrate, in good agreement with the EPR spectroscopic experiment. The reactive oxygen species is the doublet Co(III)-O2(•-) for Co-HPCD/4NC and the quartet SQ(•↑)-Co(II)-O2(•-↓) species for Co-HPCD/HPCA, indicating that the substrate plays important roles in the dioxygen activation by Co-HPCD. B3LYP was found to overestimate the rate-limiting barriers in Co-HPCD. TPSSh predicts barriers of 21.5 versus 12.0 kcal/mol for Co-HPCD/4NC versus Co-HPCD/HPCA, which is consistent with the fact that the rate of the reaction is decreased when the substrate was changed from HPCA to 4NC.

  2. Novel bacterial bioassay for a high-throughput screening of 4-hydroxyphenylpyruvate dioxygenase inhibitors.

    Science.gov (United States)

    Rocaboy-Faquet, Emilie; Noguer, Thierry; Romdhane, Sana; Bertrand, Cédric; Dayan, Franck Emmanuel; Barthelmebs, Lise

    2014-08-01

    Plant 4-hydroxyphenylpyruvate dioxygenase (HPPD) is the molecular target of a range of synthetic β-triketone herbicides that are currently used commercially. Their mode of action is based on an irreversible inhibition of HPPD. Therefore, this inhibitory capacity was used to develop a whole-cell colorimetric bioassay with a recombinant Escherichia coli expressing a plant HPPD for the herbicide analysis of β-triketones. The principle of the bioassay is based on the ability of the recombinant E. coli clone to produce a soluble melanin-like pigment, from tyrosine catabolism through p-hydroxyphenylpyruvate and homogentisate. The addition of sulcotrione, a HPPD inhibitor, decreased the pigment production. With the aim to optimize the assay, the E. coli recombinant clone was immobilized in sol-gel or agarose matrix in a 96-well microplate format. The limit of detection for mesotrione, tembotrione, sulcotrione, and leptospermone was 0.069, 0.051, 0.038, and 20 μM, respectively, allowing to validate the whole-cell colorimetric bioassay as a simple and cost-effective alternative tool for laboratory use. The bioassay results from sulcotrione-spiked soil samples were confirmed with high-performance liquid chromatography.

  3. Exposition of dermatophyte Trichophyton mentagrophytes to L-cystine induces expression and activation of cysteine dioxygenase.

    Science.gov (United States)

    Kasperova, Alena; Cahlikova, Romana; Kunert, Jiri; Sebela, Marek; Novak, Zdenek; Raska, Milan

    2014-11-01

    Cysteine dioxygenase (CDO) is involved in regulation of intracellular cysteine levels by catabolising the cysteine to sulphite and sulphate. In keratinolytic fungi, sulphite is actively excreted to reduce disulphide bridges in keratin before its enzymatic degradation. The pathogenicity role of CDO was confirmed in cysteine-hypersensitive and growth-defective ΔCdo mutant of Arthroderma benhamiae on hair and nails. We analysed the CDO expression regulation in T. mentagrophytes (anamorph of A. benhamiae) mycelia by determining the Cdo mRNA and CDO protein levels and by analysing the proportion of two molecular forms of CDO in response to l-cystine exposure. Cdo mRNA levels in mycelia lysates were detected by reverse-transcription real-time polymerase chain reaction and CDO protein by western blot using mouse CDO-specific hyperimmune serum. The Cdo mRNA level increased gradually 2.5-4.5 h after exposure of the mycelium to l-cystine. The CDO protein, detected as two bands of different mobility, appeared earlier in comparison to mRNA (1 h) and culminated after 24 h. More mobile form prevailed after 4.5 h. The comparison of the dynamics in the Cdo mRNA and CDO protein levels indicates that T. mentagrophytes responds to l-cystine by increased transcription and apparently decreased degradation of the CDO and by changing towards higher mobility molecular form, similar to previous reports describing mammalian analogue.

  4. Salmonella overcomes tumor immune tolerance by inhibition of tumor indoleamine 2, 3-dioxygenase 1 expression.

    Science.gov (United States)

    Kuan, Yu-Diao; Lee, Che-Hsin

    2016-01-05

    Over the past decades, Salmonella has been proven capable of inhibiting tumor growth. It can specifically target tumors and due to its facultative anaerobic property, can be more penetrative than other drug therapies. However, the molecular mechanism by which Salmonella inhibits tumor growth is still incompletely known. The antitumor therapeutic effect mediated by Salmonella is associated with an inflammatory immune response at the tumor site and a T cell-dependent immune response. Many tumors have been proven to have a high expression of indoleamine 2, 3-dioxygenase 1 (IDO), which is a rate-limiting enzyme that catalyzes tryptophan to kynurenine, thus causing immune tolerance within the tumor microenvironment. With decreased expression of IDO, increased immune response can be observed, which might be helpful when developing cancer immunotherapy. The expression of IDO was decreased after tumor cells were infected with Salmonella. In addition, Western blot analysis showed that the expression levels of phospho-protein kinase B (P-AKT), phospho-mammalian targets of rapamycin (P-mTOR), and phospho-p70 ribosomal s6 kinase (P-p70s6K) in tumor cells were decreased after Salmonella infection. In conclusion, our results indicate that Salmonella inhibits IDO expression and plays a crucial role in anti-tumor therapy, which might be a promising strategy combined with other cancer treatments.

  5. Negative Impact of Hypoxia on Tryptophan 2,3-Dioxygenase Function

    Directory of Open Access Journals (Sweden)

    Frank Elbers

    2016-01-01

    Full Text Available Tryptophan is an essential amino acid for hosts and pathogens. The liver enzyme tryptophan 2,3-dioxygenase (TDO provokes, by its ability to degrade tryptophan to N-formylkynurenine, the precursor of the immune-relevant kynurenines, direct and indirect antimicrobial and immunoregulatory states. Up to now these TDO-mediated broad-spectrum effector functions have never been observed under hypoxia in vitro, although physiologic oxygen concentrations in liver tissue are low, especially in case of infection. Here we analysed recombinant expressed human TDO and ex vivo murine TDO functions under different oxygen conditions and show that TDO-induced restrictions of clinically relevant pathogens (bacteria, parasites and of T cell proliferation are abrogated under hypoxic conditions. We pinpointed the loss of TDO efficiency to the reduction of TDO activity, since cell survival and TDO protein levels were unaffected. In conclusion, the potent antimicrobial as well as immunoregulatory effects of TDO were substantially impaired under hypoxic conditions that pathophysiologically occur in vivo. This might be detrimental for the appropriate host immune response towards relevant pathogens.

  6. Tryptophan-2,3-dioxygenase (TDO) inhibition ameliorates neurodegeneration by modulation of kynurenine pathway metabolites

    Science.gov (United States)

    Breda, Carlo; Sathyasaikumar, Korrapati V.; Sograte Idrissi, Shama; Notarangelo, Francesca M.; Estranero, Jasper G.; Moore, Gareth G. L.; Green, Edward W.; Kyriacou, Charalambos P.; Schwarcz, Robert; Giorgini, Flaviano

    2016-01-01

    Metabolites of the kynurenine pathway (KP) of tryptophan (TRP) degradation have been closely linked to the pathogenesis of several neurodegenerative disorders. Recent work has highlighted the therapeutic potential of inhibiting two critical regulatory enzymes in this pathway—kynurenine-3-monooxygenase (KMO) and tryptophan-2,3-dioxygenase (TDO). Much evidence indicates that the efficacy of KMO inhibition arises from normalizing an imbalance between neurotoxic [3-hydroxykynurenine (3-HK); quinolinic acid (QUIN)] and neuroprotective [kynurenic acid (KYNA)] KP metabolites. However, it is not clear if TDO inhibition is protective via a similar mechanism or if this is instead due to increased levels of TRP—the substrate of TDO. Here, we find that increased levels of KYNA relative to 3-HK are likely central to the protection conferred by TDO inhibition in a fruit fly model of Huntington’s disease and that TRP treatment strongly reduces neurodegeneration by shifting KP flux toward KYNA synthesis. In fly models of Alzheimer’s and Parkinson’s disease, we provide genetic evidence that inhibition of TDO or KMO improves locomotor performance and ameliorates shortened life span, as well as reducing neurodegeneration in Alzheimer's model flies. Critically, we find that treatment with a chemical TDO inhibitor is robustly protective in these models. Consequently, our work strongly supports targeting of the KP as a potential treatment strategy for several major neurodegenerative disorders and suggests that alterations in the levels of neuroactive KP metabolites could underlie several therapeutic benefits. PMID:27114543

  7. Tissue distribution, intracellular localization and proteolytic processing of rat 4-hydroxyphenylpyruvate dioxygenase.

    Science.gov (United States)

    Neve, Søren; Aarenstrup, Lene; Tornehave, Ditte; Rahbek-Nielsen, Henrik; Corydon, Thomas Juhl; Roepstorff, Peter; Kristiansen, Karsten

    2003-01-01

    4-hydroxyphenylpyruvate dioxygenase (HPD) is an important enzyme involved in tyrosine catabolism. HPD was shown to be identical to a protein named the F-antigen, exploited by immunologists because of its unique immunological properties. Congenital HPD deficiency is a rare, relatively benign condition known as hereditary type III tyrosinemia. Decreased expression of HPD is often observed in association with the severe type I tyrosinemia, and interestingly, inhibition of HPD activity seems to ameliorate the clinical symptoms of type I tyrosinemia. In this study we present a comprehensive analysis of tissue specific expression and intracellular localization of HPD in the rat. By combined use of in situ hybridization and immunohistochemistry we confirm previously known sites of expression in liver and kidney. In addition, we show that HPD is abundantly expressed in neurons in the cortex, cerebellum and hippocampus. By using immunoelectron microscopy and confocal laser scanning microscopy, we provide evidence that HPD contrary to earlier assumptions specifically localizes to membranes of the endoplasmic reticulum and the Golgi apparatus. Detailed mass spectrometric analyses of HPD purified from rat liver revealed N-terminal and C-terminal processing of HPD, and expression of recombinant HPD suggested that C-terminal processing enhances the enzymatic activity.

  8. 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.

  9. Antiparasitic and antiproliferative effects of indoleamine 2,3-dioxygenase enzyme expression in human fibroblasts.

    Science.gov (United States)

    Gupta, S L; Carlin, J M; Pyati, P; Dai, W; Pfefferkorn, E R; Murphy, M J

    1994-01-01

    Studies were carried out to evaluate the proposed role of indoleamine 2,3-dioxygenase (INDO) induction in the antimicrobial and antiproliferative effects of gamma interferon (IFN-gamma) in human fibroblasts. The INDO cDNA coding region was cloned in the pMEP4 expression vector, containing the metallothionein (MTII) promoter in the sense (+ve) or the antisense (-ve) orientation. Human fibroblasts (GM637) stably transfected with the sense construct expressed INDO activity after treatment with CdCl2 or ZnSO4, but cells transfected with the antisense construct did not. The growth of Chlamydia psittaci was strongly inhibited in INDO +ve cells but not in INDO -ve cells after treatment with Cd2+ or Zn2+. The inhibition correlated with the level of INDO activity induced and could be reversed by the addition of excess tryptophan to the medium. The growth of Toxoplasma gondii was also strongly inhibited in INDO +ve cells but not in INDO -ve cells after treatment with Cd2+. Expression of Cd(2+)-induced INDO activity also inhibited thymidine incorporation and led to cytotoxicity in INDO +ve cells but not in INDO -ve cells. Thus, the induction of INDO activity by IFN-gamma may be an important factor in the antimicrobial and antiproliferative effects of IFN-gamma in human fibroblasts. Images PMID:8188349

  10. 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.

  11. 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.

  12. Indoleamine 2, 3-dioxygenase (IDO) is essential for dendritic cell activation and chemotactic responsiveness to chemokines

    Institute of Scientific and Technical Information of China (English)

    Shih Ling HWANG; Nancy Pei-Yee CHUNG; Jacqueline Kwai-Yi CHAN; Chen-Lung Steve LIN

    2005-01-01

    Indoleamine 2, 3-dioxygenase (IDO) is a rate-limiting enzyme for the tryptophan catabolism. In human and murine cells, IDO inhibits antigen-specific T cell proliferation in vitro and suppresses T cell responses to fetal alloantigens during murine pregnancy. In mice, IDO expression is an inducible feature of specific subsets of dendritic cells (DCs),and is important for T cell regulatory properties. However, the effect of IDO and tryptophan deprivation on DC functions remains unknown. We report here that when tryptophan utilization was prevented by a pharmacological inhibitor of IDO, 1-methyl tryptophan (1MT), DC activation induced by pathogenic stimulus lipopolysaccharide (LPS) or inflammatory cytokine TNF-α was inhibited both phenotypically and functionally. Such an effect was less remarkable when DC was stimulated by a physiological stimulus, CD40 ligand. Tryptophan deprivation during DC activation also regulated the expression of CCR5 and CXCR4, as well as DC responsiveness to chemokines. These results suggest that tryptophan usage in the microenvironment is essential for DC maturation, and may also play a role in the regulation of DC migratory behaviors.

  13. 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.

  14. 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.

  15. Biphenyl synthase, a novel type III polyketide synthase.

    Science.gov (United States)

    Liu, B; Raeth, T; Beuerle, T; Beerhues, L

    2007-05-01

    Biphenyls and dibenzofurans are the phytoalexins of the Maloideae, a subfamily of the economically important Rosaceae. The carbon skeleton of the two classes of antimicrobial secondary metabolites is formed by biphenyl synthase (BIS). A cDNA encoding this key enzyme was cloned from yeast-extract-treated cell cultures of Sorbus aucuparia. BIS is a novel type III polyketide synthase (PKS) that shares about 60% amino acid sequence identity with other members of the enzyme superfamily. Its preferred starter substrate is benzoyl-CoA that undergoes iterative condensation with three molecules of malonyl-CoA to give 3,5-dihydroxybiphenyl via intramolecular aldol condensation. BIS did not accept CoA-linked cinnamic acids such as 4-coumaroyl-CoA. This substrate, however, was the preferential starter molecule for chalcone synthase (CHS) that was also cloned from S. aucuparia cell cultures. While BIS expression was rapidly, strongly and transiently induced by yeast extract treatment, CHS expression was not. In a phylogenetic tree, BIS grouped together closely with benzophenone synthase (BPS) that also uses benzoyl-CoA as starter molecule but cyclizes the common intermediate via intramolecular Claisen condensation. The molecular characterization of BIS thus contributes to the understanding of the functional diversity and evolution of type III PKSs.

  16. Aryl biphenyl-3-ylmethylpiperazines as 5-HT7 receptor antagonists.

    Science.gov (United States)

    Kim, Jeeyeon; Kim, Youngjae; Tae, Jinsung; Yeom, Miyoung; Moon, Bongjin; Huang, Xi-Ping; Roth, Bryan L; Lee, Kangho; Rhim, Hyewhon; Choo, Il Han; Chong, Youhoon; Keum, Gyochang; Nam, Ghilsoo; Choo, Hyunah

    2013-11-01

    The 5-HT7 receptor (5-HT7 R) is a promising therapeutic target for the treatment of depression and neuropathic pain. The 5-HT7 R antagonist SB-269970 exhibited antidepressant-like activity, whereas systemic administration of the 5-HT7 R agonist AS-19 significantly inhibited mechanical hypersensitivity and thermal hyperalgesia. In our efforts to discover selective 5-HT7 R antagonists or agonists, aryl biphenyl-3-ylmethylpiperazines were designed, synthesized, and biologically evaluated against the 5-HT7 R. Among the synthesized compounds, 1-([2'-methoxy-(1,1'-biphenyl)-3-yl]methyl)-4-(2-methoxyphenyl)piperazine (28) was the best binder to the 5-HT7 R (pKi =7.83), and its antagonistic property was confirmed by functional assays. The selectivity profile of compound 28 was also recorded for the 5-HT7 R over other serotonin receptor subtypes, such as 5-HT1 R, 5-HT2 R, 5-HT3 R, and 5-HT6 R. In a molecular modeling study, the 2-methoxyphenyl moiety attached to the piperazine ring of compound 28 was proposed to be essential for the antagonistic function.

  17. Levels of polychlorinated biphenyls in 1,4-dichlorobenzene mothballs

    Institute of Scientific and Technical Information of China (English)

    LIU Wen-bin; ZHENG Ming-hui; XING Ying; WANG Dong-sheng; ZHAO Xing-ru; GAO Li-rong

    2005-01-01

    Although polychlorinated biphenyls(PCBs) are globally recognized pollutant, an understanding of their resources as by-products in chemical industry is poorly investigated. This paper presents data from a study that was conducted in order to determine the extent of PCBs in 1,4-dichlorobenzene(p-DCB) mothballs. Total PCBs and dioxin-like PCBs were detected in five mothball samples. Total PCB concentrations ranged from 328 ng/g to 1798 ng/g, while the levels of WHO-TEQ were between 0.16 pg/g and 13 pg/g. Mean concentrations of total PCBs and WHO-TEQ in the samples were 724 ng/g and 3.2 pg/g, respectively. The highest level of PCB congeners was that of trichlorinated biphenyls(537 ng/g), which maybe due to the relatively low chlorination in the process of p-DCB production. A mechanism of the formation of PCBs from polychlorinated benzene in the presence of chlorine is also suggested. The results suggested that re-estimation on the risk of p-DCB products, especially the products for daily use such as mothballs, is expected.

  18. Fate and Complex Pathogenic Effects of Dioxins and Polychlorinated Biphenyls in Obese Subjects before and after Drastic Weight Loss

    Science.gov (United States)

    Kim, Min-Ji; Marchand, Philippe; Henegar, Corneliu; Antignac, Jean-Philippe; Alili, Rohia; Poitou, Christine; Bouillot, Jean-Luc; Basdevant, Arnaud; Le Bizec, Bruno; Barouki, Robert; Clément, Karine

    2011-01-01

    Background In humans, persistent organic pollutants (POPs) are stored primarily in adipose tissue. Their total body burden and their contribution to obesity-associated diseases remain unclear. Objectives We characterized POP total body burden and their redistribution in obese individuals before and after drastic weight loss and compared these values with a variety of molecular, biological, and clinical parameters. Methods Seventy-one obese subjects were enrolled and underwent bariatric surgery. Blood and adipose tissue samples were obtained at different times from these individuals as well as from 18 lean women. Results POP content (17 dioxins/furans and 18 polychlorinated biphenyl congeners) in different adipose tissue territories was similar, allowing us to assess total POP body burden from a single biopsy. Total POP body burden was 2 to 3 times higher in obese than in lean individuals. We also found increased expression of some POP target genes in obese adipose tissue. Drastic weight loss led to increased serum POPs and, within 6–12 months, to a significant 15% decrease in total polychlorinated biphenyl body burden. Importantly, serum POP levels were positively correlated with liver toxicity markers and lipid parameters, independently of age and body mass index. Conclusions POP content in adipose tissue and serum correlate with biological markers of obesity-related dysfunctions. Drastic weight loss leads to a redistribution of POPs and to a moderate decrease of their total body burden. PMID:21156398

  19. The different catalytic roles of the metal-binding ligands in human 4-hydroxyphenylpyruvate dioxygenase.

    Science.gov (United States)

    Huang, Chih-Wei; Liu, Hsiu-Chen; Shen, Chia-Pei; Chen, Yi-Tong; Lee, Sung-Jai; Lloyd, Matthew D; Lee, Hwei-Jen

    2016-05-01

    4-Hydroxyphenylpyruvate dioxygenase (HPPD) is a non-haem iron(II)-dependent oxygenase that catalyses the conversion of 4-hydroxyphenylpyruvate (HPP) to homogentisate (HG). In the active site, a strictly conserved 2-His-1-Glu facial triad co-ordinates the iron ready for catalysis. Substitution of these residues resulted in about a 10-fold decrease in the metal binding affinity, as measured by isothermal titration calorimetry, and a large reduction in enzyme catalytic efficiencies. The present study revealed the vital role of the ligand Glu(349) in enzyme function. Replacing this residue with alanine resulted in loss of activity. The E349G variant retained 5% activity for the coupled reaction, suggesting that co-ordinating water may be able to support activation of the trans-bound dioxygen upon substrate binding. The reaction catalysed by the H183A variant was fully uncoupled. H183A variant catalytic activity resulted in protein cleavage between Ile(267) and Ala(268) and the production of an N-terminal fragment. The H266A variant was able to produce 4-hydroxyphenylacetate (HPA), demonstrating that decarboxylation had occurred but that there was no subsequent product formation. Structural modelling of the variant enzyme with bound dioxygen revealed the rearrangement of the co-ordination environment and the dynamic behaviour of bound dioxygen in the H266A and H183A variants respectively. These models suggest that the residues regulate the geometry of the reactive oxygen intermediate during the oxidation reaction. The mutagenesis and structural simulation studies demonstrate the critical and unique role of each ligand in the function of HPPD, and which correlates with their respective co-ordination position.

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

    Directory of Open Access Journals (Sweden)

    Rikke Baek Sørensen

    Full Text Available BACKGROUND: 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. METHODS AND FINDINGS: 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. CONCLUSION: 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.

  1. 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.

  2. Synthesis of P,N-2,2’-biphenyl derivatives with central chirality

    Institute of Scientific and Technical Information of China (English)

    JEAN; Ludovic; POULIQUEN; Michael; BLANCHET; Jér?me; LASNE; Marie-Claire; ROUDEN; Jacques

    2010-01-01

    Enantiopure 2-(dicyclohexylphosphino)-1,1’-biphenyl derivatives substituted in the 2’-position by a chiral amino group were prepared.For the compound bearing an acyclic chiral chain,the key step was a Suzuki coupling between bromobenzeneboronic acid and N-Boc-iodoaniline whereas an aromatic nucleophilic substitution allowed the introduction of a chiral pyrrolidine in the 2’-position of the biphenyl backbone.The efficiency of the P,N-biphenyl pyrrolidine derivatives as ligands in Pd-catalyzed arylaminations compares well with that of DavePhos ligand.

  3. Structural Basis for Substrate and Oxygen Activation in Homoprotocatechuate 2,3-Dioxygenase: Roles of Conserved Active Site Histidine-200

    OpenAIRE

    Kovaleva, Elena G.; Rogers, Melanie S.; Lipscomb, John D.

    2015-01-01

    Kinetic and spectroscopic studies have shown that the conserved active site residue His200 of the extradiol ring-cleaving homoprotocatechuate 2,3-dioxygenase (FeHPCD) from Brevibacterium fuscum is critical for efficient catalysis. The roles played by this residue are probed here by analysis of the steady state kinetics, pH dependence, and X-ray crystal structures of the FeHPCD position 200 variants His200Asn, His200Gln, and His200Glu alone and in complex with three catecholic substrates (homo...

  4. Gene

    Data.gov (United States)

    U.S. Department of Health & Human Services — Gene integrates information from a wide range of species. A record may include nomenclature, Reference Sequences (RefSeqs), maps, pathways, variations, phenotypes,...

  5. Polychlorinated biphenyls: persistent pollutants with immunological, neurological, and endocrinological consequences.

    Science.gov (United States)

    Crinnion, Walter J

    2011-03-01

    Polychlorinated biphenyls (PCBs) are considered "persistent organic pollutants;" fat-soluble compounds that bioaccumulate in individuals and bio-magnify in the food chain. PCBs were the first industrial compounds to experience a worldwide ban on production because of their potent toxicity. These compounds are still present in our food supply (fish, dairy, hamburger, and poultry being the most contaminated) and our bodies. Once in the body, they can cause long-term problems, especially for those exposed in utero. PCB bioaccumulation can lead to reduced infection fighting ability, increased rates of autoimmunity, cognitive and behavioral problems, and hypothyroidism. Some research also links PCBs to increased rates of type 2 diabetes. Testing is currently available for some of the most damaging PCBs. The testing compares individual levels to national reference values and can be interpreted to determine current exposure. Dietary measures can be enacted that will reduce PCB half-lives in humans by increasing excretion.

  6. Bis(4-carbamoylpiperidinium biphenyl-4,4′-disulfonate

    Directory of Open Access Journals (Sweden)

    Graham Smith

    2010-12-01

    Full Text Available In the title isonipecotamide salt 2C6H13N2O+·C12H8O6S22−, the asymmetric unit comprises one biphenyl-4,4′-disulfonate dianion which lies across a crystallographic inversion centre and another in a general position [dihedral angle between the two phenyl rings is 37.1 (1°], together with three isonipecotamide cations. Two of these cations give a cyclic homomeric amide–amide dimer interaction [graph set R22(8], the other giving a similar dimeric interaction but across an inversion centre, both dimers then forming lateral cyclic R42(8 pyrimidinium–amide N—H...O interactions. These units are linked both laterally and longitudinally to the sulfonate groups of the dianions through piperidinium N—H...O hydrogen bonds, giving a three-dimensional framework structure.

  7. Polychlorinated biphenyls and organochlorine pesticides in plastics ingested by seabirds.

    Science.gov (United States)

    Colabuono, Fernanda Imperatrice; Taniguchi, Satie; Montone, Rosalinda Carmela

    2010-04-01

    The occurrence of plastic objects in the digestive tract was assessed in eight species of Procellariiformes collected in southern Brazil and the occurrence of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in the ingested plastics pellets and plastic fragments was evaluated. PCBs were detected in plastic pellets (491 ng g(-1)) and plastic fragments (243-418 ng g(-1)). Among the OCPs, p,p'-DDE had the highest concentrations, ranging from 68.0 to 99.0 ng g(-1). The occurrence of organic pollutants in post-consumer plastics supports the fact that plastics are an important source carrying persistent organic pollutants in the marine environment. Although transfer through the food chain may be the main source of exposure to POPs to seabirds, plastics could be an additional source for the organisms which ingest them, like Procellariiformes which are the seabirds most affected by plastic pollution.

  8. Determination of polychlorinated biphenyls (PCBs) in insulating oil

    Energy Technology Data Exchange (ETDEWEB)

    Fujimoto, S.; Goda, Y.; Hirobe, M. [Japan EnvironChemicals Ltd., Tokyo (Japan); Tomita, J.; Nishikiori, M.; Nakajima, T. [Tokyo Electric Power Environmental Engineering Co. Inc., Tokyo (Japan); Rubio, F. [Abraxis LLC, Warminster, PA (United States); Takigami, H. [National Inst. for Environmental Studies, Tsukuba (Japan); Sakai, S. [Kyoto Univ., Kyoto (Japan); Ike, M.; Fujita, M. [Osaka Univ., Osaka (Japan)

    2005-07-01

    This paper described a newly developed cocktail polychlorinated biphenyl (PCB) enzyme-linked immunosorbent assay (ELISA) designed as a pretreatment method for determining levels of PCBs in insulating oils. Standard and pretreated PCBs were dissolved in dimethyl sulfoxide (DMSO) and mixed. The diluted mixture was then combined with a horseradish peroxidase conjugate combined with an anti-PCB antibody coupled with magnetic particles. A comparison of the method with standard ELISA processes indicated that the cocktail showed that cross reactivity patterns were improved. Twenty-six insulating oil samples contaminated with PCBs were then analyzed using the method. Values obtained using the cocktail method correlated with gas chromatography (GC) and mass spectroscopy (MS) analyses conducted on the same samples. It was concluded that the cocktail ELISA technique is a reliable and simple analytical method for determining PCBs in insulating oils. 3 refs., 4 tabs., 2 figs.

  9. Fluorescence characteristics of polychlorinated biphenyl isomers in cyclodextrin media

    Energy Technology Data Exchange (ETDEWEB)

    Femia, R.A.; Scypinski, S.; Love, L.J.C.

    1985-01-01

    The fluorescence characteristics of several polychlorinated biphenyl (PCB) isomers in ..cap alpha..- and ..beta..-cyclodextrin (CD) are discussed and contrasted. The steric hindrance of PCBs imposed by the positions of the chlorine atoms on the rings determines the overall stability of the resulting inclusion complexes with cyclodextrin which is reflected in the fluorescence intensities. Less substituted homologues include into the CD cavity equally well in both cyclodextrins, but very heavily substituted molecules show drastic differences between their fluorescence intensities in the ..cap alpha..- and ..beta..-cyclodextrin solutions. This behavior can be employed as a method for spectral fractionation of PCB isomers. Spectral separation is demonstrated here for two variably substituted molecules, and the photophysical limitations of this approach are discussed.

  10. Guidance on the management of polychlorinated biphenyls (PCBs)

    Energy Technology Data Exchange (ETDEWEB)

    1993-11-01

    Polychlorinated biphenyls (PCBs) are a class of synthetic organic chemicals including 209 known isomers, each with from 1 to 10 chlorine atoms on a biphenyl ring. PCBs have a number of desirable properties for industrial applications including thermal stability, flame retardance, and low vapor pressure. Because of these properties, PCBs were widely used as dielectric fluid in electrical equipment such as utility transformers and capacitors. PCBs were also extensively used in hydraulic fluid and heat transfer fluid, in gaskets, as additives in cutting oils and lubricant, and in a variety of other uses. The Toxic Substances Control Act (TSCA) banned the manufacture of PCBs after 1978 in response to emerging information about the adverse health effects of PCBs and their persistence in the environment. In addition, TSCA directed the Administrator of the Environmental Protection Agency (EPA) to prescribe methods for disposal of PCBS, require marking of PCBs with warning labels, and control their use. The TSCA regulations allow continued use of PCBs provided that the use is totally enclosed and does not pose a risk to human health or the environment. However, at the end of their useful life, all PCB materials must be disposed of according to the TSCA regulations. This guidance document uses graphics and flow charts where possible to present the TSCA regulations according to management activities such as use, storage, disposal, and spill cleanup. The document is designed to be read on an as-needed basis; that is, each chapter can stand alone or may be read in combination with others to help the reader determine the regulations relevant to his or her individual situation and needs. Every attempt has been made to include the requirements of other statutes and regulations that apply to PCB materials and provide references for the reader to consult for additional information.

  11. Overexpression of Crocus carotenoid cleavage dioxygenase, CsCCD4b, in Arabidopsis imparts tolerance to dehydration, salt and oxidative stresses by modulating ROS machinery.

    Science.gov (United States)

    Baba, Shoib Ahmad; Jain, Deepti; Abbas, Nazia; Ashraf, Nasheeman

    2015-09-15

    Apocarotenoids modulate vital physiological and developmental processes in plants. These molecules are formed by the cleavage of carotenoids, a reaction catalyzed by a family of enzymes called carotenoid cleavage dioxygenases (CCDs). Apocarotenoids like β-ionone and β-cyclocitral have been reported to act as stress signal molecules during high light stress in many plant species. In Crocus sativus, these two apocarotenoids are formed by enzymatic cleavage of β-carotene at 9, 10 and 7, 8 bonds by CsCCD4 enzymes. In the present study three isoforms of CsCCD4 were subjected to molecular modeling and docking analysis to determine their substrate specificity and all the three isoforms displayed high substrate specificity for β-carotene. Further, expression of these three CsCCD4 isoforms investigated in response to various stresses revealed that CsCCD4a and CsCCD4b exhibit enhanced expression in response to dehydration, salt and methylviologen, providing a clue towards their role in mediating plant defense response. This was confirmed by overexpressing CsCCD4b in Arabidopsis. The transgenic plants developed longer roots and possessed higher number of lateral roots. Further, overexpression of CsCCD4b imparted enhanced tolerance to salt, dehydration and oxidative stresses as was evidenced by higher survival rate, increased relative root length and biomass in transgenic plants as compared to wild type. Transgenic plants also displayed higher activity and expression of reactive oxygen species (ROS) metabolizing enzymes. This indicates that β-ionone and β-cyclocitral which are enzymatic products of CsCCD4b may act as stress signals and mediate reprogramming of stress responsive genes which ultimately leads to plant defense.

  12. The tryptophan derivative, tranilast, and conditioned medium with indoleamine 2,3-dioxygenase-expressing cells inhibit the proliferation of lymphoid malignancies.

    Science.gov (United States)

    Suwa, Shihoko; Kasubata, Aya; Kato, Miyu; Iida, Megumi; Watanabe, Ken; Miura, Osamu; Fukuda, Tetsuya

    2015-03-01

    Indoleamine 2,3-dioxygenase (IDO) is an enzyme that catalyzes tryptophan degradation and induces immunosuppression. Although IDO is an important factor that allows tumors to escape from immunological attack, its effect on lymphoid malignancies has not been fully revealed. We evaluated the expression of IDO in samples from patients with B-cell malignancies. The IDO expression in the tumor samples was comparable to those in peripheral blood mononuclear cells from healthy donors and had mainly originated from non-B cell populations. We introduced IDO gene into Chinese hamster ovary (CHO) cells. We then cultured various cell lines using CHO- or CHO-IDO-conditioned medium. Compared with the CHO medium (CHO-CM), the CHO-IDO medium (IDO-CM) decreased the viability of lymphoid cell lines but not those of the non-lymphoid lines. Next, we examined the effects of tryptophan metabolites on lymphoid tumors, and revealed that the drug N-[3',4'-dimethoxycinnamoyl] anthranilic acid (tranilast), a synthetic derivative of the tryptophan metabolite, was able to repress proliferation and dose-dependently induce cell death of lymphoid cell lines. Tranilast induced the activation of the c-Jun N-terminal kinase, which is activated by cellular stress, in lymphoid cells. The effect of tranilast on lymphoid cells was independent of the aryl hydrocarbon receptor (AhR) although tranilast has been reported to be an AhR agonist. Finally, the administration of tranilast decreased murine lymphoid tumor progression in vivo. These results indicated that IDO and tryptophan derivatives, particularly tranilast, can be tools for the therapy for lymphoid malignancies.

  13. A Chloroflexi bacterium dechlorinates polychlorinated biphenyls in marine sediments under in situ-like biogeochemical conditions.

    Science.gov (United States)

    Zanaroli, Giulio; Balloi, Annalisa; Negroni, Andrea; Borruso, Luigimaria; Daffonchio, Daniele; Fava, Fabio

    2012-03-30

    We investigated the reductive dechlorination of Aroclor 1254 PCBs by a coplanar PCB-dechlorinating microbial community enriched from an actual site contaminated marine sediment of the Venice lagoon in sterile slurry microcosms of the same sediment suspended in its site water, i.e., under biogeochemical conditions that closely mime those occurring in situ. The culture dechlorinated more than 75% of the penta- through hepta-chlorinated biphenyls to tri- and tetra-chlorinated congeners in 30 weeks. The dechlorination rate was reduced by the addition of H(2) and short chain fatty acids, which stimulated sulfate-reduction and methane production, and markedly increased by the presence of vancomycin or ampicillin. DGGE analysis of 16S rRNA genes on PCB-spiked and PCB-free cultures ruled out sulfate-reducing and methanogenic bacteria and revealed the presence of a single Chloroflexi phylotype closely related to the uncultured bacteria m-1 and SF1 associated to PCB dechlorination. These findings suggest that a single dechlorinator is responsible for the observed extensive dechlorination of Aroclor 1254 and that a Chloroflexi species similar to those already detected in freshwater and estuarine contaminated sediments mediates PCB dechlorination in the marine sediment adopted in this study under biogeochemical conditions resembling those occurring in situ in the Brentella Canal of Venice Lagoon.

  14. 78 FR 20640 - Polychlorinated Biphenyls (PCBs); Recycling Plastics from Shredder Residue

    Science.gov (United States)

    2013-04-05

    ... AGENCY Polychlorinated Biphenyls (PCBs); Recycling Plastics from Shredder Residue AGENCY: Environmental... will generally allow for the recycling of plastic separated from shredder residue under the conditions described in the Voluntary Procedures for Recycling Plastics from Shredder Residue, relying principally...

  15. Uptake of polychlorinated biphenyls and organochlorine pesticides from soil and air into radishes (Raphanus sativus)

    DEFF Research Database (Denmark)

    Mikes, Ondrej; Cupr, P.; Trapp, Stefan

    2009-01-01

    Uptake of organochlorine pesticides and polychlorinated biphenyls from soil and air into radishes was measured at a heavily contaminated field site. The highest contaminant concentrations were found for DDT and its metabolites, and for beta-hexachlorocyclohexane. Bioconcentration factor (BCF...

  16. COMPARING POLYCHLORINATED BIPHENYLS IN FARM-RAISED AND WILD-CAUGHT CATFISH FROM SOUTHERN MISSISSIPPI

    Science.gov (United States)

    Polychlorinated biphenyls (PCBs) are among the most thermally stable organic chemicals known. This characteristic has historically made them useful in a wide array of applications including use in electrical transformers and capacitors, varnishes, waxes, synthetic resins, epoxy ...

  17. Perinatal exposure to polychlorinated biphenyls and dioxins and its effect on neonatal neurological development

    NARCIS (Netherlands)

    Huisman, M.; Koopman-Esseboom, C.; Fidler, V.; Hadders-Algra, M.; Paauw, C.G. van der; Tuinstra, L.G.M.Th.; Weisglas-Kuperus, N.; Sauer, P.J.J.; Touwen, B.C.L.; Boersma, E.R.

    1995-01-01

    Polychlorinated biphenyls (PCBs) and dioxins (polychlorinated dibenzo-p-dioxins (PCDDs), and dibenzofurans (PCDFs)) are widespread environmental contaminants which are neurotoxic in animals. Perinatal exposure to PCBs, PCDDs, and PCDFs occurs prenatally via the placenta and postnatally via breast mi

  18. Biphenyl synthase from yeast-extract-treated cell cultures of Sorbus aucuparia.

    Science.gov (United States)

    Liu, Benye; Beuerle, Till; Klundt, Tim; Beerhues, Ludger

    2004-01-01

    Biphenyls and dibenzofurans are the phytoalexins of the Maloideae, a subfamily of the economically important Rosaceae. The biphenyl aucuparin accumulated in Sorbus aucuparia L. cell cultures in response to yeast extract treatment. Incubation of cell-free extracts from challenged cell cultures with benzoyl-CoA and malonyl-CoA led to the formation of 3,5-dihydroxybiphenyl. This reaction was catalysed by a novel polyketide synthase, which will be named biphenyl synthase. The most efficient starter substrate for the enzyme was benzoyl-CoA. Relatively high activity was also observed with 2-hydroxybenzoyl-CoA but, instead of the corresponding biphenyl, the derailment product 2-hydroxybenzoyltriacetic acid lactone was formed.

  19. PERINATAL EXPOSURE TO POLYCHLORINATED-BIPHENYLS AND DIOXINS AND ITS EFFECT ON NEONATAL NEUROLOGICAL DEVELOPMENT

    NARCIS (Netherlands)

    HUISMAN, M; KOOPMANESSEBOOM, C; FIDLER, [No Value; HADDERSALGRA, M; VANDERPAAUW, CG; TUINSTRA, LGMT; WEISGLASKUPERUS, N; SAUER, PJJ; TOUWEN, BCL; BOERSMA, ER

    1995-01-01

    Polychlorinated biphenyls (PCBs) and dioxins (polychlorinated dibenzo-p-dioxins (PCDDs), and dibenzofurans (PCDFs)) are widespread environmental contaminants which are neurotoxic in animals. Perinatal exposure to PCBs, PCDDs, and PCDFs occurs prenatally via the placenta and postnatally via breast mi

  20. Spermatogenic capacity in fertile men with elevated exposure to polychlorinated biphenyls

    DEFF Research Database (Denmark)

    Petersen, Maria Skaalum; Halling, Jónrit; Weihe, Pál

    2015-01-01

    BACKGROUND: Endocrine disrupting industrial chemicals, such as polychlorinated biphenyls (PCBs), are suspected to adversely affect male reproductive functions. OBJECTIVES: The Faroe Islands community exhibits an unusually wide range of exposures to dietary contaminants, and in this setting we...

  1. Immunologic effects of background exposure to polychlorinated biphenyls and dioxins in Dutch preschool children

    NARCIS (Netherlands)

    N. Weisglas-Kuperus (Nynke); S. Patandin (Svati); G.A. Berbers; T.C.J. Sas (Theo); P.J.J. Sauer (Pieter); H. Hooijkaas (Herbert); P.G.H. Mulder (Paul)

    2000-01-01

    textabstractPrenatal exposure to polychlorinated biphenyls (PCBs) and dioxins is associated with changes in the T-cell lymphocyte population in healthy Dutch infants. We investigated whether these changes persist into later childhood and whether background exposure to P

  2. POLYCHLORINATED BIPHENYLS IN HOUSE DUST AND YARD SOIL NEAR A SUPERFUND SITE. (R825173)

    Science.gov (United States)

    Polychlorinated biphenyls (PCBs) were measured in house dust and yard soil at 34 homes surrounding New Bedford Harbor during dredging of highly contaminated harbor sediments. PCBs can volatilize from sediments and seawater and subsequently deposit on surrounding soil, resulting i...

  3. Polychlorinated biphenyl (PCB) removal from the Kenai National Wildlife Refuge, Alaska, October 1984 and 1988

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report covers the removal of polychlorinated biphenyl (PCB) from Kenai National Wildlife Refuge in Alaska during October 1984 and 1985. Atlantic Ritchfield...

  4. Effect of highly bioaccumulated polychlorinated biphenyl congeners on estrogen and androgen receptor activity

    DEFF Research Database (Denmark)

    Bonefeld-Jørgensen, E.C.; Andersen, H. R.; Rasmussen, T.H.;

    2001-01-01

    Polychlorinated biphenyls (PCBs) are ubiquitous environmental persistent contaminants giving rise to potential health hazard. Some PCBs exert dioxin-like activities mediated through the aryl hydrocarbon receptor. Although reports on interaction with other nuclear receptors are sparce, some...

  5. 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.

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

    Directory of Open Access Journals (Sweden)

    Katarzyna Hupert-Kocurek

    2014-01-01

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

  7. Molecular basis for catalysis and substrate-mediated cellular stabilization of human tryptophan 2,3-dioxygenase

    Science.gov (United States)

    Lewis-Ballester, Ariel; Forouhar, Farhad; Kim, Sung-Mi; Lew, Scott; Wang, YongQiang; Karkashon, Shay; Seetharaman, Jayaraman; Batabyal, Dipanwita; Chiang, Bing-Yu; Hussain, Munif; Correia, Maria Almira; Yeh, Syun-Ru; Tong, Liang

    2016-01-01

    Tryptophan 2,3-dioxygenase (TDO) and indoleamine 2,3-dioxygenase (IDO) play a central role in tryptophan metabolism and are involved in many cellular and disease processes. Here we report the crystal structure of human TDO (hTDO) in a ternary complex with the substrates L-Trp and O2 and in a binary complex with the product N-formylkynurenine (NFK), defining for the first time the binding modes of both substrates and the product of this enzyme. The structure indicates that the dioxygenation reaction is initiated by a direct attack of O2 on the C2 atom of the L-Trp indole ring. The structure also reveals an exo binding site for L-Trp, located ~42 Å from the active site and formed by residues conserved among tryptophan-auxotrophic TDOs. Biochemical and cellular studies indicate that Trp binding at this exo site does not affect enzyme catalysis but instead it retards the degradation of hTDO through the ubiquitin-dependent proteasomal pathway. This exo site may therefore provide a novel L-Trp-mediated regulation mechanism for cellular degradation of hTDO, which may have important implications in human diseases. PMID:27762317

  8. Multistep conversion of para-substituted phenols by phenol hydroxylase and 2,3-dihydroxybiphenyl 1,2-dioxygenase.

    Science.gov (United States)

    Qu, Yuanyuan; Shi, Shengnan; Ma, Qiao; Kong, Chunlei; Zhou, Hao; Zhang, Xuwang; Zhou, Jiti

    2013-04-01

    A multistep conversion system of para-substituted phenols by recombinant phenol hydroxylase (PH(IND)) and 2,3-dihydroxybiphenyl 1,2-dioxygenase (BphC(LA-4)) was constructed in this study. Docking studies with different para-substituted phenols and corresponding catechols inside of the active site of PH(IND) and BphC(LA-4) predicted that all the substrates should be transformed. High-performance liquid chromatography-mass spectrometry analysis showed that the products of multistep conversion were the corresponding para-substituted catechols and semialdehydes. For the first-step conversion, the formation rate of 4-fluorocatechol (0.39 μM/min/mg dry weight) by strain PH(IND) hydroxylation was 1.15, 6.50, 3.00, and 1.18-fold higher than the formation of 4-chlorocatechol, 4-bromocatechol, 4-nitrocatechol, and 4-methylcatechol, respectively. For the second-step conversion, the formation rates of semialdehydes by strain BphC(LA-4) were as follows: 5-fluoro-HODA>5-chloro-HODA>2-hydroxy-5-nitro-ODA>5-bromo-HODA>2-hydroxy-5-methyl-ODA. The present study suggested that the multistep conversion by both ring hydroxylase and cleavage dioxygenase should be potential in the synthesis of industrial precursors and provide a novel avenue in the wastewater recycling treatment.

  9. Biphenyl Phytoalexin in Sorbus pohuashanensis Suspension Cell Induced by Yeast Extract

    OpenAIRE

    Liangyun Zhou; Jian Yang; Guang Yang; Chuanzhi Kang; Wenjuan Xiao; Chaogeng Lv; Sheng Wang; Jinfu Tang; Lanping Guo

    2016-01-01

    Biphenyls are unique phytoalexins de novo synthesized in plants in response to pathogen attack. These compounds are found in Maloideae, a subfamily of the Rosaceae. The anti-microbial activities of biphenyls have been reported in a number of studies and they appear to represent an important defense strategy against pathogens common in the Maloideae, such as species in Malus, Pyrus, Sorbus, and Chaenomeles. Here, cell suspension cultures of Sorbus pohuashanensis were established to study biphe...

  10. Investigation of mechanisms of formation of biphenyls and benzonaphthothiophenes by simulation experiment

    Institute of Scientific and Technical Information of China (English)

    XIA; Yanqing(夏燕青); ZHANG; Gengxin(张更新)

    2002-01-01

    The formation mechanisms of biphenyl series and benzonaphthothiophene series are investigated by means of simulation experiment. Biphenyl series are likely formed in two ways: one is the aromatization of the chain compounds containing conjugated C== C double bonds or the compounds with such a kind of sidechains, and the other is the reaction of sulfur with ordinary chain compounds, in which sulphur acts on ordinary sidechain compounds by seizing some hydrogens and forming (H2S and) the intermediates with conjugated C== C double bonds first, and then the intermediates are aromatized. One of the basic precursors of benzonaphthothiophenes is likely the phenylnaphthalenes which may originate from the chain compounds containing conjugated C== C double bonds, the compounds with such sidechains and saturate or unsaturate chain compounds. Thermal stability of biphenyls is high, but they can become dibenzothiophenes and polycyclic aromatic hydrocarbons or dibenzofurans and polycyclic aromatic hydrocarbons respectively in the presence of sulphur or oxygen. The ratio of biphenyl and m-biphenyl to biphenyls may be employed to indicate the depositional environment in the mild to medium maturation, of which the higher value indicates a fresh water depositional environment and the lower indicates a saline depositional environment. The relative high content of benzonaphthothiophenes in the crude oil indicates that the crude oil has undergone an intense sulfurization in the source rock or reservoir.

  11. Investigation of saponification for determination of polychlorinated biphenyls in marine sediments.

    Science.gov (United States)

    Numata, Masahiko; Yarita, Takashi; Aoyagi, Yoshie; Yamazaki, Misako; Takatsu, Akiko

    2005-02-01

    The effects of saponification conditions (temperature and water content of saponifying solution) on the determination of chlorinated biphenyls (CBs) in marine sediments were investigated. Although highly chlorinated biphenyls (nona- to deca-CBs) decomposed during high-temperature saponification, the degree of degradation was reduced by adding water to the ethanolic potassium hydroxide saponifying solution. Room-temperature saponification yielded quantitative recovery of highly chlorinated biphenyl surrogates but low extraction efficiencies of lightly chlorinated biphenyls (mono- to di-CBs). The same samples were analyzed by other extraction techniques, for example, pressurized liquid extraction, and analytical results were compared. The mono- and di-CB concentrations were correlated with the extraction temperatures of various extraction techniques. In particular, the concentrations of some CB congeners (CB11, CB14) were higher with saponification. The low degree of degradation of highly chlorinated biphenyls and the high recovery of lightly chlorinated biphenyls were compatible when room-temperature and high-temperature saponification were combined. Except for the anomalies of CB11 and CB14, the combined method gave satisfactory results for analysis of PCBs.

  12. Regional analysis of potential polychlorinated biphenyl degrading bacterial strains from China

    Directory of Open Access Journals (Sweden)

    Jianjun Shuai

    Full Text Available ABSTRACT Polychlorinated biphenyls (PCBs, the chlorinated derivatives of biphenyl, are one of the most prevalent, highly toxic and persistent groups of contaminants in the environment. The objective of this study was to investigate the biodegradation of PCBs in northeastern (Heilongjiang Province, northern (Shanxi Province and eastern China (Shanghai municipality. From these areas, nine soil samples were screened for PCB-degrading bacteria using a functional complementarity method. The genomic 16S rDNA locus was amplified and the products were sequenced to identify the bacterial genera. Seven Pseudomonas strains were selected to compare the capacity of bacteria from different regions to degrade biphenyl by HPLC. Compared to the biphenyl content in controls of 100%, the biphenyl content went down to 3.7% for strain P9-324, 36.3% for P2-11, and 20.0% for the other five strains. These results indicate that a longer processing time led to more degradation of biphenyl. PCB-degrading bacterial strains are distributed differently in different regions of China.

  13. NO binding to Mn-substituted homoprotocatechuate 2,3-dioxygenase: relationship to O₂ reactivity.

    Science.gov (United States)

    Hayden, Joshua A; Farquhar, Erik R; Que, Lawrence; Lipscomb, John D; Hendrich, Michael P

    2013-10-01

    Iron(II)-containing homoprotocatechuate 2,3-dioxygenase (FeHPCD) activates O2 to catalyze the aromatic ring opening of homoprotocatechuate (HPCA). The enzyme requires Fe(II) for catalysis, but Mn(II) can be substituted (MnHPCD) with essentially no change in the steady-state kinetic parameters. Near simultaneous O2 and HPCA activation has been proposed to occur through transfer of an electron or electrons from HPCA to O2 through the divalent metal. In O2 reactions with MnHPCD-HPCA and the 4-nitrocatechol (4NC) complex of the His200Asn (H200N) variant of FeHPCD, this transfer has resulted in the detection of a transient M(III)-O2 (·-) species that is not observed during turnover of the wild-type FeHPCD. The factors governing formation of the M(III)-O2 (·-) species are explored here by EPR spectroscopy using MnHPCD and nitric oxide (NO) as an O2 surrogate. Both the HPCA and the dihydroxymandelic substrate complexes of MnHPCD bind NO, thus representing the first reported stable MnNO complexes of a nonheme enzyme. In contrast, the free enzyme, the MnHPCD-4NC complex, and the MnH200N and MnH200Q variants with or without HPCA bound do not bind NO. The MnHPCD-ligand complexes that bind NO are also active in normal O2-linked turnover, whereas the others are inactive. Past studies have shown that FeHPCD and the analogous variants and catecholic ligand complexes all bind NO, and are active in normal turnover. This contrasting behavior may stem from the ability of the enzyme to maintain the approximately 0.8-V difference in the solution redox potentials of Fe(II) and Mn(II). Owing to the higher potential of Mn, the formation of the NO adduct or the O2 adduct requires both strong charge donation from the bound catecholic ligand and additional stabilization by interaction with the active-site His200. The same nonoptimal electronic and structural forces that prevent NO and O2 binding in MnHPCD variants may lead to inefficient electron transfer from the catecholic substrate to

  14. NO Binding to Mn-Substituted Homoprotocatechuate 2,3-Dioxygenase: Relationship to O2 Reactivity

    Science.gov (United States)

    Hayden, Joshua A.; Farquhar, Erik R.; Que, Lawrence; Lipscomb, John D.; Hendrich, Michael P.

    2014-01-01

    Homoprotocatechuate 2,3-dioxygenase (FeHPCD) activates O2 to catalyze the aromatic ring opening of 3,4-dihydroxyphenylacetic acid (HPCA). The enzyme requires FeII for catalysis, but MnII can be substituted (MnHPCD) with essentially no change in the steady-state kinetic parameters. Near simultaneous O2 and HPCA activation has been proposed to occur through transfer of an electron(s) from HPCA to O2 through the divalent metal. In O2 reactions with MnHPCD-HPCA and the 4-nitrocatechol (4NC) complex of the His200Asn (H200N) variant of FeHPCD, this transfer has resulted in the detection of a transient MIII-O2•− species not observed during turnover of the wild type FeHPCD. The factors governing formation of the MIII-O2•− species are explored here with EPR spectroscopy using MnHPCD and nitric oxide (NO) as an O2 surrogate. Both the HPCA and dihydroxymandelic substrate complexes of MnHPCD bind NO, thus representing the first reported stable MnNO complexes of a nonheme enzyme. In contrast, the free enzyme, the MnHPCD-4NC complex, and the MnH200N and MnH200Q variants with or without HPCA bound do not bind NO. The MnHPCD-ligand complexes that bind NO are also active in normal O2-linked turnover, whereas the others are inactive. Past studies have shown that FeHPCD and the analogous variants and catecholic ligand complexes all bind NO, and are active in normal turnover. This contrasting behavior may stem from ability of the enzyme to maintain the ~0.8 V difference in the solution redox potentials of FeII and MnII. Due to the higher potential of Mn, the formation of the NO or O2 adduct requires both strong charge donation from the bound catecholic ligand and additional stabilization by interaction with the active site His200. The same non-optimal electronic and structural forces that prevent NO and O2 binding in MnHPCD variants may lead to inefficient electron transfer from the catecholic substrate to the metal center in variants of FeHPCD during O2-linked turnover

  15. Characterization of metal binding in the active sites of acireductone dioxygenase isoforms from Klebsiella ATCC 8724.

    Science.gov (United States)

    Chai, Sergio C; Ju, Tingting; Dang, Marina; Goldsmith, Rachel Beaulieu; Maroney, Michael J; Pochapsky, Thomas C

    2008-02-26

    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 M2+ metal ion bound in the active site. The Ni2+-bound NiARD catalyzes an off-pathway shunt from the methionine salvage pathway leading to the production of formate, methylthiopropionate, and carbon monoxide, while the Fe2+-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 metal in vivo but

  16. 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.

  17. Structure-activity relationships for interaction with multidrug resistance protein 2 (ABCC2/MRP2): the role of torsion angle for a series of biphenyl-substituted heterocycles.

    Science.gov (United States)

    Lai, Yurong; Xing, Li; Poda, Gennadiy I; Hu, Yiding

    2007-06-01

    Multidrug resistance protein 2 (ABCC2/MRP2) is an ATP-binding cassette transporter involved in the absorption, distribution, and excretion of drugs and xenobiotics. Identifying compounds that are ABCC2/MRP2 substrates and/or inhibitors and understanding their structure-activity relationships (SARs) are important considerations in the selection and optimization of drug candidates. In the present study, the interactions between ABCC2/MRP2 and a series of biphenyl-substituted heterocycles were evaluated using Caco-2 cells and human ABCC2/MRP2 gene-transfected Madin-Darby canine kidney cells. It was observed that ABCC2/MRP2 transport and/or inhibition profile, both in nature and in magnitude, depends strongly on the substitution patterns of the biphenyl system. In particular, different ortho-substitutions cause various degrees of twisting between the two-phenyl rings, resulting in changing interactions between the ligands and ABCC2/MRP2. The compounds with small ortho functions (hydrogen, fluorine, and oxygen) and, thus, the ones displaying the smallest torsion angles of biphenyl (37-45 degrees) are neither substrates nor inhibitors of human ABCC2/MRP2. The transporter interactions increase as the steric bulkiness of the ortho-substitutions increase. When the tested compounds are 2-methyl substituted biphenyls, they exhibit moderate torsion angles (54-65 degrees) and behave as ABCC2/MRP2 substrates as well as mild inhibitors [10-40% compared with 3-[[3-[2-(7-chloroquinolin-2-yl)vinyl]phenyl]-(2-dimethylcarbamoylethyl-sulfanyl)methylsulfanyl] propionic acid (MK571)]. For the 2,2'-dimethyl substituted biphenyls, the torsions are enhanced (78-87 degrees) and so is the inhibition of ABCC2/MRP2. This class of compounds behaves as strong inhibitors of ABCC2/MRP2. These results can be used to define the three-dimensional structural requirements of ABCC2/MRP2 interaction with their substrates and inhibitors, as well as to provide SAR guidance to support drug discovery.

  18. Modeling the 2-His-1-Carboxylate Facial Triad: Iron-Catecholato Complexes as Structural and Functional Models of the Extradiol Cleaving Dioxygenases

    NARCIS (Netherlands)

    Bruijnincx, P.C.A.; Lutz, M.; Spek, A.L.; Hagen, W.R.; Weckhuysen, B.M.; van Koten, G.; Klein Gebbink, R.J.M.

    2007-01-01

    Mononuclear iron(II)- and iron(III)-catecholato complexes with three members of a new 3,3-bis(1-alkylimidazol-2-yl)propionate ligand family have been synthesized as models of the active sites of the extradiol cleaving catechol dioxygenases. These enzymes are part of the superfamily of dioxygen-activ

  19. The use of the DR CALUX bioassay and indicator polychlorinated biphenyls for screening of elevated levels of dioxins and dioxin-like polychlorinated biphenyls in eel.

    NARCIS (Netherlands)

    Hoogenboom, Ron; Bovee, Toine; Traag, Win A; Hoogerbrugge, Ronald; Baumann, Bert; Portier, Liza; Weg, Guido van de; Vries, Jaap de

    2006-01-01

    The DR CALUX bioassay is a very suitable screening method for dioxins and dioxin-like-PCBs in feed and food. This was, e. g. demonstrated in a survey in the Netherlands to control the dioxin levels in eel. The DR CALUX assay, but also indicator polychlorinated biphenyls (PCB) were evaluated as a scr

  20. Kinetics of polychlorinated biphenyl partitioning to marine Chrysophyte Isochrysis galbana

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Fung-Chi, E-mail: ko@nmmba.gov.tw [National Dong Hwa University, Institute of Marine Biodiversity and Evolutionary Biology, Taiwan, ROC (China); National Museum of Marine Biology and Aquarium, Pingtung, Taiwan, ROC (China); Baker, Joel E. [The Center for Urban Waters, University of Washington, Tacoma, WA 98402 (United States); Tew, Kwee S. [National Dong Hwa University, Institute of Marine Biodiversity and Evolutionary Biology, Taiwan, ROC (China); National Museum of Marine Biology and Aquarium, Pingtung, Taiwan, ROC (China)

    2012-02-01

    This study focused on the uptake kinetics of polychlorinated biphenyl (PCB) congeners by the Chrysophyte, Isochrysis galbana. A gas-purging experimental system was used to maintain constant dissolved PCB concentrations. Three phases of absorption were observed: first, a rapid absorption phase within the first 15 min, second, a first order process reaching the maximum concentration within 48 h of exposure, and third, a plateau phase as yet to be determined with very slight increases in concentration. In this study, the percentage of the maximum concentration reached within the first phase varied from 10% to 67%, depending on the size of the PCB (as determined by molecular weight and total surface area), whereas the uptake rate (k{sub u}) during the second phase was more comparable across different PCBs. In addition, for the first phase, the bioconcentration factor (BCF) of PCBs deviated from its expected relationship with hydrophobicity, as determined by K{sub ow}, and was instead related to the molecular structure of the compound.

  1. Kinetics of polychlorinated biphenyl partitioning to marine Chrysophyte Isochrysis galbana.

    Science.gov (United States)

    Ko, Fung-Chi; Baker, Joel E; Tew, Kwee S

    2012-02-01

    This study focused on the uptake kinetics of polychlorinated biphenyl (PCB) congeners by the Chrysophyte, Isochrysis galbana. A gas-purging experimental system was used to maintain constant dissolved PCB concentrations. Three phases of absorption were observed: first, a rapid absorption phase within the first 15min, second, a first order process reaching the maximum concentration within 48h of exposure, and third, a plateau phase as yet to be determined with very slight increases in concentration. In this study, the percentage of the maximum concentration reached within the first phase varied from 10% to 67%, depending on the size of the PCB (as determined by molecular weight and total surface area), whereas the uptake rate (k(u)) during the second phase was more comparable across different PCBs. In addition, for the first phase, the bioconcentration factor (BCF) of PCBs deviated from its expected relationship with hydrophobicity, as determined by K(ow), and was instead related to the molecular structure of the compound.

  2. Polychlorinated Biphenyls Disrupt Hepatic Epidermal Growth Factor Receptor Signaling.

    Science.gov (United States)

    Hardesty, Josiah E; Wahlang, Banrida; Falkner, K Cameron; Clair, Heather B; Clark, Barbara J; Ceresa, Brian P; Prough, Russell A; Cave, Matthew C

    2016-07-26

    1. Polychlorinated biphenyls (PCBs) are persistent environmental pollutants that disrupt hepatic xenobiotic and intermediary metabolism, leading to metabolic syndrome and nonalcoholic steatohepatitis (NASH). 2. Since phenobarbital indirectly activates Constitutive Androstane Receptor (CAR) by antagonizing growth factor binding to the epidermal growth factor receptor (EGFR), we hypothesised that PCBs may also diminish EGFR signaling. 3. The effects of the PCB mixture Aroclor 1260 on the protein phosphorylation cascade triggered by EGFR activation were determined in murine (in vitro and in vivo) and human models (in vitro). EGFR tyrosine residue phosphorylation was decreased by PCBs in all models tested. 4. The IC50 values for Aroclor 1260 concentrations that decreased Y1173 phosphorylation of EGFR were similar in murine AML-12 and human HepG2 cells (∼2-4 μg/mL). Both dioxin and non-dioxin-like PCB congeners decreased EGFR phosphorylation in cell culture. 5. PCB treatment reduced phosphorylation of downstream EGFR effectors including Akt and mTOR, as well as other phosphoprotein targets including STAT3 and c-RAF in vivo. 6. PCBs diminish EGFR signaling in human and murine hepatocyte models and may dysregulate critical phosphoprotein regulators of energy metabolism and nutrition, providing a new mechanism of action in environmental diseases.

  3. Accumulation and efflux of polychlorinated biphenyls in Escherichia coli.

    Science.gov (United States)

    Geng, Shen; Fang, Jun; Turner, Kendrick B; Daunert, Sylvia; Wei, Yinan

    2012-06-01

    Polychlorinated biphenyls (PCBs) are environmental pollutants that have been associated with numerous adverse health effects in human and animals. Hydroxylated PCBs (HPCBs) are the product of the oxidative metabolism of PCBs. The presence of hydroxyl groups in HPCBs makes these compounds more hydrophilic than the parent PCBs. One of the best approaches to break down and remove these contaminants is bioremediation; an environmentally friendly process that uses microorganisms to degrade hazardous chemicals into non-toxic ones. In this study, we investigated the cellular accumulation and toxicity of selected PCBs and HPCBs in Gram-negative bacteria, using Escherichia coli as a model organism. We found that none of the five PCBs tested were toxic to E. coli, presumably due to their limited bioavailability. Nevertheless, different HPCBs tested showed different levels of toxicity. Furthermore, we demonstrated that the primary multidrug efflux system in E. coli, AcrAB-TolC, facilitated the efflux of HPCBs out of the cell. Since AcrAB-TolC is constitutively expressed in E. coli and is conserved in all sequenced Gram-negative bacterial genomes, our results suggest that the efflux activities of multidrug resistant pumps may affect the accumulation and degradation of PCBs in Gram-negative bacteria.

  4. Toxicity mechanisms and interactions of polychlorinated biphenyls and polybrominated diphenylethers

    Directory of Open Access Journals (Sweden)

    Antonijević Biljana

    2012-01-01

    Full Text Available Polychlorinated biphenyls (PCBs and brominated flame retardants, polybrominated diphenylethers (PBDEs, are widespread environmental contaminants as a result of anthropogenic activities and due to their persistency and resistance to degradation. Both groups of chemicals are placed on the list of persistent organic pollutants (POPs, covered by the Stockholm convention which is aimed to limit or ban the production, use, emission, import and export of POPs in order to protect human health and the environment. Taking into account the structural similarity between PCBs and PBDEs, and the known effects of PCBs, these two groups of chemicals could have similar mechanisms of action. Also, because of real simultaneous exposure to these compounds, an examination of possible interactions is of great importance. Interactions of the compounds from these groups are likely at the system level of hormones, particularly thyroid and reproductive ones. As there are mechanisms of adverse effects of both groups of chemicals on the nervous system, including functional, neurological and behavioral changes, there are influences on neurotransmiters, changes in signal transduction and apoptosis. There are interactions affecting the occurrence of metabolic disorders as well. Data on the toxicity of mixtures of PCBs and PBDEs, as well as interactions of these chemicals would contribute to the processes of risk evaluation and risk characterisation. [Projekat Ministarstva nauke Republike Srbije, br. III 46009

  5. Polychlorinated biphenyls and their interaction with the environment

    Energy Technology Data Exchange (ETDEWEB)

    Dickerson, K.S.; Korte, N.E.

    1994-05-01

    This document is a review of the existing technical literature regarding the physical and biological properties of polychlorinated biphenyls (PCBs) and their interaction with the environment. It is intended to be used when evaluating PCB-contaminated soil and the effects of specific environmental conditions on PCB degradation. PCBs are a class of chlorinated aromatic compounds with 209 possible structural arrangements. The composition of PCBs in the environment changes over time due to various physiochemical and biological properties and processes: vapor pressure, solubility, octanol-water partitioning, adsorption, and biodegradation. As the number of chlorine atoms increases, both vapor pressure and water solubility decrease, while adsorption and the octanol-water partitioning coefficient increase. Dechlorination of PCBs occurs primarily through aerobic and anaerobic microbial degradation. Aerobic bacteria preferentially dechlorinate less-chlorinated PCBs, while anaerobic bacteria preferentially dechlorinate more highly chlorinated PCBs. The less-chlorinated PCB congeners are less persistent in the environment due to volatilization, solubility, and aerobic biodegradation, while the more-chlorinated PCBs are more persistent in the environment due to adsorption. The composition of an original PCB mixture in the environment can be expected to change due to a combination of processes described above. Any attempt to determine the source of PCBs or Aroclors identified in an environment sample must be approached with caution to avoid inaccurate conclusions.

  6. Modeling polychlorinated biphenyl sorption isotherms for soot and coal

    Energy Technology Data Exchange (ETDEWEB)

    Jantunen, A.P.K.; Koelmans, A.A.; Jonker, M.T.O. [University of Utrecht, Utrecht (Netherlands)

    2010-08-15

    Sorption isotherms (pg-ng/L) were measured for 11 polychlorinated biphenyls (PCBs) of varying molecular planarity from aqueous solution to two carbonaceous geosorbents, anthracite coal and traffic soot. All isotherms were reasonably log-log-linear, but smooth for traffic soot and staircase-shaped for coal, to which sorption was stronger and more nonlinear. The isotherms were modeled using seven sorption models, including Freundlich, (dual) Langmuir, and Polanyi-Dubinin-Manes (PDM). PDM provided the best combination of reliability and mechanistically-interpretable parameters. The PDM normalizing factor Z appeared to correlate negatively with sorbate molecular volume, dependent on the degree of molecular planarity. The modeling results supported the hypothesis that maximum adsorption capacities (Q{sub max}) correlate positively with the sorbent's specific surface area. Q{sub max} did not decrease with increasing sorbate molecular size, and adsorption affinities clearly differed between the sorbents. Sorption was consistently stronger but not less linear for planar than for nonplanar PCBs, suggesting surface rather than pore sorption.

  7. Atmospheric emission of polychlorinated biphenyls from multiple industrial thermal processes.

    Science.gov (United States)

    Liu, Guorui; Zheng, Minghui; Cai, Mingwei; Nie, Zhiqiang; Zhang, Bing; Liu, Wenbin; Du, Bing; Dong, Shujun; Hu, Jicheng; Xiao, Ke

    2013-03-01

    In this study, field measurements were conducted to estimate and characterize the atmospheric emission levels and profiles of polychlorinated biphenyls (PCBs) from multiple industrial thermal processes. The emission levels and profiles of PCBs from five types of thermal processes at twenty-three plants were studied and compared with eight processes reported in our previous studies. Correlation analysis was preformed to identify a marker congener for emission of ΣPCB. A significant correlation was observed between congener CB-118 and ΣPCB (R(2)=0.65 and pemission of ΣPCB. The profiles of PCBs emitted from the thirteen thermal processes were compared, and this information could be used for studying source-receptor relationships and identifying the specific sources of PCBs. To prioritize the sources for control, the concentrations of PCBs from thirteen industrial thermal sources were compared. The PCB concentrations from secondary zinc smelting and thermal wire reclamation were about one to three order magnitude higher than those of other sources, which suggests that these two sources be given priority in PCB source control. Finally, the atmospheric emission factors of PCBs from the thirteen industrial sources were summarized, and these data will be useful for developing an integrated emission inventory of PCBs.

  8. Continuous catalytic hydrodechlorination of polychlorinated biphenyls (PCBs) in transformer oil.

    Science.gov (United States)

    Veriansyah, Bambang; Choi, Hye-Min; Lee, Youn-Woo; Kang, Jeong Won; Kim, Jae-Duck; Kim, Jaehoon

    2009-12-01

    Continuous catalytic hydrodechlorination of polychlorinated biphenyls (PCBs) in the presence of transformer oils was carried out in a fixed bed reactor using a 57.6 wt% Ni on silicon oxide-aluminum oxide (SiO(2)-Al(2)O(3)) catalyst. Reaction temperatures ranging 150-300 degrees C, PCBs concentrations ranging 50-200 ppm, and reaction times ranging 1-8 h were tested. At a higher reaction temperature or at a lower PCBs concentration, catalytic activity was higher and complete dechlorination of PCBs resulted even at long reaction time. Catalyst regeneration using hexane and 0.1 M sodium hydroxide (NaOH) was effective to restore the catalytic activity. Fresh, spent and regenerated catalysts were characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis. XRD analysis revealed growth of Ni crystallite size of the spent and the regenerated catalysts. XPS analysis showed that a considerable amount of chlorine and carbon species were deposited on the surface of the spent catalyst, which may play a role in the catalysts deactivation.

  9. Levels of polychlorinated biphenyls (PCBs) in transformer oils from Korea.

    Science.gov (United States)

    Shin, Sun Kyoung; Kim, Tae Seung

    2006-10-11

    Using Korean waste official method, polychlorinated biphenyls (PCBs) were analyzed from 33 transformer oils collected under National Institute of Environmental Research (NIER) in Republic of Korea (ROK) and their emission rate in Korea was estimated. Practical quantification limits analyzed by this method were in the ranges of 0.02 and 0.05 mg L(-1), and recovery of samples was in the ranges of 77-97%. The analytical results showed that PCBs in the transformer oils were identified as Aroclor 1242, 1254 or 1260. Twenty-nine samples were determined to contain PCBs of >0.05 mg L(-1) and among these samples, nine samples contained to have >2 mg kg(-1) which is limit of Waste Control Act (WCA) with regard to PCBs in transformer oil from Korea. The concentrations of PCBs in transformer oils were between N.D. (not detected) and 48.33 mg kg(-1). PCBs concentrations did not exceed 50 mg kg(-1) which is generally accepted limit for the definition of waste in POPs Guideline of Basel Convention.

  10. A comprehensive approach to actual polychlorinated biphenyls environmental contamination.

    Science.gov (United States)

    Risso, F; Magherini, A; Ottonelli, M; Magi, E; Lottici, S; Maggiolo, S; Garbarino, M; Narizzano, R

    2016-05-01

    Worldwide polychlorinated biphenyls (PCBs) pollution is due to complex mixtures with high number of congeners, making the determination of total PCBs in the environment an open challenge. Because the bulk of PCBs production was made of Aroclor mixtures, this analysis is usually faced by the empirical mixture identification via visual inspection of the chromatogram. However, the identification reliability is questionable, as patterns in real samples are strongly affected by the frequent occurrence of more than one mixture. Our approach is based on the determination of a limited number of congeners chosen to enable objective criteria for Aroclor identification, summing up the advantages of congener-specific analysis with the ones of total PCBs determination. A quantitative relationship is established between congeners and any single mixture, or mixtures combination, leading to the identification of the actual contamination composition. The approach, due to its generality, allows the use of different sets of congeners and any technical mixture, including the non-Aroclor ones. The results confirm that PCB environmental pollution in northern Italy is based on Aroclor. Our methodology represents an important tool to understand the source and fate of the PCBs contamination.

  11. Functional diversity of bacterial genes associated with aromatic hydrocarbon degradation in anthropogenic dark earth of Amazonia

    Directory of Open Access Journals (Sweden)

    Mariana Gomes Germano

    2012-05-01

    Full Text Available The objective of this work was to evaluate the catabolic gene diversity for the bacterial degradation of aromatic hydrocarbons in anthropogenic dark earth of Amazonia (ADE and their biochar (BC. Functional diversity analyses in ADE soils can provide information on how adaptive microorganisms may influence the fertility of soils and what is their involvement in biogeochemical cycles. For this, clone libraries containing the gene encoding for the alpha subunit of aromatic ring-hydroxylating dioxygenases (α-ARHD bacterial gene were constructed, totaling 800 clones. These libraries were prepared from samples of an ADE soil under two different land uses, located at the Caldeirão Experimental Station - secondary forest (SF and agriculture (AG -, and the biochar (SF_BC and AG_BC, respectively. Heterogeneity estimates indicated greater diversity in BC libraries; and Venn diagrams showed more unique operational protein clusters (OPC in the SF_BC library than the ADE soil, which indicates that specific metabolic processes may occur in biochar. Phylogenetic analysis showed unidentified dioxygenases in ADE soils. Libraries containing functional gene encoding for the alpha subunit of the aromatic ring-hydroxylating dioxygenases (ARHD gene from biochar show higher diversity indices than those of ADE under secondary forest and agriculture.

  12. Ascorbate as a co-factor for fe- and 2-oxoglutarate dependent dioxygenases: physiological activity in tumor growth and progression.

    Science.gov (United States)

    Kuiper, Caroline; Vissers, Margreet C M

    2014-01-01

    Ascorbate is a specific co-factor for a large family of enzymes known as the Fe- and 2-oxoglutarate-dependent dioxygenases. These enzymes are found throughout biology and catalyze the addition of a hydroxyl group to various substrates. The proline hydroxylase that is involved in collagen maturation is well known, but in recent times many new enzymes and functions have been uncovered, including those involved in epigenetic control and hypoxia-inducible factor (HIF) regulation. These discoveries have provided crucial mechanistic insights into how ascorbate may affect tumor biology. In particular, there is growing evidence that HIF-1-dependent tumor progression may be inhibited by increasing tumor ascorbate levels. However, rigorous clinical intervention studies are lacking. This review will explore the physiological role of ascorbate as an enzyme co-factor and how this mechanism relates to cancer biology and treatment. The use of ascorbate in cancer should be informed by clinical studies based on such mechanistic hypotheses.

  13. Inflammation-induced activation of the indoleamine 2,3-dioxygenase pathway: Relevance to cancer-related fatigue.

    Science.gov (United States)

    Kim, Sangmi; Miller, Brian J; Stefanek, Michael E; Miller, Andrew H

    2015-07-01

    Cancer-related fatigue (CRF) is a common complication of cancer and its treatment that can significantly impair quality of life. Although the specific mechanisms remain poorly understood, inflammation is now considered to be a distinct component of CRF in addition to effects of depression, anxiety, insomnia, and other factors. One key biological pathway that may link inflammation and CRF is indoleamine 2,3-dioxygenase (IDO). Induced by inflammatory stimuli, IDO catabolizes tryptophan to kynurenine (KYN), which is subsequently converted into neuroactive metabolites. Here we summarize current knowledge concerning the relevance of the IDO pathway to CRF, including activation of the IDO pathway in cancer patients and, as a consequence, accumulation of neurotoxic KYN metabolites and depletion of serotonin in the brain. Because IDO inhibitors are already being evaluated as therapeutic agents in cancer, the elucidation of the relationship between IDO activation and CRF in cancer patients may lead to novel diagnostic and clinical approaches to managing CRF and its debilitating consequences.

  14. Characteristics and biotechnology applications of aliphatic amino acid hydroxylases belonging to the Fe(II)/α-ketoglutarate-dependent dioxygenase superfamily.

    Science.gov (United States)

    Hibi, Makoto; Ogawa, Jun

    2014-05-01

    The asymmetric hydroxylation of inactive carbon atoms is still an important reaction in the industrial synthesis of valuable chiral compounds such as pharmaceuticals and fine chemicals. Applications of monooxygenation enzymes, like cytochrome P450 monooxygenases, flavin-containing monooxygenases, and Fe(II)/α-ketoglutarate-dependent dioxygenases (Fe/αKG-DOs), are strongly desired as hydroxylation biocatalysts because they have great advantages in regio- and stereoselectivity of the reactions. Recently, several novel Fe/αKG-DOs have been found to catalyze the asymmetric hydroxylation of aliphatic amino acids. Depending on their amino acid sequences, these Fe/αKG-DOs catalyze different types of regioselective hydroxylations, or C3-, C4-, and C5-hydroxylation. Additionally, most also have stereoselective sulfoxidation activities. Here, we have reviewed the characterization and process development of this novel functioning group of Fe/αKG-DOs.

  15. 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.

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

    Directory of Open Access Journals (Sweden)

    A.S. Silva

    2013-01-01

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

  17. Novel biphenyl ester derivatives as tyrosinase inhibitors: Synthesis, crystallographic, spectral analysis and molecular docking studies

    Science.gov (United States)

    Kwong, Huey Chong; Chidan Kumar, C. S.; Mah, Siau Hui; Chia, Tze Shyang; Loh, Zi Han; Chandraju, Siddegowda; Lim, Gin Keat

    2017-01-01

    Biphenyl-based compounds are clinically important for the treatments of hypertension and inflammatory, while many more are under development for pharmaceutical uses. In the present study, a series of 2-([1,1'-biphenyl]-4-yl)-2-oxoethyl benzoates, 2(a-q), and 2-([1,1'-biphenyl]-4-yl)-2-oxoethyl pyridinecarboxylate, 2(r-s) were synthesized by reacting 1-([1,1'-biphenyl]-4-yl)-2-bromoethan-1-one with various carboxylic acids using potassium carbonate in dimethylformamide at ambient temperature. Single-crystal X-ray diffraction studies revealed a more closely packed crystal structure can be produced by introduction of biphenyl moiety. Five of the compounds among the reported series exhibited significant anti-tyrosinase activities, in which 2p, 2r and 2s displayed good inhibitions which are comparable to standard inhibitor kojic acid at concentrations of 100 and 250 μg/mL. The inhibitory effects of these active compounds were further confirmed by computational molecular docking studies and the results revealed the primary binding site is active-site entrance instead of inner copper binding site which acted as the secondary binding site. PMID:28241010

  18. Factors influencing combined exposure to three indicator polychlorinated biphenyls in an adult cohort from Bolivia.

    Science.gov (United States)

    Arrebola, J P; Mutch, E; Cuellar, M; Quevedo, M; Claure, E; Mejía, L M; Fernández-Rodríguez, M; Freire, C; Olea, N; Mercado, L A

    2012-07-01

    Polychlorinated biphenyls are persistent organic pollutants that have been used for decades in several industrial applications. Although production of polychlorinated biphenyls was restricted from the 1970s in most countries, substantial amounts remain in old equipment and buildings and they have been detected in various environmental and biological matrices. The main objective of this study was to analyze predictors of the combined exposure to three non-dioxin-like polychlorinated biphenyls (congeners 138, 153 and 180) in serum and adipose tissue from an adult cohort (n=112) living in the city of Santa Cruz de la Sierra (Bolivia) and surrounding towns/villages. A second aim was to identify modifiers that might influence the statistical associations found, using crude, partially-adjusted, and global multiple linear regression models. Main predictors of serum concentrations were occupation and fatty food consumption, while those for adipose tissue concentrations included age, smoking habit, fatty food consumption, and residence. The differences between the two matrices might be derived from their biological meaning, given that adipose tissue concentrations are an indicator of chronic exposure to polychlorinated biphenyls while serum levels are a good predictor of ongoing exposure and the mobilization of polychlorinated biphenyls stored in fatty tissues. Body mass index was found to be an important modifier of these associations.

  19. Polychlorinated biphenyls in Spanish adults: Determinants of serum concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Agudo, Antonio, E-mail: a.agudo@iconcologia.net [Unit of Nutrition, Environment, and Cancer, Cancer Epidemiology Research Program, Catalan Institute of Oncology (ICO), IDIBELL, Av. Gran Via no 199-203, 08907 L' Hospitalet de Llobregat (Spain); Goni, Fernando [Laboratorio de Salud Publica de Guipuzcoa, 20013 San Sebastian (Spain); CIBER Epidemiologia y Salud Publica (CIBERESP) (Spain); Etxeandia, Arsenio [Laboratorio de Salud Publica de Vizcaya, 48010 Bilbao (Spain); Vives, Asuncion [Laboratorio Unificado Donostia, Hospital N. S. Aranzazu, 20014 San Sebastian (Spain); Millan, Esmeralda [Departamento de Quimica Aplicada, Universidad del Pais Vasco, Facultad de Quimica, 20080 San Sebastian (Spain); Lopez, Raul [CIBER Epidemiologia y Salud Publica (CIBERESP) (Spain); Amiano, Pilar [CIBER Epidemiologia y Salud Publica (CIBERESP) (Spain); Direccion de Salud de Guipuzcoa, 20013 San Sebastian (Spain); Ardanaz, Eva; Barricarte, Aurelio [CIBER Epidemiologia y Salud Publica (CIBERESP) (Spain); Instituto de Salud Publica de Navarra, 31003 Pamplona (Spain); Dolores Chirlaque, M. [CIBER Epidemiologia y Salud Publica (CIBERESP) (Spain); Consejeria de Sanidad, 3008 Murcia (Spain); Dorronsoro, Miren [CIBER Epidemiologia y Salud Publica (CIBERESP) (Spain); Direccion de Salud de Guipuzcoa, 20013 San Sebastian (Spain); Jakszyn, Paula [Unit of Nutrition, Environment, and Cancer, Cancer Epidemiology Research Program, Catalan Institute of Oncology (ICO), IDIBELL, Av. Gran Via no 199-203, 08907 L' Hospitalet de Llobregat (Spain); Larranaga, Nerea [CIBER Epidemiologia y Salud Publica (CIBERESP) (Spain); Direccion de Salud de Guipuzcoa, 20013 San Sebastian (Spain); Martinez, Carmen [CIBER Epidemiologia y Salud Publica (CIBERESP) (Spain); Escuela Andaluza de Salud Publica, 18080 Granada (Spain); Navarro, Carmen [CIBER Epidemiologia y Salud Publica (CIBERESP) (Spain); Consejeria de Sanidad, 3008 Murcia (Spain); Rodriguez, Laudina [Consejeria de Salud y Servicios Sanitarios de Asturias, 33001 Oviedo (Spain); and others

    2009-07-15

    Background: Polychlorinated biphenyls (PCBs) are persistent compounds that may pose an environmental hazard to humans, food being the main source of exposure for the general population. Objective: To measure the serum concentrations of the main PCBs in subjects from the general population in Spain, and to assess potential determinants of such concentrations. Methods: Serum was obtained from blood samples of 953 subjects aged 35-64 years, residents in five Spanish regions (three from the North and two from the South), randomly selected from the EPIC-Spain cohort. Blood collection took place during 1992-1996 and four PCB congeners (118, 138, 153 and 180) were determined by means of gas chromatography with electron-capture detection (GC-ECD). Results: The concentration of total PCBs was 459 ng/g lipids (or 3.1 {mu}g/l); the corresponding figures for PCB 153 were 186 ng/g lipids and 1.25 {mu}g/l. Men had higher values than women, PCB levels increased with age, and serum concentration of PCBs was higher in northern regions. Body mass index (BMI) was inversely related to PCB concentrations, and fish intake was the dietary factor showing the greatest association with serum PCBs. The pattern described was similar for each congener separately. Conclusions: We found concentrations similar to those reported in European countries where blood collection was carried during the same period. Regional differences within Spain are not fully explained by anthropometric or dietary factors. The inverse association with BMI suggests that in the mid-1990s there was still ongoing or recent exposure to PCBs in Spain.

  20. Ecotoxicology of polychlorinated biphenyls in fish--a critical review.

    Science.gov (United States)

    Henry, T B

    2015-01-01

    Polychlorinated biphenyls (PCBs) are widespread persistent anthropogenic contaminants that can accumulate in tissues of fish. The toxicity of PCBs and their transformation products has been investigated for nearly 50 years, but there is a lack of consensus regarding the effects of these environmental contaminants on wild fish populations. The objective of this review is to critically examine these investigations and evaluate publicly available databases for evidence of effects of PCBs in wild fish. Biological activity of PCBs is limited to a small proportion of PCB congeners [e.g., dioxin-like PCBs (DL-PCBs)] and occurs at concentrations that are typically orders of magnitude higher than PCB levels detected in wild fish. Induction of biomarkers consistent with PCB exposure (e.g., induction of cytochrome P450 monooxygenase system) has been evaluated frequently and shown to be induced in fish from some environments, but there does not appear to be consistent reports of damage (i.e., biomarkers of effect) to biomolecules (i.e., oxidative injury) in these fish. Numerous investigations of endocrine system dysfunction or effects on other organ systems have been conducted in wild fish, but collectively there is no consistent evidence of PCB effects on these systems in wild fish. Early life stage toxicity of DL-PCBs does not appear to occur at concentrations reported in wild fish embryos, and results do not support an association between PCBs and decreased survival of early life stages of wild fish. Overall, there appears to be little evidence that PCBs have had any widespread effect on the health or survival of wild fish.

  1. Immunotoxicity Monitoring in a Population Exposed to Polychlorinated Biphenyls

    Directory of Open Access Journals (Sweden)

    Hajo Haase

    2016-03-01

    Full Text Available The relationship between polychlorinated biphenyl (PCB burden and several indicators of immune function was investigated as part of the HELPcB (Health Effects in High-Level Exposure to PCB program, offering bio-monitoring to workers, relatives, and neighbors exposed to PCBs by a German transformers and capacitors recycling company. The present retrospective observational study evaluates the correlation of plasma levels of total PCBs, five indicator congeners (28, 101, 138, 153, 180, and seven dioxin-like congeners (105, 114, 118, 156, 157, 167, 189 with several parameters of immune function. The cross-sectional study was performed immediately after the end of exposure (258 subjects, and one (218 subjects, and two (177 subjects years later. At the first time point, measurements showed significant positive correlation between congeners with low to medium chlorination and the relative proportion of CD19 positive B-cells among lymphocytes, as well as a negative correlation of PCB114 with serum IgM, and of PCB 28 with suppressor T-cell and NK-cell numbers. Congeners with a high degree of chlorination, in particular PCB157 and 189, were positively associated with expression of the activation marker CD25 on T-cells in the cohort of the second time point. No associations between PCB levels and IFN-y production by T-cells and killing by NK-cells were found. In conclusion, there were several effects on the cellular composition of adaptive immunity, affecting both T- and B-cells. However, the values were not generally outside the reference ranges for healthy adult individuals and did not indicate overt functional immunodeficiency, even in subjects with the uppermost PCB burden.

  2. Immunotoxicity Monitoring in a Population Exposed to Polychlorinated Biphenyls.

    Science.gov (United States)

    Haase, Hajo; Fahlenkamp, Astrid; Schettgen, Thomas; Esser, Andre; Gube, Monika; Ziegler, Patrick; Kraus, Thomas; Rink, Lothar

    2016-03-08

    The relationship between polychlorinated biphenyl (PCB) burden and several indicators of immune function was investigated as part of the HELPcB (Health Effects in High-Level Exposure to PCB) program, offering bio-monitoring to workers, relatives, and neighbors exposed to PCBs by a German transformers and capacitors recycling company. The present retrospective observational study evaluates the correlation of plasma levels of total PCBs, five indicator congeners (28, 101, 138, 153, 180), and seven dioxin-like congeners (105, 114, 118, 156, 157, 167, 189) with several parameters of immune function. The cross-sectional study was performed immediately after the end of exposure (258 subjects), and one (218 subjects), and two (177 subjects) years later. At the first time point, measurements showed significant positive correlation between congeners with low to medium chlorination and the relative proportion of CD19 positive B-cells among lymphocytes, as well as a negative correlation of PCB114 with serum IgM, and of PCB 28 with suppressor T-cell and NK-cell numbers. Congeners with a high degree of chlorination, in particular PCB157 and 189, were positively associated with expression of the activation marker CD25 on T-cells in the cohort of the second time point. No associations between PCB levels and IFN-y production by T-cells and killing by NK-cells were found. In conclusion, there were several effects on the cellular composition of adaptive immunity, affecting both T- and B-cells. However, the values were not generally outside the reference ranges for healthy adult individuals and did not indicate overt functional immunodeficiency, even in subjects with the uppermost PCB burden.

  3. Spermaturia and serum hormone concentrations at the age of puberty in boys prenatally exposed to polychlorinated biphenyls

    DEFF Research Database (Denmark)

    Mol, Nanette M; Sørensen, Nicolina; Weihe, Pal;

    2002-01-01

    To determine whether prenatal exposure to polychlorinated biphenyls (PCBs) with possible hormone-disrupting effects is capable of affecting sexual differentiation in boys at the age of puberty.......To determine whether prenatal exposure to polychlorinated biphenyls (PCBs) with possible hormone-disrupting effects is capable of affecting sexual differentiation in boys at the age of puberty....

  4. Molecular Descriptors Family on Structure Activity Relationships 6. Octanol-Water Partition Coefficient of Polychlorinated Biphenyls

    Directory of Open Access Journals (Sweden)

    Lorentz JÄNTSCHI

    2006-01-01

    Full Text Available Octanol-water partition coefficient of two hundred and six polychlorinated biphenyls was model by the use of an original method based on complex information obtained from compounds structure. The regression analysis shows that best results are obtained in four-varied model (r2 = 0.9168. The prediction ability of the model was studied through leave-one-out analysis (r2cv(loo = 0.9093 and in training and test sets analysis. Modeling the octanol-water partition coefficient of polychlorinated biphenyls by integration of complex structural information provide a stable and performing four-varied model, allowing us to make remarks about relationship between structure of polychlorinated biphenyls and associated octanol-water partition coefficients.

  5. 2,2,6,6-Tetrakis(biphenyl-2-yl-4,4,8,8-tetramethylcyclotetrasiloxane

    Directory of Open Access Journals (Sweden)

    Erik P. A. Couzijn

    2009-09-01

    Full Text Available The title compound, [–Si(C12H92OSi(CH32O–]2, was obtained unintentionally as the product of an attempted crystallization of caesium bis(biphenyl-2,2′-diylfluorosilicate from dimethylformamide. In the crystal, the molecule is located on an inversion center and the siloxane ring adopts a twist-chair conformation with the two dimethyl-substituted Si atoms lying 0.7081 (5 Å out of the plane defined by the two bis(biphenyl-2-yl-substituted Si atoms and the four O atoms. In each Si(C12H92 unit, the orientation of one terminal phenyl ring relative to the phenylene ring of the other biphenyl moiety suggests a parallel displaced π–π stacking interaction [centroid distance = 4.2377 (11 Å and dihedral angle = 15.40 (9°].

  6. 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

  7. Occurrence, distribution, and dechlorination of polychlorinated biphenyls and health risk assessment in Selangor River basin.

    Science.gov (United States)

    Sakai, Nobumitsu; Dayana, Emmy; Abu Bakar, Azizi; Yoneda, Minoru; Nik Sulaiman, Nik Meriam; Ali Mohd, Mustafa

    2016-10-01

    Polychlorinated biphenyls (PCBs) were monitored in surface water collected in the Selangor River basin, Malaysia, to identify the occurrence, distribution, and dechlorination process as well as to assess the potential adverse effects to the Malaysian population. Ten PCB homologs (i.e., mono-CBs to deca-CBs) were quantitated by using gas chromatography-mass spectrometry (GC/MS). The total concentration of PCBs in the 10 sampling sites ranged from limit of detection to 7.67 ng L(-1). The higher chlorinated biphenyls (tetra-CBs to deca-CBs) were almost not detected in most of the sampling sites, whereas lower chlorinated biphenyls (mono-CBs, di-CBs, and tri-CBs) dominated more than 90 % of the 10 homologs in all the sampling sites. Therefore, the PCB load was estimated to be negligible during the sampling period because PCBs have an extremely long half-life. The PCBs, particularly higher chlorinated biphenyls, could be thoroughly dechlorinated to mono-CBs to tri-CBs by microbial decomposition in sediment or could still be accumulated in the sediment. The lower chlorinated biphenyls, however, could be resuspended or desorbed from the sediment because they have faster desorption rates and higher solubility, compared to the higher chlorinated biphenyls. The health risk for the Malaysia population by PCB intake that was estimated from the local fish consumption (7.2 ng kg(-1) bw day(-1)) and tap water consumption (1.5 × 10(-3)-3.1 × 10(-3) ng kg(-1) bw day(-1)) based on the detected PCB levels in the surface water was considered to be minimal. The hazard quotient based on the tolerable daily intake (20 ng kg(-1) bw day(-1)) was estimated at 0.36.

  8. Biodegradation of pyrene and catabolic genes in contaminated soils cultivated with Lolium multiflorum L

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Sardar [Dept. of Environmental Sciences, Univ. of Preshawar (Pakistan); Hesham, Abd El-Latif [Genetics Dept., Faculty of Agriculture, Assiut Univ. (Egypt); Qing Gu; Shuang Liu; He Jizheng [Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences (China)

    2009-10-15

    Background, aim, and scope In the soil environment, polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs) are of great environmental and human health concerns due to their widespread occurrence, persistence, and carcinogenic properties. Bioremediation of contaminated soil is a cost-effective, environmentally friendly, and publicly acceptable approach to address the removal of environmental contaminants. However, biore-mediation of contaminants depends on plant-microbe interactions in the rhizosphere. The microorganisms that can mineralize various PAHs have PAH dioxygenase genes like nahAc, phnAc, and pdol. To understand the fate of pyrene in rhizospheric and non-rhizospheric soils in the presence or absence of Pb, pyrene biodegradation, bacterial community structure, and dioxygenase genes were investigated in a pot experiment. (orig.)

  9. Synthesis and Characterization of Nonsymmetric Liquid Crystal Dimer Containing Biphenyl and Azobenzene Moiety

    Directory of Open Access Journals (Sweden)

    S. Sandy Subala

    2013-01-01

    Full Text Available Calamitic liquid crystalline dimer containing azobenzene moiety and a decyloxy biphenyl linked by flexible spacers {4-[7-(4′-decyloxy-biphenyl-4-yloxy-alkyloxy]-phenyl}-(4-decyl-phenyl-diazene has been synthesized and characterized by spectroscopic methods. The transition temperatures and phase behaviours were studied by Differential Scanning Calorimeter (DSC and Polarizing Optical Microscope (POM. The synthesized compounds exhibited enantiotropic liquid crystal phase with higher spacer display nematic and smectic C phases while lower spacer shows nematic and smectic A phases.

  10. Crystal Structure and Mechanism of Tryptophan 2,3-Dioxygenase, a Heme Enzyme Involved in Tryptophan Catabolism and in Quinolinate Biosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Zhang,Y.; Kang, S.; Mukherjee, T.; Bale, S.; Crane, B.; Begley, T.; Ealick, S.

    2007-01-01

    The structure of tryptophan 2,3-dioxygenase (TDO) from Ralstonia metallidurans was determined at 2.4 {angstrom}. TDO catalyzes the irreversible oxidation of L-tryptophan to N-formyl kynurenine, which is the initial step in tryptophan catabolism. TDO is a heme-containing enzyme and is highly specific for its substrate L-tryptophan. The structure is a tetramer with a heme cofactor bound at each active site. The monomeric fold, as well as the heme binding site, is similar to that of the large domain of indoleamine 2,3-dioxygenase, an enzyme that catalyzes the same reaction except with a broader substrate tolerance. Modeling of the putative (S)-tryptophan hydroperoxide intermediate into the active site, as well as substrate analogue and mutagenesis studies, are consistent with a Criegee mechanism for the reaction.

  11. Blockage of indoleamine 2,3-dioxygenase regulates Japanese encephalitis via enhancement of type I/II IFN innate and adaptive T-cell responses

    OpenAIRE

    2016-01-01

    Background Japanese encephalitis (JE), a leading cause of viral encephalitis, is characterized by extensive neuroinflammation following infection with neurotropic JE virus (JEV). Indoleamine 2,3-dioxygenase (IDO) has been identified as an enzyme associated with immunoregulatory function. Although the regulatory role of IDO in viral replication has been postulated, the in vivo role of IDO activity has not been fully addressed in neurotropic virus-caused encephalitis. Methods Mice in which IDO ...

  12. A murine model for type III tyrosinemia: lack of immunologically detectable 4-hydroxyphenylpyruvic acid dioxygenase enzyme protein in a novel mouse strain with hypertyrosinemia.

    Science.gov (United States)

    Endo, F; Katoh, H; Yamamoto, S; Matsuda, I

    1991-04-01

    We have characterized a new mutant strain of mouse that has hypertyrosinemia. The blood tyrosine level was persistently high, and increased amounts of 4-hydroxyphenylpyruvic acid and its derivatives were excreted into the urine. Succinylacetone was not detected in urine samples from these mice. All the animals were apparently healthy, and there was no evidence of hepatorenal dysfunction. The hypertyrosinemia was transmitted through an autosomal recessive inheritance. Analyses of hepatic enzymes related to tyrosine metabolism revealed that 4-hydroxyphenylpyruvic acid dioxygenase activity was virtually absent, while fumarylacetoacetase and tyrosine aminotransferases (cytosolic and mitochondrial forms) were normal in these mutant mice. Immunoblot analysis of 4-hydroxyphenylpyruvic acid dioxygenase protein in the liver indicated that the subunit protein of the enzyme was absent. It would appear that hypertyrosinemia in this mutant strain was caused by a genetic defect in 4-hydroxyphenylpyruvic acid dioxygenase. These features are similar to type III tyrosinemia in humans. Analysis of this mutant strain of mouse is expected to provide valuable information on the pathogenesis of human type III tyrosinemia and can also serve as a useful system for studies on tyrosine metabolism.

  13. The mitochondrial sulfur dioxygenase ETHYLMALONIC ENCEPHALOPATHY PROTEIN1 is required for amino acid catabolism during carbohydrate starvation and embryo development in Arabidopsis.

    Science.gov (United States)

    Krüßel, Lena; Junemann, Johannes; Wirtz, Markus; Birke, Hannah; Thornton, Jeremy D; Browning, Luke W; Poschet, Gernot; Hell, Rüdiger; Balk, Janneke; Braun, Hans-Peter; Hildebrandt, Tatjana M

    2014-05-01

    The sulfur dioxygenase ETHYLMALONIC ENCEPHALOPATHY PROTEIN1 (ETHE1) catalyzes the oxidation of persulfides in the mitochondrial matrix and is essential for early embryo development in Arabidopsis (Arabidopsis thaliana). We investigated the biochemical and physiological functions of ETHE1 in plant metabolism using recombinant Arabidopsis ETHE1 and three transfer DNA insertion lines with 50% to 99% decreased sulfur dioxygenase activity. Our results identified a new mitochondrial pathway catalyzing the detoxification of reduced sulfur species derived from cysteine catabolism by oxidation to thiosulfate. Knockdown of the sulfur dioxygenase impaired embryo development and produced phenotypes of starvation-induced chlorosis during short-day growth conditions and extended darkness, indicating that ETHE1 has a key function in situations of high protein turnover, such as seed production and the use of amino acids as alternative respiratory substrates during carbohydrate starvation. The amino acid profile of mutant plants was similar to that caused by defects in the electron-transfer flavoprotein/electron-transfer flavoprotein:ubiquinone oxidoreductase complex and associated dehydrogenases. Thus, in addition to sulfur amino acid catabolism, ETHE1 also affects the oxidation of branched-chain amino acids and lysine.

  14. Plasma polychlorinated biphenyl concentrations and immune function in postmenopausal women

    Energy Technology Data Exchange (ETDEWEB)

    Spector, June T., E-mail: spectj@uw.edu [Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, 4225 Roosevelt Way NE, Seattle, WA 98105 (United States); Department of Medicine, School of Medicine, University of Washington, Seattle, WA (United States); De Roos, Anneclaire J., E-mail: ajd335@drexel.edu [Epidemiology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N, P.O. Box 19024, Seattle, WA 98109 (United States); Department of Epidemiology, School of Public Health, University of Washington, Seattle, WA (United States); Ulrich, Cornelia M., E-mail: neli.ulrich@nct-heidelberg.de [Department of Epidemiology, School of Public Health, University of Washington, Seattle, WA (United States); Cancer Prevention Program, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N, P.O. Box 19024, Seattle, WA 98109 (United States); National Center for Tumor Diseases and German Cancer Research Center, Heidelberg (Germany); Sheppard, Lianne, E-mail: sheppard@uw.edu [Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, 4225 Roosevelt Way NE, Seattle, WA 98105 (United States); Department of Biostatistics, School of Public Health, University of Washington, Seattle, WA (United States); Sjoedin, Andreas, E-mail: asjodin@cdc.gov [National Center for Environmental Health, CDC, 4770 Buford Highway NE, Atlanta, GA 30341 (United States); Wener, Mark H., E-mail: wener@u.washington.edu [Department of Medicine, School of Medicine, University of Washington, Seattle, WA (United States); Wood, Brent, E-mail: woodbl@u.washington.edu [Department of Medicine, School of Medicine, University of Washington, Seattle, WA (United States); and others

    2014-05-01

    Background: Polychlorinated biphenyl (PCB) exposure has been associated with non-Hodgkin lymphoma in several studies, and the immune system is a potential mediator. Objectives: We analyzed associations of plasma PCBs with immune function measures. We hypothesized that higher plasma PCB concentrations are associated with lower immune function cross-sectionally, and that increases in PCB concentrations over a one year period are associated with decreases in immune function. Methods: Plasma PCB concentrations and immune function [natural killer (NK) cell cytotoxicity and PHA-induced T-lymphocyte proliferation (PHA-TLP)] were measured at baseline and one year in 109 postmenopausal overweight women participating in an exercise intervention study in the Seattle, Washington (USA) area. Mixed models, with adjustment for body mass index and other potential confounders, were used to estimate associations of PCBs with immune function cross-sectionally and longitudinally. Results: Associations of PCBs with immune function measures differed across groups of PCBs (e.g., medium- and high-chlorinated and dioxin-like [mono-ortho-substituted]) and by the time frame for the comparison (cross-sectional vs. longitudinal). Higher concentrations of medium- and high-chlorinated PCBs were associated with higher PHA-TLP cross-sectionally but not longitudinally. The mean decrease in 0.5 µg/mL PHA-TLP/50.0 pmol/g-lipid increase in dioxin-like PCBs over one year was 51.6 (95% confidence interval 2.7, 100.5; P=0.039). There was no association between plasma PCBs and NK cytotoxicity. Conclusions: These results do not provide strong evidence of impaired cellular immunity from PCB exposure. Larger longitudinal studies with greater variability in PCB exposures are needed to further examine temporal associations of PCBs with immune function. - Highlights: • Plasma PCBs and immune function were measured in 109 women at baseline and one year. • Immune measures included T lymphocyte proliferation

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

    Science.gov (United States)

    Hjortsø, Mads Duus; Larsen, Stine Kiaer; Kongsted, Per; Met, Özcan; Frøsig, Thomas Mørch; Andersen, Gitte Holmen; Ahmad, Shamaila Munir; Svane, Inge Marie; Becker, Jürgen C; Straten, Per thor; Andersen, Mads Hald

    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 to TDO-derived MHC-class II restricted peptides. Hence, in healthy donors (HD) a Th1 helper response was predominant, whereas in cancer patients CD4+ T-cell responses were skewed toward a regulatory T cell (Treg) response. Furthermore, MM patients hosting a TDO-specific IL-17 response showed a trend toward an improved overall survival (OS) compared to MM patients with IL-10 producing, TDO-reactive CD4+ T cells. For further characterization, we isolated and expanded both CD8+ and CD4+ TDO-reactive T cells in vitro. TDO-reactive CD8+ T cells were able to kill HLA-matched tumor cells of different origin. Interestingly, the processed and presented TDO-derived epitopes varied between different cancer cells. With respect to CD4+ TDO-reactive T cells, in vitro expanded T-cell cultures comprised a Th1 and/or a Treg phenotype. In summary, our data demonstrate that the immune modulating enzyme TDO is a target for CD8+ and CD4+ T cell responses both in healthy subjects as well as patients with cancer; notably, however, the functional phenotype of these T-cell responses differ

  16. Polychlorinated biphenyls-induced alterations of thyroid hormone homeostasis and brain development in the rat.

    NARCIS (Netherlands)

    Morse, D.C.

    1995-01-01

    IntroductionThe work described in this thesis was undertaken to gain insight in the processes involved in the developmental neurotoxicity of polychlorinated biphenyls. It has been previously hypothesized that the alteration of thyroid hormone status by PCBs may be in part responsibl

  17. ANALYSIS OF CHIRAL PESTICIDES AND POLYCHLORINATED BIPHENYL CONGENERS IN ENVIRONMENTAL SAMPLES

    Science.gov (United States)

    Over 25 % of pesticides and other toxic organic pollutants are chiral, as are 19 of the 209 polychlorinated biphenyl (PCB) congeners; that is, they exist as two mirror image species called enantiomers (PCB enantiomers are called atropisomers). The enantiomers of a chiral compound...

  18. Biphenyl Phytoalexin in Sorbus pohuashanensis Suspension Cell Induced by Yeast Extract.

    Science.gov (United States)

    Zhou, Liangyun; Yang, Jian; Yang, Guang; Kang, Chuanzhi; Xiao, Wenjuan; Lv, Chaogeng; Wang, Sheng; Tang, Jinfu; Guo, Lanping

    2016-09-14

    Biphenyls are unique phytoalexins de novo synthesized in plants in response to pathogen attack. These compounds are found in Maloideae, a subfamily of the Rosaceae. The anti-microbial activities of biphenyls have been reported in a number of studies and they appear to represent an important defense strategy against pathogens common in the Maloideae, such as species in Malus, Pyrus, Sorbus, and Chaenomeles. Here, cell suspension cultures of Sorbus pohuashanensis were established to study biphenyl phytoalexins formation after yeast extract (YE) treatment. An ultra-performance liquid chromatography (UPLC) method coupled with quadrupole time of flight mass spectrometry (Q-TOF-MS) LC-MS/MS was applied to determine the time course of these biphenyl biomarkers accumulation in YE-treated S. pohuashanensis suspension cells. The results of quantitative analyses show the content of Noraucuparin, 2'-Hydroxyaucuparin, and their glycosides initially increased, then decreased over time. The Noraucuparin content reached its highest (225.76 μg·g(-1)) at 18 h after treatment, 6 hours earlier than that of Noraucuparin 5-O-β-d-glucopyranoside. The content of 2'-Hydroxyaucuparin reached its highest (422.75 μg·g(-1)) at 30 h after treatment, also earlier than that of its glycoside. The understanding of phytoalexin metabolism in this study may provide a basis for improving Maloideae resistance to pathogens.

  19. Biphenyl Phytoalexin in Sorbus pohuashanensis Suspension Cell Induced by Yeast Extract

    Directory of Open Access Journals (Sweden)

    Liangyun Zhou

    2016-09-01

    Full Text Available Biphenyls are unique phytoalexins de novo synthesized in plants in response to pathogen attack. These compounds are found in Maloideae, a subfamily of the Rosaceae. The anti-microbial activities of biphenyls have been reported in a number of studies and they appear to represent an important defense strategy against pathogens common in the Maloideae, such as species in Malus, Pyrus, Sorbus, and Chaenomeles. Here, cell suspension cultures of Sorbus pohuashanensis were established to study biphenyl phytoalexins formation after yeast extract (YE treatment. An ultra-performance liquid chromatography (UPLC method coupled with quadrupole time of flight mass spectrometry (Q-TOF-MS LC−MS/MS was applied to determine the time course of these biphenyl biomarkers accumulation in YE-treated S. pohuashanensis suspension cells. The results of quantitative analyses show the content of Noraucuparin, 2′-Hydroxyaucuparin, and their glycosides initially increased, then decreased over time. The Noraucuparin content reached its highest (225.76 μg·g−1 at 18 h after treatment, 6 hours earlier than that of Noraucuparin 5-O-β-d-glucopyranoside. The content of 2′-Hydroxyaucuparin reached its highest (422.75 μg·g−1 at 30 h after treatment, also earlier than that of its glycoside. The understanding of phytoalexin metabolism in this study may provide a basis for improving Maloideae resistance to pathogens.

  20. Differential effect of elicitors on biphenyl and dibenzofuran formation in Sorbus aucuparia cell cultures.

    Science.gov (United States)

    Hüttner, Cornelia; Beuerle, Till; Scharnhop, Helge; Ernst, Ludger; Beerhues, Ludger

    2010-11-24

    The Rosaceous subtribe Pyrinae (formerly subfamily Maloideae) is well-known for its economically important fruit trees, such as apple and pear, and also includes Sorbus aucuparia. Elicitor-treated S. aucuparia cell cultures are used to study the biosynthesis of the Pyrinae-specific phytoalexins, biphenyls and dibenzofurans. Three biphenyls (aucuparin, noraucuparin, 2'-hydroxyaucuparin) and a dibenzofuran (eriobofuran) were isolated and structure elucidated using GC-MS and NMR. A second dibenzofuran of low abundance was tentatively assigned as noreriobofuran. Treatment of S. aucuparia cell cultures with yeast extract induced the formation of aucuparin as the major phytoalexin. In contrast, addition of preparations from the fire blight bacterium, Erwinia amylovora, and the scab-causing fungus, Venturia inaequalis, resulted in accumulation of eriobofuran as the major inducible constituent. Methyl jasmonate was a poor elicitor. The observations are suggestive of a biogenic relationship between biphenyls and dibenzofurans. Elicitor-treated S. aucuparia cell cultures provide an interesting in vitro system for studying biphenyl and dibenzofuran metabolism in the economically valuable Pyrinae.

  1. Dermal toxicity studies of technical polychlorinated biphenyls and fractions thereof in rabbits

    NARCIS (Netherlands)

    Vos, J.G.; Beems, R.B.

    1971-01-01

    A significant difference in toxicity between 3 polychlorinated biphenyl (PCB) preparations was found in a prior study: Clophen A 60 and Phenoclor DP6 showing the highest, Aroclor 1260 the lowest, toxicity (Vos and Koeman, 1970). A subsequent study revealed the presence of tetra- and pentachlorodiben

  2. EFFECTS OF POLYCHLORINATED-BIPHENYLS (PCBS) AND DIOXINS ON GROWTH AND DEVELOPMENT

    NARCIS (Netherlands)

    SAUER, PJJ; HUISMAN, M; KOOPMANESSEBOOM, C; MORSE, DC; SMITSVANPROOIJE, AE; VANDEBERG, KJ; TUINSTRA, LGMT; VANDERPAAUW, CG; BOERSMA, ER; WEISGLASKUPERUS, N; LAMMERS, JHCM; KULIG, BM; BROUWER, A

    1994-01-01

    Polychlorinated biphenyls (PCBs) and dioxins are potentially toxic compounds which occur widely in the environment. Their effects on the growth and development of infants at the levels currently found in highly industrialised western countries is not well known. This Dutch multicenter study, combini

  3. ESTIMATION OF GIBBS FREE-ENERGIES OF FORMATION FOR POLYCHLORINATED-BIPHENYLS

    NARCIS (Netherlands)

    HOLMES, DA; HARRISON, BK; DOLFING, J

    1993-01-01

    Gibbs free energies of formation for gas, subcooled liquid, and aqueous solution phases were estimated for all 209 polychlorinated biphenyl (PCB) congeners at 298.15 K and 100 000 Pa. A literature search was conducted to locate experimental data or predicted data for PCBs. Where other data were not

  4. An efficient synthesis, X-ray and spectral characterization of biphenyl derivatives

    Indian Academy of Sciences (India)

    Ravindra R Kamble; Dharesh B Biradar; Gangadhar Y Meti; Tasneem Taj; Tegginamath Gireesh; Imthiyaz Ahmed M Khazi; Sundar T Vaidyanathan; Raju Mohandoss; Balasubramanian Sridhar; Viraraghav Parthasarathi

    2011-07-01

    Derivatives of 1,3-thiazolidin-2,4-dione appended to biphenyl ring viz., 7-9, 16-18 were prepared. The newly synthesized compounds were confirmed by IR, NMR (1H and 13C) MS and elemental analyses. Single crystal X-ray diffraction study was carried out for one of the final compounds 9.

  5. New Biochemical Pathway for Biphenyl Degradation in Plants: Structural, Mechanistic and Biotechnological Aspects

    Energy Technology Data Exchange (ETDEWEB)

    Pacios, L. F.; Campos, V. M.; Merino, I.; Gomez, L.

    2009-07-01

    Polychlorinated biphenyls (PVBs) and other structurally-related xenobiotics are amongst the most relevant organic pollutants known today. while some bacterial species can metabolize PCBs, with varying efficiency, no catabolic pathways have yet been described in plants. This is so despite the great potential of (at least some) plant species for soil and groundwater decontamination, a technology known as phyto remediation. (Author)

  6. Immunologic effects of background exposure to polychlorinated biphenyls and dioxins in Dutch preschool children

    NARCIS (Netherlands)

    Weisglas-Kuperus, N; Patandin, S; Berbers, GAM; Sas, TCJ; Mulder, PGH; Sauer, PJJ; Hooijkaas, H

    2000-01-01

    Prenatal exposure to polychlorinated biphenyls (PCBs) and dioxins is associated with changes in the T-cell lymphocyte population in healthy Dutch infants. We investigated whether these changes persist into later childhood and whether background exposure to PCBs and dioxins is associated with the pre

  7. Determination of Polychlorinated Biphenyls in Soil and Sediment by Selective Pressurized Liquid Extraction with Immunochemical Detection

    Science.gov (United States)

    A selective liquid pressurized extraction (SPLE) method was developed as a streamlined sample preparation/cleanup procedure for determining Aroclors and coplanar polychlorinated biphenyls (PCBs) in soil and sediment matrices. The SPLE method was coupled with an enzyme-linked imm...

  8. Polychlorinated biphenyls in adipose tissue, liver, and brain from nine stillborns of varying gestational ages

    NARCIS (Netherlands)

    Huisman, M; Muskiet, FAJ; Van Der Paauw, CG; Essed, CE; Boersma, ER

    1998-01-01

    We analyzed polychlorinated biphenyls (PCBs) in s.c. adipose tissue, liver, and brain of nine fetuses who died in utero. Their median (range) gestational ages and birth weights were 34 (17-40) wk and 2050 (162-3225) g. Three fetuses were small for gestational age. The levels of PCB congener nos. 118

  9. Polychlorinated biphenyls alter expression of alpha-synuclein, synaptophysin and parkin in the rat brain

    DEFF Research Database (Denmark)

    Malkiewicz, Katarzyna; Mohammed, Roma; Folkesson, Ronnie;

    2006-01-01

    Polychlorinated Biphenyls (PCBs)-induced changes in synaptic transmission are one of the effects of their neurotoxicity but the mechanism remains unknown. We assessed the in vivo effects of the PCBs mixture, Aroclor 1254 on the expression of neuronal proteins that are involved in the synaptic...

  10. A method for the chemical modification of polychlorinated biphenyls for improved affinity towards noble metal surfaces

    DEFF Research Database (Denmark)

    2015-01-01

    The present application discloses a method for the modification and analysis of a field sample suspected of containing contaminant(s) like polychlorinated biphenyls (PCBs). The invention also relates to a corresponding kit for the modification of samples suspected of containing such contaminant(s)....

  11. Synthesis and properties of a new diarylethene having thiazole and biphenyl moieties

    Energy Technology Data Exchange (ETDEWEB)

    Li Hui; Pu Shouzhi; Liu Gang; Liu Weijun, E-mail: pushouzhi@tsinghua.org.cn [Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, Nanchang 330013 (China)

    2011-02-01

    A novel photochromic diarylethene bearing thiazole and biphenyl moieties has been synthesized. Its properties, including photochromism and fluorescence were investigated in detail. It underwent reversible cyclization and cycloreversion reactions upon alternating irradiation with UV and visible light in hexane. The results showed that this compound exhibited reversible photochromism and good fluorescent switching in solution after irradiation with UV light and visible light.

  12. Effects of sedimentary soot-like materials on bioaccumulation and sorption of polychlorinated biphenyls

    NARCIS (Netherlands)

    Jonker, M.T.O.; Hoenderboom, A.M.; Koelmans, A.A.

    2004-01-01

    Bioaccumulation of hydrophobic organic chemicals from sediments containing soot or sootlike materials has been hypothesized to be limited by strong sorption of the chemicals to the soot matrixes. To test this hypothesis, we quantified bioaccumulation of 11 polychlorinated biphenyls (PCBs) into the a

  13. The occurrence and significance of polychlorinated biphenyls in the environment

    Science.gov (United States)

    Dustman, E.H.; Stickel, L.F.; Blus, L.J.; Reichel, W.L.; Wiemeyer, Stanley N.

    1971-01-01

    SUMMARY: Polychlorinated biphenyls constitute a group of chlorine-bearing compounds of industrial origin that have permeated the natural environment throughout the world. Their chemical structure resembles that of some of the organochlorine pesticides. They are troublesome interferences in gas chromatographic analysis of these pesticides. Although methods have been developed to overcome analytical problems, measurements of quantity still are only approximate. Special studies in the United States, Netherlands, and Great Britain have traced PCB's to industrial effluent, but other possible sources have not been followed. Their use in paints, cartons, and insulating fluids suggests that environmental pollution may be from many different sources. PCB's are present in fish and wildlife in many countries of the world. Quantities are higher in animals living near industrial areas. PCB's build up in biological food chains with increases of tens to thousands of times from lower to higher organisms. Experimental studies have shown that PCB's have a toxicity to mallards, pheasants, bobwhite quail, coturnix quail, red-winged blackbirds, starlings, cowbirds, and grackles that is of the same order as the toxicity of DDE to these species. Overt signs of poisoning also are similar to those caused by compounds of the DDT group. Toxic effects of DDE and Aroclor 1254 to coturnix chicks were additive, but not synergistic. PCB's containing higher percentages of chlorine are more toxic to birds than those containing lower percentages. PCB's of foreign manufacture contained contaminants to an extent that greatly increased their toxicity Aroclor 1242. Statistical evaluations of the role that different chemicals may play in thinning of eggshells of brown pelicans show that DDE residues correlate better with shell thinning than do residues of dieldrin or PCB's. Studies of the effects of PCB's in the environment are as yet insufficient for well-rounded conclusions. The evidence available

  14. Unity in diversity, a systems approach to regulating plant cell physiology by 2-oxoglutarate-dependent dioxygenases.

    Science.gov (United States)

    Kundu, Siddhartha

    2015-01-01

    Could a disjoint group of enzymes synchronize their activities and execute a complex multi-step, measurable, and reproducible response? Here, I surmise that the alpha-ketoglutarate dependent superfamily of non-haem iron (II) dioxygenases could influence cell physiology as a cohesive unit, and that the broad spectra of substrates transformed is an absolute necessity to this portrayal. This eclectic group comprises members from all major taxa, and participates in pesticide breakdown, hypoxia signaling, and osmotic stress neutralization. The oxidative decarboxylation of 2-oxoglutarate to succinate is coupled with a concomitant substrate hydroxylation and, in most cases, is followed by an additional specialized conversion. The domain profile of a protein sequence was used as an index of miscellaneous reaction chemistry and interpreted alongside existent kinetic data in a linear model of integrated function. Statistical parameters were inferred by the creation of a novel, empirically motivated flat-file database of over 3800 sequences (DB2OG) with putative 2-oxoglutarate dependent activity. The collated information was categorized on the basis of existing annotation schema. The data suggests that 2OG-dependent enzymes incorporate several desirable features of a systems level player. DB2OG, is free, accessible without a login to all users, and available at the following URL (http://comp-biol.theacms.in/DB2OG.html).

  15. 4-hydroxyphenylpyruvate dioxygenase catalysis: identification of catalytic residues and production of a hydroxylated intermediate shared with a structurally unrelated enzyme.

    Science.gov (United States)

    Raspail, Corinne; Graindorge, Matthieu; Moreau, Yohann; Crouzy, Serge; Lefèbvre, Bertrand; Robin, Adeline Y; Dumas, Renaud; Matringe, Michel

    2011-07-22

    4-Hydroxyphenylpyruvate dioxygenase (HPPD) catalyzes the conversion of 4-hydroxyphenylpyruvate (HPP) into homogentisate. HPPD is the molecular target of very effective synthetic herbicides. HPPD inhibitors may also be useful in treating life-threatening tyrosinemia type I and are currently in trials for treatment of Parkinson disease. The reaction mechanism of this key enzyme in both plants and animals has not yet been fully elucidated. In this study, using site-directed mutagenesis supported by quantum mechanical/molecular mechanical theoretical calculations, we investigated the role of catalytic residues potentially interacting with the substrate/intermediates. These results highlight the following: (i) the central role of Gln-272, Gln-286, and Gln-358 in HPP binding and the first nucleophilic attack; (ii) the important movement of the aromatic ring of HPP during the reaction, and (iii) the key role played by Asn-261 and Ser-246 in C1 hydroxylation and the final ortho-rearrangement steps (numbering according to the Arabidopsis HPPD crystal structure 1SQD). Furthermore, this study reveals that the last step of the catalytic reaction, the 1,2 shift of the acetate side chain, which was believed to be unique to the HPPD activity, is also catalyzed by a structurally unrelated enzyme.

  16. Reaction mechanism of homoprotocatechuate 2,3-dioxygenase with 4-nitrocatechol: implications for the role of substrate.

    Science.gov (United States)

    Dong, Geng; Lai, Wenzhen

    2014-02-20

    The reaction mechanism of the dioxygen activation by homoprotocatechuate 2,3-dioxygenase (HPCD) with the substrate 4-nitrocatechol was investigated by quantum mechanical/molecular mechanical calculations. Our results demonstrated that the experimentally determined side-on iron-oxygen complex in crystallo is a semiquinone substrate radical (SQ(•))-Fe(III)-hydroperoxo species, which could not act as the reactive species. In fact, the Fe(III)-superoxo species with a hydrogen bond between His200 and the proximal oxygen is the reactive oxygen species. The second-sphere His200 residue was found to play an important role in manipulating the orientation of the superoxide in the Fe-O2 adduct for the further reaction. The rate-limiting step is the attack of the superoxo group on the substrate with a barrier of 17.2 kcal/mol, in good agreement with the experimental value of 16.8 kcal/mol. The reaction mechanism was then compared with the one for HPCD with its native substrate homoprotocatechuate studied recently by the same methods, in which a hybrid SQ(•)-Fe(II)-O2(•-)/Fe(III)-O2(•-) was suggested to be the reactive species. Therefore, our studies suggested that the substrate plays important roles in the dioxygen activation by HPCD.

  17. Scavenging properties of neutrophil 4-hydroxyphenylpyruvate dioxygenase are based on a hypothesis that does not stand up to scrutiny.

    Science.gov (United States)

    Salerno, Costantino; Zicari, Alessandra; Mari, Emanuela; D'Eufemia, Patrizia

    2014-10-01

    It was previously reported by D'Eufemia et al. [9] that neutrophil preparations from a patient with tyrosinemia type III, i.e. with inherited deficiency of 4-hydroxyphenylpyruvate dioxygenase (HPPD), exhibited a far higher NO release than controls, when NO was estimated in terms of nitrite content in the suspending media. It was hypothesized that HPPD might participate to NO sequestration in neutrophils and that excessive NO release might reflect the lack of the scavenging action in defective cells. In recent control experiments, we found that HPPD activity in neutrophils preparations from healthy subjects is below the detection limit of the enzymatic assay (less than 3nmol product/h per mg protein). This indicates that HPPD concentration in neutrophils is very low, if any, confirming what was already suggested in literature, and rules out the possibility of a prominent role of HPPD as NO scavenger in these cells. Moreover, we found that 500μM l-tyrosine increases nitrite release and accumulation in suspending media of U-937 cells, a human monoblast-like lymphoma cell line which displays many characteristics of macrophages, including the expression of inducible and endothelial nitric oxide synthases. We hypothesize that the increase of nitrite release by patient's neutrophils might be related to the presence of high l-tyrosine concentrations in the blood samples (426μmol/L instead of 52.1±10.9μmol/L as healthy subjects), rather than to HPPD deficiency of in these cells.

  18. Triterpenoids isolated from the rhizomes and roots of Gentiana scabra and their inhibition of indoleamine 2,3-dioxygenase.

    Science.gov (United States)

    Li, Wei; Li, Lin Ying; Zhou, Wei; Hwang, Inkyu; Ma, Jin Yeul; Kim, Young Ho

    2015-12-01

    Gentiana scabra Bunge (Gentianaceae) is an important traditional Chinese medicine commonly used as a stomachic or appetite stimulant. In this study, 21 triterpenoids (1-21) were isolated from a methanol extract of the rhizomes and roots of G. scabra. Their structures were elucidated by comparing spectroscopic data with reported values. Among the isolated triterpenoids, scabanol (2) was firstly isolated from natural sources. All isolated compounds were evaluated for their inhibitory activity against indoleamine 2,3-dioxygenase (IDO), which catalyzes the rate limiting reaction for the conversion of tryptophan to kynurenine. Compounds 10 and 11 showed significant inhibitory activities, with IC(50) values of 12.5 and 9.5 μM, respectively. Compound 12 showed a moderate inhibitory effect, with an IC(50) value of 18.7 μM. Compounds 2 and 13 showed weaker inhibitory effects, with IC(50) values of 56.8 and 60.6 μM, respectively. Kynurenine is a potent immune modulator to suppress the functions of a variety of immune cells including T cells and natural killer cells. Given that, our results that a few selected triterpenoids inhibit IDO warrant further studies on their effects on the host immune system as natural immune stimulators.

  19. 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; Lee, Pyung Cheon

    2013-06-01

    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-13 C-14, C-15 C-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.

  20. Diazotization of kynurenine by acidified nitrite secreted from indoleamine 2,3-dioxygenase-expressing myeloid dendritic cells.

    Science.gov (United States)

    Hara, Toshiaki; Yamakura, Fumiyuki; Takikawa, Osamu; Hiramatsu, Rie; Kawabe, Tsutomu; Isobe, Ken-Ichi; Nagase, Fumihiko

    2008-03-20

    Indoleamine 2,3-dioxygenase (IDO)-initiated tryptophan metabolism along the kynurenine (Kyn) pathway regulates T-cell responses in some dendritic cells (DC) such as plasmacytoid DC. A Kyn assay using HPLC showed that samples were frequently deproteinized with trichloroacetic acid (TCA). In the present study, bone marrow-derived myeloid DC (BMDC) were differentiated from mouse bone marrow cells with GM-CSF. CpG oligodeoxynucleotides (CpG) induced the expression of IDO protein with NO production in BMDC cultured for 24 h. The concentrations of Kyn in the culture supernatants were not increased by stimulation with CpG but rather decreased by based on the Kyn assay after deproteinization with TCA. The level of Kyn exogenously added into the cell-free culture supernatant of BMDC stimulated with CpG was severely decreased by deproteinization with TCA but not methanol, and the decrease was prevented when BMDC was stimulated with CpG in the presence of a NOS inhibitor. Under acidic conditions, Kyn reacted with nitrite produced by BMDC, and generated a new compound that was not detected by Ehrlich reagent reacting with the aromatic amino residue of Kyn. An analysis by mass spectrometry showed the new compound to be a diazotization form of Kyn. In conclusion, the deproteinization of samples by acidic treatment should be avoided for the Kyn assay when NO is produced.

  1. Relationship of Abortion and the Expression of Indoleamine 2,3- dioxygenase (IDO) in Villus and Syncytiotrophoblasts

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Objective To study the relationship of abortion and the expression of indoleamine 2,3- dioxygenase (IDO) in villus and syncytiotrophoblast in vitro.Methods RT-PCR was applied to analyze the mRNA transcription of IDO in villus of normal pregnancy and inevitable abortion and JAR cells as well. Immunohistochemistry was applied to analyze the expression of IDO protein in villus. Western blot was applied to determinate the expression of IDO protein on cultured syncytiotrophoblast. Highperformance liquid chromatography was applied to determinate whether there was kynurenine in cell culture medium of syncytiotrophoblast.Results The expression of IDO mRNA and protein in villus of inevitable abortion was lower than that of normal pregnancy; IDO mRNA did not express in JAR cells. IDO protein expressed on cultured syncytiotrophoblast, and there was kynurenine in cell culture medium of syncytiotrophoblast.Conclusion Appropriate expression of IDO in villus is necessary for maintenance of normal pregnancy and an active IDO protein expresses in syncytiotrophoblast.

  2. 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.

  3. Proof of concept for the use of macroinvertebrates as indicators of polychlorinated biphenyls (PCB) contamination in Lake Hartwell

    Science.gov (United States)

    The U.S. Environmental Protection Agency (EPA) has been conducting research to develop methods and tools for the evaluation of monitored natural recovery (MNR) of sediments contaminated with polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and other lega...

  4. Mixed function oxidase dependent biotransformation of polychlorinated biphenyls by different species of fish from the North Sea

    DEFF Research Database (Denmark)

    Mehrtens, G.; Laturnus, F.

    1999-01-01

    Mixed function oxidase (MFO) dependent biotransformation of polychlorinated biphenyls (PCBs) was measured in three different fish species from the North Sea. Liver microsomes of plaice (Pleuronectes platessa), dab (Limanda limanda) and cod (Gadus morhua) were isolated and incubated with different...

  5. 丹参2-酮戊二酸依赖性双加氧酶基因克隆及表达分析%Cloning and Expression Analysis of 2-oxoglutarate-dependent Dioxygenase from Salvia miltiorrhiza Bunge

    Institute of Scientific and Technical Information of China (English)

    刘文超; 王东浩; 王喆之; 李翠芹

    2012-01-01

    以商洛紫花丹参为材料,对其转录组序列SRA020132进行Blast分析,采用PCR技术克隆得到丹参2-酮戊二酸依赖性双加氧酶基因Sm2-ODD1,GenBank登录号为JN935923.Sm2-ODD1基因全长1365 bp,包含3个外显子和2个内含子;cDNA全长1189 bp,读码框951 bp,编码316个氨基酸残基;预测的编码蛋白具有2-酮戊二酸依赖性双加氧酶中结合2-酮戊二酸和亚铁离子的“H-T-D”、“H-X”和“R-Y-S”保守基序以及“果冻状”空间结构.表达分析显示,Sm2-ODD1在丹参各个器官都表达,但表达水平具有组织特异性,在根中表达量最高,在叶中表达量最低;该基因表达明显受到MeJA、GA3和ABA的诱导,可能参与了丹参萜类代谢下游途径.%By analyzing Transcriptome (SRA020132) sequences of Salvia miltiorrhiza from Shangluo and using the techniques of PCR,a new 2-oxoglutarate-dependent dioxygenase gene was cloned from Salvia miltiorrhiza for the first time and named as Sm2-ODD1 (GenBank accession number JN935923). SmZ-ODD1 DNA consisted of 1 365 bp including 3 exons and 2 introns. The full-length cDNA of Sm2-ODDl was 1 189 bp, containing a single 951 bp opening reading frame and encoding a 316 amino-acid residues. Bioinformatics analysis showed that SmZ-ODD1 contained a 2-oxoglutarate-dependent dioxygenase super-family containing "distorted jelly roll" domain and "H-T-D","H-X" and "R-Y-S" motifs to bind 2-oxoglut-arate and Fe2+. Quantitative RT-PCR analysis revealed that the gene expressed in different organs. The expression in roots was observably higher than in flowers, stems and leaves. The gene could be induced by methyl jasmonate,GA3 and ABA. The results indicated that the Sm2-ODDl might be involved in the biosynthesis of terpene in Salvia miltiorrhiza.

  6. Evaluating the biodegradation of aromatic hydrocarbons by monitoring of several functional genes.

    Science.gov (United States)

    Piskonen, Reetta; Nyyssönen, Mari; Itävaara, Merja

    2008-11-01

    Various microbial activities determine the effectiveness of bioremediation processes. In this work, we evaluated the feasibility of gene array hybridization for monitoring the efficiency of biodegradation processes. Biodegradation of 14C-labelled naphthalene and toluene by the aromatic hydrocarbon-degrading Pseudomonas putida F1, P. putida mt-2 and P. putida G7 was followed in mixed liquid culture microcosm by a preliminary, nylon membrane-based gene array. In the beginning of the study, toluene was degraded rapidly and increased amount of toluene degradation genes was detected by the preliminary gene array developed for the study. After toluene was degraded, naphthalene mineralization started and the amount of naphthalene degradation genes increased as biodegradation proceeded. The amount of toluene degradation genes decreased towards the end of the study. The hybridization signal intensities determined by preliminary gene array were in good agreement with mineralization of naphthalene and toluene and with the amount of naphthalene dioxygenase and toluene dioxygenase genes quantified by dot blot hybridization. The clear correlation between the results obtained by the preliminary array and the biodegradation process suggests that gene array methods can be considered as a promising tool for monitoring the efficiency of biodegradation processes.

  7. The Ternary Complex of PrnB (the Second Enzyme in the Pyrrolnitrin Biosynthesis Pathway), Tryptophan, and Cyanide Yields New Mechanistic Insights into the Indolamine Dioxygenase Superfamily*

    Science.gov (United States)

    Zhu, Xiaofeng; van Pée, Karl-Heinz; Naismith, James H.

    2010-01-01

    Pyrrolnitrin (3-chloro-4-(2′-nitro-3′-chlorophenyl)pyrrole) is a broad-spectrum antifungal compound isolated from Pseudomonas pyrrocinia. Four enzymes (PrnA, PrnB, PrnC, and PrnD) are required for pyrrolnitrin biosynthesis from tryptophan. PrnB rearranges the indole ring of 7-Cl-l-tryptophan and eliminates the carboxylate group. PrnB shows robust activity in vivo, but in vitro activity for PrnB under defined conditions remains undetected. The structure of PrnB establishes that the enzyme belongs to the heme b-dependent indoleamine 2,3-dioxygenase (IDO) and tryptophan 2,3-dioxygenase (TDO) family. We report the cyanide complex of PrnB and two ternary complexes with both l-tryptophan or 7-Cl-l-tryptophan and cyanide. The latter two complexes are essentially identical and mimic the likely catalytic ternary complex that occurs during turnover. In the cyanide ternary complexes, a loop previously disordered becomes ordered, contributing to the binding of substrates. The conformations of the bound tryptophan substrates are changed from that seen previously in the binary complexes. In l-tryptophan ternary complex, the indole ring now adopts the same orientation as seen in the PrnB binary complexes with other tryptophan substrates. The amide and carboxylate group of the substrate are orientated in a new conformation. Tyr321 and Ser332 play a key role in binding these groups. The structures suggest that catalysis requires an l-configured substrate. Isothermal titration calorimetry data suggest d-tryptophan does not bind after cyanide (or oxygen) coordinates with the distal (or sixth) site of heme. This is the first ternary complex with a tryptophan substrate of a member of the tryptophan dioxygenase superfamily and has mechanistic implications. PMID:20421301

  8. Structural Basis for Substrate and Oxygen Activation in Homoprotocatechuate 2,3-Dioxygenase: Roles of Conserved Active Site Histidine-200

    Science.gov (United States)

    Kovaleva, Elena G.; Rogers, Melanie S.; Lipscomb, John D.

    2015-01-01

    Kinetic and spectroscopic studies have shown that the conserved active site residue His200 of the extradiol ring-cleaving homoprotocatechuate 2,3-dioxygenase (FeHPCD) from Brevibacterium fuscum is critical for efficient catalysis. The roles played by this residue are probed here by analysis of the steady state kinetics, pH dependence, and X-ray crystal structures of the FeHPCD position 200 variants His200Asn, His200Gln, and His200Glu alone and in complex with three catecholic substrates (homoprotocatechuate, 4-sulfonylcatechol, and 4-nitrocatechol) possessing substituents with different inductive capacity. Structures solved at 1.35 –1.75 Å resolution show that there is essentially no change in overall active site architecture or substrate binding mode for these variants when compared to the structures of the wild type enzyme and its analogous complexes. This shows that the maximal 50-fold decrease in kcat for ring cleavage, the dramatic changes in pH dependence, and the switch from ring cleavage to ring oxidation of 4-nitrocatechol by the FeHPCD variants can be attributed specifically to the properties of the altered second sphere residue and the substrate. The results suggest that proton transfer is necessary for catalysis, and that it occurs most efficiently when the substrate provides the proton and His200 serves as a catalyst. However, in the absence of an available substrate proton, a defined proton-transfer pathway in the protein can be utilized. Changes in steric bulk and charge of the residue at position 200 appear capable of altering the rate-limiting step in catalysis, and perhaps, the nature of the reactive species. PMID:26267790

  9. Structural Basis for Substrate and Oxygen Activation in Homoprotocatechuate 2,3-Dioxygenase: Roles of Conserved Active Site Histidine 200.

    Science.gov (United States)

    Kovaleva, Elena G; Rogers, Melanie S; Lipscomb, John D

    2015-09-01

    Kinetic and spectroscopic studies have shown that the conserved active site residue His200 of the extradiol ring-cleaving homoprotocatechuate 2,3-dioxygenase (FeHPCD) from Brevibacterium fuscum is critical for efficient catalysis. The roles played by this residue are probed here by analysis of the steady-state kinetics, pH dependence, and X-ray crystal structures of the FeHPCD position 200 variants His200Asn, His200Gln, and His200Glu alone and in complex with three catecholic substrates (homoprotocatechuate, 4-sulfonylcatechol, and 4-nitrocatechol) possessing substituents with different inductive capacity. Structures determined at 1.35-1.75 Å resolution show that there is essentially no change in overall active site architecture or substrate binding mode for these variants when compared to the structures of the wild-type enzyme and its analogous complexes. This shows that the maximal 50-fold decrease in kcat for ring cleavage, the dramatic changes in pH dependence, and the switch from ring cleavage to ring oxidation of 4-nitrocatechol by the FeHPCD variants can be attributed specifically to the properties of the altered second-sphere residue and the substrate. The results suggest that proton transfer is necessary for catalysis, and that it occurs most efficiently when the substrate provides the proton and His200 serves as a catalyst. However, in the absence of an available substrate proton, a defined proton-transfer pathway in the protein can be utilized. Changes in the steric bulk and charge of the residue at position 200 appear to be capable of altering the rate-limiting step in catalysis and, perhaps, the nature of the reactive species.

  10. High activity of indoleamine 2,3 dioxygenase enzyme predicts disease severity and case fatality in bacteremic patients.

    Science.gov (United States)

    Huttunen, Reetta; Syrjänen, Jaana; Aittoniemi, Janne; Oja, Simo S; Raitala, Annika; Laine, Janne; Pertovaara, Marja; Vuento, Risto; Huhtala, Heini; Hurme, Mikko

    2010-02-01

    Indoleamine 2,3-dioxygenase (IDO), which is the rate-limiting enzyme for tryptophan (trp) catabolism, may play a critical role in various inflammatory disorders. Recent studies on trauma patients have suggested that the degradation of trp is associated with the development of sepsis. The role of IDO activity in bacteremic patients is unclear. We studied IDO activity in 132 patients with bacteremia caused by Staphylococcus aureus, Streptococcus pneumoniae, beta-hemolytic streptococcae, or Eschericia coli. The serum concentrations of trp and its metabolite kynurenine (kyn) were measured by reverse-phase high-performance liquid chromatography 1 to 4 days after the positive blood culture and on recovery. The kyn-to-trp ratio (kyn/trp), reflecting the activity of the IDO enzyme, was calculated. The maximum value in the ratio for every patient during 1 to 4 days after positive blood culture was used in analysis. The maximum kyn/trp ratio was significantly higher in nonsurvivors versus those who survived (193.7 vs. 82.4 micromol/mmol; P = 0.001). The AUC(ROC) of maximal kyn/trp in the prediction of case fatality was 0.75 (95% confidence interval, 0.64-0.87), and the kyn/trp ratio at a cutoff level of 120 micromol/mmol showed 83% sensitivity and 69% specificity for fatal disease. A kyn/trp ratio greater than 120 micromol/mmol was associated with increased risk of death versus low (

  11. The cystine/glutamate antiporter regulates indoleamine 2,3-dioxygenase protein levels and enzymatic activity in human dendritic cells.

    Science.gov (United States)

    Mattox, Mildred L; D'Angelo, June A; Grimes, Zachary M; Fiebiger, Edda; Dickinson, Bonny L

    2012-11-30

    Indoleamine 2,3-dioxygenase (IDO) is the rate-limiting enzyme in the tryptophan-catabolizing pathway and a key regulator of peripheral immune tolerance. As the suppressive effects of IDO are predominantly mediated by dendritic cells (DCs) and IDO-competent DCs promote long-term immunologic tolerance, a detailed understanding of how IDO expression and activity is regulated in these cells is central to the rational design of therapies to induce robust immune tolerance. We previously reported that the cystine/glutamate antiporter modulates the functional expression of IDO in human monocyte-derived DCs. Specifically, we showed that blocking antiporter uptake of cystine significantly increased both IDO mRNA and IDO enzymatic activity and that this correlated with impaired DC presentation of exogenous antigen to T cells via MHC class II and the cross-presentation pathway. The antiporter regulates intracellular and extracellular redox by transporting cystine into the cell in exchange for glutamate. Intracellular cystine is reduced to cysteine to support biosynthesis of the major cellular antioxidant glutathione and cysteine is exported from the cell where it functions as an extracellular antioxidant. Here we show that antiporter control of IDO expression in DCs is reversible, independent of interferon-γ, regulated by redox, and requires active protein synthesis. These findings highlight a role for antiporter regulation of cellular redox as a critical control point for modulating IDO expression and activity in DCs. Thus, systemic disease and aging, processes that perturb redox homeostasis, may adversely affect immunity by promoting the generation of IDO-competent DCs.

  12. Respiratory Syncytial Virus-Infected Mesenchymal Stem Cells Regulate Immunity via Interferon Beta and Indoleamine-2,3-Dioxygenase

    Science.gov (United States)

    Cheung, Michael B.; Sampayo-Escobar, Viviana; Green, Ryan; Moore, Martin L.; Mohapatra, Subhra; Mohapatra, Shyam S.

    2016-01-01

    Respiratory syncytial virus (RSV) has been reported to infect human mesenchymal stem cells (MSCs) but the consequences are poorly understood. MSCs are present in nearly every organ including the nasal mucosa and the lung and play a role in regulating immune responses and mediating tissue repair. We sought to determine whether RSV infection of MSCs enhances their immune regulatory functions and contributes to RSV-associated lung disease. RSV was shown to replicate in human MSCs by fluorescence microscopy, plaque assay, and expression of RSV transcripts. RSV-infected MSCs showed differentially altered expression of cytokines and chemokines such as IL-1β, IL6, IL-8 and SDF-1 compared to epithelial cells. Notably, RSV-infected MSCs exhibited significantly increased expression of IFN-β (~100-fold) and indoleamine-2,3-dioxygenase (IDO) (~70-fold) than in mock-infected MSCs. IDO was identified in cytosolic protein of infected cells by Western blots and enzymatic activity was detected by tryptophan catabolism assay. Treatment of PBMCs with culture supernatants from RSV-infected MSCs reduced their proliferation in a dose dependent manner. This effect on PBMC activation was reversed by treatment of MSCs with the IDO inhibitors 1-methyltryptophan and vitamin K3 during RSV infection, a result we confirmed by CRISPR/Cas9-mediated knockout of IDO in MSCs. Neutralizing IFN-β prevented IDO expression and activity. Treatment of MSCs with an endosomal TLR inhibitor, as well as a specific inhibitor of the TLR3/dsRNA complex, prevented IFN-β and IDO expression. Together, these results suggest that RSV infection of MSCs alters their immune regulatory function by upregulating IFN-β and IDO, affecting immune cell proliferation, which may account for the lack of protective RSV immunity and for chronicity of RSV-associated lung diseases such as asthma and COPD. PMID:27695127

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

    Directory of Open Access Journals (Sweden)

    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.

  14. Quercetin ameliorates polychlorinated biphenyls-induced testicular DNA damage in rats.

    Science.gov (United States)

    Lovato, F L; de Oliveira, C R; Adedara, I A; Barbisan, F; Moreira, K L S; Dalberto, M; da Rocha, M I U M; Marroni, N P; da Cruz, I B; Costabeber, I B

    2016-02-01

    Polychlorinated biphenyls (PCBs) are a group of environmental contaminants widely reported to cause gonadal toxicity in both humans and animals. This study investigated the amelioratory role of quercetin in PCBs-induced DNA damage in male Wistar rats. Polychlorinated biphenyls were administered intraperitoneally at a dose of 2 mg kg(-1) alone or in combination with quercetin (orally) at 50 mg kg(-1) for 25 days. Quercetin modulation of PCBs-induced gonadal toxicity was evaluated using selected oxidative stress indices, comet assay, measurement of DNA concentration and histology of the testes. Administration of PCBs alone caused a significant (P Quercetin cotreatment significantly improved the testicular antioxidant status, decreased DNA fragmentation and restored the testicular histology, thus demonstrating the protective effect of quercetin in PCBs-treated rats.

  15. Synthesis and biological evaluation of nitric oxide-releasing sixalkoxyl biphenyl derivatives as anticancer agents

    Institute of Scientific and Technical Information of China (English)

    Xiang Wen Kong; Yi Hua Zhang; Li Dai; Hui Ji; Yi Sheng Lai; Si Xun Peng

    2008-01-01

    A series of novel nitric oxide-donating sixalkoxyl biphenyl derivatives (14a-i)were synthesized by coupling furoxan with alkoxyl biphenyl skeleton using amino acids as the spacers,and their cytotoxicity against HepG2 cells in vitro were evaluated by MTr method.It was found that 14c,14d,14f,14i,14j and 14k showed more potent cytotoxic activities than control 5-fluorouracil.NO release assay of target compounds indicated that the maximum amount of NO released by most active compounds 14c and 14j was about 6 x 10-2μmol/L,whereas 14a and 14h with very weak activity only released NO of 1 x 10-μmol/L.

  16. Reducing ulcerogenic potential of biphenyl acetic acid: Design and development of chimeric derivatives with amino acids

    Directory of Open Access Journals (Sweden)

    Suneela Dhaneshwar

    2016-09-01

    Full Text Available In an attempt to minimize the ulcerogenic potential and associated gastro-intestinal toxicity of bioprecursor fenbufen and its active metabolite biphenyl acetic acid, carrier-linked chimeric derivatives of the latter were designed and synthesized using amino acids as the promoities. DCC coupling method was used for the synthesis of these amides. The chimeras were characterized by IR and 1H NMR. Pharmacological investigations were carried out in animal models for analgesic, anti-inflammatory, anti-arthritic and ulcerogenic activities. The chimeras exhibited high gastro-sparing effect; quick onset and longer duration of analgesia; enhanced/prolonged anti-inflammatory activity and better anti-arthritic effect than fenbufen or biphenyl acetic acid. These derivatives could be useful as a chronotherapy for rheumatoid arthritis due to their prolonged analgesic and anti-inflammatory effects.

  17. Luminescent properties and photostability of thin films of N,N'-phenyl-substituted biphenyls

    Science.gov (United States)

    Chaplanova, Zh. D.; Mikhailovskii, Yu. K.; Agabekov, V. E.; Galinovskii, N. A.; Gracheva, E. A.

    2012-11-01

    We have studied the luminescent properties and morphology of thin films, formed by deposition from solutions (wet) and thermal vacuum deposition (TVD), of 4,4'- bis[(E)-2-[4-(diphenylamino)phenyl]ethenyl]-1,1'-biphenyl (PAB-1) and its 2-oxyhexyl derivative (PAB-2). We have established that the presence of an oxyhexyl side substituent in the structure of N,N'-phenyl-substituted biphenyl promotes quenching of the photoluminescence of the TVD film based on it when stored in air. We show that introducing PAB-2 into a polymer matrix (polymethylmethacrylate, polystyrene, polycyclohexadiene) significantly improves the stability of such composite films when exposed to UV light and to oxygen in the air. We use electron diffraction and atomic force microscopy to establish that these films have an amorphous structure that remains resistant to degradation during photooxidative aging.

  18. Food contamination with polychlorinated biphenyls and dioxins in Belgium. Effects on the body burden.

    Science.gov (United States)

    Van Larebeke, N; Covaci, A; Schepens, P; Hens, L

    2002-11-01

    The core paper of this debate shows that persistent organic pollutant residues of the 12 chemicals targeted for a phase out under the Stockholm Convention are present in almost all categories of food in the US food supply. For dioxins, the study does not use measured data, but is based upon potential dioxin residues in selected food items. Polychlorinated biphenyls are not included in the study. In this paper we discuss selected data of polychlorinated biphenyl and dioxin concentrations in Belgian food. Some of these exposures are chronic, others are attributable to incidents. Both result in high body burdens in Belgium. The paper also compares the current concentrations in food with the recent standards launched by the EU for dioxins in food, and discusses whether these values adequately protect European citizens.

  19. Dechlorination of polychlorinated biphenyl-contaminated soil via anaerobic composting with pig manure.

    Science.gov (United States)

    Zhang, Chi; Du, Yao; Tao, Xiao-Qing; Zhang, Kun; Shen, Dong-Sheng; Long, Yu-Yang

    2013-10-15

    Anaerobic dechlorination is an effective degradation pathway of higher chlorinated polychlorinated biphenyls (PCBs). The efficiency of anaerobic composting remediation of PCB-contaminated soil using pig manure was determined. The results show that the dechlorination of PCB-contaminated soil via anaerobic composting with pig manure is feasible. PCB concentration is the most critical factor. Elevated PCB concentrations can inhibit dechlorination but does not disrupt the anaerobic fermentation process. At 1 mg kg(-1) PCBs, the degradation rate of five or more chlorinated biphenyls is 43.8%. The highest dechlorination performance in this experiment was obtained when the soil-to-organic waste ratio, carbon-to-nitrogen ratio, moisture content, and PCB concentration were 2:3, 20, 60%, and 1 mg kg(-1), respectively.

  20. A practical approach to the degradation of polychlorinated biphenyls in transformer oil.

    Science.gov (United States)

    Wu, Wenhai; Xu, Jie; Zhao, Hongmei; Zhang, Qing; Liao, Shijian

    2005-08-01

    A practical and efficient disposal method for hydrodechlorination of polychlorinated biphenyls (PCBs) in transformer oil is reported. Transformer oil containing PCBs was treated by nanometric sodium hydride (nano-NaH) and transition metal catalysts. High destruction and removal efficiency (89.8%) can be attained by nano-NaH alone under mild conditions. The process exhibits apparent characteristics of a first order reaction. The reductive ability of nano-NaH was enhanced by the addition of transition metal catalysts. In the presence of TiCl4, 99.9% PCBs was hydrodechlorinated. The complex reducing reagents, Ni(OAc)2+i-PrONa, show extra hydrodechlorinating activity for di-chlorinated biphenyls.

  1. Impact of Polychlorinated Biphenyls Contamination on Estrogenic Activity in Human Male Serum

    OpenAIRE

    Plíšková, Martina; Vondráček, Jan; Canton, Rocio Fernandez; Nera, Jiřií; Kočan, Anton; Petrík, Ján; Trnovec, Tomáš; Sanderson, Thomas; van den Berg, Martin; Machala, Miroslav

    2005-01-01

    Polychlorinated biphenyls (PCBs) are thought to cause numerous adverse health effects, but their impact on estrogen signaling is still not fully understood. In the present study, we used the ER-CALUX bioassay to determine estrogenic/antiestrogenic activities of the prevalent PCB congeners and PCB mixtures isolated from human male serum. The samples were collected from residents of an area with an extensive environmental contamination from a former PCB production site as well as from a neighbo...

  2. Polychlorinated biphenyl hazards to fish, wildlife, and invertebrates: a synoptic review

    Energy Technology Data Exchange (ETDEWEB)

    Eisler, R.

    1986-04-01

    Entirely as a result of human activities, polychlorinated biphenyls (PCBs) are now distributed worldwide, with measurable concentrations recorded in fishery and wildlife resources from numerous and disparate locations. PCBs elicit a variety of biologic effects including death, birth defects, tumors, and a wasting syndrome. The account summarizes the recent technical literature on the environmental chemistry of PCBs, lists PCB background concentrations in fish, wildlife, and invertebrates; documents their toxic and sublethal properties; and reviews and provides recommendations for the protection of sensitive species.

  3. CLOSURE REPORT FOR CORRECTIVE ACTION UNIT 528: POLYCHLORINATED BIPHENYLS CONTAMINATION NEVADA TEST SITE, NEVADA

    Energy Technology Data Exchange (ETDEWEB)

    BECHTEL NEVADA

    2006-09-01

    This Closure Report (CR) describes the closure activities performed at CAU 528, Polychlorinated Biphenyls Contamination, as presented in the Nevada Division of Environmental Protection (NDEP)-approved Corrective Action Plan (CAP) (US. Department of Energy, National Nuclear Security Administration Nevada Site Office [NNSAINSO], 2005). The approved closure alternative was closure in place with administrative controls. This CR provides a summary of the completed closure activities, documentation of waste disposal, and analytical data to confirm that the remediation goals were met.

  4. Congener specific distribution and health risk assessment of polychlorinated biphenyls in urban soils

    OpenAIRE

    Bhupander Kumar; Sanjay Kumar; Chandra Shekhar Sharma

    2012-01-01

    Polychlorinated biphenyls (PCBs) were primarily used in transformers and capacitors, lubricants, flame retardants, plasticizers, paint, carbonless papers, etc. These are capable of long-range atmospheric transport and have been designated as persistent organic pollutants by the Stockholm Convention. Due to their characteristic properties, PCBs are found worldwide in all environmental matrices (including human) and biota. Soils are usually considered to be the source as well as sink for enviro...

  5. Polychlorinated biphenyls fractioning assessment in aqueous bioremediation assy with phanerochaete chrysosporium

    OpenAIRE

    2009-01-01

    Thanks to growing environmental concerns in public opinion, bioremediation processes are more and more used to decontaminate soils from organic compounds. Polychlorinated biphenyls (PCBs) are known to be world wide spread persistent organic pollutants (POPs). The white rot fungus Phanerochaete chrysosporium is able to degrade PCBs in water, and soil As POPs, PCBs can also be adsorbed onto organic matter, such as Phanerochaete chrysosporium mycelium. This study aims at estimating the fractioni...

  6. Relationships of Thyroid Hormones with Polychlorinated Biphenyls, Dioxins, Furans, and DDE in Adults

    OpenAIRE

    Turyk, Mary E.; Anderson, Henry A.; Persky, Victoria W.

    2007-01-01

    Background Thyroid hormone homeostasis can be disrupted by exposure to ubiquitous and bioaccumulative organochlorines such as polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins (PCDDs). Whereas investigations of health effects have generally focused on human populations with relatively high exposures through occupation, accident, or high fish consumption, general population exposures may also carry risk. Methods We studied associations of total thyroxine (T4) and thyroid-s...

  7. Polychlorinated Biphenyl-Xenobiotic Nuclear Receptor Interactions Regulate Energy Metabolism, Behavior, and Inflammation in Non-alcoholic-Steatohepatitis.

    Science.gov (United States)

    Wahlang, Banrida; Prough, Russell A; Falkner, K Cameron; Hardesty, Josiah E; Song, Ming; Clair, Heather B; Clark, Barbara J; States, J Christopher; Arteel, Gavin E; Cave, Matthew C

    2016-02-01

    Polychlorinated biphenyls (PCBs) are environmental pollutants associated with non-alcoholic-steatohepatitis (NASH), diabetes, and obesity. We previously demonstrated that the PCB mixture, Aroclor 1260, induced steatohepatitis and activated nuclear receptors in a diet-induced obesity mouse model. This study aims to evaluate PCB interactions with the pregnane-xenobiotic receptor (Pxr: Nr1i2) and constitutive androstane receptor (Car: Nr1i3) in NASH. Wild type C57Bl/6 (WT), Pxr(-/-) and Car(-/-) mice were fed the high fat diet (42% milk fat) and exposed to a single dose of Aroclor 1260 (20 mg/kg) in this 12-week study. Metabolic phenotyping and analysis of serum, liver, and adipose was performed. Steatohepatitis was pathologically similar in all Aroclor-exposed groups, while Pxr(-/-) mice displayed higher basal pro-inflammatory cytokine levels. Pxr repressed Car expression as evident by increased basal Car/Cyp2b10 expression in Pxr(-/-) mice. Both Pxr(-/-) and Car(-/-) mice showed decreased basal respiratory exchange rate (RER) consistent with preferential lipid metabolism. Aroclor increased RER and carbohydrate metabolism, associated with increased light cycle activity in both knockouts, and decreased food consumption in the Car(-/-) mice. Aroclor exposure improved insulin sensitivity in WT mice but not glucose tolerance. The Aroclor-exposed, Pxr(-/-) mice displayed increased gluconeogenic gene expression. Lipid-oxidative gene expression was higher in WT and Pxr(-/-) mice although RER was not changed, suggesting PCB-mediated mitochondrial dysfunction. Therefore, Pxr and Car regulated inflammation, behavior, and energy metabolism in PCB-mediated NASH. Future studies should address the 'off-target' effects of PCBs in steatohepatitis.

  8. Biphenyl metabolism by rat liver microsomes. Regioselective effects of inducers, inhibitors, and solvents

    Energy Technology Data Exchange (ETDEWEB)

    Haugen, D.A.

    1981-01-01

    The effects of the inducers phenobarbital and 3-methylcholanthrene, the inhibitors 7,8-benzoflavone and 1-benzyl-imidazole, and the solvents methanol, acetone, and dimethyl sulfoxide on the 2-, 3-, and 4-hydroxylation of biphenyl and the O-de-ethylation of 7-ethoxycoumarin by rat liver microsomes were examined. Phenobarbital pretreatment primarily induced 2- and 3-hydroxylation, the latter most dramatically. 3-Methylcholanthrene pretreatment induced 2- and 3-hydroxylation to similar extents. The inhibitors and solvents had regioselective effects on biphenyl metabolism that were characteristic of the uninduced, phenobarbital-induced, and 3-methylcholanthrene-induced microsomes. The presence of multiple forms of cytochrome P-450 in uninduced microsomes is indicated by the regioselective effects of the solvents and the inhibitors. The 3-methylcholanthrene-dependent increases in 2- and 3-hydroxylation appear due to induction of a single form of cytochrome P-450, as indicated by similar dose-response relationships and similar changes in sensitivitty to the inhibitors. The phenobarbital-dependent increases in 2- and 3-hydroxylation appear due to the induction of two forms of cytochrome P-450, as indicated by different changes in sensitivity to the effects of dimethyl sulfoxide and 7,8-benzoflavone. The results indicate that examination of the regioselectivity of biphenyl metabolism is a useful approach for characterizing microsomal mono-oxygenases, and they suggest that the approach may also be useful in the characterization of purified mono-oxygenase systems. (JMT)

  9. Polychlorinated biphenyls in eggs and chlorioallantoic membranes of American alligators (Alligator mississippiensis) from coastal South Carolina

    Energy Technology Data Exchange (ETDEWEB)

    Cobb, G.P.; Wood, P.D. [Clemson Univ., Pendleton, SC (United States); O`Quinn, M. [South Carolina Governor`s School for Science and Mathematics, Hartsville, SC (United States)

    1997-07-01

    Assessing chemical exposure in threatened or endangered wildlife species presents unique analytical problems. Chorioallantoic membranes (CAMs) have been proposed as surrogate tissues for evaluation of polychlorinated biphenyl (PCB) exposure in oviparous species. Research was undertaken to determine the extent of PCB accumulation in alligators (Alligator mississippiensis) at sites along the coast of South Carolina and to evaluate the utility of CAMs as surrogate tissues for determining PCB concentrations in whole alligator eggs. Polychlorinated biphenyls were found in eggs and CAMs of alligators from both sites examined. Concentrations of PCBs were higher in CAMs (p = 0.02) and eggs (p = 0.001) from sites known to contain chlorinated hydrocarbons than from more pristine sites. Total PCBs partitioned predictably (r{sup 2} > 0.59; p < 0.02) between egg and CAM tissues indicating the utility of CAMs to serve as surrogate tissues when comparing total PCB concentrations in whole eggs. Tetrachloro through octachloro biphenyl homologues and total PCBs in CAMs from reference areas were correlated with concentrations of these homologues in eggs. At contaminated sites, total PCB concentrations in CAMs were correlated with total PCB concentrations in eggs.

  10. A 2-oxoglutarate-dependent dioxygenase from Ruta graveolens L. exhibits p-coumaroyl CoA 2'-hydroxylase activity (C2'H): a missing step in the synthesis of umbelliferone in plants.

    Science.gov (United States)

    Vialart, Guilhem; Hehn, Alain; Olry, Alexandre; Ito, Kyoko; Krieger, Celia; Larbat, Romain; Paris, Cedric; Shimizu, Bun-Ichi; Sugimoto, Yukihiro; Mizutani, Masaharu; Bourgaud, Frederic

    2012-05-01

    Coumarins are important compounds that contribute to the adaptation of plants to biotic or abiotic stresses. Among coumarins, umbelliferone occupies a pivotal position in the plant phenylpropanoid network. Previous studies indicated that umbelliferone is derived from the ortho-hydroxylation of p-coumaric acid by an unknown biochemical step to yield 2,4-dihydroxycinnamic acid, which then undergoes spontaneous lactonization. Based on a recent report of a gene encoding a 2-oxoglutarate-dependent dioxygenase from Arabidopsis thaliana that exhibited feruloyl CoA 6'-hydroxylase activity (Bourgaud et al., 2006), we combined a bioinformatic approach and a cDNA library screen to identify an orthologous ORF (Genbank accession number JF799117) from Ruta graveolens L. This ORF shares 59% amino acid identity with feruloyl CoA 6'-hydroxylase, was functionally expressed in Escherichia coli, and converted feruloyl CoA into scopoletin and p-coumaroyl CoA into umbelliferone with equal activity. Its bi-functionality was further confirmed in planta: transient expression of JF799117 in Nicotiana benthamiana yielded plants with leaves containing high levels of umbelliferone and scopoletin when compared to control plants, which contained barely detectable traces of these compounds. The expression of JF799117 was also tightly correlated to the amount of umbelliferone that was found in UV-elicited R. graveolens leaves. Therefore, JF799117 encodes a p-coumaroyl CoA 2'-hydroxylase in R. graveolens, which represents a previously uncharacterized step in the synthesis of umbelliferone in plants. Psoralen, which is an important furanocoumarin in R. graveolens, was found to be a competitive inhibitor of the enzyme, and it may exert this effect through negative feedback on the enzyme at an upstream position in the pathway.

  11. Identification of PAHX, a Refsum disease gene.

    Science.gov (United States)

    Mihalik, S J; Morrell, J C; Kim, D; Sacksteder, K A; Watkins, P A; Gould, S J

    1997-10-01

    Refsum disease is an autosomal recessive disorder characterized by retinitis pigmentosa, peripheral polyneuropathy, cerebellar ataxia and increased cerebrospinal fluid protein. Biochemically, the disorder is defined by two related properties: pronounced accumulation of phytanic acid and selective loss of the peroxisomal dioxygenase required for alpha-hydroxylation of phytanoyl-CoA2. Decreased phytanic-acid oxidation is also observed in human cells lacking PEX7, the receptor for the type-2 peroxisomal targetting signal (PTS2; refs 3,4), suggesting that the enzyme defective in Refsum disease is targetted to peroxisomes by a PTS2. We initially identified the human PAHX and mouse Pahx genes as expressed sequence tags (ESTs) capable of encoding PTS2 proteins. Human PAHX is targetted to peroxisomes, requires the PTS2 receptor for peroxisomal localization, interacts with the PTS2 receptor in the yeast two-hybrid assay and has intrinsic phytanoyl-CoA alpha-hydroxylase activity that requires the dioxygenase cofactor iron and cosubstrate 2-oxoglutarate. Radiation hybrid data place PAHX on chromosome 10 between the markers D10S249 and D10S466, a region previously implicated in Refsum disease by homozygosity mapping. We find that both Refsum disease patients examined are homozygous for inactivating mutations in PAHX, demonstrating that mutations in PAHX can cause Refsum disease.

  12. Spectroscopic and computational studies of NTBC bound to the non-heme iron enzyme (4-hydroxyphenyl)pyruvate dioxygenase: active site contributions to drug inhibition.

    Science.gov (United States)

    Neidig, Michael L; Decker, Andrea; Kavana, Michael; Moran, Graham R; Solomon, Edward I

    2005-12-01

    (4-Hydroxyphenyl)pyruvate dioxygenase (HPPD) is an alpha-keto-acid-dependent dioxygenase which catalyzes the conversion of (4-hydroxyphenyl)pyruvate (HPP) to homogentisate as part of tyrosine catabolism. While several di- and tri-ketone alkaloids are known as inhibitors of HPPD and used commercially as herbicides, one such inhibitor, [2-nitro-4-(trifluoromethyl)benzoyl]-1,3-cyclohexanedione (NTBC), has also been used therapeutically to treat type I tyrosinemia and alkaptonuria in humans. To gain further insight into the mechanism of inhibition by NTBC, a combination of CD/MCD spectroscopy and DFT calculations of HPPD/Fe(II)/NTBC has been performed to evaluate the contribution of the Fe(II)-NTBC bonding interaction to the high affinity of this drug for the enzyme. The results indicate that the bonding of NTBC to Fe(II) is very similar to that for HPP, both involving similar pi-backbonding interactions between NTBC/HPP and Fe(II). Combined with the result that the calculated binding energy of NTBC is, in fact, approximately 3 kcal/mol less than that for HPP, the bidentate coordination of NTBC to Fe(II) is not solely responsible for its extremely high affinity for the enzyme. Thus, the pi-stacking interactions between the aromatic rings of NTBC and two phenyalanine residues, as observed in the crystallography of the HPPD/Fe(II)/NTBC complex, appear to be responsible for the observed high affinity of drug binding.

  13. Hydroxylation of aspartic acid in domains homologous to the epidermal growth factor precursor is catalyzed by a 2-oxoglutarate-dependent dioxygenase.

    Science.gov (United States)

    Stenflo, J; Holme, E; Lindstedt, S; Chandramouli, N; Huang, L H; Tam, J P; Merrifield, R B

    1989-01-01

    3-Hydroxyaspartic acid and 3-hydroxyasparagine are two rare amino acids that are present in domains homologous to the epidermal growth factor precursor in vitamin K-dependent plasma proteins as well as in proteins that do not require vitamin K for normal biosynthesis. They are formed by posttranslational hydroxylation of aspartic acid and asparagine, respectively. The first epidermal growth factor-like domain in factor IX (residues 45-87) was synthesized with aspartic acid in position 64, replacing 3-hydroxyaspartic acid. It was used as substrate in a hydroxylase assay with rat liver microsomes as the source of enzyme and reaction conditions that satisfy the requirements of 2-oxoglutarate-dependent dioxygenases. The synthetic peptide stimulated the 2-oxoglutarate decarboxylation in contrast to synthetic, modified epidermal growth factor (Met-21 and His-22 deleted and Glu-24 replaced by Asp) and synthetic peptides corresponding to residues 60-71 in human factor IX. This indicates that the hydroxylase is a 2-oxoglutarate-dependent dioxygenase with a selective substrate requirement. Images PMID:2492106

  14. 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.

  15. 3,4-Dihydroxyphenylacetate 2,3-dioxygenase from Pseudomonas aeruginosa: An Fe(II)-containing enzyme with fast turnover

    Science.gov (United States)

    Kamutira, Philaiwarong; Watthaisong, Pratchaya; Thotsaporn, Kittisak; Tongsook, Chanakan; Juttulapa, Maneerat; Nijvipakul, Sarayut; Chaiyen, Pimchai

    2017-01-01

    3,4-dihydroxyphenylacetate (DHPA) dioxygenase (DHPAO) from Pseudomonas aeruginosa (PaDHPAO) was overexpressed in Escherichia coli and purified to homogeneity. As the enzyme lost activity over time, a protocol to reactivate and conserve PaDHPAO activity has been developed. Addition of Fe(II), DTT and ascorbic acid or ROS scavenging enzymes (catalase or superoxide dismutase) was required to preserve enzyme stability. Metal content and activity analyses indicated that PaDHPAO uses Fe(II) as a metal cofactor. NMR analysis of the reaction product indicated that PaDHPAO catalyzes the 2,3-extradiol ring-cleavage of DHPA to form 5-carboxymethyl-2-hydroxymuconate semialdehyde (CHMS) which has a molar absorptivity of 32.23 mM-1cm-1 at 380 nm and pH 7.5. Steady-state kinetics under air-saturated conditions at 25°C and pH 7.5 showed a Km for DHPA of 58 ± 8 μM and a kcat of 64 s-1, indicating that the turnover of PaDHPAO is relatively fast compared to other DHPAOs. The pH-rate profile of the PaDHPAO reaction shows a bell-shaped plot that exhibits a maximum activity at pH 7.5 with two pKa values of 6.5 ± 0.1 and 8.9 ± 0.1. Study of the effect of temperature on PaDHPAO activity indicated that the enzyme activity increases as temperature increases up to 55°C. The Arrhenius plot of ln(k’cat) versus the reciprocal of the absolute temperature shows two correlations with a transition temperature at 35°C. Two activation energy values (Ea) above and below the transition temperature were calculated as 42 and 14 kJ/mol, respectively. The data imply that the rate determining steps of the PaDHPAO reaction at temperatures above and below 35°C may be different. Sequence similarity network analysis indicated that PaDHPAO belongs to the enzyme clusters that are largely unexplored. As PaDHPAO has a high turnover number compared to most of the enzymes previously reported, understanding its biochemical and biophysical properties should be useful for future applications in biotechnology

  16. Separation and enrichment of six indicator polychlorinated biphenyls from real waters using a novel magnetic multiwalled carbon nanotube composite absorbent.

    Science.gov (United States)

    Zhang, Jiabin; Gan, Ning; Pan, Muyun; Lin, Saichai; Cao, Yuting; Wu, Dazhen; Long, Nengbing

    2015-03-01

    A novel and effective magnetic multiwalled carbon nanotube composite for the separation and enrichment of polychlorinated biphenyls was developed. Fe3 O4 @SiO2 core-shell structured nanoparticles were first synthesized, then the poly(sodium 4-styrenesulfonate) was laid on its surface to prepare the polyanionic magnetic nanoparticles. The above materials were then grafted with polycationic multiwalled carbon nanotubes, which were modified by polydiallyl dimethyl ammonium chloride through the layer-by-layer self-assembly approach. Its performance was tested by magnetic solid-phase extraction and gas chromatography with mass spectrometry for the determination of six kinds of indicator polychlorinated biphenyls in water samples. Under optimal conditions, the spiked recoveries of several real samples for six kinds of polychlorinated biphenyls (PCB28, PCB52, PCB101, PCB138, PCB153, PCB180) were in the range of 73.4-99.5% with relative standard deviations varying from 1.5 to 8.4%. All target compounds showed good linearities in the tested range with correlation coefficients higher than 0.9993. The limits of quantification for six kinds of indicator polychlorinated biphenyls were between 0.018 and 0.039 ng/mL. The proposed method was successfully applied to analyze polychlorinated biphenyls in real water samples. Satisfactory results were obtained using the effective magnetic absorbent.

  17. Enantiomer Separation of α-Dimethyl Dicarboxylate Biphenyl and Related Biphenyl Compounds by Normal Phase HPLC on Polysaccharide Based Chiral Stationary Phases

    Institute of Scientific and Technical Information of China (English)

    LIU,Yue-Qi(刘月启); HAN,Xiao-Qian(韩小茜); Qi,Bang-Feng(齐邦峰); LIU,Chun-Hui(柳春辉); LI,Yong-Min(李永民); CHEN,Li-Ren(陈立仁)

    2002-01-01

    Cellulose tris(4-methylphenylcarbamate), amylose tris(3,5-dimethylpphenylcarbamate) and amylose tris (phenylcarbamate)were prepared by the method reported by Okamoto and were coated onto an aminopropylated mesoporous spherical silica gel. These final products were used as chiral stationary phases of high performance liquid chromatography for the eighteen structurally related biphenyl conmpounds. The resolution was made using normal-phase methodology with a mobile phase consisting of n-hexane-alcohol (ethanol, 1-propanol, 2-propanol or 1-butanol). The effects of various aliphatic alcohols in the mobile phase were studied. The structural features of the solutes that influence their k'were discussed. A dominant effect of trifluoroaetic acid on chiral separation of aacidicdic solutes was noted.

  18. [Exposure to polychlorinated biphenyls (PCBs) in food and cancer risk: recent advances].

    Science.gov (United States)

    Roveda, Anna Maria; Veronesi, Licia; Zoni, Roberta; Colucci, Maria Eugenia; Sansebastiano, Giuliano

    2006-01-01

    Polychlorinated Biphenyls are synthetic chlorinated hydrocarbon compounds whose commercial production started in the thirties and that have been widely used in the electro-technical industry. Although their production was stopped over 25 years ago, the Stockholm Convention included these compounds among the list of Persistent Organic Pollutants (POPs). In fact, humans continue to be exposed to the toxic effects of PCBs because of their resistance to chemical and biological decomposition, their capacity of bio-accumulation and their long half-life. Studies performed so far have pointed out a possible association between exposure to Polychlorinated Biphenyls and increased risk of developing some types of cancer (breast, prostate, testicular, ovarian and uterine cancers); it has also been suggested that these compounds may act as disruptive endocrine and cause infertility as well as other hormone-regulated disorders. PCBs accumulate in organisms through the food chain, and food is therefore the main exposure source for humans: it accounts for over 90% of exposure, the highest concentrations being found in fish (such as salmon and shellfish), dairy products (especially milk and butter) and animal fat. Moreover, waste-heaps, illegal disposal of oil waste and combustion of certain waste products in incineration plants represent sources of environmental pollution. The highest levels of PCBs in the environment were found in the early 1970s; since then concentrations of Polychlorinated Biphenyls have gradually decreased in all environmental components (water, air, earth and sediments), in fish, in other food products and lastly also in humans, thus suggesting that the associated risks have also likewise diminished.

  19. Weakly faceted cellular patterns versus growth-induced plastic deformation in thin-sample directional solidification of monoclinic biphenyl.

    Science.gov (United States)

    Börzsönyi, Tamás; Akamatsu, Silvère; Faivre, Gabriel

    2009-11-01

    We present an experimental study of thin-sample directional solidification (T-DS) in impure biphenyl. The platelike growth shape of the monoclinic biphenyl crystals includes two low-mobility (001) facets and four high-mobility {110} facets. Upon T-DS, biphenyl plates oriented with (001) facets parallel to the sample plane can exhibit either a strong growth-induced plastic deformation (GID), or deformation-free weakly faceted (WF) growth patterns. We determine the respective conditions of appearance of these phenomena. GID is shown to be a long-range thermal-stress effect, which disappears when the growth front has a cellular structure. An early triggering of the cellular instability allowed us to avoid GID and study the dynamics of WF patterns as a function of the orientation of the crystal.

  20. Polychlorinated biphenyl (PCB) induction of CYP3A4 enzyme activity in healthy Faroese adults

    DEFF Research Database (Denmark)

    Petersen, Maria Skaalum; Halling, Jónrit; Damkier, Per

    2007-01-01

    The CYP3A4 enzyme is, along with other cytochrome P450 enzymes, involved in the metabolism of environmental pollutants and is highly inducible by these substances. A commercial polychlorinated biphenyl (PCB) mixture, 1,1,1,-trichloro-2-(o-chlorophenyl), 2-(p'-chlorophenyl)ethane (o,p'-DDT) and 1...... analysis showed significant associations between 6beta-OHC/FC ratios and summation PCB, PCB-TEQ and p,p'-DDE, o,p'-DDT and HCB, respectively, but the associations were statistically significant for men only....

  1. trans-Tetraaquabis(nicotinamide-κNcadmium(II biphenyl-4,4′-disulfonate

    Directory of Open Access Journals (Sweden)

    Changlun Shao

    2008-02-01

    Full Text Available In the title compound, [Cd(C6H6N2O2(H2O4](C10H8O6S2, the CdII ion is located on a crystallographic inversion centre. An octahedral coordination geometry is defined by four water molecules in one plane, and two trans N-atom donors of the nicotinamide ligands. The biphenyl-4,4′-disulfonate anion also lies on a crystallographic inversion centre. In the crystal structure, the complex cations are connected to the counter-anions via N—H...O and O—H...O hydrogen bonds, forming a three-dimensional network.

  2. Electrochemical and optical properties of biphenyl bridged-dicarbazole oligomer films: Electropolymerization and electrochromism

    Energy Technology Data Exchange (ETDEWEB)

    Koyuncu, Sermet [Department of Chemistry, Faculty of Sciences and Arts, Canakkale Onsekiz Mart University, 17020 Canakkale (Turkey); Can Vocational School, Canakkale Onsekiz Mart University, 17400 Canakkale (Turkey)], E-mail: sermetkoyuncu@hotmail.com; Gultekin, Burak [Solar Energy Institute, Ege University, 35100 Bornova, Izmir (Turkey); Zafer, Ceylan [Solar Energy Institute, Ege University, 35100 Bornova, Izmir (Turkey)], E-mail: ceylan.zafer@ege.edu.tr; Bilgili, Hakan; Can, Mustafa; Demic, Serafettin [Solar Energy Institute, Ege University, 35100 Bornova, Izmir (Turkey); Kaya, Ismet [Department of Chemistry, Faculty of Sciences and Arts, Canakkale Onsekiz Mart University, 17020 Canakkale (Turkey); Icli, Siddik [Solar Energy Institute, Ege University, 35100 Bornova, Izmir (Turkey)

    2009-10-01

    4,4'-Di(N-carbazoyl)biphenyl monomer (CBP) was synthesized and coated onto ITO-glass surface by electrochemical oxidative polymerization. Its CV shows two distinct one-electron and stepwise oxidation processes occurred at 1.29 and 1.61 V. By using this property, the monomer was electrochemically polymerized separately at these oxidation states and thus, two different oligomer films were obtained afterwards. Their spectro-electrochemical and electrochromic properties were also investigated. Switching ability of the oligomers was evaluated by kinetic studies upon measuring the percent transmittance (%T) at their maximum contrast point, indicating that these oligomers were found to be suitable material for electrochromic devices.

  3. Synthesis of new biphenyl-substituted quinoline derivatives, preliminary screening and docking studies

    Indian Academy of Sciences (India)

    Nellisara D Shashikumar; Ganganaika Krishnamurthy; Halehatti S Bhojyanaik; Mayasandra R Lokesh; Kaginalli S Jithendrakumara

    2014-01-01

    New quinoline derivatives containing biphenyl ring were synthesized and characterized by IR, 1H NMR and mass spectral studies. The synthesized compounds were screened for antimicrobial, anthelmintic activities as well as free radical scavenging property against the DPPH radical. The minimum inhibition concentration values showed promising inhibiting activity and are potent biological agents. The compounds showed minimum binding energy towards -tubulin. The compounds 11a, 11c, 13c and 13d have good affinity towards the active pocket and may be considered as a good inhibitor of -tubulin.

  4. Separation of Biphenyl Nitrile Compounds by Microemulsion Electrokinetic Chromatography with Mixed Surfactants

    Institute of Scientific and Technical Information of China (English)

    Su Xuan GONG; Tao BO; Lan HUANG; Ke An LI; Hu Wei LIU

    2004-01-01

    A mixture of nine biphenyl nitrile compounds with high hydrophobicity and similar structures was successfully separated by microemulsion electrokinetic chromatography (MEEKC) within 30 min. The buffer system contained 100 mmol/L sodium dodecyl sulfate (SDS), 80 mmol/L sodium cholate (SC), 0.81% heptane, 7.5% n-butanol, 10% acetonitrile and 10 mmol/L borate. The addition of SC, organic modifiers, sample preparation and temperature all showed remarkable effect on the separation. Meanwhile, the MEEKC method was briefly compared with micellar electrokinetic chromatography (MEKC) method.

  5. Library of biphenyl privileged substructures using a safety-catch linker approach

    DEFF Research Database (Denmark)

    Severinsen, Rune; Bourne, Gregory T; Tran, Tran T

    2008-01-01

    A biphenyl privileged structure library containing three attachment points were synthesized using a catechol-based safety-catch linker strategy. The method requires the attachment of a bromo-acid to the linker, followed by a Pd-catalyzed Suzuki cross-coupling reaction. Further derivatization......, activation of the linker with strong acid and aminolysis afforded the respective products in high purity and good overall yield. To show the versatility of the synthesis, a 199-member library was generated. The library samples both conformational and chemical diversity about a well-known privileged...

  6. Development and characterization of new polyclonal antibodies specific for three polychlorinated biphenyls

    Institute of Scientific and Technical Information of China (English)

    Han Yu Chen; Hui Sheng Zhuang; Chun Zhou

    2009-01-01

    Three polychlorinated biphenyls(PCBs)congeners and their corresponding haptens bearing four carbon length carboxylic groups that can be linked to a protein for raising antibodies were synthesized.The three resultant immunogens were fabricated and used to stimulate immune responses in rabbits to survey the characteristics of the haptens.Three of the resultant polyclonal antibodies(Pabs)were obtained.The antiserum exhibited relatively high antibody titres(1:32-64)in double agar diffusion.◎2008 Hui Sheng Zhuang.Published by Elsevier B.V.on behalf of Chinese Chemical Society.All rights reserved.

  7. 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)

    Bjoern, 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...

  8. 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.

  9. 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.

  10. Enhanced iodide sequestration by 3-biphenyl-5,6-dihydroimidazo 2,1-b thiazole in sodium/iodide sym-porter (NIS)-expressing cells

    Energy Technology Data Exchange (ETDEWEB)

    Lecat-Guillet, N.; Ambroise, Y. [CEA, DSV, Dept Bioorgan Chem andt IsotopLabelling, Inst Biol and Technol, iBiTecS, F-91191 Gif Sur Yvette (France)

    2008-07-01

    The ability of the sodium/iodide sym-porter (NIS) to take up iodide has long provided the basis for cyto-reductive gene therapy and cancer treatment with radio-iodide. One of the major limitations of this approach is that radio-iodide retention in NIS-expressing cells is not sufficient for their destruction. We identified and characterized a small organic molecule capable of increasing iodide retention in HEK293 cells permanently transfected with human NIS cDNA (hNIS-HEK293) and in the rat thyroid-derived cell line FRTL-5. In the presence of 3-biphenyl-4'-yl-5,6-dihydroimidazo[2,1-b)thiazole (ISA1), the transmembrane iodide concentration gradient was increased up to 4.5-fold. Our experiments indicate that the imidazo-thiazole derivative acts either by inhibiting anion efflux mechanisms, or by promoting the relocation of iodide into subcellular compartments. This new compound is not only an attractive chemical tool to investigate the mechanisms of iodide flux at the cellular level, but also opens promising perspectives in the treatment of cancer after NIS gene transfer. (authors)

  11. Biomonitoring of non-dioxin-like polychlorinated biphenyls in transgenic Arabidopsis using the mammalian pregnane X receptor system: a role of pectin in pollutant uptake.

    Directory of Open Access Journals (Sweden)

    Lieming Bao

    Full Text Available Polychlorinated biphenyls (PCBs are persistent organic pollutants damaging to human health and the environment. Techniques to indicate PCB contamination in planta are of great interest to phytoremediation. Monitoring of dioxin-like PCBs in transgenic plants carrying the mammalian aryl hydrocarbon receptor (AHR has been reported previously. Herein, we report the biomonitoring of non-dioxin-like PCBs (NDL-PCBs using the mammalian pregnane X receptor (PXR. In the transgenic Arabidopsis designated NDL-PCB Reporter, the EGFP-GUS reporter gene was driven by a promoter containing 18 repeats of the xenobiotic response elements, while PXR and its binding partner retinoid X receptor (RXR were coexpressed. Results showed that, in live cells, the expression of reporter gene was insensitive to endogenous lignans, carotenoids and flavonoids, but responded to all tested NDL-PCBs in a dose- and time- dependent manner. Two types of putative PCB metabolites, hydroxy- PCBs and methoxy- PCBs, displayed different activation properties. The vascular tissues seemed unable to transport NDL-PCBs, whereas mutation in QUASIMODO1 encoding a 1,4-galacturonosyltransferase led to reduced PCB accumulation in Arabidopsis, revealing a role for pectin in the control of PCB translocation. Taken together, the reporter system may serve as a useful tool to biomonitor the uptake and metabolism of NDL-PCBs in plants.

  12. Ab initio study of long-range electron transfer between biphenyl anion radical and naphthalene

    Institute of Scientific and Technical Information of China (English)

    李象远; 肖顺清; 何福城

    1999-01-01

    After the separation of the donor, the aeceptor, and the σ-type bridge from the π-σ-π system, the geometries of biphenyl, biphenyl anion radical, naphthalene, and naphthalene anion radical are optimized, and then the reorganization energy for the intermolecular electron transfer (ET) at the levels of HF/4-31G and HF/DZP is calculated. The ET matrix elements of the self-exchange reactions of the π-σ-π systems have been calculated by means of both the direct calculation based on the variational principle, and the transition energy between the molecular orbitals at the linear coordinate R=0.5. For the cross reactions, the ET matrix element and the geometry of the transition state are determined by searching the minimum energy splitting △min along the reaction coordinate. In the evaluation of the solvent reorganization energy of the ET in solution, the Marcus’ two-sphere model has been invoked. A few of ET rate constants for the intramolecular ET reactions for the π-σ-π systems, which contain

  13. Tissue damage after acute intoxication by polychlorinated biphenyls (PCBs in cockroaches Blattella germanica

    Directory of Open Access Journals (Sweden)

    S Lambiase

    2009-06-01

    Full Text Available It is common knowledge that polychlorinated biphenyls (PCBs represent a serious threat to the health of both vertebrates and invertebrates. As far as the former are concerned, especially as regards human beings, a broad literature describes the direct and indirect effects induced by the PCBs on their systems and organs. Among invertebrates, the information available is mostly related to arthropods and is, however, very scarce. The aim of this work was to evaluate the effects of polychlorinated biphenyls (PCBs on tissues and organs of individuals belonging to a species of Blattaria (Blattella germanica treated with various doses of this toxic material. The pathologies found became more serious as the dosage increased and were present throughout the entire digestive system, in the fat body and in the male gonads: in these areas cell and tissue breakdown and severely damaged spermiogenesis were observed. In particular, the testicles, Malpighian tubules and fat body accumulated an amorphous basophilic PAS-positive substance. Furthermore, the NOS-dependent NADPH diaphorase activity pattern in the retina and optic lobes was more evident in the treated than in the control insects.

  14. Occurrence and congeners specific of polychlorinated biphenyls in agricultural soils from Southern Jiangsu, China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jian-ying; QIU Li-min; HE Jia; LIAO Yuan; LUO Yong-ming

    2007-01-01

    A total of 198 agricultural soil samples were collected from Zhangjiagang and Changshu in Southern Jiangsu for analysis of 13 polychlorinated biphenyls(PCBs)in order to assess the levels of pollution,sources,area distribution,and potential risk for the environment.All methods were rigorously tested and an adequate quality control was ensured.Only one site had no PCBs residues,and the highest total PCBs concentration in the surface soils was 32.83 ng/g.The average concentration in all the soil samples was 4.13ng/g.signaling low-level pollution.Tetra-,penta-,and hexa-chlorinated biphenyls were dominant speoes in soil samples,accounnng for more than 75%of ΣPCBs in the soil samples.PCB118 was the most abundant congener in all the samples.The PCB118 Was about 20%of ΣPCBs.The soil organic matter content showed only a weak correlation with the levels of all PCB congeners,in which a better correlation was noted for the more volatile lighter PCB congeners than for the heavier homologues.To a certain extent,the sources and land use seemed to influence the levels of PCBs.

  15. Hydroxy and methylsulfone metabolites of polychlorinated biphenyls in the human blood and tissues

    Energy Technology Data Exchange (ETDEWEB)

    Masuda, Yoshito; Haraguchi, Koichi [Daiichi College of Pharmaceutical Sciences, Fukuoka (Japan)

    2004-09-15

    Polychlorinated biphenyls (PCBs) are a group of chlorinated compounds which have polluted the global environment, persistently retained in wildlife and humans, and eventually affected the human health. PCBs are biotransformed to mainly hydroxy (HO-) and methylsulfone (MeSO{sub 2}-) metabolites in the animal and human tissues. About ten thousands of chemical and biological researches on PCBs, HOPCBs and MeSO{sub 2}-PCBs have been reported and reviewed so far. Letcher et al. cleverly reviewed the HO-PCBs and MeSO2-PCBs in 2000. We review the contamination of HO-PCBs and MeSO{sub 2}-PCBs in human tissues and their possible effects to human health. Different positional numberings of Cl-, HO- and MeSO{sub 2}- on biphenyl rings were used by different authors. Then, nomenclature of PCB metabolite was assessed by Maervoet et al. and they suggested to use the IUPAC chemical name and number of parent PCB congener with the subsequent assignment of the phenyl ring position number of the HO- or MeSO{sub 2}- substituent number afterward.

  16. Net trophic transfer efficiencies of polychlorinated biphenyl congeners to lake trout (Salvelinus namaycush) from its prey

    Science.gov (United States)

    Madenjian, Charles P.; David, Solomon R.; Rediske, Richard R.; O’Keefe, James P.

    2012-01-01

    Lake trout (Salvelinus namaycush) were fed bloater (Coregonus hoyi) in eight laboratory tanks over a 135-d experiment. At the start of the experiment, four to nine fish in each tank were sacrificed, and the concentrations of 75 polychlorinated biphenyl (PCB) congeners within these fish were determined. Polychlorinated biphenyl congener concentrations were also determined in the 10 lake trout remaining in each of the eight tanks at the end of the experiment as well as in the bloater fed to the lake trout. Each lake trout was weighed at the start and the end of the experiment, and the amount of food eaten by the lake trout was recorded. Using these measurements, net trophic transfer efficiency (γ) from the bloater to the lake trout in each of the eight tanks was calculated for each of the 75 congeners. Results showed that γ did not vary significantly with the degree of chlorination of the PCB congeners, and γ averaged 0.66 across all congeners. However,γ did show a slight, but significant, decrease as logKOW increased from 6.0 to 8.2. Activity level of the lake trout did not have a significant effect on γ.

  17. Net trophic transfer efficiencies of polychlorinated biphenyl congeners to lake whitefish (Coregonus clupeaformis) from their food

    Science.gov (United States)

    Madenjian, C.P.; O'Connor, D.V.; Rediske, R.R.; O'Keefe, J. P.; Pothoven, S.A.

    2008-01-01

    Lake whitefish (Coregonus clupeaformis) were fed rainbow smelt (Osmerus mordax) in four laboratory tanks over a 133-d experiment. At the start of the experiment, 10 to 14 of the fish in each tank were sacrificed, and the concentrations of 40 polychlorinated biphenyl (PCB) congeners within these fish were determined. Polychlorinated biphenyl congener concentrations were also determined in the 15 lake whitefish remaining in each of the four tanks at the end of the experiment as well as in the rainbow smelt fed to the lake whitefish. Each lake whitefish was weighed at the start and the end of the experiment, and the amount of food eaten by the lake whitefish during the experiment was tracked. Using these measurements, net trophic transfer efficiency (??) from the rainbow smelt to the lake whitefish in each of the four tanks was calculated for each of the 40 PCB congeners. Results showed that ?? decreased exponentially as log KOW for the congeners increased from 6 to 8. Further, ?? averaged 0.70 for the tetrachloro congeners but averaged only 0.45 for the higher chlorinated congeners. ?? 2008 SETAC.

  18. The associations between the environmental exposure to polychlorinated biphenyls (PCBs) and breast cancer risk and progression

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Polychlorinated biphenyls(PCBs) are chlorinated biphenyl compounds with wide applications in the industry.In spite of a ban on their production in the late 1970s,PCBs,as a group of POPs,are still persistent and widely spread in the environment,posing potential threats to human health.The role of PCBs as etiologic agents for breast cancer has been intensively explored in a variety of in vivo,animal and epidemiologic studies.Initial investigations indicated higher levels of PCBs in mammary tissues or sera corresponded to the occurrence of breast cancer,but later studies showed no positive association between PCB exposure and breast cancer development.More recent data suggested that the CYP1A1 m2 polymorphisms might add increased risk to the etiology of breast cancer in women with environmental exposure to PCBs.PCBs are implicated in advancing breast cancer progression,and our unpublished data reveals that PCBs activate the ROCK signaling to enhance breast cancer metastasis.Therefore,the correlation between PCB exposure and breast cancer risk warrants further careful investigations.

  19. Acireductone dioxygenase- (ARD-) type reactivity of a nickel(II) complex having monoanionic coordination of a model substrate: product identification and comparisons to unreactive analogues.

    Science.gov (United States)

    Szajna-Fuller, Ewa; Rudzka, Katarzyna; Arif, Atta M; Berreau, Lisa M

    2007-07-09

    A mononuclear Ni(II) complex ([(6-Ph2TPA)Ni(PhC(O)C(OH)C(O)Ph)]ClO4 (1)), supported by the 6-Ph2TPA chelate ligand (6-Ph2TPA = N,N-bis((6-phenyl-2-pyridyl)methyl)-N-((2-pyridyl)methyl)amine) and containing a cis-beta-keto-enolate ligand having a C2 hydroxyl substituent, undergoes reaction with O2 to produce a Ni(II) monobenzoate complex ([(6-Ph2TPA)Ni(O2CPh)]ClO4 (3)), CO, benzil (PhC(O)C(O)Ph), benzoic acid, and other minor unidentified phenyl-containing products. Complex 3 has been identified through independent synthesis and was characterized by X-ray crystallography, 1H NMR, FAB-MS, FTIR, and elemental analysis. A series of cis-beta-keto-enolate Ni(II) complexes supported by the 6-Ph2TPA ligand ([(6-Ph2TPA)Ni(PhC(O)CHC(O)Ph)]ClO4 (4), [(6-Ph2TPA)Ni(CH3C(O)CHC(O)CH3)]ClO4 (5), and [(6-Ph2TPA)Ni(PhC(O)CHC(O)C(O)Ph) (6)) have been prepared and characterized. While these complexes exhibit structural and/or spectroscopic similarity to 1, all are unreactive with O2. The results of this study are discussed in terms of relevance to Ni(II)-containing acireductone dioxygenase enzymes, as well as in the context of recently reported cofactor-free, quercetin, and beta-diketone dioxygenases.

  20. Purification and some properties of component B of the 4-chlorophenylacetate 3,4-dioxygenase from Pseudomonas species strain CBS 3.

    Science.gov (United States)

    Schweizer, D; Markus, A; Seez, M; Ruf, H H; Lingens, F

    1987-07-05

    4-Chlorophenylacetate 3,4-dioxygenase system from Pseudomonas sp. CBS 3 consists of two protein components, a red-brown iron-sulfur protein (component A) which functions as dioxygenase and an orange-colored reductase (component B). Component B was purified by a five-step procedure. Criterion of purity was sodium dodecyl sulfate-polyacrylamide gel electrophoresis, which also showed that the protein consists of one polypeptide species with a molecular weight of 35,000. With gel chromatography on Sephadex G-100 also, a molecular weight of 35,000 was found for the native enzyme, suggesting a monomeric structure for the reductase enzyme. The isoelectric point was determined as pH 4.8. The visible absorption spectrum of the homogeneous protein exhibits maxima at 336, 394, and 458 nm. One mol of FMN, 2.1 mol of iron, and 1.7 mol of acid-labile sulfide were found in one mol of component B. The EPR-spectrum of the reduced form of the enzyme (with NADH) showed two types of signals. The signal at g values of 2.03, 1.94, and 1.90 was assigned to an iron-sulfur cluster of the [2Fe-2S]-type. The properties of the other signal type at g = 2.004 are characteristic of flavosemiquinone radical which does not show coupling to an other paramagnetic center. The apparent Km values for 2,6-dichlorophenolindophenol, cytochrome c, and NADH were calculated from Lineweaver-Burk plots as 6.3, 2.3, and 32 microM, respectively. Inhibitors of the reductase are metal-chelating reagents and sulfhydryl-inhibiting compounds. Component B reduces several redox compounds: 2,6-dichlorophenolindophenol, potassium hexacyanoferrat III, cytochrome c, methylene blue, and nitro blue tetrazolium.

  1. Mechanism of repair of acrolein- and malondialdehyde-derived exocyclic guanine adducts by the α-ketoglutarate/Fe(II) dioxygenase AlkB.

    Science.gov (United States)

    Singh, Vipender; Fedeles, Bogdan I; Li, Deyu; Delaney, James C; Kozekov, Ivan D; Kozekova, Albena; Marnett, Lawrence J; Rizzo, Carmelo J; Essigmann, John M

    2014-09-15

    The structurally related exocyclic guanine adducts α-hydroxypropano-dG (α-OH-PdG), γ-hydroxypropano-dG (γ-OH-PdG), and M1dG are formed when DNA is exposed to the reactive aldehydes acrolein and malondialdehyde (MDA). These lesions are believed to form the basis for the observed cytotoxicity and mutagenicity of acrolein and MDA. In an effort to understand the enzymatic pathways and chemical mechanisms that are involved in the repair of acrolein- and MDA-induced DNA damage, we investigated the ability of the DNA repair enzyme AlkB, an α-ketoglutarate/Fe(II) dependent dioxygenase, to process α-OH-PdG, γ-OH-PdG, and M1dG in both single- and double-stranded DNA contexts. By monitoring the repair reactions using quadrupole time-of-flight (Q-TOF) mass spectrometry, it was established that AlkB can oxidatively dealkylate γ-OH-PdG most efficiently, followed by M1dG and α-OH-PdG. The AlkB repair mechanism involved multiple intermediates and complex, overlapping repair pathways. For example, the three exocyclic guanine adducts were shown to be in equilibrium with open-ring aldehydic forms, which were trapped using (pentafluorobenzyl)hydroxylamine (PFBHA) or NaBH4. AlkB repaired the trapped open-ring form of γ-OH-PdG but not the trapped open-ring of α-OH-PdG. Taken together, this study provides a detailed mechanism by which three-carbon bridge exocyclic guanine adducts can be processed by AlkB and suggests an important role for the AlkB family of dioxygenases in protecting against the deleterious biological consequences of acrolein and MDA.

  2. 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.

  3. Levels of Polychlorinated Dibenzo-p-Dibenzofurans, and Biphenyls in Southern Mississippi Catfish and Estimation of Potential.

    Science.gov (United States)

    Fish consumption has been classified as one of the primary pathways of exposure to polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs) and biphenyls (PCBs). In this study, we evaluated tissue levels of the 17 laterally-substituted PCDD/Fs, 12 dioxin-like PCBs, and 97 non-...

  4. Serum concentrations of polybrominated diphenyl ethers (PBDEs) and a polybrominated biphenyl (PBB) in men from Greenland, Poland and Ukraine

    DEFF Research Database (Denmark)

    Lenters, Virissa; Thomsen, Cathrine; Smit, Lidwien A M;

    2013-01-01

    in Inuit men from across Greenland, and in men from Warsaw, Poland and Kharkiv, Ukraine. Serum was sampled between 2002 and 2004 from men 19 to 50years of age. 299 samples were analyzed for BDE-28, 47, 99, 100, 153, 154 and 183 and the brominated biphenyl BB-153 using gas chromatography-high resolution...

  5. Photochemistry treatment of polychlorinated biphenyls (PCB) in dielectric fluid; Tratamiento fotoquimico de bifenilos policlorados en fluidos dielectricos

    Energy Technology Data Exchange (ETDEWEB)

    Manzano Quinones, M. A. [Escuela Politecnica Superior de Algeciras (Spain)

    2000-07-01

    In this work a study of polychlorinated biphenyls (PCB) photodegradation in dielectric fluid have been done. The experiments has been carried out in a pilot scale photo rector with an ultraviolet light source. The results obtained showed a 92% elimination of PCB following a first kinetic order. In addition the photo reaction products have been identified. (Author) 6 refs.

  6. Impact of polychlorinated biphenyl and polycyclic aromatic hydrocarbon sequestration in sediment on bioaccumulation in aquatic food webs

    NARCIS (Netherlands)

    Moermond, C.T.A.; Roessink, I.; Jonker, M.T.O.; Meijer, T.; Koelmans, A.A.

    2007-01-01

    It is not clear whether sequestration or aging of organic chemicals like polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) limits accumulation in higher levels of aquatic food chains. Therefore, the effect of aging on accumulation was studied in 1-m3 model ecosystems that

  7. First worldwide UNEP interlaboratory study on persistent organic pollutants (POPs) with data on polychlorinated biphenyls and organochlorine pesticides

    NARCIS (Netherlands)

    Leeuwen, van S.P.J.; Bavel, van B.; Boer, de J.

    2013-01-01

    The first worldwide interlaboratory study on persistent organic pollutants (POPs) under the Stockholm Convention was organized, with a participation of 103 laboratories from Asia, Europe, the Americas, Africa and Australia, of which the majority submitted data on polychlorinated biphenyls (PCBs) and

  8. Alkoxyresorufin-O-deethylase activities and polychlorinated biphenyl patterns in shrews as biomarkers in environmental risk assessments: sensitivity and specificity

    NARCIS (Netherlands)

    Brink, van den N.W.; Bosveld, A.T.C.

    2005-01-01

    Alkoxyresorufin-O-deethylase (AROD) biomarkers are useful indicators of the exposure of organisms to dioxin-like compounds. In the current study, an in vivo validation of the use of such biomarkers in shrews was conducted. Furthermore, the use of changes in polychlorinated biphenyl (PCB) patterns as

  9. Kinetics and conductivity parameters of uptake and transport of polychlorinated biphenyls in the Caco-2 intestinal cell line model

    NARCIS (Netherlands)

    Dulfer, W.J.; Govers, H.A.J.; Groten, J.P.

    1998-01-01

    Most of the accumulation of polychlorinated biphenyls (PCBs) over the food chain can be attributed to contaminant uptake from food. The effect of fatty acid absorption on net uptake and transport fluxes of a selection of 14 PCBs over the organismal gut epithelium has been determined in monolayers of

  10. Diffusion Coefficients of Polychlorinated Biphenyls and Polycyclic Aromatic Hydrocarbons in Polydimethylsiloxane and Low-Density Polylethylene Polymers

    NARCIS (Netherlands)

    Rusina, T.; Smedes, F.; Klanova, J.

    2010-01-01

    Diffusion coefficients (D) of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) were determined by film-stacking technique in low-density polyethylene (LDPE) and two types of polydimethylsiloxane (PDMS) (also known as silicone rubber, SR) with the trade names AlteSil (TM)

  11. Plasma polychlorinated biphenyl levels in Dutch preschool children either breast-fed or formula-fed during infancy

    NARCIS (Netherlands)

    Patandin, S; WeisglasKuperus, N; deRidder, MAJ; KoopmanEsseboom, C; vanStaveren, WA; vanderPaauw, CG; Sauer, PJJ

    1997-01-01

    Objectives. This study examined the influence of lactational and in utero exposure to polychlorinated biphenyls (PCBs) on plasma PCB levels in children. Methods. Plasma PCB levels were measured in 173 children at 3.5 years, of whom 91 were breast-fed and 82 were formula-fed in infancy. Results. Medi

  12. Determination of in vitro relative potency (REP) values for mono-ortho polychlorinated biphenyls after purification with active charcoal

    NARCIS (Netherlands)

    Peters, A.K.; Leonards, P.E.G.; Zhao, B.; Bergman, A.; Denison, M.S.; Berg, van den M.

    2006-01-01

    The TEF system for dioxin-like compounds has included assignment of TEF values for mono-ortho polychlorinated biphenyls (MO-PCBs). Small traces of aryl hydrocarbon receptor (AhR)-active impurities could result in artifactually higher relative potency (REP) values. MO-PCBs -105, -118, -156, and -167

  13. Reproductive hormone profile and pubertal development in 14-year-old boys prenatally exposed to polychlorinated biphenyls

    DEFF Research Database (Denmark)

    Grandjean, Philippe; Grønlund, Ciea; Kjær, Ina M;

    2012-01-01

    Because polychlorinated biphenyls (PCBs) are thought to cause endocrine disruption, we examined 438 adolescent boys from a birth cohort in the Faroe Islands, where PCB exposures are elevated. We measured PCBs and p,p'-dichlorodiphenyldichloroethylene (DDE) in cord blood and in serum from clinical...

  14. Polychlorinated biphenyls (PCBs) in indoor air originating from sealants in contaminated and uncontaminated apartments within the same housing estate

    DEFF Research Database (Denmark)

    Frederiksen, Marie; Meyer, Harald William; Ebbehøj, Niels Erik;

    2012-01-01

    Twenty-four congeners of polychlorinated biphenyls (PCBs) were measured in 83 air samples and 20 elastic sealants samples of apartments with PCB-containing sealants. In addition, PCBs were measured in 21 air samples from reference apartments located in an uncontaminated section of the same estate...

  15. Prenatal Exposure to Polychlorinated Biphenyls and Their Hydroxylated Metabolites is Associated with Neurological Functioning in 3-Month-Old Infants

    NARCIS (Netherlands)

    Berghuis, Sietske A.; Soechitram, Shalini D.; Sauer, Pieter J. J.; Bos, Arend F.

    2014-01-01

    Polychlorinated biphenyls (PCBs) are environmental chemicals which are potentially toxic to the developing brain. Their hydroxylated metabolites (OH-PCBs) are suggested to be even more toxic. Knowledge about the health effects of prenatal OH-PCB exposure is limited. We aimed to determine whether pre

  16. 77 FR 12836 - Draft Toxicological Review of Biphenyl: In Support of Summary Information on the Integrated Risk...

    Science.gov (United States)

    2012-03-02

    ... be used to support the first two steps (hazard identification and dose-response evaluation) of the... management decisions designed to protect public health. Dated: February 23, 2012. Darrell A. Winner, Acting... AGENCY Draft Toxicological Review of Biphenyl: In Support of Summary Information on the Integrated...

  17. Polychlorinated biphenyls, glycaemia and diabetes in a population living in a highly polychlorinated biphenyls-polluted area in northern Italy: a cross-sectional and cohort study

    Directory of Open Access Journals (Sweden)

    Claudia Zani

    2013-05-01

    Full Text Available Background. Polychlorinated biphenyls (PCBs have been found to be associated with diabetes in some, but not all, studies performed so far. The aim of this study was to assess the association between PCB serum levels and glycaemia and diabetes in people living in Brescia, a highly industrialised PCB-polluted town in Northern Italy. Design and Methods. 527 subjects were enrolled in a cross-sectional population-based study: they were interviewed face-to-face in 2003 and also provided a blood sample under fasting conditions. The concentration of 24 PCB congeners was determined using gas-chromatography (GC/MS. Subsequently, all subjects were included in a follow-up (cohort study. According to the Local Health Authority health-care database, subjects were considered to be diabetic if they had diabetes at interview time (prevalent cases or during a 7-year follow-up (incident cases. Results. A total of 53 subjects (10.0% were diabetics: 28 had dia- betes at enrolment and other 25 developed the disease subsequently. Diabetes frequency increased according to the serum concentrations of total PCBs and single PCB congeners, but no association was found when estimates were adjusted for education, body mass index, age and gender by logistic regression analysis. Accordingly, glycaemia increased with PCB serum levels, but no association was observed when multiple regression analysis, including confounding factors, was performed. Conclusions. This study does not support the hypothesis that PCB environmental exposure is strictly associated with diabetes or glycaemia.

  18. Abundance and diversity of functional genes involved in the degradation of aromatic hydrocarbons in Antarctic soils and sediments around Syowa Station.

    Science.gov (United States)

    Muangchinda, C; Chavanich, S; Viyakarn, V; Watanabe, K; Imura, S; Vangnai, A S; Pinyakong, O

    2015-03-01

    Hydrocarbon catabolic genes were investigated in soils and sediments in nine different locations around Syowa Station, Antarctica, using conventional PCR, real-time PCR, cloning, and sequencing analysis. Polycyclic aromatic hydrocarbon ring-hydroxylating dioxygenase (PAH-RHD)-coding genes from both Gram-positive and Gram-negative bacteria were observed. Clone libraries of Gram-positive RHD genes were related to (i) nidA3 of Mycobacterium sp. py146, (ii) pdoA of Terrabacter sp. HH4, (iii) nidA of Diaphorobacter sp. KOTLB, and (iv) pdoA2 of Mycobacterium sp. CH-2, with 95-99% similarity. Clone libraries of Gram-negative RHD genes were related to the following: (i) naphthalene dioxygenase of Burkholderia glathei, (ii) phnAc of Burkholderia sartisoli, and (iii) RHD alpha subunit of uncultured bacterium, with 41-46% similarity. Interestingly, the diversity of the Gram-positive RHD genes found around this area was higher than those of the Gram-negative RHD genes. Real-time PCR showed different abundance of dioxygenase genes between locations. Moreover, the PCR-denaturing gradient gel electrophoresis (DGGE) profile demonstrated diverse bacterial populations, according to their location. Forty dominant fragments in the DGGE profiles were excised and sequenced. All of the sequences belonged to ten bacterial phyla: Proteobacteria, Actinobacteria, Verrucomicrobia, Bacteroidetes, Firmicutes, Chloroflexi, Gemmatimonadetes, Cyanobacteria, Chlorobium, and Acidobacteria. In addition, the bacterial genus Sphingomonas, which has been suggested to be one of the major PAH degraders in the environment, was observed in some locations. The results demonstrated that indigenous bacteria have the potential ability to degrade PAHs and provided information to support the conclusion that bioremediation processes can occur in the Antarctic soils and sediments studied here.

  19. Synthesis and Characterization of a Novel Copoly(aryl ether ketone) Containing 4, 4'-Biphenyl-bis[4-phthalazin-1(2H)-one] Moiety

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A new monomer of 4, 4'-biphenyl-bis[4-phthalazin-1(2H)-one] was synthesized from biphenyl and phthalic anhydride, and a novel copoly(aryl ether ketone) (PPEK) was synthesized from 2, 2-bis(4-hydroxyphenyl)-propane (BPA), 4, 4'-biphenyl-bis-[4-phthalazin-1(2H)-one], 4, 4'- difluorodiphenylketone (DFK). The monomer and copolymer were characterized by FT-IR and 1H-NMR. DSC and TGA were used to the novel polymer.

  20. Studies on the Quantitative Structure-activity Relationship of Substituted Biphenyls by Density Function Theory (DFT)

    Institute of Scientific and Technical Information of China (English)

    HAN Xiang-Yun; ZHENG Qing

    2007-01-01

    Geometrical configurations of 16 substituted biphenyls were computed at the B3LYP/6-311G** level with Gaussian 98 program. Based on linear solvation energy theory, lgKow as well as the structural and thermodynamic parameters obtained at this level was taken as theoretical descriptors, and corresponding equation predicting the toxicity of Daphnia magna (-lgEC50)was thus obtained, in which three parameters were contained, i.e., n-octanol/water partition coefficients (lgKow), dipole moment of the molecules (μ) and entropy (S°). For this equation, R2 =0.9582, q2 = 0.8921 and SD = 0.102. The absolute t-scores of three variables are larger than the standard one in the confidence range of 95%, which confirms the creditability and stability of this model.

  1. Problems with the polychlorinated biphenyls (PCB) in Mexico; Problematica de los bifenilos policlorados (BPC) en Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Valle, Esteban; Cruz, Maria Guadalupe [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1997-12-31

    A general overview is presented of the problems with the polychlorinated biphenyls (PCB) (askarels) in Mexico, which are mainly associated with the use of these substances in electric equipment; also, a profile of the causes why the PCBs have been classified as environmental toxic substances and a potential hazard for the health of human beings. [Espanol] Se presenta un panorama general de la problematica de bifenilos policlorados (BPC) (askareles) en Mexico, la cual esta asociada principalmente con el uso de estos compuestos en equipos electricos; asimismo, se describe una semblanza de las causas por las cuales se han catalogado a los BPC como sustancias toxicas ambientales y un peligro potencial para la salud de los seres humanos.

  2. Accumulation and depletion of polychlorinated biphenyl (PCB) congeners in the housefly (musca domestica, L. )

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, L.G. (Univ. of Illinois, Urbana (United States)); Storr-Hansen, E. (National Environmental Research Inst., Soeborg (Denmark))

    1992-01-01

    Polychlorinated biphenyl (PCB) residues in food chains and in the environment are dynamic complex mixtures and there is considerable interest in the disposition as well as toxicities of individual congeners. The persistence and biological activities of PCBs are intimately associated with microsomal monooxygenases. The house fly, Musca domestica (L.), has long been a standard organism for studies of pesticide toxicology and has an active and well-defined microsomal monooxygenase system. These oxidases in the fly can be induced by PCBs. It was considered of interest to provide data which may indicate whether or not the relatively large and mobile biomass of insects in general may play a role in the global disposition of PCBs. It was also of interest to determine if the house fly could serve as a model for determining the relative accumulation, elimination, and toxicities of individual PCB congeners.

  3. Polychlorinated biphenyls in fresh and canned fish from the Central Adriatic.

    Science.gov (United States)

    Kipcić, D; Vukusić, J

    1991-01-01

    By using the GLC method, levels of polychlorinated biphenyls (PCBs) were determined in fresh and canned fish during the 1984-88 period. Forty-six samples of fish caught in the Central Adriatic's littoral, 11 of which in a control, non-industrialized area, and 35 in an urbanized area strongly affected by industry, were collected. Also, 101 samples of canned fish were tested for PCBs. The average PCB values were 0.059 mg kg-1 and 0.287 mg kg-1 in control and polluted areas, respectively; the mean value in canned fish was 0.194 mg kg-1. Although the levels of PCBs in control and industrialized areas were found to differ, the difference was not significant statistically.

  4. Evaluating daily exposure to polychlorinated biphenyls and polybrominated diphenyl ethers in fish oil supplements.

    Science.gov (United States)

    Ashley, J T F; Ward, J S; Schafer, M W; Stapleton, H M; Velinsky, D J

    2010-08-01

    Fish oil supplements have become a popular means of increasing one's dietary intake of essential polyunsaturated fatty acids. However, there is growing concern that the levels and potential health effects of lipophilic organic contaminants such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) may diminish some of the health benefits associated with the daily consumption of fish oil supplements. In this study, ten over-the-counter fish oil supplements available in the United States were analysed for PCBs and PBDEs and daily exposures calculated. Based on manufacturers' recommended dosages, daily intakes of PCBs and PBDEs ranged from 5 to 686 ng day(-1) and from 1 to 13 ng day(-1), respectively. Daily consumption of fish oil supplements expose consumers to PCBs and PBDEs. However, in comparison with fish ingestion, fish supplements may decrease daily PCB exposure and provide a safer pathway for individuals seeking to maintain daily recommended levels of polyunsaturated fatty acids.

  5. Exposure to 27 polychlorinated biphenyls in the indoor environment of a workplace

    DEFF Research Database (Denmark)

    Pedersen, Ellen Bøtker; Ebbehøj, N E; Göen, T

    2016-01-01

    PURPOSE: To assess the exposure to a broad-spectrum of polychlorinated biphenyl congeners (PCBs) from the indoor environment through bio-monitoring of people working in a building with PCB-containing materials and elevated PCB levels in the indoor air. METHODS: A cross-sectional study comparing...... the plasma concentration of 27 PCB congeners in 15 people working in a PCB-contaminated building and 30 matched controls. RESULTS: Median concentration of eight low-chlorinated PCB congeners was significantly higher in the exposed than in the control group. The sum of median concentrations of tri + tetra......-chlorinated PCB was almost ten times higher in the exposed group than in the unexposed, and sums of dioxin-like and non-dioxin-like PCB were both relatively increased by 60 % in the exposed group. CONCLUSIONS: The occupational indoor environment may significantly add to PCB exposure, especially to the lower...

  6. Preparation and characterization of gold nanoparticles capped by peptide-biphenyl hybrids.

    Science.gov (United States)

    Pérez, Yolanda; Mann, Enrique; Herradón, Bernardo

    2011-07-15

    Gold nanoparticles were prepared using peptide-biphenyl hybrids (PBHs) as capping agents. AuNPs were characterized by different techniques including UV-Vis, TEM, EDX, FT-IR, elemental analysis, (1)H NMR and (13)C CP/MAS NMR spectroscopy. TEM analysis showed that AuNPs present diameters in the range of 1.8-3.7 nm, depending on the structure and the amount of the capping PBH used. FT-IR spectroscopy and solid-state (13)C NMR revealed that the carboxylic group of PBHs, especially in the case of the acid ligands, interacts with the gold surface (in the form of carboxylate). The results confirm that PBHs are excellent stabilizers of AuNPs, being one of the first examples on the use of peptidomimetics-gold hybrid materials.

  7. Contamination of soil, leaves and vegetables by polychlorinated biphenyls in Xiamen region, China

    Institute of Scientific and Technical Information of China (English)

    MASKAOUI Khalid; ZHOU Jun-liang; HAN Ya-li; HU Zhong; ZHENG Tian-ling; HONG Hua-sheng

    2005-01-01

    The paper aimed to identify the primary of polychlorinated biphenyls(PCBs) in the diulong River Estuary, investigate the spatial distribution of PCBs contamination in the environment, localize the atmospheric source and evaluate ongoing PCBs emissions by analyzing soil samples collected along the Jiulong River region. In addition, the accumulation of PCBs in the human food chain was quantified by analyzing leaf of orange trees and vegetable samples collected along a gradient of soil/atmospheric contamination moving away from the source. Consequently, the impact on the human health and the ecosystem was quantified, different management options were proposedto reduce this impact and to carry out research on organic contaminants along the Jiulong River and Xiamen region.

  8. Yucheng: health effects of prenatal exposure to polychlorinated biphenyls and dibenzofurans.

    Science.gov (United States)

    Guo, Yueliang L; Lambert, George H; Hsu, Chen-Chin; Hsu, Mark M L

    2004-04-01

    Yucheng ("oil-disease") victims were Taiwanese people exposed to polychlorinated biphenyls (PCBs) and their heat-degradation products, mainly polychlorinated dibenzofurans (PCDFs), from the ingestion of contaminated rice oil in 1978-1979. Serial studies in Yucheng offspring born between 1978 and 1992 are summarized. Children of the exposed women were born with retarded growth, with dysmorphic physical findings, and, during development, with delayed cognitive development, increased otitis media, and more behavioral problems than unexposed children. Recently, examination of the reproductive system has suggested that prenatal exposure exerts late effects on semen parameters in young men after puberty. Results of the investigation in Yucheng children will provide important information about the human health effects and toxicology of PCB/PCDF exposure. Prenatal exposure to these environmental chemicals causes the fetus to be sensitive to the toxic effects of persistent organic pollutants.

  9. Mesomorphic, dielectric, and optical properties of fluorosubstituted biphenyls, terphenyls, and quaterphenyls

    Science.gov (United States)

    Kula, P.; Spadło, A.; Dziaduszek, J.; Filipowicz, M.; Dąbrowski, R.; Czub, J.; Urban, S.

    2008-12-01

    Compounds with moderate and large negative dielectric anisotropy (Δɛ) are very attractive liquid crystal (LC) for vertical alignment mode (VA). Materials with such properties can be achieved by lateral substitution of a polar group into a mesogenic molecule. We synthesized some new LC materials with a negative value of Δɛ, a moderately high birefringence (Δn), and a low viscosity. The mesomorphic and physical behaviour of the novel biphenyls, terphenyls and quaterphenyls fluorosubstituted in the rigid core and also with fluorinated alkyl and alkoxy chains are investigated. The prepared series of four LC compounds are promising for new LC mixtures for various applications. Examples of nematic mixtures with Δɛ˜-3.25 will be presented.

  10. (Biphenyl-4-yl)methylammonium chlorides: potent anticonvulsants that modulate Na+ currents.

    Science.gov (United States)

    Lee, Hyosung; Park, Ki Duk; Yang, Xiao-Fang; Dustrude, Erik T; Wilson, Sarah M; Khanna, Rajesh; Kohn, Harold

    2013-07-25

    We have reported that compounds containing a biaryl linked unit (Ar-X-Ar') modulated Na(+) currents by promoting slow inactivation and fast inactivation processes and by inducing frequency (use)-dependent inhibition of Na(+) currents. These electrophysiological properties have been associated with the mode of action of several antiepileptic drugs. In this study, we demonstrate that the readily accessible (biphenyl-4-yl)methylammonium chlorides (compound class B) exhibited a broad range of anticonvulsant activities in animal models, and in the maximal electroshock seizure test the activity of (3'-trifluoromethoxybiphenyl-4-yl)methylammonium chloride (8) exceeded that of phenobarbital and phenytoin upon oral administration to rats. Electrophysiological studies of 8 using mouse catecholamine A-differentiated cells and rat embryonic cortical neurons confirmed that 8 promoted slow and fast inactivation in both cell types but did not affect the frequency (use)-dependent block of Na(+) currents.

  11. Polychlorinated biphenyl toxicity to Japanese quail as related to degree of chlorination

    Science.gov (United States)

    Hill, E.F.; Heath, R.G.; Spann, J.W.; Williams, J.D.

    1974-01-01

    To learn if the percentage of chlorine in a mixture of polychlorinated biphenyls (PCB's) alone determines toxicity, Japanese quail were fed diets containing Aroelor 1248, 1254, or 1260 at levels that added equal amounts of chlorine to the feed. The experiment comprised two consecutive 5-day periods; three sublethal concentrations of chlorine were evaluated during the first period and three lethal concentrations during the second period. Evaluations utilized comparisons of mortality, time to death, weight change, and food consumption. Sublethal concentrations produced no detectable effects. Lethal concentrations with equal Chlorine showed Aroelor 1248 to be less toxic at the highest chlorine concentrations, but at lower concentrations Aroelor 1254 was more toxic than Aroclor 1260. Although chlorine percentage of a PCB is positively correlated with its avian toxicity, PCB toxicity is apparently not simply a function of chlorination.

  12. Effects of pesticides, polychlorinated biphenyls and metals on the growth and reproduction of Acanthamoeba castellanii

    Energy Technology Data Exchange (ETDEWEB)

    Prescott, L.M.; Kubovec, M.K.; Tryggestad, D.

    1977-07-01

    The effects of pollutants (pesticides, PCB and metals) were studied in the free-living amoeba, Acanthamoeba castellanii. Eight pesticides were used--the insecticides dieldrin, aldrin and sevin, and the herbicides linuron, stam F-34, IPC, atrazine and simazine. It was shown that the sensitivity of A. castellanii to pesticides varied greatly. The population growth was inhibited by linuron, stam F-34, IPC, sevin and atrazine at a level of 10 mg/l. The polychlorinated biphenyl, Arochor 1254, had no significant effect at a concentration of 0.01 mg/l (10 ppb). The studies with metal ions showed that A. castellanii was unaffected by moderately high levels of Cu and Zn, but was sensitive to the presence of Pb and mercuric ions.

  13. Effect of polychlorinated biphenyls on spermatogenesis and testosterone secretion in adult cocks

    Institute of Scientific and Technical Information of China (English)

    张才乔; 乔惠理

    2004-01-01

    The effects ofpolychlorinated biphenyls (PCBs) on reproduction of adult cocks were studied by gavaging peanut oil or PCBs (Aroclor 1254, 50 mg/kg) once a week for six consecutive weeks. Physiological parameters were recorded and gonads were removed at the end of experiment for histological examination. The results showed that there was no significant difference between the control and treatment group in body weight, respiration rate, heart rate, body temperature, and the numbers of red and white blood cells. However, there was a marked decrease in the testicular weight and serum testosterone level after PCB treatment. Morphological studies manifested severe damage of the seminiferous tubules by PCB. The number of the germ cells at the different developmental stages was decreased and condensed nuclei were observed in most of these cells. This study revealed that the reproductive function of the adult cocks is sensitive to PCBs, which inhibited mainly spermatogenesis and testosterone secretion.

  14. Electro-optic and dynamic studies of biphenyl benzoate ferroelectric liquid crystals

    Energy Technology Data Exchange (ETDEWEB)

    Hemine, J., E-mail: hemine1@yahoo.f [Laboratoire de Physique de la Matiere Condensee, Universite Hassan II, Mohammedia-Casablanca, BP 146, F.S.T. Mohammedia (Morocco); Daoudi, A. [Universite Lille Nord de France, F-59000 Lille (France); ULCO, LDSMM, F-59140 Dunkerque (France); CNRS UMR8024, F-59140 Dunkerque (France); Legrand, C. [Universite Lille Nord de France, F-59000 Lille (France); ULCO, LEMCEL, F-62228 Calais (France); El kaaouachi, A.; Nafidi, A. [Laboratoire de Physique de la Matiere Condensee, Faculte des Sciences Ibnou Zohr, BP 28/S 80000 Agadir (Morocco); Ismaili, M.; Isaert, N. [Universite Lille Nord de France, F-59000 Lille (France); USTL, LDSMM, F-59655 Villeneuve d' Ascq (France); CNRS UMR8024, F-59655 Villeneuve d' Ascq (France); Nguyen, H.T. [Centre de Recherche Paul Pascal, Universite de Bordeaux 1, 33600 Pessac (France)

    2010-05-01

    We present electro-optic and dynamic properties on three homologous of biphenyl benzoate series of ferroelectric liquid crystals (FLCs) exhibiting the chiral smectic C phase (SmC*). The three compounds present high spontaneous polarization and show the SmC*-SmA*-N* phase sequence. Dielectric spectroscopy was used to provide the dynamics and dipolar ordering of the ferroelectric phase. The Goldstone relaxation mode was studied for sample cells on planar geometry without a DC bias voltage. The rotational viscosity corresponding to molecular motions in the SmC* phase was determined from dielectric measurements. The Arrhenius-type behavior of the rotational viscosity was found and the corresponding activation energies were evaluated.

  15. Rhizospere Redox Cycling and Implications for Rhizosphere Biotransformation of Selected Polychlorinated Biphenyl (PCB) Congeners.

    Science.gov (United States)

    Meggo, Richard E; Schnoor, Jerald L

    2013-08-01

    Theoretically, sequential cycles of dechlorination followed by aerobic bio-oxidation are desirable to achieve complete degradation of a mixture of higher and lower chlorinated PCBs. In this research, soil was artificially contaminated with polychlorinated biphenyls (PCBs) in mixture and as single congeners, aged, and planted with two different plant species. Alternating redox cycles were created in the root zone of plants by flooding and draining the soil. Over 32 weeks, switchgrass (Panicum virgatum) and poplar (Populus deltoids x nigra DN34) planted systems that were exposed to alternate cycles of flooding performed better in reducing parent PCBs than planted systems that were not cycled (p<0.05). The cycled systems also had a higher mass of PCB transformation products than the uncycled systems. Multiple cycles were necessary to achieve significant differences between the cycled and uncycled treatments.

  16. Studies on biphenyl disulphonic acid doped polyanilines: Synthesis, characterization and electrochemistry

    Indian Academy of Sciences (India)

    Chepuri R K Rao; R Muthukannan; M Vijayan

    2012-06-01

    In this article, we report on the results obtained for the efforts we made to bring processability to the conducting polyaniline and substituted polyanilines by designing and synthesizing a new disulphonic acid with a biphenyl moiety as spacer group, viz. 4,4'-biphenyldisulphonic acid (BPSA). When doped, the disulphonic acid acts as a spacer group between the polyaniline chains and facilitates increase in solubility and conductivity. The spacing effect is maximized when BPSA is used as doping agent in in situ polymerization reactions. The conductivity of polyaniline doped by BPSA is 4 S/cm and for the substituted polyanilines it ranged from 2 × 10-5 to 8 × 10-4 S/cm.

  17. [Application prospect about bioremediation of polychlorinated biphenyls-contaminated soil with immobilized microorganism technique: a review].

    Science.gov (United States)

    Hu, Jin-Xing; Su, Xiao-Mei; Han, Hui-Bo; Shen, Chao-Feng; Shi, Ji-Yan

    2014-06-01

    As one type of the persistent organic pollutants, polychlorinated biphenyls (PCBs) are tremendously harmful to organisms. These compounds are easily absorbed onto soil particles and able to accumulate in soil after they are released into the environment. Bioremediation technology of PCBs-contaminated soils has become a research hotspot in recent years, and immobilized microorganism technique has high developing and applying value because of its unique advantages in environmental remediation. This paper reviewed the chief remediation technology of PCBs-contaminated soils and then analyzed the characteristics of immobilized microorganism technique and its research progress in remediation of organic polluted soil. Finally, the feasibility and problems of this technique in remediation of PCBs-contaminated soil were also discussed.

  18. Distribution characteristics of polychlorinated biphenyls (PCBs) in coastal areas of Okinawa Island, Japan

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Surface sediment and seawater samples were collected from coastal areas around Okinawa Island from September 2001 to May 2002. The samples were analyzed for total polychlorinated biphenyl (PCB) levels and homolog composition. The results show that total PCB levels ranged from 0.32 to 128.7 ng/g (dry wt.) in sediment and 1.59 to 2.48 ng/L in seawater. The levels exceed the Environmental Quality Standard (EQS) for water pollution of Japan. The distribution of PCB homolog showed different patterns in the sediments and seawaters. Penta-chlorobiphenyls (CBs) comprised the main congener group in seawater, while hexa-CBs were more abundant homologs in the sediments. The heavily contaminated sites featured higher CBs, including penta-CBs, hexa-CBs, and hepta-CBs, than those in less contaminated sites where tri-CBs dominated. This study provides current distribution and geochemical behavior of PCBs in the coastal areas around Okinawa Island.

  19. Prospects for using combined engineered bacterial enzymes and plant systems to rhizoremediate polychlorinated biphenyls.

    Science.gov (United States)

    Sylvestre, Michel

    2013-03-01

    The fate of polychlorinated biphenyls (PCBs) in soil is driven by a combination of interacting biological processes. Several investigations have brought evidence that the rhizosphere provides a remarkable ecological niche to enhance the PCB degradation process by rhizobacteria. The bacterial oxidative enzymes involved in PCB degradation have been investigated extensively and novel engineered enzymes exhibiting enhanced catalytic activities toward more persistent PCBs have been described. Furthermore, recent studies suggest that approaches involving processes based on plant-microbe associations are very promising to remediate PCB-contaminated sites. In this review emphasis will be placed on the current state of knowledge regarding the strategies that are proposed to engineer the enzymes of the PCB-degrading bacterial oxidative pathway and to design PCB-degrading plant-microbe systems to remediate PCB-contaminated soil.

  20. Polychlorinated biphenyl exposure and glucose metabolism in Danish children aged 9 years

    DEFF Research Database (Denmark)

    Jensen, Tina K; Timmermann, Clara Amalie Gade; Rossing, Laura I;

    2014-01-01

    and participants: A total of 771 healthy Danish third grade school children aged 8-10 years in the municipality of Odense were recruited in 1997 through a two-stage cluster sampling from 25 different schools stratified according to location and socioeconomic character; 509 (9.7±0.8 years, 53% girls) had adequate......Context: Human exposure to polychlorinated biphenyls (PCBs) has been associated to type 2 diabetes in adults. Objectives: To determine whether concurrent serum PCB concentration was associated with markers of glucose metabolism in healthy children. Design: Cross-sectional study. Settings......-DDE. Conclusion: A strong inverse association between serum insulin and PCB exposure was found while fasting plasma glucose remained within the expected narrow range. Our findings suggest that PCB may not exert effect through decreased peripheral insulin sensitivity, as seen in obese and low fit children...

  1. Chromatographic Retention Times of Polychlorinated Biphenyls: from Structural Information to Property Characterization

    Directory of Open Access Journals (Sweden)

    Mircea V. Diudea

    2006-11-01

    Full Text Available The paper presents a unitary approach of the use of a Molecular DescriptorsFamily in structure-property/activity relationships, particularly in modelling thechromatographic retention times of polychlorinated biphenyls. Starting from molecularstructure, viewed as a graph, and considering the bonds and bond types, atom types andoften the 3D geometry of the molecule, a huge family of molecular descriptors called MDFwas calculated. A preliminary selection of MDF members was done by simple linearregression (LR against the measured property. The best fitted MDF subset is thensubmitted to multivariate linear regression (MLR analysis in order to find the best pairs ofMDF members that produce a reliable QSPR (Quantitative Structure-PropertyRelationship model. The predictive capability was finally tested by randomly splitting ofdata into training and test sets. The best obtained models are presented and the results arediscussed.

  2. Relationships between polychlorinated biphenyls in molluscs, hydrological characteristics and human pressures, within Basque estuaries (northern Spain).

    Science.gov (United States)

    Solaun, O; Rodríguez, J G; Borja, A; Larreta, J; Valencia, V

    2015-01-01

    Interannual variability of polychlorinated biphenyls (PCBs), measured in the soft tissues of Mytilus galloprovincialis mussels and Crassostrea gigas oysters, collected from estuarine waters within the Basque Country (Bay of Biscay), are investigated. Samples were collected in the autumn, between 2002 and 2011. Sites located within the ports of Bilbao and Pasaia showed the highest PCBs concentrations in molluscs; the lowest were observed in the mouth of the Oka estuary, an area of low population and industrial activity. Congener profiles of PCBs in the tissues of molluscs reveal the predominance of hexachlorobiphenyls (CB153 and CB138). In addition, redundancy analysis has shown that residence time, river flow and a 'pressure index' explain 57% of the variability in the PCB congener concentrations (the higher the values of these variables, the higher the concentration). Finally, Σ7PCB median concentrations in molluscs and sediments, collected from nearby sampling sites, were found to be moderately correlated (r(2)=0.513, p<0.01).

  3. Improved extraction procedures for polychlorinated biphenyls in solid samples with aqueous sodium hydroxide under autoclave conditions.

    Science.gov (United States)

    Akimoto, Y; Inouye, Y

    2000-03-01

    The efficacy of the extraction of polychlorinated biphenyls (PCBs) from varnish-infiltrated insulating papers as a model of solid materials with an aqueous sodium hydroxide (NaOH) by autoclaving at 121 degrees C for 30 min was compared with those for the conventional procedures, i.e., saponification with 1 N ethanolic NaOH in a boiling water bath for 60 min and extraction with benzene in a Soxhlet apparatus. The newly invented autoclaving method was found to be superior to the conventional ones, yielding approximately 5- to 6-fold cumulative PCB congeners without being accompanied by extended decomposition. Therefore, the autoclave-based sample treatment is recommended for more accurate determination of PCBs in the case of PCB-impregnated solid materials such as hardened oils and resin-coated or -infiltrated papers instead of being treated conventionally.

  4. Dioxins, furans, and polychlorinated biphenyls in hen eggs – a new source of hazard for consumers?

    Directory of Open Access Journals (Sweden)

    Piskorska-Pliszczyńska Jadwiga

    2015-12-01

    Full Text Available The paper presents the results of testing eggs for the content of dioxins and polychlorinated biphenyls (PCBs, determination of the sources that caused the presence of high concentrations of these compounds which exceeded the acceptable contamination levels, and assessment of consumer health risk caused by the consumption of eggs with excessive contents of investigated compounds. In about 9% of free range eggs and 17% of organic eggs, the content of PCDD/Fs was two- or threefold higher than the acceptable limits, and in some samples the concentration of investigated compounds exceeded the maximum concentration levels. Based on the profile of the compounds, it was confirmed in several cases that their main source was the soil or unsecured refuse. The consumers of eggs and meat produced under these conditions constitute the risk groups, and their dioxin and PCB intake may exceed toxicological reference values.

  5. Modelling the impact of room temperature on concentrations of polychlorinated biphenyls (PCBs) in indoor air

    DEFF Research Database (Denmark)

    Lyng, Nadja; Clausen, Per Axel; Lundsgaard, Claus;

    2016-01-01

    Buildings contaminated with polychlorinated biphenyls (PCBs) are a health concern for the building occupants. Inhalation exposure is linked to indoor air concentrations of PCBs, which are known to be affected by indoor temperatures. In this study, a highly PCB contaminated room was heated to six...... temperature levels between 20 and 30 C, i.e. within the normal fluctuation of indoor temperatures, while the air exchange rate was constant. The steady-state air concentrations of seven PCBs were determined at each temperature level. A model based on Clausius–Clapeyron equation, ln(P) = −H/RT + a0, where...... changes in steady-state air concentrations in relation to temperature, was tested. The model was valid for PCB-28, PCB-52 and PCB-101; the four other congeners were sporadic or non-detected. For each congener, the model described a large proportion (R2>94%) of the variation in indoor air PCB levels...

  6. Incubation stage and polychlorinated biphenyl (PCB) congener patterns in an altricial and precocial bird species.

    Science.gov (United States)

    Custer, Christine M; Custer, Thomas W; Thyen, Stefan; Becker, Peter H

    2014-12-01

    The composition of polychlorinated biphenyl (PCB) congeners was compared between non-incubated and embryonated eggs of tree swallows (Tachycineta bicolor) and little terns (Sterna albifrons) to determine if measurable changes in PCB congeners occurred during the embryonic period. There was no indication of changes in PCB congener patterns over the incubation period in tree swallows in 1999 and 2000 at a site with very high PCB exposure or a site with more modest PCB exposure. Additionally, congeners known to be either quickly metabolized or conserved based on experimental studies did not generally respond as predicted. Similarly, PCB congener patterns in eggs of little terns from Bottsand, Schleswig-Holstein, Germany, did not differ between non-incubated and embryonated eggs. The results from both species suggest that the stage of incubation is not an important consideration when evaluating PCB congener patterns; comparisons and assessments can be made with eggs collected at all stages of incubation.

  7. Prediction of mutagenicity and carcinogenicity using in silico modelling: A case study of polychlorinated biphenyls.

    Science.gov (United States)

    Vračko, M; Bobst, S

    2015-01-01

    In silico modelling is an important alternative method for the evaluation of properties of chemical compounds. Basically, two concepts are used in its applications: QSAR modelling for endpoint predictions, and grouping (categorization) of large groups of chemicals. In the presented report we address both of these concepts. As a case study we present the results on a set of polychlorinated biphenyls (PCBs) and some of their metabolites. Their mutagenicity and carcinogenic potency were evaluated with CAESAR and T.E.S.T. models, which are freely available over the internet. We discuss the value and reliability of the predictions, the applicability domain of models and the ability to create prioritized groupings of PCBs as a category of chemicals.

  8. Temperature of hydrogen radio frequency plasma under dechlorination process of polychlorinated biphenyls

    Science.gov (United States)

    Inada, Y.; Abe, K.; Kumada, A.; Hidaka, K.; Amano, K.; Itoh, K.; Oono, T.

    2014-10-01

    It has been reported that RF (radio frequency) hydrogen plasmas promote the dechlorination process of PCBs (polychlorinated biphenyls) under irradiation of MW (microwave). A relative emission intensity spectroscope system was used for single-shot imaging of two-dimensional temperature distributions of RF hydrogen plasmas generated in chemical solutions with several mixing ratios of isopropyl alcohol (IPA) and insulation oil under MW irradiation. Our experimental results showed that the plasma generation frequencies for the oil-contaminating solutions were higher than that for the pure IPA solution. In addition, the plasma temperature in the compound liquids including both oil and IPA was higher than that in the pure IPA and oil solutions. A combination of the plasma temperature measurements and plasma composition analysis indicated that the hydrogen radicals generated in a chemical solution containing the equal volumes of IPA and oil were almost the same amounts of H and H+, while those produced in the other solutions were mainly H.

  9. Polychlorinated biphenyls removal from contaminated soils using a transportable indirect thermal dryer unit: implications for emissions.

    Science.gov (United States)

    Yang, Bing; Xue, Nandong; Ding, Qiong; Vogt, Rolf David; Zhou, Lingli; Li, Fasheng; Wu, Guanglong; Zhang, Shilei; Zhou, Dandan; Liu, Bo; Yan, Yunzhong

    2014-11-01

    An assessment in China of the application of a transportable indirect thermal dryer unit for the remediation of soils contaminated with polychlorinated biphenyls (PCBs) demonstrated that it is well suited to remove PCBs from soils. A remarkable reduction of total PCBs in soils from 163-770 μg g(-1) to 0.08-0.15 μg g(-1) was achieved. This represented removal efficiencies of greater than 99.9% and an approximate 100% removal of the toxic equivalent of the PCBs. Furthermore, the emissions to the atmosphere from the unit were in compliance with current PCBs regulations. In conclusion, remediation of PCBs-contaminated soils based on a transportable indirect thermal dryer unit appears to be a highly efficient and environmentally sound treatment technology that has huge implications for cleaning thousands of regionally dispersed sites of PCBs contamination in China.

  10. QSAR studies of bioconcentration factors of polychlorinated biphenyls (PCBs) using DFT, PCS and CoMFA.

    Science.gov (United States)

    Liu, Hui; Liu, Hongxia; Sun, Ping; Wang, Zunyao

    2014-11-01

    The bioconcentration factors (BCFs) of 58 polychlorinated biphenyls (PCBs) were modeled by quantitative structure-activity relationship (QSAR) using density functional theory (DFT), the position of Cl substitution (PCS) and comparative molecular field analysis (CoMFA) methods. All the models were robust and predictive, and especially, the best CoMFA model was significant with a correlation coefficient (R(2)) of 0.926, a cross-validation correlation coefficient (Q(2)) of 0.821 and a root mean square error estimated (RMSE) of 0.235. The results indicate that the electrostatic descriptors play a more significant role in BCFs of PCBs. Additionally, a test set was used to compare the predictive ability of our models to others, and results show that our CoMFA model present the lowest RMSE. Thus, the models obtain in this work can be used to predict the BCFs of remaining 152 PCBs without available experimental values.

  11. Polychlorinated biphenyl concentrations in adipose tissue and abdominal obesity in the elderly

    DEFF Research Database (Denmark)

    Bräuner, Elvira; Raaschou-Nielsen, Ole; Andersen, Zorana

    2013-01-01

    cessation of smoking, but these do not fully explain the epidemic. Polychlorinated biphenyl congeners (PCBs) are endocrine-disrupting chemicals and evidence from animal experiments suggests an association with obesity development. Our knowledge of the effects of these compounds on weight gain in humans...... is limited. Our objective was to investigate the association between exposure to PCBs experienced by a general Danish population and development of obesity. We randomly selected 204 persons (113 obese and 91 overweight), aged ≥ 50 years, from a prospective Danish cohort of 57,053 persons and examined ten...... PCBs as potential determinants of abdominal obesity. Adipose tissue was collected upon enrolment and PCBs were quantified using gas chromatography-mass spectroscopy. Median levels of the included PCBs were lower in women, except for PCB118 and all PCBs were positively associated with increased...

  12. Growth abnormalities in the population exposed in utero and early postnatally to polychlorinated biphenyls and dibenzofurans

    Energy Technology Data Exchange (ETDEWEB)

    Yueliang L. Guo; Chen-Chin Hsu [National Cheng Kung Univ. Medical College, Tainan (Taiwan, Province of China); Lambert, G.H. [UMDNJ-Robert Wood Johnson Medical School, New Brunswick, NJ (United States)

    1995-09-01

    This article reviews the findings in children exposed to various levels of polychlorinated biphenyls (PCBs) and related compounds in utero and early postnatally. Yu-Cheng ({open_quotes}oil-disease{close_quotes}) mothers were Taiwanese women exposed to PCBs and their heat-degradation products form the ingestion of contaminated rice oil in 1979. Children of these mothers were born growth retarded, with dysmorphic physical findings, and delayed cognitive development compared with unexposed children. In this article, findings in Yu-Cheng children born between 1978 and 1985 are summarized and compared with two other well-documented cohorts of children prenatally exposed to different levels of PCBs. Results of the investigation in Yu-Cheng children will provide important information about the toxicities, health effects, and mechanisms of PCB/PCDF exposure and demonstrate that the developing human is more sensitive than the adult to the toxic effects of these chemicals. 53 refs., 2 tabs.

  13. Persistent organochlorine residues and toxic evaluation of polychlorinated biphenyls in sharks from the Mediterranean Sea (Italy)

    Energy Technology Data Exchange (ETDEWEB)

    Storelli, M.M.; Marcotrigiano, G.O. [Bari Univ., Dip. Farmaco-Biologico, Bari (Italy)

    2001-07-01

    Persistent organochlorines such as polychlorinated biphenyls including coplanar congeners, DDT compounds and HCB were measured in different tissues (muscle, liver and eggs) of two Mediterranean shark species: namely Centrophorus granulosus and Squalus blainvillei. The concentrations of organochlorines in the tissues and organs of both species were in the order DDTs>PCBs>HCB. The highest values of DDTs, PCBs and HCB were found in liver followed by eggs and muscle. Among DDTs the compound found in greatest concentration was p,p -DDE. The PCB profiles were dominated by congeners 138, 153, and 180. The isomers with higher TEQs values were non- and mono-ortho congeners than di-ortho ones in muscle, liver and eggs of both species. Among the non-ortho, PCB 126 was the major contributing individual to the total TEQs in both species. (Author)

  14. Digestive tract absorption of polychlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyls in a nursing infant

    Energy Technology Data Exchange (ETDEWEB)

    McLachlan, M.S. (Univ. of Bayreuth (Germany))

    1993-11-01

    The digestive tract absorption of environmental contaminants is an important but poorly understood parameter in contaminant is an important but poorly understood parameter in contaminant risk assessments. The net absorption of polychlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyls in a nursing infant was measured under natural conditions over 12 days. The levels of the substances in the mother's milk were typical for Germany. It was found that for almost all congeners over 90% of the ingested compound was absorbed. This indicates that the common assumption of 100% absorption in nursing infants is reasonable. No firm conclusions could be drawn regarding the absorption of Cl7- and Cl8DD/F due to high blank levels in the cotton diapers used.

  15. Molecular perspectives and recent advances in microbial remediation of persistent organic pollutants.

    Science.gov (United States)

    Chakraborty, Jaya; Das, Surajit

    2016-09-01

    Nutrition and pollution stress stimulate genetic adaptation in microorganisms and assist in evolution of diverse metabolic pathways for their survival on several complex organic compounds. Persistent organic pollutants (POPs) are highly lipophilic in nature and cause adverse effects to the environment and human health by biomagnification through the food chain. Diverse microorganisms, harboring numerous plasmids and catabolic genes, acclimatize to these environmentally unfavorable conditions by gene duplication, mutational drift, hypermutation, and recombination. Genetic aspects of some major POP catabolic genes such as biphenyl dioxygenase (bph), DDT 2,3-dioxygenase, and angular dioxygenase assist in degradation of biphenyl, organochlorine pesticides, and dioxins/furans, respectively. Microbial metagenome constitutes the largest genetic reservoir with miscellaneous enzymatic activities implicated in degradation. To tap the metabolic potential of microorganisms, recent techniques like sequence and function-based screening and substrate-induced gene expression are proficient in tracing out novel catabolic genes from the entire metagenome for utilization in enhanced biodegradation. The major endeavor of today's scientific world is to characterize the exact genetic mechanisms of microbes for bioremediation of these toxic compounds by excavating into the uncultured plethora. This review entails the effect of POPs on the environment and involvement of microbial catabolic genes for their removal with the advanced techniques of bioremediation.

  16. Assessment of polychlorinated biphenyls and organochlorine pesticides in water samples from the Yamuna River

    Directory of Open Access Journals (Sweden)

    Bhupander Kumar

    2012-07-01

    Full Text Available Polychlorinated biphenyls (PCBs, hexachlorocyclohexane (HCH and dichlorodiphenyltrichloroethane (DDT are toxic, persistent and bioaccumulative long-range atmospheric transport pollutants. These are transported worldwide affecting remote regions far from their original sources, and can transfer into food webs with a wide range of acute and chronic health effects. India ratified the Stockholm Convention with the intention of reducing and eliminating persistent organic pollutants (POPs, and encouraged the support of research on POPs. Despite the ban and restriction on the use of these chemicals in India, their contamination of air, water, sediment, biota and humans has been reported. In this study, surface water samples were collected during January 2012 from the Yamuna River in Delhi, India, and analyzed for PCBs and organochlorine pesticides (OCPs. The concentrations of ΣPCBs and ΣOCPs ranged between 2-779 ng L–1 and from less than 0.1 to 618 ng L–1 (mean 99±38 ng L–1 and 221±50 ng L–1, respectively. The PCB homolog was dominated by 3-4 chlorinated biphenyls. In calculating the toxicity equivalent of dioxin-like PCBs (dl-PCBsusing World Health Organization toxic equivalency factors, dl-PCBs accounted for 10% of a total of 27 PCBs. The concentration of ΣHCH ranged between less than 0.1 and 285 ng L–1 (mean 151±32 ng L–1. However, ΣDDTs concentrations varied between less than 0.1 and 354 ng L–1 (mean 83±26 ng L–1. The concentrations were lower than the US guideline values; however, levels of lindane exceeded those recommended in guidelines. Further in-depth study is proposed to determine the bioaccumulation of these pollutants through aquatic biota to assess the risk of contaminants to human health.

  17. Microwave-assisted steam distillation for simple determination of polychlorinated biphenyls and organochlorine pesticides in sediments.

    Science.gov (United States)

    Numata, Masahiko; Yarita, Takashi; Aoyagi, Yoshie; Takatsu, Akiko

    2003-03-15

    A novel sample extraction technique for polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) analysis using microwave-heating device is developed. In this study, microwave-assisted extraction (MAE) and steam distillation techniques were combined. Desorption of the anatytes from solid matrixes was accelerated with water vapor which was generated by microwave irradiation. A sample holder in a commercial microwave extraction cell kept the sample from direct contact with the organic solvent for analytes trapping during the treatment process. Therefore, relatively clean extracts were obtained with small amount of solvents. Without any cleanup steps, the obtained extract could be analyzed with gas chromatograph/mass spectrometers (GC/MS). Six PCB congeners (PCB15, 28, 70, 101, 180, 194, 209) and three OCPs (gamma-HCH, 4,4'-DDE, 4,4'-DDD) in two marine sediment samples (a sediment collected from a bay of Kyusyu Island, Japan, and a certified reference material NIST SRM1944) were analyzed by using this microwave-assisted steam distillation (MASD) technique and another extraction method (exhaustive steam distillation, MAE, and Soxhlet extraction); and comparisons of the results are shown in this report. Although recovery yields of highly chlorinated biphenyls (PCB180, 194, 209) and relatively polar OCPs (gamma-HCH, 4,4'-DDD) were low (30-60%) compared with other analytes (PCB15, 28, 70, 101, 4,4'-DDE; recovery, 80-100%), use of isotope labeled internal standards for the MASD technique gave comparable results with the values obtained by other extraction methods and the certified values in the samples.

  18. Identification of a gene cluster associated with triclosan catabolism.

    Science.gov (United States)

    Kagle, Jeanne M; Paxson, Clayton; Johnstone, Precious; Hay, Anthony G

    2015-06-01

    Aerobic degradation of bis-aryl ethers like the antimicrobial triclosan typically proceeds through oxygenase-dependent catabolic pathways. Although several studies have reported on bacteria capable of degrading triclosan aerobically, there are no reports describing the genes responsible for this process. In this study, a gene encoding the large subunit of a putative triclosan oxygenase, designated tcsA was identified in a triclosan-degrading fosmid clone from a DNA library of Sphingomonas sp. RD1. Consistent with tcsA's similarity to two-part dioxygenases, a putative FMN-dependent ferredoxin reductase, designated tcsB was found immediately downstream of tcsA. Both tcsAB were found in the midst of a putative chlorocatechol degradation operon. We show that RD1 produces hydroxytriclosan and chlorocatechols during triclosan degradation and that tcsA is induced by triclosan. This is the first study to report on the genetics of triclosan degradation.

  19. Association between exposure to dioxin-like polychlorinated biphenyls and miR-191 expression in human peripheral blood mononuclear cells.

    Science.gov (United States)

    Guida, Maurizio; Marra, Maria Luisa; Marra, Marialuisa; Zullo, Fulvio; Guida, Marco; Trifuoggi, Marco; Biffali, Elio; Borra, Marco; De Mieri, Giovanna; D'Alessandro, Raffaella; De Felice, Bruna

    2013-04-30

    Accumulating evidence shows an association between deregulation of miRNAs and exposure to environmental chemicals; miRNAs play a unique regulatory role in gene expression. Among environmental pollutants, dioxins are a family of compounds that are known to have multiple hazardous effects. Also, in utero exposure of the fetus to dioxins has been shown to cause impaired psychomotor development, decreased immune function and skin disease. miR-191 is a microRNA that has been found to be up-regulated by dioxin in hepatocellular carcinoma cells in vitro. Our study provides the first molecular evidence in vivo of a positive relationship between levels of polychlorinated biphenyls (PCBs) and miR-191 expression in human peripheral blood mononuclear cells. miR-191 expression was significantly correlated with blood concentrations of total PCB and, in particular, of 3,3',4,4',5,5'-hexachlorobiphenyl (PCB 169, a coplanar congener). Blood concentrations of PCB 169 correlated significantly with miR-191 expression in pregnant women living in a PCB-polluted area, who underwent therapeutic abortion due to fetal malformations. These data suggest that miRNAs could be potential biomarkers to clarify the mechanisms of environmental disease.

  20. Augmented atherogenesis in ApoE-null mice co-exposed to polychlorinated biphenyls and 2,3,7,8-tetrachlorodibenzo-p-dioxin.

    Science.gov (United States)

    Shan, Qiuli; Wang, Jing; Huang, Fengchen; Lv, Xiaowen; Ma, Min; Du, Yuguo

    2014-04-15

    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and polychlorinated biphenyls (PCBs) are persistent organic pollutants found as complex mixtures in the environment throughout the world. Therefore, humans are ubiquitously and simultaneously exposed to TCDD and PCBs. TCDD and PCBs alone have been linked to atherosclerosis. However, the effects of interactions or synergism between TCDD and PCBs on atherogenesis are unknown. We investigated the possible enhanced atherogenesis by co-exposure to TCDD and PCBs and the potential mechanism(s) involved in this enhancement. Male ApoE(-/-) mice were exposed to TCDD (15 μg/kg) and Aroclor1254 (55 mg/kg, a representative mixture of PCBs) alone or in combination by intraperitoneal injection four times over six weeks of duration. Our results showed that mice exposed to TCDD alone, but not Aroclor1254 alone, developed atherosclerotic lesions. Moreover, we found that atherosclerotic disease was exacerbated to the greatest extent in mice co-exposed to TCDD and Aroclor1254. The enhanced lesions correlated with several pro-atherogenic changes, including a marked increase in the accumulation of the platelet-derived chemokine PF4, and the expression of the proinflammatory cytokine MCP-1 and the critical immunity gene-RIG-I. Our data demonstrated that co-exposure to TCDD and Aroclor1254 markedly enhanced atherogenesis in ApoE(-/-) mice. Significantly, our observations suggest that combined exposure to TCDD and PCBs may be a greater cardiovascular health risk than previously anticipated from individual studies.

  1. A cohort study of the association between secondary sex ratio and parental exposure to polybrominated biphenyl (PBB and polychlorinated biphenyl (PCB

    Directory of Open Access Journals (Sweden)

    Terrell Metrecia L

    2009-08-01

    Full Text Available Abstract Background Polybrominated biphenyl (PBB, a brominated flame retardant, was accidently mixed into animal feed in Michigan (1973–1974 resulting in human exposure through consumption of contaminated meat, milk and eggs. Beginning in 1976 individuals who consumed contaminated products were enrolled in the Michigan Long-Term PBB Study. This cohort presents a unique opportunity to study the association between parental exposures to PBB and offspring sex ratio. Methods We identified offspring of female PBB cohort participants (born 1975–1988 and obtained electronic birth records for those born in the state of Michigan. We linked this information to parental serum PBB and PCB concentrations collected at enrollment into the cohort. We modeled the odds of a male birth with generalized estimating equations accounting for the non-independence of siblings born to the same parents. We explored potential confounders: parental age and education at offspring's birth, parental body mass index at cohort enrollment, birth order, gestational age and year of offspring's birth. Results The overall proportion of male offspring among 865 live births to cohort mothers was 0.542. This was higher than the national male proportion of 0.514 (binomial test: p = 0.10. When both parents were in the cohort (n = 300, we found increased odds of a male birth with combined parents' enrollment PBB exposure ≥ the median concentrations (3 μg/L for mothers; 6 μg/L for fathers compared to combined parents' PBB exposure Conclusion This study adds to the body of literature on secondary sex ratio and exposure to environmental contaminants. In this population, combined parental exposure to PBBs or PCBs increased the odds of a male birth. Further research is needed to corroborate these findings and shed light on the biological mechanisms by which these types of chemicals may influence the secondary sex ratio.

  2. Polychlorinated biphenyls and hydroxylated polychlorinated biphenyls in plasma of bottlenose dolphins (Tursiops truncatus) from the Western Atlantic and the Gulf of Mexico.

    Science.gov (United States)

    Houde, Magali; Pacepavicius, Grazina; Wells, Randall S; Fair, Patricia A; Letcher, Robert J; Alaee, Mehran; Bossart, Gregory D; Hohn, Aleta A; Sweeney, Jay; Solomon, Keith R; Muir, Derek C G

    2006-10-01

    Polychlorinated biphenyls (PCBs) and hydroxylated metabolic products (OH-PCBs) were measured in plasma collected from live-captured and released bottlenose dolphins (Tursiops truncatus) from five different locations in the Western Atlantic and the Gulf of Mexico in 2003 and 2004. In 2004, the sum (sigma) of concentration of PCBs in plasma of dolphins sampled off Charleston, SC [geometric mean: 223 ng/g of wet weight (w.w.)] was significantly higher (pRiver Lagoon, FL (sigmaPCBs: 122 ng/g w.w.) and the Sarasota Bay, FL (sigmaPCBs: 111 ng/g w.w.). The PCB homolog profiles were similar among locations. Concentrations of OH-PCBs were significantly higher (p<0.05) in plasma of dolphins from Charleston, SC (sigmaOH-PCBs for 2003: 126 ng/g w.w.; 2004: 138 ng/g w.w.) than animals from Florida (sigmaOH-PCBs ranged from 6 to 47 ng/g w.w.) and Bermuda (8.3 ng/g w.w.); however, concentrations in the Charleston samples did not differ from animals captured in Delaware Bay, NJ (57 ng/g w.w.). The sigmaOH-PCBs constituted 2-68% of the total PCB concentrations in plasma. Dichloro- to nonachloro-OH-PCBs were quantified using high-resolution gas chromatography mass spectrometry, but only around 20% of OH-PCBs could be identified by comparison to authentic standards. Results from this study show that OH-PCB are important environmental contaminants in dolphins and suggest that PCBs, decades after their ban, may still constitute a threat to wildlife.

  3. Design, synthesis, pharmacological evaluation and computational studies of 1-(biphenyl-4-yl)-2-[4-(substituted phenyl)-piperazin-1-yl]ethanones as potential antipsychotics.

    Science.gov (United States)

    Bhosale, Sharad H; Kanhed, Ashish M; Dash, Radha Charan; Suryawanshi, Mugdha R; Mahadik, K R

    2014-03-03

    This article describes the design of biphenyl moiety linked with aryl piperazine and syntheses of fourteen 1-(biphenyl-4-yl)-2-[4-(substituted phenyl)-piperazin-1-yl]ethanone derivatives along with their pharmacological evaluation for antipsychotic activity and computational studies including quantitative structure activity relationship (QSAR) and descriptor based similarity study. All compounds were found to exhibit considerable anti-dopaminergic and anti-serotonergic activity in behavioural models. Among all derivatives, compound 1-(biphenyl-4-yl)-2-[4-(2-methoxyphenyl)-piperazin-1-yl]ethanone (3c) and 1-(biphenyl-4-yl)-2-[4-(2,3-dichlorophenyl)-piperazin-1-yl]ethanone (3k) showed impressive antipsychotic profile with lower potency for catalepsy induction. These results were found to be sturdily matching with docking study in designing of compounds with homology model of human dopamine D2 receptor. Also the QSAR study strongly supports the obtained results.

  4. 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

    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.

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

    Science.gov (United States)

    Reuter, Klaus; Pittelkow, Marco; Bursy, Jan; Heine, Andreas; Craan, Tobias; Bremer, Erhard

    2010-05-14

    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.

  6. 4-nitrocatechol as a probe of a Mn(II)-dependent extradiol-cleaving catechol dioxygenase (MndD): comparison with relevant Fe(II) and Mn(II) model complexes.

    Science.gov (United States)

    Reynolds, Mark F; Costas, Miquel; Ito, Masami; Jo, Du-Hwan; Tipton, A Alex; Whiting, Adam K; Que, Lawrence

    2003-02-01

    Mn(II)-dependent 3,4-dihydroxyphenylacetate 2,3-dioxygenase (MndD) is an extradiol-cleaving catechol dioxygenase from Arthrobacter globiformis that has 82% sequence identity to and cleaves the same substrate (3,4-dihydroxyphenylacetic acid) as Fe(II)-dependent 3,4-dihydroxyphenylacetate 2,3-dioxygenase (HPCD) from Brevibacterium fuscum. We have observed that MndD binds the chromophoric 4-nitrocatechol (4-NCH(2)) substrate as a dianion and cleaves it extremely slowly, in contrast to the Fe(II)-dependent enzymes which bind 4-NCH(2) mostly as a monoanion and cleave 4-NCH(2) 4-5 orders of magnitude faster. These results suggest that the monoanionic binding state of 4-NC is essential for extradiol cleavage. In order to address the differences in 4-NCH(2) binding to these enzymes, we synthesized and characterized the first mononuclear monoanionic and dianionic Mn(II)-(4-NC) model complexes as well as their Fe(II)-(4-NC) analogs. The structures of [(6-Me(2)-bpmcn)Fe(II)(4-NCH)](+), [(6-Me(3)-TPA)Mn(II)(DBCH)](+), and [(6-Me(2)-bpmcn)Mn(II)(4-NCH)](+) reveal that the monoanionic catecholate is bound in an asymmetric fashion (Delta r(metal-O(catecholate))=0.25-0.35 A), as found in the crystal structures of the E(.)S complexes of extradiol-cleaving catechol dioxygenases. Acid-base titrations of [(L)M(II)(4-NCH)](+) complexes in aprotic solvents show that the p K(a) of the second catecholate proton of 4-NCH bound to the metal center is half a p K(a) unit higher for the Mn(II) complexes than for the Fe(II) complexes. These results are in line with the Lewis acidities of the two divalent metal ions but are the opposite of the trend observed for 4-NCH(2) binding to the Mn(II)- and Fe(II)-catechol dioxygenases. These results suggest that the MndD active site decreases the second p K(a) of the bound 4-NCH(2) relative to the HPCD active site.

  7. Analysis on differentially expressed genes in watermelon rind color based on RNA-Seq

    Institute of Scientific and Technical Information of China (English)

    杨侃侃; 梁志怀; 吴才君

    2016-01-01

    In order to screen the genes controlling watermelon rind color and luster, the experiment was carried out with yellow watermelon skin mutants as tester and green wild type watermelon as control, and transcriptome sequencing and bioinformatics analysis were done. The results show that 34.27Gb clean data were got by transcriptome sequencing. There are 261 differentially expressed genes among Y1_vs_G1, Y2_vs_G2 and Y3_vs_G3.The pathways contenting most differentially expressed genes are plant hormone signal transduction pathway, phenylpropanoid biosynthesis pathway, photosynthesis pathway, starch and sucrose metabolism pathway. 9-cis-epoxycarotenoid dioxygenase (Cla002942), alcohol dehydrogenase (Cla004992), photosystem I reaction center subunit III, chloroplastic (precursor) (Cla009181), long-chain acyl coenzyme A synthetase (Cla017341), threonine dehydratase biosynthetic (Cla018352) candidates genes were screened out.

  8. Genes and Gene Therapy

    Science.gov (United States)

    ... correctly, a child can have a genetic disorder. Gene therapy is an experimental technique that uses genes to ... or prevent disease. The most common form of gene therapy involves inserting a normal gene to replace an ...

  9. Poly(meta-phenylene) Derivative with Rigid Twisted Biphenyl Units in Backbone: Synthesis, Structural Characterization,Photophysical Properties and Electroluminescence

    Institute of Scientific and Technical Information of China (English)

    ZHENG Yan; YANG Bing; ZHANG Hai-quan; LU Ping; SHEN Fang-zhong; LIU Lin-lin; XU Hai; YANG Guang-di; MA Yu-guang

    2007-01-01

    A soluble poly(meta-phenylene) derivative with rigid twisted biphenyl unit was synthesized by the Yamamoto coupling reaction. The polymer is soluble in common organic solvents, and the number-average molecular weight is about 6500. The UV-Vis and quantum chemical calculation indicate that the different conformation segments named "conformers" exist in the polymer backbones; it was also further confirmed by the single crystal X-ray diffraction study of the dimeric model compound. The π-π* transition of biphenyl segments of twisted and planar conformations made the polymer exhibit a strong absorption around 256 nm and a weak absorption at about 300 nm. Furthermore,the polymer exhibits a strong UV photoluminescence at 372 nm when the excitation wavelengths are longer than 300 nm. The ultraviolet-emitting electroluminescence(EL) device with the single layer structure shows EL λmax of the derivative at 370 nm.

  10. Enhanced reductive dechlorination of polychlorinated biphenyl-contaminated soil by in-vessel anaerobic composting with zero-valent iron.

    Science.gov (United States)

    Long, Yu-Yang; Zhang, Chi; Du, Yao; Tao, Xiao-Qing; Shen, Dong-Sheng

    2014-03-01

    Anaerobic dechlorination is an effective degradation pathway for higher chlorinated polychlorinated biphenyls (PCBs). The enhanced reductive dechlorination of PCB-contaminated soil by anaerobic composting with zero-valent iron (ZVI) was studied, and preliminary reasons for the enhanced reductive dechlorination with ZVI were investigated. The results show that the addition of nanoscale ZVI can enhance dechlorination during in-vessel anaerobic composting. After 140 days, the average number of removed Cl per biphenyl with 10 mg g(-1) of added nanoscale ZVI was 0.63, enhancing the dechlorination by 34 % and improving the initial dechlorination speed. The ZVI enhances dechlorination by providing a suitable acid base environment, reducing volatile fatty acid inhibition and stimulating the microorganisms. The C/N ratios for treatments with the highest rate of ZVI addition were smaller than for the control, indicating that ZVI addition can promote compost maturity.

  11. Biodegradation of phenanthrene, spatial distribution of bacterial populations and dioxygenase expression in the mycorrhizosphere of Lolium perenne inoculated with Glomus mosseae.

    Science.gov (United States)

    Corgié, S C; Fons, F; Beguiristain, T; Leyval, C

    2006-05-01

    Interactions between the plant and its microbial communities in the rhizosphere control microbial polycyclic aromatic hydrocarbons (PAH) biodegradation processes. Arbuscular mycorrhizal (AM) fungi can influence plant survival and PAH degradation in polluted soil. This work was aimed at studying the contribution of the mycorrhizosphere to PAH biodegradation in the presence of ryegrass (Lolium perenne L., cv. Barclay) inoculated with Glomus mosseae (BEG 69) by taking into account the structure and activity of bacterial communities, PAH degrading culturable bacteria as a function of the distance from roots. Ryegrass was grown in compartmentalized systems designed to harvest successive sections of rhizosphere in lateral compartments polluted or not with phenanthrene (PHE). Colonization of roots by G. mosseae (BEG 69) modified the structure and density of bacterial populations in the mycorrhizosphere, compared to the rhizosphere of non-mycorrhizal plants. G. mosseae increased the density of culturable heterotrophic and PAH degrading bacteria beyond the immediate rhizosphere in the presence of PHE, and increased the density of PAH degraders in the absence of the pollutant. Biodegradation was not significantly increased in the mycorrhizosphere, compared to control non-mycorrhizal plants, where PHE biodegradation already reached 92% after 6 weeks. However, dioxygenase transcriptional activity was found to be higher in the immediate mycorrhizosphere in the presence of G. mosseae (BEG 69).

  12. Oral Probiotic VSL#3 Prevents Autoimmune Diabetes by Modulating Microbiota and Promoting Indoleamine 2,3-Dioxygenase-Enriched Tolerogenic Intestinal Environment

    Directory of Open Access Journals (Sweden)

    Jayashree Dolpady

    2016-01-01

    Full Text Available The gut microbiota modulates the autoimmune pathogenesis of type 1 diabetes (T1D via mechanisms that remain largely unknown. The inflammasome components are innate immune sensors that are highly influenced by the gut environment and play pivotal roles in maintaining intestinal immune homeostasis. In this study we show that modifications of the gut microbiota induced by oral treatment with Lactobacillaceae-enriched probiotic VSL#3, alone or in combination with retinoic acid (RA, protect NOD mice from T1D by affecting inflammasome at the intestinal level. In particular, we show that VSL#3 treatment inhibits IL-1β expression while enhancing release of protolerogenic components of the inflammasome, such as indoleamine 2,3-dioxygenase (IDO and IL-33. Those modifications of the intestinal microenvironment in VSL#3-treated NOD mice modulate gut immunity by promoting differentiation of tolerogenic CD103+ DCs and reducing differentiation/expansion of Th1 and Th17 cells in the intestinal mucosa and at the sites of autoimmunity, that is, within the pancreatic lymph nodes (PLN of VSL#3-treated NOD mice. Our data provide a link between dietary factors, microbiota composition, intestinal inflammation, and immune homeostasis in autoimmune diabetes and could pave the way for new therapeutic approaches aimed at changing the intestinal microenvironment with probiotics to counterregulate autoimmunity and prevent T1D.

  13. Engineering catechol 1, 2-dioxygenase by design for improving the performance of the cis, cis-muconic acid synthetic pathway in Escherichia coli

    Science.gov (United States)

    Han, Li; Liu, Pi; Sun, Jixue; Wu, Yuanqing; Zhang, Yuanyuan; Chen, Wujiu; Lin, Jianping; Wang, Qinhong; Ma, Yanhe

    2015-01-01

    Regulating and ameliorating enzyme expression and activity greatly affects the performance of a given synthetic pathway. In this study, a new synthetic pathway for cis, cis-muconic acid (ccMA) production was reconstructed without exogenous induction by regulating the constitutive expression of the important enzyme catechol 1,2-dioxygenase (CatA). Next, new CatAs with significantly improved activities were developed to enhance ccMA production using structure-assisted protein design. Nine mutations were designed, simulated and constructed based on the analysis of the CatA crystal structure. These results showed that mutations at Gly72, Leu73 and/or Pro76 in CatA could improve enzyme activity, and the activity of the most effective mutant was 10-fold greater than that of the wild-type CatA from Acinetobacter sp. ADP1. The most productive synthetic pathway with a mutated CatA increased the titer of ccMA by more than 25%. Molecular dynamic simulation results showed that enlarging the entrance of the substrate-binding pocket in the mutants contributed to their increased enzyme activities and thus improved the performance of the synthetic pathway. PMID:26306712

  14. Detailed analysis and follow-up studies of a high-throughput screening for indoleamine 2,3-dioxygenase 1 (IDO1) inhibitors.

    Science.gov (United States)

    Röhrig, Ute F; Majjigapu, Somi Reddy; Chambon, Marc; Bron, Sylvian; Pilotte, Luc; Colau, Didier; Van den Eynde, Benoît J; Turcatti, Gerardo; Vogel, Pierre; Zoete, Vincent; Michielin, Olivier

    2014-09-12

    Indoleamine 2,3-dioxygenase 1 (IDO1) is a key regulator of immune responses and therefore an important therapeutic target for the treatment of diseases that involve pathological immune escape, such as cancer. Here, we describe a robust and sensitive high-throughput screen (HTS) for IDO1 inhibitors using the Prestwick Chemical Library of 1200 FDA-approved drugs and the Maybridge HitFinder Collection of 14,000 small molecules. Of the 60 hits selected for follow-up studies, 14 displayed IC50 values below 20 μM under the secondary assay conditions, and 4 showed an activity in cellular tests. In view of the high attrition rate we used both experimental and computational techniques to identify and to characterize compounds inhibiting IDO1 through unspecific inhibition mechanisms such as chemical reactivity, redox cycling, or aggregation. One specific IDO1 inhibitor scaffold, the imidazole antifungal agents, was chosen for rational structure-based lead optimization, which led to more soluble and smaller compounds with micromolar activity.

  15. Early carcinogenesis involves the establishment of immune privilege via intrinsic and extrinsic regulation of Indoleamine 2,3-dioxygenase-1: Translational implications in cancer immunotherapy

    Directory of Open Access Journals (Sweden)

    Alisha eHoltzhausen

    2014-10-01

    Full Text Available Although prolonged genetic pressure has been conjectured to be necessary for the eventual development of tumor immune evasion mechanisms, recent work is demonstrating that early genetic mutations are capable of moonlighting as both intrinsic and extrinsic modulators of the tumor immune microenvironment. The indoleamine 2,3-dioxygenase-1 (IDO immunoregulatory enzyme is emerging as a key player in tumor-mediated immune tolerance. While loss of the tumor suppressor, BIN-1, and the over-expression of cyclooxygenase-2 (COX-2 have been implicated in intrinsic regulation of IDO, recent findings have demonstrated the loss of TβRIII and the upregulation of Wnt5a by developing cancers to play a role in the extrinsic control of IDO activity by local dendritic cell populations residing within tumor and tumor-draining lymph node tissues. Together, these genetic changes are capable of modulating paracrine signaling pathways in the early stages of carcinogenesis to establish a site of immune privilege by promoting the differentiation and activation of local regulatory T cells. Additional investigation of these immune evasion pathways promises to provide opportunities for the development of novel strategies to synergistically enhance the efficacy of the evolving class of T cell-targeted ‘checkpoint’ inhibitors.

  16. Effects of various phytochemicals on indoleamine 2,3-dioxygenase 1 activity: galanal is a novel, competitive inhibitor of the enzyme.

    Directory of Open Access Journals (Sweden)

    Rie Yamamoto

    Full Text Available 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.

  17. Intracerebroventricular Administration of Streptozotocin as an Experimental Approach to Depression: Evidence for the Involvement of Proinflammatory Cytokines and Indoleamine-2,3-Dioxygenase.

    Science.gov (United States)

    Souza, Leandro Cattelan; Jesse, Cristiano R; de Gomes, Marcelo Gomes; Viana, Cristini Escobar; Mattos, Etiara; Silva, Neici Cáceres; Boeira, Silvana Peterini

    2017-02-02

    There is a lack of information about the molecular events underlying the depressive-like effect of an intracerebroventricular injection of streptozotocin (ICV-STZ) in mice. Elevated activity of the tryptophan-degrading enzyme indoleamine-2,3-dioxygenase (IDO) has been proposed to mediate depression in inflammatory disorders. In this study, we report that ICV-STZ activates IDO in the hippocampus of mice and culminates in depressive-like behaviors, measured by an increased duration in immobility time in the forced swimming test and decreased total time of grooming in the splash test. Indirect blockade of IDO activation with the cytokine inhibitor minocycline prevents the development of depressive-like behaviors and attenuates STZ-induced upregulation of proinflammatory cytokines in the hippocampus. Minocycline abrogates the increase in tryptophan and kynurenine levels as well as prevents serotonin dysfunction in the hippocampus of STZ-injected mice. These results suggest that hippocampal IDO activation in STZ-associated depressive-like behavior is mediated by proinflammatory cytokine-dependent mechanisms. Our study not only extends the evidence that IDO has a critical role in mediating inflammation-induced depression but also supports the notion that neuroinflammation and the kynurenine pathway are important targets of novel therapeutic drugs for depression. In addition, our study provides new insights into the neurobiological mechanisms underlying ICV-STZ and indicates that this model could be employed in the preclinical research of depression.

  18. 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.

  19. Primary hepatocytes from mice lacking cysteine dioxygenase show increased cysteine concentrations and higher rates of metabolism of cysteine to hydrogen sulfide and thiosulfate.

    Science.gov (United States)

    Jurkowska, Halina; Roman, Heather B; Hirschberger, Lawrence L; Sasakura, Kiyoshi; Nagano, Tetsuo; Hanaoka, Kenjiro; Krijt, Jakub; Stipanuk, Martha H

    2014-05-01

    The oxidation of cysteine in mammalian cells occurs by two routes: a highly regulated direct oxidation pathway in which the first step is catalyzed by cysteine dioxygenase (CDO) and by desulfhydration-oxidation pathways in which the sulfur is released in a reduced oxidation state. To assess the effect of a lack of CDO on production of hydrogen sulfide (H2S) and thiosulfate (an intermediate in the oxidation of H2S to sulfate) and to explore the roles of both cystathionine γ-lyase (CTH) and cystathionine β-synthase (CBS) in cysteine desulfhydration by liver, we investigated the metabolism of cysteine in hepatocytes isolated from Cdo1-null and wild-type mice. Hepatocytes from Cdo1-null mice produced more H2S and thiosulfate than did hepatocytes from wild-type mice. The greater flux of cysteine through the cysteine desulfhydration reactions catalyzed by CTH and CBS in hepatocytes from Cdo1-null mice appeared to be the consequence of their higher cysteine levels, which were due to the lack of CDO and hence lack of catabolism of cysteine by the cysteinesulfinate-dependent pathways. Both CBS and CTH appeared to contribute substantially to cysteine desulfhydration, with estimates of 56 % by CBS and 44 % by CTH in hepatocytes from wild-type mice, and 63 % by CBS and 37 % by CTH in hepatocytes from Cdo1-null mice.

  20. Oral Probiotic VSL#3 Prevents Autoimmune Diabetes by Modulating Microbiota and Promoting Indoleamine 2,3-Dioxygenase-Enriched Tolerogenic Intestinal Environment.

    Science.gov (United States)

    Dolpady, Jayashree; Sorini, Chiara; Di Pietro, Caterina; Cosorich, Ilaria; Ferrarese, Roberto; Saita, Diego; Clementi, Massimo; Canducci, Filippo; Falcone, Marika

    2016-01-01

    The gut microbiota modulates the autoimmune pathogenesis of type 1 diabetes (T1D) via mechanisms that remain largely unknown. The inflammasome components are innate immune sensors that are highly influenced by the gut environment and play pivotal roles in maintaining intestinal immune homeostasis. In this study we show that modifications of the gut microbiota induced by oral treatment with Lactobacillaceae-enriched probiotic VSL#3, alone or in combination with retinoic acid (RA), protect NOD mice from T1D by affecting inflammasome at the intestinal level. In particular, we show that VSL#3 treatment inhibits IL-1β expression while enhancing release of protolerogenic components of the inflammasome, such as indoleamine 2,3-dioxygenase (IDO) and IL-33. Those modifications of the intestinal microenvironment in VSL#3-treated NOD mice modulate gut immunity by promoting differentiation of tolerogenic CD103(+) DCs and reducing differentiation/expansion of Th1 and Th17 cells in the intestinal mucosa and at the sites of autoimmunity, that is, within the pancreatic lymph nodes (PLN) of VSL#3-treated NOD mice. Our data provide a link between dietary factors, microbiota composition, intestinal inflammation, and immune homeostasis in autoimmune diabetes and could pave the way for new therapeutic approaches aimed at changing the intestinal microenvironment with probiotics to counterregulate autoimmunity and prevent T1D.

  1. 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.

  2. Effect of surfactant-induced cell surface modifications on electron transport system and catechol 1,2-dioxygenase activities and phenanthrene biodegradation by Citrobacter sp. SA01.

    Science.gov (United States)

    Li, Feng; Zhu, Lizhong

    2012-11-01

    In order to better understand how surfactants affect biodegradation of hydrophobic organic compounds (HOCs), Tween 80 and sodium dodecyl benzene sulfonate (SDBS), were selected to investigate effects on cell surface hydrophobicity (CSH), electron transport system (ETS) activities and phenanthrene biodegradation by Citrobacter sp. SA01. Tween 80 and SDBS increased CSH by 19.8-25.2%, ETS activities by 352.1-376.0μmol/gmin, catechol 1,2-dioxygenase (C12) activities by 50.8-52.7U/L, and phenanthrene biodegradation by 8.9-17.2% separately in the presence of 50mg/L of surfactants as compared to in their absence. Lipopolysaccharide (LPS) release was 334.7μg/mg in the presence of both surfactants whereas in their absence only 8.6-44.4μg/mg of LPS was released. Thus, enhanced LPS release probably increased ETS and C12 activities as well as phenanthrene biodegradation by increasing CSH. The results demonstrate that surfactant-enhanced CSH provides a simple, yet effective strategy for field applications of surfactant-enhanced bioremediation of HOCs.

  3. 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.

  4. The Fe-heme structure of met-indoleamine 2,3-dioxygenase-2 determined by X-ray absorption fine structure

    Energy Technology Data Exchange (ETDEWEB)

    Aitken, Jade B. [School of Chemistry, The University of Sydney, NSW 2006 (Australia); Australian Synchrotron, Clayton, Victoria 3168 (Australia); Institute of Materials Structure Science, KEK, Tsukuba, Ibaraki 305-0801 (Japan); Austin, Christopher J.D. [School of Chemistry, The University of Sydney, NSW 2006 (Australia); Department of Pathology and Bosch Institute, The University of Sydney, Camperdown, NSW 2006 (Australia); Hunt, Nicholas H.; Ball, Helen J. [Department of Pathology and Bosch Institute, The University of Sydney, Camperdown, NSW 2006 (Australia); Lay, Peter A., E-mail: peter.lay@sydney.edu.au [School of Chemistry, The University of Sydney, NSW 2006 (Australia)

    2014-07-18

    Highlights: • IDO2 is a newly discovered tryptophan metabolising enzyme with a role in immunity. • IDO2’s active site contains a heme moiety for tryptophan binding and catabolism. • EXAFS/XANES analysis provides the first data of an IDO2 Fe-heme environment. • IDO2 Fe-heme exists as a low spin bis(His) form at 10 K; mixed spin-state at RT. - Abstract: Multiple-scattering (MS) analysis of EXAFS data on met-indoleamine 2,3-dioxygenase-2 (IDO2) and analysis of XANES have provided the first direct structural information about the axial donor ligands of the iron center for this recently discovered protein. At 10 K, it exists in a low-spin bis(His) form with Fe–N{sub p}(av) = 1.97 Å, the Fe–N{sub Im} bond lengths of 2.11 Å and 2.05 Å, which is in equilibrium with a high-spin form at room temperature. The bond distances in the low-spin form are consistent with other low-spin hemeproteins, as is the XANES spectrum, which is closer to that of the low-spin met-Lb than that of the high-spin met-Mb. The potential physiological role of this spin equilibrium is discussed.

  5. High-affinity uptake of kynurenine and nitric oxide-mediated inhibition of indoleamine 2,3-dioxygenase in bone marrow-derived myeloid dendritic cells.

    Science.gov (United States)

    Hara, Toshiaki; Ogasawara, Nanako; Akimoto, Hidetoshi; Takikawa, Osamu; Hiramatsu, Rie; Kawabe, Tsutomu; Isobe, Ken-Ichi; Nagase, Fumihiko

    2008-02-15

    Indoleamine 2,3-dioxygenase (IDO)-initiated tryptophan metabolism along the kynurenine (Kyn) pathway in some dendritic cells (DC) such as plasmacytoid DC (pDC) regulates T-cell responses. It is unclear whether bone marrow-derived myeloid DC (BMDC) express functional IDO. The IDO expression was examined in CD11c(+)CD11b(+) BMDC differentiated from mouse bone marrow cells using GM-CSF. CpG oligodeoxynucleotides (CpG) induced the expression of IDO protein with the production of nitric oxide (NO) in BMDC in cultures for 24h. In the enzyme assay using cellular extracts of BMDC, the IDO activity of BMDC stimulated with CpG was enhanced by the addition of a NO synthase (NOS) inhibitor, suggesting that IDO activity was suppressed by NO production. On the other hand, the concentration of Kyn in the culture supernatant of BMDC was not increased by stimulation with CpG. Exogenously added Kyn was taken up by BMDC independently of CpG stimulation and NO production, and the uptake of Kyn was inhibited by a transport system L-specific inhibitor or high concentrations of tryptophan. The uptake of tryptophan by BMDC was markedly lower than that of Kyn. In conclusion, IDO activity in BMDC is down-regulated by NO production, whereas BMDC strongly take up exogenous Kyn.

  6. The Effect of Dietary Glycine on the Hepatic Tumor Promoting Activity of Polychlorinated Biphenyls (PCBs) in Rats

    OpenAIRE

    Bunaciu, Rodica Petruta; Tharappel, Job C.; Lehmler, Hans-Joachim; Korwel, Izabela; Robertson, Larry W.; Srinivasan, Cidambi; Spear, Brett T.; Glauert, Howard P.

    2007-01-01

    Polychlorinated biphenyls (PCBs) are ubiquitious lipophilic environmental pollutants. Some of the PCB congeners and mixtures of congeners have tumor promoting activity in rat liver. The mechanism of their activity is not fully understood and is likely to be multifactorial. The aim of this study was to investigate if the resident liver macrophages, Kupffer cells, are important in the promoting activity of PCBs. The hypothesis of this study was that the inhibition of Kupffer cell activity would...

  7. Activity of alkaline and acidic phosphatase in glandular cells of uterine endometrium of puerperal ewes after exposure to polychlorinated biphenyls

    OpenAIRE

    Valocky I.; Krajničakova Maria; Legath J.; Lenhardt L.; Ostro A.; Danko J.; Tkačikova L`udmila; Mojžišova Jana; Fialkovičova Maria; Mardzinova Silvia

    2005-01-01

    The study is focused on the observation of alkaline and acidic phosphatase activity in the glandular cells of uterine endometrium in puerperal ewes after exposure to polychlorinated biphenyls. Ewes of Slovak merino breed (n=25) divided into 2 groups were included in the experiment. The animals in the experimental group (n=14) and control group (n=11) were euthanised on day 17, 25 and 34 postpartum. The ewes in the experimental group were given per os capsules of the chemical preparation Delor...

  8. Polychlorinated Biphenyls Disturb Differentiation of Normal Human Neural Progenitor Cells: Clue for Involvement of Thyroid Hormone Receptors

    OpenAIRE

    Fritsche, Ellen; Cline, Jason E.; Nguyen, Ngoc-Ha; Scanlan, Thomas S.; Abel, Josef

    2005-01-01

    Polychlorinated biphenyls (PCBs) are ubiquitous environmental chemicals that accumulate in adipose tissues over the food chain. Epidemiologic studies have indicated that PCBs influence brain development. Children who are exposed to PCBs during development suffer from neuropsychologic deficits such as a lower full-scale IQ (intelligence quotient), reduced visual recognition memory, and attention and motor deficits. The mechanisms leading to these effects are not fully understood. It has been s...

  9. Bioactivation of dibrominated biphenyls by cytochrome P450 activity to metabolites with estrogenic activity and estrogen sulfotransferase inhibition capacity.

    Science.gov (United States)

    van Lipzig, Marola M H; Commandeur, Jan N; de Kanter, Frans J J; Damsten, Micaela C; Vermeulen, Nico P E; Maat, Evelina; Groot, Ed J; Brouwer, Abraham; Kester, Monique H A; Visser, Theo J; Meerman, John H N

    2005-11-01

    Exposure of humans and wildlife to xenobiotics, such as halogenated biphenyls, that interfere with the endogenous estrogen balance may lead to endocrine disruption. Such compounds may either mimic or block estradiol's action by agonistic or antagonistic action, respectively. They may also affect endogenous estradiol concentrations by induction or inhibition of enzymes that metabolize estradiol. In the present study, we demonstrate that estrogenic metabolites of two brominated biphenyls, 2,2'-dibromobiphenyl (2,2'-DBB) and 4,4'-dibromobiphenyl (4,4'-DBB), are formed by rat liver microsomal cytochrome P450 (CYP) activity. Bioactivation of 2,2'-DBB and 4,4'-DBB yielded various mono- and dihydroxylated bromobiphenyl metabolites, which were collected by preparative HPLC and analyzed by LC/MS. Several of the metabolites bound to the estrogen receptor (ER) activated the ER and inhibited human estrogen sulfotransferase (hEST). Seven monohydroxylated metabolites were positively identified using synthetic monohydroxylated reference compounds. These synthetic monohydroxylated bromobiphenyls also bound to and activated the ER and inhibited hEST. The highest ER affinity was observed for 4-OH-2,2'-DBB, with an EC50 of 6.6 nM. The highest ER activation was observed for 4-OH-3,4'-DBB (EC50 of 74 nM) while 4-OH-4'-MBB and 4-OH-2,2'-DBB induced a supramaximal (as compared to estradiol) ER activation. The strongest hEST inhibition was found with 4-OH-3,4'-DBB (EC50 = 40 nM). In conclusion, we show that two dibrominated biphenyls are bioactivated by CYP activity into very potent estrogenic metabolites and inhibitors of hEST. These findings are of vital importance for accurate risk assessment of exposure to environmental contaminants, such as halogenated biphenyls. Neglecting bioactivation through biotransformation will lead to underestimation of health risks of this class of xenobiotics.

  10. Rapid Detection of Polychlorinated Biphenyls at Trace Levels in Real Environmental Samples by Surface-Enhanced Raman Scattering

    Directory of Open Access Journals (Sweden)

    Zhengjun Zhang

    2011-11-01

    Full Text Available Detection of trace levels of persistent pollutants in the environment is difficult but significant. Organic pollutant homologues, due to their similar physical and chemical properties, are even more difficult to distinguish, especially in trace amounts. We report here a simple method to detect polychlorinated biphenyls (PCBs in soil and distilled spirit samples by the surface-enhanced Raman scattering technique using Ag nanorod arrays as substrates. By this method, polychlorinated biphenyls can be detected to a concentration of 5 μg/g in dry soil samples within 1 minute. Furthermore, based on simulation and understanding of the Raman characteristics of PCBs, we recognized homologues of tetrachlorobiphenyl by using the surface-enhance Raman scattering method even in trace amounts in acetone solutions, and their characteristic Raman peaks still can be distinguished at a concentration of 10-6 mol/L. This study provides a fast, simple and sensitive method for the detection and recognition of organic pollutants such as polychlorinated biphenyls.

  11. Magnetoelectrochemistry of 4,4'-bis(dimethylamino)biphenyl and 4,4'-dinitrobiphenyl azacrown macrocyclic lactams

    Energy Technology Data Exchange (ETDEWEB)

    Domenech, Antonio [Departament de Quimica Analitica, Universitat de Valencia, Dr. Moliner 50, 46100 Burjassot, Valencia (Spain); Costero, Ana Maria; Banuls, Maria Jose; Aurell, Maria Jose [Departament de Quimica Organica, Universitat de Valencia, Dr. Moliner 50, 46100 Burjassot, Valencia (Spain)

    2005-07-25

    The voltammetric behaviour at carbon fibre microelectrodes under the application of static magnetic fields of two series of macrolactams containing in their structure 4,4'-bis(dimethylamino)biphenyl or 4,4'-dinitrobiphenyl groups in MeCN solution is described. The response of 4,4'-dinitrobiphenyl receptors is dominated by two successive one-electron reduction processes at -0.9 and -1.6 V versus AgCl/Ag. 4,4'-bis(dimethylamino)biphenyl-containing receptors display two one-electron oxidations above +0.8 and +1.0 V. In both cases, a dihedral/planar interconversion precedes the second electron transfer step. Upon application of moderate (0.05-0.2 T) static magnetic fields to the electrochemical cell, the rate of such dihedral/planar interconversion is lowered for both the reduction of 4,4'-dinitrobiphenyl receptors and the oxidation of 4,4'-bis(dimethylamino)biphenyl lactams. The electrochemical response of N-methylated receptors, for which different cisoid-cisoid, cisoid-transoid, and transoid-transoid forms exist, exhibits a significant peak splitting that can be associated to the presence of such conformational isomers. Application of magnetic fields produces a relative enhancement of some peaks that can be interpreted in terms of differential magnetoconvection involving such conformational isomers. (author)

  12. Congener-specific polychlorinated biphenyl patterns in eggs of aquatic birds from the lower Laguna Madre, Texas

    Science.gov (United States)

    Mora, Miguel A.

    1996-01-01

    Eggs from four aquatic bird species nesting in the Lower Laguna Madre, Texas, were collected to determine differences and similarities in the accumulation of congener-specific polychlorinated biphenyls (PCBs) and to evaluate PCB impacts on reproduction. Because of the different toxicities of PCB congeners, it is important to know which congeners contribute most to total PCBs. The predominant PCB congeners were 153, 138, 180, 110, 118, 187, and 92. Collectively, congeners 153, 138, and 180 accounted for 26 to 42% of total PCBs. Congener 153 was the most abundant in Caspian terns (Sterna caspia) and great blue herons (Ardea herodias) and congener 138 was the most abundant in snowy egrets (Egretta thula) and tricolored herons (Egretta tricolor). Principal component analysis indicated a predominance of higher chlorinated biphenyls in Caspian terns and great blue herons and lower chlorinated biphenyls in tricolored herons. Snowy egrets had a predominance of pentachlorobiphenyls. These results suggest that there are differences in PCB congener patterns in closely related species and that these differences are more likely associated with the species' diet rather than metabolism. Total PCBs were significantly greater (p Laguna Madre were below concentrations known to affect bird reproduction.

  13. Congener-specific polychlorinated biphenyl patterns in eggs of aquatic birds from the Lower Laguna Madre, Texas

    Energy Technology Data Exchange (ETDEWEB)

    Mora, M.A. [Texas A and M Univ., College Station, TX (United States)

    1996-06-01

    Eggs from four aquatic bird species nesting in the Lower Laguna Madre, Texas, were collected to determine differences and similarities in the accumulation of congener-specific polychlorinated biphenyls (PCBs) and to evaluate PCB impacts on reproduction. Because of the different toxicities of PCB congeners, it is important to know which congeners contribute most to total PCBs. The predominant PCB congeners were 153, 138, 180, 110, 118, 187, and 92. Collectively, congeners 153, 138, and 180 accounted for 26 to 42% of total PCBs. Congener 153 was the most abundant in Caspian terns (Sterna caspia) and great blue herons (Ardea herodias) and congener 138 was the most abundant in snowy egrets (Egretta thula) and tricolored herons (Egretta tricolor). Principal component analysis indicated a predominance of higher chlorinated biphenyls in Caspian terns and great blue herons and lower chlorinated biphenyls in tricolored herons. Snowy egrets had a predominance of pentachlorobiphenyls. These results suggest that there are differences in PCB congener patterns in closely related species and that these differences are more likely associated with the species` diet rather than metabolism. Total PCBs were significantly greater (p < 0.05) in Caspian terns than in the other species. Overall, PCBs in eggs of birds from the Lower Laguna Madre were below concentrations known to affect bird reproduction.

  14. Identification of a novel dimethoxylated polybrominated biphenyl bioaccumulating in marine mammals

    Energy Technology Data Exchange (ETDEWEB)

    Marsh, G.; Athanasiadou, M.; Bergman, Aa.; Athanassiadis, I. [Department of Environmental Chemistry, Stockholm (Sweden); Endo, Tetsuya [Health Sciences Univ. of Hokkaido (Japan). Fac. of Pharmaceutical Sciences; Haraguchi, Koichi [Daiichi College of Pharmaceutical Sciences, Fukuoka (Japan)

    2004-09-15

    The screening of persistent halogenated organic pollutants has in recent years ended up with findings of numerous compounds being natural products. These compounds have preferably been reported from the marine environment and comprise, several hydroxylated and methoxylated polybrominated diphenyl ethers (OH-PBDEs and MeO-PBDEs) including monochlorinated ditto, a dimethoxylated polybrominated diphenyl ether i.e. 2',6-dimethoxy-2,3',4,5'-tetrabromodiphenyl ether, four halogenated dimethylated bipyrroles (HDBPs) with a 2,2'-bipyrrole backbone, a heptachlorinated 1,2'-bipyrrole i.e. heptachloro-1'-methyl-1,2'-bipyrrole (Q1)6 and a halogenated monoterpene holding two bromine and three chlorine atoms. We have taken interest in an organobrominated compound with an unknown structure but with a molecule ion of m/z = 526 and a four bromine isotope pattern according to mass spectrometry (MS), detected in marine mammal samples of which the majority were collected from Japanese coastal waters. This compound has recently been reported from several marine mammals collected on the Southern hemisphere, but neither the chemical structure nor the type of substance group were established. We here report the structure of this organobrominated compound, a dimethoxylated polybrominated biphenyl, which likely is of natural origin. The identification was done by the comparison of relative retention time (RRT) on two GC columns with different polarities and by comparing mass spectra from three different ionization techniques i.e. PICI, ECNI and EI, of the unknown compound from the samples with an authentic reference compound. Levels of the novel dimethoxylated polybrominated biphenyl are reported as well as the levels (for comparison) of some other known polybrominated compounds, both brominated flame retardants (BFRs) and natural products i.e. BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, BDE-183, 1,2,5,6,9,10- hexabromocyclododecane (HBCDD), 6-MeO-BDE-47, 2

  15. Isolation and characterisation of polychlorinated biphenyl (PCB degrading fungi from a historically contaminated soil

    Directory of Open Access Journals (Sweden)

    Di Toro Sara

    2009-01-01

    Full Text Available Abstract Background Polychlorinated biphenyls (PCBs are widespread toxic pollutants. Bioremediation might be an effective, cost competitive and environment-friendly solution for remediating environmental matrices contaminated by PCBs but it is still unsatisfactory, mostly for the limited biodegradation potential of bacteria involved in the processes. Very little is known about mitosporic fungi potential in PCB bioremediation and their occurrence in actual site historically contaminated soils. In the present study, we characterised the native mycoflora of an aged dump site soil contaminated by about 0.9 g kg-1 of Aroclor 1260 PCBs and its changing after aerobic biotreatment with a commercial complex source of bacteria and fungi. Fungi isolated from the soil resulting from 120 days of treatment were screened for their ability to adsorb or metabolise 3 target PCBs. Results The original contaminated soil contained low loads of few fungal species mostly belonging to the Scedosporium, Penicillium and Aspergillus genera. The fungal load and biodiversity generally decreased throughout the aerobic treatment. None of the 21 strains isolated from the treated soil were able to grow on biphenyl (200 mg L-1 or a mixture of 2-chlorobiphenyl, 4,4'-dichlorobiphenyl and 2,2',5,5'-tetrachlorobiphenyl (20 mg L-1 each as sole carbon sources. However, 16 of them grew in a mineral medium containing the same PCBs mixture and glucose (10 g L-1. Five of the 6 isolates, which displayed the faster and more extensive growth under the latter conditions, were found to degrade the 3 PCBs apparently without the involvement of ligninolytic enzymes; they were identified as Penicillium chrysogenum, Scedosporium apiospermum, Penicillium digitatum and Fusarium solani. They are the first PCB degrading strains of such species reported so far in the literature. Conclusion The native mycoflora of the actual site aged heavily contaminated soil was mainly constituted by genera often

  16. Association between dietary intake of polychlorinated biphenyls and the incidence of hypertension in a Spanish cohort: the Seguimiento Universidad de Navarra project.

    Science.gov (United States)

    Donat-Vargas, Carolina; Gea, Alfredo; Sayon-Orea, Carmen; de la Fuente-Arrillaga, Carmen; Martinez-Gonzalez, Miguel Angel; Bes-Rastrollo, Maira

    2015-04-01

    Polychlorinated biphenyls are persistent organic pollutants that are consumed because of their bioaccumulation through the food chain. Evidence from different sources suggests a positive association between polychlorinated biphenyls exposure and the incidence of hypertension. However, no previous prospective study has investigated this potential relationship in adults. We prospectively assessed the association between dietary intake of polychlorinated biphenyls and the incidence of hypertension in a large cohort. The Seguimiento Universidad de Navarra project is a Spanish cohort of university graduates, most of them health professionals. We included 14521 participants, initially free of hypertension, who were followed-up for a median of 8.3 years. Dietary intake of polychlorinated biphenyls was assessed at baseline through a previously validated 136-item semiquantitative food frequency questionnaire. The published concentration levels of polychlorinated biphenyls measured in samples of food consumed in Spain were used to estimate dietary intake. Multivariable Cox regression models were fitted to estimate hazard ratios and 95% confidence interval for incident hypertension. During follow-up, 1497 incident cases of medically diagnosed hypertension were identified. After adjusting for total energy intake and for potential confounders, participants in the fifth quintile of total polychlorinated biphenyls intake were at higher risk of developing hypertension (adjusted hazard ratio, 1.43 [95% confidence interval, 1.09-1.88; P for trend 0.017]) compared with those in the first quintile. In this Mediterranean cohort, dietary intake of polychlorinated biphenyls, estimated using a food frequency questionnaire, was associated with a higher risk of developing hypertension during follow-up. Nevertheless, further longitudinal studies are needed to confirm our results.

  17. Polychlorinated biphenyl (PCB) and dioxin concentrations in residential dust of pregnant women.

    Science.gov (United States)

    Hinwood, A L; Callan, A C; Heyworth, J; Rogic, D; de Araujo, J; Crough, R; Mamahit, G; Piro, N; Yates, A; Stevenson, G; Odland, J Ø

    2014-12-01

    Polychlorinated biphenyls (PCBs) and dioxins are well known for their persistence in the environment. PCBs can be found in the residential environment long after the use of these chemicals in domestic products and industrial processes has ceased. Dioxins have been assessed in Australia as being of very low concentrations. Despite concerns about residential dust as a source of human exposure to persistent chemicals, there has been limited testing of PCBs and dioxins in dust in Australia. As part of an assessment of maternal exposure to a variety of persistent toxic substances, we analysed 30 residential dust samples from a variety of geographical settings for their dioxin and PCB concentrations. PCBs were found in most samples, the median and range concentrations (pg g(-1)) of dominant congeners of PCB were as follows: PCB118 (315; PCB105 (130; 14.0-16 000) and PCB156 (440; PCB congener concentrations and dioxin isomers in multivariate regression analyses. No other housing or sociodemographic variables, including proximity to industry, were important predictors in multivariate linear regression models.

  18. Geminate recombination kinetics of solute radical ions. Singlet excited state formation in cyclohexane solutions of biphenyl

    Science.gov (United States)

    Tagawa, S.; Washio, M.; Tabata, Y.; Kobayashi, H.

    Transient absorption spectra of the solute anion, cation and triplet state and the solute fluorescence in the pulse radiolysis of 0.1 mole 1 -1 biphenyl in cyclohexane were observed on a nanosecond timescale longer than 1 ns after a 20 ps pulse. The formation of the solute excited singlet state is mainly due to the geminate ion recombination reaction even in the high concentrated solutions. The decay of the solute ions obeys the reciprocal square root dependence on time longer than 10 ns from the end of a 10 ps pulse. The slope of this reciprocal square root plots agrees with the literature value on a longer timescale obtained by microwave absorption. The yield of free ions obtained from the intercept of the slope agrees also with the literature values obtained by the field clearing method. Ratio of the formation rate of the solute excited triplet state to the decay rate of the solute anion changes in a time range between 5 and 20 ns. It is very well correlated with a theoretical calculation of spin correlation decay of the germinate ion pairs by Brocklehurst, although the formation of the solute triplet state was observed even on a timescale shorter than 5 ns from the end of a 20 ps pulse, where loss of spin correlation is negligibly small.

  19. Persistent or not persistent? Polychlorinated biphenyls are readily depurated by grizzly bears (Ursus arctos horribilis).

    Science.gov (United States)

    Christensen, Jennie R; Letcher, Robert J; Ross, Peter S

    2009-10-01

    Major pharmacokinetic processes influencing polychlorinated biphenyl (PCB) accumulation in mammals include uptake, biotransformation, respiration, and excretion. We characterized some of the factors underlying PCB accumulation/loss by evaluating PCB concentrations and patterns in pre- and posthibernation grizzly bears (Ursus arctos horribilis) and their prey. The PCB congeners with vicinal meta- and para-chlorine unsubstituted hydrogen positions consistently showed loss both before and during hibernation, supporting the idea of a dominant role for biotransformation. Retention of all other studied congeners relative to that of PCB 194 varied widely (from bears do not eat or excrete. We estimate that grizzly bears retain less than 10% of total PCBs taken up from their diet. Our results suggest that for grizzly bears, depuration of PCBs via biotransformation is important (explaining approximately 40% of loss), but that nonbiotransformation processes, such as excretion, may be more important (explaining approximately 60% of loss). These findings, together with the approximately 91% loss of the persistent PCB 153 congener relative to PCB 194 in grizzly bears, raise important questions about how one defines persistence of PCBs in wildlife and may have bearing on the interpretation of food-web biomagnification studies.

  20. Modeling the depuration rates of polychlorinated biphenyls in two mussel species with theoretical molecular descriptors

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Using theoretical molecular descriptors as well as partial least squares(PLS) regression,two quantitative structure-activity relationship(QSAR) models were developed for depuration rate constants(kd) of polychlorinated biphenyls(PCBs) in two species of mussels,Perna viridis and Dreissena polymorpha.The cross-validated Q2cum(an indicator of fitting of goodness) values for the two models are 0.501 and 0.756,and the standard deviation(SD) is 0.084 and 0.076,respectively.The achievement of satisfactory Q2cum and low SD values indicates good predictive ability and precision of the two models.The significant descriptors governing lgkd include polarizability(α),molecular volume(MV),molecular weight(Mw),molecular surface area(S),and total energy(TE).The key descriptors in the models reflect that van der Waals interactions play a dominant role in the depuration of PCBs.The depuration of PCBs in the two mussel species may be mainly attributed to the biota-water phase partitioning processes.