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Sample records for biphenyl degradation pathway

  1. Metabolic Pathways of Polychlorinated Biphenyls Degradation by Pseudomonas sp. 2

    Czech Academy of Sciences Publication Activity Database

    Komancová, M.; Jurčová, Irena; Kochánková, L.; Burkhard, J.

    2003-01-01

    Roč. 50, č. 4 (2003), s. 537ů543 ISSN 0045-6535 Institutional research plan: CEZ:AV0Z4072921 Keywords : polychlorinated biphenyls * biodegradation * aerobic bacteria Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.904, year: 2003

  2. 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...

  3. Biotransformation and reduction of estrogenicity of bisphenol A by the biphenyl-degrading Cupriavidus basilensis.

    Science.gov (United States)

    Zühlke, Marie-Katherin; Schlüter, Rabea; Mikolasch, Annett; Zühlke, Daniela; Giersberg, Martin; Schindler, Henning; Henning, Ann-Kristin; Frenzel, Heidi; Hammer, Elke; Lalk, Michael; Bornscheuer, Uwe T; Riedel, Katharina; Kunze, Gotthard; Schauer, Frieder

    2017-05-01

    The biphenyl-degrading Gram-negative bacterium Cupriavidus basilensis (formerly Ralstonia sp.) SBUG 290 uses various aromatic compounds as carbon and energy sources and has a high capacity to transform bisphenol A (BPA), which is a hormonally active substance structurally related to biphenyl. Biphenyl-grown cells initially hydroxylated BPA and converted it to four additional products by using three different transformation pathways: (a) formation of multiple hydroxylated BPA, (b) ring fission, and (c) transamination followed by acetylation or dimerization. Products of the ring fission pathway were non-toxic and all five products exhibited a significantly reduced estrogenic activity compared to BPA. Cell cultivation with phenol and especially in nutrient broth (NB) resulted in a reduced biotransformation rate and lower product quantities, and NB-grown cells did not produce all five products in detectable amounts. Thus, the question arose whether enzymes of the biphenyl degradation pathway are involved in the transformation of BPA and was addressed by proteomic analyses.

  4. 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

  5. Construction of a rhizosphere pseudomonad with potential to degrade polychlorinated biphenyls and detection of bph gene expression in the rhizosphere.

    OpenAIRE

    Brazil, G M; Kenefick, L; Callanan, M; Haro, A; de Lorenzo, V; Dowling, D N; O'Gara, F

    1995-01-01

    The genetically engineered transposon TnPCB, contains genes (bph) encoding the biphenyl degradative pathway. TnPCB was stably inserted into the chromosome of two different rhizosphere pseudomonads. One genetically modified strain, Pseudomonas fluorescens F113pcb, was characterized in detail and found to be unaltered in important parameters such as growth rate and production of secondary metabolites. The expression of the heterologous bph genes in F113pcb was confirmed by the ability of the ge...

  6. Microcosm enrichment of biphenyl-degrading microbial communities from soils and sediments

    Energy Technology Data Exchange (ETDEWEB)

    Wagner-Doebler, I.; Bennasar, A.; Stroempl, C.; Bruemmer, I.; Eichner, C.; Grammel, I.; Moore, E.R.B. [GBF National Research Inst. for Biotechnology, Braunschweig (Germany). Dept. of Microbiology; Vancanneyt, M. [Univ. Gent, Ghent (Belgium). Lab. voor Microbiologie

    1998-08-01

    A microcosm enrichment approach was employed to isolate bacteria which are representative of long-term biphenyl-adapted microbial communities. Growth of microorganisms was stimulated by incubating soil and sediment samples from polluted and nonpolluted sites with biphenyl crystals. After 6 months, stable population densities between 8 {times} 10{sup 9} and 2 {times} 10{sup 11} CFU/ml were established in the microcosms, and a large percentage of the organisms were able to grow on biphenyl-containing minimal medium plates. A total of 177 biphenyl-degrading strains were subsequently isolated and characterized by their ability to grow on biphenyl in liquid culture and to accumulate a yellow meta cleavage product when they were sprayed with dihydroxy-biphenyl. Isolates were identified by using a polyphasic approach, including fatty acid methyl ester (FAME) analysis, 16S rRNA gene sequence comparison, sodium dodecyl sulfate-polyacrylamide gel electrophoresis of whole-cell proteins, and genomic fingerprinting based on sequence variability in the 16S-23S ribosomal DNA intergenic spacer region. In all of the microcosms, isolates identified as Rhodococcus opacus dominated the cultivable microbial community, comprising a cluster of 137 isolates with very similar FAME profiles (Euclidean distances, <10) and identical 16S rRNA gene sequences.

  7. Microcosm enrichment of biphenyl-degrading microbial communities from soils and sediments.

    Science.gov (United States)

    Wagner-Döbler, I; Bennasar, A; Vancanneyt, M; Strömpl, C; Brümmer, I; Eichner, C; Grammel, I; Moore, E R

    1998-08-01

    A microcosm enrichment approach was employed to isolate bacteria which are representative of long-term biphenyl-adapted microbial communities. Growth of microorganisms was stimulated by incubating soil and sediment samples from polluted and nonpolluted sites with biphenyl crystals. After 6 months, stable population densities between 8 x 10(9) and 2 x 10(11) CFU/ml were established in the microcosms, and a large percentage of the organisms were able to grow on biphenyl-containing minimal medium plates. A total of 177 biphenyl-degrading strains were subsequently isolated and characterized by their ability to grow on biphenyl in liquid culture and to accumulate a yellow meta cleavage product when they were sprayed with dihydroxybiphenyl. Isolates were identified by using a polyphasic approach, including fatty acid methyl ester (FAME) analysis, 16S rRNA gene sequence comparison, sodium dodecyl sulfate-polyacrylamide gel electrophoresis of whole-cell proteins, and genomic fingerprinting based on sequence variability in the 16S-23S ribosomal DNA intergenic spacer region. In all of the microcosms, isolates identified as Rhodococcus opacus dominated the cultivable microbial community, comprising a cluster of 137 isolates with very similar FAME profiles (Euclidean distances, <10) and identical 16S rRNA gene sequences. The R. opacus isolates from the different microcosms studied could not be distinguished from each other by any of the fingerprint methods used. In addition, three other FAME clusters were found in one or two of the microcosms analyzed; these clusters could be assigned to Alcaligenes sp., Terrabacter sp., and Bacillus thuringiensis on the basis of their FAME profiles and/or comparisons of the 16S rRNA gene sequences of representatives. Thus, the microcosm enrichments were strongly dominated by gram-positive bacteria, especially the species R. opacus, independent of the pollution history of the original sample. R. opacus, therefore, is a promising candidate for

  8. Rhodococcus biphenylivorans sp. nov., a polychlorinated biphenyl-degrading bacterium.

    Science.gov (United States)

    Su, Xiaomei; Liu, Yindong; Hashmi, Muhammad Zaffar; Hu, Jinxing; Ding, Linxian; Wu, Min; Shen, Chaofeng

    2015-01-01

    A Gram-positive, aerobic, non-motile and rod-coccus shaped novel actinobacterial strain, designated as TG9(T), was isolated from a polychlorinated biphenyl (PCB)-contaminated sediment in Taizhou city, Zhejiang province, eastern China. The isolate was observed to grow at 10-45 °C (optimum 28-32 °C), pH 5.0-11.0 (optimum pH 7.0-8.0) and with 0-9.0 % (w/v) NaCl (optimum 0-3.0 %). Comparison of the 16S rRNA gene sequences of strain TG9(T) and other members of the genus Rhodococcus showed that strain TG9(T) shared highest similarities with Rhodococcus pyridinivorans DSM 44555(T) (99.4 %), R. rhodochrous DSM 43241(T) (99.2 %), R. gordoniae DSM 44689(T) (99.2 %) and R. artemisiae DSM 45380(T) (98.2 %). However, low levels of DNA-DNA relatedness (15-48 %), which are below the 70 % limit for prokaryotic species identification, were obtained by DNA-DNA hybridization. Strain TG9(T) was found to contain meso-diaminopimelic acid as the diagnostic diamino acid and arabinose and galactose in the whole-cell hydrolysate. Mycolic acids were found to be present. The major fatty acids were identified as C16:0, C16:1 ω7c and/or iso-C15:0 2-OH, 10-methyl C18:0 and C18:1 ω9c. The only menaquinone detected was MK-8 (H2). The major polar lipids detected were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, glycolipid and traces of some unknown lipids. The genomic DNA G+C content of strain TG9(T) was determined to be 62.8 %. The combined phenotypic and genotypic data show that the strain represents a novel species of the genus Rhodococcus for which the name Rhodococcus biphenylivorans sp. nov. is proposed, with the type strain TG9(T) (=CGMCC 1.12975(T) = KCTC 29673(T) = MCCC 1K00286(T)).

  9. 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. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Construction of a rhizosphere pseudomonad with potential to degrade polychlorinated biphenyls and detection of bph gene expression in the rhizosphere.

    Science.gov (United States)

    Brazil, G M; Kenefick, L; Callanan, M; Haro, A; de Lorenzo, V; Dowling, D N; O'Gara, F

    1995-05-01

    The genetically engineered transposon TnPCB, contains genes (bph) encoding the biphenyl degradative pathway. TnPCB was stably inserted into the chromosome of two different rhizosphere pseudomonads. One genetically modified strain, Pseudomonas fluorescens F113pcb, was characterized in detail and found to be unaltered in important parameters such as growth rate and production of secondary metabolites. The expression of the heterologous bph genes in F113pcb was confirmed by the ability of the genetically modified microorganism to utilize biphenyl as a sole carbon source. The introduced trait remained stable in laboratory experiments, and no bph-negative isolates were found after extensive subculture in nonselective media. The bph trait was also stable in nonselective rhizosphere microcosms. Rhizosphere competence of the modified F113pcb was assessed in colonization experiments in nonsterile soil microcosms on sugar beet seedling roots. F113pcb was able to colonize as efficiently as a marked wild-type strain, and no decrease in competitiveness was observed. In situ expression of the bph genes in F113pcb was found when F113pcb bearing a bph'lacZ reporter fusion was inoculated onto sugar beet seeds. This indicates that the bph gene products may also be present under in situ conditions. These experiments demonstrated that rhizosphere-adapted microbes can be genetically manipulated to metabolize novel compounds without affecting their ecological competence. Expression of the introduced genes can be detected in the rhizosphere, indicating considerable potential for the manipulation of the rhizosphere as a self-sustaining biofilm for the bioremediation of pollutants in soil. Rhizosphere bacteria such as fluorescent Pseudomonas spp. are ecologically adapted to colonize and compete in the rhizosphere environment. Expanding the metabolic functions of such pseudomonads to degrade pollutants may prove to be a useful strategy for bioremediation.

  11. Photocatalytic degradation of geosmin: Reaction pathway analysis ...

    African Journals Online (AJOL)

    The presence of geosmin in drinking water imparts a musty odour which leads to consumer complaints. Geosmin and other unwanted organics can be treated using photocatalysis. However, the intermediates formed during the photocatalytic degradation process and their degradation pathways have not previously been ...

  12. 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

  13. Photocatalytic degradation of geosmin: Reaction pathway analysis

    African Journals Online (AJOL)

    2011-07-25

    Jul 25, 2011 ... The presence of geosmin in drinking water imparts a musty odour which leads to consumer complaints. Geosmin and other unwanted organics can be treated using photocatalysis. However, the intermediates formed during the photocatalytic degra- dation process and their degradation pathways have not ...

  14. 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.

  15. 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). Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Preparation of plants containing bacterial enzyme for degradation of polychlorinated biphenyls

    Czech Academy of Sciences Publication Activity Database

    Francová, K.; Surá, M.; Macek, Tomáš; Szekeres, M.; Bancos, S.; Demnerová, K.; Sylvestre, M.; Macková, M.

    2003-01-01

    Roč. 12, č. 3 (2003), s. 309-313 ISSN 1018-4619 Institutional research plan: CEZ:AV0Z4055905 Keywords : transgenic plants * polychlorinated biphenyls * phytoremediation Subject RIV: DK - Soil Contamination ; De-contamination incl. Pesticides Impact factor: 0.325, year: 2003

  17. BACE is degraded via the lysosomal pathway.

    Science.gov (United States)

    Koh, Young Ho; von Arnim, Christine A F; Hyman, Bradley T; Tanzi, Rudolph E; Tesco, Giuseppina

    2005-09-16

    Amyloid plaques are formed by aggregates of amyloid-beta-peptide, a 37-43-amino acid fragment (primarily Abeta(40) and Abeta(42)) generated by proteolytic processing of the amyloid precursor protein (APP) by beta- and gamma-secretases. A type I transmembrane aspartyl protease, BACE (beta-site APP cleaving enzyme), has been identified to be the beta-secretase. BACE is targeted through the secretory pathway to the plasma membrane where it can be internalized to endosomes. The carboxyl terminus of BACE contains a di-leucine-based signal for sorting of transmembrane proteins to endosomes and lysosomes. In this study, we set out to determine whether BACE is degraded by the lysosomal pathway and whether the di-leucine motif is necessary for targeting BACE to the lysosomes. Here we show that lysosomal inhibitors, chloroquine and NH(4)Cl, lead to accumulation of endogenous and ectopically expressed BACE in a variety of cell types, including primary neurons. Furthermore, the inhibition of lysosomal hydrolases results in the redistribution and accumulation of BACE in the late endosomal/lysosomal compartments (lysosome-associated membrane protein 2 (LAMP2)-positive). In contrast, the BACE-LL/AA mutant, in which Leu(499) and Leu(500) in the COOH-terminal sequence (DDISLLK) were replaced by alanines, only partially co-localized with LAMP2-positive compartments following inhibition of lysosomal hydrolases. Collectively, our data indicate that BACE is transported to the late endosomal/lysosomal compartments where it is degraded via the lysosomal pathway and that the di-leucine motif plays a role in sorting BACE to lysosomes.

  18. Degradation of polychlorinated biphenyls in the rhizosphere of rape, Brassica napus L.

    Science.gov (United States)

    Javorská, Hana; Tlustos, Pavel; Kaliszová, Regina

    2009-06-01

    The objective of this study was to investigate the rhizosphere effect of rape plants on polychlorinated biphenyls (PCB) dissipation in soils spiked with seven indicator congeners. Depletion of PCB in the rhizosphere was significantly higher in the soil with lower organic matter content. While in the Chernozem soil, 87% of PCB related to bulk soil were found in the 1st mm from roots, only 62%-69% were found in the Fluvisol soil with no significant influence of increased initial PCB concentration. Further from the roots, the concentration of lower chlorinated congeners decreased, which indicates their greater biodegradation in comparison with more chlorinated ones.

  19. Regulating the 20S Proteasome Ubiquitin-Independent Degradation Pathway

    Directory of Open Access Journals (Sweden)

    Gili Ben-Nissan

    2014-09-01

    Full Text Available For many years, the ubiquitin-26S proteasome degradation pathway was considered the primary route for proteasomal degradation. However, it is now becoming clear that proteins can also be targeted for degradation by the core 20S proteasome itself. Degradation by the 20S proteasome does not require ubiquitin tagging or the presence of the 19S regulatory particle; rather, it relies on the inherent structural disorder of the protein being degraded. Thus, proteins that contain unstructured regions due to oxidation, mutation, or aging, as well as naturally, intrinsically unfolded proteins, are susceptible to 20S degradation. Unlike the extensive knowledge acquired over the years concerning degradation by the 26S proteasome, relatively little is known about the means by which 20S-mediated proteolysis is controlled. Here, we describe our current understanding of the regulatory mechanisms that coordinate 20S proteasome-mediated degradation, and highlight the gaps in knowledge that remain to be bridged.

  20. Understanding Degradation Pathways in Organic Photovoltaics (Poster)

    Energy Technology Data Exchange (ETDEWEB)

    Lloyd, M. T.; Olson, D. C.; Garcia, A.; Kauvar, I.; Kopidakis, N.; Reese, M. O.; Berry, J. J.; Ginley, D. S.

    2011-02-01

    Organic Photovoltaics (OPVs) recently attained power conversion efficiencies that are of interest for commercial production. Consequently, one of the most important unsolved issues facing a new industry is understanding what governs lifetime in organic devices and discovering solutions to mitigate degradation mechanisms. Historically, the active organic components are considered vulnerable to photo-oxidation and represent the primary degradation channel. However, we present several (shelf life and light soaking) studies pointing the relative stability of the active layers and instabilities in commonly used electrode materials. We show that engineering of the hole/electron layer at the electrode can lead to environmentally stable devices even without encapsulation.

  1. Polychlorinated biphenyls (PCBs, hexabromocyclododecanes (HBCDDs and degradation products in topsoil from Australia and the United Kingdom

    Directory of Open Access Journals (Sweden)

    Jennifer Desborough

    2016-03-01

    Full Text Available Hexabromocyclododecane (HBCDD is listed under the Stockholm Convention on persistent organic pollutants, yet very few data are available on HBCDD concentrations in soil. Median concentrations of total hexabromocyclododecanes (ΣHBCDDs from soils from the UK (n = 24 were 0.73 ng g−1 dry weight (range  0.05 from those of HBCDDs; thereby underlining the extent to which HBCDDs have migrated into the UK environment. Moreover, PCB concentrations in this study are not markedly lower than those recorded in UK soils sampled in the mid-1980s indicating that the initial rapid decline in UK contamination with PCBs following bans on their manufacture and use, has not been maintained. Degradation products of HBCDD: pentabromocyclododecenes (PBCDs and tetrabromocyclododecadienes (TBCDs were detected in some UK soil samples with semi-quantitative concentrations ranging between 0.01 and 7.3 ng g−1 for ΣPBCDs and 0.01–1.3 ng g−1 for ΣTBCDs. In Australian soils only ΣTBCDs were detected at concentrations ranging from 0.0023 to 0.45 ng g−1. Chiral signatures of HBCDDs were racemic or non-racemic in all samples indicating minimal edaphic enantioselective degradation. A horizontal transect at the most contaminated UK location (a suburban garden revealed a marked decrease in concentrations of HBCDDs with increasing distance from buildings.

  2. Enzymatic description of the anhydrofructose pathway of glycogen degradation. I

    DEFF Research Database (Denmark)

    Yu, Shukun; Refdahl, Charlotte; Lundt, Inge

    2004-01-01

    The anhydrofructose pathway describes the degradation of glycogen and starch to metabolites via 1,5-anhydro-D-fructose (1,5AnFru). The enzyme catalyzing the first reaction step of this pathway, i.e., a-1,4-glucan lyase (EC 4.2.1.13), has been purified, cloned and characterized from fungi and red...... possessed all enzymes needed for conversion of glycogen to APP, an a-1,4-glucan lyase from this fungus was isolated and partially sequenced. Based on this work, a scheme of the enzymatic description of the anhydrofructose pathway in A. melaloma was proposed. Keywords: Anhydrofructose pathway; Anthracobia...

  3. Biominerlization and possible endosulfan degradation pathway adapted by Aspergillus niger.

    Science.gov (United States)

    Bhalerao, Tejomyee S

    2013-11-28

    Endosulfan is a chlorinated pesticide; its persistence in the environment and toxic effects on biota are demanding its removal. This study aims at improving the tolerance of the previously isolated fungus Aspergillus niger (A. niger) ARIFCC 1053 to endosulfan. Released chloride, dehalogenase activity, and released proteins were estimated along with analysis of endosulfan degradation and pathway identification. The culture could tolerate 1,000 mg/ml of technical grade endosulfan. Complete disappearance of endosulfan was seen after 168 h of incubation. The degradation study could easily be correlated with increase in released chlorides, dehalogenase activity and protein released. Comparative infrared spectral analysis suggested that the molecule of endosulfan was degraded efficiently by A. niger ARIFCC 1053. Obtained mass ion values by GC-MS suggested a hypothetical pathway during endosulfan degradation by A. niger ARIFCC 1053. All these results provide a basis for the development of bioremediation strategies to remediate the pollutant under study in the environment.

  4. New Pathway for Nonphosphorylated Degradation of Gluconate by Aspergillus niger

    Science.gov (United States)

    Elzainy, T. A.; Hassan, M. M.; Allam, A. M.

    1973-01-01

    A new nonphosphorylative pathway for gluconate degradation was found in extracts of a strain of Aspergillus niger. The findings indicate that gluconate is dehydrated into 2-keto-3-deoxy-gluconate (KDG), which then is cleaved into glyceraldehyde and pyruvate. 6-Phosphogluconate was not degraded under the same conditions. In addition, KDG was formed from glyceraldehyde and pyruvate. Very weak activity was obtained when glyceraldehyde 3-phosphate replaced glyceraldehyde in this reaction. PMID:4698214

  5. ORGANOPHOSPHATE PESTICIDE DEGRADATION PATHWAYS DURING DRINKING WATER TREATMENT

    Science.gov (United States)

    Free chlorine has been found to react with organophosphate (OP) pesticides resulting in the more toxic oxon products. We will discuss OP pesticide degradation pathways and modeling in the presence of chlorine and chloramines, as well as present a relationship between structure a...

  6. Kynurenine pathway in psychosis: evidence of increased tryptophan degradation.

    LENUS (Irish Health Repository)

    Barry, Sandra

    2009-05-01

    The kynurenine pathway of tryptophan degradation may serve to integrate disparate abnormalities heretofore identified in research aiming to elucidate the complex aetiopathogenesis of psychotic disorders. Post-mortem brain tissue studies have reported elevated kynurenine and kynurenic acid in the frontal cortex and upregulation of the first step of the pathway in the anterior cingulate cortex of individuals with schizophrenia. In this study, we examined kynurenine pathway activity by measuring tryptophan breakdown, a number of pathway metabolites and interferon gamma (IFN-gamma), which is the preferential activator of the first-step enzyme, indoleamine dioxygenase (IDO), in the plasma of patients with major psychotic disorder. Plasma tryptophan, kynurenine pathway metabolites were measured using high-performance liquid chromatography (HPLC) in 34 patients with a diagnosis on the psychotic spectrum (schizophrenia or schizoaffective disorder) and in 36 healthy control subjects. IFN-gamma was measured using enzyme-linked immunosorbent assay (ELISA). The mean tryptophan breakdown index (kynurenine\\/tryptophan) was significantly higher in the patient group compared with controls (P < 0.05). IFN-gamma measures did not differ between groups (P = 0.23). No relationship was found between measures of psychopathology, symptom severity and activity in the first step in the pathway. A modest correlation was established between the tryptophan breakdown index and illness duration. These results provide evidence for kynurenine pathway upregulation, specifically involving the first enzymatic step, in patients with major psychotic disorder. Increased tryptophan degradation in psychoses may have potential consequences for the treatment of these disorders by informing the development of novel therapeutic compounds.

  7. E1AF degradation by a ubiquitin-proteasome pathway

    International Nuclear Information System (INIS)

    Takahashi, Akiko; Higashino, Fumihiro; Aoyagi, Mariko; Yoshida, Koichi; Itoh, Miyuki; Kobayashi, Masanobu; Totsuka, Yasunori; Kohgo, Takao; Shindoh, Masanobu

    2005-01-01

    E1AF is a member of the ETS family of transcription factors. In mammary tumors, overexpression of E1AF is associated with tumorigenesis, but E1AF protein has hardly been detected and its degradation mechanism is not yet clear. Here we show that E1AF protein is stabilized by treatment with the 26S protease inhibitor MG132. We found that E1AF was modified by ubiquitin through the C-terminal region and ubiquitinated E1AF aggregated in nuclear dots, and that the inhibition of proteasome-activated transcription from E1AF target promoters. These results suggest that E1AF is degraded via the ubiquitin-proteasome pathway, which has some effect on E1AF function

  8. Efficient degradation of tetrabromobisphenol A via electrochemical sequential reduction-oxidation: Degradation efficiency, intermediates, and pathway.

    Science.gov (United States)

    Hou, Yanping; Peng, Zhenbo; Wang, Li; Yu, Zebin; Huang, Lirong; Sun, Lingfang; Huang, Jun

    2018-02-05

    Tetrabromobisphenol A (TBBPA), a toxic persistent pollutant, should be effectively removed from the environment. In this study, an electrochemical sequential reduction-oxidation system was proposed by controlling reaction atmosphere with Pd-Fe nanoparticles modified Ni foam (Pd-Fe/Ni) electrode as cathode for TBBPA degradation. To obtain an efficient Pd-Fe/Ni electrode for TBBPA degradation, various factors, like Pd loading, Fe 2+ adding amounts, were examined. The Pd-Fe/Ni electrode exhibited higher TBBPA conversion and debromination than the counterparts, due to the synergism of Fe 0 and electrochemical reduction. Similar TBBPA conversions and debromination ratios were observed for the cases of sparging N 2 only and sparging N 2 followed by air, which were higher than those of aeration. Reductive debromination occurred while first bubbling N 2 , forming tri-BBPA, di-BBPA, mono-BBPA and BPA; and these intermediates were likely to be further oxidized by OH generated from H 2 O 2 together with Pd-Fe/Ni electrode under aeration. Reductive and oxidative intermediates (including aromatic ring-opened product) were identified by HPLC and UPLC-QTOF-MS. Based on the intermediates, the possible TBBPA degradation mechanism and pathway were proposed. This study demonstrates that sequential reduction-oxidation process tuned by N 2 and air bubbling was favored for TBBPA degradation, thus, it should be a promising process for HOCs degradation. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Degradation of trichloroethylene (TCE) and polychlorinated biphenyls (PCBs) by Fe and Fe-Pd bimetals in the presence of surfactants and cosolvents

    International Nuclear Information System (INIS)

    Gu, B.; Liang, L.; West, O.R.; Cameron, P.; Davenport, D.

    1997-01-01

    Surfactants and cosolvents are being used to enhance the removal of dense non-aqueous phase liquids (DNAPL) such as trichloroethylene (TCE) and polychlorinated biphenyls (PCBS) from contaminated soils. However, the waste surfactant solution containing TCE and PCBs must be treated before it can be disposed. This study evaluated the use of zero-valence iron and palladized iron fillings on the dechlorination of TCE and a PCB congener in a dihexylsulfosuccinate surfactant solution. Batch experimental results indicated that TCE can be rapidly degraded by palladized iron filings with a half-life of 27.4 min. PCB was degraded at a slower rate than TCE with a half-life ranging from 100 min to 500 min as the concentration of surfactant increased. In column flow-through experiments, both TCE and PCBs degrade at an enhanced rate with a half-life about 1.5 and 6 min because of an increased solid to solution ratio in the column than in the batch experiments. Results of this work suggest that Fe-Pd filings may be potentially applicable for ex-situ treatment of TCE and PCBs in the surfactant solutions that are generated during surfactant washing of the contaminated soils

  10. Iodinated contrast media electro-degradation: process performance and degradation pathways.

    Science.gov (United States)

    Del Moro, Guido; Pastore, Carlo; Di Iaconi, Claudio; Mascolo, Giuseppe

    2015-02-15

    The electrochemical degradation of six of the most widely used iodinated contrast media was investigated. Batch experiments were performed under constant current conditions using two DSA® electrodes (titanium coated with a proprietary and patented mixed metal oxide solution of precious metals such as iridium, ruthenium, platinum, rhodium and tantalum). The degradation removal never fell below 85% (at a current density of 64 mA/cm(2) with a reaction time of 150 min) when perchlorate was used as the supporting electrolyte; however, when sulphate was used, the degradation performance was above 80% (at a current density of 64 mA/cm(2) with a reaction time of 150 min) for all of the compounds studied. Three main degradation pathways were identified, namely, the reductive de-iodination of the aromatic ring, the reduction of alkyl aromatic amides to simple amides and the de-acylation of N-aromatic amides to produce aromatic amines. However, as amidotrizoate is an aromatic carboxylate, this is added via the decarboxylation reaction. The investigation did not reveal toxicity except for the lower current density used, which has shown a modest toxicity, most likely for some reaction intermediates that are not further degraded. In order to obtain total removal of the contrast media, it was necessary to employ a current intensity between 118 and 182 mA/cm(2) with energy consumption higher than 370 kWh/m(3). Overall, the electrochemical degradation was revealed to be a reliable process for the treatment of iodinated contrast media that can be found in contaminated waters such as hospital wastewater or pharmaceutical waste-contaminated streams. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Characterization of a novel oxyfluorfen-degrading bacterial strain Chryseobacterium aquifrigidense and its biochemical degradation pathway.

    Science.gov (United States)

    Zhao, Huanhuan; Xu, Jun; Dong, Fengshou; Liu, Xingang; Wu, Yanbing; Wu, Xiaohu; Zheng, Yongquan

    2016-08-01

    Persistent use of the diphenyl ether herbicides oxyfluorfen may seriously increase the health risks and ecological safety problems. A newly bacterium R-21 isolated from active soil was able to degrade and utilize oxyfluorfen as the sole carbon source. R-21 was identified as Chryseobacterium aquifrigidense by morphology, physiobiochemical characteristics, and genetic analysis. Under the optimum cultural conditions (pH 6.9, temperature 33.4 °C, and inoculum size 0.2 g L(-1)), R-21 could degrade 92.1 % of oxyfluorfen at 50 mg L(-1) within 5 days. During oxyfluorfen degradation, six metabolites were detected and identified by atmospheric pressure gas chromatography coupled to quadrupole-time of flight mass spectrometry and ultra-performance liquid chromatography coupled to quadrupole-time of flight mass spectrometry, and a plausible degradation pathway was deduced. Strain R-21 is a promising potential in bioremediation of oxyfluorfen-contaminated environments.

  12. Synergistic Processing of Biphenyl and Benzoate: Carbon Flow Through the Bacterial Community in Polychlorinated-Biphenyl-Contaminated Soil.

    Science.gov (United States)

    Leewis, Mary-Cathrine; Uhlik, Ondrej; Leigh, Mary Beth

    2016-02-26

    Aerobic mineralization of PCBs, which are toxic and persistent organic pollutants, involves the upper (biphenyl, BP) and lower (benzoate, BZ) degradation pathways. The activity of different members of the soil microbial community in performing one or both pathways, and their synergistic interactions during PCB biodegradation, are not well understood. This study investigates BP and BZ biodegradation and subsequent carbon flow through the microbial community in PCB-contaminated soil. DNA stable isotope probing (SIP) was used to identify the bacterial guilds involved in utilizing (13)C-biphenyl (unchlorinated analogue of PCBs) and/or (13)C-benzoate (product/intermediate of BP degradation and analogue of chlorobenzoates). By performing SIP with two substrates in parallel, we reveal microbes performing the upper (BP) and/or lower (BZ) degradation pathways, and heterotrophic bacteria involved indirectly in processing carbon derived from these substrates (i.e. through crossfeeding). Substrate mineralization rates and shifts in relative abundance of labeled taxa suggest that BP and BZ biotransformations were performed by microorganisms with different growth strategies: BZ-associated bacteria were fast growing, potentially copiotrophic organisms, while microbes that transform BP were oligotrophic, slower growing, organisms. Our findings provide novel insight into the functional interactions of soil bacteria active in processing biphenyl and related aromatic compounds in soil, revealing how carbon flows through a bacterial community.

  13. Aqueous photodegradation of antibiotic florfenicol: kinetics and degradation pathway studies.

    Science.gov (United States)

    Zhang, Ya; Li, Jianhua; Zhou, Lei; Wang, Guoqing; Feng, Yanhong; Wang, Zunyao; Yang, Xi

    2016-04-01

    The occurrence of antibacterial agents in natural environment was of scientific concern in recent years. As endocrine disrupting chemicals, they had potential risk on ecology system and human beings. In the present study, the photodegradation kinetics and pathways of florfenicol were investigated under solar and xenon lamp irradiation in aquatic systems. Direct photolysis half-lives of florfenicol were determined as 187.29 h under solar irradiation and 22.43 h under xenon lamp irradiation, respectively. Reactive oxygen species (ROS), such as hydroxyl radical (·OH) and singlet oxygen ((1)O2) were found to play an important role in indirect photolysis process. The presence of nitrate and dissolved organic matters (DOMs) could affect photolysis of florfenicol in solutions through light screening effect, quenching effect, and photoinduced oxidization process. Photoproducts of florfenicol in DOMs solutions were identified by solid phase extraction-liquid chromatography-mass spectrometry (SPE-LC-MS) analysis techniques, and degradation pathways were proposed, including photoinduced hydrolysis, oxidation by (1)O2 and ·OH, dechlorination, and cleavage of the side chain.

  14. Ring cleavage and degradative pathway of cyanuric acid in bacteria.

    Science.gov (United States)

    Cook, A M; Beilstein, P; Grossenbacher, H; Hütter, R

    1985-01-01

    The degradative pathway of cyanuric acid [1,3,5-triazine-2,4,6(1H,3H,5H)-trione] was examined in Pseudomonas sp. strain D. The bacterium grew with cyanuric acid, biuret, urea or NH4+ as sole source of nitrogen, and each substrate was entirely metabolized concomitantly with growth. Enzymes from strain D were separated by chromatography on DEAE-cellulose and three reactions were examined. Cyanuric acid (1 mol) was converted stoichiometrically into 1.0 mol of CO2 and 1.1 mol of biuret, which was conclusively identified. Biuret (1 mol) was converted stoichiometrically into 1.1 mol of NH4+, about 1 mol of CO2 and 1.0 mol of urea, which was conclusively identified. Urea (1 mol) was converted into 1.9 mol of NH4+ and 1.0 mol of CO2. The reactions proceeded under aerobic or anoxic conditions and were presumed to be hydrolytic. Data indicate that the same pathway occurred in another pseudomonad and a strain of Klebsiella pneumoniae. PMID:3904735

  15. Degradation of diclofenac by ultrasonic irradiation: kinetic studies and degradation pathways.

    Science.gov (United States)

    Nie, Er; Yang, Mo; Wang, Dong; Yang, Xiaoying; Luo, Xingzhang; Zheng, Zheng

    2014-10-01

    Diclofenac (DCF) is a widely used anti-inflammatory drug found in various water bodies, posing threats to human health. In this research, the effects of ultrasonic irradiation at 585kHz on the degradation of DCF were studied under the air, oxygen, argon, and nitrogen saturated conditions. First, the dechlorination efficiencies under the air, oxygen, argon, and nitrogen saturated conditions were calculated to be 67%, 60%, 53% and 59%. Second, there was full mineralization of nitrogen during DCF degradation under the air, oxygen, and argon saturated conditions, but no mineralization of nitrogen under the nitrogen-saturated condition. Different from nitrogen, only partial mineralization of carbon occurred under the four gas-saturated conditions. Third, OH scavengers were added to derive the rate constants in the three reaction zones: cavitation bubble, supercritical interface, and bulk solution. Comparison of the constants indicated that DCF degradation was not limited to the bulk solution as conventionally assumed. Oxidation in the supercritical interface played a dominant role under the air and oxygen saturated conditions, while OH reactions in the cavitation bubble and/or bulk solution were dominant under the nitrogen and argon saturated conditions. After the addition of H2O2, reactions in the cavitation bubble and bulk solution kept their dominant roles under the nitrogen and argon saturated conditions, while reaction in the supercritical interface decreased under the air and oxygen saturated conditions. Finally, LC-MS analysis was used to derive the by-products and propose the main pathways of DCF degradation by ultrasonic irradiation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. DEGRADATION BY PULSED CORONA DISCHARGES: STUDY ON THE POSSIBLE CHEMICAL DEGRADATION PATHWAY FOR DICLOFENAC

    OpenAIRE

    TORRES-GODOY, CYNTHIA

    2012-01-01

    The remo val of hazardous organic pollutants such as polychlorinated biphenyls (PCB's), polycyclic aromatic hydrocarbons (benzopyrene, dibenzoanthracene), pesticides (DDT, lindane), and pharmaceutical products ( diclofenac, ibuprofen, carbamazepine) from waste water is a growing concem in environmental science and technology. Therefore, innovative methods for water remediation in removing contaminants from waste sites need to be examined. This work explores the use of Pulsed Corona Disc...

  17. Fenton degradation of Cartap hydrochloride: identification of the main intermediates and the degradation pathway.

    Science.gov (United States)

    Tian, Kaixun; Ming, Cuixiang; Dai, Youzhi; Honore Ake, Kouassi Marius

    2015-01-01

    The advanced oxidation of Cartap hydrochloride (Cartap) promoted by the Fenton system in an aqueous medium was investigated. Based on total organic carbon, chemical oxygen demand and high-performance liquid chromatography, the oxidation of Cartap is quite efficient by the Fenton system. Its long chain is easily destroyed, but the reaction does not proceed to complete mineralization. Ion chromatography detection indicated the formation of acetic acid, propionic acid, formic acid, nitrous acid and sulfuric acid in the reaction mixtures. Further evidence of nitrogen monoxide and sulfur dioxide formation was obtained by using a flue gas analyzer. Monitoring by gas chromatograph-mass spectrometer demonstrated the formation of oxalic acid, ethanol, carbon dioxide, and L-alanine ethylamide. Based on these experimental results, plausible degradation pathways for Cartap mineralization in an aqueous medium by the Fenton system are proposed.

  18. Degradation of polyvinyl alcohol (PVA) by UV/chlorine oxidation: Radical roles, influencing factors, and degradation pathway.

    Science.gov (United States)

    Ye, Bei; Li, Yue; Chen, Zhuo; Wu, Qian-Yuan; Wang, Wen-Long; Wang, Ting; Hu, Hong-Ying

    2017-11-01

    Polyvinyl alcohol (PVA) is widely used in industry but is difficult to degrade. In this study, the synergistic effect of UV irradiation and chlorination on degradation of PVA was investigated. UV irradiation or chlorination alone did not degrade PVA. By contrast, UV/chlorine oxidation showed good efficiency for PVA degradation via generation of active free radicals, such as OH and Cl. The relative importance of these two free radicals in the oxidation process was evaluated, and it was shown that OH contributed more to PVA degradation than Cl did. The degradation of PVA followed pseudo first order kinetics. The rate constant k increased linearly from 0 min -1 to 0.3 min -1 with increasing chlorine dosage in range of 0 mg/L to 20 mg/L. However, when the chlorine dosage was increased above 20 mg/L, scavenging effect of free radicals occurred, and the degradation efficiency of PVA did not increase much more. Acidic media increased the degradation efficiency of PVA by UV/chlorine oxidation more than basic or neutral media because of the higher ratio of [HOCl]/[OCl - ], higher free radical quantum yields, and the lower free radical quenching effect under acidic conditions. Results of Fourier Transform Infrared Spectroscopy showed that carbonyl groups in degradation products were formed during UV/chlorine oxidation, and a possible degradation pathway via alcohol to carbonyl was proposed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Exploring the Degradation of Ibuprofen by Bacillus thuringiensis B1(2015b: The New Pathway and Factors Affecting Degradation

    Directory of Open Access Journals (Sweden)

    Ariel Marchlewicz

    2017-10-01

    Full Text Available Ibuprofen is one of the most often detected pollutants in the environment, particularly at landfill sites and in wastewaters. Contamination with pharmaceuticals is often accompanied by the presence of other compounds which may influence their degradation. This work describes the new degradation pathway of ibuprofen by Bacillus thuringiensis B1(2015b, focusing on enzymes engaged in this process. It is known that the key intermediate which transformation limits the velocity of the degradation process is hydroxyibuprofen. As the degradation rate also depends on various factors, the influence of selected heavy metals and aromatic compounds on ibuprofen degradation by the B1(2015b strain was examined. Based on the values of non-observed effect concentration (NOEC it was found that the toxicity of tested metals increases from Hg(II < Cu(II < Cd(II < Co(II < Cr(VI. Despite the toxic effect of metals, the biodegradation of ibuprofen was observed. The addition of Co2+ ions into the medium significantly extended the time necessary for the complete removal of ibuprofen. It was shown that Bacillus thuringiensis B1(2015b was able to degrade ibuprofen in the presence of phenol, benzoate, and 2-chlorophenol. Moreover, along with the removal of ibuprofen, degradation of phenol and benzoate was observed. Introduction of 4-chlorophenol into the culture completely inhibits degradation of ibuprofen.

  20. Modeling position-specific isotope fractionation of organic micropollutants degradation via different reaction pathways

    DEFF Research Database (Denmark)

    Jin, Biao; Rolle, Massimo

    : dichlorobenzamide (BAM), isoproturon (IPU) and diclofenac (DCF). The model successfully reproduces the multi-element isotope data, and precisely captures the dual element isotope trends, characterizing the different degradation pathways. Besides illustrating the model capability of mechanistic evaluation...

  1. Degradation of diclofenac by UV-activated persulfate process: Kinetic studies, degradation pathways and toxicity assessments.

    Science.gov (United States)

    Lu, Xian; Shao, Yisheng; Gao, Naiyun; Chen, Juxiang; Zhang, Yansen; Xiang, Huiming; Guo, Youluo

    2017-07-01

    Diclofenac (DCF) is the frequently detected non-steroidal pharmaceuticals in the aquatic environment. In this study, the degradation of DCF was evaluated by UV-254nm activated persulfate (UV/PS). The degradation of DCF followed the pseudo first-order kinetics pattern. The degradation rate constant (k obs ) was accelerated by UV/PS compared to UV alone and PS alone. Increasing the initial PS dosage or solution pH significantly enhanced the degradation efficiency. Presence of various natural water constituents had different effects on DCF degradation, with an enhancement or inhibition in the presence of inorganic anions (HCO 3 - or Cl - ) and a significant inhibition in the presence of NOM. In addition, preliminary degradation mechanisms and major products were elucidated using LC-MS/MS. Hydroxylation, decarbonylation, ring-opening and cyclation reaction involving the attack of SO 4 • - or other substances, were the main degradation mechanism. TOC analyzer and Microtox bioassay were employed to evaluate the mineralization and cytotoxicity of solutions treated by UV/PS at different times, respectively. Limited elimination of TOC (32%) was observed during the mineralization of DCF. More toxic degradation products and their related intermediate species were formed, and the UV/PS process was suitable for removing the toxicity. Of note, longer degradation time may be considered for the final toxicity removal. Copyright © 2017. Published by Elsevier Inc.

  2. Complementary roles of intracellular and pericellular collagen degradation pathways in vivo

    DEFF Research Database (Denmark)

    Wagenaar-Miller, Rebecca A; Engelholm, Lars H; Gavard, Julie

    2007-01-01

    Collagen degradation is essential for cell migration, proliferation, and differentiation. Two key turnover pathways have been described for collagen: intracellular cathepsin-mediated degradation and pericellular collagenase-mediated degradation. However, the functional relationship between these ...... failure and poor survival of cartilage- and bone-forming cells within their collagen-rich microenvironment. These findings have important implications for the use of pharmacological inhibitors of collagenase activity to prevent connective tissue destruction in a variety of diseases....

  3. Draft Genome Sequence of Cupriavidus pauculus Strain KF709, a Biphenyl-Utilizing Bacterium Isolated from Biphenyl-Contaminated Soil.

    Science.gov (United States)

    Watanabe, Takahito; Yamazoe, Atsushi; Hosoyama, Akira; Fujihara, Hidehiko; Suenaga, Hikaru; Hirose, Jun; Futagami, Taiki; Goto, Masatoshi; Kimura, Nobutada; Furukawa, Kensuke

    2015-03-26

    We report the draft genome sequence of Cupriavidus pauculus strain KF709, which comprises 6,826,799 bp with 6,272 coding sequences. The strain KF709 utilizes biphenyl and degrades low-chlorinated biphenyls; however, it possesses fewer coding sequences involved in the degradation of aromatic compounds than other strains belonging to the Betaproteobacteria. Copyright © 2015 Watanabe et al.

  4. Draft Genome Sequence of Cupriavidus pauculus Strain KF709, a Biphenyl-Utilizing Bacterium Isolated from Biphenyl-Contaminated Soil

    OpenAIRE

    Watanabe, Takahito; Yamazoe, Atsushi; Hosoyama, Akira; Fujihara, Hidehiko; Suenaga, Hikaru; Hirose, Jun; Futagami, Taiki; Goto, Masatoshi; Kimura, Nobutada; Furukawa, Kensuke

    2015-01-01

    We report the draft genome sequence of Cupriavidus pauculus strain KF709, which comprises 6,826,799 bp with 6,272 coding sequences. The strain KF709 utilizes biphenyl and degrades low-chlorinated biphenyls; however, it possesses fewer coding sequences involved in the degradation of aromatic compounds than other strains belonging to the Betaproteobacteria.

  5. The Vacuolar Import and Degradation Pathway Merges with the Endocytic Pathway to Deliver Fructose-1,6-bisphosphatase to the Vacuole for Degradation*

    Science.gov (United States)

    Brown, C. Randell; Wolfe, Allison B.; Cui, Dongying; Chiang, Hui-Ling

    2008-01-01

    The gluconeogenic enzyme fructose-1,6-bisphosphatase (FBPase) is degraded in the vacuole when glucose is added to glucose-starved cells. Before it is delivered to the vacuole, however, FBPase is imported into intermediate carriers called Vid (vacuole import and degradation) vesicles. Here, using biochemical and genetic approaches, we identified a requirement for SEC28 in FBPase degradation. SEC28 encodes the ε-COP subunit of COPI (coat protein complex I) coatomer proteins. When SEC28 and other coatomer genes were mutated, FBPase degradation was defective and FBPase association with Vid vesicles was impaired. Coatomer proteins were identified as components of Vid vesicles, and they formed a protein complex with a Vid vesicle-specific protein, Vid24p. Furthermore, Vid24p association with Vid vesicles was impaired when coatomer genes were mutated. Kinetic studies indicated that Sec28p traffics to multiple locations. Sec28p was in Vid vesicles, endocytic compartments, and the vacuolar membrane in various mutants that block the FBPase degradation pathway. Sec28p was also found in vesicles adjacent to the vacuolar membrane in the ret2-1 coatomer mutant. We propose that Sec28p resides in Vid vesicles, and these vesicles converge with the endocytic pathway. After fusion, Sec28p is distributed on the vacuolar membrane, where it concentrates on vesicles that pinch off from this organelle. FBPase also utilizes the endocytic pathway for transport to the vacuole, as demonstrated by its presence in endocytic compartments in the Δvph1 mutant. Taken together, our results indicate a strong connection between the Vid trafficking pathway and the endocytic pathway. PMID:18660504

  6. The vacuolar import and degradation pathway merges with the endocytic pathway to deliver fructose-1,6-bisphosphatase to the vacuole for degradation.

    Science.gov (United States)

    Brown, C Randell; Wolfe, Allison B; Cui, Dongying; Chiang, Hui-Ling

    2008-09-19

    The gluconeogenic enzyme fructose-1,6-bisphosphatase (FBPase) is degraded in the vacuole when glucose is added to glucose-starved cells. Before it is delivered to the vacuole, however, FBPase is imported into intermediate carriers called Vid (vacuole import and degradation) vesicles. Here, using biochemical and genetic approaches, we identified a requirement for SEC28 in FBPase degradation. SEC28 encodes the epsilon-COP subunit of COPI (coat protein complex I) coatomer proteins. When SEC28 and other coatomer genes were mutated, FBPase degradation was defective and FBPase association with Vid vesicles was impaired. Coatomer proteins were identified as components of Vid vesicles, and they formed a protein complex with a Vid vesicle-specific protein, Vid24p. Furthermore, Vid24p association with Vid vesicles was impaired when coatomer genes were mutated. Kinetic studies indicated that Sec28p traffics to multiple locations. Sec28p was in Vid vesicles, endocytic compartments, and the vacuolar membrane in various mutants that block the FBPase degradation pathway. Sec28p was also found in vesicles adjacent to the vacuolar membrane in the ret2-1 coatomer mutant. We propose that Sec28p resides in Vid vesicles, and these vesicles converge with the endocytic pathway. After fusion, Sec28p is distributed on the vacuolar membrane, where it concentrates on vesicles that pinch off from this organelle. FBPase also utilizes the endocytic pathway for transport to the vacuole, as demonstrated by its presence in endocytic compartments in the Deltavph1 mutant. Taken together, our results indicate a strong connection between the Vid trafficking pathway and the endocytic pathway.

  7. 3'-5' RNA degradation pathways in human cells

    DEFF Research Database (Denmark)

    Lubas, Michal Szymon

    RNA synthesis and degradation are key steps in the regulation of gene expression in all living organisms. During the course of his PhD studies, Michal Lubas centred his research on the nuclear and cytoplasmic RNA turnover of both noncoding and coding RNAs in human cells. His proteomic studies rev...

  8. Degradation pathway of malachite green in a novel dual-tank photoelectrochemical catalytic reactor

    International Nuclear Information System (INIS)

    Diao, Zenghui; Li, Mingyu; Zeng, Fanyin; Song, Lin; Qiu, Rongliang

    2013-01-01

    Highlights: • A novel dual-tank photoelectrochemical catalytic reactor was designed. • Malachite green degraded in bipolar double-effect mode. • Salt bridge replaced by a cation exchange membrane in the reactor. • Degradation pathways of malachite green in the cathode and anode tanks were similar. -- Abstract: A novel dual-tank photoelectrochemical catalytic reactor was designed to investigate the degradation pathway of malachite green. A thermally formed TiO 2 /Ti thin film electrode was used as photoanode, graphite was used as cathode, and a saturated calomel electrode was employed as the reference electrode in the reactor. In the reactor, the anode and cathode tanks were connected by a cation exchange membrane. Results showed that the decolorization ratio of malachite green in the anode and cathode was 98.5 and 96.5% after 120 min, respectively. Malachite green in the two anode and cathode tanks was oxidized, achieving the bipolar double effect. Malachite green in both the anode and cathode tanks exhibited similar catalytic degradation pathways. The double bond of the malachite green molecule was attacked by strong oxidative hydroxyl radicals, after which the organic compound was degraded by the two pathways into 4,4-bis(dimethylamino) benzophenone, 4-(dimethylamino) benzophenone, 4-(dimethylamino) phenol, and other intermediate products. Eventually, malachite green was degraded into oxalic acid as a small molecular organic acid, which was degraded by processes such as demethylation, deamination, nitration, substitution, addition, and other reactions

  9. Degradation pathway of malachite green in a novel dual-tank photoelectrochemical catalytic reactor

    Energy Technology Data Exchange (ETDEWEB)

    Diao, Zenghui [Department of Environmental Engineering, Jinan University, Guangzhou 510630 (China); School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275 (China); Li, Mingyu, E-mail: tlimy@jnu.edu.cn [Department of Environmental Engineering, Jinan University, Guangzhou 510630 (China); Zeng, Fanyin; Song, Lin [Department of Environmental Engineering, Jinan University, Guangzhou 510630 (China); Qiu, Rongliang [School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275 (China)

    2013-09-15

    Highlights: • A novel dual-tank photoelectrochemical catalytic reactor was designed. • Malachite green degraded in bipolar double-effect mode. • Salt bridge replaced by a cation exchange membrane in the reactor. • Degradation pathways of malachite green in the cathode and anode tanks were similar. -- Abstract: A novel dual-tank photoelectrochemical catalytic reactor was designed to investigate the degradation pathway of malachite green. A thermally formed TiO{sub 2}/Ti thin film electrode was used as photoanode, graphite was used as cathode, and a saturated calomel electrode was employed as the reference electrode in the reactor. In the reactor, the anode and cathode tanks were connected by a cation exchange membrane. Results showed that the decolorization ratio of malachite green in the anode and cathode was 98.5 and 96.5% after 120 min, respectively. Malachite green in the two anode and cathode tanks was oxidized, achieving the bipolar double effect. Malachite green in both the anode and cathode tanks exhibited similar catalytic degradation pathways. The double bond of the malachite green molecule was attacked by strong oxidative hydroxyl radicals, after which the organic compound was degraded by the two pathways into 4,4-bis(dimethylamino) benzophenone, 4-(dimethylamino) benzophenone, 4-(dimethylamino) phenol, and other intermediate products. Eventually, malachite green was degraded into oxalic acid as a small molecular organic acid, which was degraded by processes such as demethylation, deamination, nitration, substitution, addition, and other reactions.

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

    Science.gov (United States)

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

    2012-05-01

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

  11. Exploring the Ubiquitin-Proteasome Protein Degradation Pathway in Yeast

    Science.gov (United States)

    Will, Tamara J.; McWatters, Melissa K.; McQuade, Kristi L.

    2006-01-01

    This article describes an undergraduate biochemistry laboratory investigating the ubiquitin-proteasome pathway in yeast. In this exercise, the enzyme beta-galactosidase (beta-gal) is expressed in yeast under the control of a stress response promoter. Following exposure to heat stress to induce beta-gal expression, cycloheximide is added to halt…

  12. PHOSPHOLIPIDS OF FIVE PSEUDOMONAD ARCHETYPES FOR DIFFERENT TOLUENE DEGRADATION PATHWAYS

    Science.gov (United States)

    Liquid chromatography/electrospray ionization/mass spectrometry (LC/ESI/MS) was used to determine phospholipid profiles for five reference pseudomonad strains harboring distinct toluene catabolic pathways: Pseudomonas putida mt-2, Pseudomonas putida F1, Burkholderia cepacia G4, B...

  13. Pathways for degradation of plastic polymers floating in the marine environment.

    Science.gov (United States)

    Gewert, Berit; Plassmann, Merle M; MacLeod, Matthew

    2015-09-01

    Each year vast amounts of plastic are produced worldwide. When released to the environment, plastics accumulate, and plastic debris in the world's oceans is of particular environmental concern. More than 60% of all floating debris in the oceans is plastic and amounts are increasing each year. Plastic polymers in the marine environment are exposed to sunlight, oxidants and physical stress, and over time they weather and degrade. The degradation processes and products must be understood to detect and evaluate potential environmental hazards. Some attention has been drawn to additives and persistent organic pollutants that sorb to the plastic surface, but so far the chemicals generated by degradation of the plastic polymers themselves have not been well studied from an environmental perspective. In this paper we review available information about the degradation pathways and chemicals that are formed by degradation of the six plastic types that are most widely used in Europe. We extrapolate that information to likely pathways and possible degradation products under environmental conditions found on the oceans' surface. The potential degradation pathways and products depend on the polymer type. UV-radiation and oxygen are the most important factors that initiate degradation of polymers with a carbon-carbon backbone, leading to chain scission. Smaller polymer fragments formed by chain scission are more susceptible to biodegradation and therefore abiotic degradation is expected to precede biodegradation. When heteroatoms are present in the main chain of a polymer, degradation proceeds by photo-oxidation, hydrolysis, and biodegradation. Degradation of plastic polymers can lead to low molecular weight polymer fragments, like monomers and oligomers, and formation of new end groups, especially carboxylic acids.

  14. Oxidative degradation of BPA using TiO2 in water, and transition of estrogenic activity in the degradation pathways.

    Science.gov (United States)

    Nomiyama, Kei; Tanizaki, Teiji; Koga, Toyokazu; Arizono, Koji; Shinohara, Ryota

    2007-01-01

    The oxidative degradation behavior of bisphenol A (BPA) using titanium dioxide (TiO(2)) in water was investigated. The main purposes were to clarify the relationship with estrogenic activity from the degradation pathways demonstrated by oxidation of BPA in water. Approximately 99% of the BPA decomposed within 300 min, and gas chromatography (GC) mass spectrometry (MS) and liquid chromatography (LC) MS analysis revealed many intermediates during the degradation process. Intermediates by decomposition of BPA, such as hydroxylated-BPA (OH-BPA), carboxylic intermediates, phenolic intermediates, and other intermediates produced by the cleavage of a benzene ring were identified and quantified. Estrogenic activities of the degradation pathways of the BPA in water were assessed by using a constructed yeast two-hybrid assay system for human estrogen receptor alpha (hERalpha) and Japanese medaka fish (Oryzias latipes) estrogen receptor alpha (medERalpha). Estrogenic activity for hERalpha and medERalpha was reduced to less than 20% of the initial activity for BPA after 240 min of UV irradiation. However, estrogenic activity for medERalpha was increased by 110% from the initial activity for BPA at 60 min of UV irradiation. It was estimated that medERalpha assay was more sensitive for BPA and the intermediates than was the hERalpha assay. From these findings, we estimate that the intermediates by the oxidation of BPA have the behaviors of xenoestrogen to the aquatic wildlife in the environment.

  15. Photocatalytic degradation of triazophos in aqueous titanium dioxide suspension: Identification of intermediates and degradation pathways

    International Nuclear Information System (INIS)

    Aungpradit, T.; Sutthivaiyakit, P.; Martens, D.; Sutthivaiyakit, S.; Kettrup, A.A.F.

    2007-01-01

    The photocatalytic degradation of triazophos in aqueous TiO 2 suspension has been studied in a photoreactor operating with simulated solar radiation. The decrease in triazophos concentration followed first-order kinetics with a half-life of 4.76 ± 0.42 h at a TiO 2 suspension concentration of 10 mg/L. Seventeen degradation products were identified using HPLC-UV, HPLC/MS/MS, GC/MS/MS and IC, and by comparing retention times and spectra with commercially available authentic standards. On the basis of the observed transformation products, two routes were proposed, one based on the initial oxidative cleavage of P = S bond to P = O bond, and the other on initial cleavage of the ester P-O bonds. Photocatalysis holds promise for the solar treatment of pesticide-contaminated waters

  16. Photocatalytic degradation of triazophos in aqueous titanium dioxide suspension: Identification of intermediates and degradation pathways

    Energy Technology Data Exchange (ETDEWEB)

    Aungpradit, T. [Postgraduate Education and Research Program in Analytical Chemistry, Department of Chemistry, PO Box 1011 Kasetsart, Kasetsart University, Bangkok 10903 (Thailand); Sutthivaiyakit, P. [Postgraduate Education and Research Program in Analytical Chemistry, Department of Chemistry, PO Box 1011 Kasetsart, Kasetsart University, Bangkok 10903 (Thailand)]. E-mail: fscipws@ku.ac.th; Martens, D. [Department of Ecological Chemistry and Environmental Analysis, Technical University of Munich, D-85350 Freising-Weihenstephan (Germany); Institute of Ecological Chemistry, GSF-National Research Centre for Environment and Health, Ingoldstaedter Landstrasse 1, 85764 Neuherberg (Germany); Sutthivaiyakit, S. [Department of Chemistry, Faculty of Science, Ramkhamhaeng University, Bangkok 10240 (Thailand); Kettrup, A.A.F. [Department of Ecological Chemistry and Environmental Analysis, Technical University of Munich, D-85350 Freising-Weihenstephan (Germany); Institute of Ecological Chemistry, GSF-National Research Centre for Environment and Health, Ingoldstaedter Landstrasse 1, 85764 Neuherberg (Germany)

    2007-07-19

    The photocatalytic degradation of triazophos in aqueous TiO{sub 2} suspension has been studied in a photoreactor operating with simulated solar radiation. The decrease in triazophos concentration followed first-order kinetics with a half-life of 4.76 {+-} 0.42 h at a TiO{sub 2} suspension concentration of 10 mg/L. Seventeen degradation products were identified using HPLC-UV, HPLC/MS/MS, GC/MS/MS and IC, and by comparing retention times and spectra with commercially available authentic standards. On the basis of the observed transformation products, two routes were proposed, one based on the initial oxidative cleavage of P = S bond to P = O bond, and the other on initial cleavage of the ester P-O bonds. Photocatalysis holds promise for the solar treatment of pesticide-contaminated waters.

  17. Kinetics and Novel Degradation Pathway of Permethrin in Acinetobacter baumannii ZH-14

    Directory of Open Access Journals (Sweden)

    Hui Zhan

    2018-02-01

    Full Text Available Persistent use of permethrin has resulted in its ubiquitous presence as a contaminant in surface streams and soils, yet little is known about the kinetics and metabolic behaviors of this pesticide. In this study, a novel bacterial strain Acinetobacter baumannii ZH-14 utilizing permethrin via partial hydrolysis pathways was isolated from sewage sludge. Response surface methodology based on Box-Behnken design of cultural conditions was used for optimization resulting in 100% degradation of permethrin (50 mg·L−1 within 72 h. Strain ZH-14 degraded permethrin up to a concentration of 800 mg·L−1. Biodegradation kinetics analysis indicated that permethrin degradation by this strain was concentration dependent, with a maximum specific degradation rate, half-saturation constant, and inhibition constant of 0.0454 h−1, 4.7912 mg·L−1, and 367.2165 mg·L−1, respectively. High-performance liquid chromatography and gas chromatography-mass spectrometry identified 3-phenoxybenzenemethanol and 3-phenoxybenzaldehyde as the major intermediate metabolites of the permethrin degradation pathway. Bioaugmentation of permethrin-contaminated soils with strain ZH-14 significantly enhanced degradation, and over 85% of permethrin was degraded within 9 days with the degradation process following the first-order kinetic model. In addition to degradation of permethrin, strain ZH-14 was capable of degrading a large range of synthetic pyrethroids such as deltamethrin, bifenthrin, fenpropathrin, cyhalothrin, and beta-cypermethrin which are also widely used pesticides with environmental contamination problems, suggesting the promising potentials of A. baumannii ZH-14 in bioremediation of pyrethroid-contaminated terrestrial and aquatic environments.

  18. Sulfate radical degradation of acetaminophen by novel iron-copper bimetallic oxidation catalyzed by persulfate: Mechanism and degradation pathways

    Science.gov (United States)

    Zhang, Yuanchun; Zhang, Qian; Hong, Junming

    2017-11-01

    A novel iron coupled copper oxidate (Fe2O3@Cu2O) catalyst was synthesized to activate persulfate (PS) for acetaminophen (APAP) degradation. The catalysts were characterized via field-emission scanning electron microscopy and energy-dispersive X-ray spectrometry. The effects of the catalyst, PS concentration, catalyst dosage, initial pH, dissolved oxygen were analyzed for treatment optimization. Results indicated that Fe2O3@Cu2O achieved higher efficiency in APAP degradation than Fe2O3/PS and Cu2O/PS systems. The optimal removal efficiency of APAP (90%) was achieved within 40 min with 0.6 g/L PS and 0.3 g/L catalyst. To clarify the mechanism for APAP degradation, intermediates were analyzed with gas chromatography-mass spectrometry. Three possible degradation pathways were identified. During reaction, Cu(I) was found to react with Fe(III) to generate Fe(II), which is the most active phase for PS activation. Through the use of methanol and tert-butyl alcohol (TBA) as radical trappers, SO4rad - was identified as the main radical species that is generated during oxidation.

  19. Phytoalexins of the Pyrinae: Biphenyls and dibenzofurans

    Directory of Open Access Journals (Sweden)

    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.

  20. RNAi screening for characterisation of ER-associated degradation pathways in mammalian cells

    DEFF Research Database (Denmark)

    Månsson, Mats David Joakim

    fluorescence-based RNAi screens in mammalian cells on TCR-α-GFP and HANSκLC, for identification of ERAD pathways. By validating the obtained screening hits we concluded that UBE2J2 is involved in TCR-α-GFP degradation, possibly by ubiquitination of C-terminal serine residues in TCR-α-GFP. Additionally, we also...

  1. Tuning biphenyl dioxygenase for extended substrate specificity

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-06-05

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

  2. New Hydrocarbon Degradation Pathways in the Microbial Metagenome from Brazilian Petroleum Reservoirs

    Science.gov (United States)

    Sierra-García, Isabel Natalia; Correa Alvarez, Javier; Pantaroto de Vasconcellos, Suzan; Pereira de Souza, Anete; dos Santos Neto, Eugenio Vaz; de Oliveira, Valéria Maia

    2014-01-01

    Current knowledge of the microbial diversity and metabolic pathways involved in hydrocarbon degradation in petroleum reservoirs is still limited, mostly due to the difficulty in recovering the complex community from such an extreme environment. Metagenomics is a valuable tool to investigate the genetic and functional diversity of previously uncultured microorganisms in natural environments. Using a function-driven metagenomic approach, we investigated the metabolic abilities of microbial communities in oil reservoirs. Here, we describe novel functional metabolic pathways involved in the biodegradation of aromatic compounds in a metagenomic library obtained from an oil reservoir. Although many of the deduced proteins shared homology with known enzymes of different well-described aerobic and anaerobic catabolic pathways, the metagenomic fragments did not contain the complete clusters known to be involved in hydrocarbon degradation. Instead, the metagenomic fragments comprised genes belonging to different pathways, showing novel gene arrangements. These results reinforce the potential of the metagenomic approach for the identification and elucidation of new genes and pathways in poorly studied environments and contribute to a broader perspective on the hydrocarbon degradation processes in petroleum reservoirs. PMID:24587220

  3. Degradation of Reactive Yellow X-RG by O3/Fenton system: response surface approach, reaction mechanism, and degradation pathway.

    Science.gov (United States)

    Shen, Yongjun; Xu, Qihui; Liang, Jun; Xu, Wei

    2016-11-01

    O 3 /Fenton for the treatment of effluent containing Reactive Yellow X-RG is investigated. The response surface methodology is applied to study the main and interactive effects of the parameters. With the initial dye concentration being controlled at 300 mg L -1 , the optimized conditions for wastewater treatment are 3.68, 29.19 and 18.49 mg min -1 for initial pH, mole ratio of [H 2 O 2 ]/[Fe 2+ ] and ozone dosage, respectively. The regression quadratic model well describing the degradation efficiency of O 3 /Fenton process is developed and validated by the analysis of variances, respectively. In addition, a possible pathway for Reactive Yellow X-RG degradation is proposed by detecting the temporal evolution of intermediates in the solution, with the use of some techniques including ultraviolet spectrophotometric method (UV-Vis), Fourier transform infrared spectroscopy (FT-IR) and gas chromatography-mass spectrometry (GC/MS). Meanwhile, every reaction step is given to explain the degradation mechanisms.

  4. Degradation of ibuprofen by hydrodynamic cavitation: Reaction pathways and effect of operational parameters.

    Science.gov (United States)

    Musmarra, Dino; Prisciandaro, Marina; Capocelli, Mauro; Karatza, Despina; Iovino, Pasquale; Canzano, Silvana; Lancia, Amedeo

    2016-03-01

    Ibuprofen (IBP) is an anti-inflammatory drug whose residues can be found worldwide in natural water bodies resulting in harmful effects to aquatic species even at low concentrations. This paper deals with the degradation of IBP in water by hydrodynamic cavitation in a convergent-divergent nozzle. Over 60% of ibuprofen was degraded in 60 min with an electrical energy per order (EEO) of 10.77 kWh m(-3) at an initial concentration of 200 μg L(-1) and a relative inlet pressure pin=0.35 MPa. Five intermediates generated from different hydroxylation reactions were identified; the potential mechanisms of degradation were sketched and discussed. The reaction pathways recognized are in line with the relevant literature, both experimental and theoretical. By varying the pressure upstream the constriction, different degradation rates were observed. This effect was discussed according to a numerical simulation of the hydroxyl radical production identifying a clear correspondence between the maximum kinetic constant kOH and the maximum calculated OH production. Furthermore, in the investigated experimental conditions, the pH parameter was found not to affect the extent of degradation; this peculiar feature agrees with a recently published kinetic insight and has been explained in the light of the intermediates of the different reaction pathways. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Camptothecin resistance is determined by the regulation of topoisomerase I degradation mediated by ubiquitin proteasome pathway.

    Science.gov (United States)

    Ando, Koji; Shah, Ankur K; Sachdev, Vibhu; Kleinstiver, Benjamin P; Taylor-Parker, Julian; Welch, Moira M; Hu, Yiheng; Salgia, Ravi; White, Forest M; Parvin, Jeffrey D; Ozonoff, Al; Rameh, Lucia E; Joung, J Keith; Bharti, Ajit K

    2017-07-04

    Proteasomal degradation of topoisomerase I (topoI) is one of the most remarkable cellular phenomena observed in response to camptothecin (CPT). Importantly, the rate of topoI degradation is linked to CPT resistance. Formation of the topoI-DNA-CPT cleavable complex inhibits DNA re-ligation resulting in DNA-double strand break (DSB). The degradation of topoI marks the first step in the ubiquitin proteasome pathway (UPP) dependent DNA damage response (DDR). Here, we show that the Ku70/Ku80 heterodimer binds with topoI, and that the DNA-dependent protein kinase (DNA-PKcs) phosphorylates topoI on serine 10 (topoI-pS10), which is subsequently ubiquitinated by BRCA1. A higher basal level of topoI-pS10 ensures rapid topoI degradation leading to CPT resistance. Importantly, PTEN regulates DNA-PKcs kinase activity in this pathway and PTEN deletion ensures DNA-PKcs dependent higher topoI-pS10, rapid topoI degradation and CPT resistance.

  6. Differential impact of diverse anticancer chemotherapeutics on the Cdc25A-degradation checkpoint pathway

    International Nuclear Information System (INIS)

    Agner, Jeppe; Falck, Jacob; Lukas, Jiri; Bartek, Jiri

    2005-01-01

    When exposed to DNA-damaging insults such as ionizing radiation (IR) or ultraviolet light (UV), mammalian cells activate checkpoint pathways to halt cell cycle progression or induce cell death. Here we examined the ability of five commonly used anticancer drugs with different mechanisms of action to activate the Chk1/Chk2-Cdc25A-CDK2/cyclin E cell cycle checkpoint pathway, previously shown to be induced by IR or UV. Whereas exposure of human cells to topoisomerase inhibitors camptothecin, etoposide, or adriamycin resulted in rapid (within 1 h) activation of the pathway including degradation of the Cdc25A phosphatase and inhibition of cyclin E/CDK2 kinase activity, taxol failed to activate this checkpoint even after a prolonged treatment. Unexpectedly, although the alkylating agent cisplatin also induced degradation of Cdc25A (albeit delayed, after 8-12 h), cyclin E/CDK2 activity was elevated and DNA synthesis continued, a phenomena that correlated with increased E2F1 protein levels and consequently enhanced expression of cyclin E. These results reveal a differential impact of various classes of anticancer chemotherapeutics on the Cdc25A-degradation pathway, and indicate that the kinetics of checkpoint induction, and the relative balance of key components within the DNA damage response network may dictate whether the treated cells arrest their cell cycle progression

  7. Combination of degradation pathways for naphthalene utilization in Rhodococcus sp. strain TFB

    Science.gov (United States)

    Tomás-Gallardo, Laura; Gómez-Álvarez, Helena; Santero, Eduardo; Floriano, Belén

    2014-01-01

    Rhodococcus sp. strain TFB is a metabolic versatile bacterium able to grow on naphthalene as the only carbon and energy source. Applying proteomic, genetic and biochemical approaches, we propose in this paper that, at least, three coordinated but independently regulated set of genes are combined to degrade naphthalene in TFB. First, proteins involved in tetralin degradation are also induced by naphthalene and may carry out its conversion to salicylaldehyde. This is the only part of the naphthalene degradation pathway showing glucose catabolite repression. Second, a salicylaldehyde dehydrogenase activity that converts salicylaldehyde to salicylate is detected in naphthalene-grown cells but not in tetralin-or salicylate-grown cells. Finally, we describe the chromosomally located nag genes, encoding the gentisate pathway for salicylate conversion into fumarate and pyruvate, which are only induced by salicylate and not by naphthalene. This work shows how biodegradation pathways in Rhodococcus sp. strain TFB could be assembled using elements from different pathways mainly because of the laxity of the regulatory systems and the broad specificity of the catabolic enzymes. PMID:24325207

  8. Microwave-Enhanced Photolysis of Norfloxacin: Kinetics, Matrix Effects, and Degradation Pathways.

    Science.gov (United States)

    Liao, Wenchao; Sharma, Virender K; Xu, Su; Li, Qingsong; Wang, Lei

    2017-12-14

    Degradation of norfloxacin (NOR) was studied using a combination of microwave and UV irradiation methods (MW/UV process). Remarkable synergistic effect was found between MW and UV light. The removal rate with the MW/UV process was much faster than that with UV light irradiation only. Degradation of NOR followed second-order kinetics and ~72% of NOR could be removed in the first 5 min of MW/UV reaction. Influence of inorganic ions (cations (K⁺, Mg 2+ , Ca 2+ , Cu 2+ ) and anions (Cl - , SO₄ 2- , NO₃ - , CO₃ 2- )), humic acid (HA) and surfactants (cation, anion, and non-ionic) on the degradation of NOR by the MW/UV process was investigated. Among the ions, Cu 2+ and NO₃ - ions inhibited the degradation of NOR. The presence of HA and surfactants in water showed a slight inhibition on the NOR removal. Furthermore, the NOR degradation in the MW/UV process was primarily caused by the ·OH-photosensitization steps. Seven intermediates formed by the oxidation of NOR were identified and three reaction pathways were proposed. Removals of NOR in tap water (TW), synthetic wastewater (WW), river water (RW), and seawater (SW) were also studied, which demonstrated that the MW/UV process was an effective oxidation technology for degrading fluoroquinolone antibiotics in different water matrices.

  9. Microwave-Enhanced Photolysis of Norfloxacin: Kinetics, Matrix Effects, and Degradation Pathways

    Directory of Open Access Journals (Sweden)

    Wenchao Liao

    2017-12-01

    Full Text Available Degradation of norfloxacin (NOR was studied using a combination of microwave and UV irradiation methods (MW/UV process. Remarkable synergistic effect was found between MW and UV light. The removal rate with the MW/UV process was much faster than that with UV light irradiation only. Degradation of NOR followed second-order kinetics and ~72% of NOR could be removed in the first 5 min of MW/UV reaction. Influence of inorganic ions (cations (K+, Mg2+, Ca2+, Cu2+ and anions (Cl−, SO42−, NO3−, CO32−, humic acid (HA and surfactants (cation, anion, and non-ionic on the degradation of NOR by the MW/UV process was investigated. Among the ions, Cu2+ and NO3− ions inhibited the degradation of NOR. The presence of HA and surfactants in water showed a slight inhibition on the NOR removal. Furthermore, the NOR degradation in the MW/UV process was primarily caused by the ·OH-photosensitization steps. Seven intermediates formed by the oxidation of NOR were identified and three reaction pathways were proposed. Removals of NOR in tap water (TW, synthetic wastewater (WW, river water (RW, and seawater (SW were also studied, which demonstrated that the MW/UV process was an effective oxidation technology for degrading fluoroquinolone antibiotics in different water matrices.

  10. Coordinated Regulation of Species-Specific Hydroxycinnamic Acid Degradation and Siderophore Biosynthesis Pathways in Agrobacterium fabrum

    Science.gov (United States)

    Baude, Jessica; Vial, Ludovic; Villard, Camille; Campillo, Tony; Lavire, Céline; Nesme, Xavier

    2016-01-01

    ABSTRACT The rhizosphere-inhabiting species Agrobacterium fabrum (genomospecies G8 of the Agrobacterium tumefaciens species complex) is known to degrade hydroxycinnamic acids (HCAs), especially ferulic acid and p-coumaric acid, via the novel A. fabrum HCA degradation pathway. Gene expression profiles of A. fabrum strain C58 were investigated in the presence of HCAs, using a C58 whole-genome oligoarray. Both ferulic acid and p-coumaric acid caused variations in the expression of more than 10% of the C58 genes. Genes of the A. fabrum HCA degradation pathway, together with the genes involved in iron acquisition, were among the most highly induced in the presence of HCAs. Two operons coding for the biosynthesis of a particular siderophore, as well as genes of the A. fabrum HCA degradation pathway, have been described as being specific to the species. We demonstrate here their coordinated expression, emphasizing the interdependence between the iron concentration in the growth medium and the rate at which ferulic acid is degraded by cells. The coordinated expression of these functions may be advantageous in HCA-rich but iron-starved environments in which microorganisms have to compete for both iron and carbon sources, such as in plant roots. The present results confirm that there is cooperation between the A. fabrum-specific genes, defining a particular ecological niche. IMPORTANCE We previously identified seven genomic regions in Agrobacterium fabrum that were specifically present in all of the members of this species only. Here we demonstrated that two of these regions, encoding the hydroxycinnamic acid degradation pathway and the iron acquisition pathway, were regulated in a coordinated manner. The coexpression of these functions may be advantageous in hydroxycinnamic acid-rich but iron-starved environments in which microorganisms have to compete for both iron and carbon sources, such as in plant roots. These data support the view that bacterial genomic species

  11. Metabolic pathway of 3,6-anhydro-D-galactose in carrageenan-degrading microorganisms.

    Science.gov (United States)

    Lee, Sun Bok; Kim, Jeong Ah; Lim, Hyun Seung

    2016-05-01

    Complete hydrolysis of κ-carrageenan produces two sugars, D-galactose and 3,6-anhydro-D-galactose (D-AnG). At present, however, we do not know how carrageenan-degrading microorganisms metabolize D-AnG. In this study, we investigated the metabolic pathway of D-AnG degradation by comparative genomic analysis of Cellulophaga lytica LIM-21, Pseudoalteromonas atlantica T6c, and Epulopiscium sp. N.t. morphotype B, which represent the classes Flavobacteria, Gammaproteobacteria, and Clostridia, respectively. In this bioinformatic analysis, we found candidate common genes that were believed to be involved in D-AnG metabolism. We then experimentally confirmed the enzymatic function of each gene product in the D-AnG cluster. In all three microorganisms, D-AnG metabolizing genes were clustered and organized in operon-like arrangements, which we named as the dan operon (3,6-d-anhydro-galactose). Combining bioinformatic analysis and experimental data, we showed that D-AnG is metabolized to pyruvate and D-glyceraldehyde-3-phosphate via four enzyme-catalyzed reactions in the following route: 3,6-anhydro-D-galactose → 3,6-anhydro-D-galactonate → 2-keto-3-deoxy-D-galactonate (D-KDGal) → 2-keto-3-deoxy-6-phospho-D-galactonate → pyruvate + D-glyceraldehyde-3-phosphate. The pathway of D-AnG degradation is composed of two parts: transformation of D-AnG to D-KDGal using two D-AnG specific enzymes and breakdown of D-KDGal to two glycolysis intermediates using two DeLey-Doudoroff pathway enzymes. To our knowledge, this is the first report on the metabolic pathway of D-AnG degradation.

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

    Science.gov (United States)

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

    2015-01-01

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

  13. Rapid identification and quantitative validation of a caffeine-degrading pathway in Pseudomonas sp. CES.

    Science.gov (United States)

    Yu, Chi Li; Summers, Ryan M; Li, Yalan; Mohanty, Sujit Kumar; Subramanian, Mani; Pope, R Marshall

    2015-01-02

    Understanding the genes and enzymes involved in caffeine metabolism can lead to applications such as production of methylxanthines and environmental waste remediation. Pseudomonas sp. CES may provide insights into these applications, since this bacterium degrades caffeine and thrives in concentrations of caffeine that are three times higher (9.0 g L(-1)) than the maximum tolerable levels of other reported bacteria. We took a novel approach toward identifying the enzymatic pathways in Pseudomonas sp. CES that metabolize caffeine, which largely circumvented the need for exhaustive isolation of enzymes and the stepwise reconstitution of their activities. Here we describe an optimized, rapid alternative strategy based on multiplexed LC-MS/MS assays and show its application by discovering caffeine-degrading enzymes in the CES strain based on quantitative comparison of proteomes from bacteria grown in the absence and presence of caffeine, the latter condition of which was found to have a highly induced capacity for caffeine degradation. Comparisons were made using stable isotope dimethyl labeling, differences in the abundance of particular proteins were substantiated by reciprocal labeling experiments, and the role of the identified proteins in caffeine degradation was independently verified by genetic sequencing. Overall, multiple new components of a N-demethylase system were identified that resulted in rapid pathway validation and gene isolation using this new approach.

  14. Entner-Doudoroff pathway for sulfoquinovose degradation in Pseudomonas putida SQ1.

    Science.gov (United States)

    Felux, Ann-Katrin; Spiteller, Dieter; Klebensberger, Janosch; Schleheck, David

    2015-08-04

    Sulfoquinovose (SQ; 6-deoxy-6-sulfoglucose) is the polar head group of the plant sulfolipid SQ-diacylglycerol, and SQ comprises a major proportion of the organosulfur in nature, where it is degraded by bacteria. A first degradation pathway for SQ has been demonstrated recently, a "sulfoglycolytic" pathway, in addition to the classical glycolytic (Embden-Meyerhof) pathway in Escherichia coli K-12; half of the carbon of SQ is abstracted as dihydroxyacetonephosphate (DHAP) and used for growth, whereas a C3-organosulfonate, 2,3-dihydroxypropane sulfonate (DHPS), is excreted. The environmental isolate Pseudomonas putida SQ1 is also able to use SQ for growth, and excretes a different C3-organosulfonate, 3-sulfolactate (SL). In this study, we revealed the catabolic pathway for SQ in P. putida SQ1 through differential proteomics and transcriptional analyses, by in vitro reconstitution of the complete pathway by five heterologously produced enzymes, and by identification of all four organosulfonate intermediates. The pathway follows a reaction sequence analogous to the Entner-Doudoroff pathway for glucose-6-phosphate: It involves an NAD(+)-dependent SQ dehydrogenase, 6-deoxy-6-sulfogluconolactone (SGL) lactonase, 6-deoxy-6-sulfogluconate (SG) dehydratase, and 2-keto-3,6-dideoxy-6-sulfogluconate (KDSG) aldolase. The aldolase reaction yields pyruvate, which supports growth of P. putida, and 3-sulfolactaldehyde (SLA), which is oxidized to SL by an NAD(P)(+)-dependent SLA dehydrogenase. All five enzymes are encoded in a single gene cluster that includes, for example, genes for transport and regulation. Homologous gene clusters were found in genomes of other P. putida strains, in other gamma-Proteobacteria, and in beta- and alpha-Proteobacteria, for example, in genomes of Enterobacteria, Vibrio, and Halomonas species, and in typical soil bacteria, such as Burkholderia, Herbaspirillum, and Rhizobium.

  15. Rhodococcus erythropolis DCL14 Contains a Novel Degradation Pathway for Limonene

    Science.gov (United States)

    van der Werf, Mariët J.; Swarts, Henk J.; de Bont, Jan A. M.

    1999-01-01

    Strain DCL14, which is able to grow on limonene as a sole source of carbon and energy, was isolated from a freshwater sediment sample. This organism was identified as a strain of Rhodococcus erythropolis by chemotaxonomic and genetic studies. R. erythropolis DCL14 also assimilated the terpenes limonene-1,2-epoxide, limonene-1,2-diol, carveol, carvone, and (−)-menthol, while perillyl alcohol was not utilized as a carbon and energy source. Induction tests with cells grown on limonene revealed that the oxygen consumption rates with limonene-1,2-epoxide, limonene-1,2-diol, 1-hydroxy-2-oxolimonene, and carveol were high. Limonene-induced cells of R. erythropolis DCL14 contained the following four novel enzymatic activities involved in the limonene degradation pathway of this microorganism: a flavin adenine dinucleotide- and NADH-dependent limonene 1,2-monooxygenase activity, a cofactor-independent limonene-1,2-epoxide hydrolase activity, a dichlorophenolindophenol-dependent limonene-1,2-diol dehydrogenase activity, and an NADPH-dependent 1-hydroxy-2-oxolimonene 1,2-monooxygenase activity. Product accumulation studies showed that (1S,2S,4R)-limonene-1,2-diol, (1S,4R)-1-hydroxy-2-oxolimonene, and (3R)-3-isopropenyl-6-oxoheptanoate were intermediates in the (4R)-limonene degradation pathway. The opposite enantiomers [(1R,2R,4S)-limonene-1,2-diol, (1R,4S)-1-hydroxy-2-oxolimonene, and (3S)-3-isopropenyl-6-oxoheptanoate] were found in the (4S)-limonene degradation pathway, while accumulation of (1R,2S,4S)-limonene-1,2-diol from (4S)-limonene was also observed. These results show that R. erythropolis DCL14 metabolizes both enantiomers of limonene via a novel degradation pathway that starts with epoxidation at the 1,2 double bond forming limonene-1,2-epoxide. This epoxide is subsequently converted to limonene-1,2-diol, 1-hydroxy-2-oxolimonene, and 7-hydroxy-4-isopropenyl-7-methyl-2-oxo-oxepanone. This lactone spontaneously rearranges to form 3-isopropenyl-6-oxoheptanoate. In

  16. The deep-subsurface sulfate reducer Desulfotomaculum kuznetsovii employs two methanol-degrading pathways.

    Science.gov (United States)

    Sousa, Diana Z; Visser, Michael; van Gelder, Antonie H; Boeren, Sjef; Pieterse, Mervin M; Pinkse, Martijn W H; Verhaert, Peter D E M; Vogt, Carsten; Franke, Steffi; Kümmel, Steffen; Stams, Alfons J M

    2018-01-16

    Methanol is generally metabolized through a pathway initiated by a cobalamine-containing methanol methyltransferase by anaerobic methylotrophs (such as methanogens and acetogens), or through oxidation to formaldehyde using a methanol dehydrogenase by aerobes. Methanol is an important substrate in deep-subsurface environments, where thermophilic sulfate-reducing bacteria of the genus Desulfotomaculum have key roles. Here, we study the methanol metabolism of Desulfotomaculum kuznetsovii strain 17 T , isolated from a 3000-m deep geothermal water reservoir. We use proteomics to analyze cells grown with methanol and sulfate in the presence and absence of cobalt and vitamin B12. The results indicate the presence of two methanol-degrading pathways in D. kuznetsovii, a cobalt-dependent methanol methyltransferase and a cobalt-independent methanol dehydrogenase, which is further confirmed by stable isotope fractionation. This is the first report of a microorganism utilizing two distinct methanol conversion pathways. We hypothesize that this gives D. kuznetsovii a competitive advantage in its natural environment.

  17. Systematic unraveling of the unsolved pathway of nicotine degradation in Pseudomonas.

    Directory of Open Access Journals (Sweden)

    Hongzhi Tang

    2013-10-01

    Full Text Available Microorganisms such as Pseudomonas putida play important roles in the mineralization of organic wastes and toxic compounds. To comprehensively and accurately elucidate key processes of nicotine degradation in Pseudomonas putida, we measured differential protein abundance levels with MS-based spectral counting in P. putida S16 grown on nicotine or glycerol, a non-repressive carbon source. In silico analyses highlighted significant clustering of proteins involved in a functional pathway in nicotine degradation. The transcriptional regulation of differentially expressed genes was analyzed by using quantitative reverse transcription-PCR. We observed the following key results: (i The proteomes, containing 1,292 observed proteins, provide a detailed view of enzymes involved in nicotine metabolism. These proteins could be assigned to the functional groups of transport, detoxification, and amino acid metabolism. There were significant differences in the cytosolic protein patterns of cells growing in a nicotine medium and those in a glycerol medium. (ii The key step in the conversion of 3-succinoylpyridine to 6-hydroxy-3-succinoylpyridine was catalyzed by a multi-enzyme reaction consisting of a molybdopeterin binding oxidase (spmA, molybdopterin dehydrogenase (spmB, and a (2Fe-2S-binding ferredoxin (spmC with molybdenum molybdopterin cytosine dinucleotide as a cofactor. (iii The gene of a novel nicotine oxidoreductase (nicA2 was cloned, and the recombinant protein was characterized. The proteins and functional pathway identified in the current study represent attractive targets for degradation of environmental toxic compounds.

  18. Genetic immunization based on the ubiquitin-fusion degradation pathway against Trypanosoma cruzi

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Bin [Department of Microbiology and Immunology, Faculty of Medicine, Fukuoka University, 7-45-1 Nanakuma, Jonan-ku, Fukuoka 814-0180 (Japan); Department of Parasitology, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582 (Japan); Hiromatsu, Kenji, E-mail: khiromatsu@fukuoka-u.ac.jp [Department of Microbiology and Immunology, Faculty of Medicine, Fukuoka University, 7-45-1 Nanakuma, Jonan-ku, Fukuoka 814-0180 (Japan); Hisaeda, Hajime; Duan, Xuefeng; Imai, Takashi [Department of Parasitology, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582 (Japan); Murata, Shigeo; Tanaka, Keiji [Department of Molecular Oncology, The Tokyo Metropolitan Institute of Medical Science, Tokyo 113-8613 (Japan); Himeno, Kunisuke [Department of Parasitology, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582 (Japan)

    2010-02-12

    Cytotoxic CD8{sup +} T cells are particularly important to the development of protective immunity against the intracellular protozoan parasite, Trypanosoma cruzi, the etiological agent of Chagas disease. We have developed a new effective strategy of genetic immunization by activating CD8{sup +} T cells through the ubiquitin-fusion degradation (UFD) pathway. We constructed expression plasmids encoding the amastigote surface protein-2 (ASP-2) of T. cruzi. To induce the UFD pathway, a chimeric gene encoding ubiquitin fused to ASP-2 (pUB-ASP-2) was constructed. Mice immunized with pUB-ASP-2 presented lower parasitemia and longer survival period, compared with mice immunized with pASP-2 alone. Depletion of CD8{sup +} T cells abolished protection against T. cruzi in mice immunized with pUB-ASP-2 while depletion of CD4{sup +} T cells did not influence the effective immunity. Mice deficient in LMP2 or LMP7, subunits of immunoproteasomes, were not able to develop protective immunity induced. These results suggest that ubiquitin-fused antigens expressed in antigen-presenting cells were effectively degraded via the UFD pathway, and subsequently activated CD8{sup +} T cells. Consequently, immunization with pUB-ASP-2 was able to induce potent protective immunity against infection of T. cruzi.

  19. Titanium dioxide-mediated heterogeneous photocatalytic degradation of terbufos: Parameter study and reaction pathways

    International Nuclear Information System (INIS)

    Wu, R.-J.; Chen, C.-C.; Chen, M.-H.; Lu, C.-S.

    2009-01-01

    The photocatalytic degradation of terbufos in aqueous suspensions was investigated by using titanium dioxide (TiO 2 ) as a photocatalyst. About 99% of terbufos was degraded after UV irradiation for 90 min. Factors such as pH of the system, TiO 2 dosage, and presence of anions were found to influence the degradation rate. Photodegradation of terbufos by TiO 2 /UV exhibited pseudo-first-order reaction kinetics, and a reaction quantum yield of 0.289. The electrical energy consumption per order of magnitude for photocatalytic degradation of terbufos was calculated and showed that a moderated efficiency (E EO = 71 kWh/(m 3 order)) was obtained in TiO 2 /UV process. To obtain a better understanding of the mechanistic details of this TiO 2 -assisted photodegradation of terbufos with UV irradiation, the intermediates of the processes were separated, identified, and characterized by the solid-phase microextraction (SPME) and gas chromatography/mass spectrometry (GC/MS) technique. The probable photodegradation pathways were proposed and discussed

  20. Bacterial community structure and predicted alginate metabolic pathway in an alginate-degrading bacterial consortium.

    Science.gov (United States)

    Kita, Akihisa; Miura, Toyokazu; Kawata, Satoshi; Yamaguchi, Takeshi; Okamura, Yoshiko; Aki, Tsunehiro; Matsumura, Yukihiko; Tajima, Takahisa; Kato, Junichi; Nishio, Naomichi; Nakashimada, Yutaka

    2016-03-01

    Methane fermentation is one of the effective approaches for utilization of brown algae; however, this process is limited by the microbial capability to degrade alginate, a main polysaccharide found in these algae. Despite its potential, little is known about anaerobic microbial degradation of alginate. Here we constructed a bacterial consortium able to anaerobically degrade alginate. Taxonomic classification of 16S rRNA gene, based on high-throughput sequencing data, revealed that this consortium included two dominant strains, designated HUA-1 and HUA-2; these strains were related to Clostridiaceae bacterium SK082 (99%) and Dysgonomonas capnocytophagoides (95%), respectively. Alginate lyase activity and metagenomic analyses, based on high-throughput sequencing data, revealed that this bacterial consortium possessed putative genes related to a predicted alginate metabolic pathway. However, HUA-1 and 2 did not grow on agar medium with alginate by using roll-tube method, suggesting the existence of bacterial interactions like symbiosis for anaerobic alginate degradation. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  1. Chemical modification and degradation of atrazine in Medicago sativa through multiple pathways.

    Science.gov (United States)

    Zhang, Jing Jing; Lu, Yi Chen; Yang, Hong

    2014-10-08

    Atrazine is a member of the triazine herbicide family intensively used to control weeds for crop production. In this study, atrazine residues and its degraded products in alfalfa (Medicago sativa) were characterized using UPLC-TOF-MS/MS. Most of atrazine absorbed in plants was found as chemically modified derivatives like deisopropylated atrazine (DIA), dehydrogenated atrazine (DHA), or methylated atrazine (MEA), and some atrazine derivatives were conjugated through different functional groups such as sugar, glutathione, and amino acids. Interestingly, the specific conjugates DHA+hGSH (homoglutathione) and MEA-HCl+hGSH in alfalfa were detected. These results suggest that atrazine in alfalfa can be degraded through different pathways. The increased activities of glycosyltransferase and glutathione S-transferase were determined to support the atrazine degradation models. The outcome of the work uncovered the detailed mechanism for the residual atrazine accumulation and degradation in alfalfa and will help to evaluate whether the crop is suitable to be cultivated in the atrazine-polluted soil.

  2. Insulin-degrading enzyme is exported via an unconventional protein secretion pathway

    Directory of Open Access Journals (Sweden)

    Leissring Malcolm A

    2009-01-01

    Full Text Available Abstract Insulin-degrading enzyme (IDE is a ubiquitously expressed zinc-metalloprotease that degrades several pathophysiologically significant extracellular substrates, including insulin and the amyloid β-protein (Aβ, and accumulating evidence suggests that IDE dysfunction may be operative in both type 2 diabetes mellitus and Alzheimer disease (AD. Although IDE is well known to be secreted by a variety of cell types, the underlying trafficking pathway(s remain poorly understood. To address this topic, we investigated the effects of known inhibitors or stimulators of protein secretion on the secretion of IDE from murine hepatocytes and HeLa cells. IDE secretion was found to be unaffected by the classical secretion inhibitors brefeldin A (BFA, monensin, or nocodazole, treatments that readily inhibited the secretion of α1-antitrypsin (AAT overexpressed in the same cells. Using a novel cell-based Aβ-degradation assay, we show further that IDE secretion was similarly unaffected by multiple stimulators of protein secretion, including glyburide and 3'-O-(4-benzoylbenzoyl-ATP (Bz-ATP. The calcium ionophore, A23187, increased extracellular IDE activity, but only under conditions that also elicited cytotoxicity. Our results provide the first biochemical evidence that IDE export is not dependent upon the classical secretion pathway, thereby identifying IDE as a novel member of the select class of unconventionally secreted proteins. Further elucidation of the mechanisms underlying IDE secretion, which would be facilitated by the assays described herein, promises to uncover processes that might be defective in disease or manipulated for therapeutic benefit.

  3. Electrochemical treatment of trypan blue synthetic wastewater and its degradation pathway

    Directory of Open Access Journals (Sweden)

    ANANTHA N. SUBBA RAO

    2013-11-01

    Full Text Available The trypan blue (TB dye synthetic wastewater was treated in presence of chloride ions by electrochemical method. The effect of current density, pH, initial concentration of dye and supporting electrolyte on color and COD removal were investigated. The UV-Vis ab­sorption intensity, chemical oxygen demand (COD, cyclic voltammetry (CV, Fourier transform- infrared spectroscopy (FT-IR, gas chromatography – mass spectrometry (GC-MS analysis were conducted to investigate the kinetics and degradation pathway of TB dye.

  4. Electrochemical carbamazepine degradation: Effect of the generated active chlorine, transformation pathways and toxicity.

    Science.gov (United States)

    García-Espinoza, Josué Daniel; Mijaylova-Nacheva, Petia; Avilés-Flores, Martha

    2018-02-01

    Carbamazepine (CBZ) is a biorecalcitrant pharmaceutical compound frequently detected in wastewater and water bodies which has numerous negative effects on living organisms. In this investigation the effect of electrocatalytically generated active chlorine on CBZ degradation was studied using Nb/BDD or Ti/IrO 2 anodes. Subsequently, a response surface methodology based on a factorial plan and central composite design was carried out to determine the contribution of individual factors and to obtain the optimal experimental parameters for CBZ abatement. Electric current and treatment time were found to be the pivotal parameters influencing the degradation efficiency with respective contributions of 45.19% and 35.44%. The anode material had lower influence on the response, however, using an Nb/BDD anode, the oxidation was more effective due to the increased production of OH radicals as well as HClO, Cl and ClO - species. Considering CBZ degradation and energetic consumption, the percentage of degraded CBZ was 88.70 ± 0.35% consuming 1.07 kWh m -3 (at 1.0 A, NaCl concentration of 14 mM after 12.45 min, using Nb/BDD anode). First order kinetic constant (k) value of 0.189 min -1 was obtained at optimal conditions when demineralized water was used for the NaCl supporting electrolyte, while k was lower when tap water or treated wastewaters were used for this purpose. Oxidation of CBZ yielded six aromatic intermediates, identified by gas chromatography - mass spectrometry technique and degradation pathways were proposed. The performed acute toxicity tests indicated an increase during the treatment, which was demonstrated to be mainly attributed to the remnant active chlorine. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Molecular and biochemical characterization of the tetralin degradation pathway in Rhodococcus sp. strain TFB

    Science.gov (United States)

    Tomás‐Gallardo, Laura; Santero, Eduardo; Camafeita, Emilio; Calvo, Enrique; Schlömann, Michael; Floriano, Belén

    2009-01-01

    Summary The tetralin biodegradation pathway in Rhodococcus sp. strain TFB, a Gram‐positive bacterium resistant to genetic manipulation, was characterized using a proteomic approach. Relative protein expression in cell free extracts from tetralin‐ and glucose‐grown cells was compared using the 2D‐DIGE technique. Identification of proteins specifically expressed in tetralin‐grown cells was used to characterize a complete set of genes involved in tetralin degradation by reverse genetics. We propose a tetralin degradation pathway analogous to that described for Sphingomonas macrogolitabida strain TFA. TFB thn genes are organized into three operons; two contain all of the structural genes and are transcribed in the same direction, while the third operon, thnST, is transcribed in the opposite direction and encodes a two‐component regulatory system, whose transcription is higher in tetralin‐grown cells. In addition to tetralin induction, TFB thn structural genes are subject to glucose repression. Primer extension assays and translational thnA1::gfp and thnS::gfp fusions were used to characterize putative promoter regions. A mutational analysis of the thnA1 promoter region allowed us to define nucleotides within the cis regulatory elements that are important for the control of thn gene expression. PMID:21261920

  6. Genomic organisation, activity and distribution analysis of the microbial putrescine oxidase degradation pathway.

    Science.gov (United States)

    Foster, Alexander; Barnes, Nicole; Speight, Robert; Keane, Mark A

    2013-10-01

    The catalytic action of putrescine specific amine oxidases acting in tandem with 4-aminobutyraldehyde dehydrogenase is explored as a degradative pathway in Rhodococcus opacus. By limiting the nitrogen source, increased catalytic activity was induced leading to a coordinated response in the oxidative deamination of putrescine to 4-aminobutyraldehyde and subsequent dehydrogenation to 4-aminobutyrate. Isolating the dehydrogenase by ion exchange chromatography and gel filtration revealed that the enzyme acts principally on linear aliphatic aldehydes possessing an amino moiety. Michaelis-Menten kinetic analysis delivered a Michaelis constant (K(M)=0.014 mM) and maximum rate (Vmax=11.2 μmol/min/mg) for the conversion of 4-aminobutyraldehyde to 4-aminobutyrate. The dehydrogenase identified by MALDI-TOF mass spectrometric analysis (E value=0.031, 23% coverage) belongs to a functionally related genomic cluster that includes the amine oxidase, suggesting their association in a directed cell response. Key regulatory, stress and transport encoding genes have been identified, along with candidate dehydrogenases and transaminases for the further conversion of 4-aminobutyrate to succinate. Genomic analysis has revealed highly similar metabolic gene clustering among members of Actinobacteria, providing insight into putrescine degradation notably among Micrococcaceae, Rhodococci and Corynebacterium by a pathway that was previously uncharacterised in bacteria. Copyright © 2013 Elsevier GmbH. All rights reserved.

  7. Hexachlorophene inhibits Wnt/beta-catenin pathway by promoting Siah-mediated beta-catenin degradation.

    Science.gov (United States)

    Park, Seoyoung; Gwak, Jungsug; Cho, Munju; Song, Taeyun; Won, Jaejoon; Kim, Dong-Eun; Shin, Jae-Gook; Oh, Sangtaek

    2006-09-01

    Aberrant activation of Wnt/beta-catenin signaling and subsequent up-regulation of beta-catenin response transcription (CRT) is a critical event in the development of human colon cancer. Thus, Wnt/beta-catenin signaling is an attractive target for the development of anticancer therapeutics. In this study, we identified hexachlorophene as an inhibitor of Wnt/beta-catenin signaling from cell-based small-molecule screening. Hexachlorophene antagonized CRT that was stimulated by Wnt3a-conditioned medium by promoting the degradation of beta-catenin. This degradation pathway is Siah-1 and adenomatous polyposis colidependent, but glycogen synthase kinase-3beta and F-box beta-transducin repeat-containing protein-independent. In addition, hexachlorophene represses the expression of cyclin D1, which is a known beta-catenin target gene, and inhibits the growth of colon cancer cells. Our findings suggest that hexachlorophene attenuates Wnt/beta-catenin signaling through the Siah-1-mediated beta-catenin degradation.

  8. Alteration of Dynein Function Affects α-Synuclein Degradation via the Autophagosome-Lysosome Pathway

    Directory of Open Access Journals (Sweden)

    Da Li

    2013-12-01

    Full Text Available Growing evidence suggests that dynein dysfunction may be implicated in the pathogenesis of neurodegeneration. It plays a central role in aggresome formation, the delivery of autophagosome to lysosome for fusion and degradation, which is a pro-survival mechanism essential for the bulk degradation of misfolded proteins and damaged organells. Previous studies reported that dynein dysfuntion was associated with aberrant aggregation of α-synuclein, which is a major component of inclusion bodies in Parkinson’s disease (PD. However, it remains unclear what roles dynein plays in α-synuclein degradation. Our study demonstrated a decrease of dynein expression in neurotoxin-induced PD models in vitro and in vivo, accompanied by an increase of α-synuclein protein level. Dynein down-regulation induced by siRNA resulted in a prolonged half-life of α-synuclein and its over-accumulation in A53T overexpressing PC12 cells. Dynein knockdown also prompted the increase of microtubule-associated protein 1 light chain 3 (LC3-II and sequestosome 1 (SQSTM1, p62 expression, and the accumulation of autophagic vacuoles. Moreover, dynein suppression impaired the autophagosome fusion with lysosome. In summary, our findings indicate that dynein is critical for the clearance of aberrant α-synuclein via autophagosome-lysosome pathway.

  9. Unfolded protein response and activated degradative pathways regulation in GNE myopathy.

    Directory of Open Access Journals (Sweden)

    Honghao Li

    Full Text Available Although intracellular beta amyloid (Aβ accumulation is known as an early upstream event in the degenerative course of UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE myopathy, the process by which Aβdeposits initiate various degradative pathways, and their relationship have not been fully clarified. We studied the possible secondary responses after amyloid beta precursor protein (AβPP deposition including unfolded protein response (UPR, ubiquitin proteasome system (UPS activation and its correlation with autophagy system. Eight GNE myopathy patients and five individuals with normal muscle morphology were included in this study. We performed immunofluorescence and immunoblotting to investigate the expression of AβPP, phosphorylated tau (p-tau and endoplasmic reticulum molecular chaperones. Proteasome activities were measured by cleavage of fluorogenic substrates. The expression of proteasome subunits and linkers between proteasomal and autophagy systems were also evaluated by immunoblotting and relative quantitative real-time RT-PCR. Four molecular chaperones, glucose-regulated protein 94 (GRP94, glucose-regulated protein 78 (GRP78, calreticulin and calnexin and valosin containing protein (VCP were highly expressed in GNE myopathy. 20S proteasome subunits, three main proteasome proteolytic activities, and the factors linking UPS and autophagy system were also increased. Our study suggests that AβPP deposition results in endoplasmic reticulum stress (ERS and highly expressed VCP deliver unfolded proteins from endoplasmic reticulum to proteosomal system which is activated in endoplasmic reticulum associated degradation (ERAD in GNE myopathy. Excessive ubiquitinated unfolded proteins are exported by proteins that connect UPS and autophagy to autophagy system, which is activated as an alternative pathway for degradation.

  10. Identification of genes and pathways related to phenol degradation in metagenomic libraries from petroleum refinery wastewater.

    Directory of Open Access Journals (Sweden)

    Cynthia C Silva

    Full Text Available Two fosmid libraries, totaling 13,200 clones, were obtained from bioreactor sludge of petroleum refinery wastewater treatment system. The library screening based on PCR and biological activity assays revealed more than 400 positive clones for phenol degradation. From these, 100 clones were randomly selected for pyrosequencing in order to evaluate the genetic potential of the microorganisms present in wastewater treatment plant for biodegradation, focusing mainly on novel genes and pathways of phenol and aromatic compound degradation. The sequence analysis of selected clones yielded 129,635 reads at an estimated 17-fold coverage. The phylogenetic analysis showed Burkholderiales and Rhodocyclales as the most abundant orders among the selected fosmid clones. The MG-RAST analysis revealed a broad metabolic profile with important functions for wastewater treatment, including metabolism of aromatic compounds, nitrogen, sulphur and phosphorus. The predicted 2,276 proteins included phenol hydroxylases and cathecol 2,3- dioxygenases, involved in the catabolism of aromatic compounds, such as phenol, byphenol, benzoate and phenylpropanoid. The sequencing of one fosmid insert of 33 kb unraveled the gene that permitted the host, Escherichia coli EPI300, to grow in the presence of aromatic compounds. Additionally, the comparison of the whole fosmid sequence against bacterial genomes deposited in GenBank showed that about 90% of sequence showed no identity to known sequences of Proteobacteria deposited in the NCBI database. This study surveyed the functional potential of fosmid clones for aromatic compound degradation and contributed to our knowledge of the biodegradative capacity and pathways of microbial assemblages present in refinery wastewater treatment system.

  11. Method of removing polychlorinated biphenyl from oil

    Science.gov (United States)

    Cook, Gus T.; Holshouser, Stephen K.; Coleman, Richard M.; Harless, Charles E.; Whinnery, III, Walter N.

    1983-01-01

    Polychlorinated biphenyls are removed from oil by extracting the biphenyls into methanol. The mixture of methanol and extracted biphenyls is distilled to separate methanol therefrom, and the methanol is recycled for further use in extraction of biphenyls from oil.

  12. Transfer of the high GC cyclohexane carboxylate degradation pathway from Rhodopseudomonas palustris to Escherichia coli for production of biotin

    Science.gov (United States)

    Bernstein, Jeffrey R.; Bulter, Thomas; Liao, James C.

    2008-01-01

    This work demonstrates the transfer of the five gene cyclohexane carboxylate (CHC) degradation pathway from the high GC alphaproteobacterium Rhodopseudomonas palustris to Escherichia coli, a gammaproteobacterium. The degradation product of this pathway is pimeloyl-CoA, a key metabolite in E. coli's biotin biosynthetic pathway. This pathway is useful for biotin overproduction in E. coli, however, the expression of GC-rich genes is troublesome in this host. When the native R. palustris CHC degradation pathway is transferred to a ΔbioH pimeloyl-CoA auxotroph of E. coli, it is unable to complement growth in the presence of CHC. To overcome this expression problem we redesigned the operon with decreased GC content and removed stretches of high GC intergenic DNA which comprise the 5' untranslated region of each gene, replacing these features with shorter low GC sequences. We show this synthetic construct enables growth of the ΔbioH strain in the presence of CHC. When the synthetic degradation pathway is overexpressed in conjunction with the downstream genes for biotin biosynthesis, we measured significant accumulation of biotin in the growth medium, showing that the pathway transfer is successfully integrated with the host metabolism. PMID:18396082

  13. Transfer of the high-GC cyclohexane carboxylate degradation pathway from Rhodopseudomonas palustris to Escherichia coli for production of biotin.

    Science.gov (United States)

    Bernstein, Jeffrey R; Bulter, Thomas; Liao, James C

    2008-01-01

    This work demonstrates the transfer of the five-gene cyclohexane carboxylate (CHC) degradation pathway from the high-GC alphaproteobacterium Rhodopseudomonas palustris to Escherichia coli, a gammaproteobacterium. The degradation product of this pathway is pimeloyl-CoA, a key metabolite in E. coli's biotin biosynthetic pathway. This pathway is useful for biotin overproduction in E. coli; however, the expression of GC-rich genes is troublesome in this host. When the native R. palustris CHC degradation pathway is transferred to a DeltabioH pimeloyl-CoA auxotroph of E. coli, it is unable to complement growth in the presence of CHC. To overcome this expression problem we redesigned the operon with decreased GC content and removed stretches of high-GC intergenic DNA which comprise the 5' untranslated region of each gene, replacing these features with shorter low-GC sequences. We show this synthetic construct enables growth of the DeltabioH strain in the presence of CHC. When the synthetic degradation pathway is overexpressed in conjunction with the downstream genes for biotin biosynthesis, we measured significant accumulation of biotin in the growth medium, showing that the pathway transfer is successfully integrated with the host metabolism.

  14. Photodegradation of gemfibrozil in aqueous solution under UV irradiation: kinetics, mechanism, toxicity, and degradation pathways.

    Science.gov (United States)

    Ma, Jingshuai; Lv, Wenying; Chen, Ping; Lu, Yida; Wang, Fengliang; Li, Fuhua; Yao, Kun; Liu, Guoguang

    2016-07-01

    The lipid regulator gemfibrozil (GEM) has been reported to be persistent in conventional wastewater treatment plants. This study investigated the photolytic behavior, toxicity of intermediate products, and degradation pathways of GEM in aqueous solutions under UV irradiation. The results demonstrated that the photodegradation of GEM followed pseudo-first-order kinetics, and the pseudo-first-order rate constant was decreased markedly with increasing initial concentrations of GEM and initial pH. The photodegradation of GEM included direct photolysis via (3)GEM(*) and self-sensitization via ROS, where the contribution rates of degradation were 0.52, 90.05, and 8.38 % for ·OH, (1)O2, and (3)GEM(*), respectively. Singlet oxygen ((1)O2) was evidenced by the molecular probe compound, furfuryl alcohol (FFA), and was identified as the primary reactive species in the photolytic process. The steady-state concentrations of (1)O2 increased from (0.324 ± 0.014) × 10(-12) to (1.021 ± 0.040) × 10(-12) mol L(-1), as the initial concentrations of GEM were increased from 5 to 20 mg L(-1). The second-order rate constant for the reaction of GEM with (1)O2 was calculated to be 2.55 × 10(6) M(-1) s(-1). The primary transformation products were identified using HPLC-MS/MS, and possible photodegradation pathways were proposed by hydroxylation, aldehydes reactions, as well as the cleavage of ether side chains. The toxicity of phototransformation product evaluation revealed that photolysis potentially provides a critical pathway for GEM toxicity reduction in potable water and wastewater treatment facilities.

  15. The metabolic pathway of metamifop degradation by consortium ME-1 and its bacterial community structure.

    Science.gov (United States)

    Dong, Weiliang; Liu, Kuan; Wang, Fei; Xin, Fengxue; Zhang, Wenming; Zhang, Min; Wu, Hao; Ma, Jiangfeng; Jiang, Min

    2017-06-01

    Metamifop is universally used in agriculture as a post-emergence aryloxyphenoxy propionate herbicide (AOPP), however its microbial degradation mechanism remains unclear. Consortium ME-1 isolated from AOPP-contaminated soil can degrade metamifop completely after 6 days and utilize it as the carbon source for bacterial growth. Meanwhile, consortium ME-1 possessed the ability to degrade metamifop stably under a wide range of pH (6.0-10.0) or temperature (20-42 °C). HPLC-MS analysis shows that N-(2-fluorophenyl)-2-(4-hydroxyphenoxy)-N-methyl propionamide, 2-(4-hydroxyphenoxy)-propionic acid, 6-chloro-2-benzoxazolinone and N-methyl-2-fluoroaniline, were detected and identified as four intermediate metabolites. Based on the metabolites identified, a putative metabolic pathway of metamifop was proposed for the first time. In addition, the consortium ME-1 was also able to transform or degrade other AOPP such as fenoxaprop-p-ethyl, clodinafop-propargyl, quizalofop-p-ethyl and cyhalofop-butyl. Moreover, the community structure of ME-1 with lower microbial diversity compared with the initial soil sample was investigated by high throughput sequencing. β-Proteobacteria and Sphingobacteria were the largest class with sequence percentages of 46.6% and 27.55% at the class level. In addition, 50 genera were classified in consortium ME-1, of which Methylobacillus, Sphingobacterium, Bordetella and Flavobacterium were the dominant genera with sequence percentages of 25.79, 25.61, 14.68 and 9.55%, respectively.

  16. Further characterization of o-nitrobenzaldehyde degrading bacterium Pseudomonas sp. ONBA-17 and deduction on its metabolic pathway.

    Science.gov (United States)

    Yu, Fang-Bo; Li, Xiao-Dan; Ali, Shinawar Waseem; Shan, Sheng-Dao; Luo, Lin-Ping; Guan, Li-Bo

    2014-01-01

    A previously reported o-nitrobenzaldehyde (ONBA) degrading bacterium Pseudomonas sp. ONBA-17 was further identified and characterized. Based on results of DNA base composition and DNA-DNA hybridization, the strain was identified as P. putida. Its degradation effect enhanced with increase of inoculum amount and no lag phase was observed. Higher removal rate was achieved under shaking conditions. All tested ONBA with different initial concentrations could be completely degraded within 5 d. In addition, degradative enzyme(s) involved was confirmed as intra-cellular distributed and constitutively expressed. Effects of different compounds on relative activity of degradative enzyme(s) within cell-free extract were also evaluated. Finally, 2-nitrobenzoic acid and 2, 3-dihydroxybenzoic acid were detected as metabolites of ONBA degradation by P. putida ONBA-17, and relevant metabolic pathway was preliminary proposed. This study might help with future research in better understanding of nitroaromatics biodegradation.

  17. Removal and Degradation Pathways of Sulfamethoxazole Present in Synthetic Municipal Wastewater via an Anaerobic Membrane Bioreactor

    KAUST Repository

    Sanchez Huerta, Claudia

    2016-05-01

    The current global water crisis in addition to continues contamination of natural water bodies with harmful organic micropollutants (OMPs) have driven the development of new water treatment technologies that allow the efficient removal of such compounds. Among a long list of OMPs, antibiotics are considered as top priority pollutants to be treated due to their great resistance to biological treatments and their potential to develop bacterial resistance. Different approaches, such as membrane-based and advance oxidation processes have been proposed to alleviate or minimize antibiotics discharge into aquatic environments. However most of these processes are costly and generate either matrices with high concentration of OMPs or intermediate products with potentially greater toxicity or persistence. Therefore, this thesis proposes the study of an anaerobic membrane bioreactor (AnMBR) for the treatment of synthetic municipal wastewater containing sulfamethoxazole (SMX), a world widely used antibiotic. Besides the general evaluation of AnMBR performance in the COD removal and biogas production, this research mainly focuses on the SMX removal and its degradation pathway. Thus 5 SMX quantification was performed through solid phase extraction-liquid chromatography/mass spectrometry and the identification of its transformation products (TPs) was assessed by gas chromatography/mass spectrometry technique. The results achieved showed that, working under optimal conditions (35°C, pH 7 and ORP around -380 to -420 mV) and after a biomass adaptation period (maintaining 0.85 VSS/TSS ratio), the AnMBR process provided over 95% COD removal and 95-98% SMX removal, while allowing stable biogas composition and methane production (≈130 mL CH4/g CODremoved). Kinetic analysis through a batch test showed that after 24 h of biological reaction, AnMBR process achieved around 94% SMX removal, indicating a first order kinetic reaction with K= 0.119, which highlights the high degradation

  18. Physiology of deletion mutants in the anaerobic β-myrcene degradation pathway in Castellaniella defragrans

    Directory of Open Access Journals (Sweden)

    Lüddeke Frauke

    2012-09-01

    Full Text Available Abstract Background Monoterpenes present a large and versatile group of unsaturated hydrocarbons of plant origin with widespread use in the fragrance as well as food industry. The anaerobic β-myrcene degradation pathway in Castellaniella defragrans strain 65Phen differs from well known aerobic, monooxygenase-containing pathways. The initial enzyme linalool dehydratase-isomerase ldi/LDI catalyzes the hydration of β-myrcene to (S-(+-linalool and its isomerization to geraniol. A high-affinity geraniol dehydrogenase geoA/GeDH and a geranial dehydrogenase geoB/GaDH contribute to the formation of geranic acid. A genetic system was for the first time applied for the betaproteobacterium to prove in vivo the relevance of the linalool dehydratase-isomerase and the geraniol dehydrogenase. In-frame deletion cassettes were introduced by conjugation and two homologous recombination events. Results Polar effects were absent in the in-frame deletion mutants C. defragrans Δldi and C. defragrans ΔgeoA. The physiological characterization of the strains demonstrated a requirement of the linalool dehydratase-isomerase for growth on acyclic monoterpenes, but not on cyclic monoterpenes. The deletion of geoA resulted in a phenotype with hampered growth rate on monoterpenes as sole carbon and energy source as well as reduced biomass yields. Enzyme assays revealed the presence of a second geraniol dehydrogenase. The deletion mutants were in trans complemented with the broad-host range expression vector pBBR1MCS-4ldi and pBBR1MCS-2geoA, restoring in both cases the wild type phenotype. Conclusions In-frame deletion mutants of genes in the anaerobic β-myrcene degradation revealed novel insights in the in vivo function. The deletion of a high-affinity geraniol dehydrogenase hampered, but did not preclude growth on monoterpenes. A second geraniol dehydrogenase activity was present that contributes to the β-myrcene degradation pathway. Growth on cyclic monoterpenes

  19. Carbon and chlorine isotope analysis to identify abiotic degradation pathways of 1,1,1-trichloroethane.

    Science.gov (United States)

    Palau, Jordi; Shouakar-Stash, Orfan; Hunkeler, Daniel

    2014-12-16

    This study investigates dual C-Cl isotope fractionation during 1,1,1-TCA transformation by heat-activated persulfate (PS), hydrolysis/dehydrohalogenation (HY/DH) and Fe(0). Compound-specific chlorine isotope analysis of 1,1,1-TCA was performed for the first time, and transformation-associated isotope fractionation ε bulk C and ε bulk Cl values were -4.0 ± 0.2‰ and no chlorine isotope fractionation with PS, -1.6 ± 0.2‰ and -4.7 ± 0.1‰ for HY/DH, -7.8 ± 0.4‰ and -5.2 ± 0.2‰ with Fe(0). Distinctly different dual isotope slopes (Δδ13C/Δδ37Cl): ∞ with PS, 0.33 ± 0.04 for HY/DH and 1.5 ± 0.1 with Fe(0) highlight the potential of this approach to identify abiotic degradation pathways of 1,1,1-TCA in the field. The trend observed with PS agreed with a C-H bond oxidation mechanism in the first reaction step. For HY/DH and Fe(0) pathways, different slopes were obtained although both pathways involve cleavage of a C-Cl bond in their initial reaction step. In contrast to the expected larger primary carbon isotope effects relative to chlorine for C-Cl bond cleavage, ε bulk C isotope effects. Therefore, different magnitude of secondary chlorine isotope effects could at least be partly responsible for the distinct slopes between HY/DH and Fe(0) pathways. Following this dual isotope approach, abiotic transformation processes can unambiguously be identified and quantified.

  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. Photocatalytic transformation of sixteen substituted phenylurea herbicides in aqueous semiconductor suspensions: Intermediates and degradation pathways

    Energy Technology Data Exchange (ETDEWEB)

    Fenoll, José, E-mail: jose.fenoll@carm.es [Departamento de Calidad y Garantía Alimentaria, Instituto Murciano de Investigación y Desarrollo Agrario y Alimentario (IMIDA), C/Mayor s/n, La Alberca, 30150 Murcia (Spain); Sabater, Paula [Departamento de Calidad y Garantía Alimentaria, Instituto Murciano de Investigación y Desarrollo Agrario y Alimentario (IMIDA), C/Mayor s/n, La Alberca, 30150 Murcia (Spain); Navarro, Gines; Pérez-Lucas, Gabriel; Navarro, Simón [Departamento de Química Agrícola, Geología y Edafología, Facultad de Química, Universidad de Murcia, Campus Universitario de Espinardo, 30100 Murcia (Spain)

    2013-01-15

    Highlights: ► Photocatalytic oxidation of phenylurea herbicides (PUHs) in water. ► The study was performed using ZnO and TiO{sub 2} under artificial light irradiation. ► PUHs were totally degraded using ZnO/Na{sub 2}S{sub 2}O{sub 8}, ZnO, TiO{sub 2}/Na{sub 2}S{sub 2}O{sub 8} and TiO{sub 2}. ► ZnO is the most efficient photocatalyst for the removal of these herbicides. ► 13 intermediates were identified and a mechanism of degradation has been proposed. -- Abstract: The photocatalytic degradation of sixteen substituted phenylurea herbicides (PUHs) in pure water has been studied using zinc oxide (ZnO) and titanium dioxide (TiO{sub 2}) as photocatalyst under artificial light irradiation. Photocatalytic experiments showed that the addition of these chalcogenide oxides in tandem with the oxidant (Na{sub 2}S{sub 2}O{sub 8}) strongly enhances the degradation rate of these compounds in comparison with those carried out with ZnO and TiO{sub 2} alone and photolytic tests. Comparison of catalysts showed that ZnO is the most efficient for the removal of such herbicides in optimal conditions and at constant volumetric rate of photon absorption in the photoreactor. Thus, the complete disappearance of all the studied compounds was achieved after 20 min of illumination in the ZnO/Na{sub 2}S{sub 2}O{sub 8} system. The main photocatalytic intermediates detected during the degradation of PUHs were identified. The probable photodegradation pathways were proposed and discussed. The main steps involved: N-demethylation of the N,N-dimethylurea-substituted compounds followed of N-demethylation and N-demethoxylation of the N-methoxy-N-methyl-substituted ureas and hydroxylation of aromatic rings and their aliphatic side-chains of both, parent compounds and intermediates.

  2. Photocatalytic degradation of metoprolol tartrate in suspensions of two TiO{sub 2}-based photocatalysts with different surface area. Identification of intermediates and proposal of degradation pathways

    Energy Technology Data Exchange (ETDEWEB)

    Abramovic, Biljana, E-mail: biljana.abramovic@dh.uns.ac.rs [Department of Chemistry, Biochemistry and Environmental Protection, Faculty of Sciences, University of Novi Sad, Trg D. Obradovica 3, 21000 Novi Sad (Serbia); Kler, Sanja, E-mail: sanja.kler@dh.uns.ac.rs [Department of Chemistry, Biochemistry and Environmental Protection, Faculty of Sciences, University of Novi Sad, Trg D. Obradovica 3, 21000 Novi Sad (Serbia); Sojic, Daniela, E-mail: daniela.sojic@dh.uns.ac.rs [Department of Chemistry, Biochemistry and Environmental Protection, Faculty of Sciences, University of Novi Sad, Trg D. Obradovica 3, 21000 Novi Sad (Serbia); Lausevic, Mila, E-mail: milal@tmf.bg.ac.rs [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11120 Belgrade (Serbia); Radovic, Tanja, E-mail: tradovic@tmf.bg.ac.rs [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11120 Belgrade (Serbia); Vione, Davide, E-mail: davide.vione@unito.it [Dipartimento di Chimica Analitica, Universita di Torino, Via Pietro Giuria 5, 10125 Torino (Italy)

    2011-12-30

    Highlights: Black-Right-Pointing-Pointer Kinetics and efficiency of photocatalytic degradation of the {beta}{sub 1}-blocker metoprolol tartrate (MET). Black-Right-Pointing-Pointer Two TiO{sub 2} specimens employed. Black-Right-Pointing-Pointer Faster degradation of MET, but slower mineralization, obtained with the TiO{sub 2} specimen having lower surface area. Black-Right-Pointing-Pointer Photocatalytic transformation pathways of MET including mineralization. - Abstract: This study investigates the efficiency of the photocatalytic degradation of metoprolol tartrate (MET), a widely used {beta}{sub 1}-blocker, in TiO{sub 2} suspensions of Wackherr's 'Oxyde de titane standard' and Degussa P25. The study encompasses transformation kinetics and efficiency, identification of intermediates and reaction pathways. In the investigated range of initial concentrations (0.01-0.1 mM), the photocatalytic degradation of MET in the first stage of the reaction followed approximately a pseudo-first order kinetics. The TiO{sub 2} Wackherr induced a significantly faster MET degradation compared to TiO{sub 2} Degussa P25 when relatively high substrate concentrations were used. By examining the effect of ethanol as a scavenger of hydroxyl radicals ({center_dot}OH), it was shown that the reaction with {center_dot}OH played the main role in the photocatalytic degradation of MET. After 240 min of irradiation the reaction intermediates were almost completely mineralized to CO{sub 2} and H{sub 2}O, while the nitrogen was predominantly present as NH{sub 4}{sup +}. Reaction intermediates were studied in detail and a number of them were identified using LC-MS/MS (ESI+), which allowed the proposal of a tentative pathway for the photocatalytic transformation of MET as a function of the TiO{sub 2} specimen.

  3. Unusual Starch Degradation Pathway via Cyclodextrins in the Hyperthermophilic Sulfate-Reducing Archaeon Archaeoglobus fulgidus Strain 7324▿

    Science.gov (United States)

    Labes, Antje; Schönheit, Peter

    2007-01-01

    The hyperthermophilic archaeon Archaeoglobus fulgidus strain 7324 has been shown to grow on starch and sulfate and thus represents the first sulfate reducer able to degrade polymeric sugars. The enzymes involved in starch degradation to glucose 6-phosphate were studied. In extracts of starch-grown cells the activities of the classical starch degradation enzymes, α-amylase and amylopullulanase, could not be detected. Instead, evidence is presented here that A. fulgidus utilizes an unusual pathway of starch degradation involving cyclodextrins as intermediates. The pathway comprises the combined action of an extracellular cyclodextrin glucanotransferase (CGTase) converting starch to cyclodextrins and the intracellular conversion of cyclodextrins to glucose 6-phosphate via cyclodextrinase (CDase), maltodextrin phosphorylase (Mal-P), and phosphoglucomutase (PGM). These enzymes, which are all induced after growth on starch, were characterized. CGTase catalyzed the conversion of starch to mainly β-cyclodextrin. The gene encoding CGTase was cloned and sequenced and showed highest similarity to a glucanotransferase from Thermococcus litoralis. After transport of the cyclodextrins into the cell by a transport system to be defined, these molecules are linearized via a CDase, catalyzing exclusively the ring opening of the cyclodextrins to the respective maltooligodextrins. These are degraded by a Mal-P to glucose 1-phosphate. Finally, PGM catalyzes the conversion of glucose 1-phosphate to glucose 6-phosphate, which is further degraded to pyruvate via the modified Embden-Meyerhof pathway. PMID:17921308

  4. Ubiquitin ligase Kf-1 is involved in the endoplasmic reticulum-associated degradation pathway.

    Science.gov (United States)

    Maruyama, Yoshiaki; Yamada, Misa; Takahashi, Kou; Yamada, Mitsuhiko

    2008-10-03

    Kf-1 was first identified as a gene showing enhanced expression in the cerebral cortex of a sporadic Alzheimer's disease patient. To date, however, the functional properties of Kf-1 protein remain unknown. In this study, immunohistochemical analysis showed that Kf-1 immunoreactivity was detected in rat hippocampus and cerebral cortex neurons. Interestingly, it was colocalized with endoplasmic reticulum (ER) marker. To investigate the specific function of Kf-1 protein, we generated Myc tagged wild type Kf-1 (Myc-Kf-1WT) and RING finger domain deletion mutant of Kf-1 (Myc-Kf-1DeltaR), and then transfected in HEK293 cells. Myc-Kf-1WT displayed a reticular pattern typical of ER localization, with large perinuclear aggregates and colocalized with ER marker, calnexin. Myc-Kf-1WT facilitated ubiquitination of endogenous proteins, whereas Myc-Kf-1DeltaR did not show ubiquitin ligase activity. In addition, we found that Kf-1 interacted with components of the ER-associated degradation (ERAD) pathway, including Derlin-1 and VCP. Taken together, these properties suggest that Kf-1 is an ER ubiquitin ligase involved in the ERAD pathway.

  5. Metabolic engineering of Escherichia coli for producing adipic acid through the reverse adipate-degradation pathway.

    Science.gov (United States)

    Zhao, Mei; Huang, Dixuan; Zhang, Xiaojuan; Koffas, Mattheos A G; Zhou, Jingwen; Deng, Yu

    2018-04-03

    Adipic acid is an important dicarboxylic acid mainly used for the production of nylon 6-6 fibers and resins. Previous studies focused on the biological production of adipic acid directly from different substrates, resulting in low yields and titers. In this study, a five-step reverse adipate-degradation pathway (RADP) identified in Thermobifida fusca has been reconstructed in Escherichia coli BL21 (DE3). The resulting strain (Mad136) produced 0.3gL -1 adipic acid with a 11.1% theoretical yield in shaken flasks, and we confirmed that the step catalyzed by 5-carboxy-2-pentenoyl-CoA reductase (Tfu_1647) as the rate-limiting step of the RADP. Overexpression of Tfu_1647 by pTrc99A carried by strain Mad146 produced with a 49.5% theoretical yield in shaken flasks. We further eliminated pathways for major metabolites competing for carbon flux by CRISPR/Cas9 and deleted the succinate-CoA ligase gene to promote accumulation of succinyl-CoA, which is the precursor for adipic acid synthesis. The final engineered strain Mad123146, which could achieve 93.1% of the theoretical yield in the shaken flask, was able to produce 68.0gL -1 adipic acid by fed-batch fermentation. To the best of our knowledge, these results constitute the highest adipic acid titer reported in E. coli. Copyright © 2018. Published by Elsevier Inc.

  6. Biodegradation of RDX and MNX with Rhodococcus sp. Strain DN22: New Insights into the Degradation Pathway

    Science.gov (United States)

    2010-11-15

    two distinctive pathways, (1) anaerobic reductive pathway involving sequential reduction of the sNsNO2 functional groups to give the corresponding...Abiotic transformation of hexahydro-1,3,5-trinitro-1,3,5-triazine by FeII bound to magnetite . Environ. Sci. Technol. 2004, 38, 1408–1414. (5...Hawari, J. RDX degradation using zero-valent iron nanoparticles . Environ. Sci. Technol. 2008, 42, 4364–4370. (13) Bhushan, B.; Halasz, A.; Spain, J. C

  7. Life and death of proteins after protease cleavage: protein degradation by the N-end rule pathway.

    Science.gov (United States)

    Dissmeyer, Nico; Rivas, Susana; Graciet, Emmanuelle

    2018-05-01

    Contents Summary 929 I. conservation and diversity of N-end rule pathways 929 II. Defensive functions of the N-end rule pathway in plants 930 III. Proteases and degradation by the N-end rule pathway 930 IV. New proteomics approaches for the identification of N-end rule substrates 932 V. Concluding remarks 932 Acknowledgements 934 References 934 SUMMARY: The N-end rule relates the stability of a protein to the identity of its N-terminal residue and some of its modifications. Since its discovery in the 1980s, the repertoire of N-terminal degradation signals has expanded, leading to a diversity of N-end rule pathways. Although some of these newly discovered N-end rule pathways remain largely unexplored in plants, recent discoveries have highlighted roles of N-end rule-mediated protein degradation in plant defense against pathogens and in cell proliferation during organ growth. Despite this progress, a bottleneck remains the proteome-wide identification of N-end rule substrates due to the prerequisite for endoproteolytic cleavage and technical limitations. Here, we discuss the recent diversification of N-end rule pathways and their newly discovered functions in plant defenses, stressing the role of proteases. We expect that novel proteomics techniques (N-terminomics) will be essential for substrate identification. We review these methods, their limitations and future developments. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  8. Degradation of nicosulfuron by a novel isolated bacterial strain Klebsiella sp. Y1: condition optimization, kinetics and degradation pathway.

    Science.gov (United States)

    Wang, Lin; Zhang, Xiaolin; Li, Yongmei

    2016-01-01

    A novel bacterial strain Klebsiella sp. Y1 was isolated from the soil of a constructed wetland, and it was identified based on the 16S rDNA sequence analysis. The co-metabolic degradation of nicosulfuron with glucose by Klebsiella sp. Y1 was investigated. The response surface methodology analysis indicated that the optimal pH and temperature were 7.0 and 35 °C, respectively, for the degradation of nicosulfuron. Under the optimal conditions, the degradation of nicosulfuron fitted Haldane kinetics model well. The removal of nicosulfuron was triggered by the acidification of glucose, which accelerated the hydrolysis of nicosulfuron. Then, the C-N bond of the sulfonylurea bridge was attacked and cleaved. Finally, the detected intermediate 2-amino-4,6-dimethoxypyrimidine was further biodegraded.

  9. Connecting Lignin-Degradation Pathway with Pre-Treatment Inhibitor Sensitivity of Cupriavidus necator

    Energy Technology Data Exchange (ETDEWEB)

    Wang, W. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Yang, S. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Hunsinger, G. B. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Pienkos, P. T. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Johnson, D. K. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2014-05-27

    In order to produce lignocellulosic biofuels economically, the complete release of monomers from the plant cell wall components, cellulose, hemicellulose, and lignin, through pre-treatment and hydrolysis (both enzymatic and chemical), and the efficient utilization of these monomers as carbon sources, is crucial. In addition, the identification and development of robust microbial biofuel production strains that can tolerate the toxic compounds generated during pre-treatment and hydrolysis is also essential. In this work, Cupriavidus necator was selected due to its capabilities for utilizing lignin monomers and producing polyhydroxylbutyrate (PHB), a bioplastic as well as an advanced biofuel intermediate. We characterized the growth kinetics of C. necator in pre-treated corn stover slurry as well as individually in the pre-sence of 11 potentially toxic compounds in the saccharified slurry. We found that C. necator was sensitive to the saccharified slurry produced from dilute acid pre-treated corn stover. Five out of 11 compounds within the slurry were characterized as toxic to C. necator, namely ammonium acetate, furfural, hydroxymethylfurfural (HMF), benzoic acid, and p-coumaric acid. Aldehydes (e.g., furfural and HMF) were more toxic than the acetate and the lignin degradation products benzoic acid and p-coumaric acid; furfural was identified as the most toxic compound. Although toxic to C. necator at high concentration, ammonium acetate, benzoic acid, and p-coumaric acid could be utilized by C. necator with a stimulating effect on C. necator growth. Consequently, the lignin degradation pathway of C. necator was reconstructed based on genomic information and literature. The efficient conversion of intermediate catechol to downstream products of cis,cis-muconate or 2-hydroxymuconate-6-semialdehyde may help improve the robustness of C. necator to benzoic acid and p-coumaric acid as well as improve PHB productivity.

  10. Connecting lignin-degradation pathway with pretreatment inhibitor sensitivity of Cupriavidus necator

    Directory of Open Access Journals (Sweden)

    Wei eWang

    2014-05-01

    Full Text Available To produce lignocellulosic biofuels economically, the complete release of monomers from the plant cell wall components, cellulose, hemicellulose and lignin, through pretreatment and hydrolysis (both enzymatic and chemical, and the efficient utilization of these monomers as carbon sources, is crucial. In addition, the identification and development of robust microbial biofuel production strains that can tolerate the toxic compounds generated during pretreatment and hydrolysis is also essential. In this work, Cupriavidus necator was selected due to its capabilities for utilizing lignin monomers and producing polyhydroxylbutyrate (PHB, a bioplastic as well as an advanced biofuel intermediate. We characterized the growth kinetics of C. necator in pretreated corn stover slurry as well as individually in the presence of 11 potentially toxic compounds in the saccharified slurry. We found that C. necator was sensitive to the saccharified slurry produced from dilute acid pretreated corn stover. Five out of 11 compounds within the slurry were characterized as toxic to C. necator, namely ammonium acetate, furfural, hydroxymethylfurfural (HMF, benzoic acid, and p-coumaric acid. Aldehydes (e.g., furfural and HMF were more toxic than the acetate and the lignin degradation products benzoic acid and p-coumaric acid; furfural was identified as the most toxic compound. Although toxic to C. necator at high concentration, ammonium acetate, benzoic acid, and p-coumaric acid could be utilized by C. necator with a stimulating effect on C. necator growth. Consequently, the lignin degradation pathway of C. necator was reconstructed based on genomic information and literature. The efficient conversion of intermediate catechol to downstream products of cis,cis-muconate or 2-hydroxymuconate-6-semialdehyde may help improve the robustness of C. necator to benzoic acid and p-coumaric acid as well as improve PHB productivity.

  11. The Whole Genome Sequence of Sphingobium chlorophenolicum L-1: Insights into the Evolution of the Pentachlorophenol Degradation Pathway

    Energy Technology Data Exchange (ETDEWEB)

    Copley, Shelley D. [University of Colorado; Rokicki, Joseph [University of Colorado; Turner, Pernilla [University of Colorado; Daligault, Hajnalka E. [Los Alamos National Laboratory (LANL); Nolan, Matt [U.S. Department of Energy, Joint Genome Institute; Land, Miriam L [ORNL

    2012-01-01

    Sphingobium chlorophenolicum Strain L-1 can mineralize the toxic pesticide pentachlorophenol (PCP). We have sequenced the genome of S. chlorophenolicum Strain L-1. The genome consists of a primary chromosome that encodes most of the genes for core processes, a secondary chromosome that encodes primarily genes that appear to be involved in environmental adaptation, and a small plasmid. The genes responsible for degradation of PCP are found on chromosome 2. We have compared the genomes of S. chlorophenolicum Strain L-1 and Sphingobium japonicum, a closely related Sphingomonad that degrades lindane. Our analysis suggests that the genes encoding the first three enzymes in the PCP degradation pathway were acquired via two different horizontal gene transfer events, and the genes encoding the final two enzymes in the pathway were acquired from the most recent common ancestor of these two bacteria.

  12. Role of the endoplasmic reticulum-associated degradation (ERAD) pathway in degradation of hepatitis C virus envelope proteins and production of virus particles.

    Science.gov (United States)

    Saeed, Mohsan; Suzuki, Ryosuke; Watanabe, Noriyuki; Masaki, Takahiro; Tomonaga, Mitsunori; Muhammad, Amir; Kato, Takanobu; Matsuura, Yoshiharu; Watanabe, Haruo; Wakita, Takaji; Suzuki, Tetsuro

    2011-10-28

    Viral infections frequently cause endoplasmic reticulum (ER) stress in host cells leading to stimulation of the ER-associated degradation (ERAD) pathway, which subsequently targets unassembled glycoproteins for ubiquitylation and proteasomal degradation. However, the role of the ERAD pathway in the viral life cycle is poorly defined. In this paper, we demonstrate that hepatitis C virus (HCV) infection activates the ERAD pathway, which in turn controls the fate of viral glycoproteins and modulates virus production. ERAD proteins, such as EDEM1 and EDEM3, were found to increase ubiquitylation of HCV envelope proteins via direct physical interaction. Knocking down of EDEM1 and EDEM3 increased the half-life of HCV E2, as well as virus production, whereas exogenous expression of these proteins reduced the production of infectious virus particles. Further investigation revealed that only EDEM1 and EDEM3 bind with SEL1L, an ER membrane adaptor protein involved in translocation of ERAD substrates from the ER to the cytoplasm. When HCV-infected cells were treated with kifunensine, a potent inhibitor of the ERAD pathway, the half-life of HCV E2 increased and so did virus production. Kifunensine inhibited the binding of EDEM1 and EDEM3 with SEL1L, thus blocking the ubiquitylation of HCV E2 protein. Chemical inhibition of the ERAD pathway neither affected production of the Japanese encephalitis virus (JEV) nor stability of the JEV envelope protein. A co-immunoprecipitation assay showed that EDEM orthologs do not bind with JEV envelope protein. These findings highlight the crucial role of the ERAD pathway in the life cycle of specific viruses.

  13. REGγ regulates ERα degradation via ubiquitin–proteasome pathway in breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Chai, Fan; Liang, Yan [Breast Disease Center, Southwest Hospital, Third Military Medical University, Chongqing 400038 (China); Bi, Jiong [Laboratory of General Surgery, First Affiliated Hospital, Sun Yet-sen University, Guangzhou 510080 (China); Chen, Li; Zhang, Fan [Breast Disease Center, Southwest Hospital, Third Military Medical University, Chongqing 400038 (China); Cui, Youhong [Institute of Pathology and Southwest Cancer Center, Southwest Hospital, Third Military Medical University, Chongqing 400038 (China); Jiang, Jun, E-mail: jcbd@medmail.com.cn [Breast Disease Center, Southwest Hospital, Third Military Medical University, Chongqing 400038 (China)

    2015-01-02

    Highlights: • High expression of REGγ is correlated with ERα status and poor clinical features. • Cell growth, mobility and invasion are significantly impaired by REGγ knockdown. • REGγ indirectly regulates ERα protein expression. - Abstract: REGγ is a proteasome coactivator which regulates proteolytic activity in eukaryotic cells. Abundant lines of evidence have showed that REGγ is over expressed in a number of human carcinomas. However, its precise role in the pathogenesis of cancer is still unclear. In this study, by examining 200 human breast cancer specimens, we demonstrated that REGγ was highly expressed in breast cancers, and the expression of REGγ was positively correlated with breast cancer patient estrogen receptor alpha (ERα) status. Moreover, the expression of REGγ was found positively associated with poor clinical features and low survival rates in ERα positive breast cancer patients. Further cell culture studies using MCF7 and BT474 breast cancer cell lines showed that cell proliferation, motility, and invasion capacities were decreased significantly by REGγ knockdown. Lastly, we demonstrated that REGγ indirectly regulates the degradation of ERα protein via ubiquitin–proteasome pathway. In conclusion, our findings provide the evidence that REGγ expression was positively correlated with ERα status and poor clinical prognosis in ERα positive breast cancer patients. As well, we disclose a new connection between the two molecules that are both highly expressed in most breast cancer cases.

  14. Acyclovir chemical kinetics with the discovery and identification of newly reported degradants and degradation pathways involving formaldehyde as a degradant and reactant intermediate.

    Science.gov (United States)

    Bejgum, Bhanu C; Johnson, Paul R; Stagner, William C

    2018-01-15

    The purpose of this research was to determine acyclovir (ACV) acidic degradation kinetics which is relevant to gastric retentive device product design. A stability-indicating method revealed two unknown degradation products which have been identified by mass spectrometry as ACV and guanine formaldehyde adducts. In addition to the formation of these adducts, a proposed degradation scheme identifies the formation of methyl acetal ethylene glycol, formaldehyde, ethylene glycol, and guanine as additional ACV degradation products. pH-rate profiles were explained by using a rate law which assumed acid-catalyzed hydrolysis of protonated and unprotonated ACV. The predicted and observed rate constants were in good agreement. Data-driven excipient selection recommendations were based on the chemical kinetic study results, degradation scheme, and pH-rate profiles. The average activation energy for the degradation reaction was determined to be 31.3±1.6kcal/mol. The predicted ACV t 90% at 37°C and pH 1.2 was calculated to be 7.2days. As a first approximation, this suggests that ACV gastric retentive devices designed to deliver drug for 7days should have acceptable drug product stability in the stomach. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Sirtuin 6 prevents matrix degradation through inhibition of the NF-κB pathway in intervertebral disc degeneration

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Liang [Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022 (China); Hu, Jia [Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022 (China); Weng, Yuxiong [Department of Hand Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022 (China); Jia, Jie [Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022 (China); Zhang, Yukun, E-mail: zhangyukuncom@126.com [Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022 (China)

    2017-03-15

    Intervertebral disc degeneration (IDD) is marked by imbalanced metabolism of the extracellular matrix (ECM) in the nucleus pulposus (NP) of intervertebral discs. This study aimed to determine whether sirtuin 6 (SIRT6), a member of the sirtuin family of nicotinamide adenine dinucleotide-dependent deacetylases, protects the NP from ECM degradation in IDD. Our study showed that expression of SIRT6 markedly decreased during IDD progression. Overexpression of wild-type SIRT6, but not a catalytically inactive mutant, prevented IL-1β-induced NP ECM degradation. SIRT6 depletion by RNA interference in NP cells caused ECM degradation. Moreover, SIRT6 physically interacted with nuclear factor-κB (NF-κB) catalytic subunit p65, transcriptional activity of which was significantly suppressed by SIRT6 overexpression. These results suggest that SIRT6 prevented NP ECM degradation in vitro via inhibiting NF-κB-dependent transcriptional activity and that this effect depended on its deacetylase activity. - Highlights: • SIRT6 expression is decreased in degenerative nucleus pulposus (NP) tissues. • SIRT6 overexpression lowers IL-1β-induced matrix degradation of NP. • SIRT6 inhibition induces matrix degradation of NP. • SIRT6 prevents matrix degradation of NP via the NF-κB signaling pathway.

  16. Heterogeneous electro-Fenton using modified iron-carbon as catalyst for 2,4-dichlorophenol degradation: influence factors, mechanism and degradation pathway.

    Science.gov (United States)

    Zhang, Chao; Zhou, Minghua; Ren, Gengbo; Yu, Xinmin; Ma, Liang; Yang, Jie; Yu, Fangke

    2015-03-01

    Modified iron-carbon with polytetrafluoroethylene (PTFE) was firstly investigated as heterogeneous electro-Fenton (EF) catalyst for 2,4-dichlorophenol (2,4-DCP) degradation in near neutral pH condition. The catalyst was characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), and the effects of some important operating parameters such as current intensity and pH on the 2,4-DCP degradation were investigated. After the catalyst modification with 20% PTFE, the degradation performance maintained well with much lower iron leaching, and at current intensity 100 mA, initial pH 6.7, catalyst loading 6 g/L, the degradation efficiency of 2,4-DCP could exceed 95% within 120 min treatment. Two-stage pseudo first-order kinetics of 2,4-DCP degradation was observed, including a slow anodic oxidation stage (first-stage) and much faster heterogeneous EF oxidation (second-stage), in which the automatic drop of pH in the first-stage initiated the Fe(2+) release from micro-electrolysis and thus benefited to the subsequent EF reaction. Aromatic intermediates such as 3,5-dichlorocatechol, 4,6-dichlororesorcinol and 2-chlorohydroquinone were detected by GC-MS. Oxalic acid, acetic acid, formic acid and Cl(-) were quantified by ion chromatograph. Based on these analysis as well as the detection of H₂O₂ and OH, a possible mechanism and degradation pathway for 2,4-DCP were proposed. This work demonstrated that such a heterogeneous EF using cheap modified Fe-C catalyst was promising for organic wastewater treatment in initial neutral pH condition. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Analysis of hydroxycinnamic acid degradation in Agrobacterium fabrum reveals a coenzyme A-dependent, beta-oxidative deacetylation pathway.

    Science.gov (United States)

    Campillo, Tony; Renoud, Sébastien; Kerzaon, Isabelle; Vial, Ludovic; Baude, Jessica; Gaillard, Vincent; Bellvert, Floriant; Chamignon, Cécile; Comte, Gilles; Nesme, Xavier; Lavire, Céline; Hommais, Florence

    2014-06-01

    The soil- and rhizosphere-inhabiting bacterium Agrobacterium fabrum (genomospecies G8 of the Agrobacterium tumefaciens species complex) is known to have species-specific genes involved in ferulic acid degradation. Here, we characterized, by genetic and analytical means, intermediates of degradation as feruloyl coenzyme A (feruloyl-CoA), 4-hydroxy-3-methoxyphenyl-β-hydroxypropionyl-CoA, 4-hydroxy-3-methoxyphenyl-β-ketopropionyl-CoA, vanillic acid, and protocatechuic acid. The genes atu1416, atu1417, and atu1420 have been experimentally shown to be necessary for the degradation of ferulic acid. Moreover, the genes atu1415 and atu1421 have been experimentally demonstrated to be essential for this degradation and are proposed to encode a phenylhydroxypropionyl-CoA dehydrogenase and a 4-hydroxy-3-methoxyphenyl-β-ketopropionic acid (HMPKP)-CoA β-keto-thiolase, respectively. We thus demonstrated that the A. fabrum hydroxycinnamic degradation pathway is an original coenzyme A-dependent β-oxidative deacetylation that could also transform p-coumaric and caffeic acids. Finally, we showed that this pathway enables the metabolism of toxic compounds from plants and their use for growth, likely providing the species an ecological advantage in hydroxycinnamic-rich environments, such as plant roots or decaying plant materials.

  18. Long-term stability study of L-adrenaline injections: Kinetics of sulfonation and racemization pathways of drug degradation.

    Science.gov (United States)

    Stepensky, David; Chorny, Michael; Dabour, Ziad; Schumacher, Ilana

    2004-04-01

    Injectable formulations of L-adrenaline are commonly used in emergency medicine. Despite numerous studies, the comparative contribution and kinetics of the L-adrenaline inactivation pathways during storage have not been conclusively evaluated. We examined the kinetics of L-adrenaline degradation in a prospective study and determined the extent of drug inactivation by different pathways during and beyond the stipulated product shelf-life in 42 batches of adrenaline ampules stored under controlled conditions. The content of L-adrenaline and degradation products was determined with a chiral high-performance liquid chromatography (HPLC) assay, and the degradation products were identified by mass spectrometric detection as D-adrenaline and L- and D-adrenaline sulfonate. The kinetics of the content change with storage was analyzed simultaneously for L-adrenaline and the degradation products using kinetic modeling. The lower acceptable level of adrenaline content in the formulation stated by US Pharmacopoeia (90% as a sum of L- and D-isomers) was attained after 2.0 years of storage, at which time the content of the therapeutically active L-isomer amounted to as low as 85%. The modeling revealed significant differences in the degradation kinetics in the formulations produced before and after 1997, whose cause remained unidentified in this study. Copyright 2004 Wiley-Liss, Inc. and the American Pharmacists Association.

  19. Androgens upregulate Cdc25C protein by inhibiting its proteasomal and lysosomal degradation pathways.

    Directory of Open Access Journals (Sweden)

    Yu-Wei Chou

    Full Text Available Cdc25C is a cell cycle protein of the dual specificity phosphatase family essential for activating the cdk1/Cyclin B1 complex in cells entering into mitosis. Since altered cell cycle is a hallmark of human cancers, we investigated androgen regulation of Cdc25C protein in human prostate cancer (PCa cells, including androgen-sensitive (AS LNCaP C-33 cells and androgen-independent (AI LNCaP C-81 as well as PC-3 cells. In the regular culture condition containing fetal bovine serum (FBS, Cdc25C protein levels were similar in these PCa cells. In a steroid-reduced condition, Cdc25C protein was greatly decreased in AS C-33 cells but not AI C-81 or PC-3 cells. In androgen-treated C-33 cells, the Cdc25C protein level was greatly elevated, following a dose- and a time-dependent manner, correlating with increased cell proliferation. This androgen effect was blocked by Casodex, an androgen receptor blocker. Nevertheless, epidermal growth factor (EGF, a growth stimulator of PCa cells, could only increase Cdc25C protein level by about 1.5-fold. Altered expression of Cdc25C in C-33 cells and PC-3 cells by cDNA and/or shRNA transfection is associated with the corresponding changes of cell growth and Cyclin B1 protein level. Actinomycin D and cycloheximide could only partially block androgen-induced Cdc25C protein level. Treatments with both proteasomal and lysosomal inhibitors resulted in elevated Cdc25C protein levels. Immunoprecipitation revealed that androgens reduced the ubiquitination of Cdc25C proteins. These results show for the first time that Cdc25C protein plays a role in regulating PCa cell growth, and androgen treatments, but not EGF, greatly increase Cdc25C protein levels in AS PCa cells, which is in part by decreasing its degradation. These results can lead to advanced PCa therapy via up-regulating the degradation pathways of Cdc25C protein.

  20. Reaction pathway of the degradation of the p-hydroxybenzoic acid by sulfate radical generated by ionizing radiations

    International Nuclear Information System (INIS)

    Criquet, Justine; Leitner, Nathalie Karpel Vel

    2015-01-01

    The degradation of p-hydroxybenzoic acid (HBA) in aqueous solutions by ionizing radiation was studied. The phenolic pollutant was easily removed by the electron beam irradiation, as more than 80% of the initial 100 µM introduced was degraded for a dose of 600 Gy. It was shown that the addition of persulfate, producing the sulfate radical as additional reactive species, induced a change in the reaction pathway. LC–MS analyses were performed in order to identify the different by-products formed. In the absence of persulfate, the main by-product formed was 3,4-dihydroxybenzoic acid, while in presence of persulfate, 1,4-benzoquinone was detected and the hydroxylated by-products were not present. A reaction pathway of HBA degradation by hydroxyl and sulfate radicals was proposed from the identification of the chemical structure of the different by-products detected. The influences of pH and dissolved oxygen were also studied. A high decline of HBA degradation was observed at pH 11 compared to pH 4.5, this decrease was minimized in the presence of persulfate. The dissolved oxygen concentration was found to be a limiting parameter of HBA degradation, however an excess of dissolved oxygen in solution did not improve the degradation to a large extent. - Highlights: • p-Hydroxybenzoic acid (HBA) is easily removed by e-beam irradiation. • The sulfate radicals formed from persulfate induce loss of the benzoic acid skeleton. • The dissolved oxygen concentration is a limiting parameter of the HBA degradation. • The effect of pH is minimized in presence of persulfate

  1. Photochemical of Polychlorinated biphenyl by the photolysis and ...

    African Journals Online (AJOL)

    pressure mercury lamp. The whole Lamp was immersed in a reactor thermostat controlling the temperature at 32 ± 2 °C. The Polychlorinated biphenyls (PCBs) were analyzed by GC/ECD. The degradation of PCBs in terms of one, two and three lamp ...

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

    International Nuclear Information System (INIS)

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

    2004-01-01

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

  3. Assessing degradation and recovery pathways in lakes impacted by eutrophication using the sediment record

    Directory of Open Access Journals (Sweden)

    Helen eBennion

    2015-08-01

    Full Text Available Efforts to restore enriched lakes have increased yet there remains uncertainty about whether restoration targets can be achieved and over what timescale. Paleoecological techniques, principally diatom analyses, were used to examine the degree of impact and recovery in 12 European lakes subject to eutrophication and subsequent reduction in nutrient loading. Dissimilarity scores showed that all sites experienced progressive deviation from the reference sample (core bottom prior to nutrient reduction, and principal curves indicated gradual compositional change with enrichment. When additive models were applied to the latter, the changes were statistically significant in 9 of the 12 sites. Shifts in diatom composition following reduction in nutrient loading were more equivocal, with a reversal towards the reference flora seen only in four of the deep lakes and one of the shallow lakes. Of these, only two were significant (Lake Bled and Mjøsa. Alternative nutrient sources seem to explain the lack of apparent recovery in the other deep lakes. In three shallow lakes diatom assemblages were replaced by a community associated with lower productivity but not the one seen prior to enrichment. Internal loading and top down control may influence recovery in shallow lakes and climate change may have confounded recovery in several of the study sites. Hence, ecosystem recovery is not simply a reversal of the degradation pathway and may take several decades to complete or, for some lakes, may not take place at all. By assessing ecological change over a decadal to centennial timescale, the study highlights the important role that paleolimnology can play in establishing a benchmark against which managers can evaluate the degree to which their restoration efforts are successful.

  4. Porcine arterivirus activates the NF-κB pathway through IκB degradation

    International Nuclear Information System (INIS)

    Lee, Sang-Myeong; Kleiboeker, Steven B.

    2005-01-01

    Nuclear factor-kappaB (NF-κB) is a critical regulator of innate and adaptive immune function as well as cell proliferation and survival. The present study demonstrated for the first time that a virus belonging to the Arteriviridae family activates NF-κB in MARC-145 cells and alveolar macrophages. In porcine reproductive and respiratory syndrome virus (PRRSV)-infected cells, NF-κB activation was characterized by translocation of NF-κB from the cytoplasm to the nucleus, increased DNA binding activity, and NF-κB-regulated gene expression. NF-κB activation was increased as PRRSV infection progressed and in a viral dose-dependent manner. UV-inactivation of PRRSV significantly reduced the level of NF-κB activation. Degradation of IκB protein was detected late in PRRSV infection, and overexpression of the dominant negative form of IκBα (IκBαDN) significantly suppressed NF-κB activation induced by PRRSV. However, IκBαDN did not affect viral replication and viral cytopathic effect. PRRSV infection induced oxidative stress in cells by generating reactive oxygen species (ROS), and antioxidants inhibited NF-κB DNA binding activity in PRRSV-infected cells, suggesting ROS as a mechanism by which NF-κB was activated by PRRSV infection. Moreover, NF-κB-dependent expression of matrix metalloproteinase (MMP)-2 and MMP-9 was observed in PRRSV-infected cells, an observation which implies that NF-κB activation is a biologically significant aspect of PRRSV pathogenesis. The results presented here provide a basis for understanding molecular pathways of pathology and immune evasion associated with disease caused by PRRSV

  5. A vacuolar carboxypeptidase mutant of Arabidopsis thaliana is degraded by the ERAD pathway independently of its N-glycan

    International Nuclear Information System (INIS)

    Yamamoto, Masaya; Kawanabe, Mitsuyoshi; Hayashi, Yoko; Endo, Toshiya; Nishikawa, Shuh-ichi

    2010-01-01

    Misfolded proteins produced in the endoplasmic reticulum (ER) are degraded by a mechanism, the ER-associated degradation (ERAD). Here we report establishment of the experimental system to analyze the ERAD in plant cells. Carboxypeptidase Y (CPY) is a vacuolar enzyme and its mutant CPY* is degraded by the ERAD in yeast. Since Arabidopsis thaliana has AtCPY, an ortholog of yeast CPY, we constructed and expressed fusion proteins consisting of AtCPY and GFP and of AtCPY*, which carries a mutation homologous to yeast CPY*, and GFP in A. thaliana cells. While AtCPY-GFP was efficiently transported to the vacuole, AtCPY*-GFP was retained in the ER to be degraded in proteasome- and Cdc48-dependent manners. We also found that AtCPY*-GFP was degraded by the ERAD in yeast cells, but that its single N-glycan did not function as a degradation signal in yeast or plant cells. Therefore, AtCPY*-GFP can be used as a marker protein to analyze the ERAD pathway, likely for nonglycosylated substrates, in plant cells.

  6. Diclofenac degradation in water by FeCeOx catalyzed H2O2: Influencing factors, mechanism and pathways.

    Science.gov (United States)

    Chong, Shan; Zhang, Guangming; Zhang, Nan; Liu, Yucan; Huang, Ting; Chang, Huazhen

    2017-07-15

    The degradation of diclofenac in a like Fenton system, FeCeO x -H 2 O 2 , was studied in details. The influencing factors, reaction kinetics, reaction mechanism and degradation pathways of diclofenac were investigated. The optimum conditions were at a solution pH of 5.0, H 2 O 2 concentration of 3.0mmol/L, diclofenac initial concentration of 0.07mmol/L, FeCeO x dosage of 0.5g/L, and 84% degradation of diclofenac was achieved within 40min. The kinetics of FeCeO x catalyzed H 2 O 2 process involved adsorption-dominating and degradation-dominating stages and fitted pseudo-second order model and pseudo-first order model, respectively. Singlet oxygen 1 O 2 was the primary intermediate oxidative species in the degradation process; superoxide radical anion O 2 - also participated in the reaction. The surface cerium and iron sites and the oxygen vacancies in the FeCeO x catalyst were proposed to play an important role in H 2 O 2 decomposition and active species generation. The detected intermediates were identified as hydroxylated derivatives (m/z of 310, 326 and 298), quinone imine compounds (m/z of 308, 278 and 264) and hydroxyl phenylamine (m/z of 178). The majority intermediates were hydroxylated derivatives and the minority was hydroxyl phenylamine. The degradation pathways were proposed to involve hydroxylation, decarboxylation, dehydrogenation and CN bond cleavage. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Biodegradation of chlorimuron-ethyl and the associated degradation pathway by Rhodococcus sp. D310-1.

    Science.gov (United States)

    Li, Chunyan; Zang, Hailian; Yu, Qi; Lv, Tongyang; Cheng, Yi; Cheng, Xiaosong; Liu, Keran; Liu, Wanjun; Xu, Pianpian; Lan, Chuanzeng

    2016-05-01

    Chlorimuron-ethyl is a typical long-term residual sulfonylurea herbicide, and strategies for its removal have attracted increasing attention. Microbial degradation is considered the most acceptable dissipation method. In this study, we optimized the cultivation conditions (substrate concentration, pH, inoculum concentration, and temperature) of the chlorimuron-ethyl-degrading bacterium Rhodococcus sp. D310-1 using response surface methodology (RSM) to improve the biodegradation efficiency. A maximum biodegradation rate of 88.95 % was obtained. The Andrews model was used to describe the changes in the specific degradation rate as the substrate concentration increased. Chlorimuron-ethyl could be transformed with a maximum specific degradation rate (q max), half-saturation constant (K S), and inhibition constant (K i) of 0.4327 day(-1), 63.50045 mg L(-1), and 156.76666 mg L(-1), respectively. Eight biodegradation products (2-amino-4-chloro-6-methoxypyrimidine, ethyl 2-sulfamoyl benzoate, 2-sulfamoyl benzoic acid, o-benzoic sulfimide, 2-[[(4-chloro-6-methoxy-2-pyrimidinyl) carbamoyl] sulfamoyl] benzoic acid, ethyl 2-carbonyl sulfamoyl benzoate, ethyl 2-benzenesulfonyl isocyanate benzoate, and N,N-2(ethyl formate)benzene sulfonylurea) were identified, and three possible degradation pathways were proposed based on the results of high performance liquid chromatography HPLC, liquid chromatography tandem mass spectroscopy (LC-MS/MS), and Fourier transform infrared spectroscopy (FTIR) analyses and the relevant literature. This systematic study is the first to examine the chlorimuron-ethyl degradation pathways of the genus Rhodococcus.

  8. Dietary pectic glycans are degraded by coordinated enzyme pathways in human colonic Bacteroides

    DEFF Research Database (Denmark)

    Luis, Ana S.; Briggs, Jonathon; Zhang, Xiaoyang

    2018-01-01

    the remnants of other pectin domains attached to rhamnogalacturonan-I, and nine enzymes that contribute to the degradation of the backbone that makes up a rhamnose-GalA repeating unit. The catalytic properties of the pectin-degrading enzymes are optimized to protect the glycan cues that activate the specific...

  9. Adsorption and Photocatalytic Decomposition of the β-Blocker Metoprolol in Aqueous Titanium Dioxide Suspensions: Kinetics, Intermediates, and Degradation Pathways

    Directory of Open Access Journals (Sweden)

    Violette Romero

    2013-01-01

    Full Text Available This study reports the photocatalytic degradation of the β-blocker metoprolol (MET using TiO2 suspended as catalyst. A series of photoexperiments were carried out by a UV lamp, emitting in the 250–400 nm range, providing information about the absorption of radiation in the photoreactor wall. The influence of the radiation wavelength on the MET photooxidation rate was investigated using a filter cutting out wavelengths shorter than 280 nm. Effects of photolysis and adsorption at different initial pH were studied to evaluate noncatalytic degradation for this pharmaceutical. MET adsorption onto titania was fitted to two-parameter Langmuir isotherm. From adsorption results it appears that the photocatalytic degradation can occur mainly on the surface of TiO2. MET removed by photocatalysis was 100% conditions within 300 min, while only 26% was achieved by photolysis at the same time. TiO2 photocatalysis degradation of MET in the first stage of the reaction followed approximately a pseudo-first-order model. The major reaction intermediates were identified by LC/MS analysis such as 3-(propan-2-ylaminopropane-1,2-diol or 3-aminoprop-1-en-2-ol. Based on the identified intermediates, a photocatalytic degradation pathway was proposed, including the cleavage of side chain and the hydroxylation addition to the parent compounds.

  10. Plant exudates promote PCB degradation by a rhodococcal rhizobacteria

    Energy Technology Data Exchange (ETDEWEB)

    Toussaint, Jean-Patrick; Pham, Thi Thanh My; Barriault, Diane; Sylvestre, Michel [Instiut National de la Recherche Scientifique INRS, Laval, QC (Canada). Inst. Armand-Frappier

    2012-09-15

    Rhodococcus erythropolis U23A is a polychlorinated biphenyl (PCB)-degrading bacterium isolated from the rhizosphere of plants grown on a PCB-contaminated soil. Strain U23A bphA exhibited 99% identity with bphA1 of Rhodococcus globerulus P6. We grew Arabidopsis thaliana in a hydroponic axenic system, collected, and concentrated the plant secondary metabolite-containing root exudates. Strain U23A exhibited a chemotactic response toward these root exudates. In a root colonizing assay, the number of cells of strain U23A associated to the plant roots (5.7 x 105 CFU g{sup -1}) was greater than the number remaining in the surrounding sand (4.5 x 104 CFU g{sup -1}). Furthermore, the exudates could support the growth of strain U23A. In a resting cell suspension assay, cells grown in a minimal medium containing Arabidopsis root exudates as sole growth substrate were able to metabolize 2,3,4'- and 2,3',4-trichlorobiphenyl. However, no significant degradation of any of congeners was observed for control cells grown on Luria-Bertani medium. Although strain U23A was unable to grow on any of the flavonoids identified in root exudates, biphenyl-induced cells metabolized flavanone, one of the major root exudate components. In addition, when used as co-substrate with sodium acetate, flavanone was as efficient as biphenyl to induce the biphenyl catabolic pathway of strain U23A. Together, these data provide supporting evidence that some rhodococci can live in soil in close association with plant roots and that root exudates can support their growth and trigger their PCB-degrading ability. This suggests that, like the flagellated Gram-negative bacteria, non-flagellated rhodococci may also play a key role in the degradation of persistent pollutants. (orig.)

  11. The regulatory role of reversible phosphorylation in the chlorophyll degradation pathway

    Science.gov (United States)

    Senescence represents the final stage of plant development and is characterized by several processes including the systematic degradation of the photosynthetic apparatus and chlorophyll molecules inside chloroplasts. Normally, chlorophyll is catabolized to colorless compounds through a series of enz...

  12. Novel Pathway of Salicylate Degradation by Streptomyces sp. Strain WA46

    OpenAIRE

    Ishiyama, Daisuke; Vujaklija, Dusica; Davies, Julian

    2004-01-01

    A novel salicylate-degrading Streptomyces sp., strain WA46, was identified by UV fluorescence on solid minimal medium containing salicylate; trace amounts of gentisate were detected by high-pressure liquid chromatography when strain WA46 was grown with salicylate. PCR amplification of WA46 DNA with degenerate primers for gentisate 1,2-dioxygenase (GDO) genes produced an amplicon of the expected size. Sequential PCR with nested GDO primers was then used to identify a salicylate degradation gen...

  13. Degradation pathways of 1-methylphenanthrene in bacterial Sphingobium sp. MP9-4 isolated from petroleum-contaminated soil.

    Science.gov (United States)

    Zhong, Jianan; Luo, Lijuan; Chen, Baowei; Sha, Sha; Qing, Qing; Tam, Nora F Y; Zhang, Yong; Luan, Tiangang

    2017-01-30

    Alkylated polycyclic aromatic hydrocarbons (PAHs) are abundant in petroleum, and alkylated phenanthrenes are considered as the primary PAHs during some oil spill events. Bacterial strain of Sphingobium sp. MP9-4, isolated from petroleum-contaminated soil, was efficient to degrade 1-methylphenanthrene (1-MP). A detailed metabolism map of 1-MP in this strain was delineated based on analysis of metabolites with gas chromatograph-mass spectrometer (GC-MS). 1-MP was initially oxidized via two different biochemical strategies, including benzene ring and methyl-group attacks. Benzene ring attack was initiated with dioxygenation of the non-methylated aromatic ring via similar degradation pathways of phenanthrene (PHE) by bacteria. For methyl-group attack, mono oxygenase system was involved and more diverse enzymes were needed than that of PHE degradation. This study enhances the understanding of the metabolic pathways of alkylated PAHs and shows the significant potential of Sphingobium sp. MP9-4 for the bioremediation of alkylated PAHs contaminated environments. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Mechanism and Reaction Pathways for Microcystin-LR Degradation through UV/H2O2 Treatment.

    Directory of Open Access Journals (Sweden)

    Yafeng Liu

    Full Text Available Microcystin-LR (MCLR is the most common cyanotoxin in contaminated aquatic systems. MCLR inhibits protein phosphatases 1 and 2A, leading to liver damage and tumor formation. MCLR is relatively stable owing to its cyclic structures. The combined UV/H2O2 technology can degrade MCLR efficiently. The second-order rate constant of the reaction between MCLR and hydroxyl radical (·OH is 2.79(±0.23×1010 M-1 s-1 based on the competition kinetics model using nitrobenzene as reference compound. The probable degradation pathway was analyzed through liquid chromatography mass spectrometry. Results suggested that the major destruction pathways of MCLR were initiated by ·OH attack on the benzene ring and diene of the Adda side chain. The corresponding aldehyde or ketone peptide residues were formed through further oxidation. Another minor destruction pathway involved ·OH attack on the methoxy group of the Adda side chain, followed by complete removal of the methoxy group. The combined UV/H2O2 system is a promising technology for MCLR removal in contaminated aquatic systems.

  15. Photolytic and photocatalytic degradation of quinclorac in ultrapure and paddy field water: identification of transformation products and pathways.

    Science.gov (United States)

    Pareja, Lucía; Pérez-Parada, Andrés; Agüera, Ana; Cesio, Verónica; Heinzen, Horacio; Fernández-Alba, Amadeo R

    2012-05-01

    Quinclorac (QNC) is an effective but rather persistent herbicide commonly used in rice production. This herbicide presents a mean persistence in the environment so its residues are considered of environmental relevance. However, few studies have been conducted to investigate its environmental behavior and degradation. In the present work, direct photolysis and TiO(2) photocatalysis of the target compound in ultrapure and paddy field water were investigated. After 10h photolysis in ultrapure water, the concentration of QNC declined 26% and 54% at 250 and 700 W m(-2), respectively. However, the amount of quinclorac in paddy field water remained almost constant under the same irradiation conditions. QNC dissipated completely after 40 min of TiO(2) photocatalysis in ultrapure water, whereas 130 min were necessary to degrade 98% of the initial concentration in paddy field water. Possible QNC photolytic and photocatalytic degradation pathways are proposed after structure elucidation of the main transformation products, through liquid chromatography-electrospray ionization-quadrupole time-of-flight mass spectrometry and exact mass measurements. Pyridine ring hydroxylation at C-9 followed by ring opening and/or oxidative dechlorination were the key steps of QNC degradation. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Evidence of distinct pathways for bacterial degradation of the steroid compound cholate suggests the potential for metabolic interactions by interspecies cross-feeding.

    Science.gov (United States)

    Holert, Johannes; Yücel, Onur; Suvekbala, Vemparthan; Kulić, Zarko; Möller, Heiko; Philipp, Bodo

    2014-05-01

    The distribution and the metabolic pathways of bacteria degrading steroid compounds released by eukaryotic organisms were investigated using the bile salt cholate as model substrate. Cholate-degrading bacteria could be readily isolated from freshwater environments. All isolated strains transiently released steroid degradation intermediates into culture supernatants before their further degradation. Cholate degradation could be initiated via two different reaction sequences. Most strains degraded cholate via a reaction sequence known from the model organism Pseudomonas sp. strain Chol1 releasing intermediates with a 3-keto-Δ(1,4) -diene structure of the steroid skeleton. The actinobacterium Dietzia sp. strain Chol2 degraded cholate via a different and yet unexplored reaction sequence releasing intermediates with a 3-keto-Δ(4,6) -diene-7-deoxy structure of the steroid skeleton such as 3,12-dioxo-4,6-choldienoic acid (DOCDA). Using DOCDA as substrate, two Alphaproteobacteria, strains Chol10-11, were isolated that produced the same cholate degradation intermediates as strain Chol2. With DOCDA as substrate for Pseudomonas sp. strain Chol1 only the side chain was degraded while the ring system was transformed into novel steroid compounds accumulating as dead-end metabolites. These metabolites could be degraded by the DOCDA-producing strains Chol10-11. These results indicate that bacteria with potentially different pathways for cholate degradation coexist in natural habitats and may interact via interspecies cross-feeding. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  17. Nicotine Dehydrogenase Complexed with 6-Hydroxypseudooxynicotine Oxidase Involved in the Hybrid Nicotine-Degrading Pathway in Agrobacterium tumefaciens S33.

    Science.gov (United States)

    Li, Huili; Xie, Kebo; Yu, Wenjun; Hu, Liejie; Huang, Haiyan; Xie, Huijun; Wang, Shuning

    2016-01-04

    Nicotine, a major toxic alkaloid in tobacco wastes, is degraded by bacteria, mainly via pyridine and pyrrolidine pathways. Previously, we discovered a new hybrid of the pyridine and pyrrolidine pathways in Agrobacterium tumefaciens S33 and characterized its key enzyme 6-hydroxy-3-succinoylpyridine (HSP) hydroxylase. Here, we purified the nicotine dehydrogenase initializing the nicotine degradation from the strain and found that it forms a complex with a novel 6-hydroxypseudooxynicotine oxidase. The purified complex is composed of three different subunits encoded by ndhAB and pno, where ndhA and ndhB overlap by 4 bp and are ∼26 kb away from pno. As predicted from the gene sequences and from chemical analyses, NdhA (82.4 kDa) and NdhB (17.1 kDa) harbor a molybdopterin cofactor and two [2Fe-2S] clusters, respectively, whereas Pno (73.3 kDa) harbors an flavin mononucleotide and a [4Fe-4S] cluster. Mutants with disrupted ndhA or ndhB genes did not grow on nicotine but grew well on 6-hydroxynicotine and HSP, whereas the pno mutant did not grow on nicotine or 6-hydroxynicotine but grew well on HSP, indicating that NdhA and NdhB are responsible for initialization of nicotine oxidation. We successfully expressed pno in Escherichia coli and found that the recombinant Pno presented 2,6-dichlorophenolindophenol reduction activity when it was coupled with 6-hydroxynicotine oxidation. The determination of reaction products catalyzed by the purified enzymes or mutants indicated that NdhAB catalyzed nicotine oxidation to 6-hydroxynicotine, whereas Pno oxidized 6-hydroxypseudooxynicotine to 6-hydroxy-3-succinoylsemialdehyde pyridine. These results provide new insights into this novel hybrid pathway of nicotine degradation in A. tumefaciens S33. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  18. Microwave-Enhanced Photolysis of Norfloxacin: Kinetics, Matrix Effects, and Degradation Pathways

    OpenAIRE

    Liao, Wenchao; Sharma, Virender K.; Xu, Su; Li, Qingsong; Wang, Lei

    2017-01-01

    Degradation of norfloxacin (NOR) was studied using a combination of microwave and UV irradiation methods (MW/UV process). Remarkable synergistic effect was found between MW and UV light. The removal rate with the MW/UV process was much faster than that with UV light irradiation only. Degradation of NOR followed second-order kinetics and ~72% of NOR could be removed in the first 5 min of MW/UV reaction. Influence of inorganic ions (cations (K+, Mg2+, Ca2+, Cu2+) and anions (Cl−, SO4 2−, NO3 −,...

  19. The deep-subsurface sulfate reducer Desulfotomaculum kuznetsovii employs two methanol-degrading pathways

    NARCIS (Netherlands)

    Sousa, Diana Z.; Visser, Michael; Gelder, Van Antonie H.; Boeren, Sjef; Pieterse, Mervin M.; Pinkse, Martijn W.H.; Verhaert, Peter D.E.M.; Vogt, Carsten; Franke, Steffi; Kümmel, Steffen; Stams, Alfons J.M.

    2018-01-01

    Methanol is generally metabolized through a pathway initiated by a cobalamine-containing methanol methyltransferase by anaerobic methylotrophs (such as methanogens and acetogens), or through oxidation to formaldehyde using a methanol dehydrogenase by aerobes. Methanol is an important substrate in

  20. Identification and characterization of the furfural and 5-(hydroxymethyl)furfural degradation pathways of Cupriavidus basilensis HMF14

    Energy Technology Data Exchange (ETDEWEB)

    Koopman, F.; De Winde, J.H. [Bio-Based Sustainable Industrial Chemistry (B-Basic), Delft University of Technology, Department of Biotechnology, Julianalaan 67, 2628 BC, Delft (Netherlands); Wierckx, N. [Kluyver Centre for Genomics of Industrial Fermentation, P.O. Box 5057, 2600 GB, Delft (Netherlands); Ruijssenaars, H.J. [Netherlands Organization for Applied Scientific Research, Quality of Life, Department of Bioconversion, Julianalaan 67, 2628 BC, Delft (Netherlands); O' Neal Ingram, L. (ed.) [University of Florida, Gainesville, Gainesville, FL (United States)

    2010-03-16

    The toxic fermentation inhibitors in lignocellulosic hydrolysates pose significant problems for the production of second-generation biofuels and biochemicals. Among these inhibitors, 5-(hydroxymethyl) furfural (HMF) and furfural are specifically notorious. In this study, we describe the complete molecular identification and characterization of the pathway by which Cupriavidus basilensis HMF14 metabolizes HMF and furfural. The identification of this pathway enabled the construction of an HMF and furfural-metabolizing Pseudomonas putida. The genetic information obtained furthermore enabled us to predict the HMF and furfural degrading capabilities of sequenced bacterial species that had not previously been connected to furanic aldehyde metabolism. These results pave the way for in situ detoxification of lignocellulosic hydrolysates, which is a major step toward improved efficiency of utilization of lignocellulosic feedstock.

  1. Characterization of a new degradation product of nifedipine formed on catalysis by atenolol: A typical case of alteration of degradation pathway of one drug by another.

    Science.gov (United States)

    Handa, Tarun; Singh, Saranjit; Singh, Inder Pal

    2014-02-01

    An increasing interest is being shown throughout the world on the use of fixed-dose combinations of drugs in the therapy of select diseases, like cardiovascular diseases, due to their multiple advantages. Though the main criterion for combining drugs in a single dosage form is the rationale, but consideration like stability of formulation is equally important, due to an added aspect of drug-drug interaction. The objective of this study was to evaluate interaction among the drugs in an antihypertensive combination of nifedipine and atenolol. Nifedipine is a known light sensitive drug, which degrades via intra-molecular mechanisms to nitro- and nitroso-pyridine analogs, along with a few minor secondary products that are formed through inter-molecular interactions amongst primary degradation products and their intermediates. Atenolol is reasonably stable weakly basic drug that is mainly hydrolyzed at acetamide terminal amide moiety to its corresponding carboxylic acid. To the best of our knowledge, there is no known information on chemical compatibility among the two drugs. The present study involved subjecting of nifedipine, atenolol and their combination to a variety of accelerated and stress conditions. HPLC studies revealed formation of a new product in the mixture of two drugs (∼2%), which was also generated from nifedipine alone, but at trace levels (product was isolated by preparative chromatography and subjected to indepth studies for its characterization. Ultra-violet, FT-IR, mass spectrometric and nuclear magnetic resonance spectroscopic studies highlighted that the principal photo-degradation pathway of nifedipine was modified and diverted in the presence of atenolol. To verify the same, a study was conducted employing two other β-blockers with similar structures to atenolol, and the same product was formed in relatively higher quantity therein also. The new product is postulated to be produced as a result of rearrangement of hydroxylamine intermediate

  2. Enhanced photocatalytic performance and degradation pathway of Rhodamine B over hierarchical double-shelled zinc nickel oxide hollow sphere heterojunction

    Science.gov (United States)

    Zhang, Ying; Zhou, Jiabin; Cai, Weiquan; Zhou, Jun; Li, Zhen

    2018-02-01

    In this study, hierarchical double-shelled NiO/ZnO hollow spheres heterojunction were prepared by calcination of the metallic organic frameworks (MOFs) as a sacrificial template in air via a one-step solvothermal method. Additionally, the photocatalytic activity of the as-prepared samples for the degradation of Rhodamine B (RhB) under UV-vis light irradiation were also investigated. NiO/ZnO microsphere comprised a core and a shell with unique hierarchically porous structure. The photocatalytic results showed that NiO/ZnO hollow spheres exhibited excellent catalytic activity for RhB degradation, causing complete decomposition of RhB (200 mL of 10 g/L) under UV-vis light irradiation within 3 h. Furthermore, the degradation pathway was proposed on the basis of the intermediates during the photodegradation process using liquid chromatography analysis coupled with mass spectroscopy (LC-MS). The improvement in photocatalytic performance could be attributed to the p-n heterojunction in the NiO/ZnO hollow spheres with hierarchically porous structure and the strong double-shell binding interaction, which enhances adsorption of the dye molecules on the catalyst surface and facilitates the electron/hole transfer within the framework. The degradation mechanism of pollutant is ascribed to the hydroxyl radicals (rad OH), which is the main oxidative species for the photocatalytic degradation of RhB. This work provides a facile and effective approach for the fabrication of porous metal oxides heterojunction with high photocatalytic activity and thus can be potentially used in the environmental purification.

  3. Peroxisome degradation in Saccharomyces cerevisiae is dependent on machinery of macroautophagy and the Cvt pathway

    NARCIS (Netherlands)

    Hutchins, Maria U.; Veenhuis, Marten; Klionsky, Daniel J.

    1999-01-01

    Organelle biogenesis and turnover are necessary to maintain biochemical processes that are appropriate to the needs of the eukaryotic cell. Specific degradation of organelles in response to changing environmental cues is one aspect of achieving proper metabolic function. For example, the yeast

  4. Microbial degradation pathways of the herbicide dichlobenil in soils with different history of dichlobenil-exposure

    International Nuclear Information System (INIS)

    Holtze, Maria S.; Hansen, Hans Christian B.; Juhler, Rene K.; Sorensen, Jan; Aamand, Jens

    2007-01-01

    This is the first detailed study of metabolite production during degradation of the herbicide 2,6-dichlorobenzonitrile (dichlobenil). Degradation of dichlobenil and three potential metabolites: 2,6-dichlorobenzamide (BAM), 2,6-dichlorobenzoic acid (2,6-DCBA) and ortho-chlorobenzamide (OBAM) was studied in soils either previously exposed or not exposed to dichlobenil using a newly developed HPLC method. Dichlobenil was degraded in all four soils; BAM and 2,6-DCBA were only degraded in soils previously exposed to dichlobenil (100% within 35-56 days and 85-100% in 56 days, respectively), and OBAM in all four soils (25-33% removal in 48 days). BAM produced from dichlobenil was either hydrolyzed to 2,6-DCBA or dechlorinated to OBAM, which was further hydrolyzed to ortho-chlorobenzoic acid. BAM was rapidly mineralized in previously exposed soils only. All potential metabolites and the finding that BAM was a dead-end metabolite of dichlobenil in soils not previously exposed to dichlobenil needs to be included in risk assessments of the use of dichlobenil. - BAM produced from dichlobenil was either hydrolyzed to 2,6-DCBA or dechlorinated to OBAM, which was further hydrolyzed to ortho-chlorobenzoic acid

  5. Switching Oxygen Reduction Pathway by Exfoliating Graphitic Carbon Nitride for Enhanced Photocatalytic Phenol Degradation.

    Science.gov (United States)

    Zhang, Hui; Guo, Liang-Hong; Zhao, Lixia; Wan, Bin; Yang, Yu

    2015-03-19

    The selectivity of molecular oxygen activation on the exfoliated graphitic carbon nitride (g-C3N4) and its influence on the photocatalytic phenol degradation process were demonstrated. Compared with bulk g-C3N4, the exfoliated nanosheet yielded a 3-fold enhancement in photocatalytic phenol degradation. ROS trapping experiments demonstrated that although the direct hole oxidation was mainly responsible for phenol photodegradation on both g-C3N4 catalysts, molecular oxygen activation processes on their surface greatly influenced the whole phenol degradation efficiency. Reactive oxygen species and Raman spectroscopy measurements revealed that oxygen was preferentially reduced to ·O2(-) by one-electron transfer on bulk g-C3N4, while on g-C3N4 nanosheet the production of H2O2 via a two-electron transfer process was favored due to the rapid formation of surface-stabilized 1,4-endoperoxide. The latter process not only promotes the separation of photogenerated electron-hole pairs but also greatly facilitates reactive oxygen species formation and subsequently enhances phenol degradation.

  6. 13C Tracers for Glucose Degrading Pathway Discrimination in Gluconobacter oxydans 621H

    Directory of Open Access Journals (Sweden)

    Steffen Ostermann

    2015-09-01

    Full Text Available Gluconobacter oxydans 621H is used as an industrial production organism due to its exceptional ability to incompletely oxidize a great variety of carbohydrates in the periplasm. With glucose as the carbon source, up to 90% of the initial concentration is oxidized periplasmatically to gluconate and ketogluconates. Growth on glucose is biphasic and intracellular sugar catabolism proceeds via the Entner–Doudoroff pathway (EDP and the pentose phosphate pathway (PPP. Here we studied the in vivo contributions of the two pathways to glucose catabolism on a microtiter scale. In our approach we applied specifically 13C labeled glucose, whereby a labeling pattern in alanine was generated intracellularly. This method revealed a dynamic growth phase-dependent pathway activity with increased activity of EDP in the first and PPP in the second growth phase, respectively. Evidence for a growth phase-independent decarboxylation-carboxylation cycle around the pyruvate node was obtained from 13C fragmentation patterns of alanine. For the first time, down-scaled microtiter plate cultivation together with 13C-labeled substrate was applied for G. oxydans to elucidate pathway operation, exhibiting reasonable labeling costs and allowing for sufficient replicate experiments.

  7. Electrochemical degradation of sulfonamides at BDD electrode: Kinetics, reaction pathway and eco-toxicity evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Fabiańska, Aleksandra; Białk-Bielińska, Anna; Stepnowski, Piotr [Faculty of Chemistry, University of Gdansk, ul. Wita Stwosza 63, 80-952 Gdansk (Poland); Stolte, Stefan [Faculty of Chemistry, University of Gdansk, ul. Wita Stwosza 63, 80-952 Gdansk (Poland); UFT-Centre of Environmental Research and Sustainable Technology, University of Bremen, Leobener Straße UFT, D-28359 Bremen (Germany); Siedlecka, Ewa Maria, E-mail: ewa.siedlecka@ug.edu.pl [Faculty of Chemistry, University of Gdansk, ul. Wita Stwosza 63, 80-952 Gdansk (Poland)

    2014-09-15

    Highlights: • SNs were electrochemically oxidized at BDD in one compartment reactor. • The efficiency of SN degradation was the highest in effluents from municipal WWTP. • The electro-degradation SNs based on oxidation but reduction was also possible. • Electrochemical oxidation of SNs led in some cases to mixtures toxic to L. minor. - Abstract: The investigation dealt with electrochemical oxidation of five sulfonamides (SNs): sulfadiazine (SDZ), sulfathiazole (STZ), sulfamerazine (SMR), sulfamethazine (SMN) and sulfadimethoxine (SDM) in aqueous solution at boron-doped diamond (BDD) electrode. All studied sulfonamides were degraded according to a pseudo first order kinetics. The structure of SNs had no significant effect on the values of pseudo first order rate constants. Increased degradation efficiency was observed in higher temperature and in acidic pH. Due to the presence of chlorine and nitrate SNs were more effectively oxidized from municipal wastewater treatment plant (WWTP) effluents than from pure supporting electrolyte Na{sub 2}SO{sub 4}. The intermediates identified by LC–MS and GC–MS analysis suggested that the hydroxyl radicals attack mainly the S-N bond, but also the aromatic ring systems (aniline, pyrimidine or triazole) of SNs. Finally, the toxicity of the SNs solutions and effluents after electrochemical treatment was assessed through the measurement of growth inhibition of green algae (Scenedesmus vacualatus) and duckweed (Lemna minor). Toxicity of SMR, STZ, SMN solutions before and after electrochemical oxidation and SDM solution after the process in L. minor test was observed. No significant toxicity of studied SNs was observed in algae test.

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

    Science.gov (United States)

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

    2011-01-01

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

  9. Regulation of cholesterol metabolism: An IDOL-dependent pathway to degrade the LDL-receptor

    NARCIS (Netherlands)

    Sorrentino, V.

    2014-01-01

    The central theme of this thesis is the functional and molecular characterization of the LXR-IDOL-LDLR nexus, a novel post-translational regulative pathway of the LDL receptor, complementary to the SREBP-driven transcriptional control of LDLR for sterol regulation of LDL uptake in the cell. In

  10. Bifurcated Degradative Pathway of 3-Sulfolactate in Roseovarius nubinhibens ISM via Sulfoacetaldehyde Acetyltransferase and (S)-Cysteate Sulfolyase ▿ †

    Science.gov (United States)

    Denger, Karin; Mayer, Jutta; Buhmann, Matthias; Weinitschke, Sonja; Smits, Theo H. M.; Cook, Alasdair M.

    2009-01-01

    Data from the genome sequence of the aerobic, marine bacterium Roseovarius nubinhibens ISM were interpreted such that 3-sulfolactate would be degraded as a sole source of carbon and energy for growth via a novel bifurcated pathway including two known desulfonative enzymes, sulfoacetaldehyde acetyltransferase (EC 2.3.3.15) (Xsc) and cysteate sulfo-lyase (EC 4.4.1.25) (CuyA). Strain ISM utilized sulfolactate quantitatively with stoichiometric excretion of the sulfonate sulfur as sulfate. A combination of enzyme assays, analytical chemistry, enzyme purification, peptide mass fingerprinting, and reverse transcription-PCR data supported the presence of an inducible, tripartite sulfolactate uptake system (SlcHFG), and a membrane-bound sulfolactate dehydrogenase (SlcD) which generated 3-sulfopyruvate, the point of bifurcation. 3-Sulfopyruvate was in part decarboxylated by 3-sulfopyruvate decarboxylase (EC 4.1.1.79) (ComDE), which was purified. The sulfoacetaldehyde that was formed was desulfonated by Xsc, which was identified, and the acetyl phosphate was converted to acetyl-coenzyme A by phosphate acetyltransferase (Pta). The other portion of the 3-sulfopyruvate was transaminated to (S)-cysteate, which was desulfonated by CuyA, which was identified. The sulfite that was formed was presumably exported by CuyZ (TC 9.B.7.1.1 in the transport classification system), and a periplasmic sulfite dehydrogenase is presumed. Bioinformatic analyses indicated that transporter SlcHFG is rare but that SlcD is involved in three different combinations of pathways, the bifurcated pathway shown here, via CuyA alone, and via Xsc alone. This novel pathway involves ComDE in biodegradation, whereas it was discovered in the biosynthesis of coenzyme M. The different pathways of desulfonation of sulfolactate presumably represent final steps in the biodegradation of sulfoquinovose (and exudates derived from it) in marine and aquatic environments. PMID:19581363

  11. The deep-subsurface sulfate reducer Desulfotomaculum kuznetsovii employs two methanol-degrading pathways

    OpenAIRE

    Sousa, Diana Z.; Visser, Michael; Gelder, Van, Antonie H.; Boeren, Sjef; Pieterse, Mervin M.; Pinkse, Martijn W.H.; Verhaert, Peter D.E.M.; Vogt, Carsten; Franke, Steffi; Kümmel, Steffen; Stams, Alfons J.M.

    2018-01-01

    Methanol is generally metabolized through a pathway initiated by a cobalamine-containing methanol methyltransferase by anaerobic methylotrophs (such as methanogens and acetogens), or through oxidation to formaldehyde using a methanol dehydrogenase by aerobes. Methanol is an important substrate in deep-subsurface environments, where thermophilic sulfate-reducing bacteria of the genus Desulfotomaculum have key roles. Here, we study the methanol metabolism of Desulfotomaculum kuznetsovii strain ...

  12. Bioremediation of soil polluted with crude oil and its derivatives: Microorganisms, degradation pathways, technologies

    Directory of Open Access Journals (Sweden)

    Beškoski Vladimir P.

    2012-01-01

    Full Text Available The contamination of soil and water with petroleum and its products occurs due to accidental spills during exploitation, transport, processing, storing and use. In order to control the environmental risks caused by petroleum products a variety of techniques based on physical, chemical and biological methods have been used. Biological methods are considered to have a comparative advantage as cost effective and environmentally friendly technologies. Bioremediation, defined as the use of biological systems to destroy and reduce the concentrations of hazardous waste from contaminated sites, is an evolving technology for the removal and degradation of petroleum hydrocarbons as well as industrial solvents, phenols and pesticides. Microorganisms are the main bioremediation agents due to their diverse metabolic capacities. In order to enhance the rate of pollutant degradation the technology optimizes the conditions for the growth of microorganisms present in soil by aeration, nutrient addition and, if necessary, by adding separately prepared microorganisms cultures. The other factors that influence the efficiency of process are temperature, humidity, presence of surfactants, soil pH, mineral composition, content of organic substance of soil as well as type and concentration of contaminant. This paper presents a review of our ex situ bioremediation procedures successfully implemented on the industrial level. This technology was used for treatment of soils contaminated by crude oil and its derivatives originated from refinery as well as soils polluted with oil fuel and transformer oil.

  13. Metagenomic Analysis of Hot Springs in Central India Reveals Hydrocarbon Degrading Thermophiles and Pathways Essential for Survival in Extreme Environments.

    Science.gov (United States)

    Saxena, Rituja; Dhakan, Darshan B; Mittal, Parul; Waiker, Prashant; Chowdhury, Anirban; Ghatak, Arundhuti; Sharma, Vineet K

    2016-01-01

    Extreme ecosystems such as hot springs are of great interest as a source of novel extremophilic species, enzymes, metabolic functions for survival and biotechnological products. India harbors hundreds of hot springs, the majority of which are not yet explored and require comprehensive studies to unravel their unknown and untapped phylogenetic and functional diversity. The aim of this study was to perform a large-scale metagenomic analysis of three major hot springs located in central India namely, Badi Anhoni, Chhoti Anhoni, and Tattapani at two geographically distinct regions (Anhoni and Tattapani), to uncover the resident microbial community and their metabolic traits. Samples were collected from seven distinct sites of the three hot spring locations with temperature ranging from 43.5 to 98°C. The 16S rRNA gene amplicon sequencing of V3 hypervariable region and shotgun metagenome sequencing uncovered a unique taxonomic and metabolic diversity of the resident thermophilic microbial community in these hot springs. Genes associated with hydrocarbon degradation pathways, such as benzoate, xylene, toluene, and benzene were observed to be abundant in the Anhoni hot springs (43.5-55°C), dominated by Pseudomonas stutzeri and Acidovorax sp., suggesting the presence of chemoorganotrophic thermophilic community with the ability to utilize complex hydrocarbons as a source of energy. A high abundance of genes belonging to methane metabolism pathway was observed at Chhoti Anhoni hot spring, where methane is reported to constitute >80% of all the emitted gases, which was marked by the high abundance of Methylococcus capsulatus . The Tattapani hot spring, with a high-temperature range (61.5-98°C), displayed a lower microbial diversity and was primarily dominated by a nitrate-reducing archaeal species Pyrobaculum aerophilum . A higher abundance of cell metabolism pathways essential for the microbial survival in extreme conditions was observed at Tattapani. Taken together, the

  14. M2-like macrophages are responsible for collagen degradation through a mannose receptor-mediated pathway

    DEFF Research Database (Denmark)

    Madsen, Daniel H; Leonard, Daniel; Masedunskas, Andrius

    2013-01-01

    Tissue remodeling processes critically depend on the timely removal and remodeling of preexisting collagen scaffolds. Nevertheless, many aspects related to the turnover of this abundant extracellular matrix component in vivo are still incompletely understood. We therefore took advantage of recent...... advances in optical imaging to develop an assay to visualize collagen turnover in situ and identify cell types and molecules involved in this process. Collagen introduced into the dermis of mice underwent cellular endocytosis in a partially matrix metalloproteinase-dependent manner and was subsequently...... routed to lysosomes for complete degradation. Collagen uptake was predominantly executed by a quantitatively minor population of M2-like macrophages, whereas more abundant Col1a1-expressing fibroblasts and Cx3cr1-expressing macrophages internalized collagen at lower levels. Genetic ablation...

  15. Biochemical and structural characterization of Klebsiella pneumoniae oxamate amidohydrolase in the uric acid degradation pathway

    Energy Technology Data Exchange (ETDEWEB)

    Hicks, Katherine A.; Ealick, Steven E.

    2016-05-25

    HpxW from the ubiquitous pathogenKlebsiella pneumoniaeis involved in a novel uric acid degradation pathway downstream from the formation of oxalurate. Specifically, HpxW is an oxamate amidohydrolase which catalyzes the conversion of oxamate to oxalate and is a member of the Ntn-hydrolase superfamily. HpxW is autoprocessed from an inactive precursor to form a heterodimer, resulting in a 35.5 kDa α subunit and a 20 kDa β subunit. Here, the structure of HpxW is presented and the substrate complex is modeled. In addition, the steady-state kinetics of this enzyme and two active-site variants were characterized. These structural and biochemical studies provide further insight into this class of enzymes and allow a mechanism for catalysis consistent with other members of the Ntn-hydrolase superfamily to be proposed.

  16. Degradation Pathways for Geogenic Volatile Organic Compounds (VOCs) in Soil Gases from the Solfatara Crater (Campi Flegrei, Southern Italy).

    Science.gov (United States)

    Tassi, F.; Venturi, S.; Cabassi, J.; Capecchiacci, F.; Nisi, B., Sr.; Vaselli, O.

    2014-12-01

    The chemical composition of volatile organic compounds (VOCs) in soil gases from the Solfatara crater (Campi Flegrei, Southern Italy) was analyzed to investigate the effects of biogeochemical processes occurring within the crater soil on gases discharged from the hydrothermal reservoir and released into the atmosphere through diffuse degassing. In this system, two fumarolic vents (namely Bocca Grande and Bocca Nuova) are the preferential pathways for hydrothermal fluid uprising. For our goal, the chemistry of VOCs discharged from these sites were compared to that of soil gases. Our results highlighted that C4-C9 alkanes, alkenes, S-bearing compounds and alkylated aromatics produced at depth were the most prone to degradation processes, such as oxidation-reduction and hydration-dehydration reactions, as well as to microbial activity. Secondary products, which were enriched in sites characterized by low soil gas fluxes, mostly consisted of aldheydes, ketons, esters, ethers, organic acids and, subordinately, alcohols. Benzene, phenol and hydrofluorocarbons (HCFCs) produced at depth were able to transit through the soil almost undisturbed, independently on the emission rate of diffuse degassing. The presence of cyclics was possibly related to an independent low-temperature VOC source, likely within sedimentary formations overlying the hydrothermal reservoir. Chlorofluorocarbons (CFCs) were possibly due to air contamination. This study demonstrated the strict control of biogeochemical processes on the behaviour of hydrothermal VOCs that, at least at a local scale, may have a significant impact on air quality. Laboratory experiments conducted at specific chemical-physical conditions and in presence of different microbial populations may provide useful information for the reconstruction of the degradation pathways controlling fate and behaviour of VOCs in the soil.

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

    Directory of Open Access Journals (Sweden)

    Alexia Comte

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

  18. Relative Contribution of Prolyl Hydroxylase-Dependent and -Independent Degradation of HIF-1alpha by Proteasomal Pathways in Cerebral Ischemia

    Directory of Open Access Journals (Sweden)

    Yomna Badawi

    2017-05-01

    Full Text Available Hypoxia inducible factor-1 (HIF-1 is a key regulator in hypoxia and can determine the fate of brain cells during ischemia. However, the mechanism of HIF-1 regulation is still not fully understood in ischemic brains. We tested a hypothesis that both the 26S and the 20S proteasomal pathways were involved in HIF-1α degradation under ischemic conditions. Using in vitro ischemic model (oxygen and glucose deprivation and a mouse model of middle cerebral artery occlusion, we tested effects of inhibitors of proteasomes and prolyl hydroxylase (PHD on HIF-1α stability and brain injury in cerebral ischemia. We observed that 30 and 60 min of oxygen-glucose deprivation significantly increased the 20S proteasomal activity. We demonstrated that proteasome inhibitors increased HIF-1α stabilization and cell viability and were more effective than PHD inhibitors in primary cultured cortical neurons exposed to oxygen and glucose deprivation. Furthermore, the administration of the proteasome inhibitor, epoxomicin, to mice resulted in smaller infarct size and brain edema than a PHD inhibitor. Our results indicate that 20S proteasomes are involved in HIF-1α degradation in ischemic neurons and that proteasomal inhibition provides more HIF-1α stabilization and neuroprotection than PHD inhibition in cerebral ischemia.

  19. Microbial oil-degradation under mild hydrostatic pressure (10 MPa): which pathways are impacted in piezosensitive hydrocarbonoclastic bacteria?

    KAUST Repository

    Scoma, Alberto

    2016-03-29

    Oil spills represent an overwhelming carbon input to the marine environment that immediately impacts the sea surface ecosystem. Microbial communities degrading the oil fraction that eventually sinks to the seafloor must also deal with hydrostatic pressure, which linearly increases with depth. Piezosensitive hydrocarbonoclastic bacteria are ideal candidates to elucidate impaired pathways following oil spills at low depth. In the present paper, we tested two strains of the ubiquitous Alcanivorax genus, namely A. jadensis KS_339 and A. dieselolei KS_293, which is known to rapidly grow after oil spills. Strains were subjected to atmospheric and mild pressure (0.1, 5 and 10 MPa, corresponding to a depth of 0, 500 and 1000 m, respectively) providing n-dodecane as sole carbon source. Pressures equal to 5 and 10 MPa significantly lowered growth yields of both strains. However, in strain KS_293 grown at 10 MPa CO2 production per cell was not affected, cell integrity was preserved and PO43− uptake increased. Analysis of its transcriptome revealed that 95% of its genes were downregulated. Increased transcription involved protein synthesis, energy generation and respiration pathways. Interplay between these factors may play a key role in shaping the structure of microbial communities developed after oil spills at low depth and limit their bioremediation potential.

  20. Thermal decomposition of biphenyl (1963)

    International Nuclear Information System (INIS)

    Clerc, M.

    1962-06-01

    The rates of formation of the decomposition products of biphenyl; hydrogen, methane, ethane, ethylene, as well as triphenyl have been measured in the vapour and liquid phases at 460 deg. C. The study of the decomposition products of biphenyl at different temperatures between 400 and 460 deg. C has provided values of the activation energies of the reactions yielding the main products of pyrolysis in the vapour phase. Product and Activation energy: Hydrogen 73 ± 2 kCal/Mole; Benzene 76 ± 2 kCal/Mole; Meta-triphenyl 53 ± 2 kCal/Mole; Biphenyl decomposition 64 ± 2 kCal/Mole; The rate of disappearance of biphenyl is only very approximately first order. These results show the major role played at the start of the decomposition by organic impurities which are not detectable by conventional physico-chemical analysis methods and the presence of which accelerates noticeably the decomposition rate. It was possible to eliminate these impurities by zone-melting carried out until the initial gradient of the formation curves for the products became constant. The composition of the high-molecular weight products (over 250) was deduced from the mean molecular weight and the dosage of the aromatic C - H bonds by infrared spectrophotometry. As a result the existence in tars of hydrogenated tetra, penta and hexaphenyl has been demonstrated. (author) [fr

  1. Concentrations of Polychlorinated Biphenyls (PCBs ...

    African Journals Online (AJOL)

    MICHAEL

    ABSTRACT: Concentrations of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and polybrominated diphenyl ethers (PBDEs) were examined as a function of depth in killer whale (Orcinus orca) blubber samples. Lipid-normalized concentrations of PCBs, PCDD/Fs, and ...

  2. Oxidation of indometacin by ferrate (VI): kinetics, degradation pathways, and toxicity assessment.

    Science.gov (United States)

    Huang, Junlei; Wang, Yahui; Liu, Guoguang; Chen, Ping; Wang, Fengliang; Ma, Jingshuai; Li, Fuhua; Liu, Haijin; Lv, Wenying

    2017-04-01

    The oxidation of indometacin (IDM) by ferrate(VI) (Fe(VI)) was investigated to determine the reaction kinetics, transformation products, and changes in toxicity. The reaction between IDM and Fe(VI) followed first-order kinetics with respect to each reactant. The apparent second-order rate constants (k app ) decreased from 9.35 to 6.52 M -1  s -1 , as the pH of the solution increased from 7.0 to 10.0. The pH dependence of k app might be well explained by considering the species-specific rate constants of the reactions of IDM with Fe(VI). Detailed product studies using liquid chromatography-tandem mass spectrometry (LC-MS/MS) indicated that the oxidation products were primarily derived from the hydrolysis of amide linkages, the addition of hydroxyl groups, and electrophilic oxidation. The toxicity of the oxidation products was evaluated using the Microtox test, which indicated that transformation products exhibited less toxicity to the Vibrio fischeri bacteria. Quantitative structure-activity relationship (QSAR) analysis calculated by the ecological structure activity relationship (ECOSAR) revealed that all of the identified products exhibited lower acute and chronic toxicity than the parent pharmaceutical for fish, daphnid, and green algae. Furthermore, Fe(VI) was effective in the degradation IDM in water containing carbonate ions or fulvic acid (FA), and in lake water samples; however, higher Fe(VI) dosages would be required to completely remove IDM in lake water in contrast to deionized water.

  3. Nitrate-induced photodegradation of atenolol in aqueous solution: kinetics, toxicity and degradation pathways.

    Science.gov (United States)

    Ji, Yuefei; Zeng, Chao; Ferronato, Corinne; Chovelon, Jean-Marc; Yang, Xi

    2012-07-01

    The extensive utilization of β-blockers worldwide led to frequent detection in natural water. In this study the photolysis behavior of atenolol (ATL) and toxicity of its photodegradation products were investigated in the presence of nitrate ions. The results showed that ATL photodegradation followed pseudo-first-order kinetics upon simulated solar irradiation. The photodegradation was found to be dependent on nitrate concentration and increasing the nitrate from 0.5 mML(-1) to 10 mML(-1) led to the enhancement of rate constant from 0.00101 min(-1) to 0.00716 min(-1). Hydroxyl radical was determined to play a key role in the photolysis process by using isopropanol as molecular probe. Increasing the solution pH from 4.8 to 10.4, the photodegradation rate slightly decreased from 0.00246 min(-1) to 0.00195 min(-1), probably due to pH-dependent effect of nitrate-induced .OH formation. Bicarbonate decreased the photodegradation of ATL in the presence of nitrate ions mainly through pH effect, while humic substance inhibited the photodegradation via both attenuating light and competing radicals. Upon irradiation for 240 min, only 10% reduction of total organic carbon (TOC) can be achieved in spite of 72% transformation rate of ATL, implying a majority of ATL transformed into intermediate products rather than complete mineralization. The main photoproducts of ATL were identified by using solid phase extraction-liquid chromatography-mass spectrometry (SPE-LC-MS) techniques and possible nitrate-induced photodegradation pathways were proposed. The toxicity of the phototransformation products was evaluated using aquatic species Daphnia magna, and the results revealed that photodegradation was an effective mechanism for ATL toxicity reduction in natural waters. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Methylmercury degradation and exposure pathways in streams and wetlands impacted by historical mining

    International Nuclear Information System (INIS)

    Donovan, Patrick M.; Blum, Joel D.; Singer, Michael Bliss; Marvin-DiPasquale, Mark; Tsui, Martin T.K.

    2016-01-01

    Monomethyl mercury (MMHg) and total mercury (THg) concentrations and Hg stable isotope ratios (δ 202 Hg and Δ 199 Hg) were measured in sediment and aquatic organisms from Cache Creek (California Coast Range) and Yolo Bypass (Sacramento Valley). Cache Creek sediment had a large range in THg (87 to 3870 ng/g) and δ 202 Hg (− 1.69 to − 0.20‰) reflecting the heterogeneity of Hg mining sources in sediment. The δ 202 Hg of Yolo Bypass wetland sediment suggests a mixture of high and low THg sediment sources. Relationships between %MMHg (the percent ratio of MMHg to THg) and Hg isotope values (δ 202 Hg and Δ 199 Hg) in fish and macroinvertebrates were used to identify and estimate the isotopic composition of MMHg. Deviation from linear relationships was found between %MMHg and Hg isotope values, which is indicative of the bioaccumulation of isotopically distinct pools of MMHg. The isotopic composition of pre-photodegraded MMHg (i.e., subtracting fractionation from photochemical reactions) was estimated and contrasting relationships were observed between the estimated δ 202 Hg of pre-photodegraded MMHg and sediment IHg. Cache Creek had mass dependent fractionation (MDF; δ 202 Hg) of at least − 0.4‰ whereas Yolo Bypass had MDF of + 0.2 to + 0.5‰. This result supports the hypothesis that Hg isotope fractionation between IHg and MMHg observed in rivers (− MDF) is unique compared to + MDF observed in non-flowing water environments such as wetlands, lakes, and the coastal ocean. - Highlights: • Mercury isotope ratios were measured in sediment and biota from Central California. • The isotopic composition of MMHg was estimated in streams and wetlands. • Mercury isotopes suggest multiple exposure pathways in these habitats. • Mass dependent fractionation between IHg and MMHg is different in streams.

  5. Methylmercury degradation and exposure pathways in streams and wetlands impacted by historical mining

    Energy Technology Data Exchange (ETDEWEB)

    Donovan, Patrick M., E-mail: pmdon@umich.edu [University of Michigan, Department of Earth and Environmental Sciences, 1100 N., University Ave., Ann Arbor, MI 48109 (United States); Blum, Joel D. [University of Michigan, Department of Earth and Environmental Sciences, 1100 N., University Ave., Ann Arbor, MI 48109 (United States); Singer, Michael Bliss [University of St Andrews, Department of Earth and Environmental Sciences, North St., St. Andrews, KY16 9AL (United Kingdom); Earth Research Institute, University of California Santa Barbara, Santa Barbara, CA, 91306 (United States); Marvin-DiPasquale, Mark [U.S. Geological Survey, Menlo Park, CA (United States); Tsui, Martin T.K. [Department of Biology, University of North Carolina at Greensboro, Greensboro, NC 27402 (United States)

    2016-10-15

    Monomethyl mercury (MMHg) and total mercury (THg) concentrations and Hg stable isotope ratios (δ{sup 202}Hg and Δ{sup 199}Hg) were measured in sediment and aquatic organisms from Cache Creek (California Coast Range) and Yolo Bypass (Sacramento Valley). Cache Creek sediment had a large range in THg (87 to 3870 ng/g) and δ{sup 202}Hg (− 1.69 to − 0.20‰) reflecting the heterogeneity of Hg mining sources in sediment. The δ{sup 202}Hg of Yolo Bypass wetland sediment suggests a mixture of high and low THg sediment sources. Relationships between %MMHg (the percent ratio of MMHg to THg) and Hg isotope values (δ{sup 202}Hg and Δ{sup 199}Hg) in fish and macroinvertebrates were used to identify and estimate the isotopic composition of MMHg. Deviation from linear relationships was found between %MMHg and Hg isotope values, which is indicative of the bioaccumulation of isotopically distinct pools of MMHg. The isotopic composition of pre-photodegraded MMHg (i.e., subtracting fractionation from photochemical reactions) was estimated and contrasting relationships were observed between the estimated δ{sup 202}Hg of pre-photodegraded MMHg and sediment IHg. Cache Creek had mass dependent fractionation (MDF; δ{sup 202}Hg) of at least − 0.4‰ whereas Yolo Bypass had MDF of + 0.2 to + 0.5‰. This result supports the hypothesis that Hg isotope fractionation between IHg and MMHg observed in rivers (− MDF) is unique compared to + MDF observed in non-flowing water environments such as wetlands, lakes, and the coastal ocean. - Highlights: • Mercury isotope ratios were measured in sediment and biota from Central California. • The isotopic composition of MMHg was estimated in streams and wetlands. • Mercury isotopes suggest multiple exposure pathways in these habitats. • Mass dependent fractionation between IHg and MMHg is different in streams.

  6. Metagenomic Analysis of Hot Springs in Central India Reveals Hydrocarbon Degrading Thermophiles and Pathways Essential for Survival in Extreme Environments

    Science.gov (United States)

    Saxena, Rituja; Dhakan, Darshan B.; Mittal, Parul; Waiker, Prashant; Chowdhury, Anirban; Ghatak, Arundhuti; Sharma, Vineet K.

    2017-01-01

    Extreme ecosystems such as hot springs are of great interest as a source of novel extremophilic species, enzymes, metabolic functions for survival and biotechnological products. India harbors hundreds of hot springs, the majority of which are not yet explored and require comprehensive studies to unravel their unknown and untapped phylogenetic and functional diversity. The aim of this study was to perform a large-scale metagenomic analysis of three major hot springs located in central India namely, Badi Anhoni, Chhoti Anhoni, and Tattapani at two geographically distinct regions (Anhoni and Tattapani), to uncover the resident microbial community and their metabolic traits. Samples were collected from seven distinct sites of the three hot spring locations with temperature ranging from 43.5 to 98°C. The 16S rRNA gene amplicon sequencing of V3 hypervariable region and shotgun metagenome sequencing uncovered a unique taxonomic and metabolic diversity of the resident thermophilic microbial community in these hot springs. Genes associated with hydrocarbon degradation pathways, such as benzoate, xylene, toluene, and benzene were observed to be abundant in the Anhoni hot springs (43.5–55°C), dominated by Pseudomonas stutzeri and Acidovorax sp., suggesting the presence of chemoorganotrophic thermophilic community with the ability to utilize complex hydrocarbons as a source of energy. A high abundance of genes belonging to methane metabolism pathway was observed at Chhoti Anhoni hot spring, where methane is reported to constitute >80% of all the emitted gases, which was marked by the high abundance of Methylococcus capsulatus. The Tattapani hot spring, with a high-temperature range (61.5–98°C), displayed a lower microbial diversity and was primarily dominated by a nitrate-reducing archaeal species Pyrobaculum aerophilum. A higher abundance of cell metabolism pathways essential for the microbial survival in extreme conditions was observed at Tattapani. Taken together

  7. Aqueous photochemical degradation of hydroxylated PAHs: Kinetics, pathways, and multivariate effects of main water constituents

    Energy Technology Data Exchange (ETDEWEB)

    Ge, Linke; Na, Guangshui [Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, Dalian 116023 (China); Chen, Chang-Er [Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ (United Kingdom); Li, Jun [Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, Dalian 116023 (China); College of Marine Science, Shanghai Ocean University, Shanghai 201306 (China); Ju, Maowei; Wang, Ying; Li, Kai [Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, Dalian 116023 (China); Zhang, Peng, E-mail: pzhang@nmemc.org.cn [Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, Dalian 116023 (China); Yao, Ziwei [Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, Dalian 116023 (China)

    2016-03-15

    PAHs. • Hydroxylated PAHs intrinsically photodegrade fast in sunlit surface waters. • Reaction types and transformation pathways of 9-Hydroxyfluorene were clarified. • Photolysis kinetics was affected by multivariate effects of main water constituents. • The photomodified toxicity of 9-Hydroxyfluorene was examined using Vibrio fischeri.

  8. Degradation of γ-HCH spiked soil using stabilized Pd/Fe0 bimetallic nanoparticles: Pathways, kinetics and effect of reaction conditions

    International Nuclear Information System (INIS)

    Singh, Ritu; Misra, Virendra; Mudiam, Mohana Krishna Reddy; Chauhan, Lalit Kumar Singh; Singh, Rana Pratap

    2012-01-01

    Highlights: ► This study explores the potential of CMC-Pd/nFe 0 to degrade γ-HCH in spiked soil. ► Sorption–desorption characteristics and partitioning of γ-HCH is investigated. ► Three degradation pathways has been proposed and discussed. ► γ-HCH degradation mechanism and kinetics is elucidated. ► Activation energy reveals that γ-HCH degradation is a surface mediated reaction. - Abstract: This study investigates the degradation pathway of gamma-hexachlorocyclohexane (γ-HCH) in spiked soil using carboxymethyl cellulose stabilized Pd/Fe 0 bimetallic nanoparticles (CMC-Pd/nFe 0 ). GC–MS analysis of γ-HCH degradation products showed the formation of pentachlorocyclohexene, tri- and di-chlorobenzene as intermediate products while benzene was formed as the most stable end product. On the basis of identified intermediates and final products, degradation pathway of γ-HCH has been proposed. Batch studies showed complete γ-HCH degradation at a loading of 0.20 g/L CMC-Pd/nFe 0 within 6 h of incubation. The surface area normalized rate constant (k SA ) was found to be 7.6 × 10 −2 L min −1 m −2 . CMC-Pd/nFe 0 displayed ∼7-fold greater efficiency for γ-HCH degradation in comparison to Fe 0 nanoparticles (nFe 0 ), synthesized without CMC and Pd. Further studies showed that increase in CMC-Pd/nFe 0 loading and reaction temperature facilitates γ-HCH degradation, whereas a declining trend in degradation was noticed with the increase in pH, initial γ-HCH concentration and in the presence of cations. The data on activation energy (33.7 kJ/mol) suggests that γ-HCH degradation is a surface mediated reaction. The significance of the study with respect to remediation of γ-HCH contaminated soil using CMC-Pd/nFe 0 has been discussed.

  9. The type II collagen fragments Helix-II and CTX-II reveal different enzymatic pathways of human cartilage collagen degradation

    DEFF Research Database (Denmark)

    Charni-Ben Tabassi, N; Desmarais, S; Jensen, Anne-Christine Bay

    2008-01-01

    OBJECTIVE: Cartilage degradation in osteoarthritis (OA) generates the type II collagen fragments, Helix-II and CTX-II that can be used as clinical biological markers. Helix-II and C-telopeptide of type II collagen (CTX-II) levels are associated independently with progression of OA suggesting...... that they may be generated through different collagenolytic pathways. In this study we analyzed the release of Helix-II and CTX-II from human cartilage collagen by the proteinases reported to play a role in cartilage degradation. METHODS: In vitro, human articular cartilage extract was incubated with activated...... pathways. Helix-II and CTX-II alone reflect only partially overall cartilage collagen degradation. These findings may explain why these two biological markers could provide complementary information on disease progression in OA....

  10. Dysregulation of protein degradation pathways may mediate the liver injury and phospholipidosis associated with a cationic amphiphilic antibiotic drug

    Energy Technology Data Exchange (ETDEWEB)

    Mosedale, Merrie [Hamner-University of North Carolina Institute for Drug Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, NC 27709 (United States); Wu, Hong [Drug Safety Research and Development, Pfizer Global Research and Development, Groton, CT06340 (United States); Kurtz, C. Lisa [Hamner-University of North Carolina Institute for Drug Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, NC 27709 (United States); Schmidt, Stephen P. [Drug Safety Research and Development, Pfizer Global Research and Development, Groton, CT06340 (United States); Adkins, Karissa, E-mail: Karissa.Adkins@pfizer.com [Drug Safety Research and Development, Pfizer Global Research and Development, Groton, CT06340 (United States); Harrill, Alison H. [Hamner-University of North Carolina Institute for Drug Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, NC 27709 (United States); University of Arkansas for Medical Sciences, Little Rock, AR72205 (United States)

    2014-10-01

    A large number of antibiotics are known to cause drug-induced liver injury in the clinic; however, interpreting clinical risk is not straightforward owing to a lack of predictivity of the toxicity by standard preclinical species and a poor understanding of the mechanisms of toxicity. An example is PF-04287881, a novel ketolide antibiotic that caused elevations in liver function tests in Phase I clinical studies. In this study, a mouse diversity panel (MDP), comprised of 34 genetically diverse, inbred mouse strains, was utilized to model the toxicity observed with PF-04287881 treatment and investigate potential mechanisms that may mediate the liver response. Significant elevations in serum alanine aminotransferase (ALT) levels in PF-04287881-treated animals relative to vehicle-treated controls were observed in the majority (88%) of strains tested following a seven day exposure. The average fold elevation in ALT varied by genetic background and correlated with microscopic findings of hepatocellular hypertrophy, hepatocellular single cell necrosis, and Kupffer cell vacuolation (confirmed as phospholipidosis) in the liver. Global liver mRNA expression was evaluated in a subset of four strains to identify transcript and pathway differences that distinguish susceptible mice from resistant mice in the context of PF-04287881 treatment. The protein ubiquitination pathway was highly enriched among genes associated with PF-04287881-induced hepatocellular necrosis. Expression changes associated with PF-04287881-induced phospholipidosis included genes involved in drug transport, phospholipid metabolism, and lysosomal function. The findings suggest that perturbations in genes involved in protein degradation leading to accumulation of oxidized proteins may mediate the liver injury induced by this drug. - Highlights: • Identified susceptible and resistant mouse strains to liver injury induced by a CAD • Liver injury characterized by single cell necrosis, and phospholipidosis

  11. Dysregulation of protein degradation pathways may mediate the liver injury and phospholipidosis associated with a cationic amphiphilic antibiotic drug

    International Nuclear Information System (INIS)

    Mosedale, Merrie; Wu, Hong; Kurtz, C. Lisa; Schmidt, Stephen P.; Adkins, Karissa; Harrill, Alison H.

    2014-01-01

    A large number of antibiotics are known to cause drug-induced liver injury in the clinic; however, interpreting clinical risk is not straightforward owing to a lack of predictivity of the toxicity by standard preclinical species and a poor understanding of the mechanisms of toxicity. An example is PF-04287881, a novel ketolide antibiotic that caused elevations in liver function tests in Phase I clinical studies. In this study, a mouse diversity panel (MDP), comprised of 34 genetically diverse, inbred mouse strains, was utilized to model the toxicity observed with PF-04287881 treatment and investigate potential mechanisms that may mediate the liver response. Significant elevations in serum alanine aminotransferase (ALT) levels in PF-04287881-treated animals relative to vehicle-treated controls were observed in the majority (88%) of strains tested following a seven day exposure. The average fold elevation in ALT varied by genetic background and correlated with microscopic findings of hepatocellular hypertrophy, hepatocellular single cell necrosis, and Kupffer cell vacuolation (confirmed as phospholipidosis) in the liver. Global liver mRNA expression was evaluated in a subset of four strains to identify transcript and pathway differences that distinguish susceptible mice from resistant mice in the context of PF-04287881 treatment. The protein ubiquitination pathway was highly enriched among genes associated with PF-04287881-induced hepatocellular necrosis. Expression changes associated with PF-04287881-induced phospholipidosis included genes involved in drug transport, phospholipid metabolism, and lysosomal function. The findings suggest that perturbations in genes involved in protein degradation leading to accumulation of oxidized proteins may mediate the liver injury induced by this drug. - Highlights: • Identified susceptible and resistant mouse strains to liver injury induced by a CAD • Liver injury characterized by single cell necrosis, and phospholipidosis

  12. Stability-indicating assay method for determination of actarit, its process related impurities and degradation products: Insight into stability profile and degradation pathways☆

    Directory of Open Access Journals (Sweden)

    A. Abiramasundari

    2014-12-01

    Full Text Available The stability of the drug actarit was studied under different stress conditions like hydrolysis (acid, alkaline and neutral, oxidation, photolysis and thermal degradation as recommended by International Conference on Harmonization (ICH guidelines. Drug was found to be unstable in acidic, basic and photolytic conditions and produced a common degradation product while oxidative stress condition produced three additional degradation products. Drug was impassive to neutral hydrolysis, dry thermal and accelerated stability conditions. Degradation products were identified, isolated and characterized by different spectroscopic analyses. Drug and the degradation products were synthesized by a new route using green chemistry. The chromatographic separation of the drug and its impurities was achieved in a phenomenex luna C18 column employing a step gradient elution by high performance liquid chromatography coupled to photodiode array and mass spectrometry detectors (HPLC–PDA–MS. A specific and sensitive stability-indicating assay method for the simultaneous determination of the drug actarit, its process related impurities and degradation products was developed and validated. Keywords: Actarit, Forced degradation, Stability-indicating assay method

  13. Evaluating tetracycline degradation pathway and intermediate toxicity during the electrochemical oxidation over a Ti/Ti4O7anode.

    Science.gov (United States)

    Wang, Jianbing; Zhi, Dan; Zhou, Hao; He, Xuwen; Zhang, Dayi

    2018-03-12

    min due to further transformation of TC and intermediates. By comprehensively analyzing the influential factors and complete degradation pathway of TC electrochemical oxidation on the Ti/Ti 4 O 7 anode, our research provides deeper insights into the risk assessment of intermediates and their toxicity, assigning new perspectives for practical electrochemical oxidation to effectively eliminate the amount and toxicity of TC and other antibiotics in wastewater. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. Anaerobic degradation of glycol ether-ethanol mixtures using EGSB and hybrid reactors: Performance comparison and ether cleavage pathway.

    Science.gov (United States)

    Ferrero, P; San-Valero, P; Gabaldón, C; Martínez-Soria, V; Penya-Roja, J M

    2018-05-01

    The anaerobic biodegradation of ethanol-glycol ether mixtures as 1-ethoxy-2-propanol (E2P) and 1-methoxy-2-propanol (M2P), widely used in printing facilities, was investigated by means of two laboratory-scale anaerobic bioreactors at 25 o C: an expanded granular sludge bed (EGSB) reactor and an anaerobic hybrid reactor (AHR), which incorporated a packed bed to improve biomass retention. Despite AHR showed almost half of solid leakages compared to EGSB, both reactors obtained practically the same performance for the operating conditions studied with global removal efficiencies (REs) higher than 92% for organic loading rates (OLRs) as high as 54 kg of chemical oxygen demand (COD) m -3 d -1 (REs of 70% and 100% for OLRs of 10.6 and 8.3 kg COD m -3 d -1 for E2P and M2P, respectively). Identified byproducts allowed clarifying the anaerobic degradation pathways of these glycol ethers. Thus, this study shows that anaerobic scrubber can be a feasible treatment for printing emissions. Copyright © 2018 Elsevier Ltd. All rights reserved.

  15. Effects of rapid or slow body weight reduction on intramuscular protein degradation pathways during equivalent weight loss on rats.

    Science.gov (United States)

    Nonaka, Y; Urashima, S; Inai, M; Nishimura, S; Higashida, K; Terada, S

    2017-11-24

    The purpose of this study was to compare the effects of short-term fasting-induced rapid weight loss with those of slower but equivalent body weight loss induced by daily calorie restriction on muscle protein degradation pathways and muscle protein content. Male Fischer rats were subjected to either 30 % calorie restriction for 2 weeks to slowly decrease body weight (Slow) or 3-day fasting to rapidly decrease body weight by a comparable level of that of the Slow group (Rapid). The final body weights were about 15 % lower in both the Slow and Rapid groups than in the Con group (pweight of fast-twitch plantaris muscle, but not slow-twitch soleus muscle, were significantly lower in the Rapid group compared with the control rats fed ad libitum. Substantial increases in the expression ratio of autophagosomal membrane proteins (LC3-II/-I ratio) and polyubiquitinated protein concentration, used as biomarkers of autophagy-lysosome and ubiquitin-proteasome activities, respectively, were observed in the plantaris muscle of the Rapid group. Moreover, the LC3-II/-I ratio and polyubiquitinated protein concentration were negatively correlated with the total protein content and wet weight of plantaris muscle. These results suggest that short-term fasting-induced rapid body weight loss activates autophagy-lysosome and ubiquitin-proteasome systems more strongly than calorie restriction-induced slower weight reduction, resulting in muscular atrophy in fast-twitch muscle.

  16. RINL, guanine nucleotide exchange factor Rab5-subfamily, is involved in the EphA8-degradation pathway with odin.

    Directory of Open Access Journals (Sweden)

    Hiroaki Kajiho

    Full Text Available The Rab family of small guanosine triphosphatases (GTPases plays a vital role in membrane trafficking. Its active GTP-bound state is driven by guanine nucleotide-exchange factors (GEFs. Ras and Rab interactor (or Ras interaction/interference-like (RINL, which contains a conserved VPS9 domain critical for GEF action, was recently identified as a new Rab5 subfamily GEF in vitro. However, its detailed function and interacting molecules have not yet been fully elucidated. Here we found that RINL has GEF activity for the Rab5 subfamily proteins by measuring their GTP-bound forms in cultured cells. We also found that RINL interacts with odin, a member of the ankyrin-repeat and sterile-alpha motif (SAM domain-containing (Anks protein family. In addition, the Eph tyrosine kinase receptor EphA8 formed a ternary complex with both RINL and odin. Interestingly, RINL expression in cultured cells reduced EphA8 levels in a manner dependent on both its GEF activity and interaction with odin. In addition, knockdown of RINL increased EphA8 level in HeLa cells. Our findings suggest that RINL, as a GEF for Rab5 subfamily, is implicated in the EphA8-degradation pathway via its interaction with odin.

  17. Bisphenol A and Its Derivatives Induce Degradation of HIF-1alpha via the Lysosomal Pathway in Human Hepatocarcinoma Cell Line, Hep3B.

    Science.gov (United States)

    Kobayashi, Yukino; Oguro, Ami; Imaoka, Susumu

    2018-01-01

    Bisphenol A (BPA, 2,2-bis(4-hydroxyphenyl)propane), one of the phenolic compounds widely used in the manufacture of plastic and epoxy resins, is known as an endocrine disruptor. In a previous study, we found that BPA induced hypoxia inducible factor-1alpha (HIF-1alpha) degradation by dissociation from heat shock protein 90 (Hsp90). In this study, to investigate the structural requirements for degradation of HIF-1alpha, we estimated the effect of BPA derivatives (BPE, BPF, BPB, Dimethyl butylidene diphenol (DMBDP), Ethyl hexylidene diphenol (EHDP), Bishydroxyphenyl cyclohexane (BHCH), and Methyl benzylidene bisphenol (MBBP)) on HIF-1alpha protein degradation, using human hepatocarcinoma cell line, Hep3B. BPB, DMBDP, BHCH, and MBBP decreased HIF-1alpha protein levels more efficiently than BPA, but BPE, BPF, and EHDP did not affect HIF-1alpha protein levels. BPA degraded HIF-1alpha even in the presence of MG132, a proteasome inhibitor. In this study, we found that ammonium chloride (NH 4 Cl), a lysosomal enzyme inhibitor, efficiently restored the decrease in HIF-1alpha protein levels by BPA. Recent studies indicated that HIF-1alpha is degraded by the lysosomal pathway as well as the proteasomal pathway. Therefore, we investigated the levels of heat shock cognate 70 kDa protein (HSC70) protein after treatment with BPA. We found that BPA induced HSC70 protein and overexpression of HSC70 enhanced HIF-1alpha degradation in Hep3B cells. These results suggested that BPA causes the degradation of HIF-1alpha by induction of HSC70, leading lysosomal degradation of HIF-1alpha.

  18. Disruption of Nrf2/ARE signaling impairs antioxidant mechanisms and promotes cell degradation pathways in aged skeletal muscle.

    Science.gov (United States)

    Miller, Corey J; Gounder, Sellamuthu S; Kannan, Sankaranarayanan; Goutam, Karan; Muthusamy, Vasanthi R; Firpo, Matthew A; Symons, J David; Paine, Robert; Hoidal, John R; Rajasekaran, Namakkal Soorappan

    2012-06-01

    Age-associated decline in antioxidant potential and accumulation of reactive oxygen/nitrogen species are primary causes for multiple health problems, including muscular dystrophy and sarcopenia. The role of the nuclear erythroid-2-p45-related factor-2 (Nrf2) signaling has been implicated in antioxidant gene regulation. Here, we investigated the loss-of-function mechanisms for age-dependent regulation of Nrf2/ARE (Antioxidant Response Element) signaling in skeletal muscle (SM). Under basal physiological conditions, disruption of Nrf2 showed minimal effects on antioxidant defenses in young (2months) Nrf2-/- mice. Interestingly, mRNA and protein levels of NADH Quinone Oxidase-1 were dramatically (*P24months) had a significant increase in ROS along with a decrease in glutathione (GSH) levels and impaired antioxidants in Nrf2-/- when compared to WT SM. Further, disruption of Nrf2 appears to induce oxidative stress (increased ROS, HNE-positive proteins), ubiquitination and pro-apoptotic signals in the aged SM of Nrf2-/- mice. These results indicate a direct role for Nrf2/ARE signaling on impairment of antioxidants, which contribute to muscle degradation pathways upon aging. Our findings conclude that though the loss of Nrf2 is not amenable at younger age; it could severely affect the SM defenses upon aging. Thus, Nrf2 signaling might be a potential therapeutic target to protect the SM from age-dependent accumulation of ROS by rescuing redox homeostasis to prevent age-related muscle disorders such as sarcopenia and myopathy. © 2012 Elsevier B.V. All rights reserved.

  19. Accumulating evidence suggests that several AB-toxins subvert the endoplasmic reticulum-associated protein degradation pathway to enter target cells.

    Science.gov (United States)

    Hazes, B; Read, R J

    1997-09-16

    Several AB-toxins appear to have independently evolved mechanisms by which they undergo retrograde transport from the cell membrane to the endoplasmic reticulum (ER). Recent insights into ER-associated protein degradation (ERAD) now provide clues as to why these toxins have selected the ER as the site of cell entry. We propose that they disguise themselves as misfolded proteins to enter the ERAD pathway. We further link the observation that these toxins have few, if any, lysine residues to the need to escape ubiquitin-mediated protein degradation, the ultimate destination of the ERAD pathway. The actual membrane translocation step remains unclear, but studies on viral immune evasion mechanisms indicate that retrotranslocation across the ER lipid bilayer may involve SEC61. Understanding the internalization process of these toxins opens new avenues for preventing their entry into cells. In addition, this knowledge can be exploited to create protein-based pharmaceuticals that act on cytosolic targets.

  20. Intracellular collagen degradation mediated by uPARAP/Endo180 is a major pathway of extracellular matrix turnover during malignancy

    DEFF Research Database (Denmark)

    Curino, Alejandro C; Engelholm, Lars H; Yamada, Susan S

    2005-01-01

    We recently reported that uPARAP/Endo180 can mediate the cellular uptake and lysosomal degradation of collagen by cultured fibroblasts. Here, we show that uPARAP/Endo180 has a key role in the degradation of collagen during mammary carcinoma progression. In the normal murine mammary gland, uPARAP/...

  1. Cloning and expression of meta-cleavage enzyme (CarB of carbazole degradation pathway from Pseudomonas stutzeri

    Directory of Open Access Journals (Sweden)

    Ariane Leites Larentis

    2005-06-01

    Full Text Available In this work, the 1082bp PCR product corresponding to carBaBb genes that encode the heterotetrameric enzyme 2'-aminobiphenyl-2,3-diol 1,2-dioxygenase (CarB, involved in the Pseudomonas stutzeri ATCC 31258 carbazole degradation pathway, was cloned using the site-specific recombination system. Recombinant clones were confirmed by PCR, restriction enzyme digestion and sequencing. CarB dioxygenase was expressed in high levels and in active form in Escherichia coli BL21-SI using the His-tagged expression vector pDEST TM17 and salt induction for 4h.Carbazol e seus derivados são compostos nitrogenados aromáticos, presentes comumente em petróleo e potencialmente poluentes. A rota de biodegradação de carbazol a ácido antranílico em Pseudomonas sp. é composta por três enzimas responsáveis, respectivamente, pelas reações de dioxigenação angular, meta-clivagem e hidrólise. A segunda enzima da rota, 2'-aminobifenil-2,3-diol 1,2-dioxigenase (CarB, codificada por dois genes (carBa e carBb, é um heterotetrâmero com atividade catalítica na quebra do anel catecol do susbtrato na posição meta. Neste trabalho, foi clonado o produto de PCR de 1082pb correspondente aos genes carBaBb da bactéria degradadora de carbazol Pseudomonas stutzeri ATCC 31258. A estratégia de clonagem empregada foi a de recombinação sítio-específica e a construção dos plasmídeos foi confirmada por PCR, digestão com enzima de restrição e seqüenciamento. A enzima ativa foi expressa em altas concentrações em vetor pDEST TM17 com cauda de histidina e promotor T7 em Escherichia coli BL21-SI com indução por NaCl durante 4h.

  2. Production of metabolites from chloro biphenyls by resting cells of Pseudomonas strain LB400 after growth on different carbon sources

    International Nuclear Information System (INIS)

    Billingsley, K.A.; Ward, O.P.

    1999-01-01

    The transformation of polychlorinated biphenyl (PCB), when exposed to microorganisms, into chlorobenzoic acid metabolites was studied. PCBs are widely used in electrical transformers and have become widely dispersed in the environment. A proposed system for clean up of PCBs involves the combined use of anaerobic reductive dehalogenation of highly chlorinated congeners followed by aerobic degradation of moderately chlorinated PCBs, mediated by oxidative ring attack. Much of this work focused on biphenyl-grown cells, in particular Pseudomonas strain LB400 grown on biphenyl, which contains a multicomponent enzyme system. It was shown that resting cells of Pseudomonas strain LB400, grown on glycerol or glucose, could also transform purified PCB congeners and mixtures of PCBs in Aroclors, however, transformation rates were less than those observed with biphenyl-grown cells. 29 refs., 2 tabs., 2 figs

  3. Insight in the PCB-degrading functional community in long-term contaminated soil under bioremediation

    Energy Technology Data Exchange (ETDEWEB)

    Petric, Ines; Hrsak, Dubravka; Udikovic-Kolic, Nikolina [Ruder Boskovic Inst., Division for Marine and Environmental Research, Zagreb (Croatia); Fingler, Sanja [Inst. for Medical Research and Occupational Health, Zagreb (Croatia); Bru, David; Martin-Laurent, Fabrice [INRA, Univ. der Bourgogne, Soil and Environmental Microbiology, Dijon (France)

    2011-02-15

    A small-scale bioremediation assay was developed in order to get insight into the functioning of a polychlorinated biphenyl (PCB) degrading community during the time course of bioremediation treatment of a contaminated soil. The study was conducted with the aim to better understand the key mechanisms involved in PCB-removal from soils. Materials and methods Two bioremediation strategies were applied in the assay: (a) biostimulation (addition of carvone as inducer of biphenyl pathway, soya lecithin for improving PCB bioavailability, and xylose as supplemental carbon source) and (b) bioaugmentation with selected seed cultures TSZ7 or Rhodococcus sp. Z6 originating from the transformer station soil and showing substantial PCB-degrading activity. Functional PCB-degrading community was investigated by using molecular-based approaches (sequencing, qPCR) targeting bphA and bphC genes, coding key enzymes of the upper biphenyl pathway, in soil DNA extracts. In addition, kinetics of PCBs removal during the bioremediation treatment was determined using gas chromatography mass spectrometry analyses. Results and discussion bphA-based phylogeny revealed that bioremediation affected the structure of the PCB-degrading community in soils, with Rhodococcus-like bacterial populations developing as dominant members. Tracking of this population further indicated that applied bioremediation treatments led to its enrichment within the PCB-degrading community. The abundance of the PCB-degrading community, estimated by quantifying the copy number of bphA and bphC genes, revealed that it represented up to 0.3% of the total bacterial community. All bioremediation treatments were shown to enhance PCB reduction in soils, with approximately 40% of total PCBs being removed during a 1-year period. The faster PCB reduction achieved in bioaugmented soils suggested an important role of the seed cultures in bioremediation processes. Conclusions The PCBs degrading community was modified in response to

  4. Degradation mechanisms of Microcystin-LR during UV-B photolysis and UV/H2O2 processes: Byproducts and pathways.

    Science.gov (United States)

    Moon, Bo-Ram; Kim, Tae-Kyoung; Kim, Moon-Kyung; Choi, Jaewon; Zoh, Kyung-Duk

    2017-10-01

    The removal and degradation pathways of microcystin-LR (MC-LR, [M+H] +  = 995.6) in UV-B photolysis and UV-B/H 2 O 2 processes were examined using liquid chromatography-tandem mass spectrometry. The UV/H 2 O 2 process was more efficient than UV-B photolysis for MC-LR removal. Eight by-products were newly identified in the UV-B photolysis ([M+H] +  = 414.3, 417.3, 709.6, 428.9, 608.6, 847.5, 807.4, and 823.6), and eleven by-products were identified in the UV-B/H 2 O 2 process ([M+H] +  = 707.4, 414.7, 429.3, 445.3, 608.6, 1052.0, 313.4, 823.6, 357.3, 245.2, and 805.7). Most of the MC-LR by-products had lower [M+H] + values than the MC-LR itself during both processes, except for the [M+H] + value of 1052.0 during UV-B photolysis. Based on identified by-products and peak area patterns, we proposed potential degradation pathways during the two processes. Bond cleavage and intramolecular electron rearrangement by electron pair in the nitrogen atom were the major reactions during UV-B photolysis and UV-B/H 2 O 2 processes, and hydroxylation by OH radical and the adduct formation reaction between the produced by-products were identified as additional pathways during the UV-B/H 2 O 2 process. Meanwhile, the degradation by-products identified from MC-LR during UV-B/H 2 O 2 process can be further degraded by increasing H 2 O 2 dose. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Lysine-Less Variants of Spinal Muscular Atrophy SMN and SMNΔ7 Proteins Are Degraded by the Proteasome Pathway

    Directory of Open Access Journals (Sweden)

    Raúl Sánchez-Lanzas

    2017-12-01

    Full Text Available Spinal muscular atrophy is due to mutations affecting the SMN1 gene coding for the full-length protein (survival motor neuron; SMN and the SMN2 gene that preferentially generates an exon 7-deleted protein (SMNΔ7 by alternative splicing. To study SMN and SMNΔ7 degradation in the cell, we have used tagged versions at the N- (Flag or C-terminus (V5 of both proteins. Transfection of those constructs into HeLa cells and treatment with cycloheximide showed that those protein constructs were degraded. Proteasomal degradation usually requires prior lysine ubiquitylation. Surprisingly, lysine-less variants of both proteins tagged either at N- (Flag or C-terminus (V5 were also degraded. The degradation of the endogenous SMN protein, and the protein constructs mentioned above, was mediated by the proteasome, as it was blocked by lactacystin, a specific and irreversible proteasomal inhibitor. The results obtained allowed us to conclude that SMN and SMNΔ7 proteasomal degradation did not absolutely require internal ubiquitylation nor N-terminal ubiquitylation (prevented by N-terminal tagging. While the above conclusions are firmly supported by the experimental data presented, we discuss and justify the need of deep proteomic techniques for the study of SMN complex components (orphan and bound turn-over to understand the physiological relevant mechanisms of degradation of SMN and SMNΔ7 in the cell.

  6. H₃PW₁₂O₄₀/TiO₂ catalyst-induced photodegradation of bisphenol A (BPA): kinetics, toxicity and degradation pathways.

    Science.gov (United States)

    Lu, Nan; Lu, Ying; Liu, Fangyuan; Zhao, Kun; Yuan, Xing; Zhao, Yahui; Li, Yuan; Qin, Hongwei; Zhu, Jia

    2013-05-01

    A series of experiments were conducted to investigate the kinetics of bisphenol A (2,2-bis(4-hydroxyphenyl)propane, BPA) degradation using H₃PW₁₂O₄₀/TiO₂ (PW₁₂/TiO₂) composite catalyst, toxicity of BPA intermediate products and degradation pathways. The results showed that the BPA photodegradation using PW₁₂/TiO₂ catalyst followed the first-order kinetics, and under the optimal experimental conditions at H₃PW₁₂O₄₀ loading amount of 6.3%, BPA initial concentration of 5 mg L(-1), and the solution pH of 8.2, the kinetic constant was 3.7-fold larger than that of pristine TiO₂. The hydroxyl radicals derived from the electroreduction of dissolved oxygen with electrons via chain reactions was the main reactive oxygen species. According to the identified intermediates, 4-isopropanolphenol, hydroquinone, 4-hydroxybenzoic acid, and phenol, the possible BPA photodegradation pathways were proposed. Upon 12h irradiation, 77% BPA (20 mg L(-1)) was mineralized and the toxicity to Daphnia magna (D. magna) was almost disappeared, implying the strong oxidation ability of PW₁₂/TiO₂ catalyst. The studies provide important information about the BPA degradation and promote the technical development for BPA removal. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Susceptibility loci of CNOT6 in the general mRNA degradation pathway and lung cancer risk-A re-analysis of eight GWASs.

    Science.gov (United States)

    Zhou, Fei; Wang, Yanru; Liu, Hongliang; Ready, Neal; Han, Younghun; Hung, Rayjean J; Brhane, Yonathan; McLaughlin, John; Brennan, Paul; Bickeböller, Heike; Rosenberger, Albert; Houlston, Richard S; Caporaso, Neil; Landi, Maria Teresa; Brüske, Irene; Risch, Angela; Ye, Yuanqing; Wu, Xifeng; Christiani, David C; Goodman, Gary; Chen, Chu; Amos, Christopher I; Wei, Qingyi

    2017-04-01

    mRNA degradation is an important regulatory step for controlling gene expression and cell functions. Genetic abnormalities involved in mRNA degradation genes were found to be associated with cancer risks. Therefore, we systematically investigated the roles of genetic variants in the general mRNA degradation pathway in lung cancer risk. Meta-analyses were conducted using summary data from six lung cancer genome-wide association studies (GWASs) from the Transdisciplinary Research in Cancer of the Lung and additional two GWASs from Harvard University and deCODE in the International Lung Cancer Consortium. Expression quantitative trait loci analysis (eQTL) was used for in silico functional validation of the identified significant susceptibility loci. This pathway-based analysis included 6816 single nucleotide polymorphisms (SNP) in 68 genes in 14 463 lung cancer cases and 44 188 controls. In the single-locus analysis, we found that 20 SNPs were associated with lung cancer risk with a false discovery rate threshold of lung cancer risk (odds ratio = 1.11, 95% confidence interval = 1.04-1.18) in the eight GWASs. In the eQTL analysis, we found that levels of CNOT6 mRNA expression were significantly correlated with the rs2453176 T allele, which provided additional biological basis for the observed positive association. The CNOT6 rs2453176 SNP may be a new functional susceptible locus for lung cancer risk. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  8. Polychlorinated biphenyls in honey bees

    Energy Technology Data Exchange (ETDEWEB)

    Morse, R.A.; Culliney, T.W.; Gutenmann, W.H.; Littman, C.B.; Lisk, D.J.

    1987-02-01

    Honey bees (Apis mellifera L.) may traverse a radius of several miles from their hives and contact innumerable surfaces during their collection of nectar, pollen, propolis and water. In the process, they may become contaminated with surface constituents which are indicative of the type of environmental pollution in their particular foraging area. Honey has also been analyzed as a possible indicator of heavy metal pollution. Insecticides used in the vicinity of bee hives have been found in bees and honey. It has been recently reported that appreciable concentrations of polychlorinated biphenyls (PCBs) have been found in honey bees sampled throughout Connecticut. In the work reported here, an analytical survey was conducted on PCBs in honey bees, honey, propolis and related samples in several states to learn the extent of contamination and possible sources.

  9. The non-canonical Wnt/PKC pathway regulates mitochondrial dynamics through degradation of the arm-like domain-containing protein Alex3.

    Directory of Open Access Journals (Sweden)

    Román Serrat

    Full Text Available The regulation of mitochondrial dynamics is vital in complex cell types, such as neurons, that transport and localize mitochondria in high energy-demanding cell domains. The Armcx3 gene encodes a mitochondrial-targeted protein (Alex3 that contains several arm-like domains. In a previous study we showed that Alex3 protein regulates mitochondrial aggregation and trafficking. Here we studied the contribution of Wnt proteins to the mitochondrial aggregation and dynamics regulated by Alex3. Overexpression of Alex3 in HEK293 cells caused a marked aggregation of mitochondria, which was attenuated by treatment with several Wnts. We also found that this decrease was caused by Alex3 degradation induced by Wnts. While the Wnt canonical pathway did not alter the pattern of mitochondrial aggregation induced by Alex3, we observed that the Wnt/PKC non-canonical pathway regulated both mitochondrial aggregation and Alex3 protein levels, thereby rendering a mitochondrial phenotype and distribution similar to control patterns. Our data suggest that the Wnt pathway regulates mitochondrial distribution and dynamics through Alex3 protein degradation.

  10. Phosphate Shifted Oxygen Reduction Pathway on Fe@Fe2O3Core-Shell Nanowires for Enhanced Reactive Oxygen Species Generation and Aerobic 4-Chlorophenol Degradation.

    Science.gov (United States)

    Mu, Yi; Ai, Zhihui; Zhang, Lizhi

    2017-07-18

    Phosphate ions widely exist in the environment. Previous studies revealed that the adsorption of phosphate ions on nanoscale zerovalent iron would generate a passivating oxide shell to block reactive sites and thus decrease the direct pollutant reduction reactivity of zerovalent iron. Given that molecular oxygen activation process is different from direct pollutant reduction with nanoscale zerovalent iron, it is still unclear how phosphate ions will affect molecular oxygen activation and reactive oxygen species generation with nanoscale zerovalent iron. In this study, we systematically studied the effect of phosphate ions on molecular oxygen activation with Fe@Fe 2 O 3 nanowires, a special nanoscale zerovalent iron, taking advantages of rotating ring disk electrochemical analysis. It was interesting to find that the oxygen reduction pathway on Fe@Fe 2 O 3 nanowires was gradually shifted from a four-electron reduction pathway to a sequential one-electron reduction one, along with increasing the phosphate ions concentration from 0 to 10 mmol·L -1 . This oxygen reduction pathway change greatly enhanced the molecular oxygen activation and reactive oxygen species generation performances of Fe@Fe 2 O 3 nanowires, and thus increased their aerobic 4-chlorophenol degradation rate by 10 times. These findings shed insight into the possible roles of widely existed phosphate ions in molecular oxygen activation and organic pollutants degradation with nanoscale zerovalent iron.

  11. The Non-Canonical Wnt/PKC Pathway Regulates Mitochondrial Dynamics through Degradation of the Arm-Like Domain-Containing Protein Alex3

    Science.gov (United States)

    Mirra, Serena; Quevedo, Martí; Garcia-Fernàndez, Jordi; Ulloa, Fausto; Burgaya, Ferrán; Soriano, Eduardo

    2013-01-01

    The regulation of mitochondrial dynamics is vital in complex cell types, such as neurons, that transport and localize mitochondria in high energy-demanding cell domains. The Armcx3 gene encodes a mitochondrial-targeted protein (Alex3) that contains several arm-like domains. In a previous study we showed that Alex3 protein regulates mitochondrial aggregation and trafficking. Here we studied the contribution of Wnt proteins to the mitochondrial aggregation and dynamics regulated by Alex3. Overexpression of Alex3 in HEK293 cells caused a marked aggregation of mitochondria, which was attenuated by treatment with several Wnts. We also found that this decrease was caused by Alex3 degradation induced by Wnts. While the Wnt canonical pathway did not alter the pattern of mitochondrial aggregation induced by Alex3, we observed that the Wnt/PKC non-canonical pathway regulated both mitochondrial aggregation and Alex3 protein levels, thereby rendering a mitochondrial phenotype and distribution similar to control patterns. Our data suggest that the Wnt pathway regulates mitochondrial distribution and dynamics through Alex3 protein degradation. PMID:23844091

  12. Role of the PKCα-c-Src tyrosine kinase pathway in the mediation of p120-catenin degradation in ventilator-induced lung injury.

    Science.gov (United States)

    Zhao, Tao; Zhao, Hongwei; Li, Gang; Zheng, Shengfa; Liu, Mengjie; Gu, Changping; Wang, Yuelan

    2016-11-01

    Ventilator-induced lung injury (VILI) is commonly associated with respiratory barrier dysfunction; however, the mechanisms have not been fully elucidated. This study aimed to determine the order and components of the signalling pathway that mediates the degradation of adherin junction of p120-catenin in VILI. For the in vivo study, C57BL/6 mice were pre-treated with inhibitors for 60 min prior to 4 h of mechanical ventilation. For the in vitro study, mouse lung epithelial 12 (MLE-12) cells were pre-treated with inhibitors for 60 min or small interfering RNA (siRNA) for 48 h prior to cyclic stretch at 20% for 4 h. The protein levels of protein kinase Cα (PKCα), activated c-Src and p120-catenin were determined via western blot analysis. Lung injury was determined via HE staining, immunofluorescence, wet/dry ratio and lung injury scores. High tidal volume mechanical ventilation and 20% cyclic stretch resulted in the degradation of p120-catenin. Inhibitors of PKCα blocked c-Src kinase activation and p120-catenin degradation in VILI. Inhibitors of c-Src kinase or PP2 or siRNA blocked p120-catenin degradation but not PKCα activation. The current findings demonstrates that PKCα and c-Src kinase participate in VILI. PKCα activation phosphorylates c-Src kinase and further decreases p120-catenin in VILI. © 2016 Asian Pacific Society of Respirology.

  13. Removal of 2,4-dichlorophenoxyacetic acid in aqueous solution by pulsed corona discharge treatment: Effect of different water constituents, degradation pathway and toxicity assay.

    Science.gov (United States)

    Singh, Raj Kamal; Philip, Ligy; Ramanujam, Sarathi

    2017-10-01

    A multiple pin-plane corona discharge reactor was used to generate plasma for the degradation of 2,4 dichlorophenoxyacetic acid (2,4-D) from the aqueous solution. The 2,4-D of concentration 1 mg/L was completely removed within 6 min of plasma treatment. Almost complete mineralization was achieved after the treatment time of 14 min for a 2,4-D concentration of 10 mg/L. Effects of different water constituents such as carbonates, nitrate, sulphate, chloride ions, natural organic matter (humic acids) and pH on 2,4-D degradation was studied. A significant antagonistic effect of carbonate and humic acid was observed, whereas, the effects of other ions were insignificant. A higher first order rate constant of 1.73 min -1 was observed, which was significantly decreased in the presence of carbonate ions and humic acids. Also, a higher degradation of 2,4-D was observed in acidic pH conditions. Different 2,4-D intermediates were detected and the degradation pathway of 2,4-D in plasma treatment process was suggested. The toxicity of 10 mg/L 2,4-D was completely eradicated after 10 min of plasma treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. The Azoarcus anaerobius 1,3-Dihydroxybenzene (Resorcinol) Anaerobic Degradation Pathway Is Controlled by the Coordinated Activity of Two Enhancer-Binding Proteins.

    Science.gov (United States)

    Pacheco-Sánchez, Daniel; Molina-Fuentes, Águeda; Marín, Patricia; Medina-Bellver, Javier-I; González-López, Óscar; Marqués, Silvia

    2017-05-01

    The anaerobic resorcinol degradation pathway in Azoarcus anaerobius is unique in that it uses an oxidative rather than a reductive strategy to overcome the aromatic ring stability in degradation of this compound, in a process that is dependent on nitrate respiration. We show that the pathway is organized in five transcriptional units, three of which are inducible by the presence of the substrate. Three σ 54 -dependent promoters located upstream from the three operons coding for the main pathway enzymes were identified, which shared a similar structure with conserved upstream activating sequences (UASs) located at 103 to 111 bp from the transcription start site. Expression of the pathway is controlled by the bacterial enhancer-binding proteins (bEBPs) RedR1 and RedR2, two homologous regulators that, despite their high sequence identity (97%), have nonredundant functions: RedR2, the master regulator which also controls RedR1 expression, is itself able to promote transcription from two of the promoters, while RedR1 activity is strictly dependent on the presence of RedR2. The two regulators were shown to interact with each other, suggesting that the natural mode of activation is by forming heterodimers, which become active in the presence of the substrate after its metabolization to hydroxybenzoquinone through the pathway enzymes. The model structure of the N-terminal domain of the proteins is composed of tandem GAF and PAS motifs; the possible mechanisms controlling the activity of the regulators are discussed. IMPORTANCE Azoarcus anaerobius is a strict anaerobe that is able to use 1,3-dihydroxybenzene as the sole carbon source in a process that is dependent on nitrate respiration. We have shown that expression of the pathway is controlled by two regulators of almost identical sequences: the bEBPs RedR1 and RedR2, which share 97% identity. These regulators control three promoters with similar structure. Despite their sequence identity, the two bEBPs are not redundant

  15. Distribution of the Coenzyme M Pathway of Epoxide Metabolism Among Ethene- and Vinyl Chloride-Degrading Mycobacterium Strains

    National Research Council Canada - National Science Library

    Coleman, Nicholas

    2003-01-01

    ...) and ethene assimilation pathways of Mycobacterium strain JS6O. In the present study, EaCoMT activity and genes were investigated in 10 different mycobacteria isolated on VC or ethene from diverse environmental samples...

  16. The dominant acetate degradation pathway/methanogenic composition in full-scale anaerobic digesters operating under different ammonia levels

    DEFF Research Database (Denmark)

    Fotidis, Ioannis; Karakashev, Dimitar Borisov; Angelidaki, Irini

    2014-01-01

    Ammonia is a major environmental factor influencing biomethanation in full-scale anaerobic digesters. In this study, the effect of different ammonia levels on methanogenic pathways and methanogenic community composition of full-scale biogas plants was investigated. Eight full-scale digesters...... operating under different ammonia levels were sampled, and the residual biogas production was followed in fed-batch reactors. Acetate, labelled in the methyl group, was used to determine the methanogenic pathway by following the 14CH4 and 14CO2 production. Fluorescence in situ hybridisation was used...... to determine the methanogenic communities’ composition. Results obtained clearly demonstrated that syntrophic acetate oxidation coupled with hydrogenotrophic methanogenesis was the dominant pathway in all digesters with high ammonia levels (2.8–4.57 g NH4 +-N L−1), while acetoclastic methanogenic pathway...

  17. tRNA-dependent cysteine biosynthetic pathway represents a strategy to increase cysteine contents by preventing it from thermal degradation: thermal adaptation of methanogenic archaea ancestor.

    Science.gov (United States)

    Qu, Ge; Wang, Wei; Chen, Ling-Ling; Qian, Shao-Song; Zhang, Hong-Yu

    2009-10-01

    Although cysteine (Cys) is beneficial to stabilize protein structures, it is not prevalent in thermophiles. For instance, the Cys contents in most thermophilic archaea are only around 0.7%. However, methanogenic archaea, no matter thermophilic or not, contain relatively abundant Cys, which remains elusive for a long time. Recently, Klipcan et al. correlated this intriguing property of methanogenic archaea with their unique tRNA-dependent Cys biosynthetic pathway. But, the deep reasons underlying the correlation are ambiguous. Considering the facts that free Cys is thermally labile and the tRNA-dependent Cys biosynthesis avoids the use of free Cys, we speculate that the unique Cys biosynthetic pathway represents a strategy to increase Cys contents by preventing it from thermal degradation, which may be relevant to the thermal adaptation of methanogenic archaea ancestor.

  18. Synthesized TiO{sub 2}/ZSM-5 composites used for the photocatalytic degradation of azo dye: Intermediates, reaction pathway, mechanism and bio-toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Kefu; Hu, Xin-Yan [College of the Environment and Ecology, Xiamen University, Xiamen (China); Chen, Bor-Yann; Hsueh, Chung-Chuan [Department of Chemical and Materials Engineering, National I-Lan University, I-Lan, Taiwan (China); Zhang, Qian [Department of Environmental Engineering, National Taiwan University, Taipei, Taiwan (China); Wang, Jiajie; Lin, Yu-Jung [College of the Environment and Ecology, Xiamen University, Xiamen (China); Chang, Chang-Tang, E-mail: ctchang73222@gmail.com [Department of Environmental Engineering, National I-Lan University, I-Lan, Taiwan (China)

    2016-10-15

    Highlights: • The major photo-catalytic degradation pathway of azo-dye was elaborated according to the identification of by-products from GC–MS and IC analysis. • Comparative assessment on characteristics of abiotic and biotic dye decolorization was analyzed. • EDTA (hole scavengers) and t-BuOH (radical scavengers) were used to determine the main active oxidative species in the system. • The toxicity effects of degradation intermediates of Reactive Black 5 (RB5) on the cellular respiratory activity were assessed. - Abstract: In this study, a one-step solid dispersion method was used to synthesize titanium dioxide (TiO{sub 2})/Zeolite Socony Mobil-5 (ZSM-5) composites with substantially reduced time and energy consumption. A degradation efficiency of more than 95% was achieved within 10 min using 50% PTZ (synthesized TiO{sub 2}/ZSM-5 composites with TiO{sub 2} contents of 50 wt% loaded on ZSM-5) at pH 7 and 25 °C. The possible degradation pathway of azo-dye Reactive Black 5 (RB5) was investigated using gas chromatography–mass spectrometry and ion chromatography (IC). The bonds between the N atoms and naphthalene groups are likely attacked first and cleaved by hydroxyl radicals, ultimately resulting in the decolorization and mineralization of the azo dye. A comparative assessment of the characteristics of abiotic and biotic dye decolorization was completed. In addition, the toxicity effects of the degradation intermediates of azo-dye RB5 on cellular respiratory activity were analyzed. The bio-toxicity results showed that the decay rate constants of CO{sub 2} production from the azo-dye RB5 samples at different degradation times increased initially and subsequently decreased, indicating that intermediates of higher toxicity could adhere to the catalyst surface and gradually destroyed by further photocatalytic oxidation. Additionally, EDTA (hole scavengers) and t-BuOH (radical scavengers) were used to detect the main active oxidative species in the system

  19. Metabolic analysis of the soil microbe Dechloromonas aromatica str. RCB: indications of a surprisingly complex life-style and cryptic anaerobic pathways for aromatic degradation

    Energy Technology Data Exchange (ETDEWEB)

    Salinero, Kennan Kellaris; Keller, Keith; Feil, William S.; Feil, Helene; Trong, Stephan; Di Bartolo, Genevieve; Lapidus, Alla

    2008-11-17

    Initial interest in Dechloromonas aromatica strain RCB arose from its ability to anaerobically degrade benzene. It is also able to reduce perchlorate and oxidize chlorobenzoate, toluene, and xylene, creating interest in using this organism for bioremediation. Little physiological data has been published for this microbe. It is considered to be a free-living organism. The a priori prediction that the D. aromatica genome would contain previously characterized 'central' enzymes involved in anaerobic aromatic degradation proved to be false, suggesting the presence of novel anaerobic aromatic degradation pathways in this species. These missing pathways include the benzyl succinyl synthase (bssABC) genes (responsible for formate addition to toluene) and the central benzoylCoA pathway for monoaromatics. In depth analyses using existing TIGRfam, COG, and InterPro models, and the creation of de novo HMM models, indicate a highly complex lifestyle with a large number of environmental sensors and signaling pathways, including a relatively large number of GGDEF domain signal receptors and multiple quorum sensors. A number of proteins indicate interactions with an as yet unknown host, as indicated by the presence of predicted cell host remodeling enzymes, effector enzymes, hemolysin-like proteins, adhesins, NO reductase, and both type III and type VI secretory complexes. Evidence of biofilm formation including a proposed exopolysaccharide complex with the somewhat rare exosortase (epsH), is also present. Annotation described in this paper also reveals evidence for several metabolic pathways that have yet to be observed experimentally, including a sulphur oxidation (soxFCDYZAXB) gene cluster, Calvin cycle enzymes, and nitrogen fixation (including RubisCo, ribulose-phosphate 3-epimerase, and nif gene families, respectively). Analysis of the D. aromatica genome indicates there is much to be learned regarding the metabolic capabilities, and life-style, for this microbial

  20. Metabolic analysis of the soil microbe Dechloromonas aromatica str. RCB: indications of a surprisingly complex life-style and cryptic anaerobic pathways for aromatic degradation

    Directory of Open Access Journals (Sweden)

    Feil Helene

    2009-08-01

    Full Text Available Abstract Background Initial interest in Dechloromonas aromatica strain RCB arose from its ability to anaerobically degrade benzene. It is also able to reduce perchlorate and oxidize chlorobenzoate, toluene, and xylene, creating interest in using this organism for bioremediation. Little physiological data has been published for this microbe. It is considered to be a free-living organism. Results The a priori prediction that the D. aromatica genome would contain previously characterized "central" enzymes to support anaerobic aromatic degradation of benzene proved to be false, suggesting the presence of novel anaerobic aromatic degradation pathways in this species. These missing pathways include the benzylsuccinate synthase (bssABC genes (responsible for fumarate addition to toluene and the central benzoyl-CoA pathway for monoaromatics. In depth analyses using existing TIGRfam, COG, and InterPro models, and the creation of de novo HMM models, indicate a highly complex lifestyle with a large number of environmental sensors and signaling pathways, including a relatively large number of GGDEF domain signal receptors and multiple quorum sensors. A number of proteins indicate interactions with an as yet unknown host, as indicated by the presence of predicted cell host remodeling enzymes, effector enzymes, hemolysin-like proteins, adhesins, NO reductase, and both type III and type VI secretory complexes. Evidence of biofilm formation including a proposed exopolysaccharide complex and exosortase (epsH are also present. Annotation described in this paper also reveals evidence for several metabolic pathways that have yet to be observed experimentally, including a sulphur oxidation (soxFCDYZAXB gene cluster, Calvin cycle enzymes, and proteins involved in nitrogen fixation in other species (including RubisCo, ribulose-phosphate 3-epimerase, and nif gene families, respectively. Conclusion Analysis of the D. aromatica genome indicates there is much to be

  1. Photocatalysis of bisphenol A by an easy-settling titania/titanate composite: Effects of water chemistry factors, degradation pathway and theoretical calculation.

    Science.gov (United States)

    Zhao, Xiao; Du, Penghui; Cai, Zhengqing; Wang, Ting; Fu, Jie; Liu, Wen

    2018-01-01

    Bisphenol A (BPA) is a widely concerned endocrine disrupting chemical and hard to be removed through conventional wastewater treatment processes. In this study, we developed a TiO 2 decorated titanate nanotubes composite (TiO 2 /TNTs) and used for photocatalytic degradation of BPA. TEM and XRD analysis show that the TiO 2 /TNTs is a nano-composite of anatase and titanate, with anatase acting as the primary photocatalytic site and titanate as the skeleton. TiO 2 /TNTs exhibited excellent photocatalytic reactivity and its easy-settling property leaded to good reusability. After 5 reuse cycles, TiO 2 /TNTs also could photo-degrade 91.2% of BPA with a high rate constant (k 1 ) of 0.039 min -1 , which was much better than TiO 2 and TNTs. Higher pH facilitated photocatalysis due to more reactive oxygen species produced and less material aggregation. The presence of NaCl and CaCl 2 showed negligible effects on BPA degradation, but NaHCO 3 caused an inhibition effect resulting from consumption of ·OH. Humic acid inhibited degradation mainly due to blockage of the active sites of TiO 2 /TNTs. Degradation pathway was well interpreted through theoretical calculation. Hydroxyl radical played the dominate role in BPA photodegradation, and the atoms of BPA with high Fukui index based on density-functional theory (DFT) calculation are the radical easy-attacking (f 0 ) sites. Considering the good photocatalytic reactivity, reusability, stability and settle property, TiO 2 /TNTs promises to be an efficient alternative for removal of organic compounds from wastewaters. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Amyloid-beta (Aβ₁₋₄₂)-induced paralysis in Caenorhabditis elegans is inhibited by the polyphenol quercetin through activation of protein degradation pathways.

    Science.gov (United States)

    Regitz, Charlotte; Dußling, Lisa Marie; Wenzel, Uwe

    2014-10-01

    Dietary polyphenols are suggested to play a role in the prevention of Alzheimer's disease, of which accumulation of aggregated beta amyloid (Aβ) is a key histopathological hallmark. We used the transgenic Caenorhabditis elegans strain CL2006, which expresses human Aβ₁₋₄₂ under control of a muscle-specific promoter and responds to Aβ₁₋₄₂ aggregation with paralysis, to test effects of the polyphenol quercetin on the phenotype. Quercetin dose-dependently decreased the amount of aggregated proteins in solution and also paralysis in CL2006. The knockdown of key components of unfolded protein response in mitochondria or the endoplasmic reticulum by RNA-interference (RNAi) enhanced paralysis in CL2006 but did not prevent the paralysis reducing activities of quercetin. RNAi for essential members of proteasomal protein degradation or macroautophagy also significantly increased paralysis but prevented quercetin from being effective. Quercetin increased proteasomal activity and, moreover, enhanced the flow of proteins through the macroautophagy pathway as reflected by reduced lysosome staining. The proteostasis network, including unfolded protein response, defines the aggregation of Aβ₁₋₄₂ and the associated paralysis phenotype in a nematode model for Alzheimer's disease. The polyphenol quercetin, by specifically activating macroautophagy and proteasomal degradation pathways, proved able to prevent Aβ₁₋₄₂ agregation and paralysis. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. A Functional 4-Hydroxysalicylate/Hydroxyquinol Degradative Pathway Gene Cluster Is Linked to the Initial Dibenzo-p-Dioxin Pathway Genes in Sphingomonas sp. Strain RW1

    OpenAIRE

    Armengaud, Jean; Timmis, Kenneth N.; Wittich, Rolf-Michael

    1999-01-01

    The bacterium Sphingomonas sp. strain RW1 is able to use dibenzo-p-dioxin, dibenzofuran, and several hydroxylated derivatives as sole sources of carbon and energy. We have determined and analyzed the nucleic acid sequence of a 9,997-bp HindIII fragment downstream of cistrons dxnA1A2, which encode the dioxygenase component of the initial dioxygenase system of the corresponding catabolic pathways. This fragment contains 10 colinear open reading frames (ORFs), apparently organized in one compact...

  4. Catalytic degradation of recalcitrant pollutants by Fenton-like process using polyacrylonitrile-supported iron (II) phthalocyanine nanofibers: Intermediates and pathway.

    Science.gov (United States)

    Zhu, Zhexin; Chen, Yi; Gu, Yan; Wu, Fei; Lu, Wangyang; Xu, Tiefeng; Chen, Wenxing

    2016-04-15

    Iron (II) phthalocyanine (FePc) molecules were isolated in polyacrylonitrile (PAN) nanofibers by electrospinning to prevent the formation of dimers and oligomers. Carbamazepine (CBZ) and Rhodamine B (RhB) degradation was investigated during a Fenton-like process with FePc/PAN nanofibers. Classical quenching tests with isopropanol and electron paramagnetic resonance tests with 5,5-dimethyl-pyrroline-oxide as spin-trapping agent were performed to determine the formation of active species during hydrogen peroxide (H2O2) decomposition by FePc/PAN nanofibers. After eight recycles for CBZ degradation over the FePc/PAN nanofibers/H2O2 system, the removal ratios of CBZ remained at 99%. Seven by-products of RhB and twelve intermediates of CBZ were identified using ultra-performance liquid chromatography and high-resolution mass spectrometry. Pathways of CBZ and RhB degradation were proposed based on the identified intermediates. As the reaction proceeded, all CBZ and RhB aromatic nucleus intermediates decreased and were transformed to small acids, but also to potentially toxic epoxide-containing intermediates and acridine, because of the powerful oxidation ability of •OH in the catalytic system. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. HIV-1 Promotes the Degradation of Components of the Type 1 IFN JAK/STAT Pathway and Blocks Anti-viral ISG Induction.

    Science.gov (United States)

    Gargan, Siobhan; Ahmed, Suaad; Mahony, Rebecca; Bannan, Ciaran; Napoletano, Silvia; O'Farrelly, Cliona; Borrow, Persephone; Bergin, Colm; Stevenson, Nigel J

    2018-04-01

    Anti-retroviral therapy successfully suppresses HIV-1 infection, but fails to provide a cure. During infection Type 1 IFNs normally play an essential role in viral clearance, but in vivo IFN-α only has a modest impact on HIV-1 infection, suggesting its possible targeting by HIV. Here, we report that the HIV protein, Vif, inhibits effective IFN-α signalling via degradation of essential JAK/STAT pathway components. We found that STAT1 and STAT3 are specifically reduced in HEK293T cells expressing Vif and that full length, infectious HIV-1 IIIB strain promotes their degradation in a Vif-dependent manner. HIV-1 IIIB infection of myeloid ThP-1 cells also reduced the IFN-α-mediated induction of the anti-viral gene, ISG15, but not MxA, revealing a functional consequence of this HIV-1-mediated immune evasion strategy. Interestingly, while total STAT levels were not reduced upon in vitro IIIB infection of primary human PBMCs, IFN-α-mediated phosphorylation of STAT1 and STAT3 and ISG induction were starkly reduced, with removal of Vif (IIIBΔVif), partially restoring pSTATs, ISG15 and MxB induction. Similarly, pSTAT1 and pSTAT3 expression and IFN-α-induced ISG15 were reduced in PBMCs from HIV-infected patients, compared to healthy controls. Furthermore, IFN-α pre-treatment of a CEM T lymphoblast cells significantly inhibited HIV infection/replication (measured by cellular p24), only in the absence of Vif (IIIBΔVif), but was unable to suppress full length IIIB infection. When analysing the mechanism by which Vif might target the JAK/STAT pathway, we found Vif interacts with both STAT1 and STAT3, (but not STAT2), and its expression promotes ubiquitination and MG132-sensitive, proteosomal degradation of both proteins. Vif's Elongin-Cullin-SOCS-box binding motif enables the formation of an active E3 ligase complex, which we found to be required for Vif's degradation of STAT1 and STAT3. In fact, the E3 ligase scaffold proteins, Cul5 and Rbx2, were also found to be

  6. The genes of the sulphoquinovose catabolism in Escherichia coli are also associated with a previously unknown pathway of lactose degradation.

    Science.gov (United States)

    Kaznadzey, Anna; Shelyakin, Pavel; Belousova, Evgeniya; Eremina, Aleksandra; Shvyreva, Uliana; Bykova, Darya; Emelianenko, Vera; Korosteleva, Anastasiya; Tutukina, Maria; Gelfand, Mikhail S

    2018-02-16

    Comparative genomics analysis of conserved gene cassettes demonstrated resemblance between a recently described cassette of genes involved in sulphoquinovose degradation in Escherichia coli K-12 MG1655 and a Bacilli cassette linked with lactose degradation. Six genes from both cassettes had similar functions related to carbohydrate metabolism, namely, hydrolase, aldolase, kinase, isomerase, transporter, and transcription factor. The Escherichia coli sulphoglycolysis cassette was thus predicted to be associated with lactose degradation. This prediction was confirmed experimentally: expression of genes coding for aldolase (yihT), isomerase (yihS), and kinase (yihV) was dramatically increased during growth on lactose. These genes were previously shown to be activated during growth on sulphoquinovose, so our observation may indicate multi-functional capabilities of the respective proteins. Transcription starts for yihT, yihV and yihW were mapped in silico, in vitro and in vivo. Out of three promoters for yihT, one was active only during growth on lactose. We further showed that switches in yihT transcription are controlled by YihW, a DeoR-family transcription factor in the Escherichia coli cassette. YihW acted as a carbon source-dependent dual regulator involved in sustaining the baseline growth in the absence of lac-operon, with function either complementary, or opposite to a global regulator of carbohydrate metabolism, cAMP-CRP.

  7. Arctigenin promotes degradation of inducible nitric oxide synthase through CHIP-associated proteasome pathway and suppresses its enzyme activity.

    Science.gov (United States)

    Yao, Xiangyang; Li, Guilan; Lü, Chaotian; Xu, Hui; Yin, Zhimin

    2012-10-01

    Arctigenin, a natural dibenzylbutyrolactone lignan compound, has been reported to possess anti-inflammatory properties. Previous works showed that arctigenin decreased lipopolysaccharide (LPS)-induced iNOS at transcription level. However, whether arctigenin could regulate iNOS at the post-translational level is still unclear. In the present study, we demonstrated that arctigenin promoted the degradation of iNOS which is expressed under LPS stimulation in murine macrophage-like RAW 264.7 cells. Such degradation of iNOS protein is due to CHIP-associated ubiquitination and proteasome-dependency. Furthermore, arctigenin decreased iNOS phosphorylation through inhibiting ERK and Src activation, subsequently suppressed iNOS enzyme activity. In conclusion, our research displays a new finding that arctigenin can promote the ubiqitination and degradation of iNOS after LPS stimulation. iNOS activity regulated by arctigenin is likely to involve a multitude of crosstalking mechanisms. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. HUWE1 interacts with BRCA1 and promotes its degradation in the ubiquitin–proteasome pathway (Biochemical and Biophysical Research Communications, v. 444 issue 3)

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaozhen [Department of Cell Biology, Peking University Health Science Center, Beijing 100191 (China); Institute of Systems Biology, Peking University, Beijing 100191 (China); Lu, Guang; Li, Li; Yi, Juan; Yan, Kaowen; Wang, Yaqing; Zhu, Baili; Kuang, Jingyu; Lin, Ming; Zhang, Sha [Department of Cell Biology, Peking University Health Science Center, Beijing 100191 (China); Shao, Genze, E-mail: gzshao@bjmu.edu.cn [Department of Cell Biology, Peking University Health Science Center, Beijing 100191 (China); Institute of Systems Biology, Peking University, Beijing 100191 (China)

    2014-02-14

    Highlights: • The 2000–2634 aa region of HUWE1 mediates the interaction with BRCA1 degron. • HUWE1 promotes the degradation of BRCA1 through the ubiquitin–proteasome pathway. • HUWE1 expression is inversely correlated with BRCA1 in breast cancer cells. • RNAi inhibition of HUWE1 confers increased resistance of MCF-10F cells to IR and MMC. - Abstract: The cellular BRCA1 protein level is essential for its tumor suppression activity and is tightly regulated through multiple mechanisms including ubiquitn–proteasome system. E3 ligases are involved to promote BRCA1 for ubiquitination and degradation. Here, we identified HUWE1/Mule/ARF-BP1 as a novel BRCA1-interacting protein involved in the control of BRCA1 protein level. HUWE1binds BRCA1 through its N-terminus degron domain. Depletion of HUWE1 by siRNA-mediated interference significantly increases BRCA1 protein levels and prolongs the half-life of BRCA1. Moreover, exogenous expression of HUWE1 promotes BRCA1 degradation through the ubiquitin–proteasome pathway, which could explain an inverse correlation between HUWE1 and BRCA1 levels in MCF10F, MCF7 and MDA-MB-231 breast cancer cells. Consistent with a functional role for HUWE1 in regulating BRCA1-mediated cellular response to DNA damage, depletion of HUWE1 by siRNA confers increased resistance to ionizing radiation and mitomycin. These data indicate that HUWE1 is a critical negative regulator of BRCA1 and suggest a new molecular mechanism for breast cancer pathogenesis.

  9. HUWE1 interacts with BRCA1 and promotes its degradation in the ubiquitin–proteasome pathway (Biochemical and Biophysical Research Communications, v. 444, isse 4)

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaozhen [Department of Cell Biology, Peking University Health Science Center, Beijing 100191 (China); Institute of Systems Biology, Peking University, Beijing 100191 (China); Lu, Guang; Li, Li; Yi, Juan; Yan, Kaowen; Wang, Yaqing; Zhu, Baili; Kuang, Jingyu; Lin, Ming; Zhang, Sha [Department of Cell Biology, Peking University Health Science Center, Beijing 100191 (China); Shao, Genze, E-mail: gzshao@bjmu.edu.cn [Department of Cell Biology, Peking University Health Science Center, Beijing 100191 (China); Institute of Systems Biology, Peking University, Beijing 100191 (China)

    2014-02-21

    Highlights: • The 2000–2634aa region of HUWE1 mediates the interaction with BRCA1 degron. • HUWE1 promotes the degradation of BRCA1 through the ubiquitin–proteasome pathway. • HUWE1 expression is inversely correlated with BRCA1 in breast cancer cells. • RNAi inhibition of HUWE1 confers increased resistance of MCF-10F cells to IR and MMC. - Abstract: The cellular BRCA1 protein level is essential for its tumor suppression activity and is tightly regulated through multiple mechanisms including ubiquitn–proteasome system. E3 ligases are involved to promote BRCA1 for ubiquitination and degradation. Here, we identified HUWE1/Mule/ARF-BP1 as a novel BRCA1-interacting protein involved in the control of BRCA1 protein level. HUWE1 binds BRCA1 through its N-terminus degron domain. Depletion of HUWE1 by siRNA-mediated interference significantly increases BRCA1 protein levels and prolongs the half-life of BRCA1. Moreover, exogenous expression of HUWE1 promotes BRCA1 degradation through the ubiquitin–proteasome pathway, which could explain an inverse correlation between HUWE1 and BRCA1 levels in MCF10F, MCF7 and MDA-MB-231 breast cancer cells. Consistent with a functional role for HUWE1 in regulating BRCA1-mediated cellular response to DNA damage, depletion of HUWE1 by siRNA confers increased resistance to ionizing radiation and mitomycin. These data indicate that HUWE1 is a critical negative regulator of BRCA1 and suggest a new molecular mechanism for breast cancer pathogenesis.

  10. Involvement of Bcl-xL degradation and mitochondrial-mediated apoptotic pathway in pyrrolizidine alkaloids-induced apoptosis in hepatocytes

    International Nuclear Information System (INIS)

    Ji Lili; Chen Ying; Liu Tianyu; Wang Zhengtao

    2008-01-01

    Pyrrolizidine alkaloids (PAs) are natural hepatotoxins with worldwide distribution in more than 6000 high plants including medicinal herbs or teas. The aim of this study is to investigate the signal pathway involved in PAs-induced hepatotoxicity. Our results showed that clivorine, isolated from Ligularia hodgsonii Hook, decreased cell viability and induced apoptosis in L-02 cells and mouse hepatocytes. Western-blot results showed that clivorine induced caspase-3/-9 activation, mitochondrial release of cytochrome c and decreased anti-apoptotic Bcl-xL in a time (8-48 h)- and concentration (1-100 μM)-dependent manner. Furthermore, inhibitors of pan-caspase, caspase-3 and caspase-9 significantly inhibited clivorine-induced apoptosis and rescued clivorine-decreased cell viability. Polyubiquitination of Bcl-xL was detected after incubation with 100 μM clivorine for 40 h in the presence of proteasome specific inhibitor MG132, indicating possible degradation of Bcl-xL protein. Furthermore, pretreatment with MG132 or calpain inhibitor I for 2 h significantly enhanced clivorine-decreased Bcl-xL level and cell viability. All the other tested PAs such as senecionine, isoline and monocrotaline decreased mouse hepatocytes viability in a concentration-dependent manner. Clivorine (10 μM) induced caspase-3 activation and decreased Bcl-xL was also confirmed in mouse hepatocytes. Meanwhile, another PA senecionine isolated from Senecio vulgaris L also induced apoptosis, caspase-3 activation and decreased Bcl-xL in mouse hepatocytes. In conclusion, our results suggest that PAs may share the same hepatotoxic signal pathway, which involves degradation of Bcl-xL protein and thus leading to the activation of mitochondrial-mediated apoptotic pathway

  11. Murrayafoline A attenuates the Wnt/{beta}-catenin pathway by promoting the degradation of intracellular {beta}-catenin proteins

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hyuk; Gwak, Jungsug; Cho, Munju; Ryu, Min-Jung [PharmacoGenomics Research Center, Inje University, Busan 614-735 (Korea, Republic of); Lee, Jee-Hyun; Kim, Sang Kyum; Kim, Young Ho [College of Pharmacy, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Lee, Gye Won [Department of Pharmaceutical Engineering, Konyang University, Nonsan 320-711 (Korea, Republic of); Yun, Mi-Young [Department of Beauty Health Care, Daejeon University, Daejeon 305-764 (Korea, Republic of); Cuong, Nguyen Manh [Institute of Natural Products Chemistry, Vietnam Academy of Science and Technology, Hanoi (Viet Nam); Shin, Jae-Gook [PharmacoGenomics Research Center, Inje University, Busan 614-735 (Korea, Republic of); Song, Gyu-Yong, E-mail: gysong@cnu.ac.kr [College of Pharmacy, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Oh, Sangtaek, E-mail: ohsa@inje.ac.kr [PharmacoGenomics Research Center, Inje University, Busan 614-735 (Korea, Republic of)

    2010-01-01

    Molecular lesions in Wnt/{beta}-catenin signaling and subsequent up-regulation of {beta}-catenin response transcription (CRT) occur frequently during the development of colon cancer. To identify small molecules that suppress CRT, we screened natural compounds in a cell-based assay for detection of TOPFalsh reporter activity. Murrayafoline A, a carbazole alkaloid isolated from Glycosmis stenocarpa, antagonized CRT that was stimulated by Wnt3a-conditioned medium (Wnt3a-CM) or LiCl, an inhibitor of glycogen synthase kinase-3{beta} (GSK-3{beta}), and promoted the degradation of intracellular {beta}-catenin without altering its N-terminal phosphorylation at the Ser33/37 residues, marking it for proteasomal degradation, or the expression of Siah-1, an E3 ubiquitin ligase. Murrayafoline A repressed the expression of cyclin D1 and c-myc, which is known {beta}-catenin/T cell factor (TCF)-dependent genes and thus inhibited the proliferation of various colon cancer cells. These findings indicate that murrayafoline A may be a potential chemotherapeutic agent for use in the treatment of colon cancer.

  12. Murrayafoline A attenuates the Wnt/β-catenin pathway by promoting the degradation of intracellular β-catenin proteins

    International Nuclear Information System (INIS)

    Choi, Hyuk; Gwak, Jungsug; Cho, Munju; Ryu, Min-Jung; Lee, Jee-Hyun; Kim, Sang Kyum; Kim, Young Ho; Lee, Gye Won; Yun, Mi-Young; Cuong, Nguyen Manh; Shin, Jae-Gook; Song, Gyu-Yong; Oh, Sangtaek

    2010-01-01

    Molecular lesions in Wnt/β-catenin signaling and subsequent up-regulation of β-catenin response transcription (CRT) occur frequently during the development of colon cancer. To identify small molecules that suppress CRT, we screened natural compounds in a cell-based assay for detection of TOPFalsh reporter activity. Murrayafoline A, a carbazole alkaloid isolated from Glycosmis stenocarpa, antagonized CRT that was stimulated by Wnt3a-conditioned medium (Wnt3a-CM) or LiCl, an inhibitor of glycogen synthase kinase-3β (GSK-3β), and promoted the degradation of intracellular β-catenin without altering its N-terminal phosphorylation at the Ser33/37 residues, marking it for proteasomal degradation, or the expression of Siah-1, an E3 ubiquitin ligase. Murrayafoline A repressed the expression of cyclin D1 and c-myc, which is known β-catenin/T cell factor (TCF)-dependent genes and thus inhibited the proliferation of various colon cancer cells. These findings indicate that murrayafoline A may be a potential chemotherapeutic agent for use in the treatment of colon cancer.

  13. GPG-NH2 acts via the metabolite αHGA to target HIV-1 Env to the ER-associated protein degradation pathway

    Directory of Open Access Journals (Sweden)

    Vahlne Anders

    2010-03-01

    Full Text Available Abstract Background The synthetic peptide glycyl-prolyl-glycine amide (GPG-NH2 was previously shown to abolish the ability of HIV-1 particles to fuse with the target cells, by reducing the content of the viral envelope glycoprotein (Env in progeny HIV-1 particles. The loss of Env was found to result from GPG-NH2 targeting the Env precursor protein gp160 to the ER-associated protein degradation (ERAD pathway during its maturation. However, the anti-viral effect of GPG-NH2 has been shown to be mediated by its metabolite α-hydroxy-glycineamide (αHGA, which is produced in the presence of fetal bovine serum, but not human serum. In accordance, we wanted to investigate whether the targeting of gp160 to the ERAD pathway by GPG-NH2 was attributed to its metabolite αHGA. Results In the presence of fetal bovine serum, GPG-NH2, its intermediary metabolite glycine amide (G-NH2, and final metabolite αHGA all induced the degradation of gp160 through the ERAD pathway. However, when fetal bovine serum was replaced with human serum only αHGA showed an effect on gp160, and this activity was further shown to be completely independent of serum. This indicated that GPG-NH2 acts as a pro-drug, which was supported by the observation that it had to be added earlier to the cell cultures than αHGA to induce the degradation of gp160. Furthermore, the substantial reduction of Env incorporation into HIV-1 particles that occurs during GPG-NH2 treatment was also achieved by treating HIV-1 infected cells with αHGA. Conclusions The previously observed specificity of GPG-NH2 towards gp160 in HIV-1 infected cells, resulting in the production of Env (gp120/gp41 deficient fusion incompetent HIV-1 particles, was most probably due to the action of the GPG-NH2 metabolite αHGA.

  14. Carbazole-degradative IncP-7 plasmid pCAR1.2 is structurally unstable in Pseudomonas fluorescens Pf0-1, which accumulates catechol, the intermediate of the carbazole degradation pathway.

    Science.gov (United States)

    Takahashi, Yurika; Shintani, Masaki; Li, Li; Yamane, Hisakazu; Nojiri, Hideaki

    2009-06-01

    We determined the effect of the host on the function and structure of the nearly identical IncP-7 carbazole-degradative plasmids pCAR1.1 and pCAR1.2. We constructed Pseudomonas aeruginosa PAO1(pCAR1.2) and P. fluorescens Pf0-1Km(pCAR1.2) and compared their growth on carbazole- and succinate-containing media with that of P. putida KT2440(pCAR1.1). We also assessed the stability of the genetic structures of the plasmids in each of the three hosts. Pf0-1Km(pCAR1.2) showed dramatically delayed growth when carbazole was supplied as the sole carbon source, while the three strains grew at nearly the same rate on succinate. Among the carbazole-grown Pf0-1Km(pCAR1.2) cells, two types of deficient strains appeared and dominated the population; such dominance was not observed in the other two strains or for succinate-grown Pf0-1Km(pCAR1.2). Genetic analysis showed that the two deficient strains possessed pCAR1.2 derivatives in which the carbazole-degradative car operon was deleted or its regulatory gene, antR, was deleted by homologous recombination between insertion sequences. From genomic information and quantitative reverse transcription-PCR analyses of the genes involved in carbazole mineralization by Pf0-1Km(pCAR1.2), we found that the cat genes on the chromosome of Pf0-1Km, which are necessary for the degradation of catechol (a toxic intermediate in the carbazole catabolic pathway), were not induced in the presence of carbazole. The resulting accumulation of catechol may have enabled the strain that lost its carbazole-degrading ability to have overall higher fitness than the wild-type strain. These results suggest that the functions of the chromosomal genes contributed to the selection of plasmid derivatives with altered structures.

  15. Degradation of di(2-ethyl hexyl) phthalate by Fusarium culmorum: Kinetics, enzymatic activities and biodegradation pathway based on quantum chemical modelingpathway based on quantum chemical modeling

    Energy Technology Data Exchange (ETDEWEB)

    Ahuactzin-Pérez, Miriam [Doctorado en Biología Experimental, Universidad Autónoma Metropolitana-Iztapalapa (UAM-I) (Mexico); Facultad de Agrobiología, Universidad Autónoma de Tlaxcala, Ixtacuixtla, Tlaxcala (Mexico); Tlecuitl-Beristain, Saúl; García-Dávila, Jorge [Universidad Politécnica de Tlaxcala, San Pedro Xalcatzinco, Tepeyanco, Tlaxcala CP 90180 (Mexico); González-Pérez, Manuel [Universidad Popular Autónoma del Estado de Puebla, Puebla CP 72410 (Mexico); Gutiérrez-Ruíz, María Concepción [Departamento de Ciencias de la Salud, Universidad Autónoma Metropolitana-Iztapalapa, D.F (Mexico); Sánchez, Carmen, E-mail: sanher6@hotmail.com [Laboratory of Biotechnology, Research Centre for Biological Sciences, Universidad Autónoma de Tlaxcala, Ixtacuixtla, Tlaxcala CP. 90062 (Mexico)

    2016-10-01

    Di(2-ethylhexyl) phthalate (DEHP) is a plasticizer widely used in the manufacture of plastics, and it is an environmental contaminant. The specific growth rate (μ), maximum biomass (X{sub max}), biodegradation constant of DEHP (k), half-life (t{sub 1/2}) of DEHP biodegradation and removal efficiency of DEHP, esterase and laccase specific activities, and enzymatic yield parameters were evaluated for Fusarium culmorum grown on media containing glucose and different concentrations of DEHP (0, 500 and 1000 mg/L). The greatest μ and the largest X{sub max} occurred in media supplemented with 1000 mg of DEHP/L. F. culmorum degraded 95% of the highest amount of DEHP tested (1000 mg/L) within 60 h of growth. The k and t{sub 1/2} were 0.024 h{sup −1} and 28 h, respectively, for both DEHP concentrations. The removal efficiency of DEHP was 99.8% and 99.9% for 1000 and 500 mg/L, respectively. Much higher specific esterase activity than specific laccase activity was observed in all media tested. The compounds of biodegradation of DEHP were identified by GC–MS. A DEHP biodegradation pathway by F. culmorum was proposed on the basis of the intermolecular flow of electrons of the identified intermediate compounds using quantum chemical modeling. DEHP was fully metabolized by F. culmorum with butanediol as the final product. This fungus offers great potential in bioremediation of environments polluted with DEHP. - Highlights: • F. culmorum degraded 95% of DEHP (1000 mg/L) within 60 h. • Removal efficiency of DEHP was 99.8% and 99.9% for 1000 and 500 mg/L, respectively. • DEHP was fully metabolized by F. culmorum, with butanediol as the final product. • A DEHP biodegradation pathway was proposed using on quantum chemical modeling.

  16. Heterogeneous photo-Fenton decolorization of Orange II over Al-pillared Fe-smectite: Response surface approach, degradation pathway, and toxicity evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Huiyuan; Li, Yanli [Department of Environmental Engineering, Wuhan University, Wuhan 430079 (China); Xiang, Luojing [Department of Environmental Engineering, Wuhan University, Wuhan 430079 (China); Université de Poitiers, UMR CNRS 7285, IC2MP, ENSIP, B1, 1 rue Marcel Doré, TSA 41105, Poitiers 86073 Cedex 9 (France); Huang, Qianqian; Qiu, Juanjuan [Department of Environmental Engineering, Wuhan University, Wuhan 430079 (China); Zhang, Hui, E-mail: eeng@whu.edu.cn [Department of Environmental Engineering, Wuhan University, Wuhan 430079 (China); Sivaiah, Matte Venkata; Baron, Fabien; Barrault, Joel; Petit, Sabine [Université de Poitiers, UMR CNRS 7285, IC2MP, ENSIP, B1, 1 rue Marcel Doré, TSA 41105, Poitiers 86073 Cedex 9 (France); Valange, Sabine, E-mail: sabine.valange@univ-poitiers.fr [Université de Poitiers, UMR CNRS 7285, IC2MP, ENSIP, B1, 1 rue Marcel Doré, TSA 41105, Poitiers 86073 Cedex 9 (France)

    2015-04-28

    Highlights: • Al-pillared Fe-smectite was synthesized and used as the photo-Fenton catalyst. • Response surface methodology was used to study the effects of reaction parameters. • The main intermediate products were identified by GC–MS technique. • A possible degradation pathway of Orange II was proposed. • All the generated products of Orange II were less toxic than the original dye. - Abstract: A ferric smectite clay material was synthesized and further intercalated with Al{sub 2}O{sub 3} pillars for the first time with the aim of evaluating its ability to be used as heterogeneous catalyst for the photo-Fenton decolorization of azo dye Orange II. UV irradiation was found to enhance the activity of the catalyst in the heterogeneous photo-Fenton process. Catalyst loading of 0.5 g/L and hydrogen peroxide concentration of 13.5 mM yielded a remarkable color removal, accompanied by excellent catalyst stability. The decolorization of Orange II followed the pseudo-first-order kinetics for initial dye concentrations from 20 to 160 mg/L. The central composite design (CCD) based on the response surface methodology (RSM) was applied to evaluate the effects of several operating parameters, namely initial pH, catalyst loading and hydrogen peroxide concentration, on the decolorization efficiency. The RSM model was derived and the response surface plots were developed based on the results. Moreover, the main intermediate products were separated and identified using gas chromatography–mass spectrometry (GC–MS) and a possible degradation pathway was proposed accordingly. The acute toxicity experiments illustrated that the Daphniamagna immobilization rate continuously decreased during 150 min reaction, indicating that the effluent was suitable for sequential biological treatment.

  17. Electroacupuncture inhibits apoptosis in annulus fibrosis cells through suppression of the mitochondria-dependent pathway in a rat model of cervical intervertebral disc degradation

    Directory of Open Access Journals (Sweden)

    Jun Liao

    2012-01-01

    Full Text Available The purpose of this study was to investigate whether treatment with electroacupuncture (EA inhibited mitochondria-dependent apoptosis in annulus fibrosis (AF cells in a rat model of cervical intervertebral disc degradation induced by unbalanced dynamic and static forces. Forty Sprague-Dawley rats were used in this study, of which 30 underwent surgery to induce cervical intervertebral disc degradation, 10 rats received EA at acupoints Dazhui (DU 14 and Shousanli (LI 10. TUNEL staining was measured to assess apoptosis in AF cells, immunohistochemistry was used to examine Bcl-2 and Bax expression, colorimetric assays were used to determine caspase 9 and caspase 3 activities and RT-PCR and western blotting were used to assess the mRNA and protein expression of Crk and ERK2. Treatment with EA reduced the number of AF-positive cells in TUNEL staining, increased Bcl-2-positive cells and decreased Bax-positive cells in immunohistochemical staining, significantly inhibited the activation of caspases-9 and -3, and enhanced the mRNA and protein expression of Crk and ERK2. Our data show that EA inhibits AF cell apoptosis via the mitochondria-dependent pathway and up-regulates Crk and ERK2 expression. These results suggest that treatment with may be a good alternative therapy for preventing cervical spondylosis.

  18. Decolorization of azo dye C.I. Reactive Black 5 by ozonation in aqueous solution: influencing factors, degradation products, reaction pathway and toxicity assessment.

    Science.gov (United States)

    Zheng, Qing; Dai, Yong; Han, Xiangyun

    2016-01-01

    In this study, ozonation treatment of C.I. Reactive Black 5 (RB5) was investigated at various operating parameters. The results showed that the aqueous solution initially containing 200 mg/L RB5 was quickly decolorized at pH 8.0 with an ozone dose of 3.2 g/h. Reaction intermediates with m/z 281, 546, 201, 350, 286 and 222 were elucidated using liquid chromatography-mass spectrometry, while sulfate ion, nitrate ion and three carboxylic acids (i.e., oxalic acid, formic acid, and acetic acid) were identified by ion exchange chromatography. Thus, the cleavage of the azo bond and the introduction of OH groups in the corresponding positions were proposed as the predominant reaction pathway. The detachment of sulfonic groups was also commonly observed during the ozonation treatment. The proposed degradation mechanism was confirmed by frontier electron density calculations, suggesting the feasibility of predicting the major events in the whole ozonation process with the computational method. Compared with RB5 degradation, the reduction of total organic carbon (TOC) proceeded much more slowly, and approximately 54% TOC was removed after 4 h of ozonation. Acute toxicity tests with Photobacterium phosphoreum showed that the toxicity of reaction solution was firstly increased and then decreased to a negligible level after 160 min.

  19. Gene mdpC plays a regulatory role in the methyl-tert-butyl ether degradation pathway of Methylibium petroleiphilum strain PM1.

    Science.gov (United States)

    Joshi, Geetika; Schmidt, Radomir; Scow, Kate M; Denison, Michael S; Hristova, Krassimira R

    2015-04-01

    Among the few bacteria known to utilize methyl tert-butyl ether (MTBE) as a sole carbon source, Methylibium petroleiphilum PM1 is a well-characterized organism with a sequenced genome; however, knowledge of the genetic regulation of its MTBE degradation pathway is limited. We investigated the role of a putative transcriptional activator gene, mdpC, in the induction of MTBE-degradation genes mdpA (encoding MTBE monooxygenase) and mdpJ (encoding tert-butyl alcohol hydroxylase) of strain PM1 in a gene-knockout mutant mdpC(-). We also utilized quantitative reverse transcriptase PCR assays targeting genes mdpA, mdpJ and mdpC to determine the effects of the mutation on transcription of these genes. Our results indicate that gene mdpC is involved in the induction of both mdpA and mdpJ in response to MTBE and tert-butyl alcohol (TBA) exposure in PM1. An additional independent mechanism may be involved in the induction of mdpJ in the presence of TBA. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  20. Specific Hsp100 Chaperones Determine the Fate of the First Enzyme of the Plastidial Isoprenoid Pathway for Either Refolding or Degradation by the Stromal Clp Protease in Arabidopsis.

    Science.gov (United States)

    Pulido, Pablo; Llamas, Ernesto; Llorente, Briardo; Ventura, Salvador; Wright, Louwrance P; Rodríguez-Concepción, Manuel

    2016-01-01

    The lifespan and activity of proteins depend on protein quality control systems formed by chaperones and proteases that ensure correct protein folding and prevent the formation of toxic aggregates. We previously found that the Arabidopsis thaliana J-protein J20 delivers inactive (misfolded) forms of the plastidial enzyme deoxyxylulose 5-phosphate synthase (DXS) to the Hsp70 chaperone for either proper folding or degradation. Here we show that the fate of Hsp70-bound DXS depends on pathways involving specific Hsp100 chaperones. Analysis of individual mutants for the four Hsp100 chaperones present in Arabidopsis chloroplasts showed increased levels of DXS proteins (but not transcripts) only in those defective in ClpC1 or ClpB3. However, the accumulated enzyme was active in the clpc1 mutant but inactive in clpb3 plants. Genetic evidence indicated that ClpC chaperones might be required for the unfolding of J20-delivered DXS protein coupled to degradation by the Clp protease. By contrast, biochemical and genetic approaches confirmed that Hsp70 and ClpB3 chaperones interact to collaborate in the refolding and activation of DXS. We conclude that specific J-proteins and Hsp100 chaperones act together with Hsp70 to recognize and deliver DXS to either reactivation (via ClpB3) or removal (via ClpC1) depending on the physiological status of the plastid.

  1. Polychlorinated biphenyls in the environment

    International Nuclear Information System (INIS)

    Scheunert, I.; Klein, W.

    1979-08-01

    The report starts with a chapter on occurrence of PCBs in the environment. The next 2 chapters treat synthesis of C-14-labelled PCBs and abiotic conversion of PCBs. The chapter of fate and effects of PCBs in organisms deals with their occurrence in mammals, fish, microorganisms, higher plants and in a defined aquatic ecosystem. The chapter of ecotoxicological profile analysis of PCBs-C-14 presents testing of bioaccumulation, conversion and degradation. (SPI)

  2. Thyrotoxic and dopaminergic effects of polychlorinated biphenyls

    Energy Technology Data Exchange (ETDEWEB)

    Ness, D.K.

    1994-01-01

    Perturbations in the developing nervous system have been associated with perinatal exposures to polychlorinated biphenyls (PCBs). To determine which PCBs accumulate in brain following perinatal exposure, Sprague-Dawley rats were exposed by gavage to Aroclor 1242 (4 or 16 mg/kg/day) during days 10-16 of gestation. At weaning (day 21), analysis of pup brain (frontal cortex, hippocampus, and caudate putamen) by gas chromatography revealed ten peaks representing 10-14 congeners in PCB-exposed animals. Brain PCB concentrations were greatest in high-dose pups for all congeners except for 2,4,4[prime]-trichlorobiphenyl (PCB 28) which had a higher concentration in the low-dose group. Congeners differed significantly in their degree of bioaccumulation, but no significant differences among brain regions were found. A lack of regionalization of PCB residues in the brain was also demonstrated by autoradiography in weanling rats treated iv with [[sup 14]C]-3,3[prime],4,4[prime]-tetrachlorobiphenyl or [[sup 14]C]-2,2[prime],4,4[prime]-tetrachlorobiphenyl. Time-mated Sprague-Dawley rats were exposed on days 10-16 of gestation to three environmentally-relevant PCBs: 2,4,4[prime]-trichlorobiphenyl (PCB 28), 8 or 32 mg/kg/day; 2,3[prime],4,4[prime],5-pentachlorobiphenyl (PCB 118), 4 or 16 mg/kg/day; or 2,2[prime],4,4[prime],5,5[prime]-hexachlorobiphenyl (PCB 153), 16 or 64 mg/kg/day. At weaning, serum total thyroxin, but not triiodothyronine, was markedly depressed in pups exposed perinatally to PCB 118 or 153; and thyroid glands from PCB 118-treated pups revealed histologic changes suggestive of sustained TSH stimulation. No significant PCB-induced changes were detected in the activity of the rate limiting enzyme in the synthesis of catecholamines, tyrosine hydroxylase, in the caudate putamen at weaning or in adulthood. Likewise no significant changes were detected in dopamine receptor (D1 and D2) concentrations in several regions in the mesocortical and nigrostriatal pathways.

  3. Plant enzymes in metabolism of polychlorinated biphenyls

    Czech Academy of Sciences Publication Activity Database

    Chromá, L.; Moeder, M.; Kučerová, P.; Macek, Tomáš; Macková, M.

    2003-01-01

    Roč. 12, č. 3 (2003), s. 291-295 ISSN 1018-4619 R&D Projects: GA MŠk ME 498 Institutional research plan: CEZ:AV0Z4055905 Keywords : polychlorinated biphenyls * plants * peroxidases Subject RIV: CE - Biochemistry Impact factor: 0.325, year: 2003

  4. Characterization of polychlorinated biphenyls in surface sediments ...

    African Journals Online (AJOL)

    The distribution and concentrations of 6 indicator polychlorinated biphenyl (PCB) congeners, nos. 28, 52, 101, 138, 153 and 180, were determined in surface sediments from the North End Lake in Port Elizabeth, South Africa. Forty-two surficial sediment samples were collected from different locations covering the region that ...

  5. 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

  6. Updated Abraham solvation parameters for polychlorinated biphenyls

    NARCIS (Netherlands)

    Noort, van 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

  7. Decomposition of acetaminophen in water by a gas phase dielectric barrier discharge plasma combined with TiO2-rGO nanocomposite: Mechanism and degradation pathway

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Guyu; Sun, Yabing, E-mail: sybnju@163.com; Zhang, Chunxiao; Yu, Zhongqing

    2017-02-05

    Highlights: • Graphene Oxide-based catalyst was first applied with dielectric barrier discharge plasma. • The TiO{sub 2}-rGO showed efficient synergistic effect with gas phase dielectric barrier discharge plasma. • The property changes of TiO{sub 2}-rGO nanocomposite after plasma treatment were characterized. • The mechanism and possible pathways of APAP degradation in plasma/TiO{sub 2}-rGO system were proposed. - Abstract: Acetaminophen (APAP) served as the model pollutant to evaluate the feasibility of pollutant removal by gas phase dielectric barrier discharge plasma combined with the titanium dioxide-reduced Graphene Oxide (TiO{sub 2}-rGO) nanocomposite. TiO{sub 2}-rGO nanocomposite was prepared using the modified hydrothermal method and characterized by TEM and XPS before and after plasma process. The results indicated that the APAP degradation efficiency was significantly improved to 92% after 18 min of discharge plasma treatment coupling 0.25 g L{sup −1} TiO{sub 2}-rGO 5% wt at 18 kV, compared with the plasma alone and plasma combined with P25 TiO{sub 2}. The degradation mechanism for APAP in this system was studied by investigating the effects of the operational variables (e.g. discharge voltage and pH value) and the amount of the generated active species; and the results showed that O{sub 3} and H{sub 2}O{sub 2} yields were influenced notably by adding TiO{sub 2}-rGO. Also, it was observed that, compared with unused TiO{sub 2}-rGO, the photocatalytic performance of used TiO{sub 2}-rGO declined after several recirculation times due to the further reduction of Graphene Oxide in plasma system. Finally, intermediate products were analyzed by UV–vis spectrometry and HPLC/MS, and possible transformation pathways were identified with the support of theoretically calculating the frontier electron density of APAP.

  8. Species-specific diversity of novel bacterial lineages and differential abundance of predicted pathways for toxic compound degradation in scorpion gut microbiota.

    Science.gov (United States)

    Bolaños, Luis M; Rosenblueth, Mónica; Castillo-Ramírez, Santiago; Figuier-Huttin, Gilles; Martínez-Romero, Esperanza

    2016-05-01

    Scorpions are considered 'living fossils' that have conserved ancestral anatomical features and have adapted to numerous habitats. However, their gut microbiota diversity has not been studied. Here, we characterized the gut microbiota of two scorpion species, Vaejovis smithi and Centruroides limpidus. Our results indicate that scorpion gut microbiota is species-specific and that food deprivation reduces bacterial diversity. 16S rRNA gene phylogenetic analysis revealed novel bacterial lineages showing a low level of sequence identity to any known bacteria. Furthermore, these novel bacterial lineages were each restricted to a different scorpion species. Additionally, our results of the predicted metagenomic profiles revealed a core set of pathways that were highly abundant in both species, and mostly related to amino acid, carbohydrate, vitamin and cofactor metabolism. Notably, the food-deprived V. smithi shotgun metagenome matched almost completely the metabolic features of the prediction. Finally, comparisons among predicted metagenomic profiles showed that toxic compound degradation pathways were more abundant in recently captured C. limpidus scorpions. This study gives a first insight into the scorpion gut microbiota and provides a reference for future studies on the gut microbiota from other arachnid species. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  9. Roles of Horizontal Gene Transfer and Gene Integration in Evolution of 1,3-Dichloropropene- and 1,2-Dibromoethane-Degradative Pathways

    Science.gov (United States)

    Poelarends, Gerrit J.; Kulakov, Leonid A.; Larkin, Michael J.; van Hylckama Vlieg, Johan E. T.; Janssen, Dick B.

    2000-01-01

    The haloalkane-degrading bacteria Rhodococcus rhodochrous NCIMB13064, Pseudomonas pavonaceae 170, and Mycobacterium sp. strain GP1 share a highly conserved haloalkane dehalogenase gene (dhaA). Here, we describe the extent of the conserved dhaA segments in these three phylogenetically distinct bacteria and an analysis of their flanking sequences. The dhaA gene of the 1-chlorobutane-degrading strain NCIMB13064 was found to reside within a 1-chlorobutane catabolic gene cluster, which also encodes a putative invertase (invA), a regulatory protein (dhaR), an alcohol dehydrogenase (adhA), and an aldehyde dehydrogenase (aldA). The latter two enzymes may catalyze the oxidative conversion of n-butanol, the hydrolytic product of 1-chlorobutane, to n-butyric acid, a growth substrate for many bacteria. The activity of the dhaR gene product was analyzed in Pseudomonas sp. strain GJ1, in which it appeared to function as a repressor of dhaA expression. The 1,2-dibromoethane-degrading strain GP1 contained a conserved DNA segment of 2.7 kb, which included dhaR, dhaA, and part of invA. A 12-nucleotide deletion in dhaR led to constitutive expression of dhaA in strain GP1, in contrast to the inducible expression of dhaA in strain NCIMB13064. The 1,3-dichloropropene-degrading strain 170 possessed a conserved DNA segment of 1.3 kb harboring little more than the coding region of the dhaA gene. In strains 170 and GP1, a putative integrase gene was found next to the conserved dhaA segment, which suggests that integration events were responsible for the acquisition of these DNA segments. The data indicate that horizontal gene transfer and integrase-dependent gene acquisition were the key mechanisms for the evolution of catabolic pathways for the man-made chemicals 1,3-dichloropropene and 1,2-dibromoethane. PMID:10735862

  10. Roles of horizontal gene transfer and gene integration in evolution of 1,3-dichloropropene- and 1,2-dibromoethane-degradative pathways.

    Science.gov (United States)

    Poelarends, G J; Kulakov, L A; Larkin, M J; van Hylckama Vlieg, J E; Janssen, D B

    2000-04-01

    The haloalkane-degrading bacteria Rhodococcus rhodochrous NCIMB13064, Pseudomonas pavonaceae 170, and Mycobacterium sp. strain GP1 share a highly conserved haloalkane dehalogenase gene (dhaA). Here, we describe the extent of the conserved dhaA segments in these three phylogenetically distinct bacteria and an analysis of their flanking sequences. The dhaA gene of the 1-chlorobutane-degrading strain NCIMB13064 was found to reside within a 1-chlorobutane catabolic gene cluster, which also encodes a putative invertase (invA), a regulatory protein (dhaR), an alcohol dehydrogenase (adhA), and an aldehyde dehydrogenase (aldA). The latter two enzymes may catalyze the oxidative conversion of n-butanol, the hydrolytic product of 1-chlorobutane, to n-butyric acid, a growth substrate for many bacteria. The activity of the dhaR gene product was analyzed in Pseudomonas sp. strain GJ1, in which it appeared to function as a repressor of dhaA expression. The 1,2-dibromoethane-degrading strain GP1 contained a conserved DNA segment of 2.7 kb, which included dhaR, dhaA, and part of invA. A 12-nucleotide deletion in dhaR led to constitutive expression of dhaA in strain GP1, in contrast to the inducible expression of dhaA in strain NCIMB13064. The 1, 3-dichloropropene-degrading strain 170 possessed a conserved DNA segment of 1.3 kb harboring little more than the coding region of the dhaA gene. In strains 170 and GP1, a putative integrase gene was found next to the conserved dhaA segment, which suggests that integration events were responsible for the acquisition of these DNA segments. The data indicate that horizontal gene transfer and integrase-dependent gene acquisition were the key mechanisms for the evolution of catabolic pathways for the man-made chemicals 1, 3-dichloropropene and 1,2-dibromoethane.

  11. Electro-Fenton oxidation of para-aminosalicylic acid: degradation kinetics and mineralization pathway using Pt/carbon-felt and BDD/carbon-felt cells.

    Science.gov (United States)

    Oturan, Nihal; Aravindakumar, Charuvila T; Olvera-Vargas, Hugo; Sunil Paul, Mathew M; Oturan, Mehmet A

    2017-05-31

    Degradation of a widely used antibiotic, the para-aminosalicylic acid (PAS), and mineralization of its aqueous solution was investigated by electro-Fenton process using Pt/carbon-felt and boron-doped diamond (BDD)/carbon-felt cells with applied currents in the range of 50-1000 mA. This process produces the highly oxidizing species, the hydroxyl radical ( • OH), which is mainly responsible for the oxidative degradation of PAS. An absolute rate constant of 4.17 × 10 9  M -1  s -1 for the oxidation of PAS by ● OH was determined from the competition kinetics method. Degradation rate of PAS increased with current reaching an optimal value of 500 mA with complete disappearance of 0.1 mM PAS at 7 min using Pt/carbon-felt cell. The optimum degradation rate was reached at 300 mA for BDD/carbon-felt. The latter cell was found more efficient in total organic carbon (TOC) removal where a complete mineralization was achieved within 240 min. A multi-step mineralization process was observed with the formation of a number of aromatic intermediates, short-chain carboxylic acids, and inorganic ions. Eight aromatic intermediate products were identified using both LC-Q-ToF-MS and GC-MS techniques. These products were the result of hydroxylation of PAS followed by multiple additions of hydroxyl radicals to form polyhydroxylated derivatives. HPLC and GC/MS analyses demonstrated that extended oxidation of these intermediate products conducted to the formation of various short-chain carboxylic acids. Prolonged electrolysis resulted in a complete mineralization of PAS with the evolution of inorganic ions such as NO 3 - and NH 4 + . Based on the identified intermediates, carboxylic acids and inorganic ions, a plausible mineralization pathway is also deduced. The remarkably high degree of mineralization (100%) achieved by the present EF process highlights the potential application of this technique to the complete removal of salicylic acid-based pharmaceuticals from

  12. Combined use of different Gfp reporters for monitoring single-cell activities of a genetically modified PCB degrader in the rhizosphere of alfalfa

    DEFF Research Database (Denmark)

    Boldt, T.S.; Sørensen, J.; Karlsson, U.

    2004-01-01

    Single-cell localization and activity of Pseudomonas,fluorescens F113, colonizing alfalfa roots, were monitored using fusions of the Escherichia coli rrnBP1 ribosomal promoter and gfp genes encoding green fluorescent protein (Gfp) of different stability. The monitoring systems permitted non...... of chlorinated biphenyl was constructed, using another gfp fusion with the meta-pathway Pin promoter from Pseudomonas putida (TOL plasmid). Expression of this promoter, which is strongly induced by the PCB-2 degradation product, 3-chlorobenzoate, was tested in vitro and subsequently monitored in vivo on alfalfa...... roots using the P. fluorescens F113rifpcb reporter. A small but distinct fraction of the introduced bacteria activated the Pm promoter and thus appeared to sense a PCB-2 degradation product in the alfalfa rhizosphere. The degrading cells, which by design were identical to the sensing cells, were located...

  13. IL-1-induced ERK1/2 activation up-regulates p21{sup Waf1/Cip1} protein by inhibition of degradation via ubiquitin-independent pathway in human melanoma cells A375

    Energy Technology Data Exchange (ETDEWEB)

    Arakawa, Tomohiro [Department of Molecular Health Sciences, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603 (Japan); Hayashi, Hidetoshi [Department of Drug Metabolism and Disposition, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603 (Japan); Itoh, Saotomo; Takii, Takemasa [Department of Molecular Health Sciences, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603 (Japan); Onozaki, Kikuo, E-mail: konozaki@phar.nagoya-cu.ac.jp [Department of Molecular Health Sciences, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603 (Japan)

    2010-02-12

    IL-1 inhibits the proliferation of human melanoma cells A375 by arresting the cell cycle at G0/G1 phase, which accompanies the increase of p21{sup Waf1/Cip1} (p21) protein. Here, we demonstrate that IL-1 induces the stabilization of p21 protein via ERK1/2 pathway. The degradation of p21 was inhibited by IL-1, however the ubiquitination level of p21 was not affected. In addition, the degradation of non-ubiquitinated form of lysine less mutant p21-K6R was also inhibited by IL-1, suggesting that IL-1 stabilized p21 protein via ubiquitin-independent pathway. Furthermore, the inhibition of p21 protein degradation was prevented by a selective inhibitor of ERK1/2 pathway, PD98059. These results suggest that IL-1-induced ERK1/2 activation leads to the up-regulation of p21 by inhibiting degradation via ubiquitin-independent pathway in human melanoma cells A375.

  14. Two enzymes of a complete degradation pathway for linear alkylbenzenesulfonate (LAS) surfactants: 4-sulfoacetophenone Baeyer-Villiger monooxygenase and 4-sulfophenylacetate esterase in Comamonas testosteroni KF-1.

    Science.gov (United States)

    Weiss, Michael; Denger, Karin; Huhn, Thomas; Schleheck, David

    2012-12-01

    Complete biodegradation of the surfactant linear alkylbenzenesulfonate (LAS) is accomplished by complex bacterial communities in two steps. First, all LAS congeners are degraded into about 50 sulfophenylcarboxylates (SPC), one of which is 3-(4-sulfophenyl)butyrate (3-C(4)-SPC). Second, these SPCs are mineralized. 3-C(4)-SPC is mineralized by Comamonas testosteroni KF-1 in a process involving 4-sulfoacetophenone (SAP) as a metabolite and an unknown inducible Baeyer-Villiger monooxygenase (BVMO) to yield 4-sulfophenyl acetate (SPAc) from SAP (SAPMO enzyme); hydrolysis of SPAc to 4-sulfophenol and acetate is catalyzed by an unknown inducible esterase (SPAc esterase). Transcriptional analysis showed that one of four candidate genes for BVMOs in the genome of strain KF-1, as well as an SPAc esterase candidate gene directly upstream, was inducibly transcribed during growth with 3-C(4)-SPC. The same genes were identified by enzyme purification and peptide fingerprinting-mass spectrometry when SAPMO was enriched and SPAc esterase purified to homogeneity by protein chromatography. Heterologously overproduced pure SAPMO converted SAP to SPAc and was active with phenylacetone and 4-hydroxyacetophenone but not with cyclohexanone and progesterone. SAPMO showed the highest sequence homology to the archetypal phenylacetone BVMO (57%), followed by steroid BVMO (55%) and 4-hydroxyacetophenone BVMO (30%). Finally, the two pure enzymes added sequentially, SAPMO with NADPH and SAP, and then SPAc esterase, catalyzed the conversion of SAP via SPAc to 4-sulfophenol and acetate in a 1:1:1:1 molar ratio. Hence, the first two enzymes of a complete LAS degradation pathway were identified, giving evidence for the recruitment of members of the very versatile type I BVMO and carboxylester hydrolase enzyme families for the utilization of a xenobiotic compound by bacteria.

  15. Gamma-Glutamylpolyamine Synthetase GlnA3 Is Involved in the First Step of Polyamine Degradation Pathway in Streptomyces coelicolor M145

    Directory of Open Access Journals (Sweden)

    Agnieszka Bera

    2017-04-01

    Full Text Available Streptomyces coelicolor M145 was shown to be able to grow in the presence of high concentrations of polyamines, such as putrescine, cadaverine, spermidine, or spermine, as a sole nitrogen source. However, hardly anything is known about polyamine utilization and its regulation in streptomycetes. In this study, we demonstrated that only one of the three proteins annotated as glutamine synthetase-like protein, GlnA3 (SCO6962, was involved in the catabolism of polyamines. Transcriptional analysis revealed that the expression of glnA3 was strongly induced by exogenous polyamines and repressed in the presence of ammonium. The ΔglnA3 mutant was shown to be unable to grow on defined Evans agar supplemented with putrescine, cadaverine, spermidine, and spermine as sole nitrogen source. HPLC analysis demonstrated that the ΔglnA3 mutant accumulated polyamines intracellularly, but was unable to degrade them. In a rich complex medium supplemented with a mixture of the four different polyamines, the ΔglnA3 mutant grew poorly showing abnormal mycelium morphology and decreased life span in comparison to the parental strain. These observations indicated that the accumulation of polyamines was toxic for the cell. An in silico analysis of the GlnA3 protein model suggested that it might act as a gamma-glutamylpolyamine synthetase catalyzing the first step of polyamine degradation. GlnA3-catalyzed glutamylation of putrescine was confirmed in an enzymatic in vitro assay and the GlnA3 reaction product, gamma-glutamylputrescine, was detected by HPLC/ESI-MS. In this work, the first step of polyamine utilization in S. coelicolor has been elucidated and the putative polyamine utilization pathway has been deduced based on the sequence similarity and transcriptional analysis of homologous genes expressed in the presence of polyamines.

  16. Diphenylarsinic acid contaminated soil remediation by titanium dioxide (P25) photocatalysis: Degradation pathway, optimization of operating parameters and effects of soil properties

    International Nuclear Information System (INIS)

    Wang, A-nan; Teng, Ying; Hu, Xue-feng; Wu, Long-hua; Huang, Yu-juan; Luo, Yong-ming; Christie, Peter

    2016-01-01

    Diphenylarsinic acid (DPAA) is formed during the leakage of arsenic chemical weapons in sites and poses a high risk to biota. However, remediation methods for DPAA contaminated soils are rare. Here, the photocatalytic oxidation (PCO) process by nano-sized titanium dioxide (TiO 2 ) was applied to degrade DPAA in soil. The degradation pathway was firstly studied, and arsenate was identified as the final product. Then, an orthogonal array experimental design of L 9 (3) 4 , only 9 experiments were needed, instead of 81 experiments in a conventional one-factor-at-a-time, was used to optimize the operational parameters soil:water ratio, TiO 2 dosage, irradiation time and light intensity to increase DPAA removal efficiency. Soil:water ratio was found to have a more significant effect on DPAA removal efficiency than other properties. The optimum conditions to treat 4 g soil with a DPAA concentration of 20 mg kg −1 were found to be a 1:10 soil: water ratio, 40 mW cm −2 light intensity, 5% TiO 2 in soil, and a 3-hour irradiation time, with a removal efficiency of up to 82.7%. Furthermore, this method (except for a change in irradiation time from 3 to 1.5 h) was validated in nine different soils and the removal efficiencies ranged from 57.0 to 78.6%. Removal efficiencies were found to be negatively correlated with soil electrical conductivity, organic matter content, pH and total phosphorus content. Finally, coupled with electron spin resonance (ESR) measurement, these soil properties affected the generation of OH• by TiO 2 in soil slurry. This study suggests that TiO 2 photocatalytic oxidation is a promising treatment for removing DPAA from soil. - Highlights: • DPAA was degraded into arsenate through TiO 2 (P25) photocatalytic oxidation. • Soil/water ratio was more influential on the removal of DPAA in soil by TiO 2 (P25). • Soil properties affected the adsorption of DPAA and the generation of OH• by TiO 2 .

  17. A putrescine-inducible pathway comprising PuuE-YneI in which gamma-aminobutyrate is degraded into succinate in Escherichia coli K-12.

    Science.gov (United States)

    Kurihara, Shin; Kato, Kenji; Asada, Kei; Kumagai, Hidehiko; Suzuki, Hideyuki

    2010-09-01

    Gamma-aminobutyrate (GABA) is metabolized to succinic semialdehyde by GABA aminotransferase (GABA-AT), and the succinic semialdehyde is subsequently oxidized to succinate by succinic semialdehyde dehydrogenase (SSADH). In Escherichia coli, there are duplicate GABA-ATs (GabT and PuuE) and duplicate SSADHs (GabD and YneI). While GabT and GabD have been well studied previously, the characterization and expression analysis of PuuE and YneI are yet to be investigated. By analyzing the amino acid profiles in cells of DeltapuuE and/or DeltagabT mutants, this study demonstrated that PuuE plays an important role in GABA metabolism in E. coli cells. The similarity of the amino acid sequences of PuuE and GabT is 67.4%, and it was biochemically demonstrated that the catalytic center of GabT is conserved as an amino acid residue important for the enzymatic activity in PuuE as Lys-247. However, the regulation of expression of PuuE is significantly different from that of GabT. PuuE is induced by the addition of putrescine to the medium and is repressed by succinate and low aeration conditions; in contrast, GabT is almost constitutive. Similarly, YneI is induced by putrescine, while GabD is not. For E. coli, PuuE is important for utilization of putrescine as a sole nitrogen source and both PuuE and YneI are important for utilization of putrescine as a sole carbon source. The results demonstrate that the PuuE-YneI pathway was a putrescine-inducible GABA degradation pathway for utilizing putrescine as a nutrient source.

  18. A Putrescine-Inducible Pathway Comprising PuuE-YneI in Which γ-Aminobutyrate Is Degraded into Succinate in Escherichia coli K-12▿

    Science.gov (United States)

    Kurihara, Shin; Kato, Kenji; Asada, Kei; Kumagai, Hidehiko; Suzuki, Hideyuki

    2010-01-01

    γ-Aminobutyrate (GABA) is metabolized to succinic semialdehyde by GABA aminotransferase (GABA-AT), and the succinic semialdehyde is subsequently oxidized to succinate by succinic semialdehyde dehydrogenase (SSADH). In Escherichia coli, there are duplicate GABA-ATs (GabT and PuuE) and duplicate SSADHs (GabD and YneI). While GabT and GabD have been well studied previously, the characterization and expression analysis of PuuE and YneI are yet to be investigated. By analyzing the amino acid profiles in cells of ΔpuuE and/or ΔgabT mutants, this study demonstrated that PuuE plays an important role in GABA metabolism in E. coli cells. The similarity of the amino acid sequences of PuuE and GabT is 67.4%, and it was biochemically demonstrated that the catalytic center of GabT is conserved as an amino acid residue important for the enzymatic activity in PuuE as Lys-247. However, the regulation of expression of PuuE is significantly different from that of GabT. PuuE is induced by the addition of putrescine to the medium and is repressed by succinate and low aeration conditions; in contrast, GabT is almost constitutive. Similarly, YneI is induced by putrescine, while GabD is not. For E. coli, PuuE is important for utilization of putrescine as a sole nitrogen source and both PuuE and YneI are important for utilization of putrescine as a sole carbon source. The results demonstrate that the PuuE-YneI pathway was a putrescine-inducible GABA degradation pathway for utilizing putrescine as a nutrient source. PMID:20639325

  19. The comparative photodegradation activities of pentachlorophenol (PCP and polychlorinated biphenyls (PCBs using UV alone and TiO2-derived photocatalysts in methanol soil washing solution.

    Directory of Open Access Journals (Sweden)

    Zeyu Zhou

    Full Text Available Photochemical treatment is increasingly being applied to remedy environmental problems. TiO2-derived catalysts are efficiently and widely used in photodegradation applications. The efficiency of various photochemical treatments, namely, the use of UV irradiation without catalyst or with TiO2/graphene-TiO2 photodegradation methods was determined by comparing the photodegadation of two main types of hydrophobic chlorinated aromatic pollutants, namely, pentachlorophenol (PCP and polychlorinated biphenyls (PCBs. Results show that photodegradation in methanol solution under pure UV irradiation was more efficient than that with either one of the catalysts tested, contrary to previous results in which photodegradation rates were enhanced using TiO2-derived catalysts. The effects of various factors, such as UV light illumination, addition of methanol to the solution, catalyst dosage, and the pH of the reaction mixture, were examined. The degradation pathway was deduced. The photochemical treatment in methanol soil washing solution did not benefit from the use of the catalysts tested. Pure UV irradiation was sufficient for the dechlorination and degradation of the PCP and PCBs.

  20. The Quest for Converting Biorenewable Bifunctional α-Methylene-γ-butyrolactone into Degradable and Recyclable Polyester: Controlling Vinyl-Addition/Ring-Opening/Cross-Linking Pathways

    KAUST Repository

    Tang, Xiaoyan

    2016-10-04

    α-Methylene-γ-butyrolactone (MBL), a naturally occurring and biomass-sourced bifunctional monomer, contains both a highly reactive exocyclic C═C bond and a highly stable five-membered γ-butyrolactone ring. Thus, all previous work led to exclusive vinyl-addition polymerization (VAP) product P(MBL)VAP. Now, this work reverses this conventional chemoselectivity to enable the first ring-opening polymerization (ROP) of MBL, thereby producing exclusively unsaturated polyester P(MBL)ROP with Mn up to 21.0 kg/mol. This elusive goal was achieved through uncovering the thermodynamic, catalytic, and processing conditions. A third reaction pathway has also been discovered, which is a crossover propagation between VAP and ROP processes, thus affording cross-linked polymer P(MBL)CLP. The formation of the three types of polymers, P(MBL)VAP, P(MBL)CLP, and P(MBL)ROP, can be readily controlled by adjusting the catalyst (La)/initiator (ROH) ratio, which is determined by the unique chemoselectivity of the La–X (X = OR, NR2, R) group. The resulting P(MBL)ROP is degradable and can be readily postfunctionalized into cross-linked or thiolated materials but, more remarkably, can also be fully recycled back to its monomer thermochemically. Computational studies provided the theoretical basis for, and a mechanistic understanding of, the three different polymerization processes and the origin of the chemoselectivity.

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

    OpenAIRE

    Kim, Hyeon-Yeong; Shin, Sae-Mi; Ham, Miran; Lim, Cheol-Hong; Byeon, Sang-Hoon

    2015-01-01

    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 ma...

  2. O legado das bifenilas policloradas (PCBs The legacy of the polychlorinated biphenyls (PCBs

    Directory of Open Access Journals (Sweden)

    José Carlos Pires Penteado

    2001-06-01

    Full Text Available Polychlorinated biphenyls (PCBs are a class of 209 chemical compounds with the molecular formula C12H10-nCl n, where 1 <= n <= 10. They were commercially produced as complex mixtures for various uses, being employed principally as dielectric fluids in capacitors and transformers. They are not easily degraded due their chemical and physical stability and tend to bioaccumulate in the organisms. After the discovery of their xenobiotic activity, restrictions were imposed for their use, as well as for their discards. Nowadays the development of recovery processes for contaminated environment urges to be done due to the extension of reached areas.

  3. Disulfiram/copper-disulfiram Damages Multiple Protein Degradation and Turnover Pathways and Cytotoxicity is Enhanced by Metformin in Oesophageal Squamous Cell Carcinoma Cell Lines.

    Science.gov (United States)

    Jivan, Rupal; Damelin, Leonard Howard; Birkhead, Monica; Rousseau, Amanda Louise; Veale, Robin Bruce; Mavri-Damelin, Demetra

    2015-10-01

    Disulfiram (DSF), used since the 1950s in the treatment of alcoholism, is reductively activated to diethyldithiocarbamate and both compounds are thiol-reactive and readily complex copper. More recently DSF and copper-DSF (Cu-DSF) have been found to exhibit potent anticancer activity. We have previously shown that the anti-diabetic drug metformin is anti-proliferative and induces an intracellular reducing environment in oesophageal squamous cell carcinoma (OSCC) cell lines. Based on these observations, we investigated the effects of Cu-DSF and DSF, with and without metformin, in this present study. We found that Cu-DSF and DSF caused considerable cytotoxicity across a panel of OSCC cells, and metformin significantly enhanced the effects of DSF. Elevated copper transport contributes to DSF and metformin-DSF-induced cytotoxicity since the cell-impermeable copper chelator, bathocuproinedisulfonic acid, partially reversed the cytotoxic effects of these drugs, and interestingly, metformin-treated OSCC cells contained higher intracellular copper levels. Furthermore, DSF may target cancer cells preferentially due to their high dependence on protein degradation/turnover pathways, and we found that metformin further enhances the role of DSF as a proteasome inhibitor. We hypothesized that the lysosome could be an additional, novel, target of DSF. Indeed, this acid-labile compound decreased lysosomal acidification, and DSF-metformin co-treatment interfered with the progression of autophagy in these cells. In summary, this is the first such report identifying the lysosome as a target of DSF and based on the considerable cytotoxic effects of DSF either alone or in the presence of metformin, in vitro, and we propose these as novel potential chemotherapeutic approaches for OSCC. © 2015 Wiley Periodicals, Inc.

  4. Overexpression of alpha-synuclein at non-toxic levels increases dopaminergic cell death induced by copper exposure via modulation of protein degradation pathways.

    Science.gov (United States)

    Anandhan, Annadurai; Rodriguez-Rocha, Humberto; Bohovych, Iryna; Griggs, Amy M; Zavala-Flores, Laura; Reyes-Reyes, Elsa M; Seravalli, Javier; Stanciu, Lia A; Lee, Jaekwon; Rochet, Jean-Christophe; Khalimonchuk, Oleh; Franco, Rodrigo

    2015-09-01

    Gene multiplications or point mutations in alpha (α)-synuclein are associated with familial and sporadic Parkinson's disease (PD). An increase in copper (Cu) levels has been reported in the cerebrospinal fluid and blood of PD patients, while occupational exposure to Cu has been suggested to augment the risk to develop PD. We aimed to elucidate the mechanisms by which α-synuclein and Cu regulate dopaminergic cell death. Short-term overexpression of wild type (WT) or mutant A53T α-synuclein had no toxic effect in human dopaminergic cells and primary midbrain cultures, but it exerted a synergistic effect on Cu-induced cell death. Cell death induced by Cu was potentiated by overexpression of the Cu transporter protein 1 (Ctr1) and depletion of intracellular glutathione (GSH) indicating that the toxic effects of Cu are linked to alterations in its intracellular homeostasis. Using the redox sensor roGFP, we demonstrated that Cu-induced oxidative stress was primarily localized in the cytosol and not in the mitochondria. However, α-synuclein overexpression had no effect on Cu-induced oxidative stress. WT or A53T α-synuclein overexpression exacerbated Cu toxicity in dopaminergic and yeast cells in the absence of α-synuclein aggregation. Cu increased autophagic flux and protein ubiquitination. Impairment of autophagy by overexpression of a dominant negative Atg5 form or inhibition of the ubiquitin/proteasome system (UPS) with MG132 enhanced Cu-induced cell death. However, only inhibition of the UPS stimulated the synergistic toxic effects of Cu and α-synuclein overexpression. Our results demonstrate that α-synuclein stimulates Cu toxicity in dopaminergic cells independent from its aggregation via modulation of protein degradation pathways. Copyright © 2014 Elsevier Inc. All rights reserved.

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

    OpenAIRE

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

    2003-01-01

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

  6. 40 CFR 129.105 - Polychlorinated biphenyls (PCBs).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 21 2010-07-01 2010-07-01 false Polychlorinated biphenyls (PCBs). 129.105 Section 129.105 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS TOXIC POLLUTANT EFFLUENT STANDARDS Toxic Pollutant Effluent Standards and Prohibitions § 129.105 Polychlorinated biphenyls (PCBs). (a)...

  7. Phytoremediation of soil contaminated with cadmium, copper and polychlorinated biphenyls.

    Science.gov (United States)

    Wu, Longhua; Li, Zhu; Han, Cunliang; Liu, Ling; Teng, Ying; Sun, Xianghui; Pan, Cheng; Huang, Yujuan; Luo, Yongming; Christie, Peter

    2012-07-01

    A pot experiment and afield trial were conducted to study the remediation of an aged field soil contaminated with cadmium, copper and polychlorinated biphenyls (PCBs) (7.67 +/- 0.51 mg kg(-1) Cd, 369 +/- 1 mg kg(-1) Cu in pot experiment; 8.46 +/- 0.31 mg kg(-1) Cd, 468 +/- 7 mg kg(-1) Cu, 323 +/- 12 microg kg(-1) PCBs for field experiment) under different cropping patterns. In the pot experiment Sedum plumbizincicola showed pronounced Cd phytoextraction. After two periods (14 months) of cropping the Cd removal rates in these two treatments were 52.2 +/- 12.0 and 56.1 +/- 9.1%, respectively. Total soil PCBs in unplanted control pots decreased from 323 +/- 11 to 49.3 +/- 6.6 microg kg(-1), but with no significant difference between treatments. The field microcosm experiment intercropping of three plant species reduced the yield of S. plumbizincicola, with a consequent decrease in soil Cd removal. S. plumbizincicola intercropped with E. splendens had the highest shoot Cd uptake (18.5 +/- 1.8 mg pot(-1)) after 6 months planting followed by intercropping with M. sativa (15.9 +/- 1.9 mg pot(-1)). Liming with S. plumbizincicola intercropped with M. sativa significantly promoted soil PCB degradation by 25.2%. Thus, adjustment of soil pH to 5.56 combined with intercropping with S. plumbizincicola and M. sativagave high removal rates of Cd, Cu, and PCBs.

  8. Removal of antibiotic cloxacillin by means of electrochemical oxidation, TiO2photocatalysis, and photo-Fenton processes: analysis of degradation pathways and effect of the water matrix on the elimination of antimicrobial activity.

    Science.gov (United States)

    Serna-Galvis, Efraim A; Giraldo-Aguirre, Ana L; Silva-Agredo, Javier; Flórez-Acosta, Oscar A; Torres-Palma, Ricardo A

    2017-03-01

    This study evaluates the treatment of the antibiotic cloxacillin (CLX) in water by means of electrochemical oxidation, TiO 2 photocatalysis, and the photo-Fenton system. The three treatments completely removed cloxacillin and eliminated the residual antimicrobial activity from synthetic pharmaceutical wastewater containing the antibiotic, commercial excipients, and inorganic ions. However, significant differences in the degradation routes were found. In the photo-Fenton process, the hydroxyl radical was involved in the antibiotic removal, while in the TiO 2 photocatalysis process, the action of both the holes and the adsorbed hydroxyl radicals degraded the pollutant. In the electrochemical treatment (using a Ti/IrO 2 anode in sodium chloride as supporting electrolyte), oxidation via HClO played the main role in the removal of CLX. The analysis of initial by-products showed five different mechanistic pathways: oxidation of the thioether group, opening of the central β-lactam ring, breakdown of the secondary amide, hydroxylation of the aromatic ring, and decarboxylation. All the oxidation processes exhibited the three first pathways. Moreover, the aromatic ring hydroxylation was found in both photochemical treatments, while the decarboxylation of the pollutant was only observed in the TiO 2 photocatalysis process. As a consequence of the degradation routes and mechanistic pathways, the elimination of organic carbon was different. After 480 and 240 min, the TiO 2 photocatalysis and photo-Fenton processes achieved ∼45 and ∼15 % of mineralization, respectively. During the electrochemical treatment, 100 % of the organic carbon remained even after the antibiotic was treated four times the time needed to degrade it. In contrast, in all processes, a natural matrix (mineral water) did not considerably inhibit pollutant elimination. However, the presence of glucose in the water significantly affected the degradation of CLX by means of TiO 2 photocatalysis.

  9. Chemical Conversion Pathways and Kinetic Modeling for the OH-Initiated Reaction of Triclosan in Gas-Phase

    Directory of Open Access Journals (Sweden)

    Xue Zhang

    2015-04-01

    Full Text Available As a widely used antimicrobial additive in daily consumption, attention has been paid to the degradation and conversion of triclosan for a long time. The quantum chemistry calculation and the canonical variational transition state theory are employed to investigate the mechanism and kinetic property. Besides addition and abstraction, oxidation pathways and further conversion pathways are also considered. The OH radicals could degrade triclosan to phenols, aldehydes, and other easily degradable substances. The conversion mechanisms of triclosan to the polychlorinated dibenzopdioxin and furan (PCDD/Fs and polychlorinated biphenyls (PCBs are clearly illustrated and the toxicity would be strengthened in such pathways. Single radical and diradical pathways are compared to study the conversion mechanism of dichlorodibenzo dioxin (DCDD. Furthermore, thermochemistry is discussed in detail. Kinetic property is calculated and the consequent ratio of kadd/ktotal and kabs/ktotal at 298.15 K are 0.955 and 0.045, respectively. Thus, the OH radical addition reactions are predominant, the substitute position of OH radical on triclosan is very important to generate PCDD and furan, and biradical is also a vital intermediate to produce dioxin.

  10. RADIATION DEGRADATION OF PCBS IN SEDIMENTS: COMPARISON OF TWO METHODS

    Directory of Open Access Journals (Sweden)

    Ľubica Darážová

    2016-12-01

    Full Text Available Polychlorinated biphenyls are toxic compounds which have accumulated in river sediments in Eastern Slovakia. Bioaccumulation could cause even cancer. Radiation degradation with electrons is new and perspective method to dechlorinate PCBs in sediment matrix. We tested the influence of two difference chemical pretreatments and electron irradiation on PCB contaminated sediments.

  11. Escherichia coli phnN, encoding ribose 1,5-bisphosphokinase activity (phosphoribosyl diphosphate forming): dual role in phosphonate degradation and NAD biosynthesis pathways

    DEFF Research Database (Denmark)

    Hove-Jensen, Bjarne; Rosenkrantz, Tina J; Haldimann, Andreas

    2003-01-01

    An enzymatic pathway for synthesis of 5-phospho-D-ribosyl alpha-1-diphosphate (PRPP) without the participation of PRPP synthase was analyzed in Escherichia coli. This pathway was revealed by selection for suppression of the NAD requirement of strains with a deletion of the prs gene, the gene...

  12. 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...

  13. 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) blueÂżsh collected in the vicinity...

  14. Degradation Network Reconstruction in Uric Acid and Ammonium Amendments in Oil-Degrading Marine Microcosms Guided by Metagenomic Data

    KAUST Repository

    Bargiela, Rafael

    2015-11-24

    Biostimulation with different nitrogen sources is often regarded as a strategy of choice in combating oil spills in marine environments. Such environments are typically depleted in nitrogen, therefore limiting the balanced microbial utilization of carbon-rich petroleum constituents. It is fundamental, yet only scarcely accounted for, to analyze the catabolic consequences of application of biostimulants. Here, we examined such alterations in enrichment microcosms using sediments from chronically crude oil-contaminated marine sediment at Ancona harbor (Italy) amended with natural fertilizer, uric acid (UA), or ammonium (AMM). We applied the web-based AromaDeg resource using as query Illumina HiSeq meta-sequences (UA: 27,893 open reading frames; AMM: 32,180) to identify potential catabolic differences. A total of 45 (for UA) and 65 (AMM) gene sequences encoding key catabolic enzymes matched AromaDeg, and their participation in aromatic degradation reactions could be unambiguously suggested. Genomic signatures for the degradation of aromatics such as 2-chlorobenzoate, indole-3-acetate, biphenyl, gentisate, quinoline and phenanthrene were common for both microcosms. However, those for the degradation of orcinol, ibuprofen, phenylpropionate, homoprotocatechuate and benzene (in UA) and 4-aminobenzene-sulfonate, p-cumate, dibenzofuran and phthalate (in AMM), were selectively enriched. Experimental validation was conducted and good agreement with predictions was observed. This suggests certain discrepancies in action of these biostimulants on the genomic content of the initial microbial community for the catabolism of petroleum constituents or aromatics pollutants. In both cases, the emerging microbial communities were phylogenetically highly similar and were composed by very same proteobacterial families. However, examination of taxonomic assignments further revealed different catabolic pathway organization at the organismal level, which should be considered for designing

  15. Degradation network reconstruction in uric acid and ammonium amendments in oil-degrading marine microcosms guided by metagenomic data

    Directory of Open Access Journals (Sweden)

    Rafael eBargiela

    2015-11-01

    Full Text Available Biostimulation with different nitrogen sources is often regarded as a strategy of choice in combating oil spills in marine environments. Such environments are typically depleted in nitrogen, therefore limiting the balanced microbial utilization of carbon-rich petroleum constituents. It is fundamental, yet only scarcely accounted for, to analyse the catabolic consequences of application of biostimulants. Here, we examined such alterations in enrichment microcosms using sediments from chronically crude oil-contaminated marine sediment at Ancona harbor (Italy amended with natural fertilizer, uric acid (UA, or ammonium (AMM. We applied the web-based AromaDeg resource using as query Illumina HiSeq meta-sequences (UA: 27,893 open reading frames; AMM: 32,180 to identify potential catabolic differences. A total of 45 (for UA and 65 (AMM gene sequences encoding key catabolic enzymes matched AromaDeg, and their participation in aromatic degradation reactions could be unambiguously suggested. Genomic signatures for the degradation of aromatics such as 2-chlorobenzoate, indole-3-acetate, biphenyl, gentisate, quinoline and phenanthrene were common for both microcosms. However, those for the degradation of orcinol, ibuprofen, phenylpropionate, homoprotocatechuate and benzene (in UA and 4-aminobenzene-sulfonate, p-cumate, dibenzofuran and phthalate (in AMM, were selectively enriched. Experimental validation was conducted and good agreement with predictions was observed. This suggests certain discrepancies in action of these biostimulants on the genomic content of the initial microbial community for the catabolism of petroleum constituents or aromatics pollutants. In both cases, the emerging microbial communities were phylogenetically highly similar and were composed by very same proteobacterial families. However, examination of taxonomic assignments further revealed different catabolic pathway organization at the organismal level, which should be considered

  16. 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.

  17. Estimation of polychlorinated biphenyl fugacity ratios.

    Science.gov (United States)

    Van Noort, Paul C M

    2006-11-01

    On the quantitative comparison of solubilities or vapor pressures of homologous series, the variation in the effect of crystal structure on solid properties may substantially influence the outcome of the comparison. Usually, the effect of this variation is eliminated by comparing values of the liquid state. The ratio of solid to liquid properties is called the fugacity ratio. Fugacity ratios are usually calculated from fusion thermodynamic data. For 41 polychlorinated biphenyls (PCBs), fusion enthalpy was found to be correlated with fusion entropy. Highly linear correlations were observed for non-ortho-PCBs, mono-ortho-PCBs, and diortho-PCBs. Fugacity ratios estimated from the fusion enthalpy-entropy linear regression parameters were equal, within 10% on average, to fugacity ratios calculated from fusion enthalpy for ortho chlorinated PCBs with melting points below 380 K and for non-ortho-PCBs. For ortho chlorinated PCBs with melting points above 380 K, fugacity ratios were better estimated from a nonlinear regression of fugacity ratios against the melting point and the system temperature. For all 209 PCB congeners, fugacity ratios at 298 K are listed on the basis of experimental fusion data or estimates from the regressions.

  18. Inadvertent polychlorinated biphenyls in commercial paint pigments.

    Science.gov (United States)

    Hu, Dingfei; Hornbuckle, Keri C

    2010-04-15

    A polychlorinated biphenyl (PCB) that was not produced as part of the Aroclor mixtures banned in the 1980s was recently reported in air samples collected in Chicago, Philadelphia, the Arctic, and several sites around the Great Lakes. In Chicago, the congener 3,3'-dichlorobiphenyl or PCB11 was found to be the fifth most concentrated congener and ubiquitous throughout the city. The congener exhibited strong seasonal concentration trends that suggest volatilization of this compound from common outdoor surfaces. Due to these findings and also the compound's presence in waters that received waste from paint manufacturing facilities, we hypothesized that PCB11 may be present in current commercial paint. In this study we measured PCBs in paint sold on the current retail market. We tested 33 commercial paint pigments purchased from three local paint stores. The pigment samples were analyzed for all 209 PCB congeners using gas chromatography with tandem mass spectrometry (GC-MS/MS). More than 50 PCB congeners including several dioxin-like PCBs were detected, and the PCB profiles varied due to different types of pigments and different manufacturing processes. PCB congeners were detected in azo and phthalocyanine pigments which are commonly used in paint but also in inks, textiles, paper, cosmetics, leather, plastics, food and other materials. Our findings suggest several possible mechanisms for the inadvertent production of specific PCB congeners during the manufacturing of paint pigments.

  19. Inadvertent Polychlorinated Biphenyls in Commercial Paint Pigments†

    Science.gov (United States)

    2009-01-01

    A polychlorinated biphenyl (PCB) that was not produced as part of the Aroclor mixtures banned in the 1980s was recently reported in air samples collected in Chicago, Philadelphia, the Arctic, and several sites around the Great Lakes. In Chicago, the congener 3,3′-dichlorobiphenyl or PCB11 was found to be the fifth most concentrated congener and ubiquitous throughout the city. The congener exhibited strong seasonal concentration trends that suggest volatilization of this compound from common outdoor surfaces. Due to these findings and also the compound’s presence in waters that received waste from paint manufacturing facilities, we hypothesized that PCB11 may be present in current commercial paint. In this study we measured PCBs in paint sold on the current retail market. We tested 33 commercial paint pigments purchased from three local paint stores. The pigment samples were analyzed for all 209 PCB congeners using gas chromatography with tandem mass spectrometry (GC-MS/MS). More than 50 PCB congeners including several dioxin-like PCBs were detected, and the PCB profiles varied due to different types of pigments and different manufacturing processes. PCB congeners were detected in azo and phthalocyanine pigments which are commonly used in paint but also in inks, textiles, paper, cosmetics, leather, plastics, food and other materials. Our findings suggest several possible mechanisms for the inadvertent production of specific PCB congeners during the manufacturing of paint pigments. PMID:19957996

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

    Czech Academy of Sciences Publication Activity Database

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

    2004-01-01

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

  1. Exogenous Melatonin Suppresses Dark-Induced Leaf Senescence by Activating the Superoxide Dismutase-Catalase Antioxidant Pathway and Down-Regulating Chlorophyll Degradation in Excised Leaves of Perennial Ryegrass (Lolium perenneL.).

    Science.gov (United States)

    Zhang, Jing; Li, Huibin; Xu, Bin; Li, Jing; Huang, Bingru

    2016-01-01

    Leaf senescence is a typical symptom in plants exposed to dark and may be regulated by plant growth regulators. The objective of this study was to determine whether exogenous application of melatonin (N-acetyl-5-methoxytryptamine) suppresses dark-induced leaf senescence and the effects of melatonin on reactive oxygen species (ROS) scavenging system and chlorophyll degradation pathway in perennial grass species. Mature perennial ryegrass ( Lolium perenne L. cv. 'Pinnacle') leaves were excised and incubated in 3 mM 2-(N-morpholino) ethanesulfonic buffer (pH 5.8) supplemented with melatonin or water (control) and exposed to dark treatment for 8 days. Leaves treated with melatonin maintained significantly higher endogenous melatonin level, chlorophyll content, photochemical efficiency, and cell membrane stability expressed by lower electrolyte leakage and malondialdehyde (MDA) content compared to the control. Exogenous melatonin treatment also reduced the transcript level of chlorophyll degradation-associated genes and senescence marker genes ( LpSAG12.1 , Lph36 , and Lpl69 ) during the dark treatment. The endogenous O 2 - production rate and H 2 O 2 content were significantly lower in these excised leaves treated with melatonin compared to the water control. Exogenous melatonin treatment caused increases in enzymatic activity and transcript levels of superoxide dismutase and catalase but had no significant effects on ascorbate peroxidase, glutathione reductase, dehydroascorbate reductase, and monohydroascorbate reductase. The content of non-enzymatic antioxidants, such as ascorbate and dehydroascorbate, were decreased by melatonin treatment, while the content of glutathione and oxidized glutathione was not affected by melatonin. These results suggest that the suppression of dark-induced leaf senescence by exogenous melatonin may be associated with its roles in regulating ROS scavenging through activating the superoxide dismutase-catalase enzymatic antioxidant pathway

  2. Exogenous melatonin suppresses dark-induced leaf senescence by activating the superoxide dismutase-catalase antioxidant pathway and down-regulating chlorophyll degradation in excised leaves of perennial ryegrass (Lolium perenne L.

    Directory of Open Access Journals (Sweden)

    Jing Zhang

    2016-10-01

    Full Text Available Leaf senescence is a typical symptom in plants exposed to dark and may be regulated by plant growth regulators. The objective of this study was to determine whether exogenous application of melatonin (N-acetyl-5-methoxytryptamine suppresses dark-induced leaf senescence and the effects of melatonin on reactive oxygen species (ROS scavenging system and chlorophyll degradation pathway in perennial grass species. Mature perennial ryegrass (Lolium perenne L. cv. ‘Pinnacle’ leaves were excised and incubated in 3 mM 2-(N-morpholino ethanesulfonic buffer (pH 5.8 supplemented with melatonin or water (control and exposed to dark treatment for 8 d. Leaves treated with melatonin maintained significantly higher endogenous melatonin level, chlorophyll content, photochemical efficiency, and cell membrane stability expressed by lower electrolyte leakage and malondialdehyde (MDA content compared to the control. Exogenous melatonin treatment also reduced the transcript level of chlorophyll degradation-associated genes and senescence marker genes (LpSAG12.1, Lph36, and Lpl69 during the dark treatment. The endogenous O2- production rate and H2O2 content were significantly lower in these excised leaves treated with melatonin compared to the water control. Exogenous melatonin treatment caused increases in enzymatic activity and transcript levels of superoxide dismutase and catalase but had no significant effects on ascorbate peroxidase, glutathione reductase, dehydroascorbate reductase, and monohydroascorbate reductase. The content of non-enzymatic antioxidants, such as ascorbate and dehydroascorbate, were decreased by melatonin treatment, while the content of glutathione and oxidized glutathione was not affected by melatonin. These results suggest that the suppression of dark-induced leaf senescence by exogenous melatonin may be associated with its roles in regulating ROS scavenging through activating the superoxide dismutase-catalase enzymatic antioxidant

  3. Polychlorinated biphenyls – toxicity and risks

    Directory of Open Access Journals (Sweden)

    Ivana Kmetič

    2012-01-01

    Full Text Available Polychlorinated biphenyls (PCBs are synthetic organochlorine compounds differing by their physico-chemical and toxicological properties and tend to bioaccumulate and biomagnificate in the environment and within the food chain. Consequently, humans may be exposed through contaminated drinking water and food, mainly fish, meat and dairy products. Production and usage of PCBs are restricted according to legislation and preventive measures in most of EU countries. In the Republic of Croatia the risk is still present due to military activities during the Patriotic War (1991-1995 when the industrial, electric power and other facilities were largely damaged resulting in leakage of PCBs. Therefore, it is necessary to develop and implement further strategies for identifying contaminated sites and for their remediation in an environmentally sound manner. Additionally, there is a need for safe disposal of PCBs sources including stepwise monitoring of persistent organic pollutants (POPs level in accordance with Croatian national plan for implementation of the Stockholm Convention. So far, numerous researches indicate a variety of adverse effects of PCBs on human health, such as immunotoxicity, neurotoxicity and genotoxicity. Many of these compounds are potential endocrine disrupters causing reproductive dysfunctions. Toxic properties and potencies of PCB congeners generally depend upon the presence of chlorine atom in ortho position, whereas planar non-ortho- and mono-ortho-substituted PCB congeners are considered to be more toxic. Structural similarities between planar congeners and dioxins explain their mechanism of action mediated through the aryl hydrocarbon receptor (AhR, while non-planar PCBs appear to be weak antagonists of AhR. Some of PCBs' toxic effects are not resulting from the AhR activation, e.g. ortho-substituted PCBs can cause toxicity by other mechanisms. Influence of PCBs on human health and on health of certain members of the populations

  4. 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.

  5. Transcriptional response of Rhodococcus aetherivorans I24 to polychlorinated biphenyl-contaminated sediments.

    Science.gov (United States)

    Puglisi, Edoardo; Cahill, Matt J; Lessard, Philip A; Capri, Ettore; Sinskey, Anthony J; Archer, John A C; Boccazzi, Paolo

    2010-10-01

    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.

  6. Exposure monitoring and risk assessment of biphenyl in the workplace.

    Science.gov (United States)

    Kim, Hyeon-Yeong; Shin, Sae-Mi; Ham, Miran; Lim, Cheol-Hong; Byeon, Sang-Hoon

    2015-05-13

    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.

  7. 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.

  8. 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...

  9. 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...

  10. Genetic Evidence for the Physiological Significance of the d-Tagatose 6-Phosphate Pathway of Lactose and d-Galactose Degradation in Staphylococcus aureus1

    Science.gov (United States)

    Bissett, Donald L.; Anderson, Richard L.

    1974-01-01

    Mutants of Staphylococcus aureus were isolated which were unable to utilize d-galactose or lactose, but which were able to utilize all other carbohydrates tested. Growth of the mutants on a peptone-containing medium was inhibited by d-galactose. Of those mutants selected for further study, one (tagI2) was missing d-galactose 6-phosphate isomerase, one (tagK3) was missing d-tagatose 6-phosphate kinase, and one (tagA4) was missing d-tagatose 1, 6-diphosphate aldolase. Each of these mutants accumulated the substrate of the missing enzyme intracellularly. Spontaneous revertants of each of the mutants simultaneously regained their ability to utilize d-galactose and lactose, lost their sensitivity to d-galactose, regained the missing enzymatic activities, and no longer accumulated intermediates of the d-tagatose 6-phosphate pathway. These data support our previous contention that the physiologically significant route for the metabolism of d-galactose and the d-galactosyl moiety of lactose in S. aureus is the d-tagatose 6-phosphate pathway. Furthermore, a mutant constitutive for all three enzymes of this pathway was isolated, indicating that the products of the tagI, tagK, and tagA genes are under common genetic control. This conclusion was supported by the demonstration that d-galactose 6-phosphate isomerase, d-tagatose 6-phosphate kinase, and d-tagatose 1, 6-diphosphate aldolase are coordinately induced in the parental strain. PMID:4277494

  11. Epidermal Growth Factor Cytoplasmic Domain Affects ErbB Protein Degradation by the Lysosomal and Ubiquitin-Proteasome Pathway in Human Cancer Cells

    Directory of Open Access Journals (Sweden)

    Aleksandra Glogowska

    2012-05-01

    Full Text Available The cytoplasmic domains of EGF-like ligands, including EGF cytoplasmic domain (EGFcyt, have important biological functions. Using specific constructs and peptides of human EGF cytoplasmic domain, we demonstrate that EGFcyt facilitates lysosomal and proteasomal protein degradation, and this coincided with growth inhibition of human thyroid and glioma carcinoma cells. EGFcyt and exon 22–23-encoded peptide (EGF22.23 enhanced procathepsin B (procathB expression and procathB-mediated lysosomal degradation of EGFR/ErbB1 as determined by inhibitors for procathB and the lysosomal ATPase inhibitor BafA1. Presence of mbEGFctF, EGFcyt, EGF22.23, and exon 23-encoded peptides suppressed the expression of the deubiqitinating enzyme ubiquitin C-terminal hydrolase-L1 (UCH-L1. This coincided with hyperubiquitination of total cellular proteins and ErbB1/2 and reduced proteasome activity. Upon small interfering RNA-mediated silencing of endogenously expressed UCH-L1, a similar hyperubiquitinylation phenotype, reduced ErbB1/2 content, and attenuated growth was observed. The exon 23-encoded peptide region of EGFcyt was important for these biologic actions. Structural homology modeling of human EGFcyt showed that this molecular region formed an exposed surface loop. Peptides derived from this EGFcyt loop structure may aid in the design of novel peptide therapeutics aimed at inhibiting growth of cancer cells.

  12. Analysis of the Durability of PEM FC Membrane Electrode Assemblies in Automotive Applications through the Fundamental Understanding of Membrane and MEA Degradation Pathways

    Energy Technology Data Exchange (ETDEWEB)

    Perry, Randal L. [DuPont

    2013-10-31

    The Project focused on mitigation of degradation processes on membrane electrode assemblies. The approach was to develop a model to improve understanding of the mechanisms, and to use it to focus mitigation strategies. The detailed effects of various accelerated stress tests (ASTs) were evaluated to determine the best subset to use in model development. A combination of ASTs developed by the Fuel Cell Commercialization Conference of Japan and the Fuel Cell Tech Team were selected for use. The ASTs were compared by measuring effects on performance, running in-situ diagnostics, and performing microscopic analyses of the membrane electrode assemblies after the stress tests were complete. Nissan ran FCCJ AST protocols and performed in situ and ex-situ electrochemical testing. DuPont ran FCTT and USFCC AST protocols, performed scanning and transmission electron microscopy and ran in-situ electrochemical tests. Other ex-situ testing was performed by IIT, along with much of the data analysis and model development. These tests were then modified to generate time-dependent data of the degradation mechanisms. Three different catalyst types and four membrane variants were then used to generate data for a theoretically-based degradation model. An important part of the approach was to use commercially available materials in the electrodes and membranes made in scalable semiworks processes rather than lab-based materials. This constraint ensured all materials would be practicable for full-scale testing. The initial model for the electrode layer was tested for internal consistency and agreement with the data. A Java-based computer application was developed to analyze the time-dependent AST data using polarization curves with four different cathode gas feeds and generate model parameters. Data showed very good reproducibility and good consistency as cathode catalyst loadings were varied. At the point of termination of the project, a basic electrode model was in hand with several

  13. Electron ionization mass spectral fragmentation study of sulfation derivatives of polychlorinated biphenyls

    Directory of Open Access Journals (Sweden)

    Robertson Larry W

    2009-03-01

    Full Text Available Abstract Background Polychlorinated biphenyls are persistent organic pollutants that can be metabolized via hydroxylated PCBs to PCB sulfate metabolites. The sensitive and selective analysis of PCB sulfate monoesters by gas chromatography-mass spectrometry (GC-MS requires their derivatization, for example, as PCB 2,2,2-trichloroethyl (TCE sulfate monoesters. To aid in the identification of unknown PCB sulfate metabolites isolated from biological samples, the electron impact MS fragmentation pathways of selected PCB TCE sulfate diesters were analyzed and compared to the fragmentation pathways of the corresponding methoxylated PCBs. Results The most abundant and characteristic fragment ions of PCB TCE sulfate diesters were formed by releasing CHCCl3, SO3, HCl2 and/or CCl3 from the TCE sulfate moiety and Cl2, HCl, ethyne and chloroethyne from an intermediate phenylcyclopentadienyl cation. The fragmentation pattern depended on the degree of chlorination and the position of the TCE sulfate moiety (i.e., ortho vs. meta/para to the second phenyl ring, but were independent of the chlorine substitution pattern. These fragmentation pathways are similar to the fragmentation pathways of structurally related methoxylated PCBs. Conclusion Knowledge of the fragmentation patterns of PCB TCE sulfate diesters will greatly aid in determining the position of sulfate moiety (ortho vs. meta/para of unknown PCB sulfate metabolites isolated from environmental or laboratory samples.

  14. Biodegradation of polychlorinated biphenyls (PCBs by the novel identified cyanobacterium Anabaena PD-1.

    Directory of Open Access Journals (Sweden)

    Hangjun Zhang

    Full Text Available Polychlorinated biphenyls (PCBs, a class of hazardous pollutants, are difficult to dissipate in the natural environment. In this study, a cyanobacterial strain Anabaena PD-1 showed good resistance against PCB congeners. Compared to a control group, chlorophyll a content decreased 3.7% and 11.7% when Anabaena PD-1 was exposed to 2 and 5 mg/L PCBs for 7 d. This cyanobacterial strain was capable of decomposing PCB congeners which was conclusively proved by determination of chloride ion concentrations in chlorine-free medium. After 7 d, the chloride ion concentrations in PCB-treated groups (1, 2, 5 mg/L were 3.55, 3.05, and 2.25 mg/L, respectively. The genetic information of strain PD-1 was obtained through 16S rRNA sequencing analysis. The GenBank accession number of 16S rRNA of Anabaena PD-1 was KF201693.1. Phylogenetic tree analysis clearly indicated that Anabaena PD-1 belonged to the genus Anabaena. The degradation half-life of Aroclor 1254 by Anabaena PD-1 was 11.36 d; the total degradation rate for Aroclor 1254 was 84.4% after 25 d. Less chlorinated PCB congeners were more likely to be degraded by Anabaena PD-1 in comparison with highly chlorinated congeners. Meta- and para-chlorines in trichlorodiphenyls and tetrachlorobiphenyls were more susceptible to dechlorination than ortho-chlorines during the PCB-degradation process by Anabaena PD-1. Furthermore, Anabaena PD-1 can decompose dioxin-like PCBs. The percent biodegradation of 12 dioxin-like PCBs by strain PD-1 ranged from 37.4% to 68.4% after 25 days. Results above demonstrate that Anabaena PD-1 is a PCB-degrader with great potential for the in situ bioremediation of PCB-contaminated paddy soils.

  15. Attenuation of polychlorinated biphenyl sorption to charcoal by humic acids

    NARCIS (Netherlands)

    Koelmans, A.A.; Meulman, B.; Meijer, T.; Jonker, M.T.O.

    2009-01-01

    Strong sorption to black carbon may limit the environmental risks of organic pollutants, but interactions with cosorbing humic acid (HA) may interfere. We studied the attenuative effect of HA additions on the sorption of polychlorinated biphenyls (PCBs) to a charcoal. "Intrinsic" sorption to

  16. Polychlorinated biphenyl in fish samples from Lagos Lagoon, Nigeria

    African Journals Online (AJOL)

    STORAGESEVER

    2009-06-17

    Jun 17, 2009 ... Several fish samples from the Lagos lagoon, Nigeria were analyzed for the presence of polychlorinated biphenyls (PCBs). The fish species analyzed include Tilapia zilli (red belly Tilapia), Ethmalosa fimbriata. (Bonga shad) and Chrysichthys nigrodigitatus (catfish). Eight PCB congeners were identified and.

  17. Modeling polychlorinated biphenyl sorption isotherms for soot and coal

    NARCIS (Netherlands)

    Jantunen, A.P.K.; Koelmans, A.A.; Jonker, M.T.O.

    2010-01-01

    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

  18. 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...

  19. Perinatal exposure to polychlorinated biphenyls and dioxins through dietary intake

    NARCIS (Netherlands)

    M. Huisman (Martijn); S.E.J. Eerenstein (S. E J); C. Koopman-Esseboom (Corine); M. Brouwer (Marije); V. Fidler (Vaclav); F.A.J. Muskiet (Frits); P.J.J. Sauer (Pieter); H. Boersma (Eric)

    1995-01-01

    textabstractPolychlorinated biphenyls (PCBs) and dioxins (polychlorinated dibenzo p-dioxins and dibenzofurans) are potentially hazardous compounds. Since food is the major source (>90%) for the accumulation of PCBs and dioxins in the human body, food habits in women determine the degree of fetal

  20. Polychlorinated biphenyl accumulation and hepatic EROD activity in ...

    African Journals Online (AJOL)

    Polychlorinated biphenyl accumulation and hepatic EROD activity in golden grey mullet Liza aurata from Tunis Bay, southern Mediterranean. ... Liza aurata was used as a bioindicator species to monitor contamination by organic xenobiotics of estuarine water at the outlet of Khélij channel [canal], Tunisia, from November ...

  1. Attenuation of polychlorinated biphenyl sorption to charcoal by humic acids.

    NARCIS (Netherlands)

    Koelmans, A.A.; Meulman, B.; Meijer, T.; Jonker, M.T.O.

    2009-01-01

    Strong sorption to black carbon may limit the environmental risks of organic pollutants, but interactions with cosorbing humic acid (HA) may interfere. We studied the attenuative effect of HA additions on the sorption of polychlorinated biphenyls (PCBs) to a charcoal. "Intrinsic" sorption to

  2. Levels of Lambda-Cyhalothrin and polychlorinated biphenyls ...

    African Journals Online (AJOL)

    The study determined the presence and concentration of chloride, phosphate, lambda-cyhalothrin and polychlorinated biphenyls PCBs by Gas Chromatography-Mass Spectrometry method to discern contamination of selected herbal remedies. Sampling was carefully carried out in Northwest Nigeria. The chloride and the ...

  3. Polychlorinated biphenyl in fish samples from Lagos Lagoon, Nigeria

    African Journals Online (AJOL)

    Several fish samples from the Lagos lagoon, Nigeria were analyzed for the presence of polychlorinated biphenyls (PCBs). The fish species analyzed include Tilapia zilli (red belly Tilapia), Ethmalosa fimbriata (Bonga shad) and Chrysichthys nigrodigitatus (catfish). Eight PCB congeners were identified and quantified in ...

  4. 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

  5. Congener profiles of polychlorinated biphenyls and the effect on ...

    African Journals Online (AJOL)

    This study investigated the effect of freshwater as a point source of PCBs contributing to a marine outfall region. Inflowing and outflowing water from the North End Lake, Port Elizabeth, was collected to determine the contamination levels of polychlorinated biphenyls (PCBs). Mussels at the outflow to the sea were also ...

  6. Transgenic plants to improve rhizoremediation of polychlorinated biphenyls (PCBs)

    Czech Academy of Sciences Publication Activity Database

    Sylvestre, M.; Macek, Tomáš; Macková, Martina

    2009-01-01

    Roč. 20, č. 2 (2009), s. 242-247 ISSN 0958-1669 R&D Projects: GA MŠk 1M06030 Institutional research plan: CEZ:AV0Z40550506 Keywords : bacterial dioxygenases * GM- plants * polychlorinated biphenyls * rhizoremediation Subject RIV: EI - Biotechnology ; Bionics Impact factor: 7.820, year: 2009

  7. Rho iso-alpha acids from hops inhibit the GSK-3/NF-κB pathway and reduce inflammatory markers associated with bone and cartilage degradation

    Directory of Open Access Journals (Sweden)

    Bland Jeffrey S

    2009-08-01

    Full Text Available Abstract Background Rho iso-alpha acids (RIAA from hops have been shown to have anti-inflammatory properties. To understand the mechanisms, we evaluated the effect of RIAA in cell signaling pathways and inflammatory markers using various in vitro models. We also investigated their therapeutic effect in mice with collagen-induced arthritis. Methods The LPS-stimulated RAW 264.7 macrophages were used to evaluate the effect of RIAA on the NF-κB and MAPK signaling pathways; phosphorylation of ERK1/2, p38 and JNK was assessed by western blotting and NF-κB binding by electrophoretic mobility shift assays. Effect on the NF-κB activity was evaluated by the luciferase reporter assays in LPS-stimulated RAW 264.7 cells. GSK-3α/β kinase activity was measured in cell-free assays. The inhibitory effect of RIAA on inflammatory markers was assessed by measuring nitric oxide in LPS-stimulated RAW 264.7 cells, RANKL-mediated TRAP activity in transformed osteoclasts, and TNF-α/IL-1β-mediated MMP-13 expression in SW1353 cells. Mice with collagen-induced arthritis were fed with RIAA for 2 weeks. Symptoms of joint swelling, arthritic index and joint damage were assessed. Results RIAA selectively inhibited the NF-κB pathway while having no effect on ERK1/2, p38 and JNK phosphorylation in LPS-stimulated RAW 264.7 cells. RIAA also inhibited GSK-3α/β kinase activity and GSK-3β dependent phosphorylation of β-catenin in RAW 264.7 cells. In addition, RIAA inhibited NF-κB-mediated inflammatory markers in various cell models, including nitric oxide in LPS-stimulated RAW 264.7 cells, RANKL-mediated TRAP activity in transformed osteoclasts, and TNF-α/IL-1β-mediated MMP-13 expression in SW1353 human chondrosarcoma cells. Finally, in a mouse model of collagen-induced arthritis, RIAA ameliorated joint damage as evidenced by significant reduction of the arthritis index and histology score; at 250 mg/kg-body weight, RIAA had efficacy similar to that of 20 mg

  8. Cucurbita spp. and Cucumis sativus enhance the dissipation of polychlorinated biphenyl congeners by stimulating soil microbial community development

    International Nuclear Information System (INIS)

    Qin, Hua; Brookes, Philip C.; Xu, Jianming

    2014-01-01

    A number of Cucurbita species have the potential to extract polychlorinated biphenyls (PCBs) from soil, but their impact on the soil microbial communities responsible for PCB degradation remains unclear. A greenhouse experiment was conducted to investigate the effect of three Cucurbita and one Cucumis species on PCB dissipation and soil microbial community structure. Compared to the unplanted control, enhanced losses of PCBs (19.5%–42.7%) were observed in all planted soils. Cucurbita pepo and Cucurbita moschata treatments were more efficient in PCB dissipation, and have similar patterns of soil phospholipid fatty acids (PLFAs) and PCB congener profiles. Cucurbita treatments tend to have higher soil microbial biomass than Cucumis. Gram-negative (G − ) bacteria were significantly correlated with PCB degradation rates (R 2 = 0.719, p − bacteria were correlated with dissipation of the penta homologue group (R 2 = 0.590, p − bacteria contributed significantly to soil PCB dissipation. • Fungi have a great potential in the dissipation of high chlorinated biphenyls. -- Cucurbita associated fungi and G − bacteria have important influence on soil PCB dissipation rate and congener profile

  9. Congenital cataract causing mutants of αA-crystallin/sHSP form aggregates and aggresomes degraded through ubiquitin-proteasome pathway.

    Directory of Open Access Journals (Sweden)

    Ilangovan Raju

    Full Text Available BACKGROUND: Mutations of human αA-crystallin cause congenital cataract by protein aggregation. How mutations of αA-crystallin cause disease pathogenesis through protein aggregation is not well understood. To better understand the cellular events leading to protein aggregation, we transfected cataract causing mutants, R12C, R21L, R21W, R49C, R54C, R116C and R116H, of human αA-crystallin in HeLa cells and examined the formation of intracellular protein aggregates and aggresomes by confocal microscopy. METHODOLOGY/PRINCIPAL FINDINGS: YFP-tagged human αA-wild-type (αA-wt was sub-cloned and the mutants were generated by site-directed mutagenesis. The αA-wt and the mutants were individually transfected or co-transfected with CFP-tagged αA-wt or αB-wild-type (αB-wt in HeLa cells. Overexpression of these mutants forms multiple small dispersed cytoplasmic aggregates as well as aggresomes. Co-expression of αB-wt with these mutants significantly inhibited protein aggregates where as co-expression with αA-wt enhanced protein aggregates which seems to be due to co-aggregation of the mutants with αA-wt. Aggresomes were validated by double immunofluorescence by co-localization of γ-tubulin, a centrosome marker protein with αA-crystallin. Furthermore, increased ubiquitination was detected in R21W, R116C and R116H as assessed by western blot analyses. Immunostaining with an ubiquitin antibody revealed that ubiquitin inclusions in the perinuclear regions were evident only in R116C transfected cells. Pulse chase assay, after cycloheximide treatment, suggested that R116C degraded faster than the wild-type control. CONCLUSIONS/SIGNIFICANCE: Mutants of αA-crystallin form aggregates and aggresomes. Co-expression of αA-wt with the mutants increased aggregates and co-expression of αB-wt with the mutants significantly decreased the aggregates. The mutant, R116C protein degraded faster than wild-type control and increased ubiquitination was evident in R

  10. Photodegradation of lambda-cyhalothrin and cypermethrin in aqueous solution as affected by humic acid and/or copper: intermediates and degradation pathways.

    Science.gov (United States)

    Xie, Jimin; Wang, Pingli; Liu, Jun; Lv, Xiaomeng; Jiang, Deli; Sun, Cheng

    2011-11-01

    The influence of coexisting humic acids (HA) or Cu²⁺ on the photodegradation of pesticides lambda-cyhalothrin (λ-CHT) and cypermethrin (CPM) in aqueous solution was studied under xenon lamp irradiation. The removal efficiency of pesticides λ-CHT and CPM were enhanced in the presence of either Cu²⁺ or HA but restrained in the presence of both Cu²⁺ and HA. The photodegradation of λ-CHT and CPM followed first-order reaction kinetics. The photodegradation intermediates of λ-CHT and CPM were determined using gas chromatography/mass spectrometry. Possible photodegradation pathways included decarboxylation, ester bond cleavage, dechlorination, and phenyl group removal. Copyright © 2011 SETAC.

  11. Molecular Characterization of 2-Chlorobiphenyl Degrading Stenotrophomonas maltophilia GS-103

    Digital Repository Service at National Institute of Oceanography (India)

    Somaraja, P.K.; Gayathri, D.; Ramaiah, N.

    York 2013 Abstract The catabolic potential of transformer oil con- taminated soil bacteria in aerobic degradation of poly- chlorinated biphenyls (PCB) were assessed. Transformer oil contaminated soil sample was subjected to microcosm enrichment..., high insulation property, high fat solubility and low volatility, PCB have been used for several decades in a wide range of industrial applications such as oil in transformers, Con- ductor of heat, dielectrics in capacitors, solvents for paints...

  12. Cucurbita spp. and Cucumis sativus enhance the dissipation of polychlorinated biphenyl congeners by stimulating soil microbial community development.

    Science.gov (United States)

    Qin, Hua; Brookes, Philip C; Xu, Jianming

    2014-01-01

    A number of Cucurbita species have the potential to extract polychlorinated biphenyls (PCBs) from soil, but their impact on the soil microbial communities responsible for PCB degradation remains unclear. A greenhouse experiment was conducted to investigate the effect of three Cucurbita and one Cucumis species on PCB dissipation and soil microbial community structure. Compared to the unplanted control, enhanced losses of PCBs (19.5%-42.7%) were observed in all planted soils. Cucurbita pepo and Cucurbita moschata treatments were more efficient in PCB dissipation, and have similar patterns of soil phospholipid fatty acids (PLFAs) and PCB congener profiles. Cucurbita treatments tend to have higher soil microbial biomass than Cucumis. Gram-negative (G(-)) bacteria were significantly correlated with PCB degradation rates (R(2) = 0.719, p Cucurbita related soil microorganisms could play an important role in remediation of PCB contaminated soils. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Degradation of thiram in soil

    International Nuclear Information System (INIS)

    Raghu, K.; Murthy, N.B.K.; Kumarsamy, R.

    1975-01-01

    Determination of the residual 35 S labelled tetramethylthiuram disulfide showed that the fungicide persisted longer in sterilized than in unsterilized soil, while the chloroform extractable radioactivity decreased, the water extractable radioactivity increased with increase in time. However, in sterilized soil the water extractable radioactivity remained more or less constant. Degradation of the fungicide was further demonstrated by the release of C 35 S 2 from soil treated with labelled thiram. Dimethylamine was found to be one of the degradation products. A bacterium isolated from thiram-enriched soil could degrade the fungicide in shake culture. The degradation pathways of thiram in sterilized and unsterilized soils are discussed. (author)

  14. 3-Sulphocatechol 2,3-dioxygenase and other dioxygenases (EC 1.13.11.2 and EC 1.14.12.-) in the degradative pathways of 2-aminobenzenesulphonic, benzenesulphonic and 4-toluenesulphonic acids in Alcaligenes sp. strain O-1.

    Science.gov (United States)

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

    1994-07-01

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

  15. Variability of Biological Degradation of Aromatic Hydrocarbons in an Aerobic Aquifer Determined by Laboratory Batch Experiments

    DEFF Research Database (Denmark)

    Nielsen, Per Henning; Christensen, Thomas Højlund

    1994-01-01

    The biological aerobic degradation of 7 aromatic hydrocarbons (benzene, toluene, o-xylene, p-dichlorobenzene, o-dichlorobenzene, naphthalene and biphenyl) was studied for 149 days in replicate laboratory batch experiments with groundwater and sediment from 8 localities representing a 15 m × 30 m...

  16. Method and means for filtering polychlorinated biphenyls from a gas stream

    International Nuclear Information System (INIS)

    Sowinski, R.F.

    1992-01-01

    This patent describes a method of filtering, adjacent to an end user-customer's residence or business in which at least a single gas appliance is located, a natural gas stream in which polychlorinated biphenyls (PCB's) and degraded PCB products have been concentrated at sufficient levels to be a health threat in a natural gas gathering and distributing network. It comprises: introducing the natural gas stream to a filter selected from a group that includes impingement, absorbing and adsorbing media whereby PCB's and degraded PCB products concentrated in the gas stream at sufficient levels to be a health threat by a periodic loading of the natural gas within the gathering and distributing network, are filtered from the gas stream and captured irrespective of mode of transport, passing the filtered natural gas stream to the customer's gas appliance wherein safe use of the energy associated with the stream occurs; periodically and safely removing the filter, inserting a new filter in place of the removed filter

  17. Anaerobic benzene degradation by bacteria.

    Science.gov (United States)

    Vogt, Carsten; Kleinsteuber, Sabine; Richnow, Hans-Hermann

    2011-11-01

    Benzene is a widespread and toxic contaminant. The fate of benzene in contaminated aquifers seems to be primarily controlled by the abundance of oxygen: benzene is aerobically degraded at high rates by ubiquitous microorganisms, and the oxygen-dependent pathways for its breakdown were elucidated more than 50 years ago. In contrast, benzene was thought to be persistent under anoxic conditions until 25 years ago. Nevertheless, within the last 15 years, several benzene-degrading cultures have been enriched under varying electron acceptor conditions in laboratories around the world, and organisms involved in anaerobic benzene degradation have been identified, indicating that anaerobic benzene degradation is a relevant environmental process. However, only a few benzene degraders have been isolated in pure culture so far, and they all use nitrate as an electron acceptor. In some highly enriched strictly anaerobic cultures, benzene has been described to be mineralized cooperatively by two or more different organisms. Despite great efforts, the biochemical mechanism by which the aromatic ring of benzene is activated in the absence of oxygen is still not fully elucidated; methylation, hydroxylation and carboxylation are discussed as likely reactions. This review summarizes the current knowledge about the 'key players' of anaerobic benzene degradation under different electron acceptor conditions and the possible pathway(s) of anaerobic benzene degradation. © 2011 The Authors; Journal compilation © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

  18. Anaerobic benzene degradation by bacteria

    Science.gov (United States)

    Vogt, Carsten; Kleinsteuber, Sabine; Richnow, Hans‐Hermann

    2011-01-01

    Summary Benzene is a widespread and toxic contaminant. The fate of benzene in contaminated aquifers seems to be primarily controlled by the abundance of oxygen: benzene is aerobically degraded at high rates by ubiquitous microorganisms, and the oxygen‐dependent pathways for its breakdown were elucidated more than 50 years ago. In contrast, benzene was thought to be persistent under anoxic conditions until 25 years ago. Nevertheless, within the last 15 years, several benzene‐degrading cultures have been enriched under varying electron acceptor conditions in laboratories around the world, and organisms involved in anaerobic benzene degradation have been identified, indicating that anaerobic benzene degradation is a relevant environmental process. However, only a few benzene degraders have been isolated in pure culture so far, and they all use nitrate as an electron acceptor. In some highly enriched strictly anaerobic cultures, benzene has been described to be mineralized cooperatively by two or more different organisms. Despite great efforts, the biochemical mechanism by which the aromatic ring of benzene is activated in the absence of oxygen is still not fully elucidated; methylation, hydroxylation and carboxylation are discussed as likely reactions. This review summarizes the current knowledge about the ‘key players’ of anaerobic benzene degradation under different electron acceptor conditions and the possible pathway(s) of anaerobic benzene degradation. PMID:21450012

  19. IRIS Toxicological Review of Biphenyl (External Review Draft) ...

    Science.gov (United States)

    EPA is conducting a peer review of the scientific basis supporting the human health hazard and dose-response assessment of biphenyl that will appear in the Integrated Risk Information System (IRIS) database. EPA is undertaking a new health assessment for biphenyl for the Integrated Risk Information System (IRIS). The outcome of this project will be a Toxicological Review and IRIS and IRIS Summary of biohenyl that will be entered on the IRIS database. IRIS is an EPA database containing Agency scientific positions on potential adverse human health effects that may result from chronic (or lifetime) exposure to chemicals in the environment. IRIS contains chemical-specific summaries of qualitative and quantitative health information to evaluate potential public health risks associated with exposure assessment information to evaluate potential public health risks associated with environmental contaminants. The IRIS database is relied on for the development of risk assessments sites-specific environmental decisions, and rule making.

  20. Hydroxylated biphenyls as tyrosinase inhibitor: A spectrophotometric and electrochemical study.

    Science.gov (United States)

    Ruzza, Paolo; Serra, Pier Andrea; Fabbri, Davide; Dettori, Maria Antonietta; Rocchitta, Gaia; Delogu, Giovanna

    2017-01-27

    A small collection of C 2 -symmetry hydroxylated biphenyls was prepared by straightforward methods and the capability to act as inhibitors of tyrosinase has been evaluated by both spectrophotometric and electrochemical assays. Our attention was focused on the diphenolase activity of this enzyme characterized by the absence of the characteristic lag time of enzymatic reaction of its monophenolase activity. To this purpose, we evaluated the capability of tyrosinase to oxidize a natural o-diphenol substrate to o-quinone analyzing the changes in the UV-Vis spectrum of a solution of caffeic acid and the reduction of the cathodic current in a tyrosinase-biosensor, respectively. Results of both the methods were comparable. Most of the compounds possessed higher inhibitory activity compared to compound 1, a known hydroxylated biphenyl inhibitor of tyrosinase. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  1. IGF-1 and PDGF-bb Suppress IL-1β-Induced Cartilage Degradation through Down-Regulation of NF-κB Signaling: Involvement of Src/PI-3K/AKT Pathway

    Science.gov (United States)

    Mobasheri, Ali; Buhrmann, Constanze; Aldinger, Constance; Rad, Jafar Soleimani; Shakibaei, Mehdi

    2011-01-01

    Objective Interleukin-1β (IL-1β) is a pro-inflammatory cytokine that plays a key role in the pathogenesis of osteoarthritis (OA). Growth factors (GFs) capable of antagonizing the catabolic actions of cytokines may have therapeutic potential in the treatment of OA. Herein, we investigated the potential synergistic effects of insulin-like growth factor (IGF-1) and platelet-derived growth factor (PDGF-bb) on different mechanisms participating in IL-1β-induced activation of nuclear transcription factor-κB (NF-κB) and apoptosis in chondrocytes. Methods Primary chondrocytes were treated with IL-1β to induce dedifferentiation and co-treated with either IGF-1 or/and PDGF-bb and evaluated by immunoblotting and electron microscopy. Results Pretreatment of chondrocytes with IGF-1 or/and PDGF-bb suppressed IL-1β-induced NF-κB activation via inhibition of IκB-α kinase. Inhibition of IκB-α kinase by GFs led to the suppression of IκB-α phosphorylation and degradation, p65 nuclear translocation and NF-κB-regulated gene products involved in inflammation and cartilage degradation (COX-2, MMPs) and apoptosis (caspase-3). GFs or BMS-345541 (specific inhibitor of the IKK) reversed the IL-1β-induced down-regulation of collagen type II, cartilage specific proteoglycans, β1-integrin, Shc, activated MAPKinase, Sox-9 and up-regulation of active caspase-3. Furthermore, the inhibitory effects of IGF-1 or/and PDGF-bb on IL-1β-induced NF-κB activation were sensitive to inhibitors of Src (PP1), PI-3K (wortmannin) and Akt (SH-5), suggesting that the pathway consisting of non-receptor tyrosine kinase (Src), phosphatidylinositol 3-kinase and protein kinase B must be involved in IL-1β signaling. Conclusion The results presented suggest that IGF-1 and PDGF-bb are potent inhibitors of IL-1β-mediated activation of NF-κB and apoptosis in chondrocytes, may be mediated in part through suppression of Src/PI-3K/AKT pathway, which may contribute to their anti-inflammatory effects. PMID

  2. 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.

  3. Microbial degradation of herbicides.

    Science.gov (United States)

    Singh, Baljinder; Singh, Kashmir

    2016-01-01

    Herbicides remain the most effective, efficient and economical way to control weeds; and its market continues to grow even with the plethora of generic products. With the development of herbicide-tolerant crops, use of herbicides is increasing around the world that has resulted in severe contamination of the environment. The strategies are now being developed to clean these substances in an economical and eco-friendly manner. In this review, an attempt has been made to pool all the available literature on the biodegradation of key herbicides, clodinafop propargyl, 2,4-dichlorophenoxyacetic acid, atrazine, metolachlor, diuron, glyphosate, imazapyr, pendimethalin and paraquat under the following objectives: (1) to highlight the general characteristic and mode of action, (2) to enlist toxicity in animals, (3) to pool microorganisms capable of degrading herbicides, (4) to discuss the assessment of herbicides degradation by efficient microbes, (5) to highlight biodegradation pathways, (6) to discuss the molecular basis of degradation, (7) to enlist the products of herbicides under degradation process, (8) to highlight the factors effecting biodegradation of herbicides and (9) to discuss the future aspects of herbicides degradation. This review may be useful in developing safer and economic microbiological methods for cleanup of soil and water contaminated with such compounds.

  4. Degradation of triphenylborane-pyridine antifouling agent in water by copper ions.

    Science.gov (United States)

    Tsuboi, Ai; Okamura, Hideo; Kaewchuay, Netnapit; Fukushi, Keiichi; Zhou, Xiaojian; Nishida, Tomoaki

    2013-01-01

    Triphenylborane-pyridine (TPBP) is an antifouling compound used in Asian countries, including Japan, and its residue has not been detected in aquatic environments to date. There are limited data on its fate for environmental management. The purpose of this study was to evaluate whether TPBP is degraded by metal ions in aquatic environments. TPBP with metal ions in 20 mM sodium acetate buffer at pH 8.0 was placed at 25 degrees C in the dark for 24 h. The concentrations of TPBP and its degradation products, such as diphenylboronic acid, phenylboronic acid (MPB), phenol, benzene, biphenyl, and boron were determined. The presence of copper ions (50 mg/l), but not zinc or manganese ions, resulted in complete degradation of TPBP in 24 h. The TPBP degradation was much faster than the boron production in the initial reaction (0-1 h) with copper salts, depending on the copper salts tested. TPBP was degraded by copper ions (5 mg/l) in 24 h, producing phenol, MPB, biphenyl, and borate. Cu2+ as copper(II) chloride or copper(II) acetate led to complete degradation of TPBP, and thylenediaminetetraacetic acid disodium salt addition suppressed the TPBP degradation. Cu+ as copper(I) acetate also completely degraded TPBP, and bathocuproine addition suppressed the TPBP degradation. This suggests that copper ions existing in natural environments might degrade TPBP released from antifouling paint into water, and this could be one of the important mechanisms to dissipate TPBP residues in aquatic environments.

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

    Science.gov (United States)

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

    2016-01-01

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

  6. Use of liquid chromatography/electrospray ionization tandem mass spectrometry to study the degradation pathways of terbuthylazine (TER) by Typha latifolia in constructed wetlands: identification of a new TER metabolite.

    Science.gov (United States)

    Gikas, Evagelos; Papadopoulos, Nikolaos G; Bazoti, Fotini N; Zalidis, Georgios; Tsarbopoulos, Anthony

    2012-01-30

    S-Triazines are used worldwide as herbicides for agricultural and non-agricultural purposes. Although terbuthylazine (TER) is the second most frequently used S-triazine, there is limited information on its metabolism. For this reason, an analytical method based on liquid chromatography/electrospray ionization tandem mass spectrometry (LC-ESI MS/MS) has been developed aiming at the identification of TER and its five major metabolites (desisopropyl-hydroxy-atrazine, desethyl-hydroxy-terbuthylazine, desisopropyl-atrazine, hydroxy-terbuthylazine and desethyl-terbuthylazine) in constructed wetland water samples. The separation of TER and its major metabolites was performed by reversed-phase high-performance liquid chromatography (HPLC) on a C(8) column using a gradient elution of aqueous acetic acid 1% (solvent A) and acetonitrile (solvent B), followed by MS/MS analysis on a triple quadrupole mass spectrometer. The data-depended analysis (DDA) scan approach has been employed and the main degradation pathways of both hydroxyl and chloro (dealkylated and alkylated) metabolites are elucidated through the tandem mass spectral (MS/MS) interpretation of triazine fragments under CID conditions. In addition, another major metabolite of TER, namely N2-tert-butyl-N4-ethyl-6-methoxy-1,3,5-triazine-2,4-diamine, has been identified. This methodology can be further employed in biodegradation studies of TER, thus assisting the assessment of its environmental impact. Copyright © 2011 John Wiley & Sons, Ltd.

  7. Anaerobic benzene degradation by bacteria

    OpenAIRE

    Vogt, Carsten; Kleinsteuber, Sabine; Richnow, Hans‐Hermann

    2011-01-01

    Summary Benzene is a widespread and toxic contaminant. The fate of benzene in contaminated aquifers seems to be primarily controlled by the abundance of oxygen: benzene is aerobically degraded at high rates by ubiquitous microorganisms, and the oxygen‐dependent pathways for its breakdown were elucidated more than 50 years ago. In contrast, benzene was thought to be persistent under anoxic conditions until 25 years ago. Nevertheless, within the last 15 years, several benzene‐degrading cultures...

  8. Temporal and spatial variation of polychlorinated biphenyls (PCBs) contamination in environmental compartments of highly polluted area in Central Russia.

    Science.gov (United States)

    Malina, Natalia; Mazlova, Elena A

    2017-10-01

    This study highlights the fact that serious contamination from polychlorinated biphenyls (PCBs) still exists in Serpukhov City (Russia). The research help to determine the temporal (16- and 24-year periods) and spatial PCBs distribution in the environmental compartments of the studied region. Samples of soil, sediments, water and plants were analysed in order to establish their contamination levels. The most recent data on the Serpukhov City's soil contamination showed that the PCBs concentrations varies from 0.0009 to 1169 mg/kg depending on the sampling point and the distance from the pollution source. The temporal trends of the contamination distribution with the soil depth showed contamination migration in the upper soil layers of the highly polluted site. The high level of water pollution (11.5 μg/L) in the proximity to the contamination source and the sediments contamination (0.098-119 mg/kg) were determined, as well as the water migration pathways of the PCBs that were prevalent in the studied region. The PCB congener group (by the level of chlorination) analysis showed that heptachlorinated biphenyls were only found in the soils in close proximity to the contamination place, while biphenyls with Cl ≤ 6 were found in the soil samples downstream of the condenser plant and with Cl ≤ 5 in the soil samples upstream of the plant. The plant uptake of PCBs, even on the extremely contaminated site, was shown. In turn, this research present new knowledge necessary for the development of a contaminated territory remediation strategy. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Inhibition of LPS-induced splenocyte proliferation by ortho-substituted polychlorinated biphenyl congeners

    International Nuclear Information System (INIS)

    Smithwick, L. Ashley; Smith, Andrew; Quensen, John F.; Stack, Allison; London, Lucille; Morris, Pamela J.

    2003-01-01

    Polychlorinated biphenyls (PCBs) are persistent environmental contaminants, and their ubiquitous nature has prompted studies of their potential health hazards. As a result of their lipophilic nature, PCBs accumulate in breast milk and subsequently affect the health of offspring of exposed individuals. Biological effects of PCBs in animals have mostly been attributed to coplanar congeners, although effects of ortho congeners also have been demonstrated. To investigate the relationship of immunotoxicity and chlorine substitution pattern, the effects of PCB congeners and mixtures of ortho and non-ortho-substituted constituents of Aroclor 1242 on splenocytes from C57B1/6 mice were examined. The immunotoxic endpoints investigated included splenocyte viability, lipopolysaccharide (LPS)-induced splenocyte proliferation, and LPS-induced antibody secretion. Congeners with multiple ortho chlorines preferentially inhibited splenocyte proliferation as compared with non- or mono-ortho-substituted congeners. However, mixtures of non- and mono-ortho-substituted congeners and multi-ortho-substituted congeners inhibited LPS-induced splenocyte proliferation and antibody secretion at similar concentrations. Exposure of splenocytes to these mixtures did not activate the aryl hydrocarbon receptor (AhR) signal transduction pathway. These results suggest individual multi-ortho-substituted congeners preferentially inhibit LPS-induced splenocyte proliferation, while congeners not exhibiting an effect individually may have additive effects in a mixture to produce an immunotoxic response through an AhR-independent pathway

  10. Isolation and characterization of different plant associated bacteria and their potential to degrade polychlorinated biphenyls

    Czech Academy of Sciences Publication Activity Database

    Ionescu, M.; Beranová, K.; Dudková, V.; Kochánková, L.; Demnerová, K.; Macek, Tomáš; Macková, M.

    2009-01-01

    Roč. 63, č. 6 (2009), s. 667-672 ISSN 0964-8305 Grant - others:GA ČR(CZ) GA525/09/1058; GA MŠk(CZ) ME09024; GA MŠk(CZ) 2B06156 Program:GA; 2B Institutional research plan: CEZ:AV0Z40550506 Keywords : phytoremediation * PCB * rhizoremediation Subject RIV: EI - Biotechnology ; Bionics Impact factor: 2.252, year: 2009

  11. Ortho-substituent correlated retention of polychlorinated biphenyls on a 50% n-octyl-methylpolysiloxane stationary phase by HRGC/MSD

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, R.; Ballschmiter, K.

    1988-11-01

    Polychlorinated biphenyls (PCB) have been known as ubiquitous environmental pollutants since the late 60s. They are found partitioned between all environmental compartments according to their physico-chemical properties. Investigation of their partitioning, degradation, and transport behaviour demands sensitive and selective analytical methods for this complex mixture of up to 209 theoretically possible compounds. Congener-specific separation by high-resolution gas chromatography coupled with mass-selective detection would be a suitable approach to this multi-compound problem. In this paper, the separation of PCB congeners by capillary gas chromatography (HRGC) on a 50% n-octyl-methylpolysiloxane phase is presented.

  12. Health and productivity of dairy cows fed polychlorinated biphenyls

    Energy Technology Data Exchange (ETDEWEB)

    Willett, L.B.; Liu, T.T.; Durst, H.I.; Smith, K.L.; Redman, D.R.

    1987-07-01

    Holstein cows were studied through a complete lactation, a nonlactating period, and 42 days of a subsequent lactation for overt and subtle responses to a commercial mixture of polychlorinated biphenyls. Dosed cows (n = 4) received consecutive 60-day periods of daily dosing with 10, 100, and 1000 mg of Aroclor 1254. Control cows (n = 6) received daily sham doses. The following were recorded: daily milk production, feed intake, and health observations; weekly body weight, temperature, heart and respiratory rates and rectal palpation; semi-monthly clinical chemistry determinations; and monthly milk fat, microbiological culture of quarter foremilk samples, and composite milk somatic cell counts. Mean daily milk production (22.4 +/- 1.1 vs 24.8 +/- 1.0 kg) and net energy of a complete lactation (1.46 +/- 0.05 vs 1.45 +/- 0.03 Mcal/kg dry matter intake) were not different (p = 0.85) for control and PCB-dosed cows. Milk production during the first 42 days of the subsequent lactation was also similar for control and dosed cows. Occurrences of injuries, dysfunctions, and general infections were not related to polychlorinated biphenyl exposure. Intramammary infections were detected for both lactations with 51 and 32 infections detected in microbiological cultures, respectively, for the control and dosed groups. Environmental pathogens were most frequently isolated from cases of clinically apparent mastitis. The majority of quarter infections detected were due to Corynebacterium bovis. Only one animal (dosed, necropsy revealed left oviduct obstructed) failed to conceive with three to six services required before conception for the other control and dosed cows. Exposure to polychlorinated biphenyls resulting in maximal residues in milk fat, near 100 micrograms/g, had no apparent effect on health and productivity.

  13. Ideal gas thermodynamic properties for the phenyl, phenoxy, and o-biphenyl radicals

    Science.gov (United States)

    Burcat, A.; Zeleznik, F. J.; Mcbride, B. J.

    1985-01-01

    Ideal gas thermodynamic properties of the phenyl and o-biphenyl radicals, their deuterated analogs and the phenoxy radical were calculated to 5000 K using estimated vibrational frequencies and structures. The ideal gas thermodynamic properties of benzene, biphenyl, their deuterated analogs and phenyl were also calculated.

  14. 21 CFR 509.30 - Temporary tolerances for polychlorinated biphenyls (PCB's).

    Science.gov (United States)

    2010-04-01

    ... (PCB's). 509.30 Section 509.30 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND....30 Temporary tolerances for polychlorinated biphenyls (PCB's). (a) Polychlorinated biphenyls (PCB's..., PCB's have become a persistent and ubiquitous contaminant in the environment. As a result, certain...

  15. Cathode degradation

    Energy Technology Data Exchange (ETDEWEB)

    Shores, D.A.; Selman, J.R.; Ong, E.T.

    1989-12-01

    This report describes the results of a three-year study of cathode degradation in molten carbonate fuel cells involving both experimental and theoretical work. A keystone of the study is the development of a mathematical model, which describes cathode degradation in terms of the fundamental processes of a fluxing mechanism, i.e., dissolution, transport and precipitation. New fundamental data have been obtained on the solubility of NiO, especially on the effect of water vapor, and on the kinetics of NiO dissolution in (Li{sub 0.62}K{sub 0.38}){sub 2}CO{sub 3}, and these data have been incorporated in the model. Laboratory cell testing in 3 cm{sup 2} cells has been carried out to obtain experimental data on degradation rates for direct comparison with the calculated results from the model. These comparisons have helped to verify several aspects of the model. For example, the model predicts with fair accuracy the location of the Ni deposit in the tile and the deposition rate. It is also fair to point out that the model is a relatively simple representation of complex processes, and it does not answer all questions about cathode degradation. Further work is needed. Because of its fundamental basis, the model can readily be upgraded and extended when further experimental data become available. The solubility studies, modeling efforts and cell testing have interacted iteratively to optimize progress. 94 figs., 24 tabs.

  16. Metabolic pathway involved in 2-methyl-6-ethylaniline degradation by Sphingobium sp. strain MEA3-1 and cloning of the novel flavin-dependent monooxygenase system meaBA.

    Science.gov (United States)

    Dong, Weiliang; Chen, Qiongzhen; Hou, Ying; Li, Shuhuan; Zhuang, Kai; Huang, Fei; Zhou, Jie; Li, Zhoukun; Wang, Jue; Fu, Lei; Zhang, Zhengguang; Huang, Yan; Wang, Fei; Cui, Zhongli

    2015-12-01

    2-Methyl-6-ethylaniline (MEA) is the main microbial degradation intermediate of the chloroacetanilide herbicides acetochlor and metolachlor. Sphingobium sp. strain MEA3-1 can utilize MEA and various alkyl-substituted aniline and phenol compounds as sole carbon and energy sources for growth. We isolated the mutant strain MEA3-1Mut, which converts MEA only to 2-methyl-6-ethyl-hydroquinone (MEHQ) and 2-methyl-6-ethyl-benzoquinone (MEBQ). MEA may be oxidized by the P450 monooxygenase system to 4-hydroxy-2-methyl-6-ethylaniline (4-OH-MEA), which can be hydrolytically spontaneously deaminated to MEBQ or MEHQ. The MEA microbial metabolic pathway was reconstituted based on the substrate spectra and identification of the intermediate metabolites in both the wild-type and mutant strains. Plasmidome sequencing indicated that both strains harbored 7 plasmids with sizes ranging from 6,108 bp to 287,745 bp. Among the 7 plasmids, 6 were identical, and pMEA02' in strain MEA3-1Mut lost a 37,000-bp fragment compared to pMEA02 in strain MEA3-1. Two-dimensional electrophoresis (2-DE) and protein mass fingerprinting (PMF) showed that MEA3-1Mut lost the two-component flavin-dependent monooxygenase (TC-FDM) MeaBA, which was encoded by a gene in the lost fragment of pMEA02. MeaA shared 22% to 25% amino acid sequence identity with oxygenase components of some TC-FDMs, whereas MeaB showed no sequence identity with the reductase components of those TC-FDMs. Complementation with meaBA in MEA3-1Mut and heterologous expression in Pseudomonas putida strain KT2440 resulted in the production of an active MEHQ monooxygenase. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  17. Combined effect of microwave and activated carbon on the remediation of polychlorinated biphenyl-contaminated soil.

    Science.gov (United States)

    Liu, Xitao; Yu, Gang

    2006-04-01

    The application of microwave and activated carbon for the treatment of polychlorinated biphenyl (PCB) contaminated soil was explored in this study with a model compound of 2,4,5-trichlorobiphenyl (PCB29). PCB-contaminated soil was treated in a quartz reactor by microwave irradiation at 2450MHz with the addition of granular activated carbon (GAC). In this procedure, GAC acted as microwave absorbent for reaching high temperature and reductant for dechlorination. A sheltered type-K thermocouple was applied to record the temperature rising courses. It was shown that the addition of GAC could effectively promote the temperature rising courses. The determination of PCB residues in soil by gas chromatography (GC) revealed that rates of PCB removal were highly dependent on microwave power, soil moisture content, and the amount of GAC added. GC with mass spectrum (MS) detector and ion chromatography were employed for the analysis of degradation intermediates and chlorine ions, respectively. It was suggested that microwave irradiation with the assistance of activated carbon might be a potential technology for the remediation of PCB-contaminated soil.

  18. [Microbial degradation of 3-phenoxybenzoic acid--A review].

    Science.gov (United States)

    Deng, Weiqin; Liu, Shuliang; Yao, Kai

    2015-09-04

    3-phenoxybenzoic acid (3-PBA) with estrogen toxicity is one of the intermediate products of most pyrethroid pesticides. 3-PBA is difficult to degrade in the natural environment, and threatens food safety and human health. Microbial degradation of pyrethroids and their intermediate product (3-PBA) has become a hot topic in recent years. Here, we reviewed microbial species, degrading enzymes and degradation genes, degradation pathways of 3-PBA degrading and the application of 3-PBA degradation strains. This article provides references for the study of 3-PBA degradation by microorganisms.

  19. Proteomics and Metabolomics Analyses to Elucidate the Desulfurization Pathway of Chelatococcus sp.

    Directory of Open Access Journals (Sweden)

    Naba K Bordoloi

    Full Text Available Desulfurization of dibenzothiophene (DBT and alkylated DBT derivatives present in transport fuel through specific cleavage of carbon-sulfur (C-S bonds by a newly isolated bacterium Chelatococcus sp. is reported for the first time. Gas chromatography-mass spectrometry (GC-MS analysis of the products of DBT degradation by Chelatococcus sp. showed the transient formation of 2-hydroxybiphenyl (2-HBP which was subsequently converted to 2-methoxybiphenyl (2-MBP by methylation at the hydroxyl group of 2-HBP. The relative ratio of 2-HBP and 2-MBP formed after 96 h of bacterial growth was determined at 4:1 suggesting partial conversion of 2-HBP or rapid degradation of 2-MBP. Nevertheless, the enzyme involved in this conversion process remains to be identified. This production of 2-MBP rather than 2-HBP from DBT desulfurization has a significant metabolic advantage for enhancing the growth and sulfur utilization from DBT by Chelatococcus sp. and it also reduces the environmental pollution by 2-HBP. Furthermore, desulfurization of DBT derivatives such as 4-M-DBT and 4, 6-DM-DBT by Chelatococcus sp. resulted in formation of 2-hydroxy-3-methyl-biphenyl and 2-hydroxy -3, 3/- dimethyl-biphenyl, respectively as end product. The GC and X-ray fluorescence studies revealed that Chelatococcus sp. after 24 h of treatment at 37°C reduced the total sulfur content of diesel fuel by 12% by per gram resting cells, without compromising the quality of fuel. The LC-MS/MS analysis of tryptic digested intracellular proteins of Chelatococcus sp. when grown in DBT demonstrated the biosynthesis of 4S pathway desulfurizing enzymes viz. monoxygenases (DszC, DszA, desulfinase (DszB, and an NADH-dependent flavin reductase (DszD. Besides, several other intracellular proteins of Chelatococcus sp. having diverse biological functions were also identified by LC-MS/MS analysis. Many of these enzymes are directly involved with desulfurization process whereas the other enzymes

  20. Polychlorinated biphenyls (PCBs) in the frame of the dismantling of nuclear facilities; Polychlorierte Biphenyle (PCB) beim Rueckbau von kerntechnischen Anlagen

    Energy Technology Data Exchange (ETDEWEB)

    Hagenbart, Lars; Held, Christian; Reichert, Alexander [WAK-Rueckbau- und Entsorgungs-GmbH, Eggenstein-Leopoldshafen (Germany)

    2013-08-01

    During construction and maintenance of nuclear facilities PCB (polychlorinated biphenyls) containing paints were used in a large extent in the past. The WAK dismantling and disposal Company has dismantles such facilities and identified the PCB in the buildings. Besides the radionuclides the conventional hazardous material group of the PCBs has also to be disposed. The respective legal regulations have to be considered. In the frame of the contribution the radiological release of building structures with respect to re-use or demolition and residual PCB containing materials is discussed. The radiological disposal in final repositories and the conventional disposal regulations for releasable residual wastes are reported.

  1. Bacteria-mediated bisphenol A degradation.

    Science.gov (United States)

    Zhang, Weiwei; Yin, Kun; Chen, Lingxin

    2013-07-01

    Bisphenol A (BPA) is an important monomer in the manufacture of polycarbonate plastics, food cans, and other daily used chemicals. Daily and worldwide usage of BPA and BPA-contained products led to its ubiquitous distribution in water, sediment/soil, and atmosphere. Moreover, BPA has been identified as an environmental endocrine disruptor for its estrogenic and genotoxic activity. Thus, BPA contamination in the environment is an increasingly worldwide concern, and methods to efficiently remove BPA from the environment are urgently recommended. Although many factors affect the fate of BPA in the environment, BPA degradation is mainly depended on the metabolism of bacteria. Many BPA-degrading bacteria have been identified from water, sediment/soil, and wastewater treatment plants. Metabolic pathways of BPA degradation in specific bacterial strains were proposed, based on the metabolic intermediates detected during the degradation process. In this review, the BPA-degrading bacteria were summarized, and the (proposed) BPA degradation pathway mediated by bacteria were referred.

  2. Organochlorine pesticides and polychlorinated biphenyls in sewage sludge from Egypt.

    Science.gov (United States)

    Barakat, Assem O; Khairy, Mohammed A; Mahmoud, Mahmoud R

    2017-07-03

    The purpose of this study was to determine the levels, distribution and toxicological potential of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in sewage sludge samples from several WWTPs in the Alexandria area, Egypt. The POPs of interest were 26 PCBs and 16 OCPs. Analyses were performed by gas chromatography with electron impact mass spectrometric detection in the selected ion monitoring mode (GC-MS-SIM) using deuterated organochlorines as internal standards. Total concentrations of OCPs and Σ7 PCBs (ICES) in sludge ranged from 44.2 to 489 μg/kg dw. and 5,600 to 11,000 μg/kg dw., respectively. The highest concentration levels were found for PCBs, HCHs, DDTs, and HCB, in this order. The PCB homologue profiles in sludge samples were dominated by penta- and hexa-chlorinated biphenyls. Seasonal variations were observed for OCPs with higher levels in summer, which reflects more usage in warmer climates. Composite profiles of OCP metabolites indicated new inputs of lindane and technical endosulfan and earlier usage of DDT and technical chlordane. Contamination levels of OCPs and PCBs for Egyptian sludge can be categorized as moderate to high compared to other countries worldwide. The OCP content in none of the samples exceeded limits set by the European Commission for use of sludge in agriculture; while all the concentrations of PCBs in sludge samples were higher by one order of magnitude than the upper limit for land application.

  3. Identification and genetic characterization of phenol- degrading ...

    African Journals Online (AJOL)

    SAURABH

    2013-02-20

    Feb 20, 2013 ... compared with LmPH gene of Pseudomonas sp.CF600. Reversed phase high performance liquid chromatography showed that the isolate can degrade phenol through catechol ortho fission pathway. In this paper, we reported about the new strain of Acinetobacter sp. capable of degrading phenol (9.5 mM.

  4. Assessment of hydroxylated metabolites of polychlorinated biphenyls as potential xenoestrogens: a QSAR comparative analysis∗.

    Science.gov (United States)

    Ruiz, P; Myshkin, E; Quigley, P; Faroon, O; Wheeler, J S; Mumtaz, M M; Brennan, R J

    2013-01-01

    Alternative methods, including quantitative structure-activity relationships (QSAR), are being used increasingly when appropriate data for toxicity evaluation of chemicals are not available. Approximately 40 mono-hydroxylated polychlorinated biphenyls (OH-PCBs) have been identified in humans. They represent a health and environmental concern because some of them have been shown to have agonist or antagonist interactions with human hormone receptors. This could lead to modulation of steroid hormone receptor pathways and endocrine system disruption. We performed QSAR analyses using available estrogenic activity (human estrogen receptor ER alpha) data for 71 OH-PCBs. The modelling was performed using multiple molecular descriptors including electronic, molecular, constitutional, topological, and geometrical endpoints. Multiple linear regressions and recursive partitioning were used to best fit descriptors. The results show that the position of the hydroxyl substitution, polarizability, and meta adjacent un-substituted carbon pairs at the phenolic ring contribute towards greater estrogenic activity for these chemicals. These comparative QSAR models may be used for predictive toxicity, and identification of health consequences of PCB metabolites that lack empirical data. Such information will help prioritize such molecules for additional testing, guide future basic laboratory research studies, and help the health/risk assessment community understand the complex nature of chemical mixtures.

  5. Oxidation of dibenzothiophene (DBT by Serratia marcescens UCP 1549 formed biphenyl as final product

    Directory of Open Access Journals (Sweden)

    de Araújo Hélvia W

    2012-05-01

    Full Text Available Abstract Background The desulphurization of dibenzothiophene (DBT, a recalcitrant thiophenic fossil fuel component by Serratia marcescens (UCP 1549 in order for reducing the Sulphur content was investigated. The Study was carried out establishing the growth profile using Luria Bertani medium to different concentrations of DBT during 120 hours at 28°C, and orbital Shaker at 150 rpm. Results The results indicated that concentrations of DBT 0.5, 1.0 and 2.0 mM do not affected the growth of the bacterium. The DBT showed similar Minimum Inhibitory Concentration (MIC and Minimum Bactericidal Concentration (MCB (3.68 mM. The desulphurization of DBT by S. marcescens was used with 96 hours of growth on 2 mM of DBT, and was determined by gas chromatography (GC and GC-mass spectrometry. In order to study the desulphurization process by S. marcescens was observed the presence of a sulfur-free product at 16 hours of cultivation. Conclusions The data suggests the use of metabolic pathway “4S” by S. marcescens (UCP 1549 and formed biphenyl. The microbial desulphurization process by Serratia can be suggest significant reducing sulphur content in DBT, and showed promising potential for reduction of the sulfur content in diesel oil.

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

    Energy Technology Data Exchange (ETDEWEB)

    Mikes, Ondrej; Cupr, Pavel [RECETOX, Research Centre for Environmental Chemistry and Ecotoxicology, Masaryk University, Kamenice 126/3, 625 00 Brno (Czech Republic); Trapp, Stefan [Department of Environmental Engineering, Technical University of Denmark, Miljoevej 113, DK-2800 Kgs. Lyngby (Denmark); Klanova, Jana [RECETOX, Research Centre for Environmental Chemistry and Ecotoxicology, Masaryk University, Kamenice 126/3, 625 00 Brno (Czech Republic)], E-mail: klanova@recetox.muni.cz

    2009-02-15

    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, defined as a ratio between the contaminant concentration in the plant tissue and concentration in soil) was determined for roots, edible bulbs and shoots. Root BCF values were constant and not correlated to log K{sub OW}. A negative correlation between BCF and log K{sub OW} was found for edible bulbs. Shoot BCF values were rather constant and varied between 0.01 and 0.22. Resuspended soil particles may facilitate the transport of chemicals from soil to shoots. Elevated POP concentrations found in shoots of radishes grown in the control plot support the hypothesis that the uptake from air was more significant for shoots than the one from soil. The uptake of POPs from air was within the range of theoretical values predicted from log K{sub OA}. - Uptake from air represented for majority of persistent organochlorines a dominant pathway into shoots while uptake from soil was dominant for roots.

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

    International Nuclear Information System (INIS)

    Mikes, Ondrej; Cupr, Pavel; Trapp, Stefan; Klanova, Jana

    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 β-hexachlorocyclohexane. Bioconcentration factor (BCF, defined as a ratio between the contaminant concentration in the plant tissue and concentration in soil) was determined for roots, edible bulbs and shoots. Root BCF values were constant and not correlated to log K OW . A negative correlation between BCF and log K OW was found for edible bulbs. Shoot BCF values were rather constant and varied between 0.01 and 0.22. Resuspended soil particles may facilitate the transport of chemicals from soil to shoots. Elevated POP concentrations found in shoots of radishes grown in the control plot support the hypothesis that the uptake from air was more significant for shoots than the one from soil. The uptake of POPs from air was within the range of theoretical values predicted from log K OA . - Uptake from air represented for majority of persistent organochlorines a dominant pathway into shoots while uptake from soil was dominant for roots

  8. Environmental fate and global distribution of polychlorinated biphenyls.

    Science.gov (United States)

    Beyer, Angelika; Biziuk, Marek

    2009-01-01

    -chlorinated PCBs are often more resistant to degradation and volatilization and sorb more strongly to particulate matter. Some more-chlorinated PCBs tend to bioaccumulate to greater concentrations in tissues of animals than do low-molecular-weight ones. The more-heavily chlorinated PCBs can also biomagnify in food webs. Other high-molecular-weight congeners have specific structures that render them susceptible to metabolism by such species as fish, crustacea, birds, and mammals. In recent years, there has been substantial progress made in understanding the human health and ecological effects of PCBs and their environmental dynamics. However, risk assessments based only on the original PCB mixture that entered the environment are not sufficient to determine either (1) the persistence or toxicity of the weathered PCB mixture actually present in the environment, or (2) the risks to humans and the ecosystem posed by the weathered mixture. In this paper, we have reviewed the status of current knowledge on PCBs with regard to environmental inputs, global distribution, and environmental fate. We conclude that to know and understand the critical environmental fate pathways for PCBs, both a combination of field studies in real ecosystems and more controlled laboratory investigations are needed. For the future, both revised and new models on how PCBs behave in the environment are needed. Finally, more information on ow PCBs affect relevant physiological and behavioral characteristics of organisms tha are susceptible to contamination are needed.

  9. Degraded Crater

    Science.gov (United States)

    2004-01-01

    21 October 2004 Near the center of this Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image lies the degraded remnants of an old meteor impact crater. The terrain in which it occurs is a heavily eroded, north middle-latitude surface. The image is located in the fretted terrains north of Arabia Terra near 41.3oN, 305.8oW. The image covers an area about 3 km (1.9 mi) wide and sunlight illuminates the scene from the lower left.

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

    International Nuclear Information System (INIS)

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

    2012-01-01

    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 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.

  11. Vapor solvent decontamination of PCB [polychlorinated biphenyls] transformer components

    International Nuclear Information System (INIS)

    Green, G.R.; Green, G.R.

    1992-01-01

    A process is provided to recover reclaimable material from discarded transformers containing PCB (polychlorinated biphenyl) insulating oils and to minimize the volume of materials which are subject to environmental regulation upon disposal. According to the invention, the transformer is drained and given an initial cleaning. The internal parts are removed and cleaned a second time as is the empty transformer casing. Recoverable materials such as aluminum and copper are cleaned to less than 10 μg of PCB per 100 cm 2 , allowing these materials to be recycled rather than buried. Almost all of the remaining nonmetallic materials are combustible solids or liquids which can be destroyed by incineration. The cleaning is accomplished using trichloroethylene solvent, chosen for its low boiling point which makes it easy to recycle using an isothermal separator. The removed transformer parts are cleaned in a secondary cleaning station consisting of 3 separate sections including tumbling baskets. 2 figs

  12. Delineation of Steroid-Degrading Microorganisms through Comparative Genomic Analysis

    Directory of Open Access Journals (Sweden)

    Lee H. Bergstrand

    2016-03-01

    Full Text Available Steroids are ubiquitous in natural environments and are a significant growth substrate for microorganisms. Microbial steroid metabolism is also important for some pathogens and for biotechnical applications. This study delineated the distribution of aerobic steroid catabolism pathways among over 8,000 microorganisms whose genomes are available in the NCBI RefSeq database. Combined analysis of bacterial, archaeal, and fungal genomes with both hidden Markov models and reciprocal BLAST identified 265 putative steroid degraders within only Actinobacteria and Proteobacteria, which mainly originated from soil, eukaryotic host, and aquatic environments. These bacteria include members of 17 genera not previously known to contain steroid degraders. A pathway for cholesterol degradation was conserved in many actinobacterial genera, particularly in members of the Corynebacterineae, and a pathway for cholate degradation was conserved in members of the genus Rhodococcus. A pathway for testosterone and, sometimes, cholate degradation had a patchy distribution among Proteobacteria. The steroid degradation genes tended to occur within large gene clusters. Growth experiments confirmed bioinformatic predictions of steroid metabolism capacity in nine bacterial strains. The results indicate there was a single ancestral 9,10-seco-steroid degradation pathway. Gene duplication, likely in a progenitor of Rhodococcus, later gave rise to a cholate degradation pathway. Proteobacteria and additional Actinobacteria subsequently obtained a cholate degradation pathway via horizontal gene transfer, in some cases facilitated by plasmids. Catabolism of steroids appears to be an important component of the ecological niches of broad groups of Actinobacteria and individual species of Proteobacteria.

  13. 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.

  14. 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...

  15. CATALYTIC STEAM REFORMING OF CHLOROCARBONS: POLYCHLORINATED BIPHENYLS (PCBS). (R826694C633)

    Science.gov (United States)

    Experiments with commercial askarals (Aroclors 1221, 1248 and 1254) have confirmed the feasibility of catalytic steam reforming as a method for destroying polychlorinated biphenyls (PCBs). Rhodium, platinum and nickel supported on 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.M. Berbers (Guy); 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

  16. Notifications Dated October 2, 2014 Submitted by We Energies to Dispose of Polychlorinated Biphenyl Remediation Waste

    Science.gov (United States)

    Disposal Notifications Dated October 2, 2014 for We Energies and the Utility Solid Waste Group Members’ Risk-Based Approvals to Dispose of Polychlorinated Biphenyl Remediation Waste at the Waste Management Disposal Sites in Menomonee Falls and Franklin, WI

  17. Influence of Aroclor 1242 Concentration on Polychlorinated Biphenyl Biotransformations in Hudson River Test Tube Microcosms

    Science.gov (United States)

    Fish, K. M.

    1996-01-01

    When 93.3 to 933 (mu)mol of Aroclor 1242 per kg was added to Hudson River sediment test tube microcosms, the rates of polychlorinated biphenyl biotransformations increased with increasing Aroclor 1242 concentration after a 4- to 8-week acclimation period. In contrast, when 37.3 (mu)mol of Aroclor 1242 per kg was added, polychlorinated biphenyl biotransformations occurred at slow constant rates. PMID:16535387

  18. Polychlorinated biphenyls and pesticides in surficial coastal sediments of the Ligurian Sea

    Energy Technology Data Exchange (ETDEWEB)

    Bertolotto, R.M.; Cuneo, C.; Albanese, S. [ARPAL, Direzione Scientifica, Genova (Italy); Magherini, A. [ARPAL, Dipartimento di Genova, Genova (Italy); Frignani, M.; Bellucci, L.G.; Alvarado-Aguilar, D. [ISMAR, Sezione di Geologia Marina, Bologna (Italy)

    2004-09-15

    Polychlorinated biphenyls (PCBs) and chlorinated pesticides, such as DDT and its analogues, are organic contaminants widespread throughout the terrestrial and oceanic environments due to their common use and their resistance to degradation. Since harmful effects have been associated to these chemicals and well documented, they are classified as priority pollutants by both the US Environmental Protection Agency (EPA) and the European Union. Because of the very low solubility in water and the tendency to adsorb onto sediment particles, the ultimate fate of both PCBs and DDTs in the marine environment is the incorporation into sediments. Hence, the concentrations of these chlorinate chemicals in bottom sediments can provide an insight on the quality of the environment and the potential threat to marine organisms and human beings. The Ligurian Sea belongs to the north part of the western Mediterranean. The coastal morphology of the Liguria Region is rather variable, and frequently cliffs drop sheer to the sea. The limited width of the coastal zone, comprised between the sea and the mountains, determined a gathering of the urban areas with a consequent concentration of both civil and industrial presence in a narrow but highly populated territory. In particular Genova, but also other cities have a long history of industrial and harbour activities, whereas long tracts of the coast are dedicated to tourism. The circulation of the Ligurian Sea is rather well known. In particular, surface and intermediate currents follow a cyclonic circulation. However local circulation is the true responsible of the dispersion of sediment material along the coast, and these alongshore currents often cause an eastward oriented transport. The Ligurian coastal zone is very developed, and hosts all sort of industrial, agricultural and tourist activities that can be sources of persistent organochlorine chemicals. Therefore, the purpose of this study was to assess concentrations, distributions

  19. Paddy field – A natural sequential anaerobic–aerobic bioreactor for polychlorinated biphenyls transformation

    International Nuclear Information System (INIS)

    Chen, Chen; Yu, Chunna; Shen, Chaofeng; Tang, Xianjin; Qin, Zhihui; Yang, Kai; Hashmi, Muhammad Zaffar; Huang, Ronglang; Shi, Huixiang

    2014-01-01

    The environmental pollution and health risks caused by the improper disposal of electric and electronic waste (e-waste) have become urgent issues for the developing countries. One of the typical pollutants, polychlorinated biphenyls (PCBs), is commonly found in farmland in Taizhou, a major hotspot of e-waste recycling in China. This study investigated the amount of PCB residue in local farmlands. Biotransformation of PCBs was further studied under different water management conditions in paddy field with or without rice cultivation, with a special focus on the alternating flooded and drying processes. It was found that paddy field improved the attenuation of PCBs, especially for highly chlorinated congeners. In the microcosm experiment, 40% or more of the initial total PCBs was removed after sequential flood–drying treatments, compared to less than 10% in the sterilized control and 20% in the constant-drying system. Variation in the quantity of PCBs degrading and dechlorinating bacterial groups were closely related to the alteration of anaerobic–aerobic conditions. These results suggested that alternating anoxic–oxic environment in paddy field led to the sequential aerobic–anaerobic transformation of PCBs, which provided a favorable environment for natural PCB attenuation. - Highlights: • Paddy fields hold significantly lower level of PCBs than drylands, especially highly-chlorinated PCBs. • Microbial dechlorination of PCBs is favored under flooded conditions in paddy field. • Aerobic biodegradation of PCBs is benefited under dry conditions in paddy field. • PCBs dechlorination rate is accelerated in rice planted paddy field compared to the unplanted one. • Alternating anoxic–oxic environment in paddy field led to the sequential aerobic–anaerobic transformation of PCBs. - Alternating anoxic–oxic environment led to the sequential aerobic–anaerobic transformation of PCBs in paddy field, which could act as a natural sequential anaerobic

  1. Reversed-phase liquid chromatography with electrospray mass detection and 1H and 13C NMR characterization of new process-related impurities, including forced degradants of efavirenz: related substances correlated to the synthetic pathway.

    Science.gov (United States)

    Gadapayale, Kamalesh; Kakde, Rajendra; Sarma, V U M

    2015-01-01

    In this study, a stability-indicating reversed-phase liquid chromatographic electrospray mass spectrometric method was developed and validated for the determination of process-related impurities and forced degradants of Efavirenz in bulk drugs. Efavirenz was subjected to acid, alkaline hydrolysis, H2O2 oxidation, photolysis, and thermal stress. Significant degradation was observed during alkaline hydrolysis, and the degradants were isolated on a mass-based purification system and characterized by high-resolution mass spectrometry, positive electrospray ionization tandem mass spectrometry, and (1)H and (13)C NMR spectroscopy. Accurate mass measurement and NMR spectroscopy revealed the possible structure of process-related impurities and degradant under stress conditions. The acceptable separation was accomplished on Waters bondapak C18 column (250 mm × 4.6 mm; 5 μm), using 5 mM ammonium acetate and acetonitrile as a mobile phase in a gradient elution mode at a flow rate of 1.0 mL/min. The eluents were monitored by diode array detector at 247 nm and quantitation limits were obtained in the range of 0.1-2.5 μg/mL for Efavirenz, degradants, and process-related impurities. The liquid chromatography method was validated with respect to accuracy, precision, linearity, robustness, and limits of detection and quantification as per International Conference on Harmonization guidelines. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Intrinsic immunogenicity of rapidly-degradable polymers evolves during degradation.

    Science.gov (United States)

    Andorko, James I; Hess, Krystina L; Pineault, Kevin G; Jewell, Christopher M

    2016-03-01

    Recent studies reveal many biomaterial vaccine carriers are able to activate immunostimulatory pathways, even in the absence of other immune signals. How the changing properties of polymers during biodegradation impact this intrinsic immunogenicity is not well studied, yet this information could contribute to rational design of degradable vaccine carriers that help direct immune response. We use degradable poly(beta-amino esters) (PBAEs) to explore intrinsic immunogenicity as a function of the degree of polymer degradation and polymer form (e.g., soluble, particles). PBAE particles condensed by electrostatic interaction to mimic a common vaccine approach strongly activate dendritic cells, drive antigen presentation, and enhance T cell proliferation in the presence of antigen. Polymer molecular weight strongly influences these effects, with maximum stimulation at short degradation times--corresponding to high molecular weight--and waning levels as degradation continues. In contrast, free polymer is immunologically inert. In mice, PBAE particles increase the numbers and activation state of cells in lymph nodes. Mechanistic studies reveal that this evolving immunogenicity occurs as the physicochemical properties and concentration of particles change during polymer degradation. This work confirms the immunological profile of degradable, synthetic polymers can evolve over time and creates an opportunity to leverage this feature in new vaccines. Degradable polymers are increasingly important in vaccination, but how the inherent immunogenicity of polymers changes during degradation is poorly understood. Using common rapidly-degradable vaccine carriers, we show that the activation of immune cells--even in the absence of other adjuvants--depends on polymer form (e.g., free, particulate) and the extent of degradation. These changing characteristics alter the physicochemical properties (e.g., charge, size, molecular weight) of polymer particles, driving changes in

  3. A novel method to identify hub pathways of rheumatoid arthritis based on differential pathway networks.

    Science.gov (United States)

    Wei, Shi-Tong; Sun, Yong-Hua; Zong, Shi-Hua

    2017-09-01

    The aim of the current study was to identify hub pathways of rheumatoid arthritis (RA) using a novel method based on differential pathway network (DPN) analysis. The present study proposed a DPN where protein‑protein interaction (PPI) network was integrated with pathway‑pathway interactions. Pathway data was obtained from background PPI network and the Reactome pathway database. Subsequently, pathway interactions were extracted from the pathway data by building randomized gene‑gene interactions and a weight value was assigned to each pathway interaction using Spearman correlation coefficient (SCC) to identify differential pathway interactions. Differential pathway interactions were visualized using Cytoscape to construct a DPN. Topological analysis was conducted to identify hub pathways that possessed the top 5% degree distribution of DPN. Modules of DPN were mined according to ClusterONE. A total of 855 pathways were selected to build pathway interactions. By filtrating pathway interactions of weight values >0.7, a DPN with 312 nodes and 791 edges was obtained. Topological degree analysis revealed 15 hub pathways, such as heparan sulfate/heparin‑glycosaminoglycan (HS‑GAG) degradation, HS‑GAG metabolism and keratan sulfate degradation for RA based on DPN. Furthermore, hub pathways were also important in modules, which validated the significance of hub pathways. In conclusion, the proposed method is a computationally efficient way to identify hub pathways of RA, which identified 15 hub pathways that may be potential biomarkers and provide insight to future investigation and treatment of RA.

  4. Interacting influence of potassium and polychlorinated biphenyl on cortisol and aldosterone biosynthesis

    International Nuclear Information System (INIS)

    Li, L.-A.; Lin, Tsu-Chun Emma

    2007-01-01

    Giving human adrenocortical H295R cells 14 mM KCl for 24 h significantly induced not only aldosterone biosynthesis but also cortisol biosynthesis. Pre-treating the cells with polychlorinated biphenyl 126 (PCB126) further increased potassium-induced aldosterone and cortisol productions in a dose-dependent manner, but all examined concentrations of PCB126 had little effect on the yields of precursor steroids progesterone and 17-OH-progesterone. Subsequent examinations revealed that CYP11B1 and CYP11B2 genes, responsible for the respective final steps of the cortisol and aldosterone biosynthetic pathways, exhibited increased responsiveness to PCB126 under high potassium. While 10 -5 M PCB126 was needed to induce a significant increase in the basal mRNA abundance of either gene, PCB126 could enhance potassium-induced mRNA expression of CYP11B1 at 10 -7 M and CYP11B2 at 10 -9 M. Actually, potassium and PCB126 synergistically upregulated mRNA expression of both genes. Potassium raised the transcriptional rates of CYP11B1 and CYP11B2 probably through a conserved Ad5 cis-element, whereas PCB126 appeared to regulate these two genes at the post-transcriptional level. Positive potassium-PCB126 synergism was also detected in CYP11B2 enzyme activity estimated by aldosterone/progesterone ratio. In contrast, potassium and PCB126 increased CYP11B1 enzyme activity or cortisol/17-OH-progesterone ratio additively. Moreover, potassium improved the time effect of PCB126 on gene expression and enzyme activity of CYP11B2, but not the PCB126 time response of CYP11B1. These data demonstrated that potassium differentially enhanced the potency of PCB126 to induce CYP11B1- and CYP11B2-mediated steroidogenesis

  5. Polychlorinated biphenyls in two salt marsh sediments of the Venice Lagoon.

    Science.gov (United States)

    Mugnai, Cristian; Giuliani, Silvia; Bellucci, Luca G; Carraro, Claudio; Favotto, Maurizio; Frignani, Mauro

    2011-10-01

    Polychlorinated biphenyls (PCBs) were measured in two dated salt marsh cores of the Venice Lagoon to assess their input chronology and to evaluate the importance of atmospheric deposition as a source. Sampling sites were chosen in order to evidence the differences between areas located leeward and windward with respect to inputs originating in both the city of Venice and the industrial area. Concentrations of PCB indicators (0.13-15.6 ng g⁻¹) increased gradually from the 1930s, reached maxima from the 1950s to the late 1970s, and then decreased. PCB loadings to marshes are driven by both the atmospheric deposition and the resuspension of subtidal sediments, this latter being more important for heavier congeners. The downwind marsh recorded higher fluxes (0.06-9.72 ng cm⁻² year⁻¹) than the upwind one (0.01-0.53 ng cm⁻² year⁻¹). Recent fluxes are rather consistent with bulk deposition measurements. A higher contribution of CB-101 and CB-118 was detected in the intermediate layers of the downwind site, suggesting a different PCB source for the corresponding time interval. In the other marsh, PCBs showed a rather constant composition at all levels (mostly CB-153, CB-138 and CB-180), accounting for a regional influence. Deep layers showed an enrichment of higher chlorinated congeners at both sites, whereas recent samples conserve the patterns typical of surficial and subsurficial subtidal sediments. The scientific approach adopted in this research can be considered as a sort of methodological procedure for the determination of fluxes and pathways of PCBs through the study of marsh cores.

  6. Modeling Population-Level Consequences of Polychlorinated Biphenyl Exposure in East Greenland Polar Bears.

    Science.gov (United States)

    Pavlova, Viola; Grimm, Volker; Dietz, Rune; Sonne, Christian; Vorkamp, Katrin; Rigét, Frank F; Letcher, Robert J; Gustavson, Kim; Desforges, Jean-Pierre; Nabe-Nielsen, Jacob

    2016-01-01

    Polychlorinated biphenyls (PCBs) can cause endocrine disruption, cancer, immunosuppression, or reproductive failure in animals. We used an individual-based model to explore whether and how PCB-associated reproductive failure could affect the dynamics of a hypothetical polar bear (Ursus maritimus) population exposed to PCBs to the same degree as the East Greenland subpopulation. Dose-response data from experimental studies on a surrogate species, the mink (Mustela vision), were used in the absence of similar data for polar bears. Two alternative types of reproductive failure in relation to maternal sum-PCB concentrations were considered: increased abortion rate and increased cub mortality. We found that the quantitative impact of PCB-induced reproductive failure on population growth rate depended largely on the actual type of reproductive failure involved. Critical potencies of the dose-response relationship for decreasing the population growth rate were established for both modeled types of reproductive failure. Comparing the model predictions of the age-dependent trend of sum-PCBs concentrations in females with actual field measurements from East Greenland indicated that it was unlikely that PCB exposure caused a high incidence of abortions in the subpopulation. However, on the basis of this analysis, it could not be excluded that PCB exposure contributes to higher cub mortality. Our results highlight the necessity for further research on the possible influence of PCBs on polar bear reproduction regarding their physiological pathway. This includes determining the exact cause of reproductive failure, i.e., in utero exposure versus lactational exposure of offspring; the timing of offspring death; and establishing the most relevant reference metrics for the dose-response relationship.

  7. Xenobiotic action on steroid hormone synthesis and sulfonation the example of lead and polychlorinated biphenyls.

    Science.gov (United States)

    Romeo, L; Catalani, S; Pasini, F; Bergonzi, R; Perbellini, L; Apostoli, P

    2009-04-01

    In the present study, the metabolism of steroid hormones has been investigated to determine whether and how xenobiotics like lead (Pb) and polychlorinated biphenyls (PCBs) interfere with steroid hormone biotransformation in humans. Three groups of subjects were tested for concentration of urinary total steroids, 17-ketosteroids (n = 5), pregnane derivates (n = 6), 17-hydroxycorticosteroids (n = 11) and their sulfonated compounds: 14 workers exposed to lead, with a mean Pb blood concentration (PbB) of 29.21 microg/dl; 15 subjects exposed to PCBs, with a mean PCB blood concentration (PCBB) of 61.69 microg/l; a control group (n = 25). The urinary concentrations of 17-ketosteroids and 17-hydroxycorticosteroids were significantly lower in the PCB-exposed groups. There were significantly fewer sulfonated 17-hydroxycorticosteroids in the subjects exposed to PCBs as compared to the controls, while the percentage of sulfonated steroids was lower for both 17-ketosteroids and 17-hydroxycorticosteroids in the PCB-exposed subjects, but only for the 17-hydroxycorticosteroids in the group of subjects exposed to Pb (P < 0.05). Pregnane derivate urinary concentrations did not differ between the three groups. Our results suggest that PCBs and Pb act on steroid hormone metabolism with different effects and only partially using the same hormone pathways; they may cause changes in endogenous hormone homeostasis and interfere with the xenobiotic phase II of detoxification. PCBs interfere on a larger number of steroids and cause more significant effects than Pb. It is likely that different mechanisms are involved in steroid hormone metabolism interference.

  8. Advances of naphthalene degradation in Pseudomonas putida ND6

    Science.gov (United States)

    Song, Fu; Shi, Yifei; Jia, Shiru; Tan, Zhilei; Zhao, Huabing

    2018-03-01

    Naphthalene is one of the most common and simple polycyclic aromatic hydrocarbons. Degradation of naphthalene has been greatly concerned due to its economic, free-pollution and its fine effect in Pseudomonas putida ND6. This review summarizes the development history of naphthalene degradation, the research progress of naphthalene degrading gene and naphthalene degradation pathway of Pseudomonas putida ND6, and the researching path of this strain. Although the study of naphthalene degradation is not consummate in Pseudomonas putida ND6, there is a potential capability for Pseudomonas putida ND6 to degrade the naphthalene in the further research.

  9. Polychlorinated Biphenyls Water Pollution along the River Nile, Egypt

    Science.gov (United States)

    Megahed, Ayman Mohamed; Dahshan, Hesham; Abd-El-Kader, Mahdy A.; Abd-Elall, Amr Mohamed Mohamed; Elbana, Mariam Hassan; Nabawy, Ehab; Mahmoud, Hend A.

    2015-01-01

    Ten polychlorinated biphenyl (PCB) congeners were determined in water samples collected along the River Nile using gas chromatography-electron capture detector (GC-ECD). PCB concentrations ranged from 14 to 20 μg/L, which were higher than those reported in previous studies, indicating serious PCB pollution in the River Nile. PCB congener profiles varied depending on the sampling sties. PCB-138 was the predominant congener accounting for more than 18% of total PCBs. The composition of PCB congeners in the water revealed that highly chlorinated PCB technical mixtures such as Aroclor 1254 was the main PCB production historically used in Egypt. An increasing trend in PCB levels from the upper stream to the Nile estuaries was observed. The calculated flux of PCBs indicated that 6.8 tons of PCBs is dumped into the Mediterranean Sea each year from the River Nile. The hazard quotients and carcinogenic risk caused by PCB pollution in the River Nile were above the acceptable level indicating that PCBs in the River Nile water pose adverse health effects for all age groups. Our findings revealed that PCBs possess a serious risk to the Egyptian population that depends mainly on the River Nile as a source of water. Thus, stricter legislation and regulatory controls should be applied to reduce the risk of PCBs in Egypt. PMID:26798844

  10. Environmental contamination of ready meals by polychlorinated biphenyls (PCBs).

    Science.gov (United States)

    Adenugba, Adeola A; McMartin, Dena W; Beck, Angus

    2012-01-01

    The level of polychlorinated biphenyls (PCBs) contamination in ready meals was investigated to determine exposure compared to other foodstuffs. Chilled ready meals from nine categories (ambient, Chinese, Indian, Traditional UK, Italian, American Tex-Mex, Vegetarian and Organic), and three samples within each category were Soxhlet extracted in triplicate with hexane for 24 h, followed by a clean-up on deactivated silica gel. The cleaned extracts were concentrated to 1 ml under N(2) gas and analyzed on gas chromatography mass spectrometry (GC-MS) for 7 target PCBs (congeners 28, 52, 101, 118, 153, 138, and 180). Individual congener concentrations ranged from non-detectable to 0.40 ng g(-1) (wet weight). The cumulative concentration of all congeners (ΣPCBs) ranged between 0.20 and 1.00 ng g(-1) (wet weight). These values translate into exposure levels of less than 1 μg kg(-1)day(-1) for reference men and women of 70 and 57 kg, respectively. This preliminary study demonstrates that ready meals, like many other foods, are contaminated by PCBs and may represent an important route of human exposure given contemporary changes in consumer food choice. Even though low levels of contamination were observed, long-term exposure for population groups consuming a high volume of ready meals may have cause for concern regarding chronic health risks.

  11. [Polychlorinated biphenyls and organochlorine pesticides in soils in Poland].

    Science.gov (United States)

    Kawano, M; Brudnowska, B; Falandysz, J; Wakimoto, T

    2000-01-01

    The concentrations of organochlorine pesticides such as DDTs, HCHs, CHLs, HCBz and polychlorinated biphenyls (PCBs) were determined in 59 soil samples collected in Poland in 1990-1994 to understand the scale of contamination, spatial distribution and sources of these compounds. Identification and quantification of organochlorines were carried out using HRGC-ECD (63Ni) and HRGC-LRMS. All soil samples were contaminated by DDTs, PCBs and HCHs, while HCBz and CHLs were absent in a few samples. DDTs dominated as organochlorine residues in Polish soil and on the concentration of other insecticides was two orders of magnitude lower. Percentage composition of DDTs (about 60% of p,p'-DDT) indicates a very slow metabolism of DDT in Polish soils. Spatial distribution of HCHs in Poland is similar to distribution of DDTs, while HCBz and CHLs are rather evenly distributed. PCBs concentrations in soil of the Former Soviet Union Army Base are 10 times higher then in urban soils, and 100 times higher then in cultivated and forests soils.

  12. Preconception maternal polychlorinated biphenyl concentrations and the secondary sex ratio

    International Nuclear Information System (INIS)

    Taylor, Kira C.; Jackson, Leila W.; Lynch, Courtney D.; Kostyniak, Paul J.; Buck Louis, Germaine M.

    2007-01-01

    The secondary sex ratio is the ratio of male to female live births and historically has ranged from 102 to 106 males to 100 females. Temporal declines have been reported in many countries prompting authors to hypothesize an environmental etiology. Blood specimens were obtained from 99 women aged 24-34 prior to attempting pregnancy and quantified for 76 polychlorinated biphenyl (PCB) congeners using dual column gas chromatography with electron capture detection. Women were prospectively followed until pregnancy or 12 cycles of trying. The odds of a male birth for three PCB groupings (total, estrogenic, anti-estrogenic) controlling for maternal characteristics were estimated using logistic regression. Among the 50 women with live births and PCB data, 26 female and 24 male infants were born (ratio 0.92). After adjusting for age and body mass index, odds of a male birth were elevated among women in the second (OR=1.29) and third (OR=1.48) tertiles of estrogenic PCBs; odds (OR=0.70) were reduced among women in the highest tertile of anti-estrogenic PCBs. All confidence intervals included one. The direction of the odds ratios in this preliminary study varied by PCB groupings, supporting the need to study specific PCB patterns when assessing environmental influences on the secondary sex ratio

  13. 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 pprocesses 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. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Polychlorinated Biphenyls Water Pollution along the River Nile, Egypt

    Directory of Open Access Journals (Sweden)

    Ayman Mohamed Megahed

    2015-01-01

    Full Text Available Ten polychlorinated biphenyl (PCB congeners were determined in water samples collected along the River Nile using gas chromatography-electron capture detector (GC-ECD. PCB concentrations ranged from 14 to 20 μg/L, which were higher than those reported in previous studies, indicating serious PCB pollution in the River Nile. PCB congener profiles varied depending on the sampling sties. PCB-138 was the predominant congener accounting for more than 18% of total PCBs. The composition of PCB congeners in the water revealed that highly chlorinated PCB technical mixtures such as Aroclor 1254 was the main PCB production historically used in Egypt. An increasing trend in PCB levels from the upper stream to the Nile estuaries was observed. The calculated flux of PCBs indicated that 6.8 tons of PCBs is dumped into the Mediterranean Sea each year from the River Nile. The hazard quotients and carcinogenic risk caused by PCB pollution in the River Nile were above the acceptable level indicating that PCBs in the River Nile water pose adverse health effects for all age groups. Our findings revealed that PCBs possess a serious risk to the Egyptian population that depends mainly on the River Nile as a source of water. Thus, stricter legislation and regulatory controls should be applied to reduce the risk of PCBs in Egypt.

  15. Polychlorinated Biphenyls Water Pollution along the River Nile, Egypt.

    Science.gov (United States)

    Megahed, Ayman Mohamed; Dahshan, Hesham; Abd-El-Kader, Mahdy A; Abd-Elall, Amr Mohamed Mohamed; Elbana, Mariam Hassan; Nabawy, Ehab; Mahmoud, Hend A

    2015-01-01

    Ten polychlorinated biphenyl (PCB) congeners were determined in water samples collected along the River Nile using gas chromatography-electron capture detector (GC-ECD). PCB concentrations ranged from 14 to 20 μg/L, which were higher than those reported in previous studies, indicating serious PCB pollution in the River Nile. PCB congener profiles varied depending on the sampling sties. PCB-138 was the predominant congener accounting for more than 18% of total PCBs. The composition of PCB congeners in the water revealed that highly chlorinated PCB technical mixtures such as Aroclor 1254 was the main PCB production historically used in Egypt. An increasing trend in PCB levels from the upper stream to the Nile estuaries was observed. The calculated flux of PCBs indicated that 6.8 tons of PCBs is dumped into the Mediterranean Sea each year from the River Nile. The hazard quotients and carcinogenic risk caused by PCB pollution in the River Nile were above the acceptable level indicating that PCBs in the River Nile water pose adverse health effects for all age groups. Our findings revealed that PCBs possess a serious risk to the Egyptian population that depends mainly on the River Nile as a source of water. Thus, stricter legislation and regulatory controls should be applied to reduce the risk of PCBs in Egypt.

  16. Sex effect on polychlorinated biphenyl concentrations in fish: a synthesis

    Science.gov (United States)

    Madenjian, C.P.

    2011-01-01

    Polychlorinated biphenyls (PCBs) accumulate in fish primarily via food intake, and therefore, PCBs serve as a chemical tracer for food consumption. Sex differences in PCB concentrations of fish have been attributed to the following three mechanisms: (i) females losing a substantial portion of their PCB body burden during spawning and consequently their PCB concentration is considerably reduced immediately after spawning; (ii) sex differences in habitat utilization leading to sex differences in the PCB concentrations of the prey; and (iii) sex differences in gross growth efficiency, which is defined as growth divided by the amount of food consumption needed to achieve that growth. Based on my analyses and synthesis, mechanisms (i) and (ii) operate in relatively few fish populations, but can lead to mature males having PCB concentrations two to three times higher than mature female PCB concentrations. In contrast, mechanism (iii) operates in all fish populations, but typically, mechanism (iii) results in relatively modest sex differences, with mature males only between 15 and 35% higher in PCB concentration than mature females. In summary, the study of sex differences in PCB concentrations of fish has led to insights into fish behaviour and fish physiology.

  17. Binding properties of halogenated biphenyls to cells and macromolecules

    International Nuclear Information System (INIS)

    Pepe, M.G.

    1982-01-01

    The interaction of polychlorinated biphenyls (PCB) with serum proteins may help explain the cellular incorporation of PCB as the effect of PCB on thyroid hormone function. PCB reduces serum thyroxine and triiodothyronine levels in rats; the mechanism for this effect is unknown. The initial distribution of PCB from blood to tissue is rapid and depends on blood perfusion and tissue affinity; however, the translocation of unmetabolized PCB from its initial storage sites to adipose tissue may depend on serum and cellular protein interactions. Therefore, the ability of PCB to displace triiodothyronine binding to albumin and antibodies, as well as the effect of binding to serum proteins as a mechanism for cellular incorporation was measured. PCB binding to albumin showed both high and low affinity binding sites. This binding was able to prevent triiodothyronine binding to albumin. The distribution of PCB inserum showed that lipoproteins contained 94% of the total 14 C PCB added, while 5% of the 14 C PCB was bound to albumin. The in vitro binding of 14 C PCB to serum obtained from rats pretreated with PCB in their diets for 6 months showed a significant decrease (p 14 C PCB was higher (p < 0.05) in liver, adrenal and adipose cells than pituitary and thyroid cells

  18. Fate of polychlorinated biphenyls (PCBs) in anaerobic soils

    International Nuclear Information System (INIS)

    Murthy, N.B.K.

    1980-01-01

    Degradation of 14 C labelled 2,5,2; 2,5,2',5' PCBs was studied in Hagerstown silty clay loam with and without sludge amendments under anaerobic conditions for 42 days. Soil respiration was enhanced by PCBs in soil. PCBs reduced the soil respiration in soil with sludge. Volatilization of PCBs was decreased by sludge in soil. Most of the radioactivity was found in hexane extracts of soils. No further degradation products were observed. (author)

  19. Photochemical of Polychlorinated biphenyl by the photolysis and ...

    African Journals Online (AJOL)

    Michael Horsfall

    of 10% and 20% of total volume of solution of H2O2 were 88.8% and 93% respectively. The degradation of PCBs in terms of ratio to ethanol with oil transformer in 1:1, 2:1 and 3:1 was 83.4%, 92.5% and 93% respectively. The experiments show that UVC-photolysis of H2O2 leads to a degradation efficiency of PCBs in the ...

  20. Synthesis, radiosynthesis, in vitro and preliminary in vivo evaluation of biphenyl carboxylic and hydroxamic matrix metalloproteinase (MMP) inhibitors as potential tumor imaging agents

    International Nuclear Information System (INIS)

    Oltenfreiter, Ruth; Staelens, Ludovicus; Hillaert, Ulrik; Heremans, An; Noel, Agnes; Frankenne, Francis; Slegers, Guido

    2005-01-01

    Excess matrix degradation is one of the hallmarks of cancer and is an important factor in the process of tumor progression. It is implicated in invasion, metastasis, growth, angiogenesis and migration. Many characteristics of matrix metalloproteinases (MMPs) make them attractive therapeutic and diagnostic targets. MMP expression is upregulated at the tumor site, with localization of activity in the tumor or the surrounding stroma, providing a target for medical imaging techniques. Radioiodinated carboxylic and hydroxamic MMP inhibitors 2-(4'-[ 123 I] iodo-biphenyl-4-sulfonylamino)-3-methyl-butyric acid (9) and 2-(4'-[ 123 I] iodo-biphenyl-4-sulfonylamino)-3-methyl-butyramide (11), their unlabelled standards and precursors were synthesized. Radioiodination was conducted by electrophilic aromatic substitution of the tributylstannyl precursors and resulted in radiochemical yields of 70+/-5% (n=6) and 60+/-5% (n=4), respectively. In vitro zymography and enzyme assays showed for both hydroxamic acid and carboxylic acid compounds a good inhibition activity and a high selectivity for MMP-2. In vivo biodistribution in NMRI mice showed no long-term accumulation in organs and the possibility to accumulate in the tumor in a later phase of this study

  1. Synthesis, radiosynthesis, in vitro and preliminary in vivo evaluation of biphenyl carboxylic and hydroxamic matrix metalloproteinase (MMP) inhibitors as potential tumor imaging agents

    Energy Technology Data Exchange (ETDEWEB)

    Oltenfreiter, Ruth [Laboratory of Radiopharmacy, Ghent University, Harelbekestraat 72, 9000 Ghent (Belgium)]. E-mail: ruth.oltenfreiter@ugent.be; Staelens, Ludovicus [Laboratory of Radiopharmacy, Ghent University, Harelbekestraat 72, 9000 Ghent (Belgium); Hillaert, Ulrik [Laboratory for Medicinal Chemistry, Ghent University, Harelbekestraat 72, 9000 Ghent (Belgium); Heremans, An; Noel, Agnes [Laboratory of Tumor and Developmental Biology, University of Liege, Sart-Tilman, Liege (Belgium); Frankenne, Francis [Laboratory of Tumor and Developmental Biology, University of Liege, Sart-Tilman, Liege (Belgium); Slegers, Guido [Laboratory of Radiopharmacy, Ghent University, Harelbekestraat 72, 9000 Ghent (Belgium)

    2005-06-01

    Excess matrix degradation is one of the hallmarks of cancer and is an important factor in the process of tumor progression. It is implicated in invasion, metastasis, growth, angiogenesis and migration. Many characteristics of matrix metalloproteinases (MMPs) make them attractive therapeutic and diagnostic targets. MMP expression is upregulated at the tumor site, with localization of activity in the tumor or the surrounding stroma, providing a target for medical imaging techniques. Radioiodinated carboxylic and hydroxamic MMP inhibitors 2-(4'-[{sup 123}I] iodo-biphenyl-4-sulfonylamino)-3-methyl-butyric acid (9) and 2-(4'-[{sup 123}I] iodo-biphenyl-4-sulfonylamino)-3-methyl-butyramide (11), their unlabelled standards and precursors were synthesized. Radioiodination was conducted by electrophilic aromatic substitution of the tributylstannyl precursors and resulted in radiochemical yields of 70+/-5% (n=6) and 60+/-5% (n=4), respectively. In vitro zymography and enzyme assays showed for both hydroxamic acid and carboxylic acid compounds a good inhibition activity and a high selectivity for MMP-2. In vivo biodistribution in NMRI mice showed no long-term accumulation in organs and the possibility to accumulate in the tumor in a later phase of this study.

  2. Polychlorinated biphenyl quinone induces oxidative DNA damage and repair responses: The activations of NHEJ, BER and NER via ATM-p53 signaling axis

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Hui; Shi, Qiong; Song, Xiufang; Fu, Juanli; Hu, Lihua; Xu, Demei; Su, Chuanyang; Xia, Xiaomin; Song, Erqun; Song, Yang, E-mail: songyangwenrong@hotmail.com

    2015-07-01

    Our previous studies demonstrated that polychlorinated biphenyl (PCB) quinone induced oxidative DNA damage in HepG2 cells. To promote genomic integrity, DNA damage response (DDR) coordinates cell-cycle transitions, DNA repair and apoptosis. PCB quinone-induced cell cycle arrest and apoptosis have been documented, however, whether PCB quinone insult induce DNA repair signaling is still unknown. In this study, we identified the activation of DDR and corresponding signaling events in HepG2 cells upon the exposure to a synthetic PCB quinone, PCB29-pQ. Our data illustrated that PCB29-pQ induces the phosphorylation of p53, which was mediated by ataxia telangiectasia mutated (ATM) protein kinase. The observed phosphorylated histone H2AX (γ-H2AX) foci and the elevation of 8-hydroxy-2′-deoxyguanosine (8-OHdG) indicated that DDR was stimulated by PCB29-pQ treatment. Additionally, we found PCB29-pQ activates non-homologous end joining (NHEJ), base excision repair (BER) and nucleotide excision repair (NER) signalings. However, these repair pathways are not error-free processes and aberrant repair of DNA damage may cause the potential risk of carcinogenesis and mutagenesis. - Highlights: • Polychlorinated biphenyl quinone induces oxidative DNA damage in HepG2 cells. • The elevation of γ-H2AX and 8-OHdG indicates the activation of DNA damage response. • ATM-p53 signaling acts as the DNA damage sensor and effector. • Polychlorinated biphenyl quinone activates NHEJ, BER and NER signalings.

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

    Directory of Open Access Journals (Sweden)

    Huey Chong Kwong

    Full Text Available 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.

  4. Degradation of Chlorinated Aromatic Compounds in UASB Reactors

    DEFF Research Database (Denmark)

    Christiansen, Nina; Hendriksen, Hanne Vang; Järvinen, Kimmo T.

    1995-01-01

    Data on anaerobic degradation of chloroaromatic compounds in Upflow Anaerobic Sludge Blanket Reactors (UASB-reactor) are presented and compared. Special attention is given to the metabolic pathways for degradation of chlorinated phenols by granular sludge. Results indicate that PCP can be degraded...... in UASB-reactors via stepwise dechlorination to phenol. Phenol will subsequently be converted to benzoate before ring cleavage. Dechlorination proceeds via different pathways dependent upon the inocula used. Results are further presented on the design of special metabolic pathways in granules which do...

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

    International Nuclear Information System (INIS)

    Agudo, Antonio; Goni, Fernando; Etxeandia, Arsenio; Vives, Asuncion; Millan, Esmeralda; Lopez, Raul; Amiano, Pilar; Ardanaz, Eva; Barricarte, Aurelio; Dolores Chirlaque, M.; Dorronsoro, Miren; Jakszyn, Paula; Larranaga, Nerea; Martinez, Carmen; Navarro, Carmen; Rodriguez, Laudina

    2009-01-01

    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 μg/l); the corresponding figures for PCB 153 were 186 ng/g lipids and 1.25 μg/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.

  6. Striped bass stocks and concentrations of polychlorinated biphenyls

    Science.gov (United States)

    Fabrizio, Mary C.; Sloan, Ronald J.; O'Brien, John F.

    1991-01-01

    Harvest restrictions on striped bass Morone saxatilis fisheries in Atlantic coastal states were relaxed in 1990, but consistent, coastwide regulations of the harvest have been difficult to implement because of the mixed-stock nature of the fisheries and the recognized contamination of Hudson River fish by polychlorinated biphenyls (PCBs). We examined PCB concentrations and stock of origin of coastal striped bass to better understand the effects of these two factors on the composition of the harvest. The probability of observing differences in PCB concentration among fish from the Hudson River stock and the 'southern' group (Chesapeake Bay and Roanoke River stocks combined) was investigated with the logit model (a linear model for analysis of categorical data). Although total PCB concentrations were highly variable among fish from the two groups, striped bass classified as Hudson River stock had a significantly greater probability of having PCB concentrations equal to or greater than 2.00 mg/kg than did fish belonging to the southern group for all age- and size-classes examined. There was a significantly greater probability of observing total PCB concentrations equal to or exceeding 2.00 mg/kg in fish that were 5, 6, and 7 or more years old, and this probability increased linearly with age. We observed similar results when we examined the effect of size on total PCB concentration. The minimum-size limit estimated to permit escapement of fish to sustain stock production is 610 mm total length. Unless total PCB concentrations decrease in striped bass, it is likely that many harvestable fish will have concentrations that exceed the tolerance limit set by the U.S. Food and Drug Administration.

  7. 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.

  8. 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.

  9. 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.

  10. Microbial degradation of sulfamethoxazole in the environment.

    Science.gov (United States)

    Wang, Jianlong; Wang, Shizong

    2018-04-01

    Sulfamethoxazole (SMX) is one of the most widely applied sulfonamide antibiotics in the world, which is becoming a ubiquitous pollutant in the environment. In this mini-review, the microbial degradation of SMX was briefly reviewed. The performance of the conventional wastewater treatment plants in removing SMX was provided. The microorganisms capable of degrading SMX, including mixed cultures and pure cultures, were presented. The effects of environmental conditions such as temperature, pH, initial SMX concentration, and additional carbon sources on the biodegradation of SMX were discussed. The metabolic pathways of SMX degradation were summarized. Finally, the suggestions were made for further studies.

  11. Determination of selected polybrominated diphenylethers and polybrominated biphenyl in polymers by ultrasonic-assisted extraction and high-performance liquid chromatography-inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Mingwu, Shao; Chao, Wei; Yongjuan, Jia; Xinhua, Dai; Xiang, Fang

    2010-06-15

    A new method has been developed for the determination of selected polybrominated diphenylethers (PBDEs) and polybrominated biphenyl (PBB) in four polymers: high-density polyethylene (HDPE), polystyrene (PS), acrylonitrile-butadiene-styrene copolymer (ABS), and polypropylene (PP). PBDEs and PBB in the polymers were extracted with toluene, using ultrasonic-assisted extraction (UAE). The extracts were then determined by high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS), using external calibration (single-point). Extraction parameters of UAE and several ICP-MS parameters were optimized. Extraction efficiencies almost reached 100%. The relative standard deviations (RSDs) were in the range of 0.7%-5.4%. The results demonstrate that the method possesses advantages of good precision, as well as high extraction efficiency and accuracy. The method especially overcomes the problem of the thermal degradation of highly brominated PBDEs, such as PBDE-209.

  12. 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....

  13. Fast miniaturised sample preparation for the screening and comprehensive two-dimensional gas chromatographic determination of polychlorinated biphenyls in sludge

    NARCIS (Netherlands)

    Kristenson, E.M.; Neidig, H.C.; Vreuls, R.J.J.; Brinkman, U.A.T.

    2005-01-01

    Polychlorinated biphenyls (PCBs) in sludge are usually extracted by a technique such as Soxhlet with subsequent fractionation prior to long GC runs using GC-ECD or GC-HRMS. In this study, the extraction of selected chlorinated biphenyls (CBs) from a spiked sludge sample by three rapid techniques,

  14. Sulphonated biphenylated poly(aryl ether ketone)s for fuel cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Hu, W.; Jiang, Z. [Alan G. MacDiarmid Institute, Jilin University, Changchun 130012 (China); Robertson, G.P.; Guiver, M.D. [Institute for Chemical Process and Environmental Technology, National Research Council, Ottawa, Ontario K1A 0R6 (Canada); Kim, Y.S. [Electronic and Electrochemical Materials and Devices, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Liu, B.

    2010-02-15

    New series of fully aromatic poly(ether ketone)s with a biphenyl pendant groups were synthesised. A direct comparison of sulphonation reaction among monophenylated poly(ether ether ketone) (Ph-PEEK), biphenylated poly(ether ether ketone) (BiPh-PEEK) and PEEK (Victrex) was thoroughly investigated. Several advantages of the pendant-phenyl poly(ether ketone)s compared with commercial PEEK were identified, including ready control over the site of sulphonation and degree of sulphonation (DS), and mild and rapid sulphonation. The basic membrane physical properties comprising of thermal and mechanical properties, dimensional stability and proton conductivity were studied. One new membrane, sulphonated biphenylated poly(ether ether ketone) (BiPh-SPEEKDK) having a good combination of membrane properties was fabricated into a membrane electrode assembly (MEA), and it showed excellent direct methanol fuel cell (DMFC) performance. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  15. Case study of a non-destructive treatment method for the remediation of military structures containing polychlorinated biphenyl contaminated paint.

    Science.gov (United States)

    Saitta, Erin K H; Gittings, Michael J; Novaes-Card, Simone; Quinn, Jacqueline; Clausen, Christian; O'Hara, Suzanne; Yestrebsky, Cherie L

    2015-08-01

    Restricted by federal regulations and limited remediation options, buildings contaminated with paint laden with polychlorinated biphenyls (PCBs) have high costs associated with the disposal of hazardous materials. As opposed to current remediation methods which are often destructive and a risk to the surrounding environment, this study suggests a non-metal treatment system (NMTS) and a bimetallic treatment system (BTS) as versatile remediation options for painted industrial structures including concrete buildings, and metal machine parts. In this field study, four areas of a discontinued Department of Defense site were treated and monitored over 3 weeks. PCB levels in paint and treatment system samples were analyzed through gas chromatography/electron capture detection (GC-ECD). PCB concentrations were reduced by 95 percent on painted concrete and by 60-97 percent on painted metal with the majority of the PCB removal occurring within the first week of application. Post treatment laboratory studies including the utilization of an activated metal treatment system (AMTS) further degraded PCBs in BTS and NMTS by up to 82 percent and 99 percent, respectively, indicating that a two-step remediation option is viable. These findings demonstrate that the NMTS and BTS can be an effective, nondestructive, remediation process for large painted structures, allowing for the reuse or sale of remediated materials that otherwise may have been disposed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Organochlorine pesticides and polychlorinated biphenyls along an east-to-west gradient in subtropical North Atlantic surface water.

    Science.gov (United States)

    Lammel, Gerhard; Spitzy, Alejandro; Audy, Ondřej; Beckmann, Sabine; Codling, Garry P; Kretzschmann, Lisett; Kukučka, Petr; Stemmler, Irene

    2017-04-01

    Despite the fact that most persistent toxic substances have hardly been primarily emitted for several decades, their concentrations are only slowly decreasing in the global oceans. Surface seawater samples were collected along a 38°-24° N/28°-67° W transect in the subtropical North Atlantic Ocean. While the concentration levels of hexachlorobenzene (2.1-6.1 pg L -1 ), dichlorodiphenyltrichloroethane (DDT, up to 2.1 pg L -1 ) and polychlorinated biphenyls (PCB, 10.8-24.9 pg L -1 ) were in the same range as observed earlier in the North Atlantic, hexachlorocyclohexane (HCH, 90-627 pg L -1 ) was found elevated, partly also relative to previous measurements in the same sea region. Hereby, the ratio α-HCH/γ-HCH was very low, 0.09-0.13. Chlordane and endosulfan were found in the range pollution patterns in surface seawaters seem to be determined by atmospheric and oceanic transport patterns, rather than by mixing and air-sea equilibrium. The comparison with global multicompartment chemistry-transport model predictions of surface seawater levels indicate underestimated degradation of PCBs and overestimated emissions of endosulfan.

  17. Non-dioxin-like polychlorinated biphenyls (NDL-PCBs) in eel, trout, and barbel from the River Roya, Northern Italy.

    Science.gov (United States)

    Squadrone, S; Mignone, W; Abete, M C; Favaro, L; Scanzio, T; Foglini, C; Vivaldi, B; Prearo, M

    2015-05-15

    Non-dioxin-like polychlorinated biphenyls (NDL-PCBs) contribute to the dietary intake of total PCBs. They are consumed via ingestion of contaminated fish and fishery products. Thus, it is important to quantify their levels in aquatic organisms in order to evaluate the risks associated with fish consumption by humans. In 2013, an advisory against consumption of fish from the River Roya (IT) was disseminated after NDL PCBs were found to exceed maximum levels set by EU Regulations. We investigated the presence of NDL PCBs in eel, trout and barbel from the River Roya. We found concentrations in the range of 9.2-27.6 ng g(-)(1)ww in barbel, 9.2-97.0 ng g(-1)ww in trout and 9.0-239.5 ng g(-1)ww in eel. The distribution of congeners among different species did not show significant variations and was characterized by a higher proportion of 153, 138 and 180 congeners, according to their high resistance to metabolic degradation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Degradation of polycyclic aromatic hydrocarbons by a marine fluidized-bed enrichment

    International Nuclear Information System (INIS)

    Melin, E.S.; Puhakka, J.A.; Maennistoe, M.; Ferguson, J.F.

    1995-01-01

    Aerobic polycyclic aromatic hydrocarbon (PAH)-degrading bacteria from marine sediments were enriched and maintained in a fluidized-bed reactor (FBR). The FBR was continuously fed a mixture of naphthalene, biphenyl, 2-methylnaphthalene, 2,6-dimethylnaphthalene, acenaphthene, fluorene, and phenanthrene; and the effluent concentrations remained below 0.03 mg/L (detection limit) over a period of 6 months. In batch vial assays, the relative rates of PAH degradation were controlled by their solubilities and, in some cases, by their substitution patterns. The enrichment also degraded several other PAHs, including anthracene and pyrene. The results demonstrate that the predominant PAH constituents of coal-tar creosote can be degraded and that PAH-contaminated saline waters can be remediated by the marine enrichment

  19. A combination of Trastuzumab and 17-AAG induces enhanced ubiquitinylation and lysosomal pathway-dependent ErbB2 degradation and cytotoxicity in ErbB2-overexpressing breast cancer cells.

    Science.gov (United States)

    Raja, Srikumar M; Clubb, Robert J; Bhattacharyya, Mitra; Dimri, Manjari; Cheng, Hao; Pan, Wei; Ortega-Cava, Cesar; Lakku-Reddi, Alagarsamy; Naramura, Mayumi; Band, Vimla; Band, Hamid

    2008-10-01

    ErbB2 (or Her2/Neu) overexpression in breast cancer signifies poorer prognosis, yet it has provided an avenue for targeted therapy as demonstrated by the success of the humanized monoclonal antibody Trastuzumab (Herceptin). Resistance to Trastuzumab and eventual failure in most cases, however, necessitate alternate ErbB2-targeted therapies. HSP90 inhibitors such as 17-allylaminodemethoxygeldanamycin (17-AAG), potently downregulate the cell surface ErbB2. While the precise mechanisms of Trastuzumab or 17-AAG action remain unclear, ubiquitinylation-dependent proteasomal or lysosomal degradation of ErbB2 appears to play a substantial role. As Trastuzumab and 17-AAG induce the recruitment of distinct E3 ubiquitin ligases, Cbl and CHIP respectively, to ErbB2, we hypothesized that 17-AAG and Trastuzumab combination could induce a higher level of ubiquitinylation and downregulation of ErbB2 as compared to single drug treatments. We present biochemical and cell biological evidence that combined 17-AAG and Trastuzumab treatment of ErbB2-overexpressing breast cancer cell lines leads to enhanced ubiquitinylation, downregulation from the cell surface and lysosomal degradation of ErbB2. Importantly, combined 17-AAG and Trastuzumab treatment induced synergistic growth arrest and cell death specifically in ErbB2-overexpressing but not in ErbB2-low breast cancer cells. Our results suggest the 17-AAG and Trastuzumab combination as a mechanism-based combinatorial targeted therapy for ErbB2-overexpressing breast cancer patients.

  20. 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

  1. Foetal uptake of coplanar polychlorinated biphenyl (PCB) congeners in mice

    International Nuclear Information System (INIS)

    Darnerud, P.O.; Sinjari, T.; Joensson, C.J.

    1996-01-01

    Earlier studies have shown that the Ah-receptor binding polychlorinated biphenyl (PCB) congener 3,3',4,4'-tetrachlorobiphenyl (IUPAC number CB-77) accumulated as hydroxy and methylsulphone metabolites in late gestational mice foetuses. In the present paper the foetal accumulation potential in mice of other dioxin-like PCB congeners was studied: 3,3'4,4',4-pentachlorobiphenyl, 3,3'4,4'5,5'-hexachlorobiphenyl and 2,3,3',4,4'-pentachlorobiphenyl (IUPAC numbers CB-126, CB-169, CB-105, to some extent dioxin-like) were compared to results of CB-77 (all congeners 14 C-labelled and in equimolar doses (2.0 μmol/kg body wt.)). CB-77 resulted in the comparatively strongest foetal 14 C-accumulation, when measured in plasma or whole body homogenate four days after administration (day 17 of pregnancy); the plasma 14 C-values (calculated as pmol/g wet wt.) were 760, 130, 60 and 40 for CB-77, -126, 105 and -169, respectively, and the CB-77 derived radioactivity in the foetal compartment was 3.6% of administered dose (i.e. a considerable portion of the remaining maternal body radioactivity). Thin-layer chromatography (TLC) results, suggesting extensive CB-77 metabolism and foetal metabolite uptake, support earlier findings. The effects of CB-77 and CB-169 on foetal 7-ethoxyresorufin-O-deethylase (EROD) activities (day 17 of gestation; two days after 5 mg/kg body wt. dose (14.0-17.0 μmol/kg body wt.)) was about 20 times lower than of CB-126. In the dam, high radioactivity levels were observed int he liver and fat (highest concentrations found in CB-126 and CB-105, respectively). Strain comparison - foetal 14 C-uptake (four days after administration of CB-77) in C57BL mice was almost five times higher than in NMRI - may be correlated to earlier observed differences in EROD activities between these strains. The present results indicate that congener and strain differences exist regarding both foetal and maternal distribution patterns of coplanar PCB congeners and point out the

  2. Lactational transfer of mercury and polychlorinated biphenyls in polar bears.

    Science.gov (United States)

    Knott, Katrina K; Boyd, Daryle; Ylitalo, Gina M; O'Hara, Todd M

    2012-07-01

    We examined concentrations of total mercury (tHg, inorganic and methylated forms) and polychlorinated biphenyls (PCBs) in blood and milk from free-ranging Southern Beaufort-Chukchi Sea polar bears (Ursus maritimus) to assess maternal transfer of contaminants during lactation and the potential health risk to nursing young. Concentrations of contaminants in the blood of dependent and juvenile animals (ages 1-5 years) ranged from 35.9 to 52.2 μg kg(-1) ww for tHg and 13.9 to 52.2 μg kg(-1) ww (3255.81-11067.79 μg kg(-1) lw) for ΣPCB(7)s, similar to those of adult females, but greater than adult males. Contaminant concentrations in milk ranged from 5.7 to 71.8 μg tHg kg(-1)ww and 160 to 690 μg ΣPCB(11)s kg(-1) ww (547-5190 μg kg(-1) lw). The daily intake levels for tHg by milk consumption estimated for dependent young were below the tolerable daily intake level (TDIL) of tHg established for adult humans. Although the daily intake levels of PCBs through milk consumption for cubs of the year exceeded the TDIL thresholds, calculated dioxin equivalents for PCBs in milk were below adverse physiological thresholds for aquatic mammals. Relatively high concentrations of non-dioxin like PCBs in polar bear milk and blood could impact endocrine function of Southern Beaufort-Chukchi Sea polar bears, but this is uncertain. Transfer of contaminants during mid to late lactation likely limits bioaccumulation of dietary contaminants in female polar bears during spring. As polar bears respond to changes in their arctic sea ice habitat, the adverse health impacts associated with nutritional stress may be exacerbated by tHg and PCBs exposure, especially in ecologically and toxicologically sensitive polar bear cohorts such as reproductive females and young. Copyright © 2012. Published by Elsevier Ltd.

  3. Biphenyl-metabolizing bacteria in the rhizosphere of horseradish and bulk soil contaminated by polychlorinated biphenyls as revealed by stable isotope probing

    Czech Academy of Sciences Publication Activity Database

    Uhlík, Ondřej; Ječná, K.; Macková, M.; Vlček, Čestmír; Hroudová, Miluše; Demnerová, K.; Pačes, Václav; Macek, Tomáš

    2009-01-01

    Roč. 75, č. 20 (2009), s. 6471-6477 ISSN 0099-2240 R&D Projects: GA MŠk 2B08031 Grant - others:GA ČR(CZ) GA525/09/1058 Program:GA Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z50520514 Keywords : stable isotope probing * biphenyl * 16S rRNA gene * functional gene * remediation Subject RIV: EI - Biotechnology ; Bionics Impact factor: 3.686, year: 2009

  4. Anaerobic Degradation of Bicyclic Monoterpenes in Castellaniella defragrans

    Directory of Open Access Journals (Sweden)

    Edinson Puentes-Cala

    2018-02-01

    Full Text Available The microbial degradation pathways of bicyclic monoterpenes contain unknown enzymes for carbon–carbon cleavages. Such enzymes may also be present in the betaproteobacterium Castellaniella defragrans, a model organism to study the anaerobic monoterpene degradation. In this study, a deletion mutant strain missing the first enzyme of the monocyclic monoterpene pathway transformed cometabolically the bicyclics sabinene, 3-carene and α-pinene into several monocyclic monoterpenes and traces of cyclic monoterpene alcohols. Proteomes of cells grown on bicyclic monoterpenes resembled the proteomes of cells grown on monocyclic monoterpenes. Many transposon mutants unable to grow on bicyclic monoterpenes contained inactivated genes of the monocyclic monoterpene pathway. These observations suggest that the monocyclic degradation pathway is used to metabolize bicyclic monoterpenes. The initial step in the degradation is a decyclization (ring-opening reaction yielding monocyclic monoterpenes, which can be considered as a reverse reaction of the olefin cyclization of polyenes.

  5. Antioxidant compounds improved PCB-degradation by Burkholderia xenovorans strain LB400.

    Science.gov (United States)

    Ponce, Bernardita L; Latorre, Valeria K; González, Myriam; Seeger, Michael

    2011-12-10

    Polychlorobiphenyls (PCBs) are toxic and persistent organic pollutants that are widely distributed in the environment. Burkholderia xenovorans LB400 is capable of degrading aerobically an unusually wide range of PCBs. However, during PCB-degradation B. xenovorans LB400 generates reactive oxygen species (ROS) that affect its viability. The aim of this study was to increase the efficiency of PCB-degradation of B. xenovorans LB400 by adding antioxidant compounds that could increase tolerance to oxidative stress. The effect of antioxidant compounds on the growth, morphology and PCB-degradation by B. xenovorans LB400 was evaluated. α-Tocopherol or vitamin E (vitE) and berry extract (BE) increased slightly the growth of strain LB400 on biphenyl, whereas in presence of ascorbic acid or vitamin C (vitC) an inhibition of growth was observed. The growth of B. xenovorans LB400 in glucose was inhibited by the addition of 4-chlorobiphenyl (4-CB). Interestingly, in presence of α-tocopherol the growth of strain LB400 was less affected by 4-CB. By transmission electronic microscopy it was observed that α-tocopherol preserved the cell membranes and improved cell integrity of glucose-grown LB400 cells exposed to 4-CB, suggesting a protective effect of α-tocopherol. Notably, α-tocopherol increased biphenyl and 4-CB degradation by B. xenovorans LB400 in an aqueous solution. The effect of antioxidants compounds on PCB-bioremediation was evaluated in agricultural soil spiked with 2-chlorobiphenyl (2-CB), 4-CB and 2,4'-chlorobiphenyl (2,4'-CB). For bioaugmentation, LB400 cells grown on biphenyl and subsequently incubated with pyruvate were added to the soil. Native soil microbiota was able to remove PCBs. Bioaugmentation with strain LB400 increased strongly the PCB-degradation rate. Bioaugmentation with strain LB400 and biostimulation with α-tocopherol or berry extract increased further the PCB degradation. Half-life of 2,4'-CB decreased by bioaugmentation from 24 days to 4 days

  6. Bacterial Degradation of Aromatic Compounds

    Directory of Open Access Journals (Sweden)

    Qing X. Li

    2009-01-01

    Full Text Available Aromatic compounds are among the most prevalent and persistent pollutants in the environment. Petroleum-contaminated soil and sediment commonly contain a mixture of polycyclic aromatic hydrocarbons (PAHs and heterocyclic aromatics. Aromatics derived from industrial activities often have functional groups such as alkyls, halogens and nitro groups. Biodegradation is a major mechanism of removal of organic pollutants from a contaminated site. This review focuses on bacterial degradation pathways of selected aromatic compounds. Catabolic pathways of naphthalene, fluorene, phenanthrene, fluoranthene, pyrene, and benzo[a]pyrene are described in detail. Bacterial catabolism of the heterocycles dibenzofuran, carbazole, dibenzothiophene, and dibenzodioxin is discussed. Bacterial catabolism of alkylated PAHs is summarized, followed by a brief discussion of proteomics and metabolomics as powerful tools for elucidation of biodegradation mechanisms.

  7. Assessment of the polychlorinated biphenyls (PCBs) levels in soil samples near an electric capacitor manufacturing industry in Morelos, Mexico.

    Science.gov (United States)

    Perez-Maldonado, Ivan N; Salazar, Rogelio Costilla; Ilizaliturri-Hernandez, Cesar A; Espinosa-Reyes, Guillermo; Perez-Vazquez, Francisco J; Fernandez-Macias, Juan C

    2014-09-19

    In Mexico, polychlorinated biphenyls (PCBs) were principally used as heat transfer chemicals in electric transformers and capacitors as well as hydraulic fluids and lubricants in heavy electrical equipment since the early 1940s. However, although PCBs have been banned in Mexico, their past and present improper disposal has resulted in environmental contamination. Therefore, the aim of this study was to evaluate the PCBs levels in soil samples in the immediate area of an electric capacitor manufacturing industry, which was established several years ago in Alpuyeca, Morelos, Mexico. To confirm the presence of PCBs, surface soil samples (1-5 cm in depth) were collected from the vicinity of the industry. We determined the concentrations of 40 PCB congeners in soil samples using gas chromatography/mass spectrometry. The total PCBs levels in the soil samples ranged from 6.2 to 108460.6 μg kg(-1). Moreover, when we analyzed the results of the congeners (non-dioxin-like PCBs and dioxin-like PCBs), the levels of non-dioxin-like PCB congeners ranged from 5.7 to 103469 μg kg(-1) and the levels of dioxin-like PCB congeners ranged from 0.5 to 4992 μg kg(-1). Considering that soil is an important pathway of exposure in humans, analysis of PCBs levels in blood (as a biomarker of exposure) is necessary in individuals living in Alpuyeca, Morelos.

  8. Differential bioavailability of polychlorinated biphenyls associated with environmental particles: Microplastic in comparison to wood, coal and biochar.

    Science.gov (United States)

    Beckingham, B; Ghosh, U

    2017-01-01

    Microplastic particles are increasingly being discovered in diverse habitats and a host of species are found to ingest them. Since plastics are known to sorb hydrophobic organic contaminants (HOCs) there is a question of what risk of chemical exposure is posed to aquatic biota from microplastic-associated contaminants. We investigate bioavailability of polychlorinated biphenyls (PCBs) from polypropylene microplastic by measuring solid-water distribution coefficients, gut fluid solubilization, and bioaccumulation using sediment invertebrate worms as a test system. Microplastic-associated PCBs are placed in a differential bioavailability framework by comparing the results to several other natural and anthrogenic particles, including wood, coal, and biochar. PCB distribution coefficients for polypropylene were higher than natural organic materials like wood, but in the range of lipids and sediment organic carbon, and smaller than black carbons like coal and biochars. Gut fluid solubilization potential increased in the order: coal microplastics in sediments had an overall impact of reducing bioavailability and transfer of HOCs to sediment-ingesting organisms. Since the vast majority of sediment and suspended particles in the environment are natural organic and inorganic materials, pollutant transfer through particle ingestion will be dominated by these particles and not microplastics. Therefore, these results support the conclusion that in most cases the transfer of organic pollutants to aquatic organisms from microplastic in the diet is likely a small contribution compared to other natural pathways of exposure. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Chemometric comparison of polychlorinated biphenyl residues and toxicologically active polychlorinated biphenyl congeners in the eggs of Forster's Terns (Sterna fosteri)

    Science.gov (United States)

    Schwartz, Ted R.; Stalling, David L.

    1991-01-01

    The separation and characterization of complex mixtures of polychlorinated biphenyls (PCBs) is approached from the perspective of a problem in chemometrics. A technique for quantitative determination of PCB congeners is described as well as an enrichment technique designed to isolate only those congener residues which induce mixed aryl hydrocarbon hydroxylase enzyme activity. A congener-specific procedure is utilized for the determination of PCBs in whichn-alkyl trichloroacetates are used as retention index marker compounds. Retention indices are reproducible in the range of ±0.05 to ±0.7 depending on the specific congener. A laboratory data base system developed to aid in the editing and quantitation of data generated from capillary gas chromatography was employed to quantitate chromatographic data. Data base management was provided by computer programs written in VAX-DSM (Digital Standard MUMPS) for the VAX-DEC (Digital Equipment Corp.) family of computers.In the chemometric evaluation of these complex chromatographic profiles, data are viewed from a single analysis as a point in multi-dimensional space. Principal Components Analysis was used to obtain a representation of the data in a lower dimensional space. Two-and three-dimensional proections based on sample scores from the principal components models were used to visualize the behavior of Aroclor® mixtures. These models can be used to determine if new sample profiles may be represented by Aroclor profiles. Concentrations of individual congeners of a given chlorine substitution may be summed to form homologue concentration. However, the use of homologue concentrations in classification studies with environmental samples can lead to erroneous conclusions about sample similarity. Chemometric applications are discussed for evaluation of Aroclor mixture analysis and compositional description of environmental residues of PCBs in eggs of Forster's terns (Sterna fosteri) collected from colonies near Lake Poygan

  10. Intensification of the aerobic bioremediation of an actual site soil historically contaminated by polychlorinated biphenyls (PCBs through bioaugmentation with a non acclimated, complex source of microorganisms

    Directory of Open Access Journals (Sweden)

    Fava Fabio

    2006-03-01

    Full Text Available Abstract Background The biotreatability of actual-site polychlorinated biphenyl (PCB-contaminated soils is often limited by their poor content of autochthonous pollutant-degrading microorganisms. In such cases, inoculation might be the solution for a successful bioremediation. Some pure and mixed cultures of characterized PCB degrading bacteria have been tested to this purpose. However, several failures have been recorded mostly due to the inability of inoculated microbes to compete with autochthonous microflora and to face the toxicity and the scarcity of nutrients occurring in the contaminated biotope. Complex microbial systems, such as compost or sludge, normally consisting of a large variety of robust microorganisms and essential nutrients, would have better chances to succeed in colonizing degraded contaminated soils. However, such sources of microorganisms have been poorly applied in soil bioremediation and in particular in the biotreatment of soil with PCBs. Thus, in this study the effects of Enzyveba, i.e. a consortium of non-adapted microorganisms developed from composted material, on the slurry- and solid-phase aerobic bioremediation of an actual-site, aged PCB-contaminated soil were studied. Results A slow and only partial biodegradation of low-chlorinated biphenyls, along with a moderate depletion of initial soil ecotoxicity, were observed in the not-inoculated reactors. Enzyveba significantly increased the availability and the persistence of aerobic PCB- and chlorobenzoic acid-degrading cultivable bacteria in the bioreactors, in particular during the earlier phase of treatment. It also markedly enhanced PCB-biodegradation rate and extent (from 50 to 100% as well as the final soil detoxification, in particular under slurry-phase conditions. Taken together, data obtained suggest that Enzyveba enhanced the biotreatability of the selected soil by providing exogenous bacteria and fungi able to remove inhibitory or toxic intermediates of

  11. Neurological condition in 18-month-old children perinatally exposed to polychlorinated biphenyls and dioxins

    NARCIS (Netherlands)

    Huisman, M; KoopmanEsseboom, C; vanderPaauw, CG; Tuinstra, LGMT; Fidler, [No Value; WeisglasKuperus, N; Sauer, PJJ; Boersma, ER; Touwen, BCL

    1995-01-01

    The neurological optimality of 418 Dutch children was evaluated at the age of 18 months, in order to determine whether prenatal and breast milk mediated exposure to polychlorinated biphenyls (PCBs) and dioxins affected neurological development, Half of the infants were breast-fed, the other half

  12. The effect of the structure of polychlorinated biphenyls on their hydroxylation, oxidation, and glutathionyl conjugation reactions.

    Science.gov (United States)

    Song, Er Qun; Ma, Xiao Yan; Tian, Xing Guo; Liu, Jing; Liu, Li Chao; Dong, Hui; Song, Yang

    2013-02-01

    To compare the nature of the metabolites formed from the phase I metabolism (hydroxylation and oxidation) and phase II metabolism (glutathionyl conjugation) of PCBs that have different chlorine substitution patterns. To discuss the structure-activity relationships and metabolic mechanisms of PCBs. 4-Cl-biphenyl (PCB3), 4,4'-Cl-biphenyl (PCB15), 3,4,3',4'-Cl-biphenyl (PCB77) were used for in vitro metabolic study. LC/MS and UV-Vis studies were performed for metabolites identification. The cytochrome P-450 catalyzed hydroxylation rate decreased as the number of chlorine substitutions increased. In this reaction, PCB3 was fully metabolized, approximately half of the PCB15 was metabolized and PCB77 was not metabolized at all. The oxidation rate of PCB15-HQ was higher than that of PCB3-HQ under various oxidation conditions. The LC/MS and UV-Vis data suggest that in the conjugation reaction of PCB15-Q and GSH, the Michael addition reaction occurs preferentially over the displacement reaction. The metabolic profiles of polychlorinated biphenyls (PCBs) are dramatically affected by chlorine substitution patterns. It is suggested that the metabolic profiles of PCBs are related to their chlorine substitution patterns, which may have implications for the toxicity of PCB exposure. Copyright © 2013 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

  13. Allee effect in polar bears: A potential consequence of polychlorinated biphenyl contamination.

    Czech Academy of Sciences Publication Activity Database

    Pavlová, Viola; Nabe-Nielsen, J.; Dietz, R.; Sonne, C.; Grimm, V.

    2016-01-01

    Roč. 283, č. 1843 (2016), č. článku 20161883. ISSN 0962-8452 Institutional support: RVO:60077344 Keywords : allee effect * polychlorinated biphenyls * polar bear s * male reproduction Subject RIV: EH - Ecology, Behaviour Impact factor: 4.940, year: 2016

  14. POLYCHLORINATED BIPHENYL MIXTURES (AROCLORS) INHIBIT LPS-INDUCED MURINE SPLENOCYTE PROLIFERATION IN VITRO. (R826687)

    Science.gov (United States)

    AbstractThe immune system is believed to be a sensitive indicator for adverse polychlorinated biphenyl (PCB)-induced health effects. Four commercial PCB mixtures (Aroclors) or six individual PCB congeners were evaluated for their effect on splenocyte viability and lip...

  15. PERINATAL EXPOSURE TO POLYCHLORINATED-BIPHENYLS AND DIOXINS THROUGH DIETARY-INTAKE

    NARCIS (Netherlands)

    HUISMAN, M; EERENSTEIN, SEJ; KOOPMANESSEBOOM, C; BROUWER, M; FIDLER, [No Value; MUSKIET, FAJ; SAUER, PJJ; BOERSMA, ER

    1995-01-01

    Polychlorinated biphenyls (PCBs) and dioxins (polychlorinated dibenzo-p-dioxins and dibenzofurans) are potentially hazardous compounds. Since food is the major source (> 90%) for the accumulation of PCBs and dioxins in the human body, food habits in women determine the degree of fetal exposure and

  16. Contamination of free-range chicken eggs with dioxins and dioxin-like polychlorinated biphenyls

    NARCIS (Netherlands)

    Schoeters, G.; Hoogenboom, L.A.P.

    2006-01-01

    Dioxins and dioxin-like (DL) polychlorinated biphenyls (PCB) are persistent organic pollutants that enter the body mainly by food intake. A small margin exists between current exposure levels in the human population and the levels causing biological effects. Therefore, stringent control of

  17. [Determination of biphenyl ether herbicides in water using HPLC with cloud-point extraction].

    Science.gov (United States)

    He, Cheng-Yan; Li, Yuan-Qian; Wang, Shen-Jiao; Ouyang, Hua-Xue; Zheng, Bo

    2010-01-01

    To determine residues of multiple biphenyl ether herbicides simultaneously in water using high performance liquid chromatography (HPLC) with cloud-point extraction. The residues of eight biphenyl ether herbicides (including bentazone, fomesafen, acifluorfen, aclonifen, bifenox, fluoroglycofenethy, nitrofen, oxyfluorfen) in water samples were extracted with cloud-point extraction of Triton X-114. The analytes were separated and determined using reverse phase HPLC with ultraviolet detector at 300 nm. Optimized conditions for the pretreatment of water samples and the parameters of chromatographic separation applied. There was a good linear correlation between the concentration and the peak area of the analytes in the range of 0.05-2.00 mg/L (r = 0.9991-0.9998). Except bentazone, the spiked recoveries of the biphenyl ether herbicides in the water samples ranged from 80.1% to 100.9%, with relative standard deviations ranging from 2.70% to 6.40%. The detection limit of the method ranged from 0.10 microg/L to 0.50 microg/L. The proposed method is simple, rapid and sensitive, and can meet the requirements of determination of multiple biphenyl ether herbicides simultaneously in natural waters.

  18. Self-assembly of aromatic-derivatized amphiphiles: Phenyl, biphenyl, and terphenyl fatty acids and phospholipids

    Energy Technology Data Exchange (ETDEWEB)

    Geiger, H.C.; Perlstein, J.; Lachicotte, R.J.; Wyrozebski, K.; Whitten, D.G. [Univ. of Rochester, NY (United States)]|[Los Alamos National Lab., NM (United States). Chemical Science and Technology Div.

    1999-08-17

    This paper reports the synthesis of a series of amphiphiles (fatty acids and phosphatidylcholine derivatives) containing phenyl, biphenyl, and terphenyl chromophores inserted in the hydrocarbon chain and a study of their self-assembly in Langmuir-Blodgett films and aqueous dispersions. As observed and reported earlier for amphiphiles containing trans-stilbene, styrylthiophene, or azobenzene chromophores, several of the biphenyl and terphenyl derivatives show strong evidence of ground state association to form H aggregates characterized by a blue shift in absorption and a structured, red-shifted fluorescence. The phenyl amphiphiles show different behavior, suggesting that, even for pure films or bilayers, there is very little or no ground state association. For the biphenyl and terphenyl phospholipids, aqueous suspensions obtained by sonication are closed bilayer vesicles similar in size to those formed from the corresponding saturated phospholipids. The overall results of the present study indicate that biphenyl and terphenyl amphiphiles undergo aggregation processes to form compact arrays formally similar to those observed with stilbenen tolan, azobenzene, and squaraine derivatives but that the aromatic-aromatic interactions are considerably weaker than those for the more extended aromatics and lead to less distortion of the assembly structure.

  19. 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...

  20. Polychlorinated biphenyl-induced alterations of thyroid hormone homeostasis and brain development in the rat

    NARCIS (Netherlands)

    Morse, D.C.

    1995-01-01

    Introduction

    The 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

  1. 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...

  2. 4,4′-Bis(2,2-diphenylvinyl-1,1′-biphenyl

    Directory of Open Access Journals (Sweden)

    Yun-Feng Li

    2011-01-01

    Full Text Available The title molecule, C40H30, lies on an inversion center. The two unique phenyl rings form dihedral angles of 51.98 (8 and 67.58 (8° with the essentially planar biphenyl unit [maximum deviation = 0.0360 (14 Å].

  3. Plasma-chemical technology of treatment of halogen-containing waste including polychlorinated biphenyls

    Science.gov (United States)

    Gusarov, E. E.; Malkov, Yu. P.; Stepanov, S. G.; Troshchinenko, G. A.; Zasypkin, I. M.

    2010-12-01

    We consider the developed plasma-chemical technology of halogen-containing substances treatment. The paper contains the experimental plant schematic and the positive results obtained after the treatment of tetrafluoromethane, ozone-damaging freon 12, polychlorinated biphenyls (PCB), the waste containing fluoride and chloride organics. The technology is proposed for industrial application.

  4. 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,...

  5. A luminal flavoprotein in endoplasmic reticulum-associated degradation

    DEFF Research Database (Denmark)

    Riemer, Jan; Appenzeller-Herzog, Christian; Johansson, Linda

    2009-01-01

    The quality control system of the endoplasmic reticulum (ER) discriminates between native and nonnative proteins. The latter are degraded by the ER-associated degradation (ERAD) pathway. Whereas many cytosolic and membrane components of this system are known, only few luminal players have been id...

  6. Microbial consortia involved in the anaerobic degradation of hydrocarbons.

    Science.gov (United States)

    Zwolinski; Harris, R F; Hickey, W J

    2000-01-01

    In this review, we examine the energetics of well-characterized biodegradation pathways and explore the possibilities for these to support growth of multiple organisms interacting in consortia. The relevant phenotypic and/or phylogenetic characteristics of isolates and consortia mediating hydrocarbon degradation coupled with different terminal electron-accepting processes (TEAP) are also reviewed. While the information on metabolic pathways has been gained from the analysis of individual isolates, the energetic framework presented here demonstrates that microbial consortia could be readily postulated for hydrocarbon degradation coupled to any TEAP. Several specialized reactions occur within these pathways, and the organisms mediating these are likely to play a key role in defining the hydrocarbon degradation characteristics of the community under a given TEAP. Comparing these processes within and between TEAPs reveals biological unity in that divergent phylotypes display similar degradation mechanisms and biological diversity in that hydrocarbon-degraders closely related as phylotypes differ in the type and variety of hydrocarbon degradation pathways they possess. Analysis of microcosms and of field samples suggests that we have only begun to reveal the diversity of organisms mediating anaerobic hydrocarbon degradation. Advancements in the understanding of how hydrocarbon-degrading communities function will be significantly affected by the extent to which organisms mediating specialized reactions can be identified, and tools developed to allow their study in situ.

  7. PEM fuel cell degradation

    Energy Technology Data Exchange (ETDEWEB)

    Borup, Rodney L [Los Alamos National Laboratory; Mukundan, Rangachary [Los Alamos National Laboratory

    2010-01-01

    The durability of PEM fuel cells is a major barrier to the commercialization of these systems for stationary and transportation power applications. While significant progress has been made in understanding degradation mechanisms and improving materials, further improvements in durability are required to meet commercialization targets. Catalyst and electrode durability remains a primary degradation mode, with much work reported on understanding how the catalyst and electrode structure degrades. Accelerated Stress Tests (ASTs) are used to rapidly evaluate component degradation, however the results are sometimes easy, and other times difficult to correlate. Tests that were developed to accelerate degradation of single components are shown to also affect other component's degradation modes. Non-ideal examples of this include ASTs examining catalyst degradation performances losses due to catalyst degradation do not always well correlate with catalyst surface area and also lead to losses in mass transport.

  8. 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

  9. Bioaccumulation of hydroxylated polychlorinated biphenyls and pentachlorophenol in the serum of northern elephant seal pups (Mirounga angustirostris)

    International Nuclear Information System (INIS)

    Louis, Caroline; Covaci, Adrian; Stas, Marie; Crocker, Daniel E.; Malarvannan, Govindan; Dirtu, Alin C.; Debier, Cathy

    2015-01-01

    Northern elephant seals (NES) (Mirounga angustirostris) from the Año Nuevo State Reserve (CA, USA) were sampled at 1-, 4-, 7- and 10-week post-weaning. Concentrations of hydroxylated polychlorinated biphenyls (HO-PCBs) and their parent PCBs were measured in the serum of each individual. The ΣHO-PCB concentrations in the serum increased significantly between early and late fast (from 282±20 to 529±31 pg/mL). This increase might result from a mobilisation of HO-PCBs transferred from the mother during gestation and/or lactation and stored in the pup's liver. Food deprivation has been shown to exacerbate biotransformation capacities in mammals, birds and fish. The HO-penta-CBs was the predominant homologue group, followed by HO-hexa-CBs and HO-hepta-CBs. No preferential pathway for the metabolism of HO-PCBs (HO-direct insertion or NIH-shift of a chlorine atom) could be evidenced. The concentrations of pentachlorophenol (PCP) in the serum of weaned NES increased from 103±7 pg/mL at early fast to 246±41 pg/mL at late fast, which is within the range of PCP concentrations usually encountered in marine mammals. - Highlights: • Σ HO-PCB concentrations in serum significantly increased between early and late fast. • The HO-penta-CBs were the predominant homologue group measured in serum. • No preferential pathway for the metabolism of HO-PCBs could be evidenced. • PCP concentrations in serum significantly increased between early and late fast

  10. Bioaccumulation of hydroxylated polychlorinated biphenyls and pentachlorophenol in the serum of northern elephant seal pups (Mirounga angustirostris)

    Energy Technology Data Exchange (ETDEWEB)

    Louis, Caroline, E-mail: caroline.louis@uclouvain.be [Institut des Sciences de la Vie, UCLouvain, Croix du Sud 2/L7.05.08, 1348 Louvain-la-Neuve (Belgium); Covaci, Adrian [Department of Pharmaceutical Sciences, Toxicological Center, Campus Drie Eiken, Universiteit Antwerpen, Universiteitsplein 1, 2610 Wilrijk (Belgium); Stas, Marie [Institut des Sciences de la Vie, UCLouvain, Croix du Sud 2/L7.05.08, 1348 Louvain-la-Neuve (Belgium); Crocker, Daniel E. [Department of Biology, Sonoma State University, 1801 East Cotati Ave, Rohnert Park, CA 94928 (United States); Malarvannan, Govindan [Department of Pharmaceutical Sciences, Toxicological Center, Campus Drie Eiken, Universiteit Antwerpen, Universiteitsplein 1, 2610 Wilrijk (Belgium); Dirtu, Alin C. [Department of Pharmaceutical Sciences, Toxicological Center, Campus Drie Eiken, Universiteit Antwerpen, Universiteitsplein 1, 2610 Wilrijk (Belgium); Department of Chemistry, “Al. I. Cuza” University of Iasi, 700506 Iasi (Romania); Debier, Cathy [Institut des Sciences de la Vie, UCLouvain, Croix du Sud 2/L7.05.08, 1348 Louvain-la-Neuve (Belgium)

    2015-01-15

    Northern elephant seals (NES) (Mirounga angustirostris) from the Año Nuevo State Reserve (CA, USA) were sampled at 1-, 4-, 7- and 10-week post-weaning. Concentrations of hydroxylated polychlorinated biphenyls (HO-PCBs) and their parent PCBs were measured in the serum of each individual. The ΣHO-PCB concentrations in the serum increased significantly between early and late fast (from 282±20 to 529±31 pg/mL). This increase might result from a mobilisation of HO-PCBs transferred from the mother during gestation and/or lactation and stored in the pup's liver. Food deprivation has been shown to exacerbate biotransformation capacities in mammals, birds and fish. The HO-penta-CBs was the predominant homologue group, followed by HO-hexa-CBs and HO-hepta-CBs. No preferential pathway for the metabolism of HO-PCBs (HO-direct insertion or NIH-shift of a chlorine atom) could be evidenced. The concentrations of pentachlorophenol (PCP) in the serum of weaned NES increased from 103±7 pg/mL at early fast to 246±41 pg/mL at late fast, which is within the range of PCP concentrations usually encountered in marine mammals. - Highlights: • Σ HO-PCB concentrations in serum significantly increased between early and late fast. • The HO-penta-CBs were the predominant homologue group measured in serum. • No preferential pathway for the metabolism of HO-PCBs could be evidenced. • PCP concentrations in serum significantly increased between early and late fast.

  11. Targeting proteins for degradation.

    Science.gov (United States)

    Schrader, Erin K; Harstad, Kristine G; Matouschek, Andreas

    2009-11-01

    Protein degradation plays a central role in many cellular functions. Misfolded and damaged proteins are removed from the cell to avoid toxicity. The concentrations of regulatory proteins are adjusted by degradation at the appropriate time. Both foreign and native proteins are digested into small peptides as part of the adaptive immune response. In eukaryotic cells, an ATP-dependent protease called the proteasome is responsible for much of this proteolysis. Proteins are targeted for proteasomal degradation by a two-part degron, which consists of a proteasome binding signal and a degradation initiation site. Here we describe how both components contribute to the specificity of degradation.

  12. Structure selectivity in degradation and translocation of polychlorinated biphenyls (Delor 103) with a Pleurotus ostreatus (oyster mushroom) culture

    Czech Academy of Sciences Publication Activity Database

    Moeder, M.; Cajthaml, Tomáš; Koeller, G.; Erbanová, Pavla; Šašek, Václav

    2005-01-01

    Roč. 61, - (2005), s. 1370-1378 ISSN 0045-6535 R&D Projects: GA MŠk LN00B030 Institutional research plan: CEZ:AV0Z5020903 Keywords : PCB * pleurotus ostreatus * biodegradation Subject RIV: EE - Microbiology, Virology Impact factor: 2.297, year: 2005

  13. Biological Pathways

    Science.gov (United States)

    Skip to main content Biological Pathways Fact Sheet Enter Search Term(s): Español Research Funding An Overview Bioinformatics Current Grants Education and Training Funding Extramural Research News Features ...

  14. Congener specific distribution and health risk assessment of polychlorinated biphenyls in urban soils

    Directory of Open Access Journals (Sweden)

    Bhupander Kumar

    2012-10-01

    Full Text Available 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 environmental pollutants, with cumulative effects of long-range atmospheric transport and local sources. Around the world, comparatively higher concentrations of PCBs have been reported in urban soils than suburban or rural soils. Higher amount of PCBs in urban soils may cause toxicological health risks to urban residents through ingestion, inhalation and skin contact. This paper presents the PCB distribution in soils from Delhi, India, and exposure risk estimates for human health through soil ingestion. The concentration of ΣPCBs ranged between 1.08-100.67 ng g–1 (mean 21.16 ng g–1±5.24 ng g–1, which was much lower than the Canadian soil quality guideline value of 1.3 mg/kg or 1300 ng g–1. Human health risk estimates through the soil ingestion pathway were made in terms of lifetime average daily dose (LADD, incremental lifetime cancer risks and non-carcinogenic hazard quotient (HQ. The LADD for Delhi adults and children was 3.02x10–8 mg kg–1 d–1 and 1.57x10–7 mg kg–1 d–1, respectively, which corresponds to toxic equivalent quotients (TEQ intake of 0.105 pg TEQ kg–1 d–1 (0.735 pg TEQ kg–1 week–1 and 0.543 pg TEQ kg–1 d–1 (3.801 pg TEQ kg–1 week–1, respectively. The estimated LADD for Delhi residents was lower than the acceptable

  15. Novel metabolic pathways in Archaea.

    Science.gov (United States)

    Sato, Takaaki; Atomi, Haruyuki

    2011-06-01

    The Archaea harbor many metabolic pathways that differ to previously recognized classical pathways. Glycolysis is carried out by modified versions of the Embden-Meyerhof and Entner-Doudoroff pathways. Thermophilic archaea have recently been found to harbor a bi-functional fructose-1,6-bisphosphate aldolase/phosphatase for gluconeogenesis. A number of novel pentose-degrading pathways have also been recently identified. In terms of anabolic metabolism, a pathway for acetate assimilation, the methylaspartate cycle, and two CO2-fixing pathways, the 3-hydroxypropionate/4-hydroxybutyrate cycle and the dicarboxylate/4-hydroxybutyrate cycle, have been elucidated. As for biosynthetic pathways, recent studies have clarified the enzymes responsible for several steps involved in the biosynthesis of inositol phospholipids, polyamine, coenzyme A, flavin adeninedinucleotide and heme. By examining the presence/absence of homologs of these enzymes on genome sequences, we have found that the majority of these enzymes and pathways are specific to the Archaea. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Evaluating Chemical Reactivity And Mechanical Stability Of Nano Palladized Iron Embedded In Activated Carbon On Dechlorination Of Polychlorinated Biphenyls

    Science.gov (United States)

    Remediation of contaminated sites with hydrophobic organic compounds such as polychlorinated biphenyls (PCBs) remains a scientific and technical challenge. The high stability, low aqueous solubility, and high organic affinity of PCBs make them difficult to treat. Many physical,...

  17. 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...

  18. Gender-related decrease in raven`s progressive matrices scores in children prenatally exposed to polychlorinated biphenyls and related contaminants

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Y.L.; Lai, T.J.; Chen, S.J.; Hsu, C.C. [National Cheng Kung Univ. Medical College, Taiwan (China)

    1995-07-01

    Polychlorinated biphenyls (PCBs) and industrial mixtures that have been widely used throughout the world. PCBs have long environmental half lives and bioconcentrate, therefore contaminating soil, water, wild life, and human tissues. Typical human exposures come from environmental contamination of food supply, especially fresh water fish and meat, and occupational exposures. In certain uses, PCBs can partially oxidize and themselves become contaminated by extremely toxic compounds such as polychlorinated dibenzofurans (PCDFs). Two episodes of intoxication with heat-degraded PCBs have occurred, in Japan and Taiwan respectively. In 1979, over 2000 persons in Taiwan were intoxicated by heat-degraded PCBs that had contaminated their cooking oil. Kaneclor 500 (a Japanese PCB mixture) contained in the heating pipe was used as the heat transmitter. Leakage of the pipe introduced PCBs and heat-degraded products such as polychlorinated dibenzofurans (PCDFs) and polychlorinated quaterphenyls (PCQs) into the rice oil. Exposed victims developed chloracne, hyperpigmentation, peripheral neuropathy, and other signs and symptoms which were later called Yu-Cheng ({open_quotes}oil disease{close_quotes}) in Taiwan. These symptoms were caused not only by PCBs but by their heat degraded products, PCDFs. PCBs, PCDFs and PCDDs also can cross the placenta to affect the fetus and cause significant neurodevelopmental toxicity. Raven`s Colored Progressive Matrices (CPM) and Standarized Progressive Matrices (SPM) test spatial rather than verbal capabilities in children. These test are useful for determining whether prenatal exposure to PCBs/PCDFs cause differential effects on boys and girls. This paper reports results of CPM and SPM from age six to nine year in Yu-Cheng children and their matched controls. Cognative deficits up to 9 years of age were detected n children with prenatal exposure to PCBs and PCDFs, and boys were more affected than girls. 26 refs., 1 fig., 2 tabs.

  19. Chemical Warfare Agent Degradation and Decontamination

    Energy Technology Data Exchange (ETDEWEB)

    Talmage, Sylvia Smith [ORNL; Watson, Annetta Paule [ORNL; Hauschild, Veronique [U.S. Environmental Protection Agency; Munro, Nancy B [ORNL; King, J. [U.S. Army Environmental Center

    2007-02-01

    The decontamination of chemical warfare agents (CWA) from structures, environmental media, and even personnel has become an area of particular interest in recent years due to increased homeland security concerns. In addition to terrorist attacks, scenarios such as accidental releases of CWA from U.S. stockpile sites or from historic, buried munitions are also subjects for response planning. To facilitate rapid identification of practical and effective decontamination approaches, this paper reviews pathways of CWA degradation by natural means as well as those resulting from deliberately applied solutions and technologies; these pathways and technologies are compared and contrasted. We then review various technologies, both traditional and recent, with some emphasis on decontamination materials used for surfaces that are difficult to clean. Discussion is limited to the major threat CWA, namely sulfur mustard (HD, bis(2-chloroethyl)sulfide), VX (O-ethyl S-(2-diisopropylaminoethyl) methylphosphonothioate), and the G-series nerve agents. The principal G-agents are GA (tabun, ethyl N,N-dimethylphosphoramidocyanidate), GB (sarin, isopropyl methylphosphonofluoridate), and GD (soman, pinacolyl methylphosphonofluoridate). The chemical decontamination pathways of each agent are outlined, with some discussion of intermediate and final degradation product toxicity. In all cases, and regardless of the CWA degradation pathway chosen for decontamination, it will be necessary to collect and analyze pertinent environmental samples during the treatment phase to confirm attainment of clearance levels.

  20. Complete genome sequence of the naphthalene-degrading Pseudomonas putida strain ND6.

    Science.gov (United States)

    Li, Shanshan; Zhao, Huabing; Li, Yaxiao; Niu, Shumin; Cai, Baoli

    2012-09-01

    Pseudomonas putida strain ND6 is an efficient naphthalene-degrading bacterium. The complete genome of strain ND6 was sequenced and annotated. The genes encoding the enzymes involved in catechol degradation by the ortho-cleavage pathway were found in the chromosomal sequence, which indicated that strain ND6 is able to metabolize naphthalene by the catechol meta- and ortho-cleavage pathways.

  1. HUWE1 and TRIP12 Collaborate in Degradation of Ubiquitin-Fusion Proteins and Misframed Ubiquitin

    DEFF Research Database (Denmark)

    Poulsen, Esben G; Steinhauer, Cornelia; Lees, Michael

    2012-01-01

    In eukaryotic cells an uncleavable ubiquitin moiety conjugated to the N-terminus of a protein signals the degradation of the fusion protein via the proteasome-dependent ubiquitin fusion degradation (UFD) pathway. In yeast the molecular mechanism of the UFD pathway has been well characterized. Rec...

  2. Kynurenine and serotonin pathways: A review | Adegbusi | Bayero ...

    African Journals Online (AJOL)

    This paper seeks to elucidate the two-key pathways involving tryptophan matabolism, namely, kynurenine and serotonin pathways. In the kynurenine pathway (KP), the discussion considers the steps of the oxidative degradation of tryptophan to yield nicotinate mononucleotide, a precursors for the biosynthesis of nicotinate ...

  3. Comparison of supercritical fluid extraction and Soxhlet extraction for the determination of polychlorinated biphenyls in environmental matrix standard reference materials.

    Science.gov (United States)

    Schantz, M M; Bøwadt, S; Benner, B A; Wise, S A; Hawthorne, S B

    1998-08-14

    Supercritical fluid extraction (SFE) was compared to traditional Soxhlet extraction for the determination of polychlorinated biphenyl congeners in three standard reference materials: SRM 1941a (Organics in Marine Sediment), SRM 1944 (New York/New Jersey Waterway Sediment) and SRM 2974 [Organics in Mussel Tissue (Mytilus edulis) (Freeze-Dried)]. The concentrations determined using SFE compared well with the certified concentrations for the majority of the polychlorinated biphenyl congeners.

  4. Anaerobic Degradation of Benzene and Polycyclic Aromatic Hydrocarbons.

    Science.gov (United States)

    Meckenstock, Rainer U; Boll, Matthias; Mouttaki, Housna; Koelschbach, Janina S; Cunha Tarouco, Paola; Weyrauch, Philip; Dong, Xiyang; Himmelberg, Anne M

    2016-01-01

    Aromatic hydrocarbons such as benzene and polycyclic aromatic hydrocarbons (PAHs) are very slowly degraded without molecular oxygen. Here, we review the recent advances in the elucidation of the first known degradation pathways of these environmental hazards. Anaerobic degradation of benzene and PAHs has been successfully documented in the environment by metabolite analysis, compound-specific isotope analysis and microcosm studies. Subsequently, also enrichments and pure cultures were obtained that anaerobically degrade benzene, naphthalene or methylnaphthalene, and even phenanthrene, the largest PAH currently known to be degradable under anoxic conditions. Although such cultures grow very slowly, with doubling times of around 2 weeks, and produce only very little biomass in batch cultures, successful proteogenomic, transcriptomic and biochemical studies revealed novel degradation pathways with exciting biochemical reactions such as for example the carboxylation of naphthalene or the ATP-independent reduction of naphthoyl-coenzyme A. The elucidation of the first anaerobic degradation pathways of naphthalene and methylnaphthalene at the genetic and biochemical level now opens the door to studying the anaerobic metabolism and ecology of anaerobic PAH degraders. This will contribute to assessing the fate of one of the most important contaminant classes in anoxic sediments and aquifers. © 2016 S. Karger AG, Basel.

  5. The effect of soil mineral phases on the abiotic degradation of selected organic compounds. Final report, June 31, 1990--December 31, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Sandhu, S.S.

    1994-12-31

    Funds were received from the United States Department of Energy to study the effects of soil mineral phases on the rates of abiotic degradation of tetraphenylborate (TPB) and diphenylboronic acid (DPBA). In addition to kaolinite and montmorillonite clay minerals, the role of goethite, corundum, manganite, and rutile in the degradation of organoborates was also evaluated. The effects of DPBA, argon, molecular dioxygen (O{sub 2}), temperature, and organic matter on the degradation of organoborates were also measured. The results indicated that TPB and DPBA degraded rapidly on the mineral surfaces. The initial products generated from the degradation of TPB were DPBA and biphenyl; however, further degradation resulted in the formation of phenylboric acid and phenol which persisted even after TPB disappeared. The data also showed that the rate of TPB degradation was faster in kaolinite, a 1:1 clay mineral, than in montmorillonite, a double layer mineral. The initial degradation of TPB by corundum was much higher than goethite, manganite and rutile. However, no further degradation by this mineral was observed where as the degradation of TPB continued by goethite and rutile minerals. Over all, the degradation rate of TPB was the highest for goethite as compared to the other metal oxide minerals. The degradation of TPB and DPBA was a redox reaction where metals (Fe, Al, Ti, Mn) acted as Lewis acids. DPBA and argon retarded the TPB degradation where as molecular oxygen organic matter and temperature increased the rate of TPB disappearance.

  6. Design and biological evaluation of biphenyl-4-carboxylic acid hydrazide-hydrazone for antimicrobial activity.

    Science.gov (United States)

    Deep, Aakash; Jain, Sandeep; Sharma, Prabodh Chander; Verma, Prabhakar; Kumar, Mahesh; Dora, Chander Parkash

    2010-01-01

    Seven biphenyl-4-carboxylic acid hydrazide-hydrazones have been synthesized. These hydrazone derivatives were characterized by CHN analysis, IR, and 1H NMR spectral data. All the compounds were evaluated for their in vitro antimicrobial activity against two Gram negative strains (Escherichia coli and Pseudomonas aeruginosa) and two Gram positive strains (Bacillus subtilis and Staphylococcus aureus) and fungal strain Candida albicans and Aspergillus niger All newly synthesized compounds exhibited promising results.

  7. A new biphenyl derivative from the mangrove endophytic fungus Phomopsis longicolla HL-2232.

    Science.gov (United States)

    Li, Xiao-Bao; Chen, Guang-Ying; Liu, Rui-Jie; Zheng, Cai-Juan; Song, Xin-Ming; Han, Chang-Ri

    2017-10-01

    A new biphenyl derivative 5,5'-dimethoxybiphenyl-2,2'-diol (1), together with five known compounds (2-5), was isolated from the mangrove endophytic fungus Phomopsis longicolla HL-2232. The structures of these compounds were elucidated using comprehensive spectroscopic methods. The absolute configuration of 4 was determined by single-crystal X-ray diffraction for the first time. The inhibitory activities of all compounds against two Vibrio bacteria were evaluated.

  8. Synthesis and Photophysical Properties of Biphenyl and Terphenyl Arylene?Ethynylene Macrocycles

    OpenAIRE

    Korich, Andrew L.; McBee, Ian A.; Bennion, Jonathan C.; Gifford, Jenna I.; Hughes, Thomas S.

    2014-01-01

    A series of single-walled carbon nanotube precursors, C 3h -symmetric cyclotri(ethynylene)(biphenyl-2,4?-diyl) and cyclotri(ethynylene)(p-terphenyl-2,4?-diyl), have been prepared by a linear stepwise oligomerization?cyclization route and by statistical intermolecular cyclooligomerization. In addition to producing these members of a novel class of arylene ethynylene macrocycles, 1 and 2, the latter statistical process produces the smaller cyclic dimer, cyclodi(ethynylene)(p-terphenyl-2,4?-diyl...

  9. Polychlorinated biphenyls and reproductive hormones in female polar bears at Svalbard.

    OpenAIRE

    Haave, Marte; Ropstad, Erik; Derocher, Andrew E; Lie, Elisabeth; Dahl, Ellen; Wiig, Øystein; Skaare, Janneche U; Jenssen, Bjørn Munro

    2003-01-01

    High concentrations of polychlorinated biphenyls (PCBs) in polar bears from Svalbard have increased concern for that population's reproductive health. We examined whether there were associations between the plasma concentrations of PCBs and reproductive hormones [progesterone (P4)] and 17 beta-estradiol (E2)] in free-living female polar bears from Svalbard. Concentrations of P4 depended on reproductive status, and concentrations were lowest in females with offspring--females with cubs and fem...

  10. 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.

  11. Antiproliferative and pro-apoptotic activity of eugenol-related biphenyls on malignant melanoma cells

    Science.gov (United States)

    Pisano, Marina; Pagnan, Gabriella; Loi, Monica; Mura, Maria Elena; Tilocca, Maria Giovanna; Palmieri, Giuseppe; Fabbri, Davide; Dettori, Maria Antonietta; Delogu, Giovanna; Ponzoni, Mirco; Rozzo, Carla

    2007-01-01

    Background Malignant melanoma is one of the most aggressive skin cancer and chemotherapeutic agents currently in use are still unsatisfactory. Prevention and early diagnosis are the only effective tools against this tumour whose incidence and mortality rates are highly increased during the last decades in fair skin populations. Therefore the search for novel therapeutic approaches is warranted. Aim of this work was to identify and test new compounds with antiproliferative and cytotoxic activity on melanoma cells. We tested eugenol together with six natural and synthetic eugenol-related compounds for their capability to inhibit cell growth on primary melanoma cell lines established from patients' tissue samples. Results Eugenol and isoeugenol monomers and their respective O-methylated forms did not show to inhibit melanoma cells proliferation. Conversely, the dimeric forms (biphenyls) showed some antiproliferative activity which was mild for dehydrodieugenol, higher for its O,O'-methylated form (O,O'-dimethyl-dehydrodieugenol), and markedly pronounced for the racemic mixture of the brominated biphenyl (6,6'-dibromo-dehydrodieugenol) (S7), being its enantiomeric form (S) the most effective compared to the other compounds. Such activity resulted to be selective against tumour cells, without affecting cultured normal human skin fibroblasts. Dose and time dependence curves have been obtained for the enantiomeric form S7-(S). Then IC50 and minimal effective doses and times have been established for the melanoma cell lines tested. TUNEL and phosphatidylserine exposure assays demonstrated the occurrence of apoptotic events associated with the antiproliferative activity of S7-(S). Cytotoxic activity and apoptosis induced by treating melanoma cells with eugenol-related biphenyls was partially dependent by caspase activation. Conclusion Our findings demonstrate that the eugenol related biphenyl (S)-6,6'-dibromo-dehydrodieugenol elicits specific antiproliferative activity on

  12. Cholesterol biosynthesis in polychlorinated biphenyl-treated rats

    International Nuclear Information System (INIS)

    Kling, D.; Gamble, W.

    1982-01-01

    After administration of polychlorinated biphenly (PCB) at 0.055 (w/w) of the diet to Wistar rats for 30 days, followed by intraperitioneal injection of tritiated water, [ 14 C]mevalonate, and [ 14 C]acetate, there was a decrease in cholesterol biosynthesis in rat liver. No significant change in cholesterol formation was observed when PCB was administered at 0.01% (w/w) of the diet. In vitro inhibition of cholesterol synthesis by rat liver microsomes was observed with PCB. Squalene 2,3-oxidocyclase activity of rat liver microsomes was not significantly altered. Desmosterol delta 24 reductase activity was inhibited only at relatively high concentrations of PCB. There was increased incorporation of radioactivity into squalene and lanosterol, in vitro, in the presence of PCB. The primary inhibition of cholesterol biosynthesis appears to be at the demethylation and rearrangement reactions between lanosterol and cholesterol in the biosynthetic pathway

  13. Molecular pathways

    DEFF Research Database (Denmark)

    Cox, Thomas R; Erler, Janine Terra

    2014-01-01

    that 45% of deaths in the developed world are linked to fibrotic disease. Fibrosis and cancer are known to be inextricably linked; however, we are only just beginning to understand the common and overlapping molecular pathways between the two. Here, we discuss what is known about the intersection...... of fibrosis and cancer, with a focus on cancer metastasis, and highlight some of the exciting new potential clinical targets that are emerging from analysis of the molecular pathways associated with these two devastating diseases. Clin Cancer Res; 20(14); 3637-43. ©2014 AACR....

  14. Tunable High-Pressure Field Operating on a Cationic Biphenyl Derivative Intercalated in Clay Minerals.

    Science.gov (United States)

    Tominaga, Makoto; Nishioka, Yukihiro; Tani, Seiji; Suzuki, Yasutaka; Kawamata, Jun

    2017-08-09

    We propose a methodology for applying a pseudo uniaxial pressure to an organic molecule under ordinary temperature and pressure, namely by intercalation into smectites. The pseudo pressure on a biphenyl derivative (BP) was estimated from the averaged dihedral angle around the central bond of BP. In a high hydrostatic pressure field, biphenyl takes a planar conformation. In the interlayer space of synthetic saponite (SSA), the averaged dihedral angle of BP at a loading level of 27% versus the cation exchange capacity was ~26.3°, which indicates that the pseudo pressure applied to BP in the SSA interlayer space corresponds to 0.99 GPa. The high pseudo-pressure field in the interlayer space of SSA was also confirmed by absorption measurements. The dihedral angle around the central bond of the biphenyl moiety decreased to enhance the planarity of the molecule, mainly in response to the electrostatic force that operates between the negatively charged SSA layer and the interlayer cation. The pseudo pressure operating on BP in the smectite interlayer space could be controlled by varying the smectite layer charge density and/or the BP loading level. By using this methodology, controllable pseudo high-pressure properties of organic molecules can be obtained at ordinary temperatures and pressures.

  15. Syntrophy in Methanogenic Degradation

    NARCIS (Netherlands)

    Worm, P.; Müller, N.; Plugge, C.M.; Stams, A.J.M.; Schink, B.

    2010-01-01

    This chapter deals with microbial communities of bacteria and archaea that closely cooperate in methanogenic degradation and perform metabolic functions in this community that neither one of them could carry out alone. The methanogenic degradation of fatty acids, alcohols, most aromatic compounds,

  16. Degradations and Rearrangement Reactions

    Science.gov (United States)

    Zhang, Jianbo

    This section deals with recent reports concerning degradation and rearrangement reactions of free sugars as well as some glycosides. The transformations are classified in chemical and enzymatic ways. In addition, the Maillard reaction will be discussed as an example of degradation and rearrangement transformation and its application in current research in the fields of chemistry and biology.

  17. K Basin sludge polychlorinated biphenyl removal technology assessment

    International Nuclear Information System (INIS)

    Ashworth, S.C.

    1998-01-01

    The two Hanford K Basins are water-filled concrete pools that contain over 2,100 metric tons of N Reactor fuel elements stored in aluminum or stainless steel canisters. During the time the fuel has been stored, approximately 50 m3 of heterogeneous solid material have accumulated in the basins. This material, referred to as sludge, is a mixture of fuel corrosion products, metallic bits of spent fuel and zirconium clad iron and metal corrosion products and silica from migrating sands. Some of the sludges also contain PCBs. The congener group of PCBs was identified as Aroclor 1254. The maximum concentration of sludge PCBS was found to be 140 ppm (as settled wet basis). However, the distribution of the PCBs is non-uniform throughout the sludge (i.e., there are regions of high and low concentrations and places where no PCBs are present). Higher concentrations could be present at various locations. Aroclors 1016/1242, 1221, 1248, 1254, and 1260 were identified and quantified in K West (KW) Canister sludge. In some of these samples, the concentration of 1260 was higher than 1254. The sludge requires pre-treatment to meet tank farm waste acceptance criteria, Among the numerous requirements, the sludge should be retreated so that it does not contain regulated levels of Toxic Substances Control Act (TSCA) compounds. Because of their stable chemistry and relative insolubility in water, PCBs are difficult to treat. They also resist degradation from heat and electrical charges. This stability has resulted in environmental persistence which has prompted the development of a variety of new cleanup processes including supercritical processes, advanced oxidation, dehalogenation and others. Hopefully, most of the new processes are discussed herein. Information on new processes are being received and will be evaluated in a future revision

  18. K Basin sludge polychlorinated biphenyl removal technology assessment

    Energy Technology Data Exchange (ETDEWEB)

    Ashworth, S.C.

    1998-08-25

    The two Hanford K Basins are water-filled concrete pools that contain over 2,100 metric tons of N Reactor fuel elements stored in aluminum or stainless steel canisters. During the time the fuel has been stored, approximately 50 m3 of heterogeneous solid material have accumulated in the basins. This material, referred to as sludge, is a mixture of fuel corrosion products, metallic bits of spent fuel and zirconium clad iron and metal corrosion products and silica from migrating sands. Some of the sludges also contain PCBs. The congener group of PCBs was identified as Aroclor 1254. The maximum concentration of sludge PCBS was found to be 140 ppm (as settled wet basis). However, the distribution of the PCBs is non-uniform throughout the sludge (i.e., there are regions of high and low concentrations and places where no PCBs are present). Higher concentrations could be present at various locations. Aroclors 1016/1242, 1221, 1248, 1254, and 1260 were identified and quantified in K West (KW) Canister sludge. In some of these samples, the concentration of 1260 was higher than 1254. The sludge requires pre-treatment to meet tank farm waste acceptance criteria, Among the numerous requirements, the sludge should be retreated so that it does not contain regulated levels of Toxic Substances Control Act (TSCA) compounds. Because of their stable chemistry and relative insolubility in water, PCBs are difficult to treat. They also resist degradation from heat and electrical charges. This stability has resulted in environmental persistence which has prompted the development of a variety of new cleanup processes including supercritical processes, advanced oxidation, dehalogenation and others. Hopefully, most of the new processes are discussed herein. Information on new processes are being received and will be evaluated in a future revision.

  19. Macromolecular Degradation Systems and Cardiovascular Aging.

    Science.gov (United States)

    Nakayama, Hiroyuki; Nishida, Kazuhiko; Otsu, Kinya

    2016-05-13

    Aging-related cardiovascular diseases are a rapidly increasing problem worldwide. Cardiac aging demonstrates progressive decline of diastolic dysfunction of ventricle and increase in ventricular and arterial stiffness accompanied by increased fibrosis stimulated by angiotensin II and proinflammatory cytokines. Reactive oxygen species and multiple signaling pathways on cellular senescence play major roles in the process. Aging is also associated with an alteration in steady state of macromolecular dynamics including a dysfunction of protein synthesis and degradation. Currently, impaired macromolecular degradation is considered to be closely related to enhanced inflammation and be involved in the process and mechanism of cardiac aging. Herein, we review the role and mechanisms of the degradation system of intracellular macromolecules in the process and pathophysiology of cardiovascular aging. © 2016 American Heart Association, Inc.

  20. Current Status on Biochemistry and Molecular Biology of Microbial Degradation of Nicotine

    Science.gov (United States)

    Gurusamy, Raman; Natarajan, Sakthivel

    2013-01-01

    Bioremediation is one of the most promising methods to clean up polluted environments using highly efficient potent microbes. Microbes with specific enzymes and biochemical pathways are capable of degrading the tobacco alkaloids including highly toxic heterocyclic compound, nicotine. After the metabolic conversion, these nicotinophilic microbes use nicotine as the sole carbon, nitrogen, and energy source for their growth. Various nicotine degradation pathways such as demethylation pathway in fungi, pyridine pathway in Gram-positive bacteria, pyrrolidine pathway, and variant of pyridine and pyrrolidine pathways in Gram-negative bacteria have been reported. In this review, we discussed the nicotine-degrading pathways of microbes and their enzymes and biotechnological applications of nicotine intermediate metabolites. PMID:24470788

  1. Purex diluent degradation

    International Nuclear Information System (INIS)

    Tallent, O.K.; Mailen, J.C.; Pannell, K.D.

    1984-02-01

    The chemical degradation of normal paraffin hydrocarbon (NPH) diluents both in the pure state and mixed with 30% tributyl phosphate (TBP) was investigated in a series of experiments. The results show that degradation of NPH in the TBP-NPH-HNO 3 system is consistent with the active chemical agent being a radical-like nitrogen dioxide (NO 2 ) molecule, not HNO 3 as such. Spectrophotometric, gas chromatographic, mass spectrographic, and titrimetric methods were used to identify the degradation products, which included alkane nitro and nitrate compounds, alcohols, unsaturated alcohols, nitro alcohols, nitro alkenes, ketones, and carboxylic acids. The degradation rate was found to increase with increases in the HNO 3 concentration and the temperature. The rate was decreased by argon sparging to remove NO 2 and by the addition of butanol, which probably acts as a NO 2 scavenger. 13 references, 11 figures

  2. Bacterial Degradation of Pesticides

    DEFF Research Database (Denmark)

    Knudsen, Berith Elkær

    . Bioaugmentation i.e. addition of specific degrader organisms, has been suggested as an environmentally friendly and economically competitive strategy for cleaning polluted sites. Several organisms have been isolated, capable of degrading different compounds. However the capacity to degrade the desired compound...... that it was possible to produce MSH1 in large amounts within 12-24 hours. Moreover, mineralization experiments showed that the capacity to mineralize BAM was kept intact, and that maximal mineralization rate was not influenced by the state of the cells at the time of harvest (in exponential or stationary phase...... SRS2, Variovorax SRS16 and Arthrobacter globiformis D47. The degradation capacity of each strain individually as well as two- and three-member consortia was studied in a sand column set up. Glass beads were added to the set up to create a dry patch, separating the organisms and the diuron-spiked sand...

  3. How do polymers degrade?

    Science.gov (United States)

    Lyu, Suping

    2011-03-01

    Materials derived from agricultural products such as cellulose, starch, polylactide, etc. are more sustainable and environmentally benign than those derived from petroleum. However, applications of these polymers are limited by their processing properties, chemical and thermal stabilities. For example, polyethylene terephthalate fabrics last for many years under normal use conditions, but polylactide fabrics cannot due to chemical degradation. There are two primary mechanisms through which these polymers degrade: via hydrolysis and via oxidation. Both of these two mechanisms are related to combined factors such as monomer chemistry, chain configuration, chain mobility, crystallinity, and permeation to water and oxygen, and product geometry. In this talk, we will discuss how these materials degrade and how the degradation depends on these factors under application conditions. Both experimental studies and mathematical modeling will be presented.

  4. Thraustochytrid protists degrade hydrocarbons

    Digital Repository Service at National Institute of Oceanography (India)

    Raikar, M.T.; Raghukumar, S.; Vani, V.; David, J.J.; Chandramohan, D.

    Although thraustochytrid protists are known to be of widespread occurrence in the sea, their hydrocarbon-degrading abilities have never been investigated. We isolated thraustochytrids from coastal waters and sediments of Goa coast by enriching MPN...

  5. Degradation of fluorotelomer alcohols

    DEFF Research Database (Denmark)

    Ellis, David A; Martin, Jonathan W; De Silva, Amila O

    2004-01-01

    Human and animal tissues collected in urban and remote global locations contain persistent and bioaccumulative perfluorinated carboxylic acids (PFCAs). The source of PFCAs was previously unknown. Here we present smog chamber studies that indicate fluorotelomer alcohols (FTOHs) can degrade...

  6. Degradation of substituted indoles by an indole-degrading methanogenic consortium

    Energy Technology Data Exchange (ETDEWEB)

    Jidong Gu; Berry, D.F. (Virginia Polytechnic Inst. and State Univ., Blacksburg (United States))

    1991-09-01

    Degradation of indole-degrading methanogenic consortium enriched from sewage sludge proceeded through a two-step hydroxylation pathway yielding oxindole and isatin. The ability of this consortium to hydroxylate and subsequently degrade-substituted indoles was investigated. Of the substituted indoles tested, the consortium was able to transform or degrade 3-methylindole, and 3-indolyl acetate. Oxindole, 3-methyloxindole, and indoxyl were identified as metabolites of indole, 3-methylindole, and 3-indolyl acetate degradation, respectively. Isatin (indole-2, 3-dione) was produced as an intermediate when the acetate degradation, respectively, Isatin (indole-2,3-dione) was produced as an intermediate when the consortium was amended with oxindole, providing evidence that degradation of indole proceeded through successive hydroxylation of the 2- and 3-positions prior to ring cleavage between the C-2 and C-3 atoms on the pyrrole ring of indole. The presence of a methyl group ({emdash}CH{sub 3}) at either the 1- or 2-position of indole inhibited the initial hydroxylation reaction. The substituted indole, 3-methylindole, was hydroxylated in the 2-position but not in the 3 position and could not be further metabolized through the oxindole-isatin pathway. Indoxyl (indole-3-one), the deacetylated product of 3-indolyl acetate, was not hydroxylated in the 2-position and thus was not further metabolized by the consortium. When an H atom or electron-donating group (i.e., {emdash}CH{sub 3}) was present at the 3-position, hydroxylation proceeded at the 2-position, but the presence of electron-withdrawing substituent groups (i.e., {emdash}OH or {emdash}COOH) at the 3-position inhibited hydroxylation.

  7. Transient spectral hole burning observed on the single-molecule level in terrylene-doped biphenyl

    International Nuclear Information System (INIS)

    Pärs, M.; Palm, V.; Kikas, J.

    2014-01-01

    We use the method of fluorescence correlation spectroscopy to analyze the single-molecule (SM) spectroscopy data earlier recorded for a special type of terrylene SM impurity center (referred as “spectrally confined unstable molecule”, SCM) in an incommensurate single crystal of biphenyl. The SCM's SM line seems to be chaotically jumping around within a broad “spectral envelope” and was first considered being subject to a peculiar spectral diffusion behavior. However, our correlation analysis reveals that all the features observed for SCM at 1.8 K are consistent with an assumption that this SM center participates in a process of reversible (transient) spectral hole burning (THB) earlier observed for terrylene-doped polycrystalline biphenyl. No observations of THB processes on SM level have been so far reported for this impurity system, partially due to a low concentration of relevant impurity centers. Another reason making searching for such centers experimentally challenging is an unusual SM line behavior: the photoinduced transition to a metastable “dark state” leads to the SM line saturational broadening, which is much stronger than the triplet broadening. Hence required prolonged observation is often prevented by an SM act of persistent spectral hole burning. - Highlights: • SCM—special type of terrylene single-molecule center in incommensurate biphenyl. • An unusually stable SCM was investigated during several hours at T=1.8 K. • SCM undergoes photoinduced transitions to an unknown metastable “dark state” (DS). • The long DS lifetime causes strong saturational broadening of SCM spectral line. • SCM participates in an earlier observed process of transient hole burning

  8. Structure of the Mesophases Formed by a Perfluoroalkyl/Biphenyl Compound. Amphiphilic and Steric Effects

    Science.gov (United States)

    Pensec, Sandrine; Tournilhac, François-Genès; Bassoul, Pierre

    1996-11-01

    We describe the synthesis and mesomorphic behaviour of 4-(1H,1H-perfluorooctyloxy)- 4'-methoxy biphenyl. Two mesophases of smectic E and smectic A types were observed. X-ray diffraction study of the smectic E phase indicates a herringbone arrangement of the biphenyl cores, the perfluoroalkyl chains being in a molten state. The {S_E to S_A} transition is related to the melting of the biphenyl sublattice. In both phases, the flexibility of perfluoroalkyl chains permits the area matching between the two segregated sublayers. Nous décrivons la synthèse et les propriétés mésomorphes du 4-(1H,1H-perfluorooctyloxy)- 4'-méthoxy biphényle. Ce composé forme deux mésophases de type smectique E et smectique A. L'analyse par diffraction des rayons X révèle, dans le cas de la phase smectique E un arrangement en chevrons des coeurs biphényles, les chaînes perfluoroalkyles se trouvant dans un état désordonné. La transition {S_E to S_A} correspond à la fusion partielle de la sous-couche biphényle. Dans les deux phases smectiques, la flexibilité des chaînes perfluoroalkyles permet l'adéquation des aires moléculaires entre les deux sous-couches ségrégées.

  9. Static analysis of a Model of the LDL degradation pathway

    DEFF Research Database (Denmark)

    Pilegaard, Henrik; Nielson, Flemming; Nielson, Hanne Riis

    2005-01-01

    BioAmbients is a derivative of mobile ambients that has shown promise of describing interesting features of the behaviour of biological systems. As for other ambient calculi static program analysis can be used to compute safe approximations of the behavior of modelled systems. We use these tools ...... to model and analyse the production of cholesterol in living cells and show that we are able to pinpoint the difference in behaviour between models of healthy systems and models of mutated systems giving rise to known diseases....

  10. A probable pathway in the degradation of 2-methoxyethanol by ...

    African Journals Online (AJOL)

    methoxyethanol was isolated from anaerobic sewage sludge. The bacterium utilizes 2-methoxyethanol as sole source of carbon and energy. In a time course experiment Pseudomonas sp. strain VB was grown in 2-methoxyethanol, ethylene glycol, ...

  11. Rapid detection of polychlorinated biphenyls at trace levels in real environmental samples by surface-enhanced Raman scattering.

    Science.gov (United States)

    Zhou, Qin; Zhang, Xian; Huang, Yu; Li, Zhengcao; Zhang, Zhengjun

    2011-01-01

    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.

  12. Assessment of polychlorinated biphenyls and mercury levels in soil and biological samples from San Felipe, Nuevo Mercurio, Zacatecas, Mexico.

    Science.gov (United States)

    Costilla-Salazar, Rogelio; Trejo-Acevedo, Antonio; Rocha-Amador, Diana; Gaspar-Ramírez, Octavio; Díaz-Barriga, Fernando; Pérez-Maldonado, Iván Nelinho

    2011-02-01

    The aim of this work was to evaluate contamination by polychlorinated biphenyls and mercury in soil, and to assess exposure level to both contaminants in children living in San Felipe, Nuevo Mercurio, Zacatecas, Mexico. We found soil levels of total polychlorinated biphenyls ranging from non detectable (nd) to 190 μg/kg. Mercury soil levels ranged from 8.9 to 10215.0 mg/kg. Exposure levels of total polychlorinated biphenyls assessed in blood and urinary mercury in children living in the studied community were 1,600 ± 8,800 ng/g lipid and 4.2 ± 7.1 μg/g creatinine, respectively.

  13. Polychlorinated biphenyls (PCBs) in the frame of the dismantling of nuclear facilities

    International Nuclear Information System (INIS)

    Hagenbart, Lars; Held, Christian; Reichert, Alexander

    2013-01-01

    During construction and maintenance of nuclear facilities PCB (polychlorinated biphenyls) containing paints were used in a large extent in the past. The WAK dismantling and disposal Company has dismantles such facilities and identified the PCB in the buildings. Besides the radionuclides the conventional hazardous material group of the PCBs has also to be disposed. The respective legal regulations have to be considered. In the frame of the contribution the radiological release of building structures with respect to re-use or demolition and residual PCB containing materials is discussed. The radiological disposal in final repositories and the conventional disposal regulations for releasable residual wastes are reported.

  14. Measurement and prediction of (solid + liquid) equilibria of (alkanediamine + biphenyl) mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Khimeche, Kamel [Ecole Militaire Polytechnique EMP, BP 17 Bordj-el-Bahri (Algeria); Laboratoire de Thermodynamique et de Modelisation Moleculaire, Faculte de Chimie, USTHB, BP. 32 El-Alia, 16111 Bab-Ezzouar, Alger (Algeria); Dahmani, Abdallah [Laboratoire de Thermodynamique et de Modelisation Moleculaire, Faculte de Chimie, USTHB, BP. 32 El-Alia, 16111 Bab-Ezzouar, Alger (Algeria)]. E-mail: abdahmani@yahoo.fr

    2006-10-15

    Diamines represent, besides many technically important classes of substance, a particularly interesting family of molecules for the purpose of testing group-contribution models. A differential scanning calorimetry (DSC) was used to determine binary (solid + liquid) phase equilibria for {l_brace}diamines NH{sub 2}-(CH{sub 2}) {sub n}-NH{sub 2} (n = 6, 8, 9, and 12) + biphenyl{r_brace} mixtures. Results obtained with this technique are compared with those predicted by modified UNIFAC (Larsen and Gmehling) and DISQUAC models. It was found out that all the systems are eutectic and deviations were observed between experimental and predicted SLE.

  15. Residues of organochlorine pesticides and polychlorinated biphenyls and autopsy data for bald eagles, 1971-72

    Science.gov (United States)

    Cromartie, E.; Reichel, W.L.; Locke, L.N.; Belisle, A.A.; Kaiser, T.E.; Lamont, T.G.; Mulhern, B.M.; Prouty, R.M.; Swineford, D.M.

    1975-01-01

    Thirty-seven bald eagles found sick or dead in 18 States during 1971-72 were analyzed for organochlorine pesticides and polychlorinated biphenyls (PCB's). DDE and PCB's were detected in all bald eagle carcasses; 30 carcasses contained DDD and 28 contained dieldrin. Four eagles contained possibly lethal levels of dieldrin and nine eagles had been poisoned by thallium. Autopsies revealed that illegal shooting was the most common cause of mortality. Since 1964 when data were first collected, 8 of the 17 eagles obtained from Maryland, Virginia, South Carolina, and Florida possibly died from dieldrin poisoning; all four specimens from Maryland and Virginia were from the Chesapeake Bay Tidewater area.

  16. 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...

  17. 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.

  18. Autophagy contributes to degradation of Hirano bodies.

    Science.gov (United States)

    Kim, Dong-Hwan; Davis, Richard C; Furukawa, Ruth; Fechheimer, Marcus

    2009-01-01

    Hirano bodies are actin-rich inclusions reported most frequently in the hippocampus in association with a variety of conditions including neurodegenerative diseases, and aging. We have developed a model system for formation of Hirano bodies in Dictyostelium and cultured mammalian cells to permit detailed studies of the dynamics of these structures in living cells. Model Hirano bodies are frequently observed in membrane-enclosed vesicles in mammalian cells consistent with a role of autophagy in the degradation of these structures. Clearance of Hirano bodies by an exocytotic process is supported by images from electron microscopy showing extracellular release of Hirano bodies, and observation of Hirano bodies in the culture medium of Dictyostelium and mammalian cells. An autophagosome marker protein Atg8-GFP, was co-localized with model Hirano bodies in wild type Dictyostelium cells, but not in atg5(-) or atg1-1 autophagy mutant strains. Induction of model Hirano bodies in Dictyostelium with a high level expression of 34 kDa DeltaEF1 from the inducible discoidin promoter resulted in larger Hirano bodies and a cessation of cell doubling. The degradation of model Hirano bodies still occurred rapidly in autophagy mutant (atg5(-)) Dictyostelium, suggesting that other mechanisms such as the ubiquitin-mediated proteasome pathway could contribute to the degradation of Hirano bodies. Chemical inhibition of the proteasome pathway with lactacystin, significantly decreased the turnover of Hirano bodies in Dictyostelium providing direct evidence that autophagy and the proteasome can both contribute to degradation of Hirano bodies. Short term treatment of mammalian cells with either lactacystin or 3-methyl adenine results in higher levels of Hirano bodies and a lower level of viable cells in the cultures, supporting the conclusion that both autophagy and the proteasome contribute to degradation of Hirano bodies.

  19. Occurrence, spatial distribution, sources, and risks of polychlorinated biphenyls and heavy metals in surface sediments from a large eutrophic Chinese lake (Lake Chaohu)

    DEFF Research Database (Denmark)

    He, Wei; Bai, Ze-Lin; Liu, Wen-Xiu

    2016-01-01

    Chaohu was 672 pg g−1 dry weight (dw), with a range of 7 to 3999 pg g−1 dw, which was lower than other water bodies worldwide. The majority of heavy metals were detected at all sampling locations, except for Sr, B, and In. Concentrations of Al, Fe, Ca, Mn, Sr, Co, Zn, Cd, Pb, and Hg were similar......Surface sediment from large and eutrophic Lake Chaohu was investigated to determine the occurrence, spatial distribution, sources, and risks of polychlorinated biphenyls (PCBs) and heavy metals in one of the five biggest freshwater lakes in China. Total concentration of PCBs (Σ34PCBs) in Lake...... and microbial degradation accounted for 34.2 % and 65.8 % of total PCBs using PMF, and PMF revealed that natural and anthropogenic sources of heavy metals accounted for 38.1 % and 61.8 %, respectively. CA indicated that some toxic heavy metals (e.g., Cd, In, Tl, and Hg) were associated with Ca–Na–Mg minerals...

  20. Hydrodechlorination of polychlorinated biphenyls in contaminated soil from an e-waste recycling area, using nanoscale zerovalent iron and Pd/Fe bimetallic nanoparticles.

    Science.gov (United States)

    Chen, Xi; Yao, Xiaoyan; Yu, Chunna; Su, Xiaomei; Shen, Chaofeng; Chen, Chen; Huang, Ronglang; Xu, Xinhua

    2014-04-01

    Soil pollution by polychlorinated biphenyls (PCBs) arising from the crude disposal and recycling of electronic and electrical waste (e-waste) is a serious issue, and effective remediation technologies are urgently needed. Nanoscale zerovalent iron (nZVI) and bimetallic systems have been shown to promote successfully the destruction of halogenated organic compounds. In the present study, nZVI and Pd/Fe bimetallic nanoparticles synthesized by chemical deposition were used to remove 2,2',4,4',5,5'-hexachlorobiphenyl from deionized water, and then applied to PCBs contaminated soil collected from an e-waste recycling area. The results indicated that the hydrodechlorination of 2,2',4,4',5,5'-hexachlorobiphenyl by nZVI and Pd/Fe bimetallic nanoparticles followed pseudo-first-order kinetics and Pd loading was beneficial to the hydrodechlorination process. It was also found that the removal efficiencies of PCBs from soil achieved using Pd/Fe bimetallic nanoparticles were higher than that achieved using nZVI and that PCBs degradation might be affected by the soil properties. Finally, the potential challenges of nZVI application to in situ remediation were explored.

  1. Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in sediments of Liaohe River: levels, spatial and temporal distribution, possible sources, and inventory.

    Science.gov (United States)

    Lv, Jiapei; Zhang, Yuan; Zhao, Xin; Zhou, Changbo; Guo, Changsheng; Luo, Yi; Meng, Wei; Zou, Guofang; Xu, Jian

    2015-03-01

    Spatial and seasonal variations of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in the sediment of Liaohe River were investigated in this study. A total of 29 surface sediment samples were collected in May and September in 2013. Results showed that levels of the two classes of compounds were higher in September than in May. The total concentration of PBDEs (∑8PBDEs) ranged from 0.30 to 5.09 ng g(-1) in May and from 0.17 to 13.73 ng g(-1) in September, respectively, and BDE 209 was the dominant compound. The total concentration of PCBs (∑33PCBs) was in the range of 4.92-76.86 and 11.69-179.61 ng g(-1) in May and September, respectively, with tri- and tetra-CBs dominated in the total PCBs in the sediments. According to the congener profiles and the principal component analysis, the major sources of PCBs and PBDEs in sediments of Liaohe River were from the usage of commercial products and industrial activities, and the degradation of high brominated BDEs also contributed to the current PBDEs in the sediments. The mass inventories of PBDEs and PCBs in the sediments of Liaohe River were 1.74 and 21.96 t, respectively, indicating that Liaohe River sediments may act as the potential sources of PBDEs and PCBs to the downstream coastal areas.

  2. The inhibition of LPS-induced splenocyte proliferation by ortho-substituted and microbially dechlorinated polychlorinated biphenyls is associated with a decreased expression of cyclin D2

    International Nuclear Information System (INIS)

    Smithwick, L. Ashley; Quensen, John F.; Smith, Andrew; Kurtz, David T.; London, Lucille; Morris, Pamela J.

    2004-01-01

    Immunological effects of polychlorinated biphenyls (PCBs) have been demonstrated in our laboratories with the preferential inhibition of lipopolysaccharide (LPS)-induced splenocyte proliferation by ortho-substituted PCB congeners. An investigation of the mechanism behind this immunotoxicity revealed an interruption in the progression of murine lymphocytes from G 0 /G 1 into S phase by Aroclor 1242 and the di-ortho-substituted congener, 2,2'-chlorobiphenyl (CB), whereas, a non-ortho-substituted congener, 4,4'-CB, did not affect cell cycle progression. This interruption of cell cycle progression by 2,2'-CB and Aroclor 1242 was associated with a decreased expression of the cell cycle regulatory protein, cyclin D2, while expression was not affected by exposure to the non-ortho-substituted 4,4'-CB. These results suggest the preferential inhibition of LPS-induced splenocyte proliferation by ortho-substituted congeners is a result of a decreased expression of cyclin D2, which leads to an interruption in cell cycle progression. In addition, PCB mixtures with an increased percentage of chlorines in the ortho position following an environmentally occurring degradation process inhibited LPS-induced proliferation, interrupted cell cycle progression, and decreased cyclin D2 expression. This study provides evidence for a mechanism of action of the immunological effects of ortho-substituted individual congeners as well as environmentally relevant mixtures enriched in congeners with this substitution pattern

  3. Analysis the mixtures of polyphenyls by gas chromatrogaphie. 1.- Area response for biphenyl and terphenyls relative to triphenylmethane

    International Nuclear Information System (INIS)

    Perez Garcia, M.

    1966-01-01

    The relative performances of the thermal conductivity and flame ionization detectors towards triphenylmethane were investigated for each one of the components of biphenyl of biphenyl and terphenyl mixtures. The influence of the concentration of the considered compound as well as the influence derived from the present of all other components on the above-mentioned relative performance were studied. A 2 m long column filled with 50-70 mesh stomacher containing 20% apiezon L was used to carry out the study with the thermal conductivity detector by keeping the column at 300 degree centigree using helium gas as carrier. (Author) 13 refs

  4. Drift Degradation Analysis

    International Nuclear Information System (INIS)

    D. Kicker

    2004-01-01

    Degradation of underground openings as a function of time is a natural and expected occurrence for any subsurface excavation. Over time, changes occur to both the stress condition and the strength of the rock mass due to several interacting factors. Once the factors contributing to degradation are characterized, the effects of drift degradation can typically be mitigated through appropriate design and maintenance of the ground support system. However, for the emplacement drifts of the geologic repository at Yucca Mountain, it is necessary to characterize drift degradation over a 10,000-year period, which is well beyond the functional period of the ground support system. This document provides an analysis of the amount of drift degradation anticipated in repository emplacement drifts for discrete events and time increments extending throughout the 10,000-year regulatory period for postclosure performance. This revision of the drift degradation analysis was developed to support the license application and fulfill specific agreement items between the U.S. Nuclear Regulatory Commission (NRC) and the U.S. Department of Energy (DOE). The earlier versions of ''Drift Degradation Analysis'' (BSC 2001 [DIRS 156304]) relied primarily on the DRKBA numerical code, which provides for a probabilistic key-block assessment based on realistic fracture patterns determined from field mapping in the Exploratory Studies Facility (ESF) at Yucca Mountain. A key block is defined as a critical block in the surrounding rock mass of an excavation, which is removable and oriented in an unsafe manner such that it is likely to move into an opening unless support is provided. However, the use of the DRKBA code to determine potential rockfall data at the repository horizon during the postclosure period has several limitations: (1) The DRKBA code cannot explicitly apply dynamic loads due to seismic ground motion. (2) The DRKBA code cannot explicitly apply loads due to thermal stress. (3) The DRKBA

  5. Drift Degradation Analysis

    Energy Technology Data Exchange (ETDEWEB)

    D. Kicker

    2004-09-16

    Degradation of underground openings as a function of time is a natural and expected occurrence for any subsurface excavation. Over time, changes occur to both the stress condition and the strength of the rock mass due to several interacting factors. Once the factors contributing to degradation are characterized, the effects of drift degradation can typically be mitigated through appropriate design and maintenance of the ground support system. However, for the emplacement drifts of the geologic repository at Yucca Mountain, it is necessary to characterize drift degradation over a 10,000-year period, which is well beyond the functional period of the ground support system. This document provides an analysis of the amount of drift degradation anticipated in repository emplacement drifts for discrete events and time increments extending throughout the 10,000-year regulatory period for postclosure performance. This revision of the drift degradation analysis was developed to support the license application and fulfill specific agreement items between the U.S. Nuclear Regulatory Commission (NRC) and the U.S. Department of Energy (DOE). The earlier versions of ''Drift Degradation Analysis'' (BSC 2001 [DIRS 156304]) relied primarily on the DRKBA numerical code, which provides for a probabilistic key-block assessment based on realistic fracture patterns determined from field mapping in the Exploratory Studies Facility (ESF) at Yucca Mountain. A key block is defined as a critical block in the surrounding rock mass of an excavation, which is removable and oriented in an unsafe manner such that it is likely to move into an opening unless support is provided. However, the use of the DRKBA code to determine potential rockfall data at the repository horizon during the postclosure period has several limitations: (1) The DRKBA code cannot explicitly apply dynamic loads due to seismic ground motion. (2) The DRKBA code cannot explicitly apply loads due to thermal

  6. Degradation of diuron in aqueous solution by dielectric barrier discharge

    Energy Technology Data Exchange (ETDEWEB)

    Feng Jingwei [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment Nanjing University, Nanjing 210093 (China); Zheng Zheng [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment Nanjing University, Nanjing 210093 (China)], E-mail: zzheng@nju.edu.cn; Sun Yabing; Luan Jingfei; Wang Zhen; Wang Lianhong; Feng Jianfang [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment Nanjing University, Nanjing 210093 (China)

    2008-06-15

    Degradation of diuron in aqueous solution was conducted in a dielectric barrier discharge (DBD) reactor and the proposed degradation mechanism was investigated in detail. The factors that affect the degradation of diuron were examined. The degradation efficiency of diuron and the removal of total organic carbon (TOC) increased with increasing input power, and the degradation of diuron by DBD fitted first-order kinetics. Both strong acidic and alkaline solution conditions could improve diuron degradation efficiency and TOC removal rate. Degradation of diuron could be accelerated or inhibited in the presence of H{sub 2}O{sub 2} depending on the dosage. The degradation efficiency increased dramatically with adding Fe{sup 2+}. The removal of TOC and the amount of the detected Cl{sup -}, NO{sub 3}{sup -} and NH{sub 4}{sup +} were increased in the presence of Fe{sup 2+}. The concentrations of oxalic and acetic acids were almost the same in the absence and presence of Fe{sup 2+}, but high concentration of formic acid was accumulated in the presence of Fe{sup 2+}. The main degradation pathway of diuron by DBD involved a series of dechlorination-hydroxylation, dealkylation and oxidative opening of the aromatic ring processes.

  7. 3D multidisciplinary numerical model of polychlorinated biphenyl dynamics on the Black Sea north-western shelf

    Science.gov (United States)

    Bagaiev, Andrii; Ivanov, Vitaliy

    2014-05-01

    The Black Sea north-western shelf plays a key role in economics of the developing countries such as Ukraine due to food supply, invaluable recreational potential and variety of the relevant maritime shipping routes. On the other hand, a shallow flat shelf is mostly affected by anthropogenic pollution, eutrophication, hypoxia and harmful algae blooms. The research is focused on modeling the transport and transformation of PCBs (PolyChlorinated Biphenyls) because they are exceedingly toxic and highly resistant to degradation, hence cumulatively affect marine ecosystems. Being lipophilic compounds, PCBs demonstrate the distinguishing sorption/desorption activity taking part in the biogeochemical fluxes via the organic matter particles and sediments. In the framework of the research, the coastal in-situ data on PCB concentration in the water column and sediments are processed, visualized and analyzed. It is concluded that the main sources of PCBs are related to the Danube discharge and resuspension from the shallow-water sediments. Developed 3D numerical model is aimed at simulation of PCB contamination of the water column and sediment. The model integrates the full physics hydrodynamic block as well as modules, which describe detritus transport and transformation and PCB dynamics. Three state variables are simulated in PCB transport module: concentration in solute, on the settling particles of detritus and in the top layer of sediments. PCB adsorption/desorption on detritus; the reversible PCB fluxes at the water-sediment boundary; destruction of detritus are taken into consideration. Formalization of PCB deposition/resuspension in the sediments is adapted from Van Rijn's model of the suspended sediment transport. The model was spun up to reconstruct the short term scenario of the instantaneous PCB release from the St. George Arm of Danube. It has been shown that PCB transport on sinking detritus represents the natural buffer mechanism damping the spreading PCB

  8. Characterization of Methane Degradation and Methane-Degrading Microbes in Alaska Coastal Water

    Energy Technology Data Exchange (ETDEWEB)

    Kirchman, David L. [Univ. of Delaware, Lewes, DE (United States)

    2012-03-29

    The net flux of methane from methane hydrates and other sources to the atmosphere depends on methane degradation as well as methane production and release from geological sources. The goal of this project was to examine methane-degrading archaea and organic carbon oxidizing bacteria in methane-rich and methane-poor sediments of the Beaufort Sea, Alaska. The Beaufort Sea system was sampled as part of a multi-disciplinary expedition (Methane in the Arctic Shelf or MIDAS) in September 2009. Microbial communities were examined by quantitative PCR analyses of 16S rRNA genes and key methane degradation genes (pmoA and mcrA involved in aerobic and anaerobic methane degradation, respectively), tag pyrosequencing of 16S rRNA genes to determine the taxonomic make up of microbes in these sediments, and sequencing of all microbial genes (metagenomes ). The taxonomic and functional make-up of the microbial communities varied with methane concentrations, with some data suggesting higher abundances of potential methane-oxidizing archaea in methane-rich sediments. Sequence analysis of PCR amplicons revealed that most of the mcrA genes were from the ANME-2 group of methane oxidizers. According to metagenomic data, genes involved in methane degradation and other degradation pathways changed with sediment depth along with sulfate and methane concentrations. Most importantly, sulfate reduction genes decreased with depth while the anaerobic methane degradation gene (mcrA) increased along with methane concentrations. The number of potential methane degradation genes (mcrA) was low and inconsistent with other data indicating the large impact of methane on these sediments. The data can be reconciled if a small number of potential methane-oxidizing archaea mediates a large flux of carbon in these sediments. Our study is the first to report metagenomic data from sediments dominated by ANME-2 archaea and is one of the few to examine the entire microbial assemblage potentially involved in

  9. Ecosystem degradation in India

    International Nuclear Information System (INIS)

    Sinha, B.N.

    1990-01-01

    Environmental and ecosystem studies have assumed greater relevance in the last decade of the twentieth century than even before. The urban settlements are becoming over-crowded and industries are increasingly polluting the air, water and sound in our larger metropolises. Degradation of different types of ecosystem are discussed in this book, Ecosystem Degradation in India. The book has been divided into seven chapters: Introduction, Coastal and Delta Ecosystem, River Basin Ecosystem, Mountain Ecosystem, Forest Ecosystem, Urban Ecosystem and the last chapter deals with the Environmental Problems and Planning. In the introduction the environmental and ecosystem degradation problems in India is highlighted as a whole while in other chapters mostly case studies by experts who know their respective terrain very intimately are included. The case study papers cover most part of India and deal with local problems, stretching from east coast to west coast and from Kashmir to Kanyakumari. (author)

  10. PWR degraded core analysis

    International Nuclear Information System (INIS)

    Gittus, J.H.

    1982-04-01

    A review is presented of the various phenomena involved in degraded core accidents and the ensuing transport of fission products from the fuel to the primary circuit and the containment. The dominant accident sequences found in the PWR risk studies published to date are briefly described. Then chapters deal with the following topics: the condition and behaviour of water reactor fuel during normal operation and at the commencement of degraded core accidents; the generation of hydrogen from the Zircaloy-steam and the steel-steam reactions; the way in which the core deforms and finally melts following loss of coolant; debris relocation analysis; containment integrity; fission product behaviour during a degraded core accident. (U.K.)

  11. Motor degradation prediction methods

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, J.R.; Kelly, J.F.; Delzingaro, M.J.

    1996-12-01

    Motor Operated Valve (MOV) squirrel cage AC motor rotors are susceptible to degradation under certain conditions. Premature failure can result due to high humidity/temperature environments, high running load conditions, extended periods at locked rotor conditions (i.e. > 15 seconds) or exceeding the motor`s duty cycle by frequent starts or multiple valve stroking. Exposure to high heat and moisture due to packing leaks, pressure seal ring leakage or other causes can significantly accelerate the degradation. ComEd and Liberty Technologies have worked together to provide and validate a non-intrusive method using motor power diagnostics to evaluate MOV rotor condition and predict failure. These techniques have provided a quick, low radiation dose method to evaluate inaccessible motors, identify degradation and allow scheduled replacement of motors prior to catastrophic failures.

  12. Motor degradation prediction methods

    International Nuclear Information System (INIS)

    Arnold, J.R.; Kelly, J.F.; Delzingaro, M.J.

    1996-01-01

    Motor Operated Valve (MOV) squirrel cage AC motor rotors are susceptible to degradation under certain conditions. Premature failure can result due to high humidity/temperature environments, high running load conditions, extended periods at locked rotor conditions (i.e. > 15 seconds) or exceeding the motor's duty cycle by frequent starts or multiple valve stroking. Exposure to high heat and moisture due to packing leaks, pressure seal ring leakage or other causes can significantly accelerate the degradation. ComEd and Liberty Technologies have worked together to provide and validate a non-intrusive method using motor power diagnostics to evaluate MOV rotor condition and predict failure. These techniques have provided a quick, low radiation dose method to evaluate inaccessible motors, identify degradation and allow scheduled replacement of motors prior to catastrophic failures

  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. Polychlorinated biphenyls and reproductive hormones in female polar bears at Svalbard.

    Science.gov (United States)

    Haave, Marte; Ropstad, Erik; Derocher, Andrew E; Lie, Elisabeth; Dahl, Ellen; Wiig, Øystein; Skaare, Janneche U; Jenssen, Bjørn Munro

    2003-04-01

    High concentrations of polychlorinated biphenyls (PCBs) in polar bears from Svalbard have increased concern for that population's reproductive health. We examined whether there were associations between the plasma concentrations of PCBs and reproductive hormones [progesterone (P4)] and 17 beta-estradiol (E2)] in free-living female polar bears from Svalbard. Concentrations of P4 depended on reproductive status, and concentrations were lowest in females with offspring--females with cubs and females with yearlings. In these females, the P4 concentrations were positively correlated with plasma sigma PCBs (sum of all analyzed polychlorinated biphenyl congeners) concentrations. The sigma PCBs concentrations explained 27% of the variation in the P4 concentrations. There were no correlations between sigma PCBs and E2 and cortisol in any of the groups of polar bears, or between sigma PCBs and P4 in single polar bears. Although the sigma PCBs-P4 relationship in female polar bears with offspring is not evidence per se of a direct cause-effect association, the results indicate that PCBs may affect levels of P4 in polar bear females. There is a clear need to further assess the hormone balance and population health of polar bears at Svalbard.

  15. Azo biphenyl polyurethane: Preparation, characterization and application for optical waveguide switch

    Science.gov (United States)

    Jiang, Yan; Da, Zulin; Qiu, Fengxian; Yang, Dongya; Guan, Yijun; Cao, Guorong

    2018-01-01

    Azo waveguide polymers are of particular interest in the design of materials for applications in optical switch. The aim of this contribution was the synthesis and thermo-optic waveguide switch properties of azo biphenyl polyurethanes. A series of monomers and azo biphenyl polyurethanes (Azo BPU1 and Azo BPU2) were synthesized and characterized by FT-IR, UV-Vis spectroscopy and 1H NMR. The physical and mechanical properties of thin polymer films were measured. The refractive index and thermo-optic coefficient (dn/dT) of polymer films were investigated for TE (transversal electric) polarizations by ATR technique. The transmission loss of film was measured using the Charge Coupled Device digital imaging devices. The results showed the Azo BPU2 containing chiral azobenzene chromophore had higher dn/dT and lower transmission loss. Subsequently, a 1 × 2 Y-branch and 2 × 2 Mach-Zehnder optical switches based on the prepared polymers were designed and simulated. The results showed that the power consumption of all switches was less than 1.0 mW. Compared with 1 × 2 Y-branch optical switch, the 2 × 2 Mach-Zehnder optical switches based on the same polymer have the faster response time, which were about only 1.2 and 2.0 ms, respectively.

  16. Assessing atmospheric concentration of polychlorinated biphenyls by evergreen Rhododendron maximum next to a contaminated stream.

    Science.gov (United States)

    Dang, Viet D; Walters, David M; Lee, Cindy M

    2016-09-01

    Conifers are often used as an air passive sampler, but few studies have focused on the implication of broadleaf evergreens to monitor atmospheric semivolatile organic compounds such as polychlorinated biphenyls (PCBs). In the present study, the authors used Rhododendron maximum (rhododendron) growing next to a contaminated stream to assess atmospheric PCB concentrations. The present study area was located in a rural setting and approximately 2 km downstream of a former capacitor plant. Leaves from the same mature shrubs were collected in late fall 2010 and winter and spring 2011. Polychlorinated biphenyls were detected in the collected leaves, suggesting that rhododendron can be used as air passive samplers in rural areas where active sampling is impractical. Estimated ΣPCB (47 congeners) concentrations in the atmosphere decreased from fall 2010 to spring 2011 with concentration means at 3990 pg m(-3) , 2850 pg m(-3) , and 931 pg m(-3) in fall 2010, winter 2011, and spring 2011, respectively. These results indicate that the atmospheric concentrations at this location continue to be high despite termination of active discharge from the former industrial source. Leaves had a consistent pattern of high concentrations of tetra-CBs and penta-CBs similar to the congener distribution in polyethylene passive samplers deployed in the water column, suggesting that volatilized PCBs from the stream were the primary source of contaminants in rhododendron leaves. Environ Toxicol Chem 2016;35:2192-2198. © 2016 SETAC. © 2016 SETAC.

  17. 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.

  18. Pollutants make rheumatic diseases worse: Facts on polychlorinated biphenyls (PCBs) exposure and rheumatic diseases.

    Science.gov (United States)

    Abella, Vanessa; Pérez, Tamara; Scotece, Morena; Conde, Javier; Pirozzi, Claudio; Pino, Jesús; Lago, Francisca; González-Gay, Miguel Ángel; Mera, Antonio; Gómez, Rodolfo; Gualillo, Oreste

    2016-07-15

    Polychlorinated biphenyls (PCBs) are persistent organic pollutants that bioaccumulate in adipose tissue, disturbing its metabolism and the balance of adipokines, related to obesity. The altering secretion pattern of adipokines from the adipose tissue and the increasing mechanical load in weight-bearing joints presented in obesity condition, are risk factors for osteoarthritis development. The most prevalent rheumatic diseases, osteoarthritis and rheumatoid arthritis, are chronic conditions that target the whole joints, leading to increasing disability and health care cost. The goal of this focused review is to summarize the current knowledge on the role of PCBs in osteoarthritis and rheumatoid arthritis pathogenesis. A PubMed search was managed using keywords as "rheumatic diseases", "polychlorinated biphenyls", "obesity" and "endocrine disruption". The incidence of rheumatoid arthritis has been reported to be increased especially in urban areas in industrialized countries, emphasizing the importance of environment in the pathogenesis of rheumatic diseases. Analysis of two cohorts exposed to PCBs food contamination showed high incidence of arthritis. In addition, PCBs in serum correlated positively with the prevalence of self-reported arthritis. Few studies support the hypothesis that osteoarthritis development could be related to PCBs induction of chondrocytes apoptosis. Evidences have emerged for a relationship between PCBs and development of several types of arthritis. Further research is encouraged to determine the correlation between PCBs exposure and the development of rheumatic diseases. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Antifoam degradation testing

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, D. P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River Ecology Lab. (SREL); Zamecnik, J. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River Ecology Lab. (SREL); Newell, D. D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River Ecology Lab. (SREL); Williams, M. S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River Ecology Lab. (SREL)

    2015-08-20

    This report describes the results of testing to quantify the degradation products resulting from the dilution and storage of Antifoam 747. Antifoam degradation is of concern to the Defense Waste Processing Facility (DWPF) due to flammable decomposition products in the vapor phase of the Chemical Process Cell vessels, as well as the collection of flammable and organic species in the offgas condensate. The discovery that hexamethyldisiloxane is formed from the antifoam decomposition was the basis for a Potential Inadequacy in the Safety Analysis declaration by the DWPF.

  20. Cyanide utilization and degradation by microorganisms.

    Science.gov (United States)

    Knowles, C J

    1988-01-01

    Various microorganisms can produce (cyanogenesis) or degrade cyanide. They degrade cyanide either to detoxify it, or to use it as a source of nitrogen for growth. Significant amounts of cyanide are formed as a secondary metabolite by a wide range of fungi and a few bacteria by decarboxylation of glycine. When cyanide has been formed by the snow mould fungus it is degraded by conversion to carbon dioxide and ammonia via an unknown pathway. In contrast, cyanogenic bacteria either do not further catabolize cyanide or they convert it into beta-cyanoalanine by addition to cysteine or O-acetylserine. Several non-cyanogenic fungi that are pathogens of cyanogenic plants are known to degrade cyanide by hydration to formamide by the enzyme cyanide hydratase. Such fungi can be immobilized and used in packed-cell columns to continuously detoxify cyanide. ICI Biological Products Business market a preparation of spray-dried fungal mycelia, 'CYCLEAR', to detoxify industrial wastes. Novo Industri have also introduced a cyanidase preparation to convert cyanide directly into formate and ammonia. Bacteria have been isolated that use cyanide as a source of nitrogen for growth. Because cyanide, as KCN or NaCN, is toxic for growth, the bacteria (Pseudomonas fluorescens) have to be grown in fed-batch culture with cyanide as the limiting nutrient. Cyanide is converted to carbon dioxide and ammonia (which is then assimilated) by an NADH-linked cyanide oxygenase system.

  1. Aerobic degradation of 4-nitroaniline (4-NA) via novel degradation intermediates by Rhodococcus sp. strain FK48

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Fazlurrahman; Pandey, Janmejay; Vikram, Surendra; Pal, Deepika; Cameotra, Swaranjit Singh, E-mail: ssc@imtech.res.in

    2013-06-15

    Highlights: • This study reports isolation of a novel bacterium capable of mineralizing 4-nitroaniline (4-NA). • This bacterium has been identified as Rhodococcus sp. strain FK48. • Strain FK48 degrades 4-NA via a novel aerobic degradation pathway that involves 4-AP and 1,2,4-BT. • Subsequent degradation proceeds via ring fission and formation of maleylacetate. • This is the first report showing elucidation of catabolic pathway for microbial degradation 4-NA. -- Abstract: An aerobic strain, Rhodococcus sp. strain FK48, capable of growing on 4-nitroaniline (4-NA) as the sole source of carbon, nitrogen, and energy has been isolated from enrichment cultures originating from contaminated soil samples. During growth studies with non- induced cells of FK48 catalyzed sequential denitrification (release of NO{sub 2} substituent) and deamination (release of NH{sub 2} substituent) of 4-NA. However, none of the degradation intermediates could be identified with growth studies. During resting cell studies, 4-NA-induced cells of strain FK48 transformed 4-NA via a previously unknown pathway which involved oxidative hydroxylation leading to formation of 4-aminophenol (4-AP). Subsequent degradation involved oxidated deamination of 4-AP and formation of 1,2,4-benzenetriol (BT) as the major identified terminal aromatic intermediate. Identification of these intermediates was ascertained by HPLC, and GC–MS analyses of the culture supernatants. 4-NA-induced cells of strain FK48 showed positive activity for 1,2,4-benzenetriol dioxygenase in spectrophotometric assay. This is the first conclusive study on aerobic microbial degradation of 4-NA and elucidation of corresponding metabolic pathway.

  2. Drift Degradation Analysis

    International Nuclear Information System (INIS)

    G.H. Nieder-Westermann

    2005-01-01

    The outputs from the drift degradation analysis support scientific analyses, models, and design calculations, including the following: (1) Abstraction of Drift Seepage; (2) Seismic Consequence Abstraction; (3) Structural Stability of a Drip Shield Under Quasi-Static Pressure; and (4) Drip Shield Structural Response to Rock Fall. This report has been developed in accordance with ''Technical Work Plan for: Regulatory Integration Modeling of Drift Degradation, Waste Package and Drip Shield Vibratory Motion and Seismic Consequences'' (BSC 2004 [DIRS 171520]). The drift degradation analysis includes the development and validation of rockfall models that approximate phenomenon associated with various components of rock mass behavior anticipated within the repository horizon. Two drift degradation rockfall models have been developed: the rockfall model for nonlithophysal rock and the rockfall model for lithophysal rock. These models reflect the two distinct types of tuffaceous rock at Yucca Mountain. The output of this modeling and analysis activity documents the expected drift deterioration for drifts constructed in accordance with the repository layout configuration (BSC 2004 [DIRS 172801])

  3. Radiation degradation of silk

    Energy Technology Data Exchange (ETDEWEB)

    Ishida, Kazushige; Kamiishi, Youichi [Textile Research Institute of Gunma, Kiryu, Gunma (Japan); Takeshita, Hidefumi; Yoshii, Fumio; Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2001-03-01

    Silk fibroin powder was prepared from irradiated silk fibroin fiber by means of only physical treatment. Silk fibroin fiber irradiated with an accelerated electron beam in the dose range of 250 - 1000 kGy was pulverized by using a ball mill. Unirradiated silk fibroin fiber was not pulverized at all. But the more irradiation was increased, the more the conversion efficiency from fiber to powder was increased. The conversion efficiency of silk fibroin fiber irradiated 1000 kGy in oxygen was 94%. Silk fibroin powder shows remarkable solubility, which dissolved 57% into water of ambient temperature. It is a very interesting phenomenon that silk fibroin which did not treat with chemicals gets solubility only being pulverized. In order to study mechanism of solubilization of silk fibroin powder, amino acid component of soluble part of silk fibroin powder was analyzed. The more irradiation dose up, the more glycine or alanine degraded, but degradation fraction reached bounds about 50%. Other amino acids were degraded only 20% even at the maximum. To consider crystal construction of silk fibroin, it is suggested that irradiation on silk fibroin fiber selectively degrades glycine and alanine in amorphous region, which makes it possible to pulverize and to dissolve silk fibroin powder. (author)

  4. Degradation and resi

    African Journals Online (AJOL)

    2011-10-25

    Oct 25, 2011 ... Ingeniería, Universidad Nacional de Mar del Plata, J.B. Justo 4302,. 7600 Mar del Plata, Buenos Aires, Argentina. Abstract. 2,4,6-trichlorophenol (TCP) is a toxic compound widespread in the environment, with numerous applications. There are many fungi capable of degrading it, although little attention has ...

  5. Comparison of proposed frameworks for grouping polychlorinated biphenyl congener data applied to a case-control pilot study of prostate cancer

    International Nuclear Information System (INIS)

    Ritchie, Justine M.; Vial, Scott L.; Fuortes, Laurence J.; Robertson, Larry W.; Guo, Haijun; Reedy, Victoria E.; Smith, Elaine M.

    2005-01-01

    Although the commercial synthesis of polychlorinated biphenyls (PCBs) has been banned in the United States for several decades, they are persistent in the environment with exposure mainly being through diet. The biologic and toxic effects of PCBs and their metabolites are due in part to their ability to interact with several cellular and nuclear receptors, thereby altering signaling pathways and gene transcription. These effects include endocrine modulation and disruption. Therefore, the natural history of cancer in tissues expressing these receptors may be modulated by PCB congeners, which are known to have estrogenic, antiestrogenic, and other hormonal effects. Several frameworks for grouping PCB congeners based on these interactions have been proposed. We conducted a hospital-based, case-control pilot study of 58 prostate cancer cases and 99 controls to evaluate the association between the proposed PCB groupings and the risk of prostate cancer. Serum samples were analyzed for a total of 30 PCBs. In multivariate analyses, the odds of prostate cancer among men with the highest concentrations of moderately chlorinated PCBs or PCBs with phenobarbital-like activities (constitutively active receptor (CAR) agonists) was over two times that among men with the lowest concentrations. Increasing trends in risk across the concentration levels were also observed. These results suggest that a higher burden of PCBs that are CAR agonists may be positively associated with an increased risk of prostate cancer and they encourage further research in this area

  6. Polychlorinated biphenyl quinone induces oxidative DNA damage and repair responses: The activations of NHEJ, BER and NER via ATM-p53 signaling axis.

    Science.gov (United States)

    Dong, Hui; Shi, Qiong; Song, Xiufang; Fu, Juanli; Hu, Lihua; Xu, Demei; Su, Chuanyang; Xia, Xiaomin; Song, Erqun; Song, Yang

    2015-07-01

    Our previous studies demonstrated that polychlorinated biphenyl (PCB) quinone induced oxidative DNA damage in HepG2 cells. To promote genomic integrity, DNA damage response (DDR) coordinates cell-cycle transitions, DNA repair and apoptosis. PCB quinone-induced cell cycle arrest and apoptosis have been documented, however, whether PCB quinone insult induce DNA repair signaling is still unknown. In this study, we identified the activation of DDR and corresponding signaling events in HepG2 cells upon the exposure to a synthetic PCB quinone, PCB29-pQ. Our data illustrated that PCB29-pQ induces the phosphorylation of p53, which was mediated by ataxia telangiectasia mutated (ATM) protein kinase. The observed phosphorylated histone H2AX (γ-H2AX) foci and the elevation of 8-hydroxy-2'-deoxyguanosine (8-OHdG) indicated that DDR was stimulated by PCB29-pQ treatment. Additionally, we found PCB29-pQ activates non-homologous end joining (NHEJ), base excision repair (BER) and nucleotide excision repair (NER) signalings. However, these repair pathways are not error-free processes and aberrant repair of DNA damage may cause the potential risk of carcinogenesis and mutagenesis. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. 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

    ... production, handling, and storage of animal feed. 500.45 Section 500.45 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS... the production, handling, and storage of animal feed. (a) Polychlorinated biphenyls (PCB's) represent...

  8. 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