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

    International Nuclear Information System (INIS)

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

    2009-01-01

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

  3. 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...

  4. Biphenyl Modulates the Expression and Function of Respiratory Oxidases in the Polychlorinated-Biphenyls Degrader Pseudomonas pseudoalcaligenes KF707

    Directory of Open Access Journals (Sweden)

    Federica Sandri

    2017-06-01

    Full Text Available Pseudomonas pseudoalcaligenes KF707 is a soil bacterium which is known for its capacity to aerobically degrade harmful organic compounds such as polychlorinated biphenyls (PCBs using biphenyl as co-metabolite. Here we provide the first genetic and functional analysis of the KF707 respiratory terminal oxidases in cells grown with two different carbon sources: glucose and biphenyl. We identified five terminal oxidases in KF707: two c(caa3 type oxidases (Caa3 and Ccaa3, two cbb3 type oxidases (Cbb31 and Cbb32, and one bd type cyanide-insensitive quinol oxidase (CIO. While the activity and expression of both Cbb31 and Cbb32 oxidases was prevalent in glucose grown cells as compared to the other oxidases, the activity and expression of the Caa3 oxidase increased considerably only when biphenyl was used as carbon source in contrast to the Cbb32 oxidase which was repressed. Further, the respiratory activity and expression of CIO was up-regulated in a Cbb31 deletion strain as compared to W.T. whereas the CIO up-regulation was not present in Cbb32 and C(caa3 deletion mutants. These results, together, reveal that both function and expression of cbb3 and caa3 type oxidases in KF707 are modulated by biphenyl which is the co-metabolite needed for the activation of the PCBs-degradation pathway.

  5. Microbial transformation and degradation of polychlorinated biphenyls

    Energy Technology Data Exchange (ETDEWEB)

    Field, Jim A. [Department of Chemical and Environmental Engineering, University of Arizona, PO Box 210011, Tucson, AZ 85721 (United States)], E-mail: jimfield@email.arizona.edu; Sierra-Alvarez, Reyes [Department of Chemical and Environmental Engineering, University of Arizona, PO Box 210011, Tucson, AZ 85721 (United States)

    2008-09-15

    This paper reviews the potential of microorganisms to transform polychlorinated biphenyls (PCBs). In anaerobic environments, higher chlorinated biphenyls can undergo reductive dehalogenation. Meta- and para-chlorines in PCB congeners are more susceptible to dechlorination than ortho-chlorines. Anaerobes catalyzing PCB dechlorination have not been isolated in pure culture but there is strong evidence from enrichment cultures that some Dehalococcoides spp. and other microorganisms within the Chloroflexi phylum can grow by linking the oxidation of H{sub 2} to the reductive dechlorination of PCBs. Lower chlorinated biphenyls can be co-metabolized aerobically. Some aerobes can also grow by utilizing PCB congeners containing only one or two chlorines as sole carbon/energy source. An example is the growth of Burkholderia cepacia by transformation of 4-chlorobiphenyl to chlorobenzoates. The latter compounds are susceptible to aerobic mineralization. Higher chlorinated biphenyls therefore are potentially fully biodegradable in a sequence of reductive dechlorination followed by aerobic mineralization of the lower chlorinated products. - Higher chlorinated biphenyls are potentially fully biodegradable in a sequence of anaerobic reductive dechlorination followed by aerobic mineralization of the lower chlorinated products.

  6. Microbial transformation and degradation of polychlorinated biphenyls

    International Nuclear Information System (INIS)

    Field, Jim A.; Sierra-Alvarez, Reyes

    2008-01-01

    This paper reviews the potential of microorganisms to transform polychlorinated biphenyls (PCBs). In anaerobic environments, higher chlorinated biphenyls can undergo reductive dehalogenation. Meta- and para-chlorines in PCB congeners are more susceptible to dechlorination than ortho-chlorines. Anaerobes catalyzing PCB dechlorination have not been isolated in pure culture but there is strong evidence from enrichment cultures that some Dehalococcoides spp. and other microorganisms within the Chloroflexi phylum can grow by linking the oxidation of H 2 to the reductive dechlorination of PCBs. Lower chlorinated biphenyls can be co-metabolized aerobically. Some aerobes can also grow by utilizing PCB congeners containing only one or two chlorines as sole carbon/energy source. An example is the growth of Burkholderia cepacia by transformation of 4-chlorobiphenyl to chlorobenzoates. The latter compounds are susceptible to aerobic mineralization. Higher chlorinated biphenyls therefore are potentially fully biodegradable in a sequence of reductive dechlorination followed by aerobic mineralization of the lower chlorinated products. - Higher chlorinated biphenyls are potentially fully biodegradable in a sequence of anaerobic reductive dechlorination followed by aerobic mineralization of the lower chlorinated products

  7. Degradation of polychlorinated biphenyls using mesoporous iron-based spinels

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Linyan; Su, Guijin, E-mail: gjsu@rcees.ac.cn; Zhang, Aiqian; Shi, Yali; Xia, Chaobo; Lu, Huijie; Li, Liewu; Liu, Sha; Zheng, Minghui

    2013-10-15

    Highlights: • The NiFe{sub 2}O{sub 4} had the highest activity in degradation of CB-209, followed by Fe{sub 3}O{sub 4}. • Hydroxyl species, organic acids, PCBs and chlorobenzenes were identified as products. • Three degradation reactions and one combination reaction competitively occurred. • Hydrodechlorination of CB-209 was more favored over Fe{sub 3}O{sub 4} than NiFe{sub 2}O{sub 4}. • Oxidation reaction of CB-209 was more favored over NiFe{sub 2}O{sub 4} than Fe{sub 3}O{sub 4}. -- Abstract: A series of mesoporous iron-based spinel materials were synthesized to degrade polychlorinated biphenyls (PCBs), with CB-209 being used as a model compound. The materials were characterized by X-ray powder diffraction (XRD), pore structure analysis, and X-ray photoelectron spectroscopy (XPS). A comparison of the dechlorination efficiencies (DEs) of the materials revealed that NiFe{sub 2}O{sub 4} had the highest DE, followed by Fe{sub 3}O{sub 4}. Newly produced polychlorinated biphenyls, chlorinated benzenes, hydroxyl species and organic acids were detected by gas chromatography–mass spectrometry, high performance liquid chromatography–mass spectrometry and ion chromatograph. Identification of the intermediate products indicates that three degradation pathways, hydrodechlorination, the breakage of C-C bridge bond and oxidative reaction, accompanied by one combination reaction, are competitively occurring over the iron-based spinels. The relative amounts of produced three NoCB isomers were illustrated by the C-Cl BDEs of CB-209 at meta-, para- and ortho-positions, and their energy gap between HOMO and LUMO. The consumption of the reactive oxygen species caused by the transformation of Fe{sub 3}O{sub 4} into Fe{sub 2}O{sub 3} in the Fe{sub 3}O{sub 4} reaction system, and the existence of the highly reactive O{sub 2}{sup −}· species in the NiFe{sub 2}O{sub 4} reaction system, could provide a reason why the oxidation reaction was more favored over NiFe{sub 2}O

  8. Degradation of polychlorinated biphenyls (PCBs) using palladized iron

    International Nuclear Information System (INIS)

    West, O.R.; Liang, L.; Holden, W.L.

    1996-06-01

    Contamination from polychlorinated biphenyls (PCBs) is a persistent problem within the Department of Energy complex, as well as in numerous industrial sites around the US. To date, commercially available technologies for destroying these highly stable compounds involve degradation at elevated temperatures either through incineration or base-catalyzed dehalogenation at 300 degrees C. Since the heating required with these processes substantially increases the costs for treatment of PCB-contaminated wastes, there is a need for finding an alternative approach where PCB can be degraded at ambient temperatures. This report describes the degradation of PCB's utilizing the bimetallic substrate of iron/palladium

  9. 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

  10. Isolation and identification of aerobic polychlorinated biphenyls degrading bacteria

    Directory of Open Access Journals (Sweden)

    Bibi Fatemeh Nabavi

    2013-01-01

    Full Text Available Aims: The purpose of this study was to isolate and identify aerobic polychlorinated biphenyls (PCBs degrading bacteria. Materials and Methods: This study was performed in lab scale aerobic sequencing batch biofilm reactor. Polyurethane foams were used as bio-carrier and synthetic wastewater was prepared with PCBs in transformer oil as the main substrate (20-700 μg/l and acetone as a solvent for PCBs as well as microelements. After achieving to adequate microbial population and acclimation of microorganisms to PCB compounds with high efficiency of PCB removal, identification of degrading microbial species was performed by 16s rRNA gene sequencing of isolated bacteria. Results: Gene sequencing results of the isolated bacteria showed that Rhodococcus spp., Pseudomonas spp., Pseudoxanthomonas spp., Agromyces spp., and Brevibacillus spp. were dominant PCB-degrading bacteria. Conclusion: PCB compounds can be degraded by some microorganisms under aerobic or anaerobic conditions or at least be reduced to low chlorinated congeners, despite their chemical stability and toxicity. Based on the results of the study, five bacterial species capable of degrading PCBs in transformer oil have been identified.

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

    Directory of Open Access Journals (Sweden)

    Jianjun Shuai

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

  12. Isolation and characterization of a novel polychlorinated biphenyl-degrading bacterium, Paenibacillus sp. KBC101

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, M.; Ezaki, S.; Suzuki, N.; Kurane, R. [Kubota Corporation, Ryuugasaki City (Japan). Biotechnology Research Centre

    2005-07-01

    The biphenyl-utilizing bacterial strain KBC101 has been newly isolated from soil. Biphenyl-grown cells of KBC101 efficiently degraded di- to nonachlorobiphenyls. The isolate was identified as Paenibacillus sp. with respect to its 16S rDNA sequence and fatty acid profiles, as well as various biological and physiological characteristics. In the case of highly chlorinated biphenyl (polychlorinated biphenyl; PCB) congeners, the degradation activities of this strain were superior to those of the previously reported strong PCB degrader, Rhodococcus sp. RHA1. Recalcitrant coplanar PCBs, such as 3,4,3',4'-CB, were also efficiently degraded by strain KBC101 cells. This is the first report of a representative of the genus Paenibacillus capable of degrading PCBs. In addition to growth of biphenyl, strain KBC101 could grow on dibenzofuran, xanthene, benzophenone, anthrone, phenanthrene, napthalene, fluorene, fluoranthene, and chrysene as sole sources of carbon and energy. Paenibacillus sp. strain KBC101 presented heterogeneous degradation profiles toward various aromatic compounds. (orig.)

  13. Hybrid pseudomonads engineered by two-step homologous recombination acquire novel degradation abilities toward aromatics and polychlorinated biphenyls

    Energy Technology Data Exchange (ETDEWEB)

    Suenaga, Hikaru [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba (Japan). Bioproduction Research Inst.; Nonaka, Kazuhiko; Goto, Masatoshi [Kyushu Univ., Fukuoka (Japan). Dept. of Bioscience and Biotechnology; Fujihara, Hidehiko; Furukawa, Kensuke [Beppu Univ. (Japan). Dept. of Fermentation and Food Science

    2010-10-15

    Pseudomonas pseudoalcaligenes KF707 possesses a chromosomally encoded bph gene cluster responsible for the catabolism of biphenyl and polychlorinated biphenyls. Previously, we constructed chimeric versions of the bphA1 gene, which encodes a large subunit of biphenyl dioxygenase, by using DNA shuffling between bphA1 genes from P. pseudoalcaligenes KF707 and Burkholderia xenovorans LB400. In this study, we demonstrate replacement of the bphA1 gene with chimeric bphA1 sequence within the chromosomal bph gene cluster by two-step homologous recombination. Notably, some of the hybrid strains acquired enhanced and/or expanded degradation capabilities for specific aromatic compounds, including single aromatic hydrocarbons and polychlorinated biphenyls. (orig.)

  14. Dual Two-Component Regulatory Systems Are Involved in Aromatic Compound Degradation in a Polychlorinated-Biphenyl Degrader, Rhodococcus jostii RHA1 ▿ †

    OpenAIRE

    Takeda, Hisashi; Shimodaira, Jun; Yukawa, Kiyoshi; Hara, Naho; Kasai, Daisuke; Miyauchi, Keisuke; Masai, Eiji; Fukuda, Masao

    2010-01-01

    A Gram-positive polychlorinated-biphenyl (PCB) degrader, Rhodococcus jostii RHA1, degrades PCBs by cometabolism with biphenyl. A two-component BphS1T1 system encoded by bphS1 and bphT1 (formerly bphS and bphT) is responsible for the transcription induction of the five gene clusters, bphAaAbAcAdC1B1, etbAa1Ab1CbphD1, etbAa2Ab2AcD2, etbAdbphB2, and etbD1, which constitute multiple enzyme systems for biphenyl/PCB degradation. The bphS2 and bphT2 genes, which encode BphS2 and BphT2, virtually ide...

  15. Adaptation mechanisms of bacteria during the degradation of polychlorinated biphenyls in the presence of natural and synthetic terpenes as potential degradation inducers

    Energy Technology Data Exchange (ETDEWEB)

    Zoradova-Murinova, Slavomira; Dudasova, Hana; Lukacova, Lucia; Certik, Milan; Dercova, Katarina [Slovak Univ. of Technology, Bratislava (Slovakia). Inst. of Biotechnology and Food Science; Silharova, Katarina; Vrana, Branislav [Water Research Institute, Bratislava (Slovakia)

    2012-06-15

    In this study, we examined the effect of polychlorinated biphenyls (PCBs) in the presence of natural and synthetic terpenes and biphenyl on biomass production, lipid accumulation, and membrane adaptation mechanisms of two PCB-degrading bacterial strains Pseudomonas stutzeri and Burkholderia xenovorans LB400. According to the results obtained, it could be concluded that natural terpenes, mainly those contained in ivy leaves and pine needles, decreased adaptation responses induced by PCBs in these strains. The adaptation processes under investigation included growth inhibition, lipid accumulation, composition of fatty acids, cis/trans isomerization, and membrane saturation. Growth inhibition effect decreased upon addition of these natural compounds to the medium. The amount of unsaturated fatty acids that can lead to elevated membrane fluidity increased in both strains after the addition of the two natural terpene sources. The cells adaptation changes were more prominent in the presence of carvone, limonene, and biphenyl than in the presence of natural terpenes, as indicated by growth inhibition, lipid accumulation, and cis/trans isomerization. Addition of biphenyl and carvone simultaneously with PCBs increased the trans/cis ratio of fatty acids in membrane fractions probably as a result of fluidizing effects of PCBs. This stimulation is more pronounced in the presence of PCBs as a sole carbon source. This suggests that PCBs alone have a stronger effect on bacterial membrane adaptation mechanisms than when added together with biphenyl or natural or synthetic terpenes. (orig.)

  16. Isolation and characterisation of polychlorinated biphenyl (PCB degrading fungi from a historically contaminated soil

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    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

  17. 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.

  18. Photo-fenton degradation of diclofenac: identification of main intermediates and degradation pathway.

    Science.gov (United States)

    Pérez-Estrada, Leónidas A; Malato, Sixto; Gernjak, Wolfgang; Agüera, Ana; Thurman, E Michael; Ferrer, Imma; Fernández-Alba, Amadeo R

    2005-11-01

    In recent years, the presence of pharmaceuticals in the aquatic environment has been of growing interest. These new contaminants are important because many of them are not degraded under the typical biological treatments applied in the wastewater treatment plants and represent a continuous input into the environment. Thus, compounds such as diclofenac are present in surface waters in all Europe and a crucial need for more enhanced technologies that can reduce its presence in the environment has become evident. In this sense, advanced oxidation processes (AOPs) represent a good choice for the treatment of hazardous nonbiodegradable pollutants. This work deals with the solar photodegradation of diclofenac, an antiinflammatory drug, in aqueous solutions by photo-Fenton reaction. A pilot-scale facility using a compound parabolic collector (CPC) reactor was used for this study. Results obtained show rapid and complete oxidation of diclofenac after 60 min, and total mineralization (disappearance of dissolved organic carbon, DOC) after 100 min of exposure to sunlight. Although diclofenac precipitates during the process at low pH, its degradation takes place in the homogeneous phase governed by a precipitation-redissolution-degradation process. Establishment of the reaction pathway was made possible by a thorough analysis of the reaction mixture identifying the main intermediate products generated. Gas chromatography-mass spectrometry (GC/ MS) and liquid chromatography coupled with time-of-flight mass spectrometry (LC/TOF-MS) were used to identify 18 intermediates, in two tentative degradation routes. The main one was based on the initial hydroxylation of the phenylacetic acid moiety in the C-4 position and subsequent formation of a quinone imine derivative that was the starting point for further multistep degradation involving hydroxylation, decarboxylation, and oxidation reactions. An alternative route was based on the transient preservation of the biphenyl amino moiety

  19. Sulfate radical-based degradation of polychlorinated biphenyls: Effects of chloride ion and reaction kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Guo-Dong [Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Dionysiou, Dionysios D. [Environmental Engineering and Science Program, University of Cincinnati, Cincinnati, OH 45221-0071 (United States); Wang, Yu [Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Al-Abed, Souhail R. [National Risk Management Research Laboratory, U.S. Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, OH 45268 (United States); Zhou, Dong-Mei, E-mail: dmzhou@issas.ac.cn [Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer A kinetic model was used to predict the radical species and their distributions. Black-Right-Pointing-Pointer The generated radical species were identified by EPR. Black-Right-Pointing-Pointer The second-order rate constants of sulfate radical with PCBs were determined. - Abstract: Advanced oxidation processes (AOPs) based on sulfate radical (SO{sub 4}{center_dot}{sup -}) have been recently used for soil and groundwater remediation. The presence of chloride ion in natural or wastewater decreases the reactivity of sulfate radical system, but explanations for this behavior were inconsistent, and the mechanisms are poorly understood. Therefore, in this paper we investigated the effect of chloride ion on the degradation of 2,4,4 Prime -CB (PCB28) and biphenyl (BP) by persulfate, based on the produced SO{sub 4}{center_dot}{sup -}. The results showed that the presence of chloride ion greatly inhibited the transformation of PCB28 and BP. Transformation intermediates of BP were monitored, suggesting that the chloride ion can react with SO{sub 4}{center_dot}{sup -} to produce chlorine radical, which reacts with BP to generate chlorinated compounds. To better understand the underlying mechanisms of these processes, a kinetic model was developed for predicting the effect of chloride ion on the types of radical species and their distributions. The results showed that chloride ion could influence the selectivity of radical species and their distribution, and increase the concentration of the sum of radical species. In addition, the second-order rate constants of sulfate radical with PCBs were determined, and quantum-chemical descriptors were introduced to predict the rate constants of other PCBs based on our experimental data.

  20. 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

  1. Construction and applications of DNA probes for detection of polychlorinated biphenyl-degrading genotypes in toxic organic-contaminated soil environments

    International Nuclear Information System (INIS)

    Walia, S.; Khan, A.; Rosenthal, N.

    1990-01-01

    Several DNA probes for polychlorinated biphenyl (PCB)-degrading genotypes were constructed from PCB-degrading bacteria. These laboratory-engineered DNA probes were used for the detection, enumeration, and isolation of specific bacteria degrading PCBs. Dot blot analysis of purified DNA from toxic organic chemical-contaminated soil bacterial communities showed positive DNA-DNA hybridization with a 32P-labeled DNA probe (pAW6194, cbpABCD). Less than 1% of bacterial colonies isolated from garden topsoil and greater than 80% of bacteria isolated from PCB-contaminated soils showed DNA homologies with 32P-labeled DNA probes. Some of the PCB-degrading bacterial isolates detected by the DNA probe method did not show biphenyl clearance. The DNA probe method was found to detect additional organisms with greater genetic potential to degrade PCBs than the biphenyl clearance method did. Results from this study demonstrate the usefulness of DNA probes in detecting specific PCB-degrading bacteria, abundance of PCB-degrading genotypes, and genotypic diversity among PCB-degrading bacteria in toxic chemical-polluted soil environments. We suggest that the DNA probe should be used with caution for accurate assessment of PCB-degradative capacity within soils and further recommend that a combination of DNA probe and biodegradation assay be used to determine the abundance of PCB-degrading bacteria in the soil bacterial community

  2. 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.

  3. 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.

  4. Impact of size and sorption on degradation of trichloroethylene and polychlorinated biphenyls by nano-scale zerovalent iron

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, Elijah J. [Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Pinto, Roger A. [Department of Chemical Engineering, University of Michigan, Ann Arbor (United States); Shi, Xiangyang [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, Shanghai 201620 (China); College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620 (China); Huang, Qingguo, E-mail: qhuang@uga.edu [Department of Crop and Soil Sciences, University of Georgia, Griffin, GA 30223 (United States)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer nZVIs were synthesized using a layer-by-layer or poly(acrylic acid) stabilization approach. Black-Right-Pointing-Pointer These nZVIs were used to degrade TCE and PCB. Black-Right-Pointing-Pointer nZVI coatings impacted reactivity by altering pollutants/particle interactions. Black-Right-Pointing-Pointer Smaller nZVI particle size led to greater reactivity. - Abstract: Nano-scale zerovalent iron (nZVI) has been studied in recent years for environmental remediation applications such as the degradation of chlorinated organic contaminants. To overcome limitations related to the transport of nZVI, it is becoming common to add a polymer stabilizer to limit aggregation and enhance the particle reactivity. Another method investigated to enhance particle reactivity has been to limit particle size through novel synthesis techniques. However, the relative impacts of particle size and interactions of the chemicals with the coatings are not yet well understood. The purpose of this study was to investigate the mechanisms of particle size and polymer coating or polyelectrolyte multilayer (PEM) synthesis conditions on degradation of two common chlorinated contaminants: trichloroethylene (TCE) and polychlorinated biphenyls (PCBs). This was accomplished using two different synthesis techniques, a layer-by-layer approach at different pH values or iron reduction in the presence of varying concentrations of poly(acrylic acid). nZVI produced by both techniques yielded higher degradation rates than a traditional approach. The mechanistic investigation indicated that hydrophobicity and sorption to the multilayer impacts the availability of the hydrophobic compound to the nZVI and that particle size also had a large role with smaller particles having stronger dechlorination rates.

  5. 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.

  6. Vitamin C Degradation Products and Pathways in the Human Lens*

    OpenAIRE

    Nemet, Ina; Monnier, Vincent M.

    2011-01-01

    Vitamin C and its degradation products participate in chemical modifications of proteins in vivo through non-enzymatic glycation (Maillard reaction) and formation of different products called advanced glycation end products. Vitamin C levels are particularly high in selected tissues, such as lens, brain and adrenal gland, and its degradation products can inflict substantial protein damage via formation of advanced glycation end products. However, the pathways of in vivo vitamin C degradation ...

  7. Vitamin C degradation products and pathways in the human lens.

    Science.gov (United States)

    Nemet, Ina; Monnier, Vincent M

    2011-10-28

    Vitamin C and its degradation products participate in chemical modifications of proteins in vivo through non-enzymatic glycation (Maillard reaction) and formation of different products called advanced glycation end products. Vitamin C levels are particularly high in selected tissues, such as lens, brain and adrenal gland, and its degradation products can inflict substantial protein damage via formation of advanced glycation end products. However, the pathways of in vivo vitamin C degradation are poorly understood. Here we have determined the levels of vitamin C oxidation and degradation products dehydroascorbic acid, 2,3-diketogulonic acid, 3-deoxythreosone, xylosone, and threosone in the human lens using o-phenylenediamine to trap both free and protein-bound adducts. In the protein-free fraction and water-soluble proteins (WSP), all five listed degradation products were identified. Dehydroascorbic acid, 2,3-diketogulonic acid, and 3-deoxythreosone were the major products in the protein-free fraction, whereas in the WSP, 3-deoxythreosone was the most abundant measured dicarbonyl. In addition, 3-deoxythreosone in WSP showed positive linear correlation with age (p degradation product bound to human lens proteins provides in vivo evidence for the non-oxidative pathway of dehydroascorbate degradation into erythrulose as a major pathway for vitamin C degradation in vivo.

  8. Protein degradation pathways in Parkinson's disease: curse or blessing.

    Science.gov (United States)

    Ebrahimi-Fakhari, Darius; Wahlster, Lara; McLean, Pamela J

    2012-08-01

    Protein misfolding, aggregation and deposition are common disease mechanisms in many neurodegenerative diseases including Parkinson's disease (PD). Accumulation of damaged or abnormally modified proteins may lead to perturbed cellular function and eventually to cell death. Thus, neurons rely on elaborated pathways of protein quality control and removal to maintain intracellular protein homeostasis. Molecular chaperones, the ubiquitin-proteasome system (UPS) and the autophagy-lysosomal pathway (ALP) are critical pathways that mediate the refolding or removal of abnormal proteins. The successive failure of these protein degradation pathways, as a cause or consequence of early pathological alterations in vulnerable neurons at risk, may present a key step in the pathological cascade that leads to spreading neurodegeneration. A growing number of studies in disease models and patients have implicated dysfunction of the UPS and ALP in the pathogenesis of Parkinson's disease and related disorders. Deciphering the exact mechanism by which the different proteolytic systems contribute to the elimination of pathogenic proteins, like α-synuclein, is therefore of paramount importance. We herein review the role of protein degradation pathways in Parkinson's disease and elaborate on the different contributions of the UPS and the ALP to the clearance of altered proteins. We examine the interplay between different degradation pathways and provide a model for the role of the UPS and ALP in the evolution and progression of α-synuclein pathology. With regards to exciting recent studies we also discuss the putative potential of using protein degradation pathways as novel therapeutic targets in Parkinson's disease.

  9. 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...

  10. 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.

  11. 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

  12. Trichloroethylene degradation by two independent aromatic-degrading pathways in Alcaligenes eutrophus JMP134.

    OpenAIRE

    Harker, A R; Kim, Y

    1990-01-01

    The bacterium Alcaligenes eutrophus JMP134(pJP4) degrades trichloroethylene (TCE) by a chromosomal phenol-dependent pathway and by the plasmid-encoded 2,4-dichlorophenoxyacetic acid pathway. The two pathways were independent and exhibited different rates of removal and capacities for quantity of TCE removed. The phenol-dependent pathway was more rapid (0.2 versus 0.06 nmol of TCE removed per min per mg of protein) and consumed all detectable TCE. The 2,4-dichlorophenoxyacetic acid-dependent p...

  13. Degradation of Nicotine in Chlorinated Water: Pathways and ...

    Science.gov (United States)

    Report The objective of the study is to illustrate how drinking water would affect alkaloid pesticides, and to address the issue by (a) investigating the fate of nicotine in chlorinated drinking water and deionized water, (b) determining the reaction rate and pathway of the reaction between nicotine and aqueous chlorine, (c) identifying nicotine’s degradation products, and (d) providing data that can be used to assess the potential threat from nicotine in drinking water.

  14. 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.

  15. Culture-dependent and culture-independent characterization of potentially functional biphenyl-degrading bacterial community in response to extracellular organic matter from Micrococcus luteus.

    Science.gov (United States)

    Su, Xiao-Mei; Liu, Yin-Dong; Hashmi, Muhammad Zaffar; Ding, Lin-Xian; Shen, Chao-Feng

    2015-05-01

    Biphenyl (BP)-degrading bacteria were identified to degrade various polychlorinated BP (PCB) congers in long-term PCB-contaminated sites. Exploring BP-degrading capability of potentially useful bacteria was performed for enhancing PCB bioremediation. In the present study, the bacterial composition of the PCB-contaminated sediment sample was first investigated. Then extracellular organic matter (EOM) from Micrococcus luteus was used to enhance BP biodegradation. The effect of the EOM on the composition of bacterial community was investigated by combining with culture-dependent and culture-independent methods. The obtained results indicate that Proteobacteria and Actinobacteria were predominant community in the PCB-contaminated sediment. EOM from M. luteus could stimulate the activity of some potentially difficult-to-culture BP degraders, which contribute to significant enhancement of BP biodegradation. The potentially difficult-to-culture bacteria in response to EOM addition were mainly Rhodococcus and Pseudomonas belonging to Gammaproteobacteria and Actinobacteria respectively. This study provides new insights into exploration of functional difficult-to-culture bacteria with EOM addition and points out broader BP/PCB degrading, which could be employed for enhancing PCB-bioremediation processes. © 2015 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  16. 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 ...

  17. 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

  18. 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

  19. Proteogenomic Characterization of Monocyclic Aromatic Hydrocarbon Degradation Pathways in the Aniline-Degrading Bacterium Burkholderia sp. K24.

    Directory of Open Access Journals (Sweden)

    Sang-Yeop Lee

    Full Text Available Burkholderia sp. K24, formerly known as Acinetobacter lwoffii K24, is a soil bacterium capable of utilizing aniline as its sole carbon and nitrogen source. Genomic sequence analysis revealed that this bacterium possesses putative gene clusters for biodegradation of various monocyclic aromatic hydrocarbons (MAHs, including benzene, toluene, and xylene (BTX, as well as aniline. We verified the proposed MAH biodegradation pathways by dioxygenase activity assays, RT-PCR, and LC/MS-based quantitative proteomic analyses. This proteogenomic approach revealed four independent degradation pathways, all converging into the citric acid cycle. Aniline and p-hydroxybenzoate degradation pathways converged into the β-ketoadipate pathway. Benzoate and toluene were degraded through the benzoyl-CoA degradation pathway. The xylene isomers, i.e., o-, m-, and p-xylene, were degraded via the extradiol cleavage pathways. Salicylate was degraded through the gentisate degradation pathway. Our results show that Burkholderia sp. K24 possesses versatile biodegradation pathways, which may be employed for efficient bioremediation of aniline and BTX.

  20. Proteogenomic Characterization of Monocyclic Aromatic Hydrocarbon Degradation Pathways in the Aniline-Degrading Bacterium Burkholderia sp. K24

    Science.gov (United States)

    Yun, Sung Ho; Choi, Chi-Won; Yi, Yoon-Sun; Kim, Jonghyun; Chung, Young-Ho; Park, Edmond Changkyun; Kim, Seung Il

    2016-01-01

    Burkholderia sp. K24, formerly known as Acinetobacter lwoffii K24, is a soil bacterium capable of utilizing aniline as its sole carbon and nitrogen source. Genomic sequence analysis revealed that this bacterium possesses putative gene clusters for biodegradation of various monocyclic aromatic hydrocarbons (MAHs), including benzene, toluene, and xylene (BTX), as well as aniline. We verified the proposed MAH biodegradation pathways by dioxygenase activity assays, RT-PCR, and LC/MS-based quantitative proteomic analyses. This proteogenomic approach revealed four independent degradation pathways, all converging into the citric acid cycle. Aniline and p-hydroxybenzoate degradation pathways converged into the β-ketoadipate pathway. Benzoate and toluene were degraded through the benzoyl-CoA degradation pathway. The xylene isomers, i.e., o-, m-, and p-xylene, were degraded via the extradiol cleavage pathways. Salicylate was degraded through the gentisate degradation pathway. Our results show that Burkholderia sp. K24 possesses versatile biodegradation pathways, which may be employed for efficient bioremediation of aniline and BTX. PMID:27124467

  1. 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

    2016-02-01

    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 13C-biphenyl (unchlorinated analogue of PCBs) and/or 13C-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.

  2. 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.

  3. 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.

  4. 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.

  5. Tetracycline degradation by ozonation in the aqueous phase: Proposed degradation intermediates and pathway

    International Nuclear Information System (INIS)

    Khan, M. Hammad; Bae, Hyokwan; Jung, Jin-Young

    2010-01-01

    During the ozonation of tetracycline (TC) in aqueous media at pHs 2.2 and 7.0, the effects of pH variations, protonation and dissociation of functional groups and variation in free radical exposure were investigated to elucidate the transformation pathway. Liquid chromatography-triple quadrupole mass spectrometry detected around 15 ozonation products, and uncovered their production and subsequent degradation patterns. During ozonation at pH 2.2, the TC degradation pathway was proposed on the basis of the structure, ozonation chemistry and mass spectrometry data of TC. Ozonation of TC at the C11a-C12 and C2-C3 double bonds, aromatic ring and amino group generated products of m/z 461, 477, 509 and 416, respectively. Further ozonation at the above mentioned sites gave products of m/z 432, 480, 448, 525 and 496. The removal of TOC reached a maximum of ∼40% after 2 h of ozonation, while TC was completely removed within 4-6 min at both pHs. The low TOC removal efficiency might be due to the generation of recalcitrant products and the low ozone supply for high TC concentration. Ozonation decreased the acute toxicity of TC faster at pH 7.0 than pH 2.2, but the maximum decrease was only about 40% at both pHs after 2 h of ozonation. In this study, attempts were made to understand the correlation between the transformation products, pathway, acute toxicity and quantity of residual organics in solution. Overall, ozonation was found to be a promising process for removing TC and the products initially generated.

  6. 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...

  7. 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.

  8. 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.

  9. MAPKs are essential upstream signaling pathways in proteolytic cartilage degradation--divergence in pathways leading to aggrecanase and MMP-mediated articular cartilage degradation

    DEFF Research Database (Denmark)

    Sondergaard, B-C; Schultz, N; Madsen, S H

    2010-01-01

    Matrix metalloproteinases (MMPs) and aggrecanases are essential players in cartilage degradation. However, the signaling pathways that results in MMP and/or aggrecanase synthesis and activation are not well understood. We investigated the molecular events leading to MMP- and aggrecanase-mediated ......Matrix metalloproteinases (MMPs) and aggrecanases are essential players in cartilage degradation. However, the signaling pathways that results in MMP and/or aggrecanase synthesis and activation are not well understood. We investigated the molecular events leading to MMP- and aggrecanase......-mediated cartilage degradation....

  10. The metabolism of biphenyl

    International Nuclear Information System (INIS)

    Meyer, T.; Aarbakke, J.; Scheline, R.R.

    1976-01-01

    The metabolic disposition of 14 C-biphenyl in the rat was studied by liquid scintillation counting. The rats were given an oral dose of 14 C-biphenyl (100 mg/kg, 0.7-1.0 μci) and the total excretion of radioactivity after 96 hrs was 92.2% of the dose. Urinary excretion accounted for 84.8% and faecal excretion for 7.3% of the dose. Most of this radioactivity, 75.8% and 5.8% respectively, was excreted within 24 hrs. Only trace amounts of 14 CO 2 were detected in the expired air and 0.6% of the dose was found to be still present in the rats 96 hrs after biphenyl administration. Extraction and fractionation of the 24 hrs urine samples showed that the largest fraction (nearly 30% of the dose) consisted of conjugated phenolic metabolites. Acidic metabolites accounted for a quarter of the dose and the low levels of expired 14 CO 2 indicated that these were not products resulting from extensive degradation and decarboxylation. (author)

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

    DEFF Research Database (Denmark)

    Månsson, Mats David Joakim

    in a process termed ER-associated degradation (ERAD). This mechanism proceeds through four steps involving recognition, dislocation, ubiquitination and proteasomal degradation. This report describes a high-throughput screening method for identification of hitherto unknown pathways for degradation. We present...... 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...

  12. Pathway and rate-limiting step of glyphosate degradation by Aspergillus oryzae A-F02.

    Science.gov (United States)

    Fu, Gui-Ming; Chen, Yan; Li, Ru-Yi; Yuan, Xiao-Qiang; Liu, Cheng-Mei; Li, Bin; Wan, Yin

    2017-09-14

    Aspergillus oryzae A-F02, a glyphosate-degrading fungus, was isolated from an aeration tank in a pesticide factory. The pathway and rate-limiting step of glyphosate (GP) degradation were investigated through metabolite analysis. GP, aminomethylphosphonic acid (AMPA), and methylamine were detected in the fermentation liquid of A. oryzae A-F02, whereas sarcosine and glycine were not. The pathway of GP degradation in A. oryzae A-F02 was revealed: GP was first degraded into AMPA, which was then degraded into methylamine. Finally, methylamine was further degraded into other products. Investigating the effects of the exogenous addition of substrates and metabolites showed that the degradation of GP to AMPA is the rate-limiting step of GP degradation by A. oryzae A-F02. In addition, the accumulation of AMPA and methylamine did not cause feedback inhibition in GP degradation. Results showed that degrading GP to AMPA was a crucial step in the degradation of GP, which determines the degradation rate of GP by A. oryzae A-F02.

  13. 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...

  14. 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.

  15. 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.

  16. 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.

  17. 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...... revealed the interaction network of the main 3'-5' RNA degradation machinery – the RNA exosome complex. One of the key findings was the identification and characterisation of the Nuclear Exosome Targeting (NEXT) complex, important for nuclear functions of the exosome. Michal Lubas also studied the role...

  18. Synergetic effect of alkaline earth metal oxides and iron oxides on the degradation of hexachlorobenzene and its degradation pathway.

    Science.gov (United States)

    Su, Guijin; Liu, Yexuan; Huang, Linyan; Shi, Yali; Zhang, Aiqian; Zhang, Lixia; Liu, Wenbin; Gao, Lirong; Zheng, Minghui

    2013-01-01

    The degradation of hexachlorobenzene (HCB) was carried out over physical mixtures of a series of alkaline earth metal oxides (MO: M=Mg, Ca, Sr, Ba) and iron oxides with different crystal types (Fe(x)O(y):Fe(2)O(3) or Fe(3)O(4)) at 300°C. These physical mixtures all showed a synergetic effect toward the degradation of HCB. A range of degradation products were identified by various methods, including tri- to penta-chlorobenzenes by gas chromatography/mass spectrometry (GC-MS), tri- to penta-chlorophenols, tetrachlorocatechol (TCC) and tetrachlorohydroquinone (TCHQ) by GC-MS after derivatization, and formic and acetic acids by ion chromatography. Two degradation pathways, hydrodechlorination and oxidative degradation, appear to occur competitively. However, more sequential chlorinated benzene and phenol congeners were formed over mixed MO/Fe(3)O(4) than over mixed MO/Fe(2)O(3) under the same conditions. The oxidative reaction dominated over mixed MO/Fe(2)O(3) and was promoted as the major reaction by the synergetic effect, while both the oxidative and hydrodechlorination reactions were important over mixed MO/Fe(3)O(4), and both pathways are remarkably promoted by the synergetic effect. The enhanced hydrodechlorination may be attributed to free electrons generated by the transformation of Fe(3)O(4) into Fe(2)O(3), and hydrogen provided by water adsorbed on the MO. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. 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

  20. Characterization of the novel dimethyl sulfide-degrading bacterium Alcaligenes sp. SY1 and its biochemical degradation pathway

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yiming; Qiu, Jiguo; Chen, Dongzhi; Ye, Jiexu; Chen, Jianmeng, E-mail: jchen@zjut.edu.cn

    2016-03-05

    Highlights: • A novel efficient DMS-degrading bacterium Alcaligenes sp. SY1 was identified. • A RSM was applied to optimize incubation condition of Alcaligenes sp. SY1. • SIP was applied as C{sup 13} labelled DMS to trace intermediates during DMS degradation. • Kinetics of DMS degradation via batch experiment was revealed. • Carbon and sulfur balance were analyzed during DMS degradation process. - Abstract: Recently, the biodegradation of volatile organic sulfur compounds (VOSCs) has become a burgeoning field, with a growing focus on the reduction of VOSCs. The reduction of VOSCs encompasses both organic emission control and odor control. Herein, Alcaligenes sp. SY1 was isolated from active sludge and found to utilize dimethyl sulfide (DMS) as a growth substrate in a mineral salt medium. Response surface methodology (RSM) analysis was applied to optimize the incubation conditions. The following conditions for optimal degradation were identified: temperature 27.03 °C; pH 7.80; inoculum salinity 0.84%; and initial DMS concentration 1585.39 μM. Under these conditions, approximately 99% of the DMS was degraded within 30 h of incubation. Two metabolic compounds were detected and identified by gas chromatography–mass spectrometry (GC–MS): dimethyl disulfide (DMDS) and dimethyl trisulfide (DMTS). The DMS degradation kinetics for different concentrations were evaluated using the Haldane–Andrews model and the pseudo first-order model. The maximum specific growth rate and degradation rate of Alcaligenes sp. SY1 were 0.17 h{sup −1} and 0.63 gs gx{sup −1} h{sup −1}. A possible degradation pathway is proposed, and the results suggest that Alcaligenes sp. SY1 has the potential to control odor emissions under aerobic conditions.

  1. Characterization of a Pyrethroid-Degrading Pseudomonas fulva Strain P31 and Biochemical Degradation Pathway of D-Phenothrin

    Directory of Open Access Journals (Sweden)

    Jingjing Yang

    2018-05-01

    Full Text Available D-phenothrin is one of the most popular pyrethroid insecticides for its broad spectrum and high insecticidal activity. However, continuous use of D-phenothrin has resulted in serious environmental contamination and raised public concern about its impact on human health. Biodegradation of D-phenothrin has never been investigated and its metabolic behaviors remain unknown. Here, a novel bacterial strain P31 was isolated from active sludge, which completely degraded (100% D-phenothrin at 50 mg⋅L-1 in 72 h. Based on the morphology, 16S rRNA gene and Biolog tests, the strain was identified as Pseudomonas fulva. Biodegradation conditions were optimized as 29.5°C and pH 7.3 by utilizing response surface methodology. Strain P31 depicted high tolerance and strong D-phenothrin degradation ability through hydrolysis pathway. Strain P31 degraded D-phenothrin at inhibition constant (Ki of 482.1673 mg⋅L-1 and maximum specific degradation constant (qmax of 0.0455 h-1 whereas critical inhibitor concentration remained as 41.1189 mg⋅L-1. The 3-Phenoxybenzaldehyde and 1,2-benzenedicarboxylic butyl dacyl ester were identified as the major intermediate metabolites of D-phenothrin degradation pathway through high-performance liquid chromatography and gas chromatography-mass spectrometry. Bioaugmentation of D-phenothrin-contaminated soils with strain P31 dramatically enhanced its degradation, and over 75% of D-phenothrin was removed from soils within 10 days. Moreover, the strain illustrated a remarkable capacity to degrade other synthetic pyrethroids, including permethrin, cyhalothrin, β-cypermethrin, deltamethrin, fenpropathrin, and bifenthrin, exhibiting great potential in bioremediation of pyrethroid-contaminated environment.

  2. 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...

  3. 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.

  4. 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.

  5. Robust Ordering of Anaphase Events by Adaptive Thresholds and Competing Degradation Pathways.

    Science.gov (United States)

    Kamenz, Julia; Mihaljev, Tamara; Kubis, Armin; Legewie, Stefan; Hauf, Silke

    2015-11-05

    The splitting of chromosomes in anaphase and their delivery into the daughter cells needs to be accurately executed to maintain genome stability. Chromosome splitting requires the degradation of securin, whereas the distribution of the chromosomes into the daughter cells requires the degradation of cyclin B. We show that cells encounter and tolerate variations in the abundance of securin or cyclin B. This makes the concurrent onset of securin and cyclin B degradation insufficient to guarantee that early anaphase events occur in the correct order. We uncover that the timing of chromosome splitting is not determined by reaching a fixed securin level, but that this level adapts to the securin degradation kinetics. In conjunction with securin and cyclin B competing for degradation during anaphase, this provides robustness to the temporal order of anaphase events. Our work reveals how parallel cell-cycle pathways can be temporally coordinated despite variability in protein concentrations. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. 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.

  7. 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.

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

    Science.gov (United States)

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

    2013-09-15

    A novel dual-tank photoelectrochemical catalytic reactor was designed to investigate the degradation pathway of malachite green. A thermally formed TiO₂/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. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Degradation of oxcarbazepine by UV-activated persulfate oxidation: kinetics, mechanisms, and pathways.

    Science.gov (United States)

    Bu, Lingjun; Zhou, Shiqing; Shi, Zhou; Deng, Lin; Li, Guangchao; Yi, Qihang; Gao, Naiyun

    2016-02-01

    The degradation kinetics and mechanism of the antiepileptic drug oxcarbazepine (OXC) by UV-activated persulfate oxidation were investigated in this study. Results showed that UV/persulfate (UV/PS) process appeared to be more effective in degrading OXC than UV or PS alone. The OXC degradation exhibited a pseudo-first order kinetics pattern and the degradation rate constants (k obs) were affected by initial OXC concentration, PS dosage, initial pH, and humic acid concentration to different degrees. It was found that low initial OXC concentration, high persulfate dosage, and initial pH enhanced the OXC degradation. Additionally, the presence of humic acid in the solution could greatly inhibit the degradation of OXC. Moreover, hydroxyl radical (OH•) and sulfate radical (SO4 (-)••) were identified to be responsible for OXC degradation and SO4 (-)• made the predominant contribution in this study. Finally, major intermediate products were identified and a preliminary degradation pathway was proposed. Results demonstrated that UV/PS system is a potential technology to control the water pollution caused by emerging contaminants such as OXC.

  10. A second pathway to degrade pyrimidine nucleic acid precursors in eukaryotes

    DEFF Research Database (Denmark)

    Andersen, Gorm; Bjornberg, Olof; Polakova, Silvia

    2008-01-01

    Pyrimidine bases are the central precursors for RNA and DNA, and their intracellular pools are determined by de novo, salvage and catabolic pathways. In eukaryotes, degradation of uracil has been believed to proceed only via the reduction to dihydrouracil. Using a yeast model, Saccharomyces kluyv...... of the eukaryotic or prokaryotic genes involved in pyrimidine degradation described to date.......Pyrimidine bases are the central precursors for RNA and DNA, and their intracellular pools are determined by de novo, salvage and catabolic pathways. In eukaryotes, degradation of uracil has been believed to proceed only via the reduction to dihydrouracil. Using a yeast model, Saccharomyces......, respectively. The gene products of URC1 and URC4 are highly conserved proteins with so far unknown functions and they are present in a variety of prokaryotes and fungi. In bacteria and in some fungi, URC1 and URC4 are linked on the genome together with the gene for uracil phosphoribosyltransferase (URC6). Urc1...

  11. A novel pathway for nicotine degradation by Aspergillus oryzae 112822 isolated from tobacco leaves.

    Science.gov (United States)

    Meng, Xiang Jing; Lu, Li Li; Gu, Guo Feng; Xiao, Min

    2010-09-01

    An efficient nicotine-degrading fungus was isolated from tobacco leaves and identified as Aspergillus oryzae 112822 based on morphological characteristics and sequence analysis of 18S rDNA, 5.8S rDNA and the internal transcribed spacer (5.8S-ITS region). When the strain was cultured in a medium with tobacco leaf extract for 40 h, the maximum amount of cell growth was 3.6 g l(-1) and nicotine degradation was 2.19 g l(-1). The intermediates of nicotine degradation by resting cells were isolated by preparative TLC or semi-preparative HPLC, and identified by TLC, MS, NMR, Fourier-transform (FT)-IR and GC-MS analysis. The pathway for nicotine degradation in A. oryzae 112822 was proposed to be from nicotine to 2,3-dihydroxypyridine through the intermediates nornicotine, myosmine, N-methylnicotinamide and 2-hydroxy-N-methylnicotinamide. The ring of 2,3-dihydroxypyridine was opened between the 2- and 3-hydroxy positions to yield succinic acid. N-methylnicotinamide and 2,3-dihydroxypyridine were satisfactorily verified as metabolites of nicotine degradation. This is the first elucidation of a pathway for nicotine degradation in fungi. Copyright 2010 Elsevier Masson SAS. All rights reserved.

  12. 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

  13. Dysfunction of different cellular degradation pathways contributes to specific β-amyloid42-induced pathologies.

    Science.gov (United States)

    Ji, Xuan-Ru; Cheng, Kuan-Chung; Chen, Yu-Ru; Lin, Tzu-Yu; Cheung, Chun Hei Antonio; Wu, Chia-Lin; Chiang, Hsueh-Cheng

    2018-03-01

    The endosomal-lysosomal system (ELS), autophagy, and ubiquitin-proteasome system (UPS) are cellular degradation pathways that each play a critical role in the removal of misfolded proteins and the prevention of the accumulation of abnormal proteins. Recent studies on Alzheimer's disease (AD) pathogenesis have suggested that accumulation of aggregated β-amyloid (Aβ) peptides in the AD brain results from a dysfunction in these cellular clearance systems. However, the specific roles of these pathways in the removal of Aβ peptides and the pathogenesis underlying AD are unclear. Our in vitro and in vivo genetic approaches revealed that ELS mainly removed monomeric β-amyloid42 (Aβ42), while autophagy and UPS clear oligomeric Aβ42. Although overproduction of phosphatidylinositol 4-phosphate-5 increased Aβ42 clearance, it reduced the life span of Aβ42 transgenic flies. Our behavioral studies further demonstrated impaired autophagy and UPS-enhanced Aβ42-induced learning and memory deficits, but there was no effect on Aβ42-induced reduction in life span. Results from genetic fluorescence imaging showed that these pathways were damaged in the following order: UPS, autophagy, and finally ELS. The results of our study demonstrate that different degradation pathways play distinct roles in the removal of Aβ42 aggregates and in disease progression. These findings also suggest that pharmacologic treatments that are designed to stimulate cellular degradation pathways in patients with AD should be used with caution.-Ji, X.-R., Cheng, K.-C., Chen, Y.-R., Lin, T.-Y., Cheung, C. H. A., Wu, C.-L., Chiang, H.-C. Dysfunction of different cellular degradation pathways contributes to specific β-amyloid42-induced pathologies.

  14. Thermic decomposition of biphenyl; Decomposition thermique du biphenyle

    Energy Technology Data Exchange (ETDEWEB)

    Lutz, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1966-03-01

    Liquid and vapour phase pyrolysis of very pure biphenyl obtained by methods described in the text was carried out at 400 C in sealed ampoules, the fraction transformed being always less than 0.1 per cent. The main products were hydrogen, benzene, terphenyls, and a deposit of polyphenyls strongly adhering to the walls. Small quantities of the lower aliphatic hydrocarbons were also found. The variation of the yields of these products with a) the pyrolysis time, b) the state (gas or liquid) of the biphenyl, and c) the pressure of the vapour was measured. Varying the area and nature of the walls showed that in the absence of a liquid phase, the pyrolytic decomposition takes place in the adsorbed layer, and that metallic walls promote the reaction more actively than do those of glass (pyrex or silica). A mechanism is proposed to explain the results pertaining to this decomposition in the adsorbed phase. The adsorption seems to obey a Langmuir isotherm, and the chemical act which determines the overall rate of decomposition is unimolecular. (author) [French] Du biphenyle tres pur, dont la purification est decrite, est pyrolyse a 400 C en phase vapeur et en phase liquide dans des ampoules scellees sous vide, a des taux de decomposition n'ayant jamais depasse 0,1 pour cent. Les produits provenant de la pyrolyse sont essentiellement: l' hydrogene, le benzene, les therphenyles, et un depot de polyphenyles adherant fortement aux parois. En plus il se forme de faibles quantites d'hydrocarbures aliphatiques gazeux. On indique la variation des rendements des differents produits avec la duree de pyrolyse, l'etat gazeux ou liquide du biphenyle, et la pression de la vapeur. Variant la superficie et la nature des parois, on montre qu'en absence de liquide la pyrolyse se fait en phase adsorbee. La pyrolyse est plus active au contact de parois metalliques que de celles de verres (pyrex ou silice). A partir des resultats experimentaux un mecanisme de degradation du biphenyle en phase

  15. Effect of various gases and chemical catalysts on phenol degradation pathways by pulsed electrical discharges

    Energy Technology Data Exchange (ETDEWEB)

    Shen Yongjun [Institute of Environmental Pollution Control Technologies, Zhejiang University, Hangzhou 310028 (China); Lei Lecheng [Institute of Environmental Pollution Control Technologies, Zhejiang University, Hangzhou 310028 (China)], E-mail: lclei@zju.edu.cn; Zhang Xingwang; Zhou Minghua; Zhang Yi [Institute of Environmental Pollution Control Technologies, Zhejiang University, Hangzhou 310028 (China)

    2008-02-11

    The processes of phenol degradation by pulsed electrical discharges were investigated under several kinds of discharge atmospheres (oxygen, argon, nitrogen and ozone) and chemical catalysts (ferrous ion and hydrogen peroxide). The temporal variations of the concentrations of phenol and the intermediate products were monitored by HPLC and GC-MS, respectively. It has been found that the effect of various gases bubbling on phenol degradation rate ranked in the following order: oxygen-containing ozone > oxygen > argon > nitrogen. The high gas bubbling flow rate was beneficial to the removal of phenol. It was found that the degradation proceeded differently when in the presence and absence of catalysts. The phenol removal rate was increased when ferrous ion was added. This considerable enhancement may be due to the Fenton's reaction. What's more, putting the chemical additives hydrogen peroxide into the reactor led to a dramatic increase in phenol degradation rate. The mechanism was due to the direct or indirect photolysis and pyrolysis destruction in plasma channel. Furthermore, the intermediate products were monitored by GC-MS under three degradation conditions. More THBs were generated under degradation conditions without gases bubbling or adding any catalyst, and more DHBs under the condition of adding ferrous ion, and more carboxylic acids under the condition of oxygen-containing ozone gas bubbling. Consequently, three distinct degradation pathways based on different conditions were proposed.

  16. Effect of various gases and chemical catalysts on phenol degradation pathways by pulsed electrical discharges.

    Science.gov (United States)

    Shen, Yongjun; Lei, Lecheng; Zhang, Xingwang; Zhou, Minghua; Zhang, Yi

    2008-02-11

    The processes of phenol degradation by pulsed electrical discharges were investigated under several kinds of discharge atmospheres (oxygen, argon, nitrogen and ozone) and chemical catalysts (ferrous ion and hydrogen peroxide). The temporal variations of the concentrations of phenol and the intermediate products were monitored by HPLC and GC-MS, respectively. It has been found that the effect of various gases bubbling on phenol degradation rate ranked in the following order: oxygen-containing ozone>oxygen>argon>nitrogen. The high gas bubbling flow rate was beneficial to the removal of phenol. It was found that the degradation proceeded differently when in the presence and absence of catalysts. The phenol removal rate was increased when ferrous ion was added. This considerable enhancement may be due to the Fenton's reaction. What's more, putting the chemical additives hydrogen peroxide into the reactor led to a dramatic increase in phenol degradation rate. The mechanism was due to the direct or indirect photolysis and pyrolysis destruction in plasma channel. Furthermore, the intermediate products were monitored by GC-MS under three degradation conditions. More THBs were generated under degradation conditions without gases bubbling or adding any catalyst, and more DHBs under the condition of adding ferrous ion, and more carboxylic acids under the condition of oxygen-containing ozone gas bubbling. Consequently, three distinct degradation pathways based on different conditions were proposed.

  17. Effect of various gases and chemical catalysts on phenol degradation pathways by pulsed electrical discharges

    International Nuclear Information System (INIS)

    Shen Yongjun; Lei Lecheng; Zhang Xingwang; Zhou Minghua; Zhang Yi

    2008-01-01

    The processes of phenol degradation by pulsed electrical discharges were investigated under several kinds of discharge atmospheres (oxygen, argon, nitrogen and ozone) and chemical catalysts (ferrous ion and hydrogen peroxide). The temporal variations of the concentrations of phenol and the intermediate products were monitored by HPLC and GC-MS, respectively. It has been found that the effect of various gases bubbling on phenol degradation rate ranked in the following order: oxygen-containing ozone > oxygen > argon > nitrogen. The high gas bubbling flow rate was beneficial to the removal of phenol. It was found that the degradation proceeded differently when in the presence and absence of catalysts. The phenol removal rate was increased when ferrous ion was added. This considerable enhancement may be due to the Fenton's reaction. What's more, putting the chemical additives hydrogen peroxide into the reactor led to a dramatic increase in phenol degradation rate. The mechanism was due to the direct or indirect photolysis and pyrolysis destruction in plasma channel. Furthermore, the intermediate products were monitored by GC-MS under three degradation conditions. More THBs were generated under degradation conditions without gases bubbling or adding any catalyst, and more DHBs under the condition of adding ferrous ion, and more carboxylic acids under the condition of oxygen-containing ozone gas bubbling. Consequently, three distinct degradation pathways based on different conditions were proposed

  18. Identification of an itaconic acid degrading pathway in itaconic acid producing Aspergillus terreus.

    Science.gov (United States)

    Chen, Mei; Huang, Xuenian; Zhong, Chengwei; Li, Jianjun; Lu, Xuefeng

    2016-09-01

    Itaconic acid, one of the most promising and flexible bio-based chemicals, is mainly produced by Aspergillus terreus. Previous studies to improve itaconic acid production in A. terreus through metabolic engineering were mainly focused on its biosynthesis pathway, while the itaconic acid-degrading pathway has largely been ignored. In this study, we used transcriptomic, proteomic, bioinformatic, and in vitro enzymatic analyses to identify three key enzymes, itaconyl-CoA transferase (IctA), itaconyl-CoA hydratase (IchA), and citramalyl-CoA lyase (CclA), that are involved in the catabolic pathway of itaconic acid in A. terreus. In the itaconic acid catabolic pathway in A. terreus, itaconic acid is first converted by IctA into itaconyl-CoA with succinyl-CoA as the CoA donor, and then itaconyl-CoA is hydrated into citramalyl-CoA by IchA. Finally, citramalyl-CoA is cleaved into acetyl-CoA and pyruvate by CclA. Moreover, IctA can also catalyze the reaction between citramalyl-CoA and succinate to generate succinyl-CoA and citramalate. These results, for the first time, identify the three key enzymes, IctA, IchA, and CclA, involved in the itaconic acid degrading pathway in itaconic acid producing A. terreus. The results will facilitate the improvement of itaconic acid production by metabolically engineering the catabolic pathway of itaconic acid in A. terreus.

  19. Modulation of apoptosis sensitivity through the interplay with autophagic and proteasomal degradation pathways

    Science.gov (United States)

    Delgado, M E; Dyck, L; Laussmann, M A; Rehm, M

    2014-01-01

    Autophagic and proteasomal degradation constitute the major cellular proteolysis pathways. Their physiological and pathophysiological adaptation and perturbation modulates the relative abundance of apoptosis-transducing proteins and thereby can positively or negatively adjust cell death susceptibility. In addition to balancing protein expression amounts, components of the autophagic and proteasomal degradation machineries directly interact with and co-regulate apoptosis signal transduction. The influence of autophagic and proteasomal activity on apoptosis susceptibility is now rapidly gaining more attention as a significant modulator of cell death signalling in the context of human health and disease. Here we present a concise and critical overview of the latest knowledge on the molecular interplay between apoptosis signalling, autophagy and proteasomal protein degradation. We highlight that these three pathways constitute an intricate signalling triangle that can govern and modulate cell fate decisions between death and survival. Owing to rapid research progress in recent years, it is now possible to provide detailed insight into the mechanisms of pathway crosstalk, common signalling nodes and the role of multi-functional proteins in co-regulating both protein degradation and cell death. PMID:24457955

  20. Metagenomic identification of bacterioplankton taxa and pathways involved in microcystin degradation in lake erie.

    Directory of Open Access Journals (Sweden)

    Xiaozhen Mou

    Full Text Available Cyanobacterial harmful blooms (CyanoHABs that produce microcystins are appearing in an increasing number of freshwater ecosystems worldwide, damaging quality of water for use by human and aquatic life. Heterotrophic bacteria assemblages are thought to be important in transforming and detoxifying microcystins in natural environments. However, little is known about their taxonomic composition or pathways involved in the process. To address this knowledge gap, we compared the metagenomes of Lake Erie free-living bacterioplankton assemblages in laboratory microcosms amended with microcystins relative to unamended controls. A diverse array of bacterial phyla were responsive to elevated supply of microcystins, including Acidobacteria, Actinobacteria, Bacteroidetes, Planctomycetes, Proteobacteria of the alpha, beta, gamma, delta and epsilon subdivisions and Verrucomicrobia. At more detailed taxonomic levels, Methylophilales (mainly in genus Methylotenera and Burkholderiales (mainly in genera Bordetella, Burkholderia, Cupriavidus, Polaromonas, Ralstonia, Polynucleobacter and Variovorax of Betaproteobacteria were suggested to be more important in microcystin degradation than Sphingomonadales of Alphaproteobacteria. The latter taxa were previously thought to be major microcystin degraders. Homologs to known microcystin-degrading genes (mlr were not overrepresented in microcystin-amended metagenomes, indicating that Lake Erie bacterioplankton might employ alternative genes and/or pathways in microcystin degradation. Genes for xenobiotic metabolism were overrepresented in microcystin-amended microcosms, suggesting they are important in bacterial degradation of microcystin, a phenomenon that has been identified previously only in eukaryotic systems.

  1. 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.

  2. 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

  3. Degradation of clofibric acid in UV/chlorine disinfection process: kinetics, reactive species contribution and pathways.

    Science.gov (United States)

    Tang, Yuqing; Shi, Xueting; Liu, Yongze; Feng, Li; Zhang, Liqiu

    2018-02-01

    As a potential endocrine disruptor, clofibric acid (CA) was investigated in this study for its degradation kinetics and pathways in UV/chlorine process. The results showed that CA in both UV photolysis and UV/chlorine processes could be degraded via pseudo-first-order kinetics, while it almost could not be degraded in the dark chlorination process. The observed rate constant ( k obs ) in UV photolysis was 0.0078 min -1, and increased to 0.0107 min -1 combining with 0.1 mM chlorine. The k obs increased to 0.0447 min -1 with further increasing the chlorine dosage from 0.1 to 1.0 mM, and reached a plateau at higher dosage (greater than 1.0 mM). The higher k obs was obtained at acid solution rather than basic solution. Moreover, the calculated contributions of radical species to k obs indicated that the HO• contributed significantly to CA degradation in acidic conditions, while the reactive chlorine species and UV direct photolysis dominated in neutral and basic solution. The degradation of CA was slightly inhibited in the presence of [Formula: see text] (1 ∼ 50 mM), barely affected by the presence of Cl - (1 ∼ 200 mM) and greatly suppressed by humic acid (0 ∼ 5 mg l -1 ). Thirteen main degradation intermediates and three degradation pathways of CA were identified during UV/chlorine process.

  4. Novel degradation pathway and kinetic analysis for buprofezin removal by newly isolated Bacillus sp.

    Science.gov (United States)

    Wang, Guangli; Xu, Dayong; Xiong, Minghua; Zhang, Hui; Li, Feng; Liu, Yuan

    2016-09-15

    Given the intensive and widespread application of the pesticide, buprofezin, its environmental residues potentially pose a problem; yet little is known about buprofezin's kinetic and metabolic behaviors. In this study, a novel gram-positive strain, designated BF-5, isolated from aerobic activated sludge, was found to be capable of metabolizing buprofezin as its sole energy, carbon, and nitrogen source. Based on its physiological and biochemical characteristics, other aspects of its phenotype, and a phylogenetic analysis, strain BF-5 was identified as Bacillus sp. This study investigated the effect of culture conditions on bacterial growth and substrate degradation, such as pH, temperature, initial concentration, different nitrogen source, and additional nitrogen sources as co-substrates. The degradation rate parameters, qmax, Ks, Ki and Sm were determined to be 0.6918 h(-1), 105.4 mg L(-1), 210.5 mg L(-1), and 148.95 mg L(-1) respectively. The capture of unpublished potential metabolites by gas chromatography-mass spectrometry (GC-MS) analysis has led to the proposal of a novel degradation pathway. Taken together, our results clarify buprofezin's biodegradation pathway(s) and highlight the promising potential of strain BF-5 in bioremediation of buprofezin-contaminated environments. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Secretion of intact proteins and peptide fragments by lysosomal pathways of protein degradation

    International Nuclear Information System (INIS)

    Isenman, L.D.; Dice, J.F.

    1989-01-01

    We report that degradation of proteins microinjected into human fibroblasts is accompanied by release into the culture medium of peptide fragments and intact proteins as well as single amino acids. For the nine proteins and polypeptides microinjected, acid-precipitable radioactivity, i.e. peptide fragments and/or intact proteins, ranged from 10 to 67% of the total released radioactivity. Peptide fragments and/or intact protein accounted for 60% of the radioactivity released into the medium by cells microinjected with ribonuclease A. Two major radiolabeled peptide fragments were found, and one was of an appropriate size to function as an antigen in antigen-presenting cells. The peptides released from microinjected ribonuclease A were derived from lysosomal pathways of proteolysis based on several lines of evidence. Previous studies have shown that microinjected ribonuclease A is degraded to single amino acids entirely within lysosomes. We show that release of free amino acids and peptide fragments and/or intact protein was equivalently stimulated by serum deprivation and equivalently inhibited by NH4Cl. We also show that lysosomal degradation of endocytosed [3H]ribonuclease A was accompanied by the release of two peptide fragments similar in size and charge to those from microinjected [ 3 H]ribonuclease A. These findings demonstrate that degradation within lysosomes occurs in a manner that spares specific peptides; they also suggest a previously unsuspected pathway by which cells can secrete cytosol-derived polypeptides

  6. Oxidative degradation of atenolol by heat-activated persulfate: Kinetics, degradation pathways and distribution of transformation intermediates.

    Science.gov (United States)

    Miao, Dong; Peng, Jianbiao; Zhou, Xiaohuan; Qian, Li; Wang, Mengjie; Zhai, Li; Gao, Shixiang

    2018-05-17

    Atenolol (ATL) has been widely detected in wastewater and aquatic environment. Although satisfactory removal of ATL from wastewater could be achieved, the mineralization ratio is usually low, which may result in the accumulation of its transformation products in the effluent and cause additional ecological risk to the environment. The aim of this study is to explore the effectiveness of heat activated persulfate (PS) in the removal of ATL from wastewater. Influencing factors including temperature, PS dosage, solution pH, existence of NO 3 - , Cl - , HCO 3 - and Suwannee river fulvic acid (SRFA) were examined. Complete removal of ATL was achieved within 40 min at pH 7.0 and 70 °C by using 0.5 mM PS. Inhibitive effects of HCO 3 - and FA had been observed on ATL oxidation, which was increased with the increase of their concentration. Sulfate radical (SO 4 - ) was determined as the main reactive species by quenching experiment. Eight intermediates produced in ATL degradation were identified, and four degradation pathways were proposed based on the analysis of mass spectrum and frontier electron densities. The distribution of major intermediates was influenced by reaction temperature. Hydroxylation intermediates and deamidation intermediate were the most prominent at 50 °C and 60 °C, respectively. All intermediates were completely degraded in 40 min except P134 at 70 °C. Effective removal of TOC (74.12%) was achieved with 0.5 mM PS, pH 7.0 and 70 °C after 240 min. The results proved that heat activation of PS is a promising method to remove organic pollutants in wastewater. Copyright © 2018 Elsevier Ltd. All rights reserved.

  7. 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

  8. 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.

  9. Identification of the degradation pathways of alkanolamines with TiO2 photocatalysis

    International Nuclear Information System (INIS)

    Lu, Chung-Shin; Chen, Chiing-Chang; Mai, Fu-Der; Li, Hua-Kuang

    2009-01-01

    The present study deals with the photocatalytic degradation of the alkanolamine, 2-dimethylamino-2-methyl-1-propanol (DMAMP), in the presence of TiO 2 particles and UV-A (λ = 365 nm) radiation. The obtained results show complete oxidation of DMAMP after 20 h, and a little over 90% of DMAMP was mineralization after 64-h of treatment. The effects of the solution pH, catalyst loading, and anions on the photocatalytic degradation of DMAMP were investigated, as well as the reaction intermediates that were formed during treatment. To the best of our knowledge, this is the first time that reports the degradation pathways of DMAMP. A number of intermediates were identified by GC/MS techniques during the treatment of DMAMP, following three tentative degradation routes. The first one is based on the oxidation of the primary alcohol group leading to the formation of corresponding aldehyde and carboxylic acid. The second route is based on the rupture of the N-C bond to form 2-methylpropanal and acetone. The last degradation route is based on the cyclization of the β-amino alcohol group to form the oxazolidine derivatives.

  10. Interleukin-1 Acts via the JNK-2 Signaling Pathway to Induce Aggrecan Degradation by Human Chondrocytes.

    Science.gov (United States)

    Ismail, Heba M; Yamamoto, Kazuhiro; Vincent, Tonia L; Nagase, Hideaki; Troeberg, Linda; Saklatvala, Jeremy

    2015-07-01

    Aggrecan enables articular cartilage to bear load and resist compression. Aggrecan loss occurs early in osteoarthritis and rheumatoid arthritis and can be induced by inflammatory cytokines such as interleukin-1 (IL-1). IL-1 induces cleavage of specific aggrecans characteristic of the ADAMTS proteinases. The aim of this study was to identify the intracellular signaling pathways by which IL-1 causes aggrecan degradation by human chondrocytes and to investigate how aggrecanase activity is controlled by chondrocytes. We developed a cell-based assay combining small interfering RNA (siRNA)-induced knockdown with aggrecan degradation assays. Human articular chondrocytes were overlaid with bovine aggrecan after transfection with siRNAs against molecules of the IL-1 signaling pathway. After IL-1 stimulation, released aggrecan fragments were detected with AGEG and ARGS neoepitope antibodies. Aggrecanase activity and tissue inhibitor of metalloproteinases 3 levels were measured by enzyme-linked immunosorbent assay. Low-density lipoprotein receptor-related protein 1 (LRP-1) shedding was analyzed by Western blotting. ADAMTS-5 is a major aggrecanase in human chondrocytes, regulating aggrecan degradation in response to IL-1. The tumor necrosis factor receptor-associated 6 (TRAF-6)/transforming growth factor β-activated kinase 1 (TAK-1)/MKK-4 signaling axis is essential for IL-1-induced aggrecan degradation, while NF-κB is not. Of the 3 MAPKs (ERK, p38, and JNK), only JNK-2 showed a significant role in aggrecan degradation. Chondrocytes constitutively secreted aggrecanase, which was continuously endocytosed by LRP-1, keeping the extracellular level of aggrecanase low. IL-1 induced aggrecanase activity in the medium in a JNK-2-dependent manner, possibly by reducing aggrecanase endocytosis, because IL-1 caused JNK-2-dependent shedding of LRP-1. The signaling axis TRAF-6/TAK-1/MKK-4/JNK-2 mediates IL-1-induced aggrecanolysis. The level of aggrecanase is controlled by its

  11. HECTD3 Mediates an HSP90-Dependent Degradation Pathway for Protein Kinase Clients

    Directory of Open Access Journals (Sweden)

    Zhaobo Li

    2017-06-01

    Full Text Available Inhibition of the ATPase cycle of the HSP90 chaperone promotes ubiquitylation and proteasomal degradation of its client proteins, which include many oncogenic protein kinases. This provides the rationale for HSP90 inhibitors as cancer therapeutics. However, the mechanism by which HSP90 ATPase inhibition triggers ubiquitylation is not understood, and the E3 ubiquitin ligases involved are largely unknown. Using a siRNA screen, we have identified components of two independent degradation pathways for the HSP90 client kinase CRAF. The first requires CUL5, Elongin B, and Elongin C, while the second requires the E3 ligase HECTD3, which is also involved in the degradation of MASTL and LKB1. HECTD3 associates with HSP90 and CRAF in cells via its N-terminal DOC domain, which is mutationally disrupted in tumor cells with activated MAP kinase signaling. Our data implicate HECTD3 as a tumor suppressor modulating the activity of this important oncogenic signaling pathway.

  12. 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.

  13. Decomposition of clofibric acid in aqueous media by advance oxidation techniques: kinetics study and degradation pathway

    International Nuclear Information System (INIS)

    Syed, M.; Khan, A.M.; Khan, R.A.

    2016-01-01

    This study investigates the decomposition of clofibric acid (CLF) by different advanced oxidation processes (AOPs), such as UV (254 nm), VUV (185 nm), UV / TiO/sub 2/ and VUV / TiO/sub 2/. The removal efficiencies of applied AOPs were compared in the presence and absence of dissolved oxygen. The removal efficiency of the studied AOPs towards degradation of CLF were found in the order of VUV / TiO/sub 2/ + O/sub 2/ > VUV/TiO/sub 2/ + N/sub 2/ > VUV alone > UV / TiO/sub 2/ + O/sub 2/ > UV / TiO/sub 2/ +N/sub 2/ > UV alone. The decomposition kinetics of CLF was found to follow pseudo-first order rate law. VUV / TiO2 process was found to be most cheap and effective one for decomposition of CLF as compared to other applied AOPs in terms of electrical energy per order. Degradation products resulting from the degradation processes were also investigated using UPLC-MS /MS, accordingly degradation pathway was proposed. (author)

  14. Role of rhizosphere microorganisms in phytoremediation of biphenyl in a contaminated groundwater plume

    International Nuclear Information System (INIS)

    Sun, B.; Ramsay, J.

    2007-01-01

    This presentation discussed a pump and treat technology used in combination with a phytoremediation technology to remediate a biphenyl contaminated groundwater plume. Biphenyl is used in industrial applications as fungicide and heat transfer agent. It is highly toxic, has poor water solubility and sorbs strongly to soils. Costs for the project were estimated at $860,000 over a period of 20 years, while it was estimated that the addition of phytoremediation would cost only $125,000 over a period of 20 years. The phytoremediation containment area was added to the site which was comprised of a pump and treat system and landfill lagoons. In situ biodegradation of biphenyl was evaluated using microorganisms in poplar and willow rhizospheres. Basal salts were used as a culture medium. Methods to enhance biphenyl degradation were also investigated. Aerobic growth on biphenyl at temperatures of 8 degrees C were measured, and microbial populations were identified. The consortium with the highest biphenyl degradation was then analyzed. Major members were identified as Burkholderia xenovorans LB400 and a strain of Burkholderia xenovorans. Nitrate reduction, sulphate reduction, and methanogens were measured. Enrichment of anaerobic biphenyl degraders. Anaerobic biphenyl degradation was measured after 90 days. Details of anaerobic mineralization experiments were also provided. It was concluded that anaerobic biphenyl degradation was enhanced by TEA and fertilizer addition, as well as by poplar root exudate. tabs., figs

  15. Finding Solvable Units of Variables in Nonlinear ODEs of ECM Degradation Pathway Network

    Directory of Open Access Journals (Sweden)

    Shuji Kawasaki

    2017-01-01

    Full Text Available We consider ordinary differential equation (ODE model for a pathway network that arises in extracellular matrix (ECM degradation. For solving the ODEs, we propose applying the mass conservation law (MCL, together with a stoichiometry called doubling rule, to them. Then it leads to extracting new units of variables in the ODEs that can be solved explicitly, at least in principle. The simulation results for the ODE solutions show that the numerical solutions are indeed in good accord with theoretical solutions and satisfy the MALs.

  16. Finding Solvable Units of Variables in Nonlinear ODEs of ECM Degradation Pathway Network.

    Science.gov (United States)

    Kawasaki, Shuji; Minerva, Dhisa; Itano, Keiko; Suzuki, Takashi

    2017-01-01

    We consider ordinary differential equation (ODE) model for a pathway network that arises in extracellular matrix (ECM) degradation. For solving the ODEs, we propose applying the mass conservation law (MCL), together with a stoichiometry called doubling rule , to them. Then it leads to extracting new units of variables in the ODEs that can be solved explicitly, at least in principle. The simulation results for the ODE solutions show that the numerical solutions are indeed in good accord with theoretical solutions and satisfy the MALs.

  17. 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.

  18. ERManI (Endoplasmic Reticulum Class I α-Mannosidase) Is Required for HIV-1 Envelope Glycoprotein Degradation via Endoplasmic Reticulum-associated Protein Degradation Pathway.

    Science.gov (United States)

    Zhou, Tao; Frabutt, Dylan A; Moremen, Kelley W; Zheng, Yong-Hui

    2015-09-04

    Previously, we reported that the mitochondrial translocator protein (TSPO) induces HIV-1 envelope (Env) degradation via the endoplasmic reticulum (ER)-associated protein degradation (ERAD) pathway, but the mechanism was not clear. Here we investigated how the four ER-associated glycoside hydrolase family 47 (GH47) α-mannosidases, ERManI, and ER-degradation enhancing α-mannosidase-like (EDEM) proteins 1, 2, and 3, are involved in the Env degradation process. Ectopic expression of these four α-mannosidases uncovers that only ERManI inhibits HIV-1 Env expression in a dose-dependent manner. In addition, genetic knock-out of the ERManI gene MAN1B1 using CRISPR/Cas9 technology disrupts the TSPO-mediated Env degradation. Biochemical studies show that HIV-1 Env interacts with ERManI, and between the ERManI cytoplasmic, transmembrane, lumenal stem, and lumenal catalytic domains, the catalytic domain plays a critical role in the Env-ERManI interaction. In addition, functional studies show that inactivation of the catalytic sites by site-directed mutagenesis disrupts the ERManI activity. These studies identify ERManI as a critical GH47 α-mannosidase in the ER-associated protein degradation pathway that initiates the Env degradation and suggests that its catalytic domain and enzymatic activity play an important role in this process. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  19. REDOX AND REDUCTION POTENTIALS AS PARAMETERS TO PREDICT THE DEGRADATION PATHWAY OF CHLORINATED BENZENES IN ANAEROBIC ENVIRONMENTS

    NARCIS (Netherlands)

    DOLFING, J; HARRISON, BK

    1993-01-01

    The anaerobic degradation pathway of hexachlorobenzene starts with a series of reductive dehalogenation steps. In the present paper it was evaluated whether the dehalogenation pathway observed in microbial ecosystems could be predicted by the redox potential and/or the reduction potential (the

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Aqueous photodegradation of 4-tert-butylphenol: By-products, degradation pathway and theoretical calculation assessment

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yanlin [State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Shi, Jin; Chen, Hongche [Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433 (China); Zhao, Jianfu [State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Dong, Wenbo, E-mail: wbdong@fudan.edu.cn [Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433 (China)

    2016-10-01

    4-tert-butylphenol (4-t-BP), an endocrine disrupting chemical, is widely distributed in natural bodies of water but is difficult to biodegrade. In this study, we focused on the transformation of 4-t-BP in photo-initiated degradation processes. The steady-state photolysis and laser flash photolysis (LFP) experiments were conducted in order to elucidate its degradation mechanism. Identification of products was performed using the GC–MS, LC-MS and theoretical calculation techniques. The oxidation pathway of 4-t-BP by hydroxyl radical (HO·) was also studied and H{sub 2}O{sub 2} was added to produce HO·. 4-tert-butylcatechol and 4-tert-butylphenol dimer were produced in 4-t-BP direct photolysis. 4-tert-butylcatechol and hydroquinone were produced by the oxidation of HO·. But the formation mechanism of 4-tert-butylcatechol in the two processes was different. The benzene ring was fractured in 4-t-BP oxidation process and 29% of TOC was degraded after 16 h irradiation. - Highlights: • Photodegradation of 4-t-BP, an endocrine disrupting chemical, has been investigated. • 3 stable byproducts were identified from photolysis and oxidation processes. • 5 transient by-products were concluded from LFP experiments. • The theoretical calculation was performed to confirm the byproducts. • 4-t-BP was degraded with increasing efficiency: 254 nm < H{sub 2}O{sub 2}/313 nm < H{sub 2}O{sub 2}/254 nm.

  5. 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

  6. Cycle Inhibiting Factors (Cifs: Cyclomodulins That Usurp the Ubiquitin-Dependent Degradation Pathway of Host Cells

    Directory of Open Access Journals (Sweden)

    Eric Oswald

    2011-03-01

    Full Text Available Cycle inhibiting factors (Cifs are type III secreted effectors produced by diverse pathogenic bacteria. Cifs are “cyclomodulins” that inhibit the eukaryotic host cell cycle and also hijack other key cellular processes such as those controlling the actin network and apoptosis. This review summarizes current knowledge on Cif since its first characterization in enteropathogenic Escherichia coli, the identification of several xenologues in distant pathogenic bacteria, to its structure elucidation and the recent deciphering of its mode of action. Cif impairs the host ubiquitin proteasome system through deamidation of ubiquitin or the ubiquitin-like protein NEDD8 that regulates Cullin-Ring-ubiquitin Ligase (CRL complexes. The hijacking of the ubiquitin-dependent degradation pathway of host cells results in the modulation of various cellular functions such as epithelium renewal, apoptosis and immune response. Cif is therefore a powerful weapon in the continuous arm race that characterizes host-bacteria interactions.

  7. Photocatalytic degradation of metoprolol tartrate in suspensions of two TiO2-based photocatalysts with different surface area. Identification of intermediates and proposal of degradation pathways

    International Nuclear Information System (INIS)

    Abramović, Biljana; Kler, Sanja; Šojić, Daniela; Laušević, Mila; Radović, Tanja; Vione, Davide

    2011-01-01

    Highlights: ► Kinetics and efficiency of photocatalytic degradation of the β 1 -blocker metoprolol tartrate (MET). ► Two TiO 2 specimens employed. ► Faster degradation of MET, but slower mineralization, obtained with the TiO 2 specimen having lower surface area. ► Photocatalytic transformation pathways of MET including mineralization. - Abstract: This study investigates the efficiency of the photocatalytic degradation of metoprolol tartrate (MET), a widely used β 1 -blocker, in TiO 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 2 Wackherr induced a significantly faster MET degradation compared to TiO 2 Degussa P25 when relatively high substrate concentrations were used. By examining the effect of ethanol as a scavenger of hydroxyl radicals (·OH), it was shown that the reaction with ·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 2 and H 2 O, while the nitrogen was predominantly present as NH 4 + . 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 2 specimen.

  8. 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.

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

    Science.gov (United States)

    Madsen, Daniel H.; Leonard, Daniel; Masedunskas, Andrius; Moyer, Amanda; Jürgensen, Henrik Jessen; Peters, Diane E.; Amornphimoltham, Panomwat; Selvaraj, Arul; Yamada, Susan S.; Brenner, David A.; Burgdorf, Sven; Engelholm, Lars H.; Behrendt, Niels; Holmbeck, Kenn; Weigert, Roberto

    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 of the collagen receptors mannose receptor (Mrc1) and urokinase plasminogen activator receptor–associated protein (Endo180 and Mrc2) impaired this intracellular collagen degradation pathway. This study demonstrates the importance of receptor-mediated cellular uptake to collagen turnover in vivo and identifies a key role of M2-like macrophages in this process. PMID:24019537

  10. Characterization of the complete uric acid degradation pathway in the fungal pathogen Cryptococcus neoformans.

    Directory of Open Access Journals (Sweden)

    I Russel Lee

    Full Text Available Degradation of purines to uric acid is generally conserved among organisms, however, the end product of uric acid degradation varies from species to species depending on the presence of active catabolic enzymes. In humans, most higher primates and birds, the urate oxidase gene is non-functional and hence uric acid is not further broken down. Uric acid in human blood plasma serves as an antioxidant and an immune enhancer; conversely, excessive amounts cause the common affliction gout. In contrast, uric acid is completely degraded to ammonia in most fungi. Currently, relatively little is known about uric acid catabolism in the fungal pathogen Cryptococcus neoformans even though this yeast is commonly isolated from uric acid-rich pigeon guano. In addition, uric acid utilization enhances the production of the cryptococcal virulence factors capsule and urease, and may potentially modulate the host immune response during infection. Based on these important observations, we employed both Agrobacterium-mediated insertional mutagenesis and bioinformatics to predict all the uric acid catabolic enzyme-encoding genes in the H99 genome. The candidate C. neoformans uric acid catabolic genes identified were named: URO1 (urate oxidase, URO2 (HIU hydrolase, URO3 (OHCU decarboxylase, DAL1 (allantoinase, DAL2,3,3 (allantoicase-ureidoglycolate hydrolase fusion protein, and URE1 (urease. All six ORFs were then deleted via homologous recombination; assaying of the deletion mutants' ability to assimilate uric acid and its pathway intermediates as the sole nitrogen source validated their enzymatic functions. While Uro1, Uro2, Uro3, Dal1 and Dal2,3,3 were demonstrated to be dispensable for virulence, the significance of using a modified animal model system of cryptococcosis for improved mimicking of human pathogenicity is discussed.

  11. 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

  12. 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.

  13. Degradation of PHLPP2 by KCTD17, via a Glucagon-Dependent Pathway, Promotes Hepatic Steatosis.

    Science.gov (United States)

    Kim, KyeongJin; Ryu, Dongryeol; Dongiovanni, Paola; Ozcan, Lale; Nayak, Shruti; Ueberheide, Beatrix; Valenti, Luca; Auwerx, Johan; Pajvani, Utpal B

    2017-12-01

    and in liver biopsies patients with NAFLD, compared with liver tissues from healthy control mice or patients without steatosis. Knockdown of KCTD17 with small hairpin RNA in primary hepatocytes increased PHLPP2 protein but not Phlpp2 mRNA, indicating that KCTD17 mediates PHLPP2 degradation. KCTD17 knockdown in obese mice prevented PHLPP2 degradation and decreased expression of lipogenic genes. In mouse models of obesity, we found that PHLPP2 degradation induced lipogenesis without affecting gluconeogenesis. KCTD17, which is up-regulated in liver tissues of obese mice and patients with NAFLD, binds to phosphorylated PHLPP2 to target it for ubiquitin-mediated degradation; this increases expression of genes that regulate lipogenesis to promote hepatic steatosis. Inhibitors of this pathway might be developed for treatment of patients with NAFLD. Copyright © 2017 AGA Institute. Published by Elsevier Inc. All rights reserved.

  14. A non-canonical RNA degradation pathway suppresses RNAi-dependent epimutations in the human fungal pathogen Mucor circinelloides.

    Science.gov (United States)

    Calo, Silvia; Nicolás, Francisco E; Lee, Soo Chan; Vila, Ana; Cervantes, Maria; Torres-Martinez, Santiago; Ruiz-Vazquez, Rosa M; Cardenas, Maria E; Heitman, Joseph

    2017-03-01

    Mucorales are a group of basal fungi that includes the casual agents of the human emerging disease mucormycosis. Recent studies revealed that these pathogens activate an RNAi-based pathway to rapidly generate drug-resistant epimutant strains when exposed to stressful compounds such as the antifungal drug FK506. To elucidate the molecular mechanism of this epimutation pathway, we performed a genetic analysis in Mucor circinelloides that revealed an inhibitory role for the non-canonical RdRP-dependent Dicer-independent silencing pathway, which is an RNAi-based mechanism involved in mRNA degradation that was recently identified. Thus, mutations that specifically block the mRNA degradation pathway, such as those in the genes r3b2 and rdrp3, enhance the production of drug resistant epimutants, similar to the phenotype previously described for mutation of the gene rdrp1. Our genetic analysis also revealed two new specific components of the epimutation pathway related to the quelling induced protein (qip) and a Sad-3-like helicase (rnhA), as mutations in these genes prevented formation of drug-resistant epimutants. Remarkably, drug-resistant epimutant production was notably increased in M. circinelloides f. circinelloides isolates from humans or other animal hosts. The host-pathogen interaction could be a stressful environment in which the phenotypic plasticity provided by the epimutant pathway might provide an advantage for these strains. These results evoke a model whereby balanced regulation of two different RNAi pathways is determined by the activation of the RNAi-dependent epimutant pathway under stress conditions, or its repression when the regular maintenance of the mRNA degradation pathway operates under non-stress conditions.

  15. A non-canonical RNA degradation pathway suppresses RNAi-dependent epimutations in the human fungal pathogen Mucor circinelloides.

    Directory of Open Access Journals (Sweden)

    Silvia Calo

    2017-03-01

    Full Text Available Mucorales are a group of basal fungi that includes the casual agents of the human emerging disease mucormycosis. Recent studies revealed that these pathogens activate an RNAi-based pathway to rapidly generate drug-resistant epimutant strains when exposed to stressful compounds such as the antifungal drug FK506. To elucidate the molecular mechanism of this epimutation pathway, we performed a genetic analysis in Mucor circinelloides that revealed an inhibitory role for the non-canonical RdRP-dependent Dicer-independent silencing pathway, which is an RNAi-based mechanism involved in mRNA degradation that was recently identified. Thus, mutations that specifically block the mRNA degradation pathway, such as those in the genes r3b2 and rdrp3, enhance the production of drug resistant epimutants, similar to the phenotype previously described for mutation of the gene rdrp1. Our genetic analysis also revealed two new specific components of the epimutation pathway related to the quelling induced protein (qip and a Sad-3-like helicase (rnhA, as mutations in these genes prevented formation of drug-resistant epimutants. Remarkably, drug-resistant epimutant production was notably increased in M. circinelloides f. circinelloides isolates from humans or other animal hosts. The host-pathogen interaction could be a stressful environment in which the phenotypic plasticity provided by the epimutant pathway might provide an advantage for these strains. These results evoke a model whereby balanced regulation of two different RNAi pathways is determined by the activation of the RNAi-dependent epimutant pathway under stress conditions, or its repression when the regular maintenance of the mRNA degradation pathway operates under non-stress conditions.

  16. 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.

  17. 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.

  18. 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.

  19. The mitochondrial translocator protein, TSPO, inhibits HIV-1 envelope glycoprotein biosynthesis via the endoplasmic reticulum-associated protein degradation pathway.

    Science.gov (United States)

    Zhou, Tao; Dang, Ying; Zheng, Yong-Hui

    2014-03-01

    The HIV-1 Env glycoprotein is folded in the endoplasmic reticulum (ER), which is necessary for viral entry and replication. Currently, it is still unclear how this process is regulated. The glycoprotein folding in the ER is controlled by the ER-associated protein degradation (ERAD) pathway, which specifically targets misfolded proteins for degradation. Previously, we reported that HIV-1 replication is restricted in the human CD4(+) T cell line CEM.NKR (NKR). To understand this mechanism, we first analyzed cellular protein expression in NKR cells and discovered that levels of the mitochondrial translocator protein TSPO were upregulated by ∼64-fold. Notably, when NKR cells were treated with TSPO antagonist PK-11195, Ro5-4864, or diazepam, HIV restriction was completely disrupted, and TSPO knockdown by short hairpin RNAs (shRNAs) achieved a similar effect. We next analyzed viral protein expression, and, interestingly, we discovered that Env expression was specifically inhibited. Both TSPO knockdown and treatment with TSPO antagonist could restore Env expression in NKR cells. We further discovered that Env proteins were rapidly degraded and that kifunensine, an ERAD pathway inhibitor, could restore Env expression and viral replication, indicating that Env proteins were misfolded and degraded through the ERAD pathway in NKR cells. We also knocked out the TSPO gene in 293T cells using CRISPR/Cas9 (clustered, regularly interspaced, short palindromic repeat [CRISPR]/CRISPR-associated-9) technology and found that TSPO could similarly inhibit Env expression in these cells. Taken together, these results demonstrate that TSPO inhibits Env protein expression through the ERAD pathway and suggest that mitochondria play an important role in regulating the Env folding process. The HIV-1 Env glycoprotein is absolutely required for viral infection, and an understanding of its expression pathway in infected cells will identify new targets for antiretroviral therapies. Env proteins

  20. Degraded iota-carrageenan can induce apoptosis in human osteosarcoma cells via the Wnt/β-catenin signaling pathway.

    Science.gov (United States)

    Jin, Zhe; Han, Ya-Xin; Han, Xiao-Rui

    2013-01-01

    Osteosarcoma (OS) is a high-grade malignant bone tumor. Therefore, using both in vitro and in vivo assays, the effects of degraded iota-Carrageenan (ι-CGN) on a human osteosarcoma cell line, HOS, were examined. Degraded ι-CGN was observed to induce apoptosis and G(1) phase arrest in HOS cells. Moreover, degraded ι-CGN suppressed tumor growth in established xenograft tumor models. Accordingly, the survival rate of these mice was significantly higher than that of mice bearing tumors treated with native ι-CGN or PBS. In addition, the formation of intratumoral microvessels was inhibited following treatment with degraded ι-CGN. In Western blot assays, degraded ι-CGN was found to inhibit the Wnt/β-catenin signaling pathway. Overall, these studies demonstrate the antitumor activity of degraded ι-CGN toward the OS cell line, HOS. Moreover, valuable insight into the mechanisms mediated by degraded ι-CGN was obtained, potentially leading to the identification of novel treatments for OS. However, additional studies are needed to confirm these results in other cell types, particularly in human umbilical vein endothelial cells.

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

    International Nuclear Information System (INIS)

    Kang, Liang; Hu, Jia; Weng, Yuxiong; Jia, Jie; Zhang, Yukun

    2017-01-01

    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.

  2. 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.

  3. Chemotaxis and degradation of organophosphate compound by a novel moderately thermo-halo tolerant Pseudomonas sp. strain BUR11: evidence for possible existence of two pathways for degradation

    Directory of Open Access Journals (Sweden)

    Santanu Pailan

    2015-11-01

    Full Text Available An organophosphate (OP degrading chemotactic bacterial strain BUR11 isolated from an agricultural field was identified as a member of Pseudomonas genus on the basis of its 16S rRNA gene sequence. The strain could utilize parathion, chlorpyrifos and their major hydrolytic intermediates as sole source of carbon for its growth and exhibited positive chemotactic response towards most of them. Optimum concentration of parathion for its growth was recorded to be 200 ppm and 62% of which was degraded within 96 h at 37 °C. Growth studies indicated the strain to be moderately thermo-halo tolerant in nature. Investigation based on identification of intermediates of parathion degradation by thin layer chromatography (TLC, high performance liquid chromatography (HPLC, gas chromatography (GC and liquid chromatography mass spectrometry (LC-MS/MS provided evidence for possible existence of two pathways. The first pathway proceeds via 4-nitrophenol (4-NP while the second proceeds through formation of 4-aminoparathion (4-APar, 4-aminophenol (4-AP and parabenzoquinone (PBQ. This is the first report of chemotaxis towards organophosphate compound by a thermo-halo tolerant bacterium.

  4. 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.

  5. 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.

  6. 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 ...

  7. The N-end rule pathway catalyzes a major fraction of the protein degradation in skeletal muscle

    Science.gov (United States)

    Solomon, V.; Lecker, S. H.; Goldberg, A. L.

    1998-01-01

    In skeletal muscle, overall protein degradation involves the ubiquitin-proteasome system. One property of a protein that leads to rapid ubiquitin-dependent degradation is the presence of a basic, acidic, or bulky hydrophobic residue at its N terminus. However, in normal cells, substrates for this N-end rule pathway, which involves ubiquitin carrier protein (E2) E214k and ubiquitin-protein ligase (E3) E3alpha, have remained unclear. Surprisingly, in soluble extracts of rabbit muscle, we found that competitive inhibitors of E3alpha markedly inhibited the 125I-ubiquitin conjugation and ATP-dependent degradation of endogenous proteins. These inhibitors appear to selectively inhibit E3alpha, since they blocked degradation of 125I-lysozyme, a model N-end rule substrate, but did not affect the degradation of proteins whose ubiquitination involved other E3s. The addition of several E2s or E3alpha to the muscle extracts stimulated overall proteolysis and ubiquitination, but only the stimulation by E3alpha or E214k was sensitive to these inhibitors. A similar general inhibition of ubiquitin conjugation to endogenous proteins was observed with a dominant negative inhibitor of E214k. Certain substrates of the N-end rule pathway are degraded after their tRNA-dependent arginylation. We found that adding RNase A to muscle extracts reduced the ATP-dependent proteolysis of endogenous proteins, and supplying tRNA partially restored this process. Finally, although in muscle extracts the N-end rule pathway catalyzes most ubiquitin conjugation, it makes only a minor contribution to overall protein ubiquitination in HeLa cell extracts.

  8. 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

  9. 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

  10. 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

  11. Enrichment of Bacteria From Eastern Mediterranean Sea Involved in Lignin Degradation via the Phenylacetyl-CoA Pathway

    Directory of Open Access Journals (Sweden)

    Hannah L. Woo

    2018-05-01

    Full Text Available The degradation of allochthonous terrestrial organic matter, such as recalcitrant lignin and hemicellulose from plants, occurs in the ocean. We hypothesize that bacteria instead of white-rot fungi, the model organisms of aerobic lignin degradation within terrestrial environments, are responsible for lignin degradation in the ocean due to the ocean’s oligotrophy and hypersalinity. Warm oxic seawater from the Eastern Mediterranean Sea was enriched on lignin in laboratory microcosms. Lignin mineralization rates by the lignin-adapted consortia improved after two sequential incubations. Shotgun metagenomic sequencing detected a higher abundance of aromatic compound degradation genes in response to lignin, particularly phenylacetyl-CoA, which may be an effective strategy for marine microbes in fluctuating oxygen concentrations. 16S rRNA gene amplicon sequencing detected a higher abundance of Gammaproteobacteria and Alphaproteobacteria bacteria such as taxonomic families Idiomarinaceae, Alcanivoraceae, and Alteromonadaceae in response to lignin. Meanwhile, fungal Ascomycetes and Basidiomycetes remained at very low abundance. Our findings demonstrate the significant potential of bacteria and microbes utilizing the phenylacetyl-CoA pathway to contribute to lignin degradation in the Eastern Mediterranean where environmental conditions are unfavorable for fungi. Exploring the diversity of bacterial lignin degraders may provide important enzymes for lignin conversion in industry. Enzymes may be key in breaking down high molecular weight lignin and enabling industry to use it as a low-cost and sustainable feedstock for biofuels or other higher-value products.

  12. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Masaya; Kawanabe, Mitsuyoshi; Hayashi, Yoko; Endo, Toshiya [Department of Chemistry, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602 (Japan); Nishikawa, Shuh-ichi, E-mail: shuh@biochem.chem.nagoya-u.ac.jp [Department of Chemistry, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602 (Japan)

    2010-03-12

    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.

  14. Biphenyl-metabolizing bacteria in the rhizosphere of horseradish and bulk soil contaminated by polychlorinated biphenyls as revealed by stable isotope probing.

    Science.gov (United States)

    Uhlik, Ondrej; Jecna, Katerina; Mackova, Martina; Vlcek, Cestmir; Hroudova, Miluse; Demnerova, Katerina; Paces, Vaclav; Macek, Tomas

    2009-10-01

    DNA-based stable isotope probing in combination with terminal restriction fragment length polymorphism was used in order to identify members of the microbial community that metabolize biphenyl in the rhizosphere of horseradish (Armoracia rusticana) cultivated in soil contaminated with polychlorinated biphenyls (PCBs) compared to members of the microbial community in initial, uncultivated bulk soil. On the basis of early and recurrent detection of their 16S rRNA genes in clone libraries constructed from [(13)C]DNA, Hydrogenophaga spp. appeared to dominate biphenyl catabolism in the horseradish rhizosphere soil, whereas Paenibacillus spp. were the predominant biphenyl-utilizing bacteria in the initial bulk soil. Other bacteria found to derive carbon from biphenyl in this nutrient-amended microcosm-based study belonged mostly to the class Betaproteobacteria and were identified as Achromobacter spp., Variovorax spp., Methylovorus spp., or Methylophilus spp. Some bacteria that were unclassified at the genus level were also detected, and these bacteria may be members of undescribed genera. The deduced amino acid sequences of the biphenyl dioxygenase alpha subunits (BphA) from bacteria that incorporated [(13)C]into DNA in 3-day incubations of the soils with [(13)C]biphenyl are almost identical to that of Pseudomonas alcaligenes B-357. This suggests that the spectrum of the PCB congeners that can be degraded by these enzymes may be similar to that of strain B-357. These results demonstrate that altering the soil environment can result in the participation of different bacteria in the metabolism of biphenyl.

  15. Optical detection of polychlorinated biphenyls

    Science.gov (United States)

    Kuncova, Gabriela; Berkova, Daniela; Burkhard, Jiri; Demnerova, Katerina; Pazlarova, Jarmila; Triska, Jan; Vrchotova, Nadezda

    1999-12-01

    In this paper we describe the detection of polychlorinated biphenyls (PCBs) which is based on the measurement of changes of optical absorption at 400 nm of the medium in an aerobic bioreactor with immobilized cells Pseudomonas species 2. The rate of production, composition and the concentration of yellow intermediates are influenced by concentration and composition of PCB mixtures, concentration of cells and by the methods of immobilization. The method was applied in the detection of commercial mixture D103. It was found that the advantageous carriers were inorganic or organic-inorganic matrices, which sorbed PCBs and a cell outgrowth from their surface was low. In water contaminated with transformer oil and chlorinated hydrocarbons the detection limit is 10-2 gD103/kg. In transformer oil the upper limit for degradation of D103 by sodium dehalogenation (1.5 gD103 /kgoil) was determined also in the presence of the same concentration of trichloroethylene. The employment to of a liquid core waveguide spectrophotometer instead of a diode array spectrophotometer increased the sensitivity of the measurement of yellow intermediates by a factor of 100. An extrinsic fiber-optic sensor was used for in-situ measurement during biodegradation of PCBs in bioreactors.

  16. 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.

  17. 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.

  18. 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.)

  19. 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...

  20. 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.

  1. 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.

  2. Bioactive lysophospholipids generated by hepatic lipase degradation of lipoproteins lead to complement activation via the classical pathway.

    Science.gov (United States)

    Ma, Wanchao; Paik, David C; Barile, Gaetano R

    2014-09-09

    We determined bioactivity of lysophospholipids generated by degradation of the low-density (LDL), very low-density (VLDL), and high-density (HDL) lipoproteins with hepatic lipase (HL), cholesterol esterase (CE), and lipoprotein-associated phospholipase A2 (Lp-PLA2). The LDL, VLDL, and HDL were treated with HL, CE, and Lp-PLA2 after immobilization on plates, and complement activation studies were performed with diluted human serum. Complement component 3 (C3) fixation, a marker for complement activation, was determined with a monoclonal anti-human C3d antibody. Enzymatic properties of HL and CE were assayed with triglyceride and phosphatidylcholine substrates for triglyceride hydrolase and phospholipase A activities. The ARPE-19 cells were used for viability studies. The HL degradation of human lipoproteins LDL, VLDL, or HDL results in the formation of modified lipoproteins that can activate the complement pathway. Complement activation is dose- and time-dependent upon HL and occurs via the classical pathway. Enzymatic studies suggest that the phospholipase A1 activity of HL generates complement-activating lysophospholipids. C-reactive protein (CRP), known to simultaneously interact with complement C1 and complement factor H (CFH), further enhances HL-induced complement activation. The lysophospholipids, 1-Palmitoyl-sn-glycero-3-phosphocholine and 1-Oleoyl-sn-glycero-3-phosphocholine, can be directly cytotoxic to ARPE-19 cells. The HL degradation of lipoproteins, known to accumulate in the outer retina and in drusen, can lead to the formation of bioactive lysophospholipids that can trigger complement activation and induce RPE cellular dysfunction. Given the known risk associations for age-related macular degeneration (AMD) with HL, CRP, and CFH, this study elucidates a possible damage pathway for age-related macular degeneration (AMD) in genetically predisposed individuals, that HL activity may lead to accumulation of lysophospholipids to initiate complement

  3. 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

  4. 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.

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

    Science.gov (United States)

    Koopman, Frank; Wierckx, Nick; de Winde, Johannes H.; Ruijssenaars, Harald J.

    2010-01-01

    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. PMID:20194784

  6. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Holtze, Maria S. [Department of Natural Sciences, Soil and Environmental Chemistry, Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK-1871 Frederiksberg C (Denmark) and Department of Geochemistry, Geological Survey of Denmark and Greenland, Oster Voldgade 10, DK-1350 Copenhagen K (Denmark) and Section of Genetics and Microbiology, Department of Ecology, Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK-1871 Frederiksberg C (Denmark)]. E-mail: msh@geus.dk; Hansen, Hans Christian B. [Department of Natural Sciences, Soil and Environmental Chemistry, Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK-1871 Frederiksberg C (Denmark); Juhler, Rene K. [Department of Geochemistry, Geological Survey of Denmark and Greenland, Oster Voldgade 10, DK-1350 Copenhagen K (Denmark); Sorensen, Jan [Section of Genetics and Microbiology, Department of Ecology, Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK-1871 Frederiksberg C (Denmark); Aamand, Jens [Department of Geochemistry, Geological Survey of Denmark and Greenland, Oster Voldgade 10, DK-1350 Copenhagen K (Denmark)

    2007-07-15

    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.

  8. 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.

  9. p-Nitrophenol degradation by electro-Fenton process: Pathway, kinetic model and optimization using central composite design.

    Science.gov (United States)

    Meijide, J; Rosales, E; Pazos, M; Sanromán, M A

    2017-10-01

    The chemical process scale-up, from lab studies to industrial production, is challenging and requires deep knowledge of the kinetic model and the reactions that take place in the system. This knowledge is also useful in order to be employed for the reactor design and the determination of the optimal operational conditions. In this study, a model substituted phenol such as p-nitrophenol was degraded by electro-Fenton process and the reaction products yielded along the treatment were recorded. The kinetic model was developed using Matlab software and was based on main reactions that occurred until total mineralization which allowed predicting the degradation pathway under this advanced oxidation process. The predicted concentration profiles of p-nitrophenol, their intermediates and by-products in electro-Fenton process were validated with experimental assays and the results were consistent. Finally, based on the developed kinetic model the degradation process was optimized using central composite design taking as key parameters the ferrous ion concentration and current density. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. 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.

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

    International Nuclear Information System (INIS)

    Fabiańska, Aleksandra; Białk-Bielińska, Anna; Stepnowski, Piotr; Stolte, Stefan; Siedlecka, Ewa Maria

    2014-01-01

    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 2 SO 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

  12. 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

  13. Catabolite-mediated mutations in alternate toluene degradative pathways in Pseudomonas putida.

    Science.gov (United States)

    Leddy, M B; Phipps, D W; Ridgway, H F

    1995-01-01

    Pseudomonas putida 54g grew on mineral salts with toluene and exhibited catechol-2,3-dioxygenase (C23O) activity, indicating a meta pathway. After 10 to 15 days on toluene, nondegrading (Tol-) variants approached nearly 10% of total CFU. Auxotrophs were not detected among variants, suggesting selective loss of catabolic function(s). Variant formation was substrate dependent, since Tol- cells were observed on neither ethylbenzene, glucose, nor peptone-based media nor when toluene catabolism was suppressed by glucose. Unlike wild-type cells, variants did not grow on gasoline, toluene, benzene, ethylbenzene, benzoate, or catechol, suggesting loss of meta pathway function. Catabolic and C23O activities were restored to variants via transfer of a 78-mDa TOL-like plasmid from a wild-type Tol+ donor. Tests for reversion of variants to Tol+ were uniformly negative, suggesting possible delection or excision of catabolic genes. Deletions were confirmed in some variants by failure to hybridize with a DNA probe specific for the xylE gene encoding C23O. Cells grown on benzoate remained Tol+ but were C23O- and contained a plasmid of reduced size or were plasmid free, suggesting an alternate chromosomal catabolic pathway, also defective in variants. Cells exposed to benzyl alcohol, the initial oxidation product of toluene, accumulated > 13% variants in 5 days, even when cell division was repressed by nitrogen deprivation to abrogate selection processes. No variants formed in identical ethylbenzene-exposed controls. The results suggest that benzyl alcohol mediates irreversible defects in both a plasmid-associated meta pathway and an alternate chromosomal pathway. PMID:7642499

  14. Interacting signal pathways control defense gene expression in Arabidopsis in response to cell wall-degrading enzymes from Erwinia carotovora.

    Science.gov (United States)

    Norman-Setterblad, C; Vidal, S; Palva, E T

    2000-04-01

    We have characterized the role of salicylic acid (SA)-independent defense signaling in Arabidopsis thaliana in response to the plant pathogen Erwinia carotovora subsp. carotovora. Use of pathway-specific target genes as well as signal mutants allowed us to elucidate the role and interactions of ethylene, jasmonic acid (JA), and SA signal pathways in this response. Gene expression studies suggest a central role for both ethylene and JA pathways in the regulation of defense gene expression triggered by the pathogen or by plant cell wall-degrading enzymes (CF) secreted by the pathogen. Our results suggest that ethylene and JA act in concert in this regulation. In addition, CF triggers another, strictly JA-mediated response inhibited by ethylene and SA. SA does not appear to have a major role in activating defense gene expression in response to CF. However, SA may have a dual role in controlling CF-induced gene expression, by enhancing the expression of genes synergistically induced by ethylene and JA and repressing genes induced by JA alone.

  15. 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.

  16. Does tryptophan degradation along the kynurenine pathway mediate the association between pro-inflammatory immune activity and depressive symptoms?

    Science.gov (United States)

    Quak, Jacqueline; Doornbos, Bennard; Roest, Annelieke M; Duivis, Hester E; Vogelzangs, Nicole; Nolen, Willem A; Penninx, Brenda W J H; Kema, Ido P; de Jonge, Peter

    2014-07-01

    Several studies have suggested that induced tryptophan (TRP) degradation through the kynurenine (KYN) pathway by the enzyme indoleamine 2,3-dioxygenase (IDO) is implicated in the relation between depression and inflammation. We investigated the role of tryptophan degradation in the relationship between inflammatory markers and depressive symptoms in the Netherlands Study of Depression and Anxiety (NESDA) and hypothesized that tryptophan degradation would mediate (part of) this association. 2812 Participants of NESDA were included in this study including 1042 persons with current major depressive disorder (MDD). Assessments of C-reactive protein (CRP), interleukin (IL)-6, tumor-necrosis factor (TNF)-α, KYN and TRP were obtained from fasting blood samples at the baseline assessment. Tryptophan degradation was estimated by calculating the ratio [KYN/TRP]. Depressive symptoms were measured with the Inventory of Depressive Symptomatology. Significant associations between inflammation and depressive symptoms were found for CRP and IL-6, for the total group and the subgroup of patients with current MDD. Adjustment for KYN/TRP did not attenuate these associations. There were no significant indirect effects for CRP on depressive symptoms mediated by KYN/TRP for the whole group (B=-0.032; 95% CI: -0.103 to 0.028) and for the subgroup of patients with current MDD (B=0.059; 95% CI: -0.037 to 0.165). Also IL-6 did not indirectly affect depressive symptoms through KYN/TRP in the total group (B=-0.023; 95% CI: -0.093 to 0.045) and in the MDD subgroup B=0.052; 95% CI: -0.019 to 0.144). Finally, no significant relation between depressive symptoms and KYN/TRP was found in the whole group (β=-0.019, p=0.311) nor in the subgroup with MDD (β=0.025, p=0.424). We did not find indications for tryptophan degradation, measured by KYN/TRP, to mediate the relationship between inflammation and depressive symptoms. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Trafficking and degradation pathways in pathogenic conversion of prions and prion-like proteins in neurodegenerative diseases.

    Science.gov (United States)

    Victoria, Guiliana Soraya; Zurzolo, Chiara

    2015-09-02

    Several neurodegenerative diseases such as transmissible spongiform encephalopathies, Alzheimer's and Parkinson's diseases are caused by the conversion of cellular proteins to a pathogenic conformer. Despite differences in the primary structure and subcellular localization of these proteins, which include the prion protein, α-synuclein and amyloid precursor protein (APP), striking similarity has been observed in their ability to seed and convert naïve protein molecules as well as transfer between cells. This review aims to cover what is known about the intracellular trafficking of these proteins as well as their degradation mechanisms and highlight similarities in their movement through the endocytic pathway that could contribute to the pathogenic conversion and seeding of these proteins which underlies the basis of these diseases. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. 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.

  19. Crystallization and preliminary X-ray analysis of AAMS amidohydrolase, the final enzyme in degradation pathway I of pyridoxine

    International Nuclear Information System (INIS)

    Kobayashi, Jun; Yoshida, Hiromi; Chu, Huy Nhat; Yoshikane, Yu; Kamitori, Shigehiro; Yagi, Toshiharu

    2009-01-01

    Recombinant α-(N-acetylaminomethylene)succinic acid amidohydrolase from M. loti MAFF303099 was crystallized and diffraction data were collected at 2.7 Å resolution. α-(N-Acetylaminomethylene)succinic acid (AAMS) amidohydrolase from Mesorhizobium loti MAFF303099, which is involved in a degradation pathway of vitamin B 6 and catalyzes the degradation of AAMS to acetic acid, ammonia, carbon dioxide and succinic semialdehyde, has been overexpressed in Escherichia coli. To elucidate the reaction mechanism based on the tertiary structure, the recombinant enzyme was purified and crystallized by the sitting-drop vapour-diffusion method using PEG 8000 as precipitant. A crystal of the enzyme belonged to the monoclinic space group C2, with unit-cell parameters a = 393.2, b = 58.3, c = 98.9 Å, β = 103.4°, and diffraction data were collected to 2.7 Å resolution. The V M value and calculation of the self-rotation function suggested that three dimers with a threefold symmetry were possibly present in the asymmetric unit

  20. 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.

  1. Degradation of a cationic dye (Rhodamine 6G) using hydrodynamic cavitation coupled with other oxidative agents: Reaction mechanism and pathway.

    Science.gov (United States)

    Rajoriya, Sunil; Bargole, Swapnil; Saharan, Virendra Kumar

    2017-01-01

    In the present study, decolorization and mineralization of a cationic dye, Rhodamine 6G (Rh6G), has been carried out using hydrodynamic cavitation (HC). Two cavitating devices such as slit and circular venturi were used to generate cavitation in HC reactor. The process parameters such as initial dye concentration, solution pH, operating inlet pressure, and cavitation number were investigated in detail to evaluate their effects on the decolorization efficiency of Rh6G. Decolorization of Rh6G was marginally higher in the case of slit venturi as compared to circular venturi. The kinetic study showed that decolorization and mineralization of the dye fitted first-order kinetics. The loadings of H 2 O 2 and ozone have been optimized to intensify the decolorization and mineralization efficiency of Rh6G using HC. Nearly 54% decolorization of Rh6G was obtained using a combination of HC and H 2 O 2 at a dye to H 2 O 2 molar ratio of 1:30. The combination of HC with ozone resulted in 100% decolorization in almost 5-10min of processing time depending upon the initial dye concentration. To quantify the extent of mineralization, total organic carbon (TOC) analysis was also performed using various processes and almost 84% TOC removal was obtained using HC coupled with 3g/h of ozone. The degradation by-products formed during the complete degradation process were qualitatively identified by liquid chromatography-mass spectrometry (LC-MS) and a detailed degradation pathway has been proposed. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Degradation of sulfadimethoxine catalyzed by laccase with soybean meal extract as natural mediator: Mechanism and reaction pathway.

    Science.gov (United States)

    Liang, Shangtao; Luo, Qi; Huang, Qingguo

    2017-08-01

    Natural laccase-mediator systems have been well recognized as an eco-friendly and energy-saving approach in environmental remediation, whose further application is however limited by the high cost of natural mediators and relatively long treatment time span. This study evaluated the water extract of soybean meal, a low-cost compound system, in mediating the laccase catalyzed degradation of a model contaminant of emerging concern, sulfadimethoxine (SDM), and demonstrated it as a promising alternative mediator for soil and water remediation. Removal of 73.3% and 65.6% was achieved in 9 h using soybean meal extract (SBE) as the mediating system for laccase-catalyzed degradation of sulfadimethoxine at the concentration of 1 ppm and 10 ppm, respectively. Further degradation of sulfadimethoxine was observed with multiple SBE additions. Using SBE as mediator increased the 9-h removal of SDM at 1 ppm initial concentration by 52.9%, 49.4%, and 36.3% in comparison to the system mediated by 1-Hydroxybenzotriazole (HBT), p-Coumaric acid (COU) and 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonate) (ABTS), respectively. With the detection of stable coupling products formed with radical scavenger (5,5-Dimethyl-1-pyrroline N-oxide, DMPO), three phenolic compounds (vanillin, apocynin, and daidzein) in SBE were confirmed to serve as mediators for Trametes versicolor laccase. Reaction pathways were proposed based on the results of High Resolution Mass Spectrometry. SO 2 excursion happened during SDM transformation, leading to elimination of antimicrobial activity. Therefore, as a natural, phenol rich, and affordable compound system, the future application of SBE in wastewater and soil remediation is worth exploring. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. NIK is required for NF-κB-mediated induction of BAG3 upon inhibition of constitutive protein degradation pathways.

    Science.gov (United States)

    Rapino, F; Abhari, B A; Jung, M; Fulda, S

    2015-03-12

    Recently, we reported that induction of the co-chaperone Bcl-2-associated athanogene 3 (BAG3) is critical for recovery of rhabdomyosarcoma (RMS) cells after proteotoxic stress upon inhibition of the two constitutive protein degradation pathways, that is, the ubiquitin-proteasome system by Bortezomib and the aggresome-autophagy system by histone deacetylase 6 (HDAC6) inhibitor ST80. In the present study, we investigated the molecular mechanisms mediating BAG3 induction under these conditions. Here, we identify nuclear factor-kappa B (NF-κB)-inducing kinase (NIK) as a key mediator of ST80/Bortezomib-stimulated NF-κB activation and transcriptional upregulation of BAG3. ST80/Bortezomib cotreatment upregulates mRNA and protein expression of NIK, which is accompanied by an initial increase in histone H3 acetylation. Importantly, NIK silencing by siRNA abolishes NF-κB activation and BAG3 induction by ST80/Bortezomib. Furthermore, ST80/Bortezomib cotreatment stimulates NF-κB transcriptional activity and upregulates NF-κB target genes. Genetic inhibition of NF-κB by overexpression of dominant-negative IκBα superrepressor (IκBα-SR) or by knockdown of p65 blocks the ST80/Bortezomib-stimulated upregulation of BAG3 mRNA and protein expression. Interestingly, inhibition of lysosomal activity by Bafilomycin A1 inhibits ST80/Bortezomib-stimulated IκBα degradation, NF-κB activation and BAG3 upregulation, indicating that IκBα is degraded via the lysosome in the presence of Bortezomib. Thus, by demonstrating a critical role of NIK in mediating NF-κB activation and BAG3 induction upon ST80/Bortezomib cotreatment, our study provides novel insights into mechanisms of resistance to proteotoxic stress in RMS.

  4. Biphenyl-Metabolizing Bacteria in the Rhizosphere of Horseradish and Bulk Soil Contaminated by Polychlorinated Biphenyls as Revealed by Stable Isotope Probing▿ †

    Science.gov (United States)

    Uhlik, Ondrej; Jecna, Katerina; Mackova, Martina; Vlcek, Cestmir; Hroudova, Miluse; Demnerova, Katerina; Paces, Vaclav; Macek, Tomas

    2009-01-01

    DNA-based stable isotope probing in combination with terminal restriction fragment length polymorphism was used in order to identify members of the microbial community that metabolize biphenyl in the rhizosphere of horseradish (Armoracia rusticana) cultivated in soil contaminated with polychlorinated biphenyls (PCBs) compared to members of the microbial community in initial, uncultivated bulk soil. On the basis of early and recurrent detection of their 16S rRNA genes in clone libraries constructed from [13C]DNA, Hydrogenophaga spp. appeared to dominate biphenyl catabolism in the horseradish rhizosphere soil, whereas Paenibacillus spp. were the predominant biphenyl-utilizing bacteria in the initial bulk soil. Other bacteria found to derive carbon from biphenyl in this nutrient-amended microcosm-based study belonged mostly to the class Betaproteobacteria and were identified as Achromobacter spp., Variovorax spp., Methylovorus spp., or Methylophilus spp. Some bacteria that were unclassified at the genus level were also detected, and these bacteria may be members of undescribed genera. The deduced amino acid sequences of the biphenyl dioxygenase α subunits (BphA) from bacteria that incorporated [13C]into DNA in 3-day incubations of the soils with [13C]biphenyl are almost identical to that of Pseudomonas alcaligenes B-357. This suggests that the spectrum of the PCB congeners that can be degraded by these enzymes may be similar to that of strain B-357. These results demonstrate that altering the soil environment can result in the participation of different bacteria in the metabolism of biphenyl. PMID:19700551

  5. Polysorbates 20 and 80 used in the formulation of protein biotherapeutics: structure and degradation pathways.

    Science.gov (United States)

    Kerwin, Bruce A

    2008-08-01

    Polysorbates 20 and 80 (Tween 20 and Tween 80) are used in the formulation of biotherapeutic products for both preventing surface adsorption and as stabilizers against protein aggregation. The polysorbates are amphipathic, nonionic surfactants composed of fatty acid esters of polyoxyethylene sorbitan being polyoxyethylene sorbitan monolaurate for polysorbate 20 and polyoxyethylene sorbitan monooleate for polysorbate 80. The polysorbates used in the formulation of biopharmaceuticals are mixtures of different fatty acid esters with the monolaurate fraction of polysorbate 20 making up only 40-60% of the mixture and the monooleate fraction of polysorbate 80 making up >58% of the mixture. The polysorbates undergo autooxidation, cleavage at the ethylene oxide subunits and hydrolysis of the fatty acid ester bond. Autooxidation results in hydroperoxide formation, side-chain cleavage and eventually formation of short chain acids such as formic acid all of which could influence the stability of a biopharmaceutical product. Oxidation of the fatty acid moiety while well described in the literature has not been specifically investigated for polysorbate. This review focuses on the chemical structure of the polysorbates, factors influencing micelle formation and factors and excipients influencing stability and degradation of the polyoxyethylene and fatty acid ester linkages.

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

    Science.gov (United States)

    Scoma, Alberto; Barbato, Marta; Hernandez-Sanabria, Emma; Mapelli, Francesca; Daffonchio, Daniele; Borin, Sara; Boon, Nico

    2016-01-01

    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. PMID:27020120

  7. 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.

  8. 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.

  9. Degradation of Organic UV filters in Chlorinated Seawater Swimming Pools: Transformation Pathways and Bromoform Formation.

    Science.gov (United States)

    Manasfi, Tarek; Coulomb, Bruno; Ravier, Sylvain; Boudenne, Jean-Luc

    2017-12-05

    Organic ultraviolet (UV) filters are used in sunscreens and other personal-care products to protect against harmful effects of exposure to UV solar radiation. Little is known about the fate of UV filters in seawater swimming pools disinfected with chlorine. The present study investigated the occurrence and fate of five commonly used organic UV filters, namely dioxybenzone, oxybenzone, avobenzone, 2-ethylhexyl-4-methoxycinnamate, and octocrylene, in chlorinated seawater swimming pools. Pool samples were collected to monitor the variation of UV filter concentrations during pool opening hours. Furthermore, laboratory-controlled chlorination experiments were conducted in seawater spiked with UV filters to investigate the reactivity of UV filters. Extracts of chlorination reaction samples were analyzed using high-resolution mass spectrometry and electron-capture detection to identify the potentially formed byproducts. In the collected pool samples, all the UV filters except dioxybenzone were detected. Chlorination reactions showed that only octocrylene was stable in chlorinated seawater. The four reactive UV filters generated brominated transformation products and disinfection byproducts. This formation of brominated products resulted from reactions between the reactive UV filters and bromine, which is formed rapidly when chlorine is added to seawater. Based on the identified byproducts, the transformation pathways of the reactive UV filters were proposed for the first time. Bromoform was generated by all the reactive UV filters at different yields. Bromal hydrate was also detected as one of the byproducts generated by oxybenzone and dioxybenzone.

  10. 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.

  11. 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"2"0"2Hg and Δ"1"9"9Hg) 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"2"0"2Hg (− 1.69 to − 0.20‰) reflecting the heterogeneity of Hg mining sources in sediment. The δ"2"0"2Hg 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"2"0"2Hg and Δ"1"9"9Hg) 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"2"0"2Hg of pre-photodegraded MMHg and sediment IHg. Cache Creek had mass dependent fractionation (MDF; δ"2"0"2Hg) 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.

  12. Thermal decomposition of biphenyl (1963); Decomposition thermique du biphenyle (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Clerc, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1962-06-15

    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) [French] Les vitesses de formation des produits de decomposition du biphenyle: hydrogene, methane, ethane, ethylene, ainsi que des triphenyles, ont ete mesurees en phase vapeur et en phase liquide a 460 deg. C. L'etude des produits de decomposition du biphenyle a differentes temperatures comprises entre 400 et 460 deg. C, a fourni les valeurs des energies d'activation des reactions conduisant aux principaux produits de la pyrolyse en phase vapeur. Produit et Energie d'activation: Hydrogene 73 {+-} 2 kcal/Mole; Benzene 76 {+-} 2 kcal/Mole; Metatriphenyle, 53 {+-} 2 kcal/Mole; Decomposition du biphenyle 64 {+-} 2 kcal/Mole; La

  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.

    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

  14. 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.

  15. 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.

  16. Fibrin(ogen) is internalized and degraded by activated human monocytoid cells via Mac-1 (CD11b/CD18): a nonplasmin fibrinolytic pathway.

    Science.gov (United States)

    Simon, D I; Ezratty, A M; Francis, S A; Rennke, H; Loscalzo, J

    1993-10-15

    Fibrin(ogen) (FGN) is important for hemostasis and wound healing and is cleared from sites of injury primarily by the plasminogen activator system. However, there is emerging evidence in plasminogen activator-deficient transgenic mice that nonplasmin pathways may be important in fibrin(ogen)olysis, as well. Given the proximity of FGN and monocytes within the occlusive thrombus at sites of vascular injury, we considered the possibility that monocytes may play an ancillary role in the degradation and clearance of fibrin. We found that monocytes possess an alternative fibrinolytic pathway that uses the integrin Mac-1, which directly binds and internalizes FGN, resulting in its lysosomal degradation. At 4 degrees C, FGN binds to U937 monocytoid cells in a specific and saturable manner with a kd of 1.8 mumol/L. Binding requires adenosine diphosphate stimulation and is calcium-dependent. At 37 degrees C, FGN and fibrin monomer (FM) are internalized and degraded at rates of 0.37 +/- 0.13 and 0.55 +/- 0.03 microgram/10(6) cells/h by U937 cells, 1.38 +/- 0.02 and 1.20 +/- 0.30 microgram/10(6) cells/h by THP-1 cells, and 2.10 +/- 0.20 and 2.52 +/- 0.18 micrograms/10(6) cells/h by human peripheral blood mononuclear cells, respectively. The serine protease inhibitors, PPACK and aprotinin, and the specific elastase inhibitor, AAPVCK, do not significantly inhibit degradation. However, degradation is inhibited by chloroquine, suggesting that a lysosomal pathway is involved. Factor X, a competitive ligand with FGN for the Mac-1 receptor, also blocks degradation, as does a monoclonal antibody to the alpha-subunit of Mac-1. Autoradiography of radioiodinated, internalized FGN shows that FGN proteolysis by the pathway produces a unique degradation pattern distinct from that observed with plasmin. In a fibrin clot lysis assay, Mac-1-mediated fibrinolysis contributed significantly to total fibrinolysis. In summary, FGN is internalized and degraded by activated human monocytoid cells via

  17. Putative pathway of sex pheromone biosynthesis and degradation by expression patterns of genes identified from female pheromone gland and adult antenna of Sesamia inferens (Walker).

    Science.gov (United States)

    Zhang, Ya-Nan; Xia, Yi-Han; Zhu, Jia-Yao; Li, Sheng-Yun; Dong, Shuang-Lin

    2014-05-01

    The general pathway of biosynthesis and degradation for Type-I sex pheromones in moths is well established, but some genes involved in this pathway remain to be characterized. The purple stem borer, Sesamia inferens, employs a pheromone blend containing components with three different terminal functional groups (Z11-16:OAc, Z11-16:OH, and Z11-16:Ald) of Type-I sex pheromones. Thus, it provides a good model to study the diversity of genes involved in pheromone biosynthesis and degradation pathways. By analyzing previously obtained transcriptomic data of the sex pheromone glands and antennae, we identified 73 novel genes that are possibly related to pheromone biosynthesis (46 genes) or degradation (27 genes). Gene expression patterns and phylogenetic analysis revealed that one desaturase (SinfDes4), one fatty acid reductase (SinfFAR2), and one fatty acid xtransport protein (SinfFATP1) genes were predominantly expressed in pheromone glands, and clustered with genes involved in pheromone synthesis in other moth species. Ten genes including five carboxylesterases (SinfCXE10, 13, 14, 18, and 20), three aldehyde oxidases (SinfAOX1, 2 and 3), and two alcohol dehydrogenases (SinfAD1 and 3) were expressed specifically or predominantly in antennae, and could be candidate genes involved in pheromone degradation. SinfAD1 and 3 are the first reported alcohol dehydrogenase genes with antennae-biased expression. Based on these results we propose a pathway involving these potential enzyme-encoding gene candidates in sex pheromone biosynthesis and degradation in S. inferens. This study provides robust background information for further elucidation of the genetic basis of sex pheromone biosynthesis and degradation, and ultimately provides potential targets to disrupt sexual communication in S. inferens for control purposes.

  18. 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

  19. 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

  20. 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.

  1. Chemotaxis and degradation of organophosphate compound by a novel moderately thermo-halo tolerant Pseudomonas sp. strain BUR11: evidence for possible existence of two pathways for degradation

    OpenAIRE

    Pailan, Santanu; Saha, Pradipta

    2015-01-01

    An organophosphate (OP) degrading chemotactic bacterial strain BUR11 isolated from an agricultural field was identified as a member of Pseudomonas genus on the basis of its 16S rRNA gene sequence. The strain could utilize parathion, chlorpyrifos and their major hydrolytic intermediates as sole source of carbon for its growth and exhibited positive chemotactic response towards most of them. Optimum concentration of parathion for its growth was recorded to be 200 ppm and 62% of which was degrad...

  2. Photolysis of model emerging contaminants in ultra-pure water: kinetics, by-products formation and degradation pathways.

    Science.gov (United States)

    Benitez, F Javier; Acero, Juan L; Real, Francisco J; Roldan, Gloria; Rodriguez, Elena

    2013-02-01

    The photolysis of five frequent emerging contaminants (Benzotriazole, Chlorophene, N,N-diethyl-m-toluamide or DEET, Methylindole, and Nortriptyline HCl) was investigated in ultrapure water under monochromatic ultraviolet radiation at 254 nm and by a combination of UV and hydrogen peroxide. The results revealed that the photolysis rates followed first-order kinetics, with rate constant values depending on the nature of the specific compound, the pH, and the presence or absence of the scavenger tert-butanol. Quantum yields were also determined and values in the range of 53.8 × 10⁻³ - 9.4 × 10⁻³ mol E⁻¹ for Benzotriazole, 525 × 10⁻³ - 469 × 10⁻³ mol E⁻¹ for Chlorophene, 2.8 × 10⁻³ - 0.9 × 10⁻³ mol E⁻¹ for DEET, 108 × 10⁻³ - 165 × 10⁻³ mol E⁻¹ for Methylindole, and 13.8 × 10⁻³ - 15.0 × 10⁻³ mol E⁻¹ for Nortriptyline were obtained. The study also found that the UV/H₂O₂ process enhanced the oxidation rate in comparison to direct photolysis. High-performance liquid chromatography coupled to electrospray ionization quadrupole time-of-flight mass spectrometry (HPLC-ESI-QTOF-MS) technique was applied to the concentrations evaluation and further identification of the parent compounds and their by-products, which allowed the proposal of the degradation pathways for each compound. Finally, in order to assess the aquatic toxicity in the photodegradation of these compounds, the Vibrio fischeri acute toxicity test was used, and the results indicated an initial increase of this parameter in all cases, followed by a decrease in the specific case of Benzotriazole, DEET, Methylindole, and Chlorophene. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Sulfamethoxazole in poultry wastewater: Identification, treatability and degradation pathway determination in a membrane-photocatalytic slurry reactor.

    Science.gov (United States)

    Asha, Raju C; Kumar, Mathava

    2015-01-01

    The presence of sulfamethoxazole (SMX) in a real-time poultry wastewater was identified via HPLC analysis. Subsequently, SMX removal from the poultry wastewater was investigated using a continuous-mode membrane-photocatalytic slurry reactor (MPSR). The real-time poultry wastewater was found to have an SMX concentration of 0-2.3 mg L(-1). A granular activated carbon supported TiO2 (GAC-TiO2) was synthesized, characterized and used in MPSR experiments. The optimal MPSR condition, i.e., HRT ∼ 125 min and catalyst dosage 529.3 mg L(-1), for complete SMX removal was found out using unconstrained optimization technique. Under the optimized condition, the effect of SMX concentration on MPSR performance was investigated by synthetic addition of SMX (i.e., 1, 25, 50, 75 and 100 mg L(-1)) into the wastewater. Interestingly, complete removals of total volatile solids (TVS), biochemical oxygen demand (BOD) and SMX were observed under all SMX concentrations investigated. However, a decline in SMX removal rate and proportionate increase in transmembrane-pressure (TMP) were observed when the SMX concentration was increased to higher levels. In the MPSR, the SMX mineralization was through one of the following degradation pathways: (i) fragmentation of the isoxazole ring and (ii) the elimination of methyl and amide moieties followed by the formation of phenyl sulfinate ion. These results show that the continuous-mode MPSR has great potential in the removal for SMX contaminated real-time poultry wastewater and similar organic micropollutants from wastewater.

  4. 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

  5. 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/...

  6. 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

  7. 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.

  8. 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.

  9. α-Amino acid containing degradable polymers as functional biomaterials: rational design, synthetic pathway, and biomedical applications.

    Science.gov (United States)

    Sun, Huanli; Meng, Fenghua; Dias, Aylvin A; Hendriks, Marc; Feijen, Jan; Zhong, Zhiyuan

    2011-06-13

    Currently, biomedical engineering is rapidly expanding, especially in the areas of drug delivery, gene transfer, tissue engineering, and regenerative medicine. A prerequisite for further development is the design and synthesis of novel multifunctional biomaterials that are biocompatible and biologically active, are biodegradable with a controlled degradation rate, and have tunable mechanical properties. In the past decades, different types of α-amino acid-containing degradable polymers have been actively developed with the aim to obtain biomimicking functional biomaterials. The use of α-amino acids as building units for degradable polymers may offer several advantages: (i) imparting chemical functionality, such as hydroxyl, amine, carboxyl, and thiol groups, which not only results in improved hydrophilicity and possible interactions with proteins and genes, but also facilitates further modification with bioactive molecules (e.g., drugs or biological cues); (ii) possibly improving materials biological properties, including cell-materials interactions (e.g., cell adhesion, migration) and degradability; (iii) enhancing thermal and mechanical properties; and (iv) providing metabolizable building units/blocks. In this paper, recent developments in the field of α-amino acid-containing degradable polymers are reviewed. First, synthetic approaches to prepare α-amino acid-containing degradable polymers will be discussed. Subsequently, the biomedical applications of these polymers in areas such as drug delivery, gene delivery and tissue engineering will be reviewed. Finally, the future perspectives of α-amino acid-containing degradable polymers will be evaluated.

  10. 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.

  11. Interaction between Wnt/β-catenin and RAS-ERK pathways and an anti-cancer strategy via degradations of β-catenin and RAS by targeting the Wnt/β-catenin pathway.

    Science.gov (United States)

    Jeong, Woo-Jeong; Ro, Eun Ji; Choi, Kang-Yell

    2018-01-01

    Aberrant activation of the Wnt/β-catenin and RAS-extracellular signal-regulated kinase (ERK) pathways play important roles in the tumorigenesis of many different types of cancer, most notably colorectal cancer (CRC). Genes for these two pathways, such as adenomatous polyposis coli ( APC ) and KRAS are frequently mutated in human CRC, and involved in the initiation and progression of the tumorigenesis, respectively. Moreover, recent studies revealed interaction of APC and KRAS mutations in the various stages of colorectal tumorigenesis and even in metastasis accompanying activation of the cancer stem cells (CSCs). A key event in the synergistic cooperation between Wnt/β-catenin and RAS-ERK pathways is a stabilization of both β-catenin and RAS especially mutant KRAS by APC loss, and pathological significance of this was indicated by correlation of increased β-catenin and RAS levels in human CRC where APC mutations occur as high as 90% of CRC patients. Together with the notion of the protein activity reduction by lowering its level, inhibition of both β-catenin and RAS especially by degradation could be a new ideal strategy for development of anti-cancer drugs for CRC. In this review, we will discuss interaction between the Wnt/β-catenin and RAS-ERK pathways in the colorectal tumorigenesis by providing the mechanism of RAS stabilization by aberrant activation of Wnt/β-catenin. We will also discuss our small molecular anti-cancer approach controlling CRC by induction of specific degradations of both β-catenin and RAS via targeting Wnt/β-catenin pathway especially for the KYA1797K, a small molecule specifically binding at the regulator of G-protein signaling (RGS)-domain of Axin.

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

    KAUST Repository

    Scoma, Alberto; Barbato, Marta; Hernandez-Sanabria, Emma; Mapelli, Francesca; Daffonchio, Daniele; Borin, Sara; Boon, Nico

    2016-01-01

    . 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

  13. 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...

  14. 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...

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

    OpenAIRE

    Koopman, F.; Wierckx, N.; Winde, de, J.H.; Ruijssenaars, H.J.

    2010-01-01

    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 an...

  16. 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.

  17. 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

  18. 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

  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

    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

  20. The homogentisate pathway: a central catabolic pathway involved in the degradation of L-phenylalanine, L-tyrosine, and 3-hydroxyphenylacetate in Pseudomonas putida.

    Science.gov (United States)

    Arias-Barrau, Elsa; Olivera, Elías R; Luengo, José M; Fernández, Cristina; Galán, Beatriz; García, José L; Díaz, Eduardo; Miñambres, Baltasar

    2004-08-01

    Pseudomonas putida metabolizes Phe and Tyr through a peripheral pathway involving hydroxylation of Phe to Tyr (PhhAB), conversion of Tyr into 4-hydroxyphenylpyruvate (TyrB), and formation of homogentisate (Hpd) as the central intermediate. Homogentisate is then catabolized by a central catabolic pathway that involves three enzymes, homogentisate dioxygenase (HmgA), fumarylacetoacetate hydrolase (HmgB), and maleylacetoacetate isomerase (HmgC), finally yielding fumarate and acetoacetate. Whereas the phh, tyr, and hpd genes are not linked in the P. putida genome, the hmgABC genes appear to form a single transcriptional unit. Gel retardation assays and lacZ translational fusion experiments have shown that hmgR encodes a specific repressor that controls the inducible expression of the divergently transcribed hmgABC catabolic genes, and homogentisate is the inducer molecule. Footprinting analysis revealed that HmgR protects a region in the Phmg promoter that spans a 17-bp palindromic motif and an external direct repetition from position -16 to position 29 with respect to the transcription start site. The HmgR protein is thus the first IclR-type regulator that acts as a repressor of an aromatic catabolic pathway. We engineered a broad-host-range mobilizable catabolic cassette harboring the hmgABC, hpd, and tyrB genes that allows heterologous bacteria to use Tyr as a unique carbon and energy source. Remarkably, we show here that the catabolism of 3-hydroxyphenylacetate in P. putida U funnels also into the homogentisate central pathway, revealing that the hmg cluster is a key catabolic trait for biodegradation of a small number of aromatic compounds.

  1. Paracetamol - toxicity and microbial utilization. Pseudomonas moorei KB4 as a case study for exploring degradation pathway.

    Science.gov (United States)

    Żur, Joanna; Wojcieszyńska, Danuta; Hupert-Kocurek, Katarzyna; Marchlewicz, Ariel; Guzik, Urszula

    2018-09-01

    Paracetamol, a widely used analgesic and antipyretic drug, is currently one of the most emerging pollutants worldwide. Besides its wide prevalence in the literature only several bacterial strains able to degrade this compound have been described. In this study, we isolated six new bacterial strains able to remove paracetamol. The isolated strains were identified as the members of Pseudomonas, Bacillus, Acinetobacter and Sphingomonas genera and characterized phenotypically and biochemically using standard methods. From the isolated strains, Pseudomonas moorei KB4 was able to utilize 50 mg L -1 of paracetamol. As the main degradation products, p-aminophenol and hydroquinone were identified. Based on the measurements of specific activity of acyl amidohydrolase, deaminase and hydroquinone 1,2-dioxygenase and the results of liquid chromatography analyses, we proposed a mechanism of paracetamol degradation by KB4 strain under co-metabolic conditions with glucose. Additionally, toxicity bioassays and the influence of various environmental factors, including pH, temperature, heavy metals at no-observed-effective-concentrations, and the presence of aromatic compounds on the efficiency and mechanism of paracetamol degradation by KB4 strain were determined. This comprehensive study about paracetamol biodegradation will be helpful in designing a treatment systems of wastewaters contaminated with paracetamol. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Laboratory evaluation of polychlorinated biphenyls ...

    Science.gov (United States)

    Effectiveness and limitations of the encapsulation method for reducing polychlorinated biphenyls (PCBs) concentrations in indoor air and contaminated surface have been evaluated in the laboratory study. Ten coating materials such as epoxy and polyurethane coatings, latex paint, and petroleum-based paint were tested in small environmental chambers to rank the encapsulants by their resistance to PCB sorption and estimate the key parameters required by a barrier model. Wipe samples were collected from PCB contaminated surface encapsulated with the coating materials to rank the encapsulants by their resistance to PCB migration from the source. A barrier model was used to calculate the PCB concentrations in the sources and the encapsulant layers, and at the exposed surfaces of the encapsulant and in the room air at different times. The performance of the encapsulants was ranked by those concentrations and PCB percent reductions. Overall, the three epoxy coatings performed better than the other coatings. Both the experimental results and the mathematical modeling showed that selecting proper encapsulants can effectively reduce the PCB concentrations at the exposed surfaces. The encapsulation method is most effective for contaminated surfaces that contain low levels of PCBs. This study answers some of these questions by using a combination of laboratory testing and mathematical modeling. The results should be useful to mitigation engineers, building owners and managers

  3. Structurally simplified biphenyl combretastatin A4 derivatives retain in vitro anti-cancer activity dependent on mitotic arrest

    Science.gov (United States)

    Tarade, Daniel; Ma, Dennis; Pignanelli, Christopher; Mansour, Fadi; Simard, Daniel; van den Berg, Sean; Gauld, James; McNulty, James; Pandey, Siyaram

    2017-01-01

    The cis-stilbene, combretastatin A4 (CA4), is a potent microtubule targeting and vascular damaging agent. Despite promising results at the pre-clinical level and extensive clinical evaluation, CA4 has yet to be approved for therapeutic use. One impediment to the development of CA4 is an inherent conformational instability about the ethylene linker, which joins two aromatic rings. We have previously published preliminary data regarding structurally simplified biphenyl derivatives of CA4, lacking an ethylene linker, which retain anti-proliferative and pro-apoptotic activity, albeit at higher doses. Our current study provides a more comprehensive evaluation regarding the anti-proliferative and pro-apoptotic properties of biphenyl CA4 derivatives in both 2D and 3D cancerous and non-cancerous cell models. Computational analysis has revealed that cytotoxicity of CA4 and biphenyl analogues correlates with predicted tubulin affinity. Additional mechanistic evaluation of the biphenyl derivatives found that their anti-cancer activity is dependent on prolonged mitotic arrest, in a similar manner to CA4. Lastly, we have shown that cancer cells deficient in the extrinsic pathway of apoptosis experience delayed cell death following treatment with CA4 or analogues. Biphenyl derivatives of CA4 represent structurally simplified analogues of CA4, which retain a similar mechanism of action. The biphenyl analogues warrant in vivo examination to evaluate their potential as vascular damaging agents. PMID:28253265

  4. Structurally simplified biphenyl combretastatin A4 derivatives retain in vitro anti-cancer activity dependent on mitotic arrest.

    Directory of Open Access Journals (Sweden)

    Daniel Tarade

    Full Text Available The cis-stilbene, combretastatin A4 (CA4, is a potent microtubule targeting and vascular damaging agent. Despite promising results at the pre-clinical level and extensive clinical evaluation, CA4 has yet to be approved for therapeutic use. One impediment to the development of CA4 is an inherent conformational instability about the ethylene linker, which joins two aromatic rings. We have previously published preliminary data regarding structurally simplified biphenyl derivatives of CA4, lacking an ethylene linker, which retain anti-proliferative and pro-apoptotic activity, albeit at higher doses. Our current study provides a more comprehensive evaluation regarding the anti-proliferative and pro-apoptotic properties of biphenyl CA4 derivatives in both 2D and 3D cancerous and non-cancerous cell models. Computational analysis has revealed that cytotoxicity of CA4 and biphenyl analogues correlates with predicted tubulin affinity. Additional mechanistic evaluation of the biphenyl derivatives found that their anti-cancer activity is dependent on prolonged mitotic arrest, in a similar manner to CA4. Lastly, we have shown that cancer cells deficient in the extrinsic pathway of apoptosis experience delayed cell death following treatment with CA4 or analogues. Biphenyl derivatives of CA4 represent structurally simplified analogues of CA4, which retain a similar mechanism of action. The biphenyl analogues warrant in vivo examination to evaluate their potential as vascular damaging agents.

  5. Degradation of lipid regulators by the UV/chlorine process: Radical mechanisms, chlorine oxide radical (ClO•)-mediated transformation pathways and toxicity changes.

    Science.gov (United States)

    Kong, Xiujuan; Wu, Zihao; Ren, Ziran; Guo, Kaiheng; Hou, Shaodong; Hua, Zhechao; Li, Xuchun; Fang, Jingyun

    2018-06-15

    Degradation of three lipid regulators, i.e., gemfibrozil, bezafibrate and clofibric acid, by a UV/chlorine treatment was systematically investigated. The chlorine oxide radical (ClO • ) played an important role in the degradation of gemfibrozil and bezafibrate with second-order rate constants of 4.2 (±0.3) × 10 8  M -1  s -1 and 3.6 (±0.1) × 10 7  M -1  s -1 , respectively, whereas UV photolysis and the hydroxyl radical (HO • ) mainly contributed to the degradation of clofibric acid. The first-order rate constants (k') for the degradation of gemfibrozil and bezafibrate increased linearly with increasing chlorine dosage, primarily due to the linear increase in the ClO • concentration. The k' values for gemfibrozil, bezafibrate, and clofibric acid degradation decreased with increasing pH from 5.0 to 8.4; however, the contribution of the reactive chlorine species (RCS) increased. Degradation of gemfibrozil and bezafibrate was enhanced in the presence of Br - , whereas it was inhibited in the presence of natural organic matter (NOM). The presence of ammonia at a chlorine: ammonia molar ratio of 1:1 resulted in decreases in the k' values for gemfibrozil and bezafibrate of 69.7% and 7%, respectively, but led to an increase in that for clofibric acid of 61.8%. Degradation of gemfibrozil by ClO • was initiated by hydroxylation and chlorine substitution on the benzene ring. Then, subsequent hydroxylation, bond cleavage and chlorination reactions led to the formation of more stable products. Three chlorinated intermediates were identified during ClO • oxidation process. Formation of the chlorinated disinfection by-products chloral hydrate and 1,1,1-trichloropropanone was enhanced relative to that of other by-products. The acute toxicity of gemfibrozil to Vibrio fischeri increased significantly when subjected to direct UV photolysis, whereas it decreased when oxidized by ClO • . This study is the first to report the transformation pathway of a

  6. Unique nonstructural proteins of Pneumonia Virus of Mice (PVM) promote degradation of interferon (IFN) pathway components and IFN-stimulated gene proteins.

    Science.gov (United States)

    Dhar, Jayeeta; Barik, Sailen

    2016-12-01

    Pneumonia Virus of Mice (PVM) is the only virus that shares the Pneumovirus genus of the Paramyxoviridae family with Respiratory Syncytial Virus (RSV). A deadly mouse pathogen, PVM has the potential to serve as a robust animal model of RSV infection, since human RSV does not fully replicate the human pathology in mice. Like RSV, PVM also encodes two nonstructural proteins that have been implicated to suppress the IFN pathway, but surprisingly, they exhibit no sequence similarity with their RSV equivalents. The molecular mechanism of PVM NS function, therefore, remains unknown. Here, we show that recombinant PVM NS proteins degrade the mouse counterparts of the IFN pathway components. Proteasomal degradation appears to be mediated by ubiquitination promoted by PVM NS proteins. Interestingly, NS proteins of PVM lowered the levels of several ISG (IFN-stimulated gene) proteins as well. These results provide a molecular foundation for the mechanisms by which PVM efficiently subverts the IFN response of the murine cell. They also reveal that in spite of their high sequence dissimilarity, the two pneumoviral NS proteins are functionally and mechanistically similar.

  7. Coformer selection based on degradation pathway of drugs: a case study of adefovir dipivoxil-saccharin and adefovir dipivoxil-nicotinamide cocrystals.

    Science.gov (United States)

    Gao, Yuan; Gao, Jing; Liu, Ziling; Kan, Hongliang; Zu, Hui; Sun, Wanjin; Zhang, Jianjun; Qian, Shuai

    2012-11-15

    Adefovir dipivoxil (AD) is a bis(pivaloyloxymethyl) prodrug of adefovir with chemical stability problem. It undergoes two degradation pathways including hydrolysis and dimerization during storage. Pharmaceutical cocrystallization exhibits a promising approach to enhance aqueous solubility as well as physicochemical stability. In this study we attempted to prepare and investigate the physiochemical properties of AD cocrystals, which were formed with two coformers having different acidity and alkalinity (weakly acidic saccharin (SAC) and weakly basic nicotinamide (NCT)). The presence of different coformer molecules along with AD resulted in altered physicochemical properties. AD-SAC cocrystal showed great improvement in solubility and chemical stability, while AD-NCT did not. Several potential factors giving rise to different solid-state properties were summarized. Different coformers resulted in different cocrystal formation, packing style and hydrogen bond formation. This study could provide the coformer selection strategy based on degradation pathways for some unstable drugs in pharmaceutical cocrystal design. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Formation and degradation pathways of intermediate products formed during the hydropyrolysis of glucose as a model substance for wet biomass in a tubular reactor

    Energy Technology Data Exchange (ETDEWEB)

    Sinag, A. [Department of Chemistry, Science Faculty, Ankara University, 06100 Besevler-Ankara (Turkey); Kruse, A.; Schwarzkopf, V. [Institut fuer Technische Chemie - CPV, Forschungszentrum Karlsruhe GmbH, P.O. Box 3640, D-76021 Karlsruhe (Germany)

    2003-12-10

    In this study, glucose as a model substance for cellulose is pyrolyzed in supercritical water. The experiments are conducted in a continuously operated tubular reactor. From the usage of model substances, key information on the degradation pathway of biomass in supercritical water can be obtained. With this knowledge, it is tried to optimize a new method for gasification of wet biomass considering high yields of hydrogen and methane and also the suppressing of tar and char formation. The gaseous products mainly contain hydrogen, carbon dioxide, methane and a small amount of carbon monoxide. The effect of experimental conditions, such as pressure, temperature and reaction time, on the degradation of glucose is investigated in the experiments. The qualitative and quantitative composition of the gas and liquid phases formed are determined. The results show that only the amount of phenols increases with increasing temperature in the liquid phase. No complete gasification of glucose is achieved in the studied temperature range between 400 C and 500 C. The addition of alkali salts leads to a higher gas generation and to a decrease in carbon monoxide concentration via water-gas-shift reaction. A lower furfural concentration is obtained in the presence of KHCO{sub 3}. Furthermore, this study shows that there is a wide conformity between the results of real and model biomass. A simplified scheme for glucose degradation is also presented with the help of the results found. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  9. 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

  10. 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.

  11. 21 CFR 109.30 - Tolerances for polychlorinated biphenyls (PCB's).

    Science.gov (United States)

    2010-04-01

    ... Tolerances for polychlorinated biphenyls (PCB's). (a) Polychlorinated biphenyls (PCB's) are toxic, industrial chemicals. Because of their widespread, uncontrolled industrial applications, PCB's have become a persistent... unavoidable environmental or industrial contaminants are established for a sufficient period of time following...

  12. 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

  13. Phytoremediation of Polychlorinated Biphenyls: New Trends and Promises

    Science.gov (United States)

    Van Aken, Benoit; Correa, Paola A.; Schnoor, Jerald L.

    2011-01-01

    Transgenic plants and associated bacteria constitute a new generation of genetically modified organisms for efficient and environmental-friendly treatment of soil and water contaminated with polychlorinated biphenyls (PCBs). This review focuses on recent advances in phytoremediation for the treatment of PCBs, including the development of transgenic plants and associated bacteria. Phytoremediation, or the use of higher plants for rehabilitation of soil and groundwater, is a promising strategy for cost-effective treatment of sites contaminated by toxic compounds, including toxic PCBs. Plants can help mitigate environmental pollution by PCBs through a range of mechanisms: besides uptake from soil (phytoextraction), plants are capable of enzymatic transformation of PCBs (phytotransformation); by releasing a variety of secondary metabolites, plants also enhance the microbial activity in the root zone, improving biodegradation of PCBs (rhizoremediation). However, because of their hydrophobicity and chemical stability, PCBs are only slowly taken up and degraded by plants and associated bacteria, resulting in incomplete treatment and potential release of toxic metabolites into the environment. Moreover, naturally occurring plant-associated bacteria may not possess the enzymatic machinery necessary for PCB degradation. In order to overcome these limitations, bacterial genes involved in the metabolism of PCBs, such as biphenyl dioxygenases, have been introduced into higher plants, following a strategy similar to the development of transgenic crops. Similarly, bacteria have then been genetically modified that exhibit improved biodegradation capabilities and are able to maintain stable relationships with plants. Transgenic plants and associated bacteria bring hope for a broader and more efficient application of phytoremediation for the treatment of PCBs. PMID:20384372

  14. 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.

  15. Downregulation of miR-221-3p contributes to IL-1β-induced cartilage degradation by directly targeting the SDF1/CXCR4 signaling pathway.

    Science.gov (United States)

    Zheng, Xin; Zhao, Feng-Chao; Pang, Yong; Li, Dong-Ya; Yao, Sheng-Cheng; Sun, Shao-Song; Guo, Kai-Jin

    2017-06-01

    Osteoarthritis (OA) is characterized by degradation of chondrocyte extracellular matrix (ECM). Accumulating evidence suggests that microRNAs (miRNAs) are associated with OA, but little is known of their function in chondrocyte ECM degradation. The objective of this study was to investigate the expression and function of miRNAs in OA. miRNA expression profile was determined in OA cartilage tissues and controls, employing Solexa sequencing and reverse transcription quantitative PCR (RT-qPCR). According to a modified Mankin scale, cartilage degradation was evaluated. Functional analysis of the miRNAs on chondrocyte ECM degradation was performed after miRNA transfection and IL-1β treatment. Luciferase reporter assays and western blotting were employed to determine miRNA targets. Expression of miR-221-3p was downregulated in OA cartilage tissues, which was significantly correlated with a modified Mankin scale. Through gain-of-function and loss-of-function studies, miR-221-3p was shown to significantly affect matrix synthesis gene expression and chondrocyte proliferation and apoptosis. Using SW1353 and C28I2 cells, SDF1 was identified as a target of miR-221-3p. SDF1 overexpression resulted in increased expression of catabolic genes such as MMP-13 and ADAMTS-5 in response to IL-1β, but these effects were moderated by miR-221-3p. SDF1 treatment antagonized this effect, while knockdown of SDF1 by shSDF1 induced inhibitory effects on the expression of CXCR4 and its main target genes, similar to miR-221-3p. The results indicate that upregulation of miR-221-3p could prevent IL-1β-induced ECM degradation in chondrocytes. Targeting the SDF1/CXCR4 signaling pathway may be used as a therapeutic approach for OA. miR-221-3p is downregulated in human cartilage tissues. miR-221-3p levels are associated with cartilage degeneration grade. miR-221-3p upregulation prevents IL-1β-induced ECM degradation in chondrocytes. Protection of ECM degradation by miR-223-3p occurs via SDF1/CXCR4

  16. Skp2 regulates androgen receptor through ubiquitin-mediated degradation independent of Akt/mTOR pathways in prostate cancer.

    Science.gov (United States)

    Li, Bo; Lu, Wenfu; Yang, Qing; Yu, Xiuping; Matusik, Robert J; Chen, Zhenbang

    2014-04-01

    The intervention of advanced prostate cancer (PCa) in patients has been commonly depending on androgen deprivation therapy. Despite of tremendous research efforts, however, molecular mechanisms on AR regulation remain poorly understood, particularly for castration resistant prostate cancer (CRPC). Targeting AR and associated factors is considered an effective strategy in PCa treatment. Human prostate cancer cells were used in this study. Manipulations of Skp2 expression were achieved by Skp2 shRNA/siRNA or overexpression of plasmids. Dual luciferase reporter assay was applied for AR activity assessment. Western blot, ubiquitination assay, immunoprecipitation, and immunofluorescence were applied to detect the proteins. Our results demonstrated that Skp2 directly involves the regulation of AR expression through ubiquitination-mediated degradation. Skp2 interacted with AR protein in PCa cells, and enforced expression of Skp2 resulted in a decreased level and activity of AR. By contrast, Skp2 knockdown increased the protein accumulation and activity of AR. Importantly, changes of AR contributed by Skp2 led to subsequent alterations of PSA level in PCa cells. AR ubiquitination was significantly increased upon Skp2 overexpression but greatly reduced upon Skp2 knockdown. AR mutant at K847R abrogated Skp2-mediated ubiquitination of AR. NVP-BEZ235, a dual PI3K/mTOR inhibitor, remarkably inhibited Skp2 level with a striking elevation of AR. The results indicate that Skp2 is an E3 ligase for proteasome-dependent AR degradation, and K847 on AR is the recognition site for Skp2-mediated ubiquitination. Our findings reveal an essential role of Skp2 in AR signaling. © 2013 Wiley Periodicals, Inc.

  17. 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)

  18. 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.

  19. 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

    International Nuclear Information System (INIS)

    Ahuactzin-Pérez, Miriam; Tlecuitl-Beristain, Saúl; García-Dávila, Jorge; González-Pérez, Manuel; Gutiérrez-Ruíz, María Concepción; Sánchez, Carmen

    2016-01-01

    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_m_a_x), biodegradation constant of DEHP (k), half-life (t_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_m_a_x 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_1_/_2 were 0.024 h"−"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.

  20. 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.

  1. 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

  2. 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

  3. 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

  4. 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.

  5. How early studies on secreted and membrane protein quality control gave rise to the ER associated degradation (ERAD) pathway: the early history of ERAD.

    Science.gov (United States)

    Needham, Patrick G; Brodsky, Jeffrey L

    2013-11-01

    All newly synthesized proteins are subject to quality control check-points, which prevent aberrant polypeptides from harming the cell. For proteins that ultimately reside in the cytoplasm, components that also reside in the cytoplasm were known for many years to mediate quality control. Early biochemical and genetic data indicated that misfolded proteins were selected by molecular chaperones and then targeted to the proteasome (in eukaryotes) or to proteasome-like particles (in bacteria) for degradation. What was less clear was how secreted and integral membrane proteins, which in eukaryotes enter the endoplasmic reticulum (ER), were subject to quality control decisions. In this review, we highlight early studies that ultimately led to the discovery that secreted and integral membrane proteins also utilize several components that constitute the cytoplasmic quality control machinery. This component of the cellular quality control pathway is known as ER associated degradation, or ERAD. This article is part of a Special Issue entitled: Functional and structural diversity of endoplasmic reticulum. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. 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.

  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. Transport and degradation of dissolved organic matter and associated freshwater pathways in the Laptev Sea (Siberian Arctic)

    Science.gov (United States)

    Hoelemann, Jens; Janout, Markus; Koch, Boris; Bauch, Dorothea; Hellmann, Sebastian; Eulenburg, Antje; Heim, Birgit; Kassens, Heidemarie; Timokhov, leonid

    2016-04-01

    The Siberian shelves are seasonally ice-covered and characterized by large freshwater runoff rates from some of the largest rivers on earth. These rivers also provide a considerable amount of dissolved organic carbon (DOC) to the Arctic Ocean. With an annual load of about 6 Tg DOC a-1 the Lena River contributes nearly 20 percent of the annual DOC discharge to the Arctic Ocean. We present a comprehensive dataset collected during multiple Laptev Sea expeditions carried out in spring, summer and fall (2010-15) in order to explore the processes controlling the dispersal and degradation of DOM during the river water's passage across the shelf. Our investigations are focused on CDOM (Colored Dissolved Organic Matter), which resembles the DOC concentration, interacts with solar radiation and forms a major fraction of the organic matter pool. Our results show an inverse correlation between salinity and CDOM, which emphasizes its terrigenous source. Further, the spectral slope of CDOM absorption indicates that photochemical bleaching is the main process that reduces the CDOM absorption (~ 20%) in freshwater along its transport across the shelf. The distribution of the Lena river water is primarily controlled by winds in summer. During summers with easterly or southerly winds, the plume remains on the central and northern Laptev shelf, and is available for export into the Arctic Basin. The CDOM-rich river water increases the absorption of solar radiation and enhances warming of a shallow surface layer. This emphasizes the importance of CDOM for sea surface temperatures and lateral ice melt on the shelf and adjacent basin. DOC concentrations in freshwater vary seasonally and become larger with increasing discharge. Our data indicate that the CDOM concentrations are highest during the freshet when landfast ice is still present. Subsequent mixing with local sea ice meltwater lowers CDOM to values that are characteristic for the Lena freshwater during the rest of the year.

  9. A model for the catabolism of rhizopine in Rhizobium leguminosarum involves a ferredoxin oxygenase complex and the inositol degradative pathway.

    Science.gov (United States)

    Bahar, M; de Majnik, J; Wexler, M; Fry, J; Poole, P S; Murphy, P J

    1998-11-01

    Rhizopines are nodule-specific compounds that confer an intraspecies competitive nodulation advantage to strains that can catabolize them. The rhizopine (3-O-methyl-scyllo-inosamine, 3-O-MSI) catabolic moc gene cluster mocCABRDE(F) in Rhizobium leguminosarum bv. viciae strain 1a is located on the Sym plasmid. MocCABR are homologous to the mocCABR gene products from Sinorhizobium meliloti. MocD and MocE contain motifs corresponding to a TOL-like oxygenase and a [2Fe-2S] Rieske-like ferredoxin, respectively. The mocF gene encodes a ferredoxin reductase that would complete the oxygenase system, but is not essential for rhizopine catabolism. We propose a rhizopine catabolic model whereby MocB transports rhizopine into the cell and MocDE and MocF (or a similar protein elsewhere in the genome), under the regulation of MocR, act in concert to form a ferredoxin oxygenase system that demethylates 3-O-MSI to form scyllo-inosamine (SI). MocA, an NAD(H)-dependent dehydrogenase, and MocC continue the catabolic process. Compounds formed then enter the inositol catabolic pathway.

  10. 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...

  11. Characterization of 3-ketosteroid 9{alpha}-hydroxylase, a Rieske oxygenase in the cholesterol degradation pathway of Mycobacterium tuberculosis.

    Science.gov (United States)

    Capyk, Jenna K; D'Angelo, Igor; Strynadka, Natalie C; Eltis, Lindsay D

    2009-04-10

    KshAB (3-Ketosteroid 9alpha-hydroxylase) is a two-component Rieske oxygenase (RO) in the cholesterol catabolic pathway of Mycobacterium tuberculosis. Although the enzyme has been implicated in pathogenesis, it has largely been characterized by bioinformatics and molecular genetics. Purified KshB, the reductase component, was a monomeric protein containing a plant-type [2Fe-2S] cluster and FAD. KshA, the oxygenase, was a homotrimer containing a Rieske [2Fe-2S] cluster and mononuclear ferrous iron. Of two potential substrates, reconstituted KshAB had twice the specificity for 1,4-androstadiene-3,17-dione as for 4-androstene-3,17-dione. The transformation of both substrates was well coupled to the consumption of O(2). Nevertheless, the reactivity of KshAB with O(2) was low in the presence of 1,4-androstadiene-3,17-dione, with a k(cat)/K(m)(O(2)) of 2450 +/- 80 m(-1) s(-1). The crystallographic structure of KshA, determined to 2.3A(,) revealed an overall fold and a head-to-tail subunit arrangement typical of ROs. The central fold of the catalytic domain lacks all insertions found in characterized ROs, consistent with a minimal and perhaps archetypical RO catalytic domain. The structure of KshA is further distinguished by a C-terminal helix, which stabilizes subunit interactions in the functional trimer. Finally, the substrate-binding pocket extends farther into KshA than in other ROs, consistent with the large steroid substrate, and the funnel accessing the active site is differently orientated. This study provides a solid basis for further studies of a key steroid-transforming enzyme of biotechnological and medical importance.

  12. Molecular mechanism and genetic determinants of buprofezin degradation.

    Science.gov (United States)

    Chen, Xueting; Ji, Junbin; Zhao, Leizhen; Qiu, Jiguo; Dai, Chen; Wang, Weiwu; He, Jian; Jiang, Jiandong; Hong, Qing; Yan, Xin

    2017-07-14

    Buprofezin is a widely used insect growth regulator whose residue has been frequently detected in the environment, posing a threat to aquatic organisms and non-target insects. Microorganisms play an important role in the degradation of buprofezin in the natural environment. However, the relevant catabolic pathway has not been fully characterized, and the molecular mechanism of catabolism is still completely unknown. Rhodococcus qingshengii YL-1 can utilize buprofezin as a sole source of carbon and energy for growth. In this study, the upstream catabolic pathway in strain YL-1 was identified using tandem mass spectrometry. Buprofezin is composed of a benzene ring and a heterocyclic ring. The degradation is initiated by the dihydroxylation of the benzene ring and continues via dehydrogenation, aromatic ring cleavage, breaking of an amide bond and the release of the heterocyclic ring 2- tert -butylimino-3-isopropyl-1,3,5-thiadiazinan-4-one (2-BI). A buprofezin degradation-deficient mutant strain YL-0 was isolated. Comparative genomic analysis combined with gene deletion and complementation experiments revealed that the gene cluster bfzBA3A4A1A2C is responsible for the upstream catabolic pathway of buprofezin. bfzA3A4A1A2 encodes a novel Rieske non-heme iron oxygenase (RHO) system that is responsible for the dihydroxylation of buprofezin at the benzene ring; bfzB is involved in dehydrogenation, and bfzC is in charge of benzene ring cleavage. Furthermore, the products of bfzBA3A4A1A2C can also catalyze dihydroxylation, dehydrogenation and aromatic ring cleavage of biphenyl, flavanone, flavone and bifenthrin. In addition, a transcriptional study revealed that bfzBA3A4A1A2C is organized in one transcriptional unit that is constitutively expressed in strain YL-1. Importance There is an increasing concern about the residue and environmental fate of buprofezin. Microbial metabolism is an important mechanism responsible for the buprofezin degradation in natural environment

  13. Polychlorinated biphenyls and their interaction with the environment

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-05-01

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

  14. 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.

  15. Oxidation of Tris (2-chloroethyl) phosphate in aqueous solution by UV-activated peroxymonosulfate: Kinetics, water matrix effects, degradation products and reaction pathways.

    Science.gov (United States)

    Xu, Xinxin; Chen, Jing; Qu, Ruijuan; Wang, Zunyao

    2017-10-01

    The feasibility of UV-activated peroxymonosulfate (PMS) technology for the degradation of Tris (2-chloroethyl) phosphate (TCEP) in an aqueous solution was investigated in this study. The conditions of [PMS] 0 : [TCEP] 0  = 20:1, T = 25 ± 2 °C and pH = 5.5 ± 0.5 cause a 94.6% removal of TCEP (1 mg L -1 ) after 30 min of Hg lamp irradiation. The effects of operating parameters (the oxidant doses, pH and presence of typical cations (Fe 3+ , Cu 2+ , Ni 2+ , NH 4 + ), anions (Cl - , HCO 3 - , NO 3 - , HPO 4 2- ) and humic acid (HA)) were evaluated. It was found that an increase of the PMS dose and the presence of Fe 3+ could accelerate the reaction, while the anions and HA inhibited the reaction. Meanwhile, TCEP removal in various water matrices was compared, and the order for TCEP removal was as follows: ultrapure water > tap water > synthetic water > secondary clarifier effluent > Jiuxiang river water. Twenty-two oxidation products were identified using an electrospray time-of-flight mass spectrometer, and the degradation pathways mainly involved radicals' addition and CO bond cleavage. Furthermore, ECOSAR analysis revealed that the intermediate products during the TCEP oxidation process were generally not harmful to three typical aquatic species. Hence, UV/PMS can be used as an efficient technology to treat TCEP-containing water and wastewaters. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

    Wang, A-nan [Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); Teng, Ying [Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Hu, Xue-feng [Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China); Wu, Long-hua; Huang, Yu-juan [Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Luo, Yong-ming, E-mail: ymluo@yic.ac.cn [Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China); Christie, Peter [Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China)

    2016-01-15

    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{sub 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{sub 9}(3){sup 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{sub 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{sup −1} were found to be a 1:10 soil: water ratio, 40 mW cm{sup −2} light intensity, 5% TiO{sub 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{sub 2} in soil slurry. This study suggests that TiO{sub 2} photocatalytic oxidation is a promising treatment for removing DPAA from soil. - Highlights: • DPAA was degraded into arsenate through TiO{sub 2} (P25) photocatalytic oxidation. • Soil/water ratio was more influential on the removal of DPAA in soil by TiO{sub 2} (P25). • Soil properties affected the adsorption of DPAA and the generation of OH• by Ti

  17. 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.

  18. 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...

  19. Enrichment and Characterization of PCB-Degrading Bacteria as Potential Seed Cultures for Bioremediation of Contaminated Soil

    Directory of Open Access Journals (Sweden)

    Dubravka Hršak

    2007-01-01

    Full Text Available The main objective of our study was to obtain seed cultures for enhancing the transformation of polychlorinated biphenyls (PCBs in contaminated soil of the transformer station in Zadar, Croatia, damaged during warfare activities in 1991. For enrichment, six soil samples were collected from different polluted areas and microcosm approach, stimulating the growth of biphenyl-degrading bacteria, was employed. Enrichment experiments resulted in the selection of two fast growing mixed cultures TSZ7 and AIR1, originating from the soil of the transformer station and the airport area, respectively. Both cultures showed significant PCB-degrading activity (56 to 60 % of PCB50 mixture was reduced after a two-week cultivation. Furthermore, the cultures displayed similar PCB-degrading competence and reduced di-to tetrachlorobiphenyls more effectively than penta- to hepta-chlorobiphenyls. Strain Z6, identified as Rhodococcus erythropolis, was found to be the only culture member showing PCB-transformation potential similar to that of the mixed culture TSZ7, from which it was isolated. Based on the metabolites identified in the assay with the single congener 2,4,4’-chlorobiphenyl, we proposed that the strain Z6 was able to use both the 2,3-and 3,4-dioxygenase pathways. Furthermore, the identified metabolites suggested that beside these pathways another unidentified pathway might also be active in strain Z6. Based on the obtained results, the culture TSZ7 and the strain Z6 were designated as potential seed cultures for bioremediation of the contaminated soil.

  20. Isolation of the phe-operon from G. stearothermophilus comprising the phenol degradative meta-pathway genes and a novel transcriptional regulator

    Directory of Open Access Journals (Sweden)

    Reiss Monika

    2008-11-01

    Full Text Available Abstract Background Geobacillus stearothermophilus is able to utilize phenol as a sole carbon source. A DNA fragment encoding a phenol hydroxylase catalyzing the first step in the meta-pathway has been isolated previously. Based on these findings a PCR-based DNA walk was performed initially to isolate a catechol 2,3-dioxygenase for biosensoric applications but was continued to elucidate the organisation of the genes encoding the proteins for the metabolization of phenol. Results A 20.2 kb DNA fragment was isolated as a result of the DNA walk. Fifteen open reading frames residing on a low-copy megaplasmid were identified. Eleven genes are co-transcribed in one polycistronic mRNA as shown by reverse transcription-PCR. Ten genes encode proteins, that are directly linked with the meta-cleavage pathway. The deduced amino acid sequences display similarities to a two-component phenol hydroxylase, a catechol 2,3-dioxygenase, a 4-oxalocrotonate tautomerase, a 2-oxopent-4-dienoate hydratase, a 4-oxalocrotonate decarboxylase, a 4-hydroxy-2-oxovalerate aldolase, an acetaldehyde dehydrogenase, a plant-type ferredoxin involved in the reactivation of extradiol dioxygenases and a novel regulatory protein. The only enzymes missing for the complete mineralization of phenol are a 2-hydroxymuconic acid-6-semialdehyde hydrolase and/or 2-hydroxymuconic acid-6-semialdehyde dehydrogenase. Conclusion Research on the bacterial degradation of aromatic compounds on a sub-cellular level has been more intensively studied in gram-negative organisms than in gram-positive bacteria. Especially regulatory mechanisms in gram-positive (thermophilic prokaryotes remain mostly unknown. We isolated the first complete sequence of an operon from a thermophilic bacterium encoding the meta-pathway genes and analyzed the genetic organization. Moreover, the first transcriptional regulator of the phenol metabolism in gram-positive bacteria was identified. This is a first step to elucidate

  1. Salubrinal Suppresses IL-17-Induced Upregulation of MMP-13 and Extracellular Matrix Degradation Through the NF-kB Pathway in Human Nucleus Pulposus Cells.

    Science.gov (United States)

    Yao, Zhixiao; Nie, Lin; Zhao, Yunpeng; Zhang, Yuanqiang; Liu, Yi; Li, Jingkun; Cheng, Lei

    2016-12-01

    Matrix metalloproteinase 13 (MMP-13) plays an important role in the process of pro-inflammatory cytokine-induced intervertebral disc degeneration (IDD). This study examined the effect of IL-17 on the regulation of MMP-13 and the extracellular matrix (ECM) in the intervertebral disc (IVD). We then examined whether salubrinal, a known inhibitor of eIF2α dephosphorylation, inhibited the IL-17-induced changes mentioned above. Furthermore, we demonstrated a potential therapeutic role for salubrinal in alleviating the chronic inflammatory-dependent degenerative state commonly observed in IDD. After inflammatory distress with IL-17, RT-PCR and western blot were employed to investigate the expression of MMP-13, collagen type II (COL2A1), collagen type I (COL1A1), and aggrecan (ACAN) in nucleus pulpous (NP) tissue. Activation of the NF-kB pathway was measured by western blot and immunocytochemistry following IL-17 treatment. We also examine the level of eIF2α phosphorylation after IL-17 treatment with or without salubrinal. Then, we investigated interactions of the NF-kB pathway to eIF2α phosphorylation. Moreover, we employed salubrinal and a specific inhibitor of NF-kB (BAY11-7082) to evaluate their effects on IL-17-driven regulation of MMP-13 and the ECM, as well as on the activation of NF-kB. The results showed that IL-17 increased the production of MMP-13 and decreased expression of COL2A1 and ACAN via the NF-kB pathway. Either IL-17 or salubrinal increased the level of eIF2α phosphorylation, but the effects of BAY11-7082 on the level of p-eIF2α were not detectable. BAY11-7082 and salubrinal significantly suppressed IL-17-driven intervertebral disc degeneration. Furthermore, salubrinal produced stronger effects than BAY11-7082. These results imply the potential involvement of IL-17 in IDD through activation of NF-kB signaling, which successively upregulated the expression of MMP-13 and led to the degradation of the ECM. Furthermore, salubrinal can inhibit this

  2. 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.

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

    Science.gov (United States)

    Li, Huiyuan; Li, Yanli; Xiang, Luojing; Huang, Qianqian; Qiu, Juanjuan; Zhang, Hui; Sivaiah, Matte Venkata; Baron, Fabien; Barrault, Joel; Petit, Sabine; Valange, Sabine

    2015-04-28

    A ferric smectite clay material was synthesized and further intercalated with Al2O3 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 0.5g/L and hydrogen peroxide concentration of 13.5mM 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 160mg/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 150min reaction, indicating that the effluent was suitable for sequential biological treatment. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. 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; Hong, Miao; Falivene, Laura; Caporaso, Lucia; Cavallo, Luigi; Chen, Eugene Y X

    2016-01-01

    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.

  5. Metabolism of chlorobiphenyls by a variant biphenyl dioxygenase exhibiting enhanced activity toward dibenzofuran

    International Nuclear Information System (INIS)

    Viger, Jean-François; Mohammadi, Mahmood; Barriault, Diane; Sylvestre, Michel

    2012-01-01

    Highlights: ► Burkholderia xenovorans LB400 biphenyl dioxygenase (BphAE LB400 ) metabolizes PCBs. ► Asn338Gln/Leu409Phe double mutation speeds up electron transfer of enzyme reaction. ► We tested how the mutations affect the PCB-degrading abilities of BphAE LB400 variants. ► The same mutations also broaden the PCB substrate range of BphAE LB400 variants. -- Abstract: The biphenyl dioxygenase of Burkholderia xenovorans LB400 (BphAE LB400 ) catalyzes the dihydroxylation of biphenyl and of several polychlorinated biphenyls (PCBs) but it poorly oxidizes dibenzofuran. In this work we showed that BphAE RR41 , a variant which was previously found to metabolize dibenzofuran more efficiently than its parent BphAE LB400 , metabolized a broader range of PCBs than BphAE LB400 . Hence, BphAE RR41 was able to metabolize 2,6,2′,6′-, 3,4,3′,5′- and 2,4,3′,4′-tetrachlorobiphenyl that BphAE LB400 is unable to metabolize. BphAE RR41 was obtained by changing Thr335Phe336Asn338Ile341Leu409 of BphAE LB400 to Ala335Met336Gln338Val341Phe409. Site-directed mutagenesis was used to create combinations of each substitution, in order to assess their individual contributions. Data show that the same Asn338Glu/Leu409Phe substitution that enhanced the ability to metabolize dibenzofuran resulted in a broadening of the PCB substrates range of the enzyme. The role of these substitutions on regiospecificities toward selected PCBs is also discussed.

  6. Metabolism of chlorobiphenyls by a variant biphenyl dioxygenase exhibiting enhanced activity toward dibenzofuran

    Energy Technology Data Exchange (ETDEWEB)

    Viger, Jean-Francois; Mohammadi, Mahmood; Barriault, Diane [Institut National de la Recherche Scientifique, INRS-Institut Armand-Frappier, Laval, Quebec, Canada H4K 1C2 (Canada); Sylvestre, Michel, E-mail: Michel.Sylvestre@iaf.inrs.ca [Institut National de la Recherche Scientifique, INRS-Institut Armand-Frappier, Laval, Quebec, Canada H4K 1C2 (Canada)

    2012-03-09

    Highlights: Black-Right-Pointing-Pointer Burkholderia xenovorans LB400 biphenyl dioxygenase (BphAE{sub LB400}) metabolizes PCBs. Black-Right-Pointing-Pointer Asn338Gln/Leu409Phe double mutation speeds up electron transfer of enzyme reaction. Black-Right-Pointing-Pointer We tested how the mutations affect the PCB-degrading abilities of BphAE{sub LB400} variants. Black-Right-Pointing-Pointer The same mutations also broaden the PCB substrate range of BphAE{sub LB400} variants. -- Abstract: The biphenyl dioxygenase of Burkholderia xenovorans LB400 (BphAE{sub LB400}) catalyzes the dihydroxylation of biphenyl and of several polychlorinated biphenyls (PCBs) but it poorly oxidizes dibenzofuran. In this work we showed that BphAE{sub RR41}, a variant which was previously found to metabolize dibenzofuran more efficiently than its parent BphAE{sub LB400}, metabolized a broader range of PCBs than BphAE{sub LB400}. Hence, BphAE{sub RR41} was able to metabolize 2,6,2 Prime ,6 Prime -, 3,4,3 Prime ,5 Prime - and 2,4,3 Prime ,4 Prime -tetrachlorobiphenyl that BphAE{sub LB400} is unable to metabolize. BphAE{sub RR41} was obtained by changing Thr335Phe336Asn338Ile341Leu409 of BphAE{sub LB400} to Ala335Met336Gln338Val341Phe409. Site-directed mutagenesis was used to create combinations of each substitution, in order to assess their individual contributions. Data show that the same Asn338Glu/Leu409Phe substitution that enhanced the ability to metabolize dibenzofuran resulted in a broadening of the PCB substrates range of the enzyme. The role of these substitutions on regiospecificities toward selected PCBs is also discussed.

  7. Degradative pathways for p-toluenecarboxylate and p-toluenesulfonate and their multicomponent oxygenases in Comamonas testosteroni strains PSB-4 and T-2.

    Science.gov (United States)

    Junker, F; Saller, E; Schläfli Oppenberg, H R; Kroneck, P M; Leisinger, T; Cook, A M

    1996-09-01

    Three multicomponent oxygenases involved in the degradation of p-toluenesulfonate and p-toluenecarboxylate and the regulation of their synthesis have been examined in three strains (T-2, PSB-4 and TER-1) of Comamonas testosteroni. Strain T-2 utilizes p-toluenesulfonate as a source of carbon and energy for growth via p-sulfobenzoate and protocatechuate, and p-toluenecarboxylate via terephthalate and protocatechuate, and has the unusual property of requiring the reductase (TsaB) of the toluenesulfonate methyl monooxygenase system (TsaMB) in an incompletely expressed sulfobenzoate dioxygenase system (PsbAC) [Schläfli Oppenberg, H.R., Chen, G., Leisinger, T. & Cook, A. M. (1995). Microbiology 141, 1891-1899]. The independently isolated C. testosteroni PSB-4 utilized only sulfobenzoate and terephthalate via protocatechuate. Mutant TER-1, derived from strain T-2, utilized only terephthalate via protocatechuate. We detected no enzymes of the pathway from toluenesulfonate to sulfobenzoate in strains PSB-4 and TER-1, and confirmed by PCR and Southern blot analysis that the genes (tsaMB) encoding toluenesulfonate monooxygenase were absent. We concluded that, in strain PSB-4, the regulatory unit encoding the genes for the conversion of toluenesulfonate to sulfobenzoate was missing, and that generation of mutant TER-1 involved deletion of this regulatory unit and of the regulatory unit encoding desulfonation of sulfobenzoate. The degradation of sulfobenzoate in strain PSB-4 was catalysed by a fully inducible sulfobenzoate dioxygenase system (PsbACPSB-4), which, after purification of the oxygenase component (PsbAPSB-4), turned out to be indistinguishable from the corresponding component from strain T-2 (PsbAT-2). Reductase PsbCPSB-4, which we could separate but not purify, was active with oxygenase PsbAPSB-4 and PsbAT-2. Oxygenase PsbAPSB-4 was shown by electron paramagnetic resonance spectroscopy to contain a Rieske [2Fe-2S] centre. The enzyme system oxygenating terephthalate

  8. Efficient degradation of TCE in groundwater using Pd and electro-generated H2 and O2: a shift in pathway from hydrodechlorination to oxidation in the presence of ferrous ions.

    Science.gov (United States)

    Yuan, Songhu; Mao, Xuhui; Alshawabkeh, Akram N

    2012-03-20

    Degradation of trichloroethylene (TCE) in simulated groundwater by Pd and electro-generated H(2) and O(2) is investigated in the absence and presence of Fe(II). In the absence of Fe(II), hydrodechlorination dominates TCE degradation, with accumulation of H(2)O(2) up to 17 mg/L. Under weak acidity, low concentrations of oxidizing •OH radicals are detected due to decomposition of H(2)O(2), slightly contributing to TCE degradation via oxidation. In the presence of Fe(II), the degradation efficiency of TCE at 396 μM improves to 94.9% within 80 min. The product distribution proves that the degradation pathway shifts from 79% hydrodechlorination in the absence of Fe(II) to 84% •OH oxidation in the presence of Fe(II). TCE degradation follows zeroth-order kinetics with rate constants increasing from 2.0 to 4.6 μM/min with increasing initial Fe(II) concentration from 0 to 27.3 mg/L at pH 4. A good correlation between TCE degradation rate constants and •OH generation rate constants confirms that •OH is the predominant reactive species for TCE oxidation. Presence of 10 mM Na(2)SO(4), NaCl, NaNO(3), NaHCO(3), K(2)SO(4), CaSO(4), and MgSO(4) does not significantly influence degradation, but sulfite and sulfide greatly enhance and slightly suppress degradation, respectively. A novel Pd-based electrochemical process is proposed for groundwater remediation.

  9. 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.

  10. 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...

  11. Process for removing polychlorinated biphenyls from soil

    Science.gov (United States)

    Hancher, C.W.; Saunders, M.B.; Googin, J.M.

    1984-11-16

    The present invention relates to a method of removing polychlorinated biphenyls from soil. The polychlorinated biphenyls are extracted from the soil by employing a liquid organic solvent dispersed in water in the ratio of about 1:3 to 3:1. The organic solvent includes such materials as short-chain hydrocarbons including kerosene or gasoline which are immiscible with water and are nonpolar. The organic solvent has a greater affinity for the PCB's than the soil so as to extract the PCB's from the soil upon contact. The organic solvent phase is separated from the suspended soil and water phase and distilled for permitting the recycle of the organic solvent phase and the concentration of the PCB's in the remaining organic phase. The present process can be satisfactorily practiced with soil containing 10 to 20% petroleum-based oils and organic fluids such as used in transformers and cutting fluids, coolants and the like which contain PCB's. The subject method provides for the removal of a sufficient concentration of PCB's from the soil to provide the soil with a level of PCB's within the guidelines of the Environmental Protection Agency.

  12. Kinetic study of photocatalytic degradation of carbamazepine, clofibric acid, iomeprol and iopromide assisted by different TiO2 materials--determination of intermediates and reaction pathways.

    Science.gov (United States)

    Doll, Tusnelda E; Frimmel, Fritz H

    2004-02-01

    The light-induced degradation of clofibric acid, carbamazepine, iomeprol and iopromide under simulated solar irradiation has been investigated in aqueous solutions suspended with different TiO2 materials (P25 and Hombikat UV100). Kinetic studies showed that P25 had a better photocatalytic activity for clofibric acid and carbamazepine than Hombikat UV100. For photocatalytic degradation of iomeprol Hombikat UV100 was more suitable than P25. The results can be explained by the higher adsorption capacity of Hombikat UV100 for iomeprol. The study also focuses on the identification and quantification of possible degradation products. The degradation process was monitored by determination of sum parameters and inorganic ions. In case of clofibric acid various aromatic and aliphatic degradation products have been identified and quantified. A possible multi-step degradation scheme for clofibric acid is proposed. This study proves the high potential of the photocatalytic oxidation process to transform and mineralize environmentally relevant pharmaceuticals and contrast media in water.

  13. 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.

  14. Chemical conversion pathways and kinetic modeling for the OH-initiated reaction of triclosan in gas-phase.

    Science.gov (United States)

    Zhang, Xue; Zhang, Chenxi; Sun, Xiaomin; Kang, Lingyan; Zhao, Yan

    2015-04-10

    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 k add/k total and k abs/k total 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.

  15. TOF-SIMS investigation of degradation pathways occurring in a variety of organic photovoltaic devices – the ISOS-3 inter-laboratory collaboration

    DEFF Research Database (Denmark)

    Andreasen, Birgitta; Tanenbaum, David; Hermenau, Martin

    2012-01-01

    -depth in the organic solar cells. Various degradation mechanisms were investigated and correlated with cell performance. For example, photo-oxidation of the active material was quantitatively studied as a function of cell performance. The large variety of cell architectures used (some with and some without......-destructive and destructive techniques in order to identify specific degradation mechanisms responsible for the deterioration of the photovoltaic response. Work presented herein involves time-of-flight secondary ion mass spectrometry (TOF-SIMS) in order to study chemical degradation in-plane as well as in...... of organic solar cells....

  16. 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...

  17. 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...

  18. 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...

  19. Decolorization of complex dyes and textile effluent by extracellular enzymes of Cyathus bulleri cultivated on agro-residues/domestic wastes and proposed pathway of degradation of Kiton blue A and reactive orange 16.

    Science.gov (United States)

    Vats, Arpita; Mishra, Saroj

    2017-04-01

    In this study, the white-rot fungus Cyathus bulleri was cultivated on low-cost agro-residues, namely wheat bran (WB), wheat straw (WS), and domestic waste orange peel (OP) for production of ligninolytic enzymes. Of the three substrates, WB and OP served as good materials for the production of laccase with no requirement of additional carbon or nitrogen source. Specific laccase activity of 94.4 U mg -1 extracellular protein and 21.01 U mg -1 protein was obtained on WB and OP, respectively. Maximum decolorization rate of 13.6 μmol h -1  U -1 laccase for reactive black 5 and 22.68 μmol h -1  U -1 laccase for reactive orange 16 (RO) was obtained with the WB culture filtrate, and 11.7 μmol h -1  U -1 laccase for reactive violet 5 was observed with OP culture filtrate. Importantly, Kiton blue A (KB), reported not to be amenable to enzymatic degradation, was degraded by culture filtrate borne activities. Products of degradation of KB and RO were identified by mass spectrometry, and a pathway of degradation proposed. WB-grown culture filtrate decolorized and detoxified real and simulated textile effluents by about 40%. The study highlights the use of inexpensive materials for the production of enzymes effective on dyes and effluents.

  20. Dechlorination of polychlorinated biphenyls by iron and its oxides.

    Science.gov (United States)

    Sun, Yifei; Liu, Xiaoyuan; Kainuma, Masashi; Wang, Wei; Takaoka, Masaki; Takeda, Nobuo

    2015-10-01

    The decomposition efficiency of polychlorinated biphenyls (PCBs) was determined using elemental iron (Fe) and three iron (hydr)oxides, i.e., α-Fe2O3, Fe3O4, and α-FeOOH, as catalysts. The experiments were performed using four distinct PCB congeners (PCB-209, PCB-153, and the coplanar PCB-167 and PCB-77) at temperatures ranging from 180 °C to 380 °C and under an inert, oxidizing or reducing atmosphere composed of N2, N2+O2, or N2+H2. From these three options N2 showed to provide the best reaction atmosphere. Among the iron compounds tested, Fe3O4 showed the highest activity for decomposing PCBs. The decomposition efficiencies of PCB-209, PCB-167, PCB-153, and PCB-77 by Fe3O4 in an N2 atmosphere at 230 °C were 88.5%, 82.5%, 69.9%, and 66.4%, respectively. Other inorganic chlorine (Cl) products which were measured by the amount of inorganic Cl ions represented 82.5% and 76.1% of the reaction products, showing that ring cleavage of PCBs was the main elimination process. Moreover, the dechlorination did not require a particular hydrogen donor. We used X-ray photoelectron spectroscopy to analyze the elemental distribution at the catalyst's surface. The O/Fe ratio influenced upon the decomposition efficiency of PCBs: the lower this ratio, the higher the decomposition efficiency. X-ray absorption near edge structure spectra showed that α-Fe2O3 effectively worked as a catalyst, while Fe3O4 and α-FeOOH were consumed as reactants, as their final state is different from their initial state. Finally, a decomposition pathway was postulated in which the Cl atoms in ortho-positions were more difficult to eliminate than those in the para- or meta-positions. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Accumulation of metabolites during bacterial degradation of PAH-mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Vila, J.; Lopez, Z.; Bauza, J.I. [Universitat de Barcelona (Spain). Department de Microbiologia; Minguillon, C. [Parc Cientific de Barcelona (ES). Institut de Recerca de Barcelona (IRB-PCB); Grifoll, M.

    2003-07-01

    In a previous work we identified a number of metabolites accumulated during growth in pyrene by Mycobacterium sp. AP1, and proposed a metabolic pathway for pyrene utilization. In order to confirm and complete this pathway we have isolated and identified the pyrene-degrading strains Mycobacterium sp. PGP2, CP1 and CP2. During growth on pyrene, strains AP1, PGP2, CP1 and CP2 accumulated 4,5-cis-pyrene-dihydrodiol, 4,5-phenanthrene dicarboxylic acid, 4-phenanthrene carboxylic acid, 3,4-dihydroxy-3-hydrophenanthrene-4-carboxylic acid, phthalic acid, and 6,6'-dihydroxy-2,2'-biphenyl dicarboxylic acid. Strains AP1, PGP2, CP1 and CP2 also grew on fluoranthene accumulating acenaphthenone, naphthalene-1,8-dicarboxylic acid, 9-fluorenone-1-carboxylic acid, Z-9-carboxymethylenefluorene-1-carboxylic acid and benzene-1,2,3-tricarboxylic acid. Similar metabolites were produced during growth onf fluoranthene by the Gram-positive strains CFt2 and CFt6, isolated by their capability of using this PAH as a sole source of carbon and energy. These fluoranthene-degrading strains also accumulated cis-1,9a-dihydroxy-1-hydrofluorene-9-one-8-carboxylic acid. In addition to pyrene and fluoranthene, all pyrene-degrading utilized phenanthrene as a sole source of carbon and energy, while the fluoranthene-degrading strains were unable to utilize pyrene or phenanthrene. Mycobacterium sp. AP1 acted on a wide range of PAHs, accumulating aromatic dicarboxylic acids, hydroxyacids, and ketones resulting from dioxygenation and ortho-cleavage, dioxygenation and meta-cleavage, and monooxygenation reactions. In cultures of strains AP1 and CP1 with a defined PAH-mixture only 20% removal of the parent compounds was observed. Analysis of acidic extracts showed the accumulation of the anticipated aromatic acids, suggesting that accumulation of acidic compounds could prevent further degradation of the mixture. Those results led us to isolation of strains DF11 and OH3, able to grow on the selected

  2. Consolidated PCBs [polychlorinated biphenyls] improves waste control

    International Nuclear Information System (INIS)

    Smith, E.

    1991-01-01

    Consolidation of polychlorinated biphenyl (PCB) wastes is recommended for improving ownership control of wastes, eliminating PCB storage sites, and increasing cost-effectiveness of waste management. In Ontario, sites receiving the waste must be owned by the waste generator and registered as a PCB site. All PCBs must be removed from a site with no contaminated materials or wastes left behind, which requires a thorough site assessment to identify wastes prior to removal, a sampling and analytical scheme if necessary, and an approved plan for site cleanup. If large volumes of PCB-contaminated oil are involved, it may be cost-effective to put oil from several sites into bulk tanks and thus avoid the need to handle and decontaminate a large number of drums. With low volumes of oil, it may be possible to move the waste to another site where mobile PCB destruction is taking place. It also may be possible to get approval to blend high-level PCB liquids with mineral oil to reduce the PCB concentration to a level where chemical decontamination is allowed. For large volumes of high-level PCB wastes, consolidation will be necessary simply because of the high costs of mobilizing an incinerator and the requirement for public hearings for each incineration project. To make such a project cost-effective, PCB wastes will have to be concentrated from a large geographic area. 1 fig

  3. New technologies for PCB [polychlorinated biphenyl] decontamination

    International Nuclear Information System (INIS)

    Webber, I.

    1993-01-01

    Polychlorinated biphenyls (PCB) were mixed with chlorobenzenes to reduce viscosity and provide for both electrical insulation and convective heat transfers. These mixtures were known as askarels, and ca 99.8% of PCBs used in electrical applications are contained in askarel-filled transformers and capacitors. It is estimated that there are ca 180 million gal of PCB-contaminated oil distributed through over 3 million transformers in the USA. Technology used for decontaminating these transformers depends on the concentration of the PCB contamination. At low PCB concentrations of up to ca 2,000 ppM, chemical methods can be used; at higher concentrations, alternative disposal options become more attractive. For chemical treatment, a small mobile unit using quick-reacting reagents has been developed for on-site decontamination. For highly contaminated transformers, retrofilling is very attractive since the owner's liability is minimized at minimum cost. Conventional flush/drain procedures have such drawbacks as the inability to remove oil trapped in windings and the leaching of trapped PCBs back into the uncontaminated retrofill oil over time. A new process has been developed to solve the leaching problem and to decontaminate the drained askarel at room temperature using a catalyst. An alternative disposal strategy involves dismantling the transformer carcass, incinerating non-recyclable materials, and cleaning the metals and wire with solvent. 8 figs

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

    NARCIS (Netherlands)

    Poelarends, GJ; Kulakov, LA; Larkin, MJ; van Hylckama Vlieg, Johan E.T.; Janssen, DB

    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

  5. 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

  6. 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

  7. Biofilms at work: Bio-, phyto- and rhizoremediation approaches for soils contaminated with polychlorinated biphenyls

    Directory of Open Access Journals (Sweden)

    Merily Horwat

    2015-09-01

    Full Text Available Organohalide contaminants such as polychlorinated biphenyls (PCBs have been released into the environment for decades due to anthropogenic activities, but are also naturally produced in small amounts through volcanic eruptions and geochemical processes. Although toxic to humans and other organisms, the natural production of these compounds has resulted in the evolution of naturally occurring organohalide-respiring bacteria that possess the enzymes necessary to degrade PCB compounds to non-toxic products. The efficiency of PCB degradation can be improved by facilitating the formation of organohalide-respiring biofilms. During biofilm colonization on a surface or interface, bacteria are encased in an extracellular polymeric substance (EPS or “slime,” which allows them to share nutrients and remain protected from environmental stresses. Effective bioremediation of PCBs involves facilitation of biofilm growth to promote cooperation between bacteria, which can be further enhanced by the presence of certain plant species. This review aims to give an overview of biofilm processes involved in the detoxification of PCBs including anaerobic and aerobic PCB degradation by bacteria as well as the ability of plants to stimulate microbial activity and degradation (rhizoremediation and phytoremediation.

  8. 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

  9. Single gene retrieval from thermally degraded DNA

    Indian Academy of Sciences (India)

    Unknown

    DNA thermal degradation was shown to occur via a singlet oxygen pathway. A comparative study of the ther- mal degradation of cellular DNA and isolated DNA showed that cellular ..... definite level of energy (e.g. depurination active energy,.

  10. Ferrocene-catalyzed heterogeneous Fenton-like degradation mechanisms and pathways of antibiotics under simulated sunlight: A case study of sulfamethoxazole.

    Science.gov (United States)

    Li, Yingjie; Zhang, Biaojun; Liu, Xiangliang; Zhao, Qun; Zhang, Heming; Zhang, Yuechao; Ning, Ping; Tian, Senlin

    2018-07-05

    Readily-available and efficient catalyst is essential for activating oxidants to produce reactive species for deeply remediating water bodies contaminated by antibiotics. In this study, Ferrocene (Fc) was introduced to establish a heterogeneous photo-Fenton system for the degradation of sulfonamide antibiotics, taking sulfamethoxazole as a representative. Results showed that the removal of sulfamethoxazole was effective in Fc-catalyzed photo-Fenton system. Electron spin resonance and radical scavenging experiments verified that there was a photoindued electron transfer process from Fc to H 2 O 2 and dissolved oxygen resulting in the formation of OH that was primarily responsible for the degradation of sulfamethoxazole. The reactions of OH with substructure model compounds of sulfamethoxazole unveiled that aniline moiety was the preferable reaction site of sulfamethoxazole, which was verified by the formation of hydroxylated product and the dimer of sulfamethoxazole in Fc-catalyzed photo-Fenton system. This heterogeneous photo-Fenton system displayed an effective degradation efficiency even in a complex water matrices, and Fc represented a long-term stability by using the catalyst for multiple cycles. These results demonstrate that Fc-catalyzed photo-Fenton oxidation may be an efficient approach for remediation of wastewater containing antibiotics. Copyright © 2018. Published by Elsevier B.V.

  11. 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

  12. 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.

  13. 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...

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

    Science.gov (United States)

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

  15. 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.

  16. 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.

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

    Directory of Open Access Journals (Sweden)

    Federici Ermanno

    2012-03-01

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

  18. 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

  19. 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.

  20. Advances and perspective in bioremediation of polychlorinated biphenyl-contaminated soils.

    Science.gov (United States)

    Sharma, Jitendra K; Gautam, Ravindra K; Nanekar, Sneha V; Weber, Roland; Singh, Brajesh K; Singh, Sanjeev K; Juwarkar, Asha A

    2018-06-01

    In recent years, microbial degradation and bioremediation approaches of polychlorinated biphenyls (PCBs) have been studied extensively considering their toxicity, carcinogenicity and persistency potential in the environment. In this direction, different catabolic enzymes have been identified and reported for biodegradation of different PCB congeners along with optimization of biological processes. A genome analysis of PCB-degrading bacteria has led in an improved understanding of their metabolic potential and adaptation to stressful conditions. However, many stones in this area are left unturned. For example, the role and diversity of uncultivable microbes in PCB degradation are still not fully understood. Improved knowledge and understanding on this front will open up new avenues for improved bioremediation technologies which will bring economic, environmental and societal benefits. This article highlights on recent advances in bioremediation of PCBs in soil. It is demonstrated that bioremediation is the most effective and innovative technology which includes biostimulation, bioaugmentation, phytoremediation and rhizoremediation and acts as a model solution for pollution abatement. More recently, transgenic plants and genetically modified microorganisms have proved to be revolutionary in the bioremediation of PCBs. Additionally, other important aspects such as pretreatment using chemical/physical agents for enhanced biodegradation are also addressed. Efforts have been made to identify challenges, research gaps and necessary approaches which in future, can be harnessed for successful use of bioremediation under field conditions. Emphases have been given on the quality/efficiency of bioremediation technology and its related cost which determines its ultimate acceptability.

  1. 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

  2. Characterization of 3-Ketosteroid 9α-Hydroxylase, a Rieske Oxygenase in the Cholesterol Degradation Pathway of Mycobacterium tuberculosis*S⃞

    OpenAIRE

    Capyk, Jenna K.; D'Angelo, Igor; Strynadka, Natalie C.; Eltis, Lindsay D.

    2009-01-01

    KshAB (3-Ketosteroid 9α-hydroxylase) is a two-component Rieske oxygenase (RO) in the cholesterol catabolic pathway of Mycobacterium tuberculosis. Although the enzyme has been implicated in pathogenesis, it has largely been characterized by bioinformatics and molecular genetics. Purified KshB, the reductase component, was a monomeric protein containing a plant-type [2Fe-2S] cluster and FAD. KshA, the oxygenase, was a homotrimer containing a Rieske [2Fe-2S] cluster and m...

  3. Polychlorinated biphenyl sources, environmental levels, and exposures in school buildings

    Science.gov (United States)

    Background: Building materials and components containing polychlorinated biphenyls (PCBs) were used in some U.S. school buildings until the late 1970s and may be present today. There is limited information on source factors and occupant exposures. Methods: Analysis of PCBs in mat...

  4. 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 ...

  5. 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

  6. 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

  7. 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

  8. 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...

  9. 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

  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. 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.

  12. 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...

  13. 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...

  14. Genetic and functional characterization of a novel meta-pathway for degradation of naringenin in Herbaspirillum seropedicae SmR1.

    Science.gov (United States)

    Maria Marin, Anelis; de la Torre, Jésus; Ricardo Marques Oliveira, Alfredo; Barison, Andersson; Satie Chubatsu, Leda; Adele Monteiro, Rose; de Oliveira Pedrosa, Fabio; Maltempi de Souza, Emanuel; Wassem, Roseli; Duque, Estrella; Ramos, Juan-Luis

    2016-12-01

    In this study, a random mutant library of Herbaspirillum seropedicae SmR1 was constructed by Tn5 insertion and a mutant incapable of utilizing naringenin as a carbon source was isolated. The Tn5 transposon was found to be inserted in the fdeE gene (Hsero_1007), which encodes a monooxygenase. Two other mutant strains in fdeC (Hsero_1005) and fdeG (Hsero_1009) genes coding for a dioxygenase and a putative cyclase, respectively, were obtained by site-directed mutagenesis and then characterized. Liquid Chromatography coupled to mass spectrometry (LC-MS)/MS analyses of culture supernatant from the fdeE mutant strain revealed that naringenin remained unaltered, suggesting that the FdeE protein is involved in the initial step of naringenin degradation. LC-MS/MS analyses of culture supernatants from the wild-type (SmR1) and FdeC deficient mutant suggested that in H. seropedicae SmR1 naringenin is first mono-oxygenated by the FdeE protein, to produce 5,7,8-trihydroxy-2-(4-hydroxyphenyl)-2,3-dihydro-4H-chromen-4-one, that is subsequently dioxygenated and cleaved at the A-ring by the FdeC dioxygenase, since the latter compound accumulated in the fdeC strain. After meta-cleavage of the A-ring, the subsequent metabolic steps generate oxaloacetic acid that is metabolized via the tricarboxylic acid cycle. This bacterium can also modify naringenin by attaching a glycosyl group to the B-ring or a methoxy group to the A-ring, leading to the generation of dead-end products. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  15. β–Hydroxy β–Methylbutyrate Improves Dexamethasone-Induced Muscle Atrophy by Modulating the Muscle Degradation Pathway in SD Rat

    Science.gov (United States)

    Choi, Yeon Ja; Park, Min Hi; Jang, Eun Ji; Park, Chan Hum; Yoon, Changshin; Kim, Nam Deuk; Kim, Mi Kyung; Chung, Hae Young

    2014-01-01

    Skeletal muscle atrophy results from various conditions including high levels of glucocorticoids, and β–hydroxy β–methylbutyrate (HMB; a metabolite of leucine) is a potent therapeutical supplement used to treat various muscle disorders. Recent studies have demonstrated that HMB inhibits dexamethasone-induced atrophy in cultured myotubes, but its effect on dexamethasone-induced muscle atrophy has not been determined in vivo. In the present study, we investigated the effect of HMB on dexamethasone-induced muscle atrophy in rats. Treatment with dexamethasone weakened grip strengths and increased muscle damage as determined by increased serum creatine kinase levels and by histological analysis. Dexamethasone treatment also reduced both soleus and gastrocnemius muscle masses. However, HMB supplementation significantly prevented reductions in grip strengths, reduced muscle damage, and prevented muscle mass and protein concentration decrease in soleus muscle. Biochemical analysis demonstrated that dexamethasone markedly increased levels of MuRF1 protein, which causes the ubiquitination and degradation of MyHC. Indeed, dexamethasone treatment decreased MyHC protein expression and increased the ubiquitinated-MyHC to MyHC ratio. However, HMB supplementation caused the down-regulations of MuRF1 protein and of ubiquitinated-MyHC. Furthermore, additional experiments provided evidence that HMB supplementation inhibited the nuclear translocation of FOXO1 induced by dexamethasone, and showed increased MyoD expression in the nuclear fractions of soleus muscles. These findings suggest that HMB supplementation attenuates dexamethasone-induced muscle wasting by regulating FOXO1 transcription factor and subsequent MuRF1 expression. Accordingly, our results suggest that HMB supplementation could be used to prevent steroid myopathy. PMID:25032690

  16. Ordered bulk degradation via autophagy

    DEFF Research Database (Denmark)

    Dengjel, Jörn; Kristensen, Anders Riis; Andersen, Jens S

    2008-01-01

    During amino acid starvation, cells undergo macroautophagy which is regarded as an unspecific bulk degradation process. Lately, more and more organelle-specific autophagy subtypes such as reticulophagy, mitophagy and ribophagy have been described and it could be shown, depending on the experimental...... at proteasomal and lysosomal degradation ample cross-talk between the two degradation pathways became evident. Degradation via autophagy appeared to be ordered and regulated at the protein complex/organelle level. This raises several important questions such as: can macroautophagy itself be specific and what...

  17. 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)

  18. Characterization of 3-Ketosteroid 9α-Hydroxylase, a Rieske Oxygenase in the Cholesterol Degradation Pathway of Mycobacterium tuberculosis*S⃞

    Science.gov (United States)

    Capyk, Jenna K.; D'Angelo, Igor; Strynadka, Natalie C.; Eltis, Lindsay D.

    2009-01-01

    KshAB (3-Ketosteroid 9α-hydroxylase) is a two-component Rieske oxygenase (RO) in the cholesterol catabolic pathway of Mycobacterium tuberculosis. Although the enzyme has been implicated in pathogenesis, it has largely been characterized by bioinformatics and molecular genetics. Purified KshB, the reductase component, was a monomeric protein containing a plant-type [2Fe-2S] cluster and FAD. KshA, the oxygenase, was a homotrimer containing a Rieske [2Fe-2S] cluster and mononuclear ferrous iron. Of two potential substrates, reconstituted KshAB had twice the specificity for 1,4-androstadiene-3,17-dione as for 4-androstene-3,17-dione. The transformation of both substrates was well coupled to the consumption of O2. Nevertheless, the reactivity of KshAB with O2 was low in the presence of 1,4-androstadiene-3,17-dione, with a kcat/KmO2 of 2450 ± 80 m–1 s–1. The crystallographic structure of KshA, determined to 2.3Å, revealed an overall fold and a head-to-tail subunit arrangement typical of ROs. The central fold of the catalytic domain lacks all insertions found in characterized ROs, consistent with a minimal and perhaps archetypical RO catalytic domain. The structure of KshA is further distinguished by a C-terminal helix, which stabilizes subunit interactions in the functional trimer. Finally, the substrate-binding pocket extends farther into KshA than in other ROs, consistent with the large steroid substrate, and the funnel accessing the active site is differently orientated. This study provides a solid basis for further studies of a key steroid-transforming enzyme of biotechnological and medical importance. PMID:19234303

  19. 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

  20. Role of inhalation in exposure to polychlorinated biphenyls (PCBs)

    International Nuclear Information System (INIS)

    Monarca, S.; Dominici, L.; Fatigoni, C.

    2007-01-01

    Polychlorinated biphenyls (PCBs) are a group of aromatic compounds consisting of a biphenyl variously chlorinated. Industrial production of PCBs started in 1929 and stopped in the second half of the '70s in USA and in the late 80's and 90's in Europe. PCBs are ubiquitous pollutants. The way of human exposure to PCBs is a matter of discussion. Scientific data show that the greater exposure occurs through diet. However, other available data suggest a not marginal role of the inhalation exposure. The sources of PCBs to which population are exposed depend on the amount of redistribution of these compounds released in the environment. The aim of this work is to highlight numerous studies proving that the intake of PCBs by inhalation cannot be neglected, in particular in heavily industrialized areas and where the concentration of PCBs in the environmental matrices is particularly high

  1. Anaerobic Dehalogenation of Hydroxylated Polychlorinated Biphenyls by Desulfitobacterium dehalogenans

    OpenAIRE

    Wiegel, Juergen; Zhang, Xiaoming; Wu, Qingzhong

    1999-01-01

    Ten years after reports on the existence of anaerobic dehalogenation of polychlorinated biphenyls (PCBs) in sediment slurries, we report here on the rapid reductive dehalogenation of para-hydroxylated PCBs (HO-PCBs), the excreted main metabolites of PCB in mammals, which can exhibit estrogenic and antiestrogenic activities in humans. The anaerobic bacterium Desulfitobacterium dehalogenans completely dehalogenates all flanking chlorines (chlorines in ortho position to the para-hydroxyl group) ...

  2. Polychlorinated biphenyl reduction in lake trout by irradiation and broiling

    International Nuclear Information System (INIS)

    Cichy, R.F.; Zabik, M.E.; Weaver, C.M.

    1979-01-01

    The Great Lakes Environmental contaminants surveys (1974-1975) have concluded that excessive concentrations of polychlorinated biphenyls (PCBs) are present in a specific species of lake trout (Salvelinus namaycush). Over 30 ppM of PCBs have been detected in the edible fillet of this fat trout. The objective of this study was to determine the effect of gamma irradiation combined with broiling on the levels of PCBs in lake trout fillets

  3. 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.

  4. Reactivity of polychlorinated biphenyls in nucleophilic and electrophilic substitutions

    Energy Technology Data Exchange (ETDEWEB)

    Gorbunova, Tatyana I., E-mail: gorbunova@ios.uran.ru [I. Ya. Postovskii Institute of Organic Synthesis, Ural Branch, Russian Academy of Sciences, Kovalevskoy St., 22, Ekaterinburg 620990 (Russian Federation); Subbotina, Julia O. [Ural Federal University named after the first President of Russia B.N. Yeltsin, Mira St., 19, Ekaterinburg 620002 (Russian Federation); Saloutin, Viktor I.; Chupakhin, Oleg N. [I. Ya. Postovskii Institute of Organic Synthesis, Ural Branch, Russian Academy of Sciences, Kovalevskoy St., 22, Ekaterinburg 620990 (Russian Federation)

    2014-08-15

    Graphical abstract: - Highlights: • Quantum chemical calculations were carried out for PCBs congeners. • Calculated descriptors were used to explain the PCBs reactivity in S{sub N} and S{sub E} substitutions. • Obtained data were used to estimate the PCBs reactivity in the S{sub N} reactions. • Calculated descriptors were insufficient to explain the PCBs reactivity in the S{sub E} reactions. • New neutralization methods of the large-capacity PCBs were discussed. - Abstract: To explain the chemical reactivity of polychlorinated biphenyls in nucleophilic (S{sub N}) and electrophilic (S{sub E}) substitutions, quantum chemical calculations were carried out at the B3LYP/6-31G(d) level of the Density Functional Theory in gas phase. Carbon atomic charges in biphenyl structure were calculated by the Atoms-in-Molecules method. Chemical hardness and global electrophilicity index parameters were determined for congeners. A comparison of calculated descriptors and experimental data for congener reactivity in the S{sub N} and S{sub E} reactions was made. It is shown that interactions in the S{sub N} mechanism are reactions of the hard acid–hard base type, these are the most effective in case of highly chlorinated substrates. To explain the congener reactivity in the S{sub E} reactions, correct descriptors were not established. The obtained results can be used to carry out chemical transformations of the polychlorinated biphenyls in order to prepare them for microbiological destruction or preservation.

  5. 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

  6. Complete Reductive Dehalogenation of Brominated Biphenyls by Anaerobic Microorganisms in Sediment

    Science.gov (United States)

    Bedard, Donna L.; Van Dort, Heidi M.

    1998-01-01

    We sought to determine whether microorganisms from the polychlorinated biphenyl (PCB)-contaminated sediment in Woods Pond (Lenox, Mass.) could dehalogenate brominated biphenyls. The PCB dechlorination specificities for the microorganisms in this sediment have been well characterized. This allowed us to compare the dehalogenation specificities for brominated biphenyls and chlorinated biphenyls within a single sediment. Anaerobic sediment microcosms were incubated separately at 25°C with 16 different mono- to tetrabrominated biphenyls (350 μM) and disodium malate (10 mM). Samples were extracted and analyzed by gas chromatography with an electron capture detector and a mass spectrometer detector at various times for up to 54 weeks. All of the tested brominated biphenyls were dehalogenated. For most congeners, including 2,6-dibromobiphenyl (26-BB) and 24-25-BB, the dehalogenation began within 1 to 2 weeks. However, for 246-BB and 2-2-BB, debromination was first observed at 7 and 14 weeks, respectively. Most intermediate products did not persist, but when 2-2-BB was produced as a dehalogenation product, it persisted for at least 15 weeks before it was dehalogenated to 2-BB and then to biphenyl. The dehalogenation specificities for brominated and chlorinated biphenyls were similar: meta and para substituents were generally removed first, and ortho substituents were more recalcitrant. However, the brominated biphenyls were better dehalogenation substrates than the chlorinated biphenyls. All of the tested bromobiphenyls, including those with ortho and unflanked meta and para substituents, were ultimately dehalogenated to biphenyl, whereas their chlorinated counterparts either were not dehalogenation substrates or were only partially dehalogenated. Our data suggest that PCB-dechlorinating microorganisms may be able to dehalogenate brominated biphenyls and may exhibit a relaxed specificity for these substrates. PMID:16349530

  7. 4-Substituted-2-Methoxyphenol: Suitable Building Block to Prepare New Bioactive Natural-like Hydroxylated Biphenyls.

    Science.gov (United States)

    Dettori, Maria Antonietta; Fabbri, Davide; Pisano, Marina; Rozzo, Carla; Palmieri, Giuseppe; Dess, Alessandro; Dallocchio, Roberto; Delogu, Giovanna

    2015-02-01

    A small collection of eugenol- and curcumin-analog hydroxylated biphenyls was prepared by straightforward methods starting from natural 4-substituted-2-methoxyphenols and their antitumoral activity was evaluated in vitro . Two curcumin-biphenyl derivatives showed interesting growth inhibitory activities on different malignant melanoma cell lines with IC 50 ranging from 13 to 1 µM. Preliminary molecular modeling studies were carried out to evaluate conformations and dihedral angles suitable for antiproliferative activity in hydroxylated biphenyls bearing a side aliphatic chain.

  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. 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.

  11. [Comparative study of aromatic ring meta-cleavage enzymes in Pseudomonas strains with plasmid and chromosomal genetic control of the catabolism of biphenyl and m-toluate].

    Science.gov (United States)

    Selifonov, S A; Starozoĭtov, I I

    1990-12-01

    It was shown that two different enzymes of aromatic ring oxidative meta-cleavage (2,3-dihydroxybiphenyl-1,2-dioxygenase), DBO and catechol-2,3-dioxygenase, C230) function in Pseudomonas strains with a plasmid and chromosomal genetic control of biphenyl and toluate catabolism. A comparative analysis of DBO's and C230's expressed by the pBS241 biphenyl degradative plasmid in P. putida BS893, pBS311 in P. putida U83, chromosomal genes in P. putida BF and C230 from P. putida PaW160 (pWWO) was carried out. It was found that the DBO's of all strains under study are highly specialized enzymes in respect of 2,3-dihydroxybiphenyl cleavage and are also able to cleave 3-methyl-catechol and catechol (but not 4-methylcatechol) at low rates. In contrast with DBO's, in Pseudomonas strains the substrate specificities of all C230's are variable. The C230's expressed by the D-plasmids pBS241 and pBC311 have a moderate affinity for catechol, 3-methyl- and 4-methylcatechol, but are unable to cleave 2,3-dihydroxybiphenyl. The C230 which is encoded by the chromosomal structure gene from P. putida BF is very similar to C230 which codes for the TOL-plasmid pWWO. These plasmid differ from C230's expressed by biphenyl D-plasmids due to their capability to cleave 2,3-dihydroxybiphenyl in addition to catechol cleavage. All DBO's and C230's under study possess a number of properties that are typical for the enzymes having an oxidative meta-cleaving effect. The different roles of these enzymes in biphenyl and toluate catabolism in Pseudomonas strains are discussed.

  12. 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.

  13. Selective scanning tunnelling microscope electron-induced reactions of single biphenyl molecules on a Si(100) surface.

    Science.gov (United States)

    Riedel, Damien; Bocquet, Marie-Laure; Lesnard, Hervé; Lastapis, Mathieu; Lorente, Nicolas; Sonnet, Philippe; Dujardin, Gérald

    2009-06-03

    Selective electron-induced reactions of individual biphenyl molecules adsorbed in their weakly chemisorbed configuration on a Si(100) surface are investigated by using the tip of a low-temperature (5 K) scanning tunnelling microscope (STM) as an atomic size source of electrons. Selected types of molecular reactions are produced, depending on the polarity of the surface voltage during STM excitation. At negative surface voltages, the biphenyl molecule diffuses across the surface in its weakly chemisorbed configuration. At positive surface voltages, different types of molecular reactions are activated, which involve the change of adsorption configuration from the weakly chemisorbed to the strongly chemisorbed bistable and quadristable configurations. Calculated reaction pathways of the molecular reactions on the silicon surface, using the nudge elastic band method, provide evidence that the observed selectivity as a function of the surface voltage polarity cannot be ascribed to different activation energies. These results, together with the measured threshold surface voltages and the calculated molecular electronic structures via density functional theory, suggest that the electron-induced molecular reactions are driven by selective electron detachment (oxidation) or attachment (reduction) processes.

  14. 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.

  15. Analytical method of polychlorinated biphenyls(PCBs) in transformer oil

    Energy Technology Data Exchange (ETDEWEB)

    Shin, S.K. [National Institute of Environmental Research, Incheon (Korea); Kim, H.J.; Chung, D.; Kim, K.S.; Kim, J.K.; Chung, Y.H.; Chung, I.R.

    2004-09-15

    Polychlorinated biphenyls (PCBs) is a chlorinated biphenyl compound with the general formula C{sub 12}H{sub 10-n}/Cl{sub n}. PCBs generally occur as mixtures, where n can vary from 1 to 10. The 10 sites available for possible chlorine substitution result in 209 possible PCB congeners. There is now considerable concern regarding; the presence of PCB congeners in insulating oils used within large-scale electrical supply systems. Due to its outstanding chemical and thermal stabilities and electrical insulation properties, the commercial and industrial products of polychlorinated biphenyls (PCBs), such as Aroclors, Kaneclors, Clophens, Phenaclors etc., had been widely used as thermal oil and transformer oil from 1930s until the 1970s. PCBs from a group of persistent organic pollutants of the environment, especially dangerous to living organisms due to high toxicity, persistency, and bio-concentration in adipose tissue. Despite of this fact, PCB-contaminated oils are still commonly encountered partly because PCBs used as dielectric liquids in transformer and condenser. The source of PCBs in environments can range from used transformer oils or dielectric liquids to liquid wastes, and some PCBs contamination is occurred due to the re-use of incompletely reconditioned oil. The current action plan of Republic of Korea dictates that organizations with electrical equipment contaminated with more than 2 mg/L PCBs will need to treat as PCBs-containing wastes, and 50mg/L of PCBs or PCBs equivalent to be treated as a pure PCB preparation. In this study, transformer oils analyzed based on guideline for PCBs analytical method of transformer oil in Korea.

  16. 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.

  17. Decomposition of polychlorinated biphenyls in soil with a dispersion mixture of metallic calcium and calcium oxide.

    Science.gov (United States)

    Mitoma, Yoshiharu; Mallampati, Srinivasa Reddy; Miyata, Hideaki; Kakeda, Mitsunori

    2013-02-01

    This study describes the decomposition of polychlorinated biphenyls (PCBs) in soil with dispersion mixtures of metallic calcium (Ca) and calcium oxide (CaO) at different temperatures. In these experiments, naturally moisturized and contaminated soil (1.0 g [31 ppm PCBs]), CaO (dried 2.0 wt%), and metallic Ca (0.01 g [0.25 mmol]) were introduced into a stainless steel pressure reactor under 0.1 MPa N(2) gas. The mixtures were stirred magnetically and heated at 260, 280, and 300 °C, respectively. Soil treatment with metallic Ca and CaO under various temperature conditions is extremely effective for degrading existing PCBs. Decomposition resulted from dechlorination (DC). Initial moisture in soil acted as a hydrogen source during stirring. Soil moisture can be beneficial for hydrodechlorination in the presence of metallic Ca and CaO. Furthermore, metallic Ca and CaO can greatly increase the number of collisions and mutual refinement. Treatment at 260, 280, and 300 °C combined with metallic Ca and CaO is effective for the decomposition (approximately 95 % DC) of PCBs in soil under natural moisture conditions.

  18. 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.

  19. Detailed analysis of polybrominated biphenyl congeners in bird eggs from Norway

    International Nuclear Information System (INIS)

    Vetter, Walter; Recke, Roland von der; Herzke, Dorte; Nygard, Torgeir

    2008-01-01

    Individual eggs of six species of birds from Norway representing different food chains were analysed for residues of polybrominated biphenyls (PBBs). In all species, the residue pattern was dominated by hexaBBs. The dominating congeners were PBB 153, PBB 154, and PBB 155. Whereas PBB 153 is present in technical hexabromobiphenyl, PBB 154 and PBB 155 are formed by the reductive debromination of decabromobiphenyl. This was evidenced by the detection of several heptaBBs and octaBBs all of which are typical degradation intermediates of PBB 209. Hepta- and octaBBs were more than one order of magnitude less abundant than the hexaBBs. The second most prevailing homologue group was pentaBBs. The most relevant pentabrominated isomers were PBB 99 and PBB 101. Concentrations of the three hexaBBs - PBB 153, PBB 154, and PBB 155 - amounted to 1.3-13 ng/g wet weight or 3-23% of the contamination with polybrominated diphenyl ethers. - We provide for the first time detailed information on the PBB congeners present in eggs of bird of prey, and quantified three hexabromo congeners

  20. TALSPEAK Solvent Degradation

    Energy Technology Data Exchange (ETDEWEB)

    Leigh R. Martin; Bruce J. Mincher

    2009-09-01

    Understanding the radiolytic degradation behavior of organic molecules involved in new or existing schemes for the recycle of used nuclear fuels is of significant interest for sustaining a closed nuclear fuel cycle. Here we have conducted several lines of investigation to begin understanding the effects of radiolysis on the aqueous phase of the TALSPEAK process for the separation of the trivalent lanthanides from the trivalent actinides. Using the 60-Co irradiator at the INL, we have begun to quantify the effects of radiation on the aqueous phase complexants used in this separation technique, and how this will affect the actinide lanthanide separation factor. In addition we have started to develop methodologies for stable product identification, a key element in determining the degradation pathways. We have also introduced a methodology to investigate the effects of alpha radiolysis that has previously received limited attention.

  1. Biobatteries and biofuel cells with biphenylated carbon nanotubes

    Science.gov (United States)

    Stolarczyk, Krzysztof; Kizling, Michał; Majdecka, Dominika; Żelechowska, Kamila; Biernat, Jan F.; Rogalski, Jerzy; Bilewicz, Renata

    2014-03-01

    Single-walled carbon nanotubes (SWCNTs) covalently biphenylated are used for the construction of cathodes in a flow biobattery and in flow biofuel cell. Zinc covered with a hopeite layer is the anode in the biobattery and glassy carbon electrode covered with bioconjugates of single-walled carbon nanotubes with glucose oxidase and catalase is the anode of the biofuel cell. The potentials of the electrodes are measured vs. the Ag/AgCl reference electrode under changing loads of the fuel cell/biobattery. The power density of the biobattery with biphenylated nanotubes at the cathode is ca. 0.6 mW cm-2 and the open circuit potential is ca. 1.6 V. In order to obtain larger power densities and voltages three biobatteries are connected in a series which leads to the open circuit potential of ca. 4.8 V and power density 2.1 mW cm-2 at 3.9 V under 100 kΩ load. The biofuel cell shows power densities of ca. 60 μW cm-2 at 20 kΩ external resistance but the open circuit potential for such biofuel cell is only 0.5 V. The biobattery showing significantly larger power densities and open circuit voltages are especially useful for testing novel cathodes and applications such as powering units for clocks and sensing devices.

  2. Momentum space analysis of the electronic structure of biphenyl

    International Nuclear Information System (INIS)

    Morini, F; Shojaei, S H Reza; Deleuze, M S

    2014-01-01

    The results of a yet to come experimental study of the electronic structure of biphenyl employing electron momentum spectroscopy (EMS) have been theoretically predicted, taking into account complications such as structural mobility in the electronic ground state, electronic correlation and relaxation, and a dispersion of the inner-valence ionization intensity to electronically excited (shake-up) configurations in the cation. The main purpose of this work is to explore the current limits of EMS in unraveling details of the molecular structure, namely the torsional characteristics of large and floppy aromatic molecules. At the benchmark ADC(3)/cc-pVDZ level of theory, the influence of the twist angle between the two phenyl rings is found to be extremely limited, except for individual orbital momentum profiles corresponding to ionization lines at electron binding energies ranging from 15 to 18 eV. When taking band overlap effects into account, this influence is deceptively far too limited to allow for any experimental determination of the torsional characteristics of biphenyl by means of EMS. (paper)

  3. PHOTOCATALYTIC DEGRADATION OF CRYSTAL VIOLET BY ...

    African Journals Online (AJOL)

    In recent years, removal of undesirable organic contaminants from water and wastewater is ... accidental leakage of tanks containing pollutants, etc. ..... Consideration of reaction pathways and degradation rates is critical for detection of waste.

  4. Substituted N-(biphenyl-4'-yl)methyl (R)-2-acetamido-3-methoxypropionamides: potent anticonvulsants that affect frequency (use) dependence and slow inactivation of sodium channels.

    Science.gov (United States)

    Lee, Hyosung; Park, Ki Duk; Torregrosa, Robert; Yang, Xiao-Fang; Dustrude, Erik T; Wang, Yuying; Wilson, Sarah M; Barbosa, Cindy; Xiao, Yucheng; Cummins, Theodore R; Khanna, Rajesh; Kohn, Harold

    2014-07-24

    We prepared 13 derivatives of N-(biphenyl-4'-yl)methyl (R)-2-acetamido-3-methoxypropionamide that differed in type and placement of a R-substituent in the terminal aryl unit. We demonstrated that the R-substituent impacted the compound's whole animal and cellular pharmacological activities. In rodents, select compounds exhibited excellent anticonvulsant activities and protective indices (PI=TD50/ED50) that compared favorably with clinical antiseizure drugs. Compounds with a polar, aprotic R-substituent potently promoted Na+ channel slow inactivation and displayed frequency (use) inhibition of Na+ currents at low micromolar concentrations. The possible advantage of affecting these two pathways to decrease neurological hyperexcitability is discussed.

  5. 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.

  6. 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.

  7. Importance of passive diffusion in the uptake of polychlorinated biphenyls by phagotrophic protozoa

    Energy Technology Data Exchange (ETDEWEB)

    Kujawinski, E.B.; Farrington, J.W.; Moffett, J.W.

    2000-05-01

    Unicellular protozoan grazers represent a size class of organisms where a transition in the mechanism of chlorobiphenyl (CB) introduction, from diffusion through surface membranes to ingestion of contaminated prey, could occur. This study compares the relative importance of these two processes in the overall uptake of polychlorinated biphenyls by protists. Uptake rates and steady-state concentrations were compared in laboratory cultures of grazing and nongrazing protozoa. These experiments were conducted with a 10-{micro}m marine scuticociliate (Uronema sp.), bacterial prey (Halomonas halodurans), and a suite of 21 CB congeners spanning a range of aqueous solubilities. The dominant pathway of CB uptake by both grazing and nongrazing protozoa was diffusion. Organic-carbon-normalized CB concentrations (in the protozoan cell) were equivalent in grazing and nongrazing protozoa for all congeners studied. Rate constants for uptake into and loss from the protozoan cell were independently determined by using [3,3{prime}, 4,4{prime}-{sup 14}C]tetrachlorobiphenyl (IUPAC no. 77), 0.38 {+-} 0.03 min{sup {minus}1} and (1.1 {+-} 0.1) x 10{sup {minus}5} (g of organic carbon){minus}{sup {minus}1} min{sup {minus}1}, respectively. Magnitudes of the uptake and loss processes were calculated and compared by using a numerical model. The model result was consistent with data from the bioaccumulation experiment and supported the hypothesis that diffusive uptake is faster than ingestive uptake in phagotrophic unicellular protozoa.

  8. 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.

  9. Dehalogenation of Polybrominated Diphenyl Ethers and Polychlorinated Biphenyl by Bimetallic, Impregnated, and Nanoscale Zerovalent Iron

    Science.gov (United States)

    Zhuang, Yuan; Ahn, Sungwoo; Seyfferth, Angelia L.; Masue-Slowey, Yoko; Fendorf, Scott; Luthy, Richard G.

    2011-01-01

    Nanoscale zerovalent iron particles (nZVI), bimetallic nanoparticles (nZVI/Pd), and nZVI/Pd impregnated activated carbon (nZVI/Pd-AC) composite particles were synthesized and investigated for their effectiveness to remove polybrominated diphenyl ethers (PBDEs) and/or polychlorinated biphenyls (PCBs). Palladization of nZVI promoted the dehalogenation kinetics for mono- to tri-BDEs and 2,3,4-trichlorobiphenyl (PCB 21). Compared to nZVI, the iron-normalized rate constants for nZVI/Pd were about 2-, 3-, and 4-orders of magnitude greater for tri-, di-, and mono-BDEs, respectively, with diphenyl ether as a main reaction product. The reaction kinetics and pathways suggest an H-atom transfer mechanism. The reaction pathways with nZVI/Pd favor preferential removal of para-halogens on PBDEs and PCBs. X-ray fluorescence mapping of nZVI/Pd-AC showed that Pd mainly deposits on the outer part of particles, while Fe was present throughout the activated carbon particles. While BDE 21 was sorbed onto activated carbon composites quickly, debromination was slower compared to reaction with freely dispersed nZVI/Pd. Our XPS and chemical data suggest about 7% of the total iron within the activated carbon was zero-valent, which shows the difficulty with in-situ synthesis of a significant fraction of zero-valent iron in the micro-porous material. Related factors that likely hinder the reaction with nZVI/Pd-AC are the heterogenous distribution of nZVI and Pd on activated carbon and/or immobilization of hydrophobic organic contaminants at the adsorption sites thereby inhibiting contact with nZVI. PMID:21557574

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

    Science.gov (United States)

    Crinnion, Walter J

    2011-03-01

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

  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. 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.

  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 Preliminary results of the comparison of the electrochemical behavior of a thioether and biphenyl

    Science.gov (United States)

    Morales, W.; Jones, W. R.

    1983-01-01

    An electrochemical cell was constructed to explore the feasibility of using electrochemical techniques to simulate the tribochemistry of various substances. The electrochemical cell was used to study and compare the behavior of a thioether 1,3-bis(phenylthio) benzene and biphenyl. It is found that under controlled conditions biphenyl undergoes a reversible reduction to a radical anion whereas the thioether undergoes an irreversible reduction yielding several products. The results are discussed in relationship to boundary lubrication.

  16. 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

  17. 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

  18. 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

  19. 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...

  1. Position-specific isotope modeling of organic micropollutants transformation through different reaction pathways

    DEFF Research Database (Denmark)

    Jin, Biao; Rolle, Massimo

    2016-01-01

    The degradation of organic micropollutants occurs via different reaction pathways. Compound specific isotope analysis is a valuable tool to identify such degradation pathways in different environmental systems. We propose a mechanism-based modeling approach that provides a quantitative framework ...

  2. In situ and laboratory determined first-order degradation rate constants of specific organic compounds in an aerobic aquifer

    DEFF Research Database (Denmark)

    Nielsen, P.H.; Bjerg, P.L.; Nielsen, P.

    1996-01-01

    In situ microcosms (ISM) and laboratory batch microcosms (LBM) were used for determination of the first-order degradation rate constants of benzene, toluene, o-xylene, nitrobenzene, naphthalene, biphenyl, o- and p-dichlorobenzene, 1,1,1 -trichloroethane, tetrachlorometane, trichloroethene......, tetrachloroethene, phenol, o-cresol, 2,4- and 2,6-dichlorophenol, 4,6-o-dichlorocresol, and o- and p-nitrophenol in an aerobic aquifer, All aromatic hydrocarbons were degraded in ISM and LBM experiments. The phenolic hydrocarbons were ail degraded in ISM experiments, but some failed to degrade in LBM experiments....... Chlorinated aliphatic hydrocarbons were degraded neither in ISM nor LBM experiments. Degradation rate constants were determined by a model accounting for kinetic sorption (bicontinuum model), lag phases, and first-order degradation. With a few exceptions, lag phases were less than 2 weeks in both ISM and LBM...

  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. Exploring bacterial lignin degradation.

    Science.gov (United States)

    Brown, Margaret E; Chang, Michelle C Y

    2014-04-01

    Plant biomass represents a renewable carbon feedstock that could potentially be used to replace a significant level of petroleum-derived chemicals. One major challenge in its utilization is that the majority of this carbon is trapped in the recalcitrant structural polymers of the plant cell wall. Deconstruction of lignin is a key step in the processing of biomass to useful monomers but remains challenging. Microbial systems can provide molecular information on lignin depolymerization as they have evolved to break lignin down using metalloenzyme-dependent radical pathways. Both fungi and bacteria have been observed to metabolize lignin; however, their differential reactivity with this substrate indicates that they may utilize different chemical strategies for its breakdown. This review will discuss recent advances in studying bacterial lignin degradation as an approach to exploring greater diversity in the environment. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

    NARCIS (Netherlands)

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

    2006-01-01

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

  9. 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

  10. 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.

  11. 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.

  12. Organochlorine pesticides and polychlorinated biphenyls in California sea lions

    Energy Technology Data Exchange (ETDEWEB)

    Kannan, K.; Kajiwara, N.; Le Boeuf, B.J.; Tanabe, S

    2004-10-01

    Concentrations of polychlorinated biphenyls (PCBs), DDTs, chlordanes, HCHs, hexachlorobenzene (HCB), dieldrin, heptachlor epoxide, tris(4-chlorophenyl)methane (TCPMe), and tris(4-chlorophenyl)methanol (TCPMOH) were measured in the blubber of California sea lions (Zalophus californianus) collected in 2000. DDTs were the most predominant contaminants, followed by PCBs, chlordanes, TCPMe, HCHs, TCPMOH, dieldrin, and heptachlor epoxide. Concentrations of PCBs and DDTs varied from a few {mu}g/g to several hundreds of {mu}g/g on a lipid weight basis. Concentrations of DDTs have declined by an order of magnitude over the last three decades in California sea lions; nevertheless, the measured concentrations of PCBs and DDTs in California sea lions are still some of the highest values reported for marine mammals in recent years. Concentrations of organochlorines were highly correlated with one another. Concentrations of PCBs and DDTs in the blubber of gray whale, humpback whale, northern elephant seal, and harbor seal, and in the adipose fat of sea otter, were lower than the levels found in California sea lions, and were in the range of a few to several {mu}g/g on a lipid weight basis.

  13. Prenatal exposure to polychlorinated biphenyls: a neuropsychologic analysis.

    Science.gov (United States)

    Boucher, Olivier; Muckle, Gina; Bastien, Célyne H

    2009-01-01

    A large body of literature documents the effects of prenatal exposure to polychlorinated biphenyls (PCBs) on cognitive development of children. Despite this fact, no integrative synthesis has been published yet to identify the cognitive functions that are particularly affected. Our aim is to review this literature in an attempt to identify the cognitive profile associated with prenatal PCB exposure. Studies were identified by searching the PubMed database for articles published before June 2008. We reviewed data from nine prospective longitudinal birth cohorts for different aspects of cognition. Associations between indicators of prenatal PCB exposure and performance on cognitive tasks reported in the selected studies are summarized and classified as general cognitive abilities, verbal or visual-spatial skills, memory, attention, and executive functions. The most consistent effects observed across studies are impaired executive functioning related to increased prenatal PCB exposure. Negative effects on processing speed, verbal abilities, and visual recognition memory are also reported by most studies. Converging results from different cohort studies in which exposure arises from different sources make it unlikely that co-exposure with another associated contaminant is responsible for the observed effects. Prenatal PCB exposure appears to be related to a relatively specific cognitive profile of impairments. Failure to assess functions that are specifically impaired may explain the absence of effects found in some studies. Our findings have implications in the selection of cognitive assessment methods in future studies.

  14. 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.

  15. 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

  16. Remediation of PCB [polychlorinated biphenyl] -contaminated soils from scrapyards

    International Nuclear Information System (INIS)

    MacKnight, S.

    1991-01-01

    Much of the recent attention on contamination of the environment by polychlorinated biphenyls (PCB) has focused on liquid PCB spills from electrical equipment. A new, and possibly more serious, source of PCB contamination is the scrap yard, typically located in or near major urban centers, where the local scrap dealer would purchase used transformers or other PCB-containing electrical equipment, recover copper and other metals, and dump the PCB-containing oils on the ground. With the rising value of urban and suburban lands, these scrap yards may be slated for redevelopment, making the cleanup of contaminated soils necessary. The heterogeneous distribution of scrap yard contaminants requires a very detailed site assessment, and the heterogeneous mixture of typical scrap yard contaminants (not only PCB) cannot be treated in a simple fashion. These problems are illustrated for the case of the assessment and cleanup of a scrap yard site in Nova Scotia. A grid block system was used to sample soil at the site, and samples were analyzed for PCB, metals, and hydrocarbons. The most severely contaminated spots were mapped; groundwater patterns were also examined. The remediation process can be divided into 5 phases: physical separation of uncontaminated material; three stages of separation of materials into those having single, several-but-similar, and multicomponent mixed contaminations; and selection of appropriate process technologies. Since there is currently no approved PCB destruction facility in Atlantic Canada, excavated soils containing PCB are stored securely on the site to await approval for some type of incineration process

  17. Organochlorine pesticides and polychlorinated biphenyls in California sea lions

    International Nuclear Information System (INIS)

    Kannan, K.; Kajiwara, N.; Le Boeuf, B.J.; Tanabe, S.

    2004-01-01

    Concentrations of polychlorinated biphenyls (PCBs), DDTs, chlordanes, HCHs, hexachlorobenzene (HCB), dieldrin, heptachlor epoxide, tris(4-chlorophenyl)methane (TCPMe), and tris(4-chlorophenyl)methanol (TCPMOH) were measured in the blubber of California sea lions (Zalophus californianus) collected in 2000. DDTs were the most predominant contaminants, followed by PCBs, chlordanes, TCPMe, HCHs, TCPMOH, dieldrin, and heptachlor epoxide. Concentrations of PCBs and DDTs varied from a few μg/g to several hundreds of μg/g on a lipid weight basis. Concentrations of DDTs have declined by an order of magnitude over the last three decades in California sea lions; nevertheless, the measured concentrations of PCBs and DDTs in California sea lions are still some of the highest values reported for marine mammals in recent years. Concentrations of organochlorines were highly correlated with one another. Concentrations of PCBs and DDTs in the blubber of gray whale, humpback whale, northern elephant seal, and harbor seal, and in the adipose fat of sea otter, were lower than the levels found in California sea lions, and were in the range of a few to several μg/g on a lipid weight basis

  18. Activated carbon immobilizes residual polychlorinated biphenyls in weathered contaminated soil.

    Science.gov (United States)

    Langlois, Valérie S; Rutter, Allison; Zeeb, Barbara A

    2011-01-01

    Activated carbon (AC) has recently been shown to be effective in sequestering persistent organic pollutants (POPs) from aquatic sediments. Most studies have demonstrated significant reductions of POP concentrations in water and in aquatic organisms; however, limited data exist on the possibility of using AC to immobilize remaining POPs at terrestrial contaminated sites. Under greenhouse conditions, pumpkin ssp cv. Howden) were grown, and red wiggler worms () were exposed to an industrial contaminated soil containing a mixture of polychlorinated biphenyls (PCBs), i.e., Aroclors 1254 and 1260) treated with one of four concentrations of AC (0.2, 0.8, 3.1, and 12.5%) for 2 mo. The addition of AC to contaminated soils virtually eliminated the bioavailability of PCBs to the plant and invertebrate species. There were reductions in PCB concentrations of more than 67% in ssp and 95% in . These data suggest that AC could be included as part of comprehensive site closure strategy at PCB-contaminated sites. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  19. 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

  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. Degradation and mineralization of 2-chloro-, 3-chloro- and 4-chlorobiphenyl by a newly characterized natural bacterial strain isolated from an electrical transformer fluid-contaminated soil.

    Science.gov (United States)

    Ilori, Matthew O; Robinson, Gary K; Adebusoye, Sunday A

    2008-01-01

    A bacterium classified as Achromobacter xylosoxidans strain IR08 by phenotypic typing coupled with 16S rRNA gene analysis was isolated from a soil contaminated with electrical transformer fluid for over sixty years using Aroclor 1221 as an enrichment substrate. The substrate utilization profiles revealed that IR08 could grow on all three monochlorobiphenyls (CBs), 2,4'- and 4,4'-dichlorobiphenyl as well as 2-chlorobenzoate (2-CBA), 3-CBA, 4-CBA, and 2,3-dichlorobenzoate. Unusually, growth was poorly sustained on biphenyl and benzoate. In growth experiments, IR08 degraded all CBs (0.27 mmol/L) in less than 96 h with concomitant stoichiometric release of inorganic chloride and growth yields were 2-3 times higher than those observed on biphenyl. In contrast to most of the chlorobiphenyl-degrading strains described in the literature, which are reported to form CBA, no metabolite was identified in the culture broth by HPLC analysis. When co-incubated with respective CBs and biphenyl, strain IR08 preferentially utilized the chlorinated analogues in less than 96 h while it took another 264 h before 90% of the initially supplied biphenyl could be degraded. The promotion of co-metabolic transformation of halogenated substrates by the inclusion of their non-halogenated derivatives may not therefore, result in universal benefits.

  4. 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.

  5. 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.

  6. Association between polychlorinated biphenyls and Parkinson's disease neuropathology.

    Science.gov (United States)

    Hatcher-Martin, Jaime M; Gearing, Marla; Steenland, Kyle; Levey, Allan I; Miller, Gary W; Pennell, Kurt D

    2012-10-01

    Polychlorinated biphenyls (PCBs) are synthetic chemicals primarily used as coolants and insulators in electrical equipment. Although banned for several decades, PCBs continue to exist in the environment because of their long half-life, continued presence in items produced before the ban, and poor disposal practices. Epidemiological and experimental studies have identified exposure to PCBs as a potential risk factor for Parkinson's disease, perhaps more so in females. The objective of this work was to examine the association between PCB levels in post-mortem human brain tissue and the diagnosis of Parkinson's disease, as well as the degree of nigral depigmentation. We also sought to determine if this association was more significant when patients were stratified by sex. Post-mortem brain samples from control patients and those diagnosed with Parkinson's disease were obtained from the Emory University Brain Bank and from the Nun Study. Concentrations of eight prevalent PCB congeners were extracted from post-mortem brain tissue and analyzed using gas chromatography-mass spectrometry. PCB congeners 153 and 180 were significantly elevated in the brains of Parkinson's disease patients. When stratified by sex, the female Parkinson's disease group demonstrated significantly elevated concentrations of total PCBs and specifically congeners 138, 153, and 180 compared to controls, whereas PCB concentrations in males were not significantly different between control and Parkinson's disease groups. In a separate population of women (Nun Study) who had no clinical signs or symptoms of PD, elevated concentrations total PCB and congeners 138, 153 and 180 were also observed in post-mortem brain tissue exhibiting moderate nigral depigmentation compared to subjects with mild or no depigmentation. These quantitative data demonstrate an association between brain PCB levels and Parkinson's disease-related pathology. Furthermore, these data support epidemiological and laboratory studies

  7. Association between polychlorinated biphenyls and Parkinson’s disease neuropathology

    Science.gov (United States)

    Hatcher-Martin, Jaime M.; Gearing, Marla; Steenland, Kyle; Levey, Allan I.; Miller, Gary W.; Pennell, Kurt D.

    2012-01-01

    Polychlorinated biphenyls (PCBs) are synthetic chemicals primarily used as coolants and insulators in electrical equipment. Although banned for several decades, PCBs continue to exist in the environment because of their long half-life, continued presence in items produced before the ban, and poor disposal practices. Epidemiological and experimental studies have identified exposure to PCBs as a potential risk factor for Parkinson’s disease, perhaps more so in females. The objective of this work was to examine the association between PCB levels in post-mortem human brain tissue and the diagnosis of Parkinson’s disease, as well as the degree of nigral depigmentation. We also sought to determine if this association was more significant when patients were stratified by sex. Post-mortem brain samples from control patients and those diagnosed with Parkinson’s disease were obtained from the Emory University Brain Bank and from the Nun Study. Concentrations of eight prevalent PCB congeners were extracted from post-mortem brain tissue and analyzed using gas chromatography-mass spectrometry. PCB congeners 153 and 180 were significantly elevated in the brains of Parkinson’s disease patients. When stratified by sex, the female Parkinson’s disease group demonstrated significantly elevated concentrations of total PCBs and specifically congeners 138, 153, and 180 compared to controls, whereas PCB concentrations in males were not significantly different between control and Parkinson’s disease groups. In a separate population of women (Nun Study) who had no clinical signs or symptoms of PD, elevated concentrations total PCB and congeners 138, 153 and 180 were also observed in post-mortem brain tissue exhibiting moderate nigral depigmentation compared to subjects with mild or no depigmentation. These quantitative data demonstrate an association between brain PCB levels and Parkinson’s disease-related pathology. Furthermore, these data support epidemiological and

  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

    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.

  10. 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

    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......, and Hg were at levels of environmental concern. The sediment in the drinking water source area (DWSA) was threatened by heavy metals from other areas, and some fundamental solutions were proposed to protect the DWSA....

  11. 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....

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

    Directory of Open Access Journals (Sweden)

    Lorentz JÄNTSCHI

    2006-01-01

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

  13. 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.

  14. Associations of Pseudomonas species and forage grasses enhance degradation of chlorinated benzoic acids in soil

    Energy Technology Data Exchange (ETDEWEB)

    Siciliano, S. D.

    1998-12-01

    Using chlorinated benzoic acid (CBA) as a model compound, this study attempted to show that microorganisms and plants can be used as bioremediation agents to clean up contaminated soil sites in a cost effective and environmentally friendly manner. CBA was used because it is present in soils contaminated with polychlorinated biphenyls (PCBs), or chlorinated pesticides. Sixteen forage grasses were screened in combination with 12 bacterial inoculants for their ability to promote the degradation of CBA in soil. Five associations of plants and bacteria were found to degrade CBA to a greater extent than plants without bacterial inoculants. Bacterial inoculants were shown to stimulate CBA degradation by altering the microbial community present on the root surface and thereby increasing the ability of this community to degrade CBA.

  15. 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

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

    International Nuclear Information System (INIS)

    Spector, June T.; De Roos, Anneclaire J.; Ulrich, Cornelia M.; Sheppard, Lianne; Sjoedin, Andreas; Wener, Mark H.; Wood, Brent

    2014-01-01

    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

  17. 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

  18. 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.

  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. Identification of an enhancer element of class Pi glutathione S-transferase gene required for expression by a co-planar polychlorinated biphenyl.

    Science.gov (United States)

    Matsumoto, M; Imagawa, M; Aoki, Y

    1999-01-01

    3,3',4,4',5-Pentachlorobiphenyl (PenCB), one of the most toxic co-planar polychlorinated biphenyl congeners, specifically induces class Pi glutathione S-transferase (GSTP1) as well as cytochrome P-450 1A1 in primary cultured rat liver parenchymal cells [Aoki, Matsumoto and Suzuki (1993) FEBS Lett. 333, 114-118]. However, the 5'-flanking sequence of the GSTP1 gene does not contain a xenobiotic responsive element, to which arylhydrocarbon receptor binds. Using a chloramphenicol acetyltransferase assay we demonstrate here that the enhancer termed GSTP1 enhancer I (GPEI) is necessary for the stimulation by PenCB of GSTP1 gene expression in primary cultured rat liver parenchymal cells. GPEI is already known to contain a dyad of PMA responsive element-like elements oriented palindromically. It is suggested that a novel signal transduction pathway activated by PenCB contributes to the stimulation of GSTP1 expression. PMID:10051428

  1. 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.

  2. Evaluating the behavior of polychlorinated biphenyl compounds in Lake Superior using a dynamic multimedia model

    Science.gov (United States)

    Khan, T.; Perlinger, J. A.; Urban, N. R.

    2017-12-01

    Certain toxic, persistent, bioaccumulative, and semivolatile compounds known as atmosphere-surface exchangeable pollutants or ASEPs are emitted into the environment by primary sources, are transported, deposited to water surfaces, and can be later re-emitted causing the water to act as a secondary source. Polychlorinated biphenyl (PCB) compounds, a class of ASEPs, are of major concern in the Laurentian Great Lakes because of their historical use primarily as additives to oils and industrial fluids, and discharge from industrial sources. Following the ban on production in the U.S. in 1979, atmospheric concentrations of PCBs in the Lake Superior region decreased rapidly. Subsequently, PCB concentrations in the lake surface water also reached near equilibrium as the atmospheric levels of PCBs declined. However, previous studies on long-term PCB levels and trends in lake trout and walleye suggested that the initial rate of decline of PCB concentrations in fish has leveled off in Lake Superior. In this study, a dynamic multimedia flux model was developed with the objective to investigate the observed levelling off of PCB concentrations in Lake Superior fish. The model structure consists of two water layers (the epilimnion and the hypolimnion), and the surface mixed sediment layer, while atmospheric deposition is the primary external pathway of PCB inputs to the lake. The model was applied for different PCB congeners having a range of hydrophobicity and volatility. Using this model, we compare the long-term trends in predicted PCB concentrations in different environmental media with relevant available measurements for Lake Superior. We examine the seasonal depositional and exchange patterns, the relative importance of different process terms, and provide the most probable source of the current observed PCB levels in Lake Superior fish. In addition, we evaluate the role of current atmospheric PCB levels in sustaining the observed fish concentrations and appraise the need

  3. Omega-3 fatty acid oxidation products prevent vascular endothelial cell activation by coplanar polychlorinated biphenyls

    International Nuclear Information System (INIS)

    Majkova, Zuzana; Layne, Joseph; Sunkara, Manjula; Morris, Andrew J.; Toborek, Michal; Hennig, Bernhard

    2011-01-01

    Coplanar polychlorinated biphenyls (PCBs) may facilitate development of atherosclerosis by stimulating pro-inflammatory pathways in the vascular endothelium. Nutrition, including fish oil-derived long-chain omega-3 fatty acids, such as docosahexaenoic acid (DHA, 22:6ω-3), can reduce inflammation and thus the risk of atherosclerosis. We tested the hypothesis that cyclopentenone metabolites produced by oxidation of DHA can protect against PCB-induced endothelial cell dysfunction. Oxidized DHA (oxDHA) was prepared by incubation of the fatty acid with the free radical generator 2,2-azo-bis(2-amidinopropane) dihydrochloride (AAPH). Cellular pretreatment with oxDHA prevented production of superoxide induced by PCB77, and subsequent activation of nuclear factor-κB (NF-κB). A 4 /J 4 -neuroprostanes (NPs) were identified and quantitated using HPLC ESI tandem mass spectrometry. Levels of these NPs were markedly increased after DHA oxidation with AAPH. The protective actions of oxDHA were reversed by treatment with sodium borohydride (NaBH 4 ), which concurrently abrogated A 4 /J 4 -NP formation. Up-regulation of monocyte chemoattractant protein-1 (MCP-1) by PCB77 was markedly reduced by oxDHA, but not by un-oxidized DHA. These protective effects were proportional to the abundance of A 4 /J 4 NPs in the oxidized DHA sample. Treatment of cells with oxidized eicosapentaenoic acid (EPA, 20:5ω-3) also reduced MCP-1 expression, but less than oxDHA. Treatment with DHA-derived cyclopentenones also increased DNA binding of NF-E2-related factor-2 (Nrf2) and downstream expression of NAD(P)H:quinone oxidoreductase (NQO1), similarly to the Nrf-2 activator sulforaphane. Furthermore, sulforaphane prevented PCB77-induced MCP-1 expression, suggesting that activation of Nrf-2 mediates the observed protection against PCB77 toxicity. Our data implicate A 4 /J 4 -NPs as mediators of omega-3 fatty acid-mediated protection against the endothelial toxicity of coplanar PCBs.

  4. 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

  5. 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

  6. 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

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

    NARCIS (Netherlands)

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

    1994-01-01

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

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

    NARCIS (Netherlands)

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

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

  9. Predicting the bioaccumulation of polyaromatic hydrocarbons and polychlorinated biphenyls in benthic animals in sediments

    NARCIS (Netherlands)

    Tuikka, A. I.; Leppänen, M. T.; Akkanen, J.; Sormunen, A. J.; Leonards, P. E.G.; van Hattum, B.; van Vliet, L. A.; Brack, W.; Smedes, F.; Kukkonen, J. V.K.

    2016-01-01

    There were two main objectives in this study. The first was to compare the accuracy of different prediction methods for the chemical concentrations of polyaromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in the organism, based on the measured chemical concentrations existing in

  10. Effects of black carbon on bioturbination-induced benthic fluxes of polychlorinated biphenyls

    NARCIS (Netherlands)

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

    2011-01-01

    It is unknown whether carbonaceous geosorbents, such as black carbon (BC) affect bioturbation by benthic invertebrates, thereby possibly affecting sediment–water exchange of sediment-bound contaminants. Here, we assess the effects of oil soot on polychlorinated biphenyl (PCB) mass transfer from

  11. 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

  12. Induction of monooxygenation in rainbow trout by polybrominated biphenyls: a comparative study.

    Science.gov (United States)

    Elcombe, C R; Lech, J J

    1978-01-01

    Two commercial polychlorinated biphenyl mixtures (Aroclor 1254 and Aroclor 1242) and one polybrominated biphenyl mixture (FireMaster BP-6) were examined for their abilities to induce hepatic microsomal monooxygenation in rainbow trout (Salmo gairdneri). Pretreatment of rainbow trout with Aroclors 1254 and 1242 (150 mg/kg IP) resulted in an approximate 10-fold induction of arylhydrocarbon (benzo[a]pyrene) hydroxylation, ethoxycoumarin-O-deethylation and ethoxyresorufin-O-deethylation within 7 days after injection. These enzyme activities remained elevated above control values for at least 2-3 weeks. Administration of FireMaster BP-6 (150 mg/kg IP) also resulted in an induction of several monooxygenase activities. Arylhydrocarbon (benzo[a]pyrene) hydroxylation, ethoxycoumarin-O-deethylation and ethoxyresorufin-O-deethylation were increased by 6-, 3,- and 25-fold, respectively. Only the latter two activities remained elevated two weeks post-injection. Ethylmorphine-N-demethylation was unaffected by the polyhalogenated biphenyls. Significant increases in P-450 hemoprotein were not observed after pretreatment with any of the polyhalogenated biphenyls studied. PMID:209992

  13. 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...

  14. ANALYSIS OF SOIL AND DUST SAMPLES FOR POLYCHLORINATED BIPHENYLS BY ENZYME LINKED IMMUNOSORBENT ASSAY (ELISA)

    Science.gov (United States)

    An inhibition enzyme-linked immunosorbent assay (ELISA) was used to determine polychlorinated biphenyls (PCBs) in house dust and soil. Soil and house dust samples were analyzed for PCB by both gas chromatography/electron capture detection (GC/ECD) and ELISA methods. A correlati...

  15. [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.

  16. 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 bears * male reproduction Subject RIV: EH - Ecology, Behaviour Impact factor: 4.940, year: 2016

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

    DEFF Research Database (Denmark)

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

    2009-01-01

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

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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

  3. Bacterial degradation of monocyclic aromatic amines

    Directory of Open Access Journals (Sweden)

    Pankaj Kumar Arora

    2015-08-01

    Full Text Available Aromatic amines are an important group of industrial chemicals, which are widely used for manufacturing of dyes, pesticides, drugs, pigments, and other industrial products. These compounds have been considered highly toxic to human beings due to their carcinogenic nature. Three groups of aromatic amines have been recognized: monocyclic, polycyclic and heterocyclic aromatic amines. Bacterial degradation of several monocyclic aromatic compounds has been studied in a variety of bacteria, which utilizes monocyclic aromatic amines as their sole source of carbon and energy. Several degradation pathways have been proposed and the related enzymes and genes have also been characterized. Many reviews have been reviewed toxicity of monocyclic aromatic amines; however, there is lack of review on biodegradation of monocyclic aromatic amines. The aim of this review is to summarize bacterial degradation of monocyclic aromatic amines. This review will increase our current understanding of biochemical and molecular basis of bacterial degradation of monocyclic aromatic amines.

  4. Phytohormone and Light Regulation of Chlorophyll Degradation

    Directory of Open Access Journals (Sweden)

    Xiaoyu Zhu

    2017-11-01

    Full Text Available Degreening, due to the net loss of chlorophyll (Chl, is the most prominent symptom during the processes of leaf senescence, fruit ripening, and seed maturation. Over the last decade or so, extensive identifications of Chl catabolic genes (CCGs have led to the revelation of the biochemical pathway of Chl degradation. As such, exploration of the regulatory mechanism of the degreening process is greatly facilitated. During the past few years, substantial progress has been made in elucidating the regulation of Chl degradation, particularly via the mediation of major phytohormones' signaling. Intriguingly, ethylene and abscisic acid's signaling have been demonstrated to interweave with light signaling in mediating the regulation of Chl degradation. In this review, we briefly summarize this progress, with an effort on providing a framework for further investigation of multifaceted and hierarchical regulations of Chl degradation.

  5. Cometabolic Degradation of Dibenzofuran and Dibenzothiophene by a Naphthalene-Degrading Comamonas sp. JB.

    Science.gov (United States)

    Ji, Xiangyu; Xu, Jing; Ning, Shuxiang; Li, Nan; Tan, Liang; Shi, Shengnan

    2017-12-01

    Comamonas sp. JB was used to investigate the cometabolic degradation of dibenzofuran (DBF) and dibenzothiophene (DBT) with naphthalene as the primary substrate. Dehydrogenase and ATPase activity of the growing system with the presence of DBF and DBT were decreased when compared to only naphthalene in the growing system, indicating that the presence of DBF and DBT inhibited the metabolic activity of strain JB. The pathways and enzymes involved in the cometabolic degradation were tested. Examination of metabolites elucidated that strain JB cometabolically degraded DBF to 1,2-dihydroxydibenzofuran, subsequently to 2-hydroxy-4-(3'-oxo-3'H-benzofuran-2'-yliden)but-2-enoic acid, and finally to catechol. Meanwhile, strain JB cometabolically degraded DBT to 1,2-dihydroxydibenzothiophene and subsequently to the ring cleavage product. A series of naphthalene-degrading enzymes including naphthalene dioxygenase, 1,2-dihydroxynaphthalene dioxygenase, salicylaldehyde dehydrogenase, salicylate hydroxylase, and catechol 2,3-oxygenase have been detected, confirming that naphthalene was the real inducer of expression the degradation enzymes and metabolic pathways were controlled by naphthalene-degrading enzymes.

  6. 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

  7. 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...

  8. 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,...

  9. 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.

  10. Degradation of microbial polyesters.

    Science.gov (United States)

    Tokiwa, Yutaka; Calabia, Buenaventurada P

    2004-08-01

    Microbial polyhydroxyalkanoates (PHAs), one of the largest groups of thermoplastic polyesters are receiving much attention as biodegradable substitutes for non-degradable plastics. Poly(D-3-hydroxybutyrate) (PHB) is the most ubiquitous and most intensively studied PHA. Microorganisms degrading these polyesters are widely distributed in various environments. Although various PHB-degrading microorganisms and PHB depolymerases have been studied and characterized, there are still many groups of microorganisms and enzymes with varying properties awaiting various applications. Distributions of PHB-degrading microorganisms, factors affecting the biodegradability of PHB, and microbial and enzymatic degradation of PHB are discussed in this review. We also propose an application of a new isolated, thermophilic PHB-degrading microorganism, Streptomyces strain MG, for producing pure monomers of PHA and useful chemicals, including D-3-hydroxycarboxylic acids such as D-3-hydroxybutyric acid, by enzymatic degradation of PHB.

  11. Determination of vaporization enthalpies of polychlorinated biphenyls by correlation gas chromatography.

    Science.gov (United States)

    Puri, S; Chickos, J S; Welsh, W J

    2001-04-01

    The vaporization enthalpies of 16 polychlorinated biphenyls have been determined by correlation gas chromatography. This study was prompted by the realization that the vaporization enthalpy of the standard compounds used in previous studies, octadecane and eicosane, were values measured at 340 and 362 K, respectively, rather than at 298 K. Adjustment to 298 K amounts to a 7-8 kJ/mol increment in the values. With the inclusion of this adjustment, vaporization enthalpies evaluated by correlation gas chromatography are in good agreement with the values determined previously in the literature. The present results are based on the vaporization enthalpies of several standards whose values are well established in the literature. The standards include a variety of n-alkanes and various chlorinated hydrocarbons. The vaporization enthalpies of PCBs increased with the number of chlorine atoms and were found to be larger for meta- and para-substituted polychlorinated biphenyls.

  12. 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.

  13. 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.

  14. Photoionization and Electron Transfer of Biphenyl within the Channels of Al-ZSM-5 Zeolites.

    Science.gov (United States)

    Gener, Isabelle; Buntinx, Guy; Brémard, Claude

    1999-06-14

    Evidence of the photogenerated long-lived biphenyl radical and a trapped electron in the void space of aluminated nonacidic ZSM-5 zeolites has been obtained from the time-resolved UV/Vis absorption, Raman scattering, and EPR spectra. The restoration of the ground states implicates the existence of long-lived positive holes in the framework. © 1999 WILEY-VCH Verlag GmbH, Weinheim, Fed. Rep. of Germany.

  15. 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...

  16. Importance of Passive Diffusion in the Uptake of Polychlorinated Biphenyls by Phagotrophic Protozoa†

    OpenAIRE

    Kujawinski, Elizabeth B.; Farrington, John W.; Moffett, James W.

    2000-01-01

    Unicellular protozoan grazers represent a size class of organisms where a transition in the mechanism of chlorobiphenyl (CB) introduction, from diffusion through surface membranes to ingestion of contaminated prey, could occur. This study compares the relative importance of these two processes in the overall uptake of polychlorinated biphenyls by protists. Uptake rates and steady-state concentrations were compared in laboratory cultures of grazing and nongrazing protozoa. These experiments we...

  17. 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.

  18. 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

  19. 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

  20. 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.

  1. Molecular Pathways

    Science.gov (United States)

    Lok, Benjamin H.; Powell, Simon N.

    2012-01-01

    The Rad52 protein was largely ignored in humans and other mammals when the mouse knockout revealed a largely “no-effect” phenotype. However, using synthetic lethal approaches to investigate context dependent function, new studies have shown that Rad52 plays a key survival role in cells lacking the function of the BRCA1-BRCA2 pathway of homologous recombination. Biochemical studies also showed significant differences between yeast and human Rad52, in which yeast Rad52 can promote strand invasion of RPA-coated single-stranded DNA in the presence of Rad51, but human Rad52 cannot. This results in the paradox of how is human Rad52 providing Rad51 function: presumably there is something missing in the biochemical assays that exists in-vivo, but the nature of this missing factor is currently unknown. Recent studies have suggested that Rad52 provides back-up Rad51 function for all members of the BRCA1-BRCA2 pathway, suggesting that Rad52 may be a target for therapy in BRCA pathway deficient cancers. Screening for ways to inhibit Rad52 would potentially provide a complementary strategy for targeting BRCA-deficient cancers in addition to PARP inhibitors. PMID:23071261

  2. 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

  3. Intermittent degradation and schizotypy

    Directory of Open Access Journals (Sweden)

    Matthew W. Roché

    2015-06-01

    Full Text Available Intermittent degradation refers to transient detrimental disruptions in task performance. This phenomenon has been repeatedly observed in the performance data of patients with schizophrenia. Whether intermittent degradation is a feature of the liability for schizophrenia (i.e., schizotypy is an open question. Further, the specificity of intermittent degradation to schizotypy has yet to be investigated. To address these questions, 92 undergraduate participants completed a battery of self-report questionnaires assessing schizotypy and psychological state variables (e.g., anxiety, depression, and their reaction times were recorded as they did so. Intermittent degradation was defined as the number of times a subject’s reaction time for questionnaire items met or exceeded three standard deviations from his or her mean reaction time after controlling for each item’s information processing load. Intermittent degradation scores were correlated with questionnaire scores. Our results indicate that intermittent degradation is associated with total scores on measures of positive and disorganized schizotypy, but unrelated to total scores on measures of negative schizotypy and psychological state variables. Intermittent degradation is interpreted as potentially derivative of schizotypy and a candidate endophenotypic marker worthy of continued research.

  4. 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

  5. Cellular proteostasis: degradation of misfolded proteins by lysosomes

    Science.gov (United States)

    Jackson, Matthew P.

    2016-01-01

    Proteostasis refers to the regulation of the cellular concentration, folding, interactions and localization of each of the proteins that comprise the proteome. One essential element of proteostasis is the disposal of misfolded proteins by the cellular pathways of protein degradation. Lysosomes are an important site for the degradation of misfolded proteins, which are trafficked to this organelle by the pathways of macroautophagy, chaperone-mediated autophagy and endocytosis. Conversely, amyloid diseases represent a failure in proteostasis, in which proteins misfold, forming amyloid deposits that are not degraded effectively by cells. Amyloid may then exacerbate this failure by disrupting autophagy and lysosomal proteolysis. However, targeting the pathways that regulate autophagy and the biogenesis of lysosomes may present approaches that can rescue cells from the deleterious effects of amyloidogenic proteins. PMID:27744333

  6. Direct uptake and degradation of DNA by lysosomes

    Science.gov (United States)

    Fujiwara, Yuuki; Kikuchi, Hisae; Aizawa, Shu; Furuta, Akiko; Hatanaka, Yusuke; Konya, Chiho; Uchida, Kenko; Wada, Keiji; Kabuta, Tomohiro

    2013-01-01

    Lysosomes contain various hydrolases that can degrade proteins, lipids, nucleic acids and carbohydrates. We recently discovered “RNautophagy,” an autophagic pathway in which RNA is directly taken up by lysosomes and degraded. A lysosomal membrane protein, LAMP2C, a splice variant of LAMP2, binds to RNA and acts as a receptor for this pathway. In the present study, we show that DNA is also directly taken up by lysosomes and degraded. Like RNautophagy, this autophagic pathway, which we term “DNautophagy,” is dependent on ATP. The cytosolic sequence of LAMP2C also directly interacts with DNA, and LAMP2C functions as a receptor for DNautophagy, in addition to RNautophagy. Similarly to RNA, DNA binds to the cytosolic sequences of fly and nematode LAMP orthologs. Together with the findings of our previous study, our present findings suggest that RNautophagy and DNautophagy are evolutionarily conserved systems in Metazoa. PMID:23839276

  7. Detection of Surface-Linked Polychlorinated Biphenyls using Surface-Enhanced Raman Scattering Spectroscopy

    DEFF Research Database (Denmark)

    Rindzevicius, Tomas; Barten, Jan; Vorobiev, Mikhail

    2017-01-01

    We present an improved procedure for analytical detection of toxic polychlorinated biphenyls (PCB) using surface-enhanced Raman scattering (SERS) spectroscopy. A gold-capped silicon nanopillar substrate was utilized to concentrate PCB molecules within an area of high electromagnetic fields through...... formation of microsized nanopillar clusters, and consequently, so-called “hot spots” can be formed. In order to improve PCB detection limit, 3,3',4,4'-tetrachlorobiphenyl (PCB77) compounds were chemically modified with a – SCH3 (PCB77-SCH3) group. Experimental and numerical analysis of vibrational modes...

  8. Secondary sex ratio in relation to exposures to polychlorinated biphenyls, dichlorodiphenyl dichloroethylene and methylmercury

    DEFF Research Database (Denmark)

    Timmermann, Clara Amalie Gade; Choi, Anna L; Petersen, Maria Skaalum

    2017-01-01

    This study was undertaken to assess the potential impact of maternal exposures to polychlorinated biphenyl (PCB), dichlorodiphenyl dichloroethylene (DDE) and methylmercury on the secondary sex ratios (the ratio of male to female live births) over a span of 23 years. The study includes prospective......% CI = 2-17%), respectively, of giving birth to a boy. In conclusion, maternal exposure to ΣPCB, DDE and methylmercury was associated with a slightly increased secondary sex ratio. The impact of paternal exposures could not be taken into account and deserves attention....

  9. 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.

  10. 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.

  11. Electrodialytic remediation of polychlorinated biphenyls contaminated soil with iron nanoparticles and two different surfactants

    DEFF Research Database (Denmark)

    Gomes, Helena I.; Dias-Ferreira, Celia; Ottosen, Lisbeth M.

    2014-01-01

    Polychlorinated biphenyls (PCB) are persistent organic pollutants (POP) that strongly adsorb in soils and sediments. There is a need to develop new and cost-effective solutions for the remediation of PCB contaminated soils. The suspended electrodialytic remediation combined with zero valent iron......ZVI showed encouraging tendencies and a base is thus formed for further optimization towards a new method for remediation of PCB polluted soils....... nanoparticles (nZVI) could be a competitive alternative to the commonly adapted solutions of incineration or landfilling. Surfactants can enhance the PCB desorption, dechlorination, and the contaminated soil cleanup. In this work, two different surfactants (saponin and Tween 80) were tested to enhance PCB...

  12. Levels of polychlorinated biphenyls and pesticides in bluefish before and after cooking.

    Science.gov (United States)

    Trotter, W J; Corneliussen, P E; Laski, R R; Vannelli, J J

    1989-01-01

    Similar levels of polychlorinated biphenyls (PCBs), pesticides, and fat were found in 20 correlated uncooked and cooked (baked) bluefish fillets. Fillets averaged 2.5 ppm PCBs as Aroclor 1254 (whole basis) before cooking; after cooking, with the oil drippings and skin discarded, the average PCB level was 2.7 ppm. Although PCBs, lipophilic pesticides, and fat were lost along with oil drippings and skin that were discarded after cooking, the moisture loss in the fillets during cooking compensated for these weight losses almost completely. After the fillets were cooked and the oil drippings and skin were discarded, the PCB content of the fillets was 27% lower on the average.

  13. 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.

  14. 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

  15. Bacteria and lignin degradation

    Institute of Scientific and Technical Information of China (English)

    Jing LI; Hongli YUAN; Jinshui YANG

    2009-01-01

    Lignin is both the most abundant aromatic (phenolic) polymer and the second most abundant raw material.It is degraded and modified by bacteria in the natural world,and bacteria seem to play a leading role in decomposing lignin in aquatic ecosystems.Lignin-degrading bacteria approach the polymer by mechanisms such as tunneling,erosion,and cavitation.With the advantages of immense environmental adaptability and biochemical versatility,bacteria deserve to be studied for their ligninolytic potential.

  16. 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, ...

  17. 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....

  18. 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

  19. 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

  20. 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

  1. Enzymatic degradation of aliphatic nitriles by Rhodococcus rhodochrous BX2, a versatile nitrile-degrading bacterium.

    Science.gov (United States)

    Fang, Shumei; An, Xuejiao; Liu, Hongyuan; Cheng, Yi; Hou, Ning; Feng, Lu; Huang, Xinning; Li, Chunyan

    2015-06-01

    Nitriles are common environmental pollutants, and their removal has attracted increasing attention. Microbial degradation is considered to be the most acceptable method for removal. In this work, we investigated the biodegradation of three aliphatic nitriles (acetonitrile, acrylonitrile and crotononitrile) by Rhodococcus rhodochrous BX2 and the expression of their corresponding metabolic enzymes. This organism can utilize all three aliphatic nitriles as sole carbon and nitrogen sources, resulting in the complete degradation of these compounds. The degradation kinetics were described using a first-order model. The degradation efficiency was ranked according to t1/2 as follows: acetonitrile>trans-crotononitrile>acrylonitrile>cis-crotononitrile. Only ammonia accumulated following the three nitriles degradation, while amides and carboxylic acids were transient and disappeared by the end of the assay. mRNA expression and enzyme activity indicated that the tested aliphatic nitriles were degraded via both the inducible NHase/amidase and the constitutive nitrilase pathways, with the former most likely preferred. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Atmospheric polychlorinated biphenyls in Indian cities: Levels, emission sources and toxicity equivalents

    International Nuclear Information System (INIS)

    Chakraborty, Paromita; Zhang, Gan; Eckhardt, Sabine; Li, Jun; Breivik, Knut; Lam, Paul K.S.; Tanabe, Shinsuke; Jones, Kevin C.

    2013-01-01

    Atmospheric concentration of Polychlorinated biphenyls (PCBs) were measured on diurnal basis by active air sampling during Dec 2006 to Feb 2007 in seven major cities from the northern (New Delhi and Agra), eastern (Kolkata), western (Mumbai and Goa) and southern (Chennai and Bangalore) parts of India. Average concentration of Σ 25 PCBs in the Indian atmosphere was 4460 (±2200) pg/m −3 with a dominance of congeners with 4–7 chlorine atoms. Model results (HYSPLIT, FLEXPART) indicate that the source areas are likely confined to local or regional proximity. Results from the FLEXPART model show that existing emission inventories cannot explain the high concentrations observed for PCB-28. Electronic waste, ship breaking activities and dumped solid waste are attributed as the possible sources of PCBs in India. Σ 25 PCB concentrations for each city showed significant linear correlation with Toxicity equivalence (TEQ) and Neurotoxic equivalence (NEQ) values. Highlights: •Unlike decreasing trend of PCBs in United States and European countries, high levels of PCBs remain in the Indian atmosphere. •Existing emission inventories cannot explain the high PCB concentrations in Indian atmosphere. •Electronic waste recycling, ship dismantling and open burning of municipal solid waste are implicated as potential sources. -- Measurement of atmospheric Polychlorinated biphenyls in seven major Indian cities

  3. Net trophic transfer efficiencies of polychlorinated biphenyl congeners to lake trout (Salvelinus namaycush) from its prey

    Science.gov (United States)

    Madenjian, Charles P.; David, Solomon R.; Rediske, Richard R.; O’Keefe, James P.

    2012-01-01

    Lake trout (Salvelinus namaycush) were fed bloater (Coregonus hoyi) in eight laboratory tanks over a 135-d experiment. At the start of the experiment, four to nine fish in each tank were sacrificed, and the concentrations of 75 polychlorinated biphenyl (PCB) congeners within these fish were determined. Polychlorinated biphenyl congener concentrations were also determined in the 10 lake trout remaining in each of the eight tanks at the end of the experiment as well as in the bloater fed to the lake trout. Each lake trout was weighed at the start and the end of the experiment, and the amount of food eaten by the lake trout was recorded. Using these measurements, net trophic transfer efficiency (γ) from the bloater to the lake trout in each of the eight tanks was calculated for each of the 75 congeners. Results showed that γ did not vary significantly with the degree of chlorination of the PCB congeners, and γ averaged 0.66 across all congeners. However,γ did show a slight, but significant, decrease as logKOW increased from 6.0 to 8.2. Activity level of the lake trout did not have a significant effect on γ.

  4. 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.

  5. The associations between the environmental exposure to polychlorinated biphenyls (PCBs) and breast cancer risk and progression

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Polychlorinated biphenyls(PCBs) are chlorinated biphenyl compounds with wide applications in the industry.In spite of a ban on their production in the late 1970s,PCBs,as a group of POPs,are still persistent and widely spread in the environment,posing potential threats to human health.The role of PCBs as etiologic agents for breast cancer has been intensively explored in a variety of in vivo,animal and epidemiologic studies.Initial investigations indicated higher levels of PCBs in mammary tissues or sera corresponded to the occurrence of breast cancer,but later studies showed no positive association between PCB exposure and breast cancer development.More recent data suggested that the CYP1A1 m2 polymorphisms might add increased risk to the etiology of breast cancer in women with environmental exposure to PCBs.PCBs are implicated in advancing breast cancer progression,and our unpublished data reveals that PCBs activate the ROCK signaling to enhance breast cancer metastasis.Therefore,the correlation between PCB exposure and breast cancer risk warrants further careful investigations.

  6. Enhancing effect of spawning on elimination of a persistent polychlorinated biphenyl from female yellow perch

    International Nuclear Information System (INIS)

    Vodicnik, M.J.; Peterson, R.E.

    1985-01-01

    Distribution and elimination of 2,5,2',5'-tetrachloro[14C]biphenyl (4-CB) were studied for 6 months after exposing sexually mature female yellow perch to the compound in water and transferring them to flowing 4-CB-free water. Perch that were exposed in January spawned in May, and the study was terminated in June. During the first 41/2 months after exposure, the t1/2 for whole-body elimination was 22 weeks, primarily by elimination of 4-CB from the viscera and carcass. During spawning, enhanced elimination (t1/2 less than 0.7 weeks) was due to the voiding of eggs containing 4-CB. After spawning, whole-body elimination returned to a slower rate (t1/2 = 16.3 weeks). Prior to the enhancement in 4-CB elimination rate during spawning, there was a redistribution of 4-CB residues within the body of the perch which was characterized by a transfer of 4-CB residues from primarily the carcass and viscera to eggs. Two weeks after exposure, 30% of the initial 4-CB body burden was distributed to the eggs, whereas just prior to spawning, about 50% was present in this tissue. These findings demonstrate that egg maturation and spawning result in a significant reduction in the body burden of a persistent polychlorinated biphenyl in a lean-fish species

  7. Polychlorinated biphenyls in surface soil in urban and background areas of Mongolia

    International Nuclear Information System (INIS)

    Mamontova, Elena A.; Mamontov, Alexander A.; Tarasova, Eugenia N.; Kuzmin, Mikhail I.; Ganchimeg, Darmaa; Khomutova, Marina Yu.; Gombosuren, Odontuya; Ganjuurjav, Erdenebayasgalan

    2013-01-01

    Polychlorinated biphenyls (PCBs) were measured in soil in some industrial towns (Ulaanbaatar, Suhbaatar, Erdenet, Darhan, Tsetserleg, Hovd, Ulaangom, Altay, Bayanhongor, Arvayheer, Saynshand, Choybalsan) and in background and rural areas of Mongolia. The average sum of all investigated PCB congeners in soil of Mongolia comes to 7.4 ng/g dry weight (DW) and varies from 0.53 ng/g DW till 114 ng/g DW. PCB levels in soil from towns are significantly higher than those in soil from background and rural areas. The PCB homological composition in soil sampled in highly-PCB-polluted sites is similar to the PCB homological pattern in Sovol and Aroclor 1254. Significant correlation between soil organic carbon and low chlorinated PCB both for towns and background sites was found. Significant differences in PCB means in soil in different natural zones were found. -- Highlights: •First study to measure PCBs in surface soil sampled throughout Mongolia. •The PCB patterns in polluted soil were similar to those in Sovol or Aroclor 1254. •Significant differences in PCB means in soil in different natural zones were found. -- Polychlorinated biphenyls were measured in soils throughout Mongolia

  8. Design, Synthesis, and Herbicidal Activity of Pyrimidine-Biphenyl Hybrids as Novel Acetohydroxyacid Synthase Inhibitors.

    Science.gov (United States)

    Li, Ke-Jian; Qu, Ren-Yu; Liu, Yu-Chao; Yang, Jing-Fang; Devendar, Ponnam; Chen, Qiong; Niu, Cong-Wei; Xi, Zhen; Yang, Guang-Fu

    2018-04-18

    The issue of weed resistance to acetohydroxyacid synthase (EC 2.2.1.6, AHAS) inhibitors has become one of the largest obstacles for the application of this class of herbicides. In a continuing effort to discover novel AHAS inhibitors to overcome weed resistance, a series of pyrimidine-biphenyl hybrids (4aa-bb and 5aa-ah) were designed and synthesized via a scaffold hopping strategy. Among these derivatives, compounds 4aa ( K i = 0.09 μM) and 4bb ( K i = 0.02 μM) displayed higher inhibitory activities against Arabidopsis thaliana AHAS than those of the controls bispyribac ( K i = 0.54 μM) and flumetsulam ( K i = 0.38 μM). Remarkably, compounds 4aa, 4bb, 5ah, and 5ag exhibited excellent postemergence herbicidal activity and a broad spectrum of weed control at application rates of 37.5-150 g of active ingredient (ai)/ha. Furthermore, 4aa and 4bb showed higher herbicidal activity against AHAS inhibitor-resistant Descurainia sophia, Ammannia arenaria, and the corresponding sensitive weeds than that of bispyribac at 0.94-0.235 g ai/ha. Therefore, the pyrimidine-biphenyl motif and lead compounds 4aa and 4bb have great potential for the discovery of novel AHAS inhibitors to combat AHAS-inhibiting herbicide-resistant weeds.

  9. 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.

  10. 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.

  11. 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

  12. 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

  13. 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.

  14. Mechanism and kinetics of parathion degradation under ultrasonic irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yao Juanjuan, E-mail: yao_juanjuan@yahoo.cn [State Key laboratory of Pollution Control and Resources Reuse, Tongji University, Shanghai, 200092 (China); Gao Naiyun; Li Cong; Li Lei; Xu Bin [State Key laboratory of Pollution Control and Resources Reuse, Tongji University, Shanghai, 200092 (China)

    2010-03-15

    The parathion degradation under ultrasonic irradiation in aqueous solution was investigated. The results indicate that at the conditions in question, degradation rate of parathion decreased with increasing initial concentration and decreasing power. The optimal frequency for parathion degradation was 600 kHz. The free radical reactions predominate in the sonochemical degradation of parathion and the reaction zones are predominately at the bubble interface and, to a much lesser extent, in bulk solution. The gas/liquid interfacial regions are the real effective reaction sites for sonochemical degradation of parathion. The reaction can be well described as a gas/liquid heterogeneous reaction which obeys a kinetic model based on Langmuir-Hinshelwood model. The main pathways of parathion degradation by ultrasonic irradiation were also proposed by qualitative and quantitative analysis of organic and inorganic byproducts. It is indicated that the N{sub 2} in air takes part in the parathion degradation through the formation of {center_dot}NO{sub 2} under ultrasonic irradiation. Parathion is decomposed into paraoxon and 4-nitrophenol in the first step via two different pathways, respectively, which is in agreement with the theoretical molecular orbital (MO) calculations.

  15. Modularized Smad-regulated TGFβ signaling pathway.

    Science.gov (United States)

    Li, Yongfeng; Wang, Minli; Carra, Claudio; Cucinotta, Francis A

    2012-12-01

    The transforming Growth Factor β (TGFβ) signaling pathway is a prominent regulatory signaling pathway controlling various important cellular processes. TGFβ signaling can be induced by several factors including ionizing radiation. The pathway is regulated in a negative feedback loop through promoting the nuclear import of the regulatory Smads and a subsequent expression of inhibitory Smad7, that forms ubiquitin ligase with Smurf2, targeting active TGFβ receptors for degradation. In this work, we proposed a mathematical model to study the Smad-regulated TGFβ signaling pathway. By modularization, we are able to analyze mathematically each component subsystem and recover the nonlinear dynamics of the entire network system. Meanwhile the excitability, a common feature observed in the biological systems, in the TGFβ signaling pathway is discussed and supported as well by numerical simulation, indicating the robustness of the model. Published by Elsevier Inc.

  16. Developments in polymer degradation - 7

    International Nuclear Information System (INIS)

    Grassie, N.

    1987-01-01

    A selection of topics which are representative of the continually expanding area of polymer degradation is presented. The aspects emphasised include the products of degradation of specific polymers, degradation by high energy radiation and mechanical forces, fire retardant studies and the special role of small radicals in degradation processes. (author)

  17. 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

  18. The different roles of selective autophagic protein degradation in mammalian cells.

    Science.gov (United States)

    Wang, Da-wei; Peng, Zhen-ju; Ren, Guang-fang; Wang, Guang-xin

    2015-11-10

    Autophagy is an intracellular pathway for bulk protein degradation and the removal of damaged organelles by lysosomes. Autophagy was previously thought to be unselective; however, studies have increasingly confirmed that autophagy-mediated protein degradation is highly regulated. Abnormal autophagic protein degradation has been associated with multiple human diseases such as cancer, neurological disability and cardiovascular disease; therefore, further elucidation of protein degradation by autophagy may be beneficial for protein-based clinical therapies. Macroautophagy and chaperone-mediated autophagy (CMA) can both participate in selective protein degradation in mammalian cells, but the process is quite different in each case. Here, we summarize the various types of macroautophagy and CMA involved in determining protein degradation. For this summary, we divide the autophagic protein degradation pathways into four categories: the post-translational modification dependent and independent CMA pathways and the ubiquitin dependent and independent macroautophagy pathways, and describe how some non-canonical pathways and modifications such as phosphorylation, acetylation and arginylation can influence protein degradation by the autophagy lysosome system (ALS). Finally, we comment on why autophagy can serve as either diagnostics or therapeutic targets in different human diseases.

  19. 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.

  20. Endocytic collagen degradation

    DEFF Research Database (Denmark)

    Madsen, Daniel H.; Jürgensen, Henrik J.; Ingvarsen, Signe Ziir

    2012-01-01

    it crucially important to understand both the collagen synthesis and turnover mechanisms in this condition. Here we show that the endocytic collagen receptor, uPARAP/Endo180, is a major determinant in governing the balance between collagen deposition and degradation. Cirrhotic human livers displayed a marked...... up-regulation of uPARAP/Endo180 in activated fibroblasts and hepatic stellate cells located close to the collagen deposits. In a hepatic stellate cell line, uPARAP/Endo180 was shown to be active in, and required for, the uptake and intracellular degradation of collagen. To evaluate the functional...... groups of mice clearly revealed a fibrosis protective role of uPARAP/Endo180. This effect appeared to directly reflect the activity of the collagen receptor, since no compensatory events were noted when comparing the mRNA expression profiles of the two groups of mice in an array system focused on matrix-degrading...

  1. 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...... in the atmosphere to yield a homologous series of PFCAs. Atmospheric degradation of FTOHs is likely to contribute to the widespread dissemination of PFCAs. After their bioaccumulation potential is accounted for, the pattern of PFCAs yielded from FTOHs could account for the distinct contamination profile of PFCAs....... The significance of the gas-phase peroxy radical cross reactions that produce PFCAs has not been recognized previously. Such reactions are expected to occur during the atmospheric degradation of all polyfluorinated materials, necessitating a reexamination of the environmental fate and impact of this important...

  2. 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

  3. 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)

  4. 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.)

  5. An egg injection technique to evaluate the effect of polychlorinated biphenyls on the hatching success of the snapping turtle (Chelydra serpentina serpentina).

    Science.gov (United States)

    Schnars, Jeanette L; Voss, Margaret A; Stauffer, Jay R

    2011-04-01

    Embryos of oviparous organisms are exposed to contaminants by two pathways: contaminant uptake from the surrounding environment, and the transfer from female to offspring (maternal transfer). The initial source of contaminant exposure for most embryos is likely to be maternal transfer; therefore, maternal transfer studies are critical in determining the effects of contaminants on future populations. Injection of contaminants directly into eggs is one route of experimental contaminant exposure that permits controlled doses and potential reliable replication. This technique, however, has been used in the past with little success in reptiles. The objective of the present study was to evaluate egg injection as a means of mimicking maternal transfer of polychlorinated biphenyls (PCBs) to snapping turtle eggs. Eggs from several clutches were injected with a PCB solution and incubated at several temperatures and moisture levels to measure interactive effects of injection, environmental condition, and contaminant load on hatching success. The injection technique allowed for application of consistent and specific doses among replicates. Overall hatching success in this study was 61% and was as high as 71% within specific treatments. Hatching success was much higher in this study than in other studies using egg injections to mimic maternal transfer in chelonians and crocodilians. Copyright © 2010 SETAC.

  6. 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

  7. 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.

  8. Detection of pump degradation

    International Nuclear Information System (INIS)

    Casada, D.A.

    1994-01-01

    There are a variety of stressors that can affect the operation of centrifugal pumps. These can generally be classified as: Mechanical; Hydraulic; Tribological; Chemical; and Other (including those associated with the pump driver). Although these general stressors are active in essentially all centrifugal pumps, the stressor level and the extent of wear and degradation can vary greatly. Parameters that affect the extent of stressor activity are manifold. In order to assure the long-term operational readiness of a pump, it is important to both understand the nature and magnitude of the specific degradation mechanisms and to monitor the performance of the pump

  9. Determination of levels of polychlorinated biphenyls (PCBs) present in caulk and window glazing material samples from older buildings

    Science.gov (United States)

    Levels of polychlorinated biphenyls (PCBs) in caulk and window glazing material samples from older buildings were determined, using a method developed for this purpose. This method was evaluated by analyzing a combination of 47 samples of caulk, glazing materials, including quali...

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

    DEFF Research Database (Denmark)

    Mehrtens, G.; Laturnus, F.

    1999-01-01

    Mixed function oxidase (MFO) dependent biotransformation of polychlorinated biphenyls (PCBs) was measured in three different fish species from the North Sea. Liver microsomes of plaice (Pleuronectes platessa), dab (Limanda limanda) and cod (Gadus morhua) were isolated and incubated with different....... Biotransformations were also species dependent. The flatfish dab and plaice exhibited higher metabolic rates than cod (C) 1999 Elsevier Science Ltd. All rights reserved....

  11. Hydrogen–Hydrogen Bonding in Planar Biphenyl, Predicted by Atoms-In-Molecules Theory, Does Not Exist

    NARCIS (Netherlands)

    Poater, J; Sola, M.; Bickelhaupt, F.M.

    2006-01-01

    Based on an Atoms-in-Molecules (AIM) analysis, Matta et al. (Chem. Eur. J.2003, 9, 1940) recently claimed evidence for the existence of hydrogen–hydrogen bonding between ortho-hydrogen atoms, pointing towards each other from adjacent phenyl groups in planar biphenyl. This AIM result is opposed to

  12. Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and biphenyls (PCBs) in home-produced eggs

    NARCIS (Netherlands)

    Hoogenboom, L.A.P.; Dam, ten G.; Bruggen, van Mark; Jeurissen, Suzanne; Leeuwen, van S.P.J.; Theelen, R.M.C.; Zeilmaker, M.J.

    2016-01-01

    Home produced eggs from 62 addresses in the Netherlands were investigated for the levels of polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs) and biphenyls (PCBs), both dioxin-like (dl) and non-dioxin-like (ndl). Compared to commercial eggs, levels were relatively high with a median of 4.6

  13. A SIMPLE AND FAST EXTRACTION METHOD FOR ORGANOCHLORINE PESTICIDES AND POLYCHLORINATED BIPHENYLS IN SMALL VOLUMES OF AVIAN SERUM

    Science.gov (United States)

    A solid-phase extraction (SPE) method was developed using 8 M urea to desorb and extract organochlorine pesticides (OCs) and polychlorinated biphenyls (PCBs) from avian serum for analysis by capillary gas chromatography with electron capture detection (GC-ECD). The analytes were ...

  14. Serum concentrations of polybrominated diphenyl ethers (PBDEs) and a polybrominated biphenyl (PBB) in men from Greenland, Poland and Ukraine

    DEFF Research Database (Denmark)

    Lenters, Virissa; Thomsen, Cathrine; Smit, Lidwien A M

    2013-01-01

    in Inuit men from across Greenland, and in men from Warsaw, Poland and Kharkiv, Ukraine. Serum was sampled between 2002 and 2004 from men 19 to 50years of age. 299 samples were analyzed for BDE-28, 47, 99, 100, 153, 154 and 183 and the brominated biphenyl BB-153 using gas chromatography-high resolution...

  15. 21 CFR 509.15 - Use of polychlorinated biphenyls (PCB's) in establishments manufacturing food-packaging materials.

    Science.gov (United States)

    2010-04-01

    ... establishments manufacturing food-packaging materials. 509.15 Section 509.15 Food and Drugs FOOD AND DRUG... polychlorinated biphenyls (PCB's) in establishments manufacturing food-packaging materials. (a) Polychlorinated...). These accidents in turn caused the contamination of food products intended for human consumption (meat...

  16. 21 CFR 109.15 - Use of polychlorinated biphenyls (PCB's) in establishments manufacturing food-packaging materials.

    Science.gov (United States)

    2010-04-01

    ... establishments manufacturing food-packaging materials. 109.15 Section 109.15 Food and Drugs FOOD AND DRUG... polychlorinated biphenyls (PCB's) in establishments manufacturing food-packaging materials. (a) Polychlorinated...). These accidents in turn caused the contamination of food products intended for human consumption (meat...