The Experts below are selected from a list of 12447 Experts worldwide ranked by ideXlab platform

L. Pompstra - One of the best experts on this subject based on the ideXlab platform.

  • Microbial dechlorination of Hexachlorobenzene in a sedimentation area of the Rhine River
    Biogeochemistry, 1993
    Co-Authors: J. E. M. Beurskens, C. G. C. Dekker, J. Jonkhoff, L. Pompstra
    Abstract:

    In sedimentation areas of polluted rivers, microbial dechlorination of chlorinated aromatics may be of great environmental significance. This reaction may take place in the deeper, anaerobic sediment layers and involves replacement of a chlorine in the pollutant molecule by hydrogen. In this study, the microbial dechlorination of Hexachlorobenzene in a sedimentation area of the Rhine River is evaluated by using Rhine water pollution data, concentrations in historical sediment samples and in recent sediment cores, and the results of anaerobic laboratory incubations with Lake Ketelmeer sediment. The various data support the conclusion that microbial dechlorination of Hexachlorobenzene has occurred in the anaerobic sediment. Up to 80% of the Hexachlorobenzene deposited in the early 1970s has been dechlorinated. The maximum half-life of Hexachlorobenzene in the sediment is found to be 7 years.

  • Microbial dechlorination of Hexachlorobenzene in a sedimentation area of the Rhine River
    Biogeochemistry, 1992
    Co-Authors: J. E. M. Beurskens, C. G. C. Dekker, J. Jonkhoff, L. Pompstra
    Abstract:

    In sedimentation areas of polluted rivers, microbial dechlorination of chlorinated aromatics may be of great environmental significance. This reaction may take place in the deeper, anaerobic sediment layers and involves replacement of a chlorine in the pollutant molecule by hydrogen. In this study, the microbial dechlorination of Hexachlorobenzene in a sedimentation area of the Rhine River is evaluated by using Rhine water pollution data, concentrations in historical sediment samples and in recent sediment cores, and the results of anaerobic laboratory incubations with Lake Ketelmeer sediment. The various data support the conclusion that microbial dechlorination of Hexachlorobenzene has occurred in the anaerobic sediment. Up to 80% of the Hexachlorobenzene deposited in the early 1970s has been dechlorinated. The maximum half-life of Hexachlorobenzene in the sediment is found to be 7 years. Two limitations of microbially mediated dechlorination in the natural environment have become clear. In the first place, a residual concentration of about 40 μg/kg remains unaltered in the sediment or transformation rates of this fraction are at least extremely low. Secondly, the lower chlorinated benzenes that are produced from Hexachlorobenzene appear to accumulate in the anaerobic sediment.

J. E. M. Beurskens - One of the best experts on this subject based on the ideXlab platform.

  • Microbial dechlorination of Hexachlorobenzene in a sedimentation area of the Rhine River
    Biogeochemistry, 1993
    Co-Authors: J. E. M. Beurskens, C. G. C. Dekker, J. Jonkhoff, L. Pompstra
    Abstract:

    In sedimentation areas of polluted rivers, microbial dechlorination of chlorinated aromatics may be of great environmental significance. This reaction may take place in the deeper, anaerobic sediment layers and involves replacement of a chlorine in the pollutant molecule by hydrogen. In this study, the microbial dechlorination of Hexachlorobenzene in a sedimentation area of the Rhine River is evaluated by using Rhine water pollution data, concentrations in historical sediment samples and in recent sediment cores, and the results of anaerobic laboratory incubations with Lake Ketelmeer sediment. The various data support the conclusion that microbial dechlorination of Hexachlorobenzene has occurred in the anaerobic sediment. Up to 80% of the Hexachlorobenzene deposited in the early 1970s has been dechlorinated. The maximum half-life of Hexachlorobenzene in the sediment is found to be 7 years.

  • Microbial dechlorination of Hexachlorobenzene in a sedimentation area of the Rhine River
    Biogeochemistry, 1992
    Co-Authors: J. E. M. Beurskens, C. G. C. Dekker, J. Jonkhoff, L. Pompstra
    Abstract:

    In sedimentation areas of polluted rivers, microbial dechlorination of chlorinated aromatics may be of great environmental significance. This reaction may take place in the deeper, anaerobic sediment layers and involves replacement of a chlorine in the pollutant molecule by hydrogen. In this study, the microbial dechlorination of Hexachlorobenzene in a sedimentation area of the Rhine River is evaluated by using Rhine water pollution data, concentrations in historical sediment samples and in recent sediment cores, and the results of anaerobic laboratory incubations with Lake Ketelmeer sediment. The various data support the conclusion that microbial dechlorination of Hexachlorobenzene has occurred in the anaerobic sediment. Up to 80% of the Hexachlorobenzene deposited in the early 1970s has been dechlorinated. The maximum half-life of Hexachlorobenzene in the sediment is found to be 7 years. Two limitations of microbially mediated dechlorination in the natural environment have become clear. In the first place, a residual concentration of about 40 μg/kg remains unaltered in the sediment or transformation rates of this fraction are at least extremely low. Secondly, the lower chlorinated benzenes that are produced from Hexachlorobenzene appear to accumulate in the anaerobic sediment.

Peter D. Siersema - One of the best experts on this subject based on the ideXlab platform.

  • Ferritin accumulation and uroporphyrin crystal formation in hepatocytes of C57BL/10 mice: a time-course study
    Cell and Tissue Research, 1993
    Co-Authors: Peter D. Siersema, Maud I. Cleton-soeteman, Wim C. Bruijn, Fiebo J. W. Kate, Henk G. Eijk, J. H. Paul Wilson
    Abstract:

    To establish the time-sequence relationship between ferritin accumulation and uroporphyrin crystal formation in livers of C57BL/10 mice, a biochemical, morphological and morphometrical study was performed. Uroporphyria was induced by the intraperitoneal administration of Hexachlorobenzene plus iron dextran and of iron dextran alone. Uroporphyrin crystal formation started in hepatocytes of mice treated with Hexachlorobenzene plus iron dextran at 2 weeks and in mice treated with iron dextran alone at 9 weeks. In the course of time, uroporphyrin crystals gradually increased in size. Uroporphyrin crystals were initially formed in hepatocytes in the periportal areas of the liver, in which also ferric iron staining was first detected. The amount and the distribution of the main storage form of iron in hepatocytes, ferritin, did not differ between the two treatment groups. Ferritin accumulation preceded the formation of uroporphyrin crystals in hepatocytes in both treatment groups. Moreover, uroporphyrin crystals were nearly always found close to ferritin iron. We conclude that uroporphyrin crystals are only formed in hepatocytes in which also iron (ferritin) accumulates. Hexachlorobenzene accelerates the effects of iron in porphyrin metabolism, but does not influence the accumulation of iron into the liver.

  • ferritin accumulation and uroporphyrin crystal formation in hepatocytes of c57bl 10 mice a time course study
    Cell and Tissue Research, 1993
    Co-Authors: Peter D. Siersema, Wim C. Bruijn, Maud I Cletonsoeteman, Fiebo Ten J W Kate, Henk G Van Eijk, J Paul H Wilson
    Abstract:

    To establish the time-sequence relationship between ferritin accumulation and uroporphyrin crystal formation in livers of C57BL/10 mice, a biochemical, morphological and morphometrical study was performed. Uroporphyria was induced by the intraperitoneal administration of Hexachlorobenzene plus iron dextran and of iron dextran alone. Uroporphyrin crystal formation started in hepatocytes of mice treated with Hexachlorobenzene plus iron dextran at 2 weeks and in mice treated with iron dextran alone at 9 weeks. In the course of time, uroporphyrin crystals gradually increased in size. Uroporphyrin crystals were initially formed in hepatocytes in the periportal areas of the liver, in which also ferric iron staining was first detected. The amount and the distribution of the main storage form of iron in hepatocytes, ferritin, did not differ between the two treatment groups. Ferritin accumulation preceded the formation of uroporphyrin crystals in hepatocytes in both treatment groups. Moreover, uroporphyrin crystals were nearly always found close to ferritin iron. We conclude that uroporphyrin crystals are only formed in hepatocytes in which also iron (ferritin) accumulates. Hexachlorobenzene accelerates the effects of iron in porphyrin metabolism, but does not influence the accumulation of iron into the liver.

  • Iron and uroporphyrin in hepatocytes of inbred mice in experimental porphyria : a biochemical and morphological study
    Hepatology (Baltimore Md.), 1991
    Co-Authors: Peter D. Siersema, Wim C. Bruijn, J. H. Paul Wilson, René P. Van Helvoirt, Diane A. M. Ketelaars, Maud I. Cleton, Henk G Van Eijk
    Abstract:

    Hexachlorobenzene-induced porphyria is iron dependent and characterized by the decreased activity of uroporphyrinogen decarboxylase and the accumulation of porphyrins in the liver. To examine the relationship between iron and porphyrins in liver tissue, we performed a biochemical and morphological (histological, ultrastructural and morphometrical) study in the livers of C57BL/10 mice. Mice were treated with Hexachlorobenzene, iron dextran or the combination of Hexachlorobenzene and iron dextran. An accumulation of porphyrins and an increased total iron content were found not only in the livers of mice treated with Hexachlorobenzene and iron dextran but also in mice treated with iron dextran alone. In contrast, the amount of porphyrins was only slightly increased in the livers of mice treated with Hexachlorobenzene alone. Needle-like structures, representing uroporphyrin crystals, were observed, histologically and ultrastructurally, in hepatocytes of mice treated with Hexachlorobenzene and iron dextran and with iron dextran alone. Uroporphyrin crystals and ferritin iron were found in the same hepatocyte. A single uroporphyrin crystal, surrounded by ferritin iron, was observed in a hepatocyte of a mouse treated with Hexachlorobenzene alone. Both in the livers of mice treated with Hexachlorobenzene and iron dextran and in the livers of mice treated with iron dextran alone, morphometrical analysis showed that an increased area fraction of uroporphyrin crystals was associated with an increased area fraction of ferritin iron in hepatocytes. Conclusions: In C57BL/10 mice, experimental porphyria can be induced by iron overload alone; uroporphyrin crystals and ferritin iron are located in the same hepatocyte; and the morphological co-occurrence of uroporphyrin crystals and ferritin iron in hepatocytes suggests a role for iron (as ferritin) in the pathogenesis of porphyria. (HEPATOLOGY 1991;14:1179–1188.)

Lorenz Adrian - One of the best experts on this subject based on the ideXlab platform.

  • Table_3_Syntrophic Partners Enhance Growth and Respiratory Dehalogenation of Hexachlorobenzene by Dehalococcoides mccartyi Strain CBDB1.XLSX
    2018
    Co-Authors: Anh T. T. Chau, Lorenz Adrian, Matthew Lee, Michael J. Manefield
    Abstract:

    This study investigated syntrophic interactions between chlorinated benzene respiring Dehalococcoides mccartyi strain CBDB1 and fermenting partners (Desulfovibrio vulgaris, Syntrophobacter fumaroxidans, and Geobacter lovleyi) during Hexachlorobenzene respiration. Dechlorination rates in syntrophic co-cultures were enhanced 2-3 fold compared to H2 fed CBDB1 pure cultures (0.23 ± 0.04 μmol Cl− day−1). Syntrophic partners were also able to supply cobalamins to CBDB1, albeit with 3–10 fold lower resultant dechlorination activity compared to cultures receiving exogenous cyanocobalamin. Strain CBDB1 pure cultures accumulated ~1 μmol of carbon monoxide per 87.5 μmol Cl− released during Hexachlorobenzene respiration resulting in decreases in dechlorination activity. The syntrophic partners investigated were shown to consume carbon monoxide generated by CBDB1, thus relieving carbon monoxide autotoxicity. Accumulation of lesser chlorinated chlorobenzene congeners (1,3- and 1,4-dichlorobenzene and 1,3,5-trichlorobenzene) also inhibited dechlorination activity and their removal from the headspace through adsorption to granular activated carbon was shown to restore activity. Proteomic analysis revealed co-culturing strain CBDB1 with Geobacter lovleyi upregulated CBDB1 genes associated with reductive dehalogenases, hydrogenases, formate dehydrogenase, and ribosomal proteins. These data provide insight into CBDB1 ecology and inform strategies for application of CBDB1 in ex situ Hexachlorobenzene destruction technologies.

  • Syntrophic Partners Enhance Growth and Respiratory Dehalogenation of Hexachlorobenzene by Dehalococcoides mccartyi Strain CBDB1
    Frontiers Media S.A., 2018
    Co-Authors: Lorenz Adrian, Anh T. T. Chau, Matthew Lee, Michael J. Manefield
    Abstract:

    This study investigated syntrophic interactions between chlorinated benzene respiring Dehalococcoides mccartyi strain CBDB1 and fermenting partners (Desulfovibrio vulgaris, Syntrophobacter fumaroxidans, and Geobacter lovleyi) during Hexachlorobenzene respiration. Dechlorination rates in syntrophic co-cultures were enhanced 2-3 fold compared to H2 fed CBDB1 pure cultures (0.23 ± 0.04 μmol Cl− day−1). Syntrophic partners were also able to supply cobalamins to CBDB1, albeit with 3–10 fold lower resultant dechlorination activity compared to cultures receiving exogenous cyanocobalamin. Strain CBDB1 pure cultures accumulated ~1 μmol of carbon monoxide per 87.5 μmol Cl− released during Hexachlorobenzene respiration resulting in decreases in dechlorination activity. The syntrophic partners investigated were shown to consume carbon monoxide generated by CBDB1, thus relieving carbon monoxide autotoxicity. Accumulation of lesser chlorinated chlorobenzene congeners (1,3- and 1,4-dichlorobenzene and 1,3,5-trichlorobenzene) also inhibited dechlorination activity and their removal from the headspace through adsorption to granular activated carbon was shown to restore activity. Proteomic analysis revealed co-culturing strain CBDB1 with Geobacter lovleyi upregulated CBDB1 genes associated with reductive dehalogenases, hydrogenases, formate dehydrogenase, and ribosomal proteins. These data provide insight into CBDB1 ecology and inform strategies for application of CBDB1 in ex situ Hexachlorobenzene destruction technologies

  • Table_2_Syntrophic Partners Enhance Growth and Respiratory Dehalogenation of Hexachlorobenzene by Dehalococcoides mccartyi Strain CBDB1.DOCX
    2018
    Co-Authors: Anh T. T. Chau, Lorenz Adrian, Matthew Lee, Michael J. Manefield
    Abstract:

    This study investigated syntrophic interactions between chlorinated benzene respiring Dehalococcoides mccartyi strain CBDB1 and fermenting partners (Desulfovibrio vulgaris, Syntrophobacter fumaroxidans, and Geobacter lovleyi) during Hexachlorobenzene respiration. Dechlorination rates in syntrophic co-cultures were enhanced 2-3 fold compared to H2 fed CBDB1 pure cultures (0.23 ± 0.04 μmol Cl− day−1). Syntrophic partners were also able to supply cobalamins to CBDB1, albeit with 3–10 fold lower resultant dechlorination activity compared to cultures receiving exogenous cyanocobalamin. Strain CBDB1 pure cultures accumulated ~1 μmol of carbon monoxide per 87.5 μmol Cl− released during Hexachlorobenzene respiration resulting in decreases in dechlorination activity. The syntrophic partners investigated were shown to consume carbon monoxide generated by CBDB1, thus relieving carbon monoxide autotoxicity. Accumulation of lesser chlorinated chlorobenzene congeners (1,3- and 1,4-dichlorobenzene and 1,3,5-trichlorobenzene) also inhibited dechlorination activity and their removal from the headspace through adsorption to granular activated carbon was shown to restore activity. Proteomic analysis revealed co-culturing strain CBDB1 with Geobacter lovleyi upregulated CBDB1 genes associated with reductive dehalogenases, hydrogenases, formate dehydrogenase, and ribosomal proteins. These data provide insight into CBDB1 ecology and inform strategies for application of CBDB1 in ex situ Hexachlorobenzene destruction technologies.

  • Image_1_Syntrophic Partners Enhance Growth and Respiratory Dehalogenation of Hexachlorobenzene by Dehalococcoides mccartyi Strain CBDB1.TIFF
    2018
    Co-Authors: Anh T. T. Chau, Lorenz Adrian, Matthew Lee, Michael J. Manefield
    Abstract:

    This study investigated syntrophic interactions between chlorinated benzene respiring Dehalococcoides mccartyi strain CBDB1 and fermenting partners (Desulfovibrio vulgaris, Syntrophobacter fumaroxidans, and Geobacter lovleyi) during Hexachlorobenzene respiration. Dechlorination rates in syntrophic co-cultures were enhanced 2-3 fold compared to H2 fed CBDB1 pure cultures (0.23 ± 0.04 μmol Cl− day−1). Syntrophic partners were also able to supply cobalamins to CBDB1, albeit with 3–10 fold lower resultant dechlorination activity compared to cultures receiving exogenous cyanocobalamin. Strain CBDB1 pure cultures accumulated ~1 μmol of carbon monoxide per 87.5 μmol Cl− released during Hexachlorobenzene respiration resulting in decreases in dechlorination activity. The syntrophic partners investigated were shown to consume carbon monoxide generated by CBDB1, thus relieving carbon monoxide autotoxicity. Accumulation of lesser chlorinated chlorobenzene congeners (1,3- and 1,4-dichlorobenzene and 1,3,5-trichlorobenzene) also inhibited dechlorination activity and their removal from the headspace through adsorption to granular activated carbon was shown to restore activity. Proteomic analysis revealed co-culturing strain CBDB1 with Geobacter lovleyi upregulated CBDB1 genes associated with reductive dehalogenases, hydrogenases, formate dehydrogenase, and ribosomal proteins. These data provide insight into CBDB1 ecology and inform strategies for application of CBDB1 in ex situ Hexachlorobenzene destruction technologies.

  • Enrichment of Hexachlorobenzene and 1,3,5-trichlorobenzene transforming bacteria from sediments in Germany and Vietnam
    Biodegradation, 2013
    Co-Authors: Tran Hoa Duan, Lorenz Adrian
    Abstract:

    Bacterial cultures were enriched from sediments in Germany and Vietnam reductively dechlorinating Hexachlorobenzene and the highly persistent 1,3,5-trichlorobenzene to monochlorobenzene. The main products of the reductive dechlorination of Hexachlorobenzene were monochlorobenzene and dichlorobenzenes (1,2-; 1,3- and 1,4-dichlorobenzene) while no trichlorobenzenes accumulated. For the reductive dechlorination of 1,3,5-trichlorobenzene with the mixed culture from Vietnam sediment, 1,3- dichlorobenzene and monochlorobenzene were produced as intermediate and final end-product, respectively. The pattern of dechlorination did not change when the cultures were repeatedly exposed to oxygen over seven transfers demonstrating oxygen tolerance of the dechlorinating bacteria. However, reductive dechlorination of 1,3,5-trichlorobenzene was inhibited by vancomycin at a concentration of 5 mg L^−1. Vancomycin delayed reductive dechlorination of Hexachlorobenzene in mixed cultures by about 6 months. When repeatedly applied, vancomycin completely abolished the ability of the mixed culture to transform Hexachlorobenzene. Sensitivity to vancomycin and insensitivity to brief exposure of oxygen indicates that the dechlorinating bacteria in the mixed cultures did not belong to the genus Dehalococcoides .

C. G. C. Dekker - One of the best experts on this subject based on the ideXlab platform.

  • Microbial dechlorination of Hexachlorobenzene in a sedimentation area of the Rhine River
    Biogeochemistry, 1993
    Co-Authors: J. E. M. Beurskens, C. G. C. Dekker, J. Jonkhoff, L. Pompstra
    Abstract:

    In sedimentation areas of polluted rivers, microbial dechlorination of chlorinated aromatics may be of great environmental significance. This reaction may take place in the deeper, anaerobic sediment layers and involves replacement of a chlorine in the pollutant molecule by hydrogen. In this study, the microbial dechlorination of Hexachlorobenzene in a sedimentation area of the Rhine River is evaluated by using Rhine water pollution data, concentrations in historical sediment samples and in recent sediment cores, and the results of anaerobic laboratory incubations with Lake Ketelmeer sediment. The various data support the conclusion that microbial dechlorination of Hexachlorobenzene has occurred in the anaerobic sediment. Up to 80% of the Hexachlorobenzene deposited in the early 1970s has been dechlorinated. The maximum half-life of Hexachlorobenzene in the sediment is found to be 7 years.

  • Microbial dechlorination of Hexachlorobenzene in a sedimentation area of the Rhine River
    Biogeochemistry, 1992
    Co-Authors: J. E. M. Beurskens, C. G. C. Dekker, J. Jonkhoff, L. Pompstra
    Abstract:

    In sedimentation areas of polluted rivers, microbial dechlorination of chlorinated aromatics may be of great environmental significance. This reaction may take place in the deeper, anaerobic sediment layers and involves replacement of a chlorine in the pollutant molecule by hydrogen. In this study, the microbial dechlorination of Hexachlorobenzene in a sedimentation area of the Rhine River is evaluated by using Rhine water pollution data, concentrations in historical sediment samples and in recent sediment cores, and the results of anaerobic laboratory incubations with Lake Ketelmeer sediment. The various data support the conclusion that microbial dechlorination of Hexachlorobenzene has occurred in the anaerobic sediment. Up to 80% of the Hexachlorobenzene deposited in the early 1970s has been dechlorinated. The maximum half-life of Hexachlorobenzene in the sediment is found to be 7 years. Two limitations of microbially mediated dechlorination in the natural environment have become clear. In the first place, a residual concentration of about 40 μg/kg remains unaltered in the sediment or transformation rates of this fraction are at least extremely low. Secondly, the lower chlorinated benzenes that are produced from Hexachlorobenzene appear to accumulate in the anaerobic sediment.