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Arsenate uptake, sequestration and reduction by a freshwater cyanobacterium: a potenial biologic control of arsenic in South TexasMarkley, Christopher Thomas 29 August 2005 (has links)
The toxicity and adverse health effects of arsenic are widely known. It is generally accepted that sorption/desorption reactions with oxy-hydroxide minerals (iron, manganese) control the fate and transport of inorganic arsenic in surface waters through adsorption and precipitation-dissolution processes. In terrestrial environments with limited reactive iron, recent data suggest organoarsenicals are potentially important components of the biogeochemical cycling of arsenic in near-surface environments. Elevated arsenic levels are common in South Texas from geogenic processes (weathering of As-containing rock units) and anthropogenic sources (a byproduct from decades of uranium mining). Sediments collected from South Texas show low reactive iron concentrations, undetectable in many areas, making oxy-hydroxide controls on arsenic unlikely. Studies have shown that eukaryotic algae isolated from arsenic-contaminated waters have increased tolerance to arsenate toxicity and the ability to uptake and biotransform arsenate. In this experiment, net uptake of arsenic over time by a freshwater cyanobacterium never previously exposed to arsenate was quantified as a function of increasing As concentrations and increasing N:P ratios. Toxic effects were not evident when comparing cyanobacterial growth, though extractions indicate accumulation of intracellular arsenic by the cyanobacterium. Increasing N:P ratios has minimal effect on net arsenate uptake over an 18 day period. However, cyanobacteria were shown to reduce arsenate at rates faster than the system can re-oxidize the arsenic suggesting gross arsenate uptake may be much higher. Widespread arsenate reduction by cyanobacterial blooms would increase arsenic mobility and potential toxicity and may be useful as a biomarker of arsenic exposure in oxic surface water environments.
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Arsenate uptake, sequestration and reduction by a freshwater cyanobacterium: a potenial biologic control of arsenic in South TexasMarkley, Christopher Thomas 29 August 2005 (has links)
The toxicity and adverse health effects of arsenic are widely known. It is generally accepted that sorption/desorption reactions with oxy-hydroxide minerals (iron, manganese) control the fate and transport of inorganic arsenic in surface waters through adsorption and precipitation-dissolution processes. In terrestrial environments with limited reactive iron, recent data suggest organoarsenicals are potentially important components of the biogeochemical cycling of arsenic in near-surface environments. Elevated arsenic levels are common in South Texas from geogenic processes (weathering of As-containing rock units) and anthropogenic sources (a byproduct from decades of uranium mining). Sediments collected from South Texas show low reactive iron concentrations, undetectable in many areas, making oxy-hydroxide controls on arsenic unlikely. Studies have shown that eukaryotic algae isolated from arsenic-contaminated waters have increased tolerance to arsenate toxicity and the ability to uptake and biotransform arsenate. In this experiment, net uptake of arsenic over time by a freshwater cyanobacterium never previously exposed to arsenate was quantified as a function of increasing As concentrations and increasing N:P ratios. Toxic effects were not evident when comparing cyanobacterial growth, though extractions indicate accumulation of intracellular arsenic by the cyanobacterium. Increasing N:P ratios has minimal effect on net arsenate uptake over an 18 day period. However, cyanobacteria were shown to reduce arsenate at rates faster than the system can re-oxidize the arsenic suggesting gross arsenate uptake may be much higher. Widespread arsenate reduction by cyanobacterial blooms would increase arsenic mobility and potential toxicity and may be useful as a biomarker of arsenic exposure in oxic surface water environments.
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Studien zur Biotransformation von Guanidinen und Amidinen mit Hepatozyten und Mikrosomen /Wohlers, Hanke. January 1994 (has links)
Thesis (doctoral)--Christian-Albrechts-Universität zu Kiel, 1994.
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Studien zur Charakterisierung der enzymatischen Grundlagen der Biotransformation von Aziden /Brass, Kirsten. January 2002 (has links)
Thesis (doctoral)--Christian-Albrechts-Universität zu Kiel, 2002.
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KINETICS AND REGULATION OF PHASE II XENOBIOTIC METABOLISM IN ISOLATED RAT HEPATOCYTES AND PERFUSED LIVERSundheimer, David William January 1979 (has links)
No description available.
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Biotransformation of monoterpenes and their chlorination productsMisra, Girish 05 1900 (has links)
No description available.
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Regio- and stereospecific biohydroxylation of small-ring moleculesBroad, Susan Ann January 1997 (has links)
No description available.
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The chemistry of reactive nitrosamines and related DNA adducts /Gu, Feng, January 1997 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 225-231). Also available on the Internet.
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Untersuchungen zur Biotransformation der Arzneistoffe Ifosfamid und Trofosfamid /Küpker, Frank. January 1993 (has links) (PDF)
Universiẗat, Diss.--Münster, 1993.
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Untersuchungen zur Wirkung akuter und subakuter Alkoholbelastungen auf Pharmakokinetik und Biotransformation des Nicotins bei einmaliger Nicotin-Gabe und unter steady-state-Bedingungen /Wichmann, Rüdiger. January 1994 (has links) (PDF)
Techn. Univ., Diss.--Braunschweig, 1994.
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