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Barry P. Rosen - One of the best experts on this subject based on the ideXlab platform.
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efficient arsenic methylation and volatilization mediated by a novel bacterium from an arsenic contaminated paddy soil
Environmental Science & Technology, 2016Co-Authors: Ke Huang, Barry P. Rosen, Zhu Tang, Chuan Chen, Jun Zhang, Qirong Shen, Fangjie ZhaoAbstract:Microbial arsenic (As) methylation and volatilization are important processes controlling the As biogeochemical cycle in paddy soils. To further understand these processes, we isolated a novel bacterial strain, SM-1, from an As-contaminated paddy soil. SM-1 showed strong As methylation and volatilization abilities, converting almost all arsenite (10 μM) to dimethylarsenate and trimethylarsenic oxide in the medium and Trimethylarsine gas into the headspace within 24 h, with Trimethylarsine accounting for nearly half of the total As. On the basis of the 16S rRNA sequence, strain SM-1 represents a new species in a new genus within the family Cytophagaceae. Strain SM-1 is abundant in the paddy soil and inoculation of SM-1 greatly enhanced As methylation and volatilization in the soil. An arsenite methyltransferase gene (ArarsM) was cloned from SM-1. When expressed in Escherichia coli, ArArsM conferred the As methylation and volatilization abilities to E. coli and increased its resistance to arsenite. The high...
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Volatilization of Arsenic from Polluted Soil by Pseudomonas putida Engineered for Expression of the arsM Arsenic(III) S‑Adenosine Methyltransferase Gene
2015Co-Authors: Jian Chen, Barry P. Rosen, Xiaoxue Wang, Guo-xin Sun, Víctor De Lorenzo, Yong-guan ZhuAbstract:Even though arsenic is one of the most widespread environmental carcinogens, methods of remediation are still limited. In this report we demonstrate that a strain of Pseudomonas putida KT2440 endowed with chromosomal expression of the arsM gene encoding the As(III) S-adenosylmethionine (SAM) methyltransfase from Rhodopseudomonas palustris to remove arsenic from contaminated soil. We genetically engineered the P. putida KT2440 with stable expression of an arsM-gfp fusion gene (GE P. putida), which was inserted into the bacterial chromosome. GE P. putida showed high arsenic methylation and volatilization activity. When exposed to 25 μM arsenite or arsenate overnight, most inorganic arsenic was methylated to the less toxic methylated arsenicals methylarsenate (MAs(V)), dimethylarsenate (DMAs(V)) and Trimethylarsine oxide (TMAs(V)O). Of total added arsenic, the species were about 62 ± 2.2% DMAs(V), 25 ± 1.4% MAs(V) and 10 ± 1.2% TMAs(V)O. Volatilized arsenicals were trapped, and the predominant species were dimethylarsine (Me2AsH) (21 ± 1.0%) and Trimethylarsine (TMAs(III)) (10 ± 1.2%). At later times, more DMAs(V) and volatile species were produced. Volatilization of Me2AsH and TMAs(III) from contaminated soil is thus possible with this genetically engineered bacterium and could be instrumental as an agent for reducing the inorganic arsenic content of soil and agricultural products
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volatilization of arsenic from polluted soil by pseudomonas putida engineered for expression of the arsm arsenic iii s adenosine methyltransferase gene
Environmental Science & Technology, 2014Co-Authors: Jian Chen, Xiaoxue Wang, Victor De Lorenzo, Barry P. RosenAbstract:Even though arsenic is one of the most widespread environmental carcinogens, methods of remediation are still limited. In this report we demonstrate that a strain of Pseudomonas putida KT2440 endowed with chromosomal expression of the arsM gene encoding the As(III) S-adenosylmethionine (SAM) methyltransfase from Rhodopseudomonas palustris to remove arsenic from contaminated soil. We genetically engineered the P. putida KT2440 with stable expression of an arsM-gfp fusion gene (GE P. putida), which was inserted into the bacterial chromosome. GE P. putida showed high arsenic methylation and volatilization activity. When exposed to 25 mu M arsenite or arsenate overnight, most inorganic arsenic was methylated to the less toxic methylated arsenicals methylarsenate (MAs(V)), dimethylarsenate (DMAs(V)) and Trimethylarsine oxide (TMAs(V)O). Of total added arsenic, the species were about 62 +/- 2.2% DMAs(V), 25 +/- 1.4% MAs(V) and 10 +/- 1.2% TMAs(V)O. Volatilized arsenicals were trapped, and the predominant species were dimethylarsine (Me2AsH) (21 +/- 1.0%) and Trimethylarsine (TMAs(III)) (10 +/- 1.2%). At later times, more DMAs(V) and volatile species were produced. Volatilization of Me2AsH and TMAs(III) from contaminated soil is thus possible with this genetically engineered bacterium and could be instrumental as an agent for reducing the inorganic arsenic content of soil and agricultural products.
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biotransformation of arsenic by a yellowstone thermoacidophilic eukaryotic alga
Proceedings of the National Academy of Sciences of the United States of America, 2009Co-Authors: Corinne R Lehr, Chungang Yuan, Chris X Le, Timothy R Mcdermott, Barry P. RosenAbstract:Arsenic is the most common toxic substance in the environment, ranking first on the Superfund list of hazardous substances. It is introduced primarily from geochemical sources and is acted on biologically, creating an arsenic biogeocycle. Geothermal environments are known for their elevated arsenic content and thus provide an excellent setting in which to study microbial redox transformations of arsenic. To date, most studies of microbial communities in geothermal environments have focused on Bacteria and Archaea, with little attention to eukaryotic microorganisms. Here, we show the potential of an extremophilic eukaryotic alga of the order Cyanidiales to influence arsenic cycling at elevated temperatures. Cyanidioschyzon sp. isolate 5508 oxidized arsenite [As(III)] to arsenate [As(V)], reduced As(V) to As(III), and methylated As(III) to form Trimethylarsine oxide (TMAO) and dimethylarsenate [DMAs(V)]. Two arsenic methyltransferase genes, CmarsM7 and CmarsM8, were cloned from this organism and demonstrated to confer resistance to As(III) in an arsenite hypersensitive strain of Escherichia coli. The 2 recombinant CmArsMs were purified and shown to transform As(III) into monomethylarsenite, DMAs(V), TMAO, and Trimethylarsine gas, with a Topt of 60–70 °C. These studies illustrate the importance of eukaryotic microorganisms to the biogeochemical cycling of arsenic in geothermal systems, offer a molecular explanation for how these algae tolerate arsenic in their environment, and provide the characterization of algal methyltransferases.
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biotransformation of arsenic by a yellowstone thermoacidophilic eukaryotic alga
Proceedings of the National Academy of Sciences of the United States of America, 2009Co-Authors: Jie Qin, Chungang Yuan, Corinne R Lehr, Timothy R Mcdermott, Barry P. RosenAbstract:Arsenic is the most common toxic substance in the environment, ranking first on the Superfund list of hazardous substances. It is introduced primarily from geochemical sources and is acted on biologically, creating an arsenic biogeocycle. Geothermal environments are known for their elevated arsenic content and thus provide an excellent setting in which to study microbial redox transformations of arsenic. To date, most studies of microbial communities in geothermal environments have focused on Bacteria and Archaea, with little attention to eukaryotic microorganisms. Here, we show the potential of an extremophilic eukaryotic alga of the order Cyanidiales to influence arsenic cycling at elevated temperatures. Cyanidioschyzon sp. isolate 5508 oxidized arsenite [As(III)] to arsenate [As(V)], reduced As(V) to As(III), and methylated As(III) to form Trimethylarsine oxide (TMAO) and dimethylarsenate [DMAs(V)]. Two arsenic methyltransferase genes, CmarsM7 and CmarsM8, were cloned from this organism and demonstrated to confer resistance to As(III) in an arsenite hypersensitive strain of Escherichia coli. The 2 recombinant CmArsMs were purified and shown to transform As(III) into monomethylarsenite, DMAs(V), TMAO, and Trimethylarsine gas, with a Topt of 60–70 °C. These studies illustrate the importance of eukaryotic microorganisms to the biogeochemical cycling of arsenic in geothermal systems, offer a molecular explanation for how these algae tolerate arsenic in their environment, and provide the characterization of algal methyltransferases.
Kurt J. Irgolic - One of the best experts on this subject based on the ideXlab platform.
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Can Humans Metabolize Arsenic Compounds to Arsenobetaine
Applied Organometallic Chemistry, 1997Co-Authors: Walter Goessler, Claudia Schlagenhaufen, Doris Kuehnelt, Herbert Greschonig, Kurt J. IrgolicAbstract:Arsenic compounds were determined in 21 urine samples collected from a male volunteer. The volunteer was exposed to arsenic through either consumption of codfish or inhalation of small amounts of (CH3)3As present in the laboratory air. The arsenic compounds in the urine were separated and quantified with an HPLC–ICP–MS system equipped with a hydraulic high-pressure nebulizer. This method has a determination limit of 0.5 μg As dm−3 urine. To eliminate the influence of the density of the urine, creatinine was determined and all concentrations of arsenic compounds were expressed in μg As g−1 creatinine. The concentrations of arsenite, arsenate and methylarsonic acid in the urine were not influenced by the consumption of seafood. Exposure to Trimethylarsine doubled the concentration of arsenate and increased the concentration of methylarsonic acid drastically (0.5 to 5 μg As g−1 creatinine). The concentration of dimethylarsinic acid was elevated after the first consumption of fish (2.8 to 4.3 μg As g−1 creatinine), after the second consumption of fish (4.9 to 26.5 μg As g−1 creatinine) and after exposure to trimethyl- arsine (2.9 to 9.6 μg As g−1 creatinine). As expected, the concentration of arsenobetaine in the urine increased 30- to 50-fold after the first consumption of codfish. Surprisingly, the concentration of arsenobetaine also increased after exposure to Trimethylarsine, from a background of approximately 1 μg As g−1 creatinine up to 33.1 μg As g−1 creatinine. Arsenobetaine was detected in all the urine samples investigated. The arsenobetaine in the urine not ascribable to consumed seafood could come from food items of terrestrial origin that—unknown to us—contain arsenobetaine. The possibility that the human body is capable of metabolizing trimethyl- arsine to arsenobetaine must be considered. © 1997 by John Wiley & Sons, Ltd.
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Retention behavior of arsenobetaine, arsenocholine, Trimethylarsine oxide and tetramethylarsonium iodide on a styrene-divinylbenzene column with benzenesulfonates as ion-pairing reagents
Journal of Chromatography A, 1996Co-Authors: Jürgen Gailer, Kurt J. IrgolicAbstract:Abstract The pH-dependent retention behavior of arsenobetaine, arsenocholine, Trimethylarsine oxide, tetramethylarsonium iodide (cationic arsenic compounds), arsenite, arsenate, methylarsonic acid, and dimethylarsinic acid (anionic arsenic compounds) was studied on a Hamilton PRP-1 reversed-phase column (250×4.1 mm I.D.) with 10 m M aqueous solutions of benzensulfonic acids (X-C 6 H 4 SO 3 − ; X=H, 4-HO, 3-CO 2 H; 4-HO-3-HO 2 C-C 6 H 3 SO 3 − ) as ion-pairing reagents in the pH range 2–5 using flame atomic absorption spectrometry as the arsenic-specific detector. The dependencies of the k ′-values of the ‘cationic’ arsenic compounds was rationalized on the basis of the protonation/deprotonation behavior of the arsenic compounds and of the four benzenesulfonates. The results provided evidence for the formation of a cationic species from Trimethylarsine oxide below pH 3. Benzenesulfonate is the most hydrophobic ion-pairing reagent causing strong retention of the cationic arsenic compounds and consequently impeding their rapid separation. With the less hydrophobic, substituted benzenesulfonates the cationic arsenic compounds had retention times not exceeding 6 min. At a flow-rate of 1.5 cm 3 min −1 10 m M aqueous 3-carboxy-4-hydroxybenzenesulfonate solution adjusted to pH 3.5 allowed the separation of arsenate, methylarsonic acid, arsenobetaine, Trimethylarsine oxide, the tetramethylarsonium ion, and arsenocholine within 3 min. Dimethylarsinic acid coelutes with arsenobetaine at pH 3.5, but can be separated from arsenobetaine with the same mobile phase at pH 2.5. At pH 2.5 the signals for Trimethylarsine oxide, the tetramethylarsonium ion, and arsenocholine are too broad to be useful for quantification. Arsenite and methylarsonic acid cannot be separated under these conditions.
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In‐vitro prenatal toxicity of Trimethylarsine, Trimethylarsine oxide and Trimethylarsine sulfide
Applied Organometallic Chemistry, 1995Co-Authors: T. Rick Irvin, Kurt J. IrgolicAbstract:The embryolethality and the embryotoxicity of Trimethylarsine, Trimethylarsine oxide and Trimethylarsine sulfide were investigated employing Sprague–Dawley rat embryos with intact yolk sacs. The embryos were removed on day 11 of gestation and grown in a culture medium (Way-mouth's 725/1) spiked with the arsenic compounds to concentrations in the range 4–100 mM in the presence or absence of rat liver (S-9) homogenate. After 24 h the yolk-sac circulation and heart beat were monitored (indicator of embryolethality), the crown-to-rump lengths were measured, the neural structures (somites) counted, and the development of the limb buds evaluated (indicators of embryotoxicity). At a Trimethylarsine concentration of 18.7 mM 78% of the embryos were dead when no S-9 was present. In the presence of S-9 all embryos survived but were necrotic and malformed. Signs of embryotoxicity were observed at concentrations of 18.7 and 9.3 mM. At the 4.7 mM concentration the embryos grew as well as the control embryos. Trimethylarsine oxide v as lethal at 100 mM and severely embryotoxic at 50 and 25 mM. At all but the lowest concentration (4.5 mM) the embryos looked sick, and were frequently necrotic, deformed and underdeveloped. Trimethylarsine sulfide exhibited severe embryotoxicity at 50 mM concentration in the absence and in the presence of S-9. Signs of acute toxicity were observable at 9 mM concentrations of Trimethylarsine and Trimethylarsine oxide. Compared with other environmental toxicants that show effects at concentrations orders of magnitude smaller, these arsenic compounds cannot be classified as very toxic.
Walter Goessler - One of the best experts on this subject based on the ideXlab platform.
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a unique arsenic speciation profile in elaphomyces spp deer truffles Trimethylarsine oxide and methylarsonous acid as significant arsenic compounds
Analytical and Bioanalytical Chemistry, 2018Co-Authors: Simone Braeuer, Jan Borovicka, Walter GoesslerAbstract:Arsenic and its species were investigated for the first time in nine collections of Elaphomyces spp. (“deer truffles”) from the Czech Republic with inductively coupled plasma mass spectrometry (ICPMS) and high-performance liquid chromatography coupled to ICPMS. The total arsenic concentrations ranged from 12 to 42 mg kg−1 dry mass in samples of E. asperulus and from 120 to 660 mg kg−1 dry mass in E. granulatus and E. muricatus. These concentrations are remarkably high for terrestrial organisms and demonstrate the arsenic-accumulating ability of these fungi. The dominating arsenic species in all samples was methylarsonic acid which accounted for more than 30% of the extractable arsenic. Arsenobetaine, dimethylarsinic acid, and inorganic arsenic were present as well, but only at trace concentrations. Surprisingly, we found high amounts of Trimethylarsine oxide in all samples (0.32–28% of the extractable arsenic). Even more remarkable was that all but two samples contained significant amounts of the highly toxic trivalent arsenic compound methylarsonous acid (0.08–0.73% of the extractable arsenic). This is the first report of the occurrence of Trimethylarsine oxide and methylarsonous acid at significant concentrations in a terrestrial organism. Our findings point out that there is still a lot to be understood about the biotransformation pathways of arsenic in the terrestrial environment.
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Bacterial degradation of arsenobetaine via dimethylarsinoylacetate
Archives of Microbiology, 2003Co-Authors: Richard O. Jenkins, Walter Goessler, John S. Edmonds, Doris Kuehnelt, Alisdair W. Ritchie, Nathalie Molenat, Christopher F. Harrington, Peter G. SuttonAbstract:Microorganisms from Mytilus edulis (marine mussel) degraded arsenobetaine, with the formation of Trimethylarsine oxide, dimethylarsinate and methylarsonate. Four bacterial isolates from these mixed-cultures were shown by HPLC/hydride generation-atomic fluorescence spectroscopy (HPLC/HG-AFS) analysis to degrade arsenobetaine to dimethylarsinate in pure culture; there was no evidence of Trimethylarsine oxide formation. Two of the isolates ( Paenibacillus sp. strain 13943 and Pseudomonas sp. strain 13944) were shown by HPLC/inductively coupled plasma-mass spectrometry (HPLC/ICPMS) analysis to degrade arsenobetaine by initial cleavage of a methyl-arsenic bond to form dimethylarsinoylacetate, with subsequent cleavage of the carboxymethyl-arsenic bond to yield dimethylarsinate. Arsenobetaine biodegradation by pure cultures was biphasic, with dimethylarsinoylacetate accumulating in culture supernatants during the culture growth phase and its removal accompanying dimethylarsinate formation during a carbon-limited stationary phase. The Paenibacillus sp. also converted exogenously supplied dimethylarsinoylacetate to dimethylarsinate only under carbon-limited conditions. Lysed-cell extracts of the Paenibacillus sp. showed constitutive expression of enzyme(s) capable of arsenobetaine degradation through methyl-arsenic and carboxymethyl-arsenic bond cleavage. The work establishes the capability of particular bacteria to cleave both types of arsenic-carbon bonds of arsenobetaine and demonstrates that mixed-community functioning is not an obligate requirement for arsenobetaine biodegradation.
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organoarsenic compounds in plants and soil on top of an ore vein
Applied Organometallic Chemistry, 2002Co-Authors: Anita Geiszinger, Walter Goessler, Walter KosmusAbstract:Plants and soil collected above an ore vein in Gasen (Austria) were investigated for total arsenic concentrations by inductively coupled plasma mass spectrometry (ICP-MS). Total arsenic concentrations in all samples were higher than those usually found at non-contaminated sites. The arsenic concentration in the soil ranged from ∼700 to ∼4000 mg kg−1 dry mass. Arsenic concentrations in plant samples ranged from ∼0.5 to 6 mg kg−1 dry mass and varied with plant species and plant part. Examination of plant and soil extracts by high-performance liquid chromatography–ICP-MS revealed that only small amounts of arsenic (<1%) could be extracted from the soil and the main part of the extractable arsenic from soil was inorganic arsenic, dominated by arsenate. Trimethylarsine oxide and arsenobetaine were also detected as minor compounds in soil. The extracts of the plants (Trifolium pratense, Dactylis glomerata, and Plantago lanceolata) contained arsenate, arsenite, methylarsonic acid, dimethylarsinic acid, Trimethylarsine oxide, the tetramethylarsonium ion, arsenobetaine, and arsenocholine (2.5–12% extraction efficiency). The arsenic compounds and their concentrations differed with plant species. The extracts of D. glomerata and P. lanceolata contained mainly inorganic arsenic compounds typical of most other plants. T. pratense, on the other hand, contained mainly organic arsenicals and the major compound was methylarsonic acid. Copyright © 2002 John Wiley & Sons, Ltd.
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Arsenic compounds in terrestrial organisms. IV. Green plants and lichens from an old arsenic smelter site in Austria
Applied Organometallic Chemistry, 2000Co-Authors: Doris Kuehnelt, Josef Lintschinger, Walter GoesslerAbstract:Two lichens and 12 green plants growing at a former arsenic roasting facility in Austria were analyzed for total arsenic by ICP–MS, and for 12 arsenic compounds (arsenous acid, arsenic acid, dimethylarsinic acid, methylarsonic acid, arsenobetaine, arsenocholine, Trimethylarsine oxide, the tetramethylarsonium cation and four arsenoriboses) by HPLC–ICP–MS. Total arsenic concentrations were in the range of 0.27 mg As (kg dry mass)−1 (Vaccinium vitis idaea) to 8.45 mg As (kg dry mass)−1 (Equisetum pratense). Arsenic compounds were extracted with two different extractants [water or methanol/water (9:1)]. Extraction yields achieved with water [7% (Alectoria ochroleuca) to 71% (Equisetum pratense)] were higher than those with methanol/water (9:1) [4% (Alectoria ochroleuca) to 22% (Deschampsia cespitosa)]. The differences were caused mainly by better extraction of inorganic arsenic (green plants) and an arsenoribose (lichens) by water. Inorganic arsenic was detected in all extracts. Dimethylarsinic acid was identified in nine green plants. One of the lichens (Alectoria ochroleuca) contained traces of methylarsonic acid, and this compound was also detected in nine of the green plants. Arsenobetaine was a major arsenic compound in extracts of the lichens, but except for traces in the grass Deschampsia cespitosa, it was not detected in the green plants. In contrast to arsenobetaine, Trimethylarsine oxide was found in all samples. The tetramethylarsonium cation was identified in the lichen Alectoria ochroleuca and in four green plants. With the exception of the needles of the tree Larix decidua the arsenoribose (2′R)-dimethyl[1-O-(2′,3′-dihydroxypropyl)-5-deoxy-β-D-ribofuranos-5-yl]arsine oxide was identified at the low μg kg−1 level or as a trace in all plants investigated. In the lichens an unknown arsenic compound, which did not match any of the standard compounds available, was also detected. Arsenocholine and three of the arsenoriboses were not detected in the samples. Copyright © 2000 John Wiley & Sons, Ltd.
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Uptake of arsenate, Trimethylarsine oxide, and arsenobetaine by the shrimp Crangon crangon
Marine Biology, 1998Co-Authors: Douglas A. Hunter, Walter Goessler, Kevin A. FrancesconiAbstract:Common shrimp, Crangon crangon (L.), were exposed to inorganic arsenic (arsenate), Trimethylarsine oxide, or arsenobetaine in sea water (100 l gA s l )1 ) or in food (1 mg As g )1 wet wt) for up to 24 d, followed by 16 d depuration in clean sea water with undosed food, in order to determine the eAciency of uptake and retention of the compounds. Accumulation of arsenic in the tail muscle, gills, midgut gland, exoskeleton, and remaining tissues was found to depend on the chemical form of the arsenic and the route of exposure. No arsenic was accumulated by C. crangon exposed to arse- nate or Trimethylarsine oxide in sea water. Shrimps ex- posed to waterborne arsenobetaine initially accumulated a small amount of arsenic in their tail muscle and gills. After 16 d, C. crangon fed arsenate, Trimethylarsine ox- ide, or arsenobetaine had accumulated arsenic in their tail muscle to levels 2-, 2-, or 40-times, respectively, that of the control group. A roughly linear rate of ac- cumulation was shown by shrimps fed Trimethylarsine oxide or arsenobetaine, but C. crangon fed arsenate ac- cumulated arsenic for 16 d, then lost arsenic such that their concentration on Day 24 was not significantly diAerent from that of the control group. Patterns of arsenic accumulation in the gills of shrimps fed the compounds were similar to those seen in the tail muscle. On a whole animal basis, C. crangon retained1.2% of the arsenate, 1.6% of the Trimethylarsine oxide, and 42% of the arsenobetaine consumed over the first 16 d of exposure, with roughly half present in the tail muscle in each case. Data obtained support the view that the direct uptake of arsenobetaine from sea water does not make a significant contribution to the relatively high concentrations of this compound in marine crustaceans, and that food is the primary source. Naturally occurring arsenic compounds in C. crangon and possible trans- formations of the administered arsenic compounds were examined by high performance liquid chromatography using an inductively coupled plasma mass spectrometer as the arsenic-specific detector. Control C. crangon contained arsenobetaine as the major arsenic compound (>95% of total arsenic); tetramethylarsonium ion (0.7%) and an unknown arsenic compound (1.7%) were also present as minor constituents. Shrimp ingesting arsenobetaine accumulated it unchanged. Shrimp in- gesting arsenate did not form methylated arsenic com- pounds; they appeared to contain their accumulated arsenic as unchanged arsenate only, although the pos- sibility that some of the arsenic was reduced to arsenite could not be excluded. C. crangon ingesting trimethyl- arsine oxide biotransformed the compound predomi- nantly to dimethylarsinate.
Toshikazu Kaise - One of the best experts on this subject based on the ideXlab platform.
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Biotransformation of arsenobetaine to Trimethylarsine oxide by marine microorganisms in a gill of clam Meretrix lusoria
Chemosphere, 1998Co-Authors: Toshikazu Kaise, Teruaki Sakurai, Tohru Saitoh, Chiyo Matsubara, Naoko Takada-oikawa, Ken'ichi HanaokaAbstract:The tetramethylarsonium ion has been found in the gill of the clam Meretrix lusoria. We attempted to confirm the conversion of arsenobetaine to the tetramethylarsonium ion in a culture with marine microorganisms occurring in the gill of the clam Meretrix lusoria. Arsenobetaine was aerobically incubated with microorganisms. A garlic-like odor was faintly detected after 5 to 8 days incubation. The mass spectrum of the odorous substance was essentially identical with that of synthetic Trimethylarsine. Trimethylarsine oxide (TMAO) was also detected in the culture medium after 3 weeks incubation. Arsenobetaine was biotransformed to TMAO during the incubation in the culture growth by the marine microorganisms. Tetramethylarsonium ion was not detected in the culture medium even after 72 days incubation.
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Degradation of arsenobetaine to inorganic arsenic by bacteria in seawater
Hydrobiologia, 1995Co-Authors: Ken'ichi Hanaoka, Shoji Tagawa, Osamu Nakamura, Hiroshi Ohno, Toshikazu KaiseAbstract:The substances suspended in seawater were fractionated by membrane filtration into three fractions. Fraction 1 was collected on a membrane filter of 0.22 µm pore-size, fraction 2 on a 5 µm pore-size and fraction 3 on 0.22 µm pore-size from the filtrate passed through the 5 µm membrane filter. Arsenobetaine was incubated with each of these fractions in two media (ZoBell 2216E and a solution of inorganic salts) at 25 °C in the dark under aerobic conditions. The mixture added with fraction 3 was considered to contain only bacteria. In every case, in the inorganic salt medium, inorganic arsenic(V) was derived from arsenobetaine via Trimethylarsine oxide. In the ZoBell medium, arsenobetaine was not degraded to inorganic arsenic, although Trimethylarsine oxide was derived in every case. We conclude that the degradation of arsenobetaine to Trimethylarsine oxide or inorganic arsenic can be accomplished in seawater by bacteria alone.
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formation of arsenobetaine from arsenocholine by micro organisms occurring in sediments
Applied Organometallic Chemistry, 1992Co-Authors: Ken'ichi Hanaoka, Shoji Tagawa, Takeharu Satow, Toshikazu KaiseAbstract:As one of the experiments to pursue marine circulation of arsenic, we studied microbiological conversion of arsenocholine to arsenobetaine, because arsenocholine may be a precursor of arsenobetaine in these ecosystems. Two culture media, 1/5 ZoBell 2216E and an aqueous solution of inorganic salts, were used in this in vitro study. To each medium (25 cm3) were added synthetic arsenocholine (0.2%) and about 1 g of the sediment, and they were aerobically incubated at 25°C in the dark. These conversion experiments were performed in May and July 1990. In both seasons, two or three metabolites were derived in each mixture. These metabolites were purified using cation-exchange chromatography. Their structures were confirmed as arsenobetaine, Trimethylarsine oxide and dimethylarsinic acid by high-performance liquid chromatography, thin-layer chromatography, FAB mass spectrometry and a combination of gas-chromatographic separation with hydride generation followed by a cold-trap technique and selected-ion monitoring mass spectrometric analysis. From this and other evidence it is concluded that, in the arsenic cycle in these marine ecosystems, as recently postulated by us, the pathway arsenocholine arsenobetaine Trimethylarsine oxide dimethylarsinic acid methanearsonic acid inorganic arsenic can be carried out by micro-organisms alone.
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The fate of organoarsenic compounds in marine ecosystems
Applied Organometallic Chemistry, 1992Co-Authors: Ken′ichi Hanaoka, Shoji Tagawa, Toshikazu KaiseAbstract:Microbial degradation experiments were performed with each standard arsenical [arsenobetaine, Trimethylarsine oxide, dimethylarsinic acid, methanearsonic acid, inorganic arsenic(V) and inorganic arsenic(III)]. As typical origins for marine micro-organisms, sediments, macro-algae, mollusc intestine and suspended substances were used. The results were from these experiments led us to the following conclusions: (1) there is an arsenic cycle which begins with the methylation of inorganic arsenic on the route to arsenobetaine and terminates with the complete degradation of arsenobetaine to inorganic arsenic; (2) all the organoarsenic compounds which are derived from inorganic arsenic in seawater, through the food chains, have the fate that they, at least in part, finally return to the original inorganic arsenic.
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The degradation of arsenobetaine to inorganic arsenic by sedimentary microorganisms
Sediment Water Interactions, 1992Co-Authors: Ken'ichi Hanaoka, Shoji Tagawa, Toshikazu KaiseAbstract:Two growth media containing arsenobetaine [(CH3)3 As+ CH2COO−] were mixed with coastal marine sediments, the latter providing a source of microorganisms. The mixtures were kept at 25 °C in the dark and shaken for several weeks under an atmosphere of air. The disappearance of arsenobetaine and the appearance of two metabolites were followed by HPLC. The HPLC-retention time of the first metabolite agreed with that of Trimethylarsine oxide [(CH3)3AsO]. The second metabolite was identified as arsenate (As(V)) using hydride generation/cold trap/GC MS analysis and thin layer chromatography. This is the first scientific evidence showing that arsenobetaine is degraded by microorganisms to inorganic arsenic via Trimethylarsine oxide. The degradation of arsenobetaine to inorganic arsenic completes the marine arsenic cycle that begins with the methylation of inorganic arsenic on the way to arsenobetaine.
Andrew A. Meharg - One of the best experts on this subject based on the ideXlab platform.
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Biovolatilization of Arsenic as Arsines from Seawater
2018Co-Authors: Laurie Savage, Manus Carey, Paul N. Williams, Andrew A. MehargAbstract:Marine sources of arsenic to the atmosphere are normally dismissed as minor. Here we show that arsenic can be biovolatilized from seawater, and that biovolatilzation is based on organic arsenic species present in the seawater. Even though inorganic arsenic is in great excess in seawaters, it is Trimethylarsine (TMA) that is the primary biovolatilized product, with dimethylarsine (DMA) also observed if dimethylarsinic acid (DMAA) is spiked into seawaters. With respect to budgets, 0.04% of the total arsenic in the seawater was biovolatilized over a 2-week incubation period. To test the environmental significance of this finding, wet deposition was analyzed for arsenic species at coastal locations, one of which was the origin of the seawater. It was found that the oxidized product of TMA, Trimethylarsine oxide (TMAO), and to a less extent DMAA were widely present. When outputs for arsines (0.9 nmol/m2/d) from seawater and inputs from wet deposition (0.3–0.5 nmol/m2/d) were compared, they were of the same order of magnitude. These findings provide impetus to reexamining the global arsenic cycle, as there is now a need to determine the flux of arsines from the ocean to the atmosphere
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Elevated Trimethylarsine Oxide and Inorganic Arsenic in Northern Hemisphere Summer Monsoonal Wet Deposition
Environmental Science & Technology, 2017Co-Authors: Laurie Savage, Manus Carey, Mahmud Hossain, M. Rafiqul Islam, P. Mangala C.s. De Silva, Paul N. Williams, Andrew A. MehargAbstract:For arsenic speciation, the inputs for wet deposition are not well understood. Here we demonstrate that Trimethylarsine oxide (TMAO) and inorganic arsenic are the dominant species in monsoonal wet deposition in the summer Indian subcontinent, Bangladesh, with inorganic arsenic dominating, accounting for ∼80% of total arsenic in this medium. Lower concentrations of both species were found in monsoonal wet deposition in the winter Indian subcontinent, Sri Lanka. The only other species present was dimethylarsinic acid (DMAA), but this was usually below limits of detection (LoD). We hypothesize that TMAO and inorganic arsenic in monsoonal wet deposition are predominantly of marine origin. For TMAO, the potential source is the atmospheric oxidation of marine derived Trimethylarsine. For inorganic arsenic, our evidence suggests entrainment of water column inorganic arsenic into atmospheric particulates. These conclusions are based on weather trajectory analysis and on the strong correlations with known wet depo...
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Elevated Trimethylarsine Oxide and Inorganic Arsenic in Northern Hemisphere Summer Monsoonal Wet Deposition
2017Co-Authors: Laurie Savage, Manus Carey, Mahmud Hossain, Paul N. Williams, Rafiqul M. Islam, Mangala P. C. S. De Silva, Andrew A. MehargAbstract:For arsenic speciation, the inputs for wet deposition are not well understood. Here we demonstrate that Trimethylarsine oxide (TMAO) and inorganic arsenic are the dominant species in monsoonal wet deposition in the summer Indian subcontinent, Bangladesh, with inorganic arsenic dominating, accounting for ∼80% of total arsenic in this medium. Lower concentrations of both species were found in monsoonal wet deposition in the winter Indian subcontinent, Sri Lanka. The only other species present was dimethylarsinic acid (DMAA), but this was usually below limits of detection (LoD). We hypothesize that TMAO and inorganic arsenic in monsoonal wet deposition are predominantly of marine origin. For TMAO, the potential source is the atmospheric oxidation of marine derived Trimethylarsine. For inorganic arsenic, our evidence suggests entrainment of water column inorganic arsenic into atmospheric particulates. These conclusions are based on weather trajectory analysis and on the strong correlations with known wet deposition marine derived elements: boron, iodine, and selenium. The finding that TMAO and inorganic arsenic are widely present and elevated in monsoonal wet deposition identifies major knowledge gaps that need to be addressed regarding the understanding of arsenic’s global cycle
