Demethylation of methylarsenic species by <i>Mycobacterium neoaurum</i>

Lehr, Corinne R.; Polishchuk, Elena; Radoja, Una; Cullen, William R.

doi:10.1002/aoc.544

Cited by 46 publications

(30 citation statements)

References 24 publications

(22 reference statements)

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“…An isolate obtained from sludge water, strain ASV2, decomposes arsenobetaine, metabolizing it as carbonic source, 12 and Mycobacterium neoaurum demethylates MMAA(V) to mixtures of arsenate and arsenite. 13 The ecophysiological characteristics of organoarsenic-decomposing bacteria have not been investigated in detail and the decomposition processes in aquatic environments are obscure.…”

Section: Introductionmentioning

confidence: 99%

Seasonal dynamics of dimethylarsinic-acid-decomposing bacteria dominating in Lake Kahokugata

Maki

Hasegawa

Ueda

2005

Appl. Organometal. Chem.

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. Monitoring of bacterial biomass involving DMAA decomposition using the most probable number procedure showed that the bacterial cell densities ranged from 36 to 3600 ml −1 . On the other hand, methylated arsenic was not detected during the experimental period, although the inorganic arsenic concentration was over 4 nM. This suggests that bacteria remineralized methylated arsenic species to inorganic arsenic. Furthermore, the composition of bacterial communities involving DMAA decomposition was examined by restriction-fragment-length polymorphism analysis of the 16S rDNA nucleotide. As a result, a total of 49 isolates were classified into 10 type groups, and 32 of these isolates belonged to three dominant type groups. Phylogenetic analysis using 16S rDNA partial sequences (ca 320 bp) suggests that the representative isolates of the dominant type groups are specific to the summer or winter season. Moreover, as a result of the culture experiments to examine DMAA decomposition activity, the representative isolates decomposed 1 µM DMAA at a decomposition percentage of below 80%. In conclusion, some bacterial communities in a specific season can decompose DMAA to varying degrees, contributing to the annual cycle of arsenic species.

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Section: Introductionmentioning

confidence: 99%

Seasonal dynamics of dimethylarsinic-acid-decomposing bacteria dominating in Lake Kahokugata

Maki

Hasegawa

Ueda

2005

Appl. Organometal. Chem.

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“…Pentavalent organoarsenicals are relatively benign and less toxic than inorganic arsenicals; however, aromatic (8-10) and methyl (11,12) arsenicals are degraded into more toxic inorganic forms in the environment, which may contaminate the foods and water supplies. Although microbial degradation of environmental organoarsenicals has been documented (8,9,11,13), no molecular details of the reaction have been reported. We recently demonstrated that a microbial community in Florida golf course soil carries out a two-step pathway of MSMA reduction and demethylation (14).…”

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confidence: 99%

A C⋅As lyase for degradation of environmental organoarsenical herbicides and animal husbandry growth promoters

Yoshinaga

Rosen

2014

Proc. Natl. Acad. Sci. U.S.A.

127

170

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Arsenic is the most widespread environmental toxin. Substantial amounts of pentavalent organoarsenicals have been used as herbicides, such as monosodium methylarsonic acid (MSMA), and as growth enhancers for animal husbandry, such as roxarsone (4-hydroxy-3-nitrophenylarsonic acid) [Rox(V)]. These undergo environmental degradation to more toxic inorganic arsenite [As(III)]. We previously demonstrated a two-step pathway of degradation of MSMA to As(III) by microbial communities involving sequential reduction to methylarsonous acid [MAs(III)] by one bacterial species and demethylation from MAs(III) to As(III) by another. In this study, the gene responsible for MAs(III) demethylation was identified from an environmental MAs(III)-demethylating isolate, Bacillus sp. MD1. This gene, termed arsenic inducible gene (arsI), is in an arsenic resistance (ars) operon and encodes a nonheme iron-dependent dioxygenase with C·As lyase activity. Heterologous expression of ArsI conferred MAs(III)-demethylating activity and MAs(III) resistance to an arsenic-hypersensitive strain of Escherichia coli, demonstrating that MAs(III) demethylation is a detoxification process. Purified ArsI catalyzes Fe 2+ -dependent MAs(III) demethylation. In addition, ArsI cleaves the C·As bond in trivalent roxarsone and other aromatic arsenicals. ArsI homologs are widely distributed in prokaryotes, and we propose that ArsI-catalyzed organoarsenical degradation has a significant impact on the arsenic biogeocycle. To our knowledge, this is the first report of a molecular mechanism for organoarsenic degradation by a C·As lyase.herbicide resistance | growth promoter degradation

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“…Lehr et al reported that Mycobacterium meoaurum converted about 500 µg/l MMAA to inorganic arsenic at a conversion percentage of 50% within 14 days. 11 The two isolates, C-1 and D-7, would have similar levels of MMAA-mineralization activities as Mycobacterium meoaurum. During the stationary phase in the cultures of two isolates, the MMAA level immediately decreased, while inorganic arsenic gradually increased.…”

Section: Isolatesmentioning

confidence: 98%

“…Previously, Mycobacterium meoaurum was also reported to be MMAA-mineralizing bacteria. 11 In aquatic environments, various species of bacteria are thought to contribute to the mineralization for DMAA. 12,13 Accordingly, the several bacterial species in arsenic-contaminated environments can mineralize harmful organoarsenic compounds.…”

Section: Bacillus Subtilis (Z99104)mentioning

confidence: 99%

“…10 Lehr et al reported that Mycobacterium neoaurum demethylates 0.5 mg/l of monomethylarsonic acid [CH 3 AsO(OH) 2 ; MMAA(V)] to inorganic arsenic, also using MMAA(V) as a carbon source, and the yields of inorganic arsenic were 27% from arsenate and 43% from arsenite. 11 However there are few reports on the biomass and distribution of organoarsenic-mineralizing bacteria. In a previous study, the biomass and composition of bacteria mineralizing dimethylarsinic acid [(CH 3 ) 2 AsO(OH); DMAA(V)] were investigated in lakes, and a bacterial population composed of various bacterial species was demonstrated to contribute to the mineralization cycle of organoarsenic in the aquatic environment.…”

Section: Introductionmentioning

confidence: 99%

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Isolation of monomethylarsonic acid‐mineralizing bacteria from arsenic contaminated soils of Ohkunoshima Island

Maki

Takeda

Hasegawa

et al. 2006

Applied Organom Chemis

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Chemical warfare agents, composed of harmful organoarsenic compounds have contaminated the soils of Ohkunoshima Island with high levels of arsenic. As a basic research establishing useful bioremediation techniques, environmental factors such as arsenic concentrations and bacterial biomass in the soils were investigated. Among the five stations of Ohkunoshima Island, the soils of four stations were contaminated by high levels of arsenic compounds at concentrations of 125, 12.7, 3.29 and 0.504 g/kg soil, while the other station with low arsenic concentrations of 0.007 g/kg soil was considered an uncontaminated area. The distribution of arsenic compounds originating from the chemical weapon agent differs among the various areas of Ohkunoshima Island. The cell densities of arsenate-resistant bacteria also varied among the five stations, ranging from 10 6 to 10 8 cells/g soil. In an attempt to isolate bacteria that strongly mineralize the organoarsenic compounds, the mineralization activities for monomethylarsonic acid [MMAA(V)] of 48 isolates of arsenate-resistant bacteria were determined. Only nine isolates reduced 140 µg/l of MMAA(V), giving decreasing percentages ranging from 5 to 100% within 14 days. Among the nine isolates, two remarkably converted 140 µg/l of MMAA to more than 71 µg/l of inorganic arsenic. Presumably only specific members of the environmental bacterial population have strong mineralization activities for MMAA. Phylogenetic analysis using 16S rDNA sequences showed that the two isolates belonged to the Pseudomonas putida strains, which are known to have strong mineralization activity for various organic compounds. In the soil contaminated by arsenic at a high level, few bacteria in the arsenate-resistant bacterial group would significantly mineralize organoarsenic compounds.

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Demethylation of methylarsenic species by Mycobacterium neoaurum

Cited by 46 publications

References 24 publications

Seasonal dynamics of dimethylarsinic-acid-decomposing bacteria dominating in Lake Kahokugata

Seasonal dynamics of dimethylarsinic-acid-decomposing bacteria dominating in Lake Kahokugata

A C⋅As lyase for degradation of environmental organoarsenical herbicides and animal husbandry growth promoters

Isolation of monomethylarsonic acid‐mineralizing bacteria from arsenic contaminated soils of Ohkunoshima Island

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