RESUMO
In this study, new strains were isolated from an environment with elevated arsenic levels, Sainte-Marie-aux-Mines (France), and the diversity of aoxB genes encoding the arsenite oxidase large subunit was investigated. The distribution of bacterial aoxB genes is wider than what was previously thought. AoxB subfamilies characterized by specific signatures were identified. An exhaustive analysis of AoxB sequences from this study and from public databases shows that horizontal gene transfer has likely played a role in the spreading of aoxB in prokaryotic communities.
Assuntos
Archaea/enzimologia , Archaea/metabolismo , Arsenitos/metabolismo , Bactérias/enzimologia , Bactérias/metabolismo , Microbiologia Ambiental , Oxirredutases/genética , Archaea/genética , Archaea/isolamento & purificação , Bactérias/genética , Bactérias/isolamento & purificação , Análise por Conglomerados , DNA Arqueal/química , DNA Arqueal/genética , DNA Bacteriano/química , DNA Bacteriano/genética , França , Dados de Sequência Molecular , Oxirredução , Filogenia , Análise de Sequência de DNA , Homologia de SequênciaRESUMO
The arsenic resistance gene cluster of Microbacterium sp. A33 contains a novel pair of genes (arsTX) encoding a thioredoxin system that are cotranscribed with an unusual arsRC2 fusion gene, ACR3, and arsC1 in an operon divergent from arsC3. The whole ars gene cluster is required to complement an Escherichia coli ars mutant. ArsRC2 negatively regulates the expression of the pentacistronic operon. ArsC1 and ArsC3 are related to thioredoxin-dependent arsenate reductases; however, ArsC3 lacks the two distal catalytic cysteine residues of this class of enzymes.
Assuntos
Actinomycetales/genética , Arsênio/toxicidade , Óperon , Actinomycetales/efeitos dos fármacos , Actinomycetales/metabolismo , Arseniato Redutases/genética , Arseniato Redutases/metabolismo , Arsênio/metabolismo , ATPases Transportadoras de Arsenito/genética , ATPases Transportadoras de Arsenito/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Clonagem Molecular , Sequência Conservada , Farmacorresistência Bacteriana/genética , Escherichia coli/genética , Escherichia coli/metabolismo , Regulação Bacteriana da Expressão Gênica , Genes Bacterianos , Teste de Complementação Genética , Genoma Bacteriano , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Família Multigênica , Análise de Sequência de DNA , Tiorredoxinas/metabolismoRESUMO
Arsenic-resistant prokaryote diversity is far from being exhaustively explored. In this study, the arsenic-adapted prokaryotic community present in a moderately arsenic-contaminated site near Sainte-Marie-aux-Mines (France) was characterized, using metaproteomic and 16S rRNA-encoding gene amplification. High prokaryotic diversity was observed, with a majority of Proteobacteria, Acidobacteria and Bacteroidetes, and a large archaeal community comprising Euryarchaeaota and Thaumarchaeota. Metaproteomic analysis revealed that Proteobacteria, Planctomycetes and Cyanobacteria are among the active bacteria in this ecosystem. Taken together, these results highlight the unsuspected high diversity of the arsenic-adapted prokaryotic community, with some phyla never having been described in highly arsenic-exposed sites.