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A tale of two oxidation states: bacterial colonization of arsenic-rich environments.

Muller D, Médigue C, Koechler S, Barbe V, Barakat M, Talla E, Bonnefoy V, Krin E, Arsène-Ploetze F, Carapito C, Chandler M, Cournoyer B, Cruveiller S, Dossat C, Duval S, Heymann M, Leize E, Lieutaud A, Lièvremont D, Makita Y, Mangenot S, Nitschke W, Ortet P, Perdrial N, Schoepp B, Siguier P, Simeonova DD, Rouy Z, Segurens B, Turlin E, Vallenet D, Van Dorsselaer A, Weiss S, Weissenbach J, Lett MC, Danchin A, Bertin PN - PLoS Genet. (2007)

Bottom Line: Although this metalloid is ubiquitous on Earth, thus far no bacterium thriving in arsenic-contaminated environments has been fully characterized.These observations demonstrate the existence of a novel strategy to efficiently colonize arsenic-rich environments, which extends beyond oxidoreduction reactions.Such a microbial mechanism of detoxification, which is possibly exploitable for bioremediation applications of contaminated sites, may have played a crucial role in the occupation of ancient ecological niches on earth.

View Article: PubMed Central - PubMed

Affiliation: Génétique Moléculaire, Génomique et Microbiologie, UMR7156 CNRS and Université Louis Pasteur, Strasbourg, France.

ABSTRACT
Microbial biotransformations have a major impact on contamination by toxic elements, which threatens public health in developing and industrial countries. Finding a means of preserving natural environments-including ground and surface waters-from arsenic constitutes a major challenge facing modern society. Although this metalloid is ubiquitous on Earth, thus far no bacterium thriving in arsenic-contaminated environments has been fully characterized. In-depth exploration of the genome of the beta-proteobacterium Herminiimonas arsenicoxydans with regard to physiology, genetics, and proteomics, revealed that it possesses heretofore unsuspected mechanisms for coping with arsenic. Aside from multiple biochemical processes such as arsenic oxidation, reduction, and efflux, H. arsenicoxydans also exhibits positive chemotaxis and motility towards arsenic and metalloid scavenging by exopolysaccharides. These observations demonstrate the existence of a novel strategy to efficiently colonize arsenic-rich environments, which extends beyond oxidoreduction reactions. Such a microbial mechanism of detoxification, which is possibly exploitable for bioremediation applications of contaminated sites, may have played a crucial role in the occupation of ancient ecological niches on earth.

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Organization of Arsenate-Resistance Operons (ars) in H. arsenicoxydansThe three operons identified by complementation of an E. coli ars-deficient strain code for an ArsR regulator, one or two ArsC arsenate reductases, an As[III] extrusion pump, and an ArsH putative flavoprotein. The fourth operon present in the genome lacks the As[III] pump-encoding gene.
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pgen-0030053-g004: Organization of Arsenate-Resistance Operons (ars) in H. arsenicoxydansThe three operons identified by complementation of an E. coli ars-deficient strain code for an ArsR regulator, one or two ArsC arsenate reductases, an As[III] extrusion pump, and an ArsH putative flavoprotein. The fourth operon present in the genome lacks the As[III] pump-encoding gene.

Mentions: Circles display (from the outside inward): (rings 1 and 2) predicted CDSs transcribed in a clockwise/counterclockwise direction, (ring 3) tRNA (green) and rRNA (violetblue), (ring 4) ISs (yellow) and prophagic regions (violetbrown), (ring 5) clusters of genes involved in arsenic (red; numbered as shown in Figure 4)/metal resistance (dark blue), (ring 6) GC deviation (GCwindow − average GC of genome, using a 1kb window); (7) GC skew (using a 1kb window). The high GC-rich island described in Figure 2 is shown in red.


A tale of two oxidation states: bacterial colonization of arsenic-rich environments.

Muller D, Médigue C, Koechler S, Barbe V, Barakat M, Talla E, Bonnefoy V, Krin E, Arsène-Ploetze F, Carapito C, Chandler M, Cournoyer B, Cruveiller S, Dossat C, Duval S, Heymann M, Leize E, Lieutaud A, Lièvremont D, Makita Y, Mangenot S, Nitschke W, Ortet P, Perdrial N, Schoepp B, Siguier P, Simeonova DD, Rouy Z, Segurens B, Turlin E, Vallenet D, Van Dorsselaer A, Weiss S, Weissenbach J, Lett MC, Danchin A, Bertin PN - PLoS Genet. (2007)

Organization of Arsenate-Resistance Operons (ars) in H. arsenicoxydansThe three operons identified by complementation of an E. coli ars-deficient strain code for an ArsR regulator, one or two ArsC arsenate reductases, an As[III] extrusion pump, and an ArsH putative flavoprotein. The fourth operon present in the genome lacks the As[III] pump-encoding gene.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC1851979&req=5

pgen-0030053-g004: Organization of Arsenate-Resistance Operons (ars) in H. arsenicoxydansThe three operons identified by complementation of an E. coli ars-deficient strain code for an ArsR regulator, one or two ArsC arsenate reductases, an As[III] extrusion pump, and an ArsH putative flavoprotein. The fourth operon present in the genome lacks the As[III] pump-encoding gene.
Mentions: Circles display (from the outside inward): (rings 1 and 2) predicted CDSs transcribed in a clockwise/counterclockwise direction, (ring 3) tRNA (green) and rRNA (violetblue), (ring 4) ISs (yellow) and prophagic regions (violetbrown), (ring 5) clusters of genes involved in arsenic (red; numbered as shown in Figure 4)/metal resistance (dark blue), (ring 6) GC deviation (GCwindow − average GC of genome, using a 1kb window); (7) GC skew (using a 1kb window). The high GC-rich island described in Figure 2 is shown in red.

Bottom Line: Although this metalloid is ubiquitous on Earth, thus far no bacterium thriving in arsenic-contaminated environments has been fully characterized.These observations demonstrate the existence of a novel strategy to efficiently colonize arsenic-rich environments, which extends beyond oxidoreduction reactions.Such a microbial mechanism of detoxification, which is possibly exploitable for bioremediation applications of contaminated sites, may have played a crucial role in the occupation of ancient ecological niches on earth.

View Article: PubMed Central - PubMed

Affiliation: Génétique Moléculaire, Génomique et Microbiologie, UMR7156 CNRS and Université Louis Pasteur, Strasbourg, France.

ABSTRACT
Microbial biotransformations have a major impact on contamination by toxic elements, which threatens public health in developing and industrial countries. Finding a means of preserving natural environments-including ground and surface waters-from arsenic constitutes a major challenge facing modern society. Although this metalloid is ubiquitous on Earth, thus far no bacterium thriving in arsenic-contaminated environments has been fully characterized. In-depth exploration of the genome of the beta-proteobacterium Herminiimonas arsenicoxydans with regard to physiology, genetics, and proteomics, revealed that it possesses heretofore unsuspected mechanisms for coping with arsenic. Aside from multiple biochemical processes such as arsenic oxidation, reduction, and efflux, H. arsenicoxydans also exhibits positive chemotaxis and motility towards arsenic and metalloid scavenging by exopolysaccharides. These observations demonstrate the existence of a novel strategy to efficiently colonize arsenic-rich environments, which extends beyond oxidoreduction reactions. Such a microbial mechanism of detoxification, which is possibly exploitable for bioremediation applications of contaminated sites, may have played a crucial role in the occupation of ancient ecological niches on earth.

Show MeSH
Related in: MedlinePlus