Up to 200 million people in 70 countries are at risk from drinking water contaminated with arsenic, which is a major cause of chronic debilitating illnesses and fatal cancers. Until recently little was known about the mobility of arsenic, and how redox transformations determined its movement into or out of water supplies. Although human activities contribute to the release of arsenic from minerals, it is now clear that bacteria are responsible for most of the redox transformation of arsenic in the environment. Bacterial oxidation of arsenite (to the less mobile arsenate) has been known since 1918, but it was not until 2000 that a bacterium was shown to gain energy from this process.
Since then a wide range of arsenite-oxidizing bacteria have been isolated, including aerobes and anaerobes; heterotrophs and autotrophs; thermophiles, mesophiles and psychrophiles. The Metabolism of Arsenite reviews recent advances in the study of such bacteria. After a section on background-geology and health issues the main body of the The Metabolism of Arsenite concerns the cellular machinery of arsenite oxidation. It concludes by examining possible applications. Topics treated are: The geology and cycling of arsenic Arsenic and disease Arsenite oxidation: physiology, enzymes, genes, and gene regulation. Community genomics and functioning, and the evolution of arsenite oxidation Microbial arsenite oxidation in bioremediation Biosensors for arsenic in drinking water and industrial effluents
Arsenic in the environment
D. Kossoff & K.A. Hudson-Edward
Introduction
Chemistry and mineralogy of arsenic
Distribution of arsenic in the environment
Processes of arsenic cycling in the environment
Giant Mine,Yellowknife, Canada: Arsenite waste as the legacy of gold mining and processing
M. Bromstad & H.E. Jamieson
Introduction
Background
Arsenic and arsenite in mine wastes and surrounding area
Transformation and remobilization of arsenic species
Site remediation
Summary
Genotoxic and carcinogenic risk of arsenic exposure. Influence of interindividual genetic variability
R. Marcos & A. Hernández
Introduction
Carcinogenic risk
Genotoxic risk
Genetic polymorphisms affecting carcinogenic risk
Genetic polymorphisms affecting genotoxic risk
Conclusions
Overview of microbial arsenic metabolism and resistance
J.F. Stolz
Introduction
Arsenic resistance
Arsenic in energy generation
Prokaryotic aerobic oxidation of arsenite
T.H. Osborne & J.M. Santini
Introduction
Aerobic arsenite-oxidizing bacteria
Arsenite metabolism
Aerobic arsenite-oxidizing communities
Summary and future directions
Anaerobic oxidation of arsenite by autotrophic bacteria: The view from Mono Lake, California
R.S. Oremland, J.F. Stolz & C.W. Saltikov
Introduction
Nitrate-respiring arsenite-oxidizers
An annotated arsenate reductase that runs in reverse
Anoxygenic photosynthesis fueled by arsenite
Arsenite oxidase
M.D. Heath, B. Schoepp-Cothenet, T.H. Osborne & J.M. Santini
Introduction
Characteristics of the arsenite oxidase
Microbial arsenic response and metabolism in the genomics era
P.N. Bertin, L. Geist, D. Halter, S. Koechler, M. Marchal & F. Arsène-Ploetze
Introduction
Descriptive and comparative genomics
High-throughput genomics reveal the functioning of microorganisms
Conclusions
Arsenite oxidation – regulation of gene expression
M.Wojnowska & S. Djordjevic
Introduction
Multiple modes of arsenite oxidase regulation
AioSR and their involvement in Aio regulation
Quorum sensing
Heat-shock protein DNAJ
Conclusions
Evolution of arsenite oxidation
R. van Lis,W. Nitschke, S. Duval & B. Schoepp-Cothenet
Introduction
Molecular description of arsenic bioenergetic enzymes
Function of the enzymes
Phylogenetic analysis of Aio and Arr
Taking bioenergetics into account
Evolutionary scenario of arsenite oxidation
Remediation using arsenite-oxidizing bacteria
F. Delavat, M.-C. Lett & D. Lièvremont
Introduction
Arsenite oxidation-based remediation bioprocesses
Conclusion
Development of biosensors for the detection of arsenic in drinking water
C. French, K. de Mora, N. Joshi, J. Haseloff & J. Ajioka
Introduction
Biosensors for detection of environmental toxins
Biosensors for arsenic
Conclusions
Subject index