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FEMS Microbiology Letters Aug 2017A number of prokaryotes are capable of employing arsenic oxy-anions as either electron acceptors [arsenate; As(V)] or electron donors [arsenite; As(III)] to sustain... (Review)
Review
A number of prokaryotes are capable of employing arsenic oxy-anions as either electron acceptors [arsenate; As(V)] or electron donors [arsenite; As(III)] to sustain arsenic-dependent growth ('arsenotrophy'). A subset of these microorganisms function as either chemoautotrophs or photoautotrophs, whereby they gain sufficient energy from their redox metabolism of arsenic to completely satisfy their carbon needs for growth by autotrophy, that is the fixation of inorganic carbon (e.g. HCO3-) into their biomass. Here we review what has been learned of these processes by investigations we have undertaken in three soda lakes of the western USA and from the physiological characterizations of the relevant bacteria, which include the critical genes involved, such as respiratory arsenate reductase (arrA) and the discovery of its arsenite-oxidizing counterpart (arxA). When possible, we refer to instances of similar process occurring in other, less extreme ecosystems and by microbes other than haloalkaliphiles.
Topics: Arsenates; Arsenic; Bacteria; Bacterial Physiological Phenomena; Carbon Cycle; Chemoautotrophic Growth; Ecosystem; Lakes; Oxidation-Reduction; Phylogeny
PubMed: 28859313
DOI: 10.1093/femsle/fnx146 -
Science (New York, N.Y.) May 2003Arsenic is a metalloid whose name conjures up images of murder. Nonetheless, certain prokaryotes use arsenic oxyanions for energy generation, either by oxidizing... (Review)
Review
Arsenic is a metalloid whose name conjures up images of murder. Nonetheless, certain prokaryotes use arsenic oxyanions for energy generation, either by oxidizing arsenite or by respiring arsenate. These microbes are phylogenetically diverse and occur in a wide range of habitats. Arsenic cycling may take place in the absence of oxygen and can contribute to organic matter oxidation. In aquifers, these microbial reactions may mobilize arsenic from the solid to the aqueous phase, resulting in contaminated drinking water. Here we review what is known about arsenic-metabolizing bacteria and their potential impact on speciation and mobilization of arsenic in nature.
Topics: Archaea; Arsenates; Arsenic; Arsenic Poisoning; Arsenicals; Arsenites; Bacteria; Biomass; Biotransformation; Ecosystem; Environmental Microbiology; Humans; Models, Biological; Oxidation-Reduction; Thermodynamics; Water Pollutants, Chemical; Water Supply
PubMed: 12738852
DOI: 10.1126/science.1081903 -
Environmental Science & Technology Nov 2022The microbial metabolism of arsenic plays a prominent role in governing the biogeochemical cycle of arsenic. Although diverse microbes are known to be involved in the...
The microbial metabolism of arsenic plays a prominent role in governing the biogeochemical cycle of arsenic. Although diverse microbes are known to be involved in the redox transformation of inorganic arsenic, the underlying mechanisms about the arsenic redox cycle mediated by a single microbial strain remain unclear yet. Herein, we discover that CN32, a well-known arsenate-respiring and dissimilatory metal-reducing bacterium, could mediate the reversible arsenic redox transformation under aerobic conditions. Genetic analysis shows that CN32 contains both and operon but lacks an As(III) oxidase encoding gene. Arsenic(V) reduction tests demonstrate that the operon is advantageous but not essential for As(V) respiration in CN32. The Arr complex encoded by the operon not only plays a crucial role in arsenate respiration under anaerobic conditions but also participates in the sequential process of As(V) reduction and As(III) oxidation under aerobic conditions. The Arr enzyme also contributes to the microbial As(III) resistance. The expression and catalysis directionality of Arr in CN32 are regulated by the carbon source types. Our results highlight the complexity of arsenic redox biotransformation in environments and provide new insights into the important contribution of Arr to the As biogeochemical cycle in nature.
Topics: Arsenates; Arsenic; Arsenicals; Shewanella putrefaciens; Oxidation-Reduction
PubMed: 36268776
DOI: 10.1021/acs.est.2c02015 -
Toxicology Letters Mar 2002Symptomatic arsenic poisoning is not often seen in occupational exposure settings. Attempted homicide and deliberate long-term poisoning have resulted in chronic... (Review)
Review
Symptomatic arsenic poisoning is not often seen in occupational exposure settings. Attempted homicide and deliberate long-term poisoning have resulted in chronic toxicity. Skin pigmentation changes, palmar and plantar hyperkeratoses, gastrointestinal symptoms, anemia, and liver disease are common. Noncirrhotic portal hypertension with bleeding esophageal varices, splenomegaly, and hypersplenism may occur. A metallic taste, gastrointestinal disturbances, and Mee's lines may be seen. Bone marrow depression is common. 'Blackfoot disease' has been associated with arsenic-contaminated drinking water in Taiwan; Raynaud's phenomenon and acrocyanosis also may occur. Large numbers of persons in areas of India, Pakistan, and several other countries have been chronically poisoned from naturally occurring arsenic in ground water. Toxic delirium and encephalopathy can be present. CCA-treated wood (chromated copper arsenate) is not a health risk unless burned in fireplaces or woodstoves. Peripheral neuropathy may also occur. Workplace exposure or chronic ingestion of arsenic-contaminated water or arsenical medications is associated with development of skin, lung, and other cancers. Treatment may incklude the use of chelating agents such as dimercaprol (BAL), dimercaptosuccinic acid (DMSA), and dimercaptopanesulfonic acid (DMPS).
Topics: Arsenates; Arsenic; Arsenic Poisoning; Chronic Disease; Developing Countries; Environmental Exposure; Humans; Occupational Exposure
PubMed: 11869818
DOI: 10.1016/s0378-4274(01)00534-3 -
Journal of Bacteriology May 1992The ars operon of the resistance plasmid R773 was found to produce moderate levels of resistance to tellurite. A MIC of 64 micrograms of TeO3(2-) per ml was found for...
The ars operon of the resistance plasmid R773 was found to produce moderate levels of resistance to tellurite. A MIC of 64 micrograms of TeO3(2-) per ml was found for Escherichia coli cells harboring plasmids which contained all three of the structural genes (arsA, arsB, and arsC) of the anion-translocating ATPase. MICs specified by plasmids carrying only one or two structural elements or the cloning vector alone were 2 to 4 micrograms/ml. The rate of TeO3(2-) uptake was found to be on the order of 55% less for cultures containing the resistance plasmids.
Topics: Adenosine Triphosphatases; Antimony; Arsenates; Arsenic; Arsenic Poisoning; Arsenicals; Arsenite Transporting ATPases; Arsenites; Drug Resistance, Microbial; Escherichia coli; Ion Pumps; Membrane Proteins; Multienzyme Complexes; R Factors; Tellurium
PubMed: 1533216
DOI: 10.1128/jb.174.9.3092-3094.1992 -
Molecular Microbiology Jun 2016Microorganisms have evolved various mechanisms to detoxify arsenic, an ubiquitous environmental toxin. Known mechanisms include arsenite efflux, arsenate reduction...
Microorganisms have evolved various mechanisms to detoxify arsenic, an ubiquitous environmental toxin. Known mechanisms include arsenite efflux, arsenate reduction followed by arsenite efflux and arsenite methylation. In this issue, Chen et al. describe a novel mechanism for arsenate detoxification via synergistic interaction of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and a major facilitator superfamily protein (ArsJ). They propose that GAPDH catalyzes the formation of 1-arseno-3-phosphoglycerate, which is then extruded out of the cell by ArsJ. The significance of this pathway and questions for further research are discussed.
Topics: Arsenates; Arsenic; Arsenites; Glyceraldehyde-3-Phosphate Dehydrogenases
PubMed: 27072877
DOI: 10.1111/mmi.13395 -
The Science of the Total Environment Jan 2022Elevated arsenic (As) in soil is of public concern due to the carcinogenicity. Phosphorus (P) strongly influences the adsorption, absorption, transport, and... (Review)
Review
Elevated arsenic (As) in soil is of public concern due to the carcinogenicity. Phosphorus (P) strongly influences the adsorption, absorption, transport, and transformation of As in the soil and in organisms due to the similarity of the chemical properties of P and As. In soil, P, particularly inorganic P, can release soil-retained As (mostly arsenate) by competing for adsorption sites. In plant and microbial systems, P usually reduces As (mainly arsenate) uptake and affects As biotransformation by competing for As transporters. The intensity and pattern of PAs interaction are highly dependent on the forms of As and P, and strongly influenced by various biotic and abiotic factors. An understanding of the PAs interaction in 'soil-plant-microbe' systems is of great value to prevent soil As from entering the human food chain. Here, we review PAs interactions and the main influential factors in soil, plant, and microbial subsystems and their effects on the As release, absorption, transformation, and transport in the 'soil-plant-microbe' system. We also analyze the application potential of P fertilization as a control for As pollution and suggest the research directions that need to be followed in the future.
Topics: Arsenates; Arsenic; Environmental Pollution; Humans; Phosphorus; Plants; Soil; Soil Pollutants
PubMed: 34464787
DOI: 10.1016/j.scitotenv.2021.149796 -
Journal of General Microbiology Mar 1989Twenty-six wild-type Streptomyces strains tested for resistance to arsenate, arsenite and antimony(III) could be divided into four groups: those resistant only to...
Twenty-six wild-type Streptomyces strains tested for resistance to arsenate, arsenite and antimony(III) could be divided into four groups: those resistant only to arsenite (3) or to arsenate (2) and those resistant (8) or sensitive (13) to both heavy metals. All strains were sensitive to antimony. The structural genes for the ars operon of Escherichia coli were subcloned into various Streptomyces plasmid vectors. The expression of the whole ars operon in streptomycetes may be strain-specific and occurred only from low-copy-number plasmids. The arsC gene product could be expressed from high-copy plasmids and conferred arsenate resistance to both E. coli and Streptomyces species. The ars operon expressed in S. lividans and the arsC gene expressed in S. noursei did not render the synthesis of undecylprodigiosin and nourseothricin, respectively, phosphate-resistant. In addition in wild-type strains of Streptomyces phosphate sensitivity of antibiotic biosynthesis did not show strong correlation with resistance of growth to arsenicals.
Topics: Anti-Bacterial Agents; Antimony; Arsenates; Arsenic; Arsenicals; Arsenites; Drug Resistance, Microbial; Genes; Operon; Phosphates; R Factors; Streptomyces
PubMed: 2621441
DOI: 10.1099/00221287-135-3-583 -
Salud Publica de Mexico 2020To describe interindividual metabolism variations and sociodemographic characteristics associated to urinary arsenic, and to estimate the arsenic contamination in water...
OBJECTIVE
To describe interindividual metabolism variations and sociodemographic characteristics associated to urinary arsenic, and to estimate the arsenic contamination in water from urinary total arsenic (TAs).
MATERIALS AND METHODS
Women (n=1 028) from northern Mexico were interviewed about their sociodemographic characteristics and their urinary concentrations of arsenic species were measured by liquid chromatography. Inorganic arsenic (iAs) in water was estimated from urinary TAs.
RESULTS
Women were 20-88 years old. TAs in urine ranged from p10=3.41 to p90=56.93 μg/L; 74% of women had levels >6.4 μg/L. iAs in water varied from p10=3.04 to p90=202.12 μg/L; 65% of women had concentrations >10 μg/L, and 41%, concentrations >25 μg/L. Large variations in iAs metabolism were observed. TAs was significantly negatively associated with age and schooling, and positively with the state of residence.
CONCLUSIONS
Exposure to iAs is an environmental problem in Mexico. Individual variations in metabolism are a challenge to design prevention and control programs.
Topics: Adult; Aged; Aged, 80 and over; Arsenates; Arsenic; Arsenicals; Cacodylic Acid; Case-Control Studies; Chromatography, Liquid; Environmental Exposure; Female; Herbicides; Humans; Mexico; Middle Aged; Socioeconomic Factors; Water Pollutants, Chemical; Young Adult
PubMed: 32520484
DOI: 10.21149/11085 -
Canadian Journal of Microbiology Oct 2011Contamination of the environment with heavy metals has increased drastically over the last few decades. The heavy metals that are toxic include mercury, cadmium,... (Review)
Review
Contamination of the environment with heavy metals has increased drastically over the last few decades. The heavy metals that are toxic include mercury, cadmium, arsenic, and selenium. Of these heavy metals, arsenic is one of the most important global environmental pollutants and is a persistent bioaccumulative carcinogen. It is a toxic metalloid that exists in two major inorganic forms: arsenate and arsenite. Arsenite disrupts enzymatic functions in cells, while arsenate behaves as a phosphate analog and interferes with phosphate uptake and utilization. Despite its toxicity, arsenic may be actively sequestered in plant and animal tissues. Various microbes interact with this metal and have shown resistance to arsenic exposure, and they appear to possess the ars operon for arsenic resistance consisting of three to five genes, i.e., arsRBC or arsRDABC, organized into a single transcriptional unit; some microbes even use it for respiration. Microbial interactions with metals may have several implications for the environment. Microbes may play a role in cycling of toxic heavy metals and in remediation of metal-contaminated sites. There is a correlation between tolerance to heavy metals and antibiotic resistance, a global problem currently threatening the treatment of infections in plants, animals, and humans. The purpose of this review is to highlight the nature and role of toxic arsenic in bacterial systems and to discuss the various genes responsible for this heavy-metal resistance in nature and the mechanisms to detoxify this element.
Topics: Animals; Arsenates; Arsenic; Arsenites; Bacteria; Carcinogens, Environmental; Drug Resistance, Bacterial; Environmental Pollutants; Humans; Metals, Heavy; Plants
PubMed: 21936668
DOI: 10.1139/w11-062