New mechanisms of bacterial arsenic resistance

Yang, Hung‐Chi; Rosen, Barry P.

doi:10.1016/j.bj.2015.08.003

Cited by 156 publications

(119 citation statements)

References 65 publications

(92 reference statements)

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“…The C‐As bond is quite stable. The specific biochemical pathway(s) involved remain to be identified, although at present it appears that arsenic methylation (via ArsM) (Yang and Rosen, ) is an essential first step because methylated pentavalent arsenicals are typically a feature of As‐C containing carbon compounds such as arsenosugars and arsenolipids (Dembitsky and Levitsky, ). Cellular localization of As in our A. tumefaciens strains shows incorporation into lipids (Fig.…”

Section: Discussionmentioning

confidence: 99%

Phosphate starvation response controls genes required to synthesize the phosphate analog arsenate

Wang

Kang

Alowaifeer

et al. 2018

Environmental Microbiology

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Environmental arsenic poisoning affects roughly 200 million people worldwide. The toxicity and mobility of arsenic in the environment is significantly influenced by microbial redox reactions, with arsenite (As ) being more toxic than arsenate (As ). Microbial oxidation of As to As is known to be regulated by the AioXSR signal transduction system and viewed to function for detoxification or energy generation. Here, we show that As oxidation is ultimately regulated by the phosphate starvation response (PSR), requiring the sensor kinase PhoR for expression of the As oxidase structural genes aioBA. The PhoRB and AioSR signal transduction systems are capable of transphosphorylation cross-talk, closely integrating As oxidation with the PSR. Further, under PSR conditions, As significantly extends bacterial growth and accumulates in the lipid fraction to the apparent exclusion of phosphorus. This could spare phosphorus for nucleic acid synthesis or triphosphate metabolism wherein unstable arsenic esters are not tolerated, thereby enhancing cell survival potential. We conclude that As oxidation is logically part of the bacterial PSR, enabling the synthesis of the phosphate analog As to replace phosphorus in specific biomolecules or to synthesize other molecules capable of a similar function, although not for total replacement of cellular phosphate.

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Section: Discussionmentioning

confidence: 99%

Phosphate starvation response controls genes required to synthesize the phosphate analog arsenate

Wang

Kang

Alowaifeer

et al. 2018

Environmental Microbiology

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“…Soil microbial such as Pseudomonas putida and Burkholderia MR1 reduce MAs(V) to MAs(III), which is subsequently degraded to the more mobile As(III) by other members of microbial communities such as Bacillus MD1. We propose that MAs(III) functions as an antibiotic to kill off other members of the microbial communities (Li et al ., ; Yang and Rosen, ). In response to this environmental pressure, other bacteria have evolved mechanisms to detoxify MAs(III).…”

Section: Introductionmentioning

confidence: 99%

A novel MAs(III)‐selective ArsR transcriptional repressor

Chen

Nadar

Rosen

2017

Molecular Microbiology

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Microbial expression of genes for resistance to heavy metals and metalloids is usually transcriptionally regulated by the toxic ions themselves. Arsenic is a ubiquitous, naturally occurring toxic metalloid widely distributed in soil and groundwater. Microbes biotransform both arsenate (As(V)) and arsenite (As(III)) into more toxic methylated metabolites methylarsenite (MAs(III)) and dimethylarsenite (DMAs(III)). Environmental arsenic is sensed by members of the ArsR/SmtB family. The arsR gene is autoregulated and is typically part of an operon that contains other ars genes involved in arsenic detoxification. To date every identified ArsR is regulated by inorganic As(III). Here we described a novel ArsR from Shewanella putrefaciens selective for MAs(III). SpArsR orthologs control expression of two MAs(III) resistance genes, arsP that encodes the ArsP MAs(III) efflux permease, and arsH encoding the ArsH MAs(III) oxidase. SpArsR has two conversed cysteine residues, Cys101 and Cys102. Mutation of either resulted in loss of MAs(III) binding, indicating that they form an MAs(III) binding site. SpArsR can be converted into an As(III)-responsive repressor by introduction of an additional cysteine that allows for 3-coordinate As(III) binding. Our results indicate that SpArsR evolved selectivity for MAs(III) over As(III) in order to control expression of genes for MAs(III) detoxification.

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“…It was interesting that the MICs for As(III) and As(V) were greater in mineral (MES) medium than those in LB for most isolates, and several isolates even presented MICs more than 100 mM. To explain this situation, it could be estimated that the endophytes may have developed special mechanism to adapt the local environment, such as metabolize arsenic as substrate for respiration (Stolz et al 2006), arsenite oxidation, arsenate reduction, methylation and demethylation of arsenic, organic acids production, ligand production (siderophores), membrane transporters, biosorption, adsorption and compartmentalization (Nair et al 2007, Mailloux et al 2009, Ahsan et al 2011, Kruger et al 2013, Prasad et al 2013, Yang and Rosen 2016. Further study is worthy for clarifying the mechanisms in our isolates.…”

Section: Discussionmentioning

confidence: 99%

Cultivable endophytic bacteria from heavy metal(loid)-tolerant plants

Román‐Ponce¹,

Ramos-Garza²,

Vásquez-Murrieta³

et al. 2016

Arch Microbiol

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To evaluate the interactions among endophytes, plants and heavy metal/arsenic contamination, root endophytic bacteria of Prosopis laevigata (Humb and Bonpl. ex Willd) and Sphaeralcea angustifolia grown in a heavy metal(loid)-contaminated zone in San Luis Potosi, Mexico, were isolated and characterized. Greater abundance and species richness were found in Prosopis than in Sphaeralcea and in the nutrient Pb-Zn-rich hill than in the poor nutrient and As-Cu-rich mine tailing. The 25 species identified among the 60 isolates formed three groups in the correspondence analysis, relating to Prosopis/hill (11 species), Prosopis/mine tailing (4 species) and Sphaeralcea/hill (4 species), with six species ungrouped. Most of the isolates showed high or extremely high resistance to arsenic, such as ≥100 mM for As(V) and ≥20 mM for As(III), in mineral medium. These results demonstrated that the abundance and community composition of root endophytic bacteria were strongly affected by the concentration and type of the heavy metals and metalloids (arsenic), as well as the plant species.

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New mechanisms of bacterial arsenic resistance

Cited by 156 publications

References 65 publications

Phosphate starvation response controls genes required to synthesize the phosphate analog arsenate

Phosphate starvation response controls genes required to synthesize the phosphate analog arsenate

A novel MAs(III)‐selective ArsR transcriptional repressor

Cultivable endophytic bacteria from heavy metal(loid)-tolerant plants

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