title: Engineered coryneform bacteria as a bio-tool for arsenic remediation.
abstract: Despite current remediation efforts, arsenic contamination in water sources is still a major health problem, highlighting the need for new approaches. In this work, strains of the nonpathogenic and highly arsenic-resistant bacterium Corynebacterium glutamicum were used as inexpensive tools to accumulate inorganic arsenic, either as arsenate (As(V)) or arsenite (As(III)) species. The assays made use of "resting cells" from these strains, which were assessed under well-established conditions and compared with C. glutamicum background controls. The two mutant As(V)-accumulating strains were those used in a previously published study: (i) ArsC1/C2, in which the gene/s encoding the mycothiol-dependent arsenate reductases is/are disrupted, and (ii) MshA/C mutants unable to produce mycothiol, the low molecular weight thiol essential for arsenate reduction. The As(III)-accumulating strains were either those lacking the arsenite permease activities (Acr3-1 and Acr3-2) needed in As(III) release or recombinant strains overexpressing the aquaglyceroporin genes (glpF) from Corynebacterium diphtheriae or Streptomyces coelicolor, to improve As(III) uptake. Both genetically modified strains accumulated 30-fold more As(V) and 15-fold more As(III) than the controls. The arsenic resistance of the modified strains was inversely proportional to their metal accumulation ability. Our results provide the basis for investigations into the use of these modified C. glutamicum strains as a new bio-tool in arsenic remediation efforts.
authors.affiliation: Departament of Molecular Biology, Area of Microbiology, Faculty of Biology-Environmental Sciences, University of León, León, 24071, Spain.
authors.forename: Almudena F
authors.initials: AF
authors.lastname: Villadangos
authors.forename: Efrén
authors.initials: E
authors.lastname: Ordóñez
authors.forename: Brandán
authors.initials: B
authors.lastname: Pedre
authors.forename: Joris
authors.initials: J
authors.lastname: Messens
authors.forename: Jose A
authors.initials: JA
authors.lastname: Gil
authors.forename: Luis M
authors.initials: LM
authors.lastname: Mateos
mesh_terms: D001151:Arsenic / Q000378:metabolism*; D003353:Corynebacterium diphtheriae / Q000201:enzymology / Q000235:genetics; D048230:Corynebacterium glutamicum / Q000235:genetics* / Q000378:metabolism*; D024881:Drug Resistance, Bacterial; D052918:Environmental Restoration and Remediation / Q000379:methods*; D060847:Metabolic Engineering; D048372:Streptomyces coelicolor / Q000201:enzymology / Q000235:genetics; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D014874:Water Pollutants, Chemical; D001151:Arsenic