title: Arsenate transport and reduction in the hyper-tolerant fungus Aspergillus sp. P37.
abstract: Aspergillus sp. P37 is able to grow at arsenate concentrations of 0.2 M--more than 20-fold higher than that withstood by reference microorganisms such Escherichia coli, Saccharomyces cerevisiae and Aspergillus nidulans. This paper examines the transport of arsenate and phosphate and the reduction of arsenate in Aspergillus sp. P37. These properties were compared with the corresponding properties of the archetype strain Aspergillus nidulans TS1. Both uptake and efflux of arsenate were inhibited by carbonyl cyanide-p-trifluoromethoxyphenylhydrazone, suggesting that the transport system(s) is(are) membrane-potential dependent. As uptake of arsenate and phosphate are higher in Aspergillus sp. P37 than in A. nidulans, the increase in arsenate resistance cannot be accounted for by a change in uptake. Cells of both strains loaded with arsenic slowly released the oxyanion. Speciation of the arsenic in the medium showed an enhanced level of arsenate reduction in Aspergillus sp. P37. These data suggest that increased arsenate reduction is at least in part responsible for the hyper-tolerant phenotype of this fungus.
authors.affiliation: Centro Nacional de Biotecnología-CSIC, Campus UAM-Cantoblanco, Madrid 28049, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Cánovas
authors.forename: Rita
authors.initials: R
authors.lastname: Mukhopadhyay
authors.forename: Barry P
authors.initials: BP
authors.lastname: Rosen
authors.forename: Víctor
authors.initials: V
authors.lastname: de Lorenzo
mesh_terms: D001149:Arsenates / Q000378:metabolism* / Q000494:pharmacology; D001151:Arsenic / Q000378:metabolism; D001230:Aspergillus / Q000187:drug effects / Q000378:metabolism*; D001692:Biological Transport / Q000502:physiology; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D025141:Drug Resistance, Fungal; D010084:Oxidation-Reduction; D010710:Phosphates / Q000378:metabolism; D014475:Uncoupling Agents / Q000494:pharmacology; D014634:Valinomycin / Q000494:pharmacology; D014700:Verapamil / Q000494:pharmacology
chemical_list: D001149:Arsenates; D010710:Phosphates; D014475:Uncoupling Agents; D014634:Valinomycin; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; D014700:Verapamil; D001151:Arsenic