title: Bacterial toxicity of potassium tellurite: unveiling an ancient enigma.
abstract: Biochemical, genetic, enzymatic and molecular approaches were used to demonstrate, for the first time, that tellurite (TeO(3) (2-)) toxicity in E. coli involves superoxide formation. This radical is derived, at least in part, from enzymatic TeO(3) (2-) reduction. This conclusion is supported by the following observations made in K(2)TeO(3)-treated E. coli BW25113: i) induction of the ibpA gene encoding for the small heat shock protein IbpA, which has been associated with resistance to superoxide, ii) increase of cytoplasmic reactive oxygen species (ROS) as determined with ROS-specific probe 2'7'-dichlorodihydrofluorescein diacetate (H(2)DCFDA), iii) increase of carbonyl content in cellular proteins, iv) increase in the generation of thiobarbituric acid-reactive substances (TBARs), v) inactivation of oxidative stress-sensitive [Fe-S] enzymes such as aconitase, vi) increase of superoxide dismutase (SOD) activity, vii) increase of sodA, sodB and soxS mRNA transcription, and viii) generation of superoxide radical during in vitro enzymatic reduction of potassium tellurite.
authors.affiliation: Laboratorio de Microbiología Molecular, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile.
authors.forename: José M
authors.initials: JM
authors.lastname: Pérez
authors.forename: Iván L
authors.initials: IL
authors.lastname: Calderón
authors.forename: Felipe A
authors.initials: FA
authors.lastname: Arenas
authors.forename: Derie E
authors.initials: DE
authors.lastname: Fuentes
authors.forename: Gonzalo A
authors.initials: GA
authors.lastname: Pradenas
authors.forename: Eugenia L
authors.initials: EL
authors.lastname: Fuentes
authors.forename: Juan M
authors.initials: JM
authors.lastname: Sandoval
authors.forename: Miguel E
authors.initials: ME
authors.lastname: Castro
authors.forename: Alex O
authors.initials: AO
authors.lastname: Elías
authors.forename: Claudio C
authors.initials: CC
authors.lastname: Vásquez
mesh_terms: D000154:Aconitate Hydratase / Q000037:antagonists & inhibitors; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics; D057773:Cold Shock Proteins and Peptides; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics; D005452:Fluoresceins / Q000032:analysis; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D006360:Heat-Shock Proteins / Q000096:biosynthesis / Q000235:genetics; D010084:Oxidation-Reduction; D012329:RNA, Bacterial / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis; D017382:Reactive Oxygen Species / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics; D013482:Superoxide Dismutase / Q000096:biosynthesis / Q000235:genetics; D013481:Superoxides / Q000378:metabolism; D013691:Tellurium / Q000633:toxicity*; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis; D015534:Trans-Activators / Q000096:biosynthesis / Q000235:genetics
chemical_list: C110400:2',7'-dichlorodihydrofluorescein diacetate; D001426:Bacterial Proteins; D057773:Cold Shock Proteins and Peptides; C498192:CspA protein, E coli; D029968:Escherichia coli Proteins; D005452:Fluoresceins; D006360:Heat-Shock Proteins; C097578:IbpA protein, E coli; D012329:RNA, Bacterial; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D011993:Recombinant Fusion Proteins; D017392:Thiobarbituric Acid Reactive Substances; D015534:Trans-Activators; D013481:Superoxides; C070725:SoxS protein, E coli; C026899:potassium tellurate(IV); C095500:SodA protein, Bacteria; C087504:SodB protein, Bacteria; D013482:Superoxide Dismutase; D000154:Aconitate Hydratase; D013691:Tellurium