title: Cytochrome d but not cytochrome o rescues the toluidine blue growth sensitivity of arc mutants of Escherichia coli.
abstract: The Arc (anoxic redox control) two-component signal transduction system, consisting of the ArcB sensor kinase and the ArcA response regulator, allows adaptive responses of Escherichia coli to changes of O(2) availability. The arcA gene was previously known as the dye gene because null mutants were growth sensitive to the photosensitizer redox dyes toluidine blue and methylene blue, a phenotype whose molecular basis still remains elusive. In this study we report that the toluidine blue O (TBO) effect on the arc mutants is light independent and observed only during aerobic growth conditions. Moreover, 16 suppressor mutants with restored growth were generated and analyzed. Thirteen of those possessed insertion elements upstream of the cydAB operon, rendering its expression ArcA independent. Also, it was found that, in contrast to cythocrome d, cythocrome o was not able to confer toluidine blue resistance to arc mutants, thereby representing an intriguing difference between the two terminal oxidases. Finally, a mechanism for TBO sensitivity and resistance is discussed.
authors.affiliation: Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510 Mexico, Mexico.
authors.forename: Adrian F
authors.initials: AF
authors.lastname: Alvarez
authors.forename: Roxana
authors.initials: R
authors.lastname: Malpica
authors.forename: Martha
authors.initials: M
authors.lastname: Contreras
authors.forename: Edgardo
authors.initials: E
authors.lastname: Escamilla
authors.forename: Dimitris
authors.initials: D
authors.lastname: Georgellis
mesh_terms: D000693:Anaerobiosis; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D002338:Carotenoids / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D004396:Coloring Agents / Q000494:pharmacology; D003573:Cytochrome b Group / Q000235:genetics / Q000378:metabolism*; D017937:Cytochrome d Group / Q000235:genetics / Q000378:metabolism*; D003580:Cytochromes / Q000235:genetics / Q000378:metabolism*; D003624:Darkness; D045222:Electron Transport Chain Complex Proteins / Q000235:genetics; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects; D005947:Glucose / Q000494:pharmacology; D008027:Light; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010088:Oxidoreductases / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D013482:Superoxide Dismutase / Q000378:metabolism; D014048:Tolonium Chloride / Q000494:pharmacology*
chemical_list: D001425:Bacterial Outer Membrane Proteins; D004396:Coloring Agents; D003573:Cytochrome b Group; D003580:Cytochromes; D045222:Electron Transport Chain Complex Proteins; D029968:Escherichia coli Proteins; D017382:Reactive Oxygen Species; D012097:Repressor Proteins; C041610:arcA protein, E coli; D014048:Tolonium Chloride; D002338:Carotenoids; D017937:Cytochrome d Group; C017168:cytochrome bo, E coli; D010088:Oxidoreductases; D002374:Catalase; D013482:Superoxide Dismutase; C040077:cytochrome bd terminal oxidase complex, E coli; D005947:Glucose