title: Intracellular cyclic AMP concentration is decreased in Salmonella typhimurium fur mutants.
abstract: It is known that the Fur protein negatively regulates iron-uptake systems in different bacterial species, including Salmonella typhimurium. In this study it has been shown that the intracellular concentration of cyclic AMP (cAMP) is lower in a knockout S. typhimurium fur mutant than in the wild-type strain. According to this, the expression of two cAMP-regulated genes, such as pepE (encoding an alpha-aspartyl dipeptidase) and the Escherichia coli lac operon, is decreased in S. typhimurium fur cells in comparison with wild-type cells. Introduction of an additional mutation in cpdA, encoding a cyclic 3',5'-cAMP phosphodiesterase, recovers wild-type intracellular cAMP concentration in the S. typhimurium fur mutant. Likewise, expression of pepE and the E. coli lac operon was the same in the S. typhimurium fur cpdA double mutant and the wild-type strain. Moreover, these results also demonstrate that the S. typhimurium Fur protein positively regulates the expression of the flhD master operon governing the flagellar regulon. This positive control must be mediated by binding of the S. typhimurium Fur protein to the flhD promoter as indicated by the fact that this promoter tests positive in a Fur titration assay.
authors.affiliation: Department of Genetics and Microbiology, Universitat Autònoma de Barcelona1 and Centre de Recerca en Sanitat Animal (CReSA), Universitat Autònoma de Barcelona Institut de Recerca i Tecnologia Agroalimentària (UAB-IRTA)2, Bellaterra, 08193 Barcelona, Spain.
authors.forename: Susana
authors.initials: S
authors.lastname: Campoy
authors.affiliation: Department of Genetics and Microbiology, Universitat Autònoma de Barcelona1 and Centre de Recerca en Sanitat Animal (CReSA), Universitat Autònoma de Barcelona Institut de Recerca i Tecnologia Agroalimentària (UAB-IRTA)2, Bellaterra, 08193 Barcelona, Spain.
authors.forename: Mónica
authors.initials: M
authors.lastname: Jara
authors.affiliation: Department of Genetics and Microbiology, Universitat Autònoma de Barcelona1 and Centre de Recerca en Sanitat Animal (CReSA), Universitat Autònoma de Barcelona Institut de Recerca i Tecnologia Agroalimentària (UAB-IRTA)2, Bellaterra, 08193 Barcelona, Spain.
authors.forename: Núria
authors.initials: N
authors.lastname: Busquets
authors.affiliation: Department of Genetics and Microbiology, Universitat Autònoma de Barcelona1 and Centre de Recerca en Sanitat Animal (CReSA), Universitat Autònoma de Barcelona Institut de Recerca i Tecnologia Agroalimentària (UAB-IRTA)2, Bellaterra, 08193 Barcelona, Spain.
authors.forename: Ana M Pérez
authors.initials: AMP
authors.lastname: de Rozas
authors.affiliation: Department of Genetics and Microbiology, Universitat Autònoma de Barcelona1 and Centre de Recerca en Sanitat Animal (CReSA), Universitat Autònoma de Barcelona Institut de Recerca i Tecnologia Agroalimentària (UAB-IRTA)2, Bellaterra, 08193 Barcelona, Spain.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Badiola
authors.affiliation: Department of Genetics and Microbiology, Universitat Autònoma de Barcelona1 and Centre de Recerca en Sanitat Animal (CReSA), Universitat Autònoma de Barcelona Institut de Recerca i Tecnologia Agroalimentària (UAB-IRTA)2, Bellaterra, 08193 Barcelona, Spain.
authors.forename: Jordi
authors.initials: J
authors.lastname: Barbé
mesh_terms: D016282:Aspartic Acid Endopeptidases / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D000242:Cyclic AMP / Q000378:metabolism*; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D005656:Fungal Proteins; D015964:Gene Expression Regulation, Bacterial; D005838:Genotype; D007501:Iron / Q000378:metabolism; D007700:Kinetics; D007763:Lac Operon; D008969:Molecular Sequence Data; D010957:Plasmids; D012097:Repressor Proteins / Q000235:genetics*; D012486:Salmonella typhimurium / Q000235:genetics* / Q000378:metabolism*; D015534:Trans-Activators / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D017931:DNA Primers; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D005656:Fungal Proteins; D012097:Repressor Proteins; D015534:Trans-Activators; C068477:ferric uptake regulating proteins, bacterial; C090553:flhD protein, E coli; D000242:Cyclic AMP; D007501:Iron; D016282:Aspartic Acid Endopeptidases; C088855:PepE protein, Aspergillus niger