title: Escherichia coli response to uranyl exposure at low pH and associated protein regulations.
abstract: Better understanding of uranyl toxicity in bacteria is necessary to optimize strains for bioremediation purposes or for using bacteria as biodetectors for bioavailable uranyl. In this study, after different steps of optimization, Escherichia coli cells were exposed to uranyl at low pH to minimize uranyl precipitation and to increase its bioavailability. Bacteria were adapted to mid acidic pH before exposure to 50 or 80 µM uranyl acetate for two hours at pH≈3. To evaluate the impact of uranium, growth in these conditions were compared and the same rates of cells survival were observed in control and uranyl exposed cultures. Additionally, this impact was analyzed by two-dimensional differential gel electrophoresis proteomics to discover protein actors specifically present or accumulated in contact with uranium.Exposure to uranium resulted in differential accumulation of proteins associated with oxidative stress and in the accumulation of the NADH/quinone oxidoreductase WrbA. This FMN dependent protein performs obligate two-electron reduction of quinones, and may be involved in cells response to oxidative stress. Interestingly, this WrbA protein presents similarities with the chromate reductase from E. coli, which was shown to reduce uranyl in vitro.
authors.affiliation: CEA, DSV, IBEB, Commissariat à l'Energie Atomique, Laboratoire des Interactions Protéine-Métal, Saint-Paul-lez-Durance, France ; CNRS, UMR Biologie Végétale et Microbiologie Environnementales 7265, Saint-Paul-lez-Durance, France ; Université d'Aix-Marseille, Saint-Paul-lez-Durance, France.
authors.forename: Arbia
authors.initials: A
authors.lastname: Khemiri
authors.affiliation: UMR E3 CEA-Université Joseph Fourier, Service de Chimie Inorganique et Biologique, Laboratoire Lésions des Acides Nucléiques (LAN), Grenoble, France.
authors.forename: Marie
authors.initials: M
authors.lastname: Carrière
authors.affiliation: CEA, DSV, IBEB, Commissariat à l'Energie Atomique, Laboratoire des Interactions Protéine-Métal, Saint-Paul-lez-Durance, France ; CNRS, UMR Biologie Végétale et Microbiologie Environnementales 7265, Saint-Paul-lez-Durance, France ; Université d'Aix-Marseille, Saint-Paul-lez-Durance, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Bremond
authors.affiliation: UMR 6270 CNRS, Plateforme Protéomique PISSARO, IRIB -Université de Rouen, Mont Saint Aignan, France.
authors.forename: Mohamed Amine
authors.initials: MA
authors.lastname: Ben Mlouka
authors.affiliation: UMR 6270 CNRS, Plateforme Protéomique PISSARO, IRIB -Université de Rouen, Mont Saint Aignan, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Coquet
authors.affiliation: ESRF-CRG-FAME beamline, Polygone Scientifique Louis Néel, Grenoble, France ; Commissariat à l'Energie Atomique CEA, DSM, INAC, Laboratoire Nanostructure et Rayonnement Synchrotron, Grenoble, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Llorens
authors.affiliation: CEA, DSV, IBEB, Commissariat à l'Energie Atomique, Laboratoire des Interactions Protéine-Métal, Saint-Paul-lez-Durance, France ; CNRS, UMR Biologie Végétale et Microbiologie Environnementales 7265, Saint-Paul-lez-Durance, France ; Université d'Aix-Marseille, Saint-Paul-lez-Durance, France.
authors.forename: Virginie
authors.initials: V
authors.lastname: Chapon
authors.affiliation: UMR 6270 CNRS, Plateforme Protéomique PISSARO, IRIB -Université de Rouen, Mont Saint Aignan, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Jouenne
authors.affiliation: UMR 6270 CNRS, Plateforme Protéomique PISSARO, IRIB -Université de Rouen, Mont Saint Aignan, France.
authors.forename: Pascal
authors.initials: P
authors.lastname: Cosette
authors.affiliation: CEA, DSV, IBEB, Commissariat à l'Energie Atomique, Laboratoire des Interactions Protéine-Métal, Saint-Paul-lez-Durance, France ; CNRS, UMR Biologie Végétale et Microbiologie Environnementales 7265, Saint-Paul-lez-Durance, France ; Université d'Aix-Marseille, Saint-Paul-lez-Durance, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Berthomieu
mesh_terms: D001673:Biodegradation, Environmental; D001682:Biological Availability; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects*; D006863:Hydrogen-Ion Concentration; D007525:Isoelectric Focusing; D009942:Organometallic Compounds / Q000737:chemistry / Q000493:pharmacokinetics* / Q000633:toxicity*; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects; D025341:Principal Component Analysis; D040901:Proteomics; D053719:Tandem Mass Spectrometry; D056928:X-Ray Absorption Spectroscopy
chemical_list: D009942:Organometallic Compounds; C005460:uranyl acetate