title: Associating growth-phase-related changes in the proteome of Acinetobacter baumannii with increased resistance to oxidative stress.
abstract: Acinetobacter baumannii is an opportunistic pathogen that has been associated with severe infections and outbreaks in hospitals. At present, very little is known about the biology of this bacterium, particularly as regards mechanisms of adaptation, persistence and virulence. To investigate the growth phase-dependent regulation of proteins in this microorganism, we analyzed the proteomic pattern of A. baumannii ATCC 17978 at different stages of in vitro growth. In this study, proteomics analyses were conducted using 2-DE and MALDI-TOF/TOF complemented by iTRAQ LC-MS/MS. Here we have identified 107 differentially expressed proteins. We highlight the induction of proteins associated with signaling, putative virulence factors and response to stress (including oxidative stress). We also present evidence that ROS (O(2)(-) and OH(-)) and RNI (ONOO(-)) accumulate during late stages of growth. Further assays demonstrated that stationary cells survive at high concentrations of H(2)O(2) (30 mM), the O(2)(-) donor menadione (500 muM) or the NO donor sodium nitroprusside (1 mM), and showed a higher survival rate against several bactericidal antibiotics. The growth phase-dependent changes observed in the A. baumannii proteome are discussed within a context of adaptive biological responses, including those related to ROS and RNI stress.
authors.affiliation: Servicio de Microbiologia-INIBIC, Complejo Hospitalario Universitario La Coruna, As Xubias s/n, La Coruna, Spain.
authors.forename: Nelson C
authors.initials: NC
authors.lastname: Soares
authors.forename: Maria P
authors.initials: MP
authors.lastname: Cabral
authors.forename: Carmen
authors.initials: C
authors.lastname: Gayoso
authors.forename: Susana
authors.initials: S
authors.lastname: Mallo
authors.forename: Patricia
authors.initials: P
authors.lastname: Rodriguez-Velo
authors.forename: Esteban
authors.initials: E
authors.lastname: Fernández-Moreira
authors.forename: Germán
authors.initials: G
authors.lastname: Bou
mesh_terms: D040981:Acinetobacter baumannii / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism*; D000704:Analysis of Variance; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins / Q000145:classification / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007553:Isotope Labeling; D050296:Microbial Viability; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D020543:Proteome / Q000378:metabolism*; D040901:Proteomics / Q000379:methods*; D026361:Reactive Nitrogen Species / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D020543:Proteome; D026361:Reactive Nitrogen Species; D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide