title: Computational modeling and preliminary iroN, fepA, and cirA gene expression in Salmonella Enteritidis under iron-deficiency-induced conditions.
abstract: Salmonellosis outbreaks in Europe, the United States, and Latin America have been associated with contaminated food derivatives including meat from the poultry industry. Salmonella grown under iron-limiting conditions has the capability to increase concentration of several iron-regulated outer-membrane proteins to augment the acquisition of the metal. These proteins have been proved to have immunogenic properties. Our aim was to increase the relative expression of iroN, fepA, and cirA in Salmonella Enteritidis domestic strain. Furthermore, we proposed a 3-dimensional structure model for each protein to predict and locate antigenic peptides. Our eventual objective is to produce an effective vaccine against regional avian salmonellosis. Two simple factorial designs were carried out to discriminate between 2 nitrogen sources and determine chelating-agent addition timing to augment relative gene expression. Two antigenic peptides located at the external face of each protein and 2 typical domains of iron-regulated outer-membrane proteins, plug and TonB-dep-Rec, were identified from the 3-dimensional models. Tryptone was selected as the best nitrogen source based on growth rate (μx = 0.36 h(-1)) and biomass productivity (Px = 0.9 g•h(-1)•L(-1)) as determined by a general factorial design. Optimum timing for chelating agent addition was in the middle of the log phase, which allowed relative expressions at 4 h of culture. Increase in iroN, fepA, and cirA relative expression was favored by the length of log phase and the addition of chelating agent, which decreased chelating toxicity and enhanced cell growth rate.
authors.affiliation: Corporación CorpoGen, 110231, Bogotá, DC, Colombia.
authors.forename: Lina J
authors.initials: LJ
authors.lastname: Zárate-Bonilla
authors.forename: Patricia
authors.initials: P
authors.lastname: Del Portillo
authors.forename: Homero
authors.initials: H
authors.lastname: Sáenz-Suárez
authors.forename: Janneth
authors.initials: J
authors.lastname: Gonzáles-Santos
authors.forename: George E
authors.initials: GE
authors.lastname: Barreto-Sampaio
authors.forename: Raúl A
authors.initials: RA
authors.lastname: Poutou-Piñales
authors.forename: Andrés Felipe
authors.initials: AF
authors.lastname: Rey
authors.forename: Jairo Guillermo
authors.initials: JG
authors.lastname: Rey
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002614:Chelating Agents / Q000494:pharmacology; D003198:Computer Simulation; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects*; D007501:Iron / Q000494:pharmacology*; D008954:Models, Biological; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009584:Nitrogen / Q000378:metabolism; D011487:Protein Conformation; D012477:Salmonella enteritidis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D002614:Chelating Agents; D007501:Iron; D009584:Nitrogen
keywords: Salmonella Enteritidis; cirA; computer modeling; fepA; iroN; iron deficiency condition; iron-regulated outer-membrane protein