title: Functional analysis of an feoB mutant in Clostridium perfringens strain 13.
abstract: Bacterial pathogens have adopted numerous mechanisms for acquiring iron from host proteins during an infection, including the direct acquisition of ferric iron from heme-associated proteins or from iron-scavenging siderophores. Ferric iron then is transported into the cytosol, where it can be utilized by the bacterial pathogen. Under anaerobic conditions bacteria can also transport ferrous iron using the transmembrane complex FeoAB, but little is known about iron transport systems in anaerobic bacteria such as the pathogenic clostridia. In this study we sought to characterize the iron acquisition process in Clostridium perfringens. Bioinformatic analysis of the Clostridium perfringens strain 13 genome sequence revealed that it has seven potential iron acquisition systems: three siderophore-mediated systems, one ferric citrate uptake system, two heme-associated acquisition systems and one ferrous iron uptake system (FeoAB). The relative level of expression of these systems was determined using quantitative real-time RT-PCR assays that were specific for one gene from each system. Each of these genes was expressed, with the feoAB genes generating the most abundant iron-uptake related transcripts. To further examine the role of this system in the growth of C. perfringens, insertional inactivation was used to isolate a chromosomal feoB mutant. Growth of this mutant in the presence and absence of iron revealed that it had altered growth properties and a markedly reduced total iron and manganese content compared to the wild type; effects that were reversed upon complementation with the wild-type feoB gene. These studies suggest that under anaerobic conditions FeoB is the major protein required for the uptake of iron into the cell and that it may play an important role in the pathogenesis of C. perfringens infections.
authors.affiliation: Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Vic 3800, Australia.
authors.forename: Milena M
authors.initials: MM
authors.lastname: Awad
authors.affiliation: Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Vic 3800, Australia.
authors.forename: Jackie K
authors.initials: JK
authors.lastname: Cheung
authors.affiliation: Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Vic 3800, Australia.
authors.forename: Joanne E
authors.initials: JE
authors.lastname: Tan
authors.affiliation: School of Molecular and Microbial Sciences, University of Queensland, St Lucia, Qld 4067, Australia.
authors.forename: Alastair G
authors.initials: AG
authors.lastname: McEwan
authors.affiliation: Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Vic 3800, Australia.
authors.forename: Dena
authors.initials: D
authors.lastname: Lyras
authors.affiliation: Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Vic 3800, Australia. Electronic address: julian.rood@monash.edu.
authors.forename: Julian I
authors.initials: JI
authors.lastname: Rood
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001427:Bacterial Toxins / Q000096:biosynthesis; D003016:Clostridium perfringens / Q000235:genetics* / Q000378:metabolism; D007501:Iron / Q000378:metabolism; D008345:Manganese / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D026901:Membrane Transport Proteins; D008345:Manganese; D007501:Iron
keywords: Bacterial growth; Clostridium perfringens; Iron uptake; Manganese; Toxin