title: The pneumococcal response to oxidative stress includes a role for Rgg.
abstract: Streptococcus pneumoniae resides in the oxygen-rich environment of the upper respiratory tract, and therefore the ability to survive in the presence of oxygen is an important aspect of its in vivo survival. To investigate how S. pneumoniae adapts to oxygen, we determined the global gene expression profile of the micro-organism in aerobiosis and anaerobiosis. It was found that exposure to aerobiosis elevated the expression of 54 genes, while the expression of 15 genes was downregulated. Notably there were significant changes in putative genome plasticity and hypothetical genes. In addition, increased expression of rgg, a putative transcriptional regulator, was detected. To test the role of Rgg in the pneumococcal oxidative stress response, an isogenic mutant was constructed. It was found that the mutant was sensitive to oxygen and paraquat, but not to H(2)O(2). In addition, the absence of Rgg strongly reduced the biofilm-forming ability of an unencapsulated pneumococcus. Virulence studies showed that the median survival time of mice infected intranasally with the rgg mutant was significantly longer than that of the wild-type-infected group, and the animals infected with the mutant developed septicaemia later than those infected intranasally with the wild-type.
authors.affiliation: Department of Basic Sciences, Universidad De Monterrey, Monterrey 66238, Mexico.|Department of Infection, Immunity and Inflammation, University of Leicester, Leicester LE1 9HN, UK.
authors.forename: Magda E
authors.initials: ME
authors.lastname: Bortoni
authors.affiliation: Department of Infection, Immunity and Inflammation, University of Leicester, Leicester LE1 9HN, UK.
authors.forename: Vanessa S
authors.initials: VS
authors.lastname: Terra
authors.affiliation: Division of Cellular and Molecular Medicine, St George's Hospital Medical School, University of London, London SW17 0RE, UK.
authors.forename: Jason
authors.initials: J
authors.lastname: Hinds
authors.affiliation: Department of Infection, Immunity and Inflammation, University of Leicester, Leicester LE1 9HN, UK.
authors.forename: Peter W
authors.initials: PW
authors.lastname: Andrew
authors.affiliation: Department of Infection, Immunity and Inflammation, University of Leicester, Leicester LE1 9HN, UK.
authors.forename: Hasan
authors.initials: H
authors.lastname: Yesilkaya
mesh_terms: D000332:Aerobiosis; D000595:Amino Acid Sequence; D000693:Anaerobiosis; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D018441:Biofilms / Q000254:growth & development; D017931:DNA Primers / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D005260:Female; D020869:Gene Expression Profiling; D005798:Genes, Bacterial; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D018384:Oxidative Stress; D011008:Pneumococcal Infections / Q000382:microbiology; D018805:Sepsis / Q000382:microbiology; D017386:Sequence Homology, Amino Acid; D013296:Streptococcus pneumoniae / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D013482:Superoxide Dismutase / Q000235:genetics; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D017931:DNA Primers; D004269:DNA, Bacterial; D015534:Trans-Activators; C074779:rgg protein, Streptococcus; C095500:SodA protein, Bacteria; D013482:Superoxide Dismutase