title: Defenses against oxidative stress in Neisseria gonorrhoeae and Neisseria meningitidis: distinctive systems for different lifestyles.
abstract: Defenses against oxidative stress are crucial for the survival of the pathogens Neisseria meningitidis and Neisseria gonorrhoeae. An Mn(II) uptake system is involved in manganese (Mn)-dependent resistance to superoxide radicals in N. gonorrhoeae. Here, we show that accumulation of Mn also confers resistance to hydrogen peroxide killing via a catalase-independent mechanism. An mntC mutant of N. meningitidis is susceptible to oxidative killing, but supplementation of growth media with Mn does not enhance the organism's resistance to oxidative killing. N. meningitidis is able to grow in the presence of millimolar levels of Mn ion, in contrast to N. gonorrhoeae, whose growth is retarded at Mn concentrations >100 micromol/L, indicating that Mn homeostasis in the 2 species is probably quite different. N. meningitidis superoxide dismutase B plays a role in protection against oxidative killing. However, a sodC mutant of N. meningitidis is no more sensitive to oxidative killing than is the wild type. A cytochrome c peroxidase (Ccp) is present in N. gonorrhoeae but not in N. meningitidis. Investigations of a ccp mutant revealed a role for Ccp in protection against hydrogen peroxide killing. These differences in oxidative defenses in the pathogenic Neisseria are most likely a result of their localization in different ecological niches.
authors.affiliation: Department of Microbiology and Parasitology and Centre for Metals in Biology, School of Molecular and Microbial Sciences, University of Queensland, Brisbane, Australia.
authors.forename: Kate L
authors.initials: KL
authors.lastname: Seib
authors.forename: Hsing-Ju
authors.initials: HJ
authors.lastname: Tseng
authors.forename: Alastair G
authors.initials: AG
authors.lastname: McEwan
authors.forename: Michael A
authors.initials: MA
authors.lastname: Apicella
authors.forename: Michael P
authors.initials: MP
authors.lastname: Jennings
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D003470:Culture Media; D018869:Heat-Shock Response; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008345:Manganese / Q000494:pharmacology*; D009344:Neisseria gonorrhoeae / Q000187:drug effects / Q000254:growth & development* / Q000502:physiology; D009345:Neisseria meningitidis / Q000187:drug effects / Q000254:growth & development* / Q000502:physiology; D018384:Oxidative Stress; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D008345:Manganese; D006861:Hydrogen Peroxide; D002374:Catalase; D013482:Superoxide Dismutase