title: Fumarate reductase is a major contributor to the generation of reactive oxygen species in the anaerobe Bacteroides fragilis.
abstract: Despite the detrimental role that endogenously generated reactive oxygen species (ROS) may play in bacteria exposed to aerobic environments, very few sources of ROS have been identified in vivo. Such studies are often precluded by the presence of efficient ROS-scavenging pathways, like those found in the aerotolerant anaerobe Bacteroides fragilis. Here we demonstrate that deletion of the genes encoding catalase (Kat), alkylhydroperoxide reductase (AhpC) and thioredoxin-dependent peroxidase (Tpx) strongly inhibits H(2)O(2) detoxification in B. fragilis, thereby allowing for the quantification of ROS production. Exogenous fumarate significantly reduced H(2)O(2) production in a ΔahpCΔkatΔtpx B. fragilis strain, as did deletion of fumarate reductase subunit c (frdC). Deletion of frdC also increased the aerotolerance of a strain lacking superoxide dismutase, indicating that fumarate reductase is a major contributor to ROS formation in B. fragilis exposed to oxygen.
authors.affiliation: Department of Molecular Biology and Microbiology, Tufts University Sackler School of Graduate Biomedical Sciences, Boston, MA 02111, USA.
authors.forename: Brian M
authors.initials: BM
authors.lastname: Meehan
authors.affiliation: Department of Molecular Biology and Microbiology, Tufts University Sackler School of Graduate Biomedical Sciences, Boston, MA 02111, USA.
authors.forename: Michael H
authors.initials: MH
authors.lastname: Malamy
mesh_terms: D000693:Anaerobiosis; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001441:Bacteroides fragilis / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism*; D013385:Succinate Dehydrogenase / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D006861:Hydrogen Peroxide; D013385:Succinate Dehydrogenase
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