Clostridium perfringens, a strictly anaerobic bacterium, is able to survive when exposed to oxygen for short periods of time and exhibits a complex adaptive response to reactive oxygen species, both under aerobic and anaerobic conditions. However, this adaptive response is not completely understood. C. perfringens possesses specialized genes that might be involved in this adaptive process, such...

The marine foodborne enteropathogen Vibrio parahaemolyticus has four putative catalase genes. The functions of two katE-homologous genes, katE1 (VPA1418) and katE2 (VPA0305), in the growth of this bacterium were examined using gene deletion mutants with or without complementary genes. The growth of the mutant strains in static or shaken cultures in a rich medium at 37°C or at low temperatures (...

The resistance of Mycobacterium tuberculosis to isoniazid is commonly linked to inactivation of a catalase-peroxidase, KatG, that converts isoniazid to its biologically active form. Loss of KatG is associated with elevated expression of the alkylhydroperoxidases AhpC and AhpD. AhpD has no sequence identity with AhpC or other proteins but has alkylhydroperoxidase activity and possibly additional...

Nine structural genes (furA, katG, inhA, kasA, Rv0340, iniB, iniA, iniC, and efpA) and two regulatory regions (the oxyR-ahpC intergenic region and the promoter of mabA-inhA) in 87 isoniazid (INH)-monoresistant and 50 INH-susceptible Mycobacterium tuberculosis isolates collected from five provinces of China were analyzed by sequencing. Eighty-two (94.3%) INH-resistant isolates had mutations in t...

Heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) is associated with clinical treatment failure. However, the resistance mechanism of hVISA has not been fully clarified. In the present study, comparative proteomics analysis of two pairs of isogenic vancomycin-susceptible S. aureus (VSSA) and hVISA strains isolated from two patients identified five differentially expressed prot...

A Campylobacter jejuni gene encoding a homologue of the flagellar biosynthesis gene flhB was identified downstream of the peroxide stress defence gene ahpC. Insertional mutagenesis of the flhB gene rendered C. jejuni non-motile, with most cells aflagellate, although a small number expressed truncated flagella. The absence of FlhB also appeared to affect cell shape, as the majority of cells were...

Peroxiredoxins (Prxs) are a widespread and highly expressed family of cysteine-based peroxidases that react very rapidly with H₂O₂, organic peroxides, and peroxynitrite. Correct subfamily classification has been problematic because Prx subfamilies are frequently not correlated with phylogenetic distribution and diverge in their preferred reductant, oligomerization state, and tendency toward ove...

The ohr (organic hydroperoxide resistance) gene product of Pseudomonas aeruginosa was essential for optimal resistance to organic hydroperoxides (OHPs) but not to hydrogen peroxide or paraquat. A Deltaohr mutant was hypersusceptible to OHPs in disk inhibition assays and showed enhanced killing by OHPs in liquid culture. The ohr gene product was demonstrated to contribute to the decomposition of...

A computational search was carried out to identify additional targets for the Escherichia coli OxyR transcription factor. This approach predicted OxyR binding sites upstream of dsbG, encoding a periplasmic disulfide bond chaperone-isomerase; upstream of fhuF, encoding a protein required for iron uptake; and within yfdI. DNase I footprinting assays confirmed that oxidized OxyR bound to the predi...