Fig 1.
Ohr and OhrR are important determinants of resistance to organic hydroperoxide stress in Brucella abortus 2308. Isogenic ohr and ohrR mutants were constructed in Brucella abortus 2308, and each mutant strain was complemented with a plasmid-borne copy of the corresponding gene. These strains were tested in a disk diffusion assay for their comparative susceptibilities to hydrogen peroxide (H2O2) and the organic peroxide cumene hydroperoxide. The results are plotted as the average diameter (± standard deviation) of the zone of inhibition around a disk containing the indicated peroxide, and the results are from single experiment that was repeated in triplicate. An asterisk denotes a statistically significant difference (P < 0.05) between a given strain and the parental strain 2308.