Regulation of Brucella abortus catalase as a defensive mechanism against oxidative stress

In this study, we investigate the expression of Brucella abortus proteins in resporise to oxidative stress. The focus is on several proteins thought to be involved in bacterial protection. We show that catalase and Cu-Zn superoxide dismutase are regulated in response to H2O2 or by superoxide, whereas expression of Hsp70 and Hsp60 are not dramatically affected by oxidative stress. The regulation and protective function of periplasmic catalase is studied in more detail. The results demonstrate that periplasmic catalase in B. abortus is regulated at the transcriptional level in response to external hydrogen peroxide, and a catalase deletion mutant is more susceptible than wild type to external H2O2. 1 Primary researcher and author 2 Graduate student who made catalase deletion mutant and did the hydrogen peroxide sensitivity experiments (Fig. 2) ^ Major Professor