Characterization of a peroxide-resistant mutant of the anaerobic Bacterium bacteroides fragilis.

ABSTRACT: A Bacteroides fragilis mutant resistant to hydrogen peroxide and alkyl peroxide was isolated by enrichment in increasing concentrations of hydrogen peroxide. The mutant strain was constitutively resistant to 100 mM H2O2 and 5 mM cumene hydroperoxide (15-min exposure). In contrast, the parent strain was protected against <10 mM H2O2 when the peroxide response was induced with a sublethal concentration of H2O2, and no protection was observed in untreated cells. In addition, catalase activity in the mutant strain was not repressed in anaerobic cultures as reported previously for the parent strain. Comparison of the protein profile of crude extracts of the B. fragilis strains revealed that at least three oxidative stress-induced proteins in the parent strain were constitutively expressed in th

SUBMITTER: Rocha ER 

PROVIDER: S-EPMC107664 | biostudies-literature | 1998 Nov

REPOSITORIES: biostudies-literature