THE OXIDATIVE STRESS-RESPONSE IN ENTEROCOCCUS-FAECALIS - RELATIONSHIPBETWEEN H2O2 TOLERANCE AND H2O2 STRESS PROTEINS

The hydrogen peroxide (H2O2) stress response in Enterococcus faecalis ATCC19433 was investigated. A 2.4 mmol l(-1) H2O2 pretreatment conferr ed protection against a lethal concentration (45 mmol l(-1)) of this a gent. The relatively high concentrations of H2O2 used for adaptation a nd challenge treatments in Ent. faecalis emphasised the strong resista nce towards oxidative stress in this species. Various stresses (NaCl, heat, ethanol, acidity and alkalinity) induced weak or strong H2O2 cro ss-protection. This paper describes the involvement of protein synthes is in the active response to lethal dose of H2O2, in addition to the i mpressive enhancement of synthesis of five H2O2 stress proteins. Combi ned results suggest that these proteins might play an important role i n the H2O2 tolerance response.