COMPARISON OF THE BILE-SALTS AND SODIUM DODECYL-SULFATE STRESS RESPONSES IN ENTEROCOCCUS-FAECALIS

The resistance to detergents and detergent-induced tolerance of a gast rointestinal organism, Enterococcus faecalis ATCC 19433, were examined , The most remarkable observation was the rapid response of cells in c ontact with bile salts and sodium dodecyl sulfate (SDS), The killing b y high concentrations of detergents was nearly instantaneous, A 5-s ad aptation with moderate sublethal concentrations of bile salts or SDS ( 0.08 or 0.01%, respectively) was sufficient to induce significant adap tation against homologous lethal conditions (0.3% bile salts or 0.017% SDS), However, resistance to a subsequent lethal challenge progressiv ely increased further to a maximum reached after 30 min of adaptation, Furthermore, extremely strong cross-resistances were observed with bi le salts- and SDS-adapted cells, However, no relationship seems to exi st between levels of tolerance and de novo synthesized proteins, since blockage of protein synthesis during adaptation had no effect on indu ction of resistance to bile salts and SDS, We conclude that this induc ed tolerance to detergent stress is independent of protein synthesis, Nevertheless, the stress-induced protein patterns of E. faecalis ATCC 19433 showed significant modifications. The rates of synthesis of 45 a nd 34 proteins were enhanced after treatments with bile salts and SDS, respectively, In spite of the overlap of 12 polypeptides, the protein profiles induced by the two detergents were different, suggesting tha t these detergents trigger different responses in E. faecalis, Therefo re, bile salts cannot be substituted for SDS in biochemical detergent shock experiments with bacteria.