Degradation of 16S RNA in Thermally Injured Staphylococcus Epidermidis

Abstract

Exposure of Staphylococcus epidermidis to sublethal temperatures produced a temporary change in the salt tolerance. After sublethal heat treatment at 52 °C for 20 min, 96% of the viable population was unable to reproduce on media containing 7.5% NaCl. The thermal injury results in alterations in the cell membrane allowing leakage of RNA into the heating media. Polyacrylamide gel electrophoresis revealed 16 S ribosomal RNA to be extensively degraded in thermally injured cells, whereas 23 S and 5 S RNA were unaffected. When the thermally injured cells were incubated at 37 °C in Trypticase Soy Broth, 16 S RNA was regenerated accompanied by a return of salt tolerance in the absence of DNA synthesis. In the presence of high concentrations of magnesium, cellular leakage of RNA was suppressed and the degradation of 16 S RNA was not observed in thermally injured cells.