Induction of superoxide dismutase in Escherichia coli by heat shock.

Exposure of midlogarithmic-phase cultures of Escherichia coli B to 48 degrees C for 1 hr elicited an induction of the manganese-containing superoxide dismutase (MnSOD), which became more pronounced during 1 hr of recovery at 37 degrees C. This induction required protein biosynthesis, since it was suppressed by chloramphenicol. Induction of MnSOD appeared to be a response to a heat-mediated increase in O2- production because it was dioxygen-dependent and because heating to 48 degrees C doubled the cyanide-resistant fraction of the total respiration.