Viability of Escherichia coli treated with colicin K.

Conditions permitting survival (colony formation) of E. coli after treatment with colicin K have been found. Survival required K+ and Mg2+ at concentrations high enough to replace the intracellular ions lost from colicintreated cells. Either glucose minimal medium or broth could support survival. Survival was still observed after colicin-promoted efflux of Rb+ and decline in ATP levels had occurred, and after the period during which treatment with trypsin could rescue the cells on media containing low concentrations of K+. In an adenosinetriphosphate (ATP phohsphohydrolase, EC 3.6.1.3) deficient (uncA) mutant, survival after colicin treatment was observed at lower Mg2+ concentrations than those required by the wild type, and Rb+ could replace K+. Cells treated with colicin E1 (but not with colicin I2, E3, or Ib) also survived under conditions permitting survival of colicin K.