Abstract
The yield of inactivation of radioresistant strains of Escherichia coli K-12 (wild type and uvr A mutant) suspended in phosphate-buffered saline (PBS) is higher in suspensions irradiated under N2O-bubbling than in suspensions irradiated under N2-bubbling. This sensitization is largely a result of OH-induced toxic products formed in N2O-saturated PBS. Special emphasis is placed on establishing the conditions under which extracellular toxic products with lifetimes exceeding about 20 s are formed. Cl atoms are apparently precursors for these toxic products and N2O and phosphate may potentiate their formation.