Radiosensitization of bacterial spores by potassium permanganate

SummaryPotassium permanganate sensitizes spores of Bacillus megaterium in anoxic phosphate buffer (pH 7·0) or water suspension to the lethal effects of gamma-rays. At sufficiently high concentrations, it increases the radiation sensitivity to a level equivalent to that seen for spores in suspension in equilibrium with oxygen, but does not enhance the sensitivity of spores oxygenated fully. Under conditions where responses due to oxygen presence are sub-maximal, potassium permanganate increases radiation sensitivity, but only to a level achieved maximally by oxygen alone; oxygen and potassium permanganate sensitizing effects are thus additive within the oxygen effect. The proposal is made that potassium permanganate acts, in part, in wet spores by oxidation of those radiation-induced free radicals, produced directly in target molecules within spores, that can also be made harmful by interaction with oxygen.