Additive Sensitization of Bacterial Spores by Oxygen and p-Nitroacetophenone

In the bacterial spore, the sensitizing effects of both oxygen and p-nitroacetophenone (PNAP) can be separated into components. Each sensitizer has a component of damage which involves reactions of hydroxyl radicals (·OH), although the origins of these components may be different. Tests which use different concentrations of PNAP and O2 simultaneously have been run to seek interactions or additivities in their effects on lethal radiation sensitivity. The results show that the effects of the PNAP non-·OH component are additive to those of both O2 non-·OH components; however, the patterns of this additivity suggest that the chemical processes through which PNAP acts are similar to those of the high- O₂ component (that is, the component which occurs at [ O₂]>5× 10⁻⁵ M) but are different from those of the low- O₂ component. There is also indirect evidence that the sensitizing reactions of the high- O₂ component may replace those reaction...