Breaking survival curves and oxygen removal times in irradiated bacterial spores.

Although there are ambiguities about these results and their interpretations, this unambiguous experimental observation was made: the two kinds of experiments designed to measure deoxygenation times did not give the same answer, for a given N2 flushing rate, unless t-butanol was present. The addition of t-butanol caused large changes in the positions of the survival curve breakpoints, but only small changes in the 'times to anoxia' in the pre-irradiation glushing experiments. Although careful additional work is needed, these initial results suggest that in the spore, the survival curve breakpoint probably does not represent the dose at which anoxia is reached unless t-butanol is present.