An investigation into the mutagenic after-effect of butadiene diepoxide usingNeurospora crassa

Summary Butadiene diepoxide (DEB) was used to induce reverse mutations in anad-3A mutant ofNeurospora crassa. It was found that the mutagenic action of DEB continued when the twice washed and resuspended conidia were left standing in water at room temperature. The after-effect can be prevented if the conidia are kept stirred by shaking or gaseous bubbling for 4–5 hours. The after-effect does not develop if the conidia are plated immediately after washing, or if they are kept at 0–4°C until plating. The experimental data indicate that the after-effect is caused by traces of DEB, or by mutagenic reaction products of DEB, which are not readily removed by the ordinary washing procedure, but which may be removed by diffusion from the cells when these are kept suspended for a prolonged period.With 3 Figures in the Text