Mycoplasma-infected cell cultures. Hoechst 33258 fluorochrome staining [M. Battaglia, D. Pozzi, S. Grimaldi, T. Parasassi. 1994 - Hoechst 33258 staining for detecting mycoplasma contamination in cell cultures: a method for reducing fluorescence photobleaching. Biotechnic & Histochemistry 69:152-156].