Southern hybridization. The A. fermentans 8.3-kb EcoRI DNA fragment was labeled and used as a probe for Southern blot analysis. Lane 1, RYC4093 genomic DNA digested with BamHI; lane 2, RYC4093 genomic DNA digested with EcoRI; lane 3, RYC-MR95 genomic DNA digested with BamHI; lane 4, RYC-MR95 genomic DNA digested with EcoRI; lanes 5 and 6, same as lanes 3 and 4, respectively, with slightly higher concentrations of DNA; lane 7, plasmid pJC1 digested with EcoRI. Molecular sizes are shown, in kilobases.