Distribution of rpoB duplication among Nocardia strains. Total DNAs extracted from N. asteroides IFM 0319T (lane 1), N. asteroides IFM 10159 (lane 2), N. asteroides IFM 10162 (lane 3), N. brasiliensis IFM 0236T (lane 4), N. brasiliensis IFM 0406 (lane 5), N. brasiliensis IFM 10132 (lane 6), N. brasiliensis IFM 10160 (lane 7), N. farcinica IFM 0284T (lane 8), N. farcinica IFM 10125 (lane 9), and N. farcinica IFM 10152 (lane 10) were digested with BamHI and probed with a 437-bp fragment containing the C-terminal region of rpoB. The probe was prepared from the total DNA of N. farcinica IFM 10152 by PCR using the primers NFrpoBF and NFrpoBR.