CHEF gel and Southern hybridization analysis of transconjugants obtained from filter mating experiments employing primary transconjugant POTC-2 as the donor and JH2SS as the recipient. (A) I-ceuI-restricted DNA from three secondary transconjugants, POJTC-1, POJTC-2, and POJTC-3 (lanes 1, 2, and 3, respectively); donor POTC-2 (lane 4); and recipient JH2SS (lane 5). (B and C) Also shown are Southern hybridization analyses of I-ceuI-restricted DNA from the transconjugants (lanes 1 to 3), donor strain POTC-2 (lane 4), and recipient strain JH2SS (lane 5) using a 23S rRNA gene probe (B) and a Tn917-specific probe (C). Bacteriophage lambda concatemers were used as molecular size markers (lane M; New England Biolabs, Beverly, MA).