FIG. 1.

(A) A putative Porphyromonas DNA transfer region. The genome region from P. gingivalis strain W83 that is similar to the Bacteroides DNA transfer genes from conjugative transposons is shown. PCR regions used as probes for Southern blots are indicated by thick horizontal bars. (B) Southern blots of P. gingivalis strains for tra genes. Results are shown for strains W83 (lanes 1), W50 (lanes 2), ATCC 49417 (lanes 3), 5083 (lanes 4), ATCC 33277 (lanes 5), 381 (lanes 6), A1A7-28 (lanes 7), and MP4-504 (lanes 8). Band sizes for strain W83 are indicated to the left of the blots.