FIG. 2.

(A) Southern transfer and hybridization of EcoRI chromosomal DNA digests from different Bacillus strains with a ³²P-labeled 0.53-kb DNA fragment containing rtp as the probe. Lanes: 1, DNA from B. subtilis W23; 2, B. amyloliquefaciens; 3, B. atrophaeus; 4, B. mojavensis; 5, B. vallismortis; 6, B. subtilis 168. Sizes of the hybridizing fragments are in kilobases. (B) Schematic representation of the relative positions of TerI and TerII to rtp in the chromosome of B. subtilis. A clockwise fork would pass through rtp and TerII and be arrested by TerI, while TerII has the potential to arrest a fork approaching from the counterclockwise direction.