FIG. 4.

Determination of the size and conformation of the genomic elements that carry ORF 1- and ORF 4-related sequences. DNA was fractionated by 2D CHEF-PFGE as described in the text. The direction of electrophoresis in each dimension is indicated. Arrowheads indicate the locations of the linear plasmids. The gel shown in panel A was blotted and probed with an ORF 1 probe (B), while a similar gel was used in the ORF 4 analyses (C). Isolates analyzed were B. garinii FRG (lane 1), B. valaisiana VS116 (lane 2), and B. afzelii IP21 (lane 3). The migration positions of the approximately 980-kb linear chromosome (lc) (7), 50-kb ospAB-carrying LP (lp50) (8), 80-kb LP of isolate VS116 (lp80) (27), and cp8.3 are indicated. The migration positions of the CPs are not indicated but can be seen just to the left of the LPs of isolate FRG in panel A. It is important to note that lp80, the size of which was determined in a previous study, is carried only by VS116 (27). The signal to the right of the FRG LPs in panel C represents background.