FIG. 4.

The joined ends of the excised circular form of CTnBST were PCR amplified from each of the listed strains carrying each of the listed plasmids shown in Fig. 3 and described in Table 1. BT4020, a strain that carries a wild-type copy of CTnBST, was used as a positive control. BT4001 does not contain CTnBST and was used as a negative control in this experiment. As a positive control for the amplification reaction the gene that encodes sigma 70 in Bacteroides was successfully amplified from each strain but is not shown here.