FIG. 1.
Physical map of the Bordetella tonB exbB exbD chromosomal region and relevant constructions described in this study. The recombinant plasmid-associated Lac phenotypes in the Fur titration assay are indicated on the right. Blocks representing ORFs are drawn to scale; arrowheads indicate the direction of transcription. Certain restriction sites are indicated as follows: BclI (BcI), ClaI (C), EcoRI (RI), HincII (H), KpnI (K), NruI (N), PstI (P), SalI (S), and XhoI (X). (A) The B. pertussis tonB exbB exbD locus cloned as a 3.1-kb EcoRI fragment in pCG475. (B) Inserts in Bordetella suicide plasmids pEP491, pEP549, and pEP552. pEP552 was used for allelic exchange to construct the B. pertussis ΔtonB exbB::ΩKmR mutant BPEP98. (C) The B. bronchiseptica tonB upstream region subcloned as a 2.4-kb EcoRI fragment in pEP532. Derivatives tested in the Fur titration assay are indicated.