Figure 1From: Construction of Bordetella pertussis strains with enhanced production of genetically-inactivated Pertussis Toxin and Pertactin by unmarked allelic exchangeVectors for the construction of a modified S1 gene into the allelic-exchange vector pSS4245. A: Allelic-exchange element for replacing the S1 gene by a chloramphenicol resistance cassette, inserted between the S1 flanging regions. B: Allelic-exchange element for returning the modified S1 gene into its exact location in the ptx-ptl operon. To obtain the allelic exchange, these vectors were linearized and inserted into pSS4245, which was then introduced into B. pertussis by conjugative transfer from E. coli SM10Back to article page