FIG. 1.

Schematic of generation of Salmonella enterica serovar Typhimurium SL3261 strains carrying a foreign epitope in fimbrin. Salmonella enterica serovar Typhimurium SL3261 genome DNA was used as the target for amplification of the chimeric agfA genes by two-step overlap PCR. The chimeric genes were constructed in pHSG415, which is an unstable and temperature-sensitive plasmid, to generate pHSG-ESO9 and pHSG-ESO11. The recombinant plasmids were then transferred into SL3261. Finally, we obtained mutant strains through gene replacement by the use of temperature control and biotic pressure, as described in the text.