Fig. (1) Deletion of the vicK gene. A) schematic for vicK deletion by gene replacement. The two flanking fragments of the internal vicK fragment to be deleted were cloned into the up- and down-stream ends of the aad gene in pGRV. The resulting plasmid pGRV-ΔvicK was introduced into S. equi, and double crossover in the homologous regions between the plasmid and S. equi genome resulted in ΔvicK mutants. B) PCR confirmation of the vicK dele-tion. The picture shows agarose gel analysis of PCR reactions using mutant (lane ΔvicK) or wild-type (lane wt) genomic DNA as tem-plate and primers indicated by the arrows under the mutant genome