FIG. 6.

Flow diagram showing construction of various recombinant plasmids for the purpose of generating the fur isogenic mutant of A. hydrophila SSU. Plasmid pBfur contained a 2.6-kb DNA fragment from the chromosome of A. hydrophila, which included the fur gene. The fur locus was truncated at the BglII restriction site by introducing a kanamycin resistance cassette from plasmid pUC4K. The truncated fur locus with its flanking sequences was cloned into a suicide vector, pDMS197, forming a recombinant plasmid, pDMS197fur, for the generation of a fur isogenic mutant of A. hydrophila. The shaded bars represent the fur gene, the dotted bars represent sequences flanking the fur gene, and the open bars indicate the kanamycin cassette. These plasmids are not drawn to scale.