FIG. 3.

PCR confirmation of the deletion of 15.6-kb rtxA1 and creation of ΔrtxA1::aph. Genomic DNAs from V. vulnificus CMCP6 (lane A) and ΔrtxA1::aph strain FLA900 (lane B) were PCR amplified using oligonucleotide primers rtxA1-deletion-up and rtxA1-deletion-down, which amplify 1 kb upstream and downstream of the start and stop codons of rtxA1. The sizes of the products are shown to the left, based on the 1-kb ladder (lane C) and lambda phage-HindIII digestion (lane D). Southern blot analysis also confirmed the absence of rtxA1 sequences (data not shown).