Figure 1

PCR verification of allelic disruptions in H. pylori strain G27. Genomic DNA was prepared from gene-disrupted G27 strains following three passages under chloramphenicol selection, then PCR amplified as shown in each scheme. Primers sequences are given in Table 1. A. Disruption of cgt. Five examples are shown out of seven individual clones, all of which gave identical results in the screen. B. Disruption of pmi (rfbM). The entire chloramphenicol-resistant population was passaged in each round of selection, without clonal selection. C. Disruption of lpxE and eptA. The entire chloramphenicol-resistant population was passaged in each round of selection, without clonal selection.