Figure 2.

(a) Southern blotting of DNA from wild‐type B11 and mutant strains after digestion with restriction enzymes. The DNA extracted from wild‐type B11 and the mutant strains was digested with PstI. The restricted DNAs were electrophoresed, transferred to nitrocellulose, and hybridized to mixed DIG‐High Prime. The single band indicated that only a single mini‐Tn10 transposon was inserted in the mutants. (b) The number of surviving mutant bacteria in 1 ml of cells was analyzed 1 hr after invasion of the macrophages. Wild‐type B11 was the control. Values denoted by different numbers of asterisks were significantly different when compared by ANOVA (“**” p < .01; “*” p < .05)