Fig. 1.
(a) Comparison of the survival of the dltD mutant (grey) and the Lactobacillus rhamnosus GG (LGG) wild-type strain (black) in simulated gastric juice at pH 2 and pH 4. The dotted line indicates that the viable cell count at start was taken as 100%. Data are the means of triplicate experiments, and error bars indicate standard error of the mean. (b) Comparison of the persistence of the dltD mutant with the wild-type control. A 1 : 1 mixture of wild-type control strain and the dltD mutant (ca. 109 colony-forming unit (CFU)/mice) was administered to three mice, indicated by the horizontal line. The percentage of mutants in the whole LGG population was determined in the fecal samples, taken at different time-points. Values for individual mice are shown. (c) Persistence of LGG wild-type and dltD mutant in 3% moderate to severe dextran sulphate sodium (DSS)-induced colitic mice. Ca. 5 × 108 CFU of each strain were administered daily to five mice. Black diamonds represent individual mice and the grey bars represent the mean value.