Figure 2. Visualization of the bacterial inoculum in the gastrointestinal tract via light emission.
Low gastric pH was induced in mice by histamine injection prior to inoculation with 1×109 CFU of S. Typhi Ty2(pGEN-luxCDABE). At 30, 60 and 90 min post-inoculation, the gastrointestinal tract was removed and examined for the production of light by luciferase. A visible signal is equivalent to approximately 5×105 CFU. Luminescence is reported as the number of photons detected per s per square cm. Images shown are representative results from groups of seven mice.