Fig. 5. : effect of water-exposure on Helicobacter pylori cag type IV secretion system formation. A: AGS cells were infected with H. pylori 26695 inocula that have been exposed to water for 2 h, 6 h, 24 h and 48 h at a multiplicity of infection of 100. As control, H. pylori 26695 that were not exposed to water were used (Hp). cagA tyrosine phosphorylation levels were evaluated by western blot using an anti-PY99 antibody against tyrosine phosphorylated motifs and after membrane stripping, cagA was detected by re-probing with an anti-cagA antibody. Tubulin was used as equal protein loading control for co-cultures; B: protein lysates of H. pylori 26695 suspensions of each timepoint of water exposure were used as parallel controls of the amount of bacterial cagA and urease B proteins present. H. pylori 26695 that were not exposed to water (Hp) were also used as control.