Figure 2. Intracellular ppGpp levels in the C. jejuni ∆ppx mutants. The amount of ppGpp accumulation was assessed in MOPS using early log phase culture labeled with ³²P. The nucleotides were resolved by TLC and quantified using densitometry. The graph shows the percentage decrease/increase in the levels of ppGpp in mutants at 24 h. The complemented strains (Cppx1 and Cppx2) did not show a significant change in the intracellular ppGpp pool compared with wild type as chloramphenicol has been shown to inhibit ppGpp synthesis (data not shown). Each bar represents the average from 2 independent experiments performed using duplicate samples in each experiment.