FIG. 5.
Effect of inactivation of QS pathways and of indole on Stx2 synthesis. (A) Stx2 concentrations were measured in EDL933 qseA, qseC, and sdiA isogenic mutants after 6 h and 24 h of growth in nonconditioned medium and medium conditioned with human fecal microbiota. (B) stx2 mRNA levels were measured in EDL933 after 3 h and 6 h of growth in Dulbecco's modified Eagle's medium without or with 1 mM indole. Data represent the mean ± SEM of at least three independent experiments performed in duplicate. *, P < 0.05.