FIG. 5.

Amount of Stx in total cultures of the 933W lysogens K10599, containing a prophage encoding the wild-type repressor (WT), and K10595, containing a prophage encoding the noncleavable form of repressor (Ind⁻), as determined by ELISA using Stx antisera. Stx production was quantified from whole-cell sonicated lysates and culture supernatants obtained from cultures grown in the presence (A) and absence (B) of the prophage inducing agent mitomycin C. Stx production was quantified from cultures grown in the presence of mitomycin C at 1.5 and 3 h following the addition of the inducing agent. The total protein concentrations analyzed for Stx were 0.5 μg/ml (A) and 40 μg/ml (B). Samples were analyzed in triplicate, and the results are representative of four independent experiments. ND*, not detectable.