Figure 2: Bromo- and nitrothiazolides induce the expression of a spy::lacZ fusion. The wild type (M5402) and tolC mutant (M5403) strains were grown for 2.5 h in the presence of various thiazolides, nalidixic acid (Nal; all 1 μM) or DMSO as a solvent control. Beta-galactosidase activity was determined as described [18] and expressed as relative values to the corresponding solvent controls of each strain. Mean values (± SE) are given in triplicates. Values marked by asterisks are significantly different between the treatments and the solvent control (paired t-test, two-sided; *, P<0.01).