FIG. 3.

RTX toxin is active when bacteria are added to either the apical or basolateral chamber. PBS-washed Bah1P (10 μl) was added to the apical chamber or Bah1P (50 μl) was added to the basolateral chamber. Both additions correspond to a 1:20 dilution in the total volume of the chamber. Values were derived by dividing the recorded resistance (R) value by the mean of three initial resistance values recorded before addition of bacteria and are means and standard deviations of triplicates in a single experiment.