FIG. 3.

Screen for inhibitors of type III secretion by EPEC with no change in bacterial viability. (A) Graph of ELISA results monitoring percent EspB secretion compared to that in untreated EPEC. Bacteria were treated with the compounds at 40 μM for 3 h. The right panel graphs the viability of EPEC as measured by OD₆₀₀. The results are shown ± standard deviation and are the average of three different experiments performed in triplicate. (B) Western blot for secreted proteins Tir and EspB in wt EPEC, ΔescN (type III apparatus mutant that does not secrete Tir or EspB), and wt EPEC treated with the compounds as described above. (C) Total secreted protein stained by Sypro-Ruby (Bio-Rad).