Fig. 4

The identified active metabolites mediate increased pathogenicity. a–c Effect of 3,4-dimethylbenzoic acid, 4-methylbenzoic acid, hexanoic acid, and heptanoic acid (4 metab.) on epithelial injury in the Colon Chip in the presence or absence of EHEC, with or without Mmm, compared to the effects of Hmm with EHEC. a Representative DIC images of the colon epithelium under the various experimental conditions (bar, 100 μm). b Pseudocolored view of the entire epithelial layer in the Colon Chip (yellow) under the same conditions. c Quantification of epithelial lesion area size under conditions shown in b. Epithelial lesion defined as regions in which cells normally contained within a continuous intact epithelium have fully detached from the ECM-coated membrane and their neighboring cells, thus, leaving exposed regions of the membrane below. *p < 0.05; **p < 0.01