Figure 6

EPS2 is more important for the adhesion of B. cereus cells to human epithelial cells and to the zebrafish gut. (A) Adhesion assays in cultures of the human HeLa and MDA epithelial cell lines. Means compared using t-student (P < 0.05). (B) Top left, representative image of a zebrafish larva 6 days post-fertilization (dpf). Bottom left graph, rates (±SD) of 6-dpf zebrafish larvae harboring fluorescent bacteria in the GI tract 24 h after feeding with the WT, Δeps1, Δeps2 or double-mutant B. cereus strains (1 E8 ucf/ml). Means compared using t-student (P < 0.05). Right panel, bacterial localization in the gut of the zebrafish larvae after infection. The bacterial strains were transformed with a plasmid expressing the yfp gene under the control of a constitutive promoter. a-d´: Fluorescent Z-stack confocal microscopy images (the bacteria marked with asterisks in a-d are magnified in a´-d´). Scale bars = 200 μm in a,b,c,d, 100 μm in a-d, and 1 μm in a´-d´.