FIG 2.

Scanning electron microscopy of S. flexneri 2457T adherence on the human intestinal organoid-derived epithelial monolayer model. S. flexneri 2457T was subcultured in IVLCs, washed, and applied for adherence analysis on the HIODEM model. Following infection, samples were fixed and processed for SEM analysis. The images on the top row display the association of bacteria with the cells of the model. The middle and bottom rows are images from a higher magnification. Magnifications, approximately ×7,000 (top row) and approximately ×20,000 (bottom row). Pseudocoloring was performed to enhance the visualization of the three types of putative adherence factors visualized on the bacteria that interact with the apical surface of the epithelial cells. The bacterial rods are colored teal, thicker structures are colored green, thinner structures are colored yellow, and electron-dense aggregates are colored blue. The images in the left and right columns represent those from two separate biological samples.