(A) Schematic of protocol for gnotobiotic mouse experiments, tissue collection and processing, image acquisition, and analysis.
(B,C) Segments of mouse distal colon fixed in (B) 4% paraformaldehyde or (C) methacarn solution. Blue, DAPI staining in the epithelium; red, DAPI staining in lumen of gut, including bacteria and shed host nuclei (luminal debris has not been differentiated in this image); green, antibody staining for MUC2. Scale bars: 10 µm.