We stained these samples for MUC2 using a rabbit polyclonal anti-MUC2 IgG antisera originally developed against the colon carcinoma line LS174T (41), as well as the bacterial microbiota using a universal bacterial-specific probe (EUB338) for fluorescence in situ hybridization (FISH) (42), and visualized the mucus structure and microbiota by fluorescence microscopy (Fig. 1B). Here, MUC2 is linked to colon carcinoma.