Fig. 2.

The FDAA probes used in this study and their labeling of gut microbiota in vivo. a Structures of TADA, TADA-amide, and TADA-ester. b Confocal fluorescence images of gut microbes from mice administered with TADA-amide. DIC, differential interference contrast. Scale bar, 10 μm. c Statistical analysis of the labeling coverage for gut microbes labeled with TADA, TADA-amide, and TADA-ester. Mean ± s.d. are presented for n = 3. d Flow cytometry analysis of TADA-amide-labeled gut microbiota with different labeling time. NC negative control; 1 × 4 h, one gavage and microbiotas collected 4 h later; 2 × 3 h, two gavages with a 3 h interval, and microbiotas collected 3 h after the second gavage. e Confocal fluorescence imaging of the transplanted gut microbiota (green) on the tissue sections of the recipient mouse’s large intestine (L.I.) and small intestine (S.I.). Hoechst 33342 (blue) was used for nuclear counterstain. In b, e, representative results from three independent experiments are shown. Scale bar, 50 μm