FIG. 5.

Viable counts of L. johnsonii cells along the mouse gastrointestinal tract. (A) Numbers of live bacteria expressed as log₁₀ numbers of CFU/g (wet weight) in the lumina (squares) or associated with the mucosae (circles) of antibiotic-treated conventional mice 48 h after the last forced-feeding with strain NCC533 (containing an antibiotic resistance plasmid) in the specified gut segments. The filled symbols give the median value for each group of five mice, and the open symbols give the individual values. If fewer than five symbols are seen, they are overlaid by the median. (B) Schematic representation of the murine gastrointestinal tract. 1, forestomach lumen; 2, forestomach (the corpus mucosa of which was scraped); 3-4, lumen and mucosa of duodenum; 5-8, proximal lumen, mucosa, distal lumen, and mucosa of jejunum; 9-14, ileum (which was sectioned into the proximal ileum, middle and distal parts, first lumen, and mucosa); 15, cecum (only the lumen is represented, since there is no cecal mucosa that can be scraped off); 16-21, colon (which was sectioned into a proximal and a distal part, and then from each half, the lumen was squeezed out [fractions 16 and 19], the tube was washed [fractions 17 and 20], bacteria were not counted, and the mucosa was scraped off [fractions 18 and 21] [there are thus four colon samples]).