Fig. 3
Analysis of Sat expression during EcN colonization of mouse intestine. a In vivo expression of the promoter fusion sat-gfp mut3.1 in samples derived from the intestine of mice colonized with EcN harbouring pFU34-sat, or pFU34 as a control. Doses of 2x105 bacteria of the indicated strains were used to inoculate orogastrically CD-1 mice (eight- to ten-weeks old), which were provided with drinking water containing ampicillin from 48 hours prior to inoculation and over the entire course of the experiment. Five days post-inoculation fresh stool samples, as well as the mucus layer from the ileon and colon sections, were collected. A drop of each fecal or mucosal suspension was deposited on a slide and visualized by fluorescence microscopy. Representative images derived from one mouse of each type are shown. b Western blot analysis of EcN Sat adhered to intestinal mucus of colonized mice. Ileon and colon mucus collected from inoculated mice were homogenized and proteins precipitated with TCA. Equivalent samples collected from non-inoculated mice were processed in parallel for control. Cell-free supernatants (SN) from EcN cultures grown in LB were used as a positive immunoblotting control