FIG 3 .
Chitin is sufficient to induce TfoS activity at the tfoR promoter in the heterologous host Escherichia coli. (A) Miller assays for E. coli PtfoR-lacZ fusion strains containing either pGST-′TfoS or pGST (empty vector) grown in M9 plus glucose. (B) Miller assays for the E. coli PtfoR-lacZ fusion strain containing pTfoS grown in M9 plus the indicated carbon source (at 3.33 mM for trisaccharides, 5 mM for disaccharides, and 10 mM for monosaccharides) in the presence of 10 µM IPTG. (C) Miller assays for the E. coli PtfoR-lacZ fusion strain grown under the same conditions outlined in panel B. All data are from at least three biological replicates and are shown as means ± SD. Statistical comparisons were made by Student’s t test. ***, P < 0.001; NS, not significant.