Fig. 4.

Bifidobacterium sp. CS stimulates DRA promoter activity in Caco-2 cells. Caco-2 cells were transiently transfected with a 1.3-kb fragment of the promoter region of the DRA gene cloned into pGL2-Basic vector. At 24 h posttransfection, cells were treated with Bifidobacterium sp. CS (1:2 dilution) from the apical surface for 6 h (A) and 24 h (B). Promoter activity was measured by luciferase assay and normalized to β-galactosidase activity. Values are means ± SE of 3–4 independent experiments. *P < 0.05, **P < 0.01 vs. control.