FIG 1.

Heterologous expression of BmrR with nisin induction detected by SDS-PAGE and the survival of L. lactis BmrR and L. lactis NZCK1 after ox bile challenge. (A) Soluble extracts were analyzed on 12% denaturing SDS-PAGE gels. Lane M, dual-color-prestained broad-molecular-size protein markers (10 to 180 kDa); lane 1, L. lactis NZCK1 without nisin induction; lane 2, L. lactis BmrR without nisin induction; lane 3, L. lactis NZCK1 with nisin (10 ng·ml⁻¹) induction; lane 4, L. lactis BmrR with nisin (10 ng·ml⁻¹) induction. The red arrow indicates the overexpressed BmrR. (B) The survival rate was calculated as the ratio of the number of colonies obtained on GM17 plates after and before ox bile treatment. (C) The bile acid content inside L. lactis BmrR was determined after ox bile treatment. Data are reported as means ± standard deviations (SDs) from at least three independent experiments and were analyzed by an unpaired, two-tailed Student's t test. *, P < 0.05; ****, P < 0.0001.