Figure 3.

Increased reuterin production followed by modification of the CRE region upstream of the pdu operon. (A) Schematic overview of the transcriptional regulatory elements located upstream of the pdu operon as determined before in L. reuteri wild type (top).³¹ Grey rectangles indicate the predicted -35 and -10 regions, the red dot indicated the transcriptional start, boxed sequence represents the catabolite response element (CRE), the green rectangle represents the Shine-Dalgarno sequence, and ATG is the translational start site. Bottom: upon incorporation of oJP675 six adjacent bases are modified in the CRE region. The newly incorporated sequence is italicized and underlined. (B) Reuterin minimum inhibitory concentration assay with L. reuteri wild type and RPRB3007. Cells were harvested at growth phases representative for the mid-logarithmic phase (OD₆₀₀ = 0.6) or stationary phase (OD₆₀₀ = 2) followed by a reuterin assay, a minimum inhibitory concentration assay, and conversion to Units reuterin per ml as described in Materials and Methods. The Units reuterin/ml for the wild type strain (black bars) and strain RPRB3007 (gray bars) were determined for both growth phases. Asterisks indicates statistical significance (p < 0.05). Data presented are averages of three independent experiments, and error bars indicate standard deviation.