FIGURE 6.

Deletion of the pezAT operon increases genetic competence. The development of spontaneous competence of both pneumococcal wt and pezAT mutant cells were assessed by measuring, at different pH, the transcriptional level of Photinus pyralis luc gene that was fused downstream of the promoter of ssbB, which is a late competent gene. Gray lines indicate growth curves at OD₄₉₂, whereas black lines depict RLUs/OD₄₉₂, ranging from pH 7.7–7.9. Vertical line joining both panels points the time differences in the onset of the main peaks of competence. Values correspond to individual cultures representative of three independent experiments (Caymaris et al., 2010).