Figure 2.

Analysis of β-galactosidase activity and Nov^R DNA contents in the same supernatant. Samples were taken at regular intervals during growth in CAT and induced to competence by adding 250 ng/ml of CSP-1. Uninduced samples, receiving no peptide pheromone, were run in parallel as negative controls. A and B show the results of two separate experiments that otherwise are identical. Closed squares and open squares represent β-galactosidase activity in cell-free supernatants from competent and noncompetent cultures, respectively. Closed circles represent the number of transformants obtained per ml when novobiocin-sensitive pneumococci were transformed with cell-free supernatant from competence-induced EK4167 (Nov^R) cultures. Open circles represent the negative control, showing the number of transformants obtained with cell-free supernatants from noncompetent EK4167 (Nov^R) cultures. β-Galactosidase activities are given in Miller units and are the means ± SEs of triplicate samples. Where error bars are not visible, the SE was within the area occupied by the symbol.