FIG. 3.
Quantification of the competence for DNA transformation in N. meningitidis comP, pilT, pilT2, pilU, pilV, pilX, and pilZ mutants. The WT strain and a nonpiliated pilD mutant were included as positive and negative controls, respectively. Equivalent numbers of recipient cells were transformed using 1 μg of chromosomal DNA purified from a Rifr strain, and Rifr transformants were counted. Results are expressed as percentages of recipient cells transformed and are the means ± standard deviations from four to six independent experiments.