FIG. 7.

Effects of cph1 and cpl1 genes on the growth of S. pneumoniae. (A) Cultures of M31(pLSE1) (•), M31(pAMR21) (▪), and M31(pAMR22) (▴) were incubated at 37°C. Pneumolysin release to the periplasmic fraction was measured, as explained in Materials and Methods, for M31(pLSE1) (○) and M31(pAMR21) (□) cultures. N, nephelometric units; OD₅₄₁, optical density at 541 nm. (B) Viabilities of the same cultures obtained after plating two appropriate dilutions on C medium.