Genetic transformation of Streptococcus sanguis. Further studies on the production and isolation of the competence factor.

Abstract

Two new media were developed, containing only the dialyzable components of Todd Hewitt broth (TH) with (medium II) or without (medium IV) inactivated horse serum. The two media were used to detect activity of the competence factor (CF) and the competence factor inactivator (CGI) of Streptococcus sanguis, and in preliminary experiments of CF isolation. Because all the dissolved substances with molecular weight (mol. wt.) less than 12,000 can be removed from these media by dialysis, leaving the CF and possible other high mol. wt. substances formed by growth in the dialysis tube, the use of these media should facilitate the isolation of CF and other high mol. wt. substances involved in genetic transformation of S. sanguis. Dialysis experiments suggest a mol. wt. greater than 12,000 of the CFs of the strains Challis and 13b. The CF of strain 13b was further isolated by Sephadex gel filtration and was eluted in the fractions of low mol. wt. compounds.