Requirements for transformation of the Challis streptococcus

Transformation of the group H streptococcus Challis was studied in a mixture of phosphate buffer and glucose supplemented with either free amino acids or nondialyzable peptides or both ingredients. Peptides were a requisite for development of competence. Marker integration and phenotypic expression of the acquired streptomycin-resistance character occurred when either peptides or amino acids were present in the medium. The yield of transformants, however, was optimal when both were available during the entire process of transformation.