TRANSFORMATION OF STREPTOCOCCI TO STREPTOMYCIN RESISTANCE

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Abstract
Perry, Dennis (Northwestern University Medical School, Chicago, Ill.) and Hutton D. Slade . Transformation of streptococci to streptomycin resistance. J. Bacteriol. 83: 443–449. 1962.—A total of 43 strains of streptococci, belonging to serological groups A, B, C, D, E, F, G, H, K, L, M, N, O, and Q, and three ungroupable strains were exposed to deoxyribonucleic acid (DNA) extracted from streptomycin-resistant streptococci belonging to groups A, C, D, G, H, and ungroupable strains. Transformation to streptomycin resistance was obtained with streptococci belonging to groups F, H, and O and a serologically unclassifiable streptococcus. The transformable streptococci incorporated DNA from both homologous and heterologous groups and strains of streptococci. Certain strains within a group served as DNA donors but not as DNA recipients, and certain strains served as DNA donors for some strains but not for others. Even within an individual group, not all strains were transformable. The number of transformants was influenced by the source of DNA and the DNA recipient strain used. Substances which affect cell permeability did not enable transformation to occur. Radioisotope studies with P 32 -labelled DNA showed that nontransformable strains incorporated amounts of DNA comparable to the transformable strains.