EFFECTS OF DEOXYRIBONUCLEIC ACID PRODUCTS ON DEOXYRIBONUCLEIC ACID SYNTHESIS OF VIRULENT AND AVIRULENT PNEUMOCOCCI

Abstract

Firshein , W. (Wesleyan University, Middletown, Conn.). Effects of deoxyribonucleic acid products on deoxyribonucleic acid synthesis of virulent and avirulent pneumococci. J. Bacteriol. 82: 169–180. 1961.—Cell suspensions of virulent pneumococci synthesize a greater amount of deoxyribonucleic acid (DNA) per cell in the presence of DNA + deoxyribonuclease + mixtures of deoxynucleosides and deoxynucleotides (supplement-1) than unsupplemented suspensions. Under identical conditions, avirulent and weakly virulent pneumococci do not respond to these DNA breakdown products. Glucose and casitone must be present for maximal effects to occur. A DNA turnover occurs in virulent cells. This has been demonstrated by a decrease in specific activity of H 3 -DNA extracted from virulent (S) cells exposed to nonradioactive supplement-1.