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 pneumococei 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 H3-DNA extracted from virulent (S) cells exposed to nonradioactive supplement-1.

Biodynamic effects of oligonucleotides.

“…Thus, with essentially "resting" pneumococci and streptococci, it was observed that supplementation of the medium with DNA fragments plus the building stones of DNA (mixtures of deoxyribonucleotides and deoxyribonucleosides) resulted, within 70 min, in a striking stimulation of DNA synthesis. This stimulation was not accompanied by any comparable stimulation of RNA or protein synthesis (22,23,26,32).…”

“…The stimulatory effect of DNA fragments on the multiplication of virulent pneumococci and streptococci was found to be associated with a stimulation of DNA synthesis in cell populations that were maintained in minimal media (22,23,26,32). Thus, with essentially "resting" pneumococci and streptococci, it was observed that supplementation of the medium with DNA fragments plus the building stones of DNA (mixtures of deoxyribonucleotides and deoxyribonucleosides) resulted, within 70 min, in a striking stimulation of DNA synthesis.…”

“…This was revealed by assaying the components of the supplementation separately. Such tests showed that the oligodeoxyribonucleotides, present in the enzymatic digest of calf thymus DNA, exert an influence on DNA synthesis that is far in excess of the concentration of their components present in the monomer form (23). Also, the oligomer-dependent stimulation occurs within a very narrow range of concentrations; maximal effects are obtained with concentrations only slightly higher than those giving any effect at all.…”

“…The stimulatory effects of DNA fragments on DNA synthesis in pneumococci are inhibited by chloramphenicol (26), or by an omission of amino acids or glucose from the minimal medium on September 8, 2020 by guest http://mmbr.asm.org/ Downloaded from (23). The stimulatory effects are also inhibited by a number of analogues of DNA, including 2mercapto-6-aminopurine and 2-acetylamino-5nitrothiazole, and by a cyclopentyl pyrimidine derivative (29).…”

Influence of Deoxyribonucleic Acid Degradation Products and Orthophosphate on Uptake of Deoxynucleosides in Pneumococcus Type III

“…Encapsulated (virulent) pneumococci of several types synthesize deoxyribonucleic acid (DNA) at a rate greater than that for synthesis of protein and ribonucleic acid (RNA) in resting-cell suspensions supplemented with DNA degradation products and orthophosphate (Firshein, 1961(Firshein, , 1965. The DNA degradation products capable of stimulating DNA synthesis in virulent strains consists of an oligo(deoxy)nucleotide fraction (derived from a deoxyribonuclease-treated calfthymus DNA) further supplemented with all eight of the naturally occurring deoxynucleosides and deoxynucleotides.…”