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W FIRSHEIN

Publications and source records attributed to W FIRSHEIN.

13 recordsLinked to original sources
PubMed1965

INFLUENCE OF DEOXYRIBONUCLEIC ACID DEGRADATION PRODUCTS AND ORTHOPHOSPHATE ON DEOXYNUCLEOTIDE KINASE ACTIVITY AND DEOXYRIBONUCLEIC ACID SYNTHESIS IN PNEUMOCOCCUS TYPE 3.

Firshein, William (Wesleyan University, Middletown, Conn.). Influence of deoxyribonucleic acid degradation products and orthophosphate on deoxynucleotide kinase activity and deoxyribonucleic acid synthesis in pneumococcus type III. J. Bacteriol. 90:327-336. 1965.-An oligodeoxynucleotide fraction derived from a deoxyribonuclease-treated calf-thymus deoxyribonucleic acid (DNA) can enhance the activity of deoxycytidylic acid (dCMP) and deoxyguanylic acid (dGMP) kinases in cell suspensions of type III pneumococci. High levels of orthophosphate can produce similar effects. For part of the incubation period, the activity of dCMP and dGMP kinases is very low or undetectable in unsupplemented-cell suspensions of pneumococci. In contrast, the remaining kinases, deoxyadenylic acid and thymidylic acid, which are present in ample amounts in control and supplemented cells throughout the incubation period, are unaffected by the addition of oligodeoxynucleotides and orthophosphate. The stimulation of kinase activity is amino acid-dependent and can be abolished by adding chloramphenicol. When the oligodeoxynucleotide fraction and orthophosphate are further supplemented with all eight of the naturally occurring deoxynucleosides and deoxynucleotides (which do not affect kinase activity), a preferential enhancement of DNA synthesis occurs in comparison with cell growth or protein synthesis. Addition of deoxynucleosides and deoxynucleotides to unsupplemented cells produces only a slight increase in DNA synthesis. The preferential enhancement of DNA synthesis can be prevented by adding chloramphenicol at a certain time during incubation.

Amino Acids↗
PubMed1965

INFLUENCE OF DEOXYRIBONUCLEIC ACID DEGRADATION PRODUCTS AND ORTHOPHOSPHATE ON UPTAKE OF DEOXYNUCLEOSIDES IN PNEUMOCOCCUS TYPE 3.

Firshein, William (Wesleyan University, Middletown, Conn.), and Bernadette A. Gargan. Influence of deoxyribonucleic acid degradation products and orthophosphate on uptake of deoxynucleosides in pneumococcus type III. J. Bacteriol. 90:337-342. 1965.-The uptake of specific C(14)-deoxynucleosides by a type III encapsulated (virulent) strain of pneumococcus in resting-cell suspensions is enhanced when such deoxynucleosides are added as part of a supplement consisting of other deoxynucleosides, deoxynucleotides, an oligo(deoxy)nucleotide fraction derived from a deoxyribonuclease-treated calf-thymus deoxyribonucleic acid, and orthophosphate. Ribonucleic acid degradation products or yeast extract are ineffective in this respect. Mixtures of deoxynucleosides and deoxynucleotides stimulate uptake of a specific deoxynucleoside during early stages of incubation, whereas orthophosphate and, to a limited extent, the oligonucleotides stimulate uptake during later stages of incubation. The stimulated uptake of specific deoxynucleosides can be abolished by adding chloramphenicol.

Carbon Isotopes↗
PubMed1962

Population changes in Diplococcus pneumoniae.

Carta, G. (Wesleyan University, Middletown, Conn.) and W. Firshein. Population changes in Diplococcus pneumoniae. J. Bacteriol. 84:473-477. 1962.-Avirulent mutant strains derived from pneumococcal types I, II, III, and VII established themselves in initially virulent or predominantly virulent populations within 36 to 48 hr of incubation at 37 C in Brain Heart Infusion-blood broth. Aged blood-broth cultures or broth cultures lacking blood permitted a more rapid establishment of avirulent cells. This selective population change was due to a greater viability of avirulent than virulent cells, in the stationary phase, and to a toxic factor, produced by large numbers of avirulent cells, which inhibited the multiplication of virulent cells. Virulent cultures were stabilized, however, by the addition of mixtures of deoxynucleosides and deoxynucleotides, which prevented the establishment of avirulent cells.

Culture Media↗
PubMed1962

Effect of manganese and enzymatic deoxyribonucleic acid digests on population changes and respiration of Pneumococci.

Firshein, William (Wesleyan University, Middletown, Conn.). Effect of manganese and enzymatic deoxyribonucleic acid digests on population changes and respiration of pneumococci. J. Bacteriol. 84:478-484. 1962.-Deoxyribonucleic acid (DNA; Na salt) treated with deoxyribonuclease and Mn(++) (as MnSO(4)) stimulated R (avirulent) to S (virulent) population changes in vitro. Under certain environmental conditions and with certain strains, Mn(++) alone elicited these changes, but, in most cases, both digested DNA and Mn(++) were necessary for maximal effect. These population changes were due to a selective stimulation of the multiplication of S cells and a delay in S-cell lysis, with either a slight inhibitory effect or no effect against the multiplication of R cells. The magnitude of the population change depended upon the presence of digested DNA, the level of Mn(++), the strain, and the concentration of basal medium. Mn(++) enhanced respiration of S cells while inhibiting that of R cells.

DNA↗
PubMed1961

Effects of deoxyribonucleic acid products on deoxyribonucleic acid synthesis of virulent and avirulent pneumococci.

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.

DNA↗
PubMed1961

Effects of deoxyribonucleic acid products on respiration of virulent and avirulent pneumococci.

Firshein, W. (Wesleyan University, Middletown, Conn.). Effects of deoxyribonucleic acid products on respiration of virulent and avirulent pneumococci. J. Bacteriol. 82:181-186. 1961.-In the presence of deoxyribonucleic acid (DNA) + deoxyribonuclease + mixtures of deoxynucleosides and deoxynucleotides (supplement-1) which had previously been shown to enhance DNA synthesis in virulent (S) pneumococci without affecting such synthesis in avirulent (R) pneumococci, a significant enhancement of glucose oxidation was observed over control levels in S cells of types I, II, and III. In contrast, this supplement either depressed oxygen uptake or had no effect when R or weakly virulent (I) pneumococci were present. In the absence of glucose, S cells were unable to oxidize supplement-1 extensively, whereas R cells exhibited definite activity in this respect. Supplement-1 enhanced glucose oxidation specifically and was not oxidized in the process. The selective advantage produced by the DNA products in S cells could not be explained on the basis of nitrogen content, since a substance containing twice as much of this element as that found in the entire supplement did not enhance oxygen uptake to the extent that was observed with supplement-1.

Cell Respiration↗