Deoxyribonucleic Acid Solutions Research Articles

The thermal properties of radicals formed in the radiolysis of frozen aqueous solutions of deoxyribonucleic acid

1. The radicals formed during radiolysis of DNA solutions have “specific” temperature ranges of existence. 2. In the investigated system, radical recombination is a complex process; this is indicated by the calculated kinetic parameters of radical recombination, which change with the heating temperature. 3. Kinetic measurements in irradiated solutions of DNA and 2-deoxyribose revealed a difference in the behavior of OH radicals with respect to these dissolved substances (with respect to the “carbohydrate” part of the DNA molecule and to 2-deoxyribose in the free state); this is attributed to the structural characteristics of the biopolymer molecule.

Flow dichroism of deoxyribonucleic acid solutions.

AbstractThe flow dichroism of dilute DNA solutions (A260 ≈ 0.1) has been studied in a Couette‐type apparatus with the outer cylinder rotating and with the light path parallel to the cylinder axis. Shear gradients in the range of 5–160 sec.−1 were studied. The DNA samples were whole, “half,” and “quarter” molecules of T4 bacteriophage DNA, and linear and circular λb2b5c, DNA. For the linear molecules, the fractional flow dichroism is a linear function of molecular weight. The dichroism for linear λ DNA is about 1.8 that of the circular molecule. For a given DNA, the dichroism is an approximately linear function of shear gradient, but with a slight upward curvature at low values of G, and some trend toward saturation at larger values of G. The fractional dichroism increases as the supporting electrolyte concentration decreases.

Losses due to Adsorption during Filtration of Aqueous Solutions of Polycyclic Aromatic Hydrocarbons

ALTHOUGH it has been pointed out that some adsorption of a solute may occur during filtrations1 there is apparently no general awareness of the possible magnitude of such losses with dilute solutions of certain solutes. Loss by adsorption of polycyclic, aromatic hydrocarbons during filtration2 or dialysis3 has been mentioned briefly, and such adsorption has been shown4 to be the cause of a major discrepancy in some recent attempts to determine the solubilities of such hydrocarbons in aqueous solutions of deoxyribonucleic acid (DNA)3,5–7. Stauff and Reske8 found filtration to be unsuitable for the removal of benzo[a]pyrene in determinations of solubility in aqueous protein solutions; they attributed the observed 20–50 per cent error to mechanical denaturation of the protein by the glass frit during filtration, but it is quite possible that adsorption of the hydrocarbon was also a contributing factor. Except for a brief investigation of the amount of protein adsorbed during the nitration of aqueous solutions through ‘Millipore’ filters9, however, there has been no detailed report on the extent of losses due to adsorption.

Turbulent-flow properties of deoxyribonucleic acid solutions.

MANY natural and synthetic high polymer solutions have lower friction in turbulent flow than the pure solvent1. In an effort to devise an experiment to explain the mechanism involved, flow studies were made using deoxyribonucleic acid (DNA) together with various carcinogens, steroids, acridine dyes, an antibiotic, and other materials which modify the effective molecular size, shape, and weight of the dissolved DNA. While the mechanism of friction reduction is still as elusive after these experiments as before, the interesting differences in turbulent flow properties of the various DNA-additive complexes may point to a simple way of estimating the effects of additives on the configuration of the DNA molecule.

Electric Polarization of Solutions of Rodlike Polyelectrolytes

A statistical-mechanical model for electrical polarizability of solutions of rodlike polyelectrolytes has been developed. The polyion is treated as a linear array of sites for adsorption of counterions. It is essentially the Rice—Harris model with an applied electric field. Calculation of the partition function of this system is performed by the matrix method and predictions are made for the effect on the low-frequency dielectric constant of added salt, degree of polymerization, and degree of neutralization. The results are in approximate agreement with measurements of solutions of polymethacrylic acid and deoxyribonucleic acid.

Electric Dichroism and Electric Birefringence of Deoxyribonucleic Acid in Solution and Deoxyribonucleic Acid-Crystal Violet Systems

ク形パルス法によりデオキシリボ核酸溶液(波長260mμ)およびデオキシリボ核酸クリスタルバイオレット系(波長590mμ)の電気二色性を電場の強さの関数として研究した。さらに同じ系の電気複屈折もあわせて測定した。いずれの量も低電場では電場の強さの1乗に比例し高電場では飽和に近づく傾向を示した。デオキシリボ核酸一クリスタル・ミイオレット系の電気二色性は高分子と色素の当量比がほぼ10に等しいときに極大を経過した。二色性の符号は負であった。これはクリスタルバイオレットの分子面がデオキシリボ核酸の分子軸に対し直角方向に結合していることを示す。最後に複屈折の測定におよぼす二色性の影響を論じた。

Infrared absorptions in the 1300 cm-1 region of deoxyribonucleic acid solutions with different base compositions.

Infrared absorptions in the 1300 cm-1 region of deoxyribonucleic acid solutions with different base compositions.

Deoxyribonucleic acids in solution. VI. Molecular weights of deoxyribonucleic acid fractions from hydrodynamic measurements

Deoxyribonucleic acids in solution. VI. Molecular weights of deoxyribonucleic acid fractions from hydrodynamic measurements

Deoxyribonucleic acids in solution. V. Heat denaturation of fractions and subunit structure of calf thymus DNA

Deoxyribonucleic acids in solution. V. Heat denaturation of fractions and subunit structure of calf thymus DNA

Dielectric properties of deoxyribonucleic acid solutions in salt water, formamide and urea

Dielectric properties of deoxyribonucleic acid solutions in salt water, formamide and urea

Chain regularity and flow dichroism of deoxyribonucleic acids in solution

AbstractDeoxyribonucleic acids (DNA's) extracted from several biological sources have been studied by means of the flow dichroism method, using the transparent coaxial cylinder apparatus. This study has two purposes: (1) to make clear the hydrodynamic behavior of the DNA chain, and the regularity in the orientation of purine and phrimidine bases about the molecular axis; and (2) to develop this particular flow dichroism method as an established device for the study of chain regularity of DNA and other chain polymers. The velocity gradient dependence of dichroism agrees well, to a first approximation, with the behavior of a model of a hydrodynamically equivalent ellipsoid in revolution. Differences between theoretical and empirical curves have been tentatively ascribed to the flexibility of the chain under consideration. Two kinds of data, 1 lie rotary diffusion coefficient and internal dichroism, have been evaluated by a graphical device in which the double logarithmic plots of reduced dichroism and velocity gradient of flow are compared with the theoretical curve. The data obtained have shown good reproducibility for DNA samples prepared by the same method from the same biological source. However, a remarkable difference in internal dichroism and rotary diffusion constant has been observed between DNA groups of different biological origin. The difference may be caused by fragmentation of DNA during the deproteinization procedure, bill the possibility that some of these differences originate in the biological source of the DNA cannot be denied. Orientation of purine and phrimidine bases in aqueous solution is found to be quite regular in direction, as predicted by the Watson–Crick model. Dichroic spectra have shown that the direction of the oscillator dipole corresponding to the 260 mμ absorption band has a different angular relationship to the helical axis than the oscillator dipole for the 220 mμ band.

PAINFUL SUBCUTANEOUS HEMORRHAGES OF THE EXTREMITIES WITH UNUSUAL REACTION TO INJECTED DEOXYRIBONUCLEIC ACID.

Case Studies1 May 1964Painful Subcutaneous Hemorrhages of the Extremities with Unusual Reaction to Injected Deoxyribonucleic AcidADAM S. LITTLE, M.D., F.R.C.P., HAROLD E. BELL, M.D.ADAM S. LITTLE, M.D., F.R.C.P.Search for more papers by this author, HAROLD E. BELL, M.D.Search for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-60-5-886 SectionsAboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail ExcerptIn 1961, Levin and Pinkus (1) reported the case of a 40-year-old Negro woman who for 4 years had suffered from acute and painful ecchymoses confined to her extremities. The lesions were preceded by a wheal which soon became hemorrhagic. The longest asymptomatic period in the 4 years had been 4 days. The intradermal injection of a solution of the patient's lysed leukocytes and a solution of deoxyribonucleic acid (DNA) obtained from calf thymus gland each produced hemorrhages in the skin of the extremities but failed to do so in the skin of the trunk. Similar injections using ribonucleic acid...

CONCENTRATION EFFECTS IN MEASUREMENTS OF SODIMENTATION VELOCITY AND VISCOSITY OF DEOXYRIBONUCLEIC ACID SOLUTIONS.

THE dependence on concentration of the hydrodynamic properties of DNA solutions has been the subject of some recent publications1–4. It has been shown in particular1, that under specified conditions the dependence on concentration of the reduced viscosity and the sedimentation coefficient of aqueous DNA solutions may be expressed by empirical formulae that are formally analogous to those found to apply for most uncharged polymer solutions, namely: In these equations the symbols s and s0 represent the sedimentation coefficients at concentration c and zero respectively. ηsp/c and [η] are the corresponding reduced viscosity values and α and k are dimensionless constants.

Deoxyribonucleic acids in solution. IV. Subunits in deoxyribonucleic acid from calf thymus

Deoxyribonucleic acids in solution. IV. Subunits in deoxyribonucleic acid from calf thymus

ACTINOMYCIN BOUND TO DEOXYRIBONUCLEIC ACID IN SOLUTION.

ACTINOMYCIN BOUND TO DEOXYRIBONUCLEIC ACID IN SOLUTION.

Deoxyribonucleic acids in solution. I. Fractionation and characterisation of fractions

Deoxyribonucleic acids in solution. I. Fractionation and characterisation of fractions

Deoxyribonucleic acids in solution. III. Reversible time changes in streaming birefringence

Deoxyribonucleic acids in solution. III. Reversible time changes in streaming birefringence

Flow birefringence in solutions of deoxyribonucleic acid—III. Dependence of the optical anisotropy of deoxyribonucleic acid molecules on the molecular weight

Flow birefringence in solutions of deoxyribonucleic acid—III. Dependence of the optical anisotropy of deoxyribonucleic acid molecules on the molecular weight

The Stability of Deoxyribonucleic Acid Solutions Under High Pressure.

The Stability of Deoxyribonucleic Acid Solutions Under High Pressure.

VISCOSITY OF DEOXYRIBONUCLEIC ACID SOLUTIONS IN THE 'SUB-MELTING' TEMPERATURE RANGE.

DEOXYRIBONUCLEIC acid (DNA) ‘melting’ has been mainly investigated using spectroscopic and optical rotation techniques1. To our knowledge, the viscosity behaviour associated with the ‘melting’ phenomenon has been examined only in the special cases of synthetic deoxyribopolynucleotides2 and phage DNA3. In an investigation of this subject, using DNA preparations from three different sources, it was observed that the change in intrinsic viscosity parallels the change in optical density at 260 mµ, except for the ‘sub-melting’ temperature range. The peculiar behaviour found in this region is reported here. Briefly, this is characterized by a fall in viscosity which is completely reversed on cooling and seems to be caused by the local melting of deoxy-adenylic-thymidylic (dA-T) clusters.