Biomedical subjects

N V Apolonnik

Publications and source records attributed to N V Apolonnik.

3 recordsLinked to original sources

PubMedDate not supplied

[Electrical conductivity of isoionic DNA solutions].

Conductance of the DNA isoionic solutions obtained from aqueous solutions of its sodium salt using a column with mixed bed ionexchangers has been investigated. It has been found that in Kohlrausch's plots equivalent conductance slightly decreased with polymer concentration. Comparison of the degree of ionization (alpha) calculated from conductance measurements with those calculated from experimental pH values of isoionic solutions at different polymer concentrations revealed that the mobility of dissociating counterations decreases significantly under the influence of the electrostatic potential of the macroion.

DNA↗

PubMedDate not supplied

[Irreversible secondary structure changes in concentrated aqueous solutions of DNA].

"Aqueous" and "electrolytic" solutions of DNA from chicken erythrocytes different concentrations of NH4Cl have been investigated. Solutions of the first type were prepared from concentrated aqueous solutions of DNA and the second type solutions by solving a solid DNA in a supporting electrolyte. Studies of the melting curves showed that even the concentrated aqueous solutions of DNA were not completely native. The changes of the secondary structure of DNA caused by solving in deionized water are irreversible. This is confirmed by the abnormal dependence of melting temperatures of DNA on the ionic strength of aqueous solutions that is not characteristic for electrolytic solutions, that is not characteristic for electrolytic solutions. It has been shown that the type of dependence of the melting temperatures on the ionic strength is a more precise test of the secondary structure of DNA than a molar extinction or hyperchromic koefficient.

Ammonium Chloride↗

PubMedDate not supplied

[Effect of the nature of a monovalent counterion on the secondary structure of DNA is aqueous solutions].

Doxyribonucleates (DNMe) and deoxyribonucleic acid (DNA) were prepared by the ion-exchange method from Na+-salt from chicken erythrocyte DNA (DNS). (Here Me+ means Rb+, CS+, Na+, or NH4+). It was found that in aqueous solutions of DNMe in which the concentration of nucleic phosphorus was 8-10(5) mole/1 and the supporting electrolyte contained as an impurity only, the secondary structure of DNA was partly restored. This was confirmed by low values of the atomic extinction coefficient (epsilon260(p) = 6800 1/mole-cm and by high values of the hyperchromicity coefficients (1-28). The melting temperatures, as well as the width of the melting transition calculated from the melting curves, did not depend on the nature of Me+. Abnormally high melting temperatures for aqueous solutions of DNMe were noted. It was shown that the DNS - DNA transition was accompanied by spectrum changes that are typical of the denaturation process.

Ammonium Chloride↗