[Interaction of Ag+ ions with DNA and its monomers].

Differential UV spectra of DNA and its monomers that were induced by Ag+ ions were measured, and the effect of ions on the parameters of the helix-coil transition was studied. The data obtained confirm the existence of "strong" and "weak" modes of binding of Ag+ to DNA. The earlier proposed proton transfer from N1G to N3C, which is determined by the interaction of Ag+ with N7G (a "strong" complex), follows immediately from the shape of the differential UV spectra.

[Interaction of Ag+ ions with ribonucleotides of canonical bases].

The interaction of Ag+ ions with ribonucleotides of canonical bases in aqueous solution was studied by differential UV spectroscopy. Atoms coordinating silver ions (N7, O6 of guanosine 5'-monophosphate, N3, O2 of cytidine 5'-monophosphate, N7, N1, N3 of adenosine 5'-monophosphate and N3 of uridine 5'-monophosphate) and the binding constants characterizing the formation of appropriate complexes were determined. The differences in the relative affinity of Ag+ ions for the atoms of nucleotide bases correlate with the potential on them.

[Interaction of divalent cadmium ions with nucleotides and native DNA].

Complex formation of Cd2+ ions with 2'-deoxy-5'-phosphates of canonical bases and their riboanalogues in water solution is studied by the method of differential UV-spectroscopy. It is stated that the atoms coordinating Cd2+ in complexes are N7 of dGMP and GMP, dAMP and AMP, N1 of adenine derivatives, N3 of dCMP. No interaction with base heteroatoms of UMP and dTMP is found.

Interaction of bivalent copper, nickel, manganese ions with native DNA and its monomers.

UV differential spectroscopy is applied to study the interaction of Cu2+, Ni2+, Mn2+ ions with deoxyribonucleotides of canonic bases (dGMP, dAMP, dCMP, dTMP) and native DNA. Heteroatoms of the bases, coordinating ions, and binding constants which characterize the formation of metal complexes are found. The affinity of the ions is lower for the deoxyribonucleotide bases than for the ribonucleotide ones.

[Effect of nitrobenzene and its chlorine derivatives on antioxidative homeostasis].

Nitrobenzene, o-nitrochlorobenzene and p-nitrochlorobenzene were studied in experiments with rats for their effect on intensity of lipid peroxidation (LPO), antioxidative activity (AOA), vitamin E content in the spleen and liver tissues as well as on certain hematological parameters of animals. These substances, when applied in acute experiments, deteriorate hematological parameters, intensify LPO in the spleen tissues. In this case AOA and vitamin E concentration grow.