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Biomedical subjects

V I Salianov

Publications and source records attributed to V I Salianov.

At least 19 recordsLinked to original sources
PubMed1990

[Study of the properties of condensed forms of the complexes of linear and supercoiled DNA with mitoxantrone and bisantrene].

The effect of anthrachinone and anthracene derivatives on linear and circular superstranded molecules of DNA in conditions of their condensation was studied. It was shown that the compounds formed strong intercalation complexes with the molecules of the linear and circular superstranded DNA when the DNA molecules were in the condensed condition. The optical properties of the disperse liquid crystal phases formed of the complexes of the investigated compounds with the molecules of linear double-chain DNA differed. Moreover, the optical properties of the condensed phases formed of the complexes of the compounds with the molecules of linear and circular superstranded DNA also differed. The causes of the differences are discussed.

Anthracenes↗
PubMed1988

[DNA liquid crystals as a possible system of testing the interactions between DNA and biologically active compounds of platinum (II) and various antibiotics].

DNA liquid crystals forming in water-salt solutions containing polyethylene glycol were used as a system for testing consequences of reactions of antitumor compounds belonging to two different groups with molecules of nucleic acids. It was found that with due account of the level of DNA molecule filling with daunorubicin it was possible to form two cholester phases characterized by the textures of "finger prints" and CD spectra with intensive bands of unlike signs, as well as the nematic phase characterized by the texture of the "black twisted fiber" system and the absence of the CD spectrum intensive band. Modification of the DNA molecules resulting from the reaction with cysdichlorodiamine platinum (II) led to formation of a new liquid crystalline phase with properties differing from those of the liquid crystalline phases of the cholester or nematic type.

Antibiotics, Antineoplastic↗
PubMed1983

[Characteristics of the circular dichroism spectra of liquid crystals formed from DNA complexes with antibiotics].

Compact particles were formed from low molecular DNA in water-salt solutions (0.3 M NaCl, pH 6.7) containing polyethylene glycol. The DNA molecules in these particles were in the mesophase (liquid crystalline) state characterized by an intensive negative bond in the circular dichroism (CD) spectrum. Binding of DNA to anthracycline antibiotics (daunomycin, aclacynomycin), oligopeptide antibiotics (distamycin, nethropcin) and ethidium bromide with subsequent formation of liquid crystals from such complexes was accompanied by appearance of CD spectra with characteristic features of the respective antibiotic groups. The characteristic features of the CD spectra allowed distinguishing various antibiotics.

Anti-Bacterial Agents↗
PubMed1982

[Changes in the spatial organization of DNA molecules induced by anthracycline antibiotics].

The optical properties of the mesophases modeling the condensed state of cell DNA molecules formed from the complexes of 7-anthracycline antibiotics with double-stranded low-molecular DNA and polynucleotides were studied. The parameters of the antibiotic binding to the DNA during formation of the mesophases (0.3 M NaCl, 150 mg/ml of polyethylene glycol) are presented. It was found that the CD mesophase spectrum formed from the complex of DNA-antibiotic was characterized by the presence of intensive negative bands in the region of absorption of the chromophores of both DNA and antibiotic. This is indicative of regular spiral organization of the DNA mesophase. Binding of the antibiotic to DNA and polynucleotides was accompanied by changing of the band negative mark (at definite levels of the DNA molecule filling with the antibiotic) in the CD mesophase spectrum to the positive one. It was shown that with respect to the mesophases formed from the complexes of DNA with iremycin and aclacinomycin A no changing in the band marks was observed. Consequently, antibiotics may be conditionally divided into 2 groups. The antibiotics of the first group induce changes in the spin direction of the DNA mesophase, while the antibiotics of the second group had no such effect. It was demonstrated that antibiotic binding with the AT-rich sequences induce more pronounced changes in the mesophase properties than that with the GC-rich sequences. Possible causes of the mark changing in the spin of the DNA mesophase during the DNA binding with antharcyclines are discussed. Biological significance of the phenomenon is still unclear.

Aclarubicin↗
PubMed1979

[Compaction of 2-chain DNA as a method of procedure in determining its binding constant with antibiotics].

The binding of antibiotics and dyes with a compact form of DNA produced in water-salt solutions containing polyethylenglycol (PEG) presents a possibility of studying antibiotic interaction with DNA molecules contained in biological objects, such as viruses and chromosomes, since the compact form of DNA reflects some DNA properties in vivo. Possibly the use of the compact and not the "open" or linear form of DNA in chemical reactions will provide data on the efficiency of the compound "action" under conditions close to intracellular ones. The results well be useful in screening substances with "optimal" pharmacological effect. The paper presents a method for determination of the constant of antibiotic or dye binding with DNA and two-chain synthetic polynucleotides in water-salt solutions containing PEG. The method is based on "elimination" of the DNA molecules in the form of compact particles bound in a complex with an antibiotic or a dye. Comparison of the data with the results of estimation of the constants of antibiotic binding with DNA by the routine methods showed close conformity of the binding constants determined by different methods. It was found that the value of the binding constant of the antibiotics studied slightly depended on the structural state of DNA. The value was practically the same for the linear and the compact forms of DNA.

Anti-Bacterial Agents↗
PubMedDate not supplied

["Phantom" structure of solvents and packing of dual-chain nucleic acid molecules in liquid crystal dispersion particles].

The properties of mesomorphic dispersions of double-stranded nucleic acids were studied. A comparison of these properties indicates that their diversity cannot be explained unambiguously in terms of the conception of Van-der-Waals interactions in particles of mesomorphic dispersions without regard for the specific properties of the solvent, water, in the vicinity of adjacent nucleic acid molecules. It was assumed that, with small distances between the molecules of nucleic acids, a specific "phantom" structure of the solvent appears in their vicinity, which acts as an elastic medium that modifies the interactions between nucleic acid molecules and as a medium in which a collective tunneling of protons can occur. The combination of the two effects determines the "recognition" of nucliec acid molecules and the stabilization of the cholesteric structure of mesomorphic dispersions of nucleic acids.

Crystallization↗
PubMedDate not supplied

[Formation of liquid-crystalline dispersions of double-stranded DNA-chitosan complexes].

Right-handed helical double-stranded DNA molecules were shown to interact with chitosans to form under certain conditions (chitosan molecular weight, content of amino groups, distance between amino groups, ionic strength and pH of solution) cholesteric liquid-crystalline dispersions characterized by abnormal positive band in CD spectrum in the absorption region of DNA nitrogen bases. Conditions were found for the appearance of intense negative band in CD spectrum upon dispersion formation. In some cases, no intense band appeared in CD spectrum in spite of dispersion formation. These results indicate not only the multiple forms of liquid-crystalline dispersions of DNA-chitosan complexes but also a possibility to control the spatial properties of these complexes. The multiplicity of liquid-crystalline forms of DNA-chitosan complexes was attempted to explain by the effect of character of dipoles distribution over the surface of DNA molecules on the sense of spatial twist of cholesteric liquid crystals resulting from molecules of the complexes.

Chitin↗
PubMedDate not supplied

[A compact form of DNA in solution. III. Influence of the ion composition of the solution on the compactization process of double-stranded DNA in the presence of peg].

The data showing the features of the DNA compactization process in PEG-containing solutions of chlorides of different alkaline metals (LiCl, KCl, RbCl and CsCl) and an ammonium salt (CH3-(CH2)17-N-(CH3)3Br) are presented. The data indicate that the formation of a compact form of the double-stranded DNA in PEG-containing water-salt solutions depends not only on the PEG concentration and ionic strength but on tha cation nature as well. The compactization occurs most easily in the presence of Na+-ions. This indicates a specific character of interaction between Na+-ions and DNA phosphate groups which may be due to an optimum structural fit between the hydrated Na+-ions and orientation of the phosphate groups in the DNA molecule. The nature of forces involved in the processes of the intramolecular compactization and intermolecular aggregation of double-stranded DNA molecules in water-salt solution is discussed. The difference between the effect of Na+ and that of K+-ions on the compactization process at the ionic strengths close to physiological values makes it possible to suggest that the changes of the tertiary structure of double-stranded DNA which accompany its function in vivo may take place under conditions of a decreased water activity at the expense of relatively slight changes in ion composition of the water surrounding DNA.

Binding Sites↗
PubMedDate not supplied

[Effect of intercalators on the properties of liquid-crystalline dispersions of nucleic acid-chitosan complex].

Molecules of deoxyribonucleic acid and synthetic polydeoxyribonucleotides (NA) in the particles of liquid-crystalline dispersions resulting from interaction with chitosan are accessible to interaction with intercalators. The intercalation is accompanied by alteration in the direction of spatial twist of cholesterics of NA-chitosan complexes. This effect is absent in the case of "classical" cholesterics produced from NA molecules via phase exclusion, i.e., the cholesteric structure of NA-chitosan complex is very "labile" as distinct from "classical" cholesteric NA.

Chitin↗
PubMedDate not supplied

[Some X-ray diffraction parameters of liquid-crystalline dispersions of nucleic acid-chitosan complexes ].

Liquid-crystalline dispersions of nucleic acid-chitosan complexes (NA-chitosan) possess optical and X-ray diffraction properties different from those of "classical" cholesterics. It is possible that positive charge distribution (distance between charges, chitosan conformation, etc.) in the polymeric chain of chitosan molecule combining with NA molecule is the factor that affects the spatial structure of resulting dispersions.

Chitin↗
PubMedDate not supplied

["Bridge" structures between nucleic acid molecules fixed in the structure of a liquid crystal].

The binding of daunomycin and copper ions to poly(I).poly(C) molecules fixed in a particle of a liquid-crystalline dispersion was studied. A thermodynamic model of adsorption was developed, which makes it possible to describe the formation of complexes of a particular kind, "bridges" that connect adjacent nucleic acid molecules fixed in a liquid crystal. The bridges represent chelate complexes, which incorporate the molecules of the antibiotic daunomycin and copper ions. Equations describing the dependence of the concentration of these bridges in solution on the concentration of their constituents were derived. The family of dependences of experimental amplitudes of bands in CD spectra typical of "bridge" structures on the concentration of copper ions represents a set of S-shaped curves, and, as the concentration of daunomycin in solution increases, the level of saturation of these curves increases. The analysis of experimental data with the use of this model suggests that the structures of this type compete with daunomycin molecules for the binding sites on poly(I).poly(C). By using this model, the energies of formation of bridge structures were calculated.

Adsorption↗