[Effect of a substituent origin in actinocin amides on their binding to DNA].

The results of studies on the structure of complexes of DNA with compounds based on the actinocin chromophore, a center of binding of the antitumor antibiotic actinomycin D to DNA, were analyzed. In positions 1 and 9 of the chromophore of these compounds, pentapeptide lact ones of actinomycin D are replaced by groups of various origin. By using spectral, optical, and hydrodynamic methods a model of binding to DNA for each compound was constructed, and some regularities of complex formation depending on the structure of actinocin substituents and the amount of ligands in the complex were revealed.

[Interactions of DNA with ampholytes based on actinocin].

The interaction of DNA with actinocin monoamides containing a substitute with the cationoide center in one of the amide groups were studied by spectrophotometry, induced circular dichroism, viscometry and flow birefringence methods. At pH values of solution exceeding their isoelectric point, these substances, which are in nature ampholytes, occur as zwitterions. At lover pH values they occur in the cationoid form.

[Interaction of DNA with actinocyl-bis-thiazole].

The DNA complexes with actinocyl-bis-bithiazole have been investigated by spectrophotometry, viscometry and flow birefringence. It was estimated, that at low degrees of binding (r < or = 0.07) this compound binds to DNA by bisintercalation via bithiazole groups located in positions 1 and 9 of the phenoxazone chromophore.

[Biochemical bases of adverse reactions to antibacterial preparations used in renal tuberculosis and means of their prevention].

Factors leading to development of adverse reactions to antituberculous drugs in patients with nephrophthisis were studied and complex treatment regimens to prevent the reactions were developed. The use of such regimens along with chemotherapy allowed the frequency of adverse reactions to be lowered almost 2-fold in patients with limited nephrophthises and to postpone the development of adverse reactions in patients with extended tuberculosis for 1-1.5 months.

[DNA interaction with low molecular weight ligands of different structure. III. DNA complexes with distactins].

The DNA complexes with distactins have been investigated by means of spectrophotometry, viscosimetry and flow birefringence methods. The distactins are actinocin's derivatives containing in the 1,9 positions of the phenoxazone moiety oligopyrrolcarboxamide groups (like those of distamycin A), which have from one to three fragments of 1-methyl-4-amino-2-pyrrolic acid. The mode of DNA-distactins binding in water solution depends on the quantity of the methylpyrrole rings in the oligopeptide groups.

[DNA interaction with low molecular ligands of different structure. II. Complexes of DNA with actinomine and its analogs].

DNA-complexes with actinomine and its analogues containing omega-dialkylaminoalkyl groups at 1,9 positions of the phenoxazone moiety were studied by technique of spectrophotometry, viscometry and flow birefringence. In the process of spectrophotometry titration two groups of spectra corresponding to different DNA--ligand ratio in a complex were observed. According to the experimental data the investigated compounds are bounded to DNA by means of intercalation and external binding.

[Interactinos of DNA with low molecular weight ligands of various structures. I. Complexes of DNA with actinomycin and its simple analogs].

The DNA complexes with actinomycin D and its simple analogues have been investigated by means of spectrophotometry, viscometry and flow birefringence methods. The number of binding sites per base pair of ligand on DNA depends on the nature of substitute in 1.9 position of the phenoxasone chromophore.

[The effect of acridine dyes on the molecular structure of DNA].

DNA--acriflavin complexes have been investigated by the methods of flow birefringence and viscometry. The intrinsic viscosity and the optic anysotropy of the complex increase with the increasing quantities of binding dye. Experimental data are treated on the basis of different models of binding.