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Biomedical subjects

Iu V Dudnik

Publications and source records attributed to Iu V Dudnik.

At least 37 records · Page 2Linked to original sources
PubMed1984

[Regeneration of Nocardia orientalis protoplasts].

A method for effective regeneration of the protoplasts of N. orientalis, a vancomycin-producing organism into viable cells on a rich organic medium was developed. The dependence of the regeneration on the conditions of the protoplast plating out and the level of the regeneration medium dehydration was studied. The highest positive effect was observed when the protoplasts were suspended in the agarized medium and then plated out on the regeneration medium dehydrated by 2.5 per cent. The frequency of the protoplast regeneration increased on addition of bovine serum albumin to the regeneration medium. The effect of bovine serum albumin depended on its concentration. When the albumin concentration was optimal (0.01 per cent) the regeneration amounted to 100 per cent.

Culture Media↗
PubMed1984

[Isolation and regeneration of Micromonospora olivoasterospora protoplasts].

The conditions for preparation and regeneration of the protoplasts of M. olivoasterospora were developed. It was found that effective formation of the protoplasts required preliminary cultivation of M. olivoasterospora in the medium containing glycine in a concentration inhibiting its growth at least by 60-80 per cent. The strains studied markedly differed in their sensitivity to glycine and were highly sensitive to it. The efficacy of the protoplast formation depended on the culture age and increased with the use of the lytic enzyme 3 of Cytophaga dissolvens. The possibility and advisability of the use of prolonged lysis of the Micromonospora cell walls were shown. A rich organic medium was used for regeneration of the protoplasts.

Cell Fractionation↗
PubMed1983

[Interaction with DNA of semisynthetic carminomycin and rubomycin derivatives].

The apparent binding constants and the effect of semisynthetic derivatives of carminomycin and rubomycin (anthracycline antibiotics) on DNA fusion were studied. The following semisynthetic derivatives were used. 13-dihydrocarminomycin, 14-hydroxycarminomycin, 13-(4-methylpiperazinyl) imine carminomycin, 13-benzoylhydrazone carminomycin (carminazone), 13-tret-butoxycarbonyl hydrazone rubomycin, 13-(4-methylpiperazinyl) imine rubomycin, 14-(1-hydroxyl-2,2,6,6-tetramethylpiperidyl-4)-acetoxyrubomycin (spin-labeled rubomycin). The above derivatives slightly differed from the initial antibiotics by their affinity to DNA. The binding constants of methylpiperazinyl imines was 2-3 times higher than those of the respective antibiotics.

Adsorption↗
PubMed1980

[Nucleotide specificity of sibiromycin interaction with DNA].

Sibiromycin binds selectively to poly(dG).poly (dC) and poly(dG--dC).poly (dG--dC) and does not interact with poly(dA--dT).poly(dA--DT), poly (dI).poly (dC) and poly(dI--dC).poly(dI-dC) as is evident from the changes in the UV spectrum of the antibiotic at 310 mn, differential CD spectrum and inhibition of the template activity of polynucleotides in the DNA-dependant RNA-polymerase system. Sibiromycin efficiently interacts with GC-rich DNA specifically methylated at N-7 of guanine and glucosilated DNA of T2 phage. Therefore, specific interaction of sibiromycin with the guanine sites may take place rather in the narrow groove than in the large groove of the double helix.

Aminoglycosides↗
PubMed1978

[Density gradient ultracentrifugation method of studying sibiromycin interaction with linear and circular DNA].

Sibiromycin added to linear chromosomal E. coli DNA in vitro leads to the decrease of bouyant density in neutral CsCl density gradient. This decrease is a linear function of sibiromycin/DNA ratio and amounts to about 32 mg/ml at the ratio equal to 0.1. Binding sibiromycin does not change the degree of hydration of DNA as revealed by centrifugation in metrizamide density gradients. When added to the covalently closed or open circular DNA of PM-2 phage, sibiromycin decreased the bouyant density of these DNA species to a similiar extent. The antibiotic does not induce single-strand breaks in DNA in vitro as follows from the results of ethidium bromide-CsCl density gradient centrifugation of covalently closed PM-2 DNA.

Antibiotics, Antineoplastic↗
PubMed1978

[Distribution of 3H-carminomycin in the body of mice].

Distribution of 3H-carminomycin with the specific activity of 390 mCu/g prepared by the method of isotope exchange in 3H2O was investigated on mice treated with the antibiotic administered intravenously in a dose of 2 mg/kg. It was shown that the antibiotic rapidly accumulated in the mouse tissues, mainly in the liver, kidneys, lungs and spleen. The carminomycin blood levels markedly decreased within the first 5 minutes after the drug administration and remained rather stable during the following 6 hours. The concentrations of carminomycin in the heart muscle were comparatively low. Still, at early periods they were much higher than those in the skeletal muscles. The difference disappeared by 24 hours. Carminomycin penetrated into the tissues of the brain.

Animals↗
PubMed1978

[Effect of microbial and tumor cell adaptation to rubomycin on their uptake of rubomycin and carminomycin].

Anthracycline antibiotics rubomycin (daunomycin) and carminomycin rapidly accumulated in the bacterial and ascitic tumor cells and their intracellular concentrations significantly exceeded the concentrations in the medium. The strains of Staph. aureus and Fisher mouse ascitic lymphadenosis L-5178/P resistant to rubomycin preserved sensitivity to carminomycin. The resistance of the bacterial and tumor strains to rubomycin was accompanied by a significant decrease in the accumulation of rubomycin in the cells. At the same time carminomycin also effectively accumulated in the cells of Staph. aureus and Fisher ascitic lymphadenosis adapted to rubomycin, the same as in the cells of the parent strains.

Adaptation, Physiological↗
PubMed1977

[Role of the functional groups of the sibiromycin molecule in DNA binding].

Biological activity of 2 derivatives of sibiromycin, an antibiotic close by its chemical structure to antramycin and their capacity for formation of complexes with DNA was studied. Anhydrosibiromycin like sibiromycin formed a complex with DNA. The antibiotic increased the DNA melting point but to a less extent than sibiromycin. Anhydrosibiromycin had a low activity in the system of DNA-dependent RNA-polymerase. The low biological activity of anhydrosibiromycin must be due to instability of the antibiotic complex with DNA. Methyl ether of sibiromycin by the phenol hydroxyl, the other derivative of sibiromycin had no biological activity and did not interact with DNA. On the basis of experimental data it was suggested that definite functional groups of the sibiromycin participated in DNA binding.

Antibiotics, Antineoplastic↗
PubMed1977

[Anthracycline antibiotic, beromycin. The formation of complexes with DNA and the suppresion of nucleic acid biosynthesis].

Beromycin, an antitumor anthracycline antibiotic formed in vitro complexes with native and denaturated DNA and ribosomal RNA. Beromycin had a comparatively low constant of DNA binding and to a less extent increased the melting temperature and viscosity of DNA than the other anthracycline antibiotics. A peculiar property of beromycin was very slow binding with DNA, the complex formation was completed in 60 minutes. Beromycin had a selective inhibitory effect on synthesis of nucleic acids in bacterial and tumor cells. Beromycin inhibited synthesis of RNA in the DNA-dependent RNA-polymerase reaction when both the native and denaturated DNA were used as the template. A lower biological activity of beromycin as compared to the other anthracycline antibiotics, such as rubomycin or carminomycin may be explained by lower affinity of this antibiotic to DNA.

Animals↗
PubMed1977

[Study of the toxicity and antiblastoma activity of antibiotics echinomycin and 6270 in complexes with DNA].

Studies with the use of intact inbred albino mice showed that in intravenous administration the acute toxicity of antibiotic No. 6270 and echinomycin in complexes with DNA increased 3--4 times as compared to the toxicity of the same antibiotics used without the complex. Under the experimental conditions with 3-fold intravenous administration at 72-hour intervals in doses equivalent by their acute toxicity, the antitumor activity of the echinomycin complex with DNA against the solid form of lymphosarcoma L10-1 was approximately 4 times lower than the activity of the antibiotic used alone. Like echinomycin, antibiotic No. 6270 in complex with DNA used according to the same administration scheme in doses equivalent by their acute toxicity had a lower inhibitory effect on growth of lymphosarcoma L10-1 and sarcoma 180 as compared to its use alone.

Animals↗
PubMed1976

[Intensification of the bactericidal action of mitomycin C and of UV irradiation with some anthracycline antibiotics].

Anthracycline antibiotics, such as rubomycin C (rubomycin, daunomycin), rubomycin B, carminomycin and tavromycetin (cinerubin) significantly increased the bactericidal effect of ultraviolet radiation and mitomycin C with respect to mutant 19-8 of E. coli with increased permeability of the cell membrane. This may be accounted for inhibition of DNA reparation. Beromycin, an antibiotic of the same group had no such capacity. With respect to their activity the antibiotics were arranged as follows: rubomycin C, rubomycin B, carminomycin, tavromycetin.

Antibiotics, Antineoplastic↗