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Biomedical subjects

I A Egorov

Publications and source records attributed to I A Egorov.

At least 19 recordsLinked to original sources
PubMed1989

[Induction of SOS function in Escherichia coli after exposure to various types of chemical mutagens].

On the basis of the SOS-chromotest which was developed by the authors earlier, the minimum time required for expression of the SOS-response is shown to be 15 min, the maximum being recorded 2 h later. An assay of induction of the SOS-response to the mutagens which act on DNA via various mechanisms (e. g., UV-irradiation, mitomycin C, nalidixic acid, nitroso-methylurea and acridine orange) revealed that all the mutagens under study caused induction of the SOS-response. Analysis of efficiency of SOS induction under the action of a mixture of formaldehyde with various amino acids has shown that arginine, asparagine and, especially, cysteine decrease the level of the SOS-response induction. This fact suggests an opportunity for using the SOS-chromotest not only to identify the mutagens and cancerogens, but also to screen the agents for their antimutagenic activity. The study of the SOS-response in the cells which are deficient in genes for repair and recombination has shown that induction is significantly suppressed in the mutants recA, lexA and recF; it is not modified in sbcB mutants and is significantly increased in the mutant lines recBC, uvrB and, particularly, in the double mutant recBCsbcB.

DNA Repair↗
PubMed1989

[Cloning the genetic determinant of alpha-hemolysin and obtaining a series of insertional mutations in this determinant by the transposon Tn1000].

Functionally active genetic determinant of alpha-hemolysin was cloned. Hemolytic plasmid pHly195 was used as a donor of the determinant and pBR322 plasmid served as recipient. Cloning was done with a help of HindIII restriction endonuclease. The recombinant plasmid obtained represents pBR322 plasmid with the built-in fragment of 7.4 kb containing genes of functionally active determinant of alpha-hemolysin. Restriction map was constructed using HindIII, EcoRI, BamHI and SalI restriction endonucleases. Insertional mutagenesis was carried out with the help of the Tn1000 transposon. Plasmid DNAs were isolated from insertional mutants of Hly- phenotype and treated with EcoRI, SalI and BamHI. On the basis of the sizes of restriction fragments of the mutant plasmid DNAs localization and orientation of insertions of Tn1000 into the cloned determinant of alpha-hemolysin were determined.

Bacterial Proteins↗
PubMed1979

Metalloporphyrins and molecular complexes of amino acids with porphyrins in juvenile volcanic ash.

In samples of juvenile ash of the volcano Tjatja, USSR (that erupted in 1973) metalloporphyrins were found. With respect to the fluorescence spectra free bases of the compounds were close to the pigments that formed in abiogenic synthesis experiments (predominance of long-wave length fluorescence band). The pigments detected occurred in the ash as molecular complexes with amino acids which seem to be a abiogenic origin. These findings are of interest in terms of exploration of the processes of chemical evolution and emergence of life on the Earth.

Amino Acids↗
PubMed1977

Porphyrins and phycobilins in Precambrian rocks.

Samples of Precambrian rocks (1.7-2.6 billion years, U.S.S.R.) contain metalloporphyrins and linear tetrapyrrole pigment similar to phycobilin 655 from modern blue-green algae Microystis (according to data of phosphorescence spectroscopy). The detection of ancient phycobilin makes it possible to relate the data on pigment paleobiochemistry with the evolution of photosynthetic system.

Geological Phenomena↗
PubMedDate not supplied

[Formation of alcohols during sucrose heating with amino acids].

The formation of alcohols during sucrose heating with amino acids was investigated. The sucrose heating to 180-190 degrees C resulted in the formation of methanol and ethanol and its heating with alanine--propanol and isobutanol. The sucrose heating with phenylalanine led to the formation of beta-phenylethanol as well. Alcohols were identified as benzoates by paper chromatography. They were also identified by infrared spectra.

1-Propanol↗
PubMedDate not supplied

[Decrease in the radiation effect in the lymphoid organs of animals adapting to altitude].

Adaptation to altitude hypoxia exerts a positive effect on the cell density of lymph organs of gamma-irradiated animals. It also reduces radiation degradation of DNA, its availability to DNase in the nuclear chromatin and disorders in the activity of DNA polymerases. The role of inhibition of radiation-induced degradation of chromatin DNA in the protective effect of altitude adaptation on the cell density of lymph organs is discussed.

Adaptation, Physiological↗