ABSTRACT
The effect of 8-oxo-2'-deoxyguanosine (8-oxo-dG) (8-hydroxydeoxyguanosine)--a DNA base damage product induced by oxygen radicals and irradiation on survival and mutagenesis in Escherichia coli strains C-600 and P-687 was investigated. Survival and mutagenesis curves, in dependence of 8-oxo-dG concentrations in the medium, ranging from 0.2 through 10 mM, were obtained. Bacterial survival at all 8-oxo-dG concentrations tested was shown to be no lesser than in the control. The mutagenic effect of 8-oxo-dG was tested by frequency of reversions in the absence of leucine and threonine. A non-linear dependence of mutagenesis on the concentration was observed. Linear increase in the amount of revertants took place at concentrations of 8-oxo-dG lower than 1 mM, and being kept constant at higher concentrations. Induction of SOS repair under the action of 8-oxo-dG in E. coli PQ37 strain was estimated according to alteration of activity of beta-galactosidase in the SOS chromotest. Weak induction of the SOS response was observed within the wide range of 8-oxo-dG concentration values, which points to a lack of genotoxicity and independence of mutagenesis on SOS repair.
Subject(s)
DNA Damage , Deoxyguanosine/analogs & derivatives , Escherichia coli/genetics , Mutagens/toxicity , Reactive Oxygen Species/toxicity , 8-Hydroxy-2'-Deoxyguanosine , Deoxyguanosine/toxicity , Escherichia coli/drug effects , Free Radicals , Gamma Rays , SOS Response, Genetics/genetics , beta-Galactosidase/metabolismABSTRACT
Gamma-irradiated serum albumin activated L-tyrosine oxidation to 3,4-dioxyphenyl alanine (DOPA) and forms adducts with DOPA oxidation products. These adducts are more resistant to proteolysis and have bactericidal and mutagenic capacity. A possible role of such adducts in a radiation damage to the organism is discussed.
Subject(s)
Serum Albumin, Bovine/radiation effects , Dihydroxyphenylalanine/metabolism , Drug Interactions , Gamma Rays , In Vitro Techniques , Oxidation-Reduction/radiation effects , Protein Binding/radiation effects , Serum Albumin, Bovine/metabolism , Solutions , Tyrosine/metabolismABSTRACT
In addition to the growth of low molecular weight quinoid radiotoxins the toxic effects of albumin were registered in rat plasma 4-24 h following gamma-irradiation. It is assumed that adducts of albumin with quinoid radiotoxins are formed and contribute to the development of radiation injury to critical organism tissues.
Subject(s)
Radiation Injuries, Experimental/blood , Toxins, Biological/blood , Animals , Blood Bactericidal Activity/radiation effects , Cobalt Radioisotopes , Gamma Rays , Male , Rats , Rats, Inbred Strains , Serum Albumin/metabolismABSTRACT
In experiments with model plant tumors (Kalanchoe-ti plasmid Agrobact. tumefaciens C-58D) it was shown that exposure of the recipient plant to low-level gamma-radiation of 2 Gy induced changes in cells that were not repaired over two months promoting tumoral transformations in them. Those changes were shown to persist in the offspring of the exposed somatic cells.
Subject(s)
Cell Transformation, Neoplastic/radiation effects , DNA Repair/radiation effects , Neoplasms, Radiation-Induced/genetics , Plant Tumors/etiology , Plant Tumors/genetics , Radiation GeneticsABSTRACT
Quinoid radiotoxins were found in the peripheral blood 3-4 h following gamma-irradiation of dogs with doses of 5.76 Gy. The authors developed a simple method of isolation and purification of quinoid radiotoxins and specified their physicochemical and biological characteristics.