Effect of ionizing radiation on the lipid composition of aminoacyl-tRNA-synthetase complexes

The effect of X-radiation (0.21 C/kg) on a lipid component of aminoacyl-tRNA-synthetase complexes from rat liver (for instance, phospholipids, neutral lipids, and prostaglandins) has been studied. The content of prostaglandins and lysophosphatidyl choline increases and that of phospholipids and neutral lipids decreases 60 min after irradiation. In 24 h, the content of prostaglandins, fatty acids, cholesterol, and phosphatidyl ethanolamine approaches the control level.     

Effect of laser radiation and combined ionizing and laser radiation on the cell-division time of bacteria

Irradiation of E. coli K-12 cells of the wild-type AB 1157 strain with helium-neon continuous laser radiation leads to a temporary delay in their division. The delay was found to be the same in cells exposed to ionizing radiation alone and in cells exposed to a combination of ionizing and laser radiation.     

Effect of ionizing radiation on the lipid fatty acid composition of the plasma membranes of liver cells

Changes in the fatty acid composition of total lipids and individual phospholipids of liver cell plasma membranes of intact and exposed (7.65 Gy) rats have been studied. The authors discuss the relationship between the degree of lipid oxidation and other lipid characteristics of the studied membrane after exposure to ionizing radiation.     

Glutathione transferase in bacteria: subunit composition and antigenic characterization

The presence of glutathione transferase (GST; EC 2.5.1.18) in Escherichia coli ATCC 25922, E. coli ATCC 25422, Proteus vulgaris ATCC 8427, Pseudomonas aeruginosa ATCC 27853, Klebsiella oxytoca CIP 666, K. oxytoca AF 101, Enterobacter cloacae CIP 6085, Serratia marcescens CIP 6755, and Proteus mirabilis AF 2924 was investigated. Using 1-chloro-2,4-dinitrobenzene as substrate, GST activity was found in the glutathione-(GSH-)affinity-purified fraction of all strains tested. SDS-PAGE analysis of GSH-affinity-purified enzyme indicated that the GSTs of all these bacteria are dimers of two identical subunits of Mr about 22,500. Rabbit antiserum directed against the major isoenzyme present in Proteus mirabilis AF 2924, Pm-GST-6.0, was used to investigate the antigenic properties of bacterial GSTs. Western blot analysis indicated that a GST antigenically identical to Pm-GST-6.0 is present in Enterobacter cloacae CIP 6085, Escherichia coli ATCC 25422 and Proteus vulgaris ATCC 8427, but absent in Escherichia coli ATCC 25922, Klebsiella oxytoca CIP 666, K. oxytoca AF 101 and Serratia marcescens CIP 6755. The presence of Pm-GST-6.0, but not mammalian GST, increased the MIC values of amikacin, ampicillin, cefotaxime, cephalothin and nalidixic acid for E. coli ATCC 25922. It is suggested that bacterial GST may represent a defense against the effects of antibiotics.     

Effect of ionizing radiation on the aggressive behavior of mice

Changes in the aggressiveness of mice were studied after exposure thereof to 5, 10, 30, 60 and 100 Gy radiation. With doses of 5, 10 and 30 Gy no stable effect on the aggressive behaviour of mice was observed, while doses of 60 and 100 Gy suppressed it drastically. Stress at the time of exposure can enhance the antiaggressive effect of radiation.     

Effect of hyperthermia and ionizing radiation on the erythrocyte membrane

Spin-label studies of the effects of hyperthermia on the erythrocyte membrane revealed a decrease in the fluidity of lipids and changes in the state of membrane proteins. The rate of haemolysis in iso-osmotic glycerol solution was increased. Changes of most of the parameters studied when plotted in Arrhenius coordinates revealed a discontinuity (critical hyperthermic transition in the membrane) between 46 and 50 degrees C. Studies of the combined action of ionizing radiation (100 Gy) and hyperthermia (43 degrees C) showed the same direction of changes for (Na-K-Mg)-ATPase activity and spectra of membrane-bound maleimide spin label for both agents, but the additivity of changes depended on the parameter studied.