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91.
Decay of 89Sr incorporated in yeast cells produces a pronounced inactivating effect. The transmutation mainly contributes (about 80%) to cell inactivation. Haploid cells are more sensitive to 89Sr disintegration than diploid and tetraploid ones. A radiosensitive mutant XRS2, that is particularly sensitive to the transmutation effect of radionuclides, has proved to be sensitive to 89Sr transmutation as well. At the same time, another radiosensitive mutant, rad 54, does not virtually differ from the wild-type strain by its sensitivity to 89Sr decay. 相似文献
92.
A S Taisova N P Korolev N S Griaznova E Ia Zinchenko Z I Lesovaia 《Antibiotiki i khimioterapii͡a》1989,34(7):504-510
Interaction of cephalosporin antibiotics with flat bilayer lipid membranes (BLM) composed of vegetative or bacterial phospholipids was studied with respect to their effect on electroconductivity, capacity for binding to the bilayers and capacity for transmembrane transfer through the bilayers. By their effect on conductivity, the investigated cephalosporins could be divided into three groups: those having no effect on conductivity at the maximum concentrations (up to 1 mg/ml) i.e. cefoperazone, cefotaxime and ceftizoxime, those having an effect on conductivity at concentrations of 0.2 to 0.5 mg/ml i.e. cephalexin and cephalothin and those having a significant effect on conductivity at concentrations of 10 to 60 micrograms/ml i.e. N-acyl derivative of 7-ACA (substance 64) and 7-ACA derivative (substance 71). The cephalosporins had a capacity for binding to the bilayers and for incorporation into the bilayers. They penetrated to some extent through the bilayers composed of either vegetable or bacterial phospholipids. The lower rate of penetration through the BLM as compared to that of penicillins must be due to lower hydrophobicity of the cephalosporin molecules as compared to that of penicillins. 相似文献
93.
94.
E. L. Ivanov S. V. Kovaltzova G. V. Kassinova L. M. Gracheva V. G. Korolev I. A. Zakharov 《Mutation research》1986,160(3):207-214
We have studied the molecular nature of ade2 mutations induced by UV light and bifunctional acridine-mustard (BAM) in wild-type (RAD) and in excision-deficient (rad2) strains of the yeast, Saccharomyces cerevisiae. In the RAD strain, UV causes 45% GC → AT transitions among all mutations; in the rad2 strain this value is 77%. BAM was shown to be highly specific for frameshift mutagenesis: 60% frameshifts in the RAD strain, and as many as 84% frameshifts in the rad2 strain were induced. Therefore, the rad2 mutation affects the specificity of UV- and BAM-induced mutagenesis in yeast. Experimental data agree with the view that the majority of mutations in the RAD strain are induced by a prereplicative mechanism, whereas mutations in the RAD strain are induced by a prereplicative mechanism, whereas mutations in the rad2 strain are predominantly postreplicative events. Our results also suggest that: (1) cytosine-containing photoproducts are the substances responsible for major premutational damage to DNA; (2) a fraction of the mutations may arise in the course of excision repair of UV photoproducts. 相似文献
95.
96.
K. A. Zaitseva V. I. Korolev 《Journal of Evolutionary Biochemistry and Physiology》2000,36(2):183-189
The performed study of peculiarities of echo-detection of moving underwater targets by the Black Sea bottlenosed dolphins,Tursiops truncatus, suggests that the biosonar can purposefully change the structure of its probe signal, depending on the problem to be solved.
It was shown experimentally for the first time that the animal emits the two-pulse probe signal to measure the constant velocity,
while the three-pulse one, to measure acceleration. This provides an essential advantage over the single pulse, as it becomes
possible to measure simultaneously parameters of the movement and distance. 相似文献
97.
98.
I I Ivanov N P Korolev B K Semin V Lap Z Wunderlich 《Nauchnye doklady vysshe? shkoly. Biologicheskie nauki》1986,(5):35-40
The effect of antioxidants alpha-tocopherol and ionol on membranes of human red cells and bilayer lipid membrane (BLM) from azolektin has been studied. Ionol at concentration 4-10 mM induces the hemolysis of erythrocytes, the cells form changes are observed at concentration 2 mM alpha-tocopherol doesn't show the hemolytic properties at concentration 23 mM. The ionol concentration 1 mM doesn't change the form of the cells, but influence the passive electric parameters: the capacity (Cs) of erythrocytic membrane increases and the intracellular conductance (chi i) decreases. Tocopherol (3 mM) induces the decrease both Cs and chi i. The fast increase of membrane conductance is almost immediately registered on one side of BLM at addition of ionol (0,2-0,4 g/ml). Phosphatidylionol synthesized from ionol and contining the acyl chains C15H31 and C17H35 doesn't influence the electrical properties of BLM. 相似文献
99.
Anna N. Tevyashova Elena N. Bychkova Alexander M. Korolev Elena B. Isakova Elena P. Mirchink Ilya A. Osterman Réka Erdei Zsolt Szücs Gyula Batta 《Bioorganic & medicinal chemistry letters》2019,29(2):276-280
One of the promising directions of the combined approach is the design of dual-acting antibiotics – heterodimeric structures on the basis of antimicrobial agents of different classes. In this study a novel series of azithromycin-glycopeptide conjugates were designed and synthesized. The structures of the obtained compounds were confirmed using NMR spectroscopy and mass spectrometry data including MS/MS analysis. All novel hybrid antibiotics were found to be either as active as azithromycin and vancomycin against Gram-positive bacterial strains or have superior activity in comparison with their parent antibiotics. One compound, eremomycin-azithromycin conjugate 16, demonstrated moderate activity against Enterococcus faecium and Enterococcus faecalis strains resistant to vancomycin, and equal to vancomycin’s activity for the treatment of mice with Staphylococcus aureus sepsis. 相似文献
100.
Aleksandrov V. V. Volkov G. S. Grabovski E. V. Gritsuk A. N. Volobuev I. V. Kalinin Yu. G. Korolev V. D. Laukhin Ya. N. Medovshchikov S. F. Mitrofanov K. N. Oleinik G. M. Pimenov V. G. Smirnova E. A. Frolov I. N. 《Plasma Physics Reports》2019,45(9):805-820
Plasma Physics Reports - The implosion of combined loads consisting of an outer wire (fiber) array and inner cylindrical target was studied experimentally at the Angara-5-1 facility (3.5 MA, 100... 相似文献