Modifying effect of water-soluble analogs of quinoid radiotoxins on hematopoiesis in gamma-irradiated mice

It was established that quinoid products of tyrosine oxidation, analogues of natural radiotoxins, when used in the studied doses decreased the radiosensitivity of spleen stem cells and enhanced the restoration of bone marrow cellularity of mice exposed to sublethal gamma-radiation doses.     

Effect of extremely low frequency magnetic fields on time-related pattern of metabolism of thiol groups and products of lipid peroxidation in the brain of mice]

The influence of extremely low-frequency magnetic fields on lipid peroxidation products and total thiol groups in the brain of mongrel mice has been investigated. Certain changes in time organization and interrelation of the studied processes under the effect of the magnetic field depending on frequency are shown.     

Quinoid radiotoxins in the blood of gamma-irradiated dogs

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.     

The role of fat-soluble vitamins A and E in preventing the biological effects of ionizing radiation in rat tissues]

The lipid peroxidation level and the antioxidant system status have been studied by the amount of alpha-tocopherol and the antioxidant activity of homogenates in the brain, liver, heart and somatic muscle of rats given Vitamins A and E, as physiological additives, before and after gamma-irradiation. It has been shown that a new dynamic balance between the parameters under study is rapidly set up after irradiation, which represents a mechanism of rapid adaptation. The radioprotective effect of alpha-tocopherol is more pronounced than that of Vitamin A (particularly in the brain). In most cases, Vitamin A produces, upon irradiation, an unfavourable effect on antioxidative homeostasis.     

The power and limitations of influenza virus hemagglutinin assays

Influenza virus hemagglutinins (HAs) are surface proteins that bind to sialic acid residues at the host cell surface and ensure further virus internalization. Development of methods for the inhibition of these processes drives progress in the design of new antiviral drugs. The state of the isolated HA (i.e. combining tertiary structure and extent of oligomerization) is defined by multiple factors, like the HA source and purification method, posttranslational modifications, pH, etc. The HA state affects HA functional activity and significantly impacts the results of numerous HA assays. In this review, we analyze the power and limitations of currently used HA assays regarding the state of HA.     

Production of Heterotrophic Bacterioplankton in a Large Meso-Eutrophic Reservoir: The Importance of Extracellular Organic Carbon Released by Phytoplankton

The spatial distribution and seasonal dynamics of heterotrophic bacterioplankton production have been studied and the value of autochthonous sources of substrates for bacteria has been evaluated in the pelagic zone of the meso-eutrophic Rybinsk Reservoir (the Upper Volga). During the vegetation period, the bacterial production ranges from 32 to 1352 (on average 444 ± 44) mg C/(m² × day). The total input of organic carbon from the processes of extracellular production of phytoplankton, viral lysis of prokaryotic cells, and feeding of protists provides 9–64% (32 ± 3% on average) of the daily carbon demand for heterotrophic bacterioplankton.     

Mass spectrometry identification of cytochrome P450 2B4 interaction sites for NADPH: Cytochrome P450 reductase

The interaction sites for protein partners, cytochrome P450 2B4 (d-2B4) and NADPH: cytochrome P450 reductase (d-Fp), have been identified. These proteins form complexes during their functioning. Nonspecific covalent cross-linking of the d-2B4 complexes with d-Fp in the Emulgen 913 monomerized system was achieved by 4,4′- dithiobis-phenyl azide. Covalently cross-linked peptides of this complex were identified by ESI-MS/MS. Several binding sites have been identified for these proteins. Based on these sites a model for intermolecular interaction between these proteins has been proposed. This model includes 5 contact sites on d-2B4 for d-Fp (stabilized by the cross-linker); these include the following pairs of corresponding peptides of d-2B4 and d-Fp: 1) d-2B4_324–336 and d-Fp_570–585; 2) d-2B4_423–433 and d-Fp_102–109; 3) d-2B4_327–336 and d Fp_452–464; 4) d-2B4_192–197 and d-Fp_456–464; 5) d-2B4_134–139 and d-Fp_406–425. In the two last cases d-Fp peptides are located in the interdomain cleft and stabilize the protein-protein complex via the cross-linker and so the d 2B4/d-Fp complex formation by these sites may involve amino acid residues of the peptides d-Fp_456–464 and d-Fp_406–425, which surround the interdomain cleft.