Mechanism of thymocyte death in exposure to ultrahigh doses of gamma radiation

A comparative study was made of the morphological and biochemical indices of rat thymus cells after gamma-irradiation with doses of 4-10 Gy (median), 20 Gy (high), and 200-400 Gy (superhigh). It was shown that 4 h after irradiation with superhigh doses the yield of polydeoxynucleotides (PDN) was twice as low as that observed after doses of 4-10 Gy. 24 h after irradiation the amount of the extracted PDN in thymocytes exposed to superhigh doses was markedly larger than that after 4 hours. After all doses applied chromatin degradation occurred at the internucleosome sites in a strict order, the activity of acid and alkaline nucleases being unchanged. A large number of cells have normal nuclear structure 4 h after irradiation (200-400 Gy), as was demonstrated by the electron microscopy data, while in 24 h no intact cells were virtually found in the thymus which correlated with the changes in the PDN yield. The mechanisms of the lymphoid cell death under the effect of different radiation doses are discussed.     

Development of diagnostic methods based on a core antigen of hepatitis B, obtained by methods of genetic engineering

The possibility of using recombinant HBcAg, synthesized in Escherichia coli, for diagnostic purposes has been studied. The antigen can be used in highly sensitive immunological assays for the detection of IgG and IgM antibodies to HBcAg.     

Long-term potentiation in the neurons of the edible snail

A brief high-frequency stimulation of the anal nerve of the isolated nerve ring of snail Helix induced a pronounced increase in the amplitude of EPSPs, evoked in identified neurons of left parietal and visceral ganglions by low frequency (once in 5 min) stimulation of the same nerve. The amplitude of EPSP returned to the control level 30-120 min after tetanization. We called this effect long-term potentiation. A brief application of serotonin (10 microM) in the majority of neurons also induced lasting either 15-30 min or more than 2 hours facilitation of EPSP, evoked by anal nerve stimulation. Intracellular cAMP injections, being without effect on EPSP amplitude in many neurons, in certain neurons caused an increase in EPSP amplitude, lasting up to 30 min. It is suggested that the 3 factors shown to increase synaptic efficiency in molluscan neurons may have common mechanisms of action.     

Antioxidant and signaling functions of the plastoquinone pool in higher plants

The review covers data representing the plastoquinone pool as the component integrated in plant antioxidant defense and plant signaling. The main goal of the review is to discuss the evidence describing the plastoquinone‐involved biochemical reactions, which are incorporated in maintaining the sustainability of higher plants to stress conditions. In this context, the analysis of the reactions of various redox forms of plastoquinone with oxygen species is presented. The review describes how these reactions can constitute both the antioxidant and signaling functions of the pool. Special attention is paid to the reaction of superoxide anion radicals with plastohydroquinone molecules, producing hydrogen peroxide as signal molecules. Attention is also given to the processes affecting the redox state of the plastoquinone pool because the redox state of the pool is of special importance for antioxidant defense and signaling.     

Role of Mucin 2 Glycoprotein and L-fucose in Interaction of Immunity and Microbiome within the Experimental Model of Inflammatory Bowel Disease

Biochemistry (Moscow) - Many factors underlie the development of inflammatory bowel disease (IBD) in humans. In particular, imbalance of microbiota and thinning of the mucosal layer in the large...     

Inhibitor factors in the serum of patients with the AIDS-related complex

The data on the presence of factors blocking the reaction of E-rosette formation and leukocyte chemotaxis in the blood sera of patients with AIDS-related complex (ARC) and HIV-positive donors are presented. Most frequently the blocking of E-rosette formation coincided with the presence of a inhibiting effect on the migration capacity of leukocytes. This blocking activity was not linked with the presence of C-reactive protein in the circulation stream. The treatment of ARC patients with plasmapheresis and/or travolol was accompanied either by the disappearance of blocking activity or by the appearance of activity stimulating E-rosette formation.