Ascorbate-glutathione cycle in wheat and rice seedlings under anoxia and subsequent reaeration.

The most important part of the plant antioxidant system is the ascorbate-glutathione cycle (AGC), the activity of which is observed upon exposure to a range of stressors, including lack of O2, and oxidative stress occurring immediately after the restoration of oxygen access, hereafter termed reaeration or post-anoxia. The operation of the AGC (enzymes and low-molecular components) in wheat (Triticum aestivum, cv. Leningradka, non-resistant to hypoxia) and rice (Oryza sativa, cv. Liman, resistant) seedlings after 24 h anoxia and 1 h or 24 h reaeration was studied. Significant accumulation of oxidized forms of ascorbate and glutathione was revealed in the non-resistant plant (wheat) after 24 h of anoxia and reaeration, indicating the development of oxidative stress. In the resistant plant (rice), reduced forms of these antioxidants prevailed both in normoxia and under stress, which may indicate their intensive reduction. In wheat, the activities of ascorbate peroxidase and dehydroascorbate reductase in shoots, and monodehydroascorbate reductase and glutathione reductase in roots decreased under anoxia and reaeration. The activity of antioxidant enzymes was maintained in rice under lack of oxygen (ascorbate peroxidase, glutathione reductase) and increased during post-anoxia (AGC reductases). Anoxia stimulated accumulation of mRNA of the organellar ascorbate peroxidase genes OsAPX3, OsAPX5 in shoots, and OsAPX3-5 and OsAPX7 in roots. At post-anoxia, the contribution of the OsAPX1 and OsAPX2 genes encoding the cytosolic forms of the enzyme increased in the whole plant, and so did that of the OsAPX8 gene for the plastid form of the enzyme. The accumulation of mRNA of the genes OsMDAR2 and OsMDAR4 encoding peroxisomal and cytosolic monodehydroascorbate reductase as well as the OsGR2 and OsGR3 for cytosolic and organellar glutathione reductase was activated during reaeration in shoots and roots. In most cases, O2 deficiency activated the genes encoding the peroxisomal, plastid, and mitochondrial forms of the enzymes, and upon reaeration, an enhanced activity of the genes encoding the cytoplasmic forms was observed. Taken together, the inactivation of AGC enzymes was revealed in wheat seedlings during anoxia and subsequent reaeration, which disrupted the effective operation of the cycle and triggered the accumulation of oxidized forms of ascorbate and glutathione. In rice, anoxia led to the maintenance of the activity of AGC enzymes, and reaeration stimulated it, including at the level of gene expression, which ensured the effective operation of AGC.

[Stimulation of homo- and heterologic T-cell immunological memory in volunteers inoculated with live influenza A (H5N2) reassortant vaccine].

The study deals with the ability of live attenuated reassortant influenza vaccine (LAIV) A (H5N2) to stimulate a CD4+ and CD8+ immunological memory T cell-mediated immune response in volunteers. These data were compared with the quantitative characteristics of a humoral immune response. A two-dose regimen of intranasal vaccination of avian influenza naïve people with A (H5N2) LAIV induced the production of circulating CD4+ and CD8+ memory cells specific to both A (H5N2) and seasonal A (H1N1) influenza strains. Some of the volunteers were not absolutely A (H5N2) influenza virus naïve since they had been found to have this virus-specific cross-reactive immunological memory T-cells in the prevaccination period. The content (%) of these cells varied significantly within the group. The quantitative values of postvaccination CD4+ and CD8+ memory cell accumulation were inversely related to their prevaccination level.

[The development of method of intravenous laser irradiation of blood with green laser in patients with hyperlipidemia].

The impact of intravenous laser irradiation of blood with green laser in patients with hyperlipidemia was investigated. The blood of patients was chosen as sample for analysis. The patients were divided in two groups: patients with atherosclerosis of various localization and patients with atherosclerosis associated with diabetes mellitus. The effectiveness of laser impact was evaluated according the blood biochemical indicators. The levels of crude cholesterol, triglycerides, low and very low density lipoproteins, apoproteins A and B, highly sensitive C-reactive protein, atherogenity indicator, glucose content, uric acid content were determined befor and after 1, 3 and 6 months after impact. The study results indicate the occurrence of hypolipedemic and hypoglycemic effects.

[Estimation of human and animal immunological memory by testing the trogocytosis of virus-specific T lymphocytes].

This study is the first attempt to evaluate the immunogenicity of Russian live attenuated influenza reassortant influenza vaccine (LAIV), by using a modified T-cell recognition of antigen presenting cells by protein capture (TRAP) method. Single vaccination of 18-20-year-old volunteers with LAIV causes an increase in the peripheral blood levels of virus-specific memory CD4+ T lymphocytes. Some (40-60%) LAIV-vaccination volunteers respond to immunization by showing a significant elevation in the peripheral blood level of memory CD4+ T cells without a systemic humoral immune response recorded in the passive hemagglutination test. Vaccination of mice with live attenuated A (H1N1) influenza reassortant virus stimulates the production of memory CD8+CD44hi T lymphocytes in the nasal-associated lymphoid tissue, the entry of infection, so does influenza infection. Vaccination with inactivated A (H1N1) influenza virus practically fails to induce these cells. A (H1N1) influenza virus-specific CD8+CD44hi T lymphocytes remain within at least 2 months (observation time). The authors' modified TRAP may be used to evaluate virus-specific immunological T-cell memory after vaccination.

Memory T-cell immune response in healthy young adults vaccinated with live attenuated influenza A (H5N2) vaccine.

Cellular immune responses of both CD4 and CD8 memory/effector T cells were evaluated in healthy young adults who received two doses of live attenuated influenza A (H5N2) vaccine. The vaccine was developed by reassortment of nonpathogenic avian A/Duck/Potsdam/1402-6/68 (H5N2) and cold-adapted A/Leningrad/134/17/57 (H2N2) viruses. T-cell responses were measured by standard methods of intracellular cytokine staining of gamma interferon (IFN-γ)-producing cells and a novel T-cell recognition of antigen-presenting cells by protein capture (TRAP) assay based on the trogocytosis phenomenon, namely, plasma membrane exchange between interacting immune cells. TRAP enables the detection of activated trogocytosis-positive T cells after virus stimulation. We showed that two doses of live attenuated influenza A (H5N2) vaccine promoted both CD4 and CD8 T-memory-cell responses in peripheral blood of healthy young subjects in the clinical study. Significant differences in geometric mean titers (GMTs) of influenza A (H5N2)-specific IFN-γ(+) cells were observed at day 42 following the second vaccination, while peak levels of trogocytosis(+) T cells were detected earlier, on the 21st day after the second vaccination. The inverse correlation of baseline levels compared to postvaccine fold changes in GMTs of influenza-specific CD4 and CD8 T cells demonstrated that baseline levels of these specific cells could be considered a predictive factor of vaccine immunogenicity.

Anoxic stress leads to hydrogen peroxide formation in plant cells.

Hydrogen peroxide (H2O2) was detected cytochemically in plant tissues during anoxia and re-oxygenation by transmission electron microscopy using its reaction with cerium chloride to produce electron dense precipitates of cerium perhydroxides. Anoxia-tolerant yellow flag iris (Iris pseudacorus) and rice (Oryza sativa), and anoxia-intolerant wheat (Triticum aestivum) and garden iris (Iris germanica) were used in the experiments. In all plants tested, anoxia and re-oxygenation increased H2O2 in plasma membranes and the apoplast. In the anoxia-tolerant species the response was delayed in time, and in highly tolerant I. pseudacorus plasma membrane associated H2O2 was detected only after 45 d of oxygen deprivation. Quantification of cerium precipitates showed a statistically significant increase in the amount of H2O2 caused by anoxia in wheat root meristematic tissue, but not in the anoxia-tolerant I. pseudacorus rhizome parenchyma. Formation of H2O2 under anoxia is considered mainly an enzymatic process (confirmed by an enzyme inhibition analysis) and is due to the trace amount of dissolved oxygen (below 10(-5) M) present in the experimental system. The data suggest oxidative stress is an integral part of oxygen deprivation stress, and emphasize the importance of the apoplast and plasma membrane in the development of the anoxic stress response.

[Free radical lipid peroxidation in clean-up workers from the Chernobyl nuclear reactor accident depending on working conditions in the area of radioactive contamination]. / Sostoianie svobodnoradikal'nogo okisleniia lipidov u likvidatorov avarii na Chernobyl'skoi AES v zavisimosti ot uslovii raboty v zone radioaktivnogo zagriazneniia.

Plasma lipids and antioxidant defense factors were examined 5-6 years after the exposure in 49 subjects who had taken part in decontamination of the territories after the Chernobyl accident against those in non-exposed donors. Elevated levels of heptane-soluble lipoperoxides and of dienketones were registered, though malonic dialdehyde changed little. The above parameters deviated from the control level more in subjects exposed to higher ecological risk. In this group of examinees the antioxidant activity failed to neutralize lipoperoxide excess under low activity of plasma catalase. Antioxidant drugs are recommended to manage disorders of lipoperoxide homeostasis in subjects exposed to radiation as a result of Chernobyl accident.