Military toxicology teaching specialists of higher education military institution, in line with special professional development programs, have considered issues of emerging discipline allowing for the forms of knowledge transmission, as part of the joint scientific research and organized postgraduate education courses. Paper studies the organizational approaches to the lecture course design in terms of higher professional education. Forms of military toxicology teaching were systematized using simulants of toxic substances, fundamental knowledge of the critical processes’ physiology, their pharmacological and pharmaceutical modifications, molecular docking in risk evaluation of new toxicants creating.

A highly effective producer strain Escherichia coli C3030/pET23d + - Ec HGPRT, allowing production of recombinant hypoxanthine‒guanine phosphoribosyltransferase from E. coli ( Ec HGPRT) in a soluble form, has been created. A method for isolating and purifying the recombinant protein has been developed. The specific activity against the natural substrate and pyrazine-2-carboxamide derivatives has been determined. Crystals of the Ec HGPRT complexes with 3-hydroxypyrazine-2-carboxamide (T-1105) and 6-fluoro-3-hydroxypyrazine-2-carboxamide (T-705), suitable for X-ray diffraction analysis, have been grown by capillary counter diffusion. X-ray diffraction sets with a resolution of up to 2.4 and 2.5 Å have been collected at the ESRF synchrotron (France, station ID23-1) at a temperature of 100 K. The crystals belong to the sp. gr. P 3(1)21; the independent part of the cell contains two enzyme molecules.

The essence of the preconditioning effect is the activation of urgent defense mechanisms of adaptation as a result of a short episode of weak, non-damaging hypoxic or ischemic exposure, which contributes to an increase in the tolerance of the subsequent delayed, more severe exposure to hypoxia or ischemia. Aim of the study was to assess the literature data on the possibility of using the method of remote ischemic preconditioning (RIP) as a non-pharmacological method for correcting physical performance. Material and methods. In the Scopus, PubMed and eLibrary databases, a selection and analysis of modern literature sources devoted to the issues of increasing human performance, especially by nonpharmacological methods, as well as the use of distant preconditioning to increase physical performance and the mechanisms for implementing this effect, were carried out. Results. Since the discovery of the phenomenon until now, researchers have considered RIP, mainly as a way to protect organs and cells from ischemic damage in clinical practice. The article presents the literature data on the use of RIP as a non-drug method for improving physical performance with single and course use cases. In addition, the article focuses on the mobilization of the body’s own resources through the mechanisms of adaptation to hypoxia developing during RIP. Conclusions. Among the non-pharmacological methods of increasing physical performance, one of the most promising, in our opinion, is RIP that mobilizes the body’s own resources through the mechanisms of adaptation to hypoxia. The advantage of the method based on short-term cessation of blood circulation in the lower extremities and subsequent reperfusion does not apply to the ways prohibited in sports, does not require the use of drugs and the availability of special equipment, signifcant costs of economic and organizational resources.

To this date, the issue of methods development for evaluation of human physical tolerance to exercises in the mountains remains relevant. In this regard, the authors consider the current methodological approaches to the assessment of hypoxia tolerance: methods based on recording of changes in genetic and biochemical hypoxia markers; functional tests (Stange’s, Serkin’s, Rosenthal’s tests, etc.), accompanied by short-term acute hypoxia, with and without respect to anthropometric data; methods for evaluation of hypoxia tolerance based on breathing the oxygen-reduced air without performing physical exercise (anoxic hypoxia, hypobaric hypoxia) and with it (anoxic hypoxia and “load” hypoxia). Based on the results of the analysis of literature data, the main positive and negative aspects of these methods are noted, and the need to develop a methodology that includes a full assessment of the response of the cardiorespiratory system under hypoxic conditions using cardiopulmonary exercise testing is shown.

1,4-Pyrazine-3-carboxamide-based antiviral compounds have been under intensive study for the last 20 years. One of these compounds, favipiravir (6-fluoro-3-hydroxypyrazine-2-carboxamide, T-705), is approved for use against the influenza infection in a number of countries. Now, favipiravir is being actively used against COVID-19. This review describes the in vivo metabolism of favipiravir, the mechanism of its antiviral activity, clinical findings, toxic properties, and the chemical synthesis routes for its production. We provide data on the synthesis and antiviral activity of structural analogs of favipiravir, including nucleosides and nucleotides based on them.

Research into cardiorespiratory responses to prolonged hypoxia (more than 60 minutes) is of particular interest in terms of elucidating adaptive mechanisms under the conditions of oxygen deficiency. Aim: to identify the parameters of the cardiorespiratory system under relative rest most sensitive to hypoxia and to determine the most optimal time interval for a hypoxic test. Experiments were carried out in a normobaric hypoxic complex, in which hypoxic respiratory gas conditions were created corresponding to the partial oxygen pressure at altitudes of 3500 and 4500 m. Cardiorespiratory responses were evaluated using a MetaLyzer 3B ergospirometric system (Cortex, Germany). Indicators sensitive to moderate normobaric hypoxia under relative rest include hemoglobin oxygen saturation (the most sensitive indicator), oxygen and carbon dioxide ventilation efficiency (VE/VO 2 and VE/VCO 2 ), respiratory rate and respiratory coefficient (VCO 2 / VO 2 ). A significant change in the indicators of the cardiorespiratory system at an altitude of 4500 m was noted within 5 minutes following hypoxic exposure; therefore, normobaric hypoxic tests should be carried out at this height under the hypoxic exposure of 30 minutes.

Research into cardiorespiratory responses to prolonged hypoxia (more than 60 minutes) is of particular interest in terms of elucidating adaptive mechanisms under the conditions of oxygen deficiency. Aim: to identify the parameters of the cardiorespiratory system under relative rest most sensitive to hypoxia and to determine the most optimal time interval for a hypoxic test. Experiments were carried out in a normobaric hypoxic complex, in which hypoxic respiratory gas conditions were created corresponding to the partial oxygen pressure at altitudes of 3500 and 4500 m. Cardiorespiratory responses were evaluated using a MetaLyzer 3B ergospirometric system (Cortex, Germany). Indicators sensitive to moderate normobaric hypoxia under relative rest include hemoglobin oxygen saturation (the most sensitive indicator), oxygen and carbon dioxide ventilation efficiency (VE/VO 2 and VE/VCO 2 ), respiratory rate and respiratory coefficient (VCO 2 / VO 2 ). A significant change in the indicators of the cardiorespiratory system at an altitude of 4500 m was noted within 5 minutes following hypoxic exposure; therefore, normobaric hypoxic tests should be carried out at this height under the hypoxic exposure of 30 minutes.

Previous publications reported the use of remote ischemic preconditioning (rIPC) as a non-drug method for increasing physical performance. However, the reported data are of a contradictory nature. Aim: to evaluate the potential of rIPC for increasing the physical performance of laboratory animals. The study was performed on 72 white outbred male rats. An assessment of the physical performance was carried out using a modified Porsolt test. The hind limbs of non-anesthetized animals were subjected to preconditioning. The results of a single and course (during 5 days) application of rIPC was evaluated. A single use of rIPC increased the average swimming time in the experimental group by 38.5%. The course application of rIPC did not lead to significant changes in the indicators of physical performance in any of the animal groups.

In recent years, Russia was involved several times in military conflicts occurring in highland areas, such as Afghanistan, Nagorno-Karabakh, Chechnya, and Georgian-Ossetic borderline. Without preadaptation of troopers, military operations in highlands are associated with increased risks of acute mountain sickness, pulmonary edema, and brain edema, which interfere with combating and may result in noncombatant losses and even deaths. The present reviews addresses the prospects for using hypoxic preconditioning for accelerated adaptation of troopers to highlands.

The expansion of tasks, being carried out by military personnel in different climatic and geographical conditions, needs introduction of effective medical provision into the system of military training aimed at maintenance of high level of military efficiency in case of negative factors of the environment. At present the application of hypoxic factor is widely used in sports. In a number of Russian and foreign studies a high effectiveness of hypobaric hypoxia was shown for the correction of borderline functional states, enhancement of organism tolerance of pilots to flight factors, medical rehabilitation, therapy and prophylaxis of a number of diseases and so on. A research has been carried out that included the analysis of in- fluence of physical performance by volunteers in the course of a session of hypobaric hypoxia on factors of physical working capacity. Hypoxia was modelled in pressure chamber by means of barometric pressure decrease to the level equivalent to 3500 m altitude. In the time of presence «at the altitude» (30 min) physical activity was modelled by squatting performed by volunteers (30 squattings every 5 min) and stepping test performed throughout lift motion. Before hypoxic exposure, in the course of test trials and after its accomplishment the heart rate was assessed in volunteers. Also the results of functional probe performance (Shtange, Gench and Ruffier tests) and load testing on a treadmill («Running on the treadmill) were assessed. In the result of this study it was shown that the course of lift actions in pressure chamber leads to the increase of spare capacity of cardiorespiratory system and the development of human adaptation to the influence of moderate hypoxia levels. The most evident effect was observed at simultaneous impact of lift actions in pressure chambers and graduated exercise on the organisms of healthy volunteers.

In recent years, Russia was involved several times in military conflicts occurring in highland areas, such as Afghanistan, Nagorno-Karabakh, Chechnya, and Georgian-Ossetic borderline. Without preadaptation of troopers, military operations in highlands are associated with increased risks of acute mountain sickness, pulmonary edema, and brain edema, which interfere with combating and may result in noncombatant losses and even deaths. The present reviews addresses the prospects for using hypoxic preconditioning for accelerated adaptation of troopers to highlands.

We propose a new approach for the synthesis of biologically important nucleotides which includes a multi-enzymatic cascade conversion of D-pentoses into purine nucleotides. The approach exploits nucleic acid exchange enzymes from thermophilic microorganisms: ribokinase, phosphoribosylpyrophosphate synthetase, and adenine phosphoribosyltransferase. We cloned the ribokinase gene from Thermus sp. 2.9, as well as two different genes of phosphoribosylpyrophosphate synthetase (PRPP-synthetase) and the adenine phosphoribosyltransferase (APR-transferase) gene from Thermus thermophilus HB27 into the expression vectors, generated high-yield E. coli producer strains, developed methods for the purification of the enzymes, and investigated enzyme substrate specificity. The enzymes were used for the conversion of D-pentoses into 5-phosphates that were further converted into 5-phospho-α-D-pentofuranose 1-pyrophosphates by means of ribokinase and PRPP-synthetases. Target nucleotides were obtained through the condensation of the pyrophosphates with adenine and its derivatives in a reaction catalyzed by APR-transferase. 2-Chloro- and 2-fluoroadenosine monophosphates were synthesized from D-ribose and appropriate heterobases in one pot using a system of thermophilic enzymes in the presence of ATP, ribokinase, PRPP-synthetase, and APR-transferase.

We found a unique property of E. coli purine nucleoside phosphorylases to selectively perform the arsenolysis reaction of ribonucleosides in their active site without affecting β-D-arabinonucleosides. In the synthesis of modified β-D-arabinonucleosides from the corresponding ribonucleosides, the catalytical amount of sodium arsenate in the transglycosylation reaction provided a 95 to 98% conversion rate. Such an approach was shown to simplify the composition of the reaction mixtures and facilitate the isolation of the target nucleosides, particularly, vidarabine, fludarabine, and nelarabine.

Two genes of T. thermophilus HB27, TT_C1184 and TT_C1274, encoding proteins with phosphoribosyl pyrophosphate synthetase activity were cloned in an expressing vector pET23d+. Escherichia coli strains overproducing two relevant proteins in soluble forms were obtained. The methods of isolation of thermophilic phosphoribosyl pyrophosphate synthetases Tth PRPPS1 and Tth PRPPS2 were developed. The activities of these enzymes were determined as a function of concentration of metal ions, inorganic phosphate, and temperature. The kinetic parameters for basic natural substrates were calculated; the substrate specificity for different carbohydrate 5-phosphates of D-series was studied. It was shown that the two proteins differ significantly in these characteristics. According to the results and comparison of amino acid sequences of new proteins with those of other phosphoribosyl pyrophosphate synthetases, both enzymes belong to class I PRPPS.

Предложена новая стратегия биосинтеза биологически важных нуклеотидов, заключающаяся в мультиферментативном каскадном превращении D-пентоз в пуриновые нуклеотиды c использованием ферментов нуклеинового обмена термофильных микроорганизмов (рибокиназы, фосфорибозилпиро- фосфатсинтетазы и аденин-фосфорибозилтрансферазы). Клонирован ген рибокиназы термофильного микроорганизма Thermus sp. 2.9, два разных гена фосфорибозилпирофосфатсинтетазы (PRPP-cинтетазы) и ген аденин-фосфорибозилтрансферазы (APR-трансферазы) из Thermus thermophilus HB27. Получены высокопродуктивные штаммы-продуценты Escherichia coli, разработаны методы выделения упомянутых ферментов, изучена их субстратная специфичность. Показана возможность использования этих фер- ментов для превращения D-пентоз в 5-фосфаты, а затем под действием рибокиназы и PRPP-cинтетаз - в 5-фосфо-α-D-пентофуранозо-1-пирофосфаты, конденсация которых с аденином и рядом его структурных аналогов, катализируемая APR-трансферазой, приводила к получению искомых нуклеотидов. На примере 2-хлор(фтор)-аденозинмонофосфата (2Cl-AMP и 2F-AMP) показана возможность использования системы термофильных ферментов в одном реакционном объеме для получения биологически активных нуклеотидов из D-рибозы и соответствующих гетерооснований в присутствии ATP, рибокиназы, PRPP-cинтетазы и APR-трансферазы.

We studied the effects of 2-(hexyl(methyl)amino)methyl)pyridyl-3-dimethyl carbamate (OPDC), a structural analogue of aminostigmine oxalate, on memory formation in rats with toxic scopolamine-induced amnesia. It was shown that OPDC in non-toxic doses (1/215 LD50) has significant anti-amnesic action. Ipidacrine and galantamine in the doses similar to toxic doses (1/17 and 1/6 of LD50, respectively) induced the retention of memory trace. Administration of aminostigmine (1/11 of LD50) induced unstable anti-amnesic effect in the model of scopolamine-induced amnesia.