Fourier transform infrared difference spectroscopy was used to study the effect of millimeter-range electromagnetic radiation on the structure of bacteriorhodopsin under lighting conditions. A detailed analysis of the Fourier IR spectra revealed pronounced structural changes in the region of amide I, amide II and rearrangement of the hydrogen bond network. The well-resolved peaks of the amide bands made it possible to recognize two different components (α-I and α-II) of the α-helical conformation of the opsin. Irreversible conformational changes of bacteriorhodopsin in purple membranes detected by Fourier IR difference spectroscopy suggested that microwaves induced structural rearrangements of proteins unrelated to temperature.

The maximum hypothermic storage time of amphibian oocytes is several hours, which is due to the peculiarities of the structure of the cell envelope. The authors of this paper have already demonstrated the possibility of increasing the storage period of unfertilized oocytes of the common frog ( Rana temporaria ) up to 5–7 days. The aim of the current study was to determine the possibility of using a 6.5 atm gaseous mixture of carbon monoxide and oxygen, for prolonged hypothermic preservation of unfertilized oocytes for 4 to 12 days. After four days, oocytes stored under CO+O 2 conditions exhibited fertilization and hatching rates that were 1.6 and 2.2-fold higher than control, respectively. While no oocytes in the control group survived to day twelve, oocytes held under CO +O 2 gas exhibited a 39±14% (38 out of 99 oocytes in total) fertilization rate, however only 1±2% (1/99) of those hatched. This approach is promising for the storage of genetic material from female amphibians, particularly in respect to managing and restoring endangered species, but may also be applicable to oocytes of other classes of vertebrates.

In this work, a multilateral analysis of submicron heterogeneities (SMH) spontaneously formed in aqueous solutions of sugars - glucose, fructose and sucrose - was carried out at 25 degrees C using laser scattering methods. The hydrodynamic diameters of SMH in 0.5 mol% solutions are 100-150 nm and vary slightly over a wide range of concentrations. However, the geometric diameters of SMH turn out to be much larger - 150-250 nm. This observation assumes that SMH are rather loose objects. The absence of depolarization of scattered radiation shows that the shape of MH is close to spherical. A new approach based on the methods of dynamic and multi-angle static light scattering using the Mie theory has been developed, which allows determining the refractive index of SMH. In 0.5 mol% solutions of sugars, the refractive index of SMH differs from the surrounding solution by no more than 0.005 for glucose and fructose and no more than 0.01 for sucrose. This corresponds to a 1.8-fold higher concentration of sugars in SMH compared to the average concentration in solution. Although SMH in sugar solutions are practically invisible due to the very small contrast, their numerical concentration is quite large, similar to 10(11)-10(12) ml(-1), and they occupy a similar to 0.1-1 % volume fraction of the solution. Dispersed and optical characteristics of SMH depend on the type and concentration of sugar.

Fourier transform infrared (FTIR) difference spectroscopy was used to study the effects of microwaves radiation on the structure of bacteriorhodopsin under light condition. The detailed FTIR spectral analysis revealed the pronounced structural changes in amide I and amide II regions as well as the rearrangements of the hydrogen-bonding network. Well-resolved peaks of amide bands allow accurate determination of two different components (α-I and α-II) of an α-helical conformation of opsin. Irreversible conformational changes of bacteriorhodopsin in purple membranes, detected by FTIR difference spectroscopy, suggest that regardless of temperature, microwaves induce protein structural rearrangements.

It has been shown that a decrease in background production of reactive oxygen species in peritoneal neutrophils of mice after a short-term (40 min) stay in hypomagnetic conditions (residual field of 10 nT) at physiological temperatures, detected by the method of lucigenin-dependent chemiluminescence, was not accompanied by a violation of the chemiluminescent response to respiratory burst activators of formylated peptide N-formyl–Met–Leu–Phe (fMLP) and forbol ether forbol-12-meristate-13-acetate (FMA). These results were obtained by activated chemiluminescence method using lucigenin and luminol and various combinations of activators for the production of reactive oxygen species (forbol-12-meristate-13-acetate and/or N-formyl–Met–Leu–Phe). The study, together with the previously obtained results, makes it possible to exclude the systems controlling the respiratory burst in neutrophils from the main targets and acceptors that react to short-term deprivation of a magnetic field.

This study shows that the background formation of lower levels of reactive oxygen species in mouse peritoneal neutrophils after short-term (40 minutes) exposure to hypomagnetic fields with ~10 nT residual field at physiological temperatures, which has been detected by use of lucigenin-dependent chemiluminescence, is not accompanied by the impairment of chemiluminescence response of neutrophils to respiratory-burst stimuli: the formylated tripeptide N-formyl-Met-Leu-Phe (fMLF) and phorbol ester phorbol-12-myristate-13-ace-tate (PMA). These results were obtained with lucigenin or luminol-enhanced activated chemiluminescence and various combinations of reactive oxygen species production stimuli (phorbol-12-myristate-13-acetate and/or N-formyl-Met-Leu-Phe). Based on the results of the present work as well as on those of previous studies, this study reveal that the systems that control the respiratory burst in neutrophils can be excluded from a list of main targets and acceptors that respond to short-term deprivation of the magnetic field.

A concept on gut microbiota as one of the key players in maintaining the human health is becoming more and more actual [1, 2]. Currently two main strategies can be distinguished in gut microbiota valuable biological matter application in the therapy of various pathologies, transplantation and application of probiotic medications, which both are focused on restoration of balance of microorganisms. In this regard, development of new methods for long-term conservation of microbiota providing high conservation degree of species and quantitative composition and quantitative parity of the bacteria forming the microbiocenosis is more and more relevant.

The aim of the study was to evaluate the possibility of increasing the radioprotective potential of peroxiredoxin 6 (Prdx6) and its mutant form S32A by their combined use with geldanamycin (GA) for 3T3 fibroblasts irradiated with X-rays at a dose of 6 Gy. The mutant enzyme S32A, which does not have phospholipase activity, exhibits a more pronounced radioprotective activity when combined with GA. The use of this combination of radioprotective drugs completely abolishes the peak of NF-κB activity in irradiated 3T3 cells. Another transcription factor, p53, which is an indicator of the level of cell apoptosis and increases upon irradiation, is also reduced by S32A in combination with GA. The low-molecular-weight protein p21, which is a marker of cell senescence and whose production increases upon irradiation, is also normalized when S32A is used in combination with GA. In addition, the use of this combination of radioprotective drugs significantly reduces the stress response of 3T3 cells to X-ray irradiation.

Some current trends in the development of research on the effects and mechanisms of the biological action of weak and ultra-weak static magnetic fields, low-frequency alternating magnetic fields, combined magnetic fields, and radio frequency fields in combination with a static magnetic field are presented. Experimental studies in which interesting and somewhat unexpected effects of magnetic fields with strength significantly lower than the magnetic field of the Earth (including those with intensities close to zero) were observed, are considered. The data are given taking into account the materials of the joint annual meeting of the Society of Bioelectromagnetism and the European Association of Bioelectromagnetism “BioEM 2021” (September 26–30, 2021, Ghent, Belgium).

Представлены некоторые современные тенденции развития исследований в области эффектов и механизмов биологического действия слабых и сверхслабых постоянных, низкочастотных переменных и комбинированных магнитных полей, а также полей радиочастотного диапазона в сочетании с постоянным магнитным полем. В числе прочих рассмотрены результаты ряда экспериментальных работ с использованием напряженности магнитного поля значительно ниже окружающего магнитного поля Земли (в том числе с интенсивностями, близкими к нулю), в которых были обнаружены интересные и несколько неожиданные эффекты. Данные приведены с учетом материалов совместного ежегодного собрания Общества биоэлектромагнетизма и Европейской ассоциации биоэлектромагнетизма «ВioEM 2021» (26-30 сентября 2021 г., Гент, Бельгия).

We studied the effect of xenon on the survival rate of the spermatozoa of the common frog Rana temporaria during slow freezing with saturation of the suspension with xenon at a pressure of up to 1.2 bar. The cryoprotective properties of xenon were analyzed in comparison with nitrogen. No specific cryoprotective effect of xenon was revealed. Viability of spermatozoa pretreated with xenon at atmospheric pressure (0 bar) or under excess pressure of 0.6 bar and frozen in a cryoprotective medium with dimethylformamide, sucrose, and BSA did not differ significantly. The use of overpressure of xenon of 1.0 or 1.2 bar in the pretreatment and freezing process significantly impaired viability of the biomaterial.

The idea of using a higher pressure to reduce damage due to freezing has been thoroughly theoretically examined, while there is little experimental evidence on cryopreservation of living systems at a higher hydrostatic pressure. A study was made to assess the viability of HeLa cells at a pressure of 1.0–2.0 kbar, the toxic effects of five classical cryoprotectants under these conditions, and the viability of HeLa cells during slow (conventional) cryopreservation at a pressure of 1.0 or 1.5 kbar. High resistance to higher hydrostatic pressure was experimentally demonstrated for HeLa cells; i.e., 100% cell survival was observed after cell exposure to a pressure of 1.0 kbar for 60 min. The toxic effect of the cryoprotectants increased under pressure in the following order: glycerol < ethylene glycol < 1,2-propanediol = DMSO < DMSO + formamide. Glycerol and ethylene glycol were the least toxic and additionally exerted substantial baroprotective effects. A high cell survival rate of 83 ± 16% was achieved with 10% glycerol used for cryopreservation at a pressure of 1.0 kbar according to fluorescence staining data, but did not exceed the survival rates observed in control normobaric experiments. Freezing was carried out via slow conventional cryopreservation. Different results might be obtained by using vitrification to freeze biological material at a higher pressure.

The effect of different pressure levels of a gas mixture of carbon monoxide and oxygen on the shelf life of rat heart tissue during prolonged hypothermic (4°C) gas preservation with the durations of sample storage of 24, 36, and 48 h was evaluated. The pressure decrease of the CO/O2 gas mixture (in the ratio of 1 : 1) from 6.5 to 1.5 atm during 24 h preservation led to the appearance of myocardial infarction zones (17.74 ± 3.5% of the total sample area) and a violation of the contractile function of the ventricles. At the same time, the indicators of the heart shelf life after storage under pressure of 3.5 and 6.5 atm did not significantly differ. The advantage of the pressure of 6.5 atm compared to the pressure of 3.5 atm during 36 and 48 h preservation was observed. The myocardial infarction zones after 48 h of preservation were 33.65 ± 11.96% and 61.92 ± 6.38%, respectively. Exploratory introduction of argon to the gas mixture (CO : O2 : Ar = 2 : 2 : 1) for a possible synergistic increase in organoprotection in the experiments on heart preservation under the pressure of 3.5 atm did not result in significant improvement in the index of heart tissue shelf life. The potential mechanisms of the protective effect of the mixture of carbon monoxide and oxygen in hypothermic preservation are discussed.

В связи с развитием медицинских технологий все большую актуальность приобретает разработка методов длительной консервации цельной микробиоты кишечника человека, которые бы обеспечивали высокую сохранность, как в отношении видового состава, так и в отношении количественного паритета составляющих микробиоценоз бактерий. Исследовано влияние 5- и 10%-х растворов диметилсульфоксида, глицерина, этиленгликоля, желатина, полиэтиленгликоля, поливинилового спирта, фетальной сыворотки коров, а также фетальной сыворотки в комбинации с 5% диметилсульфоксида на выживаемость кишечной микробиоты человека в процессе криоконсервации в жидком азоте (минус 196 С, хранение до 7 суток). Наиболее высокие показатели выживаемости бактерий при криоконсервации достигнуты при использовании криозащитной смеси на основе фетальной сыворотки коров и 5%-го диметилсульфоксида: от 81 до 87% жизнеспособных клеток по данным флуоресцентного теста LIVE/DEAD при показателе интактной микробиоты, равном 88-90%. Эффективность выбранного криозащитного состава подтверждена также методом микробиологического культивирования в экспериментах по криоконсервации отдельных штаммов - характерных представителей микробиоты кишечника человека.

Показано, что импульсные магнитные поля (первый режим: длительность импульсов 2 мс, частота повторения 6.25 Гц, форма импульсов - колоколообразная; второй режим: длительность импульсов 1 мс, частота повторения 100 Гц, форма импульсов - колоколообразная) влияют на интенсивность люминолзависимой хемилюминесценции нейтрофилов в широком диапазоне величин импульсных магнитных полей (0.0004-10 мТл). Для проявления обнаруженных этим методом эффектов импульсных магнитных полей требуется добавка в суспензию нейтрофилов активатора продукции активных форм кислорода - форбол-12-меристат-13-ацетата. Однако этот механизм действия импульсных магнитных полей на продукцию активных форм кислорода в нейтрофилах не является единственным, так как люцигенин-зависимая хемилюминесценция в системе без активаторов также реагирует на их действие.

Показано, что 30-минутная инкубация суспензии нейтрофилов в «нулевом» магнитном поле, создаваемом системой магнитных экранов из пермаллоя (остаточное постоянное магнитное поле не превышает 20 нТл), приводит к существенному снижению (на 48%) интенсивности ее люцигенин-зависимой хемилюминесценции, определенной сразу после окончания воздействия гипомагнитных условий. Через 20 мин после пребывания в гипомагнитных условиях (при последующей 20-минутной инкубации нейтрофилов в геомагнитном поле) степень проявления различий между контрольными и опытными образцами полностью сохраняется. При увеличении длительности последующей после пребывания в «нулевом» магнитном поле инкубации экспериментальных образцов в геомагнитном поле (постоянное поле 44 мкТл) до 40 и 60 мин различия между ними и соответствующими контрольными группами образцов уменьшаются до 32 и 22%.

The effects of air, helium, argon, xenon, and sulfur hexafluoride on the integrity of the ice structure formed when water and a cryoprotective solutions were frozen in the temperature range from 0 to –50°C was studied using optical microscopy. It was shown that the crystallization of a water drop with a volume of approximately 200 μL in the air atmosphere occurred with a violation of the integrity of the ice structure. Formation of gas microbubbles with a diameter of up to 250 μm was observed in the frozen samples. Purging of argon, xenon, or sulfur hexafluoride over the surface of a water drop before freezing reduced the maximum size of microbubbles to 100 μm. Purging of helium above the surface of water, DMEM (Dulbecco’s Modified Eagle Medium), and EuroCollins solutions made it possible to completely eliminate or significantly reduce the formation of gas microbubbles during crystallization. The ice formed in this case was characterized by a tendency to reduce the probability of cracking when cooled to –50°C, which can contribute to the survival of biological material during preservation. The addition of a cryoprotector, ethylene glycol, at a concentration of 1–10 vol % in the solution made it possible to reduce or completely prevent the release of microbubbles of gas during freezing. The mechanism by which this phenomenon occurred remains unclear. Addition of ethylene glycol at a concentration of 10 vol % or more also prevented ice cracking when it was cooled to –50°C.

Due to advances in medical technologies, it is an important problem to develop methods that allow safe and efficient long-term preservation of the human gut microbiota without substantially altering the abundance of the species and quantitative balance of components in the microbial community. The effects were studied of 5 and 10% solutions of dimethyl sulfoxide (DMSO), glycerol, ethylene glycol, gelatin, polyethylene glycol (PEG), polyvinyl alcohol (PVA), and fetal bovine serum (FBS) used alone or in combination with 5% DMSO, on the survival rates of human gut microbiota during cryopreservation in liquid nitrogen (storage at –196°C for up to 7 days). The highest survival rates of bacteria during cryopreservation were obtained with a cryoprotective mixture based on FBS and 5% DMSO: the viability was 81–87% by the LIVE/DEAD fluorescence viability assay and the intact microbiota index was 88–90%. The efficiency of the selected cryoprotectant composition was confirmed in microbiological cultures in experiments on cryopreservation of individual strains common to the human gut microbiota.

It has been shown that 30-min incubation of neutrophils in the presence of a near null magnetic field produced with the use of permalloy for magnetic shielding (a residual static magnetic field not greater than 20 nT) leads to a significant decrease (by 48%) in the intensity of lucigenin-dependent chemiluminescence measured directly after removal of the hypomagnetic field. At 20 min after being in hypomagnetic conditions (followed by a 20 min of incubation of neutrophils in the geomagnetic field), the degree of the differences between the control and experimental samples is completely preserved. When the time periods of incubation of experimental samples in the geomagnetic field (static magnetic field 44 μT) were extended (40 and 60 min) after exposure to a near-null magnetic field, the differences between experimental and appropriate control groups of samples were smaller, by up to 32 and 22%.

The role of two heat shock proteins, Hsp70 and Hsp90α, on stress response in mice with severe diabetes mellitus induced by a high dose of alloxan (500 mg/kg body weight), as well as in RIN-m5F β cells cultured in the presence of cytokines (IL-1 and TNF-α) was studied. Our results showed that severe type 1 diabetes mellitus (T1D) caused a higher expression of Hsp90α, but not Hsp70. Moreover, injections of the peroxiredoxin 6 antioxidant enzyme (PRDX6) did not affect the expression of these chaperones. Conversely, pro-inflammatory cytokines added to β-cells caused a significant increase in the expression of Hsp90α and, substantially, Hsp70. Moreover, cells cultivated in the presence of PRDX6 were more susceptible to the cytokine effect. Thus, in the course of severe alloxan-induced T1D, no protective role of the heat shock proteins, was revealed, and their expression level was not increased by PRDX6. At the same time the protective potential of these proteins was shown in vitro with the use of RIN-m5F β cells. Thus, the system of heat shock proteins was unable to prevent the devastating effects of severe T1D accompanied by high animal mortality.