This is a short review concerning the problem of the germ line «immortality» which was already formulated by A. Weismann at the end of the 19th century. Over the following years, it attracted the attention of many gerontologists who tried to understand the mechanisms of infinite transfer of genetic information from generation to generation with the help of germ cells, which, in contrast to somatic cells, avoid aging in this way. However, it remained unclear how the germ cells of women, which are in fact a population of non-dividing cells (it is similar to stationary phase aging non-subcultured cell culture), provide the mentioned immortality of the germ line. The distinguished Russian gerontologist Zh.A. Medvedev, who passed away recently, published in 1981 his brilliant work «On the immortality of the germline: genetic and biochemical mechanisms. A review», the main points of which are relevant up to today. His paper just discusses the possible mechanisms of such «immortality». They are analyzed in detail in the current article and boil down mainly to the existence of a number of barriers that, in most cases, do not allow progeny to emerge from «old» germ cells (although certain «rejuvenating» processes in the gametes still go). Therefore, children are being «born young.» Some alternative approaches to explanation of the immortality of the germ line are also considered. Special attention is paid to «parental age effect» and the role of eggs and sperm cells in the phenomenon.

The spatial distribution of picocyanobacteria on the arctic longitude transect passing through the shelf of the Kara, Laptev and East Siberian seas from 58° to 168° E was studied. In the Kara Sea the picocyanobacteria abundance averaged 0.48±1.2 10⁹ cell/m³, in the Laptev Sea — 0.16±0.24∙10⁹ cell/m³, in the East Siberian Sea — 0.25±0.43∙10⁹ cell/m³. The abundance fluctuations of photoautotrophic prokaryotes were determined by the presence of allochthones picocyanobacteria sources - river runoff and transformed North Atlantic waters. Highest abundances were observed in the areas of the runoff influence of the Siberian Rivers Ob, Khatanga, Indigirka and Kolyma and averaged 0.5∙10⁹ cell/m³ (river Ob), 0.2∙10⁹ cell/m³ (river Khatanga), 0.4∙10⁹ cell/m³ (river Indigirka) и 1.6∙10⁹ cell/m³ (river Kolyma). The average contribution of picocyanobacteria to the total abundance and biomass of picoforms in the western part of the Kara Sea was 37% and 36% respectively. In other areas, the average contribution of picocyanobacteria to the total abundance of photo trophic picoplankton did not exceed 7%, to the total biomass — 6%. A highly reliable (p<<0.01) positive correlation between the abundance and biomass of picocyanobacteria and the water temperature (p = 0.003) was revealed over the entire array of data obtained.

In laboratory conditions, the process of sexual reproduction of the Black Sea diatom Climaconeis scalaris (Brebisson) E.J. Cox, 1982 was initiated and studied. A crossing system of this species allows both homo- and heterotallic reproduction. The sexual process is allogamous. During active gliding of diploid mother gametangial cells relative to each other, mucilage was excreted, forming a mucilage track. Each gametangium in a pair produced two elongated cylindrical with rounded ends haploid gametes, which were largely morphologically and behaviorally isogamous. The division of the protoplast of the gametangial cell occurred in the transapical plane without rearrangement of gametes. Growing auxospores were located parallel to the parent frustules. Data on changes in the cell size, number of chloroplasts, as well as the position of cardinal points in the life cycle of the investigated species were obtained.

First data on the species diversity of testate amoebae of the Coco River in the provinces of Quangnam and Danang (Vietnam) was presented. A total of 55 species and subspecies of testate amoebae belonging to 9 genera and 6 families were identified from 28 samples. Species diversity of testate amoebae of plankton was higher than the bottom samples. The highest frequency of occurrence being of Centropyxis aculeata (64.3%), Netzelia wailesi (39.3%), Difflugia acuminata (32.1%), Arcella discoides scutelliformis (28.6%) and Lesquereusia modesta (28.6%). The most species-rich genera are Difflugia (25), Arcella (12), Centropyxis (5) and Netzelia (4). The species accumulation curve based on the entire dataset was unsaturated and described by the equation y = 12.56N⁰⁴⁶. The average species richness of testate amoebae per sample in plankton (13.0 ± 3.1) is statistically higher than in the bottom samples (1.8 ± 1.5) (p < 0.001). The result of the redundancy analysis shows that the studied hydrochemical water characteristics (temperature, pH, dissolved oxygen, electrical conductivity and salinity) explained only 31.6% of the variation of testate amoeba diversity, wherein the first and second axes explained 11% and 10.2% of this variation, respectively.

In experiments on rats, we compared the influence of anxiolytic diazepam and nootropics piracetam and mexidol on passive avoidance conditioning (PAC) in a three compartment apparatus that consisted of a light compartment, a dark dangerous compartment in which foot shock was delivered and a dark safe one where the rats were not punished. Electric foot shock during PAC caused a sharp increase in the latent period of the central compartment leaving during the testing in the control animals, but did not lead to the safe compartment choice. Based on these data on the differential impact of the foot shock on PAC, we formulated the assumption that learning processes, which determined the motor response delay and the safe compartment selection, had different associative nature. The increase in the latent period is associated with the classical fear conditioning regardless of the place of the current impact. The safe compartment choice, on the contrary, is associated with the memory trace formation about the location of the foot shock exposure. The use of pharmacological substances that affect fear and memory in different ways gave additional arguments in favor of the assumption of various associative processes that determined PAC. Reducing the level of fear with diazepam reduced the latent period of motor response relative to the control value, but did not affect the choice of a safe compartment. In contrast, the mnemotropic properties of piracetam and mexidol increased the preference for a safe compartment without increasing the latent period. These differential pharmacological effects confirm that PAC is based on the conditioned responses of fear, which causes an increase in latent period of leaving the central compartment, and on the memory of the electrical exposure location which provides the safe compartment choice.

NRT1.1 nitrate transporter acts as nitrate sensor in some plant responses. We tried to check if it may be involved in the control of cytokinin level in the plants known to be involved in the growth responses to nitrate level. In accordance, we followed the effects of NRT1.1 gene mutation in chl1-5 plants on hormonal and growth responses to nitrogen starvation. Two types of experimental design were used: (1) plants were placed on either Hoagland-Arnon or modified solution, where potassium and calcium nitrates were substituted with their chlorides; (2) Pryanishnikov medium was used, where ammonium nitrate serves as the source of nitrogen, starvation being modeled by its withdrawal from the medium. We were first to show that mutation of the NRT1.1 resulted in a decline in cytokinin level in the roots of chl1-5, while roots of wild type plants were longer in accordance with lower cytokinin content in them, the hormone being known to inhibit root elongation. Cytokinin content decreased in Columbia plants paralleled by acceleration of root elongation in response to both variants of nitrogen starvation, while chl1-5 roots responded in this way only when nitrogen was withdrawn from Pryanishnikov solution, while substitution of nitrates by chlorides in the Hoagland-Arnon solution had no effects on either chl1-5 roots length or cytokinin content in them. The results suggested the involvement of NRT1.1 transceptor in the control of cytokinin level and root elongation rate in the nitrate, but not in ammonium starved plants, confirming the specificity of response.

The current problem with phosphorus fertilizers are shortage of rock phosphate from which it is produced and adverse impact of their production and use on the environment. A promising solution is use of phosphorus-rich biomass of microalgae as biofertilizer, but possible impact of such fertilizers on the biological activity and microbiome of soils remain unknown in many aspects. We investigated the effect of Chlorella vulgaris IPPAS C-1 biomass application on yield, biological activity, efficacy of the rhizobia- and cyanobacteria-based growth promoting formulations, as well as the microbiome of the soil during cultivation of beans (Phaseolus vulgaris L.) cvr. «Strela». Total and specific yield, actual nitrification and denitrification, carbon dioxide and methane emission were determined for soil samples from the rhizosphere. The taxonomic structure of the prokaryotic community of the bean rhizosphere was determined by NGS of 16s rRNA gene amplicons on the Illumina platform. The metagenomic data were analyzed using software tools QIIME and VAMPS. It was found that the application of biomass of C. vulgaris IPPAS C-1 as a phosphorus biofertilizer increased the bulk yield of beans. It also allowed to achieve the specific yield (per plant) level provided by traditional fertilizers. The biomass application did not (i) impact the biological activity of the soil, (ii) did not increase the level of denitrification, and (iii) did not increase significantly the soil emission of the «greenhouse gases». The Chlorella biomass application hamper the growth-promoting effect of the bacterial preparations made from rhizobia and cyanobacteria. Also, no significant changes in the taxonomic composition of the soil of the rhizosphere microbiome upon the application of the Chlorella biomass were revealed. Collectively, the results indicate the possibility of at least partial replacement of chemical fertilizers with phosphorus biofertilizers from microalgae biomass in the field growing of beans.

Currently, biological scaffolds composed of extracellular matrix (ECM) are being examined actively for the needs of regenerative medicine. ECM substrates are prepared by decellularization and used to deliver cells to damaged tissue. Native scaffold of ECM have an advantage over bioengineered ones because ECM retains natural biologic cues that provide efficient reparative cell functions. Mesenchymal stromal cells (MSCs) have multipotent potential of differentiation and secrete a wide range of bioactive molecules. In this regard, MSCs are important intermediaries for tissue repair. The ECM as a critical component of the MSC niche modulating their functional activity, including migration, proliferation and differentiation, as well as supports their potential for self-renewal. In vitro investigations would be useful in elucidation of how biological scaffolds can affect the reparative functions of MSCs. There are several different protocols for decellularization. Since ECM of various cell types differs qualitatively and quantitatively, these protocols should be optimized for each specific case. In the present study we compared the effectiveness of approach to prepare decellularized ECM (dcECM) of adipose-derived MSC (adMSC): Triton X-100/NHOH solution in phosphate buffered solution or HO, and the possibility of using dcECM after spheroids were formed. ECM-derived substrates were analyzed with immunocytochemistry and scanning electron microscopy. During long-term сultivation MSСs prodded a well-developed EСM, which after treatment with phosphate buffered solution of Triton X-100/NH4OH maintaining the struсture dose to native one. It was impossible to receive a uniform dcECM layer, when water solution of Triton X-100/NH4OH was used. On the scanning electron microscopy images single fiber of ECM were revealed in this case. We detected fragments of ECM and cells after spheroids formation upon of RGD peptides treatment. Therefore, this method was not effective for obtaining dcECM of adMSCs.

The universal response of Escherichia coli to stress is the enhancement of the synthesis of specific histone-like Dps proteins that bind bacterial DNA. As a result, two-dimensional and three-dimensional crystalline arrays can be observed in the cytoplasm of starving bacteria. We selected the conditions for obtaining in vitro cocrystals of DNA-Dps and studied their elemental composition using analytical electron microscopy. We found that Dps in the co-crystal retains its ferritin-like activity, that is, it can stimulate the oxidation of Fe₂+ ions to Fe₃+ and facilitate the accumulation of iron in the form of Fe₂O₃ in the inner cavity of the oligomer.

Long-distance interaction plays an important role in the regulation of eukaryotic genes. Chromatin structure is involved in the process, but the role of histone modifications has not been studied. In the present work the role of acetylation Н4К16 (Н4К16-Ac) to enhancer-promoter communication (EPC) was analyzed. This modification is associated with euchromatin and is involved in the decompaction of chromatin fibers. We have shown that the effect of H4K16-Ac on EPC in vitro depends on the level of chromatin assembly. EPC in chromatin, which lacks nucleosomes at random positions on DNA, is inhibited in the presence of H4K16-Ac. At the same time, EPC in chromatin, in which nucleosomes occupy all available positions on DNA, is somewhat stimulated in the presence of H4K16-Ac.

The paper studies the influence of the Ti-Zr-Nb (TZN) shape memory alloys surface on adhesion, proliferation, viability and actin cytoskeleton organization of osteoblast-like cells MG-63. The studied materials have a unique combination of mechanical properties that determine their prospects for creating bone implants with high biomechanical compatibility: low value of the Young’s modulus and superelastic behavior, similar to the behavior of bone tissue. We used thin plates of the experimental alloy TZN and the Ti-Al-Nb medical alloy (TAN) as a control material. A study of the growth dynamics of the MG-63 cell culture was made using the MTT test and counting the number of nuclei per unit area using scanning microscopy. It was found that on 4 and 7 days the number of cells on the TZN alloy is higher than on the TAN alloy. This may be due to the influence of the qualitative and quantitative composition of materials on the surface microstructure and chemistry. The viability over the cultivation time was close to 100% on both alloys. The analysis of cytoskeleton images showed the predominance of fibrillary actin on samples of the TZN system, as well as the organization characteristic of fibroblast-like polygonal cells.

Research on all factors that contribute to the carbon balance in the biosphere is of paramount importance, owing to the current increase in air carbon dioxide content. This work presents data on the carbon dioxide exchange of the needles of the common spruce (Picea abies L.) and the douglas-fir (Pseudotsuga menziesii L.) in an urban environment as exemplified by Moscow. It was established that a warm spell in autumn contributed to the prolongation of the period of carbon dioxide uptake by coniferous trees. Our analysis of the impact of environmental factors on needle photosynthetic activity revealed that photosynthesis intensity only depends on the illumination level. The midday increase in air temperature failed to affect photosynthesis intensity, probably because the plants were adapted to low night and morning air temperatures According to the regression analysis data obtained, the dependence of СО₂ assimilation on illumination represented a logarithmic curve; the approximation validity coefficient (R²) being 0.8. The impact of environmental conditions on conifer photosynthesis in autumn proved to be species-specific. The common spruce exhibited the maximum resistance to environmental factors, and its photosynthetic activity was 1,4 fold higher than that of the douglas-fir. Calculations revealed that the СО₂ assimilation level in the common spruce and the douglas-fur exceeded the light respiration level 3,6- and 2,7-fold, respectively, which points to a positive carbon dioxide exchange “balance sheet” and highlights the important role of coniferous trees in regulating the carbon balance of an urban ecosystem.

Aging organisms die out in accordance with the «Gompertz law», i.e. the probability of their death increases with age. Survival curve construction is the main tool for gerontologists to study aging and test anti-aging drugs. The analysis of survival curves includes obtaining some indices characterizing aging of the population, for example, average and maximum life span, mortality rate, and aging rate. Testing of geroprotectors can be correctly performed only by obtaining such curves. The dying out of stationary cell populations - bacteria, yeast, and mammalian cell cultures -also occurs in accordance with the Gompertz equation. In this regard, it is reasonable to use the construction of survival curves and their analysis to study the «aging» of non-subcultured cell cultures and testing of anti-aging drugs on them. We used this approach in our own experiments, due to which we were able to detect the positive anti-aging effect of the Quinton Marine Plasma on stationary phase aging culture of Chinese hamster cells.