A small cohort of a specialized myocytes in the intercaval region constitutes a dominant heart pacemaker, so called sinoatrial node (SAN). The SAN determines proper heart automaticity throughout life in mammals including human. A complicative histological organization, specific electrophysiology of pacemaker cardiomyocytes and unique genes expression pattern underlie SAN functioning. The development of the SAN starts very early in embryogenesis and continue till late prenatal period. The clarification of molecular mechanisms that underlie SAN origin facilitates bio-artificial pacemakers development, understanding of many cardiovascular diseases including hereditary, developmental or acquired arrhythmias. In addition, the advance in cardiac or somatic cell reprogramming that result from the understanding of SAN embryogenesis promotes cardiac cell-based repair, cell therapy and reversion of pathological remodeling in the heart. To date, a significant progress is achieved in the field of genetic and molecular pathways identification that control pacemaker calls nature, govern morphological and functional maturation of the cardiac pacemaker during ontogenesis. In this review a detailed overview of the key transcription factors, morphogenetic signaling molecules (BMP, podoplanin, VEGF, PDGF) and regulatory pathways (Wnt, Wt1, Slit/Robo, RhoA) involved in (epi)genetic control of the pacemaker myocytes progenitors specification and differentiation, as well as in the functional SAN development is presented.

Nanoparticles (NPs) are dangerous micro-pollutants that exhibit biotoxicity even in low (nanogram range) concentrations. Apart from direct toxicity to living organisms, NPs can absorb and transfer organic or inorganic toxicants, as well as potentiate the toxicity of other micropollutants. Increasing use of NPs in the industrial and domestic applications leads to their increased production and discharge into the environment giving rise to diverse risks for ecosystems. These risks are exacerbated by the resilience of NPs to biodegradation in natural ecosystems and traditional wastewater treatment plants. Efficient NPs removal technologies are complex and expensive, so they cannot be affordably replicated in common wastewater treatment plants. Despite the risks associated with NPs, humanity will not abandon their use in the nearest future, since the NPs are now at the foundation of many modern technologies. Biodestruction and biosorption of NPs using microalgae cultures and algal-bacterial consortia are considered promising approaches regarding the environmental safety and conservation of natural resources. However, the progress of this approach is hindered by paucity and fragmentary nature of the information about the effects of NPs on microalgae cells and microbial communities. This review attempts to fill this gap, at least partially, by considering common industrial NPs types based on metals and their oxides, as well as carbon nanomaterials. The pathways of their entry into aquatic ecosystems, toxicity to living organisms, accumulation and biotransformation in cells, synergistic effects of NPs in combination with heavy metals and antibiotics, as well as methods of bio-removal of NPs and nanomaterials from aquatic ecosystems using microalgae are discussed.

The accessibility of DNA is important for the regulation of gene expression and provided by regulatory factors, such as FACT protein complex. As it was shown before, in the presence of Nhp6 protein, yeast FACT (yFACT) induces ATP-independent reversible unfolding of nucleosome, but the detailed mechanism of this process is unknown. In this study, we investigated whether presence of single Nhp6 molecule is sufficient for the unwinding of nucleosomal DNA by the yFACT factor, or whether the reorganization of the nucleosome structure requires the combined action of yFACT and several Nhp6 molecules. Analysis of the protein complex in the absence of nucleosomes by native gel electrophoresis has shown that yFACT itself can bind at least three Nhp6 molecules. Using single particle microscopy based on the Foerster resonance energy transfer, it is shown that with an increase in the ratio yFACT:Nhp6 from 1:10 to 1:1 at a constant concentration of Nhp6, the ability of yFACT to unfold nucleosomes does not increase, but decreases. Therefore, the unfolding of the nucleosome requires the binding of more than one Nhp6 molecule in the complex nucleosome:yFACT:Nhp6. The obtained data clarify the existing model of the reorganization of nucleosome structure by yFACT.

Small regulatory molecules such as indole and polyamines are involved in the regulation of various processes in bacteria, including the response to antibiotics. It is known that small regulatory molecules can influence each other, but there is no information on the interaction of indole and polyamines. We have shown here that indole at micromolar concentrations reduces the susceptibility of Escherichia coli to fluoroquinolone, beta-lactam and aminoglycoside antibiotics. Indole had a stronger effect on the antibiotic susceptibility of bacteria capable of synthesizing the polyamines putrescine and spermidine as compared to a polyamine-deficient isogenic strain. Exogenous indole increased intracellular level of putrescine and spermidine by 2 and 2.5 folds, respectively, and had no effect on the cadaverine level. The supplementation of cultivation media with common bacterial polyamines, putrescine, cadaverine, and spermidine, did not influence the production of indole by E. coli cells. The addition of spermine, a polyamine mainly synthesized by eukaryotes, increased the release of indole into the medium by E. coli cells (by no more than 20%). Thus, indole reduces antibiotic susceptibility of E. coli to antibiotics with different mechanisms of antibacterial action, in particular, by increasing the amount of polyamines in bacterial cells.

The number of microplastic particles (MPs) in the environment is constantly increasing as a result of the decay of plastic waste, the incineration of which is associated with air emissions and the concentration of toxic combustion products in ash residues. Although numerous researchers have studied the effects of MPs on living organisms, only a small part of the published data is devoted to the study of the long-term toxic effects MPs and combustion products of plastic on phytoplankton organisms. The effect of different types of MPs and plastic incineration ash on the structural and functional growth parameters of a green microalga Scenedesmus quadricauda culture, used as a test object, was studied in a chronic experiment lasting 21 days. The development of the species was studied with the addition of 5 types of weathered MPs samples, obtained from macroplastics, collected in the supralittoral of the Barents Sea and one unweathered control sample at a concentration of 3 mg/L. In terms of changes in the number of Scenedesmus quadricauda cells, the following toxicity series was obtained in descending order: PU (polyurethane foam, weathered) > HDPE (food package, white, weathered) > HDPE (food package, red, weathered)> EPS (packaging material, weathered) > EPS (packaging material, unweathered) > PP (ship rope, weathered). In terms of the efficiency of photosynthesis (maximum quantum yield of PSII photochemistry (FV/FM)), polyurethane foam was found to be non-toxic, while other samples of MPs had a weak toxic effect. The effect of MPs on the culture caused a mosaic response, assessed by different parameters of the test object state: a strong inhibition of culture growth (with the addition of polyurethane foam) can be accompanied by a significant increase in thiobarbituric acid reactive substances (TBARS) in microalgal cells, while photosynthesis efficiency may not change. The toxicity of the residual ash obtained from the incineration of a mixture of weathered macroplastics was significantly higher than the toxicity of microplastics. Residual ash was studied at concentrations of 0.01, 0.1, 1, 10, 100 and 1000 mg/L and the toxicity was detected in terms of the change in the cell number only at a concentration of 1000 mg/L, in terms of the photosynthesis efficiency – at 0.01 mg/L, and by the change in the amount of TBARS in microalgal cells – at 0.1 mg/L and above.

2,6-dichlorophenolindophenol (DCPIP) is a redox indicator widely used to study electron transfer reactions in biological systems, including in the process of photosynthesis. DCPIP exists in solution in two forms – “pink” and “blue,” which transform into each other during protonation/deprotonation. Upon reduction, the DCPIP is discolored. We investigated the pH-dependence of DCPIP reduction rate in the presence of the photosystem II (PSII) at two wavelengths – 522 nm (isobestic DCPIP point) and 600 nm (near the absorption maximum of the deprotonated “blue” form). It was shown that in experiments with change of the pH medium, measuring at a wavelength of 600 nm requires corrections related to changing the ratio of the “blue” and “pink” forms of the acceptor, as well as using the pK parameter of this acceptor, whose values рК vary in various sources, to calculate the DCPIP reduction rate. Measurements at the isobestic point (522 nm) avoid these complexities. We also found that the maximum at the pH-dependence of the DCPIP reduction rate by PSII shifted by about 1 unit to the acidic region relative to the maximum of the acceptor pair 2,6-dichloro-p-benzoquinone – potassium ferricyanide reduction rate pH-dependence. This shift may be due to the lower availability of the QB site on the acceptor side PSII for the charged deprotonated DCPIP form compared to the uncharged protonated form.

Universal stress proteins (USP) are potentially involved in the processes that control plant morphogenesis, in which phytohormones play an important role. In this study, we searched for the genes of Arabidopsis thaliana USP that modulate their expression in response to the action of phytohormones. Fifteen USP genes have been identified whose expression is differently regulated by two or more phytohormones. Moreover, the accumulation of transcripts of the most studied genes was observed under the action of hormones involved in the formation of plant resistance to stress – abscisic acid, ethylene, and methyl jasmonate. At the same time, auxins and gibberellins, hormones that regulate plant growth, suppressed the expression of the studied USP genes. The obtained results revealed potential genes of USP, whose functional activity may be directly or indirectly associated with phytohormone-dependent processes that ensure plant growth under normal and stress conditions.

Fibroblasts of the dermis are a heterogeneous population – among them there are several subpopulations that differ in origin, anatomical regional specificity and location in the thickness of the dermis. We investigated some phenotypic and functional features of fibroblasts of the papillary and reticular dermis of human skin. It was found that the introduction of reticular fibroblasts into the primary culture with an oxygen level reduced to 5% increases the efficiency of obtaining this population of fibroblasts. Morphometric analysis of cultured fibroblasts of the studied populations, comparison of the strength and rate of collagen gel contraction, and data on the expression levels of CD90 and CD73 obtained by flow cytometry showed significant differences in fibroblasts of the papillary and reticular layers of the human dermis of the temporal region.

Assessment of the safety of genetically modified plants for the microbial community of the soil and the environment is important due to the increase in the diversity of genes involved in the creation of genotypes of crops resistant to edaphic stress. Genetically engineered tobacco (Nicotiana tabacum L.) with the ability to synthesis glycinebetaine in chloroplasts was established by introducing the соdA gene for choline oxidase from soil bacteria Arthrobacter globiformis. Synthesis of glycinebetaine helps to stabilize cells under salt stress. Plants wild type (variety Samsun) and the CodA 38 transgenic line were grown in pot culture on a normal soil background and under conditions of salt stress caused by 150 mM NaCl. The abundance, diversity and structure of actinomycete complexes were compared at the generic and species level (Streptomyces) using nonparametric rank method of statistical analysis. The obtained data indicate the absence of significant (p = 0.95) changes in the number and taxonomic structure of actinobiota, frequency of occurrence of streptomyces-antagonists of phytopathogenic fungi and bacteria, streptomyces-cellulolytics in the rhizosphere of transformant plants with genetically increased resistance to salt stress. It is concluded that it is necessary to continue research on the specific reactions of soil and rhizosphere microorganisms to various categories of genetically modified plants.

The author’s view on the current state of gerontological research is presented. He believes that the widespread departure from the principles of classical gerontology, formulated back in the 20th century, has not been reflected in the works in the field of biology of aging (both theoretical and experimental) in the best way. The neglect of the fundamental principles of gerontological research has led to the fact that in most works the classical definition of aging as a set of age-related changes in practically healthy individuals, leading to an increase in the rate of mortality, is ignored. The emphasis is on assessing the average and maximum lifespan of the studied organisms, even if they are ageless. Extending the lifetime of such objects cannot be considered a modification of the rate of their aging. It is emphasized that special attention is now being paid to molecular age-related changes, which some gerontologists consider aging, although this is just its possible mechanism or consequence. However, geroprotectors are very often studied just by assessing the modification of the rate of such age-related changes. At the same time, as classical gerontology rightly believes, the principles of which the author urges to adhere to, without taking the survival curves of the control and experimental cohort, it is impossible to draw a correct conclusion about whether the studied compound is a geroprotector. And an approach to the formation of such cohorts is very important, including an assessment of the minimum required number of organisms in them, as well as the “quality” of their health. A couple of gerontological articles published in the most highly ranked scientific journals and therefore attracted a lot of attention of relevant specialists are considered. This attention was expressed, among other things, in the high citation rate of these works, although they were performed with significant violations of the principles of classical gerontology, which were subsequently identified by other researchers. It is also emphasized that at present the rating of a scientific journal for many gerontological readers has become much more important than the correctness of the results and ideas presented in the article. A list of methodological problems is given, which, according to the author, not only complicate the situation with modern gerontological research, but also make tangible progress in this area practically unattainable.

Influence of low-temperature atmospheric pressure plasma generated by a high-resource arc plasmatron in an air mixture with the addition of an inert gas and in pure inert gas on the culture of Paramecium caudatum cells was studied. The effect of the plasma composition and the time of its exposure on the level of acidity of the aqueous medium and the nature of cell death was found. The obtained results are discussed taking into account the effect of active radicals formed under the action of a plasma jet, as well as the delayed reaction of cells to plasma exposure.

Sodium ascorbate is a strong reducing agent able to participate in non-enzymatic reactions with reactive oxygen species. The research work was dedicated to screening of lactic acid bacteria (LAB) strains from the Collection of Microorganisms of the Department of Microbiology (Faculty of Biology, Lomonosov Moscow State University) and to selection of the most promising strains belonged to genera Lactobacillus and Lactococcus. We have investigated the ability to inhibit the ascorbate autoxidation by cells of 16 new strains of LAB from the Collection of Microorganisms of the Department of Microbiology, Lomonosov Moscow State University (CM MSU). Lactobacillus plantarum CM MSU 161 (42.9%), Lactobacillus plantarum CM MSU 520 (36.6%), Lactobacillus plantarum CM MSU 508 (33%) and Lactobacillus paracasei CM MSU 527 (38.1%) had the greatest inhibitory effect on ascorbate autoxidation. Lactobacillus acidophilus CM MSU 146, Lactobacillus plantarum CM MSU 162, Lacticaseibacillus rhamnosus CM MSU 529, Lactobacillus paracasei CM MSU 544, Lactobacillus caucasicus CM MSU 155, Lactococcus lactis ssp. lactis CM MSU 170 had no detectable effect on inhibition of ascorbate autoxidation. These strains were compared with strains from other collections. In particular, the majority of Lactobacillus plantarum strains as well as Lactobacillus brevis CM MSU 535 (20.7%) from the CM MSU demonstrated a higher percentage of inhibition of ascorbate autoxidation compared with the strains from the ATCC and the DSMZ collections. We have shown that this method can be used as an express testing to reveal the general ability of lactic acid bacterial cells to resist reactive oxygen species and to assess their antioxidant status. Thus, the ability to inhibit autooxidation of ascorbate can be used as one of the potential positive factors for selection of probiotics among LAB.