In this review, we tried to elucidate the origin and development of different animal and human cell culture methodologies used to evaluate the effects of various factors and substances in vitro. Organ cultures and conventional two-dimensional cultures of dissociated cells of various types, such as primary, tumor, induced pluripotent, stem, and etc. have their advantages and drawbacks but usually do not represent accurate models for studying biological processes that take place in living organisms. Nowadays high-throughput cell assays on the basis of various methods of signal detection (optical utilizing colorimetric, luminescent and fluorescent methods of detection and electrochemical) are widely used at early stages of drug development for selection of the most active compounds and evaluation of their cytotoxic effects. The use of animals as models for drug testing is being criticized because of the lack of correlation between the results obtained in studies on them and on humans, and also because of the high cost and ethical issues. Therefore, much effort is put to create models based on human cells. This is how cultures emerged that utilize a three-dimensional network to simulate the architecture of tissues in vivo, and then so-called “organs-on-chips” – microfluidic microdevices combining several types of cells, that replicate physical and chemical parameters of the microenvironment of cells in living organisms. In summary, experimental cell models have come a long way from the whole organs cultivated in a growth medium to almost complete reconstruction of organs in vitro based on the cutting-edge engineering approach with the use of different cell types. This currently enables to replicate complex biological processes and study the influence of different substances and factors on them more successfully.

Rotavirus infection is a rotavirus-associated disease. It is the main cause of severe diarrhea among children all over the world and one of the factors influencing the infant mortality. Today, only live attenuated vaccines are widely used for vaccination against rotavirus infection. Existing vaccines have demonstrated their effectiveness, but they have a number of side effects, primarily the risk of intussusception. Complications associated with the use of existing vaccines are usually associated with oral administration of drugs and the replication of attenuated live vaccines in the human intestine. In this regard, there is a need to design modern, effective and safe vaccines against rotavirus infection, unable to reproduce (to replicate) in the human body. Currently, modern vaccines against rotavirus infection are being developed and tested actively. These are recombinant vaccines with parenteral administration. The complicated antigenic structure of rotavirus is one of the main problems for the design of such recombinant vaccines. This review discusses the genetic and antigenic diversity of rotavirus strains and the geographical location of their epidemically significant variants. The role of capsid proteins in the formation of an immune response to the virus and the current state of development of new candidate recombinant vaccines against rotavirus infection are considered.

Study of the possibilities of virions and viral proteins modifications and structural remodelling is an important problem of the modern molecular virology. The method of thermal transformation of tobacco mosaic virus rod-like virions in structurally modified spherical particles, consisting of viral coat protein, was developed in our laboratory. These particles have unique adsorption and immunogenic properties. We developed a new candidate vaccine against rubella virus based on structurally modified spherical particles. Later we demonstrated the possibility of thermal remodelling of potato virus X filamentous virions. The present work is devoted to a comparative study of the thermal remodelling of viruses with different structure, belonging to various taxonomic groups. The formation of structurally modified spherical particles was shown during thermal treatment of rod-like virions with a helical symmetry (dolichos enation mosaic virus, barley stripe mosaic virus). The dependence of the sizes of the spherical particles (formed from dolichos enation mosaic virus) on the initial concentration of the virus was revealed. The process of thermal remodelling of alternanthera mosaic virus filamentous virions and virus-like particles was studied. Morphological changes of plant viruses with icosahedral symmetry were not observed during thermal treatment.

Phytoplankton communities can serve as bioindicators of water system condition. Model of the natural ecosystem can enable multivariate experiments on the effect of physical and chemical factors on biophysical and hydrobiological characteristics of phytoplankton. Creating of such a model requires selecting appropriate species of microalgae. This study has allowed for selecting six types from those available in museum to create a model algal community. We found that similar conditions are required for their optimal growth (light, temperature, medium nutrients supply). As a base medium it is proposed to use a medium with low nitrogen content. Under these conditions, the cells function in a proper way and the cultures show satisfactory growth, while the duration of reaching the stationary stage of growth (10–15 days) allows to have more experiments for a limited time. Cells of selected species have morphological differences that are sufficient for the automated identification within the polyculture. We have obtained the geometric characteristics of cells for computer counting of each community species on microphotographs.

The use of tissue-engineering constructs based on scaffolds that imitate the extracellular matrix of living tissue unveils new opportunities in the treatment of various pathologies and injuries associated with tissue and organ damage. Silk fibroin of silkworm Bombyx mori is a biocompatible and bioresorbable polymer with high mechanical strength and elasticity. These features allow creating scaffolds on its basis for regeneration of various tissues,  including bone tissue. In the present work fibroin scaffolds were obtained in form of porous sponges, films and hybrid scaffolds. The last ones are bilayer structures in which the porous sponges intrinsic three-dimensional structure is limited on the one side by the film. The structure of scaffolds and their biocompatibility was studied. The tests showed that immortalized and primary fibroblasts, as well as osteoblast-like cells, successfully adhere and proliferate on the surface of the studied scaffolds. Numerous osteogenesis foci were observed in the implant region in the in vivo experiments on the rat femoral bone defect model four weeks after the implantation of the fibroin porous scaffold. These results indicate the osteoconduction of the scaffolds.

On the basis of Förster resonance energy transfer (FRET) effect a method to analyze the structure of (Cy3, Cy5)-labeled nucleosomes in polyacrylamide gel after electrophoresis in native conditions was developed. It is shown that the correct application of the method requires monitoring of nonspecific intermolecular FRET and fluorescence re-absorption. A comparative analysis of the results of the FRET measurements of two types of nucleosomes and their complexes with yeast protein FACT was performed, which confirmed the similarity of the structural features of nucleosomes detected in the gel and in aqueous solution. An application of FRET analysis in combination with electrophoresis allows one to separate and visualize components of a complex mixture, evaluate their relative content, and, in addition, to characterize the structural differences between these complexes in situ.

Isolation and characterization of a new phenol- and 2,4-dichlorophenol (2,4-DCP)-degrading bacterium from the soil contaminated with phenol and its derivatives for a long time are reported. The strain 17S was identified as Rhodococcus erythropolis based on the results of 16S rRNA sequence analysis data and its phenotypic, physiological and biochemical features. The growth of R. erythropolis 17S in batch culture using phenol and 2,4-DCP as sources of carbon and energy has been studied. The concentration of phenol and 2,4-DCP in culture medium decreased by 55% (at the 4th day) and 47% (at the 22nd day) from the control values, respectively. It is concluded that R. erythropolis 17S can be used for phenol utilization in industrial wastewaters of petrochemical and tanning extracts manufacturing.

Micromycetes Aspergillus ustus 1 and Tolypocladium inflatum k1 were shown to produce proteolytic enzymes with high collagenolytic, fibrinolytic and elastolytic activity. The activity of the proteinases against fibrillar proteins was determined by the cleavage of azocollagen: collagenolytic activity was 122.6•10–3 EAzc/ml (EAzc – the amount of azocollagen cleaved in 1 min in micrograms) for proteinases produced by A. ustus 1 and 69.7•10–3 EAzc/ml for proteinases produced by T. inflatum k1. The maximum activity values were observed at submerged cultivation of A. ustus 1 during 4 days, and T. inflatum k1 during 5 days. It has been shown that the maximum of collagenolytic and general proteolytic activity during the cultivation of A. ustus 1 are time-separated, unlike T. inflatum k1. This fact, presumably, can simplify the procedure for obtaining of active proteinases.

Many bacterial secondary metabolites including pharmacologically promising compounds are synthesized by polyketide synthases (PKS) enzyme complexes. Nucleotide sequences of genes encoding 16S rRNA and PKS of heterotrophic bacterial strains isolated from epilithic biofilms in the littoral zone of Lake Baikal were determined. Based on molecular phylogenetic analysis of 16S rRNA genes, we identified six heterotrophic strains: Serratia fonticola 1А and 10А, Pseudomonas umsongensis K10-2 and K10-3, Rheinheimera tilapiae K18 and Flavobacterium sp. 43-09. Sequencing of cloned amplification products for PKS gene cluster revealed 33 sequences. Genes involved in biosynthesis of antibiotics (difficidine, erythromycin, curacin, mixalamide, corallopyronin, and myxothiazol) and cytostatics (romidepsin, spiruchostatin, and disorazol) were determined among related sequences. The low homology (50–83%) of amino acid sequences of PKS in Baikal bacteria with sequences in GenBank attests to potential capability of strains to produce new, yet not studied polyketide substances. The results obtained show that the strains under investigation may be of practical interest for biotechnological application.

Nhp6 is a small yeast protein, which binds DNA nonspecifically. It was shown that Nhp6 is a part of several protein complexes (including FACT complex) and is presented on many yeast promoters and transcribed regions of genes in vivo. It also participates in the process of destabilizing the structure of nucleosomes in vitro. In our laboratory, we studied FACT complex and showed its role in the transcription of eukaryotic RNA-polymerase 2 in vitro, but the role of the Nhp6 protein in transcription has not been studied previously. In this paper, we describe the effect of Nhp6 protein on transcription through a nucleosome by eukaryotic RNA-polymerase 2 and show that Nhp6 protein increases the transcription efficiency at several positions on the nucleosomal DNA, primarily the transcription at the positions +(11–17) in the nucleosome. We proposed a model of the action of Nhp6 during transcription through chromatin, suggesting the stabilization of DNA transiently uncoiled from the octamer during this process.

Ideas of proponents and opponents of the programmed aging concerning the feasibility of this phenomenon for the evolution of living organisms are shortly considered. We think that evolution has no “gerontological” purpose, because the obligate restriction of cell proliferation during the development of multicellular organisms is a factor that “automatically” launches aging due to the accumulation in the cells of various macromolecular lesions because of inhibition or even complete cessation of the appearance of new, intact cells. This leads to supression of “dilution” of stochastic damage (the most important of which are DNA lesions) at the level of the entire cellular population. Some additional arguments are also listed in favor of the inexpediency of aging for both species and indi vidual.

Some species of cyanobacteria synthesize toxins, whose concentration during water bloom can reach values dangerous to human and animal health. Planktonic cyanobacteria are the most common and well-studied producers of microcystins – hepatotoxic cyclic heptapeptides, whereas microcystin-producing benthic cyanobacteria are less known. In recent years, the mass development of benthic cyanobacteria forming extensive fouling on different substrates has been recorded in the littoral zone of Lake Baikal. We found microcystins produced by benthic cyanobacteria in the biofouling inhabiting different substrates, including diseased and dead endemic sponges Lubomirskia baicalensis and Baikalospongia spp., collected from the littoral area of Lake Baikal. Microscopic analysis of the biofouling revealed prevalence of Nostocales and Oscillatoriales cyanobacteria with the dominance of Tolypothrix distorta that is likely the main microcystin producer in Lake Baikal. According to enzyme-linked immunosorbent assay (ELISA), microcystin concentrations in biofouling were 29.8–3050 μg/kg dry weight. We identified eight microcystin variants using MALDI-TOF/TOF; [Dha7]MC-YR being recorded in most samples. The presence of microcystins in biofilms formed on the surface of the artificial substrate by Phormidium autumnale was also recorded. The data obtained show the necessity to monitor potentially toxic species and concentrations of cyanotoxins in plankton and benthos in the littoral zone of Lake Baikal, especially in the regions with intense tourist and recreational activities.