Diadenosine polyphosphates are now considered as a novel class of endogenous paracrine signal compounds. The putative role of these compounds in pathogenesis of myocardial infarction was proposed, since the concentration of diadenosine polyphosphates increases in the cardiac tissue following the ischemic lesion and myocardial necrosis. Therefore, possible effects of diadenosine polyphosphates on cardiac electrical activity and their ionic mechanisms are of considerable interest. In the present study we have investigated the effects of diadenosine pentaphosphate (Ap5A), diadenosine tetraphosphate (Ap4A) and NAD+ on transmembrae currents, belonging to the family of potassium inward rectifiers: background inward rectifier (IK1), ATP-dependent potassium current (IKATP) and acetylcholine-dependent current (IKACh). Experiments were performed using the whole-cell patch-clamp technique on isolated atrial and ventricular rat cardiomyocytes. We have demonstrated that none of tested adenine compounds affects IK1 and IKACh. Ap5A (10–5М) induces considerable decrease of both inward and outward component of IKATP by 22,1 and 19% of control value, respectively. Higher concentration of Ap5A (3×10–5М) produces stronger suppression of IKATP — by 47,5 and 37,8%, respectively. However, IKATP turned out to be insensitive to Ap4A and NAD+.

Social insects are promising model organisms in the study of the mechanisms determining longevity. They have the caste system in which the same genome may produce phenotypes significantly differing in longevity. In honeybee, caste differentiation depends on the duration of supply by specific nutrient mixture (royal jelly) on the larval stage. Longer feeding by the royal jelly leads to the formation of the queen epigenome which differs from the epigenome of worker bee. Such epigenetic differences, in turn, induce endocrine changes manifested in increased synthesis of juvenile hormone and activation of TOR signaling pathway, as well as in the modulation of insulin/IGF-1 pathway in queen-destined larvae. In adults, these processes influence the synthesis of vitellogenin (egg yolk precursor affecting many aspects of insect ontogenesis). Epigenetic and endocrine mechanisms that underlie differences in longevity among social insect castes are discussed.

The most popular biomarker of cellular senescence (BCS) is the activity of senescence-associated beta-galactosidase (SA-β-Gal). Today, this is the prevailing BCS in the studies based on a definition of cell senescence (which we do not accept) understood primarily as accumulation in the cells (most often — not prone to replicative senescence) of certain BCS under the impact of various external factors causing DNA damage. However, some papers provide evidence that SA-β-Gal activity in the cells is not so good a BCS, because it often depends not so much on age (in vitro or in vivo) as on the method of research, the presence of certain pathologies, and, what is most important, on the proliferative status of the cells studied. It appears that restriction of cell proliferation under certain conditions (due to differentiation, contact inhibition, DNA damage, some diseases, etc.) is itself the factor that stimulates SA-β-Gal expression. In other words, SA-β-Gal appears even in “young” cells if their proliferation is suppressed. Such data, in our opinion, appear to provide additional evidence for the validity of our concept of aging that postulates the leading role of cell proliferation restriction in the age-related accumulation of various macromolecular defects (primarily DNA damage) in the cells.

The review presents currently available data on the biological role of 8-oxo-2’-deoxyguanosine. This compound has been successfully and for a long time used as a biomarker of oxidative stress and diseases associated with it. However, in recent years an increasing number of publications has appeared reporting that 8-oxo-dG is not simply a byproduct of oxidation processes, but is of great biological importance. It is assumed that it is involved in the regulation of gene expression, in some processes of DNA repair, in the control of inflammatory and autoimmune reactions, and in the activation of antioxidant systems. Probably there is a prospect of applying 8-oxo-2’-deoxyguanosine as a drug.

The principles of nucleosome organization and formation were studied using molecular modeling approach. Nucleosomes are compact protein–DNA complexes that plays the key role in DNA compactization and regulation of gene transcription and expression. Nucleosome assembly and operation strongly depends on the ionic environment and electrical characteristics of the medium. The distribution of monovalent ions in the system was determined. The preferred locations of the ions were
identified. The distribution of electrostatic potential around nucleosome was investigated using a new method for averaging the distribution around macromolecule drifting in the volume of the computational cell.

Studying of plant virions and viral coat proteins structure, and also possibilities of their modification and structural remodeling are extremely important for development of absolutely new approaches to creation of biotechnological products, including health products. Plant viruses have clear advantage for obtaining new functional and biologically active materials, inter alia candidate vaccines, due to the fact that plant viruses are not pathogenic for mammals, including humans. The present review focuses attention on characteristic and applying in biotechnology of spherical particles (SP) — the new type platforms generated by structural remodeling of plant viruses. SPs have no structural analogs among the icosahedral viruses and represent the new type of biogenic platforms. Assembly of immunogenic complexes of SP-antigen in vitro opens perspectives of inexpensive and rapidly produced various vaccines.

Fluorescent in situ hybridization (FISH) and PCR were used for analysis of the phylogenetic structure of anaerobic sulfate-reducing bacterial communities in oxygen-containing upper water layers of meromictic basins — the Black Sea and the Gdańsk Deep of the Baltic Sea. In the Black Sea (continental slope at depths 30–70 m), cells of sulfate-reducing bacteria (SRB) hybridizing with 16S rRNAspecific FISH-probes for Desulfotomaculum, Desulfobacter and Desulfovibrio genera were revealed, whereas Desulfomicrobium-related bacteria were prevalent in the chemocline zone at 150-m depth. Besides of Desulfotomaculum (SRB subgroup 1), Desulfobacter (SRB subgroup 4) and Desulfovibrio-Desulfomicrobium (SRB subgroup 6), nested PCR with the use of 16S rRNA gene-specific primers detected the presence of Desulfococcus-Desulfonema-Desulfosarcina (SRB subgroup 5) in oxygen-containing water column of the Black and Baltic seas. Active enrichment SRB culture which contained bacterium Desulfosporosinus sp. as a major component was obtained from the Black Sea water sample collected at 70-m depth.

Fluorescence microscopy of single molecules and complexes is becoming increasingly popular method to study nucleosomes and functionally important processes with their participation. In this work we report on the development of positioned mononucleosomes on the basis of fluorescently labeled DNA matrix, which are a new tool for investigation of structural rearrangements in chromatin during transcription by RNA polymerase (RNAP). Two fluorophores, Cy3 (donor) and Cy5 (acceptor), were introduced in a non-transcribed DNA chain. After DNA packing on histone core they are positioned in the middle part of a nucleosome in the neighboring supercoils at a distance of less than 60 Å and interact by the mechanism of Förster resonance energy transfer (FRET). Changes in the nucleosome structure were monitored by changes in FRET efficiency in the study of single complexes of nucleosomes with RNAP by fluorescence microscopy. It is shown that introduction of labels did not affect the ability of RNAP to transcribe nucleosomes. Open complex with RNAP as well as elongation complexes stalled at positions –39 and –5 before the nucleosome boundary were prepared and characterized. It is shown that more than 80% of histones maintain their structure, restoring the original packing of DNA on the histone core after transcription completion. A new experimental system offers new possibilities for the study of a structure of nucleosomes and modulating effects of various protein chaperones
and remodelers on them.

The technique of spherical particles obtaining from rod-like plant virus — tobacco mosaic virus in preparative scale was developed. The conditions of tobacco mosaic virus isolation for spherical particles obtaining were selected. Spherical particles were examined by methods of electron microscopy, nanoparticle tracking analysis and dynamic light scattering. Information about inner structure of spherical particles was obtained. High electron density of spherical particles was demonstrated. The analysis of ultrathin sections showed that spherical particles are homogeneous within and do not contain any cavities.