[Lethal cases of lyssavirus encephalitis in humans after contact with bats in the Russian Far East in 2019-2021].

INTRODUCTION: On the territory of Russia four species of lyssaviruses (genus Lyssavirus) were identified, three of them caused human deaths. THE AIM OF WORK: to characterize fatal cases in humans after contacts with bats in the Far East in 20182021 and to perform typing of isolated pathogens. MATERIALS AND METHODS: Lyssavirus infection was confirmed in samples of sectional material from people who died in the Amur Region in 2019, in the Primorsky Krai in 2019 and 2021. Diagnostics was performed by fluorescent antibody test (FAT) and RT-PCR using diagnostic kits of domestic production. Viruses were isolated in a bioassay. The nucleoprotein sequences were analyzed after 1st passage. The analysis of phylogenetic relationships and the construction of a dendrogram were performed using the MEGA7 software. RESULTS: The viruses that caused the fatal cases in humans in the Amur Region and Primorsky Krai share more than 90% identity to Lyssavirus irkut detected in Russia and China. Together they form a separate monophyletic cluster with 100% bootstrap support. CONCLUSION: On the territory of Russia, monitoring of bat populations for infection with lyssaviruses is relevant. The material of people who died from encephalomyelitis of unknown etiology within 1015 days from the onset of the disease must be examined for lyssavirus infection. It is necessary to develop PCR assays that employ genus-specific primers. The use of molecular biological methods is promising for improving the diagnosis of rabies and epidemiological surveillance, as well as increasing the efficiency of the system of biological safety of the population of the Russian Federation.

Optical nonlinearity of a dual-frequency nematic liquid crystal via temperature-mediated mapping of dielectric anisotropy.

Liquid crystals are of great interest in the field of nonlinear optics due to their efficient response to low intensity light fields. Here we present a new, to the best of our knowledge, mechanism of a nonlinear optical response which is observed for a dye-doped dual-frequency nematic liquid crystal. The local increase in temperature caused by the absorption of light beam in the liquid crystal medium leads to spatial variation and inversion of the sign of the dielectric anisotropy. When an alternating current electric field with a frequency close to the cross-over frequency is applied to the liquid crystal cell, the planar orientation sustains at the beam periphery, but elastic deformation occurs in the irradiation region. In the case of a dye dopant with negative absorption dichroism, a first-order orientational transition with large bistability region is obtained.

[MEDICAL AND LEGAL ASPECTS IN PROOF OF RAPES].

The purpose of the study is to analyze new edition of the article 152 of the Criminal Code of Ukraine «Rape¼, which was adopted with the aim of implementing the Council of Europe Convention on preventing and combating violence against women and domestic violence. The analysis was carried out in terms of the possibility of implementing legal definitions in evidence, taking into account the fundamental medical scientific provisions related to sexual relations. The authors, taking into account the study of more than 100 sentences handed down by the courts of Ukraine in 2010-2018 in criminal cases of rape from the point of view of using medical knowledge in evidence, found a significant change in the objective side of rape, which affected the subject of evidence in criminal proceedings. Now rape is defined as committing acts of a sexual nature associated with vaginal, anal or oral penetration into the body of another person using the genitals or any other object, without the voluntary consent of the victim. A significant change in the rape modus operandi leads to a number of problematic issues in the practical application of these provisions by law enforcement agencies and courts. These issues can be solved, according to the authors' opinion, only by taking into consideration medical and legal aspects of rape. The medical aspect of rape is very important because the concept of rape is legal, but its interpretation is based on the use of medical concepts. The concept of "committing acts of a sexual nature associated with vaginal, anal or oral penetration into the body of another person using the genitals or any other object" is analyzed taking into account the existing and well-established in Forensic Medicine notions of sexual intercourse. The legal aspect of rape is not only to give a legal interpretation of the medical facts of committing sexual acts, but also to establish the absence of the voluntary consent of the victim. The problem of false statements about rape is analyzed, possible indicators of such statements are identified. This problem is quite topical in many countries with a similar interpretation of rape. It is concluded that the medical and legal aspects of rape are closely interrelated, since mechanism of this crime is based on physiological sexual act that is subject to legal assessment.

Quantification of the diagenesis-designating metals in sediments by ICP-MS: Comparison of different sample preparation methods.

Concentrations of specific metals in sediments are of immense importance in geochemical studies related to diagenetic processes, and quantification can be most reliably performed by ICP-MS after bringing the sample into solution. It is the latter analytical operation that generates a discord as no common sample preparation approach has been yet accepted. To resolve this challenge, we compared different modes of acidic sample digestion (in open and closed systems, applying in the latter case conventional or microwave heating) using a lake sediment reference sample. It was shown that the sample treatment in an autoclave with resistance heating provides the best fit (relative deviation < 7%) to certified values for metals generally used as diagenetic proxies (U, Sm, Nd, Th, La, Sc, Sr, etc.). Furthermore, the thermally convective pressure digestion appears to be more cost-efficient than microwave-assisted digestion (because of lower reagent consumption and cheaper removable PFE liners), an important asset for systematic geochemical mapping. In order to prove the applicability of the developed digestion procedure for different sediments, a marine sample from the East Siberian Sea was analyzed independently in two laboratories and across all representative metals the results acquired were found in good agreement.

Effects of carbon and silicon nanotubes and carbon nanofibers on marine microalgae Heterosigma akashiwo.

The effect of carbon and silicon nanotubes (CNTs and SiNTs) and carbon nanofibers (CNFs) to microscopic marine algae Heterosigma akashiwo was studied, using algal growth inhibition for 3 days (acute effect) and 7 days (chronic effect) as toxicity endpoints. The criterion of the toxic effect was the statistically significant reduction of the number of algal cells in the exposed samples compared to the control. Samples did not demonstrate toxic effects at doses 1 mg/l and 10 mg/l. CNTs and SiNTs samples at 100 mg/l exhibited both acute and chronic toxic effects. We assume that the main cause of cell death in these samples was related to the mechanical damage of cell integrity. CNFs at concentrations of 100 mg/l did not inhibit algal growth, but cells with irregular shapes were observed, which were not observed after exposure to CNTs and SiNTs. Nickel impurities present in CNFs samples are presumably the main cause of observed cell deformations.

One-stage immobilization of the microalga Porphyridium purpureum using a biocompatible silica precursor and study of the fluorescence of its pigments.

The biocompatible silica precursor tetrakis(2-hydroxyethyl)orthosilicate with ethylene glycol residues was used instead of the common alcohol-containing tetraethoxysilane for the first time to prepare a biorecognition element by entrapping the marine microalga Porphyridium purpureum into a silica matrix by a one-stage sol-gel procedure at conditions (pH, ionic strength, and temperature) appropriate for living cells. We show that the microalga immobilized in this way fully maintains its viability and functionality. We furthermore show that the silica matrix had a stabilizing effect, providing microalgal survival and functionality at increased temperature. The high optical transparency of the silica matrix allowed us to study the optical properties of Porphyridium purpureum thoroughly. When irradiated by a laser, intense fluorescence of chlorophyll-a and phycoerythrin of the photosynthetic system was observed. The characteristics of this fluorescence differed notably from that observed with P. purpureum in suspension before immobilization; possible reasons for this and an underlying mechanism are discussed.

Secondary Metabolites from Marine Microorganisms. II. Marine Fungi and Their Habitats.

Marine-derived fungi are of great interest as a new promising source of biologically active products such as anticancer compounds, antibiotics, inhibitors of biochemical processes. Since marine organisms inhabit biologically competitive environment with unique conditions, the chemical diversity of the secondary metabolites from marine fungi is considerably high. Recent genomic studies demonstrated that fungi can carry gene clasters encoding production of previously unknown secondary metabolites. Activation of the attenuated or silent genes would be useful either for improving activities of the known compounds or for discovery of new products.

Distribution of DTX-3 in edible and non-edible parts of Crenomytilus grayanus from the Sea of Japan.

Seasonal dynamics and the distribution of dinophysistoxin-3 (DTX-3) in organs of mussel Crenomytilus grayanus, collected in 2013 in Peter the Great Bay, Sea of Japan, were determined. Active toxin forms (OA, DTX-1/2) concentrated in digestive glands (60-80%), whereas non-active 7-O-acyl derivatives (DTX-3) were more abundant in edible soft tissues (more than 80%). Possible mechanism of fast removing of DTX-3 from the digestive gland and accumulation of DTX-3 in the soft tissues is supposed.

[Secondary Metabolites from Marine Microorganisms. I. Secondary Metabolites from Marine Actinomycetes].

Review represents data on new active metabolites isolated from marine actinomycetes published in 2007 to 2014. Marine actinomycetes are an unlimited source of novel secondary metabolites with various biological activities. Among them there are antibiotics, anticancer compounds, inhibitors of biochemical processes.

[Microbial secondary metabolites as potential reserve of pharmaceuticals].

The major characteristics of new bioactive microbial secondary metabolites are summarized in the review. A wide range of new molecular targets are implicated in discovery of new nonantibiotic compounds with some other pharmacological activities (noninfectious diseases). Microorganisms represent fascinating resources due to their production of novel products with broad spectra of bioactivities.

[Action of antibiotics as signalling molecules].

It was thought that antibiotics should be produced by soil microorganisms to inhibit the growth of competitors in natural habitats. Yet it has been shown that antibiotics at subinhibitory concentrations may have a role as signalling molecules providing cell-to-cell communication in bacteria in the environment. Antibiotics modulate gene transcription and regulate gene expression in microbial populations. Subinhibitory concentrations of antibiotics may cause a number of phenotypic and genotypic changes in microorganisms. These transcription changes are dependent on the interaction of antibiotics with macromolecular receptors such as ribosome or RNA-polymerase. Antibiotic signalling and quorum-sensing system are important regulatory mechanisms in bacteria. It was demonstrated that antibiotics interfered with quorum-sensing system.

[The phosphorylation state of transducin beta-subunits].

The supposition that nucleoside diphosphate kinase is the enzyme that phosphorylates transducin beta-subunits on one of the histidine residues (His-266) has been analyzed. It stands the reason that 1) this enzyme is multifunctional and plays in particular the role of protein histidine kinase; and 2) the phosphorylated beta-subunit of transducin may activate transducin via the mechanism of transphosphorylation. Nevertheless, in our experiments, in which different forms of transducin preparations were incubated with α- and ß-isoforms of recombinant rat NDP kinase in the presence of [γ32P]ATP or [γ32P]GTP (specific activity of about 1 Ci/mmol) followed by separation of proteins by electrophoresis and-gel radio-autography, the phosphorylation of the transducin beta-subunit wasn't succeeded to be found. The negative result of our experiments most likely implies that the major part of transducin beta-subunits in the preparations has already been phosphorylated via a process that takes place in vivo.

[Activation of bovine retinal rod outer segment cGMP-specific phosphodiesterase by the transducin-GTP complex in a physiologically significant range of free calcium ion concentrations].

The kinetic behavior of cGMP-specific phosphodiesterase in a totally bleached bovine retinal rod outer segment suspension was studied by the pH-metric method at high and low concentrations of free calcium ions (≈ 100 µM and 10 nM, respectively). The phosphodiesterase was activated by low GTP concentrations (about 1-2 µM) that were comparable with the concentration of G-protein transducin, its GTP-binding alpha-subunit was the intrinsic activator of photoreceptor phosphodiesterase. The results allow the suggestion that besides the earlier described system of RGS proteins, participating in the acceleration of GTP hydrolysis, rod outer segments also contain an additional Ca(2+)-dependent mechanism to inactivate so called "free transducin", i.e. active transducin that has not managed to interact with phosphodiesterase during the time, restricted by duration of photoreceptor response.

[Involvement of cyclic adenosine monophosphate in the control of motile behavior of Physarum polycephalum plasmodium].

Possible involvement of autocrine factors into the control of motile behavior via a receptor-mediated mechanism was investigated in Physarum polycephalum plasmodium, a multinuclear amoeboid cell with the auto-oscillatory mode of motility. Cyclic adenosine monophosphate (cAMP) and extracellular cAMP-specific phosphodiesterase, its involvement into the control of plasmodium motile behavior was proved by action of its strong inhibitor, were regarded as putative autocrine factors. It was shown that the plasmodium secreted cAMP. When it was introduced into agar support, 0,1-1 mM cAMP induced a delay of the plasmodium spreading and its transition to migration. When locally applied, cAMP at the same concentrations induced typical for attractant action the increase in oscillation frequency and the decrease of ectoplasm elasticity. The ability to exhibit positive chemotaxis in cAMP gradient and the dependence of its realization were shown to depend on the plasmodium state. Chemotaxis test specimens obtained from the migrating plasmodium, unlike those obtained from growing culture, generate alternative fronts which compete effectively with fronts oriented towards the attractant increment. The results obtained support our supposition stated earlier that advance of the Physarum polycephalum plasmodium leading edge is determined by local extracellular cAMP gradients arising from a time delay between secretion and hydrolysis of the nucleotide.

[Biologically active nonribosomal peptides. III. Mechanism of biosynthesis of nonribosomal peptides].

The third part of the review is concerned with investigation of nonribosomal peptides.

[Biologically active nonribosomal peptides. I. Nonribosamal polypeptide antibiotics].

The data on novel polypeptide antibiotics described within the last 10-15 years, as well as new researches on the known antibiotics with respect to their mechanisms of action and microbial resistance are presented.

[Dynamics of characteristics of the immune, cardiovascular, and autonomic nervous systems during aerocryotherapy in patients with different "immune health" status].

This study has demonstrated that subjects of different "immune health" status also differ in the activity of the vegetative nervous system. Aerocryotherapy was shown to have stimulatory effect on the immune system and decreased the hyperactivity of the parasympathetic nervous system especially in people suffering immune insufficiency.