Characterization of Bacillus strains of marine origin

A total of twenty aerobic endospore-forming bacilli, isolated from marine invertebrates and sea water of different areas of the Pacific Ocean, were taxonomically characterized. Most of the bacilli (11 strains) of marine origin belonged to the species Bacillus subtilis, according to their phenotypic characteristics, antibiotic susceptibility profiles, and fatty acids patterns. A group of four alkaliphilic strains formed a separate cluster that was tentatively classified as B. horti. One isolate, KMM 1717, associated with a sponge from the Coral Sea was identified as B. pumilus. Two strains, Bacillus KMM 1916 and KMM 1918, showed antibiotic sensitivity profiles similar to B. licheniformis, but they had a distinct fatty acid composition and peculiar phenotypic traits. The taxonomic affiliation of KMM 1810 and KMM 1763 remained unclear since their fatty acid composition and antibiotic sensitivity patterns were not resembled with none of these obtained for Bacillus strains

Factors influencing the prevalence of resistance-associated substitutions in NS5A protein in treatment-naive patients with chronic hepatitis C

Direct-acting antivirals (DAAs) revolutionized treatment of hepatitis C virus (HCV) infection. Resistance-associated substitutions (RASs) present at the baseline impair response to DAA due to rapid selection of resistant HCV strains. NS5A is indispensable target of the current DAA treatment regimens. We evaluated prevalence of RASs in NS5A in DAA-naïve patients infected with HCV 1a (n = 19), 1b (n = 93), and 3a (n = 90) before systematic DAA application in the territory of the Russian Federation. Total proportion of strains carrying at least one RAS constituted 35.1% (71/202). In HCV 1a we detected only M28V (57.9%) attributed to a founder effect. Common RASs in HCV 1b were R30Q (7.5%), L31M (5.4%), P58S (4.4%), and Y93H (5.4%); in HCV 3a, A30S (31.0%), A30K (5.7%), S62L (8.9%), and Y93H (2.2%). Prevalence of RASs in NS5A of HCV 1b and 3a was similar to that worldwide, including countries practicing massive DAA application, i.e., it was not related to treatment. NS5A with and without RASs exhibited different co-variance networks, which could be attributed to the necessity to preserve viral fitness. Majority of RASs were localized in polymorphic regions subjected to immune pressure, with selected substitutions allowing immune escape. Altogether, this explains high prevalence of RAS in NS5A and low barrier for their appearance in DAA-inexperienced population.Fil: Kyuregyan, Karen K.. Russian Academy Of Sciences; Rusia. Russian Medical Academy Of Continuous Professional Education; Rusia. I. I. Mechnikov Research Institute For Vaccines And Sera; RusiaFil: Kichatova, Vera S.. Russian Medical Academy Of Continuous Professional Education; Rusia. Russian Academy Of Sciences; Rusia. I. I. Mechnikov Research Institute For Vaccines And Sera; RusiaFil: Karlsen, Anastasiya A.. I. I. Mechnikov Research Institute For Vaccines And Sera; Rusia. Russian Medical Academy Of Continuous Professional Education; Rusia. Russian Academy Of Sciences; RusiaFil: Isaeva, Olga V.. I. I. Mechnikov Research Institute For Vaccines And Sera; Rusia. Russian Medical Academy Of Continuous Professional Education; RusiaFil: Solonin, Sergei A.. N.V. Sklifosovsky Research Institute for Emergency Medicine; RusiaFil: Petkov, Stefan. Karolinska Huddinge Hospital. Karolinska Institutet; SueciaFil: Nielsen, Morten. Technical University of Denmark; Dinamarca. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; ArgentinaFil: Isaguliants, Maria G.. Russian Academy Of Sciences; Rusia. Karolinska Huddinge Hospital. Karolinska Institutet; SueciaFil: Mikhailov, Mikhail I.. Russian Medical Academy Of Continuous Professional Education; Rusia. I. I. Mechnikov Research Institute For Vaccines And Sera; Rusi

Detection of antibodies to the hepatitis E virus in domestic reindeer (<i>Rangifer tarandus</i>) in the Republic of Sakha (Yakutia)

Introduction. Although domestic pigs and wild boars are the main reservoir of zoonotic hepatitis E virus (HEV) genotypes in temperate countries, the presence of antibodies to HEV (anti-HEV) in the indigenous population of circumpolar territories, i.e. outside the habitat of wild and domestic pigs, indicates the presence of an alternative reservoir of the virus. Reindeer (Rangifer tarandus) may be a potential reservoir for HEV in the polar regions. The purpose of the study was to determine the prevalence of anti-HEV among domestic reindeer in the Republic of Sakha (Yakutia). Materials and methods. Sera from 497 domestic reindeer from the Oymyakon (n = 425) and Ust-Yansky districts (n = 72) of the Republic of Sakha (Yakutia) were tested for anti-HEV. A commercial ELISA kit DS-ELISA-ANTI-HEV-G (Diagnostic Systems-Stolitsa LLC, Russia) was used for detection of anti-HEV IgG, but a rabbit polyclonal antibody against deer IgG labeled with horseradish peroxidase (KPL, USA) at a dilution of 1 : 100 in phosphate-buffered saline were used instead of the human specific conjugate from the kit. Results. The average detection rate of anti-HEV in reindeer sera was 15.5% (95% CI: 12.6–19.0%). The detection rate of anti-HEV significantly increased with age, from 3.5% (95% CI: 1.1–9.0%) in calves aged 3–6 months to 25.0% (95% CI: 1.6 –36.5%) in deer aged 2–4 years (p 0.0001). From this age group, anti-HEV detection rates reached a plateau, not differing significantly between older age groups (p 0.05). The average anti-HEV detection rate among reindeer 2 years of age and older was 19.0% (95% CI: 15.3–23.4%). There were no statistically significant differences in the frequency of anti-HEV detection between female and male reindeer, both among adult animals and among calves. Conclusion. The observed anti-HEV detection rates among domestic reindeer in the Republic of Sakha (Yakutia) indicate that infection caused by HEV or an antigenically similar virus is common in these animals. The dynamics of antibody accumulation in the reindeer population indicates that infection apparently occurs during the first two years of life

Molecular epidemiological study of clinical cases of acute hepatitis E in Belarus

Relevance. The frequency of occurrence of anamnestic antibodies to the hepatitis E virus (HEV) in the general population of the Republic of Belarus is 7.3%, which is clearly not consistent with the low incidence of hepatitis E (HE). Most of primary HEV infections remain undiagnosed. The intensive epidemic process of HEV in the Belarusian population is hidden. Conducting epidemiological studies, including genotyping of HEV sequences isolated on the territory of the republic, makes it possible to more accurately characterize the sources of HEV infection and the mechanisms of its transmission. Aim molecular epidemiological study of two cases of acute hepatitis E detected in patients from Belarus. Materials and methods. During 20212022, samples of biological material were obtained from two patients undergoing treatment with an established diagnosis of acute hepatitis E. Serum samples were tested to detect antibodies to HEV using enzyme immunoassay, HEV RNA was detected in fecal samples using nested RT-PCR. The nucleotide sequence was determined by an automatic sequencer using the Sanger method. Analysis of nucleotide sequences, their genotyping, and calculation of evolutionary distances were performed using MEGA X software. Results. The HEV sequence isolated from a pregnant woman who had an epidemiological episode of alimentary contact with raw pork meat is clustered into a common phylogenetic clade with HEV sequence obtained from the patient from Belarus with a history of kidney transplantation and HEV sequences isolated from a domestic pigs. The HEV sequence isolated from a patient with a history of travel to Pakistan belongs to the HEV genotype 1 and joins a clade of HEV sequences isolated in Pakistan, India, Nepal and Mongolia

Coverage with timely administered vaccination against hepatitis b virus and its influence on the prevalence of HBV infection in the regions of different endemicity

Funding Information: Funding: This research was funded by grant of the Russian Science Foundation (ID-20-15-00148). Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Universal hepatitis B vaccination of newborns was implemented in Russia starting from 1998. From 1998 to 2019, the incidence of acute hepatitis B reduced from 43.8 to 0.57 cases per 100,000 population. Here, we assessed the timely coverage of newborns with the birth dose (HepB-BD), second dose (HepB-2nd), and three vaccine doses (HepB3) in two remote regions of Russia with low (Belgorod Oblast) and high (Yakutia) levels of hepatitis B virus (HBV) endemicity. Vaccination data were obtained from the medical records of 1000 children in Yakutia and 2182 children in Belgorod Oblast. Sera of healthy volunteers from Belgorod Oblast (n = 1754) and Yakutia (n = 1072) across all age groups were tested for serological markers of HBV to assess the infection prevalence and herd immunity. Average HepB-BD coverage was 99.2% in Yakutia and 89.4% in Belgorod Oblast (p < 0.0001) and in both regions varied significantly, from 66% to 100%, between medical centers. The principal reason for the absence of HepB-BD was parent refusal, which accounted for 63.5% of cases of non-vaccination (83/123). While timely HepB-2nd coverage was only 55.4%–64.7%: HepB3 coverage by the age of one year exceeded 90% in both study regions. HBV surface antigen (HBsAg) prevalence in the 1998–2019 birth cohort was 0.2% (95% CI: 0.01–1.3%) in Belgorod Oblast and 3.2% (95% CI: 1.9–5.2%) in Yakutia. The proportion of persons testing negative for both antibodies to HBsAg (anti-HBs) and antibodies to HBV core antigen (anti-HBc) in the 1998–2019 birth cohort was 26.2% (125/481) in Belgorod Oblast and 32.3% (162/501) in Yakutia. We also assessed the knowledge of and attitude towards vaccination among 782 students and teachers of both medical and non-medical specialties from Belgorod State University. Only 60% of medical students knew that hepatitis B is a vaccine-preventable disease. Both medical and nonmedical students, 37.8% and 31.3%, respectively, expressed concerns about safety and actual necessity of vaccination. These data indicate the need to introduce a vaccine delivery audit system, improve medical education with respect to vaccination strategies and policies, and reinforce public knowledge on the benefits of vaccination.Peer reviewe

On Propagation of Excitation Waves in Moving Media: The FitzHugh-Nagumo Model

BACKGROUND: Existence of flows and convection is an essential and integral feature of many excitable media with wave propagation modes, such as blood coagulation or bioreactors. METHODS/RESULTS: Here, propagation of two-dimensional waves is studied in parabolic channel flow of excitable medium of the FitzHugh-Nagumo type. Even if the stream velocity is hundreds of times higher that the wave velocity in motionless medium (), steady propagation of an excitation wave is eventually established. At high stream velocities, the wave does not span the channel from wall to wall, forming isolated excited regions, which we called "restrictons". They are especially easy to observe when the model parameters are close to critical ones, at which waves disappear in still medium. In the subcritical region of parameters, a sufficiently fast stream can result in the survival of excitation moving, as a rule, in the form of "restrictons". For downstream excitation waves, the axial portion of the channel is the most important one in determining their behavior. For upstream waves, the most important region of the channel is the near-wall boundary layers. The roles of transversal diffusion, and of approximate similarity with respect to stream velocity are discussed. CONCLUSIONS: These findings clarify mechanisms of wave propagation and survival in flow

Climate shapes the spatiotemporal variation in color morph diversity and composition across the distribution range of Chrysomela lapponica leaf beetle

Color polymorphism offers rich opportunities for studying the eco-evolutionary mechanisms that drive the adaptations of local populations to heterogeneous and changing environments. We explored the color morph diversity and composition in a Chrysomela lapponica leaf beetle across its entire distribution range to test the hypothesis that environmental and climatic variables shape spatiotemporal variation in the phenotypic structure of a polymorphic species. We obtained information on 13 617 specimens of this beetle from museums, private collections, and websites. These specimens (collected from 1830-2020) originated from 959 localities spanning 33 degrees latitude, 178 degrees longitude, and 4200 m altitude. We classified the beetles into five color morphs and searched for environmental factors that could explain the variation in the level of polymorphism (quantified by the Shannon diversity index) and in the relative frequencies of individual color morphs. The highest level of polymorphism was found at high latitudes and altitudes. The color morphs differed in their climatic requirements; composition of colour morphs was independent of the geographic distance that separated populations but changed with collection year, longitude, mean July temperature and between-year temperature fluctuations. The proportion of melanic beetles, in line with the thermal melanism hypothesis, increased with increasing latitude and altitude and decreased with increasing climate seasonality. Melanic morph frequencies also declined during the past century, but only at high latitudes and altitudes where recent climate warming was especially strong. The observed patterns suggest that color polymorphism is especially advantageous for populations inhabiting unpredictable environments, presumably due to the different climatic requirements of coexisting color morphs

Photodisintegration of 4^4He into p+t

The two-body photodisintegration of $^4$He into a proton and a triton has been studied using the CEBAF Large-Acceptance Spectrometer (CLAS) at Jefferson Laboratory. Real photons produced with the Hall-B bremsstrahlung-tagging system in the energy range from 0.35 to 1.55 GeV were incident on a liquid $^4$He target. This is the first measurement of the photodisintegration of $^4$He above 0.4 GeV. The differential cross sections for the $\gamma$$^4$He$\to pt$ reaction have been measured as a function of photon-beam energy and proton-scattering angle, and are compared with the latest model calculations by J.-M. Laget. At 0.6-1.2 GeV, our data are in good agreement only with the calculations that include three-body mechanisms, thus confirming their importance. These results reinforce the conclusion of our previous study of the three-body breakup of $^3$He that demonstrated the great importance of three-body mechanisms in the energy region 0.5-0.8 GeV .Comment: 13 pages submitted in one tgz file containing 2 tex file and 22 postscrip figure

Climate shapes the spatiotemporal variation in color morph diversity and composition across the distribution range of Chrysomela lapponica leaf beetle

Color polymorphism offers rich opportunities for studying the eco-evolutionary mechanisms that drive the adaptations of local populations to heterogeneous and changing environments. We explored the color morph diversity and composition in a Chrysomela lapponica leaf beetle across its entire distribution range to test the hypothesis that environmental and climatic variables shape spatiotemporal variation in the phenotypic structure of a polymorphic species. We obtained information on 13 617 specimens of this beetle from museums, private collections, and websites. These specimens (collected from 1830-2020) originated from 959 localities spanning 33 degrees latitude, 178 degrees longitude, and 4200 m altitude. We classified the beetles into five color morphs and searched for environmental factors that could explain the variation in the level of polymorphism (quantified by the Shannon diversity index) and in the relative frequencies of individual color morphs. The highest level of polymorphism was found at high latitudes and altitudes. The color morphs differed in their climatic requirements; composition of colour morphs was independent of the geographic distance that separated populations but changed with collection year, longitude, mean July temperature and between-year temperature fluctuations. The proportion of melanic beetles, in line with the thermal melanism hypothesis, increased with increasing latitude and altitude and decreased with increasing climate seasonality. Melanic morph frequencies also declined during the past century, but only at high latitudes and altitudes where recent climate warming was especially strong. The observed patterns suggest that color polymorphism is especially advantageous for populations inhabiting unpredictable environments, presumably due to the different climatic requirements of coexisting color morphs

Directed emission of CdSe nanoplatelets originating from strongly anisotropic 2D electronic structure

ntrinsically directional light emitters are potentially important for applications in photonics including lasing and energy-efficient display technology. Here, we propose a new route to overcome intrinsic efficiency limitations in light-emitting devices by studying a CdSe nanoplatelets monolayer that exhibits strongly anisotropic, directed photoluminescence. Analysis of the two-dimensional k-space distribution reveals the underlying internal transition dipole distribution. The observed directed emission is related to the anisotropy of the electronic Bloch states governing the exciton transition dipole moment and forming a bright plane. The strongly directed emission perpendicular to the platelet is further enhanced by the optical local density of states and local fields. In contrast to the emission directionality, the off-resonant absorption into the energetically higher 2D-continuum of states is isotropic. These contrasting optical properties make the oriented CdSe nanoplatelets, or superstructures of parallel-oriented platelets, an interesting and potentially useful class of semiconductor-based emitters