4,811 research outputs found

    Methodology for assessing the agroecological adaptability of genotypes under global climate warming

    Get PDF
    Background. The relevance of the research is due to the fact that, despite the breeding achievements in releasing cultivars with high potential yield and resistance to the most common stressors in the regions, it is almost impossible to foresee and accurately predict the reaction of cultivars under production conditions. Besides, extreme weather events, including heat waves, droughts and downpours, will increasingly manifest themselves under global climate warming. To reduce the risk of a significant decrease in gross grain harvests in dry years and achieve high results under favorable conditions, the goal was to develop a comprehensive indicator for assessing the agroecological adaptability of genotypes to some consequences of global climate warming.Materials and methods. The results of a competitive test of 5 cultivars and 9 promising lines of spring wheat for their yield across six years contrasting in moisture availability by calculating the indicators of responsiveness to favorable conditions, grain yield depression under unfavorable conditions and the relative yield index were used to develop a complex indicator proposed to assess the agroecological adaptability of a genotype to contrasting environmental conditions.Results. The proposed method makes it possible to perform a comprehensive assessment that takes into account the responsiveness of an accession to improved agroclimatic conditions and the degree of its reaction to adverse environmental factors, taking into account the yield index in the studied set. The method is recommended for evaluating the source material and identifying the diversity of its responses to changes in agroclimatic conditions as well as for the stage of competitive variety testing in plant breeding for adaptability

    Dissemination of Influenza A/H5N1 Virus after Intranasal Inoculation of Chickens

    Get PDF
    Studied was dissemination of avian influenza virus (AIV) in the organism of chickens after intranasal challenge with 10-100 LD50. The primary organ of accumulation of AIV A/H5N1 (A/Chicken/Kurgan/05/2005strain) is the respiratory tract (nasal mucosa), where the virus is registered in 18 hours after challenge. The accumulation of pathogen is observed in many organs and serum of chicken in 30-32 hours after challenge. The animals die in 54 hours, the concentration of virus reaches critical value in all studied samples. The highest AIV loads (7 lg of chicken embryo infective dose - EID50/g or ml) are registered in lungs, blood serum and kidneys of chicken. The results of AIV loads measuring using titration and real time RT-PCR show high degree of correlation (r=0.89)

    Studies of Sensitivity to Avian Flu Virus A/H5N1 in Chickens

    Get PDF
    ) appear to be highly virulent for chickens. The chance of AFV infection of chickens in case of intranasal challenge is 20 times as great as in the case of peroral one, and 300 times as great as in the case of intragastral one, which bears evidence to higher sensitivity to AFV of the tissues of avian respiratory organs, in comparison with the tissues of gastro-intestinal tract. Therewith, primary target organ for virus in intranasal infected birds is their respiratory channel (mucous membrane of the nasal cavity in particular). Registered is the possibility of existence of fecal-nasal AFV transfer mechanism in chickens

    The distribution of tick-borne encephalitis virus genotypes in different types of landscapes of Eastern Siberia

    Get PDF
    To find out what is the role of some environmental factors in the formation of a heterogeneous viral population, the analysis of the distribution of tick-borne encephalitis virus (TBEV) genotypes in different types of landscapes of Eastern Siberia has been carried out. In our study, it was shown that TBEV area in all investigated landscapes of Eastern Siberia is represented not only by TBEV of genotype 3, absolute dominance of which is noted in the studied regions, regardless the landscapes where the foci are located, but also by strains of other genotypes. The relationship between genotypes 1,3 and "polytypic" strains with a certain type of landscape and the degree of their development by man has not been established. The prevailing number of strains of TBEV genotype 5 is isolated from the material collected in the Transbaikalia, in the landscapes of the mountain taiga. They, as well as the strain of genotype 4, are found in the foci, where joint circulation of several TBEV genotypes is noted. The strains of TBEV genotype 2 were revealed in the landscapes of plains and plateaus taiga and insular steppes and forest steppes of the southern part of the Baikal region. Moreover, the detection of RNA of TBEV genotype 2 in the "polytipic" 763-87 and 765-87 strains isolated in the floodplain and forest-steppe landscapes of the Barguzin hollow does not exclude the possibility of circulation of TBEV genotype 2 in the Transbaikalian foci. The greatest genetic heterogeneity of TBEV is observed in natural foci located along Lake Baikal and in the southeastern part of Transbaikalia

    Development of DNA-Biochip for Identification of Influenza A Virus Subtypes

    Get PDF
    Developed was the DNA-biochip to identify subtypes of influenza A virus, pathogenic for humans. Microchip was capable of detecting H1, H3, H5-subtypes of hemagglutinin (including H1-subtype of pandemic A/H1N1(2009) influenza virus ) and neuraminidase subtypes N1,N2 of influenza virus. This microchip was successfully tested on the strains of A/H5N1 highly pathogenic avian influenza virus, A/H1N1(2009) pandemic influenza virus, A/H1N1 and A/H3N2 seasonal influenza viruses

    Characteristics of genetic and phenotypic properties of tick-borne encephalitis virus strains isolated from various source on the territory of Eastern Siberia

    Get PDF
    Since ixodid ticks and their feeders (vertebrates) form the basis of the tick-borne encephalitis virus (TBEV) population, it was interesting to obtain a genetic characteristic of strains isolated from various sources in the territory of Eastern Siberia. In our study, it was found that the circulation of TBEV of genotypes 1, 2, 3, 5 and "polytypic" strains in the territory of Eastern Siberia is maintained both by the main vectors (I. persulcatus ticks) and by their feeders (small and large mammals, birds). The distribution of genotypes in strains groups from ixodid ticks and vertebrates varied. TBEV strains of genotypes 1 and 2 were significantly more often isolated from rodents, and genotype 3 from ixodid ticks (p < 0.05). Isolates of genotype 3 (85.5 %) prevailed in the group of strains isolated from ixodid ticks, of which 29.6 % belonged to "Vasilchenko", and 25.6 % to "Zausaev"subgenotypes. Genotypes 1 and 2 were represented by single isolates (3.3 % and 1.3 %, respectively). Among strains isolated from warm-blooded hosts, the proportion of genotype 1 was 35.3 %, genotype 2 -11.8 %, genotype 3 - 35.3 %. More than half of genotype 3 strains (58.3 %) were related to "Vasilchenko" subgenotype, and the strains of "Zausaev" subgenotype were not detected. The obtained data suggest that ixodid ticks and warm-blooded animals are amplifiers of TBEV of genotypes 3 and 1, respectively. The certain differences in the phenotypic characteristics of strains isolated from ticks and warm-blooded animals have been revealed. It has been found that strains isolated from ticks are more homogeneous in their antigenic characteristics, less heterogeneous in S-feature than strains isolated from warm-blooded sources. The strains isolated from warm-blooded animals demonstrate somewhat greater resistance to warming but reducing the reproduction of the virus at 42 °C, and have greater virulence compared to strains isolated from ticks

    Peculiarities of the Epidemic Situation on West Nile Fever in the Territory of the Russian Federation in 2018 and Forecast of its Development in 2019

    Get PDF
    The epidemic rise in the incidence of West Nile fever (WNF) in the season of 2018 was observed in the countries of the European Union (EU) and bordering states and exceeded the values of all previously recorded epidemic rises of 2010–2012. An increase in the incidence rate was registered in the USA and Canada, however, it did not exceed the indicators of epidemic rises of 2007–2012. In the territory of the Russian Federation, the WNF epidemiological process became more intense mainly in the territory of the Southern and North Caucasian Federal Districts. In general, in Russia, the incidence rates were 2 times lower than the average annual rates, but significantly exceeded those of 2017. The epidemic process had a number of peculiarities in the seasonality, the structure of morbidity and the clinical manifestation of WNF. Genotyping of the isolated WNV RNA fragments from clinical and biological material showed that I, II and IV West Nile virus genotypes were circulating in the European part of Russia. Forecast of epidemic situation development in 2019 reveals further increase in the incidence and does not exclude the possibility of a significant localincrease of WNF incidence in certain regions of Russia

    Search for Large Extra Dimensions in Dielectron and Diphoton Production

    Get PDF
    We report a search for effects of large extra spatial dimensions in ppbar collisions at a center-of-mass energy of 1.8 TeV with the DZero detector, using events containing a pair of electrons or photons. The data are in good agreement with the expected background and do not exhibit evidence for large extra dimensions. We set the most restrictive lower limits to date, at the 95% confidence level, on the effective Planck scale between 1.0 TeV and 1.4 TeV for several formalisms and numbers of extra dimensions.Comment: 6 pages, 2 figures, submitted to Phys. Rev. Let

    CHARACTERISTICS OF THE BAIKAL SUBTYPE OF TICK-BORNE ENCEPHALITIS VIRUS CIRCULATING IN EASTERN SIBERIA

    Get PDF
    Background. During the study of the genetic variability of the tick-borne encephalitis virus (TBEV) in Eastern Siberia, a group of 22  strains with a unique genetic structure significantly different from all  known TBEV subtypes was identified. This TBEV variant was  tentatively called “group 886”. Therefore, for this original TBEV  variant it was necessary to study the genetic, biological properties of the “group 886” strains, clarify its TBEV taxonomic status, its range, evolutionary history, etc.Aim. The generalization of the currently available data on genetic and biological properties of TBEV “886” group.Materials and methods. The genetic structure of “group 886” strains was studied by the complex of molecular-genetic methods (MHNA, sequencing of fragments or the complete genome).Results. It was shown that “group 886” strains form a separate cluster on phylogenetic tree, and the level of genetic differences  from other genotypes is more than 12 %. It was defined that this  TBEV variant has its own area (Irkutsk region, Republic of Buryatia,  Trans-Baikal region, Northern Mongolia). Its ecological connection  with all links of the transmissive chain (ixodid ticks, small mammals,  human), participation in human pathology, stability and duration of  circulation in the Baikal region, individual evolutionary history  were proved. Some phenotypic characteristics of the “group 886” strains were considered.Conclusion. The presented data testify to the validity of the “886 group” isolation as an independent genetic type. Taking into account  the geographical distribution of this TBEV genotype, we propose to assign it the name “Baikal genotype/subtype”

    Observation of Hadronic W Decays in t-tbar Events with the Collider Detector at Fermilab

    Full text link
    We observe hadronic W decays in t-tbar -> W (-> l nu) + >= 4 jet events using a 109 pb-1 data sample of p-pbar collisions at sqrt{s} = 1.8 TeV collected with the Collider Detector at Fermilab (CDF). A peak in the dijet invariant mass distribution is obtained that is consistent with W decay and inconsistent with the background prediction by 3.3 standard deviations. From this peak we measure the W mass to be 77.2 +- 4.6 (stat+syst) GeV/c^2. This result demonstrates the presence of two W bosons in t-tbar candidates in the W (-> l nu) + >= 4 jet channel.Comment: 20 pages, 4 figures, submitted to PR
    • …
    corecore