517 research outputs found
CRISPR
This review summarizes recent advances in endonuclease-mediated genome editing tools and research progress of genome-edited pigs as personalized test-systems for preclinical trials and as donors of organs with human-fit antigen profil
The study of agronomical traits determining productivity of Triticum aestivum/Triticum timopheevii introgression lines with resistance to fungal diseases
Development of resistant cultivars is one of the effective ways for protection of common wheat T. aestivum L. from fungal pathogens. The gene pool of wild and cultivated wheat relatives is often used for widening the wheat genetic diversity of resistance genes. However, alien genetic material introgressed into the wheat genome can contain genetic factors negatively affecting agronomically important traits. T. aestivum/ T. timopheevii introgression lines derived from different common wheat cultivars have characteristically good resistance to leaf rust and powdery mildew. A comparative assessment of these lines and initial wheat varieties during four field seasons revealed a significant effect of environmental factors on the phenotypic differences between traits that have relevance to productivity. Averaged data obtained for individual introgression lines and for cross combinations revealed both positive and negative tendencies in variations of agronomical traits. The positive effects include a significant increase in the numbers of tillers and spikelets per spike of the lines derived from cv. Skala. Reduction in spike productivity was found in groups of the lines derived from cv. Tselinnaya 20 and cv. Novosibirskaya 67. However, no significant differences in 1000-grain weight were found between most lines and original wheat cultivars. Analysis of the data obtained showed no apparent correlation between the reduction of agronomic traits and the amount of alien genetic material introgressed into the common wheat genome. T. aestivum/T. timopheevii introgression lines can be used as a source of resistance genes without reducing the yield of wheat cultivars
Localization of the quantitative trait loci related to lodging resistance in spring bread wheat (<i>Triticum aestivum</i> L.)
The yield and grain quality of spring and winter wheat significantly depends on varieties’ resistance to lodging, the genetic basis of this trait being quantitative and controlled by a large number of loci. Therefore, the study of the genetic architecture of the trait becomes necessary for the creation and improvement of modern wheat varieties. Here we present the results of localization of the genomic regions associated with resistance to lodging, plant height, and upper internode diameter in Russian bread wheat varieties. Phenotypic screening of 97 spring varieties and breeding lines was carried out in the field conditions of the West Siberian region during 2017–2019. It was found that 54 % of the varieties could be characterized as medium and highly resistant to lodging. At the same time, it was noted that the trait varied over the years. Twelve varieties showed a low level of resistance in all years of evaluation. Plant height-based grouping of the varieties showed that 19 samples belonged to semi-dwarfs (60–84 cm), and the rest were included in the group of standard-height plants (85–100 cm). Quantitative trait loci (QTL) mapping was performed by means of genome-wide association study (GWAS) using 9285 SNP markers. For lodging resistance, plant height, and upper internode diameter, 26 significant associations (–log p > 3) were found in chromosomes 1B, 2A, 3A, 3D, 4A, 5A, 5B, 5D, 6A, and 7B. The results obtained suggest that the regions of 700–711 and 597–618 Mb in chromosomes 3A and 6A, respectively, may contain clusters of genes that affect lodging resistance and plant height. No chromosome regions colocalized with the QTLs associated with lodging resistance or upper internode diameter were found. The present GWAS results may be important for the development of approaches for creating lodging-resistant varieties through marker-assisted and genomic selection
Lodging in wheat: genetic and environmental factors and ways of overcoming
Lodging is one of the main factors in reducing the yield and grain quality of winter and spring wheat varieties. The resistance of wheat cultivars to lodging largely depends on environmental factors, biological and morphological features of the stem and root systems. Selection of the varieties for resistance to lodging is relevant in many countries of the world and has a number of achievements. Plant height is one of the most important morphological characters associated with lodging resistance. Breeding of the varieties carrying the dwarfing genes (Rht) is the main direction to reduce the risk of lodging. The Rht-B1b, Rht-D1b, Rht8 and Rht11 genes are widely used throughout the world due to their significant influence on agronomically valuable traits, including lodging. It turned out to be important to study the anatomical and morphological features and chemical composition of stem tissues, which complement the assessment of resistance to lodging and allow the varietal material to be more fully characterized. The thickness of stem internodes and their anatomical structure play an important role in the stem strength. The diameter of the stem, its thickness and weight, a large number of vascular bundles and a wide ring of mechanical tissues correlate with resistance to lodging. The content of lignin, silicon and cellulose are important structural components and provide the stem strength of wheat plants. Molecular genetic analysis and mapping of genes and quantitative trait loci are of great importance in identifying the genetic basis of the relationship between the anatomical and morphophysiological characters of the stem and root system and lodging. Genetic factors reflecting correlations between the lodging and the thickness of the stem wall, the number of vascular bundles and other characters were mapped to chromosomes 1A, 1B, 2A, 2D, 3A, 4B, 4D, 5A, 5D, 6D and 7D. It has been found that loci with high phenotypic effects on lodging tolerance are colocalized with loci responsible for plant height, stem diameter and stem strength. To increase resistance to lodging, it is necessary to develop a set of agrotechnical methods that reduce the influence of soil and climatic factors and create wheat varieties tolerant to lodging
Multicolour CCD photometric study of galactic star clusters SAI 63 and SAI 75
We present U B V I CCD photometric observations obtained in the field of open clusters SAI 63 and SAI 75. CCD optical data obtained for the first time for these clusters are used to derive the fundamental parameters of the clusters. Stellar surface density profile indicates that radii of SAI 63 and SAI 75 are ∼3′.5 and 2′.5 respectively. The reddenings E(B−V) are 0.44±0.05 and 0.34±0.05 mag for SAI 63 and SAI 75 respectively while the corresponding distances are 2.2 ± 0.2 and 3.5±0.3 kpc. An age of 450 ± 50 Myr for SAI 63 and 90 ± 10 Myr for SAI 75 is determined using the theoretical isochrones of Z=0.019. Our analysis shows that reddening law is normal towards SAI 75
Effect of triazavirine on the outcome of a lethal influenza infection and secondary bacterial pneumonia following influenza in mice
Pneumonia often occurs as secondary infection post influenza disease and accounts for a large proportion of the morbidity and mortality associated with seasonal and pandemic influenza outbreaks. The antiviral drug triazavirine is licensed in Russia for the treatment and prophylaxis of acute respiratory infections, including influenza A and B viruses. In the present study, we investigated the efficacy of triazavirine in a mouse model of secondary Staphylococcus aureus pneumonia following A/California/04/2009 (H1N1)pdm09 influenza virus infection. We also performed a study of the efficacy of triazavirine against the A/California/04/2009 (H1N1)pdm09 lethal influenza infection in mice. In this model, triazavirine at the dose of 25 mg/kg/day significantly enhanced the survival of animals (60% compared to 20%) and the mean survival time to death, prevented weight loss, and reduced viral titer in the lungs of mice infected with influenza virus. At doses of 50 and 100 mg/kg/day, triazavirine was highly effective in the treatment of the secondary bacterial pneumonia following influenza infection in mice. At these doses, triazavirine protected 67-75% of animals against death, increased the mean survival time to death by twofold, and reduced the virus titer by 2.2-3.0 log10TCID50/ml compared to the mice in the control group. These findings suggest the possible benefit of triazavirine treatment in reducing post influenza pneumonia incidence in humans.Pneumonia often occurs as secondary infection post influenza disease and accounts for a large proportion of the morbidity and mortality associated with seasonal and pandemic influenza outbreaks. The antiviral drug triazavirine is licensed in Russia for the treatment and prophylaxis of acute respiratory infections, including influenza A and B viruses. In the present study, we investigated the efficacy of triazavirine in a mouse model of secondary Staphylococcus aureus pneumonia following A/California/04/2009 (H1N1)pdm09 influenza virus infection. We also performed a study of the efficacy of triazavirine against the A/California/04/2009 (H1N1)pdm09 lethal influenza infection in mice. In this model, triazavirine at the dose of 25 mg/kg/day significantly enhanced the survival of animals (60% compared to 20%) and the mean survival time to death, prevented weight loss, and reduced viral titer in the lungs of mice infected with influenza virus. At doses of 50 and 100 mg/kg/day, triazavirine was highly effective in the treatment of the secondary bacterial pneumonia following influenza infection in mice. At these doses, triazavirine protected 67-75% of animals against death, increased the mean survival time to death by twofold, and reduced the virus titer by 2.2-3.0 log10TCID50/ml compared to the mice in the control group. These findings suggest the possible benefit of triazavirine treatment in reducing post influenza pneumonia incidence in humans
Automated search for star clusters in large multiband surveys: II. Discovery and investigation of open clusters in the Galactic plane
Automated search for star clusters in J,H,K_s data from 2MASS catalog has
been performed using the method developed by Koposov et. al (2008). We have
found and verified 153 new clusters in the interval of the galactic latitude
-24 < b < 24 degrees. Color excesses E(B-V), distance moduli and ages were
determined for 130 new and 14 yet-unstudied known clusters. In this paper, we
publish a catalog of coordinates, diameters, and main parameters of all the
clusters under study. A special web-site available at http://ocl.sai.msu.ru has
been developed to facilitate dissemination and scientific usage of the results.Comment: 9 pages, 3 tables, 5 figures, accepted to Astronomy Letter
Features of epigenetic dolomite transformations in the Syukeyevskoye bitumen field
Syukeyevskoye bitumen field is one of perspective for development of open pit mining in western part of the Republic of Tatarstan. Basically two predominant stages in the process of epigenetic rock transformations were discriminated on the basis of field and laboratory data. The first stage associates with the fluids penetration in biomicritic dolomites and the hydrocarbon accumulation. The second stage associates with hydrocarbon oxidation. One can resume that leaching processes dominate at the stage of hydrocarbons penetration within dolomite rocks, and metasomatic processes dominate at hydrocarbon oxidation stage. These features can be used as key for understanding rock formation history in other similar cases
Genotyping of hexaploid wheat varieties from different Russian regions
We used molecular-genetic and molecular-cytology approaches to characterize the genomes of 20 varieties of wheat created in different regions of Russia. A molecular-genetic analysis was performed using 29 SSR-markers covering the entire genome, and 41 ISBP-markers localized on chromosome 5B. Analysis of genetic similarity based on the results of molecular genotyping showed that the winter wheat varieties form a common cluster, regardless of the origin or area of cultivation. This is primarily due to the fact that the varieties originating from the European part of Russia were used to establish winter wheat varieties for West Siberia. Comparative analysis of individual dendrograms constructed using 1–2 markers per chromosome, and with the involvement of a larger number of 5B-chromosome markers allowed us to identify varieties with rearrangements of this chromosome and to assess genetic diversity. We found that winter wheat Vassa and spring wheat Chelyaba 75 were clustered closely together. This is an indirect confirmation of the use of winter wheat varieties in the breeding to improve the productive potential of spring wheat. Molecular-cytology analysis by C-banding and fluorescence in situ hybridization (FISH) revealed various chromosomal rearrangements in 8 of 20 cultivars studied, including translocations from S. cereale, Ae. speltoides and Th. intermedium. Thus, a combination of the two approaches allowed us to better characterize genomes of wheat varieties of various origin
APATITE SHELLS OF THE DEVONIAN FORAMINIFERS (SAFYANOVSKY COPPER-SULPHIDE DEPOSIT, MIDDLE URAL)
Relevance of the work is due to the possibility of a detailed study of Devonian foraminifers with apatite shells and the reconstruction of specific conditions for their formation. Foraminifer shells are morphologically similar to Parathurammina aff. tamarae L. Petrova, 1981, the Eifelian-the Givetian, which were found in thin sections of samples of carboniferous and chiselly aleuropelites of the ore-bearing strata of the Safyanovsky copper-sulphide deposit (Middle Urals) for the first time.
Purpose of work. Detailed study of the shells of Devonian foraminifers similar to Parathurammina aff. tamarae L. Petrova, 1981, as well as reconstruction of sedimentation conditions for carboniferous and chiselly rocks of the ore-bearing strata of the Safyanovsky copper-sulphide deposit.
Research methodology. Shells were studied in thin sections of carboniferous and chiselly aleuropelite samples. The detailed study of morphology and composition of the shells was carried out using a scanning electron microscope JSM-6390LV (JEOL) with an energy-dispersive spectrometer Inca Energy 450, an electron microscope Tescan and an electron probe microanalyzer Cameca SX100.
Results. Size and morphology of the shells were determined; it was also found that the walls of the shells of the studied foraminifers were represented by fluorapatite. It was assumed that initially they were calcareous, and subsequently were replaced by apatite and quartz. However, more detailed studies did not reveal traces of substitution of carbonate rock for apatite.
Conclusions. Compared with Parathurammina aff. tamarae L. Petrova, 1981, shells have a reduced size and a smaller number of fauces, which can be explained by unfavorable habitats in a shallow sea basin, where carbonate sedimentation was suppressed by a significant influx of volcanic material. The presence of sulfide minerals in nucleus of shells may indicate to the specific habitat (pH of the environment, salinity of supra-bottom water) of foraminifers. Findings of fossils of green, siphon algae together with studied foraminifers indicate that formation of the original substrate took place in near-surface layers (up to 200 m) of the photic zone of seas
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