825 research outputs found

    A WIDE DISTRIBUTION OF A NEW VRN-B1c ALLELE OF WHEAT TRITICUM AESTIVUM L. IN RUSSIA, UKRAINE AND ADJACENT REGIONS: A LINK WITH THE HEADING TIME AND ADAPTIVE POTENTIAL

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    The adaptation of common wheat (T. aestivum L.) to diverse environmental conditions is greatly under the control of genes involved in determination of vernalization response (Vrn-1 genes). It was found that the variation in common wheat heading time is affected not only by combination of Vrn-1 homoeoalleles but also by multiple alleles at a separate Vrn-1 locus. Previously, we described the Vrn-B1c allele from T.aestivum cv. 'Saratovskaya 29' and found significant differences in the structure of the first (1st) intron of this allele when compared to another highly abundant Vrn-B1a allele, specifically, the deletion of 0.8 kb coupled with the duplication of 0.4 kb. We suggested that the changes in the intron 1 of Vrn-B1c allele caused earlier ear emergence in the near-isogenic line and cultivars, carrying this allele. In this study we investigate the distribution of the Vrn-B1c allele in a wide set of spring wheat cultivars from Russia, Ukraine and adjacent regions. The analysis revealed that 40% of Russian and 53% of Ukranian spring wheat cultivars contain the Vrn-B1c allele. The high distribution of the Vrn-B1c allele can be explained by a frequent using of 'Saratovskaya 29' in the breeding process inside the studied area. From the other hand, the predominance of the Vrn-B1c allele among cultivars cultivated in West Siberia and Kazakhstan may be due to the selective advantage of this allele for the region where there is a high risk of early fall frosts

    Tetranuclear Group 7/8 Mixed-Metal and Open Trinuclear Group 7 Metal Carbonyl Clusters Bearing Bridging 2-mercapto-1-methylimidazole Ligands

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    The reactivity of group 7 metal dinuclear carbonyl complexes [M2(CO)6(ÎŒ-SN2C4H5)2] (1, M = Re; 2, M = Mn) toward group 8 metal trinuclear carbonyl clusters were examined. Reactions of 1 and 2 with [Os3(CO)10(NCMe)2] in refluxing benzene furnished the tetranuclear mixed-metal clusters [Os3Re(CO)13(ÎŒ3-SN2C4H5)] (3) and [Os3Mn(CO)13(ÎŒ3-SN2C4H5)] (4), respectively. Similar treatment of 1 and 2 with Ru3(CO)12 yielded the ruthenium analogs [Ru3Re(CO)13(ÎŒ3-SN2C4H5)] (5), and [Ru3Mn(CO)13(ÎŒ3-SN2C4H5)] (6), but in the case of 2 a secondary product [Mn3(CO)10(ÎŒ-Cl)(ÎŒ3-SN2C4H5)2] (7) was also formed. Compounds 3–6 have a butterfly core of four metal atoms with the M (Mn or Re) at a wingtip of the butterfly and containing a noncrystallographic mirror plane of symmetry. This result provides a potential method for the synthesis of a series of new group 7/8 mixed metal complexes containing a bifunctional heterocyclic ligand. Compound 7 is a unique example of a 54-electron trimanganese complex having bridging 2-mercapto-1-methylimidazolate and chloride ligands. Interestingly, the reaction of 1 with Fe3(CO)12 at 70–75 °C furnished the tri- and dirhenium complexes [Re3(CO)10(ÎŒ-H)(ÎŒ3-SN2C4H5)2] (8) and [Re2(CO)6(N2C4H5)(ÎŒ-SN2C4H5)2] (9), respectively instead of the expected formation of the mixed-metal clusters. The former is an interesting example of a 52-electron trirhenium-hydridic complex containing bridging 2-mercapto-1-methylimidazolate ligand, while the latter can be viewed as a 1-methylimidazole adduct of 1. No mixed Fe–Re complexes were produced in this reaction. The molecular structures of the new compounds 3–5 and 7–9 were established by single-crystal X-ray diffraction analyses and the DFT studies of compounds 5, 7 and 8 are reported

    Genotyping of hexaploid wheat varieties from different Russian regions

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    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

    Harmonic Pulse Testing for Well Monitoring: application to a fractured geothermal reservoir

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    Harmonic Pulse Testing (HPT) has been developed as a type of well testing applicable during ongoing field operations because a pulsed signal is superimposed on background pressure trend. Its purpose is to determine well and formation parameters such as wellbore storage, skin, permeability and boundaries within the investigated volume. Compared to conventional well testing, HPT requires more time to investigate the same reservoir volume. The advantage is that it does not require the interruption of well and reservoir injection/production before and/or during the test because it allows the extraction of an interpretable periodic signal from measured pressure potentially affected by interference. This makes it an ideal monitoring tool. Interpretation is streamlined through diagnostic plots mimicking conventional well test interpretation methods. To this end, analytical solutions in the frequency domain are available. The methodology was applied to monitor stimulation operations performed at an Enhanced Geothermal System (EGS) site in Pohang, Korea. The activities were divided into two steps: first a preliminary sequence of tests, injection/fall‐off and two HPTs, characterized by low injection rates and dedicated to estimate permeability prior to stimulation operations; then stimulation sequence characterized by higher injection rate. During the stimulation operations other HPTs were performed to monitor formation properties behavior. The interpretation of HPT data through the derivative approach implemented in the frequency domain provided reliable results in agreement with the injection test. Moreover, it provided an estimation of hydraulic properties without cessation of stimulation operations, thus confirming the effectiveness of HPT application for monitoring purposes

    Hadron Properties just before Deconfinement

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    We have investigated hadron screening masses, the chiral condensate, and the pion decay constant close to the deconfinement phase transition in the confined phase of QCD. The simulations were done in the quenched approximation, on a lattice of size \mbox{323×832^{3}\times 8}. We examined temperatures ranging from 0.75\tc up to 0.92\tc. We see no sign of a temperature dependence in the chiral condensate or the meson properties, but some temperature dependence for the nucleon screening mass is not excluded.Comment: Postscript file, uuencoded compresse

    Label-free detection of DNA single-base mismatches using a simple reflectance-based optical technique

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    Rapid and quantitative detection of the binding of nucleic acids to surface-immobilized probes remains a challenge in many biomedical applications. We investigated the hybridization of a set of fully complementary and defected 12-base long DNA oligomers by using the Reflective Phantom Interface (RPI), a recently developed multiplexed label-free detection technique. Based on the simple measurement of reflected light intensity, this technology enables to quantify the hybridization directly as it occurs on the surface with a sensitivity of 10 pg mm-2. We found a strong effect of single-base mismatches and of their location on hybridization kinetics and equilibrium binding. In line with previous studies, we found that DNA-DNA binding is weaker on a surface than in the bulk. Our data indicate that this effect is a consequence of weak nonspecific binding of the probes to the surface

    Selective adsorption on fluorinated plastic enables the optical detection of molecular pollutants in water

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    Amorphous fluorinated plastic can be produced with a refractive index similar to that of water, a condition that makes it essentially invisible when immersed in aqueous solutions. Because of this property, even a small amount of adsorbed molecules on the plastic-water interface provides a detectable optical signal. We investigate two distinct substrates made of this material, characterized by different interface areas: a prism and a microporous membrane. We demonstrate that both substrates enable the label-free detection of molecular compounds in water even without any surface functionalization. The adsorption of molecules on the planar surface of the prism provides an increase of optical reflectivity, whereas the adsorption on the internal surface of the microporous membrane yields an increase of scattered light. Despite the different mechanisms, we find a similar optical response upon adsorption. We confirm this result by a theoretical model accounting for both reflection and scattering. We investigate the spontaneous adsorption process for different kinds of molecules: surfactants with different charges, a protein (lysozyme), and a constituent of gasoline (hexane). The measured equilibrium and kinetic constants for adsorption differ by orders of magnitudes among the different classes of molecules. By suitable analytical models, accounting for the effects of mass limitation and transport, we find a simple and general scaling of the adsorption parameters with the molecular size

    Molecular-cytogenetic analysis of triticale and wheat lines with introgressions of the tribe Triticeae species genetic material

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    There are a number of problems in selection of cultivated cereals associated with the requirements to create forms with resistance to diseases, pests and unfavorable environmental conditions. The genetic diversity of genes for resistance to biotic and abiotic stresses can be increased by means of the gene pool of wild and cultivated wheat relatives. To improve agronomic traits in cereals, we have developed common wheat hybrid lines T. aestivum/ T. durum, T. aestivum/ T. dicoccoides and triticale lines by crossing hexaploid triticale with common wheat forms with the substitution of genome D for the geno­me of diploid Aegilops species. The aim of the study was to identify the lines of common wheat and hexaploid triticale with alien introgression using cytological and molecular-genetic analyses and evaluation of their cytological stability. Comparative analysis of the structure of chromosomes by GISH and FISH methods, microsatellite- and chromosome-specific markers revealed that hybridization of triticale with genome-substitution forms of wheat leads to the reorganization of the genome, including both the introgression of foreign material and wheat chromosome rearrangements, which lead to new combinations of genetic loci. The efficiency of wheat microsatellite markers to characterize of the T. aestivum/ T. durum, T. aestivum/ T. dicoccum interspecific hybrid lines was shown. From 4 to 12 translocations of different lengths from T. durum and T. dicoccum were identified in the chromosomes of A and В genomes in the hybrid lines. Meiotic stability of wheat and triticale hybrids was found. It creates prerequisites for preservation of alien genetic material in subsequent generations

    Prospects for K+→π+ΜΜˉK^+ \to \pi^+ \nu \bar{ \nu } at CERN in NA62

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    The NA62 experiment will begin taking data in 2015. Its primary purpose is a 10% measurement of the branching ratio of the ultrarare kaon decay K+→π+ΜΜˉK^+ \to \pi^+ \nu \bar{ \nu }, using the decay in flight of kaons in an unseparated beam with momentum 75 GeV/c.The detector and analysis technique are described here.Comment: 8 pages for proceedings of 50 Years of CP

    Identification of microsatellite loci according to BAC sequencing data and their physical mapping to the bread wheat 5B chromosome

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    The shortage of polymorphic markers for the regions of wheat chromosomes that encode commercially valuable traits determined the need for studying wheat microsatellite loci. In this work, SSR markers for individual regions in the short arm of bread wheat chromosome 5B (5BS) were designed based on sequencing data for BAC clones, and the regions of the corresponding chromosome were saturated with these markers. Totally, 130 randomly selected BAC clones from the 5BS library were sequenced on the Ion Torrent platform and assembled in contigs using MIRA software. The assembly characteristics (N50 = 4 136 bp) are comparable to the recently obtained data for wheat and relative species and acceptable for identification of microsatellite loci. An algorithm utilizing the properties of complexity decompositions in  he sliding-window mode was used to detect DNA sequences with a repeat unit of 2–4 bp. Analysis of 17 770 contigs with the total length of 25 879 921 bp allowed for designing 113, 79, and 67 microsatellite (SSR) loci with a repeat unit of 2, 3, and 4 bp, respectively. The SSR markers with a motif of 3 bp were tested using nullitetrasomic lines of Chinese Spring wheat homoeologous group 5. Thus, 21 markers specific for chromosome 5B were detected. Eight of these markers were mapped to the distal region of this chromosome (bin 5BS6) using a set of Chinese Spring deletion lines for 5BS. Eight and four markers were mapped to the interstitial region (bins 5BS5 and 5BS4, respectively). One marker was mapped to a pericentromeric bin. A comparative analysis of the distribution of trinucleotide microsatellites over wheat chromosome 5B and in different cereal species suggests that the (AAG)n repeat has proliferated and has been maintained during the evolution of cereals
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